|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | SAN FRANCISCO – A blue-ribbon panel examining California's $3 billion stem cell agency began its second public session this morning with some of its members saying they are impressed by what they have learned so far and with some expressing concern about whether CIRM has enough "bandwidth" to achieve its goals.
Alan Bernstein, chairman of the panel and executive director of the Global HIV | | | | | | | | | | | | | | | | | | | | | | | | | Methods for in vitro generation of human type 1 regulatory T cells. Methods Mol Biol. 2011;677:31-46 Authors: Gregori S, Roncarolo MG, Bacchetta R Type 1 regulatory T (Tr1) cells are adaptive regulatory T cells that are induced in the periphery upon chronic exposure to antigen (Ag) in a tolerogenic environment containing interleukin (IL)-10. Tr1 cells are Ag-specific; they produce high levels of IL-10 and TGF-β in the absence of IL-4 and suppress T-cell responses via a cytokine-dependent mechanism. During the last decade, several protocols have been developed to generate Tr1 cell lines in vitro. In this chapter, we outline protocols to generate non-Ag- and Ag-specific Tr1 cell lines and assays used to characterize Tr1 cell phenotype and functions. PMID: 20941601 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Switching from bone marrow-derived neurons to epithelial cells through dedifferentiation and translineage redifferentiation. Cell Biol Int. 2010 Sep 24;34(11):1075-83 Authors: Liu Y, Jiang X, Kuen Yu M, Dong J, Zhang X, Ling Tsang L, Wa Chung Y, Li T, Chang Chan H While the ability of stem cells to switch lineages has been suggested, the route(s) through which this may happen is unclear. To date, the best characterized adult stem cell population considered to possess transdifferentiation capacity is BM-MSCs (bone marrow mesenchymal stem cells). We investigated whether BM-MSCs that had terminally differentiated into the neural or epithelial lineage could be induced to transdifferentiate into the other phenotype in vitro. Our results reveal that neuronal phenotypic cells derived from adult rat bone marrow cells can be switched to epithelial phenotypic cells, or vice versa, by culture manipulation allowing the differentiated cells to go through, first, dedifferentiation and then redifferentiation to another phenotype. Direct transdifferentiation from differentiated neuronal or epithelial phenotype to the other differentiated phenotype cannot be observed even when appropriate culture conditions are provided. Thus, dedifferentiation appears to be a prerequisite for changing fate and differentiating into a different lineage from a differentiated cell population. PMID: 20939829 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Novel Strategies of Regenerative Medicine Using Chemical Compounds. Curr Med Chem. 2010 Oct 13; Authors: Lasagni L, Sagrinati C, Ronconi E, Angelotti ML, Parente E, Ballerini L, Peired A, Romagnani P Many diseases and/or physical defects due to injury result in the loss of specialized cells within organ systems and lead to organ system dysfunction. The ultimate goal of cell-based therapies is to regenerate and restore normal function. Populations of embryonic, fetal, adult stem cells and inducible pluripotent stem cells generated by reprogramming of adult cells show promise for the treatment of a variety of diseases. In addition, the recent advancements in adult stem cell biology in both normal and pathological conditions have led to the identification of some intrinsic and extrinsic factors that govern the decision between self renewal versus differentiation of tissue-resident adult stem cells. This is of primary importance for the design of an approach of stem cell-based therapy focused on their in vivo modulation by conventional chemical and biological therapeutics capable to stimulate endogenous cell regeneration. Such therapeutics can act in vivo to promote cell survival, proliferation, differentiation, reprogramming and homing of stem cells or can modulate their niches. In this review, we will highlight the burst of recent literature on novel perspectives of regenerative medicine and their possible clinical applications. PMID: 20939819 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Three-dimensional chitin-based scaffolds from Verongida sponges (Demospongiae: Porifera). Part II: Biomimetic potential and applications. Int J Biol Macromol. 