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| Differentiation of type 1 T regulatory (Tr1) cells by tolerogenic DC-10 requires the IL-10-dependent ILT4/HLA-G pathway.
May 8, 2010 at 6:40 AM
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| | Differentiation of type 1 T regulatory (Tr1) cells by tolerogenic DC-10 requires the IL-10-dependent ILT4/HLA-G pathway. Blood. 2010 May 6; Authors: Gregori S, Tomasoni D, Pacciani V, Scirpoli M, Battaglia M, Magnani CF, Hauben E, Roncarolo MG Type 1 T regulatory (Tr1) cells suppress immune responses in vivo and in vitro and play a key role in maintaining tolerance to self and non-self antigens. Interleukin-10 (IL-10) is the crucial driving factor for Tr1 cell differentiation, but the molecular mechanisms underlying this induction remain unknown. We identified and characterized a subset of IL-10-producing human DC, termed DC-10, which are present in vivo and can be induced in vitro in the presence of IL-10. DC-10 are CD14(+),CD16(+),CD11c(+),CD11b(+),HLA-DR(+),CD83(+),CD1a(-),CD1c(-), express the Ig-like transcripts (ILT)2, ILT3, ILT4, and HLA-G antigen, display high levels of CD40 and CD86 and up-regulate CD80 following differentiation in vitro. DC-10 isolated from peripheral blood or generated in vitro are potent inducers of antigen-specific IL-10-producing Tr1 cells. Induction of Tr1 cells by DC-10 is IL-10-dependent and requires the ILT4/HLA-G signaling pathway. Our data indicate that DC-10 represen! t a novel subset of tolerogenic DC which secrete high levels of IL-10, express ILT4 and HLA-G, and have the specific function to induce Tr1 cells. PMID: 20448110 [PubMed - as supplied by publisher] | | |
| Immunological and regenerative properties of cord blood stem cells.
May 8, 2010 at 6:40 AM
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| | Immunological and regenerative properties of cord blood stem cells. Clin Immunol. 2010 May 4; Authors: Francese R, Fiorina P Cord blood stem cells (CB-SCs) have shown impressive immunological and regenerative capabilities. In this review, we intend to review the state-of-the-art knowledge on CB-SCs characteristics and function as well as immunological and regenerative properties. We report an itemized classification of CB-SCs populations, which is important to better understand which tissues can be replaced using CB-SCs and how the generation of induced pluripotent stem cells from CB-SCs is changing the field. Furthermore, we will discuss new findings on the immunosuppressive capability of CB-SCs in autoimmune disease (e.g., type 1 diabetes). Our review will demonstrate how CB-SCs could become a powerful tool not only for regenerative medicine but for autoimmune and inflammatory diseases as well. PMID: 20447870 [PubMed - as supplied by publisher] | | |
| Multilayer microfluidic PEGDA hydrogels.
May 8, 2010 at 6:40 AM
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| | Multilayer microfluidic PEGDA hydrogels. Biomaterials. 2010 May 4; Authors: Cuchiara MP, Allen AC, Chen TM, Miller JS, West JL Development of robust 3D tissue analogs in vitro is limited by passive, diffusional mass transport. Perfused microfluidic tissue engineering scaffolds hold the promise to improve mass transport limitations and promote the development of complex, metabolically dense, and clinically relevant tissues. We report a simple and robust multilayer replica molding technique in which poly(dimethylsiloxane) (PDMS) and poly(ethylene glycol) diacrylate (PEGDA) are serially replica molded to develop microfluidic PEGDA hydrogel networks embedded within independently fabricated PDMS housings. We demonstrate the ability to control solute-scaffold effective diffusivity as a function of solute molecular weight and hydrogel concentration. Within cell laden microfluidic hydrogels, we demonstrate increased cellular viability in perfused hydrogel systems compared to static controls. We observed a significant increase in cell viability at all time points greater than zero at distances up ! to 1 mm from the perfused channel. Knowledge of spatiotemporal mass transport and cell viability gradients provides useful engineering design parameters necessary to maximize overall scaffold viability and metabolic density. This work has applications in the development of hydrogels as in vitro diagnostics and ultimately as regenerative medicine based therapeutics. PMID: 20447685 [PubMed - as supplied by publisher] | | |
| Gene transfer into human cord blood-derived CD34(+) cells by adeno-associated viral vectors.
