|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Kidney regeneration and resident stem cells. Organogenesis. 2011 Apr 1;7(2) Authors: Reule S, Gupta S Given its complexity, high metabolic activity, and excretory functions, the kidney is particularly susceptible to acute ischemic and toxin-mediated injury. Current therapies do not facilitate kidney regeneration, and there is an increasing interest in newer therapies that are based on cellular sources of kidney regeneration such as stem cell therapy. Our understanding of cellular sources of kidney regeneration and stem cells present in the adult kidney has dramatically evolved over the recent years. Herein, we have discussed the current understanding of kidney stem cells present in the adult mammalian kidney and their role in kidney regeneration. We have also summarized the best available evidence supporting the role of stem cells in kidney regeneration. PMID: 21613815 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | The California stem cell agency has posted its own version of the nomination of two Los Angeles men to become the new chairman of the $3 billion research enterprise.
The announcement came yesterday. The nominations were made last Friday and Monday and were covered at the time by a handful of news outlets.
The CIRM notice was a straight-forward, five-paragraph item and contained links on the | | | | | | | | | | | | | | | | | | | | | | | | | Calcium Homeostasis in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Stem Cell Rev. 2011 May 26; Authors: Lee YK, Ng KM, Lai WH, Chan YC, Lau YM, Lian Q, Tse HF, Siu CW RATIONALE: Cardiomyocytes generated from human induced pluripotent stem cells (hiPSCs) are suggested as the most promising candidate to replenish cardiomyocyte loss in regenerative medicine. Little is known about their calcium homeostasis, the key process underlying excitation-contraction coupling. OBJECTIVE: We investigated the calcium handling properties of hiPSC-derived cardiomyocytes and compared with those from human embryonic stem cells (hESCs). METHODS AND RESULTS: We differentiated cardiomyocytes from hiPSCs (IMR90 and KS1) and hESCs (H7 and HES3) with established protocols. Beating outgrowths from embryoid bodies were typically observed 2 weeks after induction. Cells in these outgrowths were stained positively for tropomyosin and sarcomeric alpha-actinin. Reverse-transcription polymerase chain reaction studies demonstrated the expressions of cardiac-specific markers in both hiPSC- and hESC-derived cardiomyocytes. Calcium handling properties of 20-day-old hiPSC- and hESC-derived cardiomyocytes were investigated using fluorescence confocal microscopy. Compared with hESC-derived cardiomyocytes, spontaneous calcium transients from both lines of hiPSC-derived cardiomyocytes were of significantly smaller amplitude and with slower maximal upstroke velocity. Better caffeine-induced calcium handling kinetics in hESC-CMs indicates a higher sacroplasmic recticulum calcium store. Furthermore, in contrast with hESC-derived cardiomyocytes, ryanodine did not reduce the amplitudes, maximal upstroke and decay velocity of calcium transients of hiPSC-derived cardiomyocytes. In addition, spatial inhomogeneity in temporal properties of calcium transients across the width of cardiomyocytes was more pronounced in hiPSC-derived cardiomyocytes than their hESC counterpart as revealed line-scan calcium imaging. Expressions of the key calcium-handling proteins including ryanodine recptor-2 (RyR2), sacroplasmic recticulum calcium-ATPase (SERCA), junction (Jun) and triadin (TRDN), were significantly lower in hiPSC than in hESCs. CONCLUSIONS: The results indicate the calcium handling properties of hiPSC-derived cardiomyocytes are relatively immature to hESC counterparts. PMID: 21614516 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stimulatory effect of 17β-estradiol on osteogenic differentiation potential of rat adipose tissue-derived stem cells. Gen Physiol Biophys. 2011 Jun;30(2):167-74 Authors: Taskiran D, Evren V Adipose tissue-derived stem cells (ADSCs) are considered as a potential cell source for regenerative medicine and tissue engineering. Although ADSCs have greater proliferation capacity than bone marrow stem cells (BMSCs), lower differentiation ability of these cells limits their utility in experimental and clinical studies. The purpose of this study was to investigate whether 17β-estradiol (E(2)) has a stimulatory effect on osteogenic differentiation potential of ADSCs in vitro. ADSCs were isolated from visceral adipose tissues of rats and treated with different concentrations of E(2) in osteogenic medium (OM) for 21 days. The differences in osteogenic differentiation potential of the cultures were assessed by von Kossa staining, measurement of alkaline phosphatase (ALP) activity and calcium levels. ADSCs cultured in OM supplemented with E(2) showed greater bone-like nodule formation and mineral deposition in comparing with the cells grown in OM. In addition, ALP activity and calcium levels also were significantly higher in the cultures exposed to E(2) than the cells treated only with OM (p < 0.005, n = 5). Our results suggest that E(2) may stimulate the osteogenic differentiation of ADSCs and therefore, can be used as an inducing agent to improve the efficiency of these cells in in vitro and in vivo studies. PMID: 21613672 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Eighth Annual International Umbilical Cord Blood Transplantation Symposium, San Francisco, California, June 3-5, 2010. Biol Blood Marrow Transplant. 