|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Restoration of motor control and dopaminergic activity in rats with unilateral 6-hydroxy-dopamine lesions. Regen Med. 2011 May;6(3):319-26 Authors: Skinner SJ, Lin H, Geaney MS, Gorba T, Elliott RB, Tan PLj Aim: To restore motor function and dopaminergic activity in the nigrostriatum of rats with unilateral 6-hydroxy-dopamine lesions using implants of encapsulated porcine choroid plexus cells. Materials & methods: Neonatal porcine choroid plexus cells were prepared and maintained in culture, then encapsulated within alginate-polyornithine capsules (600-660 µm). Rats were unilaterally injected with 6-hydroxy-dopamine into the striatum. Those with lesions verified after 2 and 4 weeks were selected for experiments. Rats were implanted adjacent to the lesion with ten capsules 2-4 days later with (treated, n = 12) or without (control, n = 10) choroid plexus cells. Results: The choroid plexus cells were shown to produce a wide range of neurorestorative proteins. The treated group had a 60% improvement in motor behavior compared with the control group (p < 0.01). The treated group also had a significant improvement in nigrostriatal dopaminergic activity (31%, p < 0.02). Conclusion: Capsules containing porcine choroid plexus cells release therapeutic molecules that stimulate regeneration of the lesioned nigrostriatum in rats. PMID: 21548737 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Cell-based cardiovascular repair and regeneration in acute myocardial infarction and chronic ischemic cardiomyopathy – current status and future developments. Int J Dev Biol. 2011 Mar 8; Authors: Templin C, Lüscher TF, Landmesser U Ischemic heart disease is the main cause of death and morbidity in most industrialized countries. Stem- and progenitor cell-based treatment approaches for ischemic heart disease are therefore an important frontier in cardiovascular and regenerative medicine. Experimental studies have shown that bone-marrow-derived stem cells and endothelial progenitor cells can improve cardiac function after myocardial infarction, clinical phase I and II studies were rapidly initiated to translate this concept into the clinical setting. However, as of now the effects of stem/progenitor cell administration on cardiac function in the clinical setting have not met expectations. Thus, a better understanding of causes of the current limitations of cell-based therapies is urgently required. Importantly, the number and function of endothelial progenitor cells is reduced in patients with cardiovascular risk factors and/or coronary artery disease. These observations may provide opportunities for an optimization of cell-based treatment approaches. This review provides a summary of current evidence for the role and potential of stem and progenitor cells in the pathophysiology and treatment of ischemic heart disease, including the properties, and repair and regenerative capacities of various stem and progenitor cell populations. In addition, we describe modes of stem/progenitor cell delivery, modulation of their homing as well as potential approaches to "prime" stem/progenitor cells for cardiovascular cell-based therapies. PMID: 21553380 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Baculovirus as a gene delivery vector: Recent understandings of molecular alterations in transduced cells and latest applications. Biotechnol Adv. 2011 Apr 28; Authors: Chen CY, Lin CY, Chen GY, Hu YC Baculovirus infects insects in nature and is non-pathogenic to humans, but can transduce a broad range of mammalian and avian cells. Thanks to the biosafety, large cloning capacity, low cytotoxicity and non-replication nature in the transduced cells as well as the ease of manipulation and production, baculovirus has gained explosive popularity as a gene delivery vector for a wide variety of applications. This article extensively reviews the recent understandings of the molecular mechanisms pertinent to baculovirus entry and cellular responses, and covers the latest advances in the vector improvements and applications, with special emphasis on antiviral therapy, cancer therapy, regenerative medicine and vaccine. PMID: 21550393 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Living bacterial sacrificial porogens to engineer decellularized porous scaffolds. PLoS One. 2011;6(4):e19344 Authors: Xu F, Sridharan B, Durmus NG, Wang S, Yavuz AS, Gurkan UA, Demirci U Decellularization and cellularization of organs have emerged as disruptive methods in tissue engineering and regenerative medicine. Porous hydrogel scaffolds have widespread applications in tissue engineering, regenerative medicine and drug discovery as viable tissue mimics. However, the existing hydrogel fabrication techniques suffer from limited control over pore interconnectivity, density and size, which leads to inefficient nutrient and oxygen transport to cells embedded in the scaffolds. Here, we demonstrated an innovative approach to develop a new platform for tissue engineered constructs using live bacteria as sacrificial porogens. E.coli were patterned and cultured in an interconnected three-dimensional (3D) hydrogel network. The growing bacteria created interconnected micropores and microchannels. Then, the scafold was decellularized, and bacteria were eliminated from the scaffold through lysing and washing steps. This 3D porous network method combined with bioprinting has the potential to be broadly applicable and compatible with tissue specific applications allowing seeding of stem cells and other cell types. PMID: 21552485 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Deadly teamwork: neural cancer stem cells and the tumor microenvironment. Cell Stem Cell. 2011 May 6;8(5):482-5 Authors: Lathia JD, Heddleston JM, Venere M, Rich JN Neural cancers display cellular hierarchies with self-renewing tumorigenic cancer stem cells (CSCs) at the apex. Instructive cues to maintain CSCs are generated by both intrinsic networks and the niche microenvironment. The CSC-microenvironment relationship is complex, as CSCs can modify their environment and extrinsic forces induce plasticity in the cellular hierarchy. PMID: 21549324 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Current strategies for osteochondral regeneration: from stem cells to pre-clinical approaches. Curr Opin Biotechnol. 