|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Novel genetic loci associated with prostate cancer in the Japanese population. Asian J Androl. 2010 Oct 11; Authors: Sun Y, Huang J PMID: 20935669 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Vascular smooth muscle enhances functionality of tissue-engineered blood vessels in vivo. J Vasc Surg. 2010 Oct 8; Authors: Neff LP, Tillman BW, Yazdani SK, Machingal MA, Yoo JJ, Soker S, Bernish BW, Geary RL, Christ GJ OBJECTIVES:: There is significant room for improvement in the development of tissue-engineered blood vessels (TEBVs) for vascular reconstruction. Most commonly, TEBVs are seeded with endothelial cells (ECs) only. This provides an antithrombogenic surface but suboptimal physiologic characteristics compared with native arteries, due to lack of smooth muscle cells (SMCs) in the vessel media. Although SMCs are critical in vessel architecture and function throughout the vascular tree, few studies have incorporated SMCs in TEBVs implanted in vivo. As such, the goal of the present study was to evaluate the effect of SMC coseeding with ECs on TEBV maturation, structure, and function after prolonged in vivo maturation. METHODS:: Dual-seeded TEBVs (dsTEBVs) were created by coseeding autologous ECs derived from circulating progenitor cells and SMCs from artery explants onto the lumen and outer surface of extracellular matrix scaffolds, respectively. Control vessels were seeded with ECs alone (ecTEBV). All vessels were preconditioned to pulsatile flow for 10 to 14 days in a bioreactor, implanted as arterial interposition grafts in sheep, and allowed to heal and adapt in vivo for 4 months before ex vivo physiologic testing and histologic analysis. RESULTS:: All implants were patent at 4 months. There were no structural failures, aneurysms, or infectious complications. The dsTEBVs exhibited a greater degree of wall maturation, characterized by higher medial cellularity (P = .01) and greater percentage of α-actin (P = .005) and SMC-specific muscle myosin heavy chain (P = .005) staining compared with ecTEBVs. Contractile responses to phenylephrine and serotonin were significantly greater in isolated rings of dsTEBVs than those observed in ecTEBVs (P = .01). CONCLUSIONS:: To our knowledge, this is the first study that demonstrates enhanced in vivo wall maturation and contractile function of TEBVs coseeded with autologous SMCs and ECs compared with EC seeding alone. These data suggest a coseeding strategy can be accomplished in a clinically relevant timeframe (typically 6 weeks) and may provide advantages for arterial reconstruction compared with vessels engineered only with endothelium. PMID: 20934837 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Bridge to ReBIO: Partnering universities and high schools for science outreach. Dev Biol. 2010 Aug 1;344(1):437 Authors: Skirkanich J, Shuda JR, Anzaldo J, Kessler D PMID: 20933720 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Bridge to ReBIO: Partnering universities and high schools for science outreach. Dev Biol. 2010 Aug 1;344(1):421 Authors: Skirkanich J, Shuda JR, Anzaldo J, Kessler D PMID: 20933677 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Green processing of chitin porous structures for biomedical applications combining ionic liquids and supercritical fluid technology. Acta Biomater. 2010 Oct 6; Authors: S Silva S, Duarte AR, Carvalho AP, Mano JF, Reis RL The application of green chemistry principles in the processing of materials for advanced technologies is a continuous increasing research field. In this work chitin-porous materials were developed combining the processing of chitin using ionic liquids (IL), as green solvent together with the use of supercritical fluid technology (SCF) as clean technology. Chitin was dissolved in 1-butyl-3-imidazolium acetate, followed by regeneration of polymer in ethanol in specific moulds. The IL removal was performed using soxhlet extraction and successive steps of extraction with SCF using carbon dioxide/ethanol ratios of 50/50 and 70/30. The developed chitin-based porous structures (ChIL) can be classified as mesoporous materials, with very low density and high porosity. The cytotoxicity of ChIL extracts using L929 fibroblast-like cells was investigated, and the results demonstrated that the produced materials have extremely low cytotoxicity levels. Therefore, the findings suggest that the chitin porous structures may be potential candidates for relevant biomedical applications, including tissue engineering. PMID: 20933617 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The spreading, migration and proliferation of mouse mesenchymal stem cells cultured inside hyaluronic acid hydrogels. Biomaterials. 2010 Oct 7; Authors: Lei Y, Gojgini S, Lam J, Segura T Synthetic hydrogel scaffolds that can be used as culture systems that mimic the natural stem cell niche are of increased importance for stem cell biology and regenerative medicine. These artificial niches can be utilized to control the stem cell fate and will have potential applications for expanding/differentiating stem cells in vitro, delivering stem cells in vivo, as well as making tissue constructs. In this study, we synthesized hyaluronic acid (HA) hydrogels that could be degraded through a combination of cell-released enzymes and used them to culture mouse mesenchymal stem cells (mMSC). To form the hydrogels, HA was modified to contain acrylate groups and crosslinked through Michael addition chemistry using non-degradable, plasmin degradable or matrix metalloproteinase (MMP) degradable crosslinkers. Using this hydrogel we found that mMSC proliferation occurred in the absence of cell spreading, that mMSCs could only spread when both RGD and MMP degradation sites were present in the hydrogel and that mMSCs in hydrogels with high density of RGD (1000 μm) spread and migrated faster and more extensively than in hydrogels with low density of RGD (100 μm). PMID: 20933268 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | New players enter field of regenerative medicine. Manag Care. 2010 Sep;19(9):48-9 Authors: Morrow T PMID: 20931895 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Ecto-mesenchymal stem cells from dental pulp are committed to differentiate into active melanocytes. Eur Cell Mater. 2010;20:295-305 Authors: Paino F, Ricci G, De Rosa A, D'Aquino R, Laino L, Pirozzi G, Tirino V, Papaccio G Dental pulp stem cells (DPSCs) are multipotent stem cells derived from neural crest and mesenchyme and have the capacity to differentiate into multiple cell lineages. It has already been demonstrated that DPSCs differentiate into melanocyte-like cells but only when cultivated in a specific melanocyte differentiating medium. In this study we have shown, for the first time, that DPSCs are capable of spontaneously differentiating into mature melanocytes, which display molecular and ultrastructural features of full development, including the expression of melanocyte specific markers and the presence of melanosomes up to the terminal stage of maturation. We have also compared the differentiating features of DPSCs grown in different culture conditions, following the timing of differentiation at molecular and cytochemical levels and found that in all culture conditions full development of these cells was obtained, although at different times. The spontaneous differentiating potential of these cells strongly suggests their possible applications in regenerative medicine. PMID: 20931491 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Regulatory enablers and regulatory challenges for the development of tissue-engineered products in the EU. Biomed Mater Eng. 2010 Jan 1;20(3):121-6 Authors: Brévignon-Dodin L The EU Regulation on Advanced Therapy Medicinal Products (ATMP) bridges a regulatory gap and is expected to act as an enabler for the regenerative medicine sector in the EU by setting a centralised and harmonised regulatory framework for tissue-engineered products. Some of its key features are a workable and comprehensive scope, a new committee allowing for a pooling of expertise and tailored yet flexible requirements