| Utah ethicist heads stem cell panel
September 22, 2009 at 5:53 pm
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| Private umbilical cord banking not cost-effective, UCSF research shows
September 22, 2009 at 5:53 pm
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| PacifiCord Secures Sterile Cord Blood Collection Bag
September 22, 2009 at 12:09 pm
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| StemCells, Inc. Announces Initiatives to Advance Cell-Based Technologies for Pharmaceutical Industry and Research Applications
September 22, 2009 at 11:04 am
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| Mesenchymal stem cells derived from dental tissues vs. those from other sources: their biology and role in regenerative medicine.
September 22, 2009 at 7:31 am
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| | Mesenchymal stem cells derived from dental tissues vs. those from other sources: their biology and role in regenerative medicine. J Dent Res. 2009 Sep;88(9):792-806 Authors: Huang GT, Gronthos S, Shi S To date, 5 different human dental stem/progenitor cells have been isolated and characterized: dental pulp stem cells (DPSCs), stem cells from exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSCs), stem cells from apical papilla (SCAP), and dental follicle progenitor cells (DFPCs). These postnatal populations have mesenchymal-stem-cell-like (MSC) qualities, including the capacity for self-renewal and multilineage differentiation potential. MSCs derived from bone marrow (BMMSCs) are capable of giving rise to various lineages of cells, such as osteogenic, chondrogenic, adipogenic, myogenic, and neurogenic cells. The dental-tissue-derived stem cells are isolated from specialized tissue with potent capacities to differentiate into odontogenic cells. However, they also have the ability to give rise to other cell lineages similar to, but different in potency from, that of BMMSCs. This article will review the isolation and characterization of the properties of different dental MSC-like populations in comparison with those of other MSCs, such as BMMSCs. Important issues in stem cell biology, such as stem cell niche, homing, and immunoregulation, will also be discussed. PMID: 19767575 [PubMed - in process] |
| Reducing the mystery of neuronal differentiation.
September 22, 2009 at 7:31 am
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| | Reducing the mystery of neuronal differentiation. Cell. 2009 Sep 18;138(6):1062-4 Authors: Novitch BG, Butler SJ In the developing nervous system, neural progenitors exit the cell cycle and differentiate on a precise schedule, yet the mechanisms driving this process remain poorly defined. Yan et al. (2009) now identify a thiol-redox reaction mediated by the membrane protein GDE2 and the peroxiredoxin protein Prdx1 that promotes neurogenesis. PMID: 19766560 [PubMed - in process] |
| Tgfbeta Signal Inhibition Cooperates in the Induction of iPSCs and Replaces Sox2 and cMyc.
September 22, 2009 at 7:31 am
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| | Tgfbeta Signal Inhibition Cooperates in the Induction of iPSCs and Replaces Sox2 and cMyc. Curr Biol. 2009 Sep 16; Authors: Maherali N, Hochedlinger K Ectopic expression of Oct4, Sox2, cMyc, and Klf4 confers a pluripotent state upon several differentiated cell types, generating induced pluripotent stem cells (iPSCs) [1-8]. iPSC derivation is highly inefficient, and the underlying mechanisms are largely unknown. This low efficiency suggests the existence of additional cooperative factors whose identification is critical for understanding reprogramming. In addition, the therapeutic use of iPSCs relies on the development of efficient nongenetic means of factor delivery, and although a handful of replacement molecules have been identified, their use yields a further reduction to the already low reprogramming efficiency [9-11]. Thus, the identification of compounds that enhance rather than solely replace the function of the reprogramming factors will be of great use. Here, we demonstrate that inhibition of Tgfbbeta signaling cooperates in the reprogramming of murine fibroblasts by enabling faster, more efficient induction of iPSCs, whereas activation of Tgfbeta signaling blocks reprogramming. In addition to exhibiting a strong cooperative effect, the Tgfbeta receptor inhibitor bypasses the requirement for exogenous cMyc or Sox2, highlighting its dual role as a cooperative and replacement factor. The identification of a highly characterized pathway operating in iPSC induction will open new avenues for mechanistic dissection of the reprogramming process. PMID: 19765992 [PubMed - as supplied by publisher] |
| Mesenchymal stem cells and cartilage in situ regeneration.
