|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | [Research progress of bone marrow mesenchymal stem cells in acute lung injury]. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2011 Feb;25(2):198-201 Authors: Zhu F, Guo G To review the basic research, the clinical progress, and the mechanism of bone marrow mesenchymal stem cells (BMSCs) in acute lung injury (ALI). PMID: 21427850 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Mesenchymal stem cell therapy of Crohn's disease: are the far-away hills getting closer? Gut. 2011 Mar 22; Authors: Panés J, Benitez-Ribas D, Salas A PMID: 21427198 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Modeling of gene therapy for regenerative cells using intelligent agents. Adv Exp Med Biol. 2011;696:317-25 Authors: Adly AS, Aboutabl AE, Ibrahim MS Gene therapy is an exciting field that has attracted much interest since the first submission of clinical trials. Preliminary results were very encouraging and prompted many investigators and researchers. However, the ability of stem cells to differentiate into specific cell types holds immense potential for therapeutic use in gene therapy. Realization of this potential depends on efficient and optimized protocols for genetic manipulation of stem cells. It is widely recognized that gain/loss of function approaches using gene therapy are essential for understanding specific genes functions, and such approaches would be particularly valuable in studies involving stem cells. A significant complexity is that the development stage of vectors and their variety are still not sufficient to be efficiently applied in stem cell therapy. The development of scalable computer systems constitutes one step toward understanding dynamics of its potential. Therefore, the primary goal of this work is to develop a computer model that will support investigations of virus' behavior and organization on regenerative tissues including genetically modified stem cells. Different simulation scenarios were implemented, and their results were encouraging compared to ex vivo experiments, where the error rate lies in the range of acceptable values in this domain of application. PMID: 21431572 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Cell-fusion-mediated reprogramming: pluripotency or transdifferentiation? Implications for regenerative medicine. Adv Exp Med Biol. 2011;713:137-59 Authors: Sanges D, Lluis F, Cosma MP Cell-cell fusion is a natural process that occurs not only during development, but as has emerged over the last few years, also with an important role in tissue regeneration. Interestingly, in-vitro studies have revealed that after fusion of two different cell types, the developmental potential of these cells can change. This suggests that the mechanisms by which cells differentiate during development to acquire their identities is not irreversible, as was considered until a few years ago. To date, it is well established that the fate of a cell can be changed by a process known as reprogramming. This mainly occurs in two different ways: the differentiated state of a cell can be reversed back into a pluripotent state (pluripotent reprogramming), or it can be switched directly to a different differentiated state (lineage reprogramming). In both cases, these possibilities of obtaining sources of autologous somatic cells to maintain, replace or rescue different tissues has provided new and fundamental insights in the stem-cell-therapy field. Most interestingly, the concept that cell reprogramming can also occur in vivo by spontaneous cell fusion events is also emerging, which suggests that this mechanism can be implicated not only in cellular plasticity, but also in tissue regeneration. In this chapter, we will summarize the present knowledge of the molecular mechanisms that mediate the restoration of pluripotency in vitro through cell fusion, as well as the studies carried out over the last 3 decades on lineage reprogramming, both in vitro and in vivo. How the outcome of these studies relate to regenerative medicine applications will also be discussed. PMID: 21432018 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Salicylic acid-derived poly(anhydride-ester) electrospun fibers designed for regenerating the peripheral nervous system. J Biomed Mater Res A. 2011 Mar 25; Authors: Griffin J, Delgado-Rivera R, Meiners S, Uhrich KE Continuous biomaterial advances and the regenerating potential of the adult human peripheral nervous system offer great promise for restoring full function to innervated tissue following traumatic injury via synthetic nerve guidance conduits (NGCs). To most effectively facilitate nerve regeneration, a tissue engineering scaffold within a conduit must be similar to the linear microenvironment of the healthy nerve. To mimic the native nerve structure, aligned poly(lactic-co-glycolic acid)/bioactive polyanhydride fibrous substrates were fabricated through optimized electrospinning parameters with diameters of 600 ± 200 nm. Scanning electron microscopy images show fibers with a high degree of alignment. Schwann cells and dissociated rat dorsal root ganglia demonstrated elongated and healthy proliferation in a direction parallel to orientated electrospun fibers with significantly longer Schwann cell process length and neurite outgrowth when compared to randomly orientated fibers. Results suggest that an aligned polyanhydride fiber mat holds tremendous promise as a supplement scaffold for the interior of a degradable polymer NGC. Bioactive salicylic acid-based polyanhydride fibers are not limited to nerve regeneration and offer exciting promise for a wide variety of biomedical applications. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID: 21442724 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of nitridation on the aqueous dissolution of Na(2)O-K(2)O-CaO-P(2)O(5) metaphosphate glasses. Acta Biomater. 2011 Mar 23; Authors: Riguidel Q, Muñoz F The use of oxynitride glasses is presented as an alternative for the preparation of bioresorbable phosphate glasses with a controlled dissolution rate. This work describes the design of oxynitride phosphate glasses within the systems of composition (50-x)Na(2)O.xCaO.50P(2)O(5) and (25-(x/2))Na(2)O.