|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Rapid attachment of adipose stromal cells on resorbable polymeric scaffolds facilitates the one-step surgical procedure for cartilage and bone tissue engineering purposes. J Orthop Res. 2011 Jan 18; Authors: Jurgens WJ, Kroeze RJ, Bank RA, Ritt MJ, Helder MN The stromal vascular fraction (SVF) of adipose tissue provides an abundant source of mesenchymal stem cells. For clinical application, it would be beneficial to establish treatments in which SVF is obtained, seeded onto a scaffold, and returned into the patient within a single surgical procedure. In this study, we evaluated the suitability of both a macroporous poly(L-lactide-co-caprolactone) and a porous collagen type I/III scaffold for this purpose. Surprisingly, cell attachment was rapid (∼10 min) and sequestered the majority of adipose stem cells, as deduced from colony-forming unit assays. Proliferation occurred in both polymeric scaffolds. Upon chondrogenic induction, up-regulation of chondrogenic genes, production of glycosaminoglycans, and accumulation of collagen type II was observed, indicating differentiation of scaffold-attached SVF cells along the chondrogenic lineage. Osteogenic differentiation was achieved in both scaffold types, as visualized by up-regulation of osteogenic genes, increase of alkaline phosphatase production over time, and accumulation of bone sialoprotein and osteonectin. In conclusion, this study identifies both poly(L-lactide-co-caprolactone) and collagen type I/III as promising scaffold materials for rapid attachment of adipose stem cell-like (stromal) cells, enhancing the development of one-step surgical concepts for cartilage and bone tissue engineering. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res. PMID: 21246614 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Surface Phosphorylation for Polyelectrolyte Complex of Chitosan and Its Sulfonated Derivative: Surface Analysis, Blood Compatibility and Adipose Derived Stem Cell Contact Properties. J Biomater Sci Polym Ed. 2011 Jan 18; Authors: Yeh HY, Lin JC Many studies have tried to look for the application of chitosan in tissue engineering since its structure is similar to glycoaminoglycans, the main components of the extracellular matrix. Previous studies had indicated that the incorporation of sulfonic or phosphonic functionalities would be beneficial to the growth of certain cells. However, no study has explored the effect of incorporation of both above-mentioned anionic functionalities onto the chitosan structure. In this study, we have surface-phosphorylated the polyelectrolyte film formed by chitosan and water-soluble sulfonated chitosan with the aim to incorporate phosphonic and sulfonic functionalities onto the film surface. Surface analyses by ESCA and ATR-FT-IR have shown that these two functional groups have been successfully grafted onto the surface, and that the ratio of P/S was dependent upon the weight ratio of phosphorylation agents added. Blood compatibility evaluation indicated that phosphorylated polyelectrolyte complexes extended the plasma recalcification time as compared to non-treated chitosan and direct-phosphorylated chitosan film. In addition, these phosphorylated polyelectrolyte complexes showed similar or slightly less platelet reactivity than the non-phosphorylated counterpart. In contrast, significant platelet activation and adhesion were noted on the direct-phosphorylated chitosan. This implicated the incorporation of sulfonic acid onto the phosphorylated surface can increase the platelet compatibility. An adipose-derived stem cell incubation study has demonstrated that the incorporation of both phosphonic and sulfonic acid functionalities onto the chitosan surface can enhance the stem cell growth. Therefore, the phosphorylated polyelectrolyte complexes were not only blood compatible but also stem cell compatible, and could be a novel biomaterial in tissue-engineering applications. PMID: 21244720 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Stem cells from fatty tissue : A new resource for regenerative medicine?]. Chirurg. 2010 Sep;81(9):826-32 Authors: Kuhbier JW, Weyand B, Sorg H, Radtke C, Vogt PM, Reimers K While stem cells derived from the bone marrow are well-known in clinical medicine, fatty tissue as a source of mesenchymal stem cells is still the subject of recent research. However, adipose-derived stem cells (ASC) are not only harvested less invasively, i.e. via minimally invasive liposuction, but also yield higher numbers of multipotent stem cells.Due to cell-cell interactions and also because of the very favorable secretion profile of growth factors and cytokines ASCs displayed an extraordinary regenerative potential in recent preclinical and clinical applications and achieved a significantly better healing in ischemic muscle, heart, and brain insults and in impaired wound healing. ASCs enhanced regeneration in skeletal tissues such as cartilage or bone. They also revealed immunomodulatory effects and improved the clinical status in immunological diseases.In conclusion ASCs are comparable to bone marrow-derived stem cells concerning possible