|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | The "Latest California Budget" item earlier today incorrectly indicated that CIRM had funds through about June. The correct date is about June of 2012. | | | | | | | | | | | | | | | | | | | | | | | | California Gov. Jerry Brown is proposing a "dramatically" reduced sale of state bonds, which are the only real source of income for the California stem cell agency, during the coming fiscal year.
His plan was contained in what is the known as the May revise of the governor's budget. Randall Jensen(no relation to this writer) wrote today in The Bond Buyer, a newswpaper devoted to public finance, | | | | | | | | | | | | | | | | | | | | | | | | | The Vascular Adventitia : Its Role in the Arterial Injury Response. Vasc Endovascular Surg. 2011 May 13; Authors: Havelka GE, Kibbe MR The belief that the adventitia serves only a structural purpose has changed over the last decade. Studies have begun to elucidate the role the adventitia plays in the arterial response to injury. The adventitial fibroblast plays an integral part in the development of neointimal hyperplasia. Adiponectin, an adipokine produced from periadventitial adipose tissue, exhibits numerous vasoprotective properties. Stem cells arise, in part, from the adventitia, and stem cell recruitment into the adventitia from the vasa vasorum has been shown to be important in the development of neointimal hyperplasia. The exact role the vasa vasorum plays in neointimal growth is poorly understood and different studies endorse conflicting viewpoints. Thus, understanding the nuances of adventitial pathophysiology will allow us to better appreciate the mechanisms behind the pathology of neointimal hyperplasia. This review will summarize recent findings on the active role the adventitia plays toward the development of neointimal hyperplasia. PMID: 21571779 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Chemerin, a novel PPAR{gamma} target gene that promotes mesenchymal stem cell adipogenesis. J Biol Chem. 2011 May 14; Authors: Muruganandan S, Parlee SD, Rourke JL, Ernst MC, Goralski KB, Sinal CJ Chemerin is an adipocyte-secreted protein that regulates adipogenesis and the metabolic function of mature adipocytes via activation of chemokine-like receptor 1 (CMKLR1). Herein we report the interaction of peroxisome proliferator-activated receptor gamma (PPARγ) and chemerin in the context of adipogenesis. Knockdown of chemerin or CMKLR1 expression or antibody neutralization of secreted chemerin protein arrested adipogenic clonal expansion of bone marrow mesenchymal stem cells (BMSCs) by inducing a loss of G2/M cyclins (cyclin A2/B2) but not the G1/S cyclin D2. Forced expression of PPARγ in BMSCs did not completely rescue this loss of clonal expansion and adipogenesis following chemerin or CMKLR1 knockdown. However, forced expression and/or activation of PPARγ in BMSCs as well as non-adipogenic cell types such as NIH-3T3 embryonic fibroblasts and MCA38 colon carcinoma cells significantly induced chemerin expression and secretion. Sequence analysis revealed a putative PPARγ response sequence (PPRE) within the chemerin promoter. This PPRE was able to confer PPARγ responsiveness on a heterologous promoter and mutation of this sequence abolished activation of the chemerin promoter by PPARγ. Chromatin immunoprecipitation confirmed the direct association of PPARγ with this PPRE. Treatment of mice with rosiglitazone elevated chemerin mRNA levels in adipose and bone marrow coincident with an increase in circulating chemerin levels. Together, these findings support a fundamental role for chemerin/CMKLR1 signaling in clonal expansion during adipocyte differentiation as well as a role for PPARγ in regulating chemerin expression. PMID: 21572083 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Different populations and sources of human mesenchymal stem cells (MSC): A comparison of adult and neonatal tissue-derived MSC. Cell Commun Signal. 2011 May 14;9(1):12 Authors: Hass R, Kasper C, Bohm S, Jacobs R ABSTRACT: The mesenchymal stroma harbors an important population of cells that possess stem cell-like characteristics including self renewal and differentiation capacities and can be derived from a variety of different sources. These multipotent mesenchymal stem cells (MSC) can be found in nearly all tissues and are mostly located in perivascular niches. MSC have migratory abilities and can secrete protective factors and act as a primary matrix for tissue regeneration during inflammation, tissue injuries and certain cancers. These functions underlie the important physiological roles of MSC and underscore a significant potential for the clinical use of distinct populations from the various tissues. MSC derived from different adult (adipose tissue, peripheral blood, bone marrow) and neonatal tissues (particular parts of the placenta and umbilical cord) are therefore compared in this mini-review with respect to their cell biological properties, surface marker expression and proliferative capacities. In addition, several MSC functions including in vitro and in vivo differentiation capacities within a variety of lineages and immune-modulatory properties are highlighted. Differences in the extracellular milieu such as the presence of interacting neighbouring cell populations, exposure to proteases or a hypoxic microenvironment contribute to functional developments within MSC populations originating from different tissues, and intracellular conditions such as the expression levels of certain