(25-(x/2))K(2)O.xCaO.50P(2)O(5) (x=5,10,15,20 mol%) throughout the processing parameters of the ammonolysis reaction and the glass composition. Mixed-alkali sodium-potassium phosphate glasses with low CaO contents are those presenting the most adequate characteristics for their nitridation. The dissolution rate has been determined by immersion of glass samples in water, at constant temperature of 37°C, and it has been discussed as a function of both modifiers composition and nitrogen content incorporated in the glasses through ammonolysis. All oxynitride glass compositions dissolve congruently and their dissolution rate decreases by more than three orders of magnitude for the highest nitrogen contents. However, it has been demonstrated that nitrogen contents as low as 2-3 wt.% (i.e. 0.2 N/P ratio) are sufficient to decrease the dissolution rate by one order of magnitude with respect to the pure oxide glasses. Novel oxynitride phosphate glasses with a controlled and congruent dissolution are proposed for future applications in biodegradable composite materials, tissue engineering or host matrices for the controlled release of drugs. PMID: 21440095 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | GMP-Compliant Culture of Human Hair Follicle Cells for Encapsulation and Transplantation. Cell Transplant. 2011 Mar 25; Authors: Marazzi M, Crovato F, Bucco M, Sironi MC, Tosca MC, Antonioli B, Chlapanidas T, Lucconi G, Scalise A, Torre MF Human hair follicle cells, both bulge and dermal papilla cells, were isolated and cultured in a GMP cell factory, in order to obtain an in vitro hair follicle source for encapsulation end transplantation in alopecia regenerative cell therapy. An in vitro model, constituted by organotypic cultures of human skin sample, was set up to simulate the dermal-epidermal interaction between bulge cells and dermal papilla cells, evaluating the possible new follicles formation and the regenerative potentiality of these hair follicle cells. Both the bulge and dermal papilla cells show an excellent cellular proliferation as well as an abundant extracellular matrix production. The immunofluorescence investigation revealed the positivity of both cell lines to CK15 and CD200, whereas both cell lines were negative to CD71 and Oct-4. The pool of cultured bulge and dermal papilla cells was injected into the deep dermis; at day 28 of culture, some organized areas with a higher cell density can be observed: the cells self organize into papilla-like lengthened aggregates. In samples in which the follicular cells have been seeded on the dermis surface, an epidermis-like homogeneous monolayer on the dermis surface can be seen, therefore showing a potentiality of these cells for epidermis regeneration. These data show the efficacy of a cellular isolation and amplification approach to obtain an in vitro human hair follicle regenerative source on industrial scale in a GMP cell factory. The results also proved an intrinsic potentiality of follicular cells to in vitro recreate the epidermis for tissue engineering purposes. Thus it is feasible to produce bioengineered hair follicles in a GMP cell factory, forencapsulation and transplantation in alopecic patients. PMID: 21439132 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The tissue response to photopolymerized PEG-p(HPMAm-lactate)-based hydrogels. J Biomed Mater Res A. 2011 Mar 25; Authors: Censi R, van Putten S, Vermonden T, di Martino P, van Nostrum CF, Harmsen MC, Bank RA, Hennink WE Hydrogels are three-dimensional networks of crosslinked hydrophilic polymers widely used for protein delivery and tissue engineering. To be eligible for in vivo applications, the hydrogels should not evoke an adverse tissue response. In this study the angiogenic and inflammatory responses in vivo after implantation of photopolymerized thermosensitive poly(hydroxypropyl methacrylamide lactate)-poly(ethyl copolymer hydrogels are investigated. Hydrogels consisting of polymers with different crosslink densities were subcutaneously implanted in Balb/c mice and histological evaluation of the tissue response was performed. The implants showed an acute and localized inflammatory reaction upon implantation, mainly characterized by a strong infiltration of granulocytes. The acute inflammatory reaction was followed by a milder chronic inflammation which was characterized by infiltration of macrophages and persistent but decreasing levels of granulocytes. The number of macrophages and blood vessels was associated with the biodegradation and resorption of the biomaterial and increased in time as the degradation of the materials progressed. The observed degradation rates in vivo correlated well with previously observed in vitro degradation rates, which suggests that hydrolysis is the main mechanism governing the degradation. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID: 21442723 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Hypoxia Promotes Proliferation of Human Myogenic Satellite Cells: A Potential Benefactor in Tissue Engineering of Skeletal Muscle. Tissue Eng Part A. 2011 Mar 25; Authors: Koning M, Werker PM, van Luyn MJ, Harmsen MC Facial paralysis is a physically, psychologically, and socially disabling condition. Innovative treatment strategies based on regenerative medicine, in particular tissue engineering of skeletal muscle, are promising for treatment of patients with facial paralysis. The natural source for tissue-engineered muscle would be muscle stem cells, that is, human satellite cells (SC). In vivo, SC respond to hypoxic, ischemic muscle damage by activation, proliferation, differentiation to myotubes, and maturation to muscle fibers, while maintaining their reserve pool of SC. Therefore, our hypothesis is that hypoxia improves proliferation and differentiation of SC. During tissue engineering, a three-dimensional construct, or implanting SC in vivo, SC will encounter hypoxic environments. Thus, we set out to test our hypothesis on SC in vitro. During the first five passages, hypoxically cultured