meant to keep pace with technology development. However, while providing a much needed regulatory framework, the new regulation still has potential shortfalls with regard to facilitating the research and commercialisation of tissue-engineered products in the future. PMID: 20930319 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Stem Cell-Calcium Phosphate Constructs for Bone Engineering. J Dent Res. 2010 Oct 6; Authors: Xu HH, Zhao L, Weir MD While human bone-marrow-derived mesenchymal stem cells (hBMSCs) have been investigated, human umbilical cord mesenchymal stem cells (hUCMSCs) are a relatively new cell source. Little has been reported on hUCMSC encapsulation in scaffolds for bone tissue engineering. The objective of this study was to encapsulate hBMSCs and hUCMSCs in calcium phosphate cement (CPC) scaffolds for dental, craniofacial, and orthopedic applications. Stem-cell-encapsulating CPC construct with chitosan and fiber reinforcement reached the strength of cancellous bone, which was much stronger than previous injectable carriers for cell delivery. hUCMSCs and hBMSCs inside the constructs showed excellent viability and osteo-differentiation. The encapsulated hUCMSCs synthesized nearly three-fold more bone minerals than the hBMSCs in vitro. Hence, stem-cell-encapsulating CPC-chitosan-fiber construct may be promising for dental and orthopedic applications. This study indicated that the hUCMSCs were a potent alternative to the gold-standard hBMSCs, which may have a broad impact on regenerative medicine and dental tissue engineering. PMID: 20929721 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Autologous chondrocyte implantation for full thickness articular cartilage defects of the knee. Cochrane Database Syst Rev. 2010;10:CD003323 Authors: Vasiliadis HS, Wasiak J BACKGROUND: Treatments for managing articular cartilage defects of the knee, including drilling and abrasion arthroplasty, are not always effective. When they are, long-term benefits may not be maintained and osteoarthritis may develop. An alternative is autologous chondrocyte implantation (ACI), the surgical implantation of healthy cartilage cells into the damaged areas. OBJECTIVES: To determine the efficacy and safety of ACI in people with full thickness articular cartilage defects of the knee. SEARCH STRATEGY: We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (3 December 2008), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2008, Issue 4), MEDLINE (1950 to November Week 3 2008), EMBASE (1980 to Week 48 2008), SPORTDiscus (3 December 2008), the WHO International Clinical Trials Registry Platform (4 December 2008), and Current Controlled Trials (3 December 2008). SELECTION CRITERIA: Randomised and quasi-randomised trials comparing ACI with any other type of treatment (including no treatment or placebo) for symptomatic cartilage defects of the medial or lateral femoral condyle, femoral trochlea or patella. DATA COLLECTION AND ANALYSIS: Review authors selected studies for inclusion independently. We assessed risk of bias based on adequacy of the randomisation and allocation concealment process, potential for selection bias after allocation and level of masking. We did not pool data due to clinical and methodological heterogeneity. MAIN RESULTS: Six heterogeneous trials were identified with 431 participants. Methodological flaws of the included trials included incomplete follow-up and inadequate reporting of outcomes. Three trials compared ACI versus mosaicplasty. One reported statistically significant results in favour of ACI at one year in the numbers of people with 'good' or 'excellent' functional results. Conversely, another trial found significant improvement for the mosaicplasty group when assessed using one functional scoring system at two years, but no statistically significant differences based on two other scoring systems. A third trial found no difference between ACI and mosaicplasty, 10 months on average after the surgery.There was no statistically significant difference in functional outcomes at two years in single trials comparing ACI with microfracture or characterised chondrocyte implantation versus microfracture. The results of the sixth trial comparing matrix-guided ACI versus microfracture were undermined by the severe loss to follow-up. AUTHORS' CONCLUSIONS: There is insufficient evidence to draw conclusions on the use of ACI for treating full thickness articular cartilage defects in the knee. Further good quality randomised controlled trials with long-term functional outcomes are required. PMID: 20927732 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Quantification of three-dimensional cell-mediated collagen remodeling using graph theory. PLoS One. 2010;5(9): Authors: Bilgin CC, Lund AW, Can A, Plopper GE, Yener B BACKGROUND: Cell cooperation is a critical event during tissue development. We present the first precise metrics to quantify the interaction between mesenchymal stem cells (MSCs) and extra cellular matrix (ECM). In particular, we describe cooperative collagen alignment process with respect to the spatio-temporal organization and function of mesenchymal stem cells in three dimensions. METHODOLOGY/PRINCIPAL FINDINGS: WE DEFINED TWO PRECISE METRICS: Collagen Alignment Index and Cell Dissatisfaction Level, for quantitatively tracking type I collagen and fibrillogenesis remodeling by mesenchymal stem cells over time. Computation of these metrics was based on graph theory and vector calculus. The cells and their three dimensional type I collagen microenvironment were modeled by three dimensional cell-graphs and collagen fiber organization was calculated from gradient vectors. With the enhancement of mesenchymal stem cell differentiation, acceleration through different phases was quantitatively demonstrated. The phases were clustered in a statistically significant manner based on collagen organization, with late phases of remodeling by untreated cells clustering strongly with early phases of remodeling by differentiating cells. The experiments were repeated three times to conclude that the metrics could successfully identify critical phases of collagen remodeling that were dependent upon cooperativity within the cell population. CONCLUSIONS/SIGNIFICANCE: Definition of early metrics that are able to predict long-term functionality by linking engineered tissue structure to function is an important step toward optimizing biomaterials for the purposes of regenerative medicine. PMID: 20927339 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Endogenous c-jun Inhibits Mammary Epithelial Cellular Apoptosis In Vivo. Mol Biol Cell. 2010 Oct 6; Authors: Katiyar S, Casimiro MC, Dettin L, Ju X, Wagner EW, Tanaka H, Pestell RG Monitoring Editor: Kunxin Luo c-jun, which is overexpressed in a number of human cancers encodes a critical component of the AP-1 complex. c-jun has been shown to either induce or inhibit cellular apoptosis. Germ line deletion of both c-jun alleles is embryonically lethal. To determine the role of the endogenous c-jun gene in apoptosis, we performed mammary epithelial cell targeted somatic deletion using floxed c-jun (c-jun(f/f)) conditional knockout mice. Laser capture microdissection demonstrated endogenous c-jun inhibits expression of apoptosis inducing genes and ROS reducing genes (MnSOD, Catalase). Reactive oxygen species (ROS) have been implicated in apoptosis and undergo enzymatic elimination via MnSOD and CuZnSOD with further detoxification via catalase. c-jun mediated survival was in part dependent upon ROS production. c-jun mediated repression of MnSOD and catalase occurred via mitochondrial complex I and NOX I. Collectively, these studies define a pivotal role of endogenous c-jun in promoting cell survival via maintaining mitochondrial integrity and expression of the key regulators of ROS production. PMID: 20926681 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Histone H1 Poly[ADP]-Ribosylation Regulates the Chromatin Alterations Required for Learning Consolidation. J Neurosci. 