applications in clinical medicine. PMID: 20830547 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Curcumin mediated suppression of nuclear factor-κB promotes chondrogenic differentiation of mesenchymal stem cells in a high-density co-culture microenvironment. Arthritis Res Ther. 2010;12(4):R127 Authors: Buhrmann C, Mobasheri A, Matis U, Shakibaei M INTRODUCTION : Osteoarthritis (OA) and rheumatoid arthritis (RA) are characterised by joint inflammation and cartilage degradation. Although mesenchymal stem cell (MSC)-like progenitors are resident in the superficial zone of articular cartilage, damaged tissue does not possess the capacity for regeneration. The high levels of pro-inflammatory cytokines present in OA/RA joints may impede the chondrogenic differentiation of these progenitors. Interleukin (IL)-1β activates the transcription factor nuclear factor-κB (NF-κB), which in turn activates proteins involved in matrix degradation, inflammation and apoptosis. Curcumin is a phytochemical capable of inhibiting IL-1β-induced activation of NF-κB and expression of apoptotic and pro-inflammatory genes in chondrocytes. Therefore, the aim of the present study was to evaluate the influence of curcumin on IL-1β-induced NF-κB signalling pathway in MSCs during chondrogenic differentiation. METHODS : MSCs were either cultured in a ratio of 1:1 with primary chondrocytes in high-density culture or cultured alone in monolayer with/without curcumin and/or IL-1β. RESULTS : We demonstrate that although curcumin alone does not have chondrogenic effects on MSCs, it inhibits IL-1β-induced activation of NF-κB, activation of caspase-3 and cyclooxygenase-2 in MSCs time and concentration dependently, as it does in chondrocytes. In IL-1β stimulated co-cultures, four-hour pre-treatment with curcumin significantly enhanced the production of collagen type II, cartilage specific proteoglycans (CSPGs), β1-integrin, as well as activating MAPKinase signaling and suppressing caspase-3 and cyclooxygenase-2. CONCLUSIONS : Curcumin treatment may help establish a microenvironment in which the effects of pro-inflammatory cytokines are antagonized, thus facilitating chondrogenesis of MSC-like progenitor cells in vivo. This strategy may support the regeneration of articular cartilage. PMID: 20594343 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Cell polarity and spindle orientation in the distal epithelium of embryonic lung. Dev Dyn. 2011 Feb;240(2):441-5 Authors: El-Hashash AH, Warburton D A proper balance between self-renewal and differentiation of lung-specific progenitors at the distal epithelial tips is absolutely required for normal lung morphogenesis. Cell polarity and mitotic spindle orientation play a critical role in the self-renewal/differentiation of epithelial cells and can impact normal physiological processes, including epithelial tissue branching and differentiation. Therefore, understanding the behavior of lung distal epithelial progenitors could identify innovative solutions to restoring normal lung morphogenesis. Yet little is known about cell polarity, spindle orientation, and segregation of cell fate determinant in the embryonic lung epithelium, which contains progenitor cells. Herein, we provide the first evidence that embryonic lung distal epithelium is polarized and highly mitotic with characteristic perpendicular cell divisions. Consistent with these findings, mInsc, LGN, and NuMA polarity proteins, which control spindle orientation, are asymmetrically localized in mitotic distal epithelial progenitors of embryonic lungs. Furthermore, the cell fate determinant Numb is asymmetrically distributed at the apical side of distal epithelial progenitors and segregated to one daughter cell in most mitotic cells. These findings provide evidence for polarity in distal epithelial progenitors of embryonic lungs and provide a framework for future translationally oriented studies in this area. Developmental Dynamics 240:441-445, 2011. © 2011 Wiley-Liss, Inc. PMID: 21246661 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Characterization of the laminin gene family and evolution in zebrafish. Dev Dyn. 2011 Feb;240(2):422-31 Authors: Sztal T, Berger S, Currie PD, Hall TE Laminins are essential components of all basement membranes and are fundamental to tissue development and homeostasis. Humans possess at least 16 different heterotrimeric laminin complexes formed through different combinations of alpha, beta, and gamma chains. Individual chains appear to exhibit unique expression patterns, leading to the notion that overlap between expression domains governs the constitution of complexes found within particular tissues. However, the spatial and temporal expression of laminin genes has not been comprehensively analyzed in any vertebrate model to date. Here, we describe the tissue-specific expression patterns of all laminin genes in the zebrafish, throughout embryonic development and into the "post-juvenile" period, which is representative of the adult body form. In addition, we present phylogenetic and microsynteny analyses, which demonstrate that the majority of our zebrafish sequences are orthologous to human laminin