2011 May 6; Authors: Rodrigues MT, Gomes ME, Reis RL Damaged cartilage tissue has no functional replacement alternatives and current therapies for bone injury treatment are far from being the ideal solutions emphasizing an urgent need for alternative therapeutic approaches for osteochondral (OC) regeneration. The tissue engineering field provides new possibilities for therapeutics and regeneration in rheumatology and orthopaedics, holding the potential for improving the quality of life of millions of patients by exploring new strategies towards the development of biological substitutes to maintain, repair and improve OC tissue function. Numerous studies have focused on the development of distinct tissue engineering strategies that could result in promising solutions for this delicate interface. In order to outperform currently used methods, novel tissue engineering approaches propose, for example, the design of multi-layered scaffolds, the use of stem cells, bioreactors or the combination of clinical techniques. PMID: 21550794 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | An Automated High Throughput Screening-Compatible Assay to Identify Regulators of Stem Cell Neural Differentiation. Mol Biotechnol. 2011 May 8; Authors: Casalino L, Magnani D, De Falco S, Filosa S, Minchiotti G, Patriarca EJ, De Cesare D The use of Embryonic Stem Cells (ESCs) holds considerable promise both for drug discovery programs and the treatment of degenerative disorders in regenerative medicine approaches. Nevertheless, the successful use of ESCs is still limited by the lack of efficient control of ESC self-renewal and differentiation capabilities. In this context, the possibility to modulate ESC biological properties and to obtain homogenous populations of correctly specified cells will help developing physiologically relevant screens, designed for the identification of stem cell modulators. Here, we developed a high throughput screening-suitable ESC neural differentiation assay by exploiting the Cell (maker) robotic platform and demonstrated that neural progenies can be generated from ESCs in complete automation, with high standards of accuracy and reliability. Moreover, we performed a pilot screening providing proof of concept that this assay allows the identification of regulators of ESC neural differentiation in full automation. PMID: 21553282 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Anti-inflammatory protein TSG-6 secreted by activated MSCs attenuates zymosan-induced mouse peritonitis by decreasing TLR2/NF-{kappa}B signaling in resident macrophages. Blood. 2011 May 6; Authors: Choi H, Lee RH, Bazhanov N, Oh JY, Prockop DJ Human mesenchymal stem/progenitor cells (hMSCs) repair tissues and modulate immune systems but the mechanisms are not fully understood. Here we demonstrated that hMSCs are activated by inflammatory signals to secrete the anti-inflammatory protein, TSG-6 and thereby create a negative feedback loop that reduces inflammation in zymosan-induced peritonitis. The results demonstrate for the first time that TSG-6 interacts through the CD44 receptor on resident macrophages to decrease zymosan/TLR2 mediated nuclear translocation of NF-κB. The negative feedback loop created by MSC through TSG-6 attenuates the inflammatory cascade that is initiated by resident macrophages and then amplified by mesothelial cells and probably other cells of the peritoneum. Because inflammation underlies many pathological processes, including immune responses, the results may explain the beneficial effects of MSCs and TSG-6 in several disease models. PMID: 21551236 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Parthenogenetically activated human oocytes and parthenogenetic embryonic stem cells: US20100233143. Expert Opin Ther Pat. 2011 May 9; Authors: Taupin P Background: The application (US20100233143) is in the field of embryonic stems cells (ESCs) and the generation of ESCs from parthenogenetically activated human oocytes. Objective: It aims at determining optimal conditions for parthenogenetically activating human oocytes. Methods: Oocytes isolated from female donors were activated in vitro in the presence of an ionophore at high oxygen (O(2)) tension and by a serine-threonine kinase inhibitor under low O(2) tension. The blastocysts were transferred to a feeder layer, and the inner cell masses (ICMs) were mechanically isolated. Results: Human ESCs were derived from the ICMs of the parthenogenetically activated oocytes. Conclusion: Parthenogenetic ESCs (pESCs) provide a model for cellular therapy and regenerative medicine. The paradigm may be used for generating isogenic cells lines relative to the donors. The application claims the method for parthenogenetically activating human oocytes, including cryopreserved oocytes or parthenotes, and for generating pESC lines for therapy and drug discovery. The application further claims the establishment of a cell bank of human pESCs. PMID: 21548850 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Acknowledgements. Regen Med. 2011 May;6(3):415 Authors: PMID: 21548742 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Self-renewal and scalability of human embryonic stem cells for human therapy. Regen Med. 2011 May;6(3):327-34 Authors: Fu X, Xu Y Human embryonic stem cells (hESCs) can undergo unlimited self-renewal and retain the pluripotency to differentiate into all cell types in the body. Therefore, as a renewable source of various cell types, hESCs hold great promise for human cell replacement therapy. While significant progress has been made in establishing the culture conditions for the long-term self-renewal of hESCs, several challenges remain to be overcome for the clinical application of hESCs. One such challenge is to develop strategies to scale-up the production of clinic-grade hESCs in xeno-free and chemically defined medium without inducing genomic instability. To achieve this goal, it is critical to elucidate the molecular pathways required to maintain the self-renewal, survival and genomic stability of hESCs. This article describes recent progress in addressing this challenge and discusses the strategies to improve the scalability of the production of hESCs by inhibiting their apoptosis. PMID: 21548738 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Identification and functional analysis of novel genes expressed in the Anterior Visceral Endoderm. Int J Dev Biol. 2011 May 6; Authors: Gonçalves L, Filipe M, Marques S, Salgueiro AM, Becker JD, Belo JA During early vertebrate development, the correct establishment of the body axes is critical. The anterior pole of the mouse embryo is established when Distal Visceral Endoderm (DVE) cells migrate to form the Anterior Visceral Endoderm (AVE). Symmetrical expression of Lefty1, Cer1 and Dkk1 determines the direction of DVE migration and the future anterior side. In addition to the establishment of the Anterior-Posterior axis, the AVE has also been implicated in anterior neural specification. To better understand the role of the AVE in these processes, we have performed a differential screening using Affymetrix GeneChip technology with AVE cells isolated from cer1 P-EGFP transgenic mouse embryos. We found 175 genes which were