|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | The effect of two and three dimensional cell culture on the chondrogenic potential of human adipose-derived mesenchymal stem cells after subcutaneous transplantation with an injectable hydrogel. Cell Transplant. 2011 Feb 3; Authors: Merceron C, Portron S, Masson M, Lesoeur J, Fellah BH, Gauthier O, Geffroy O, Weiss P, Guicheux J, Vinatier C Articular cartilage is an avascular tissue composed of chondrocytes, a unique cell type responsible for abundant matrix synthesis and maintenance. When damaged, it never heals spontaneously under physiological circumstances. Therefore, the delivery of mesenchymal stem cells using hydrogel has been considered for cartilage repair. This study aims at investigating the influence of in vitro chondrogenic differentiation of human adipose tissue-derived stem cells (hATSC) on in vivo cartilage formation when associated with a cellulose-based self-setting hydrogel (Si-HPMC). hATSC were characterized for their proliferation, surface marker expression and multipotency. The in vitro chondrogenic potential of hATSC cultured within Si-HPMC in control or chondrogenic medium was evaluated by measuring COL2A1 and ACAN expression by real time PCR. Alcian blue and type II collagen staining were also performed. To determine whether in vitro chondrogenically-differentiated hATSC may give rise to cartilage in vivo, cells differentiated as a monolayer or in pellets were finally associated with Si-HPMC and implanted subcutaneously into nude mice. Cartilage formation was assessed histologically by alcian blue and type II collagen staining. Our data demonstrate that hATSC exhibited proliferation and self-renewal. hATSC also expressed typical stem cell surface markers and were able to differentiate towards the adipo- osteo- and chondrogenic lineages. Real time-PCR and histological analysis indicated that Si-HPMC enabled chondrogenic differentiation of hATSC in inductive medium, as demonstrated by increased expression of chondrogenic markers. In addition, histological analysis of implants showed that chondrogenically-differentiated hATSC (monolayers or pellets), have the ability to form cartilaginous tissue, as indicated by the presence of sulphated-glycosaminoglycans and type II collagen. This study therefore suggests that an in vitro induction of hATSC in 2D was sufficient to obtain cartilaginous tissue formation in vivo. Si-HPMC associated with autologous hATSC could thus be a significant tool for regenerative medicine in the context of cartilage damage. PMID: 21294960 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Histone deacetylase regulates high mobility group A2-targeting microRNAs in human cord blood-derived multipotent stem cell aging. Cell Mol Life Sci. 2011 Jan;68(2):325-36 Authors: Lee S, Jung JW, Park SB, Roh K, Lee SY, Kim JH, Kang SK, Kang KS Cellular senescence involves a reduction in adult stem cell self-renewal, and epigenetic regulation of gene expression is one of the main underlying mechanisms. Here, we observed that the cellular senescence of human umbilical cord blood-derived multipotent stem cells (hUCB-MSCs) caused by inhibition of histone deacetylase (HDAC) activity leads to down-regulation of high mobility group A2 (HMGA2) and, on the contrary, to up-regulation of p16(INK)⁴(A), p21(CIP)¹(/WAF)¹ and p27(KIP)¹. We found that let-7a1, let-7d, let-7f1, miR-23a, miR-26a and miR-30a were increased during replicative and HDAC inhibitor-mediated senescence of hUCB-MSCs by microRNA microarray and real-time quantitative PCR. Furthermore, the configurations of chromatins beading on these miRNAs were prone to transcriptional activation during HDAC inhibitor-mediated senescence. We confirmed that miR-23a, miR-26a and miR-30a inhibit HMGA2 to accelerate the progress of senescence. These findings suggest that HDACs may play important roles in cellular senescence by regulating the expression of miRNAs that target HMGA2 through histone modification. PMID: 20652617 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Mechanical phenotyping of stem cells. Theriogenology. 2011 Feb 3; Authors: Keefer CL, Desai JP Elasticity and visco-elasticity are mechanical properties of cells which directly reflect cellular composition, internal structure (cytoskeleton), and external interactions (cell-cell and/or cell-surface). A variety of techniques involving probing, pulling, or deforming cells have been used to characterize these mechanical properties. With continuing advances in the technology, it may be possible to establish mechanical phenotypes that can be used to identify cells at specific points of differentiation and dedifferentiation with direct applications to regenerative medicine, therapeutics, and diagnostics. PMID: 21295841 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Synthesis of Temperature-Responsive Dextran-MA/PNIPAAm Particles for Controlled Drug Delivery Using Superhydrophobic Surfaces. Pharm Res. 2011 Feb 5; Authors: Lima AC, Song W, Blanco-Fernandez B, Alvarez-Lorenzo C, Mano JF PURPOSE: To implement a bioinspired methodology using superhydrophobic surfaces suitable for producing smart hydrogel beads in which the bioactive substance is introduced in the particles during their formation. METHODS: Several superhydrophobic surfaces, including polystyrene, aluminum and copper, were prepared. Polymeric solutions composed by photo-crosslinked dextran-methacrylated and thermal responsive poly(N-isopropylacrylamide) mixed with a protein (insulin or albumin) were dropped on the superhydrophobic surfaces, and the obtained millimetric spheres were hardened in a dry environment under UV light. RESULTS: Spherical and non-sticky hydrogels particles were formed in few minutes on the superhydrophobic surfaces. The proteins included in the liquid formulation were homogeneously distributed in the particle network. The particles exhibited temperature-sensitive swelling, porosity and protein release rate, with the responsiveness tunable by the dextran-MA/PNIPAAm weight ratio. CONCLUSIONS: The proposed method permitted the preparation of smart hydrogel particles in one step with almost 100% encapsulation yield. The