|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Proteomics-based signature for human benign prostate hyperplasia and prostate adenocarcinoma. Int J Oncol. 2011 Feb 8; Authors: Alaiya AA, Al-Mohanna M, Aslam M, Shinwari Z, Al-Mansouri L, Al-Rodayan M, Al-Eid M, Ahmad I, Hanash K, Tulbah A, Mahfooz AB, Adra C Prostate adenocarcinoma often presents at a late stage, due to a lack of early clinical symptoms and lack of accurate objective markers. This study aimed to identify and validate proteomics-based biomarkers useful for prostate cancer diagnosis and to establish a marker-panel for prostate cancer and benign prostate hyperplasia (BPH). Global protein expression patterns in fresh tissue specimens from 8 patients with prostate carcinoma and 16 with BPH were analyzed by two-dimensional gel electrophoresis. Differentially expressed proteins were identified by MALDI-TOF mass spectrometry. We compared our results with those of published studies and defined a set of common biomarkers. We identified 22 differentially expressed proteins between BPH and prostate carcinomas. The up-regulated proteins in cancer compared to BPH included protein disulfide-isomerase, 14-3-3-protein, Enoyl CoA-hydrase, prohibitin and B-tubulin β-2. Keratin-II, desmin, HSP71, ATP-synthase-β-chain and creatine kinase-β-chain were down-regulated. Survey of the literature showed that 15 of our 22 identified proteins have been previously reported to differ in their expression levels between BPH and prostate cancer by other laboratories. The expression patterns of these biomarkers could successfully cluster BPH and adenocarcinomas as well as prostate cancer of low and high Gleason scores. This study validates protein-biomarkers that can be useful for accurate diagnosis and prognostic monitoring of prostate adenocarcinoma. Despite varied prevalence of the disease between different ethnic populations (i.e., high in Sweden, low in Saudi Arabia); the biomarkers indicate that BPH and prostate cancers are biologically 'homogeneous' in their protein expression patterns across wide geographical regions. PMID: 21305254 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Safety of intravenous infusion of human adipose tissue-derived mesenchymal stem cells in animals and humans. Stem Cells Dev. 2011 Feb 8; Authors: Ra JC, Shin IS, Kim SH, Kang SK, Kang BC, Lee HY, Kim YJ, Jo JY, Yoon EJ, Choi HJ, Kwon E Adipose tissue-derived mesenchymal stem cells (AdMSCs) represent an attractive and ethical cell source for stem cell therapy. With the recent demonstration of MSC homing properties, intravenous applications of MSCs to cell-damaged diseases have increased. In the present study, the toxicity and tumorigenicity of human AdMSCs (hAdMSCs) were investigated for clinical application. Culture-expanded hAdMSCs showed the typical appearance, immunophenotype and differentiation capacity of MSCs, and were genetically stable at least 12 passages in culture. Cells suspended in physiological saline maintained their MSC properties in a cold storage condition for at least 3 d. To test the toxicity of hAdMSCs, different doses of hAdMSCs were injected intravenously into immunodeficient mice, and the mice were observed for 13 weeks. Even at the highest cell dose (2.5×108 cells/kg body weight), the SCID mice were viable and had no side effects. A tumorigenicity test was performed in Balb/c-nu nude mice for 26 weeks. Even at the highest cell dose (2×108 MSCs/kg), no evidence of tumor development was found. In a human clinical trial, eight male patients who had suffered a spinal cord injury more than 12 months previous were intravenously administered autologous hAdMSCs (4×108 cells) one time. None of the patients developed any serious adverse events related to hAdMSC transplantation during the 3-month follow-up. In conclusion, the systemic transplantation of hAdMSCs appears to be safe and does not induce tumor development. PMID: 21303266 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | Looking for a roundup on stem cell firms and their activities? You can find a brief one on the blog of a stem cell scientist at UC Davis.
In a piece called "stem cell biotech updates," Paul Knoepfler mentions the surprise departure of Tom Okarma as president of Geron Corp. of Menlo Park, Ca., declaring that it means a "fundamental change" at the firm.