upregulated in the AVE and 36 genes in the Proximal-posterior sample. Using DAVID software, we characterized the AVE cell population regarding cellular component, molecular function and biological processes. Among the genes that were found to be upregulated in the AVE, several novel genes were identified. Four of these transcripts displaying high-fold change in the AVE were further characterized by in situ hybridization in early stages of development in order to validate the screening. From those four selected genes, one, denominated Adtk1, was chosen to be functionally characterized by targeted inactivation in ES cells. Adtk1 encodes for a serine/threonine kinase. Adtk1 null mutants are smaller and present short limbs due to decreased mineralization, suggesting a potential role in chondrogenesis during limb development. Taken together, these data point to the importance of reporting novel genes present in the AVE. PMID: 21553379 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Will fish foster regenerative medicine in man? Nephrol Dial Transplant. 2011 May 5; Authors: Benigni A PMID: 21551091 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of a direct thrombin inhibitor compared with dalteparin and unfractionated heparin on human osteoblasts. Open Orthop J. 2011;5:52-8 Authors: Winkler T, Perka C, Matziolis D, Matziolis G Osteoporosis is a relevant problem after long term administration of unfractionated heparin (UFH) and low molecular weight heparin. Melagatran is a representative of a new group of direct thrombin inhibitors with comparable data in the prevention of thromboembolic events after orthopaedic surgery. The aim of our in vitro study was to investigate the effect of a direct thrombin inhibitor compared with dalteparin and UFH on human osteoblasts. PMID: 21552458 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Achieving stable human stem cell engraftment and survival in the CNS: is the future of regenerative medicine immunodeficient? Regen Med. 2011 May;6(3):367-406 Authors: Anderson AJ, Haus DL, Hooshmand MJ, Perez H, Sontag CJ, Cummings BJ There is potential for a variety of stem cell populations to mediate repair in the diseased or injured CNS; in some cases, this theoretical possibility has already transitioned to clinical safety testing. However, careful consideration of preclinical animal models is essential to provide an appropriate assessment of stem cell safety and efficacy, as well as the basic biological mechanisms of stem cell action. This article examines the lessons learned from early tissue, organ and hematopoietic grafting, the early assumptions of the stem cell and CNS fields with regard to immunoprivilege, and the history of success in stem cell transplantation into the CNS. Finally, we discuss strategies in the selection of animal models to maximize the predictive validity of preclinical safety and efficacy studies. PMID: 21548741 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Advances in bone marrow-derived cell therapy: CD31-expressing cells as next generation cardiovascular cell therapy. Regen Med. 2011 May;6(3):335-49 Authors: Kim SW, Kim H, Yoon YS In the past few years, bone marrow (BM)-derived cells have been used to regenerate damaged cardiovascular tissues post-myocardial infarction. Recent clinical trials have shown controversial results in recovering damaged cardiac tissue. New progress has shown that the underlying mechanisms of cell-based therapy relies more heavily on humoral and paracrine effects rather than on new tissue generation. However, studies have also reported the potential of new endothelial cell generation from BM cells. Thus, efforts have been made to identify cells having higher humoral or therapeutic effects as well as their surface markers. Specifically, BM-derived CD31(+) cells were isolated by a surface marker and demonstrated high angio-vasculogenic effects. This article will describe recent advances in the therapeutic use of BM-derived cells and the usefulness of CD31(+) cells. PMID: 21548739 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Accidental insertion of a percutaneous venovenous cannula into the persistent left superior vena cava of a patient undergoing liver transplantation. Can J Anaesth. 2011 May 7; Authors: Schreiber KL, Matsusaki T, Bane BC, Bermudez CA, Hilmi IA, Sakai T PURPOSE: Persistent left superior vena cava (PLSVC) is a rare congenital vascular abnormality found in 0.3% of the general population. We report herein a rare complication involving the accidental insertion of a large bore cannula into the PLSVC during liver transplantation (LT). CLINICAL FEATURES: A 63-yr-old man with primary sclerosing cholangitis presented for LT. Given the existence of a tunnelled dialysis catheter in the right internal jugular vein (IJV) and a triple lumen catheter via the left IJV, insertion of an 18 French cannula for venovenous bypass (VVB) was performed via the left IJV using the existing triple lumen cannula as a conduit for a guidewire. Upon initiation of VVB, profound systemic hypotension occurred, and liver transplantation was completed without the further use of VVB. A chest x-ray confirmed a malposition of the VVB cannula with a large left hemothorax. A mini-sternotomy was performed for removal of the VVB cannula, which was found to be inserted in the PLSVC. Retrospectively, the presence of PLSVC was not anticipated due to a normal superior vena cava and a left innominate vein, as revealed by the course of a pre-existing left internal jugular vein triple lumen catheter on a preoperative chest x-ray, and due to a normal-sized coronary sinus on preoperative echocardiography. CONCLUSION: Malpositioning of a venous cannula in a PLSVC should be anticipated as one of the potential complications of vascular access via the left internal jugular vein. PMID: 21553167 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Prospects of stem cell therapy in osteoarthritis. Regen Med. 2011 May;6(3):351-66 Authors: Roberts S, Genever P, McCaskie A, Bari CD Osteoarthritis is a common disorder in which there is not only extensive degeneration but also an aberrant attempt at repair in joints. Stem cell therapy could provide a permanent, biological solution, with all sources of stem cells (embryonic, fetal and adult) showing some degree of potential. Mesenchymal stromal/stem cells, however, appear to be the leading candidates because of their ability to be sourced from many or all joint tissues. They may also modulate the immune response of individuals, in a manner influenced by local factors. This biological behavior of stem cells renders the application of regulatory standardizations challenging in comparison to pharmaceutical therapies. However, this would not be an issue if endogenous stem cells were activated to effect