|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Persistent high glucose concentrations alter the regenerative potential of mesenchymal stem cells. Stem Cells Dev. 2010 Dec;19(12):1875-84 Authors: Cramer C, Freisinger E, Jones RK, Slakey DP, Dupin CL, Newsome ER, Alt EU, Izadpanah R Type 2 diabetes is associated with numerous long-term complications. This study aims to investigate whether impaired function of tissue-resident multipotent cells play role in pathogenesis of allied complications. Adipose-tissue-derived mesenchymal stem cells (ASCs) derived from nondiabetic (nASCs) and diabetic (dASCs) donors were compared with regard to glucose metabolism, cell replication, apoptosis, and differentiation potential. The data evidenced that elevation of glucose reduces proliferative capacity of both dASCs and nASCs, but impacts dASCs more significantly. Incorporation of insulin enhanced cell replication especially in nASCs. dASCs show higher levels of cellular senescence and apoptosis than nASCs. Unlike nASCs, apoptosis is induced via intrinsic pathway in dASCs. Data also evidenced that high glucose concentrations cause prominent disparities in nASCs and dASCs in expression of genes involved in insulin resistance such as adiponectin and resistin. Some changes in gene expression were irreversible in dASCs when treated with insulin. Additionally, high glucose concentrations reduce osteogenic and chondrogenic potential of ASCs, but enhance adipogenic potential. These results indicate that in addition to involvement in insulin resistance, impaired function of mesenchymal stem cells that reside in adipose tissue as one of the major sources of adult stem cells might be responsible for complications related to diabetes type 2. PMID: 20380516 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | The directors of the California stem cell agency are preparing to jump into a brutal political fray in the hallowed halls of Congress that pits, in the views of some, a "global corporatist elite" against American entrepreneurs and inventors.
It is all about patent law and so-called reform. More than 100 lobbying firms representing at least 267 organizations have already joined the battle. | | | | | | | | | | | | | | | | | | | | | | | | The Consumer Watchdog organization today endorsed a Los Angeles cardiologist as the new chairman of the $3 billion California stem cell agency, declaring that it is time to "correct the agency's dysfunctional management structure."
Writing in an op-ed piece in this morning's Sacramento Bee, John M. Simpson, stem cell project director of the Santa Monica organization, called for the election of | | | | | | | | | | | | | | | | | | | | | | | | | My email provider seems to be having difficulties and is bouncing back messages to senders. For readers who may be trying to email me, please use this alternate email address: svhopalong(at)gmail.com. | | | | | | | | | | | | | | | | | | | | | | | | | Bone marrow cells repair cigarette smoke-induced emphysema in rats. Am J Physiol Lung Cell Mol Physiol. 2011 May 27; Authors: Huh JW, Kim SY, Lee JH, Lee JS, Ta QV, Kim MJ, Oh YM, Lee YS, Lee SD The therapeutic potential of stem cells in chronic obstructive pulmonary disease is not well known, although stem cell therapy is effective in models of other pulmonary diseases. We tested the capacities of bone marrow cells (BMCs), mesenchymal stem cells (MSCs), and conditioned media of MSCs (MSC-CM) to repair cigarette smoke-induced emphysema. Inbred female Lewis rats were exposed to cigarette smoke for 6 months and then received BMCs, MSCs, or MSC-CM from male Lewis rats. For 2 months after injection, the BMC treatment gradually alleviated the cigarette smoke-induced emphysema and restored the increased mean linear intercept. The BMC treatment significantly increased cell proliferation and the number of small pulmonary vessels, reduced apoptotic cell death, attenuated the mean pulmonary arterial pressure, and inhibited muscularization in small pulmonary vessels. However, only a few male donor cells were detected from 1 day to 1 month after BMC administration. The MSCs and cell-free MSC-CM also induced the repair of emphysema and increased the number of small pulmonary vessels. Our data show that BMC, MSC, or MSC-CM treatment repaired cigarette smoke-induced emphysema. The repair activity of these treatments is consistent with a paracrine effect rather than stem cell engraftment because most of the donor cells disappeared and because cell-free MSC-CM also induced the repair. PMID: 21622846 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cells cardiac differentiation in 3D systems. Front Biosci (Schol Ed). 2011;3:901-918 Authors: Spadaccio C, Rainer A, Chachques JC, Covino E, Herreros J, Genovese JA Cardiac regeneration requires a complex cascade of events. Stem cell therapy and tissue engineering are newly emerging tools with promising potential for recover or replace of damaged cardiac tissue. There are many factors, most of them still no clarified, that limit the effectiveness of these treatments and their translation to the clinic. Cells should graft, survive and functionally integrate to the target organ in order to have a chance to restore its function. As in original tissues, a complex and well defined set of signals, many of them coming from the extracellular matrix, is required for normal cell physiology. Biomaterials science gives us important tools to build this extracellular matrix. Functionalized 3D systems can provide the correct