| |  | | | | | | | | | | | | | | | |  | | | | | | | | | | | | | | | | | | | | | | | | A Wider Context for Gene Trap Mutagenesis. Methods Enzymol. 2010;477C:271-295 Authors: Brickman JM, Tsakiridis A, To C, Stanford WL Gene trapping is a technology originally developed for the simultaneous identification and mutation of genes by random integration in embryonic stem (ES) cells. While gene trapping was developed before efficient and high-throughput gene targeting, a significant proportion of the publically available mutant ES cell lines and mice were generated through a number of large-scale gene trapping initiatives. Moreover, elements of gene trap vectors continue to be incorporated into gene targeting vectors as a means to increase the efficiency of homologous recombination. Here, we review the current state of gene trapping technology and the applications of specific types of gene trap vector. As a component of this analysis, we consider the behavior of specific vector types both from the perspective of their application and how they can inform our annotation of the mammalian transcriptome. We consider the utility of gene trap vectors as tools for cell-based expression analysis, targeted screening in embryonic differentiation, and for use in cell lines derived from different lineages. PMID: 20699146 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Gelatinized Copper-Capillary Alginate Gel Functions as an Injectable Tissue Scaffolding System for Stem Cell Transplants. J Biomater Sci Polym Ed. 2010 Aug 9; Authors: Willenberg BJ, Zheng T, Meng FW, Meneses JC, Rossignol C, Batich CD, Terada N, Steindler DA, Weiss MD In severe hypoxic-ischemic brain injury, cellular components such as neurons and astrocytes are injured or destroyed along with the supporting extracellular matrix. This presents a challenge to the field of regenerative medicine since the lack of extracellular matrix and supporting structures makes the transplant milieu inhospitable to the transplanted cells. A potential solution to this problem is the use of a biomaterial to provide the extracellular components needed to keep cells localized in cystic brain regions, allowing the cells to form connections and repair lost brain tissue. Ideally, this biomaterial would be combined with stem cells, which have been proven to have therapeutic potentials, and could be delivered via an injection. To study this approach, we derived a hydrogel biomaterial tissue scaffold from oligomeric gelatin and copper-capillary alginate gel (GCCAG). We then demonstrated that our multipotent astrocytic stem cells (MASCs) could be maintained in GCCAG scaffolds for up to 2 weeks in vitro and that the cells retained their multipotency. We next performed a pilot transplant study in which GCCAG was mixed with MASCs and injected into the brain of a neonatal rat pup. After a week in vivo, our results showed that: the GCCAG biomaterial did not cause a significant reactive gliosis; viable cells were retained within the injected scaffolds; and some delivered cells migrated into the surrounding brain tissue. Therefore, GCCAG tissue scaffolds are a promising, novel injectable system for transplantation of stem cells to the brain. PMID: 20699061 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Experimental approaches for the generation of induced pluripotent stem cells. Stem Cell Res Ther. 2010 Aug 10;1(3):26 Authors: Sommer CA, Mostoslavsky G ABSTRACT: Derivation of autologous induced pluripotent stem cells (iPSCs) through direct reprogramming of easily accessible somatic cells holds the potential to transform the field of regenerative medicine. Since Takahashi and Yamanaka's groundbreaking study describing the generation of iPSCs by retroviral-mediated delivery of defined transcription factors, substantial progress has been made to improve both the efficiency and safety of the method. These advances have provided new insights into the molecular mechanisms of reprogramming and promise to accelerate the clinical translation of iPSC technology. Here, we summarize current reprogramming methodologies with a focus on the production of transgene-free or genetically unmanipulated iPSCs and highlight important technical details that ultimately may influence the biological properties of pluripotent stem cells. PMID: 20699015 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Acclimatized induction reveals the multipotency of adult human undifferentiated keratinocytes. Cell Reprogram. 