May 8, 2010 at 6:40 AM
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| | Gene transfer into human cord blood-derived CD34(+) cells by adeno-associated viral vectors. Exp Hematol. 2010 May 3; Authors: Schuhmann NK, Pozzoli O, Sallach J, Huber A, Avitabile D, Perabo L, Rappl G, Capogrossi MC, Hallek M, Pesce M, Büning H OBJECTIVE: Bone marrow-derived CD34(+) cells are currently used in clinical trials in patients with ischemic heart disease. An option to enhance activity of injected progenitors may be offered by genetic engineering of progenitor cells with angiogenic growth factors. Adeno-associated viral vectors (rAAV) have emerged as a leading gene transfer systems. In contrast to other vector systems in use for genetic engineering of CD34(+) cells, rAAV-mediated gene expression does not depend on vector integration. This is relevant for application in regenerative medicine of ischemic tissues, where transient transgene expression is likely sufficient to achieve therapeutic benefits. METHODS: We compared three different human AAV serotypes, packaged as pseudo-types by a helper virus-free production method for their transduction efficiency in human (h) cord blood-derived CD34(+) cells. We further assessed the impact of vector genome conformation, of alpha(v)beta(5) and alpha(5)b! eta(1) integrin availability and of the transcription-modulating drugs retinoic acid and Trichostatin A on rAAV-mediated hCD34(+) cell transduction. RESULTSAND CONCLUSIONS: We provide for the first time evidence that hCD34(+) cells can be reproducibly transduced with high efficiency by self-complementary rAAV2 without inducing cytotoxicity or interfering with their differentiation potential. We further show the involvement of alpha(5)beta(1) integrin as a crucial AAV2 internalization receptor and a function for transcription-modulating drugs in enhancing rAAV-mediated transgene expression. This study represents a first step forward to translation of a combined cellular/rAAV-based therapy of ischemic disease. PMID: 20447441 [PubMed - as supplied by publisher] | | |
| Slow and sustained release of active cytokines from self-assembling peptide scaffolds.
May 8, 2010 at 6:40 AM
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| | Slow and sustained release of active cytokines from self-assembling peptide scaffolds. J Control Release. 2010 May 3; Authors: Gelain F, Unsworth LD, Zhang S Controlling the cellular microenvironment is thought to be critical for the successful application of biomaterials for regenerative medicine strategies. Self-assembling peptides are proving to be a promising platform for a variety of regenerative medicine applications. Specifically, RADA16-I self-assembling peptides have been successfully used for 3D cell culture, accelerated wound healing, and nerve-repair. Understanding the fundamental mechanisms for protein mobility within, and ultimately release from, this nanostructured system is a critical aspect for controlling cellular activity; studies which are largely lacking within the literature. Herein, we report that designer self-assembling peptide scaffolds facilitate slow and sustained release of active cytokines that are extremely relevant to many areas of regenerative medicine. In addition, multiple diffusive mechanisms are observed to exist for human betaFGF, VEGF and BDNF within RADA16-I and two different RAD! A16-I nanofiber forming peptides with net positive or negative charges located at the C-terminus. In some cases, two populations of diffusing molecules are observed at the molecular level: one diffusing fully within the solvent, and another that exhibits hindered mobility. Results suggest that protein mobility is inhibited by both physical hinderances and charge induced interactions between the protein and peptide nanofibers. Moreover, assays using adult neural stem cells (NSCs) are employed to assess the functional release of active cytokine (betaFGF) up to three weeks. Our results not only provide evidence for long-term molecular release from self-assembling peptide scaffolds but also inspiration for a plethora of slow molecular release strategies for clinical applications. PMID: 20447427 [PubMed - as supplied by publisher] | | |
| Pulmonary hypertension: advances in pathogenesis and treatment.
