| Please add updates@feedmyinbox.com to your address book to make sure you receive these messages in the future. | |
| CIRM Staff Cap/Reform Legislation Hanging Fire
May 14, 2010 at 9:40 AM
|
| With less than two weeks remaining before a key deadline, directors of the California stem cell agency have cancelled a meeting on legislation to remove the 50-person cap on its staff, and no additional sessions have yet been scheduled.
In response to a query, CIRM Vice Chairman Art Torres told the California
Stem Cell Report that a final agreement had not yet been reached on the terms of the | | |
| Microporation is a valuable transfection method for efficient gene delivery into human umbilical cord blood-derived mesenchymal stem cells.
May 14, 2010 at 8:06 AM
|
| | Microporation is a valuable transfection method for efficient gene delivery into human umbilical cord blood-derived mesenchymal stem cells. BMC Biotechnol. 2010 May 13;10(1):38 Authors: Lim JY, Park SH, Jeong CH, Oh JH, Kim SM, Ryu CH, Park SA, Ahn JG, Oh W, Jeun SS, Chang JW ABSTRACT: BACKGROUND: Mesenchymal stem cells (MSCs) are an attractive source of adult stem cells for therapeutic application in clinical study. Genetic modification of MSCs with beneficial genes makes them more effective for therapeutic use. However, it is difficult to transduce genes into MSCs by common transfection methods, especially nonviral methods. In this study, we applied microporation technology as a novel electroporation technique to introduce enhanced green fluorescent protein (EGFP) and brain-derived neurotropfic factor (BDNF) plasmid DNA into human umbilical cord blood-derived MSCs (hUCB-MSCs) with significant efficiency, and investigated the stem cell potentiality of engineered MSCs through their phenotypes, proliferative capacity, ability to differentiate into multiple lineages, and migration ability towards malignant glioma cells. RESULTS: Using microporation with EGFP as a reporter gene, hUCB-MSCs were transfected with higher efficiency (83%) and ! only minimal cell damage than when conventional liposome-based reagent (<20%) or established electroporation methods were used (30-40%). More importantly, microporation did not affect the immunophenotype of hUCB-MSCs, their proliferation activity, ability to differentiate into mesodermal and ectodermal lineages, or migration ability towards cancer cells. In addition, the BDNF gene could be successfully transfected into hUCB-MSCs, and BDNF expression remained fairly constant for the first 2 weeks in vitro and in vivo. Moreover, microporation of BDNF gene into hUCB-MSCs promoted their in vitro differentiation into neural cells. CONCLUSION: Taken together, the present data demonstrates the value of microporation as an efficient means of transfection of MSCs without changing their multiple properties. Gene delivery by microporation may enhance the feasibility of transgenic stem cell therapy. PMID: 20462460 [PubMed - as supplied by publisher] | | |
| [Salivary gland stem cells : Can they restore radiation-induced salivary gland dysfunction?]
May 14, 2010 at 6:29 AM
|
| | [Salivary gland stem cells : Can they restore radiation-induced salivary gland dysfunction?] HNO. 2010 May 13; Authors: Rotter N, Schwarz S, Jakob M, Brandau S, Wollenberg B, Lang S Adult stem cells are actively investigated in the fields of regenerative medicine and tissue engineering, as they exhibit specific characteristics that make them promising candidates for cellular therapies. Depending on their tissue of origin these characteristics include long-term proliferation and the capacity to differentiate into various cell types. To date adult stem cells have been isolated from a multitude of tissues. Non-embryogenic adult tissues contain only small numbers of such stem cells and the derivation of such tissues can cause comorbidities. Therefore, there is ongoing interest in the identification and characterisation of novel cell sources for stem cell isolation and characterisation.Recently, salivary gland tissue has also been explored as a possible source of stem cells, first in animals and later in humans. Such salivary gland-derived stem cells might be useful in the treatment of radiation-induced salivary gland hypofunction, and possibly al! so in other diseases with loss of acinar cells, such as sequelae of radio iodine treatment or Sjögren's disease.In this paper we review the current status of salivary gland stem cell biology and application and discuss the possible role of stem cells in the development of novel therapies for salivary gland dysfunctions such as postradiogenic xerostomia. PMID: 20464362 [PubMed - as supplied by publisher] | | |
| Thyroid stem cells--danger or resource?