temperature-sensitive release profiles suggest that the obtained spherical-shaped biomaterials are suitable as protein carriers. These stimuli-responsive beads could have potential to be used in pharmaceutical or other biomedical applications, including tissue engineering and regenerative medicine. PMID: 21298327 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Spider silk proteins: recent advances in recombinant production, structure-function relationships and biomedical applications. Cell Mol Life Sci. 2011 Jan;68(2):169-84 Authors: Rising A, Widhe M, Johansson J, Hedhammar M Spider dragline silk is an outstanding material made up of unique proteins-spidroins. Analysis of the amino acid sequences of full-length spidroins reveals a tripartite composition: an N-terminal non-repetitive domain, a highly repetitive central part composed of approximately 100 polyalanine/glycine rich co-segments and a C-terminal non-repetitive domain. Recent molecular data on the terminal domains suggest that these have different functions. The composite nature of spidroins allows for recombinant production of individual and combined regions. Miniaturized spidroins designed by linking the terminal domains with a limited number of repetitive segments recapitulate the properties of native spidroins to a surprisingly large extent, provided that they are produced and isolated in a manner that retains water solubility until fibre formation is triggered. Biocompatibility studies in cell culture or in vivo of native and recombinant spider silk indicate that they are surprisingly well tolerated, suggesting that recombinant spider silk has potential for biomedical applications. PMID: 20668909 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Stage-Specific Optimization of Activin/Nodal and BMP Signaling Promotes Cardiac Differentiation of Mouse and Human Pluripotent Stem Cell Lines. Cell Stem Cell. 2011 Feb 4;8(2):228-40 Authors: Kattman SJ, Witty AD, Gagliardi M, Dubois NC, Niapour M, Hotta A, Ellis J, Keller G Efficient differentiation of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) to a variety of lineages requires step-wise approaches replicating the key commitment stages found during embryonic development. Here we show that expression of PdgfR-α segregates mouse ESC-derived Flk-1 mesoderm into Flk-1(+)PdgfR-α(+) cardiac and Flk-1(+)PdgfR-α(-) hematopoietic subpopulations. By monitoring Flk-1 and PdgfR-α expression, we found that specification of cardiac mesoderm and cardiomyocytes is determined by remarkably small changes in levels of Activin/Nodal and BMP signaling. Translation to human ESCs and iPSCs revealed that the emergence of cardiac mesoderm could also be monitored by coexpression of KDR and PDGFR-α and that this process was similarly dependent on optimal levels of Activin/Nodal and BMP signaling. Importantly, we found that individual mouse and human pluripotent stem cell lines require optimization of these signaling pathways for efficient cardiac differentiation, illustrating a principle that may well apply in other contexts. PMID: 21295278 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | An overview of tissue and whole organ decellularization processes. Biomaterials. 2011 Feb 4; Authors: Crapo PM, Gilbert TW, Badylak SF Biologic scaffold materials composed of extracellular matrix (ECM) are typically derived by processes that involve decellularization of tissues or organs. Preservation of the complex composition and three-dimensional ultrastructure of the ECM is highly desirable but it is recognized that all methods of decellularization result in disruption of the architecture and potential loss of surface structure and composition. Physical methods and chemical and biologic agents are used in combination to lyse cells, followed by rinsing to remove cell remnants. Effective decellularization methodology is dictated by factors such as tissue density and organization, geometric and biologic properties desired for the end product, and the targeted clinical application. Tissue decellularization with preservation of ECM integrity and bioactivity can be optimized by making educated decisions regarding the agents and techniques utilized during processing. An overview of decellularization methods, their effect upon resulting ECM structure and composition, and recently described perfusion techniques for whole organ decellularization techniques are presented herein. PMID: 21296410 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | TGF{beta}2 Treatment Enhances Cytoprotective Factors Released from Embryonic Stem Cells and Inhibits Apoptosis in the Infarcted Myocardium. Am J Physiol Heart Circ Physiol. 2011 Feb 4; Authors: Singla DK, Singla RD, Lamm S, Glass C We investigated whether factors released from mouse embryonic stem (ES) cells primed with and without TGFβ2 inhibit IAA and H(2)O(2) induced apoptosis in the cell culture system as well as following transplantation in the infarcted heart. We generated conditioned medium (CM) from ES cells primed with and without TGFβ2, and determined their effects on IAA and H(2)O(2) induced apoptosis in H9c2 cells. We also transplanted both ES-CMs in the infarcted heart to determine the effects on apoptosis and cardiac function post-MI at D1 and D14. TUNEL staining, apoptotic ELISA, and cell viability data demonstrated significantly (p<0.05) reduced apoptosis with ES-CM compared with controls in both cell culture models. Moreover, TGFβ2 primed ES-CM (T-ES-CM) demonstrated enhanced beneficial effects with further reduced (p<0.05) apoptosis compared with ES-CM, suggesting there may be a presence of additional cytoprotective released factors following TGFβ2 treatment. Next, our in vivo apoptosis data suggests significant decrease in apoptosis with both ES-CMs compared with MI at D1 and D14. Notably, T-ES-CM demonstrated significant (p<0.05) inhibition of apoptosis and fibrosis with improved cardiac function compared with ES-CM at D14, whereas no such effects were observed at D1. Next, we confirmed that apoptosis is mediated through pro-survival pathway, Akt. Moreover, we determined that following TGFβ2 treatment, there was a 2-5 fold increase in cytoprotective released factors (interleukin-10, stem cell factor, TIMP-1 and VEGF) in the T-ES-CM compared to ES-CM. In conclusion, we suggest that factors released from ES cells with and without TGFβ2 treatment contain anti-apoptotic factors that inhibit apoptosis in vitro and in vivo. We also suggest that T-ES-CM demonstrate additional beneficial effects which provide useful information for future therapeutic applications in regenerative medicine. PMID: 21297031 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Synthesis and characterization of photocrosslinkable gelatin and silk fibroin interpenetrating polymer network hydrogels. Acta Biomater. 