genes. Together, these data represent a fundamental resource for the study of vertebrate laminins. Developmental Dynamics 240:422-431, 2011. © 2011 Wiley-Liss, Inc. PMID: 21246659 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | An antiaging and regenerative medicine approach to optimal skin health. Facial Plast Surg. 2011 Feb;27(1):29-34 Authors: Pontius AT, Smith PW The optimal health and appearance of the skin is the result of several factors: extrinsic aging (UV damage), intrinsic aging (genetics, lifestyle), and hormonal aging (primarily estrogen loss). This article intends to take an antiaging and regenerative medicine approach to the aging skin and focus on both the hormonal causes and the intrinsic causes of aging; namely, hormones, diet, and lifestyle. By taking a functional approach to the evaluation and treatment of the skin, we hope to elucidate the causation of the condition of the skin and provide targeted treatments to improve its quality. We will sequentially cover the topics of hormonal decline and the skin, understanding hormone replacement, aging and the skin, and key nutrients for youthful skin. We hope to provide a more comprehensive approach to treating the aging face and skin that will provide patients with more long-lasting and youthful results. PMID: 21246454 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Pluripotency factors regulate definitive endoderm specification through eomesodermin. Genes Dev. 2011 Jan 18; Authors: Teo AK, Arnold SJ, Trotter MW, Brown S, Ang LT, Chng Z, Robertson EJ, Dunn NR, Vallier L Understanding the molecular mechanisms controlling early cell fate decisions in mammals is a major objective toward the development of robust methods for the differentiation of human pluripotent stem cells into clinically relevant cell types. Here, we used human embryonic stem cells and mouse epiblast stem cells to study specification of definitive endoderm in vitro. Using a combination of whole-genome expression and chromatin immunoprecipitation (ChIP) deep sequencing (ChIP-seq) analyses, we established an hierarchy of transcription factors regulating endoderm specification. Importantly, the pluripotency factors NANOG, OCT4, and SOX2 have an essential function in this network by actively directing differentiation. Indeed, these transcription factors control the expression of EOMESODERMIN (EOMES), which marks the onset of endoderm specification. In turn, EOMES interacts with SMAD2/3 to initiate the transcriptional network governing endoderm formation. Together, these results provide for the first time a comprehensive molecular model connecting the transition from pluripotency to endoderm specification during mammalian development. PMID: 21245162 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The Pro-Inflammatory Role of Adiponectin at the Maternal-Fetal Interface. Am J Reprod Immunol. 2011 Jan 19; Authors: McDonald EA, Wolfe MW Citation McDonald EA, Wolfe MW. The pro-inflammatory role of adiponectin at the maternal-fetal interface. Am J Reprod Immunol 2011 Problem A successful pregnancy is contingent on maternal tolerance of the immunologically foreign fetus. Prevalent diseases such as preeclampsia arise in part due to an inappropriate immune response by the placenta. A number of molecules have been proposed to temper cellular response to pro-inflammatory mediators, including CD24 and Siglec10. Methods Cytotrophoblast cells from healthy term placentas were treated with adiponectin in vitro and analyzed with qPCR and ELISA-based assays. Immunohistochemistry was performed on term villous sections and cultured trophoblasts. Results Treatment with adiponectin increased expression of IL-1β and IL-8. Term villi express CD24 in cytotrophoblasts and the syncytiotrophoblast, and Siglec10 by the syncytiotrophoblast. Treatment of trophoblast cells with adiponectin increased Siglec10 expression. Conclusion These data describe a role for adiponectin in enhancing pro-inflammatory signals in in vitro syncytialized trophoblasts. Additionally, this represents the first time the CD24/Siglec10 pathway has been implicated in a trophoblast response to a pro-inflammatory mediator. PMID: 21244561 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | In response to a query, CIRM said this afternoon that the new vice president of research and development, Ellen Feigal, would be paid $332,000. You can find the full story on her appointment here, with the updated salary information. | | | | | | | | | | | | | | | | | | | | | | | | The California stem cell agency today named Ellen Feigal, an executive at Amgen, Inc., to the new position of vice president for research and development.
Feigal(left) with Claire Pomeroy, dean of
the UC Davis School of Medicine in 2007
at an awards ceremony involving Feigal.
Pomeroy is also a member of the
CIRM board of directors.
She will begin work at the $3 billion research enterprise | | | | | | | | | | | | | | | | | | | | | | | | The California stem cell agency has released more information on issues coming before its directors next week, including a plan to pay some of the patient advocate members on its board up to $15,000 a year for their work.