2010 Oct 6;30(40):13305-13 Authors: Fontán-Lozano A, Suárez-Pereira I, Horrillo A, Del-Pozo-Martín Y, Hmadcha A, Carrión AM Memory formation requires changes in gene expression, which are regulated by the activation of transcription factors and by changes in epigenetic factors. Poly[ADP]-ribosylation of nuclear proteins has been postulated as a chromatin modification involved in memory consolidation, although the mechanisms involved are not well characterized. Here we demonstrate that poly[ADP]-ribose polymerase 1 (PARP-1) activity and the poly[ADP]-ribosylation of proteins over a specific time course is required for the changes in synaptic plasticity related to memory stabilization in mice. At the molecular level, histone H1 poly[ADP]-ribosylation was evident in the hippocampus after the acquisition period, and it was selectively released in a PARP-1-dependent manner at the promoters of cAMP response element-binding protein and nuclear factor-κB dependent genes associated with learning and memory. These findings suggest that histone H1 poly[ADP]-ribosylation, and its loss at specific loci, is an epigenetic mechanism involved in the reprogramming of neuronal gene expression required for memory consolidation. PMID: 20926656 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | To {beta}-e or Not to {beta}-e Replicating after 30: Retrospective Dating of Human Pancreatic Islets. J Clin Endocrinol Metab. 2010 Oct;95(10):4552-4 Authors: Cobo-Vuilleumier N, Gauthier BR PMID: 20926542 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Translation and commercialization of regenerative medicines. J R Soc Interface. 2010 Oct 6; Authors: Polak J, Bravery CA, Prescott C PMID: 20926428 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A probabilistic cell model in background corrected image sequences for single cell analysis. Biomed Eng Online. 2010 Oct 6;9(1):57 Authors: N Kachouie N, Fieguth P, Jervis E ABSTRACT: BACKGROUND: Methods of manual cell localization and outlining are so onerous that automated tracking methods would seem mandatory for handling huge image sequences, nevertheless manual tracking is, astonishingly, still widely practiced in areas such as cell biology which are outside the influence of most image processing research. The goal of our research is to address this gap by developing automated methods of cell tracking, localization, and segmentation. Since even an optimal frame-to-frame association method cannot compensate and recover from poor detection, it is clear that the quality of cell tracking depends on the quality of cell detection within each frame. METHODS: Cell detection performs poorly where the background is not uniform and includes temporal illumination variations, spatial non-uniformities, and stationary objects such as well boundaries (which confine the cells under study). To improve cell detection, the signal to noise ratio of the input image can be increased via accurate background estimation. In this paper we investigate background estimation, for the purpose of cell detection. We propose a cell model and a method for background estimation, driven by the proposed cell model, such that well structure can be identified, and explicitly rejected, when estimating the background. RESULTS: The resulting background-removed images have fewer artifacts and allow cells to be localized and detected more reliably. The experimental results generated by applying the proposed method to different Hematopoietic Stem Cell (HSC) image sequences are quite promising. CONCLUSION: The understanding of cell behavior relies on precise information about the temporal dynamics and spatial distribution of cells. Such information may play a key role in disease research and regenerative medicine, so automated methods for observation and measurement of cells from microscopic images are in high demand. The proposed method in this paper is capable of localizing single cells in microwells and can be adapted for the other cell types that may not have circular shape. This method can be potentially used for single cell analysis to study the temporal dynamics of cells. PMID: 20925919 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | FDA challenges stem-cell clinic. Nature. 2010 Aug 19;466(7309):909 Authors: Cyranoski D PMID: 20725009 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | [Peptide science for cell adhesive molecules] Seikagaku. 2010 Jun;82(6):463-73 Authors: Katagiri F, Nomizu M PMID: 20662254 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Characterization of a diverse secretome generated by the mouse preimplantation embryo in vitro. Reprod Biol Endocrinol. 2010;8:71 Authors: Beardsley AJ, Li Y, O'Neill C This study investigates the suitability of surface-enhanced laser desorption and ionization time-of-flight (SELDI-TOF) and electrospray ionization (ESI) mass spectrometry for analysis of the proteins released by the mouse preimplantation embryo in vitro. SELDI-TOF analysis with CM10 or IMAC30 (but not Q10) protein chips detected a protein peak at m/z approximately 8570 released by both C57BL6 and hybrid embryos. No other peaks unique to the presence of the embryo were identified with this method. ESI mass spectrometry of tryptic digests of embryo-conditioned media identified a total of 20 proteins released during development from the zygote to blastocyst stage. Four proteins were expressed in at least 7 out of 8 cultures tested, one of these (lactate dehydrogenase B) was in all cultures. A further five proteins were in at least half of the cultures and 11 more proteins were in at least one culture. The expression of two of these proteins is essential for preimplantation embryo development (NLR family, pyrin domain containing 5 and peptidyl arginine deiminase, type VI). A further four proteins detected have roles in redox regulation of cells, and three others are capable of inducing post-translational modifications of proteins. This study shows the feasibility of ESI mass spectrometry for identifying the proteins secreted by the preimplantation embryo in vitro. This analysis identifies a range of targets that now require detailed functional analysis to assess whether their release by the embryo is an important property of early embryo development. PMID: 20569467 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cell homing in musculoskeletal injury. Biomaterials. 2010 Oct 6; Authors: Fong EL, Chan CK, Goodman SB The regenerative potential of injured adult tissue suggests the physiological existence of cells capable of participating in the reparative process. Recent studies indicate that stem-like cells residing in tissues contribute to tissue repair and are replenished by precursor bone marrow-derived cells. Mesenchymal stromal cells (MSC) are among the candidates for reparative cells. These cells can potentially be mobilized into the circulation in response to injury signals and exert their reparative effects at the site of injury. Current therapies for musculoskeletal injuries pose unavoidable risks which can impede full recovery. Trafficking of MSC to the injury site and their subsequent participation in the regenerative process is thought to be a natural healing response that can be imitated or augmented by enhancing the endogenous MSC pool with exogenously administered MSC. Therefore, a promising alternative to the existing strategies employed in the treatment of musculoskeletal injuries is to reinforce the inherent reparative capacity of the body by delivering MSC harvested from the patient's own tissues to the site of injury. The aim of this review is to inform the reader of studies that have evaluated the intrinsic homing and regenerative abilities of MSC, with particular emphasis on the repair of musculoskeletal injuries. Research that supports the direct use of MSC (without in vitro differentiation into tissue-specific cells) will also be reported. Based on accruing evidence that the natural healing mechanism involves the recruitment of MSC and their subsequent reparative actions at the site of injury, as well as documented therapeutic response after the exogenous administration of MSC, the feasibility of the emerging strategy of instant stem-cell therapy will be proposed. PMID: 20933277 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Concerns and Hopes for Stem Cell Therapy in Cardiology: Focus on Endothelial Progenitor Cells. Cardiovasc Hematol Disord Drug Targets. 