micro RNAs can additionally balance MSC function and fate. PMID: 21569606 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Adipogenic Potential of Adipose Stem Cell Subpopulations. Plast Reconstr Surg. 2011 May 12; Authors: Li H, Zimmerlin L, Marra KG, Donnenberg VS, Donnenberg AD, Rubin JP BACKGROUND:: Adipose stem cells (ASCs) represent a heterogenous population. Understanding the functional characteristics of subpopulations will be useful in developing ASC-based therapies for regenerative medicine applications. The aim of this study was to define distinct populations within the stromal vascular fraction based on surface marker expression, and evaluate the ability of each cell type to differentiate to mature adipocytes. METHODS:: Subcutaneous whole adipose tissue was obtained by abdominoplasty from human patients. The stromal vascular fraction was separated and four cell populations were isolated by flow cytometry and studied. Candidate perivascular cells (pericytes), were defined as CD146+/CD31-/CD34-. Two CD31+ endothelial populations were detected and differentiated by CD34 expression. These were tentatively designated as mature endothelial (CD 31+/CD34-), and immature endothelial (CD31+/CD34+). Both endothelial populations were heterogeneous with respect to CD146. The CD31-/CD34+ fraction (preadipocyte candidate) was also CD90+, but lacked CD146 expression. RESULTS:: Proliferation was greatest in the CD31-/CD34+ group and slowest in the CD146+ group. Expression of adipogenic genes, PPARγ and Fatty Acid Binding Protein 4(FABP4), were significantly higher in the CD31-/CD34+ group compared with all other populations after in vitro adipogenic differentiation. This group also demonstrated the highest proportion of Adipored lipid staining. CONCLUSIONS:: We have isolated four distinct stromal populations from human adult adipose tissue and characterized their adipogenic potential. Of these four populations, the CD31-/CD34+ group is the most prevalent and has the greatest potential for adipogenic differentiation. This cell type appears to hold the most promise for adipose tissue engineering. PMID: 21572381 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | Stephen Juelsgaard (Photo Iowa State)
A former, longtime Genentech executive yesterday was named to the 29-member board of the $3 billion California stem cell agency.
Stephen Juelsgaard of Woodside, Ca., was appointed by California Lt. Gov. Gavin Newsom to replace Ed Penhoet, a co-founder of Chiron. Penhoet had sat on the board since the agency's inception in 2004. He was vice chairman at one | | | | | | | | | | | | | | | | | | | | | | | | | Impaired function of bone marrow-derived endothelial progenitor cells in murine liver fibrosis. Biosci Trends. 2011 Apr;5(2):77-82 Authors: Shirakura K, Masuda H, Kwon SM, Obi S, Ito R, Shizuno T, Kurihara Y, Mine T, Asahara T Liver fibrosis (LF) caused by chronic liver damage has been considered as an irreversible disease. As alternative therapy for liver transplantation, there are high expectations for regenerative medicine of the liver. Bone marrow (BM)- or peripheral blood-derived stem cells, including endothelial progenitor cells (EPCs), have recently been used to treat liver cirrhosis. We investigated the biology of BM-derived EPC in a mouse model of LF. C57BL/6J mice were subcutaneously injected with carbon tetrachloride (CCl<sub>4</sub>) every 3 days for 90 days. Sacrificed 2 days after final injection, whole blood (WB) was collected for isolation of mononuclear cells (MNCs) and biochemical examination. Assessments of EPC in the peripheral blood and BM were performed by flow cytometry and EPC colonyforming assay, respectively, using purified MNCs and BM c-KIT<sup>+</sup>, Sca-1<sup>+</sup>, and Lin<sup>-</sup> (KSL) cells. Liver tissues underwent histological analysis with hematoxylin/eosin/Azan staining, and spleens were excised and weighed. CCl<sub>4</sub>-treated mice exhibited histologically bridging fibrosis, pseudolobular formation, and splenomegaly, indicating successful induction of LF. The frequency of definitive EPC-colony-forming-units (CFU) as well as total EPC-CFU at the equivalent cell number of 500 BM-KSL cells decreased significantly (p < 0.0001) in LF mice compared with control mice; no significant changes in primitive EPC-CFU occurred in LF mice. The frequency of WB-MNCs of definitive EPC-CFU decreased significantly (p < 0.01) in LF mice compared with control mice. Together, these findings indicated the existence of impaired EPC function and differentiation in BM-derived EPCs in LF mice and might be related to clinical LF. PMID: 21572251 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Sonic hedgehog signaling is decoded by calcium spike activity in the developing spinal cord. Proc Natl Acad Sci U S A. 2011 Mar 15;108(11):4482-7 Authors: Belgacem YH, Borodinsky LN Evolutionarily conserved hedgehog proteins orchestrate the patterning of embryonic tissues, and dysfunctions in their signaling can lead to tumorigenesis. In vertebrates, Sonic hedgehog (Shh) is essential for nervous system development, but the mechanisms underlying its action remain unclear. Early electrical activity is another developmental cue important for proliferation, migration, and differentiation of neurons. Here we demonstrate the interplay between Shh signaling and Ca(2+) dynamics in the developing spinal cord. Ca(2+) imaging of embryonic spinal cells shows that Shh acutely increases Ca(2+) spike activity through activation of the Shh coreceptor Smoothened (Smo) in neurons. Smo recruits a heterotrimeric GTP-binding protein-dependent pathway and engages both intracellular Ca(2+) stores and Ca(2+) influx. The dynamics of this signaling are manifested in synchronous Ca(2+) spikes and inositol triphosphate transients apparent at the neuronal primary cilium. Interaction of Shh and electrical activity modulates neurotransmitter phenotype expression in spinal neurons. These results indicate that electrical activity and second-messenger signaling mediate Shh action in embryonic spinal neurons. PMID: 21368195 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Neural crest regulates myogenesis through the transient activation of NOTCH. Nature. 