SC proliferated faster than their counterparts under normoxia. Moreover, also at higher passages, a switch from normoxia to hypoxia enhanced proliferation of SC. Hypoxia did not affect the expression of SC markers desmin and NCAM. However, the average surface expression per cell of NCAM was downregulated by hypoxia, and it also downregulated the gene expression of NCAM. The gene expression of the myogenic transcription factors PAX7, MYF5, and MYOD was upregulated by hypoxia. Moreover, gene expression of structural proteins α-sarcomeric actin, and myosins MYL1 and MYL3 was upregulated by hypoxia during differentiation. This indicates that hypoxia promotes a promyogenic shift in SC. Finally, Pax7 expression was not influenced by hypoxia and maintained in a subset of mononucleated cells, whereas these cells were devoid of structural muscle proteins. This suggests that during myogenesis in vitro, at least part of the SC adopt a quiescent, that is, reserve cells, phenotype. In conclusion, tissue engineering under hypoxic conditions would seem favorable in terms of myogenic proliferation, while maintaining the quiescent SC pool. PMID: 21438665 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Biomimetic calcium phosphate mineralization with multifunctional elastin-like recombinamers. Biomacromolecules. 2011 Mar 25; Authors: Prieto S, Shkilnyy A, Rumplasch C, Ribeiro A, Arias FJ, Rodriguez-Cabello JC, Taubert A Biomimetic hybrid materials based on a polymeric and an inorganic component such as calcium phosphate are potentially useful for bone repair. The current study reports on a new approach towards biomimetic hybrid materials using a set of recombinamers (recombinant protein materials obtained from a synthetic gene) as crystallization additive for calcium phosphate. The recombinamers contain elements from elastin, an elastic structural protein, and statherin, a salivary protein. Via genetic engineering, the basic elastin sequence was modified with the SNA15 domain of statherin, whose interaction with calcium phosphate is well established. These new materials retain the biocompatibility, "smart" nature, and desired mechanical behavior of the elastin-like recombinamer (ELR) family. Mineralization in simulated body fluid (SBF) in the presence of these recombinamers reveals surprising differences. Two of the polymers inhibit calcium phosphate deposition (although they contain the statherin segment). In contrast, the third polymer, which has a triblock structure, efficiently controls the calcium phosphate formation yielding spherical hydroxyapatite (HAP) nanoparticles with diameters from 1 to 3 nm after one week in SBF at 37 ºC. However, at lower temperatures, no precipitation is observed with any of the polymers. The data thus suggest that design of ELRs containing statherin segments and an appropriate polymer structure are the key in order to obtain attractive materials for the development of intelligent systems for hard tissue engineering and subsequent in vivo applications. PMID: 21438535 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Flow perfusion culture of human mesenchymal stem cells on coralline hydroxyapatite scaffolds with various pore sizes. J Biomed Mater Res A. 2011 Mar 25; Authors: Bjerre L, Bünger C, Baatrup A, Kassem M, Mygind T Bone grafts are widely used in orthopaedic reconstructive surgery, but harvesting of autologous grafts is limited due to donor site complications. Bone tissue engineering is a possible alternative source for substitutes, and to date, mainly small scaffold sizes have been evaluated. The aim of this study was to obtain a clinically relevant substitute size using a direct perfusion culture system. Human bone marrowderived mesenchymal stem cells were seeded on coralline hydroxyapatite scaffolds with 200 μm or 500 μm pores, and resulting constructs were cultured in a perfusion bioreactor or in static culture for up to 21 days and analysed for cell distribution and osteogenic differentiation using histological stainings, alkaline phosphatase activity assay, and real-time RT-PCR on bone markers. We found that the number of cells was higher during static culture at most time points and that the final number of cells was higher in 500 μm constructs as compared with 200 μm constructs. Alkaline phosphatase enzyme activity assays and real time RT-PCR on seven osteogenic markers showed that differentiation occurred primarily and earlier in statically cultured constructs with 200 μm pores compared with 500 μm ones. Adhesion and proliferation of the cells was seen on both scaffold sizes, but the vitality and morphology of cells changed unfavorably during perfusion culture. In contrast to previous studies using spinner flask that show increased cellularity and osteogenic properties of cells when cultured dynamically, the perfusion culture in our study did not enhance the osteogenic properties of cell/scaffold constructs. The statically cultured constructs showed increasing cell numbers and abundant osteogenic differentiation probably because of weak initial cell adhesion due to the surface morphology of scaffolds. Our conclusion is that the specific scaffold surface microstructure and culturing system flow dynamics has a great impact on cell distribution and proliferation and on osteogenic differentiation, and the data presented warrant careful selection of in vitro culture settings to meet the specific requirements of the scaffolds and cells, especially when natural biomaterials with varying morphology are used. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID: 21442726 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Mannitol-containing macroporous calcium phosphate cement encapsulating human umbilical cord stem cells. J Tissue Eng Regen Med. 2011 Mar 27; Authors: Tang M, Weir MD, Xu HH Stem cell-based tissue engineering offers immense promise for bone regeneration. The objective of this study was to develop a self-setting, mannitol-containing calcium phosphate cement (CPC) encapsulating human umbilical cord mesenchymal stem cells (hUCMSCs) for bone tissue engineering. hUCMSCs could be an inexhaustible and low-cost alternative to the gold-standard bone marrow MSCs, which require an invasive procedure to harvest. hUCMSCs were encapsulated in alginate beads and mixed into the CPC paste. Water-soluble mannitol porogen was incorporated into CPC to create macropores. The porosity was increased from 49% for the hUCMSC-encapsulating CPC to 64% after adding mannitol and absorbable-fibres (p < 0.05). Flexural strength of the construct was increased from 0.3 MPa to 2.0 MPa via fibres. Live cell percentage was > 80% for all constructs. The ALP and OC gene expressions were low at 1 day and greatly increased at 14 days. The constructs that contained mannitol had significantly higher ALP and OC expressions than that without mannitol. ALP activity of hUCMSCs inside CPC with mannitol and fibre was significantly higher than that without mannitol. At 14 days, mineralization by the encapsulated hUCMSCs was eight-fold higher than that at 1 day. In conclusion, a novel mannitol-containing porous CPC-hUCMSC construct was developed for bone tissue engineering. Its advantages include cell delivery inside a load-bearing CPC that has injectable and in situ setting capabilities. hUCMSCs inside CPC had good viability and successfully osteodifferentiated. The self-setting and strong hUCMSC-encapsulating CPC scaffold is promising for bone tissue engineering in a wide range of orthopaedic and craniofacial applications. Copyright © 2011 John Wiley & Sons, Ltd. PMID: 21442765 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Modulation of collagen II fiber formation in 3D porous scaffold environments. Acta Biomater. 2011 Mar 22; Authors: Tan GK, Dinnes DL, Cooper-White JJ Collagen II, a major extracellular matrix component in cartilaginous tissues, undergoes fibrillogenesis under physiological conditions. The present study explored collagen II fiber formation in solution, 2D (coverslip) and 3D (scaffold) environments under different incubation conditions. These conditions include variations in adsorption buffers, the presence of 1-ethyl-3-(3- dimenthylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDAC/NHS) crosslinker and the nature of the material surfaces. We extend our observations of collagen II fiber formation in 2D to develop an approach for the formation of a fibrillar collagen II network throughout surface-modified polylactideco- glycolide (PLGA) porous scaffolds. Morphologically, the collagen ll network is similar to that present in native articular cartilage. Biological validation of the resultant optimised functional scaffold, using rat bone marrow-derived mesenchymal stem cells (rMSCs), shows appreciable cell infiltration throughout the scaffold with enhanced cell spreading at 24 h post-seeding. This economic and versatile approach is thus believed to have significant potential in cartilage tissue engineering applications. PMID: 21439411 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | In vivo local co-delivery of recombinant human bone morphogenetic protein-7 and pamidronate via poly-D, L-lactic acid. Eur Cell Mater. 2010;20:431-41; discussion 441-2 Authors: Yu NY, Schindeler A, Peacock L, Mikulec K, Baldock PA, Ruys AJ, Little DG The effects of bone anabolic agents such as bone morphogenetic proteins (BMPs) have the potential to be augmented by co-treatment with an anti-catabolic such as a bisphosphonate. We hypothesised that the effects of bisphosphonates on BMP-induced bone anabolism would be dose dependent, and we aimed to test this in a small animal model. Agents were delivered locally using a biodegradable poly-D, L-lactic-acid (PDLLA) polymer delivery system. Recombinant human BMP-7 (25 µg) was tested with a range of doses of the bisphosphonate pamidronate (0.02 mg, 0.2 mg and 2 mg local PAM; 0.3 mg/kg and 3 mg/kg thrice-weekly systemic PAM) versus BMP-7 alone. Polymer pellets were surgically implanted in the hind limbs of female C57BL6/J mice (8-10 week) and ectopic bone nodules were harvested at 3 and 8 weeks post-operatively. At 3 weeks, local low dose PAM (0.02 mg) induced a 102% increase in rhBMP-7 induced bone volume (p<0.01) as measured by miroCT, and this was comparable to systemic PAM (0.3 mg/kg thrice-weekly). In contrast, local high dose PAM (2 mg) resulted in a 97% decrease in bone volume (p<0.01). Radiography and histology indicated that the polymer vehicle was still largely present at 8 weeks indicating inefficient biodegradation. This is the first study to validate the utility of local co-delivery of BMP/bisphosphonate via biodegradable polymer and supports the continued refinement of more advanced bioresorbable delivery systems for clinical applications. PMID: 21181649 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Fibronectin-Hyaluronic Acid Composite Hydrogels for Three-Dimensional Endothelial Cell Culture. Acta Biomater. 2011 Mar 22; Authors: Seidlits SK, Drinnan CT, Petersen RR, Shear JB, Suggs LJ, Schmidt CE Biomaterials that actively promote both wound healing and angiogenesis are of critical importance for many biomedical applications, including tissue engineering. In particular, hyaluronic acid (HA) is an important player that has multiple roles throughout the angiogenic process in the body. Previously, our lab has developed photocrosslinkable HA-based scaffolds that promote angiogenesis when implanted in vivo. This manuscript reports the incorporation of a photocrosslinkable fibronectin (FN) conjugate into three-dimensional (3D) HA hydrogel networks to enhance endothelial cell adhesion and angiogenesis. Results demonstrate significantly better retention of FN that was photocrosslinked within HA hydrogels compared to FN that was physically adsorbed within HA hydrogels. Increased viability of endothelial cells cultured in 3D HA hydrogels with photoimmobilized FN, compared to adsorbed FN, was also observed. Endothelial cells were cultured within hydrogels for up to six days, a period over which cell proliferation, migration, and an angiogenic phenotype were influenced by varying the concentration of incorporated FN. Results demonstrate the potential of these composite hydrogels as biomaterial scaffolds capable of promoting wound healing and angiogenesis. PMID: 21439409 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Nanoscale Hydroxyapatite Particles for Bone Tissue Engineering. Acta Biomater. 