2010 Jul 19; Authors: Ferrari R, Beltrami CA, Tavazzi L The crucial role played by the endothelium in cardiovascular disorders has been repetitively recognised. Endothelium injury has been implicated in atherosclerosis, thrombosis, hypertension and other cardiovascular diseases. Recently, however, research has undertaken a new avenue. As mature endothelial cells posses limited regenerative capacities, the interest has been switched to the circulating endothelial progenitor cells (EPCs). Indeed, the scientific community has made progress in understanding the role of EPCs in the maintenance of endothelial integrity and function as well as post natal neovascularisation. It has been suggested that these cells are able to home in the site of heart injury / damage and that they might take part in angiogenesis, giving hope for new treatment opportunities. There is evidence that reduced availability of EPCs or impairment of their function is associated with more severe CV disease and to comorbid risk factors. Different current drug regimes are able to influence bone marrow production and release of EPCs and several growth factors are considered for possible useful new therapeutic approaches. Thus, many studies into the potential use of EPCs in the clinical setting have recently been conducted with conflicting results. The goal of this review article is to discuss current therapies to regenerate new vessels and therefore to enhance myocardial function. The article overviews the search strategy and the pathophysiological aspects behind this therapy, consider the target currently under investigation and set the stage for new ideas. PMID: 20929437 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Cartilage tissue engineering: From hydrogel to mesenchymal stem cells. Biomed Mater Eng. 2010 Jan 1;20(3):159-66 Authors: Merceron C, Portron S, Masson M, Fellah BH, Gauthier O, Lesoeur J, Chérel Y, Weiss P, Guicheux J, Vinatier C Articular cartilage does not repair itself spontaneously. To promote its repair, the transfer of stem cells from adipose tissue (ATSC) using an injectable self-setting cellulosic-hydrogel (Si-HPMC) appears promising. In this context, the objective of this work was to investigate the influence of in vitro chondrogenic differentiation of ATSC on the in vivo cartilage formation when combined with Si-HPMC. In a first set of experiments, we characterized ATSC for their ability to proliferate, self renew and express typical mesenchymal stem cell surface markers. Then, the potential of ATSC to differentiate towards the chondrogenic lineage and the optimal culture conditions to drive this differentiation were evaluated. Real-time RT-PCR and histological analysis for sulphated glycosaminoglycans and type II collagen revealed that 3-dimensional culture and hypoxic condition favored ATSC chondrogenesis regarding mRNA expression level and the corresponding proteins production. In order to assess the phenotypic stability of chondrogenically-differentiated ATSC, real-time RT-PCR for specific terminal chondrogenic markers and alkaline phosphatase activity assay were performed. In addition to promote chondrogenesis, our culture conditions seem to prevent the terminal differentiation of ATSC. Histological examination of ATSC/Si-HPMC implants suggested that the in vitro chondrogenic pre-commitment of ATSC in monolayer is sufficient to obtain cartilaginous tissue in vivo. PMID: 20930323 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Differentiated human adipose-derived stem cells exhibit hepatogenic capability in vitro and in vivo. J Cell Physiol. 2010 Nov;225(2):429-36 Authors: Ruiz JC, Ludlow JW, Sherwood S, Yu G, Wu X, Gimble JM The availability of suitable human livers for transplantation falls short of the number of potential patients. In addition, the availability of primary human hepatocytes for cell-therapy and drug development applications is significantly limited; less than 700 livers per year are available for such studies. However, the majority of these organs cannot be utilized due to pathological infections (e.g., HepB, HepC, or HIV) or excessive levels of steatosis. Thus, the number of cells needed for cell therapy applications far exceeds the number of cells available from donated livers. The ability to implant progenitor cell populations that can form liver tissue in situ, or can be differentiated in vitro would be a major advance in current cell-based therapies. In addition, and importantly for this application, the ability to utilize a non-hepatic progenitor cell to mimic hepatocytes in vitro would enable the scale-up production of cells for bioartifical liver assist devices, cell-therapy and drug discovery applications. We demonstrate the feasibility of inducing adipose-derived stromal (ASC) cells to express several features of human hepatocytes such as glycogen storage and expression of liver specific genes. Importantly, we also show that undifferentiated ASCs and ASC-derived hepatic cells engraft robustly into the liver in a mouse model of toxic injury. These data indicate a significant potential for the use of undifferentiated ASCs and ASC-derived hepatic cells as novel and valuable products for cell therapy. PMID: 20458738 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Adipose-derived stem cells enhance peripheral nerve regeneration. J Plast Reconstr Aesthet Surg. 2010 Sep;63(9):1544-52 Authors: di Summa PG, Kingham PJ, Raffoul W, Wiberg M, Terenghi G, Kalbermatten DF Traumatic injuries resulting in peripheral nerve lesions often require a graft to bridge the gap. Although autologous nerve auto-graft is still the first-choice strategy in reconstructions, it has the severe disadvantage of the sacrifice of a functional nerve. Cell transplantation in a bioartificial conduit is an alternative strategy to create a favourable environment for nerve regeneration. We decided to test new fibrin nerve conduits seeded with various cell types (primary Schwann cells and adult stem cells differentiated to a Schwann cell-like phenotype) for repair of sciatic nerve injury. Two weeks after implantation, the conduits were removed and examined by immunohistochemistry for axonal regeneration (evaluated by PGP 9.5 expression) and Schwann cell presence (detected by S100 expression). The results show a significant increase in axonal regeneration in the group of fibrin seeded with Schwann cells compared with the empty fibrin conduit. Differentiated adipose-derived stem cells also enhanced regeneration distance in a similar manner to differentiated bone marrow mesenchymal stem cells. These observations suggest that adipose-derived stem cells may provide an effective cell population, without the limitations of the donor-site morbidity associated with isolation of Schwann cells, and could be a clinically translatable route towards new methods to enhance peripheral nerve repair. PMID: 19828391 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Surface grafting thermoresponsive PEO-PPO-PEO chains. J Tissue Eng Regen Med. 2010 Oct 8; Authors: Malal R, Malal M, Cohn D The objective of this study was to engineer surfaces comprising covalently bound polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) chains, able to coil and uncoil in aqueous media, as a function of temperature. Thermoresponsive surfaces can be used in diverse areas, such as tissue engineering and 'on-command' drug delivery. The grafting scheme was exemplified using a poly(ethylene terephthalate) (PET) film and started with the exposure of the substrate to plasma of ammonia, whereby amine groups were formed on the film. In the next stage, the amine moieties reacted with the hydroxyterminated thermoresponsive PEO-PPO-PEO triblocks via the hexamethylene diisocyanate (HDI) coupling agent. XPS analysis of the PET film after being exposed to plasma of ammonia revealed substantial amounts of nitrogen, as revealed by the sizeable N1s peak observed at 400.2 eV. A large increase in the C1s ether peak at 286.5 eV was apparent after binding the PEO-PPO-PEO triblocks to the substrate. These findings were confirmed by FTIR spectroscopy and supported by water contact angle measurements. PEO-PPO-PEO triblocks were chain extended by reacting them with HDI, whereby longer polyether urethane chains were formed. The long thermoresponsive chains produced (P-F127) were then tethered to the PET surface, following the procedure used to graft the shorter F127 triblocks. The thermoresponsiveness of the surface was demonstrated by measuring the water contact angle of the P-F127-containing surfaces as a function of temperature. Copyright © 2010 John Wiley & Sons, Ltd. PMID: 20936602 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Hierarchically structured, hyaluronic acid-based hydrogel matrices via the covalent integration of microgels into macroscopic networks. Soft Matter. 