repair of an arthritic joint. PMID: 21548740 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Cultured epithelial grafting using human amniotic membrane: The potential for using human amniotic epithelial cells as a cultured oral epithelium sheet. Arch Oral Biol. 2011 May 6; Authors: Koike T, Yasuo M, Shimane T, Kobayashi H, Nikaido T, Kurita H OBJECTIVE: Human amniotic cells are a valuable source of functional cells that can be used in various fields, including regenerative medicine and tissue engineering. The aim of this study was to investigate the utility of human amniotic epithelial (hAE) cells as a new cell source for culturing stratified epithelium sheets for intraoral grafting. METHODS: Enzymatically isolated hAE cells were submerged in a serum-free, low-calcium-supplemented MCDB 153 medium without a feeder layer. The hAE cells were seeded onto a Millicell cell culture plate insert and cultured while submerged in a high-calcium medium for 4 days. Then, they were cultured at an air-liquid interface for 3 weeks. Cultures of hAE cells proliferated at the air-liquid interface. RESULTS: After 3 weeks, the hAE cells cultivated using the air-liquid interface method lead to almost 10 continuous layers of stratified epithelium without parakeratinization or keratinization. It confirmed immunohistochemically that the presence of CK10/13 and Ki-67 positive cells were spread throughout almost all the epithelial layer, and that CK19 positive cells were expressed throughout the entire epithelial layer in the cultured hAE cell sheets. Cultured hAE cells sheets showed a staining pattern similar to that of uncultured oral mucosa: ZO-1 and occludin were located in the intercellular junctions throughout all the epithelial layers. It was suggested that the hAE sheets consisted of highly-active proliferating cells and undifferentiated cells, and had a barrier function. CONCLUSIONS: These results suggested that hAE cells may be a promising cell source for the development of stratified epithelium allograft sheets using a human cell strain. PMID: 21550584 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Enhanced functional properties of corneal epithelial cells by coculture with embryonic stem cells via the integrin β1-FAK-PI3K/Akt pathway. Int J Biochem Cell Biol. 2011 Apr 28; Authors: Zhou J, Chen F, Xiao J, Li C, Liu Y, Ding Y, Wan P, Wang X, Huang J, Wang Z Adult stem cells are important cell sources in regenerative medicine, but isolating them is technically challenging. This study employed a novel strategy to generate stem-like corneal epithelial cells and promote the functional properties of these cells by coculture with embryonic stem cells. The primary corneal epithelial cells were labelled with GFP and cocultured with embryonic stem cells in a transwell or by direct cell-cell contact. The embryonic stem cells were pre-transfected with HSV-tk-puro plasmids and became sensitive to ganciclovir. After 10 days of coculture, the corneal epithelial cells were isolated by treating the cultures with ganciclovir to kill the embryonic stem cells. The expression of stem cell-associated markers (ABCG2, p63) increased whereas the differentiation mark (Keratin 3) decreased in corneal epithelial cells isolated from the cocultures as evaluated by RT-PCR and flow cytometry. Their functional properties of corneal epithelial cells, including cell adhesion, migration and proliferation, were also enhanced. These cells could regenerate a functional stratified corneal epithelial equivalent but did not form tumors. Integrin β1, phosphorylated focal adhesion kinase and Akt were significantly upregulated in corneal epithelial cells. FAK Inhibitor 14 that suppressed the expression of phosphorylated focal adhesion kinase and Akt inhibited cell adhesion, migration and proliferation. LY294002 that suppressed phosphorylated Akt but not phosphorylated focal adhesion kinase inhibited cell proliferation but had no effect on cell adhesion or migration. These findings demonstrated that the functional properties of stem-like corneal epithelial cells were enhanced by cocultured embryonic stem cells via activation of the integrin β1-FAK-PI3K/Akt signalling pathway. PMID: 21550417 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [The cellular plasticity of human adipocytes]. Zhonghua Zheng Xing Wai Ke Za Zhi. 2011 Jan;27(1):51-7 Authors: Liao YJ, Gao JH, Lu F To explore the dedifferentiation phenomenon of human mature adipocytes cultured in vitro and to discuss the possibility of using dedifferentiation adipocytes (DA) as seed cells. PMID: 21548390 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Intramyocardial transplantation of undifferentiated rat induced pluripotent stem cells causes tumorigenesis in the heart. PLoS One. 2011;6(4):e19012 Authors: Zhang Y, Wang D, Chen M, Yang B, Zhang F, Cao K Induced pluripotent stem cells (iPSCs) are a novel candidate for use in cardiac stem cell therapy. However, their intrinsic tumorigenicity requires further investigation prior to use in a clinical setting. In this study we investigated whether undifferentiated iPSCs are tumorigenic after intramyocardial transplantation into immunocompetent allogeneic recipients. PMID: 21552563 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Prospects of stem cell therapy in osteoarthritis. Regen Med. 2011 May;6(3):351-66 Authors: Roberts S, Genever P, McCaskie A, Bari CD Osteoarthritis is a common disorder in which there is not only extensive degeneration but also an aberrant attempt at repair in joints. Stem cell therapy could provide a permanent, biological solution, with all sources of stem cells (embryonic, fetal and adult) showing some degree of potential. Mesenchymal stromal/stem cells, however, appear to be the leading candidates because of their ability to be sourced from many or all joint tissues. They may also modulate the immune response of individuals, in a manner influenced by local factors. This biological behavior of stem cells renders the application of regulatory standardizations challenging in comparison to pharmaceutical therapies. However, this would not be an issue if endogenous stem cells were activated to effect repair of an arthritic joint. PMID: 21548740 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Endothelialized biomaterials for tissue engineering applications in vivo. Trends Biotechnol. 