|  |  |  | | | | | TERMSC | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Neurogenic differentiation of human conjunctiva mesenchymal stem cells on a nanofibrous scaffold. Int J Dev Biol. 2010;54(8-9):1295-1300 Authors: Soleimani M, Nadri S, Shabani I The selection of a good quality scaffold is an essential strategy for tissue engineering. Ideally, the scaffold should be a functional and structural biomimetic of the native extracellular matrix and support multiple tissue morphogenesis. However, investigators have previously shown that three-dimensional nanofibrous scaffolds are capable of influencing cellular behavior. In this study, we experimented with a three-dimensional nanofibrous scaffold fabricated from aligned-poly L-lactic acid (PLLA) for its ability to support neurogenic and hinder dopaminergic differentiation of conjunctiva mesenchymal stem cells (CJMSCs) in vitro. In this work, CJMSCs were seeded onto nanofibrous scaffolds, and were induced to differentiate along neurogenic lineages by culturing in specific differentiation media. Scanning electron microscopy imaging, RT-PCR and immunocytochemistry were used to analyze cultivated CJMSCs on scaffold and their expression of neurogenic-specific markers. We found a lack of expression of dopaminergic genes in CJMSCs seeded on align PLLA scaffold, while neurocyte-cell markers including Nestin, NSE, MAP-2 and beta-Tubulin III were expressed in these cells. On the basis of these experimental results, we conclude that the nanofibrous PLLA scaffold reported herein could be used as a potential cell carrier in neural tissue engineering and that these scaffolds could be useful for the partial inhibition of the dopaminergic differentiation of CJMSCs. PMID: 20857376 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Osteoclastic cell behaviors affected by the α-tricalcium phosphate based bone cements. J Mater Sci Mater Med. 2010 Sep 21; Authors: Oh SA, Lee GS, Park JH, Kim HW Calcium phosphate cements (CPCs) have recently gained great interest as injectable bone substitutes for use in dentistry and orthopedics. α-tricalcium phosphate (α-TCP) is a popularly used precursor powder for CPCs. When mixed with appropriate content of liquid and kept under aqueous conditions, α-TCP dissolves to form a calcium-deficient hydroxyapatite and then hardens to cement. In this study, α-TCP based cement (CP) and its composite cement with chitosan (Ch-CP) were prepared and the osteoclastic responses to the cements and their elution products were evaluated. Preliminary evaluation of the cements revealed that the CP and Ch-CP hardened within ~10 min at an appropriate powder-to-liquid ratio (PL) of 3.0. In addition, CP and Ch-CP were transformed into an apatite phase following immersion in a saline solution. Moreover, the osteoblastic cells were viable on the cements for up to 10 days. Mouse-derived bone marrow cells were isolated and activated with osteoclastic differentiation medium, and the effects of the CP and Ch-CP substrates and their ionic eluants on the osteoclastic activity were investigated. Osteoclastic cells were viable for up to 14 days on both types of cements, maintaining a higher cell growth level than the control culture dish. Multi-nucleated osteoclastic cells that were tartrate-resistant acid phosphatase (TRAP)-positive were clearly observed when cultured on the cement substrates as well as treated with the cement eluants. The TRAP activity was found to be significantly higher in cells influenced by the cement substrates and their eluants with respect to the control culture dish (Ch-CP > CP ≫ control). Overall, the osteoclastic differentiation was highly stimulated by the α-TCP based experimental cements in terms of both the substrate interaction and their elution products. PMID: 20857323 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Static and dynamic cultivation of bone marrow stromal cells on biphasic calcium phosphate scaffolds derived from an indirect rapid prototyping technique. J Mater Sci Mater Med. 2010 Sep 21; Authors: Schumacher M, Uhl F, Detsch R, Deisinger U, Ziegler G The adequate regeneration of large bone defects is still a major problem in orthopaedic surgery. Synthetic bone substitute materials have to be biocompatible, biodegradable, osteoconductive and processable into macroporous scaffolds tailored to the patient specific defect. Hydroxyapatite (HA) and tricalcium phosphate (TCP) as well as mixtures of both phases, biphasic calcium phosphate ceramics (BCP), meet all these requirements and are considered to be optimal synthetic bone substitute materials. Rapid prototyping (RP) can be applied to manufacture scaffolds, meeting the criteria required to ensure bone ingrowth such as high porosity and defined pore characteristics. Such scaffolds can be used for bone tissue engineering (BTE), a concept based on the cultivation of osteogenic cells on osteoconductive scaffolds. In this study, scaffolds with interconnecting macroporosity were manufactured from HA, TCP and BCP (60 wt% HA) using an indirect rapid prototyping technique involving wax ink-jet printing. ST-2 bone marrow stromal cells (BMSCs) were seeded onto the scaffolds and cultivated for 17 days under either static or dynamic culture conditions and osteogenic stimulation. While cell number within the scaffold pore system decreased in case of static conditions, dynamic cultivation allowed homogeneous cell growth even within deep pores of large (1,440 mm(3)) scaffolds. Osteogenic cell differentiation was most advanced on BCP scaffolds in both culture systems, while cells cultured under perfusion conditions were generally more differentiated after 17 days. Therefore, scaffolds manufactured from BCP ceramic and seeded with BMSCs using a dynamic culture system are the method of choice for bone tissue engineering. PMID: 20857322 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Silver/poly (lactic acid) nanocomposites: preparation, characterization, and antibacterial activity. Int J Nanomedicine. 2010;5:573-579 Authors: Shameli K, Ahmad MB, Yunus WM, Ibrahim NA, Rahman RA, Jokar M, Darroudi M In this study, antibacterial characteristic of silver/poly (lactic acid) nanocomposite (Ag/PLA-NC) films was investigated, while silver nanoparticles (Ag-NPs) were synthesized into biodegradable PLA via chemical reduction method in diphase solvent. Silver nitrate and sodium borohydride were respectively used as a silver precursor and reducing agent in the PLA, which acted as a polymeric matrix and stabilizer. Meanwhile, the properties of Ag/PLA-NCs were studied as a function of the Ag-NP weight percentages (8, 16, and 32 wt% respectively), in relation to the use of PLA. The morphology of the Ag/PLA-NC films and the distribution of the Ag-NPs were also characterized. The silver ions released from the Ag/PLA-NC films and their antibacterial activities were scrutinized. The antibacterial activities of the Ag/PLA-NC films were examined against Gram-negative bacteria (Escherichia coli and Vibrio parahaemolyticus) and Gram-positive bacteria (Staphylococcus aureus) by diffusion method using Muller-Hinton agar. The results indicated that Ag/PLA-NC films possessed a strong antibacterial activity with the increase in the percentage of Ag-NPs in the PLA. Thus, Ag/PLA-NC films can be used as an antibacterial scaffold for tissue engineering and medical application. PMID: 20856832 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Nanotechnology: what is it and why is small so big? Can J Ophthalmol. 2010 Oct 20;45(5):1-8 Authors: Leary JF SIZE matters… the size of the scalpel determines the precision of the surgery. Nanotechnology affords us the chance to construct nanotools that are on the size scale of molecules, allowing us to treat each cell of the human body as a patient. Nanomedicine will allow for eradication of disease at the single-cell level. Since nanotools are self-assembling, nanomedicine has the potential to perform parallel processing medicine on a massive scale. These nanotools can be made of biocompatible and biodegradable nanomaterials. They can be “smart” in that they can use sophisticated targeting strategies, which can perform error checking to prevent harm if even a very small fraction of them are mistargeted. Built-in molecular biosensors can provide controlled drug delivery with feedback control for individual cell dosing. If designed to repair existing cells rather than to just destroy diseased cells, these nanomedical devices can perform in-situ regenerative medicine, programming cells along less dangerous cell pathways to prevent tissues and organs from being destroyed by the treatments and thus providing an attractive alternative to allogeneic organ transplants. Nanomedical tools, while tiny in size, can have a huge impact on medicine and health care. Earlier and more sensitive diagnosis will lead to presymptomatic diagnosis and treatment of disease before permanent damage occurs to tissues and organs. This should result in the delivery of better medicine at lower costs with better outcomes. Lastly, and importantly, some of the first uses of nanotechnology and nanomedicine are occurring in the field of ophthalmology. Some of the potential benefits of nanotechnology for future treatment of retinopathies and optic nerve damage are discussed at the end of this paper. PMID: 20856270 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Implantation of atelocollagen sheet for vocal fold scar. Curr Opin Otolaryngol Head Neck Surg. 2010 Sep 19; Authors: Kishimoto Y, Welham NV, Hirano S PURPOSE OF REVIEW: This article reviews recent advances in scaffold-based interventions for the treatment of vocal fold scarring, with a particular emphasis on atelocollagen sheet implantation in the vocal fold lamina propria. RECENT FINDINGS: Scaffold-based therapies have demonstrated therapeutic promise in both preclinical and early clinical studies. Recent research has begun to shed light on the interactions between scaffold material properties, encapsulated and infiltrating cells, stimulatory molecules such as growth factors, and external regulatory variables such as stress, strain, and vibration. The atelocollagen sheet, a cross-linked collagen material with abundant micropores, has an established clinical track record as a scaffold for dermal and epidermal repair and exhibited potential therapeutic benefit in a recent study of patients with vocal fold scarring and sulcus vocalis. SUMMARY: Scaffolding is one of the useful tools in tissue engineering and atelocollagen sheet implantation has been shown to be effective in vocal fold regeneration. However, many of the scaffold materials under investigation still await clinical translation and those that have been investigated in human patients (such as the atelocollagen sheet) require additional research in appropriately powered placebo-controlled studies. PMID: 20856118 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | An update on auricular reconstruction: three major auricular malformations of microtia, prominent ear and cryptotia. Curr Opin Otolaryngol Head Neck Surg. 2010 Sep 19; Authors: Park C, Yoo YS, Hong ST PURPOSE OF REVIEW: Microtia, prominent ear, and cryptotia are the most common types of auricular malformations. This review provides updated information on these types of reconstructions, in addition to recalling previously accepted surgical methods. RECENT FINDINGS: Autogenous costal cartilage is still considered as an ideal material for framework fabrication in microtia reconstruction. Many surgeons have adopted the Nagata approach, the Brent approach, or variations of the two, in their work. With these employed techniques, auricles reconstructed by experienced surgeons have proven to be aesthetically promising. However, with regards to the harvesting of the costal cartilage, the underdevelopment of the chest wall donor site, alopecia of the scalp, and scarring of the postauricular-mastoid region are still considered problematic aspects of these approaches. Some articles have described attempts to solve these problems, whereas some experiments in cartilage production using tissue engineering techniques have shown promise in their initial stages of development.It is generally accepted that prominent ears should be corrected through a combination of sculpting and suture techniques, according to the individual shape and the quality of the ear prominence.Most of the cryptotia malformations show not only embedded upper