2010 Jun 15;6(20):5045-5055 Authors: Jha AK, Malik MS, Farach-Carson MC, Duncan RL, Jia X We aimed to develop biomimetic hydrogel matrices that not only exhibit structural hierarchy and mechanical integrity, but also present biological cues in a controlled fashion. To this end, photocrosslinkable, hyaluronic acid (HA)-based hydrogel particles (HGPs) were synthesized via an inverse emulsion crosslinking process followed by chemical modification with glycidyl methacrylate (GMA). HA modified with GMA (HA-GMA) was employed as the soluble macromer. Macroscopic hydrogels containing covalently integrated hydrogel particles (HA-c-HGP) were prepared by radical polymerization of HA-GMA in the presence of crosslinkable HGPs. The covalent linkages between the hydrogel particles and the secondary HA matrix resulted in the formation of a diffuse, fibrilar interface around the particles. Compared to the traditional bulk gels synthesized by photocrosslinking of HA-GMA, these hydrogels exhibited a reduced sol fraction and a lower equilibrium swelling ratio. When tested under uniaxial compression, the HA-c-HGP gels were more pliable than the HA-p-HGP gels and fractured at higher strain than the HA-GMA gels. Primary bovine chondrocytes were photoencapsulated in the HA matrices with minimal cell damage. The 3D microenvironment created by HA-GMA and HA HGPs not only maintained the chondrocyte phenotype but also fostered the production of cartilage specific extracellular matrix. To further improve the biological activities of the HA-c-HGP gels, bone morphogenetic protein 2 (BMP-2) was loaded into the immobilized HGPs. BMP-2 was released from the HA-c-HGP gels in a controlled manner with reduced initial burst over prolonged periods of time. The HA-c-HGP gels are promising candidates for use as bioactive matrices for cartilage tissue engineering. PMID: 20936090 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Green processing of chitin porous structures for biomedical applications combining ionic liquids and supercritical fluid technology. Acta Biomater. 2010 Oct 6; Authors: S Silva S, Duarte AR, Carvalho AP, Mano JF, Reis RL The application of green chemistry principles in the processing of materials for advanced technologies is a continuous increasing research field. In this work chitin-porous materials were developed combining the processing of chitin using ionic liquids (IL), as green solvent together with the use of supercritical fluid technology (SCF) as clean technology. Chitin was dissolved in 1-butyl-3-imidazolium acetate, followed by regeneration of polymer in ethanol in specific moulds. The IL removal was performed using soxhlet extraction and successive steps of extraction with SCF using carbon dioxide/ethanol ratios of 50/50 and 70/30. The developed chitin-based porous structures (ChIL) can be classified as mesoporous materials, with very low density and high porosity. The cytotoxicity of ChIL extracts using L929 fibroblast-like cells was investigated, and the results demonstrated that the produced materials have extremely low cytotoxicity levels. Therefore, the findings suggest that the chitin porous structures may be potential candidates for relevant biomedical applications, including tissue engineering. PMID: 20933617 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Organic bioelectronics in nanomedicine. Biochim Biophys Acta. 2010 Oct 6; Authors: Svennersten K, Larsson KC, Berggren M, Richter-Dahlfors A BACKGROUND: Nanomedicine is a research area with potential to shape, direct, and change future medical treatments in a revolutionary manner over the next decades. While the common goal with other fields of biomedicine is to solve medical problems, this area embraces an increasing number of technology platforms as they become miniaturized. Organic electronics has over the past two decades developed into an exciting and thriving area of research. SCOPE OF REVIEW: Today, the organic electronics field stands at the interface with biology. As the area of organic bioelectronics advances, it holds promise to make major contributions to nanomedicine. The progress made in this direction is the topic of this review. MAJOR CONCLUSIONS: We describe the inherent features of conducting polymers, and explain the usefulness of these materials as active scaffolds in cell biology and tissue engineering. We also explain how the combined ionic and electronic conductive nature of the polymers is used to precisely control the delivery of signal substances. This unique feature is key in novel devices for chemical communication with cells and tissues. GENERAL SIGNIFICANCE: This review highlights the results from the creative melting pot of interdisciplinary research in organic bioelectronics. PMID: 20933573 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Electrospun Chitosan-graft-poly (ɛ-caprolactone)/Poly (ɛ-caprolactone) Cationic Nanofibrous Mats as Potential Scaffolds for Skin Tissue Engineering. Int J Biol Macromol. 2010 Oct 6; Authors: Chen H, Huang J, Yu J, Liu S, Gu P This research is aimed to develop cationic nanofibrous mats with improved cellular adhesion profiles and stability of three-dimensional fibrous structure as potential scaffolds for skin tissue engineering. Firstly, amino-remained chitosan-graft-poly (ɛ-caprolactone) (CS-g-PCL) was synthesized with a facile one-step manner by grafting ɛ-caprolactone oligomers onto the hydroxyl groups of CS via ring-opening polymerization by using methanesulfonic acid as solvent and catalyst. And then, CS-g-PCL/PCL nanofibrous mats were obtained by electrospinning of CS-g-PCL/PCL mixed solution. Scanning electron microscopy (SEM) images showed that the morphologies and diameters of the nanofibers were mainly affected by the weight ratio of CS-g-PCL to PCL. The enrichment of amino groups on the nanofiber surface was confirmed by X-ray photoelectron spectroscopy (XPS). With the increase of CS-g-PCL in CS-g-PCL/PCL nanofiber, the content of amino groups on the nanofiber surface increased, which resulted in the increase of zeta-potential of nanofibers. Studies on cell-scaffold interaction were carried out by culturing mouse fibroblast cells (L929) on CS-g-PCL/PCL nanofibrous mats with various content of CS-g-PCL by assessing the growth, proliferation and morphologies of cells. The results of MTS assay and SEM observation showed that CS-g-PCL/PCL (2/8) mats with a moderate surface zeta-potential (ζ=3mV) were the best in promoting the cell attachment and proliferation. Toluidene blue staining further confirmed that L929 cells grew well and exhibited a normal morphology on the CS-g-PCL/PCL (2/8) mats. These results suggested the potential utilization of CS-g-PCL/PCL (2/8) nanofibrous mats for skin tissue engineering. PMID: 20933540 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Three-dimensional constructs induce high cellular activity: Structural stability and the specific production of proteins and cytokines. Biochem Biophys Res Commun. 2010 Oct 6; Authors: Kadowaki K, Matsusaki M, Akashi M The specific properties responsible for the stability and function induced by three-dimensional (3D) cellular constructs were evaluated and compared to a monolayer structure. 