2011 May 4; Authors: Khan OF, Sefton MV Rebuilding tissues involves the creation of a vasculature to supply nutrients and this in turn means that the endothelial cells (ECs) of the resulting endothelium must be a quiescent non-thrombogenic blood contacting surface. Such ECs are deployed on biomaterials that are composed of natural materials such as extracellular matrix proteins or synthetic polymers in the form of vascular grafts or tissue-engineered constructs. Because EC function is influenced by their origin, biomaterial surface chemistry and hemodynamics, these issues must be considered to optimize implant performance. In this review, we examine the recent in vivo use of endothelialized biomaterials and discuss the fundamental issues that must be considered when engineering functional vasculature. PMID: 21549438 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Impact of Scaffold Micro and Macro Architecture on Schwann Cell Proliferation under Dynamic Conditions in a Rotating Wall Vessel Bioreactor. Mater Sci Eng C Mater Biol Appl. 2011 Jan 1;31(1):22-29 Authors: Valmikinathan CM, Hoffman J, Yu X Over the last decade tissue engineering has emerged as a powerful alternative to regenerate lost tissues owing to trauma or tumor. Evidence shows that Schwann cell containing scaffolds have improved performance in vivo as compared to scaffolds that depend on cellularization post implantation. However, owing to limited supply of cells from the patients themselves, several approaches have been taken to enhance cell proliferation rates to produce complete and uniform cellularization of scaffolds. The most common approach is the application of a bioreactor to enhance cell proliferation rate and therefore reduce the time needed to obtain sufficiently significant number of glial cells, prior to implantation.In this study, we show the application of a rotating wall bioreactor system for studying Schwann cell proliferation on nanofibrous spiral shaped scaffolds, prepared by solvent casting and salt leaching techniques. The scaffolds were fabricated from polycaprolactone (PCL), which has ideal mechanical properties and upon degradation does not produce acidic byproducts. The spiral scaffolds were coated with aligned or random nanofibers, produced by electrospinning, to provide a substrate that mimics the native extracellular matrix and the essential contact guidance cues.At the 4 day time point, an enhanced rate of cell proliferation was observed on the open structured nanofibrous spiral scaffolds in a rotating wall bioreactor, as compared to static culture conditions. However, the cell proliferation rate on the other contemporary scaffolds architectures such as the tubular and cylindrical scaffolds show reduced cell proliferation in the bioreactor as compared to static conditions, at the same time point. Moreover, the rotating wall bioreactor does not alter the orientation or the phenotype of the Schwann cells on the aligned nanofiber containing scaffolds, wherein, the cells remain aligned along the length of the scaffolds. Therefore, these open structured spiral scaffolds pre-cultured with Schwann cells, in bioreactors could potentially shorten the time needed for grafts for peripheral nerve regeneration. PMID: 21552367 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Reconstructive urethroplasty using porcine acellular matrix (SIS): evolution of the grafting technique and results of 10-year experience.] Urologia. 2011 Apr 28; Authors: Mantovani F, Tondelli E, Cozzi G, Abed El Rahman D, Spinelli MG, Oliva I, Finkelberg E, Talso M, Varisco D, Maggioni A, Rocco F Introduction. Long tract urethral reconstruction still has no other resolution than two-stage techniques or graft and flap procedures, that are neither simple nor trouble-free. Tissue engineering simplifies this surgery using porcine acellular matrix, obtained from small intestine submucosa (SIS): thin but strong, ready for grafting, it is not immunogenic, being deprived of cells. It is a biological bridge for reconstruction, promoting the regeneration of surrounding tissue. We report our experience using SIS for urethroplasty. Materials and Methods. After coronal or perineal-scrotal incision and penile degloving, the urethra is rotated of 180° and opened through the entire restricted tract. The graft is sutured dorsally and reinforced by the contact with the cavernous bodies to prevent pouching. From 1999 to 2005 we performed this grafting procedure in 36 men and 4 women. Afterwards, 16 more surgeries performed were with direct ventral graft procedure, without urethra isolation and rotation, with worthy simplification. Results. A 10-year follow-up shows satisfactory urodynamic and subjective outcomes for both procedures, assessed by voiding urethrography, uroflowmetry, International Prostate Symptom Score, and Quality of Life perception. At urethroscopy the graft appears completely homogeneous to the native tissue, as confirmed by the histological examination. The ventral direct graft represents the more consistent innovation: we did not observe pouching and the results remained effective. For penile urethra, in a few patients, periodic dilatations were necessary. Conclusions. SIS can be considered as an alternative to more difficult grafting procedures, which are probably no more indispensable in urethral enlargement, even for critical strictures. PMID: 21553386 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Flexor Tendon Tissue Engineering: Acellularization of Human Flexor Tendons with Preservation of Biomechanical Properties and Biocompatibility. Tissue Eng Part C Methods. 2011 May 6; Authors: Pridgen BC, Woon CY, Kim M, Thorfinn J, Lindsey D, Pham H, Chang J Objective: Acellular human tendons are a candidate scaffold for tissue engineering flexor tendons of the hand. This study compared acellularization methods and their compatibility with allogeneic human cells. Method: Human flexor tendons were pretreated with 0.1% ethylenediaminetetracetic acid (EDTA) for 4 h followed by 24 h treatments of 1% Triton X-100, 1% tri(n-butyl)phosphate, or 0.1% or 1% sodium dodecyl sulfate (SDS) in 0.1% EDTA. Outcomes were assessed histologically by hematoxylin and eosin and SYTO green fluorescent nucleic acid stains and biochemically by a QIAGEN DNeasy kit, Sircol collagen assay, and 1,9 dimethylmethylene blue glycosaminoglycan assay. Mechanical data were collected using a Materials Testing System to pull to failure tendons acellularized with 0.1% SDS. Acellularized tendons were re-seeded in a suspension of human dermal fibroblasts. Attachment of viable cells to acellularized tendon was assessed biochemically by a cell viability assay and histologically by a live/dead stain. Data are reported as mean±standard deviation. Result: Compared with the DNA content of fresh tendons (551±212 ng DNA/mg tendon), only SDS treatments significantly decreased DNA content (1% SDS [202.8±37.4 ng DNA/mg dry weight tendon]; 0.1% SDS [189±104 ng DNA/mg tendon]). These findings were confirmed by histology. There was no decrease in glycosaminoglycans or collagen following acellularization with SDS. There was no difference in the ultimate tensile stress (55.3±19.2 [fresh] vs. 51.5±6.9 [0.1% SDS] MPa). Re-seeded