auricles, but also associated adhesions of the upper auricular cartilage. Their correction should therefore resolve both deformities. SUMMARY: A number of articles highlighting clinical experiences with auricular reconstructions for microtia, prominent ear, and cryptotia have been included in this review. We believe that the information synthesized here will become a basis for further development of auricular reconstruction techniques. PMID: 20856117 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Bilateral Orbitozygomatic Reconstruction With Tissue-Engineered Bone. J Craniofac Surg. 2010 Sep;21(5):1612-1614 Authors: Taylor JA Critical defects of the craniomaxillofacial region and long bones are often treated with bone grafts and vascularized osteocutaneous free flaps. These lengthy operations may be associated with considerable donor site morbidity and often have suboptimal functional and aesthetic results. The allure of providing an exact replica of a missing bone that incorporates to become indistinguishable from self, has the capacity to heal and grow, is resistant to infection, and with minimal morbidity is a "holy grail" to all surgeons who work with bone. This is a report of a 14-year-old adolescent boy with Treacher Collins syndrome whose bilateral orbitozygomatic defects were treated with engineered bone made from a combination of human bone allograft, adipose-derived mesenchymal stem cells, bone morphogenic protein-2, and periosteal grafts. This single-stage reconstruction was followed by an exuberant amount of postoperative swelling that persisted for 3 weeks. He had slight lid malposition postoperatively as well but has had no long-term negative effects from the surgery. His reconstruction has remained stable during a 6-month follow-up, and a recent biopsy of the engineered bone demonstrated healthy, lamellar bone. These data are the first to demonstrate revitalization of large volume allograft bone in humans and have positive implications for craniofacial bone tissue engineering. The combination of adipose-derived stem cells, bone morphogenic protein-2, bone allograft, and periosteum may provide an alternative method to both osteocutaneous free flaps and large structural allografts with less morbidity and improved long-term results. PMID: 20856057 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Autophagy in cancer associated fibroblasts promotes tumor cell survival: Role of hypoxia, HIF1 induction and NFκB activation in the tumor stromal microenvironment. Cell Cycle. 2010 Sep 9;9(17) Authors: Martinez-Outschoorn UE, Trimmer C, Lin Z, Whitaker-Menezes D, Chiavarina B, Zhou J, Wang C, Pavlides S, Martinez-Cantarin MP, Capozza F, Witkiewicz AK, Flomenberg N, Howell A, Pestell RG, Caro J, Lisanti MP, Sotgia F Recently, using a co-culture system, we demonstrated that MCF7 epithelial cancer cells induce oxidative stress in adjacent cancer-associated fibroblasts, resulting in the autophagic/lysosomal degradation of stromal caveolin-1 (Cav-1). However, the detailed signaling mechanism(s) underlying this process remain largely unknown. Here, we show that hypoxia is sufficient to induce the autophagic degradation of Cav-1 in stromal fibroblasts, which is blocked by the lysosomal inhibitor chloroquine. Concomitant with the hypoxia-induced degradation of Cav-1, we see the upregulation of a number of well-established autophagy/mitophagy markers, namely LC3, ATG16L, BNIP3, BNIP3L, HIF-1α and NFκB. In addition, pharmacological activation of HIF-1α drives Cav-1 degradation, while pharmacological inactivation of HIF-1 prevents the downregulation of Cav-1. Similarly, pharmacological inactivation of NFκB-another inducer of autophagy-prevents Cav-1 degradation. Moreover, treatment with an inhibitor of glutathione synthase, namely BSO, which induces oxidative stress via depletion of the reduced glutathione pool, is sufficient to induce the autophagic degradation of Cav-1. Thus, it appears that oxidative stress mediated induction of HIF1- and NFκB-activation in fibroblasts drives the autophagic degradation of Cav-1. In direct support of this hypothesis, we show that MCF7 cancer cells activate HIF-1α- and NFκB-driven luciferase reporters in adjacent cancer-associated fibroblasts, via a paracrine mechanism. Consistent with these findings, acute knock-down of Cav-1 in stromal fibroblasts, using an siRNA approach, is indeed sufficient to induce autophagy, with the upregulation of both lysosomal and mitophagy markers. How does the loss of stromal Cav-1 and the induction of stromal autophagy affect cancer cell survival? Interestingly, we show that a loss of Cav-1 in stromal fibroblasts protects adjacent cancer cells against apoptotic cell death. Thus, autophagic cancer-associated fibroblasts, in addition to providing recycled nutrients for cancer cell metabolism, also play a protective role in preventing the death of adjacent epithelial cancer cells. We demonstrate that cancer-associated fibroblasts upregulate the expression of TIGAR in adjacent epithelial cancer cells, thereby conferring resistance to apoptosis and autophagy. Finally, the mammary fat pads derived from Cav-1 (-/-) null mice show a hypoxia-like response in vivo, with the upregulation of autophagy markers, such as LC3 and BNIP3L. Taken together, our results provide direct support for the "Autophagic Tumor Stroma Model of Cancer Metabolism", and explain the exceptional prognostic value of a loss of stromal Cav-1 in cancer patients. Thus, a loss of stromal fibroblast Cav-1 is a biomarker for chronic hypoxia, oxidative stress and autophagy in the tumor microenvironment, consistent with its ability to predict early tumor recurrence, lymph node metastasis and tamoxifen-resistance in human breast cancers. Our results imply that cancer patients lacking stromal Cav-1 should benefit from HIF-inhibitors, NFκB-inhibitors, anti-oxidant therapies, as well as autophagy/lysosomal inhibitors. These complementary targeted therapies could be administered either individually or in combination, to prevent the onset of autophagy in the tumor stromal compartment, which results in a "lethal" tumor microenvironment. PMID: 20855962 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Human embryonic stem cell-derived cardiomyocytes engraft but do not alter cardiac remodeling after chronic infarction in rats. J Mol Cell Cardiol. 2010 Sep 17; Authors: Fernandes S, Naumova AV, Zhu WZ, Laflamme MA, Gold J, Murry CE BACKGROUND: Previous studies indicated that, in an acute myocardial infarction model, human embryonic stem cell-derived cardiomyocytes (hESC-CM) injected with a pro-survival cocktail (PSC) can preserve contractile function. Because patients with established heart failure may also benefit from cell transplantation, we evaluated the physiological effects of hESC-CM transplanted into a chronic model of myocardial infarction. METHODS AND RESULTS: Intramyocardial injection of hESC-CM with PSC was performed in nude rats at 1month following ischemia-reperfusion. The left ventricular function of hESC-CM injected rats was evaluated at 1, 2 and 3months after the cell injection procedure and was compared to 3 control groups (rats injected with serum-free media, PSC-only, or non-cardiac human cells in PSC). Histology at 3months revealed that human cardiomyocytes survive, develop increased sarcomere organization and are still proliferating. Despite successful engraftment, both echocardiography and MRI analyses showed no significant difference in left ventricular structure or function between these 4 groups at any time point of the study, suggesting that human cardiomyocytes do not affect cardiac remodeling in a rat model of chronic myocardial infarction. CONCLUSION: When injected into a chronic infarct model, hESC-CM can engraft, survive and form grafts with striated cardiomyocytes at least as well as was previously observed in an acute myocardial infarction model. However, although hESC-CM transplantation can attenuate the progression of heart failure in an acute model, the same hESC-CM injection protocol is insufficient to restore heart function or to alter adverse remodeling of a chronic myocardial infarction model. PMID: 20854826 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Neovascularization by bFGF releasing hyaluronic acid-gelatin microspheres: in vitro and in vivo studies. Growth Factors. 2010 Sep 21; Authors: Demirdögen B, Elçin AE, Elçin YM Therapeutic angiogenesis with angiogenic growth factors has been described as a promising approach for tissue engineering, wound healing, and for treating ischemic tissues. Here, we assessed the merit of heparin-entrapped hyaluronic acid-gelatin (HA-G) microspheres for the sustained release of recombinant basic fibroblast growth factor (rbFGF) to promote localized neovascularization. HA-G microspheres were prepared by a water-in-oil emulsion method, and the in vitro release kinetics were first examined using three model proteins. Then, bFGF was incorporated into microspheres, and the bioactivity of the in vitro-released rbFGF was tested on human umbilical vein endothelial cell cultures. The ability to promote microvessel growth was assessed in vivo, at the subcutaneous groin fascia of Wistar rats after 3, 7, 14, and 21 days. Histological and morphometrical analysis indicated that heparin-entrapped HA-G microspheres have the capacity to release bioactive rbFGF, leading to localized neovascularization in the rat subcutaneous tissue. PMID: 20854186 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stromal stem cells from adipose tissue and bone marrow of age matched female donors display distinct immunophenotypic profiles. J Cell Physiol. 2010 Sep 20; Authors: Pachón-Peña G, Yu G, Tucker A, Wu X, Vendrell J, Bunnell B, Gimble J Adipose tissue is composed of lipid-filled mature adipocytes and a heterogeneous stromal vascular fraction (SVF) population of cells. Similarly, the bone marrow (BM) is composed of multiple cell types including adipocytes, hematopoietic, osteoprogenitor, and stromal cells necessary to support hematopoiesis. Both adipose and BM contain a population of mesenchymal stromal/stem cells with the potential to differentiate into multiple lineages, including adipogenic, chondrogenic, and myogenic cells, depending on the culture conditions. In this study we have shown that human adipose derived stem cells (ASCs) and bone marrow mesenchymal stem cells (BMSCs) populations display a common expression profile for many surface antigens, including CD29, CD49c, CD147, CD166, and HLA-abc. Nevertheless, significant differences were noted in the expression of CD34 and its related protein, PODXL, CD36, CD 49f, CD106, and CD146. Furthermore, ASCs displayed more pronounced adipogenic differentiation capability relative to BMSC based on Oil Red staining (7 vs. 2.85 fold induction). In contrast, no difference between the stem cell types was detected for osteogenic differentiation based on Alizarin Red staining. Analysis by RT-PCR demonstrated that both the ASC and BMSC differentiated adipocytes and osteoblast displayed a significant upregulation of lineage specific mRNAs relative to the undifferentiated cell populations; no significant differences in fold mRNA induction was noted between ASCs and BMSCs. In conclusion, these results demonstrate human ASCs and BMSCs display distinct immunophenotypes based on surface positivity and expression intensity as well as differences in adipogenic differentiation. The findings support the use of both human ASCs and BMSCs for clinical regenerative medicine. J. Cell. Physiol. © 2010 Wiley-Liss, Inc. PMID: 20857424 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Instructive Materials for Functional Tissue Engineering. Macromol Biosci. 2010 Sep 20; Authors: Driessen-Mol A, Bouten CV, Baaijens FP PMID: 20857393 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Bioactive Scaffolds for Engineering Vascularized Cardiac Tissues. Macromol Biosci. 2010 Sep 20; Authors: Chiu LL, Radisic M, Vunjak-Novakovic G Functional vascularization is a key requirement for the development and function of most tissues, and most critically cardiac muscle. Rapid and irreversible loss of cardiomyocytes during cardiac infarction directly results from the lack of blood supply. Contractile cardiac grafts, engineered using cardiovascular cells in conjunction with biomaterial scaffolds, are an actively studied method for cardiac repair. In this article, we focus on biomaterial scaffolds designed to mediate the development and maturation of vascular networks, by immobilized growth factors. The interactive effects of multiple vasculogenic factors are discussed in the context of cardiac tissue engineering. PMID: 20857391 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Post-Plasma Grafting of AEMA as a Versatile Tool to Biofunctionalise Polyesters for Tissue Engineering. Macromol Biosci. 