environment and act as a delivery system for genes or gene products, guiding the therapeutic cells to the functional phenotype. PMID: 21622240 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Reprogramming of Mouse and Human Cells to Pluripotency Using Mature MicroRNAs. Cell Stem Cell. 2011 May 25; Authors: Miyoshi N, Ishii H, Nagano H, Haraguchi N, Dewi DL, Kano Y, Nishikawa S, Tanemura M, Mimori K, Tanaka F, Saito T, Nishimura J, Takemasa I, Mizushima T, Ikeda M, Yamamoto H, Sekimoto M, Doki Y, Mori M Induced pluripotent stem cells (iPSCs) can be generated from differentiated human and mouse somatic cells using transcription factors such as Oct4, Sox2, Klf4, and c-Myc. It is possible to augment the reprogramming process with chemical compounds, but issues related to low reprogramming efficiencies and, with a number of protocols, residual vector sequences, remain to be resolved. We show here that it is possible to reprogram mouse and human cells to pluripotency by direct transfection of mature double-stranded microRNAs (miRNAs). Our approaches use a combination of mir-200c plus mir-302 s and mir-369 s family miRNAs. Because this reprogramming method does not require vector-based gene transfer, it holds significant potential for biomedical research and regenerative medicine. PMID: 21620789 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Systematic parameter optimization of a Me(2)SO- and serum-free cryopreservation protocol for human mesenchymal stem cells. Cryobiology. 2011 May 17; Authors: Freimark D, Sehl C, Weber C, Hudel K, Czermak P, Hofmann N, Spindler R, Glasmacher B Human mesenchymal stem cells (hMSCs) have great potential for clinical therapy and regenerative medicine. One major challenge concerning their application is the development of an efficient cryopreservation protocol since current methods result in a poor viability and high differentiation rates. A high survival rate of cryopreserved cells requires an optimal cooling rate and the presence of cryoprotective agents (CPA) in sufficient concentrations. The most widely used CPA, dimethylsulfoxide (Me(2)SO), is toxic at high concentrations at temperatures >4°C and has harmful effects on the biological functionality of stem cell as well as on treated patients. Thus, this study investigates different combinations of non-cytotoxic biocompatible substances, such as ectoin and proline, as potential CPAs in a systematic parametric optimization study in comparison to Me(2)SO as control and a commercial freezing medium (Biofreeze®, Biochrom). Using a freezing medium containing a low proline (1%, w/v) and higher ectoin (10%, w/v) amount revealed promising results although the highest survival rate was achieved with the Biofreeze® medium. Cryomicroscopic experiments of hMSCs revealed nucleation temperatures ranging from -16 to -25°C. The CPAs, beside Me(2)SO, did not affect the nucleation temperature. In most cases, cryomicroscopy revealed intracellular ice formation (IIF) during the cryopreservation cycle for all cryoprotocols. The occurence of IIF during thawing increased with the cooling rate. In case of hMSC there was no correlation between the rate of IIF and the post-thaw cell survival. After thawing adipogenic differentiation of the stem cells demonstrated cell functionality. PMID: 21620818 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Analysis of the motivation for hematopoietic stem cell donation. Transplant Proc. 2011 May;43(4):981-4 Authors: Aurelio MT, Aniasi A, Haworth SE, Colombo MB, Dimonopoli T, Mocellin MC, Poli F, Torelli R, Crespiatico L, Serafini M, Scalamogna M The Italian Bone Marrow Donor Register is the institutional organization for management of unrelated hematopoietic stem cell donors. The law requires only a donor's clinical history, but not a psychosocial profile for registration. We have studied the donor's motivation for enlistment on the donor registry and the medical staff's need for this information to interact correctly with the donor. For this purpose we distributed a questionnaire to new donors at the 20 centers in the Lombardy Region over a period of 1 year. The analysis of the responses revealed a prevalence of extrinsic motivations that would not ensure continued registration for donation. Therefore, it is necessary that the donor be well informed and better educated about all aspects of donation, in order to produce a shift to an intrinsic motivation. This objective can be facilitated via professional training of health workers in communication. PMID: 21620031 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Regenerative medicine and tissue engineering in orthopaedic surgery. Front Biosci (Elite Ed). 2011;3:923-944 Authors: Ivkovic A, Marijanovic I, Hudetz D, Porter RM, Pecina M, Evans CH Orthopedic surgery is going through a serious paradigm shift; instead of simply replacing damaged tissues with prosthetic or allograft material, the aim is to regenerate them. This endeavor has generated the field of regenerative orthopaedics, an increasingly expanding area of research with hopes of providing new and better treatments for diseases and injuries affecting the musculoskeletal system. As part of this process, we are witnessing a substantial accumulation of new cellular and molecular insights into connective tissue function, coupled with emerging new concepts in stem cell biology and scaffolding technologies. Indeed, any successful strategy to regenerate musculoskeletal tissues can be portrayed as an intricate interplay between the three main constituents of the regenerative system: cells, environment and scaffolds. This review is not meant to be exhaustive and comprehensive, but aims to highlight concepts and key advances in the field of regenerative orthopaedics and tissue engineering, as well as to present current possibilities for clinical translation. PMID: 21622102 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Large-scale production of murine embryonic stem cell-derived osteoblasts and chondrocytes on microcarriers in serum-free media. Biomaterials. 