2011 Feb;17(2):176-89 Authors: Laughlin M, Kurtzberg J, McMannis J, Petz L PMID: 20951820 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | System Integration - A Major Step toward Lab on a Chip. J Biol Eng. 2011 May 25;5(1):6 Authors: Sin ML, Gao J, Liao JC, Wong PK ABSTRACT: Microfluidics holds great promise to revolutionize various areas of biological engineering, such as single cell analysis, environmental monitoring, regenerative medicine, and point-of-care diagnostics. Despite the fact that intensive efforts have been devoted into the field in the past decades, microfluidics has not yet been adopted widely. It is increasingly realized that an effective system integration strategy that is low cost and broadly applicable to various biological engineering situations is required to fully realize the potential of microfluidics. In this article, we review several promising system integration approaches for microfluidics and discuss their advantages, limitations, and applications. Future advancements of these microfluidic strategies will lead toward translational lab-on-a-chip systems for a wide spectrum of biological engineering applications. PMID: 21612614 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A rapid in-vivo assay system for analyzing the organogenetic capacity of human kidney cells. Organogenesis. 2011 Apr 1;7(2) Authors: Noiman T, Buzhor E, Metsuyanim S, Harari-Steinberg O, Morgenshtern C, Dekel B, Goldstein RS Transplantation of human kidney-derived cells is a potential therapeutic modality for promoting regeneration of diseased renal tissue. However, assays that determine the ability of candidate populations for renal cell therapy to undergo appropriate differentiation and morphogenesis are limited. We report here a rapid and humane assay for characterizing tubulogenic potency utilizing the well-established chorioallantoic membrane (CAM) of the chick embryo. Adult human kidney-derived cells expanded in monolayer were suspended in Matrigel and grafted onto the CAM. After a week, grafts were assessed histologically. Strikingly, many of the renal cells self-organized into tubular structures. Host blood vessels penetrated and presumably fed the grafts. Immuno- and histochemical staining revealed that tubular structures were epithelial, but not blood vessels. Some of the cells both within and outside the tubules were dividing. Analysis for markers of proximal and distal renal tubules revealed that grafts contained individual cells of a proximal tubular phenotype and many tubules of distal tubule character. Our results demonstrate that the chick CAM is a useful xenograft system for screening for differentiation and morphogenesis by cells with potential use in renal regenerative medicine. PMID: 21613816 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Evaluating differentiation propensity of in-house derived human embryonic stem cell lines KIND-1 and KIND-2. In Vitro Cell Dev Biol Anim. 2011 May 26; Authors: Nagvenkar P, Pethe P, Pawani H, Telang J, Kumar N, Hinduja I, Zaveri K, Bhartiya D Human embryonic stem (hES) cells possess the ability to self-renew indefinitely and provide a potential source of differentiated progeny representing all three embryonic germ layers. Although hES cell lines share the expression of typical pluripotency markers, limited data is available regarding their differentiation capabilities. We have earlier reported the in-house derivation of two hES cell lines, KIND-1 and KIND-2 on human feeders. Here, we describe a comparative study carried out on both these cell lines to better understand the differentiation potential of KIND-1 and KIND-2 by gene expression analysis of representative gene transcripts reflecting pluripotency and the three germ layers viz. ectoderm, mesoderm, and endoderm. Gene expression analysis and immunolocalization studies were undertaken on (a) 7- and 14-d old embryoid bodies (EBs) (b) spontaneously differentiated cells from EBs, (c) cells derived from EBs under the influence of various growth factor treatments and (d) KIND-1 and KIND-2 cells co-cultured on mouse embryonic visceral endoderm-like feeder (END-2). Despite both the cell lines being XX, derived, passaged, and cultured similarly, KIND-1 exhibits preferential differentiation towards endodermal lineage whereas KIND-2 spontaneously forms beating cardiomyocytes. Perhaps the occurrence of discrete epigenetic profile in both the cell lines predisposes them to encompass different developmental potential in vitro. Our data provide evidence for existence of distinct differentiation propensity among hES cell lines and emphasizes the need to derive more hES cell lines for future regenerative medicine. PMID: 21614653 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Further insights into the characterization of equine adipose tissue-derived mesenchymal stem cells. Vet Res Commun. 