2010 Sep 20; Authors: Desmet T, Billiet T, Berneel E, Cornelissen R, Schaubroeck D, Schacht E, Dubruel P In the last decade, substantial research in the field of post-plasma grafting surface modification has focussed on the introduction of carboxylic acids on surfaces by grafting acrylic acid (AAc). In the present work, we report on an alternative approach for biomaterial surface functionalisation. Thin poly-ε-caprolactone (PCL) films were subjected to a dielectric barrier discharge Ar-plasma followed by the grafting of 2-aminoethyl methacrylate (AEMA) under UV-irradiation. X-ray photoelectron spectroscopy (XPS) confirmed the presence of nitrogen. The ninhydrin assay demonstrated, both quantitatively and qualitatively, the presence of free amines on the surface. Confocal fluorescence microscopy (CFM), atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to visualise the grafted surfaces, indicating the presence of pAEMA. Static contact angle (SCA) measurements indicated a permanent increase in hydrophilicity. Furthermore, the AEMA grafted surfaces were applied for comparing the physisorption and covalent immobilisation of gelatin. CFM demonstrated that only the covalent immobilisation lead to a complete coverage of the surface. Those gelatin-coated surfaces obtained were further coated using fibronectin. Osteosarcoma cells demonstrated better cell-adhesion and cell-viability on the modified surfaces, compared to the pure PCL films. PMID: 20857390 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Multifunctional Hybrid Three-dimensionally Woven Scaffolds for Cartilage Tissue Engineering. Macromol Biosci. 2010 Sep 20; Authors: Moutos FT, Estes BT, Guilak F The successful replacement of large-scale cartilage defects or osteoarthritic lesions using tissue-engineering approaches will likely require composite biomaterial scaffolds that have biomimetic mechanical properties and can provide cell-instructive cues to control the growth and differentiation of embedded stem or progenitor cells. This study describes a novel method of constructing multifunctional scaffolds for cartilage tissue engineering that can provide both mechanical support and biological stimulation to seeded progenitor cells. 3-D woven PCL scaffolds were infiltrated with a slurry of homogenized CDM of porcine origin, seeded with human ASCs, and cultured for up to 42 d under standard growth conditions. These constructs were compared to scaffolds derived solely from CDM as well as 3-D woven PCL fabric without CDM. While all scaffolds promoted a chondrogenic phenotype of the ASCs, CDM scaffolds showed low compressive and shear moduli and contracted significantly during culture. Fiber-reinforced CDM scaffolds and 3-D woven PCL scaffolds maintained their mechanical properties throughout the culture period, while supporting the accumulation of a cartilaginous extracellular matrix. These findings show that fiber-reinforced hybrid scaffolds can be produced with biomimetic mechanical properties as well as the ability to promote ASC differentiation and chondrogenesis in vitro. PMID: 20857388 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Immunohistochemical parcellation of the ferret (Mustela putorius) visual cortex reveals substantial homology with the cat (Felis catus). J Comp Neurol. 2010 Nov 1;518(21):4439-62 Authors: Homman-Ludiye J, Manger PR, Bourne JA Electrophysiological mapping of the adult ferret visual cortex has until now determined the existence of 12 retinotopically distinct areas; however, in the cat, another member of the Carnivora, 20 distinct visual areas have been identified by using retinotopic mapping and immunolabeling. In the present study, the immunohistochemical approach to demarcate the areal boundaries of the adult ferret visual cortex was applied in order to overcome the difficulties in accessing the sulcal surfaces of a small, gyrencephalic brain. Nonphosphorylated neurofilament (NNF) expression profiles were compared with another classical immunostain of cortical nuclei, Cat-301 chondroitin sulfate proteoglycan (CSPG). Together, these two markers reliably demarcated the borders of the 12 previously defined areas and revealed further arealization beyond those borders to a total of 19 areas: 21a and 21b; the anterolateral, posterolateral, dorsal, and ventral lateral suprasylvian areas (ALLS, PLLS, DLS, and VLS, respectively); and the splenial and cingulate visual areas (SVA and CVA). NNF expression profile and location of the newly defined areas correlate with previously defined areas in the cat. Moreover, NNF and Cat-301 together revealed discrete expression domains in the posteroparietal (PP) cortex, demarcating four subdivisions in the caudal lateral and medial domains (PPcL and PPcM) and rostral lateral and medial domains (PPrL and PPrM), where only two retinotopic maps have been previously identified (PPc and PPr). Taken together, these studies suggest that NNF and Cat-301 can illustrate the homology between cortical areas in different species and draw out the principles that have driven evolution of the visual cortex. J. Comp. Neurol. 518:4439-4462, 2010. © 2010 Wiley-Liss, Inc. PMID: 20853515 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Adipose tissue engineering from adult human stem cells: a new concept in biosurgery. Facial Plast Surg. 2010 Oct;26(5):413-20 Authors: Ahn JM, Mao JJ Current autologous fat grafting technique suffers from the drawbacks of donor site morbidity and, more importantly, significant resorption of the grafted fat. Adipose tissue engineering using adult human stem cells has been found to overcome the shortcomings of autologous fat grafting in reconstructing facial defects. Mesenchymal stem cells that can self-renew and differentiate into mature adipocytes have been used to generate adipose tissue, in both in vitro and in vivo cell transplantation studies. However, long-term maintenance of the shape and dimension of the produced adipose tissue remains a challenge, even in tissue engineering with cell transplantation. The choice of appropriate scaffolds to promote stem cell adhesion, proliferation, and differentiation is essential for successful adipogenesis. Recent advances in nanotechnology allow the development of nanostructured scaffolds with a cellular environment that maximally enhances not only cell expansion but also the neovascularization that is crucial for long-term maintenance of cell volume. Cell homing is a technique that actively recruits endogenous host stem cells into a predefined anatomic location for the desired tissue generation. Bypassing ex vivo cell manipulation, the cell homing technique eliminates donor site morbidity and rejection, reducing the regulation issue in clinical translation. Mao et al. introduced the concept of biosurgery, which combined nanostructured scaffolds and growth factor biocues, with or without cell transplantation, for successful de novo adipogenesis in restoring facial defects. Important questions, such as the necessity of cell transplantation in scaling up the size of engineered adipose tissue, need to be answered with further studies. However, the era of biosurgery replacing conventional treatments such as biologically inactive filler injections and alloplastic implants appears to be in the near future. PMID: 20853233 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Embryonic progenitor cells in adipose tissue engineering. Facial Plast Surg. 2010 Oct;26(5):405-12 Authors: Hillel AT, Elisseeff JH Adipose tissue is extensively used in facial plastic surgery as a soft tissue filler for small-to-large facial defects. Variable results with autologous fat grafting and lipoinjection has led to interest in alternative forms of adipose tissue, including tissue engineered adipose tissue. Tissue engineering combines cells, scaffolds, and bioactive signals to regenerate organs or tissue. Cell sources include preadipocytes, adult stem cells, and embryonic stem cells. Although adult cells may be easily accessible from a patient, embryonic progenitor cells have comparative advantages over adult stem cells including indefinite self-renewal (high proliferative and expansion capacity) and strong tissue-forming capacity. This article will describe the types of embryonic progenitor cells and the cell culture conditions, common biomaterials, signaling factors, and biomechanical forces used in adipose tissue engineering. We will identify optimal conditions to generate functional, long-lasting adipose-like tissue. Lastly, we will propose potential future directions for the rapidly expanding field of adipose tissue engineering. PMID: 20853232 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Septal cartilage tissue engineering: new horizons. Facial Plast Surg. 2010 Oct;26(5):396-404 Authors: Greene JJ, Watson D Cartilage tissue engineering is a dynamically changing field that has the potential to address some of the tissue repair challenges seen in nasal and craniofacial reconstructive surgeries. The scope of the problem includes limited autologous tissue availability, donor site morbidity associated with the harvesting of these tissue grafts, and the risk of an immune reaction to allogenic or synthetic implants that might be used as alternatives. Current tissue engineering strategies involve harvesting a small biopsy specimen from a patient and then isolating chondrocytes through enzymatic digestion of the extracellular matrix. These isolated chondrocytes can be expanded in monolayer and reseeded into a three-dimensional scaffold that could potentially be used as autologous surgical grafts. Using cell-expansion techniques, it would be feasible to generate abundant amounts of cartilage in defined shapes and sizes. The ideal tissue-engineered cartilage would resemble native tissue in terms of its biochemical, structural, and metabolic properties so that it could restore stability, function, and contour to the damaged or defective facial region. In this article, emerging technology and major challenges are described to highlight recent advances and overall trends within septal cartilage tissue engineering. PMID: 20853231 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Clinical applications of stem cells in craniofacial surgery. Facial Plast Surg. 2010 Oct;26(5):385-95 Authors: Runyan CM, Taylor JA Few areas of translational medicine carry as much excitement and hope as stem cell therapies. Because of recent advances in material science and stem cell and developmental biology that help to target molecules and pathways to restore the body's regenerative capacity, the "engineering" of missing tissue is quickly becoming a reality. Classically, tissue engineering has been thought to require external regenerative resources including a scaffold, cells, and growth factors. The allure of providing an exact replica of a missing bone that incorporates to become indistinguishable from self, has the capacity to heal and grow, is resistant to infection, and has minimal morbidity is a "holy grail" to all surgeons who work with bone. This article attempts to shed light on the use of stem cells for craniofacial reconstruction, including important principles learned from other scientific disciplines, relevant animal models for tissue engineering, early clinical reports from our experience and that of others, and future directions. PMID: 20853230 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | The Potential of Adipose Stem Cells in Regenerative Medicine. Stem Cell Rev. 2010 Sep 18; Authors: Lindroos B, Suuronen R, Miettinen S Adipose stem cells (ASCs) are an attractive and abundant stem cell source with therapeutic applicability in diverse fields for the repair and regeneration of acute and chronically damaged tissues. Importantly, unlike the human bone marrow stromal/stem stem cells (BMSCs) that are present at low frequency in the bone marrow, ASCs can be retrieved in high number from either liposuction aspirates or subcutaneous adipose tissue fragments and can easily be expanded in vitro. ASCs display properties similar to that observed in BMSCs