2011 Feb 1; Authors: Xiao W, He J, Nichol JW, Wang L, Hutson CB, Wang B, Du Y, Fan H, Khademhosseini A To effectively repair or replace damaged tissues, it is necessary to design scaffolds with tunable structural and biomechanical properties that closely mimic the host tissue. In this paper, we describe a newly synthesized photocrosslinkable interpenetrating polymer network (IPN) hydrogel based on gelatin methacrylate (GelMA) and silk fibroin (SF) formed by sequential polymerization, which possesses tunable structural and biological properties. Experimental results revealed that IPNs, where both the GelMA and SF were independently crosslinked in interpenetrating networks, demonstrated a lower swelling ratio, higher compressive modulus and lower degradation rate as compared to the GelMA and semi-IPN hydrogels, where only GelMA was crosslinked. These differences were likely caused by a higher degree of overall crosslinking due to the presence of crystallized SF in the IPN hydrogels. NIH-3T3 fibroblasts readily attached to, spread, and proliferated on the surface of IPN hydrogels as demonstrated by F-actin staining and analysis of mitochondrial activity (MTT). In addition, photolithography combined with lyophilization techniques was used to fabricate 3D micropatterned and porous micro-scaffolds from GelMA-SF IPN hydrogels, furthering their versatility for use in various microscale tissue engineering applications. Overall, this study introduces a class of photocrosslinkable, mechanically robust and tunable IPN hydrogels that could be useful for various tissue engineering and regenerative medicine applications. PMID: 21295165 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Antibiotic-Releasing Porous Polymethylmethacrylate/Gelatin/Antibiotic Constructs for Craniofacial Tissue Engineering. J Control Release. 2011 Feb 1; Authors: Shi M, Kretlow JD, Spicer PP, Tabata Y, Demian N, Wong ME, Kasper FK, Mikos AG An antibiotic-releasing porous polymethylmethacrylate (PMMA) construct was developed to maintain the bony space and prime the wound site in the initial step of a two-stage regenerative medicine approach toward reconstructing significant bony or composite craniofacial tissue defects. Porous polymethylmethacrylate (PMMA) constructs incorporating gelatin microparticles (GMPs) were fabricated by the sequential assembly of GMPs, the antibiotic colistin, and a clinically used bone cement formulation of PMMA powder and methylmethacrylate liquid. PMMA/gelatin/antibiotic constructs with varying gelatin incorporation and drug content were investigated to elucidate the relationship between material composition and construct properties (porosity and drug release kinetics). The porosity of PMMA/gelatin/antibiotic constructs ranged between 7.6±1.8-38.4±1.4% depending on the amount of gelatin incorporated and the drug solution added for gelatin swelling. The constructs released colistin over 10 or 14 days with an average release rate per day above 10 μg/ml. The porosity and in vitro colistin release kinetics of PMMA/gelatin/antibiotic constructs were tuned by varying the material composition and fabrication parameters. This study demonstrates the potential of gelatin-incorporating PMMA constructs as a functional space maintainer for both promoting tissue healing/coverage and addressing local infections, enabling better long-term success of the definitive regenerated tissue construct. PMID: 21295086 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Endothelial Cells in Co-culture Enhance Embryonic Stem Cell Differentiation to Pancreatic Progenitors and Insulin-Producing Cells through BMP Signaling. Stem Cell Rev. 2011 Feb 5; Authors: Talavera-Adame D, Wu G, He Y, Ng TT, Gupta A, Kurtovic S, Hwang JY, Farkas DL, Dafoe DC Endothelial cells (ECs) represent the major component of the embryonic pancreatic niche and play a key role in the differentiation of insulin-producing β cells in vivo. However, it is unknown if ECs promote such differentiation in vitro. We investigated whether interaction of ECs with mouse embryoid bodies (EBs) in culture promotes differentiation of pancreatic progenitors and insulin-producing cells and the mechanisms involved. We developed a co-culture system of mouse EBs and human microvascular ECs (HMECs). An increase in the expression of the pancreatic markers PDX-1, Ngn3, Nkx6.1, proinsulin, GLUT-2, and Ptf1a was observed at the interface between EBs and ECs (EB-EC). No expression of these markers was found at the periphery of EBs cultured without ECs or those co-cultured with mouse embryonic fibroblasts (MEFs). At EB-EC interface, proinsulin and Nkx6.1 positive cells co-expressed phospho-Smad1/5/8 (pSmad1/5/8). Therefore, EBs were treated with HMEC conditioned media (HMEC-CM) suspecting soluble factors involved in bone morphogenetic protein (BMP) pathway activation. Upregulation of PDX-1, Ngn3, Nkx6.1, insulin-1, insulin-2, amylin, SUR1, GKS, and amylase as well as down-regulation of SST were detected in treated EBs. In addition, higher expression of BMP-2/-4 and their receptor (BMPR1A) were also found in these EBs. Recombinant human BMP-2 (rhBMP-2) mimicked the effects of the HMEC-CM on EBs. Noggin (NOG), a BMP antagonist, partially inhibited these effects. These results indicate that the differentiation of EBs to pancreatic progenitors and insulin-producing cells can be enhanced by ECs in vitro and that BMP pathway activation is central to this process. PMID: 21298405 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | L1CAM regulates DNA