2011 May 15; Authors: Rios AC, Serralbo O, Salgado D, Marcelle C How dynamic signalling and extensive tissue rearrangements interact to generate complex patterns and shapes during embryogenesis is poorly understood. Here we characterize the signalling events taking place during early morphogenesis of chick skeletal muscles. We show that muscle progenitors present in somites require the transient activation of NOTCH signalling to undergo terminal differentiation. The NOTCH ligand Delta1 is expressed in a mosaic pattern in neural crest cells that migrate past the somites. Gain and loss of Delta1 function in neural crest modifies NOTCH signalling in somites, which results in delayed or premature myogenesis. Our results indicate that the neural crest regulates early muscle formation by a unique mechanism that relies on the migration of Delta1-expressing neural crest cells to trigger the transient activation of NOTCH signalling in selected muscle progenitors. This dynamic signalling guarantees a balanced and progressive differentiation of the muscle progenitor pool. PMID: 21572437 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Chemical and physical properties of regenerative medicine materials controlling stem cell fate. Ann Med. 2011 May 13; Authors: Kaivosoja E, Barreto G, Levón K, Virtanen S, Ainola M, Konttinen YT Abstract Regenerative medicine is a multidisciplinary field utilizing the potential of stem cells and the regenerative capability of the body to restore, maintain, or enhance tissue and organ functions. Stem cells are unspecialized cells that can self-renew but also differentiate into several somatic cells when subjected the appropriate environmental cues. The ability to reliably direct stem cell fate would provide tremendous potential for basic research and clinical therapies. Proper tissue function and regeneration rely on the spatial and temporal control of biophysical and biochemical cues, including soluble molecules, cell-cell contacts, cell-extracellular matrix contacts, and physical forces. The mechanisms involved remain poorly understood. This review focuses on the stem cell-extracellular matrix interactions by summarizing the observations of the effects of material variables (such as overall architecture, surface topography, charge, ζ-potential, surface energy, and elastic modulus) on the stem cell fate. It also deals with the mechanisms underlying the effects of these extrinsic, material variables. Insight in the environmental interactions of the stem cells is crucial for the development of new material-based approaches for cell culture experiments and future experimental and clinical regenerative medicine applications. PMID: 21568670 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Outcome of unrelated umbilical cord blood transplantation in 88 patients with primary immunodeficiency in Japan. Br J Haematol. 2011 May 14; Authors: Morio T, Atsuta Y, Tomizawa D, Nagamura-Inoue T, Kato K, Ariga T, Kawa K, Koike K, Tauchi H, Kajiwara M, Hara T, Kato S, We report the results of umbilical cord blood transplantation (UCBT) performed in 88 patients with primary immunodeficiency (PID) between 1998 and 2008 in Japan; severe combined immunodeficiency (SCID, n = 40), Wiskott-Aldrich syndrome (WAS, n = 23), chronic granulomatous disease (n = 7), severe congenital neutropaenia (SCN, n = 5) and other immunodeficiencies (n = 13). Five-year overall survival (5-year OS) for all patients was 69% [95% confidence interval (CI), 57-78%], and was 71% and 82% for SCID and WAS, respectively. The main cause of death before day 100 was infection (17/19), while that after day 100 was graft-versus-host disease (GVHD) (5/7). Using multivariate analyses, pre-transplant infection, no conditioning, ≥2 human leucocyte antigen (HLA) mismatches or diagnosis other than SCID, SCN or WAS were all associated with poor prognosis. Reduced-intensity conditioning was associated with decreased overall mortality compared with myeloablative therapy. The cumulative incidence of grade 2-4 acute GVHD at day 100 was 28% (95% CI, 19-38%), and that of chronic GVHD at day 180 was 13% (95% CI, 7-23%). We conclude that UCBT should be considered for PID patients without an HLA-matched sibling. The control of pre-transplant infection and selection of HLA-matched donors will lead to a better outcome. PMID: 21569009 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Hedgehog-responsive candidate cell of origin for diffuse intrinsic pontine glioma. Proc Natl Acad Sci U S A. 2011 Mar 15;108(11):4453-8 Authors: Monje M, Mitra SS, Freret ME, Raveh TB, Kim J, Masek M, Attema JL, Li G, Haddix T, Edwards MS, Fisher PG, Weissman IL, Rowitch DH, Vogel H, Wong AJ, Beachy PA Diffuse intrinsic pontine gliomas (DIPGs) are highly aggressive tumors of childhood that are almost universally fatal. Our understanding of this devastating cancer is