and, upon induction, undergo at least osteogenic, chondrogenic, adipogenic and neurogenic, differentiation in vitro. Furthermore, ASCs have been shown to be immunoprivileged, prevent severe graft-versus-host disease in vitro and in vivo and to be genetically stable in long-term culture. They have also proven applicability in other functions, such as providing hematopoietic support and gene transfer. Due to these characteristics, ASCs have rapidly advanced into clinical trials for treatment of a broad range of conditions. As cell therapies are becoming more frequent, clinical laboratories following good manufacturing practices are needed. At the same time as laboratory processes become more extensive, the need for control in the processing laboratory grows consequently involving a greater risk of complications and possibly adverse events for the recipient. Therefore, the safety, reproducibility and quality of the stem cells must thoroughly be examined prior to extensive use in clinical applications. In this review, some of the aspects of examination on ASCs in vitro and the utilization of ASCs in clinical studies are discussed. PMID: 20853072 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Three-Dimensional Quantitative Micromorphology of Pre- and Post-Implanted Engineered Heart Valve Tissues. Ann Biomed Eng. 2010 Sep 18; Authors: Eckert CE, Mikulis BT, Gottlieb D, Gerneke D, Legrice I, Padera RF, Mayer JE, Schoen FJ, Sacks MS There is a significant gap in our knowledge of engineered heart valve tissue (EHVT) development regarding detailed three-dimensional (3D) tissue formation and remodeling from the point of in vitro culturing to full in vivo function. As a step toward understanding the complexities of EHVT formation and remodeling, a novel serial confocal microscopy technique was employed to obtain 3D microstructural information of pre-implant (PRI) and post-implant for 12 weeks (POI) EHVT fabricated from PGA:PLLA scaffolds and seeded with ovine bone-marrow-derived mesenchymal stem cells. Custom scaffold fiber tracking software was developed to quantify scaffold fiber architectural features such as length, tortuosity, and minimum scaffold fiber-fiber separation distance and scaffold fiber orientation was quantified utilizing a 3D fabric tensor. In addition, collagen and cellular density of ovine pulmonary valve leaflet tissue were also analyzed for baseline comparisons. Results indicated that in the unseeded state, scaffold fibers formed a continuous, oriented network. In the PRI state, the scaffold showed some fragmentation with a scaffold volume fraction of 7.79%. In the POI specimen, the scaffold became highly fragmented, forming a randomly distributed short fibrous network (volume fraction of 2.03%) within a contiguous, dense collagenous matrix. Both PGA and PLLA scaffold fibers were observed in the PRI and POI specimens. Collagen density remained similar in both PRI and POI specimens (74.2 and 71.5%, respectively), though the distributions in the transmural direction appeared slightly more homogenous in the POI specimen. Finally, to guide future 2D histological studies for large-scale studies (since acquisition of high-resolution volumetric data is not practical for all specimens), we investigated changes in relevant collagen and scaffold metrics (collagen density and scaffold fiber orientation) with varying section spacing. It was found that a sectioning spacing up to 25 μm (for scaffold morphology) and 50 μm (for collagen density) in both PRI and POI tissues did not result in loss of information fidelity, and that sectioning in the circumferential or radial direction provides the greatest preservation of information. This is the first known work to investigate EHVT microstructure over a large volume with high resolution and to investigate time evolving in vivo EHVT morphology. The important scaffold fiber structural changes observed provide morphological information crucial for guiding future structurally based constitutive modeling efforts focused on better understanding EHVT tissue formation and remodeling. PMID: 20853027 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Microsatellite Instability Detection by High-Resolution Melting Analysis. Clin Chem. 2010 Sep 17; Authors: Janavicius R, Matiukaite D, Jakubauskas A, Griskevicius L BACKGROUND: Microsatellite instability (MSI) is an important marker for screening for hereditary nonpolyposis colorectal cancer (Lynch syndrome) as well as a prognostic and predictive marker for sporadic colorectal cancer (CRC). The mononucleotide microsatellite marker panel is a well-established and superior alternative to the traditional Bethesda MSI analysis panel, and does not require testing for corresponding normal DNA. The most common MSI detection techniques-fluorescent capillary electrophoresis and denaturing HPLC (DHPLC)-both have advantages and drawbacks. A new high-resolution melting (HRM) analysis method enables rapid identification of heteroduplexes in amplicons by their lower thermal stability, a technique that overcomes the main shortcomings of capillary electrophoresis and DHPLC. METHODS: We investigated the straightforward application of HRM for the detection of MSI in 70 archival CRC samples. HRM analysis for 2 MSI markers (BAT25 and BAT26) was evaluated, and 2 different HRM-enabled instruments were compared-the LightCycler® 480 (Roche Diagnostics) and the LightScanner(TM) (Idaho Technology). We also determined the analytical sensitivity and specificity of the HRM assay on both instruments using 11 known MSI-positive and 54 microsatellite-stable CRC samples. RESULTS: All MSI-positive samples were detected on both instruments (100% analytical sensitivity). The LightScanner performed better for analytical specificity, giving a combined specificity value of 99.1% compared with 92.3% on the LightCycler 480. CONCLUSIONS: We expanded the application of the HRM analysis method as an effective MSI detection technique for clinical samples. PMID: 20852132 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Activation of host tissue trophic factors through JAK/STAT3 signaling: A mechanism of mesenchymal stem cell-mediated cardiac repair. Am J Physiol Heart Circ Physiol. 2010 Sep 17; Authors: Shabbir A, Zisa D, Lin H, Mastri M, Roloff G, Suzuki G, Lee T We recently demonstrated a cardiac therapeutic regimen based on injection of bone marrow mesenchymal stem cells (MSCs) into the skeletal muscle. Although the injected MSCs were trapped in the local musculature, the extracardiac cell delivery approach repaired the failing hamster heart. This finding uncovers a tissue repair mechanism mediated by trophic factors derived from the injected MSCs and local musculature that can be explored for minimally invasive stem cell therapy. However, the trophic factors involved in cardiac repair and their actions remain largely undefined. We demonstrate here a role of MSC-derived IL-6-type cytokines in cardiac repair through engagement of the skeletal muscle JAK/STAT3 axis. The MSC IL-6-type cytokines activated JAK/STAT3 signaling in cultured C2C12 skeletal myocytes and caused increased expression of the STAT3 target genes HGF and VEGF, which was inhibited by gp130 blockade. These in vitro findings were corroborated by in vivo studies, showing that the MSC-injected hamstrings exhibited activated JAK/STAT3 signaling and increased growth factor/cytokine production. Elevated host tissue growth factor levels were also detected in quadriceps, liver, and brain, suggesting a possible global trophic effect. Paracrine actions of these host tissue-derived factors activated the endogenous cardiac repair mechanisms in the diseased heart mediated by AKT, ERK, and JAK/STAT3. Administration of the cell-permeable JAK/STAT inhibitor WP1066 abrogated MSC-mediated host tissue growth factor expression and functional improvement. The study illustrates that the host tissue trophic factor network can be activated by MSC-mediated JAK/STAT3 signaling for tissue repair. PMID: 20852053 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Tissue engineered biological augmentation for tendon healing: a systematic review. Br Med Bull. 2010 Sep 17; Authors: Longo UG, Lamberti A, Maffulli N, Denaro V Tendon injuries give rise to significant morbidity. In the last few decades, several techniques have been increasingly used to optimize tendon healing. We performed a comprehensive search of PubMed, Medline, Cochrane, CINAHL and Embase databases using various combinations of the commercial names of each scaffold and the keywords 'tendon', 'rotator cuff', 'supraspinatus tendon', 'Achilles tendon', 'growth factors', 'cytokines', 'gene therapy', 'tissue engineering', 'mesenchymal' and 'stem cells' over the years 1966-2009. All articles relevant to the subject were retrieved, and their bibliographies were hand searched for further references in the context to tissue-engineered biological augmentation for tendon healing. Several new techniques are available for tissue-engineered biological augmentation for tendon healing, growth factors, gene therapy and mesenchimal stem cells. Data are lacking to allow definitive conclusions on the use of these techniques for routine management of tendon ailments. The emerging field of tissue engineering holds the promise to use new techniques for tendon augmentation and repair. Preliminary studies support the idea that these techniques can provide an alternative for tendon augmentation with great therapeutic potential. The optimization strategies discussed in this article are currently at an early stage of development. Although these emerging technologies may develop into substantial clinical treatment options, their full impact needs to be critically evaluated in a scientific fashion. PMID: 20851817 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | G-CSF for Stem Cell Therapy in Acute Myocardial Infarction: Friend or Foe? Cardiovasc Res. 2010 Sep 17; Authors: Shim W, Mehta A, Lim SY, Zhang G, Lim CH, Chua T, Wong P Stem cell-based therapy has emerged as a potential therapeutic option for patients with acute myocardial infarction (AMI). The ability of granulocyte colony stimulating factor (G-CSF) to mobilize endogenous stem cells as well as to protect cardiomyocytes at risk via paracrine effects has attracted considerable attention. In the past decade, a number of clinical trials were carried out to study the efficacy of G-CSF in cardiac repair. These trials showed variable outcomes in terms of improved cardiac contractile function and suppressed left ventricular negative remodeling. Critical examinations of these results have raised doubts on the effectiveness of G-CSF in modulating functional recovery. However, these cumulative clinical experiences are helpful in the understanding of mechanisms and roles of signaling pathways in regulating homing and engraftment of bone marrow stem cells (BMSCs) to infarcted heart. In this review, we discuss some of the observations that may have influenced the clinical outcomes. Improving strategies that target the critical aspects of G-CSF driven cardiac therapy may provide a better platform to augment clinical benefits in future trials. PMID: 20851808 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Increased mechanosensitivity of cells cultured on nanotopographies. J Biomech. 