2011 May 25; Authors: Alfred R, Taiani JT, Krawetz RJ, Yamashita A, Rancourt DE, Kallos MS The generation of tissue-engineered constructs from stem cells for the treatment of musculoskeletal diseases may have immense impact in regenerative medicine, but there are difficulties associated with stem cell culture and differentiation, including the use of serum. Here we present serum-free protocols for the successful production of murine embryonic stem cell (mESC) derived osteoblasts and chondrocytes on CultiSpher S macroporous microcarriers in stirred suspension bioreactors. Various inoculum forms and agitation rates were investigated. Produced osteogenic cells were implanted ectopically into SCID mice and orthotopically into a murine burr-hole fracture model. Osterix, osteocalcin and collagen type I were upregulated in osteogenic cultures, while aggrecan and collagen type II were upregulated in chondrogenic cultures. Histological analysis using alizarin red S, von Kossa and alcian blue staining confirmed the presence of osteoblasts and chondrocytes, respectively in cultured microcarriers and excised tissue. Finally, implantation of derived cells into a mouse fracture model revealed cellular integration without any tumor formation. Overall, microcarriers may provide a supportive scaffold for ESC expansion and differentiation in a serum-free bioprocess for in vivo implantation. These findings lay the groundwork for the development of clinical therapies for musculoskeletal injuries and diseases using hESCs and iPS cells. PMID: 21620471 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Perfusion circuit concepts for hollow-fiber bioreactors used as in vitro cell production systems or ex vivo bioartificial organs. Int J Artif Organs. 2011 May 23; Authors: Balmert SC, McKeel D, Triolo F, Gridelli B, Zeilinger K, Bornemann R, Gerlach JC For the development and implementation of primary human cell- and stem cell-based applications in regenerative medicine, large amounts of cells with well-defined characteristics are needed. Such cell quantities can be obtained with the use of hollow fiber-based bioreactors. While the use of such bioreactors generally requires a perfusion circuit, the configuration and complexity of such circuits is still in debate. We evaluated various circuit configurations to investigate potential perfusate volume shifts in the arterial and venous sides of the perfusion circuit, as well as in the feed and waste lines. Volume shifts with changes in flow conditions were measured with graduated bubble traps in the circuit, and perfusion pressures were measured at three points in the circuits. The results of this study demonstrate that the bioreactor perfusion circuit configuration has an effect on system pressures and volume shifts in the circuit. During operation, spikes in post-bioreactor pressures caused detrimental, potentially dangerous volume shifts in the feed and waste lines for configurations that lacked feed pumps and/or waste line check valves. Our results indicate that a more complex tubing circuit adds to safety of operation and avoids technical challenges associated with the use of large-scale hollow fiber bioreactors (e.g., for extracorporeal liver support or erythrocyte production from hematopoietic stem cells), including volume shifts and the need for a large reservoir. Finally, to ensure safe use of bioreactors, measuring pre-, intra-, and post-bioreactor pressures, and pump operation control is also advisable, which suggests the use of specifically developed bioreactor perfusion devices. PMID: 21623585 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The power of Pasteur's quadrant: cardiovascular disease at the turn of the century. FASEB J. 2011 Jun;25(6):1788-92 Authors: Levin RI, Fishman GI During the life span of The FASEB Journal, the decline in cardiovascular mortality was astonishing as the fundamental bases of the complex syndromes of cardiovascular disease were illuminated. In this Silver Anniversary Review, we highlight a few pivotal advances in the field and relate them to research in Pasteur's quadrant, the region of investigation driven by both a desire for fundamental understanding and the consideration of its use. In the second half of the 20th century, we advanced from little pathophysiologic understanding to a near-complete understanding and effective, evidence-based therapeutics for vascular disorders and a similar development of pharmacotherapy to address heart failure, primarily through agents that antagonize the excessive concentration of circulating neurohumoral agents. In the current era, we have witnessed "the rise of the machines," from stents to cardiac resynchronization therapy. The next wave of treatments will build on an increasingly sophisticated understanding of the molecular determinants of cardiovascular disorders. We briefly consider the promise of regenerative medicine and are intrigued by the possibility for the direct reprogramming of resident cardiac fibroblasts into cardiomyocytes. As for the future, genomic profiling should help physicians recommend individualized risk factor modification targeted to prevent specific manifestations of cardiovascular disease. Transcriptional and biomarker analyses will almost surely be used individually to tailor therapy for those at risk of or experiencing cardiovascular disease. Given the ongoing exponential expansion of scientific knowledge, all of human ingenuity will be needed to fully utilize the power of Pasteur's quadrant and to unleash another quarter century in cardiology as scientifically fruitful and effective on human health as the last.