2011 May 26; Authors: Raabe O, Shell K, Würtz A, Reich CM, Wenisch S, Arnhold S Adipose tissue-derived stem cells (ADSCs) represent a promising subpopulation of adult stem cells for tissue engineering applications in veterinary medicine. In this study we focused on the morphological and molecular biological properties of the ADSCs. The expression of stem cell markers Oct4, Nanog and the surface markers CD90 and CD105 were detected using RT-PCR. ADSCs showed a proliferative potential and were capable of adipogenic and osteogenic differentiation. Expression of Alkaline phosphatase (AP), phosphoprotein (SPP1), Runx2 and osteocalcin (OC) mRNA were positive in osteogenic lineages and peroxisome proliferator activated receptor (Pparγ2) mRNA was positive in adipogenic lineages. ADSCs show stem cell and surface marker profiles and differentiation characteristics that are similar to but distinct from other adult stem cells, such as bone marrow-derived mesenchymal stem cells (BM-MSCs). The availability of an easily accessible and reproducible cell source may greatly facilitate the development of stem cell based tissue engineering and therapies for regenerative equine medicine. PMID: 21614641 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The effects of vibration loading on adipose stem cell number, viability and differentiation towards bone-forming cells. J R Soc Interface. 2011 May 25; Authors: Tirkkonen L, Halonen H, Hyttinen J, Kuokkanen H, Sievänen H, Koivisto AM, Mannerström B, Sándor GK, Suuronen R, Miettinen S, Haimi S Mechanical stimulation is an essential factor affecting the metabolism of bone cells and their precursors. We hypothesized that vibration loading would stimulate differentiation of human adipose stem cells (hASCs) towards bone-forming cells and simultaneously inhibit differentiation towards fat tissue. We developed a vibration-loading device that produces 3g peak acceleration at frequencies of 50 and 100 Hz to cells cultured on well plates. hASCs were cultured using either basal medium (BM), osteogenic medium (OM) or adipogenic medium (AM), and subjected to vibration loading for 3 h d(-1) for 1, 7 and 14 day. Osteogenesis, i.e. differentiation of hASCs towards bone-forming cells, was analysed using markers such as alkaline phosphatase (ALP) activity, collagen production and mineralization. Both 50 and 100 Hz vibration frequencies induced significantly increased ALP activity and collagen production of hASCs compared with the static control at 14 day in OM. A similar trend was detected for mineralization, but the increase was not statistically significant. Furthermore, vibration loading inhibited adipocyte differentiation of hASCs. Vibration did not affect cell number or viability. These findings suggest that osteogenic culture conditions amplify the stimulatory effect of vibration loading on differentiation of hASCs towards bone-forming cells. PMID: 21613288 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Engineering neuronal growth cones to promote axon regeneration over inhibitory molecules. Proc Natl Acad Sci U S A. 2011 Mar 22;108(12):5057-62 Authors: Hur EM, Yang IH, Kim DH, Byun J, Saijilafu , Xu WL, Nicovich PR, Cheong R, Levchenko A, Thakor N, Zhou FQ Neurons in the central nervous system (CNS) fail to regenerate axons after injuries due to the diminished intrinsic axon growth capacity of mature neurons and the hostile extrinsic environment composed of a milieu of inhibitory factors. Recent studies revealed that targeting a particular group of extracellular inhibitory factors is insufficient to trigger long-distance axon regeneration. Instead of antagonizing the growing list of impediments, tackling a common target that mediates axon growth inhibition offers an alternative strategy to promote axon regeneration. Neuronal growth cone, the machinery that derives axon extension, is the final converging target of most, if not all, growth impediments in the CNS. In this study, we aim to promote axon growth by directly targeting the growth cone. Here we report that pharmacological inhibition or genetic silencing of nonmuscle myosin II (NMII) markedly accelerates axon growth over permissive and nonpermissive substrates, including major CNS inhibitors such as chondroitin sulfate proteoglycans and myelin-associated inhibitors. We find that NMII inhibition leads to the reorganization of both actin and microtubules (MTs) in the growth cone, resulting in MT reorganization that allows rapid axon extension over inhibitory substrates. In addition to enhancing axon extension, we show that local blockade of NMII activity in axons is sufficient to trigger axons to grow across the permissive-inhibitory border. Together, our study proposes NMII and growth cone cytoskeletal components as effective targets for promoting axon regeneration. PMID: 21383151 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Intrafibrillar collagen mineralization produced by biomimetic hierarchical nanoapatite assembly. Adv Mater. 