September 22, 2009 at 7:31 am
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| | Mesenchymal stem cells and cartilage in situ regeneration. J Intern Med. 2009 Oct;266(4):390-405 Authors: Richter W Cartilage repair is a very successful pioneering area of regenerative medicine in which techniques of in situ regeneration and cell and tissue transplantation dominate over cell-free approaches to generate durable neocartilage. This review concentrates on advantages and limitations of mesenchymal stem cell (MSC)-based cartilage repair strategies induced by marrow stimulation. Detailed knowledge on the biology of MSC will be discussed in light of the requirements for MSC recruitment, retention, proliferation and chondrogenic differentiation. An improved microenvironment with timely correlated signals from biomaterials, growth factors, proteases, adjacent cartilage and subchondral bone may be key to a third generation of techniques to regenerate hyaline cartilage. PMID: 19765182 [PubMed - in process] |
| Regenerative medicine: a 2009 overview.
September 22, 2009 at 7:31 am
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| | Regenerative medicine: a 2009 overview. J Intern Med. 2009 Oct;266(4):303-10 Authors: Andersson ER, Lendahl U The rapidly evolving field of regenerative medicine holds much promise for cell-based therapies for a range of debilitating conditions from spinal cord injury to haematological and neurological diseases. The groundbreaking discovery of induced pluripotent stem (iPS) cells has offered new perspectives on disease progression and the possibility of patient-specific cell transplants. In this review we first give a brief history of the field of regenerative medicine and then discuss the current state of regenerative medicine with a focus on embryonic stem cells and iPS cells. In order to keep abreast with this rapidly developing field, the Journal of Internal Medicine organized a 2-day Symposium, on March 12-13(th) 2009, at the Karolinska Insitute in Stockholm, which featured talks by 19 leading scientists in the field of regenerative medicine. In this review, we discuss the Symposium and introduce six accompanying review articles, by Symposium speakers, which focus on some of the topics discussed at the meeting. PMID: 19765176 [PubMed - in process] |
| [Novel human embryonic stem cell lines C612 and C910]
September 22, 2009 at 7:31 am
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| | [Novel human embryonic stem cell lines C612 and C910] Tsitologiia. 2009;51(7):551-8 Authors: Novel human embryonal stem cell lines C612 and C910 have been established from hatching blastocytes. Cells were cultivated in mTeST medium on mouse fibroblast feeder-layers. They express common pluripotent markers such as alkaline phosphatase, Oct 3/4, SEEA-4, Nanog, Rex1. Immunophenotyping of these cells by flow cytometry revealed expression of CD90 (Thy-1) and CD117 (c-kit) antigens and weak or no expression of CD13, CD34, CD45, CD130, HLA class I and HLA class II antigens. This pattern of surface antigen expression is common for human embryonic stem cells. G-banding assay of C612 and C910 metaphase plates showed that karyotypic structure of these cells was normal both in chromosome number and structure. The cells are pluripotent because of their capability to generate embryoid bodies, undergo spontaneous differentiation and express markers of all germ layers: nestin, keratin, vimentin (ectoderm), alpha-fetoprotein (entoderm), and muscle alpha-actinin (mesoderm). Thus, C612 and C910 cells have all attributes of typical human embryonic stem cells (diploid, capable of self-renewal, express pluripotent markers and differentiate into three germ layers) and may be of potential use for fundamental and regenerative medicine researches. PMID: 19764646 [PubMed - in process] |
| Fully functional bioengineered tooth replacement as an organ replacement therapy.