May 8, 2010 at 6:39 AM
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| | Pulmonary hypertension: advances in pathogenesis and treatment. Br Med Bull. 2010 May 6; Authors: Toshner M, Tajsic T, Morrell NW Pulmonary hypertension is an orphan disease that until recently has received limited attention within the wider medical community. This has changed distinctly in the last 10 years with the advent of new classes of therapy and a renewed interest in mechanisms of pathogenesis. This review utilized information gathered from recent conferences, and a review of the literature was conducted using MedLine and Pubmed. Accepted mechanisms of pathogenesis and currently available treatments are presented. We will discuss interesting new concepts in pathogenesis, including the importance of genetic forms of the disease and in particular the transforming growth factor receptor superfamily and the evolving evidence of the contribution of dysregulated immunity. Areas of research may yield therapeutic benefits in the not-too-distant future, including anti-proliferative therapies and stem cell therapy. PMID: 20447940 [PubMed - as supplied by publisher] | | |
| Bone marrow stem cell therapy for recessive dystrophic epidermolysis bullosa.
May 8, 2010 at 6:39 AM
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| | Bone marrow stem cell therapy for recessive dystrophic epidermolysis bullosa. Dermatol Clin. 2010 Apr;28(2):371-82, xii-xiii Authors: Kiuru M, Itoh M, Cairo MS, Christiano AM Recessive dystrophic epidermolysis bullosa (RDEB) is a severe inherited blistering disease caused by mutations in the type VII collagen gene, resulting in defective anchoring fibrils at the epidermal-dermal junction. At present, no curative treatment for RDEB exists. Mounting evidence on reprogramming of bone marrow stem cells into skin has prompted the authors and others to develop novel strategies for treatment of RDEB. The rationale for bone marrow stem cell therapies for RDEB is based on the evidence that bone marrow-derived cells are guided into becoming skin cells, given the right microenvironment. Preclinical studies in mouse models have shown that wild-type bone marrow-derived cells can ameliorate the phenotype of RDEB and improve survival by restoring the expression of type VII collagen and the anchoring fibrils. At present, several clinical studies are ongoing around the world to study the therapeutic effects of bone marrow stem cell transplantation for ! RDEB. These studies provide a framework for future development of standardized, effective methods for stem cell transplantation to cure severe inherited skin diseases, including RDEB. PMID: 20447506 [PubMed - in process] | | |
| Teaching of direct posterior resin composite restorations in UK dental therapy training programmes.
May 8, 2010 at 6:32 AM
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| | Teaching of direct posterior resin composite restorations in UK dental therapy training programmes. Br Dent J. 2010 May 8;208(9):415-21 Authors: Lynch CD, Wilson NH AIM: With the numbers of dental therapists involved in the delivery of dental care within the UK on the increase, and the trend towards the use of direct resin composites (composites) for the restoration of posterior teeth, this study was undertaken to describe the teaching of posterior composites in dental therapy training programmes in the UK. A secondary aim was to identify differences in techniques for posterior composites taught within these dental therapy training programmes. METHODS: In 2008/9, a questionnaire seeking information on the teaching of posterior composites was distributed by email to 13 centres with dental therapy training programmes in the UK. This questionnaire sought information relating to the teaching of direct posterior composites to dental therapy students, including the amounts of preclinical and clinical teaching in respect of deciduous and permanent teeth, numbers of restorations placed, contraindications to placement, and details in ! respect of operative techniques. RESULTS: Ten completed responses were received (response rate = 77%). In ten programmes, student dental therapists received clinical training in the placement of composite restorations in the occlusal surfaces of premolar and permanent molar teeth, and nine programmes included such training for two and three surface occlusoproximal restorations. The mean proportions of posterior restorations placed clinically by the trainee dental therapists in permanent teeth using dental amalgam and composite were 52% and 46% respectively (range: amalgam = 20-95%; composite = 5-70%). CONCLUSION: With the exception of one programme, the teaching of posterior composites is a well established element of dental therapy training. Some variations were noted in the teaching of clinical techniques between respondent training centres. It is suggested that to ensure harmony in approaches to treatments provided by graduated therapists that training centres look to re! levant consensus documents, such as those of the British Assoc! iation f or the Teaching of Conservative Dentistry. The findings of our study are important for the future provision of oral healthcare, given the growing evidence base in favour of minimally invasive dentistry. PMID: 20448613 [PubMed - in process] | | |
| Endothelial Nitric Oxide Synthase as A Marker for Human Endothelial Progenitor Cells.