2011 Mar 23; Authors: Zhou H, Lee J Hydroxyapatite (HAp) exhibits excellent biocompatibility with soft tissues such as skin, muscle, and gums. Such capabilities make HAp an ideal candidate for orthopedic and dental implants or components of implants. Synthetic HAp has been widely used in repair of hard tissues, and common uses include bone repair, bone augmentation, as well as coating of implants or acting as fillers in bone or teeth. However, the low mechanical strength of normal HAp ceramics restricts its use mainly to conditions of low load-bearing applications. Recent advancements in nanoscience and nanotechnology have reignited investigation of HAp formation in the nanorange to clearly define small-scale properties of HAp. It has been suggested that nano-HAp may be an ideal biomaterial due to its good biocompatibility and bone integration ability. HAp biomedical material development has benefitted significantly from nanotechnology advancement. In this feature article, a new view on nano-HAp particles highlights the importance of size, crystal morphology controls, and composites with other inorganic particles in the application of biomedical material development. PMID: 21440094 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fabrication of nano-hydroxyapatite on electrospun silk fibroin nanofiber and their effects in osteoblastic behavior. J Biomed Mater Res A. 2011 Mar 25; Authors: Wei K, Li Y, Kim KO, Nakagawa Y, Kim BS, Abe K, Chen GQ, Kim IS In this study, a novel tissue engineering scaffold material of electrospun silk fibroin/nano-hydroxyapatite (nHA) biocomposite was prepared by means of an effective calcium and phosphate (Ca-P) alternate soaking method. nHA was successfully produced on regenerated silk fibroin nanofiber as a substrate within several minutes without any pretreatments. The morphologies of both nonmineralized and mineralized nanofibers were analyzed using a field-emission scanning electron microscopy (FESEM). The crystallographic phases of the nHA were analyzed using X-ray diffraction (XRD). Fourier transform infrared (FTIR) spectrophotometer and thermogravimetry analyses (TGA) were employed to determine the type of functional groups and the amount of nHA presenting in the silk/nHA biocomposite nanofibers, respectively. The osteoblastic activities of this novel nanofibrous biocomposite scaffold were also investigated by employing osteoblastic-like MC3T3-E1 cell line. The cell functionality such as alkaline phosphatase (ALP) activity was ameliorated on mineralized nanofibers. All these results indicated that this silk/nHA biocomposite scaffold material may be a promising biomaterial for bone tissue engineering. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 2011. PMID: 21442728 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Functional evaluation of primary renal cell/biomaterial Neo-Kidney Augment prototypes for renal tissue engineering. Cell Transplant. 2011 Mar 24; Authors: Ludlow JB, Halberstadt C Development of a tissue-engineered Neo-Kidney Augment (NKA) requires evaluation of defined, therapeutically-relevant cell and cell/biomaterial composites (NKA Constructs) for regenerative potential in mammalian kidney. Previous work identified primary renal cell populations that extended survival and improved renal function in a rodent model of chronic kidney disease (CKD). This study extends that work toward the goal of developing NKA by (i) screening in vivo inflammatory and fibrotic responses to acellular biomaterials delivered to healthy rodent renal parenchyma, (ii) evaluating the functionality of renal cell/biomaterial combinations in vitro, (iii) generating NKA Constructs by combining therapeutically-relevant cell populations with biocompatible biomaterial, and (iv) evaluating in vivo neo-kidney tissue development in response to NKA Constructs delivered to healthy rodent renal parenchyma. Gelatin and hyaluronic acid (HA)-based hydrogels elicited the least inflammatory and fibrotic responses in renal parenchyma relative to polycaprolactone (PCL) and poly(lactic-co-glycolic acid) (PLGA) beads or particles and were associated with neo-vascularization and cellular infiltration by 4 weeks post-implantation. Renal cell populations seeded onto gelatin or HA-based hydrogels were viable and maintained a tubular epithelial functional phenotype during an in vitro maturation of 3 days as measured by transcriptomic, proteomic, secretomic and confocal immunofluorescence assays. In vivo delivery of cell-seeded NKA Constructs (bioactive renal cells + gelatin hydrogels) to healthy rodent renal parenchyma elicited neo-kidney tissue formation at 1 week post-implantation. To investigate a potential mechanism by which NKA Constructs could impact a disease state, the effect of conditioned media on TGF- βsignaling pathways related to tubulo-interstitial fibrosis associated with CKD progression was evaluated. Conditioned medium was observed to attenuate TGF- β-induced epithelial-mesenchymal transition (EMT) in vitro in a human proximal tubular cell line (HK2). PMID: 21439130 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Mobilization of very small embryonic-like stem cells in acute coronary syndromes and stroke. Herz. 2010 Oct;35(7):467-72 Authors: Wojakowski W, Ratajczak MZ, Tendera M The bone marrow (BM) niche contains small heterogenous populations of cells which may contribute to cardiac and endothelial repair, including committed lineages [endothelial progenitor cells (EPCs), multipotent mesenchymal stromal cells (MSCs) and more primitive very small embryonic-like cells (VSELs) expressing pluripotent stem cell (PSC) markers (Oct-4, Nanog, SSEA-1)]. VSELs are present in BM, peripheral blood and some solid organs in mice and were recently identified in peripheral blood in patients with acute coronary syndromes and stroke. VSELs can be expanded in vitro and differentiated into cells from all three germ layers. This population of cells displays the morphology