|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | We have dropped the hook in Panama in a bay near the entrance to the Panama Canal, where behemoths of the sea parade by hourly on their way to the Atlantic Ocean. We are catching up on California stem cell affairs and hope to have a fresh posting soon. | | | | | | | | | | | | | | | | | | | | | | | | | All-arthroscopic meniscus repair of avascular and biologically at-risk meniscal tears. Instr Course Lect. 2011;60:439-52 Authors: Kessler MW, Sgaglione NA Meniscal repair strategies have evolved over time from a more invasive open method to less invasive, all-arthroscopic approaches. Novel devices and surgical techniques currently enable the successful arthroscopic placement of biomechanically optimal sutures that provide compression across the tear site with less potential surgical morbidity. Current techniques do not require accessory posteromedial or posterolateral incisions and significantly reduce the incidence of complications and pain associated with more invasive surgery. Along with these improved methods, the indications for meniscal repair are expanding to include tear patterns previously considered biologically at risk for poor healing. More recently, with the addition of biologic augmentation methods, such as the introduction of platelet- rich plasma as well as reported tissue engineering advances, it may be possible to continue to broaden the indications and success of meniscal preservation through repair and replacement. PMID: 21553790 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Flow dynamics within a bioreactor for tissue engineering by residence time distribution analysis combined with fluorescence and magnetic resonance imaging to investigate forced permeability and apparent diffusion coefficient in a perfusion cell culture chamber. Biotechnol Bioeng. 2011 May 6; Authors: Dubois J, Tremblay L, Lepage M, Vermette P This study reveals that residence time distribution (RTD) analysis with pH monitoring after acid bolus injection can be used to globally study the flow dynamics of a perfusion bioreactor, while fluorescence microscopy and magnetic resonance imaging (MRI) were used to locally investigate mass transport within a hydrogel scaffold seeded or not with cells. The bioreactor used in this study is a closed-loop tubular reactor. A dispersion model in one dimension has been used to describe the non-ideal behavior of the reactor. From open-loop experiments (single-cycle analysis), the presence of stagnant zones and back mixing were observed. The impact of the flow rate, the compliance chamber volume and mixing were investigated. Intermediate flows (30, 45, 60 and 90 mL·min(-1) ) had no effect over RTD function expressed in reduced time (θ). Lower flow rates (5 and 15 mL·min(-1) ) were associated to smaller extent of dispersion. The compliance chamber volume greatly affected the dynamic of the RTD function, while the effects of mixing and flow were small to non-significant. An empirical equation has been proposed to localize minima of the RTD function and to predict Pe(r) . Finally, cells seeded in a gelatin gel at a density of 800,000 cells·mL(-1) had no effect over the permeability and the apparent diffusion coefficient, as revealed by fluorescent microscopy and MRI experiments. Biotechnol. Bioeng. © 2011 Wiley Periodicals, Inc. PMID: 21557203 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Extruded collagen fibres for tissue engineering applications: effect of crosslinking method on mechanical and biological properties. J Mater Sci Mater Med. 2011 May 10; Authors: Enea D, Henson F, Kew S, Wardale J, Getgood A, Brooks R, Rushton N Reconstituted collagen fibres are promising candidates for tendon and ligament tissue regeneration. The crosslinking procedure determines the fibres' mechanical properties, degradation rate, and cell-fibre interactions. We aimed to compare mechanical and biological properties of collagen fibres resulting from two different types of crosslinking chemistry based on 1-ethyl-3-(3-dimethyllaminopropyl)carbodiimide (EDC). Fibres were crosslinked with either EDC or with EDC and ethylene-glycol-diglycidyl-ether (EDC/EGDE). Single fibres were mechanically tested to failure and bundles of fibres were seeded with tendon fibroblasts (TFs) and cell attachment and proliferation were determined over 14 days in culture. Collagen type I and tenascin-C production were assessed by immunohistochemistry and dot-blotting. EDC chemistry resulted in fibres with average mechanical properties but the highest cell proliferation rate and matrix protein production. EDC/EGDE chemistry resulted in fibres with improved mechanical properties but with a lower biocompatibility profile. Both chemistries may provide useful structures for scaffolding regeneration of tendon and ligament tissue and will be evaluated for in vivo tendon regeneration in future experiments. PMID: 21556975 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Ex vivo cartilage defect model for the evaluation of cartilage regeneration using mesenchymal stem cells. J Biosci Bioeng. 2011 Mar;111(3):357-64 Authors: Iwai R, Fujiwara M, Wakitani S, Takagi M An ex vivo cartilage defect model for the evaluation of cartilage regeneration using mesenchymal stem cells (MSCs) was developed. Porcine chondrocytes and human MSCs were transplanted into cartilage defects created on the porcine osteochondral and chondral discs and cultivated for 3 weeks. Although the regeneration of cartilage-like tissues was observed after the transplantation of chondrocytes to defects on both of the osteochondral and chondral discs, the transplanted MSCs formed cartilage-like tissues only in the defect on the chondral disc, in which an in vivo cartilage-like structure was partly observed, and a degraded tissue was observed in the defect on the osteochondral disc. The effects of medium additives such as serum, transforming growth factor-β3 (TGF-β3), and fibroblast growth factor-2, and the transfection of TGF-β3 gene to MSCs could be clearly estimated using the cartilage defect model. In conclusion, a chondral disc with defects is useful for evaluating cartilage regeneration using MSCs. PMID: 21126909 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Improved human tenocyte proliferation and differentiation in vitro by optimized silk degumming. Biomed Mater. 