-Levin, R. I., Fishman, G. I. The power of Pasteur's quadrant: cardiovascular disease at the turn of the century. PMID: 21622696 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Ginkgolide B promotes proliferation and functional activities of bone marrow-derived endothelial progenitor cells: involvement of Akt/eNOS and MAPK/p38 signaling pathways. Eur Cell Mater. 2011;21:459-469 Authors: Tang Y, Huang B, Sun L, Peng X, Chen X, Zou X Bone marrow-derived, circulating endothelial progenitor cells (EPCs) contribute to neovascularization in various diseases, and represent a very interesting alternative cell source for enhancing vasculogenesis in regenerative medicine. In this study, we investigated the effects of Ginkgolide B (GB) on proliferation and differentiation of EPCs, and the involved signaling pathway in vitro. EPC proliferation, migration, adhesion and angiogenesis activities were assessed with the WST-8 assay, Transwell chamber assay, cell counting and angiogenesis kit, respectively. Apoptosis was detected with annexin V and propidium iodide staining. The protein expression of angiogenesis-related makers was detected by Western blot, and related gene expression was determined by real-time polymerase chain reaction (RT-PCR). The results showed that GB promoted the proliferation and endothelial gene expression, and markedly enhanced vascular endothelial growth factor-induced migration response and the capability to incorporate into the vascular networks in EPCs. GB protected EPCs from H2O2-induced cell death. GB induced the phosphorylation of eNOS, Akt and p38, which in turn promoted cell proliferation and function. In conclusion, the present study demonstrates that GB, at a near medical applied dose, increases the number and functional activities of EPCs with involvement of Akt/endothelial nitric oxide synthase and mitogen-activated protein kinase (MAPK)/p38 signal pathways. These findings raise the intriguing possibility that GB may play an important role in the protection and revascularization of blood vessels. PMID: 21623570 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Adipose tissue-deprived stem cells acquire cementoblast features treated with dental follicle cell conditioned medium containing dentin non-collagenous proteins in vitro. Biochem Biophys Res Commun. 2011 May 17; Authors: Wen X, Nie X, Zhang L, Liu L, Deng M Adipose tissue-derived stem cells (ADSCs), which are easily harvested and show excellent pluripotency potential, have generated considerable interest in regenerative medicine. In this study, the differentiation of ADSCs was assessed after treatment with dental follicle cell conditioned medium (DFCCM) containing dentin non-collagenous proteins (dNCPs). ADSCs exhibited a fibroblast-like morphology and high proliferative capacity. However, after treatment with dNCPs/DFCCM, ADSCs changed from a fibroblast-like to cementoblast-like morphology and significantly lost their proliferative capacity. Alkaline phosphatase activity and in vitro mineralization behaviour of ADSCs were significantly enhanced. Mineralization-related markers including cementum attachment protein, bone sialoprotein, osteocalcin, osteopontin and osteonectin were detected at mRNA or protein levels, whereas dentin sialophosphoprotein and dentin sialoprotein were not detected, implying a cementoblast-like phenotype. These results demonstrate that ADSCs acquired cementoblast features in vitro with dNCPs/DFCCM treatment and could be a potential source of cementogenic cells for periodontal regeneration. PMID: 21619870 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Nonmyogenic Cells in Skeletal Muscle Regeneration. Curr Top Dev Biol. 2011;96C:139-165 Authors: Paylor B, Natarajan A, Zhang RH, Rossi F Although classical dogma dictates that satellite cells are the primary cell type involved in skeletal muscle regeneration, alternative cell types such as a variety of inflammatory and stromal cells are also actively involved in this process. A model describing myogenic cells as direct contributors to regeneration and nonmyogenic cells from other developmental sources as important accessories has emerged, with similar systems having been described in numerous other tissues in the body. Increasing evidence supports the notion that inflammatory cells function as supportive accessory cells, and are not merely involved in clearing damage following skeletal muscle injury. Additionally, recent studies have highlighted the role of tissue resident mesenchymal cell populations as playing a central role in regulating regeneration. These "accessory" cell populations are proposed to influence myogenesis via direct cell contact and secretion of paracrine trophic factors. The basic foundations of accessory cell understanding should be recognized as a crucial component to all prospects of regenerative medicine, and this chapter intends to provide a comprehensive background on the current literature describing immune and tissue-resident mesenchymal cells' role in skeletal muscle regeneration. PMID: 21621070 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Regulatory T-Cell (Treg) hybridoma as a novel tool to study Foxp3 regulation and Treg fate. J Autoimmun. 