tendons demonstrated attachment of viable cells to the tendon surface using a viability assay and histology. Conclusion: Human flexor tendons were acellularized with 0.1% SDS in 0.1% EDTA for 24 h with preservation of mechanical properties. Preservation of collagen and glycoaminoglycans and re-seeding with human cells suggest that this scaffold is biocompatible. This will provide a promising scaffold for future human flexor tendon tissue engineering studies to further assess biocompatibility through cell proliferation and in vivo studies. PMID: 21548795 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Confined Diffusion in Periodic Porous Nanostructures. ACS Nano. 2011 May 6; Authors: Raccis R, Nikoubashman A, Retsch M, Jonas U, Koynov K, Butt HJ, Likos CN, Fytas G We performed fluorescence correlation spectroscopy measurements to assess the long-time self diffusion of a variety of spherical tracer particles in periodic porous nanostructures. Inverse opal structures with variable cavity sizes and openings in the nanometer domain were employed as model system. We obtained both the exponent of the scaling relation between mean-square displacement and time, and the slowdown factors due to the periodic confinement for a number of particle sizes and confining characteristics. In addition, we carried out Brownian dynamics simulations to model the experimental conditions. Good agreement between experimental and simulation results has been obtained regarding the slowdown factor. Fickian diffusion is predicted and seen in almost all experimental systems, while apparent non-Fickian exponents that show up for two strongly confined systems are attributed to polydispersity of the cavity openings. The utility of confining periodic porous nanostructures holds promise towards understanding of constrained diffusion with a wide range of applications ranging from water purification and drug delivery to tissue engineering. PMID: 21548605 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Current strategies for osteochondral regeneration: from stem cells to pre-clinical approaches. Curr Opin Biotechnol. 2011 May 6; Authors: Rodrigues MT, Gomes ME, Reis RL Damaged cartilage tissue has no functional replacement alternatives and current therapies for bone injury treatment are far from being the ideal solutions emphasizing an urgent need for alternative therapeutic approaches for osteochondral (OC) regeneration. The tissue engineering field provides new possibilities for therapeutics and regeneration in rheumatology and orthopaedics, holding the potential for improving the quality of life of millions of patients by exploring new strategies towards the development of biological substitutes to maintain, repair and improve OC tissue function. Numerous studies have focused on the development of distinct tissue engineering strategies that could result in promising solutions for this delicate interface. In order to outperform currently used methods, novel tissue engineering approaches propose, for example, the design of multi-layered scaffolds, the use of stem cells, bioreactors or the combination of clinical techniques. PMID: 21550794 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Cultured epithelial grafting using human amniotic membrane: The potential for using human amniotic epithelial cells as a cultured oral epithelium sheet. Arch Oral Biol. 2011 May 6; Authors: Koike T, Yasuo M, Shimane T, Kobayashi H, Nikaido T, Kurita H OBJECTIVE: Human amniotic cells are a valuable source of functional cells that can be used in various fields, including regenerative medicine and tissue engineering. The aim of this study was to investigate the utility of human amniotic epithelial (hAE) cells as a new cell source for culturing stratified epithelium sheets for intraoral grafting. METHODS: Enzymatically isolated hAE cells were submerged in a serum-free, low-calcium-supplemented MCDB 153 medium without a feeder layer. The hAE cells were seeded onto a Millicell cell culture plate insert and cultured while submerged in a high-calcium medium for 4 days. Then, they were cultured at an air-liquid interface for 3 weeks. Cultures of hAE cells proliferated at the air-liquid interface. RESULTS: After 3 weeks, the hAE cells cultivated using the air-liquid interface method lead to almost 10 continuous layers of stratified epithelium without parakeratinization or keratinization. It confirmed immunohistochemically that the presence of CK10/13 and Ki-67 positive cells were spread throughout almost all the epithelial layer, and that CK19 positive cells were expressed throughout the entire epithelial layer in the cultured hAE cell sheets. Cultured hAE cells sheets showed a staining pattern similar to that of uncultured oral mucosa: ZO-1 and occludin were located in the intercellular junctions throughout all the epithelial layers. It was suggested that the hAE sheets consisted of highly-active proliferating cells and undifferentiated cells, and had a barrier function. CONCLUSIONS: These results suggested that hAE cells may be a promising cell source for the development of stratified epithelium allograft sheets using a human cell strain. PMID: 21550584 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cell differentiation to epidermal lineages on electrospun nanofibrous substrates for skin tissue engineering. Acta Biomater. 2011 Apr 23; Authors: Jin G, Prabhakaran MP, Ramakrishna S Bone marrow (BM) mesenchymal stem cells (MSC) capable of differentiating along the epidermal lineage on engineered nanofibrous scaffolds have great potential for bionanomaterial-cell transplantation therapy of skin wounds. MSC have been the focus of many tissue engineering studies, mainly because of their multipotential properties. We investigated the potential of human BM-derived MSC for epidermal cell differentiation in vitro on electrospun collagen/poly(l-lactic acid)-co-poly(3-caprolactone) (Coll/PLLCL) nanofibrous scaffolds. PLLCL and Coll/PLLCL nanofibrous scaffolds were fabricated by an electrospinning process and their chemical and mechanical characterization carried out by scanning electron microscopy (SEM), water contact angle determination, Fourier transform infrared spectroscopy, and tensile testing. The differentiation of MSC was carried out using epidermis inducing factors, including epidermal growth factor (EGF) and 1,25-dihydroxyvitamin D(3), in culture medium. The proliferation of MSC evaluated by cell proliferation assay showed that the number of cells grown on Coll/PLLCL nanofibrous scaffolds was significantly higher than those on PLLCL scaffolds. The SEM results showed that MSC differentiated on Coll/PLLCL nanofibrous scaffolds showed a round keratinocyte morphology and expressed keratin 10, filaggrin and partial involucrin protein by immunofluorescent