Ten patient advocate members sit on the 29-member CIRM board of directors. The proposal would apply to six, those who serve on the Grants Working Group and the vice chair and | | | | | | | | | | | | | | | | | | | | | | | | | Rapid attachment of adipose stromal cells on resorbable polymeric scaffolds facilitates the one-step surgical procedure for cartilage and bone tissue engineering purposes. J Orthop Res. 2011 Jan 18; Authors: Jurgens WJ, Kroeze RJ, Bank RA, Ritt MJ, Helder MN The stromal vascular fraction (SVF) of adipose tissue provides an abundant source of mesenchymal stem cells. For clinical application, it would be beneficial to establish treatments in which SVF is obtained, seeded onto a scaffold, and returned into the patient within a single surgical procedure. In this study, we evaluated the suitability of both a macroporous poly(L-lactide-co-caprolactone) and a porous collagen type I/III scaffold for this purpose. Surprisingly, cell attachment was rapid (∼10 min) and sequestered the majority of adipose stem cells, as deduced from colony-forming unit assays. Proliferation occurred in both polymeric scaffolds. Upon chondrogenic induction, up-regulation of chondrogenic genes, production of glycosaminoglycans, and accumulation of collagen type II was observed, indicating differentiation of scaffold-attached SVF cells along the chondrogenic lineage. Osteogenic differentiation was achieved in both scaffold types, as visualized by up-regulation of osteogenic genes, increase of alkaline phosphatase production over time, and accumulation of bone sialoprotein and osteonectin. In conclusion, this study identifies both poly(L-lactide-co-caprolactone) and collagen type I/III as promising scaffold materials for rapid attachment of adipose stem cell-like (stromal) cells, enhancing the development of one-step surgical concepts for cartilage and bone tissue engineering. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res. PMID: 21246614 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fabrication of highly porous scaffolds for tissue engineering based on star-shaped functional poly(ε-caprolactone). Biotechnol Bioeng. 2011 Mar;108(3):694-703 Authors: Theiler S, Mela P, Diamantouros SE, Jockenhoevel S, Keul H, Möller M The potential of novel functional star-shaped poly(ε-caprolactone)s of controlled molecular weight and low molecular weight distribution bearing acrylate end groups as material for biomedical applications was demonstrated in this study. The polymers were functionalized via Michael-type addition of amino acid esters containing amino or thiol groups showing the potential for immobilization of biomolecules. Furthermore, scaffolds of different geometries were prepared by uniaxial freezing of polymer solutions followed by freeze drying. Different solvents and polymer concentrations were investigated, resulting in scaffolds with porosities between 76 and 96%. Mechanical properties of the scaffolds were investigated and the morphology was determined via scanning electron microscopy. Scaffolds with interconnected channels were prepared using benzene, 1,2-dichloroethane or dioxane as solvent. The tubular longitudinal pores in honeycomb arrangement extend throughout the full extent of the scaffolds (typical pore sizes: 20-100 µm). Biotechnol. Bioeng. 2011; 108:694-703. © 2010 Wiley Periodicals, Inc. PMID: 21246513 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Adipose derived stem cells: efficiency, toxicity, stability of BrdU labeling and effects on self-renewal and adipose differentiation. Mol Cell Biochem. 2011 Jan 19; Authors: Lequeux C, Oni G, Mojallal A, Damour O, Brown SA 5-bromo-2-deoxyurudine (BrdU) can be used as a methodological tool for in vivo investigations following in vitro prelabeling of isolated stem cells for subsequent cell tracking within the recipient host. The objective of this study was to determine how useful BrdU may be as a labeling modality for adipose derived stem cells (ASC) by examining BrdU toxicity, BrdU intracellular stability, and potential effects on ASC differentiation. Porcine and human ASC (pASC and hASC, respectively) were labeled with BrdU at 5 or 10 μM for 2, 6, 24, and 48 h. BrdU toxicity and stability over time in monolayer cultures, in 3-D collagen scaffolds implanted to a porcine model and after thawing from long-term storage were evaluated by MTT assays and immunohistochemistry. ASC differentiation was evaluated by Oil Red O staining. BrdU was not cytotoxic at all tested concentrations and incubation times. BrdU color intensity within each cell and the number of ASC labeled with BrdU decreased as a function of both incubation time and BrdU concentrations. Labeling intensities decreased over time and were undetectable after 6 passages for pASC and 4 passages for hASC. In 3-D scaffolds, BrdU-labeled ASC were identifiable after 90 days of in vitro cultures and for 30 days in a porcine model. BrdU did not prevent preadipocyte differentiation and BrdU labeling was still detectable after subsequent thawing after long-term storage of ASC. BrdU is an excellent candidate reagent to label and track ASC that will allow distinction between BrdU-labeled donor cells