of primitive PSC (small size, open type chromatin, large nucleus, narrow rim of cytoplasm) and express PSC markers. The isolation of human VSELs is based on their size and presence of several surface markers (CXCR4, CD133, CD34) and lack of markers of hematopoietic lineage (lin, CD45). In acute myocardial infarction and ischemic stroke VSELs are rapidly mobilized into peripheral blood, and express increased levels of PSC markers as well as early cardiac (GATA-4, Nkx2.5/Csx), neural (GFAP, nestin, beta-III-tubulin, Olig1, Olig2, Sox2, Musashi) and endothelial lineage markers (VE-cadherin, von Willebrand factor). The number of VSELs mobilized in acute myocardial infarction is inversely correlated with left ventricular ejection fraction and the release of cardiac necrosis markers. Mobilization of these cells is also reduced in patients with diabetes and in the elderly. BM-derived VSELs were expanded and after cardiogenic pre-differentiation injected intramyocardially in mice models of myocardial infarction leading to improved left ventricular contractility. VSELs are probably progeny of epiblast cells which migrated to the BM and developing organs during embryonic development. The cells are present in a quiescent state in the adult BM and solid organs and might serve as a reserve pool of resident stem cells. VSELs are promising candidates for further pre-clinical and clinical studies on cellular cardiovascular therapy. PMID: 20981396 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Three-dimensional growth of iPS cell-derived smooth muscle cells on nanofibrous scaffolds. Biomaterials. 2011 Mar 23; Authors: Xie C, Hu J, Ma H, Zhang J, Chang LJ, Chen YE, Ma PX Induced pluripotent stem cells (iPSCs) have been considered as the major component for personalized regenerative medicine. However, the potential of iPSCs in constructing tissue-engineered (TE) blood vessels has not been exploited. In the present study, we generated mouse iPSCs with the combination of over-expression of 4 iPS factors and knock-down of p53 gene. The established iPSCs were then directed to differentiate into smooth muscle cells (SMCs) with the treatment of 10(-5) m all-trans retinoid acid (RA). The vehicle dimethyl sulfoxide (DMSO) treatment served as a spontaneous differentiation control. The differentiated cells were then cultured on three-dimensional (3D) macro-porous nanofibrous (NF) poly(l-lactide) (PLLA) scaffolds in vitro. Our data showed that the expression of SMC specific marker genes, including myocardin, smoothelin, SM22α and SMMHC, were higher for the group induced by RA than for the group treated by DMSO, while pluripotent marker gene expression was repressed by the RA-treatment. Upon subcutaneous implantation, the implanted cells maintained the SMC phenotype. In conclusion, the data suggest that iPSCs-derived SMCs can be an important cell source for personalized vascular tissue engineering applications. PMID: 21439638 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Identification of small molecular compounds and fabrication of its aqueous solution by laser-ablation, expanding primordial cartilage. Osteoarthritis Cartilage. 2011 Feb;19(2):233-41 Authors: Ikegami D, Iwai T, Ryo S, Gu N, Sugiyama T, Oh I, Yoshikawa H, Tsumaki N The discovery of small molecular compounds that expand cartilage is needed. We searched for small molecular compounds that expand cartilage or enhance the actions of bone morphogenetic proteins (BMPs) on cartilage. PMID: 21094690 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Mesenchymal stem cells: a perspective from in vitro cultures to in vivo migration and niches. Eur Cell Mater. 2010;20:121-33 Authors: Augello A, Kurth TB, De Bari C Mesenchymal Stromal Progenitor/Stem Cells (MSCs) are a rare population of non-hematopoietic stromal cells, present in the bone marrow and most connective tissues of the body. They are capable of differentiation into mesenchymal tissues such as bone, cartilage, adipose tissue and muscle. In the absence of specific markers, MSCs have been defined following isolation and culture expansion, by their expression of various molecules including CD90, CD105 and CD73 and absence of markers like CD34, CD45, and CD14. MSCs have extensive proliferative ability in culture in an uncommitted state while retaining their multilineage differentiation potential, which make them attractive candidates for biological cell-based tissue repair approaches. However, their identity in their tissues of origin is not clear and the niches in which they reside are not defined. This review addresses the current state of MSC research including the differentiation potency of culture expanded MSCs, expression of chemokines and their receptors in MSCs--both relevant issues for the advocated use of MSCs for tissue repair and their systemic delivery to the affected tissues. It also reviews current knowledge of MSC niches in their native tissues, addressing the relationship with pericytes. Finally, it provides a scientific basis for the requirement of a thorough characterisation of the endogenous MSC niches within their native tissues in vivo. The knowledge of MSC niches will instruct development of innovative therapeutic measures such as producing pharmacological substances that target endogenous MSCs and their niches in order to activate and guide intrinsic repair and to improve disease outcomes. PMID: 21249629 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Elastin-like recombinamers as substrates for retinal pigment epithelial cell growth. J Biomed Mater Res A. 2011 Mar 25; Authors: Srivastava GK, Martín L, Singh AK, Fernandez-Bueno I, Gayoso MJ, Garcia-Gutierrez MT, Girotti A, Alonso M, Rodríguez-Cabello JC, Pastor JC The aim of this study is to investigate the use of elastin-like recombinamers (ELRs) as a substrate that can maintain the growth, phenotype, and functional characteristics of retinal pigment epithelial (RPE) cells efficiently and as a suitable carrier for the transplantation of autologous RPE cells for treatment of age-related macular degeneration (AMD). ELR films containing a bioactive sequence, RGD (ELR-RGD), and one