May 8, 2010 at 6:32 AM
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| | Endothelial Nitric Oxide Synthase as A Marker for Human Endothelial Progenitor Cells. Tohoku J Exp Med. 2010;221(1):19-27 Authors: Qiao W, Niu L, Liu Z, Qiao T, Liu C Endothelial progenitor cells (EPCs) have been proposed as a promising tool for therapeutic neovascularization, vascular repair, tumor pathology and tissue engineering, though their identification is still a subject of much discussion. EPCs consist of two different subpopulations, termed endothelial cell (EC)-like cells and endothelial outgrowth cells (EOCs). Both types of EPCs are derived from mononuclear cells, but they have different characteristics. Our aim was to characterize and compare the two types of EPCs to find reliable biological features of EPCs that can be used for identification of EPCs. In this study, human peripheral blood mononuclear cells were isolated by density gradient centrifugation and cultured on fibronectin-coated culture plates. While adherent cells were maintained, EC-like cells appeared within 4-7 days of culture, and EOCs developed after 2-3 weeks of culture. EOCs, which were characterized by high proliferation potential, were able to ! form capillary tubes on Matrigel, but not EC-like cells, despite the higher concentrations of three angiogenic cytokines, vascular endothelial growth factor, granulocyte colony-stimulating factor, and interleukin 8, in the conditioned medium of EC-like cells. In contrast, endothelial nitric oxide synthase (eNOS) was expressed in both types of EPCs, and both cell types could produce nitric oxide (NO), as judged by measuring the total amounts of nitrites and nitrates in culture media. In conclusion, the expression of eNOS and the production of NO could be used as common biological features to identify EPCs. These findings provide new insights into the identification of EPCs. PMID: 20448437 [PubMed - as supplied by publisher] | | |
| Comparison of suturing techniques in the formation of collagen scaffold tubes for composite tubular organ tissue engineering.
May 8, 2010 at 6:32 AM
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| | Comparison of suturing techniques in the formation of collagen scaffold tubes for composite tubular organ tissue engineering. Biomed Mater Eng. 2010 Jan 1;20(1):1-11 Authors: Soltysiak P, Höllwarth ME, Saxena AK In order to construct tubes for tissue engineering of composite tubular organs in the gastrointestinal tract, suturing techniques were investigated with regards to (a) type of suture material, (b) state of scaffold, (c) technical variations and (d) changes in scaffold morphology. Collagen scaffolds of 13 mm diameter and 3 mm thickness, in both dry and wet states, were sutured using braided and monofilament sutures. Four suture techniques were employed (a) continuous loop, (b) interrupted loops, (c) interrupted edge sutures and (d) continuous running edge suture. Scanning electron microscopic imaging was performed on the 4 tubes sutured. Monofilament sutures were used for tube formation as braided sutures were unsuitable. Dry scaffolds demonstrated tears during knot tying and fractures when bent around a stent. The interrupted and continuous running edge suture were the most suitable suturing techniques in wet scaffolds; further confirmed by scanning electron micro! scopy imaging. Our approach to tissue engineer segments of the gastrointestinal tract involves cell-seeding on scaffolds to permit attachment in vitro and later wrapping of scaffold layers of heterogeneous cells to create composite tissue. Scaffolds in wet state can be better sutured with monofilament materials using either the interrupted or running continuous edge suture technique. PMID: 20448299 [PubMed - in process] | | |
| Development of a Drug Screening Platform Based on Engineered Heart Tissue.