and host cells. The data provides a foundation for conducting future tissue engineering projects using BrdU-labeled ASC. PMID: 21246262 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Heparan Sulfate Proteoglycans Mediate Interstitial Flow Mechanotransduction Regulating MMP-13 Expression and Cell Motility via FAK-ERK in 3D Collagen. PLoS One. 2011;6(1):e15956 Authors: Shi ZD, Wang H, Tarbell JM Interstitial flow directly affects cells that reside in tissues and regulates tissue physiology and pathology by modulating important cellular processes including proliferation, differentiation, and migration. However, the structures that cells utilize to sense interstitial flow in a 3-dimensional (3D) environment have not yet been elucidated. Previously, we have shown that interstitial flow upregulates matrix metalloproteinase (MMP) expression in rat vascular smooth muscle cells (SMCs) and fibroblasts/myofibroblasts via activation of an ERK1/2-c-Jun pathway, which in turn promotes cell migration in collagen. Herein, we focused on uncovering the flow-induced mechanotransduction mechanism in 3D. PMID: 21246051 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | A reappraisal of saphenous vein grafting. Ann Saudi Med. 2011 Jan-Feb;31(1):62-71 Authors: Yuan SM, Jing H Autologous saphenous vein grafting has been broadly used as a bypass conduit, interposition graft, and patch graft in a variety of operations in cardiac, thoracic, neurovascular, general vascular, vascular access, and urology surgeries, since they are superior to prosthetic veins. Modified saphenous vein grafts (SVG), including spiral and cylindrical grafts, and vein cuffs or patches, are employed in vascular revascularization to satisfy the large size of the receipt vessels or to obtain a better patency. A loop SVG helps flap survival in a muscle flap transfer in plastic and reconstructive surgery. For dialysis or transfusion purposes, a straight or loop arteriovenous fistula created in the forearm or the thigh with an SVG has acceptable patency. The saphenous vein has even been used as a stent cover to minimize the potential complications of standard angioplasty technique. However, the use of saphenous vein grafting is now largely diminished in treating cerebrovascular disorders, superior vena cava syndrome, and visceral revascularization due to the introduction of angioplasty and stenting techniques. The SVG remains the preferable biomaterial in coronary artery bypass, coronary ostioplasty, free flap transfer, and surgical treatment of Peyronie disease. Implications associated with saphenous vein grafting in vascular access surgery for the purpose of dialysis and chemotherapy are considerable. Vascular cuffs and patches have been developed as an important and effective means of enhancing the patency rates of the grafts by linking the synthetic material to the receipt vessel. In addition, saphenous veins can be a cell source for tissue engineering. We review the versatile roles that saphenous vein grafting has played as well as its current status in therapy. PMID: 21245602 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Carbon nanotubes in neural interfacing applications. J Neural Eng. 2011 Jan 19;8(1):011001 Authors: Voge CM, Stegemann JP Carbon nanotubes (CNT) are remarkable materials with a simple and inert molecular structure that gives rise to a range of potentially valuable physical and electronic properties, including high aspect ratio, high mechanical strength and excellent electrical conductivity. This review summarizes recent research on the application of CNT-based materials to study and control cells of the nervous system. It includes the use of CNT as cell culture substrates, to create patterned surfaces and to study cell-matrix interactions. It also summarizes recent investigations of CNT toxicity, particularly as related to neural cells. The application of CNT-based materials to directing the differentiation of progenitor and stem cells toward neural lineages is also discussed. The emphasis is on how CNT surface chemistry and nanotopography can be altered, and how such changes can affect neural cell function. This knowledge can be applied to creating improved neural interfaces and devices, as well as providing new approaches to neural tissue engineering and regeneration. PMID: 21245526 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Optimized fabrication of Ca-P/PHBV nanocomposite scaffolds via selective laser sintering for bone tissue engineering. Biofabrication. 