with no specific sequence (ELR-IK) as control, were obtained by solvent-casting onto glass and subsequent cross-linking. ARPE19 cells were seeded on sterilized ELR films as well as on the control surfaces. Cells were analysed after 4, 24, 72, and 120 h to study cell adhesion, proliferation, cell viability, morphology, and specificity by staining with Trypan blue, DAPI, Rhodamin-Phalloidin and RPE65, ZO-1 antibodies and observing under fluorescence as well as electron microscope. ARPE19 cells seeded on both ELR films and controls were 100% viable and maintained their morphology and set of characteristics at the different time points studied. Cell proliferation on ELR-RGD was significantly higher than that found on ELR-IK at all time points, although it was less than the growth rate on polystyrene. ARPE19 cells grow well on ELR-RGD maintaining their phenotype. These results should be extended to further studies with fresh human RPE cells and in vivo studies to determine whether this ELR-RGD matrix could be used as a Bruch's membrane prosthesis and carrier for transplantation of RPE cells in patients suffering with AMD. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID: 21442725 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | 2010 Panel on the biomaterials grand challenges. J Biomed Mater Res A. 2011 Feb;96(2):275-87 Authors: Reichert WM, Ratner BD, Anderson J, Coury A, Hoffman AS, Laurencin CT, Tirrell D In 2009, the National Academy for Engineering issued the Grand Challenges for Engineering in the 21st Century comprised of 14 technical challenges that must be addressed to build a healthy, profitable, sustainable, and secure global community (http://www.engineeringchallenges.org). Although crucial, none of the NEA Grand Challenges adequately addressed the challenges that face the biomaterials community. In response to the NAE Grand Challenges, Monty Reichert of Duke University organized a panel entitled Grand Challenges in Biomaterials at the at the 2010 Society for Biomaterials Annual Meeting in Seattle. Six members of the National Academies-Buddy Ratner, James Anderson, Allan Hoffman, Art Coury, Cato Laurencin, and David Tirrell-were asked to propose a grand challenge to the audience that, if met, would significantly impact the future of biomaterials and medical devices. Successfully meeting these challenges will speed the 60-plus year transition from commodity, off-the-shelf biomaterials to bioengineered chemistries, and biomaterial devices that will significantly advance our ability to address patient needs and also to create new market opportunities. PMID: 21171147 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Mesenchymal stem cells ameliorate the histopathological changes in a murine model of chronic asthma. Int Immunopharmacol. 2011 Mar 22; Authors: Firinci F, Karaman M, Baran Y, Bagriyanik A, Ayyildiz ZA, Kiray M, Kozanoglu I, Yilmaz O, Uzuner N, Karaman O Asthma therapies are effective in reducing inflammation but airway remodeling is poorly responsive to these agents. New therapeutic options that have fewer side effects and reverse chronic changes in the lungs are essential. MSCs are non-immunogenic and immunosuppressive with the ability to inhibit maturation of dendritic cells and suppress the function of naive and memory T cells, B cells, and NK cells. Mesenchymal stem cells (MSCs) are promising for the development of novel therapies in regenerative medicine. This study aimed to examine the efficacy of MSCs on lung histopathology in a murine model of chronic asthma. BALB/c mice were divided into four groups: Group 1 (control group, n=6), Group 2 (ovalbumin induced asthma only, n=10), Group 3 (ovalbumin induced asthma + MSCs, n=10), and Group 4 (MSCs only, n=10). Histological findings (basement membrane, epithelium, subepithelial smooth muscle thickness, numbers of goblet and mast cells) of the airways and MSC migration were evaluated by light, electron, and confocal microscopes. In Group 3, all early histopathological changes except epithelial thickness and all of the chronic changes were significantly ameliorated when compared with Group 2. Evaluation with confocal microscopy showed that no noteworthy amount of MSCs were present in the lung tissues of Group 4 while significant amount of MSCs was detected in Group 3. Serum NO levels in Group 3, were significantly lower than Group 2. The results of this study revealed that MSCs migrated to lung tissue and ameliorated bronchial asthma in murine model. Further studies are needed to evaluate the efficacy of MSCs for the treatment of asthma. PMID: 21439399 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Three-dimensional growth of iPS cell-derived smooth muscle cells on nanofibrous scaffolds. Biomaterials. 2011 Mar 23; Authors: Xie C, Hu J, Ma H, Zhang J, Chang LJ, Chen YE, Ma PX Induced pluripotent stem cells (iPSCs) have been considered as the major component for personalized regenerative medicine. However, the potential of iPSCs in constructing tissue-engineered (TE) blood vessels has not been exploited. In the present study, we generated mouse iPSCs with the combination of over-expression of 4 iPS factors and knock-down of p53 gene. The established iPSCs were then directed to differentiate into smooth muscle cells (SMCs) with the treatment of 10(-5) m all-trans retinoid acid (RA). The vehicle dimethyl sulfoxide (DMSO) treatment served as a spontaneous differentiation control. The differentiated cells were then cultured on three-dimensional (3D) macro-porous nanofibrous (NF) poly(l-lactide) (PLLA) scaffolds in vitro. Our data showed that the expression of SMC specific marker genes, including myocardin, smoothelin, SM22α and SMMHC, were higher for the group induced by RA than for the group treated by DMSO, while pluripotent marker gene expression was repressed by the RA-treatment. Upon subcutaneous implantation, the implanted cells maintained the SMC phenotype. In conclusion, the data suggest that iPSCs-derived SMCs can be an important cell source for personalized vascular tissue engineering applications. PMID: 21439638 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The