September 22, 2009 at 7:31 am
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| | Fully functional bioengineered tooth replacement as an organ replacement therapy. Proc Natl Acad Sci U S A. 2009 Aug 11;106(32):13475-80 Authors: Ikeda E, Morita R, Nakao K, Ishida K, Nakamura T, Takano-Yamamoto T, Ogawa M, Mizuno M, Kasugai S, Tsuji T Current approaches to the development of regenerative therapies have been influenced by our understanding of embryonic development, stem cell biology, and tissue engineering technology. The ultimate goal of regenerative therapy is to develop fully functioning bioengineered organs which work in cooperation with surrounding tissues to replace organs that were lost or damaged as a result of disease, injury, or aging. Here, we report a successful fully functioning tooth replacement in an adult mouse achieved through the transplantation of bioengineered tooth germ into the alveolar bone in the lost tooth region. We propose this technology as a model for future organ replacement therapies. The bioengineered tooth, which was erupted and occluded, had the correct tooth structure, hardness of mineralized tissues for mastication, and response to noxious stimulations such as mechanical stress and pain in cooperation with other oral and maxillofacial tissues. This study represents a substantial advance and emphasizes the potential for bioengineered organ replacement in future regenerative therapies. PMID: 19666587 [PubMed - indexed for MEDLINE] |
| Connexin 43 as a signaling platform for increasing the volume and spatial distribution of regenerated tissue.
September 22, 2009 at 7:31 am
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| | Connexin 43 as a signaling platform for increasing the volume and spatial distribution of regenerated tissue. Proc Natl Acad Sci U S A. 2009 Aug 11;106(32):13219-24 Authors: Rosselló RA, Wang Z, Kizana E, Krebsbach PH, Kohn DH Gap junction intercellular communication (GJIC) is ubiquitous in the majority of vertebrate cells and is required for the proper development of most tissues. The loss of gap junction-mediated cell-to-cell communication leads to compromised development in many tissues and organs. Because cells constantly interact through gap junctions to coordinate tissue functions and homeostasis, we hypothesized that increasing cell-to-cell communication, via genetically engineering cells to overexpress gap junction proteins, could enhance cell differentiation in the interior regions of 3D tissue equivalents, thereby increasing the ability to regenerate larger and more uniform volumes of tissue. To test this hypothesis, we used bone as a model tissue because of the difficulty in achieving spatially uniform bone regeneration in 3D. In bone marrow stromal cells (BMSC), GJIC and osteogenic differentiation were compromised in 3D cultures relative to 2D monolayers and in the core of 3D cultures relative to the surface. Overexpression of connexin 43 (Cx43) via transduction of BMSCs with a lentivirus overcame this problem, enhancing both the magnitude and spatial distribution of GJIC and osteogenic differentiation markers throughout 3D constructs. Transplantation of cells overexpressing Cx43 resulted in an increased volume fraction and spatial uniformity of bone in vivo, relative to nontransduced BMSCs. Increased GJIC also enhanced the effect of a potent osteoinductive agent (BMP-7), suggesting a synergism between the soluble factor and GJIC. These findings present a platform to improve cell-to-cell communication in 3D and to achieve uniformly distributed tissue regeneration in 3D. PMID: 19628695 [PubMed - indexed for MEDLINE] |
| 6th Global College of Neuroprotection and Neuroregeneration, annual meeting.
September 22, 2009 at 7:31 am
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| | 6th Global College of Neuroprotection and Neuroregeneration, annual meeting. Expert Rev Neurother. 2009 Jul;9(7):941-7 Authors: Sharma HS, Sharma A The 6th Global College of Neuroprotection and Neuroregeneration (GCNN) and 5th Society for Study on Neuroplasticity and Neuroregeneration (SSNN) conference was held jointly in the Hilton Hotel, Vienna, Austria, 1-4 March 2009. This was the second annual joint conference of the two societies and it was highly successful from a scientific point of view, as it saw a gathering of the top basic and clinical scientists whose research is currently at the cutting edge of neuroscience. This conference saw 86 invited lectures from carefully selected leading scientists from around the world, along with 56 posters of young scientists researching of a focal theme. Over the 3 days, in 32 sessions, new developments in neuroprotection and new ways to enhance neuroregeneration were discussed intensively among more than 600 delegates. In addition, approximately 40 representatives of drug companies, five representatives from scientific publishers and 14 representatives from scientific instruments and supplies-related industries also actively participated in this huge neuroscience event. The GCNN and SSNN conference achieved a new milestone in scientific success in Vienna and established an excellent new working collaboration among the participants in a pleasant, enriched environment with several social gatherings. PMID: 19589044 [PubMed - indexed for MEDLINE] |
| Porous hollow membrane sheet for tissue engineering applications.