May 8, 2010 at 6:32 AM
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| | Development of a Drug Screening Platform Based on Engineered Heart Tissue. Circ Res. 2010 May 6; Authors: Hansen A, Eder A, Bönstrup M, Flato M, Mewe M, Schaaf S, Aksehirlioglu B, Schwörer A, Uebeler J, Eschenhagen T Rationale: Tissue engineering may provide advanced in vitro models for drug testing and, in combination with recent induced pluripotent stem cell technology, disease modeling, but available techniques are unsuitable for higher throughput. Objective: Here, we present a new miniaturized and automated method based on engineered heart tissue (EHT). Methods and Results: Neonatal rat heart cells are mixed with fibrinogen/Matrigel plus thrombin and pipetted into rectangular casting molds in which two flexible silicone posts are positioned from above. Contractile activity is monitored video-optically by a camera and evaluated by a custom-made software program. Fibrin-based mini-EHTs (FBMEs) (150 muL, 600 000 cells) were transferred from molds to a standard 24-well plate two hours after casting. Over time FBMEs condensed from a 12x3x3 mm gel to a muscle strip of 8 mm length and, depending on conditions, 0.2 to 1.3 mm diameter. After 8 to 10 days, FBMEs started to rhythmica! lly deflect the posts. Post properties and the extent of post deflection allowed calculation of rate, force (0.1 to 0.3 mN), and kinetics which was validated in organ baths experiments. FBMEs exhibited a well-developed, longitudinally aligned actinin-positive cardiac muscle network and lectin-positive vascular structures interspersed homogeneously throughout the construct. Analysis of a large series of FBME (n=192) revealed high yield and reproducibility and stability for weeks. Chromanol, quinidine, and erythromycin exerted concentration-dependent increases in relaxation time, doxorubicin decreases in contractile force. Conclusions: We developed a simple technique to construct large series of EHT and automatically evaluate contractile activity. The method shall be useful for drug screening and disease modeling. PMID: 20448218 [PubMed - as supplied by publisher] | | |
| The visualisation of vitreous using surface modified poly(lactic-co-glycolic acid) microparticles.
May 8, 2010 at 6:32 AM
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| | The visualisation of vitreous using surface modified poly(lactic-co-glycolic acid) microparticles. Br J Ophthalmol. 2010 May;94(5):648-53 Authors: Chau DY, Tint NL, Collighan RJ, Griffin M, Dua HS, Shakesheff KM, Rose FR AIMS To demonstrate the potential use of in vitro poly(lactic-co-glycolic acid) (PLGA) microparticles in comparison with triamcinolone suspension to aid visualisation of vitreous during anterior and posterior vitrectomy. METHODS PLGA microparticles (diameter 10-60 microm) were fabricated using single and/or double emulsion technique(s) and used untreated or following the surface adsorption of a protein (transglutaminase). Particle size, shape, morphology and surface topography were assessed using scanning electron microscopy (SEM) and compared with a standard triamcinolone suspension. The efficacy of these microparticles to enhance visualisation of vitreous against the triamcinolone suspension was assessed using an in vitro set-up exploiting porcine vitreous. RESULTS Unmodified PLGA microparticles failed to adequately adhere to porcine vitreous and were readily washed out by irrigation. In contrast, modified transglutaminase-coated PLGA microparticles demonstrated! a significant improvement in adhesiveness and were comparable to a triamcinolone suspension in their ability to enhance the visualisation of vitreous. This adhesive behaviour also demonstrated selectivity by not binding to the corneal endothelium. CONCLUSION The use of transglutaminase-modified biodegradable PLGA microparticles represents a novel method of visualising vitreous and aiding vitrectomy. This method may provide a distinct alternative for the visualisation of vitreous whilst eliminating the pharmacological effects of triamcinolone acetonide suspension. PMID: 20447968 [PubMed - in process] | | |
| Multilayer microfluidic PEGDA hydrogels.