2011 Jan 18;3(1):015001 Authors: Duan B, Cheung WL, Wang M Biomaterials for scaffolds and scaffold fabrication techniques are two key elements in scaffold-based tissue engineering. Nanocomposites that consist of biodegradable polymers and osteoconductive bioceramic nanoparticles and advanced scaffold manufacturing techniques, such as rapid prototyping (RP) technologies, have attracted much attention for developing new bone tissue engineering strategies. In the current study, poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) microspheres and calcium phosphate (Ca-P)/PHBV nanocomposite microspheres were fabricated using the oil-in-water (O/W) and solid-in-oil-in-water (S/O/W) emulsion solvent evaporation methods. The microspheres with suitable sizes were then used as raw materials for scaffold fabrication via selective laser sintering (SLS), which is a mature RP technique. A three-factor three-level complete factorial design was applied to investigate the effects of the three factors (laser power, scan spacing, and layer thickness) in SLS and to optimize SLS parameters for producing good-quality PHBV polymer scaffolds and Ca-P/PHBV nanocomposite scaffolds. The plots of the main effects of these three factors and the three-dimensional response surface were constructed and discussed. Based on the regression equation, optimized PHBV scaffolds and Ca-P/PHBV scaffolds were fabricated using the optimized values of SLS parameters. Characterization of optimized PHBV scaffolds and Ca-P/PHBV scaffolds verified the optimization process. It has also been demonstrated that SLS has the capability of constructing good-quality, sophisticated porous structures of complex shape, which some tissue engineering applications may require. PMID: 21245522 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Biocompatibility of Electrospun Halloysite Nanotube-Doped Poly(Lactic-co-Glycolic Acid) Composite Nanofibers. J Biomater Sci Polym Ed. 2011 Jan 18; Authors: Qi R, Cao X, Shen M, Guo R, Yu J, Shi X Organic/inorganic hybrid nanofiber systems have generated great interest in the area of tissue engineering and drug delivery. In this study, halloysite nanotube (HNT)-doped poly(lactic-co-glycolic acid) (PLGA) composite nanofibers were fabricated via electrospinning and the influence of the incorporation of HNTs within PLGA nanofibers on their in vitro biocompatibility was investigated. The morphology, mechanical and thermal properties of the composite nanofibers were characterized by scanning electron microscopy (SEM), tensile test, differential scanning calorimetry and thermogravimetric analysis. The adhesion and proliferation of mouse fibroblast cells cultured on both PLGA and HNT-doped PLGA fibrous scaffolds were compared through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay of cell viability and SEM observation of cell morphology. We show that the morphology of the PLGA nanofibers does not appreciably change with the incorporation of HNTs, except that the mean diameter of the fibers increased with the increase of HNT incorporation in the composite. More importantly, the mechanical properties of the nanofibers were greatly improved. Similar to electrospun PLGA nanofibers, HNT-doped PLGA nanofibers were able to promote cell attachment and proliferation, suggesting that the incorporation of HNTs within PLGA nanofibers does not compromise the biocompatibility of the PLGA nanofibers. In addition, we show that HNT-doped PLGA scaffolds allow more protein adsorption than those without HNTs, which may provide sufficient nutrition for cell growth and proliferation. The developed electrospun HNT-doped composite fibrous scaffold may find applications in tissue engineering and pharmaceutical sciences. PMID: 21244744 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Tannic Acid Cross-linked Collagen Scaffolds and Their Anti-cancer Potential in a Tissue Engineered Breast Implant. J Biomater Sci Polym Ed. 2011 Jan 18; Authors: Cass CA, Burg KJ Tannic acid (TA) is a hydrolysable plant tannin, and it has been determined that TA functions as a collagen cross-linking agent through hydrogen-bonding mechanisms and hydrophobic effects. Since TA may have anti-tumor properties, it may be a viable cross-linking agent for collagen-based breast tissue scaffolds. The goal of this work was to determine if TA cross-linked scaffolds induce apoptotic processes in MCF-7 cancer cells, with minimal toxic effect on healthy D1 mesenchymal stem-like stromal cells. Cross-linked collagen scaffolds that were uniform, easily reproduced, easily characterized, and readily used in cell culture were manufactured. Thermal denaturation temperatures of the cross-linked scaffolds (68°C) were shown to be significantly higher when compared to those of uncross-linked scaffolds (55°C). Scanning electron microscopy images demonstrated the replacement of irregular collagen fibers with sheet-like structures upon cross-linking. The cross-linking solution concentration of TA that appears to be best for inducing apoptotic processes in MCF-7 cells, while minimizing toxic effect on D1 cells, is 1 mg/ml. At this concentration, the MCF-7 cell metabolic activity did not change over a 72-h period (i.e., proliferation was limited) while there was an increase in metabolic activity of D1 cells over the 72-h period. TA did appear to inhibit the production of lipid by D1 cells cultured in an adipogenic cocktail; in the future, the rate and duration of inhibition could be tailored to allow gradual bulking of the implant. The results suggest that the level of TA cross-linking can be modulated to provide optimal use in a tissue engineering composite. PMID: 21244722 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Surface Phosphorylation for Polyelectrolyte Complex of Chitosan and Its Sulfonated Derivative: Surface Analysis, Blood Compatibility