2011 Feb 22;23(8):975-80 Authors: Liu Y, Li N, Qi YP, Dai L, Bryan TE, Mao J, Pashley DH, Tay FR PMID: 21341310 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Further insights into the characterization of equine adipose tissue-derived mesenchymal stem cells. Vet Res Commun. 2011 May 26; Authors: Raabe O, Shell K, Würtz A, Reich CM, Wenisch S, Arnhold S Adipose tissue-derived stem cells (ADSCs) represent a promising subpopulation of adult stem cells for tissue engineering applications in veterinary medicine. In this study we focused on the morphological and molecular biological properties of the ADSCs. The expression of stem cell markers Oct4, Nanog and the surface markers CD90 and CD105 were detected using RT-PCR. ADSCs showed a proliferative potential and were capable of adipogenic and osteogenic differentiation. Expression of Alkaline phosphatase (AP), phosphoprotein (SPP1), Runx2 and osteocalcin (OC) mRNA were positive in osteogenic lineages and peroxisome proliferator activated receptor (Pparγ2) mRNA was positive in adipogenic lineages. ADSCs show stem cell and surface marker profiles and differentiation characteristics that are similar to but distinct from other adult stem cells, such as bone marrow-derived mesenchymal stem cells (BM-MSCs). The availability of an easily accessible and reproducible cell source may greatly facilitate the development of stem cell based tissue engineering and therapies for regenerative equine medicine. PMID: 21614641 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | 3D-CONSTRUCT BIOREACTOR CONDITIONING IN HUMAN TENDON TISSUE ENGINEERING. Tissue Eng Part A. 2011 May 26; Authors: Woon CY, Kraus A, Raghavan S, Pridgen BC, Megerle K, Pham H, Chang J Human tendon tissue engineering attempts to address the shortage of autologous tendon material arising from mutilating injuries and diseases of the hand and forearm. It is important to maximize the tissue engineered construct's (TEC's) biomechanical properties to ensure that the construct is in its strongest possible state prior to reimplantation. In this study, we sought to determine the bioreactor treatment parameters that affect these properties. Using small- and large-chamber 3d-construct bioreactors (SCB and LCB respectively), we applied cyclic axial load to TECs comprising reseeded human flexor and extensor tendons of the hand. First, small-sample pilot studies using the LCB were performed on matched-paired full-length flexor tendons to establish proof of concept. Next, large-sample studies using the SCB were performed on matched-paired extensor tendon segments to determine how reseeding, load duty cycle, load magnitude, conditioning duration, and testing delay affected ultimate tensile stress (UTS) and elastic modulus (EM). We found that compared with reseeded matched-paired controls under dynamic-loading at 1.25N per TEC for 5 days, (1) acellular TECs had lower UTS (p=0.04) and EM (p<0.01), (2) unloaded TECs had lower UTS (p=0.01) and EM (p=0.02), (3) static-loaded TECs had lower UTS (p=0.01) and EM (p<0.01), (4) TECs conditioned for 3 days had lower UTS (p=0.03) and EM (p=0.04), and (5) TECs conditioned for 8 days had higher UTS (p=0.04) and EM (p=0.01). However, TECs conditioned at higher loads (2.5N per TEC) and lower loads (0.625N per TEC) possessed similar UTS (p=0.83 and p=0.89 respectively) and EM (p=0.48 and p=0.89 respectively) as controls stimulated with 1.25N per TEC. Following cycle completion, there is attrition of UTS (p=0.03) and EM (p=0.04) over a 2-day period. Our study showed that the material properties of human allograft TECs can be enhanced by reseeding and dynamic-conditioning. While conditioning duration has a significant effect on material properties, the load magnitude does not. The issue of attrition in biomechanical properties with time following cycle completion must be addressed before bioreactor preconditioning can be successfully introduced as a step in the processing of these constructs for clinical application. PMID: 21612572 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fabrication of engineered heart tissue grafts from alginate/collagen barium composite microbeads. Biomed Mater. 