2010 Aug 1;47(2):141-5 Authors: Ehrlich H, Steck E, Ilan M, Maldonado M, Muricy G, Bavestrello G, Kljajic Z, Carballo JL, Schiaparelli S, Ereskovsky A, Schupp P, Born R, Worch H, Bazhenov VV, Kurek D, Varlamov V, Vyalikh D, Kummer K, Sivkov VV, Molodtsov SL, Meissner H, Richter G, Hunoldt S, Kammer M, Paasch S, Krasokhin V, Patzke G, Brunner E, Richter W In order to evaluate the biomedical potential of three-dimensional chitinous scaffolds of poriferan origin, chondrocyte culturing experiments were performed. It was shown for the first time that freshly isolated chondrocytes attached well to the chitin scaffold and synthesized an extracellular matrix similar to that found in other cartilage tissue engineering constructs. Chitin scaffolds also supported deposition of a proteoglycan-rich extracellular matrix of chondrocytes seeded bioconstructs in an in vivo environment. We suggest that chitin sponge scaffolds, apart from the demonstrated biomedical applications, are highly optimized structures for use as filtering systems, templates for biomineralization as well as metallization in order to produce catalysts. PMID: 20478334 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Tissue Engineering of Cartilage Replacement Material - Mechanical Stimulation in the in-vitro Cultivation of Human Chondrocytes. Z Orthop Unfall. 2010 Oct 12; Authors: Nebelung S, Ladenburger A, Gavenis K, Stoffel M, Andereya S, Müller-Rath R The treatment of cartilage defects remains a major problem in orthopaedics. With regard to cartilage tissue engineering, the reimplantation of pre-cultivated chondrocytes in the form of a chondrocyte graft is a promising alternative to conventional methods. Clinical practice requires this MACT procedure (matrix-associated autologous chondrocyte transplantation) to produce a biocompatible replacement tissue with adequate mechanical properties. Mechanical stimulation has the capacity to improve the quality of these cell-seeded biomaterials. By altering chondrocytes' cellular activities, the biological and biomechanical properties of cartilage replacement tissue can be modulated. Different systems are used for this purpose, e.g. shear, perfusion, hydrostatic pressure or compression. The mechanisms, biological effects, chances and problems of the techniques are presented and assessed. Among the stimulating techniques considered are systems that apply indirect and direct shear forces such as spinner flasks, rotating-wall bioreactors, direct tissue shear and perfusion culture systems. The application of hydrostatic pressure or compression may be brought about by either static or dynamic loading systems. Compressive loading is considered in the light of both its short- and long-term effects; additionally two exemplified systems are discussed in detail. However, despite promising approaches and seemingly favourable tissue characteristics, the in vitro culturing of functional cartilage replacement tissue with cartilage-like mechanical and biological characteristics still remains elusive. Furthermore, controlling, monitoring and regulating culturing conditions are general biotechnological requirements of a standardised in vitro cultivation. Among these, different aspects such as aseptic operation, media supplementation, nutrient and gas exchange, temperature and humidity control are considered. PMID: 20941688 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | How do biomaterials affect the biological activities and responses of cells? An in vitro study. Minerva Stomatol. 2010 Sep;59(9):445-64 Authors: Pappalardo S, Carlino V, Brutto D, Sinatra F AIM: As part of regenerative bone surgery, according to the principles of tissue engineering and GBR, the use of biomaterials aims to restore bone deficiencies by restoring both functionality and original morphology of the bone tissue. Besides being biocompatible, biofunctional and reabsorbable, the ideal scaffolding should possess an osteoinductive geometry, which depends on many physical-chemical characteristics and, in particular, on a three-dimensional morphology and the placement of molecules, which would determine pore size and interconnection between them. The purpose of this study was, therefore, to carry out an analysis with a scanning electron microscope, in order to evaluate the effect of the diameter size of the scaffold pores on the bio-molecular interaction between osteoblast-like MG63 cells and four biomaterials with different pore sizes: polylactic-co-glycolic acid, deproteinized bovine bone, equine bone, demineralized bone matrix (DBM). METHODS: Through the observations made with SEM and X-ray microanalysis, it is possible to infer how the morphology, the proliferative ability, the modality of adhesion and the differentiation of MG63 cells are influenced in different ways by the porous structure of the various biomaterials used as a substrate for growth. RESULTS: From among all of the biomaterials examined, DBM represented the best substrate for growth; in fact, there would be a more intense and precocious adhesion of MG-63 cells. CONCLUSION: The strong osteoconductive effect observed in human DBM, seems to be related to the presence of the organic component, while the osteoinductive effect would be mainly attributed to the presence of BMPs. PMID: 20940685 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Biomimetic Analogs for Collagen Biomineralization. J Dent Res. 2010 Oct 12; Authors: Gu L, Kim YK, Liu Y, Ryou H, Wimmer CE, Dai L, Arola DD, Looney SW, Pashley DH, Tay FR Inability of chemical phosphorylation of sodium trimetaphosphate to induce intrafibrillar mineralization of type I collagen may be due to the failure to incorporate a biomimetic analog to stabilize amorphous calcium phosphates (ACP) as nanoprecursors. This study investigated adsorption/desorption characteristics of hydrolyzed and pH-adjusted sodium trimetaphosphate (HPA-Na(3)P(3)O(9)) to collagen. Based on those results, a 5-minute treatment time with 2.8 wt% HPA-Na(3)P(3)O(9) was used in a single-layer reconstituted collagen model to confirm that both the ACP-stabilization analog and matrix phosphoprotein analog must be present for intrafibrillar mineralization. The results of that model were further validated by complete remineralization of phosphoric-acid-etched dentin treated with the matrix phosphoprotein analog and lined with a remineralizing lining composite, and with the ACP-stabilization analog supplied in simulated body fluid. An understanding of the basic processes involved in intrafibrillar mineralization of reconstituted collagen fibrils facilitates the design of novel tissue engineering materials for hard tissue repair and regeneration. PMID: 20940362 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Hunter-Schreger Band patterns and their implications for clinical dentistry. J Oral Rehabil. 2010 Oct 6; Authors: Lynch CD, O'Sullivan VR, Dockery P, McGillycuddy CT, Rees JS, Sloan AJ Summary Hunter-Schreger Bands (HSBs) are an optical phenomenon visualised when a cut or fractured enamel surface is viewed under reflected light. These bands demonstrate the synchronous decussation of individual or groups of enamel prisms. While the role of HSB patterns has been investigated in comparative anatomical studies, until recently there has been little consideration of HSB patterns in human teeth. The aim of this paper is to consider the significance of HSB patterns in the human dentition and in relation to clinical dentistry. It is concluded that within the human dentition, HSB patterns have evolved to optimise resistance to attrition, abrasion and tooth fracture. It appears that certain aspects of HSB packing densities and distributions have beneficial roles in enamel bonding. Hunter-Schreger Band patterns seem to passively facilitate conditions such as abfraction and cracked tooth syndrome. PMID: 20939845 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Scaffold Vascularization: A Challenge for Three-Dimensional Tissue Engineering. Curr Med Chem. 2010 Oct 13; Authors: Bramfeldt H, Sabra G, Centis V, Vermette P The prevalent challenge facing tissue engineering today is the lack of adequate vascularization to support the growth, function, and viability of tissue substitutes that require blood vessel supply. Researchers rely on the increasing knowledge of angiogenic and vasculogenic processes to stimulate vascular network formation within three-dimensional tissue constructs. These processes are mainly endothelial cell-regulated, although in the context of tissue engineering, specific interactions with scaffold materials, growth factors and other cell types may require in vitro vascularization schemes to be altered accordingly. To better mimic the complete in vivo environment, increasing attention is given to the integration of co-cultures and mechanical conditioning in bioreactors. Such approaches show great promise for the enhancement of the