September 22, 2009 at 7:17 am
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| | Porous hollow membrane sheet for tissue engineering applications. J Biomed Mater Res A. 2009 Sep 18; Authors: Hadjizadeh A, Mohebbi-Kalhori D In spite of the present advances in the scaffolds fabrication and bioreactor systems, the ability to create functional thick tissue masses in vitro is still a great tissue engineering challenge. To overcome this problem, the fabrication of a capillary bed, for nutrient supply to and waste product removal from the tissue engineering construct as it grows, is essential. However, the technical construction of a capillary-like architecture is complex and challenging. This study reports, for the very first time, a simple method to design and fabricate a porous hollow membrane sheet (PHMsh) to provide both a capillary bed and a scaffold to support tissue growth. The PHMsh composed of a flexible porous sheet involving parallel porous channels and can be used as flat-, rolled-, or sandwiched-shape scaffold. The PHMsh was fabricated from poly(epsilon-caprolactone) polymer solution using solvent casting methods (i.e., immersion precipitation and air casting). Optical microscopy and scanning electron microscopy were used for the morphological analyses. The PHMsh was surface treated using n-hepthylamine plasma polymer (HApp) and X-ray photoelectron spectroscopy confirmed successful surface coating. Human umbilical vein endothelial cells (HUVECs) and fibroblast cells were used to evaluate the capability of PHMsh toward cell adhesion. The HApp coating enhanced both HUVEC and fibroblast cells adhesion. The obtained preliminary results demonstrated the successful fabrication of the PHMsh, with potential application for tissue engineering scaffolds, particularly in large tissue mass generation under perfusion systems in vitro, which is our future research direction. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2009. PMID: 19768796 [PubMed - as supplied by publisher] |
| The topographical effect of electrospun nanofibrous scaffolds on the in vivo and in vitro foreign body reaction.
September 22, 2009 at 7:17 am
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| | The topographical effect of electrospun nanofibrous scaffolds on the in vivo and in vitro foreign body reaction. J Biomed Mater Res A. 2009 Sep 18; Authors: Cao H, McHugh K, Chew SY, Anderson JM Topographical cues play an important role in influencing cellular behavior and are considered as significant parameters to be controlled in tissue engineering applications. This work investigated the biocompatibility with regard to scaffold architecture and topographical effect of nanofibrous scaffolds on the in vivo and in vitro foreign body reaction. Random and aligned polycaprolactone (PCL) nanofibers were fabricated by electrospinning technique, with diameters of 313 +/- 5 nm and 506 +/- 24 nm, respectively. Primary monocytes isolated from five human donors were cultured on PCL nanofibers, PCL film, and RGD-coated glass in vitro and cell density and morphology was evaluated at time points of day 0 (2 h), day 3, day 7, and day 10. The in vivo study was carried out by implanting PCL nanofibers and film scaffolds subcutaneously in rats to test the biocompatibility and host response at time points of week 1, week 2, and week 4. The in vitro studies revealed that the initial monocyte adhesion on the aligned fiber scaffold was significantly less (p < 0.001) when compared to the random fiber scaffold. The in vivo study showed that the thicknesses of fibrous capsule on fibrous scaffolds were 7.55 +/- 0.54 mum for aligned fibers and 4.13 +/- 0.31 mum for random fibers, which were significantly thinner than that of film implants 37.7 +/- 0.25 mum (p < 0.001). Additionally, cell infiltration was observed in aligned fibrous scaffolds both in vitro and in vivo, while on random fibers and films, distinct fibrous capsule boundaries were found on the surfaces. These results indicate that aligned electrospun nanofibers may serve as a promising scaffold for tissue engineering by minimizing host response, enhancing tissue-scaffold integration, and eliciting a thinner fibrous capsule. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2009. PMID: 19768795 [PubMed - as supplied by publisher] |
| Effects of cell concentration and collagen concentration on contraction kinetics and mechanical properties in a bone marrow stromal cell-collagen construct.