May 14, 2010 at 6:29 AM
|
| | Thyroid stem cells--danger or resource? Acta Otorhinolaryngol Ital. 2009 Dec;29(6):290-5 Authors: Gibelli B, El-Fattah A, Giugliano G, Proh M, Grosso E The thyroid gland has long since been known for its self-renewal ability, mainly in cases of hyperplastic disease such as goitre. Recently the amazing improvement in knowledge about stem cells has explained this potentiality. Some stem cell features and their clinical usefulness are summarized here, reviewing data from the literature: (1) the proven presence of adult stem cells in thyroid tissue, either normal, goitrous or neoplastic, bring with it important implications regarding tissue regeneration and oncogenesis; (2) modifying culture conditions and micro-environment stem cells have led to mature tissue with specialized functions. This has considerably changed the attitude of regenerative medicine and cancer research; (3) finally, identification of stem cells and stem cell markers in thyroid cancer, gives hope for the development of new therapeutic approaches in recurrent or treatment-resistant thyroid cancer. PMID: 20463832 [PubMed - in process] | | |
| Modulation of embryonic stem cell fate and somatic cell reprogramming by small molecules.
May 14, 2010 at 6:29 AM
|
| | Modulation of embryonic stem cell fate and somatic cell reprogramming by small molecules. Reprod Biomed Online. 2010 Mar 29; Authors: Zhang XZ Embryonic stem cells (ESC) are pluripotent cells and have the ability to self-renew in vitro and to differentiate into cells representing all three germ layers. They provide enormous opportunities for basic research, regenerative medicine as well as drug discovery. The mechanisms that govern ESC fate are not completely understood, so a better understanding and control of ESC self-renewal and differentiation are pivotal for therapeutic applications. In contrast to growth factors and genetic manipulations, small molecules offer great advantages in modulating ESC fate. For instance, they could be conveniently identified through high-throughput screening, work across multiple signalling pathways and affect epigenetic modifications as well. This review focuses on the recent progress in the use of small molecules to regulate ESC self-renewal, differentiation and somatic cell reprogramming. PMID: 20462797 [PubMed - as supplied by publisher] | | |
| The implications of "advanced therapies" regulation.
May 14, 2010 at 6:29 AM
|
| | The implications of "advanced therapies" regulation. Rejuvenation Res. 2010 Apr-Jun;13(2-3):327-8 Authors: Sethe SC Recent policy developments in the United States and Europe have created new regulatory regimes for advanced and complex treatments such as cell therapies, tissue engineering, and gene therapies that are of particular relevance for regenerative medicine. Where these new legal rules operate as a mere extension of existing regimes, they risk stifling innovation in these areas of life extension technology. PMID: 20462386 [PubMed - in process] | | |
| Peptide-Modified "Smart" Hydrogels and Genetically Engineered Stem Cells for Skeletal Tissue Engineering.
May 14, 2010 at 6:29 AM
|
| | Peptide-Modified "Smart" Hydrogels and Genetically Engineered Stem Cells for Skeletal Tissue Engineering. Biomacromolecules. 2010 May 12; Authors: Garty S, Kimelman-Bleich N, Hayouka Z, Cohn D, Friedler A, Pelled G, Gazit D Stimuli responsive or "smart" hydrogels are of interest for tissue-engineering applications, featuring the advantages of minimally invasive application. Currently, these materials have yet to be used as a biological replacement in restoring the function of damaged tissues or organs. The aim of this study was to demonstrate the advantages of thermoresponsive, peptide-containing hydrogels as a supportive matrix for genetically engineered stem cells. We used injectable hydrogels, enabling cell delivery to the desired site and providing adequate scaffolding postimplantation. Thermoresponsive hydrogels were developed based on amphiphilic block copolymers of polyethylene-oxide and polypropylene-oxide end-capped with methacrylate or maleimide entities and further reacted with RGD-containing peptides. Cell metabolic activity and survival within those hydrogels was studied, illustrating that the stable peptide-polymer conjugate is required for prolonged cell support. The u! nique polymer characteristics, combined with its enhanced cell interactions, suggest the potential use of these biomaterials in various tissue engineering applications. PMID: 20462241 [PubMed - as supplied by publisher] | | |
| Spirulina promotes stem cell genesis and protects against LPS induced declines in neural stem cell proliferation.