damage checkpoint response of glioblastoma stem cells through NBS1. EMBO J. 2011 Feb 4; Authors: Cheng L, Wu Q, Huang Z, Guryanova OA, Huang Q, Shou W, Rich JN, Bao S Glioblastomas (GBMs) are highly lethal brain tumours with current therapies limited to palliation due to therapeutic resistance. We previously demonstrated that GBM stem cells (GSCs) display a preferential activation of DNA damage checkpoint and are relatively resistant to radiation. However, the molecular mechanisms underlying the preferential checkpoint response in GSCs remain undefined. Here, we show that L1CAM (CD171) regulates DNA damage checkpoint responses and radiosensitivity of GSCs through nuclear translocation of L1CAM intracellular domain (L1-ICD). Targeting L1CAM by RNA interference attenuated DNA damage checkpoint activation and repair, and sensitized GSCs to radiation. L1CAM regulates expression of NBS1, a critical component of the MRE11-RAD50-NBS1 (MRN) complex that activates ataxia telangiectasia mutated (ATM) kinase and early checkpoint response. Ectopic expression of NBS1 in GSCs rescued the decreased checkpoint activation and radioresistance caused by L1CAM knockdown, demonstrating that L1CAM signals through NBS1 to regulate DNA damage checkpoint responses. Mechanistically, nuclear translocation of L1-ICD mediates NBS1 upregulation via c-Myc. These data demonstrate that L1CAM augments DNA damage checkpoint activation and radioresistance of GSCs through L1-ICD-mediated NBS1 upregulation and the enhanced MRN-ATM-Chk2 signalling. PMID: 21297581 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Tissue engineering of skin and soft tissue augmentation, medical view. J Med Assoc Thai. 2010 Dec;93 Suppl 7:S332-6 Authors: Hanpanich BS Tissue engineering is one application of the regenerative medicine, which aims to promote replace, repair or regeneration of tissue or organ due to congenital abnormalities, disease, trauma, or aging. This field applies the principles of physical sciences, engineering, medicine and the life sciences. To integrate knowledge of stem cell biology, tissue scaffold biocompatibility and degradation, bioreactor on cell growth and differentiation may overcome some limitation of autologous tissue grafting, allogenic tissue rejection. Tissue engineering is really a new hope for future medicine. PMID: 21294434 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Prolonged Sinus Pauses with Hydromorphone in the Absence of Cardiac Conduction Disease. South Med J. 2011 Feb 3; Authors: Snarr BS, Rowley CP, Phan SV, Achanti A, Hendrix GH A 49-year-old male had open sigmoid colectomy with colorectal anastomosis for sigmoid diverticulitis. The patient was given patient-controlled analgesia (PCA) hydromorphone and subsequently developed bradycardia with prolonged sinus pauses up to 7.1 seconds. The pauses resolved shortly after the hydromorphone was discontinued. This is the first case report to our knowledge of reversible prolonged sinus pauses associated with the use of hydromorphone. Animal studies support a role for opioid signaling at the sinoatrial (SA) node. Hydromorphone is a potential cause of prolonged sinus pauses and should be taken into consideration when monitoring a patient on hydromorphone for pain control. PMID: 21297541 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Tracheobronchial bio-engineering: Biotechnology fulfilling unmet medical needs. Adv Drug Deliv Rev. 2011 Feb 1; Authors: Walles T The development of substitutes for the human trachea or its bronchial tree represents a niche application in the rapidly advancing scientific field of Regenerative Medicine. Despite a comparatively small research foundation in the field of tracheo-bronchial bio-engineering, four different approaches have already been translated into clinical settings and applied in patients. This can be attributed to the lack of established treatment options for a small group of patients with extensive major airway disease. In this review, the clinical background and tissue specific basics of tracheo-bronchial bio-engineering will be evaluated. Focusing on the clinical applications of bio-engineered tracheal tissues, a "top-down" or "bedside-to-bench" analysis is performed in order to guide future basic and clinical research activities for airway-bioengineering. PMID: 21295094 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | HMGB1 release and redox regulation accompany regeneration and remodeling of skeletal muscle. Antioxid Redox Signal. 2011 Feb 5; Authors: Vezzoli M, Castellani P, Corna G, Castiglioni A, Bosurgi L, Monno A, Brunelli S, Manfredi AA, Rubartelli A, Rovere-Querini P HMGB1, a damage associated molecular pattern [DAMP] molecules, favors tissue regeneration via recruitment and activation of leukocytes and stem cells. Here we demonstrate, in a model of acute sterile muscle injury, that regeneration is accompanied by active ROS production counterbalanced and overcome by the generation of antioxidant moieties. Mitochondria are initially responsible for ROS formation. However they undergo rapid disruption with almost complete disappearance. Twenty-four hours following injury we observed a strong induction of MURF1 and Atrogin-1 ubiquitin ligases, key signals in activation of the proteasome system and induction of muscle atrophy. At later time points, ROS generation is maintained by non-mitochondrial sources. The antioxidant response occurs both in regenerating fibers and leukocytes that express high levels of free thiols and antioxidant enzymes, such as SOD-1 and thioredoxin. HMGB1, a protein thiol, weakly expressed in healthy muscles, increases during regeneration in parallel with the antioxidant response both in fibers and leukocytes. A reduced environment may be important to maintain HMGB1 bioactivity. Indeed, oxidation abrogates both muscle stem cell migration in response to HMGB1 and their ability to differentiate into myofibers in vitro. We propose that the early antioxidant response in regenerating muscle limits HMGB1 oxidation, thus allowing successful muscle regeneration. PMID: 21294652 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The effect of two and three dimensional cell culture on the chondrogenic potential of human adipose-derived mesenchymal stem cells after subcutaneous transplantation with an injectable hydrogel. Cell Transplant. 