2011 May 27; Authors: Sharma R, Sung SS, Ju CY, Deshmukh US, Fu SM, Ju ST The CD25(+)Foxp3(+) regulatory T-cells (Treg) that had lost CD25 and Foxp3 in vivo (ex-Treg) exist but are difficult to study. We generated antigen (Ag)-specific Treg hybridomas from iTreg clones (iTreg-hyb) using iTreg of DO11.10.Foxp3-GFP mice and presented evidence that they behave like ex-Treg. The iTreg-hyb displayed little CD25 and Foxp3-GFP but strong expression could be induced with OVA(323-339) in the presence of Ag-presenting cells, rIL-2 and rTGF-β1. They displayed all of the iTreg-associated markers examined except CTLA-4, the latter was also absent in the ex-Treg. They lacked the Helios transcription factor, suggesting they were derived from iTreg. Similar to ex-Treg, the iTreg-hyb produced high level of IL-2 and Foxp3 under specific activation conditions. Two unusual properties were observed. First, the ability to induce Foxp3-GFP upon activation is progressively lost in culture over a period of 2-4 weeks. Second, Rag2(-/-) spleen cells alone selectively induced Foxp3-GFP expression albeit 30 times less efficient than Ag-specific activation. We identified cell-free supernatant, IL-6, IL-9, and IL-27 as Foxp3-inducing factors. Our study has significant implications to the stability, plasticity and fate of Treg. The usefulness and limitation of iTreg-hyb as a novel tool to study Foxp3 regulation and the fate of specific Treg subsets are discussed. PMID: 21621978 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Na+, K+-ATPase genes are down-regulated during adipose stem cell differentiation. Front Biosci (Elite Ed). 2011;3:1229-1240 Authors: Acosta E, Avila J, Mobasheri A, Martin-Vasallo P The expression of Na+, K+-ATPase alpha and beta subunits isoforms, FXYD2 and FXYD7 were studied in rat adipose stem cell (ASC) by qRT-PCR and immunofluorescence. ASCs were able to differentiate to chondrocytes or adipocytes. All studied genes were expressed in freshly isolated ASCs and in all passages checked. Immunostaining for alpha1 isoform was found in plasma membrane and nuclear envelope, alpha2 signal was lower and alpha3 staining was variable among cells. Beta isoforms signal was abundant and displayed an isoform-specific picture. Staining for FXYD7 was homogeneous in plasma membrane and cytosol. Chondrocytes differenciated from ASC showed identical Na+, K+-ATPase subunits isoforms expression patterns to chondrocytes in cartilage. The expression pattern of Na+, K+-ATPase genes in ASCs exhibits a unique phenotypic signature that implies functional differences in Na+ and K+ transport rates. Furthermore, this phenotypic signature may also be used as a complementary marker for studies of mesenchymal stem cell differentiation. We propose a possible 'moonlighting' role of Na+, K+-ATPase beta isoforms that could be essential for the study of mesenchymal stem cell function and differentiation. PMID: 21622129 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Strategies in Functional Poly(ester amide) Syntheses to Study Human Coronary Artery Smooth Muscle Cell Interactions. Biomacromolecules. 2011 May 30; Authors: Knight DK, Gillies ER, Mequanint K The design of new generation cardiovascular biomaterials focuses on biomimetic properties that are capable of eliciting specific cellular responses and directing new tissue formation. Synthetic poly(ester amide)s (PEAs) containing α-amino acid residues have the potential to elicit favorable cellular responses. Furthermore, they are biodegradable owing to the incorporation of naturally occurring amino acids. In this study, a family of PEAs was synthesized from selected α-amino acids using both solution and interfacial polymerization approaches to optimize their properties for vascular tissue engineering applications. By careful selection of the monomers and the polymerization approach, high molecular weight PEAs with low glass transition temperatures were obtained. Human coronary artery smooth muscle cells (HCASMCs) cultured directly on bare PEA films attached and spread well up to 7 days of culture. Moreover, cell viability was significantly enhanced on all non-functional PEAs compared with tissue culture polystyrene controls. The trifluoroacetic acid salt of the lysine-containing functional PEAs was found to retard cell growth, but still supported cell viability up to 5 days of culture. Immunostaining of HCASMCs revealed strong vinculin expression suggesting that the HCASMCs initiated cellular processes for focal adhesion contacts with all PEA surfaces. Conversely, smooth muscle α-actin expression was not abundant on the PEA surfaces suggesting a proliferative smooth muscle cell phenotype. Altogether, our results indicate that these PEAs are promising materials for vascular tissue engineering scaffolds. PMID: 21619072 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The influence of substrate creep on mesenchymal stem cell behaviour and phenotype. Biomaterials. 