May 14, 2010 at 6:22 AM
|
| | Spirulina promotes stem cell genesis and protects against LPS induced declines in neural stem cell proliferation. PLoS One. 2010;5(5):e10496 Authors: Bachstetter AD, Jernberg J, Schlunk A, Vila JL, Hudson C, Cole MJ, Shytle RD, Tan J, Sanberg PR, Sanberg CD, Borlongan C, Kaneko Y, Tajiri N, Gemma C, Bickford PC Adult stem cells are present in many tissues including, skin, muscle, adipose, bone marrow, and in the brain. Neuroinflammation has been shown to be a potent negative regulator of stem cell and progenitor cell proliferation in the neurogenic regions of the brain. Recently we demonstrated that decreasing a key neuroinflammatory cytokine IL-1beta in the hippocampus of aged rats reversed the age-related cognitive decline and increased neurogenesis in the age rats. We also have found that nutraceuticals have the potential to reduce neuroinflammation, and decrease oxidative stress. The objectives of this study were to determine if spirulina could protect the proliferative potential of hippocampal neural progenitor cells from an acute systemic inflammatory insult of lipopolysaccharide (LPS). To this end, young rats were fed for 30 days a control diet or a diet supplemented with 0.1% spirulina. On day 28 the rats were given a single i.p. injection of LPS (1 mg/kg). The f! ollowing day the rats were injected with BrdU (50 mg/kg b.i.d. i.p.) and were sacrificed 24 hours after the first injection of BrdU. Quantification of the BrdU positive cells in the subgranular zone of the dentate gyrus demonstrated a decrease in proliferation of the stem/progenitor cells in the hippocampus as a result of the LPS insult. Furthermore, the diet supplemented with spirulina was able to negate the LPS induced decrease in stem/progenitor cell proliferation. In a second set of studies we examined the effects of spirulina either alone or in combination with a proprietary formulation (NT-020) of blueberry, green tea, vitamin D3 and carnosine on the function of bone marrow and CD34+ cells in vitro. Spirulina had small effects on its own and more than additive effects in combination with NT-020 to promote mitochondrial respiration and/or proliferation of these cells in culture. When examined on neural stem cells in culture spirulina increased proliferation at baseline! and protected against the negative influence of TNFalpha to r! educe ne ural stem cell proliferation. These results support the hypothesis that a diet enriched with spirulina and other nutraceuticals may help protect the stem/progenitor cells from insults. PMID: 20463965 [PubMed - in process] | | |
| REX-1 expression and p38 MAPK activation status can determine proliferation/differentiation fates in human mesenchymal stem cells.