2011 Feb 3; Authors: Merceron C, Portron S, Masson M, Lesoeur J, Fellah BH, Gauthier O, Geffroy O, Weiss P, Guicheux J, Vinatier C Articular cartilage is an avascular tissue composed of chondrocytes, a unique cell type responsible for abundant matrix synthesis and maintenance. When damaged, it never heals spontaneously under physiological circumstances. Therefore, the delivery of mesenchymal stem cells using hydrogel has been considered for cartilage repair. This study aims at investigating the influence of in vitro chondrogenic differentiation of human adipose tissue-derived stem cells (hATSC) on in vivo cartilage formation when associated with a cellulose-based self-setting hydrogel (Si-HPMC). hATSC were characterized for their proliferation, surface marker expression and multipotency. The in vitro chondrogenic potential of hATSC cultured within Si-HPMC in control or chondrogenic medium was evaluated by measuring COL2A1 and ACAN expression by real time PCR. Alcian blue and type II collagen staining were also performed. To determine whether in vitro chondrogenically-differentiated hATSC may give rise to cartilage in vivo, cells differentiated as a monolayer or in pellets were finally associated with Si-HPMC and implanted subcutaneously into nude mice. Cartilage formation was assessed histologically by alcian blue and type II collagen staining. Our data demonstrate that hATSC exhibited proliferation and self-renewal. hATSC also expressed typical stem cell surface markers and were able to differentiate towards the adipo- osteo- and chondrogenic lineages. Real time-PCR and histological analysis indicated that Si-HPMC enabled chondrogenic differentiation of hATSC in inductive medium, as demonstrated by increased expression of chondrogenic markers. In addition, histological analysis of implants showed that chondrogenically-differentiated hATSC (monolayers or pellets), have the ability to form cartilaginous tissue, as indicated by the presence of sulphated-glycosaminoglycans and type II collagen. This study therefore suggests that an in vitro induction of hATSC in 2D was sufficient to obtain cartilaginous tissue formation in vivo. Si-HPMC associated with autologous hATSC could thus be a significant tool for regenerative medicine in the context of cartilage damage. PMID: 21294960 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The regenerative medicine laboratory: facilitating stem cell therapy for equine disease. Clin Lab Med. 2011 Mar;31(1):109-23 Authors: Borjesson DL, Peroni JF This article focuses on the emerging field of equine regenerative medicine with an emphasis on the use of mesenchymal stem cells (MSCs) for orthopedic diseases. We detail laboratory procedures and protocols for tissue handling and MSC isolation, characterization, expansion, and cryopreservation from bone marrow, fat, and placental tissues. We provide an overview of current clinical uses for equine MSCs and how MSCs function to heal tissues. Current laboratory practices in equine regenerative medicine mirror those in the human field. However, the translational use of autologous and allogeneic MSCs for patient therapy far exceeds what is currently permitted in human medicine. PMID: 21295725 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Regenerative medicine. Curr Probl Surg. 2011 Mar;48(3):148-212 Authors: Glotzbach JP, Wong VW, Gurtner GC, Longaker MT PMID: 21295632 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | The regenerative medicine laboratory: facilitating stem cell therapy for equine disease. Clin Lab Med. 2011 Mar;31(1):109-23 Authors: Borjesson DL, Peroni JF This article focuses on the emerging field of equine regenerative medicine with an emphasis on the use of mesenchymal stem cells (MSCs) for orthopedic diseases. We detail laboratory procedures and protocols for tissue handling and MSC isolation, characterization, expansion, and cryopreservation from bone marrow, fat, and placental tissues. We provide an overview of current clinical uses for equine MSCs and how MSCs function to heal tissues. Current laboratory practices in equine regenerative medicine mirror those in the human field. However, the translational use of autologous and allogeneic MSCs for patient therapy far exceeds what is currently permitted in human medicine. PMID: 21295725 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | The reversal of diabetes in rat model using mouse insulin producing cells - A combination approach of tissue engineering and macroencapsulation. Acta Biomater. 2011 Feb 1; Authors: Muthyala S, Raj VR, Mohanty M, Mohanan PV, Nair PD Type 1 diabetes is a chronic disorder that results due to auto immune destruction of insulin producing cells, a leading cause of morbidity and mortality all over the world. In this study, a tissue-engineering approach was compared with a macroencapsulation approach to reverse Type 1 diabetes in rat model, using mouse pancreatic progenitor (PPCs) derived islet-like clusters and mouse islets. For tissue engineering approach, the cells were cultured on GPE scaffolds (Gelatin scaffolds cross linked with EDC in presence of polyvinylpyrrolidone in vitro and for macroencapsulation approach, the cells were encapsulated in polyurethanes - polyvinylpyrrolidone semi interpenetrating network. In the combination approach, the cells cultured on GPE scaffolds were further encapsulated in PU-PVP capsule. The real-time PCR studies and glucose challenging assay have shown that the cells on GPE scaffolds could express and secrete insulin and glucagon in vitro. However, under in vivo conditions, the animals in tissue engineering approach died within 15- 20 days and failed to reverse diabetes, which was due to infiltration of immune cells such as CD4, CD8 and macrophages. In macroencapsulation approach, the animals could achieve euglycemia within 25 days and it was maintained for further 20 days, but after that the animals died. Interestingly, in combination approach, the animals could reverse hyperglycemia and maintained euglycemia up to 3 months. The time needed to achieve initial euglycemia was different with different cell types, i.e., The combination approach with mouse islets could achieve euglycemia within 15 days initially, where as with PPCs derived islet-like clusters could achieve euglycemia within 25 days only. This study confirmed that the combination of tissue engineering and macroencapsulation approach with mouse islets could reverse diabetes and maintain euglycemia in experimental diabetes rat model for 90 days. PMID: 21295162 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fibronectin distribution on demixed nanoscale topographies. Int J Artif Organs. 