2011 May 27; Authors: Cameron AR, Frith JE, Cooper-White JJ Human mesenchymal stem cells (hMSCs) are capable of probing and responding to the mechanical properties of their substrate. Although most biological and synthetic matrices are viscoelastic materials, previous studies have primarily focused upon substrate compressive modulus (rigidity), neglecting the relative contributions that the storage (elastic) and loss (viscous) moduli make to the summed compressive modulus. In this study we aimed to isolate and identify the effects of the viscous component of a substrate on hMSC behaviour. Using a polyacrlyamide gel system with constant compressive modulus and varying loss modulus we determined that changes to substrate loss modulus substantially affected hMSC morphology, proliferation and differentiation potential. In addition, we showed that the effect of substrate loss modulus on hMSC behaviour is due to a reduction in both passive and actively generated isometric cytoskeletal tension caused by the inherent creep of substrates with a high loss modulus. These findings highlight substrate creep, or more explicitly substrate loss modulus, as an important mechanical property of a biomaterial system that can be tailored to encourage the growth and differentiation of specific cell types. PMID: 21621838 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Characterization of the Physical Properties and Biocompatibility of Polybenzoxazine-Based Aerogels for Use as a Novel Hard-Tissue Scaffold. J Biomater Sci Polym Ed. 2011 May 27; Authors: Rubenstein DA, Lu H, Mahadik SS, Leventis N, Yin W The process to successfully synthesize polybenzoxazine (PBO)-based aerogels has recently been optimized; however, the biocompatibility of these materials has never been investigated. PBO is synthesized from bisphenol A and aniline, which are both precursors to many commonly used biomaterials, including polyurethane. Surface-wise these new aerogels resemble the innate extracellular matrix of bone and if these new aerogels exhibit acceptable biocompatibility, they may be used as a scaffold for bone tissue engineering. Here, we aimed to characterize some of the physical properties of PBO aerogels, PBO aerogels co-polymerized with resorcinol and formaldehyde (RF) and their conversion to carbon aerogel, while determining the compatibility of all of these materials towards human osteoblasts. Biocompatibility was determined with a live/dead cell cytotoxicity assay, a metabolic activity assay, alkaline phosphatase activity and osteocalcin production, after incubation with PBO-based aerogels for up to 5 days. PBO aerogels co-polymerized with RF tended to have a low density, porosity and elastic modulus and provided the weakest substrate for bone cell growth. PBO-derived carbon aerogels tended to have a high density, a large porosity and improved mechanical properties and provided the best substrate for bone cell growth. These results suggest that PBO based carbon aerogels have a suitable biocompatibility towards osteoblasts and that they may be able to be used for bone tissue engineering scaffolds. PMID: 21619731 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The impact of VEGF and bFGF on vascular stereomorphology in the context of angiogenic neo-arborisation after vascular induction. J Electron Microsc (Tokyo). 2011 May 28; Authors: Polykandriotis E, Arkudas A, Beier JP, Dragu A, Rath S, Pryymachuk G, Schmidt VJ, Lametschwandtner A, Horch RE, Kneser U The aim of this in vivo study was to gather quantitative information on the three-dimensional morphology of a new vascular network under the influence of angioactive growth factors. For this purpose, the arteriovenous loop model was used in 10 Lewis rats to generate a bioartificial vascular assembly by means of vascular induction. In this model, an isolated organoid is created in the medial thigh of the animal by methods of tissue engineering. A fibrin gel containing vascular endothelial growth factor (VEGF(165)) and basic fibroblastic growth factor (bFGF) was used as a matrix in the effect group (GF+). Fibrin matrices devoid of growth factors were used as controls (GF-). A microvascular replica of the organoid was created by means of corrosion casting and the network was investigated on stereo-paired images obtained by scanning electron microscopy. Vectors of intercapillary and interbranching distances as well as the diameter of the pores in the intussusceptive events diameter and the ratio of sprouting versus intussusceptive angiogenic events were compared in the two groups. The results were highly significant. In the GF+ group there were more profound three-dimensional morphological traits of angiogenesis, whereas advanced neovascularisation in the phase of remodelling was demonstrated by a higher incidence of intussusception, compared to control. These results illustrate the importance of morphological studies with focus on the generation of three-dimensional vascular networks. PMID: 21622976 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cells cardiac differentiation in 3D systems. Front Biosci (Schol Ed). 2011;3:901-918 Authors: Spadaccio C, Rainer A, Chachques JC, Covino E, Herreros J, Genovese JA Cardiac regeneration requires a complex cascade of events. Stem cell therapy and tissue engineering are newly emerging tools with promising potential for recover or replace of damaged cardiac tissue. There are many factors, most of them still no clarified, that limit the effectiveness of these treatments and their translation to the clinic. Cells should graft, survive and functionally integrate to the target organ in order to have a chance to restore its function. As in original tissues, a complex and well defined set of signals, many of them coming from the extracellular matrix, is required for normal cell physiology. Biomaterials science gives us important tools to build this extracellular matrix. Functionalized 3D systems can provide the correct environment and act as a delivery system for genes or gene products, guiding the therapeutic cells to the functional phenotype. PMID: 21622240 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The liquid overlay technique is the key to formation of co-culture spheroids consisting of primary osteoblasts, fibroblasts and endothelial cells. Cytotherapy. 