May 14, 2010 at 6:22 AM
|
| | REX-1 expression and p38 MAPK activation status can determine proliferation/differentiation fates in human mesenchymal stem cells. PLoS One. 2010;5(5):e10493 Authors: Bhandari DR, Seo KW, Roh KH, Jung JW, Kang SK, Kang KS BACKGROUND: REX1/ZFP42 is a well-known embryonic stem cell (ESC) marker. However, the role of REX1, itself, is relatively unknown because the function of REX1 has only been reported in the differentiation of ESCs via STAT signaling pathways. Human mesenchymal stem cells (hMSCs) isolated from young tissues and cancer cells express REX1. METHODOLOGY/PRINCIPAL FINDING: Human umbilical cord blood-derived MSCs (hUCB-MSCs) and adipose tissue-derived MSCs (hAD-MSCs) strongly express REX1 and have a lower activation status of p38 MAPK, but bone marrow-derived MSCs (hBM-MSCs) have weak REX1 expression and higher activation of p38 MAPK. These results indicated that REX1 expression in hMSCs was positively correlated with proliferation rates but inversely correlated with the phosphorylation of p38 MAPK. In hUCB-MSCs, the roles of REX1 and p38 MAPK were investigated, and a knockdown study was performed using a lentiviral vector-based small hairpin RNA (shRNA). After REX1 knock! down, decreased cell proliferation was observed. In REX1 knocked-down hUCB-MSCs, the osteogenic differentiation ability deteriorated, but the adipogenic potential increased or was similar to that observed in the controls. The phosphorylation of p38 MAPK in hUCB-MSCs significantly increased after REX1 knockdown. After p38 MAPK inhibitor treatment, the cell growth in REX1 knocked-down hUCB-MSCs almost recovered, and the suppressed expression levels of CDK2 and CCND1 were also restored. The expression of MKK3, an upstream regulator of p38 MAPK, significantly increased in REX1 knocked-down hUCB-MSCs. The direct binding of REX1 to the MKK3 gene was confirmed by a chromatin immunoprecipitation (ChIP) assay. CONCLUSIONS/SIGNIFICANCE: These findings showed that REX1 regulates the proliferation/differentiation of hMSCs through the suppression of p38 MAPK signaling via the direct suppression of MKK3. Therefore, p38 MAPK and REX-1 status can determine the cell fate of adult stem cells! (ASCs). These results were the first to show the role of REX1! in the proliferation/differentiation of ASCs. PMID: 20463961 [PubMed - in process] | | |
| [Salivary gland stem cells : Can they restore radiation-induced salivary gland dysfunction?]
May 14, 2010 at 6:17 AM
|
| | [Salivary gland stem cells : Can they restore radiation-induced salivary gland dysfunction?] HNO. 2010 May 13; Authors: Rotter N, Schwarz S, Jakob M, Brandau S, Wollenberg B, Lang S Adult stem cells are actively investigated in the fields of regenerative medicine and tissue engineering, as they exhibit specific characteristics that make them promising candidates for cellular therapies. Depending on their tissue of origin these characteristics include long-term proliferation and the capacity to differentiate into various cell types. To date adult stem cells have been isolated from a multitude of tissues. Non-embryogenic adult tissues contain only small numbers of such stem cells and the derivation of such tissues can cause comorbidities. Therefore, there is ongoing interest in the identification and characterisation of novel cell sources for stem cell isolation and characterisation.Recently, salivary gland tissue has also been explored as a possible source of stem cells, first in animals and later in humans. Such salivary gland-derived stem cells might be useful in the treatment of radiation-induced salivary gland hypofunction, and possibly al! so in other diseases with loss of acinar cells, such as sequelae of radio iodine treatment or Sjögren's disease.In this paper we review the current status of salivary gland stem cell biology and application and discuss the possible role of stem cells in the development of novel therapies for salivary gland dysfunctions such as postradiogenic xerostomia. PMID: 20464362 [PubMed - as supplied by publisher] | | |
| Electrochemical growth behavior, surface properties, and enhanced in vivo bone response of TiO2 nanotubes on microstructured surfaces of blasted, screw-shaped titanium implants.