September 22, 2009 at 7:17 am
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| | Effects of cell concentration and collagen concentration on contraction kinetics and mechanical properties in a bone marrow stromal cell-collagen construct. J Biomed Mater Res A. 2009 Sep 18; Authors: Chieh HF, Sun Y, Liao JD, Su FC, Zhao C, Amadio PC, An KN A cell-collagen construct is commonly used to investigate the phenomenon of wound healing and to estimate the variables for tissue engineering. The purpose of this study was to assess the effects of cell concentration and collagen concentration on the contraction kinetics and mechanical properties of bone marrow stromal cell (BMSC) seeded collagen lattices. To investigate the effects of both variables on the contraction kinetics, the construct contraction was monitored up to 13 days. Incremental stress- relaxation tests were carried out after a 2-week incubation to obtain the stress-strain profiles, which were subsequently assessed in a quasilinear viscoelastic (QLV) model. During contraction, aligned BMSCs were observed first in the interior portion of the ring, followed by the middle portion and finally in the exterior portion. Constructs seeded with a higher initial cell concentration (higher than 1 x 10(5) cells/mL) or lower initial collagen concentration (lower than 2 mg/mL) exhibited faster contraction, higher ultimate stress, and superior elasticity and reduced relaxation behavior (p < 0.05). The cell-collagen model was successfully used to yield information regarding the initial cell concentration and the initial collagen concentration on contraction kinetics and mechanical behavior, which may have possible application in tissue engineering. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2009. PMID: 19768794 [PubMed - as supplied by publisher] |
| Generation of reactive oxygen species from porous silicon microparticles in cell culture medium.
September 22, 2009 at 7:17 am
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| | Generation of reactive oxygen species from porous silicon microparticles in cell culture medium. J Biomed Mater Res A. 2009 Sep 18; Authors: Low SP, Williams KA, Canham LT, Voelcker NH Nanostructured (porous) silicon is a promising biodegradable biomaterial, which is being intensively researched as a tissue engineering scaffold and drug-delivery vehicle. Here, we tested the biocompatibility of non-treated and thermally-oxidized porous silicon particles using an indirect cell viability assay. Initial direct cell culture on porous silicon determined that human lens epithelial cells only poorly adhered to non-treated porous silicon. Using an indirect cell culture assay, we found that non-treated microparticles caused complete cell death, indicating that these particles generated a toxic product in cell culture medium. In contrast, thermally-oxidized microparticles did not reduce cell viability significantly. We found evidence for the generation of reactive oxygen species (ROS) by means of the fluorescent probe 2',7'-dichlorofluorescin. Our results suggest that non-treated porous silicon microparticles produced ROS, which interacted with the components of the cell culture medium, leading to the formation of cytotoxic species. Oxidation of porous silicon microparticles not only mitigated, but also abolished the toxic effects. (c) 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2009. PMID: 19768791 [PubMed - as supplied by publisher] |
| A novel alginate hollow fiber bioreactor process for cellular therapy applications.