limited by a dearth of available tissue for study and by the lack of a faithful animal model. Intriguingly, DIPGs are restricted to the ventral pons and occur during a narrow window of middle childhood, suggesting dysregulation of a postnatal neurodevelopmental process. Here, we report the identification of a previously undescribed population of immunophenotypic neural precursor cells in the human and murine brainstem whose temporal and spatial distributions correlate closely with the incidence of DIPG and highlight a candidate cell of origin. Using early postmortem DIPG tumor tissue, we have established in vitro and xenograft models and find that the Hedgehog (Hh) signaling pathway implicated in many developmental and oncogenic processes is active in DIPG tumor cells. Modulation of Hh pathway activity has functional consequences for DIPG self-renewal capacity in neurosphere culture. The Hh pathway also appears to be active in normal ventral pontine precursor-like cells of the mouse, and unregulated pathway activity results in hypertrophy of the ventral pons. Together, these findings provide a foundation for understanding the cellular and molecular origins of DIPG, and suggest that the Hh pathway represents a potential therapeutic target in this devastating pediatric tumor. PMID: 21368213 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Murine Tissue-Engineered Stomach Demonstrates Epithelial Differentiation. J Surg Res. 2011 Apr 20; Authors: Speer AL, Sala FG, Matthews JA, Grikscheit TC BACKGROUND: Gastric cancer remains the second largest cause of cancer-related mortality worldwide. Postgastrectomy morbidity is considerable and quality of life is poor. Tissue-engineered stomach is a potential replacement solution to restore adequate food reservoir and gastric physiology. In this study, we performed a detailed investigation of the development of tissue-engineered stomach in a mouse model, specifically evaluating epithelial differentiation, proliferation, and the presence of putative stem cell markers. MATERIALS AND METHODS: Organoid units were isolated from <3 wk-old mouse glandular stomach and seeded onto biodegradable scaffolds. The constructs were implanted into the omentum of adult mice. Implants were harvested at designated time points and analyzed with histology and immunohistochemistry. RESULTS: Tissue-engineered stomach grows as an expanding sphere with a simple columnar epithelium organized into gastric glands and an adjacent muscularis. The regenerated gastric epithelium demonstrates differentiation of all four cell types: mucous, enteroendocrine, chief, and parietal cells. Tissue-engineered stomach epithelium proliferates at a rate comparable to native glandular stomach and expresses two putative stem cell markers: DCAMKL-1 and Lgr5. CONCLUSIONS: This study demonstrates the successful generation of tissue-engineered stomach in a mouse model for the first time. Regenerated gastric epithelium is able to appropriately proliferate and differentiate. The generation of murine tissue-engineered stomach is a necessary advance as it provides the transgenic tools required to investigate the molecular and cellular mechanisms of this regenerative process. Delineating the mechanism of how tissue-engineered stomach develops in vivo is an important precursor to its use as a human stomach replacement therapy. PMID: 21571313 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Adipogenic Potential of Adipose Stem Cell Subpopulations. Plast Reconstr Surg. 2011 May 12; Authors: Li H, Zimmerlin L, Marra KG, Donnenberg VS, Donnenberg AD, Rubin JP BACKGROUND:: Adipose stem cells (ASCs) represent a heterogenous population. Understanding the functional characteristics of subpopulations will be useful in developing ASC-based therapies for regenerative medicine applications. The aim of this study was to define distinct populations within the stromal vascular fraction based on surface marker expression, and evaluate the ability of each cell type to differentiate to mature adipocytes. METHODS:: Subcutaneous whole adipose tissue was obtained by abdominoplasty from human patients. The stromal vascular fraction was separated and four cell populations were isolated by flow cytometry and studied. Candidate perivascular cells (pericytes), were defined as CD146+/CD31-/CD34-. Two CD31+ endothelial populations were detected and differentiated by CD34 expression. These were tentatively designated as mature endothelial (CD 31+/CD34-), and immature endothelial (CD31+/CD34+). Both endothelial populations were heterogeneous with respect to CD146. The CD31-/CD34+ fraction (preadipocyte candidate) was also CD90+, but lacked CD146 expression. RESULTS:: Proliferation was greatest in the CD31-/CD34+ group and slowest in the CD146+ group. Expression of adipogenic genes, PPARγ and Fatty Acid Binding Protein 4(FABP4), were significantly higher in the CD31-/CD34+ group compared with all other populations after in vitro adipogenic differentiation. This group also demonstrated the highest proportion of Adipored lipid staining. CONCLUSIONS:: We have isolated four distinct stromal populations from human adult adipose tissue and characterized their adipogenic potential. Of these four populations, the CD31-/CD34+ group is the most prevalent and has the greatest potential for adipogenic differentiation. This cell type appears to hold the most promise for adipose tissue engineering. PMID: 21572381 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Treatment of long bone defects and non-unions: from research