May 14, 2010 at 6:17 AM
|
| | Electrochemical growth behavior, surface properties, and enhanced in vivo bone response of TiO2 nanotubes on microstructured surfaces of blasted, screw-shaped titanium implants. Int J Nanomedicine. 2010;5:87-100 Authors: Sul YT TiO(2) nanotubes are fabricated on TiO(2) grit-blasted, screw-shaped rough titanium (ASTM grade 4) implants (3.75 x 7 mm) using potentiostatic anodization at 20 V in 1 M H(3)PO(4) + 0.4 wt.% HF. The growth behavior and surface properties of the nanotubes are investigated as a function of the reaction time. The results show that vertically aligned nanotubes of approximately 700 nm in length, with highly ordered structures of approximately 40 nm spacing and approximately 15 nm wall thickness may be grown independent of reaction time. The geometrical properties of nanotubes increase with reaction time (mean pore size, pore size distribution [PSD], and porosity approximately 90 nm, approximately 40-127 nm and 45%, respectively for 30 minutes; approximately 107 nm, approximately 63-140 nm and 56% for one hour; approximately 108 nm, approximately 58-150 nm and 60% for three hours). It is found that the fluorinated chemistry of the nanotubes of F-TiO(2), TiOF(2), and F-T! i-O with F ion incorporation of approximately 5 at.%, and their amorphous structure is the same regardless of the reaction time, while the average roughness (Sa) gradually decreases and the developed surface area (Sdr) slightly increases with reaction time. The results of studies on animals show that, despite their low roughness values, after six weeks the fluorinated TiO(2) nanotube implants in rabbit femurs demonstrate significantly increased osseointegration strengths (41 vs 29 Ncm; P = 0.008) and new bone formation (57.5% vs 65.5%; P = 0.008) (n = 8), and reveal more frequently direct bone/cell contact at the bone-implant interface by high-resolution scanning electron microscope observations as compared with the blasted, moderately rough implants that have hitherto been widely used for clinically favorable performance. The results of the animal studies constitute significant evidence that the presence of the nanotubes and the resulting fluorinated surface chemistry dete! rmine the nature of the bone responses to the implants. The pr! esent in vivo results point to potential applications of the TiO(2) nanotubes in the field of bone implants and bone tissue engineering. PMID: 20463928 [PubMed - in process] | | |
| The implications of "advanced therapies" regulation.
May 14, 2010 at 6:17 AM
|
| | The implications of "advanced therapies" regulation. Rejuvenation Res. 2010 Apr-Jun;13(2-3):327-8 Authors: Sethe SC Recent policy developments in the United States and Europe have created new regulatory regimes for advanced and complex treatments such as cell therapies, tissue engineering, and gene therapies that are of particular relevance for regenerative medicine. Where these new legal rules operate as a mere extension of existing regimes, they risk stifling innovation in these areas of life extension technology. PMID: 20462386 [PubMed - in process] | | |
| Peptide-Modified "Smart" Hydrogels and Genetically Engineered Stem Cells for Skeletal Tissue Engineering.
May 14, 2010 at 6:17 AM
|
| | Peptide-Modified "Smart" Hydrogels and Genetically Engineered Stem Cells for Skeletal Tissue Engineering. Biomacromolecules. 2010 May 12; Authors: Garty S, Kimelman-Bleich N, Hayouka Z, Cohn D, Friedler A, Pelled G, Gazit D Stimuli responsive or "smart" hydrogels are of interest for tissue-engineering applications, featuring the advantages of minimally invasive application. Currently, these materials have yet to be used as a biological replacement in restoring the function of damaged tissues or organs. The aim of this study was to demonstrate the advantages of thermoresponsive, peptide-containing hydrogels as a supportive matrix for genetically engineered stem cells. We used injectable hydrogels, enabling cell delivery to the desired site and providing adequate scaffolding postimplantation. Thermoresponsive hydrogels were developed based on amphiphilic block copolymers of polyethylene-oxide and polypropylene-oxide end-capped with methacrylate or maleimide entities and further reacted with RGD-containing peptides. Cell metabolic activity and survival within those hydrogels was studied, illustrating that the stable peptide-polymer conjugate is required for prolonged cell support. The u! nique polymer characteristics, combined with its enhanced cell interactions, suggest the potential use of these biomaterials in various tissue engineering applications. PMID: 20462241 [PubMed - as supplied by publisher] | | |
| In vitro study in the endothelial cell compatibility and endothelialization of genipin-crosslinked biological tissues for tissue-engineered vascular scaffolds.