2010 Jun;12(3):283-94 Authors: Han W, Chen M, Li M, Wu Z, Zhao Y, Wang Y, Wang L, Yu L, Fu X Abstract It has been demonstrated that several types of somatic stem cells have the remarkable capacity to differentiate into other types of tissues. However, the promise of keratinocyte stem cells seems slim for generating nonepidermal tissues. Using our recently developed acclimatization induction strategy, we demonstrate the multipotency of adult human undifferentiated keratinocytes (UKs). The UKs were isolated from the basal layer of adult human foreskin and cultured in Epilife medium, which allows for the growth of only keratin-positive keratinocytes, promotes high proliferation of UKs, and prevents their differentiation. Induction of the UKs by either serum or lineage-committed medium only produce differentiated epidermal cells. Hence, serum or lineage-committed medium was added to Epilife to acclimate UKs to differentiate to other cell types. Unexpectedly, serum acclimatization can induce UKs to produce a large number of smooth muscle cells and fewer of adipocytes and neurocytes within 3 weeks. In contrast, except for the terminally differentiated epidermal cells, committed acclimatization can induce UKs to differentiate exclusively into the adipocytic, myogenic, or neurogenic lineages. These data indicate that human UKs represent a novel multipotent adult stem cell, and suggest that they may provide an accessible, therapeutically promising cell source for regenerative medicine. PMID: 20698770 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [Biomedical engineering supports surgical planning and interventions.] Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz. 2010 Aug;53(8):791-800 Authors: Dickhaus H, Metzner R Fundamental changes were achieved with the introduction of minimally invasive surgery. In this context, innovations in microtechnology played a significant role in the deployment of new tools. Developments for further integration are still ongoing. Furthermore, decisive progress was made by the timely provision of individual patient data prior to surgery. These comprise imaging data, electrophysiological or functional recordings, and synthetic data gained by modeling and simulation of anatomical or physiological conditions. Aside from the technical aspects of supporting surgery, effective quality management and optimized workflow are essential for therapeutic success. The vision of autonomously operating robots has been dropped in favor of permanently conducted and supervised interventions with the support of intelligent tools for the surgeon. Recent advances in reconstruction and transplantation surgery by tissue engineering and molecular biology are only the beginning of new promising concepts. PMID: 20700778 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Contact models of repaired articular surfaces: influence of loading conditions and the superficial tangential zone. Biomech Model Mechanobiol. 2010 Aug 11; Authors: Owen JR, Wayne JS The superficial tangential zone (STZ) plays a significant role in normal articular cartilage's ability to support loads and retain fluids. To date, tissue engineering efforts have not replicated normal STZ function in cartilage repairs. This finite element study examined the STZ's role in normal and repaired articular surfaces under different contact conditions. Contact area and pressure distributions were allowed to change with time, tension-compression nonlinearity modeled collagen behavior in the STZ, and nonlinear geometry was incorporated to accommodate finite deformation. Responses to loading via impermeable and permeable rigid surfaces were compared to loading via normal cartilage, a more physiologic condition, anticipating the two rigid loading surfaces would bracket that of normal. For models loaded by normal cartilage, an STZ placed over the inferior repair region reduced the short-term axial compression of the articular surface by 15%, when compared to a repair without an STZ. Covering the repair with a normal STZ shifted the flow patterns and strain levels back toward that of normal cartilage. Additionally, reductions in von Mises stress (21%) and an increase in fluid pressure (13%) occurred in repair tissue under the STZ. This continues to show that STZ properties of sufficient quality are likely critical for the survival of transplanted constructs in vivo. However, response to loading via normal cartilage did not always fall within ranges predicted by the rigid surfaces. Use of more physiologic contact models is recommended for more accurate investigations into properties critical to the success of repair tissues. PMID: 20700624 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cell Therapy in Tendon Disorders: What Is the Current Evidence? Am J Sports Med. 2010 Aug 10; Authors: Obaid H, Connell D BACKGROUND: Various types of tissue-derived cells are being experimented with for the treatment of tendinopathy, tendon repair, and use in tissue engineering. PURPOSE: The aim of this systematic review is to explore the current evidence with a view to evaluate the potential of this therapeutic intervention. STUDY DESIGN: Systematic review. METHODS: A review of the literature was conducted using PubMed. Search criteria included keywords "tendinopathy," "tendinitis," "tendinosis," "epicondylitis," "stem cell," and "cell therapy." Articles not written in English language were excluded. RESULTS: A total number of 379 articles were identified and a critical appraisal of the relevant articles was undertaken, which encompassed human and animal research. The review included articles related to various tissue-derived cells such as tendon progenitors, adipose tissue, synovium, muscle, bone marrow, and skin. The utility of cell therapy in tissue engineering and rotator cuff repair was also assessed. CONCLUSION: With the limitation of the available evidence, the literature suggests that cell therapy is applicable and may be effective for the treatment of tendinopathy. However, further research into the precise biological mechanisms, long-term implications, and cost-effectiveness is needed. PMID: 20699425 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Expansion and characterization of human embryonic stem cell-derived osteoblast-like cells. Cell Reprogram. 