2011 May 27; Authors: Metzger W, Sossong D, Bächle A, Pütz N, Wennemuth G, Pohlemann T, Oberringer M Abstract Background aims. The 3-dimensional (3-D) culture of various cell types reflects the in vivo situation more precisely than 2-dimensional (2-D) cell culture techniques. Spheroids as 3-D cell constructs have been used in tumor research for a long time. They have also been used to study angiogenic mechanisms, which are essential for the success of many tissue-engineering approaches. Several methods of forming spheroids are known, but there is a lack of systematic studies evaluating the performance of these techniques. Methods. We evaluated the performance of the hanging drop technique, carboxymethyl cellulose technique and liquid overlay technique to form both mono- and co-culture spheroids consisting of primary osteoblasts, fibroblasts and endothelial cells. The performance of the three techniques was evaluated in terms of rate of yield and reproducibility. The size of the generated spheroids was determined systematically. Results. The liquid overlay technique was the most suitable for generating spheroids reproducibly. The rate of yield for this technique was between 60% and 100% for monoculture spheroids and 100% for co-culture spheroids. The size of the spheroids could be adjusted easily and precisely by varying the number of seeded cells organized in one spheroid. The formation of co-culture spheroids consisting of three different cell types was possible. Conclusions. Our results show that the most suitable technique for forming spheroids can vary from the chosen cell type, especially if primary cells are used. Co-culture spheroids consisting of three different cell types will be used to study angiogenic phenomena in further studies. PMID: 21619419 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Molecular simulations predict novel collagen conformations during cross-link loading. Matrix Biol. 2011 May 25; Authors: Bourne JW, Torzilli PA Collagen cross-linking mechanically strengthens tissues during development and aging, but there is limited data describing how force transmitted across cross-links affects molecular conformation. We used Steered Molecular Dynamics (SMD) to model perpendicular force through a side chain. Results predicted that collagen peptides have negligible bending resistance and that mechanical force causes helix disruption below covalent bond failure strength, suggesting alternative molecular conformations precede cross-link rupture and macroscopic damage during mechanical loading. PMID: 21620686 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Differential modulation of stress-inflammation responses by plant polyphenols in cultured normal human keratinocytes and immortalized HaCaT cells. J Dermatol Sci. 2011 May 8; Authors: Pastore S, Lulli D, Potapovich AI, Fidanza P, Kostyuk VA, Dellambra E, De Luca C, Maurelli R, Korkina LG BACKGROUND: Environmental and endogenous stresses to skin are considered causative reasons for skin cancers, premature ageing, and chronic inflammation. Screening of substances with preventive and/or curative properties is currently based on mechanistic studies of their effects towards stress-induced responses in skin cell cultures. OBJECTIVE: We compared effects of plant polyphenols (PPs) on the constitutive, UVA-, LPS-, or TNF-alpha-induced inflammatory responses in cultured normal human epidermal keratinocytes (NHEK) and immortalized HaCaT cells. METHODS: Representatives of three classes of PPs, flavonoids, stilbenoids, and phenylpropanoids were studied. Their effects on mRNA were determined by qRT-PCR; protein expression was assayed by Western blot and bioplexed ELISA; phosphorylation of Akt1, ERK1/2, EGFR, and NFkappaB was quantified by intracellular ELISA or Western blot. RESULTS: PPs or their combination with UVA or LPS induced strong up-regulation of stress responses in HaCaT but not in NHEK. In addition, compared to NHEK, HaCaT responded to TNF-alpha with higher synthesis of MCP-1, IP-10 and IL-8, concomitant with stronger NFkappaB activation. PPs down-regulated the chemokine release from both cell types, although with distinct effects on NFkappaB, Akt1, ERK, and EGFR activation. CONCLUSION: Results of pharmacological screenings obtained by using HaCaT should be cautiously considered while extending them to primary keratinocytes from human epidermis. PMID: 21620684 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Regenerative medicine and tissue engineering in orthopaedic surgery. Front Biosci (Elite Ed). 