and Adipose Derived Stem Cell Contact Properties. J Biomater Sci Polym Ed. 2011 Jan 18; Authors: Yeh HY, Lin JC Many studies have tried to look for the application of chitosan in tissue engineering since its structure is similar to glycoaminoglycans, the main components of the extracellular matrix. Previous studies had indicated that the incorporation of sulfonic or phosphonic functionalities would be beneficial to the growth of certain cells. However, no study has explored the effect of incorporation of both above-mentioned anionic functionalities onto the chitosan structure. In this study, we have surface-phosphorylated the polyelectrolyte film formed by chitosan and water-soluble sulfonated chitosan with the aim to incorporate phosphonic and sulfonic functionalities onto the film surface. Surface analyses by ESCA and ATR-FT-IR have shown that these two functional groups have been successfully grafted onto the surface, and that the ratio of P/S was dependent upon the weight ratio of phosphorylation agents added. Blood compatibility evaluation indicated that phosphorylated polyelectrolyte complexes extended the plasma recalcification time as compared to non-treated chitosan and direct-phosphorylated chitosan film. In addition, these phosphorylated polyelectrolyte complexes showed similar or slightly less platelet reactivity than the non-phosphorylated counterpart. In contrast, significant platelet activation and adhesion were noted on the direct-phosphorylated chitosan. This implicated the incorporation of sulfonic acid onto the phosphorylated surface can increase the platelet compatibility. An adipose-derived stem cell incubation study has demonstrated that the incorporation of both phosphonic and sulfonic acid functionalities onto the chitosan surface can enhance the stem cell growth. Therefore, the phosphorylated polyelectrolyte complexes were not only blood compatible but also stem cell compatible, and could be a novel biomaterial in tissue-engineering applications. PMID: 21244720 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of nitrogen-rich cell culture surfaces on type X collagen expression by bovine growth plate chondrocytes. Biomed Eng Online. 2011 Jan 18;10(1):4 Authors: Petit A, Demers CN, Girard-Lauriault PL, Stachura D, Wertheimer MR, Antoniou J, Mwale F ABSTRACT: BACKGROUND: Recent evidence indicates that osteoarthritis (OA) may be a systemic disease since mesenchymal stem cells (MSCs) from OA patients express type X collagen, a marker of late stage chondrocyte hypertrophy (associated with endochondral ossification). We recently showed that the expression of type X collagen was suppressed when MSCs from OA patients were cultured on nitrogen (N)-rich plasma polymer layers, which we call "PPE:N" (N-doped plasma-polymerized ethylene, containing up to 36 atomic percentage (at.% ) of N. METHODS: In the present study, we examined the expression of type X collagen in fetal bovine growth plate chondrocytes (containing hypertrophic chondrocytes) cultured on PPE:N. We also studied the effect of PPE:N on the expression of matrix molecules such as type II collagen and aggrecan, as well as on proteases (matrix metalloproteinase-13 (MMP-13) and molecules implicated in cell division (cyclin B2). Two other culture surfaces, "hydrophilic" polystyrene (PS, regular culture dishes) and nitrogen-containing cation polystyrene (Primaria), were also investigated for comparison. RESULTS: Results showed that type X collagen mRNA levels were suppressed when cultured for 4 days on PPE:N, suggesting that type X collagen is regulated similarly in hypertrophic chondrocytes and in human MSCs from OA patients. However, the levels of type X collagen mRNA almost returned to control value after 20 days in culture on these surfaces. Culture on the various surfaces had no significant effects on type II collagen, aggrecan, MMP-13, and cyclin B2 mRNA levels. CONCLUSION: Hypertrophy is diminished by culturing growth plate chondrocytes on nitrogen-rich surfaces a mechanism that is beneficial for MSC chondrogenesis. Furthermore, one major advantage of such "intelligent surfaces" over recombinant growth factors for tissue engineering and cartilage repair is potentially large cost-saving. PMID: 21244651 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | BRAF, HRAS, KRAS, NRAS and CDKN2A genes analysis in cultured melanocytes used for vitiligo treatment. Int J Dermatol. 2011 Feb;50(2):180-3 Authors: Czajkowski R Background Cultured pigment cells are increasingly being used in the treatment of stable vitiligo. The melanocyte growth media contain synthetic and human recombinant mitogenic factors. High concentration of growth factors, increased melanin biosynthesis, and the rapid cell cycle progression may lead to the genetic material damage and the initiation of melanocyte malignant transformation in cell culture conditions. Mutations of genes of the RAS/RAF/MEK/ERK signaling pathway and CDKN2A gene are often found in the early stages of melanoma development. 