2011 Feb 4; Authors: Pérez-Garnes M, González-García C, Moratal D, Rico P, Salmerón-Sánchez M Purpose: It is known that surface nanotopography influences cell adhesion and differentiation. Our aim is to analyze the effect of nanoscale topography on fibronectin adsorption and, afterwards, on cell adhesion in order to rationalize the cell-material interaction by focusing on the state of the intermediate layer of adsorbed fibronectin at the material interphase. Methods: Nanotopographic surfaces were produced by demixing of thin film polymer blends - PLLA and PS - during a high speed spin-casting process. Fibronectin (FN) was adsorbed on the different nanotopographies and the protein distribution was directly observed by atomic force microscopy (AFM). The fraction of the surface covered by the protein was quantified by image analysis, as well as the distribution of FN between peaks and valleys. Focal adhesion protein -vinculin- was immunostained and quantified by image analysis on the different nanoscale surfaces. Results: Different nanoscale domains were obtained by changing the composition of the system within a height range of 3 nm to 30 nm. FN tends to adsorb on the peaks of nanoisland topographies, especially in compositions that did not enhance cell adhesion. Moreover, protein distribution between valleys and peaks alters the size of focal adhesion plaques, which grew larger on surfaces with an even distribution of fibronectin. Conclusions: Our results suggest that the surface nanotopography is a key material property capable of influencing protein adsorption. Additionally, the distribution of the protein on the different samples was correlated to the initial ability of cells to adhere in terms of the size of the focal plaques. PMID: 21298616 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Bioreactor System Using Noninvasive Imaging and Mechanical Stretch for Biomaterial Screening. Ann Biomed Eng. 2011 Feb 5; Authors: Kluge JA, Leisk GG, Cardwell RD, Fernandes AP, House M, Ward A, Dorfmann AL, Kaplan DL Screening of biomaterial and tissue systems in vitro, for guidance of performance in vivo, remains a major requirement in the field of tissue engineering. It is critical to understand how culture stimulation affects both tissue construct maturation and function, with the goal of eliminating resource-intensive trial-and-error screening and better matching specifications for various in vivo needs. In this article a multifunctional and robust bioreactor design that addresses this need is presented. The design enables a range of mechanical inputs, durations, and frequencies to be applied in coordination with noninvasive optical assessments. A variety of biomaterial systems, including micro- and nano-fiber and porous sponge biomaterials, as well as cell-laden tissue engineering constructs were used in validation studies to demonstrate the versatility and utility of this new bioreactor design. The silk-based biomaterials highlighted in these studies offered several unique optical signatures for use in label-free nondestructive imaging that allowed for sequential profiling. Both short- and long-term culture studies were conducted to evaluate several practical scenarios of usage: on a short-term basis, the authors demonstrate that construct cellularity can be monitored by usage of nonpermanent dyes; on a more long-term basis, the authors show that cell ingrowth can be monitored by green-fluorescent protein (GFP)-labeling, and construct integrity probed with concurrent load/displacement data. The ability to nondestructively track cells, biomaterials, and new matrix formation without harvesting designated samples at each time point will lead to less resource-intensive studies and should enhance our understanding and the discovery of biomaterial designs related to functional tissue engineering. PMID: 21298345 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Introducing RGD Peptides on PHBV Films through PEG-Containing Cross-Linkers to Improve the Biocompatibility. Biomacromolecules. 2011 Feb 4; Authors: Wang YY, Lü LX, Shi JC, Wang HF, Xiao ZD, Huang NP Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a biodegradable polyester, has been a good candidate of biomaterial employed in tissue engineering. However, the PHBV film is hydrophobic and has no recognition sites for cell attachment. In this study, PHBV films are activated by ammonia plasma treatment to produce amino groups on the surface, followed by sequential reactions with a heterobifunctional cross-linker containing a segment of poly(ethylene glycol) (PEG) and further with RGD-containing peptides. XPS analyses of modified surfaces after each reaction step reveal that the RGD-containing peptides have been covalently grafted onto PHBV films. The result of cell viability assay indicates that the RGD-modified PHBV films exhibit a distinctly improved cellular compatibility. Moreover, according to the results of serum adsorption tests by optical waveguide lightmode spectroscopy (OWLS) and fibrinogen adsorption tests by enzyme-linked immunosorbent assay (ELISA) on unmodified and modified PHBV surfaces, the introduced PEG chains can significantly decrease the nonspecific adsorption of proteins from serum and fibrinogen from plasma, thus decreasing the risk of thrombus formation and improving the blood compatibility of implanted materials. PMID: 21294539 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Regenerated Silk Fibroin Nanofibrous Matrices Treated with 75% Ethanol Vapor for