2010 Sep 17; Authors: Salvi JD, Yul Lim J, Donahue HJ Enhancing cellular mechanosensitivity is recognized as a novel tool for successful musculoskeletal tissue engineering. We examined the hypothesis that mechanosensitivity of human mesenchymal stem cells (hMSCs) is enhanced on nanotopographic substrates relative to flat surfaces. hMSCs were cultured on polymer-demixed, randomly distributed nanoisland surfaces with varying island heights and changes in intracellular calcium concentration, [Ca(2+)](i), in response to fluid flow induced shear stress were quantifide. Stem cells cultured on specific scale nanotopographies displayed greater intracellular calcium responses to fluid flow. hMSCs cultured on 10-20nm high nanoislands displayed a greater percentage of cells responding in calcium relative to cells cultured on flat control, and showed greater average [Ca(2+)](i) increase relative to cells cultured on other nanoislands (45-80nm high nanoislands). As [Ca(2+)](i) is an important regulator of downstream signaling, as well as proliferation and differentiation of hMSCs, this observation suggests that specific scale nanotopographies provide an optimal milieu for promoting stem cell mechanotransduction activity. That mechanical signals and substrate nanotopography may synergistically regulate cell behavior is of significant interest in the development of regenerative medicine protocols. PMID: 20851397 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Development of an Acellular Bioengineered Matrix with a Dominant Vascular Pedicle. J Surg Res. 2010 Aug 6; Authors: Henderson PW, Nagineni VV, Harper A, Bavinck N, Sohn AM, Krijgh DD, Jimenez N, Weinstein AL, Spector JA BACKGROUND: This study assessed the feasibility of creating a tissue engineering platform by decellularization of fasciocutaneous tissue. MATERIALS AND METHODS: A fasciocutaneous flap based upon the superficial inferior epigastric artery was harvested from the abdominal wall of 8-wk-old male Sprague-Dawley rats. All cellular components were removed by sequential treatment with sodium azide, DNAse, and sodium deoxycholate. The degree of decellularization was qualitatively assessed by histology and quantitatively assessed by spectrophotometry. Persistence of relevant extracellular matrix proteins was shown following staining with orcein and hematoxylin. The duration of circuit patency was determined by continuous perfusion with a peristaltic perfusion pump. RESULTS: Gross and histologic examination demonstrated removal of cellular constituents with preservation of tissue matrix architecture, including macrochannels and microchannels. This was confirmed by the application of spectrophotometry to DNA isolates, which showed that the decellularized flap retained 4.04 ng/μL DNA, compared with the non-processed control, which retained 37.03 ng/μL DNA, and the acellular control, which was read as having 0.65 ng/μL DNA. The extracellular matrix of vessel walls was shown to remain intact. Peristaltic perfusion of the cannulated pedicle inflow channel with phosphate buffered saline at a rate of 200 μL/min confirmed circuit patency for 6 h. CONCLUSION: Fasciocutaneous flaps harvested with an intact vascular pedicle and associated tissue vascular network can be successfully decellularized and perfused ex vivo. This methodology, which is scalable to human size tissues, provides promise as a technique for the production of customizable engineered tissues. PMID: 20850792 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Dystrophin-deficient zebrafish feature aspects of the Duchenne muscular dystrophy pathology. Neuromuscul Disord. 2010 Sep 15; Authors: Berger J, Berger S, Hall TE, Lieschke GJ, Currie PD Duchenne muscular dystrophy is caused by mutations in the dystrophin gene. As in humans, zebrafish dystrophin is initially expressed at the peripheral ends of the myofibres adjacent to the myotendinous junction and gradually shifts to non-junctional sites. Dystrophin-deficient zebrafish larvae are characterised by abundant necrotic fibres being replaced by mono-nucleated infiltrates, extensive fibrosis accompanied by inflammation, and a broader variation in muscle fibre cross-sectional areas. Muscle progenitor proliferation cannot compensate for the extensive skeletal muscle loss. Live imaging of dystrophin-deficient zebrafish larvae documents detaching myofibres elicited by muscle contraction. Correspondingly, the progressive phenotype of dystrophin-deficient zebrafish resembles many aspects of the human disease, suggesting that specific advantages of the zebrafish model system, such as the ability to undertake in vivo drug screens and real time analysis of muscle fibre loss, could be used to make novel insights relevant to understanding and treating the pathological basis of dystrophin-deficient muscular dystrophy. PMID: 20850317 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A neurospheroid network-stamping method for neural transplantation to the brain. Biomaterials. 2010 Sep 15; Authors: Kato-Negishi M, Tsuda Y, Onoe H, Takeuchi S Neural transplantation therapy using neural stem cells has received as potential treatments for neurodegenerative diseases. Indeed, this therapy is thought to be effective for replacement of degenerating neurons in restricted anatomical region. However, because injected neural stem cells integrate randomly into the host neural network, another approach is needed to establish a neural pathway between selective areas of the brain or treat widespread degeneration across multiple brain regions. One of the promising approaches might be a therapy using pre-made neural network in vitro by the tissue engineering technique. In this study, we engineered a three-dimensional (3D) tissue with a neuronal network that can be easily manipulated and transplanted onto the host brain tissue in vivo. A polydimethylsiloxane microchamber array facilitated the formation of multiple neurospheroids, which in turn interconnected via neuronal processes to form a centimeter-sized neurospheroid network (NSN). The NSN was transferable onto the cortical surface of the brain without damage of the neuronal network. After transfer onto the cortical tissue, the NSN showed neural activity for more than 8 days. Moreover, neurons of the transplanted NSN extended their axons into the host cortical tissue and established synaptic connections with host neurons. Our findings suggest that this method could lay the foundation for treating severe degenerative brain disease. PMID: 20850180 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Long-term in vitro degradation of PDLLA/Bioglass® bone scaffolds in acellular simulated body fluid. Acta Biomater. 2010 Sep 14; Authors: Blaker JJ, Nazhat SN, Maquet V, Boccaccini AR The long-term (600 days) in vitro degradation of highly porous PDLLA/Bioglass®-filled composite foams developed for bone tissue engineering scaffolds has been investigated in simulated body fluid (SBF). Foams of circa 93% porosity were produced by thermally induced phase separation (TIPS). The degradation profile for foams of neat PDLLA and the influence of Bioglass® addition were comprehensively assessed in terms of changes in dimensional stability, pore morphology, weight loss, molecular weight and mechanical properties (dry and wet states). It is shown that the degradation process proceeded in several stages: a) the quasi-stable stage, where water absorption and plasticization occur together with weight loss due to Bioglass® particle loss and dissolution, resulting in decreased wet mechanical properties, b) a stage of slight increase in the wet mechanical properties and moderate decrease in dimensions, with properties remaining moderately constant until the onset of significant weight loss, whilst molecular weight continues to decrease, and c) an end-stage of massive weight loss, disruption of pore structure and the formation of blisters and embrittlement of the scaffold (evident on handling). The findings from this long-term in vitro degradation investigation underpin studies that have been and continue to be performed on highly porous bioactive glass filled poly(α-hydroxyesters) for bone tissue engineering applications. PMID: 20849987 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Through-thickness control of polymer bioresorption via electron beam irradiation. Acta Biomater. 2010 Sep 14; Authors: Cairns ML, Sykes A, Dickson GR, Orr JF, Farrar D, Dumba A, Buchanan FJ Predicable and controlled degradation is not only central to the accurate delivery of bioactive agents and drugs, it also plays a vital role in key aspects of bone tissue engineering. The work addressed in this paper investigates the utilization of e-beam irradiation in order to achieve a controlled (surface) degradation profile. This study focuses on the modification of commercially and clinically relevant materials, namely PLLA, PLLA-HA PLG, and PLDL. Samples were subjected to irradiation treatments using a 0.5 MeV electron beam with delivered surface doses of 150 kGy and 500 kGy. In addition, an acrylic attenuation shield was used for selected samples to control the penetration of the e-beam. E-beam irradiation induced chain scission in all polymers as characterized by reduced molecular weights and glass transition temperatures (Tg). Irradiation not only produced changes in the physical properties of the polymers but also had associated effects on the surface erosion of the materials during hydrolytic degradation. Moreover, the extent to which both mechanical and hydrolytic degradation was observed is synonymous with the estimated penetration of the beam (as controlled by the employment of an attenuation shield). PMID: 20849986 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Biomimetic composite coating on rapid prototyped scaffolds for bone tissue engineering. Acta Biomater. 2010 Sep 14; Authors: Arafat MT, Lam CX, Ekaputra AK, Wong SY, Li X, Gibson I The objective of this present study is to improve functional performance of rapid prototyped scaffolds for bone tissue engineering through biomimetic composite coating. Rapid prototyped poly(ε-caprolactone)/tri-calcium phosphate (PCL/TCP) scaffolds were fabricated using screw extrusion system (SES). The fabricated PCL/TCP scaffolds were coated with carbonated hydroxyapatite (CHA)-gelatin composite via biomimetic co-precipitation. The structure of the prepared CHA-gelatin composite coating was studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Compressive mechanical testing revealed that coating process did not have any detrimental effect on the mechanical property of the scaffolds. The cell-scaffold interaction was studied by culturing porcine bone marrow stromal cells (BMSCs) on the scaffolds, and assessing proliferation, bone related gene and protein expression capabilities of BMSCs. Confocal laser microscopy and SEM images of the cell-scaffold constructs showed uniform distribution of cell-sheet and accumulation of extracellular matrix at the interior of CHA-gelatin composite coated PCL/TCP scaffolds. The proliferation rate of BMSCs on CHA-gelatin composite coated PCL/TCP scaffolds was about 2.3 times and 1.7 times higher than that on the PCL/TCP scaffolds and CHA coated PCL/TCP scaffolds, respectively, by day 10. Furthermore, reverse transcription polymerase chain reaction and western blot analysis revealed that CHA-gelatin composite coated PCL/TCP scaffolds stimulate osteogenic differentiation of BMSCs the most, compared to PCL/TCP scaffolds and CHA coated PCL/TCP scaffolds. These results demonstrate that CHA-gelatin composite coated rapid prototyped PCL/TCP scaffolds are promising for bone tissue engineering. PMID: 20849985 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Aligned natural-synthetic polyblend nanofibers for peripheral nerve regeneration. Acta Biomater. 2010 Sep 14; Authors: Wang CY, Zhang KH, Fan CY, Mo XM, Ruan HJ, Li FF Peripheral nerve regeneration remains a significant clinical challenge to researchers. Progress in the design of tissue engineering scaffolds provides an alternative approach for neural regeneration. In this study, aligned silk fibroin (SF) blended poly(L-lactic acid-co-ε-caprolactone) [P(LLA-CL)] nanofibrous scaffolds were fabricated via electrospinning methods, and then reeled into aligned nerve guidance conduit (NGC) for promoting nerve regeneration. The aligned SF/P(LLA-CL) NGC was used as a bridge implanting across a 10 mm defect of sciatic nerve in rats, and the outcome of regenerated nerve at 4 and 8 weeks was evaluated by a combination of electrophysiological assessment, histological and immunohistological analysis, as well as electron microscopy. The electrophysiological examination showed that the functional recovery of regenerated nerve in the SF/P(LLA-CL) NGC group was superior to that in the P(LLA-CL) NGC group. The morphological analysis also indicated that the regenerated nerve in SF/P(LLA-CL) NGC was more mature. All the results demonstrated that the aligned SF/P(LLA-CL) NGC could greatly promote peripheral nerve regeneration in comparison with the aligned P(LLA-CL) NGC, thus raising a potential application in nerve regeneration. PMID: 20849984 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Comparative study of the chondrogenic potential of human bone marrow stromal cells, neonatal chondrocytes and adult chondrocytes. Biochem Biophys Res Commun. 