functionality and clinical applicability of tissue engineering constructs. This paper reviews some scaffold materials used in tissue engineering and the effect of their properties on the vascularization process. Also, it specifically addresses the pivotal role of biomaterials vascularization in tissue engineering applications, along with the effect of angiogenic factors and adhesive molecules on angiogenesis. Assays and markers of angiogenesis are also outlined. One section highlights the need for bioreactor cultures and mechanical conditioning in controlling endothelial cell responses. Finally, we conclude with a brief section on the effects of oxygen concentration and hypoxia over microvessel formation. PMID: 20939827 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Research progress of electrospun nanofibers scaffold in nerve tissue engineering] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2010 Sep;24(9):1133-7 Authors: Hu X, Wang G OBJECTIVE: To review the research progress of electrospun nanofibers scaffold in nerve tissue engineering. METHODS: The related literature on electrospun nanofibers scaffold in nerve tissue engineering was extensively reviewed and analyzed. RESULTS: A variety of material nanofibers scaffolds can be fabricated through electrospinning. The chemical and physical properties of the scaffold can be modified and it was suitable for neuron. The scaffold can bridge the defect of peripheral nerve and partial function an partin be restored. CONCLUSION: Electrospun nanofibers scaffold has broad application prospects in nerve tissue engineering. PMID: 20939490 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | [Extraction techniques and biocompatibility evaluations of naturally derived nerve extracellular matrix] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2010 Sep;24(9):1128-32 Authors: Wang Y, Peng J, Zhao Z, Huang J, Zhao B, Zhang L, Sui X, Xu W, Chen J, Lu S OBJECTIVE: Native extracellular matrix (ECM) is comprised of a complex network of structural and regulatory proteins that are arrayed into a tissue-specific, biomechanically optimal, fibrous matrix. The multifunctional nature of the native ECM will need to be considered in the design and fabrication of tissue engineering scaffolds. To investigate the extraction techniques of naturally derived nerve ECM and the feasibility of nerve tissue engineering scaffold. METHODS: Ten fresh canine sciatic nerves were harvested; nerve ECM material was prepared by hypotonic freeze-thawing, mechanical grinding, and differential centrifugation. The ECM was observed by scanning electron microscope. Immunofluorescence staining was performed to detect specific ECM proteins including collagen type I, laminin, and fibronectin. Total collagen and glycosaminoglycan (GAG) contents were assessed using biochemical assays. The degree of decellularization was evaluated with staining for nuclei using Hoechst33258. The dorsal root ganglion and Schwann cells of rats were respectively seeded onto nerve tissue-specific ECM films. The biocompatibility was observed by specific antibodies for cell markers. RESULTS: Scanning electron microscope analysis revealed that nerve-derived ECM consisted of a nanofibrous structure, which diameter was 30-130 nm. Immunofluorescence staining confirmed that the nerve-derived ECM was made up of collagen type I, laminin, and fibronectin. The histological staining showed that the staining results of sirius red, Safranin O, and toluidine blue were positive. Hoechst33258 staining showed no DNA within the decellularized ECM. Those ECM films had good biocompatibility for dorsal root ganglion and Schwann cells. The cotents of total collagen and GAG in the nerve-derived ECM were (114.88 +/- 13.33) microg/mg and (17.52 +/- 2.34) microg/mg, showing significant difference in the content of total collagen (P < 0.01) and no significant difference in the content of GAG (P > 0.05) when compared with the contents of normal nerve tissue [(54.07 +/- 5.06) microg/mg and (25.25 +/- 1.56) microg/mg)]. The results of immunofluorescence staining were positive for neurofilament 200 after 7 days and for S100 after 2 days. CONCLUSION: Nerve-derived ECM is rich in collagen type I, laminin, and fibronectin and has good biocompatibility, so it can be used as a nerve tissue engineering scaffold. PMID: 20939489 [PubMed - in process] | | | | | | | | | |  | |  | |  |
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