12-O-Tetradecanoyl-phorbol-13-acetate (TPA)/phorbol 12-myristate 13-acetate (PMA) is considered to be an oncogenic factor, but there is no evidence that it is responsible for melanomagenesis initiation. The goal of this research was to assess the risk of the development of mutations in selected genes of the RAS/RAF/MEK/ERK signaling pathway and CDKN2A gene during the culturing of pigment cells in various growth media. Methods Three-hundred melanocyte cultures were established in 10 various growth media. The population doubling time of cultured cells was calculated for all the tested growth media. Cytogenetic analysis was carried out on the HRAS (exon 1 and 2), KRAS (exon 1 and 2), NRAS (exon 1 and 2), BRAF (exon 11 and 15), and CDKN2A (exon 1) genes. Results Our study revealed that TPA and high concentrations of other growth factors intensify the proliferation of pigment cells, without the risk of damage to the analyzed genes. Conclusions It is necessary to carry out further similar studies on other signaling pathways to confirm cultured melanocytes transplantation safety. PMID: 21244382 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | The influence of nanoscale topographical cues on initial osteoblast morphology and migration. Eur Cell Mater. 2010;20:329-43 Authors: Lamers E, van Horssen R, te Riet J, van Delft FC, Luttge R, Walboomers XF, Jansen JA The natural environment of a living cell is not only organized on a micrometer, but also on a nanometer scale. Mimicking such a nanoscale topography in implantable biomaterials is critical to guide cellular behavior. Also, a correct positioning of cells on biomaterials is supposed to be very important for promoting wound healing and tissue regeneration. The exact mechanism by which nanotextures can control cellular behavior are thus far not well understood and it is thus far unknown how cells recognize and respond to certain surface patterns, whereas a directed response appears to be absent on other pattern types. Focal adhesions (FAs) are known to be involved in the process of specific pattern recognition and subsequent response by cells. In this study, we used a high throughput screening "Biochip" containing 40 different nanopatterns to evaluate the influence of several nanotopographical cues like depth, width, (an)isotropy and spacing (ridge-groove ratio) on osteoblast behavior. Microscopical analysis and time lapse imaging revealed that an isotropic topography did not alter cell morphology, but it highly induced cell motility. Cells cultured on anisotropic topographies on the other hand, were highly elongated and aligned. Time-lapse imaging revealed that cell motility is highly dependent on the ridge-groove ratio of anisotropic patterns. The highest motility was observed on grooves with a ratio of 1:3, whereas the lowest motility was observed on ratios of 1:1 and 3:1. FA measurements demonstrated that FA-length decreased with increasing motility. From the study it can be concluded that osteoblast behavior is tightly controlled by nanometer surface features. PMID: 21061239 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Nondestructive assessment of engineered cartilage constructs using near-infrared spectroscopy. Appl Spectrosc. 2010 Oct;64(10):1160-6 Authors: Baykal D, Irrechukwu O, Lin PC, Fritton K, Spencer RG, Pleshko N Noninvasive assessment of engineered cartilage properties would enable better control of the developing tissue towards the desired structural and compositional endpoints through optimization of the biochemical environment in real time. The objective of this study is to assess the matrix constituents of cartilage using near-infrared spectroscopy (NIRS), a technique that permits full-depth assessment of developing engineered tissue constructs. Mid-infrared (mid-IR) and NIR data were acquired from full-thickness cartilage constructs that were grown up to 4 weeks with and without mechanical stimulation. Correlations were assessed between established mid-IR peak areas that reflect the relative amount of collagen (amide I, amide II, and 1338 cm(-1)) and proteoglycan (PG), (850 cm(-1)), and the integrated area of the NIR water absorbance at 5190 cm(-1). This analysis was performed to evaluate whether simple assessment of the NIR water absorbance could yield information about matrix development. It was found that an increase in the mid-IR PG absorbance at 850 cm(-1) correlated with the area of the NIR water peak (Spearman's rho = 0.95, p < 0.0001). In the second analysis, a partial least squares method (PLS1) was used to assess whether an extended NIR spectral range (5400-3800 cm(-1)) could be utilized to predict collagen and proteoglycan content of the constructs based on mid-IR absorbances. A subset of spectra was randomly selected as an independent prediction set in this analysis. Average of the normalized root mean square errors of prediction of first-derivative NIR spectral models were 7% for 850 cm(-1) (PG), 11% for 1338 cm(-1) (collagen), 8% for amide II (collagen), and 8% for amide I (collagen). These results demonstrate the ability of NIRS to monitor macromolecular content of cartilage constructs and is the first step towards employing NIR to assess engineered cartilage in situ. PMID: 20925987 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
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