to clinical practice. Cell Tissue Res. 2011 May 17; Authors: Berner A, Reichert JC, Müller MB, Zellner J, Pfeifer C, Dienstknecht T, Nerlich M, Sommerville S, Dickinson IC, Schütz MA, Füchtmeier B The treatment of long bone defects and non-unions is still a major clinical and socio-economical problem. In addition to the non-operative therapeutic options, such as the application of various forms of electricity, extracorporeal shock wave therapy and ultrasound therapy, which are still in clinical use, several operative treatment methods are available. No consensus guidelines are available and the treatments of such defects differ greatly. Therefore, clinicians and researchers are presently investigating ways to treat large bone defects based on tissue engineering approaches. Tissue engineering strategies for bone regeneration seem to be a promising option in regenerative medicine. Several in vitro and in vivo studies in small and large animal models have been conducted to establish the efficiency of various tissue engineering approaches. Neverthelsss, the literature still lacks controlled studies that compare the different clinical treatment strategies currently in use. However, based on the results obtained so far in diverse animal studies, bone tissue engineering approaches need further validation in more clinically relevant animal models and in clinical pilot studies for the translation of bone tissue engineering approaches into clinical practice. PMID: 21574059 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Ex vivo generation of a highly potent population of circulating angiogenic cells using a collagen matrix. J Mol Cell Cardiol. 2011 May 4; Authors: Kuraitis D, Hou C, Zhang Y, Vulesevic B, Sofrenovic T, McKee D, Sharif Z, Ruel M, Suuronen EJ Biomaterials that have the ability to augment angiogenesis are highly sought-after for applications in regenerative medicine, particularly for revascularization of ischemic and infarcted tissue. We evaluated the culture of human circulating angiogenic cells (CAC) on collagen type I-based matrices, and compared this to traditional selective-adhesion cultures on fibronectin. Culture on a collagen matrix supported the proliferation of CD133(+) and CD34(+)CD133(+) CACs. When subjected to serum starvation, the matrix conferred a resistance to cell death for CD34(+) and CD133(+) progenitors and increased phosphorylation of Akt. After 4days of culture, phenotypically enriched populations of endothelial cells (CD31(+)CD144(+)) and progenitor cells (CD34(+)CD133(+)) emerged. Culture on matrix upregulated the phosphorylation and activation of ERK1/2 pathway members, and matrix-cultured cells also had an enhanced functional capacity for adhesion and invasion. These functional improvements were abrogated when cultured in the presence of ERK inhibitors. The formation of vessel-like structures in an angiogenesis assay was augmented with matrix-cultured cells, which were also more likely to physically associate with such structures compared to CACs taken from culture on fibronectin. In vivo, treatment with matrix-cultured cells increased the size and density of arterioles, and was superior at restoring perfusion in a mouse model of hindlimb ischemia, compared to fibronectin-cultured cell treatment. This work suggests that a collagen-based matrix, as a novel substrate for CAC culture, possesses the ability to enrich endothelial and angiogenic populations and lead to clinically relevant functional enhancements. PMID: 21569777 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Immunogenicity of induced pluripotent stem cells. Nature. 2011 May 13; Authors: Zhao T, Zhang ZN, Rong Z, Xu Y Induced pluripotent stem cells (iPSCs), reprogrammed from somatic cells with defined factors, hold great promise for regenerative medicine as the renewable source of autologous cells. Whereas it has been generally assumed that these autologous cells should be immune-tolerated by the recipient from whom the iPSCs are derived, their immunogenicity has not been vigorously examined. We show here that, whereas embryonic stem cells (ESCs) derived from inbred C57BL/6 (B6) mice can efficiently form teratomas in B6 mice without any evident immune rejection, the allogeneic ESCs from 129/SvJ mice fail to form teratomas in B6 mice due to rapid rejection by recipients. B6 mouse embryonic fibroblasts (MEFs) were reprogrammed into iPSCs by either retroviral approach (ViPSCs) or a novel episomal approach (EiPSCs) that causes no genomic integration. In contrast to B6 ESCs, teratomas formed by B6 ViPSCs were mostly immune-rejected by B6 recipients. In addition, the majority of teratomas formed by B6 EiPSCs were immunogenic in B6 mice with T cell infiltration, and apparent tissue damage and regression were observed in a small fraction of teratomas. Global gene expression analysis of teratomas formed by B6 ESCs and EiPSCs revealed a number of genes frequently overexpressed in teratomas derived from EiPSCs, and several such gene products were shown to contribute directly to the immunogenicity of the B6 EiPSC-derived cells in B6 mice. These findings indicate that, in contrast to derivatives of ESCs, abnormal gene expression in some cells differentiated from iPSCs can induce T-cell-dependent immune response in syngeneic recipients. Therefore, the immunogenicity of therapeutically valuable cells derived from patient-specific iPSCs should be evaluated before any clinic application of these autologous cells into the patients. PMID: 21572395 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Neoplastic transformation by TERT in FGF-2-expanded human mesenchymal stem cells. Int J Oncol. 