microscopic studies. The interaction of MSC and nanofibers was studied and we concluded that the electrospun Coll/PLLCL nanofibers could mimic the native skin extracellular matrix environment and are promising substrates for advanced skin tissue engineering. Our studies on the differentiation of MSC along the epidermal lineage on nanofibrous scaffolds suggest their potential application in skin regeneration without regional differentiation. PMID: 21550425 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Heparin-chitosan-coated acellular bone matrix enhances perfusion of blood and vascularization in bone tissue engineering scaffolds. Tissue Eng Part A. 2011 May 7; Authors: Sun XJ, Peng W, Ren ML, Zhang SC, Zhang WG, Zhang LY, Xiao K, Yang Z, Wang ZG, Zhang B, Wang J Currently, the main hurdle in the tissue engineering field is how to provide sufficient blood supply to grafted tissue substitutes in the early post-transplanted period. For three-dimensional (3-D), cell-dense, thick tissues to survive after transplantation, treatments are required for hypoxia, nutrient insufficiency, and the accumulation of waste products. In this study, a biomacromolecular layer-by-layer coating process of chitosan/heparin onto a decellularized extracellular bone matrix was designed to accelerate the blood perfusion and re-endothelialization process. The results of in vitro measurements of the activated partial thromboplastin time (APTT) supported the theory that the combination of chitosan and heparin could bring both anticoagulation and hemocompatibility to the scaffold. A rabbit bone defect model was established for further evaluation of the application of this kind of surface-modified scaffold in vivo. The final results of CT perfusion imaging and histological examination proved that this facile coating approach could significantly promote blood perfusion and re-endothelialization in the early post-transplanted period compared with an acellular bone matrix (ACBM) due to its much improved anticoagulation property. PMID: 21548841 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Prospects of stem cell therapy in osteoarthritis. Regen Med. 2011 May;6(3):351-66 Authors: Roberts S, Genever P, McCaskie A, Bari CD Osteoarthritis is a common disorder in which there is not only extensive degeneration but also an aberrant attempt at repair in joints. Stem cell therapy could provide a permanent, biological solution, with all sources of stem cells (embryonic, fetal and adult) showing some degree of potential. Mesenchymal stromal/stem cells, however, appear to be the leading candidates because of their ability to be sourced from many or all joint tissues. They may also modulate the immune response of individuals, in a manner influenced by local factors. This biological behavior of stem cells renders the application of regulatory standardizations challenging in comparison to pharmaceutical therapies. However, this would not be an issue if endogenous stem cells were activated to effect repair of an arthritic joint. PMID: 21548740 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Living bacterial sacrificial porogens to engineer decellularized porous scaffolds. PLoS One. 2011;6(4):e19344 Authors: Xu F, Sridharan B, Durmus NG, Wang S, Yavuz AS, Gurkan UA, Demirci U Decellularization and cellularization of organs have emerged as disruptive methods in tissue engineering and regenerative medicine. Porous hydrogel scaffolds have widespread applications in tissue engineering, regenerative medicine and drug discovery as viable tissue mimics. However, the existing hydrogel fabrication techniques suffer from limited control over pore interconnectivity, density and size, which leads to inefficient nutrient and oxygen transport to cells embedded in the scaffolds. Here, we demonstrated an innovative approach to develop a new platform for tissue engineered constructs using live bacteria as sacrificial porogens. E.coli were patterned and cultured in an interconnected three-dimensional (3D) hydrogel network. The growing bacteria created interconnected micropores and microchannels. Then, the scafold was decellularized, and bacteria were eliminated from the scaffold through lysing and washing steps. This 3D porous network method combined with bioprinting has the potential to be broadly applicable and compatible with tissue specific applications allowing seeding of stem cells and other cell types. PMID: 21552485 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Development of fluorapatite cement for dental enamel defects repair. J Mater Sci Mater Med. 2011 May 7; Authors: Wei J, Wang J, Shan W, Liu X, Ma J, Liu C, Fang J, Wei S In order to restore the badly carious lesion of human dental enamel, a crystalline paste of fluoride substituted apatite cement was synthesized by using the mixture of tetracalcium phosphate (TTCP), dicalcium phosphate anhydrous (DCPA) and ammonium fluoride. The apatite cement paste could be directly filled into the enamel defects (cavities) to repair damaged dental enamel. The results indicated that the hardened cement was fluorapatite [Ca(10)(PO(4))(6)F(2), FA] with calcium to phosphorus atom molar ratio (Ca/P) of 1.67 and Ca/F ratio of 5. The solubility of FA cement in Tris-HCl solution (pH = 5) was slightly lower than the natural enamel, indicating the FA cement was much insensitive to the weakly acidic solutions. The FA cement was tightly combined with the enamel surface, and there was no obvious difference of the hardness between the FA cement and natural enamel. The extracts of FA cement caused no cytotoxicity on L929 cells, which satisfied the relevant criterion on dental biomaterials, revealing good cytocompatibility. In addition, the results showed that the FA cement had good mechanical strength, hydrophilicity, and anti-bacterial adhesion properties. The study suggested that using FA cement was simple and promising approach to effectively and conveniently restore enamel defects. PMID: 21553155 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Preparation, characterization and antimicrobial activity of a bio-composite scaffold containing chitosan/nano-hydroxyapatite/nano-silver for bone tissue engineering. Int J Biol Macromol. 2011 Apr 28; Authors: Saravanan S, Nethala S, Pattnaik S, Tripathi A, Moorthi A, Selvamurugan N In this study, a bio-composite scaffold containing chitosan/nano-hydroxyapatite/nano-silver particles (CS/nHAp/nAg) was developed by freeze drying technique, followed by introduction of silver ions in controlled amount through reduction phenomenon by functional groups of chitosan. The scaffolds were characterized using SEM, FT-IR, XRD, swelling, and biodegradation studies. The testing of the prepared scaffolds with Gram-positive and Gram-negative bacterial strains showed antibacterial activity. The scaffold materials were also found to be non-toxic to rat osteoprogenitor cells and human osteosarcoma cell line. Thus, these results suggested that CS/nHAp/nAg bio-composite scaffolds have the potential in controlling implant associated bacterial infection during reconstructive surgery of bone. PMID: 21549747 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Non-mulberry silk sericin/poly (vinyl alcohol) hydrogel matrices for potential biotechnological applications. Int J Biol Macromol. 