May 8, 2010 at 6:32 AM
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| | Multilayer microfluidic PEGDA hydrogels. Biomaterials. 2010 May 4; Authors: Cuchiara MP, Allen AC, Chen TM, Miller JS, West JL Development of robust 3D tissue analogs in vitro is limited by passive, diffusional mass transport. Perfused microfluidic tissue engineering scaffolds hold the promise to improve mass transport limitations and promote the development of complex, metabolically dense, and clinically relevant tissues. We report a simple and robust multilayer replica molding technique in which poly(dimethylsiloxane) (PDMS) and poly(ethylene glycol) diacrylate (PEGDA) are serially replica molded to develop microfluidic PEGDA hydrogel networks embedded within independently fabricated PDMS housings. We demonstrate the ability to control solute-scaffold effective diffusivity as a function of solute molecular weight and hydrogel concentration. Within cell laden microfluidic hydrogels, we demonstrate increased cellular viability in perfused hydrogel systems compared to static controls. We observed a significant increase in cell viability at all time points greater than zero at distances up ! to 1 mm from the perfused channel. Knowledge of spatiotemporal mass transport and cell viability gradients provides useful engineering design parameters necessary to maximize overall scaffold viability and metabolic density. This work has applications in the development of hydrogels as in vitro diagnostics and ultimately as regenerative medicine based therapeutics. PMID: 20447685 [PubMed - as supplied by publisher] | | |
| A New Sol-Gel Process for Producing Na(2)O-Containing Bioactive Glass-Ceramics.
May 8, 2010 at 6:32 AM
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| | A New Sol-Gel Process for Producing Na(2)O-Containing Bioactive Glass-Ceramics. Acta Biomater. 2010 May 3; Authors: Chen QZ, Li Y, Jin LY, Quinn JM, Komesaroff PA The sol-gel process of producing SiO(2)-CaO bioactive glass is well established, but problems remain with the poor mechanical properties of its amorphous form and the bioinertness of its crystalline counterpart. These properties may be improved by incorporating Na(2)O into bioactive glasses, which can result in formation of a hard yet biodegradable crystalline phase from bioactive glasses when sintered. However, production of Na(2)O-containing bioactive glasses by sol-gel methods has proved to be difficult. This work reports a new sol gel process for the production of Na(2)O-containing bioactive glass-ceramics, potentially enabling their use as medical implantation materials. Fine powders of 45S5 (a Na(2)O-containing composition) glass-ceramics have for the first time been successfully synthesized using the sol-gel technique in a water solution under ambient conditions, with a mean particle size being approximately 5 mum. A comparative study of sol-gel derived S70! C30 (a Na(2)O-free composition) and 45S5 glass-ceramic materials revealed that the latter possesses a number of features desirable in biomaterials used for bone tissue engineering, including (1) the crystalline phase Na(2)Ca(2)Si(3)O(9) that couples good mechanical strength with a satisfactory biodegradability, (2) formation of hydroxyapatite which may promote good bone-bonding, and (3) cytocompatibility. In contrast, the sol-gel derived S70C30 glass-ceramics consisted of a virtually inert crystalline phase CaSiO(3). Moreover, amorphous S70C30 largely transited to CaCO(3) with minor hydroxyapatite when immersed in simulated body fluid under the standard tissue culture conditions. In conclusion, sol-gel derived Na(2)O-conatining glass-ceramics have significant advantages over related Na(2)O-free material, having a greatly improved combination of mechanical capability and biological absorbability. PMID: 20447473 [PubMed - as supplied by publisher] | | |
| Slow and sustained release of active cytokines from self-assembling peptide scaffolds.
May 8, 2010 at 6:32 AM
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| | Slow and sustained release of active cytokines from self-assembling peptide scaffolds. J Control Release. 2010 May 3; Authors: Gelain F, Unsworth LD, Zhang S Controlling the cellular microenvironment is thought to be critical for the successful application of biomaterials for regenerative medicine strategies. Self-assembling peptides are proving to be a promising platform for a variety of regenerative medicine applications. Specifically, RADA16-I self-assembling peptides have been successfully used for 3D cell culture, accelerated wound healing, and nerve-repair. Understanding the fundamental mechanisms for protein mobility within, and ultimately release from, this nanostructured system is a critical aspect for controlling cellular activity; studies which are largely lacking within the literature. Herein, we report that designer self-assembling peptide scaffolds facilitate slow and sustained release of active cytokines that are extremely relevant to many areas of regenerative medicine. In addition, multiple diffusive mechanisms are observed to exist for human betaFGF, VEGF and BDNF within RADA16-I and two different RAD! A16-I nanofiber forming peptides with net positive or negative charges located at the C-terminus. In some cases, two populations of diffusing molecules are observed at the molecular level: one diffusing fully within the solvent, and another that exhibits hindered mobility. Results suggest that protein mobility is inhibited by both physical hinderances and charge induced interactions between the protein and peptide nanofibers. Moreover, assays using adult neural stem cells (NSCs) are employed to assess the functional release of active cytokine (betaFGF) up to three weeks. Our results not only provide evidence for long-term molecular release from self-assembling peptide scaffolds but also inspiration for a plethora of slow molecular release strategies for clinical applications. PMID: 20447427 [PubMed - as supplied by publisher] | | |
| HUMAN BONE MARROW-DERIVED CD133+ CELLS DELIVERED TO A COLLAGEN PATCH ON CRYOINJURED RAT HEART PROMOTE ANGIOGENESIS AND ARTERIOGENESIS.