3D-cellular multilayers composed of human fibroblast cells (FCs) and human umbilical vascular endothelial cells (ECs) were fabricated by a hierarchical cell manipulation technique. Interestingly, the ECs adhered homogeneously onto four-layered (4L) FCs, and tight-junction formation was widely observed at the centimeter scale, while heterogeneous EC domain structures were observed on the monolayered (1L) FCs. The production of heat shock protein70 (Hsp70) and interleukin-6 (IL-6) from the cellular structures were investigated to elucidate any 3D-structural effect on cellular function. The Hsp70 expression of the ECs decreased after adhesion onto the 4L-FC structure as compared with the EC monolayer. Surprisingly, the Hsp70 production response to heat shock increased drastically by approximately 10-fold as compared with a non-heat shock by 3D structure formation, whereas the monolayer structures showed no change. Moreover, the production of the inflammatory cytokine IL-6 decreased significantly depending on the layer number of FCs. To the best of our knowledge, this is the first report on a basic, 3D-structural effect on cellular stability and function. These findings could be important for not only tissue engineering, but also for basic cell biology. PMID: 20933501 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A multi-step method for preparation of porcine small intestinal submucosa (SIS). Biomaterials. 2010 Oct 6; Authors: Luo JC, Chen W, Chen XH, Qin TW, Huang YC, Xie HQ, Li XQ, Qian ZY, Yang ZM Porcine small intestinal submucosa (SIS) has been widely used in repairing various tissues and organs. Despite this, some SIS products have the capacity to cause variable inflammatory responses after implantation resulting in severe adverse effects due to porcine cell existence. In this study, we described a multi-step method including mechanical disassociation, degrease, enzyme digestion, detergent treatment, freeze-drying and sterilization by irradiation for preparation of SIS. The efficacy of acellularization was evaluated by histological observation and the content of porcine immunoreceptor DAP12 gene. The change of growth factors contents within SIS accompanying with decellularization was quantitatively assessed by ELISA. Inflammatory reaction of SIS implanted subcutaneously in a rat was investigated. The histological examination revealed no remaining cells after enzyme digestion. Moreover, qPCR analysis demonstrated that the content of a porcine immunoreceptor gene DAP12 DNA in final SIS product (SISv) was only 1.05% of that in SIS samples (SISi) prepared by mechanical disassociation. Degrease with methanol/chloroform dramatically reduced the contents of VEGF, b-FGF, TGF-β, and TNF-α within SISii, but further treatment could not significantly reduced the contents of growth factors. SIS implanted into rats showed that inflammatory cells was more accumulated surrounded to SISi at 1, and 2 weeks, but reduced in SISv samples. The degree of inflammatory reaction for SISv was significantly less than that of SISi. PMID: 20933271 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Macrophage differentiation and polarization on a decellularized pericardial biomaterial. Biomaterials. 2010 Oct 7; Authors: Ariganello MB, Simionescu DT, Labow RS, Michael Lee J The monocyte-derived macrophage (MDM), present at biomaterial implantations, can increase, decrease or redirect the inflammatory and subsequent wound healing process associated with the presence of a biomaterial. Understanding MDM responses to biomaterials is important for improved prediction and design of biomaterials for tissue engineering. This study analyzed the direct differentiation of monocytes on intact, native collagen. Human monocytes were differentiated on decellularized bovine pericardium (DBP), polydimethylsiloxane (PDMS) or polystyrene (TCPS) for 14 d. MDMs on all surfaces released high amounts of MMP-9 compared to MMP-2 and relatively little MMP-1. MDMs differentiated on DBP released more MMP-2, but less acid phosphatase activity. MDMs on all three surfaces released low amounts of cytokines, although substrate differences were found: MDMs on DBP released higher amounts of IL-6, IL-8, and MCP-1 but lower amounts of IL-10 and IL-1ra. This research provides evidence that MDMs on decellularized matrices may not be stimulated towards an activated, inflammatory phenotype, supporting the potential of decellularized matrices for tissue engineering. This study also demonstrated that the differentiation surface affects MDM phenotype and therefore study design of macrophage interactions with biomaterials should scrutinize the specific macrophage culture method utilized and its effects on macrophage phenotype. PMID: 20933269 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Bone tissue engineering bioreactors: Dynamic culture and the influence of shear stress. Bone. 2010 Oct 4; Authors: Yeatts A, Fisher JP A bone tissue engineering strategy involving the in vitro expansion of cells on a scaffold prior to implantation into the body represents a promising alternative to current clinical treatments. In order to improve in vitro culture, bioreactor systems have been widely researched for bone tissue engineering purposes. Spinner flask, rotating wall bioreactors, and perfusion systems have all been the focus of experiments and each system has advantages and disadvantages. This review seeks to summarize these efforts and provide the current status of research in this area. Research using spinner flasks and rotating wall bioreactors is discussed, but focus is placed on perfusion bioreactor systems. While spinner flasks and rotating wall bioreactors have been shown to improve in vitro culture conditions by increasing homogeneity of nutrients in the media, perfusion systems expose cells to shear stress and more efficiently enhance nutrient transfer. Enhanced mineralized matrix deposition and enhancement of osteoblastic signal expression in response to culture in these systems have been widely reported. This review provides analysis of the causes of these changes in signal expression as well as reports on bioreactor systems that have been commercialized. PMID: 20932947 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Injectable Hydrogel Scaffold from Decellularized Human Lipoaspirate. Acta Biomater. 2010 Oct 4; Authors: Young DA, Ibrahim DO, Hu D, Christman KL Soft tissue fillers are rapidly gaining popularity for aesthetic improvements or repair of adipose tissue deficits. Several injectable biopolymers have been investigated for this purpose but often face rapid resorption or limited adipogenesis, and do not mimic the native adipose extracellular matrix (ECM). We have generated an injectable adipose matrix scaffold by efficiently removing both the cellular and lipid contents of human lipoaspirate. The decellularized material retained a complex composition of peptides and glycosaminoglycans found in native adipose ECM. This matrix can be further processed by solubilizing the extracted ECM to generate a thermally-responsive hydrogel that self-assembles upon subcutaneous injection. This hydrogel also supports the growth and survival of patient matched adipose-derived stem cells in vitro. The development of an injectable hydrogel from human lipoaspirate represents a minimally-invasive option for adipose tissue engineering in terms of both the collection of source material and delivery of the scaffold. PMID: 20932943 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Recombinant self-assembling peptides as biomaterials for tissue engineering. Biomaterials. 