May 14, 2010 at 6:17 AM
|
| | In vitro study in the endothelial cell compatibility and endothelialization of genipin-crosslinked biological tissues for tissue-engineered vascular scaffolds. J Mater Sci Mater Med. 2010 Feb;21(2):777-85 Authors: Xi-xun Y, Fei L, Yuan-ting X, Chang-xiu W To overcome the cytotoxicity of the chemical reagents used to fix bioprostheses, genipin, a naturally occurring crosslinking agent, was used to fix biological tissues in present study. We prepared the biological vascular scaffolds through cell extraction and fixing the porcine thoracic arteries with 1% (by w/v) genipin solution for 3 days, and then examined their mechanical properties and microstructures; glutaraldehyde- and epoxy-fixed counterparts were used as controls. HUVECs were seeded on the type I collagen-coated surface of different modified acellular vascular tissues (fixed with different crosslinking agents), and the growths of HUVECs on the specimens were demonstrated by means of MTT test, the secretion of PGI2 and vWF by HUVECs on the various specimens was also measured. Finally, HUVECs were seeded on the luminal surface of acellular biological vascular scaffolds (<6 mm internal diameter) which were, respectively, treated in the same manner describe! d above, and then cultured for 9 days. On the ninth day, the HUVECs on the luminal surface of these vascular scaffolds were examined morphologically and by immunohistochemistry. Genipin-fixation can markedly diminish antigenicity of the vascular tissues through partially getting rid of cell or reducing the level of free amino groups in the vascular tissues. Genipin-fixed acellular vascular tissues mimicked the natural vessels due to the maintenance of the integrity of total structure and the large preservation of the microstructures of collagen fibers and elastic fibers; therefore, it appeared suitable to fabricate vascular scaffolds in mechanical properties. Compared to controls, the genipin-fixed acellular vascular tissues were characterized by low cytotoxicity and good cytocompatibility. The HUVECs can not only proliferate well on the genipin-fixed acellular vascular tissues, but also preserve the activities and function of endothelial cells, and easily make it endotheli! alized in vitro. The results showed that the genipin-fixed ace! llular p orcine vascular scaffolds should be promising materials for fabricating vascular grafts or the scaffolds of tissue-engineered blood vessels. PMID: 19915961 [PubMed - indexed for MEDLINE] | | |
| Two ply tubular scaffolds comprised of proteins/poliglecaprone/polycaprolactone fibers.
May 14, 2010 at 6:17 AM
|
| | Two ply tubular scaffolds comprised of proteins/poliglecaprone/polycaprolactone fibers. J Mater Sci Mater Med. 2010 Feb;21(2):541-9 Authors: Zhang X, Thomas V, Vohra YK Electrospun bi-layer tubular hybrid scaffolds composed of poliglecaprone (PGC), polycaprolactone (PCL), elastin (E), and gelatin (G) were prepared and thereafter crosslinked by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). Scanning electron microscopic (SEM) images revealed a highly porous micro-structure comprising randomly distributed non-woven fibers with the majority of fibers in submicron diameters. The EDC-crosslinking yielded an average crosslinking degree of 40%. Uni-axial tensile test of hydrated scaffolds in both longitudinal and circumferential directions revealed tensile properties, comparable to those of native arteries. The graft (PGC:PCL = 1:3) did not demonstrate significant difference before and after EDC-crosslinking in tensile strength or % strain in either longitudinal or circumferential directions. However, crosslinking increased the Young's modulus of the graft along the longitudinal direction (from 5.84 to 8.67 MPa). On! the contrary, the graft (3:1) demonstrated a significant decrease in maximum strain in both directions. Cyto-assay using human umbilical vein endothelial cells (HUVECs) showed excellent cell viability. PMID: 19902335 [PubMed - indexed for MEDLINE] | | |
| Physico-chemical and in vitro biological evaluation of strontium/calcium silicophosphate glass.
May 14, 2010 at 6:17 AM
|
| | Physico-chemical and in vitro biological evaluation of strontium/calcium silicophosphate glass. J Mater Sci Mater Med. 2010 Feb;21(2):695-705 Authors: Hesaraki S, Alizadeh M, Nazarian H, Sharifi D Strontium is known to reduce bone resorption and stimulate bone formation. Incorporation of strontium into calcium phosphate bioceramics has been widely reported. In this work, calcium and calcium/strontium silicophosphate glasses were synthesized from the sol-gel process and their rheological, thermal, and in vitro biological properties were studied and compared to each other. The results showed that the gel viscosity and thus the rate of gel formation increased by using strontium in glass composition and by increasing aging temperature. In strontium-containing glass, the crystallization temperature increased and the type of the crystallized phase was different to that of strontium-free glass. Both glasses favored precipitation of calcium phosphate layer when they were soaked in simulated body fluid; however strontium seemed to retard the rate of precipitation slightly. The in vitro biodegradation rate of the strontium/calcium silicophosphate glass was higher tha! n that of strontium-free one. The cell culture experiments carried out using rat calvaria osteoblasts showed that the incorporation of strontium into the glass composition stimulated proliferation of the cells and enhanced their alkaline phosphatase activity, depending on cell culture period. PMID: 19866346 [PubMed - indexed for MEDLINE] | | |
| In vitro bioactivity of sol-gel-derived hydroxyapatite particulate nanofiber modified titanium.