May 8, 2010 at 6:32 AM
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| | HUMAN BONE MARROW-DERIVED CD133+ CELLS DELIVERED TO A COLLAGEN PATCH ON CRYOINJURED RAT HEART PROMOTE ANGIOGENESIS AND ARTERIOGENESIS. Cell Transplant. 2010 May 4; Authors: Pozzobon M, Bollini S, Iop L, De Gaspari P, Chiavegato A, Rossi C, Giuliani S, Fascetti LF, Elvassore N, Sartore S, De Coppi P Transplanting hematopoietic and peripheral blood derived stem/progenitor cells can have beneficial effects in slowing the effects of heart failure. We investigated whether human bone marrow CD133+-derived cells (BM-CD133+ cells) might be used for cell therapy of heart injury in combination with tissue engineering. We examined these cells for: (1) their in vitro capacity to be converted into cardiomyocytes (CMs); and (2) their potential for in vivo differentiation when delivered to a tissue-engineered type I collagen patch placed on injured hearts (Group II). To ensure a microvascular network ready for use by the transplanted cells, cardiac injury and patching were scheduled two weeks before cell injection. The cardiovascular potential of the BM-CD133+ cells was compared with that of a direct injection (Group I) of the same cells in heart tissue damaged according to the same schedule as for Group II. While a small fraction (2+/-0.5%) of BM-CD133+ cells co-cultured ! with rat CMs switched in vitro to a CM-like cell phenotype, in vivo - and in both groups of nude rats transplanted with BM-CD133+ - there was no evidence of any CM differentiation (as detected by cardiac troponin I expression), but there were signs instead of new capillaries and small arterioles. While capillaries prevailed over arterioles in Group II, the opposite occurred in Group I. The transplanted cells further contributed to the formation of new microvessels induced by the patch (Group II) but the number of vessels did not appear superior to the one developed after directly injecting the BM-CD133+ cells into the injured heart. Though chimeric human-rat microvessels were consistently found in the hearts of both Groups I and II, they represented a minority (1.5-2.3%) compared with those of rat origin. Smooth muscle myosin isoform expression suggested that the arterioles achieved complete differentiation irrespective of the presence or absence of the collagen patch.These! findings suggest that: 1) BM-CD133+ cells display a limited p! ropensit y for in vitro conversion to CMs; 2) the preliminarily vascularized bioscaffold did not confer a selective homing and differentiation advantage for the phenotypic conversion of BM-CD133+ cells into CMs; and 3) combined patching and cell transplantation is suitable for angiogenesis and arteriogenesis, but it does not produce better results, in terms of endothelial and smooth muscle cell differentiation, than the "traditional" method of cell injection into the myocardium. PMID: 20447342 [PubMed - as supplied by publisher] | | |
| Detergent decellularization of heart valves for tissue engineering: toxicological effects of residual detergents on human endothelial cells.