2011 Jul;39(1):5-11 Authors: Yamaoka E, Hiyama E, Sotomaru Y, Onitake Y, Fukuba I, Sudo T, Sueda T, Hiyama K The low percentage of human mesenchymal stem cells (hMSCs) in bone marrow necessitates their in vitro expansion prior to clinical use in regenerative medicine. We evaluated the effect of long-term culture of hMSCs on telomere length and transformation capacity by TERT transfection. hMSCs were isolated from the bone marrow aspirates of 24 donors and cultured with fibroblast growth factor-2 (FGF-2). Six cell lines with >500 population doubling levels were considered immortalized. TERT was transfected into two of the six lines for a comparison of telomere length, telomerase activity, differential capacity, colony formation capacity in soft agar and tumorigenicity in immunodeficient (NOD-SCID) mice. hMSC lines exhibited elongated telomeres without the activation of telomerase and retained multi-lineage differentiation potential upon chondrogenic or adipogenic differentiation, while non-immortalized hMSCs showed a marked reduction in telomere length in the differentiation process. Immortalized hMSCs showed anchorage-independence and formed tumors in NOD-SCID mice. Histologically, these tumors consisted of differentiated cells such as fat tissue and cartilage. Two TERT-transfected hMSC lines showed high rates of tumor formation in NOD-SCID mice. These tumors were histologically similar to teratocarcinoma without differentiated cells. These cells may provide a model for the origin of cancer stem cells from adult stem cells, and indicate the possibility that telomerase activation has a major role in the malignant transformation of human stem cells. These data suggest that adult hMSCs have a potential for neoplastic transformation and have implications for the use of hMSCs in tissue engineering and regenerative medicine. PMID: 21573488 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | [Krox20 inactivation in the PNS leads to CNS/PNS boundary transgression by central glia]. Bull Acad Natl Med. 2010 Apr-May;194(4-5):743-4 Authors: Charnay P, Coulpier F, Decker L, Funalot B, Vallat JM, Garcia-Bragado F, Topilko P CNS/PNS interfaces constitute cell boundaries, defining territories with different neuronal and glial contents. Despite their potential implications for regenerative medicine, the mechanisms that restrict oligodendrocytes and astrocytes to the CNS and Schwann cells to the PNS are not known in mammals. To investigate the involvement of peripheral glia and myelin in CNS/PNS boundary maintenance, we first studied mutant mice. We found that inactivation of Krox20/Egr2, a master regulatory gene for myelination in Schwann cells, resulted in CNS/PNS boundary transgression by astrocytes and oligodendrocytes, and in myelination of nerve root axons by oligodendrocytes. In contrast, no such migration was observed in mice with the Trembler(J) mutation, which prevents PNS myelination without affecting Krox20 expression. These findings suggest that CNS/PNS boundary maintenance requires a new Krox20 function independent of myelination control. We also examined a patient with congenital amyelinating neuropathy, whose Schwann cells lack KROX20 protein. Interestingly, the patient's nerve roots were also invaded by oligodendrocytes and astrocytes, indicating that CNS/PNS boundary transgression by central glia can occur in human pathological situations and that the underlying mechanisms are the same as in mutant mice. PMID: 21568047 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Bioengineering Heart Muscle: A Paradigm for Regenerative Medicine. Annu Rev Biomed Eng. 2010 Jul 21; Authors: Vunjak-Novakovic G, Lui KO, Tandon N, Chien KR The idea of extending the lifetime of our organs is as old as humankind, fueled by major advances in organ transplantation, novel drugs, and medical devices. However, true regeneration of human tissue has becoming increasingly plausible only in recent years. The human heart has always been a focus of such efforts, given its notorious inability to repair itself following injury or disease. We discuss here the emerging bioengineering approaches to regeneration of heart muscle as a paradigm for regenerative medicine. Our focus is on biologically inspired strategies for heart regeneration, knowledge gained thus far about how to make a "perfect" heart graft, and the challenges that remain to be addressed for tissue-engineered heart regeneration to become a clinical reality. We emphasize the need for interdisciplinary research and training, as recent progress in the field is largely being made at the interfaces between cardiology, stem cell science, and bioengineering. Expected final online publication date for the Annual Review of Biomedical Engineering Volume 13 is July 15, 2011. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates. PMID: 21568715 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Storage time of transfused red blood cells and impact on clinical outcomes in hematopoietic stem cell transplantation. Transfusion. 