2011 Apr 28; Authors: Mandal BB, Ghosh B, Kundu SC This study is a report on a novel biopolymeric matrix fabricated by chemically cross-linking poly (vinyl alcohol) with silk sericin protein obtained from cocoons of the tropical tasar silkworm Antheraea mylitta. Glutaraldehyde was used as a cross-linking agent with hydrochloric acid acting as an initiator. The matrices were biophysically characterized and the cytocompatibility of the matrices was evaluated for their suitability as biomaterials. The surface morphology was assessed using atomic force microscopy while the changes taking place after cross-linking were confirmed by Fourier transform infrared spectroscopy. The enhanced thermal stability of the constructs was assessed by thermogravimetric and differential scanning calorimetry. Fourier transform infrared spectroscopy analysis showed that sericin was chemically cross-linked with poly (vinyl alcohol) using glutaraldehyde. Silk sericin protein demonstrated a favorable effect on animal cell culture by successfully improving the adhering and spreading of cells on the poorly adhering surface of poly (vinyl alcohol). Confocal microscopy revealed cell spreading and actin filament development in sericin/poly (vinyl alcohol) hydrogel matrices. These findings prove the potential of non-mulberry silk sericin/poly (vinyl alcohol) hydrogel matrices to be used as biocompatible and biopolymeric material for tissue-engineering and biotechnological applications. PMID: 21549749 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The effect of anisotropic collagen-GAG scaffolds and growth factor supplementation on tendon cell recruitment, alignment, and metabolic activity. Biomaterials. 2011 May 6; Authors: Caliari SR, Harley BA Current surgical and tissue engineering approaches for treating tendon injuries have shown limited success, suggesting the need for new biomaterial strategies. Here we describe the development of an anisotropic collagen-glycosaminoglycan (CG) scaffold and use of growth factor supplementation strategies to create a 3D platform for tendon tissue engineering. We fabricated cylindrical CG scaffolds with aligned tracks of ellipsoidal pores that mimic the native physiology of tendon by incorporating a directional solidification step into a conventional lyophilization strategy. By modifying the freezing temperature, we created a homologous series of aligned CG scaffolds with constant relative density and degree of anisotropy but a range of pore sizes (55-243 μm). Equine tendon cells showed greater levels of attachment, metabolic activity, and alignment as well as less cell-mediated scaffold contraction, when cultured in anisotropic scaffolds compared to an isotropic CG scaffold control. The anisotropic CG scaffolds also provided critical contact guidance cues for cell alignment. While tendon cells were randomly oriented in the isotropic control scaffold and the transverse (unaligned) plane of the anisotropic scaffolds, significant cell alignment was observed in the direction of the contact guidance cues in the longitudinal plane of the anisotropic scaffolds. Scaffold pore size was found to significantly influence tendon cell viability, proliferation, penetration into the scaffold, and metabolic activity in a manner predicted by cellular solids arguments. Finally, the addition of the growth factors PDGF-BB and IGF-1 to aligned CG scaffolds was found to enhance tendon cell motility, viability, and metabolic activity in dose-dependent manners. This work suggests a composite strategy for developing bioactive, 3D material systems for tendon tissue engineering. PMID: 21550653 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The quest for an optimized protocol for whole heart decellularization: A comparison of three popular and a novel decellularization technique and their diverse effects on crucial extracellular matrix qualities. Tissue Eng Part C Methods. 2011 May 6; Authors: Akhyari P, Aubin H, Gwanmesia P, Barth M, Hoffmann S, Huelsmann J, Preuss KH, Lichtenberg A Decellularized cardiac ECM has been introduced as a template for cardiac tissue engineering, providing the advantages of a prevascularized scaffold that mimicks native micro- and macroarchitecture to a degree difficult to achieve with synthetic materials. Nonetheless, the decellularization protocols used to create acellular myocardial scaffolds vary widely throughout the literature. In this study we performed a direct comparison of three previously described protocols while introducing and evaluating a novel, specifically developed fourth protocol, by decellularizing whole rat hearts through software-controlled automatic coronary perfusion. Although all protocols preserved the macroarchitecture of the hearts and all resulting scaffolds could successfully be reseeded with myocytes, assessing their biocompatibility for 3D in vitro studies, we found striking differences concerning the microcomposition of the ECM-scaffolds on a histological and biochemical level. While laminin could still be detected in all groups, other crucial ECM-components, like elastin and collagen IV, were completely removed by at least one of the protocols. Further, only three protocols maintained a GAG-content comparable to native tissue, while the remaining DNA-content within the ECM varied highly throughout all four tested protocols. This study showed that the degree of acellularity and resulting ECM composition of decellularized myocardial scaffolds strongly differ depending on the decellularization protocol. PMID: 21548726 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Periosteum as a source of mesenchymal stem cells: the effects of TGF-β3 on chondrogenesis. Clinics (Sao Paulo). 2011;66(3):487-92 Authors: Mara CS, Sartori AR, Duarte AS, Andrade AL, Pedro MA, Coimbra IB Numerous experimental efforts have been undertaken to induce the healing of lesions within articular cartilage by re-establishing competent repair tissue. Adult mesenchymal stem cells have attracted attention as a source of cells for cartilage tissue engineering. The purpose of this study was to investigate chondrogenesis employing periosteal mesenchymal cells. PMID: 21552678 [PubMed - in process] | | | | | | | | | |  | |  | |  |
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