2010 Sep 14; Authors: Saha S, Kirkham J, Wood D, Curran S, Yang X Cartilage tissue engineering is still a major clinical challenge with optimization of a suitable source of cells for cartilage repair/regeneration not yet fully addressed. The aims of this study were to compare and contrast the differences in chondrogenic behaviour between human bone marrow stromal cells (HBMSCs), human neonatal and adult chondrocytes to further our understanding of chondroinduction relative to cell maturity and to identify factors that promote chondrogenesis and maintain functional homeostasis. Cells were cultured in monolayer in either chondrogenic or basal medium, recapitulating procedures used in existing clinical procedures for cell based therapies. Cell doubling time, morphology and alkaline phosphatase specific activity (ALPSA) were determined at different time points. Expression of chondrogenic markers (SOX9, ACAN and COL2A1) was compared via real time polymerase chain reaction. Amongst the three cell types studied, HBMSCs had the highest ALPSA in basal culture and lowest ALPSA in chondrogenic media. Neonatal chondrocytes were the most proliferative and adult chondrocytes had the lowest ALPSA in basal media. Gene expression analysis revealed a difference in the temporal expression of chondrogenic markers which were up regulated in chondrogenic medium compared to levels in basal medium. Of the three cell types studied, adult chondrocytes offer a more promising cell source for cartilage tissue engineering. This comparative study revealed differences between the microenvironment of all three cell types and provides useful information to inform cell-based therapies for cartilage regeneration. PMID: 20849819 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Isolation of cell-free bacterial inclusion bodies. Microb Cell Fact. 2010 Sep 17;9(1):71 Authors: Rodriguez-Carmona E, Cano-Garrido O, Seras-Franzoso J, Villaverde A, Garcia-Fruitos E ABSTRACT: BACKGROUND: Bacterial inclusion bodies are submicron protein clusters usually found in recombinant bacteria that have been traditionally considered as undesirable products from protein production processes. However, being fully biocompatible, they have been recently characterized as nanoparticulate inert materials useful as scaffolds for tissue engineering, with potentially wider applicability in biomedicine and material sciences. Current protocols for inclusion body isolation from Escherichia coli usually offer between 95 to 99 % of protein recovery, what in practical terms, might imply extensive bacterial cell contamination, not compatible with the use of inclusion bodies in biological interfaces. RESULTS: Using an appropriate combination of chemical and mechanical cell disruption methods we have established a convenient procedure for the recovery of bacterial inclusion bodies with undetectable levels of viable cell contamination, below 10-1 cfu/ml, keeping the particulate organization of these aggregates regarding size and protein folding features. CONCLUSIONS: The application of the developed protocol allows obtaining bacterial free inclusion bodies suitable for use in mammalian cell cultures and other biological interfaces. PMID: 20849629 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Mid term resultas after bone marrow laser revascularization for treating refractory angina. BMC Cardiovasc Disord. 2010 Sep 17;10(1):42 Authors: Reyes G, Allen K, Alvarez P, Alegre A, Aguado B, Oliveras M, Caballero P, Rodriguez J, Duarte J ABSTRACT: BACKGROUND: To evaluate the midterm results of patients with angina and diffuse coronary artery disease treated with transmyocardial revascularization in combination with autologous stem cell therapy. METHODS: Nineteen patients with diffuse coronary artery disease and medically refractory class III/IV angina were evaluated between June 2007 and December 2009 for sole therapy TMR combined with intramyocardial injection of concentrated stem cells. At the time of surgery, autologous bone marrow (120cc) was aspirated from the iliac crest. A cardiac MRI and an isotopic test were performed before and after the procedure. Follow-up was performed by personal interview. RESULTS: There were no perioperative adverse events including no arrhythmias. Mean number of laser channels was 20 and the mean total number of intramyocardially injected cells per milliliter were: total mononuclear cells(83.6 x 106), CD34+ cells(0.6 x 106), and CD133+ cells(0.34 x 106). At 12 months mean follow-up average angina class was significantly improved (3.4 +/- 0.5 vs 1.4 +/- 0.6; p=0.004). In addition, monthly cardiovascular medication usage was significantly decreased (348+/-118 vs. 201+/-92; p=0.001). At six months follow up there was a reduction in the number of cardiac hospital readmissions (2.9+/-2.3 vs. 0.5+/-0.8; p<0.001). MRI showed no alterations regarding LV volumes and a 3% improvement regarding ejection fraction. CONCLUSIONS: The stem cell isolator efficiently concentrated autologous bone marrow derived stem cells while the TMR/stem cell combination delivery device worked uneventfully. An improvement in clinical status was noticed in the midterm follow-up. Images test showed no morphological alterations in the left ventricle after the procedure. PMID: 20849586 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Gelatin-Based Laser Direct-Write Technique for the Precise Spatial Patterning of Cells. Tissue Eng Part C Methods. 2010 Sep 20; Authors: Schiele NR, Chrisey DB, Corr DT Laser direct-writing provides a method to pattern living cells in vitro, to study various cell-cell interactions, and build cellular constructs. However, the materials typically used may limit its long-term application. By utilizing gelatin coatings on the print ribbon and growth surface, we developed a new approach for laser cell printing that overcomes the limitations of Matrigelâ„¢. Gelatin is free of growth factors and extraneous matrix components that may interfere with cellular processes under investigation. Gelatin-based laser direct-write was able to successfully pattern human dermal fibroblasts with high post-transfer viability (91% ± 3%) and no observed double strand DNA damage. As seen with atomic force microscopy, gelatin offers a unique benefit in that it is present temporarily to allow cell transfer, but melts and is removed with incubation to reveal the desired application-specific growth surface. This provides unobstructed cellular growth after printing. Monitoring cell location following transfer, we show that melting and removal of gelatin does not affect cellular placement; cells maintained registry within 5.6 μm ± 2.5 μm to the initial pattern. This study demonstrates the effectiveness of gelatin in laser direct-writing to create spatially-precise cell patterns with the potential for applications in tissue engineering, stem cell, and cancer research. PMID: 20849381 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Gene profiling of bone marrow- and adipose tissue-derived stromal cells: a key role of Kruppel-like factor 4 in cell fate regulation. Cytotherapy. 2010 Sep 20; Authors: Saulnier N, Puglisi MA, Lattanzi W, Castellini L, Pani G, Leone G, Alfieri S, Michetti F, Piscaglia AC, Gasbarrini A Abstract Background aims. Bone marrow- and adipose tissue-derived mesenchymal stromal cells (MSC) represent promising sources for regenerative medicine. However, the precise molecular mechanisms underlying MSC stemness maintenance versus differentiation are not fully understood. The aim of this study was to compare the genome-wide expression profiles of bone marrow- and adipose tissue-derived MSC, in order to identify a common molecular stemness core. Methods. Molecular profiling was carried out using Affymetrix microarray and relevant genes were further validated by Q-PCR. Results. We identified an overlapping dataset of 190 transcripts commonly regulated in both cell populations, which included several genes involved in stemness regulation (i.e. self-renewal potential and the ability to generate differentiated cells), various signaling pathways and transcription factors. In particular, we identified a central role of the Kruppel-like factor 4 (KLF4) DNA-binding protein in regulating MSC transcriptional activity. Conclusions. Our results provide new insights toward understanding the molecular basis of MSC stemness maintenance and underline the ability of KLF4 to maintain cells in an undifferentiated state. PMID: 20849362 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Polyhydroxybutyrate and its Copolymer with Polyhydroxyvalerate as Biomaterials: Influence on Progression of Stem Cell Cycle. Biomacromolecules. 2010 Sep 17; Authors: Ahmed T, Marçal H, Lawless M, Wanandy NS, Chiu A, Foster LJ Poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) are biopolyesters reported to provide favorable microenvironments for cell culture and possess potential for tissue engineering applications. Both biopolymers have been investigated for applications in a variety of medical scenarios, including nerve and bone repair. This study investigated the influence these biomaterials exerted on cell cycle progression of olfactory ensheathing cells (OECs) and mesenchymal stem cells (MSCs) commonly used in the engineering of nerve and bone tissues. Cell cycle regulation is important for cell survival; analysis revealed that the biomaterials induced significant cell cycle progression in both MSCs and OECs. Significantly higher percentages of cells were cycled at synthesis (S) phase of the cycle on PHBV films compared to PHB, with MSCs more susceptible than OECs. Furthermore, detection of early stages of apoptotic activation showed significant differences in the two cell populations exhibiting necrosis and apoptosis when cultivated on the biomaterials. OECs compromised on PHB (5.6%) and PHBV (2.5%) compared to MSCs with 12.6% on PHB and 17% on PHBV. Significant differences in crystallinity and surface rugosity were determined between films of the two biomaterials, 88% and 1.12 μm for PHB and 76% and 0.72 μm for PHBV. While changes in surface properties may have influenced cell adhesion, the work presented here suggests that application of these biomaterials in tissue engineering are specific to cell type and requires a detailed investigation at the cell-material interface. PMID: 20849100 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Composite cell sheets: a further step toward safe and effective myocardial regeneration by cardiac progenitors derived from embryonic stem cells. Circulation. 2010 Sep 14;122(11 Suppl):S118-23 Authors: Bel A, Planat-Bernard V, Saito A, Bonnevie L, Bellamy V, Sabbah L, Bellabas L, Brinon B, Vanneaux V, Pradeau P, Peyrard S, Larghero J, Pouly J, Binder P, Garcia S, Shimizu T, Sawa Y, Okano T, Bruneval P, Desnos M, Hagège AA, Casteilla L, Pucéat M, Menasché P BACKGROUND: The safety and efficacy of myocardial regeneration using embryonic stem cells are limited by the risk of teratoma and the high rate of cell death. METHODS AND RESULTS: To address these issues, we developed a composite construct made of a sheet of adipose tissue-derived stroma cells and embryonic stem cell-derived cardiac progenitors. Ten Rhesus monkeys underwent a transient coronary artery occlusion followed, 2 weeks later, by the open-chest delivery of the composite cell sheet over the infarcted area or a sham operation. The sheet was made of adipose tissue-derived stroma cells grown from a biopsy of autologous adipose tissue and cultured onto temperature-responsive dishes. Allogeneic Rhesus embryonic stem cells were committed to a cardiac lineage and immunomagnetically sorted to yield SSEA-1(+) cardiac progenitors, which were then deposited onto the cell sheet. Cyclosporine was given for 2 months until the animals were euthanized. Preimplantation studies showed that the SSEA-1(+) progenitors expressed cardiac markers and had lost pluripotency. After 2 months, there was no teratoma in any of the 5 cell-treated monkeys. Analysis of >1500 histological sections showed that the SSEA-1(+) cardiac progenitors had differentiated into cardiomyocytes, as evidenced by immunofluorescence and real-time polymerase chain reaction. There were also a robust engraftment of autologous adipose tissue-derived stroma cells and increased angiogenesis compared with the sham animals. CONCLUSIONS: These data collected in a clinically relevant nonhuman primate model show that developmentally restricted SSEA-1(+) cardiac progenitors appear to be safe and highlight the benefit of the epicardial delivery of a construct harboring cells with a cardiomyogenic differentiation potential and cells providing them the necessary trophic support. PMID: 20837902 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Anti-CD47 antibody synergizes with rituximab to promote phagocytosis and eradicate non-Hodgkin lymphoma. Cell. 2010 Sep 3;142(5):699-713 Authors: Chao MP, Alizadeh AA, Tang C, Myklebust JH, Varghese B, Gill S, Jan M, Cha AC, Chan CK, Tan BT, Park CY, Zhao F, Kohrt HE, Malumbres R, Briones J, Gascoyne RD, Lossos IS, Levy R, Weissman IL, Majeti R Monoclonal antibodies are standard therapeutics for several cancers including the anti-CD20 antibody rituximab for B cell non-Hodgkin lymphoma (NHL). Rituximab and other antibodies are not curative and must be combined with cytotoxic chemotherapy for clinical benefit. Here we report the eradication of human NHL solely with a monoclonal antibody therapy combining rituximab with a blocking anti-CD47 antibody. We identified increased expression of CD47 on human NHL cells and determined that higher CD47 expression independently predicted adverse clinical outcomes in multiple NHL subtypes. Blocking anti-CD47 antibodies preferentially enabled phagocytosis of NHL cells and synergized with rituximab. Treatment of human NHL-engrafted mice with anti-CD47 antibody reduced lymphoma burden and improved survival, while combination treatment with rituximab led to elimination of lymphoma and cure. These antibodies synergized through a mechanism combining Fc receptor (FcR)-dependent and FcR-independent stimulation of phagocytosis that might be applicable to many other cancers. PMID: 20813259 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Bioprinting vessel-like constructs using hyaluronan hydrogels crosslinked with tetrahedral polyethylene glycol tetracrylates. Biomaterials. 