2010 Oct 5; Authors: Kyle S, Aggeli A, Ingham E, McPherson MJ Synthetic nanostructures based on self-assembling systems that aim to mimic natural extracellular matrix are now being used as substrates in tissue engineering applications. Peptides are excellent starting materials for the self-assembly process as they can be readily synthesised both chemically and biologically. P(11)-4 is an 11 amino acid peptide that undergoes triggered self-assembly to form a self-supporting hydrogel. It exists as unimers of random coil conformations in water above pH 7.5 but at low pH adopts an antiparallel β-sheet conformation. It also self-assembles under physiological conditions in a concentration-dependent manner. Here we describe an unimer P(11)-4 production system and the use of a simple site-directed mutagenesis approach to generate a series of other P(11)-family peptide expression vectors. We have developed an efficient purification strategy for these peptide biomaterials using a simple procedure involving chemical cleavage with cyanogen bromide then repeated filtration, lyophilisation and wash steps. We report peptide-fusion protein yields of ca. 4.64 g/L and we believe the highest reported recovery of a recombinant self-assembling peptide at 203 mg/L of pure recombinant P(11)-4. This peptide forms a self-supporting hydrogel under physiological conditions with essentially identical physico-chemical properties to the chemically synthesised peptide. Critically it also displays excellent cytocompatibility when tested with primary human dermal fibroblasts. This study demonstrates that high levels of a series of recombinant self-assembling peptides can be purified using a simple process for applications as scaffolds in tissue engineering. PMID: 20932572 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Thermoresponsive unimolecular micelles with a hydrophobic dendritic core and a double hydrophilic block copolymer shell. J Colloid Interface Sci. 2010 Sep 17; Authors: Luo S, Ling C, Hu X, Liu X, Chen S, Han M, Xia J Biocompatible stimuli-responsive unimolecular polymeric micelles have attracted much interest due to their unique structures and potential applications in biomedical fields such as drug delivery and tissue engineering. Here, we report the preparation of dendritic unimolecular polymeric micelles with temperature sensitive shells via reversible addition-fragmentation transfer (RAFT) technique. A multi-arm star amphiphilic copolymer (H40-PDEA) with a hydrophobic hyperbranched polyester (Boltorn H40) as the core and the grafted poly(N,N-diethylacrylamide) (PDEA) as the shell was prepared using H40 based macroRAFT agent. And a dendritic unimolecular polymer (H40-PDEA-PDMA) with a double hydrophilic block copolymer (DHBC) [PDEA-b-poly(2-(dimethylamino)ethyl methacrylate) (PDEA-b-PDMA)] as the dual thermoresponsive shells was synthesized by H40-PDEA based macroRAFT agent. Both H40-PDEA and H40-PDEA-PDMA have a reversible phase transition behavior in aqueous solution. In particular, the unimolecular polymeric micelles H40-PDEA-PDMA with double thermoresponsive shells exhibit a two-stage phase transition behavior. Laser light scattering (LLS), UV-vis transmittance, excimer fluorescence measurements, and micro-differential scanning calorimetry (micro-DSC) were used in combination to probe the conformational changes of chains located at the inner layer and outer corona during the phase transition process. PMID: 20932538 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Coculture of osteoblasts and endothelial cells: optimization of culture medium and cell ratio. Tissue Eng Part C Methods. 2010 Oct 8; Authors: Ma J, van den Beucken JJ, Yang F, Both S, Cui F, Pan J, Jansen J Vascularization strategies in cell-based bone tissue engineering depend on optimal culture conditions. The present study aimed to determine optimal cell culture medium and cell ratio for cocultures of human marrow stromal cells (HMSCs) and human umbilical vein endothelial cells (HUVECs) in view of both osteogenic and angiogenic outcome parameters upon 2D and 3D culture conditions. Cultures were performed in four different media: osteoblastic cell proliferation medium, osteogenic medium, endothelial medium, and a 1:1 mixture of the latter two media. Mineralization within the cocultures was observed only in osteogenic medium. Subsequent experiments in osteogenic medium showed that alkaline phosphatase activity, mineralization, and CD31+ staining were highest for cocultures at a 50:50 HMSCs/HUVECs ratio. Therefore, the results from the present study show that a HMSCs/HUVECs coculture ratio of 50:50 in osteogenic medium is the best combination to obtain both osteogenic and angiogenic differentiation. PMID: 20932081 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Ecto-mesenchymal stem cells from dental pulp are committed to differentiate into active melanocytes. Eur Cell Mater. 2010;20:295-305 Authors: Paino F, Ricci G, De Rosa A, D'Aquino R, Laino L, Pirozzi G, Tirino V, Papaccio G Dental pulp stem cells (DPSCs) are multipotent stem cells derived from neural crest and mesenchyme and have the capacity to differentiate into multiple cell lineages. It has already been demonstrated that DPSCs differentiate into melanocyte-like cells but only when cultivated in a specific melanocyte differentiating medium. In this study we have shown, for the first time, that DPSCs are capable of spontaneously differentiating into mature melanocytes, which display molecular and ultrastructural features of full development, including the expression of melanocyte specific markers and the presence of melanosomes up to the terminal stage of maturation. We have also compared the differentiating features of DPSCs grown in different culture conditions, following the timing of differentiation at molecular and cytochemical levels and found that in all culture conditions full development of these cells was obtained, although at different times. The spontaneous differentiating potential of these cells strongly suggests their possible applications in regenerative medicine. PMID: 20931491 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Endo180 and MT1-MMP are involved in the phagocytosis of collagen scaffolds by macrophages and is regulated by interferon-gamma. Eur Cell Mater. 2010;20:197-209 Authors: Ye Q, Xing Q, Ren Y, Harmsen MC, Bank RA Subcutaneously implanted disks of hexamethylenediisocyanate or glutaraldehyde cross-linked sheep collagen (referred to as HDSC and GDSC, respectively) in mice show large differences in degradation rate. Although comparable numbers of macrophages are seen in HDSC and GDSC, phagocytosis of collagen by macrophages occurred only in GDSC. The molecular mechanisms involved in the phagocytosis of collagen by macrophages are essentially unknown. Immunofluorescence and RT-PCR showed that Endo180 was expressed in GDSC only. TissueFaxs showed that Endo180 co-localized with MT1-MMP on F4÷80 positive cells, which is likely responsible for the phagocytosis in GDSC. RT-PCR further showed that Endo180 expression correlated with high levels of IFN-γ mRNA. In vitro, IFN-γ induced the expression Endo180 and MT1-MMP in murine macrophages cultured on collagen type I (although too high levels of IFN-γ dampened the expression of Endo180 and MT1-MMP). Moreover, the expression of Endo180 and MT1-MMP induced by IFN-γ can be inhibited through IL-10. The differences in microenvironment between GDSC and HDSC (high IFN-γ and low IL-10 levels in GDSC, low IFN-γ and high IL-10 levels in HDSC) provide an explanation why phagocytosis of collagen by macrophages is only seen in GDSC. In summary, we show for the first time that the IFN-γ dependent co-expression of Endo180 and MT1-MMP on macrophages coincides with collagen phagocytosis, thus providing evidence that the mechanism of collagen phagocytosis operating in the foreign body reaction by macrophages is comparable with the mechanism of intracellular collagen degradation by fibroblasts seen under physiological conditions. PMID: 20931490 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of cryopreservation on cell proliferation and immunogenicity of transplanted human heart cells. Ann Thorac Cardiovasc Surg. 2010 Apr;16(2):105-12 Authors: Yokomuro H, Shiono N, Ozawa T, Fujii T, Watanabe Y, Koyama N, Okada M Background: Cell preservation is essential for successful cell transplantation and/or tissue engineering. We examined the effects of cryopreservation on the transplantation of human heart cells. Methods: Cells isolated from human atrial tissues were cultured for 15 days (control group), cryopreserved for 1 week, and rapidly thawed and cultured for 15 days. Proliferation was compared among control and cryopreserved cells or tissues by constructing