Tissue-Engineering Applications. J Biomater Sci Polym Ed. 2011 Jan 28; Authors: Fan L, Wang H, Zhang K, He C, Cai Z, Mo X As an excellent biocompatible and biodegradable protein polymer, silk fibroin (SF) has found wide applications, particularly serving as therapeutic agent for tissue-engineering applications, on which both post-spin treatment and sterilization processing are crucial to drug-loaded matrices. To find a safe, effective and appropriate post-spin treatment and sterilization approach for drug-loaded biomaterial matrices is one of the major problems in the field of tissue engineering at present. In this work, a simple, safe and effective approach skillfully integrating post-spin treatment with sterilization processing was developed to drug-loaded SF nanofibrous matrices. Electrospun SF nanofibrous matrices from its aqueous solution were post-treated with 75% ethanol vapor. (13)C-NMR and WAXD analysis demonstrated that such post-spin treatment rendered the structure of SF nanofibrous matrices transform from the silk I form to the silk II form. Furthermore, biological assays suggested that as-treated SF nanofibrous matrices significantly promoted the development of murine connective tissue fibroblasts. Skillfully integrated with novel sterilization processing, 75% ethanol vapor treatment could be a potential approach to designing and fabricating diverse drug-loaded SF nanofibrous matrices serving as therapeutic agents for tissue-engineering applications in that it can effectively protect the drug from losing compared with traditional post-spin treatment and sterilization processing. PMID: 21294970 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Hierarchical nanoengineered surfaces for enhanced cytoadhesion and drug delivery. Biomaterials. 2011 Feb 4; Authors: Fischer KE, Nagaraj G, Hugh Daniels R, Li E, Cowles VE, Miller JL, Bunger MD, Desai TA Delivering therapeutics to mucosal tissues such as the nasal and gastrointestinal tracts is highly desirable due to ease of access and dense vasculature. However, the mucus layer effectively captures and removes most therapeutic macromolecules and devices. In previous work, we have shown that nanoengineered microparticles (NEMPs) adhere through the mucus layer, exhibiting up to 1000 times the pull-off force of an unmodified microsphere, and showing greater adhesion than some chemical targeting means. In this paper, we demonstrate that nanotopography improves device adhesion in vivo, increasing retention time up to ten-fold over unmodified devices. Moreover, we observe considerable adhesion in several cell lines using an in vitro shear flow model, indicating that this approach is promising for numerous tissues. We then demonstrate that nanowire-mediated adhesion is highly robust to variation in nanowire surface charge and cellular structure and function, and we characterize particle loading and elution. We present a form of cytoadhesion that utilizes the physical interaction of nanoengineered surfaces with subcellular structures to produce a robust and versatile cytoadhesive for drug delivery. These nanoscale adhesive mechanisms are also relevant to fields such as tissue engineering and wound healing because they likely affect stem cell differentiation, cell remodeling, migration, etc. PMID: 21296409 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Synthesis and characterization of photocrosslinkable gelatin and silk fibroin interpenetrating polymer network hydrogels. Acta Biomater. 2011 Feb 1; Authors: Xiao W, He J, Nichol JW, Wang L, Hutson CB, Wang B, Du Y, Fan H, Khademhosseini A To effectively repair or replace damaged tissues, it is necessary to design scaffolds with tunable structural and biomechanical properties that closely mimic the host tissue. In this paper, we describe a newly synthesized photocrosslinkable interpenetrating polymer network (IPN) hydrogel based on gelatin methacrylate (GelMA) and silk fibroin (SF) formed by sequential polymerization, which possesses tunable structural and biological properties. Experimental results revealed that IPNs, where both the GelMA and SF were independently crosslinked in interpenetrating networks, demonstrated a lower swelling ratio, higher compressive modulus and lower degradation rate as compared to the GelMA and semi-IPN hydrogels, where only GelMA was crosslinked. These differences were likely caused by a higher degree of overall crosslinking due to the presence of crystallized SF in the IPN hydrogels. NIH-3T3 fibroblasts readily attached to, spread, and proliferated on the surface of IPN hydrogels as demonstrated by F-actin staining and analysis of mitochondrial activity (MTT). In addition, photolithography combined with lyophilization techniques was used to fabricate 3D micropatterned and porous micro-scaffolds from GelMA-SF IPN hydrogels, furthering their versatility for use in various microscale tissue engineering applications. Overall, this study introduces a class of photocrosslinkable, mechanically robust and tunable IPN hydrogels that could be useful for various tissue engineering and regenerative medicine applications. PMID: 21295165 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Tissue engineering of skin and soft tissue augmentation, medical view. J Med Assoc Thai. 2010 Dec;93 Suppl 7:S332-6 Authors: Hanpanich BS Tissue engineering is one application of the regenerative medicine, which aims to promote replace, repair or regeneration of tissue or organ due to congenital abnormalities, disease, trauma, or aging. This field applies the principles of physical sciences, engineering, medicine and the life sciences. To integrate knowledge of stem cell biology, tissue scaffold biocompatibility and degradation, bioreactor on cell growth and differentiation may overcome some limitation of autologous tissue grafting, allogenic tissue rejection. Tissue engineering is really a new hope for future medicine. PMID: 21294434 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Caprine (Goat) Collagen: A Potential Biomaterial for Skin Tissue Engineering. J Biomater Sci Polym Ed. 2011 Jan 28; Authors: Banerjee I, Mishra D, Das T, Maiti S, Maiti TK Collagens presently used in tissue