2011;3:923-944 Authors: Ivkovic A, Marijanovic I, Hudetz D, Porter RM, Pecina M, Evans CH Orthopedic surgery is going through a serious paradigm shift; instead of simply replacing damaged tissues with prosthetic or allograft material, the aim is to regenerate them. This endeavor has generated the field of regenerative orthopaedics, an increasingly expanding area of research with hopes of providing new and better treatments for diseases and injuries affecting the musculoskeletal system. As part of this process, we are witnessing a substantial accumulation of new cellular and molecular insights into connective tissue function, coupled with emerging new concepts in stem cell biology and scaffolding technologies. Indeed, any successful strategy to regenerate musculoskeletal tissues can be portrayed as an intricate interplay between the three main constituents of the regenerative system: cells, environment and scaffolds. This review is not meant to be exhaustive and comprehensive, but aims to highlight concepts and key advances in the field of regenerative orthopaedics and tissue engineering, as well as to present current possibilities for clinical translation. PMID: 21622102 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Monitoring human mesenchymal stromal cell differentiation by electrochemical impedance sensing. Cytotherapy. 2011 May 30; Authors: Angstmann M, Brinkmann I, Bieback K, Breitkreutz D, Maercker C Abstract Background aims. For their wide mesodermal differentiation potential, mesenchymal stromal/stem cells (MSC) are attractive candidates for tissue engineering. However, standardized quality control assays monitoring differentiation that are non-invasive and continuous over time are lacking. Methods. We employed a non-invasive assay, using two different systems, to discriminate osteogenic and adipogenic differentiation of MSC by monitoring impedance. Fibroblasts and keratinocytes served as non-specific controls. Impedance profiles were recorded comparing MSC from bone marrow and adipose tissue, either non-induced or induced for osteogenesis or adipogenesis, for 5-14 days, and correlated with differentiation markers assessed by reverse transcription-quantitative polymerase chain reaction and Western blot. Additionally, differentiation modulating effects of extracellular matrix components were analyzed. Results. Adhesion and growth-related impedance profiles of non-induced MSC roughly resembled those of fibroblasts, whereas keratinocytes differed significantly. Distinct from that, osteogenic induction of MSC revealed initially rapid and continuously rising impedance, corresponding to mineralized calcium matrix formation. Conversely, adipogenic induction caused shallower initial slopes and eventually declining profiles, corresponding to more compact, adipocyte-like cells with numerous lipid vacuoles. Pre-coating with either collagen type I or IV apparently favored osteogenesis and fibronectin adipogenesis. Impedance recordings correlated well with the extent of differentiation evaluated by histochemical staining and protein and gene expression. Conclusions. Overall, our data demonstrate that impedance profiling offers a basis for standardized real-time, non-invasive high-throughput screening of MSC properties. It enables further testing of the influence of diffusible factors or extracellular matrix composites on MSC differentiation or maintenance of stemness, thus substantiating therapeutic application. PMID: 21619493 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Pro-osteogenic trophic effects by PKA activation in human mesenchymal stromal cells. Biomaterials. 2011 May 27; Authors: Doorn J, van de Peppel J, van Leeu JP, Groen N, van Blitterswijk CA, de Boer J Human mesenchymal stromal cells (hMSCs) are able to differentiate into a wide variety of cell types, which makes them an interesting source for tissue engineering applications. On the other hand, these cells also secrete a broad panel of growth factors and cytokines that can exert trophic effects on surrounding tissues. In bone tissue engineering applications, the general assumption is that direct differentiation of hMSCs into osteoblasts accounts for newly observed bone formation in vivo. However, the secretion of bone-specific growth factors, but also pro-angiogenic factors, could also contribute to this process. We recently demonstrated that secretion of bone specific growth factors can be enhanced by treatment of hMSCs with the small molecule db-cAMP (cAMP) and here we investigate the biological activity of these secreted factors. We demonstrate that conditioned medium contains a variety of secreted growth factors, with differences between medium from basic-treated and cAMP-treated hMSCs. We show that conditioned medium from cAMP-treated hMSCs increases proliferation of various cell types and also induces osteogenic differentiation, whereas it has differential effects on migration. Microarray analysis on hMSCs exposed to conditioned medium confirmed upregulation of pathways involved in proliferation as well as osteogenic differentiation. Our data suggests that trophic factors secreted by hMSCs can be tuned for specific applications and that a good balance between differentiation on the one hand and secretion of bone trophic factors on the other, could potentially enhance bone formation for bone tissue engineering applications. PMID: 21621835 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | Drawing nearly all the attention nowadays at the California stem cell agency is selection of a new chairman, but real work is also going on.
That is not to underestimate the importance of the decision, but the trains still have to keep running at CIRM headquarters in San Francisco.
Next Monday, for example, the directors' Science Subcommittee will meet to consider matters that all potential | | | | | | | | | |  | |  | |  |
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