2010 Aug;31(24):6173-81 Authors: Skardal A, Zhang J, Prestwich GD Bioprinting enables deposition of cells and biomaterials into spatial orientations and complexities that mirror physiologically relevant geometries. To facilitate the development of bioartificial vessel-like grafts, two four-armed polyethylene glycol (PEG) derivatives with different PEG chain lengths, TetraPEG8 and TetraPEG13, were synthesized from tetrahedral pentaerythritol derivatives. The TetraPEGs are unique multi-armed PEGs with a compact and symmetrical core. The TetraPEGs were converted to tetra-acrylate derivatives (TetraPAcs) which were used in turn to co-crosslink thiolated hyaluronic acid and gelatin derivatives into extrudable hydrogels for printing tissue constructs. First, the hydrogels produced by TetraPAc crosslinking showed significantly higher shear storage moduli when compared to PEG diacrylate (PEGDA)-crosslinked synthetic extracellular matrices (sECMs) of similar composition. These stiffer hydrogels have rheological properties more suited to bioprinting high-density cell suspensions. Second, TetraPAc-crosslinked sECMs were equivalent or superior to PEGDA-crosslinked gels in supporting cell growth and proliferation. Third, the TetraPac sECMs were employed in a proof-of-concept experiment by encapsulation of NIH 3T3 cells in sausage-like hydrogel macrofilaments. These macrofilaments were then printed into tubular tissue constructs by layer-by-layer deposition using the Fab@Home printing system. LIVE/DEAD viability/cytotoxicity-stained cross-sectional images showed the bioprinted cell structures to be viable in culture for up to 4 weeks with little evidence of cell death. Thus, biofabrication of cell suspensions in TetraPAc sECMs demonstrates the feasibility of building bioartificial blood vessel-like constructs for research and potentially clinical uses. PMID: 20546891 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Isolation, differentiation and characterization of vascular cells derived from human embryonic stem cells. Nat Protoc. 2010;5(6):1115-26 Authors: Levenberg S, Ferreira LS, Chen-Konak L, Kraehenbuehl TP, Langer R Herein, we describe a protocol for the isolation of human embryonic stem cells (hESCs)-derived vascular cells at various stages of development. The cells are isolated from 10 to 15-d-old human embryoid bodies (EBs) cultured in suspension. After dissociation, cells are labeled with anti-CD34 or anti-CD31 (PECAM1) antibody and separated from the cell mixture by magnetic-activated cell separation (MACS) or fluorescent-activated cell sorting (FACS). Isolated vascular cells are then cultured in media conditions that support specific differentiation and expansion pathways. The resulting vascular cell populations contain >80% endothelial-like or smooth muscle-like cells. Assuming typical initial cell adhesion and proliferation rates, the entire procedure can be completed within 1.5 months. Vascular cells isolated and differentiated under the described conditions may constitute a potential cell source for therapeutic application toward repair of ischemic tissues, preparation of tissue-engineered vascular grafts and design of cellular kits for drug screening applications. PMID: 20539287 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of mechanical factors on the function of engineered human blood microvessels in microfluidic collagen gels. Biomaterials. 2010 Aug;31(24):6182-9 Authors: Price GM, Wong KH, Truslow JG, Leung AD, Acharya C, Tien J This work examines how mechanical signals affect the barrier function and stability of engineered human microvessels in microfluidic type I collagen gels. Constructs that were exposed to chronic low flow displayed high permeabilities to bovine serum albumin and 10 kDa dextran, numerous focal leaks, low size selectivity, and short lifespan of less than one week. Higher flows promoted barrier function and increased longevity; at the highest flows, the barrier function rivaled that observed in vivo, and all vessels survived to day 14. By studying the physiology of microvessels of different geometries, we established that shear stress and transmural pressure were the dominant mechanical signals that regulated barrier function and vascular stability, respectively. In microvessels that were exposed to high flow, elevation of intracellular cyclic AMP further increased the selectivity of the barrier and strongly suppressed cell proliferation. Computational models that incorporated stress dependence successfully predicted vascular phenotype. Our results indicate that the mechanical microenvironment plays a major role in the functionality and stability of engineered human microvessels in microfluidic collagen gels. PMID: 20537705 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | A strategy for fabrication of a three-dimensional tissue construct containing uniformly distributed embryoid body-derived cells as a cardiac patch. Biomaterials. 2010 Aug;31(24):6218-27 Authors: Huang CC, Liao CK, Yang MJ, Chen CH, Hwang SM, Hung YW, Chang Y, Sung HW Growing three-dimensional (3D) scaffolds that contain more than a few layers of seeded cells in vitro is crucial for the creation of thick and viable cardiac tissues in vivo. Embryonic stem cells (ESCs) have been used as an alternative cell source for cardiac repair; however, dissociated ESCs show poor viability in the scaffold and do not form the embryoid body (EB)-like structures. In this study, a strategy intended for cultivating EB-derived cells (EBDCs) uniformly in a porous 3D tissue scaffold was developed. This strategy employed techniques of formation of spherically symmetric EBs in a thermo-responsive hydrogel system, production of cell sheets of EBDCs in a similar hydrogel system coated with collagen and fabrication of sliced porous tissue scaffolds. The prepared EBs were collected and plated evenly in the cell-sheet culture system. After 8 days in culture, a continuous sheet of EBDCs with cell beating was obtained; our qPCR and flow cytometric analyses showed that the collagen-coated on the cell-sheet culture system can significantly enhance the population of cardiac-lineage cells. The produced EBDC sheets were then sandwiched into the sliced porous tissue scaffold. After reculture, the seeded EBDCs were redistributed uniformly throughout the scaffold, with a significant increase in mechanical strength. Cardiac-specific myosin heavy chain and alpha-actinin were expressed for some cells grown in the scaffold, while connexin 43 was clearly expressed at the cell borders. Additional studies such as employing purification techniques to enrich the population of cardiomyocytes are needed to further improve the developed tissue constructs as a bioengineered cardiac patch. PMID: 20537702 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | The dependence of MG63 osteoblast responses to (meth)acrylate-based networks on chemical structure and stiffness. Biomaterials. 2010 Aug;31(24):6131-41 Authors: Smith KE, Hyzy SL, Sunwoo M, Gall KA, Schwartz Z, Boyan BD The cell response to an implant is regulated by the implant's surface properties including topography and chemistry, but less is known about how the mechanical properties affect cell behavior. The objective of this study was to evaluate how the surface stiffness and chemistry of acrylate-based copolymer networks affect the in vitro response of human MG63 pre-osteoblast cells. Networks comprised of poly(ethylene glycol) dimethacrylate (PEGDMA; Mn approximately 750) and diethylene glycol dimethacrylate (DEGDMA) were photopolymerized at different concentrations to produce three compositions with moduli ranging from 850 to 60 MPa. To further decouple chemistry and stiffness, three networks comprised of 2-hydroxyethyl methacrylate (2HEMA) and PEGDMA or DEGDMA were also designed that exhibited a range of moduli similar to the PEGDMA-DEGDMA networks. MG63 cells were cultured on each surface and tissue culture polystyrene (TCPS), and the effect of copolymer composition on cell number, osteogenic markers (alkaline phosphatase specific activity and osteocalcin), and local growth factor production (OPG, TGF-beta1, and VEGF-A) were assessed. Cells exhibited a more differentiated phenotype on the PEGDMA-DEGDMA copolymers compared to the 2HEMA-PEGDMA copolymers. On the PEGDMA-DEGDMA system, cells exhibited a more differentiated phenotype on the stiffest surface indicated by elevated osteocalcin compared with TCPS. Conversely, cells on 2HEMA-PEGDMA copolymers became more differentiated on the less stiff 2HEMA surface. Growth factors were regulated in a differential manner. These results indicate that copolymer chemistry is the primary regulator of osteoblast differentiation, and the effect of stiffness is secondary to the surface chemistry. PMID: 20510445 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Neurobiology of injury to the developing brain. Nat Rev Neurol. 