September 22, 2009 at 7:17 am
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| | A novel alginate hollow fiber bioreactor process for cellular therapy applications. Biotechnol Prog. 2009 Sep 18; Authors: Hoesli CA, Luu M, Piret JM Gel-matrix culture environments provide tissue engineering scaffolds and cues that guide cell differentiation. For many cellular therapy applications such as for the production of islet-like clusters to treat Type 1 diabetes, the need for large-scale production can be anticipated. The throughput of the commonly used nozzle-based devices for cell encapsulation is limited by the rate of droplet formation to approximately 0.5 L/h. This work describes a novel process for larger-scale batch immobilization of mammalian cells in alginate-filled hollow fiber bioreactors (AHFBRs). A methodology was developed whereby (1) alginate obstruction of the intra-capillary space medium flow was negligible, (2) extra-capillary alginate gelling was complete and (3) 83 +/- 4% of the cells seeded and immobilized were recovered from the bioreactor. Chinese hamster ovary (CHO) cells were used as a model aggregate-forming cell line that grew from mostly single cells to pancreatic islet-sized spheroids in 8 days of AHFBR culture. CHO cell growth and metabolic rates in the AHFBR were comparable to small-scale alginate slab controls. Then, the process was applied successfully to the culture of primary neonatal pancreatic porcine cells, without significant differences in cell viability compared with slab controls. As expected, alginate-immobilized culture in the AHFBR increased the insulin content of these cells compared with suspension culture. The AHFBR process could be refined by adding matrix components or adapted to other reversible gels and cell types, providing a practical means for gel-matrix assisted cultures for cellular therapy. (c) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009. PMID: 19768776 [PubMed - as supplied by publisher] |
| Biological assemblies provide novel templates for the synthesis of hierarchical structures and facilitate cell adhesion.
September 22, 2009 at 7:17 am
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| | Biological assemblies provide novel templates for the synthesis of hierarchical structures and facilitate cell adhesion. Adv Funct Mater. 2008 Dec 22;18(24):3972-3980 Authors: Gajjeraman S, He G, Narayanan K, George A Mechanical mismatch and the lack of interactions between implants and the natural tissue environment are the major drawbacks in bone tissue engineering. Biomaterials mimicking the self-assembly process and the composition of the bone matrix should provide new route for fabricating biomaterials possessing novel osteoconductive and osteoinductive properties for bone repair. In the present study, we employ bio-inspired strategies to design de novo self-assembled chimeric protein hydrogels comprising leucine zipper motifs flanked by dentin matrix protein 1 domain, which was characterized as a mineralization nucleator. Results showed that this chimeric protein could function as a hydroxyapatite nucleator in pseudo-physiological buffer with the formation of highly oriented apatites similar to biogenic bone mineral. It could also function as an inductive substrate for osteoblast adhesion, promote cell surface integrin presentation and clustering, and modulate the formation of focal contacts. Such biomimetic "bottom-up" construction with dual osteoconductive and osteoinductive properties should open new avenues for bone tissue engineering.Mechanical mismatch and the lack of interactions between implants and the natural tissue environment are the major drawbacks in bone tissue engineering. Biomaterials mimicking the self-assembly process and the composition of the bone matrix should provide new route for fabricating biomaterials possessing novel osteoconductive and osteoinductive properties for bone repair. In the present study, we employ bio-inspired strategies to design de novo self-assembled chimeric protein hydrogels comprising leucine zipper motifs flanked by dentin matrix protein 1 domain, which was characterized as a mineralization nucleator. Results showed that this chimeric protein could function as a hydroxyapatite nucleator in pseudo-physiological buffer with the formation of highly oriented apatites similar to biogenic bone mineral. It could also function as an inductive substrate for osteoblast adhesion, promote cell surface integrin presentation and clustering, and modulate the formation of focal contacts. Such biomimetic "bottom-up" construction with dual osteoconductive and osteoinductive properties should open new avenues for bone tissue engineering. PMID: 19768126 [PubMed - as supplied by publisher] |
| Contribution of bone marrow mesenchymal stem cells to porcine hepatocyte culture in vitro.