May 14, 2010 at 6:17 AM
|
| | In vitro bioactivity of sol-gel-derived hydroxyapatite particulate nanofiber modified titanium. J Mater Sci Mater Med. 2010 Feb;21(2):685-94 Authors: Bajgai MP, Parajuli DC, Park SJ, Chu KH, Kang HS, Kim HY A chemically-etched titanium surface was modified by electrospinning a sol-gel-derived hydroxyapatite (HAp) that was subjected to calcination within the temperature range of 200-1400 degrees C in the normative atmospheric condition. After heat treatment, crystal structures of the filmed titanium oxide and HAp on the titanium's surface were identified using wide-angle X-ray diffraction. A highly porous layer of HAp was found to have formed on the oxidized titanium surfaces. The surfaces of three different samples; (1) electrospun HAp, (2) HAp calcined at 600 degrees C, and (3) HAp calcined at 800 degrees C, were investigated for their ability to foster promotion, proliferation, and differentiation of human osteoblasts (HOB) (in the 9th passage) in vitro up to 6 days. Among the three samples, cells cultured on the HAp calcined at 800 degrees C titanium surfaces displayed the best results with regard to adhesion, growth, and proliferation of HOB. This novel method fo! r fabrication of titanium substrates would provide a promising improvement for titanium-based medical devices over the current standards, which lack such substrates. These titanium substrates explicitly provide enhanced HOB proliferation in terms of both desired surface properties and their produced bulk quantity. PMID: 19851842 [PubMed - indexed for MEDLINE] | | |
| A bioactive polymer grafted on titanium oxide layer obtained by electrochemical oxidation. Improvement of cell response.
May 14, 2010 at 6:17 AM
|
| | A bioactive polymer grafted on titanium oxide layer obtained by electrochemical oxidation. Improvement of cell response. J Mater Sci Mater Med. 2010 Feb;21(2):655-63 Authors: Hélary G, Noirclère F, Mayingi J, Bacroix B, Migonney V The anchorage failure of titanium implants in human body is mainly due to biointegration problem. The proposed solution is to graft a bioactive polymer at the surface of the implant in order to improve and control the interactions with the living system. In this paper, we describe the grafting of poly sodium styrene sulfonate on titanium surface by using a silanization reaction. The key point is to increase the TiOH content at the surface of the implant which can react with methoxy silane groups of 3-methacryloxypropyltrimethoxysilane (MPS). Two procedures were used: chemical oxidation and electrochemical oxidation. The last oxidation procedure was carried out in two different electrolytes: oxalic acid and methanol. These different oxidation methods allow controlling the roughness and the depth of the oxide layer. The methacryloyl group of MPS grafted at the titanium surface by silanization reaction is copolymerized with sodium styrene sulfonate using a thermal in! itiator able to produce radicals by heating. Colorimetric method, ATR-FTIR, XPS techniques and contact angle measurements were applied to characterize the surfaces. MG63 osteoblastic cell response was studied on polished, oxidized and grafted titanium samples. Cell adhesion, Alkaline Phosphatase activity and calcium nodules formation were significantly enhanced on grafted titanium surfaces compared to un-modified surfaces. PMID: 19842019 [PubMed - indexed for MEDLINE] | | |
| Osteogenic activity of human periosteal sheets cultured on salmon collagen-coated ePTFE meshes.