May 8, 2010 at 6:32 AM
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| | Detergent decellularization of heart valves for tissue engineering: toxicological effects of residual detergents on human endothelial cells. Artif Organs. 2010 Mar;34(3):206-10 Authors: Cebotari S, Tudorache I, Jaekel T, Hilfiker A, Dorfman S, Ternes W, Haverich A, Lichtenberg A Detergents are powerful agents for tissue decellularization. Despite this, the high toxicity of detergent residua can be a major limitation. This study evaluated the efficacy of detergent removal from decellularized pulmonary valves (PVs) and the consequences of repopulation with human endothelial cells (HECs). Porcine PVs were treated with 1% sodium deoxycholate (SDC), group A; 1% sodium dodecyl sulfate (SDS), group B; and a mixture of 0.5% SDC/0.5% SDS, group C (n = 5 each). After each of 10 succeeding wash cycles (WCs), samples of the washing solution (WS) were analyzed by solid phase extraction and high performance liquid chromatography for the presence of detergents. Metabolic activity of HEC was also assessed in the WS samples (cytotoxicity and MTS assays). Decellularized and washed PVs were reseeded with HEC. Histological analysis demonstrated efficient tissue decellularization in all groups. Detergents' concentration in all WSs decreased exponentially and ! was below 50 mg/L after 6, 8, and 4 WCs in groups A, B, and C, respectively. This concentration resulted in no significant toxic influence on cell cultures, and scaffolds could be efficiently reseeded with HEC. In conclusion, intensive washing of detergent decellularized valvular scaffolds lowers the residual contamination below a hazardous threshold and allows their successful repopulation with HEC for tissue engineering purposes. PMID: 20447045 [PubMed - in process] | | |
| A micro-scale surface-structured PCL scaffold fabricated by a 3D plotter and a chemical blowing agent.
May 8, 2010 at 6:32 AM
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| | A micro-scale surface-structured PCL scaffold fabricated by a 3D plotter and a chemical blowing agent. J Biomater Sci Polym Ed. 2010;21(2):159-70 Authors: Yoon H, Kim GH, Koh YH To study cell responses, polymeric scaffolds with a controllable pore size and porosity have been fabricated using rapid-prototyping methods. However, the scaffolds fabricated by rapid prototyping have very smooth surfaces, which tend to discourage initial cell attachment. Initial cell attachment, migration, differentiation and proliferation are strongly dependent on the chemical and physical characteristics of the scaffold surface. In this study, we propose a three-dimensional (3D) plotting method supplemented with a chemical blowing agent to produce a surface-modified 3D scaffold in which the surface is inscribed with nano- and micro-sized pores. The chemically-blown 3D polymeric scaffold exhibited positive qualities, including the compressive modulus, hydrophilicity and initial cell adhesion. Cell cultures on the scaffolds demonstrated that chondrocytes interacted better with the surface-modified scaffold than with a normal 3D scaffold. PMID: 20092682 [PubMed - indexed for MEDLINE] | | |
| Fibroblast growth factor-1 (FGF-1) loaded microbeads enhance local capillary neovascularization.
May 8, 2010 at 6:32 AM
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| | Fibroblast growth factor-1 (FGF-1) loaded microbeads enhance local capillary neovascularization. J Surg Res. 2010 May 15;160(2):208-12 Authors: Moya ML, Garfinkel MR, Liu X, Lucas S, Opara EC, Greisler HP, Brey EM BACKGROUND: Growth of new blood vessels (neovascularization) occurs naturally in the body, but the slow rate of the process may not be sufficient for survival of engineered tissues and transplanted cells, such as pancreatic islets. For transplanted islets, it is crucial that the transplantation site has sufficient vasculature to support the needs of the islets. Therefore, the specific aim of this research was quantify the effect of FGF-1 incorporation into alginate microbeads on neovascularization of such capsules in an in vivo rat transplant model. MATERIALS AND METHODS: Microbeads loaded with FGF-1 or control beads (beads without FGF-1) were implanted in the rat omental pouch model. Animals were sacrificed 7 d post-implantation. RESULTS: Microbeads loaded with FGF-1 stimulated a significant increase in vascular density compared with control rats implanted with control beads. CONCLUSIONS: These results indicate that alginate microbeads loaded with FGF-1 enhance l! ocal neovascularization around implanted microbeads. These data provide a compelling impetus for experimental pursuit of FGF-loaded alginate microcapsules for vascularization of transplanted islets. PMID: 19959194 [PubMed - indexed for MEDLINE] | | | | 
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