2010 Aug;12(4):377-89 Authors: Arpornmaeklong P, Wang Z, Pressler MJ, Brown SE, Krebsbach PH Abstract Human embryonic stem cells (hESCs) have the potential to serve as a repository of cells for the replacement of damaged or diseased tissues and organs. However, to use hESCs in clinically relevant scenarios, a large number of cells are likely to be required. The aim of this study was to demonstrate an alternative cell culture method to increase the quantity of osteoblast-like cells directly derived from hESCs (hESCs-OS). Undifferentiated hESCs were directly cultivated and serially passaged in osteogenic medium (hESC-OS), and exhibited similar expression patterns of osteoblast-related genes to osteoblast-like cells derived from mesenchymal stem cells derived from hESCs (hESCs-MSCs-OS) and human bone marrow stromal cells (hBMSCs-OS). In comparison to hESCs-MSCs-OS, the hESCs-OS required a shorter expansion time to generate a homogenous population of osteoblast-like cells that did not contain contaminating undifferentiated hESCs. Identification of human specific nuclear antigen (HuNu) in the newly formed bone in calvarial defects verified the role of the transplanted hESCs-OS as active bone forming cells in vivo. Taken together, this study suggests that osteoblast-like cells directly derived from hESCs have the potential to serve as an alternative source of osteoprogenitors for bone tissue engineering strategies. PMID: 20698777 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Enhanced treatment of articular cartilage defect of the knee by intra-articular injection of Bcl-xL-engineered mesenchymal stem cells in rabbit model. J Tissue Eng Regen Med. 2010 Feb;4(2):105-14 Authors: Hu B, Ren JL, Zhang JR, Ma Q, Liu YP, Mao TQ Direct intra-articular injection of mesenchymal stem cells (MSCs) has been proposed as a potential cell therapy for cartilage defects. This cell therapy relies on the survival of the implanted MSCs. However, the arduous local environment may limit cell viability after implantation, which would restrict the cells' regenerative capacity. Thus, it is necessary to reinforce the implanted cells against the unfavourable microenvironment in order to improve the efficacy of cell therapy. We examined whether the transduction of an anti-apoptotic protein, Bcl-xL, into MSCs could prevent cell death and improve the implantation efficiency of MSCs in a rabbit model. Our current findings demonstrate that the group treated with Bcl-xL-engineered MSCs could improve cartilage healing both morphologically and histologically when compared with the controls. These results suggest that intra-articular injection of Bcl-xL-engineered MSCs is a potential non-invasive therapeutic method for effectively treating cartilage defects of the knee. PMID: 19927304 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cell Therapy in Tendon Disorders: What Is the Current Evidence? Am J Sports Med. 2010 Aug 10; Authors: Obaid H, Connell D BACKGROUND: Various types of tissue-derived cells are being experimented with for the treatment of tendinopathy, tendon repair, and use in tissue engineering. PURPOSE: The aim of this systematic review is to explore the current evidence with a view to evaluate the potential of this therapeutic intervention. STUDY DESIGN: Systematic review. METHODS: A review of the literature was conducted using PubMed. Search criteria included keywords "tendinopathy," "tendinitis," "tendinosis," "epicondylitis," "stem cell," and "cell therapy." Articles not written in English language were excluded. RESULTS: A total number of 379 articles were identified and a critical appraisal of the relevant articles was undertaken, which encompassed human and animal research. The review included articles related to various tissue-derived cells such as tendon progenitors, adipose tissue, synovium, muscle, bone marrow, and skin. The utility of cell therapy in tissue engineering and rotator cuff repair was also assessed. CONCLUSION: With the limitation of the available evidence, the literature suggests that cell therapy is applicable and may be effective for the treatment of tendinopathy. However, further research into the precise biological mechanisms, long-term implications, and cost-effectiveness is needed. PMID: 20699425 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Generation and characterization of neurospheres from canine adipose tissue-derived stromal cells. Cell Reprogram. 