May 14, 2010 at 6:17 AM
|
| | Osteogenic activity of human periosteal sheets cultured on salmon collagen-coated ePTFE meshes. J Mater Sci Mater Med. 2010 Feb;21(2):731-9 Authors: Kawase T, Okuda K, Kogami H, Nakayama H, Nagata M, Yoshie H Our animal implantation studies have demonstrated that, after osteogenic processing, cultured human periosteal sheets form osteoid tissue ectopically without the aid of conventional scaffolding materials. To improve the osteogenic activity of these periosteal sheets, we have tested the effects of including a scaffold made of salmon collagen-coated ePTFE mesh. Periosteal sheets were produced with minimal manipulation without enzymatic digestion. Outgrown cells penetrated into the coated mesh fiber networks to form complex multicellular layers and increased expression of alkaline phosphatase activity in response to the osteoinduction. In vitro mineralization was notably enhanced in the original tissue segment regions, but numerous micro-mineral deposits were also formed on the coated-fiber networks. When implanted subcutaneously into nude mice, periosteal sheets efficiently form osteoid around the mineral deposits. These findings suggest that the intricate three-dim! ensional mesh composed of collagen-coated fibers substantially augmented the osteogenic activity of human periosteal sheets both in vitro and in vivo. PMID: 19834787 [PubMed - indexed for MEDLINE] | | |
| Cellular mechanobiology of the intervertebral disc: new directions and approaches.
May 14, 2010 at 6:17 AM
|
| | Cellular mechanobiology of the intervertebral disc: new directions and approaches. J Biomech. 2010 Jan 5;43(1):137-45 Authors: Hsieh AH, Twomey JD The more we learn about the intervertebral disc (IVD), the more we come to appreciate the intricacies involved in transmission of forces through the ECM to the cell, and in the biological determinants of its response to mechanical stress. This review highlights recent developments in our knowledge of IVD physiology and examines their impact on cellular mechanobiology. Discussion centers around the continually evolving cellular and microstructural anatomy of the nucleus pulposus (NP) and the annulus fibrosus (AF) in response to complex stresses generated in support of axial load and spinal motion. Particular attention has been given to cells from the immature NP and the interlamellar AF, and assessment of their potential mechanobiologic contributions to the health and function of the IVD. In addition, several innovative approaches that have been brought to bear on studying the interplay between disc cells and their micromechanical environment are discussed. Techniq! ues for "engineering" cellular function and technologies for fabricating more structurally defined biomaterial scaffolds have recently been employed in disc research. Such tools can be used to elucidate the biological and physical mechanisms by which different IVD cell populations are regulated by mechanical stress, and contribute to advancement of preventative and therapeutic measures. PMID: 19828150 [PubMed - indexed for MEDLINE] | | |
| Mechanics and mechanobiology of mesenchymal stem cell-based engineered cartilage.
May 14, 2010 at 6:17 AM
|
| | Mechanics and mechanobiology of mesenchymal stem cell-based engineered cartilage. J Biomech. 2010 Jan 5;43(1):128-36 Authors: Huang AH, Farrell MJ, Mauck RL In this review, we outline seminal and recent work highlighting the potential of mesenchymal stem cells (MSCs) in producing cartilage-like tissue equivalents. Specific focus is placed on the mechanical properties of engineered MSC-based cartilage and how these properties relate to that of engineered cartilage based on primary chondrocytes and to native tissue properties. We discuss current limitations and/or concerns that must be addressed for the clinical realization of MSC-based cartilage therapeutics, and provide some insight into potential underpinnings for the observed deviations from chondrocyte-based engineered constructs. We posit that these differences reveal specific deficits in terms of our description of chondrogenesis, and suggest that new benchmarks must be developed towards this end. Further, we describe the growing body of literature on the mechanobiology of MSC-based cartilage, highlighting positive findings with regards to the furtherance of the ! chondrogenic phenotype. We likewise discuss the failure of early molecular changes to translate directly into engineered constructs with improved mechanical properties. Finally, we highlight recent work from our group and others that may point to new strategies for enhancing the formation of engineered cartilage based on MSCs. PMID: 19828149 [PubMed - indexed for MEDLINE] | | | | 
| This email was sent to regenmd@gmail.com. Account Login
Don't want to receive this feed any longer? Unsubscribe here
This email was carefully delivered by Feed My Inbox. 230 Franklin Road Suite 814 Franklin, TN 37064 | |
No comments:
Post a Comment