engineering are primarily of bovine or porcine origin. However, a risk of a spongiform encephalopathy epidemic has limited the use of collagen from these sources. Keeping the aforementioned perspective in mind, we explored the possibility of using domestic goat available in the subcontinent as a potential source of collagen for tissue-engineering application. This article delineates the isolation, physico-chemical characterization, biocompatibility study and wound healing application of acid soluble caprine (goat) tendon collagen (GTC). Physico-chemical characterization of 1% acetic acid extracted GTC was done by SDS-PAGE, amino-acid composition analysis, FT-IR and CD spectroscopy. Results revealed that GTC was comprised of type-I collagen. Biocompatibility study showed that GTC augmented cell adhesion, cell cycle progression and proliferation. Immuno-cytochemical analysis in conjugation with traction force microscopy further confirmed a superior focal adhesion complex mediated cell-substrate interaction in GTC. Finally, in vivo study in mice model revealed that GTC has low immunogenicity and it augments healing process significantly. Throughout the study, calf skin collagen (CSC) was used as standard for comparative evaluation. In conclusion, it can be said that GTC may find its application as biomaterial in skin tissue engineering. PMID: 21294966 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Meniscal tears, repairs and replacement: their relevance to osteoarthritis of the knee. Br J Sports Med. 2011 Feb 5; Authors: McDermott I The menisci of the knee are important load sharers and shock absorbers in the joint. Meniscal tears are common, and whenever possible meniscal tears should be surgically repaired. Meniscectomy leads to a significant increased risk of osteoarthritis, and various options now exist for replacing missing menisci, including the use of meniscal scaffolds or the replacement of the entire meniscus by meniscal allograft transplantation. The field of meniscal surgery continues to develop apace, and the future may lie in growing new menisci by tissue engineering techniques. PMID: 21297172 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Antibiotic-Releasing Porous Polymethylmethacrylate/Gelatin/Antibiotic Constructs for Craniofacial Tissue Engineering. J Control Release. 2011 Feb 1; Authors: Shi M, Kretlow JD, Spicer PP, Tabata Y, Demian N, Wong ME, Kasper FK, Mikos AG An antibiotic-releasing porous polymethylmethacrylate (PMMA) construct was developed to maintain the bony space and prime the wound site in the initial step of a two-stage regenerative medicine approach toward reconstructing significant bony or composite craniofacial tissue defects. Porous polymethylmethacrylate (PMMA) constructs incorporating gelatin microparticles (GMPs) were fabricated by the sequential assembly of GMPs, the antibiotic colistin, and a clinically used bone cement formulation of PMMA powder and methylmethacrylate liquid. PMMA/gelatin/antibiotic constructs with varying gelatin incorporation and drug content were investigated to elucidate the relationship between material composition and construct properties (porosity and drug release kinetics). The porosity of PMMA/gelatin/antibiotic constructs ranged between 7.6±1.8-38.4±1.4% depending on the amount of gelatin incorporated and the drug solution added for gelatin swelling. The constructs released colistin over 10 or 14 days with an average release rate per day above 10 μg/ml. The porosity and in vitro colistin release kinetics of PMMA/gelatin/antibiotic constructs were tuned by varying the material composition and fabrication parameters. This study demonstrates the potential of gelatin-incorporating PMMA constructs as a functional space maintainer for both promoting tissue healing/coverage and addressing local infections, enabling better long-term success of the definitive regenerated tissue construct. PMID: 21295086 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Synthesis of Temperature-Responsive Dextran-MA/PNIPAAm Particles for Controlled Drug Delivery Using Superhydrophobic Surfaces. Pharm Res. 2011 Feb 5; Authors: Lima AC, Song W, Blanco-Fernandez B, Alvarez-Lorenzo C, Mano JF PURPOSE: To implement a bioinspired methodology using superhydrophobic surfaces suitable for producing smart hydrogel beads in which the bioactive substance is introduced in the particles during their formation. METHODS: Several superhydrophobic surfaces, including polystyrene, aluminum and copper, were prepared. Polymeric solutions composed by photo-crosslinked dextran-methacrylated and thermal responsive poly(N-isopropylacrylamide) mixed with a protein (insulin or albumin) were dropped on the superhydrophobic surfaces, and the obtained millimetric spheres were hardened in a dry environment under UV light. RESULTS: Spherical and non-sticky hydrogels particles were formed in few minutes on the superhydrophobic surfaces. The proteins included in the liquid formulation were homogeneously distributed in the particle network. The particles exhibited temperature-sensitive swelling, porosity and protein release rate, with the responsiveness tunable by the dextran-MA/PNIPAAm weight ratio. CONCLUSIONS: The proposed method permitted the preparation of smart hydrogel particles in one step with almost 100% encapsulation yield. The temperature-sensitive release profiles suggest that the obtained spherical-shaped biomaterials are suitable as protein carriers. These stimuli-responsive beads could have potential to be used in pharmaceutical or other biomedical applications, including tissue engineering and regenerative medicine. PMID: 21298327 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | Knoepfler Lab Graphic
It's pretty easy to tell where the sweet stuff is going when it comes to the California stem cell agency.
Take a quick look at CIRM's list of grants and their recipients. Stanford, UCLA and UC San Francisco top the list with $437 million out of the $1.2 billion the agency has handed out so far.
The agency has not blessed its fans yet with a list of individual scientists | | | | | | | | | |  | |  | |  |
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