2011 May 10;6(3):035010 Authors: Wang X, Qiu Y, Carr AJ, Triffitt JT, Sabokbar A, Xia Z Tendon disorders are common clinical conditions. Tendon tissue engineering provides a new approach for tendon repair by integrating engineered substitutes with their native counterparts. Silk is considered to be a promising candidate for tendon engineering because of its biological and mechanical properties. However, a major concern with using silk for biomedical applications is the immune responses generated by sericin, a glue-like protein that coats the silk fibres. This study improves the existing protocols for silk 'degumming' which removes sericin and enables preparation of silk that is suitable for tendon regeneration. Bombyx mori silks were treated by sequential treatments with different proteases. The efficiency of degumming was determined by measuring weight loss, picric acid and carmine staining and scanning electron microscopy. To evaluate the cellular responses after degumming, the growth and differentiation of human tenocytes on silks were examined. The results showed that sequential protease treatment effectively degummed raw silks. The sequentially degummed silks showed enhanced tenocyte proliferation and upregulated mRNA levels of tendon markers. Thick cell multilayers formed on the treated silks, with cells and collagen fibres penetrating into the spaces in individual silk filaments, resulting in a structure resembling human tendon. PMID: 21555843 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The effect of mesenchymal stromal cell - hyaluronic acid hydrogel constructs on immunophenotype of macrophages. Tissue Eng Part A. 2011 May 10; Authors: Hanson SE, King SN, Kim J, Chen X, Thibeault S, Hematti P During the past several years, multipotent mesenchymal stromal cells (MSCs) have rapidly moved from in vitro and animal studies into clinical trials as a therapeutic modality potentially applicable to a wide range of disorders. It has been proposed that ex vivo culture expanded MSCs exert their tissue regeneration potential through their immunomodulatory and anti-inflammatory properties, and paracrine effects more than their ability to differentiate into multiple tissue lineages. Since extracellular matrix deposition and tissue support is also one of many physiological roles of MSCs, there is increasing interest in their potential use for tissue engineering, particularly in combination with extracellular matrix-based scaffolds such as hyaluronic acid (HA). We investigated the effect of MSCs on immunophenotype of macrophages in the presence of an HA - hydrogel scaffold using a unique 3D coculture system. MSCs were encapsulated in the hydrogel and peripheral blood CD14+ monocyte-derived macrophages plated in direct contact with the MSC-gel construct. To determine the immunophenotype of macrophages, we looked at the expression of cell surface markers CD14, CD16, CD206, and HLA-DR by flow cytometry. MSCs and macrophages cultured on the HA-hydrogel remained viable and were able to be recovered from the construct. There was a significant difference in the immunophenotype observed between monocyte-derived macrophages cultured on the HA scaffold compared to tissue culture polystyrene. Macrophages cultured on gels with MSCs expressed lower CD16 and HLA-DR with higher expression of CD206, indicating the least inflammatory profile overall, compatible with the immunophenotype of alternatively activated macrophages. Development of macrophages, with this immunophenotype, upon interaction with the MSC-hydrogel constructs may play a potentially significant role in tissue repair when using a cellular-biomaterial therapeutic approach. PMID: 21554192 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of seeding using an avidin-biotin binding system on the attachment of periodontal ligament fibroblasts to nanohydroxyapatite scaffolds: three-dimensional culture. J Periodontal Implant Sci. 2011 Apr;41(2):73-8 Authors: Jang YJ, Jung IH, Park JC, Jung UW, Kim CS, Lee YK, Kim CK, Choi SH For periodontal tissue engineering, it is a primary requisite and a challenge to select the optimum types of cells, properties of scaffold, and growth factor combination to reconstruct a specific tissue in its natural form and with the appropriate function. Owing to fundamental disadvantages associated with using a two-dimensional substrate, several methods of seeding cells into three-dimensional scaffolds have been reported and the authors have asserted its usefulness and effectiveness. In this study, we explore the cell attachment of periodontal ligament fibroblasts on nanohydroxyapatite (n-HA) scaffold using avidin biotin binding system (ABBS). PMID: 21556257 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Transplantation of Human Hematopoietic Cells for Extracellular Matrix Protein Deficiency in Epidermolysis Bullosa. Stem Cells. 