dangers in adopting a tissue-engineering-centric agenda: a president's perspective. J Biomed Mater Res A. 2011 Feb;96(2):273-4 Authors: Gilbert JL PMID: 21171146 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Hypoxia Promotes Proliferation of Human Myogenic Satellite Cells: A Potential Benefactor in Tissue Engineering of Skeletal Muscle. Tissue Eng Part A. 2011 Mar 25; Authors: Koning M, Werker PM, van Luyn MJ, Harmsen MC Facial paralysis is a physically, psychologically, and socially disabling condition. Innovative treatment strategies based on regenerative medicine, in particular tissue engineering of skeletal muscle, are promising for treatment of patients with facial paralysis. The natural source for tissue-engineered muscle would be muscle stem cells, that is, human satellite cells (SC). In vivo, SC respond to hypoxic, ischemic muscle damage by activation, proliferation, differentiation to myotubes, and maturation to muscle fibers, while maintaining their reserve pool of SC. Therefore, our hypothesis is that hypoxia improves proliferation and differentiation of SC. During tissue engineering, a three-dimensional construct, or implanting SC in vivo, SC will encounter hypoxic environments. Thus, we set out to test our hypothesis on SC in vitro. During the first five passages, hypoxically cultured SC proliferated faster than their counterparts under normoxia. Moreover, also at higher passages, a switch from normoxia to hypoxia enhanced proliferation of SC. Hypoxia did not affect the expression of SC markers desmin and NCAM. However, the average surface expression per cell of NCAM was downregulated by hypoxia, and it also downregulated the gene expression of NCAM. The gene expression of the myogenic transcription factors PAX7, MYF5, and MYOD was upregulated by hypoxia. Moreover, gene expression of structural proteins α-sarcomeric actin, and myosins MYL1 and MYL3 was upregulated by hypoxia during differentiation. This indicates that hypoxia promotes a promyogenic shift in SC. Finally, Pax7 expression was not influenced by hypoxia and maintained in a subset of mononucleated cells, whereas these cells were devoid of structural muscle proteins. This suggests that during myogenesis in vitro, at least part of the SC adopt a quiescent, that is, reserve cells, phenotype. In conclusion, tissue engineering under hypoxic conditions would seem favorable in terms of myogenic proliferation, while maintaining the quiescent SC pool. PMID: 21438665 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Notch signaling regulates murine atrioventricular conduction and the formation of accessory pathways. J Clin Invest. 2011 Feb 1;121(2):525-33 Authors: Rentschler S, Harris BS, Kuznekoff L, Jain R, Manderfield L, Lu MM, Morley GE, Patel VV, Epstein JA Ventricular preexcitation, which characterizes Wolff-Parkinson-White syndrome, is caused by the presence of accessory pathways that can rapidly conduct electrical impulses from atria to ventricles, without the intrinsic delay characteristic of the atrioventricular (AV) node. Preexcitation is associated with an increased risk of tachyarrhythmia, palpitations, syncope, and sudden death. Although the pathology and electrophysiology of preexcitation syndromes are well characterized, the developmental mechanisms are poorly understood, and few animal models that faithfully recapitulate the human disorder have been described. Here we show that activation of Notch signaling in the developing myocardium of mice can produce fully penetrant accessory pathways and ventricular preexcitation. Conversely, inhibition of Notch signaling in the developing myocardium resulted in a hypoplastic AV node, with specific loss of slow-conducting cells expressing connexin-30.2 (Cx30.2) and a resulting loss of physiologic AV conduction delay. Taken together, our results suggest that Notch regulates the functional maturation of AV canal embryonic myocardium during the development of the specialized conduction system. Our results also show that ventricular preexcitation can arise from inappropriate patterning of the AV canal-derived myocardium. PMID: 21266778 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Mesenchymal stem cells: a perspective from in vitro cultures to in vivo migration and niches. Eur Cell Mater. 2010;20:121-33 Authors: Augello A, Kurth TB, De Bari C Mesenchymal Stromal Progenitor/Stem Cells (MSCs) are a rare population of non-hematopoietic stromal cells, present in the bone marrow and most connective tissues of the body. They are capable of differentiation into mesenchymal tissues such as bone, cartilage, adipose tissue and muscle. In the absence of specific markers, MSCs have been defined following isolation and culture expansion, by their expression of various molecules including CD90, CD105 and CD73 and absence of markers like CD34, CD45, and CD14. MSCs have extensive proliferative ability in culture in an uncommitted state while retaining their multilineage differentiation potential, which make them attractive candidates for biological cell-based tissue repair approaches. However, their identity in their tissues of origin is not clear and the niches in which they reside are not defined. This review addresses the current state of MSC research including the differentiation potency of culture expanded MSCs, expression of chemokines and their receptors in MSCs--both relevant issues for the advocated use of MSCs for tissue repair and their systemic delivery to the affected tissues. It also reviews current knowledge of MSC niches in their native tissues, addressing the relationship with pericytes. Finally, it provides a scientific basis for the requirement of a thorough characterisation of the endogenous MSC niches within their native tissues in vivo. The knowledge of MSC niches will instruct development of innovative therapeutic measures such as producing pharmacological substances that target endogenous MSCs and their niches in order to activate and guide intrinsic repair and to improve disease outcomes. PMID: 21249629 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
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