September 22, 2009 at 7:17 am
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| | Contribution of bone marrow mesenchymal stem cells to porcine hepatocyte culture in vitro. Biochem Cell Biol. 2009 Aug;87(4):595-604 Authors: Gu J, Shi X, Chu X, Zhang Y, Ding Y One of the greatest challenges in the attempt to create functional bioartificial liver designs is the maintenance of porcine hepatocyte differentiated functions in vitro. Co-cultivation of hepatocytes with nonparenchymal cells may be beneficial for optimizing cell functions via mimicry of physiological microenvironment. However, the underlying mechanisms remain to be elucidated. An equal number of freshly isolated porcine hepatocytes and purified bone marrow mesenchymal stem cells (MSCS) was randomly co-cultured and the morphological and functional changes of heterotypic interactions were characterized. Furthermore, contributions of soluble factors involved in the separated co-culture system were evaluated. The purity of the third-passage MSCS and primary hepatocytes was more than 90% and 99%, respectively. Hepatocyte viability was greater than 95%. A rapid attachment and self-organization of three-dimensional hepatocyte spheroids were encouraged, which was due to the supporting MSCS of high motility. The elevated induction of both albumin production and urea synthesis was achieved in co-culture (P < 0.05). Data from semipermeable membrane cultures suggested that interleukin-6 is one of the key stimulators in hepatic functional enhancement. These results demonstrate for the first time that soluble factors have beneficial effects on the preservation of hepatic morphology and functionality in the co-culture of hepatocytes with MSCS in vitro, which could represent a promising tool for tissue engineering, cell biology, and bioartificial liver devices. PMID: 19767823 [PubMed - in process] |
| Neural crest lineage segregation: a blueprint for periodontal regeneration.
September 22, 2009 at 7:17 am
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| | Neural crest lineage segregation: a blueprint for periodontal regeneration. J Dent Res. 2009 Sep;88(9):781-91 Authors: Luan X, Dangaria S, Ito Y, Walker CG, Jin T, Schmidt MK, Galang MT, Druzinsky R During the recent decade, the periodontal attachment apparatus has become one of the premier areas of the body for the development of novel tissue-engineering strategies. In the present review, we describe a developmental biology approach to characterize current concepts in periodontal regeneration and to discuss strategies for future applications in periodontal therapies. To decipher the developmental make-up of the periodontal region, we have followed the path of the migratory neural crest, since it gives rise to periodontal progenitor tissues, which in turn are subjected to the influence of diverse craniofacial extracellular matrices and peptide growth factors. Based on this developmental perspective, we have conducted a systematic analysis of the factors, progenitor cells, and matrices used in current periodontal tissue-engineering approaches. We propose that the developmental history of a tissue is a highly instructive design template for the discovery of novel bioengineering tools and approaches. PMID: 19767574 [PubMed - in process] |
| Focal injection of vancomycin combined with surgical debridement-dermatoplasty in the treatment of pseudo-epitheliomatous granuloma.
September 22, 2009 at 7:17 am
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| | Focal injection of vancomycin combined with surgical debridement-dermatoplasty in the treatment of pseudo-epitheliomatous granuloma. Burns. 2009 Sep 18; Authors: Jiang DY, Fu XB, Zong XL, Chen B, Wang JC, Shan F BACKGROUND: Pseudo-epitheliomatous granuloma (PEG) can occur in some small skin wounds with secondary infections resulting from improper treatments. It is difficult to heal and can easily relapse. OBJECTIVES: This study explores the clinical and pathological characteristics of PEG and effective treatments. PATIENTS AND METHODS: Tissue specimens of PEG obtained from 11 patients (age range: 2-67 years) were sent for microbial examination and histological observation. The local lesions were treated by focal injection of vancomycin combined with surgical debridement-dermatoplasty. RESULTS: The diagnosis of PEG was based on histological examination, which revealed long epithelial peduncle encapsulated granulation tissue-like honeycomb in which more vessels, macrophages, lymphocytes and mast cells and less extracellular matrix were distributed. Bacteria such as Staphylococcus aureus, Bacillus pyocyaneus, ethylene-type Streptococcus, stool Streptococcus and F-citric acid Bacillus were found in the microbial culture of the specimens. They were tolerant to celbenin but sensitive to vancomycin. PEG could be cured by focal application of vancomycin combined with free skin or skin flap after thorough debridement. The relapse of PEG could be prevented by the therapy. CONCLUSION: Focal injection of vancomycin combined with surgical debridement-dermatoplasty is an effective therapy for PEG. PMID: 19767150 [PubMed - as supplied by publisher] |
| The use of dentin matrix scaffold and dental follicle cells for dentin regeneration.