2010 Aug;12(4):417-25 Authors: Lim JH, Boozer L, Mariani CL, Piedrahita JA, Olby NJ Abstract Adipose tissue-derived stromal cells (ADSCs) have been identified as a powerful stem cell source for cellular transplantation therapy. The dog is increasingly used as a model of human neurological disease; however, few studies have reported induction of canine ADSCs to neural lineages. We characterized canine ADSCs and investigated whether they could be induced to differentiate into neural lineages. Subcutaneous adipose tissue collected from the dorsal epaxial region of adult dogs aged from 1 to 6 years was cultured to produce ADSCs that were then induced to neural lineages. RT-PCR, flow cytometry, and immunocytochemistry were performed to characterize these cell populations. Morphologically fibroblast-like ADSCs were isolated and had similar characteristics to mesenchymal stem cells. Under neurogenic conditions containing basic fibroblast growth factor and epidermal growth factor, ADSCs formed spherical cellular aggregates that resembled neurospheres. RT-PCR confirmed expression of Sox2 and CD90 by these aggregates. Expression of neural stem/progenitor markers (Nestin, Sox2, Vimentin) and neural lineage markers (A2B5, GFAP, Tuj1) was shown on immunocytochemistry. After differentiation, 60% of the cells were Tuj1 positive. In conclusion, we isolated and generated neural progenitor cells from canine ADSCs. ADSCs have potential for future autologous cell transplantation therapy for neurological disorders. PMID: 20698780 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adipose tissue-derived stem cells from humans and mice differ in proliferative capacity and genome stability in long-term cultures. Stem Cells Dev. 2010 Aug 10; Authors: Danoviz ME, Bassaneze V, Nakamuta JS, Santos-Junior GR, Saint-Clair D, Bajgelman MC, Fae KC, Kalil JE, Miyakawa AA, Krieger JE Adipose tissue-derived stem cells (ASCs) are among the more attractive adult stem cell options for potential therapeutic applications. Here, we studied and compared basic biological characteristics of ASCs isolated from humans (hASCs) and mice (mASCs), maintained in identical culture conditions that must be examined prior to considering further potential clinical applications. hASCs and mASCs were compared for immunophenotype, differentiation potential, cell growth characteristics, senescence, nuclear morphology, and DNA content. Although both strains of ASCs displayed a similar immunophenotype, the percentage of CD73+ cells was markedly lower and CD31+ higher in mASC than in hASC cultures. The mean population doubling time was 98.08 +/- 6.15 hours for hASCs and 52.58 +/- 3.74 hours for mASCs. The frequency of nuclear aberrations was noticeably lower in hASCs than in mASCs regardless of the passage number. Moreover, as the cells went through several in vitro passages, mASCs showed changes in DNA content and cell cycle kinetics (frequency of hypodiploid, G0/G1, G2/M and hyperdiploid cells), while all of these parameters remained constant in hASCs. Collectively, these results suggest that mASCs display higher proliferative capacity and are more unstable than hASCs in long-term cultures. These results underscore the need to consider specificities among model systems that may influence outcomes when designing potential human applications. PMID: 20698764 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Transplantation of human adipose tissue-derived multilineage progenitor cells reduces serum cholesterol in hyperlipidemic Watanabe rabbits. Tissue Eng Part C Methods. 2010 Aug 10; Authors: Okura H, Saga A, Fumimoto Y, Soeda M, Moriyama M, Moriyama H, Nagai K, Lee CM, Yamashita S, Ichinose A, Hayakawa T, Matsuyama A Familial hypercholesterolemia (FH) is an autosomal codominant disease characterized by high concentrations of pro-atherogenic lipoproteins and premature atherosclerosis secondary to low density lipoprotein (LDL) receptor deficiency. We examined a novel cell therapy strategy for the treatment of FH in the Watanabe heritable hyperlipidemic (WHHL) rabbit, an animal model for homozygous FH. We delivered human adipose tissue-derived multilineage progenitor cells (hADMPCs) via portal vein and followed by immunosuppressive regimen to avoid xenogenic rejection. Transplantation of hADMPCs resulted in significant reductions in total cholesterol, and the reductions were observed within 4 weeks and maintained for 12 weeks. 125I-LDL turnover study showed that the rate of LDL clearance was significantly higher in the WHHL rabbits with transplanted hADMPCs than those without transplanted. After transplantation hADMPCs were localized in the portal triad, subsequently integrated into the hepatic parenchyma. The integrated cells expressed human albumin, human alpha-1-antitrypsin, human Factor IX, human LDL receptors and human bile salt export pump, indicating that the transplanted hADMPCs resided, survived and showed hepatocytic differentiation in vivo and lowered serum cholesterol in the WHHL rabbits. These results suggested that hADMPCs transplantation could correct the metabolic defects and be a novel therapy for inherited liver diseases. PMID: 20698754 [PubMed - as supplied by publisher] | | | | | | | | | | |  |
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