2011 Apr 19; Authors: Tolar J, Blazar BR, Wagner JE The skin is constantly exposed to environmental insults and requires effective repair processes to maintain its protective function. Wound healing is severely compromised in people with congenital absence of structural proteins of the skin, such as in dystrophic epidermolysis bullosa, a severe congenital mechanobullous disorder caused by mutations in collagen type VII. Remarkably, stem cell transplantation can ameliorate deficiency of this skin-specific structural protein in both animal models and in children with the disorder. Healthy donor cells from the hematopoietic graft migrate to the injured skin; simultaneously, there is an increase in the production of collagen type VII, increased skin integrity and reduced tendency to blister formation. How hematogenous stem cells from bone marrow and cord blood can alter skin architecture and wound healing in a robust, clinically meaningful way is unclear. We review the data and the resulting hypotheses that have a potential to illuminate the mechanisms for these effects. Further modifications in the use of stem cell transplantation as a durable source of extra-cellular matrix proteins may make this regenerative medicine approach effective in other cutaneous and extra-cutaneous conditions. PMID: 21557391 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Dedifferentiation of Human Primary Thyrocytes into Multilineage Progenitor Cells without Gene Introduction. PLoS One. 2011;6(4):e19354 Authors: Suzuki K, Mitsutake N, Saenko V, Suzuki M, Matsuse M, Ohtsuru A, Kumagai A, Uga T, Yano H, Nagayama Y, Yamashita S While identification and isolation of adult stem cells have potentially important implications, recent reports regarding dedifferentiation/reprogramming from differentiated cells have provided another clue to gain insight into source of tissue stem/progenitor cells. In this study, we developed a novel culture system to obtain dedifferentiated progenitor cells from normal human thyroid tissues. After enzymatic digestion, primary thyrocytes, expressing thyroglobulin, vimentin and cytokeratin-18, were cultured in a serum-free medium called SAGM. Although the vast majority of cells died, a small proportion (∼0.5%) survived and proliferated. During initial cell expansion, thyroglobulin/cytokeratin-18 expression was gradually declined in the proliferating cells. Moreover, sorted cells expressing thyroid peroxidase gave rise to proliferating clones in SAGM. These data suggest that those cells are derived from thyroid follicular cells or at least thyroid-committed cells. The SAGM-grown cells did not express any thyroid-specific genes. However, after four-week incubation with FBS and TSH, cytokeratin-18, thyroglobulin, TSH receptor, PAX8 and TTF1 expressions re-emerged. Moreover, surprisingly, the cells were capable of differentiating into neuronal or adipogenic lineage depending on differentiating conditions. In summary, we have developed a novel system to generate multilineage progenitor cells from normal human thyroid tissues. This seems to be achieved by dedifferentiation of thyroid follicular cells. The presently described culture system may be useful for regenerative medicine, but the primary importance will be as a tool to elucidate the mechanisms of thyroid diseases. PMID: 21556376 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Phosphorus-containing polymers: a great opportunity for the biomedical field. Biomacromolecules. 2011 May 10; Authors: Monge S, Canniccioni B, Graillot A, Robin JJ This review is focused on the growing interest brought to phosphorus-containing organic materials for applications in the biomedical field, mainly due to their properties such as biocompatibility, hemocompatibility, and protein adsorption resistance. It mainly describes relevant works achieved on these materials for various applications: dentistry, regenerative medicine, and drug delivery. A special attention was given to 2-methacryloyloxyethyl phosphorylcholine (MPC) monomer as the latter appeared of great importance because of its biomimetic structure due to the presence of the phospholipid group on its structure. As a result, a lot of research effort is currently concentrated on the development of phosphorylcholine-containing (co)polymers which represent a promising class of materials. PMID: 21553908 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Concise Review: Quiescent and Active States of Endogenous Adult Neural Stem Cells: Identification and Characterization. Stem Cells. 2011 Apr 19; Authors: Wang YZ, Plane JM, Jiang P, Zhou CJ, Deng W The adult mammalian central nervous system (CNS) lacks the capacity for regeneration, making it a highly sought-after topic for researchers. The identification of neural stem cells (NSCs) in the adult CNS wiped out a long-held dogma that the adult brain contains a set number of neurons and is incapable of replacing them. The discovery of adult NSCs (aNSCs) stoked the fire for researchers who dream of brain self-repair. Unfortunately, the quiescent nature and limited plasticity of aNSCs diminish their regenerative potential. Recent studies evaluating aNSC plasticity under pathological conditions indicate that a switch from quiescent to active aNSCs in neurogenic regions plays an important role in both repairing the damaged tissue and preserving progenitor pools. Here, we summarize the most recent findings and present questions about characterizing the active and quiescent aNSCs in major neurogenic regions, and factors for maintaining their active and quiescent states, hoping to outline an emerging view for promoting the endogenous aNSC-based regeneration. PMID: 21557389 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Efficacy and safety of low-dose propiverine in patients with lower urinary tract symptoms/benign prostatic hyperplasia with storage symptoms: a prospective, randomized, single-blinded and multicenter clinical trial. Korean J Urol. 2011 Apr;52(4):274-8 Authors: Bae JH, Kim SO, Yoo ES, Moon KH, Kyung YS, Kim HJ The aim of this study was to evaluate whether low-dose anticholinergics combined with an α1-receptor antagonist would continue the effect of an alpha-blocker, decrease the side effects of anticholinergics, and improve the symptoms of lower urinary tract symptoms/benign prostatic hyperplasia (LUTS/BPH). PMID: 21556215 [PubMed - in process] | | | | | | | | | |  | |  | |  |
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