2011 May 13; Authors: Kekre N, Chou A, Tokessey M, Doucette S, Tinmouth A, Tay J, Allan DS BACKGROUND: Red blood cell (RBC) transfusion may prolong recovery in some patients, perhaps due to changes that occur during more prolonged RBC storage. We examined the impact of RBC transfusion and the age of transfused RBC units on clinical outcomes in hematopoietic stem cell transplantation (HSCT). STUDY DESIGN AND METHODS: Data concerning RBC transfusions between Day 0 and Day +30 were analyzed for patients undergoing HSCT (n = 555) at a single institution. "Old" RBC units were defined as those stored for 15 days or longer. RESULTS: The proportion of old RBC units transfused and the mean age of transfused units did not correlate with 100-day nonrelapse mortality, organ-specific toxicity, length of stay (LOS), or incidence of intensive care unit (ICU) admission (p > 0.05). In comparing the 71 patients who received only old RBC units with 218 patients who received only "new" RBC units, there was no increase in adverse clinical outcomes after HSCT. Autologous transplant recipients (n = 355, 3.8 units/patient) were more likely to avoid RBC transfusion and received fewer units compared with allogeneic recipients (n = 200, 6.4 units/patient, p < 0.0001). The mean number of transfused RBC units was greater in patients admitted to the ICU (10.5 units vs. 3.7 units/patient, p < 0.01), correlated with longer LOS (p < 0.0001), and correlated with increasing number of organ systems with toxicity of at least Grade 2 (p < 0.0001). CONCLUSION: The importance of RBC storage time does not appear to influence clinical outcomes in HSCT. Patients with increased RBC transfusion requirements have greater toxicity after HSCT. Whether RBC transfusion contributes to toxicity, however, remains unclear. PMID: 21569047 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Treatment of long bone defects and non-unions: from research to clinical practice. Cell Tissue Res. 2011 May 17; Authors: Berner A, Reichert JC, Müller MB, Zellner J, Pfeifer C, Dienstknecht T, Nerlich M, Sommerville S, Dickinson IC, Schütz MA, Füchtmeier B The treatment of long bone defects and non-unions is still a major clinical and socio-economical problem. In addition to the non-operative therapeutic options, such as the application of various forms of electricity, extracorporeal shock wave therapy and ultrasound therapy, which are still in clinical use, several operative treatment methods are available. No consensus guidelines are available and the treatments of such defects differ greatly. Therefore, clinicians and researchers are presently investigating ways to treat large bone defects based on tissue engineering approaches. Tissue engineering strategies for bone regeneration seem to be a promising option in regenerative medicine. Several in vitro and in vivo studies in small and large animal models have been conducted to establish the efficiency of various tissue engineering approaches. Neverthelsss, the literature still lacks controlled studies that compare the different clinical treatment strategies currently in use. However, based on the results obtained so far in diverse animal studies, bone tissue engineering approaches need further validation in more clinically relevant animal models and in clinical pilot studies for the translation of bone tissue engineering approaches into clinical practice. PMID: 21574059 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Skeletal myotube integration with planar microelectrode arrays in vitro for spatially selective recording and stimulation: A comparison of neuronal and myotube extracellular action potentials. Biotechnol Prog. 2011 Mar 23; Authors: Langhammer CG, Kutzing MK, Luo V, Zahn JD, Firestein BL Microelectrode array (MEA) technology holds tremendous potential in the fields of biodetection, lab-on-a-chip applications, and tissue engineering by facilitating noninvasive electrical interaction with cells in vitro. To date, significant efforts at integrating the cellular component with this detection technology have worked exclusively with neurons or cardiac myocytes. We investigate the feasibility of using MEAs to record from skeletal myotubes derived from primary myoblasts as a way of introducing a third electrogenic cell type and expanding the potential end applications for MEA-based biosensors. We find that the extracellular action potentials (EAPs) produced by spontaneously contractile myotubes have similar amplitudes to neuronal EAPs. It is possible to classify myotube EAPs by biological signal source using a shape-based spike sorting process similar to that used to analyze neural spike trains. Successful spike-sorting is indicated by a low within-unit variability of myotube EAPs. Additionally, myotube activity can cause simultaneous activation of multiple electrodes, in a similar fashion to the activation of electrodes by networks of neurons. The existence of multiple electrode activation patterns indicates the presence of several large, independent myotubes. The ability to identify these patterns suggests that MEAs may provide an electrophysiological basis for examining the process by which myotube independence is maintained despite rapid myoblast fusion during differentiation. Finally, it is possible to use the underlying electrodes to selectively stimulate individual myotubes without stimulating others nearby. Potential uses of skeletal myotubes grown on MEA substrates include lab-on-a-chip applications, tissue engineering, co-cultures with motor neurons, and neural interfaces. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011. PMID: 21574266 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stem Cells, Including a Population of Very Small Embryonic-Like Stem Cells, are Mobilized Into Peripheral Blood in Patients After Skin Burn Injury. Stem Cell Rev. 2011 May 15; Authors: Drukała J, Paczkowska E, Kucia M, Młyńska E, Krajewski A, Machaliński B, Madeja Z, Ratajczak MZ BACKGROUND: Developmentally early cells, including hematopoietic stem progenitor cells (HSPCs), as well as very small embryonic-like stem cells (VSELs), are mobilized into peripheral blood (PB) in response to tissue and organ injury (e.g., heart infarct or stroke). OBJECTIVE: We seek to determine whether these cells are also mobilized into PB in patients with skin burn injuries. METHODS: Forty-four (44) patients (33-57 years of age) with total body surface burn area of 30-60%, as well as 23 healthy control subjects, were recruited and PB samples were harvested during the first 24 hours, day +2, and day +5 after burn injury and compared to normal controls. The circulating human CD34(+)CD133(+) cells enriched for HSPCs, as well as small CXCR4(+)CD34(+)CD133(+) subsets of Lin(-)CD45(-) cells that correspond to the population of VSELs, were counted by FACS and evaluated by direct immunofluorescence staining for pluripotency markers (Oct-4, Nanog, and SSEA-4). In parallel, we also measured by ELISA the serum concentration of factors that regulate stem cell trafficking, such as SDF-1, VEGF, and HGF. RESULTS: Our data indicate that skin burn injury mobilizes cells expressing stem cell-associated markers, such as CD133, CD34, and CXCR4, into PB. More importantly, we found an increase in the number of circulating primitive, small Oct-4(+)Nanog(+)SSEA-4(+)CXCR4(+)lin(-)CD45(-) VSELs. All these changes were accompanied by increased serum concentrations of SDF-1 and VEGF. LIMITATIONS: Further studies are needed to fully assess the role of mobilized stem cells in the healing process to see if they can contribute to skin regeneration. CONCLUSION: Skin burn injury triggers the mobilization of HSPCs and CXCR4(+) VSELs, while the significance and precise role of mobilized VSELs in skin repair requires further study. PMID: 21573962 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Comparison of short-run cell seeding methods for poly(L-lactide-co-1,5-dioxepan-2-one) scaffold intended for bone tissue engineering. Int J Artif Organs. 2011 May 9; Authors: Xing Z, Xue Y, Dånmark S, Finne-Wistrand A, Arvidson K, Hellem S, Yang ZQ, Mustafa K Constructs intended for bone tissue engineering are influenced by the initial cell seeding procedure. The seeding method should be rapid, convenient, improve cell spatial distribution, and have no negative effects on cellular viability and differentiation. This study aimed to compare the effect of short-run seeding methods (centrifuge and vortex) with a static method on the scaffolds prepared from poly(L-lactide-co-1,5-dioxepan-2-one) by solvent-casting particulate-leaching (SCPL) technique. Human osteoblast-like cells (HOB) were seeded by the three methods described above. The seeding efficiency was determined by attached cell numbers. Cellular proliferation was analyzed by WST-1 and dsDNA assay. Cell distribution was examined by scanning electron (SEM) and fluorescence microscopy. Expression of Alkaline Phosphatase (ALP), Collagen type I (Col I), Osteocalcin (OC) and Proliferating Cell Nuclear Antigen (PCNA) were determined by real time RT-PCR. Results indicated that centrifuge and vortex increased seeding efficiency and had no negative effects on cellular viability. The data obtained by the fluorescence microscope confirmed the SEM results that the vortex method improved cell distribution through the scaffolds more than the other two methods (p<0.05). The RT-PCR results showed no significant differences on the expression of mRNA between the three methods of the above markers. The vortex method was found to be a simple and feasible seeding method for the poly(L-lactide-co-1,5-dioxepan-2-one) scaffolds. PMID: 21574158 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Incorporation of osteoblasts (MG63) into 3D nanofibre matrices by simultaneous electrospinning and spraying in bone tissue engineering. Eur Cell Mater. 2011;21:384-95 Authors: Paletta JR, Mack F, Schenderlein H, Theisen C, Schmitt J, Wendorff JH, Agarwal S, Fuchs-Winkelmann S, Schofer MD Nanofibre scaffolds are suitable tools for bone tissue engineering. Mimicking the extracellular matrix, they allow for cell growth and differentiation. However, in large 3D scaffolds, uniform cell colonisation presents an unsolved problem. Our aim was to design and analyse a method of colonising nanofibre scaffolds, combining electrospinning of fibres and electrospraying of cells, to determine its impact on cell survival, growth, and gene expression. The osteoblast-like cell line MG63 was suspended in medium and electrosprayed into growing scaffolds of poly-(l-lactic acid) (PLLA) or PLLA/Col-I blend nanofibres. Fluorescein diacetate (FDA) staining was used to determine survival and growth over a 22 d culture period. Expression of osteocalcin (OC) and type I collagen (Col-I) genes was determined by real time PCR. Fluorescence microscopy was used to analyse Col-I and OC deposition, as well as cell densities. While spraying distance and cell density in the spraying solution influenced survival and cell density, the combination of electrospinning and electrospraying did not negatively influence the maintenance of the osteoblast phenotype. Furthermore, VEGF induction in response to hypoxia was not suppressed, but modulated by polymer composition. Therefore, simultaneous electrospinning and electrospraying is a suitable tool in producing nanofibre based 3D cell seeded scaffolds. PMID: 21574135 [PubMed - in process] | | | | | | | | | |  | |  | |  |
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