growth curves. Growth factors, cytokines, biochemical features, and cell cycle phase were measured immediately before and after cryopreservation, and immunogenicity was evaluated from growth curves generated from heart cells after 7 days in mixed-lymphocyte culture. Control or cryopreserved cells were transplanted into rat connective tissues and evaluated histologically 2 weeks later. Results: Cryopreserved cells proliferated more effectively than control cells. Levels of basic fibroblast growth factor and transforming growth factor-β1 were significantly higher, and those of interleukin (IL)-6 and IL-8 were significantly lower after cryopreservation. Fewer peripheral blood lymphocytes were produced in cryopreserved cells than in noncryopreserved cells, and the cell cycle phase of cryopreserved heart cells shifted primarily to G2 + M from G1 + G0. Noncryopreserved and cryopreserved cells both survived in connective tissue. Conclusion: Human atrial cells can be cultured, cryopreserved, and transplanted. Cryopreservation might increase the proliferation of human cells and tissues and also reduce the immunogenicity of heart cells. PMID: 20930663 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | New trends in MRI of cartilage: Advances and limitations in small animal studies. Biomed Mater Eng. 2010 Jan 1;20(3):189-94 Authors: Goebel JC, Pinzano A, Grenier D, Perrier AL, Henrionnet C, Galois L, Gillet P, Beuf O Due to the actual interest for bioengineering in the osteoarthritis (OA) healing context, researchers need accurate qualitative and quantitative methodologies to evaluate in vivo the integration and functionality of their cartilage-like biomaterials. As in clinical diagnostic strategies, advances in Magnetic Resonance Imaging (MRI) seem promising for non-vulnerant assessments of articular cartilage bio-architecture and morphology in small animal models. These experimental models are commonly used to monitor the physiopathology of OA and to evaluate therapeutic responses mediated by chondroprotective drugs or tissue engineering. Nowadays, the application of MR protocols to in vivo small animal cartilage imaging is achievable with the development of high magnetic fields and the adaptation of methodologies to reach the required spatial resolution and contrast. The purpose of this article is to summarize these current MRI strategies used for in vivo small animal articular cartilage assessments. PMID: 20930327 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Original approach for cartilage tissue engineering with mesenchymal stem cells. Biomed Mater Eng. 2010 Jan 1;20(3):167-74 Authors: Tritz-Schiavi J, Charif N, Henrionnet C, de Isla N, Bensoussan D, Magdalou J, Benkirane-Jessel N, Stoltz JF, Huselstein C Cartilage tissue engineering gives the ability to product adaptable neocartilage to lesion with autologous cells. Our work aimed to develop a stratified scaffold with a simple and progressive spraying build-up to mimic articular cartilage environment. An Alginate/Hyaluronic Acid (Alg/HA) hydrogel seeded with human Mesenchymal Stem Cells (hMSC) was construct by spray. First, cells repartition and actin organization were study with confocal microscopy. Then, we analyzed cells viability and finally, metabolic activity. Our results indicated a homogenous cells repartition in the hydrogel and a pericellular actin repartition. After 3 days of culture, we observed about 52% of viable cells in the scaffold. Then, from day 7 until the end of culture (D28), the proportion of living cells and their metabolic activity increased, what indicates that culture conditions are not harmful for the cells.We report here that sprayed method allowed to product a scaffold with hMSCs that confer a favorable environment for neocartilage construction: 3D conformation and ability of cells to increase their metabolic activity, therefore with few impact on hMSCs. PMID: 20930324 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Cartilage tissue engineering: From hydrogel to mesenchymal stem cells. Biomed Mater Eng. 2010 Jan 1;20(3):159-66 Authors: Merceron C, Portron S, Masson M, Fellah BH, Gauthier O, Lesoeur J, Chérel Y, Weiss P, Guicheux J, Vinatier C Articular cartilage does not repair itself spontaneously. To promote its repair, the transfer of stem cells from adipose tissue (ATSC) using an injectable self-setting cellulosic-hydrogel (Si-HPMC) appears promising. In this context, the objective of this work was to investigate the influence of in vitro chondrogenic differentiation of ATSC on the in vivo cartilage formation when combined with Si-HPMC. In a first set of experiments, we characterized ATSC for their ability to proliferate, self renew and express typical mesenchymal stem cell surface markers. Then, the potential of ATSC to differentiate towards the chondrogenic lineage and the optimal culture conditions to drive this differentiation were evaluated. Real-time RT-PCR and histological analysis for sulphated glycosaminoglycans and type II collagen revealed that 3-dimensional culture and hypoxic condition favored ATSC chondrogenesis regarding mRNA expression level and the corresponding proteins production. In order to assess the phenotypic stability of chondrogenically-differentiated ATSC, real-time RT-PCR for specific terminal chondrogenic markers and alkaline phosphatase activity assay were performed. In addition to promote chondrogenesis, our culture conditions seem to prevent the terminal differentiation of ATSC. Histological examination of ATSC/Si-HPMC implants suggested that the in vitro chondrogenic pre-commitment of ATSC in monolayer is sufficient to obtain cartilaginous tissue in vivo. PMID: 20930323 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Chondrogenic potential of bone marrow- and adipose tissue-derived adult human mesenchymal stem cells. Biomed Mater Eng. 2010 Jan 1;20(3):145-58 Authors: Ronzière MC, Perrier E, Mallein-Gerin F, Freyria AM Regarding cartilage repair, tissue engineering is currently focusing on the use of adult mesenchymal stem cells (MSC) as an alternative to autologous chondrocytes. The potential of stem cells from various tissues to differentiate towards the chondrogenic phenotype has been investigated and it appears that the most common and studied sources are bone marrow (BM) and adipose tissue (AT) for historical and easy access reasons. In addition to three dimensional environment, the presence of member(s) of the transforming growth factor (TGF-β family and low oxygen tension have been reported to promote the in vitro differentiation of MSCs. Our work aimed at characterizing and comparing the degree of chondrogenic differentiation of MSCs isolated from BM and AT cultured in the same conditions. We also further aimed at and at determining whether hypoxia (2% oxygen) could affect the chondrogenic potential of AT-MSCs. Cells were first expanded in the presence of FGF-2, then harvested and centrifuged to allow formation of cell pellets, which were cultured in the presence of TGF-β3 and/or Bone Morphogenetic Protein-2 (BMP-2) and with 2 or 20% oxygen tension, for 24 days. Markers of the chondrocyte (COL2A1, AGC1, Sox9) and hypertrophic chondrocyte (COL10A1, MMP-13) were monitored by real-time PCR and/or by immunohistological staining. Our data show that BMP-2/TGF-β3 combination is the best culture condition to induce the chondrocyte phenotype in pellet cultures of BM and AT-MSCs. Particularly, a switch in the expression of the pre-chondrogenic type IIA form to the cartilage-specific type IIB form of COL2A1 was observed. A parallel increase in gene expression of COL10A1 and MMP-13 was also recorded. However when AT-MSCs were cultured in hypoxia, the expression of markers of hypertrophic chondrocytes decreased when BMP-2/TGF-β3 were present in the medium. Thus it seems that hypoxia participates to the control of AT-MSCs chondrogenesis. Altogether, these cellular model systems will help us to investigate further the potential of different adult stem cells for cartilage engineering. PMID: 20930322 [PubMed - in process] | | | | | | | | | |  | |  | |  |
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