2010 Jun;6(6):328-36 Authors: Deng W Owing to improved survival rates of premature newborns, the number of very low birth weight infants is rising. Preterm infants display a greater propensity for brain injury caused by hypoxic or ischemic events, infection and/or inflammation that results in prominent white matter injury (WMI) than infants carried to full term. The intrinsic vulnerability of developing oligodendroglia to excitotoxic, oxidative and inflammatory forms of injury is a major factor in the pathogenesis of this condition. Furthermore, activated microglia and astrogliosis are critically involved in triggering WMI. Currently, no specific treatment is available for this kind of injury. Injury to the premature brain can substantially influence brain development and lead to disability. Impairment of the main motor pathways, such as the corticospinal tract, in the perinatal period contributes substantially to clinical outcome. Advanced neuroimaging techniques have led to greater understanding of the nature of both white and gray matter injury in preterm infants. Further research is warranted to examine the translational potential of preclinical therapeutic strategies for controlling such injury and preserving the integrity of motor pathways in preterm infants. PMID: 20479779 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Promoter DNA methylation patterns of differentiated cells are largely programmed at the progenitor stage. Mol Biol Cell. 2010 Jun 15;21(12):2066-77 Authors: Sørensen AL, Jacobsen BM, Reiner AH, Andersen IS, Collas P Mesenchymal stem cells (MSCs) isolated from various tissues share common phenotypic and functional properties. However, intrinsic molecular evidence supporting these observations has been lacking. Here, we unravel overlapping genome-wide promoter DNA methylation patterns between MSCs from adipose tissue, bone marrow, and skeletal muscle, whereas hematopoietic progenitors are more epigenetically distant from MSCs as a whole. Commonly hypermethylated genes are enriched in signaling, metabolic, and developmental functions, whereas genes hypermethylated only in MSCs are associated with early development functions. We find that most lineage-specification promoters are DNA hypomethylated and harbor a combination of trimethylated H3K4 and H3K27, whereas early developmental genes are DNA hypermethylated with or without H3K27 methylation. Promoter DNA methylation patterns of differentiated cells are largely established at the progenitor stage; yet, differentiation segregates a minor fraction of the commonly hypermethylated promoters, generating greater epigenetic divergence between differentiated cell types than between their undifferentiated counterparts. We also show an effect of promoter CpG content on methylation dynamics upon differentiation and distinct methylation profiles on transcriptionally active and inactive promoters. We infer that methylation state of lineage-specific promoters in MSCs is not a primary determinant of differentiation capacity. Our results support the view of a common origin of mesenchymal progenitors. PMID: 20410135 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Spatial and temporal expression pattern of germ layer markers during human embryonic stem cell differentiation in embryoid bodies. Histochem Cell Biol. 2010 May;133(5):595-606 Authors: Pekkanen-Mattila M, Pelto-Huikko M, Kujala V, Suuronen R, Skottman H, Aalto-Setälä K, Kerkelä E Human embryonic stem cell (hESC) differentiation in embryoid bodies (EBs) provides a valuable tool to study the interplay of different germ layers and their influence on cell differentiation. The gene expression of the developing EBs has been shown in many studies, but the protein expression and the spatial composition of different germ layers in human EBs have not been systematically studied. The aim of the present work was to study the temporal and spatial organisation of germ layers based on the expression of mesoderm (Brachyury T), endoderm (AFP) and ectoderm (SOX1) markers during the early stages of differentiation in eight hESC lines. Tissue multi-array technology was applied to study the protein expression of a large number of EBs. According to our results, EB formation and the organisation of germ layers occurred in a similar manner in all the lines. During 12 days of differentiation, all the germ layer markers were present, but no obvious distinct trajectories were formed. However, older EBs were highly organised in structure. Pluripotency marker OCT3/4 expression persisted unexpectedly long in the differentiating EBs. Cavity formation was observed in the immunocytological sections, and caspase-3 expression was high, suggesting a role of apoptosis in hESC differentiation and/or EB formation. The expression of Brachyury T was notably low in all the lines, also those with the best cardiac differentiation capacity, while the expression of SOX1 was higher in some lines, suggesting that the neural differentiation propensity may be detectable already in the early stages of EB differentiation. PMID: 20369364 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Tissue-engineered pro-angiogenic fibroblast scaffold improves myocardial perfusion and function and limits ventricular remodeling after infarction. J Thorac Cardiovasc Surg. 2010 Sep;140(3):667-76 Authors: Fitzpatrick JR, Frederick JR, McCormick RC, Harris DA, Kim AY, Muenzer JR, Gambogi AJ, Liu JP, Paulson EC, Woo YJ OBJECTIVE: Microvascular malperfusion after myocardial infarction leads to infarct expansion, adverse remodeling, and functional impairment. Native reparative mechanisms exist but are inadequate to vascularize ischemic myocardium. We hypothesized that a 3-dimensional human fibroblast culture (3DFC) functions as a sustained source of angiogenic cytokines, thereby augmenting native angiogenesis and limiting adverse effects of myocardial ischemia. METHODS: Lewis rats underwent ligation of the left anterior descending coronary artery to induce heart failure; experimental animals received a 3DFC scaffold to the ischemic region. Border-zone tissue was analyzed for the presence of human fibroblast surface protein, vascular endothelial growth factor, and hepatocyte growth factor. Cardiac function was assessed with echocardiography and pressure-volume conductance. Hearts underwent immunohistochemical analysis of angiogenesis by co-localization of platelet endothelial cell adhesion molecule and alpha smooth muscle actin and by digital analysis of ventricular geometry. Microvascular angiography was performed with fluorescein-labeled lectin to assess perfusion. RESULTS: Immunoblotting confirmed the presence of human fibroblast surface protein in rats receiving 3DFC, indicating survival of transplanted cells. Increased expression of vascular endothelial growth factor and hepatocyte growth factor in experimental rats confirmed elution by the 3DFC. Microvasculature expressing platelet endothelial cell adhesion molecule/alpha smooth muscle actin was increased in infarct and border-zone regions of rats receiving 3DFC. Microvascular perfusion was also improved in infarct and border-zone regions in these rats. Rats receiving 3DFC had increased wall thickness, smaller infarct area, and smaller infarct fraction. Echocardiography and pressure-volume measurements showed that cardiac function was preserved in these rats. CONCLUSIONS: Application of a bioengineered 3DFC augments native angiogenesis through delivery of angiogenic cytokines to ischemic myocardium. This yields improved microvascular perfusion, limits infarct progression and adverse remodeling, and improves ventricular function. PMID: 20363480 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Prominin-2 is a novel marker of distal tubules and collecting ducts of the human and murine kidney. Histochem Cell Biol. 2010 May;133(5):527-39 Authors: Jászai J, Farkas LM, Fargeas CA, Janich P, Haase M, Huttner WB, Corbeil D Prominin-1 (CD133) and its paralogue, prominin-2, are pentaspan membrane glycoproteins that are strongly expressed in the kidney where they have been originally cloned from. Previously, we have described the localization of prominin-1 in proximal tubules of the nephron. The spatial distribution of prominin-2, however, has not yet been documented in the kidney. We therefore examined the expression of this molecule along distinct tubular segments of the human and murine nephron using in situ hybridization and immunohistochemistry. Our findings indicated that human prominin-2 transcripts and protein were confined to distal tubules of the nephron including the thick ascending limb of Henle's loop and the distal convoluted tubule, the connecting duct and to the collecting duct system. Therein, this glycoprotein was enriched at the basolateral plasma membrane of the tubular epithelial cells with exception of the thick ascending limb where it was also found in the apical domain. This is in contrast with the exclusive apical localization of prominin-1 in epithelial cells of proximal nephron tubules. The distribution of murine prominin-2 transcripts was reminiscent of its human orthologue. In addition, a marked enrichment in the epithelium covering the papilla and in the urothelium of the renal pelvis was noted in mice. Finally, our biochemical analysis revealed that prominin-2 was released into the clinically healthy human urine as a constituent of small membrane vesicles. Collectively our data show the distribution and subcellular localization of prominin-2 within the kidney in situ and its release into the urine. Urinary detection of this protein might offer novel diagnostic approaches for studying renal diseases affecting distal segments of the nephron. PMID: 20333396 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Testicular germline stem cells. Nat Rev Urol. 2010 Feb;7(2):94-100 Authors: Kee K, Pera RA, Turek PJ Stem cells have the ability to both differentiate into other mature cell types and maintain an undifferentiated state by self-renewal. These unique properties form the basis for stem cell use in organ replacement and tissue regeneration in clinical medicine. Currently, embryonic stem cells are the best-studied stem cell type. However alternative stem cells such as induced pluripotent stem cells and other adult stem cells are also being actively investigated for their potential for cell-based therapy. Among adult stem cells, emerging research has focused on evaluating the pluripotency potential of testis stem cells. To date, stem cells with embryonic-like potential have been created from adult testis germ cells. These cells could provide patient-specific, non-embryo-derived stem cells for men in the future. PMID: 20084076 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of Buguzhi (Psoralea corylifolia fruit) extract on bone formation. Phytother Res. 2010 Jun;24 Suppl 2:S155-60 Authors: Wong RW, Rabie AB The objective of the study is to compare the amount of new bone produced by Buguzhi (Psoralea corylifolia fruit) extract in collagen matrix to that produced and collagen matrix in vivo. Eighteen bone defects, 5 mm by 10 mm, were created in the parietal bone of 9 New Zealand white rabbits. Six defects were grafted with Buguzhi extract mixed with collagen matrix. Six defects were grafted with collagen matrix alone (positive control) and 6 were left empty (negative control). Animals were sacrificed on day 14 and the defects were dissected and prepared for histological assessment. Quantitative analysis of new bone formation and bone cells was made on 100 sections (50 sections for each group) using image analysis. A total of 275% more new bone was present in defects grafted with Buguzhi extract in collagen matrix than those grafted with collagen matrix. No bone was formed in the negative control group. The amount of bone cells was also significantly greater in the Buguzhi group than in the positive control group. To conclude, Buguzhi extract in collagen matrix has the effect of increasing new bone formation locally in vivo. Buguzhi extract in collagen matrix can be used as a bone graft material. PMID: 19953524 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Biological basis for the use of autologous bone marrow stromal cells in the treatment of congenital pseudarthrosis of the tibia. Bone. 2010 Mar;46(3):780-8 Authors: Granchi D, Devescovi V, Baglìo SR, Leonardi E, Donzelli O, Magnani M, Stilli S, Giunti A, Baldini N The study was designed to establish the biological basis for the use of autologous bone-marrow stromal cells (MSC) in order to improve the curing opportunities of congenital pseudarthrosis of the tibia (CPT). The investigation was planned by taking into account that the pathophysiology of bone healing mainly depends on the osteogenic potential of the resident cells, although several factors play a crucial role in restoring the normal bone structure. Bone marrow samples were collected from the lesion site (P) and the iliac crest (IC) of 7 patients affected by CPT and type 1 neurofibromatosis (NF1+) and 6 patients affected by CPT without NF1 (NF1-). Four patients without CPT served as control group. Biochemical, functional and molecular assays showed that the ability to generate bone-forming cells was higher in IC-MSC than in P-MSC, but lower in CPT patients than in control group. We evaluated whether host factors, such as autologous serum and the microenvironment surrounding the pseudarthrosis lesion, could impair the osteogenic differentiation of IC-MSC. Autologous serum was less effective than FBS in promoting the IC-MSC differentiation, but the damage was more evident in NF1- than in NF1+ patients. Additionally, the supernatant of osteoblast cultures obtained from bone fragments close to the lesion site favoured the differentiation of IC-MSC in NF1- patients. In summary, our results suggest that MSC transplantation could be a promising strategy for the therapy of CPT. Further studies are warranted to confirm the clinical effectiveness in comparison to standard surgical treatment. PMID: 19900596 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Acellular dermal equivalent derived from fibroblast culture alone. Clin Exp Dermatol. 2010 Mar;35(2):197-9 Authors: Lee DY PMID: 19456769 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |  | |  | |  |
No comments:
Post a Comment