September 22, 2009 at 7:17 am
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| | The use of dentin matrix scaffold and dental follicle cells for dentin regeneration. Biomaterials. 2009 Sep 18; Authors: Guo W, He Y, Zhang X, Lu W, Wang C, Yu H, Liu Y, Li Y, Zhou Y, Zhou J, Zhang M, Deng Z, Jin Y Scaffold and inductive microenvironment are the two most important factors for dentin regeneration. They have been addressed with hydroxyapatite, tricalcium phosphate, polyglycolic acid, calcined bovine bone, and collagen, among other things. However, as of yet, no scaffold and inductive microenvironment combination has been shown to contribute to the regeneration of complete and prefabricated-shaped dentin tissues that include dentin, predentin and odontoblasts. To test the supporting and inductive effects of treated dentin matrix (TDM) on complete and prefabricated-shaped dentin regeneration, dental follicle cells (DFCs) were seeded onto TDM and further incubated for 1 and 2 weeks in vitro and for 2 and 4 weeks in vivo. The results show that in vitro, in addition to dentin sialoprotein (DSP) and dentin matrix protein 1 (DMP1) (regarded as identifying markers of odontoblasts), DFCs induced by TDM expressed osteocalcin, bone sialoprotein, type I collagen, osteopontin, osteonectin and alkaline phosphatase (all expressed by odontoblasts), and that complete and prefabricated-shaped dentin was successfully regenerated. Most importantly, it was found that in vivo TDM supports and induces regeneration of complete and prefabricated-shaped dentin, and regenerated dentin expresses DSP and DMP1, which are identifying dentin markers. Taken together, these results suggest that, for dentin regeneration, TDM is a suitable scaffold and inductive microenvironment and DFCs are a suitable cell type. The combination of TDM and DFCs may constitute a promising approach for future clinical dentin regeneration. PMID: 19767098 [PubMed - as supplied by publisher] |
| Transplantation of human mesenchymal stem cells in a non-autogenous setting for bone regeneration in a rabbit critical size defect model.
September 22, 2009 at 7:17 am
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| | Transplantation of human mesenchymal stem cells in a non-autogenous setting for bone regeneration in a rabbit critical size defect model. Acta Biomater. 2009 Sep 17; Authors: Niemeyer P, Szalay K, Luginbühl R, Südkamp NP, Kasten P Human mesenchymal stem cells (hMSC) represent an attractive cell population for tissue engineering purposes. Furthermore, hMSC are described as immune privileged, non-autogenous application seems possible. The current study examines the regeneration potential of hMSC after xenogenic transplantation compared to autogenous rabbit MSC in a critical-size bone defect. After isolation of hMSC and rabbit MSC were seeded on calcium-deficient hydroxyapatite (CDHA) and transplanted into a radial critical-size defect of New Zealand white rabbits. Defects were filled with either a CDHA scaffold seeded with autogenous rabbit MSC, CDHA seeded with xenogenic hMSC, unseeded CDHA. An empty defect served as control group. Animals were sacrificed after 3 months; evaluation was performed using radiography, micro-computed tomography (muCT) and histology. In addition, a non-destructive 4-point-bending test was performed in order to evaluate biomechanical stiffness. While autogenous MSC seeded on CDHA led to increased healing of critical size bone defects from radiological (mu-CT; p = 0.009) and histological (p = 0.048) perspectives compared to unloaded CDHA, we were not able to demonstrate analogous effects for the xenogenic transplanation of hMSC. The xenogenic treatment group displayed inferior results in all parameters compared to the autogenous MSC treatment group (histology p = 0.041; mu-CTp = 0.006; biomechanical testing p = 0.017). Nevertheless, no local or systemic inflammatory response resulting from xenogenic transplantation was observed. While previous papers suggest use of non-autogenous hMSC cells for tissue engineering purposes, our results show inferior clinical results from transplantation of hMSC in a xenogenic setting compared autogenous MSC. PMID: 19766744 [PubMed - as supplied by publisher] | 
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