2011 May 26;6(4):045002 Authors: Bai XP, Zheng HX, Fang R, Wang TR, Hou XL, Li Y, Chen XB, Tian WM Cardiac tissue engineering holds great promise for the treatment of myocardial infarction. However, insufficient cell migration into the scaffolds used and inflammatory reactions due to scaffold biodegradation remain as issues to be addressed. Engineered heart tissue (EHT) grafts fabricated by means of a cell encapsulation technique provide cells with a tissue-like environment, thereby potentially enhancing cellular processes such as migration, proliferation, and differentiation, and tissue regeneration. This paper presents a study on the fabrication and characterization of EHT grafts from novel alginate/collagen composite microbeads by means of cell encapsulation. Specifically, the microbeads were fabricated from alginate and collagen by barium ion cross-linking, with neonatal rat cardiomyocytes encapsulated in the composite microbeads during the fabrication of the EHT grafts. To evaluate the suitablity of these EHT grafts for heart muscle repair, the growth of cardiac cells in the microbeads was examined by means of confocal microscopy and staining with DAPI and F-actin. The EHT grafts were analyzed by scanning electron microscopy and transmission electron microscopy, and the contractile function of the EHT grafts monitored using a digital video camera at different time points. The results show the proliferation of cardiac cells in the microbeads and formation of interconnected multilayer heart-like tissues, the presence of well-organized and dense cell structures, the presence of intercalated discs and spaced Z lines, and the spontaneous synchronized contractility of EHT grafts (at a rate of 20-30 beats min(-1) after two weeks in culture). Taken together, these observations demonstrate that the novel alginate/collagen composite microbeads can provide a tissue-like microenvironment for cardiomyocytes that is suitable for fabricating native heart-like tissues. PMID: 21613722 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Uncovering the behaviors of individual cells within a multicellular microvascular community. Proc Natl Acad Sci U S A. 2011 Mar 22;108(12):5133-8 Authors: Parsa H, Upadhyay R, Sia SK Although individual cells vary in behavior during the formation of tissues, the nature of such variations are largely uncharacterized. Here, we tracked the morphologies and motilities of ~300 human endothelial cells from an initial dispersed state to the formation of capillary-like structures, distilling the dynamics of tissue morphogenesis into an array of ~36,000 numerical phenotypes. Quantitative analysis of population averages revealed two previously unidentified phases in which the cells spread before forming connections with neighboring cells and where the microvascular plexus stabilized before spatially reorganizing. Analysis at the single-cell level showed that in contrast to the population-averaged behavior, most cells followed distinct temporal patterns that were not reflected in the bulk average. Interestingly, some of these behavioral patterns correlated to the cells' final structural role within the plexus. Knowledge of how individual cells or groups of cells behave enhances our understanding of how native tissues self-organize and could ultimately enable more precise approaches for engineering tissues and synthesizing multicellular communities. PMID: 21383144 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Stimulatory effect of 17β-estradiol on osteogenic differentiation potential of rat adipose tissue-derived stem cells. Gen Physiol Biophys. 2011 Jun;30(2):167-74 Authors: Taskiran D, Evren V Adipose tissue-derived stem cells (ADSCs) are considered as a potential cell source for regenerative medicine and tissue engineering. Although ADSCs have greater proliferation capacity than bone marrow stem cells (BMSCs), lower differentiation ability of these cells limits their utility in experimental and clinical studies. The purpose of this study was to investigate whether 17β-estradiol (E(2)) has a stimulatory effect on osteogenic differentiation potential of ADSCs in vitro. ADSCs were isolated from visceral adipose tissues of rats and treated with different concentrations of E(2) in osteogenic medium (OM) for 21 days. The differences in osteogenic differentiation potential of the cultures were assessed by von Kossa staining, measurement of alkaline phosphatase (ALP) activity and calcium levels. ADSCs cultured in OM supplemented with E(2) showed greater bone-like nodule formation and mineral deposition in comparing with the cells grown in OM. In addition, ALP activity and calcium levels also were significantly higher in the cultures exposed to E(2) than the cells treated only with OM (p < 0.005, n = 5). Our results suggest that E(2) may stimulate the osteogenic differentiation of ADSCs and therefore, can be used as an inducing agent to improve the efficiency of these cells in in vitro and in vivo studies. PMID: 21613672 [PubMed - in process] | | | | | | | | | |  | |  | |  |
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