On the same subject elsewhere, Rob | | | | | | | | | | | | | | | | | | | | | | | | | Loss of pten causes tumor initiation following differentiation of murine pluripotent stem cells due to failed repression of nanog. PLoS One. 2011;6(1):e16478 Authors: Lindgren AG, Natsuhara K, Tian E, Vincent JJ, Li X, Jiao J, Wu H, Banerjee U, Clark AT Pluripotent stem cells (PSCs) hold significant promise in regenerative medicine due to their unlimited capacity for self-renewal and potential to differentiate into every cell type in the body. One major barrier to the use of PSCs is their potential risk for tumor initiation following differentiation and transplantation in vivo. In the current study we sought to evaluate the role of the tumor suppressor Pten in murine PSC neoplastic progression. Using eight functional assays that have previously been used to indicate PSC adaptation or transformation, Pten null embryonic stem cells (ESCs) failed to rate as significant in five of them. Instead, our data demonstrate that the loss of Pten causes the emergence of a small number of aggressive, teratoma-initiating embryonic carcinoma cells (ECCs) during differentiation in vitro, while the remaining 90-95% of differentiated cells are non-tumorigenic. Furthermore, our data show that the mechanism by which Pten null ECCs emerge in vitro and cause tumors in vivo is through increased survival and self-renewal, due to failed repression of the transcription factor Nanog. PMID: 21304588 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Prolonged Upright Posture Induces Calcified Hypertrophy in the Cartilage End-plate in Rat Lumbar Spine. Spine (Phila Pa 1976). 2011 Feb 7; Authors: Bian Q, Liang QQ, Wan C, Hou W, Li CG, Zhao YJ, Lu S, Shi Q, Wang YJ ABSTRACT: Study Design. Both forelimbs of rats were amputated and these rats were kept in the custom-made cages to keep prolonged and repeated upright posture. Changes of bone were observed in the lumbar vertebrae at three different time points after the surgery.Objective. To investigate the effect of prolonged and repeated upright posture on the cartilage end-plate of rat lumbar vertebrae.Summary of Background Data. Previous studies show calcified hypertrophy is related to mechanical stress, but there are no clear evidences to indicate whether or not long-term and repeated assumption of the upright posture could result in calcified hypertrophy in cartilage end-plate of rat lumbar spine.Methods. The forelimbs of 30 rats were amputated when they were 1 month old. These rats were kept in the custom-made cages and were forced to stand upright on their hind-limbs and tails to obtain water and food. Normal rats of the same ages kept in regular cages were used as control. The rats were sacrificed at 5, 7, and 9 months after the surgery and lumbar vertebrae samples were harvested for micro-CT, histological and immunohistochemical studies. Total RNA isolated from these samples were used for real time RT-PCR of type X collagen (Col10α1), vascular endothelial growth factor (VEGF) and transforming growth factor β1 (TGF-β1).Results. Micro-CT showed increased inner part of cartilage end-plate. Histological revealed peripheral hypertrophy of disc following the surgery. Immunostaining and real time RT-PCR showed increased protein and mRNA expression of type X collagen, VEGF and TGF-β1.Conclusion. Prolonged upright posture induces cartilage end-plate calcification and hypertrophy in rat lumbar spine. PMID: 21304433 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Genetic modeling of gliomas in mice: New tools to tackle old problems. Glia. 2011 Feb 8; Authors: Hambardzumyan D, Parada LF, Holland EC, Charest A The recently published comprehensive profiles of genomic alterations in glioma have led to a refinement in our understanding of the molecular events that underlie this cancer. Using state-of-the-art genomic tools, several laboratories have created and characterized accurate genetically engineered mouse models of glioma based on specific genetic alterations observed in human tumors. These in vivo brain tumor models faithfully recapitulate the histopathology, etiology, and biology of gliomas and provide an exceptional experimental system to discover novel therapeutic targets and test therapeutic agents. This review focuses on mouse models of glioma with a special emphasis on genetically engineered models developed around key genetic glioma signature mutations in the PDGFR, EGFR, and NF1 genes and pathways. The resulting animal models have provided insight into many fundamental and mechanistic facets of tumor initiation, maintenance and resistance to therapeutic intervention and will continue to do so in the future. © 2011 Wiley-Liss, Inc. PMID: 21305617 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Adipose Derived Stromal Cells for Skeletal Regenerative Medicine. Stem Cells. 2011 Feb 8; Authors: Levi B, Longaker MT As the average age of the population grows, the incidence of osteoporosis and skeletal diseases continues to rise. Current treatment options for skeletal repair include immobilization, rigid fixation, alloplastic materials and bone grafts, all which have significant limitations, especially in the elderly. Adipose derived stromal cells (ASCs) represent a readily available abundant supply of mesenchymal stem cells which demonstrate the ability to undergo osteogenesis in vitro and in vivo, making ASCs a promising source of skeletal progenitor cells. Current protocols allow for the harvest of over 1 million cells from only 15cc of lipoaspirate. Despite the clinical use of ASCs to treat systemic inflammatory diseases, no large human clinical trials exist using ASCs for skeletal tissue engineering. The aim of this review is to define ASCs, to describe the isolation procedure of ASCs, to review the basic biology of their osteogenic differentiation, discuss cell types and scaffolds available for bone tissue engineering and lastly to explore imaging of ASCs and their potential future role in human skeletal tissue engineering efforts. PMID: 21305671 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Telomerase reactivation reverses tissue degeneration in aged telomerase-deficient mice. Nature. 2011 Jan 6;469(7328):102-6 Authors: Jaskelioff M, Muller FL, Paik JH, Thomas E, Jiang S, Adams AC, Sahin E, Kost-Alimova M, Protopopov A, Cadiñanos J, Horner JW, Maratos-Flier E, Depinho RA An ageing world population has fuelled interest in regenerative remedies that may stem declining organ function and maintain fitness. Unanswered is whether elimination of intrinsic instigators driving age-associated degeneration can reverse, as opposed to simply arrest, various afflictions of the aged. Such instigators include progressively damaged genomes. Telomerase-deficient mice have served as a model system to study the adverse cellular and organismal consequences of wide-spread endogenous DNA damage signalling activation in vivo. Telomere loss and uncapping provokes progressive tissue atrophy, stem cell depletion, organ system failure and impaired tissue injury responses. Here, we sought to determine whether entrenched multi-system degeneration in adult mice with severe telomere dysfunction can be halted or possibly reversed by reactivation of endogenous telomerase activity. To this end, we engineered a knock-in allele encoding a 4-hydroxytamoxifen (4-OHT)-inducible telomerase reverse transcriptase-oestrogen receptor (TERT-ER) under transcriptional control of the endogenous TERT promoter. Homozygous TERT-ER mice have short dysfunctional telomeres and sustain increased DNA damage signalling and classical degenerative phenotypes upon successive generational matings and advancing age. Telomerase reactivation in such late generation TERT-ER mice extends telomeres, reduces DNA damage signalling and associated cellular checkpoint responses, allows resumption of proliferation in quiescent cultures, and eliminates degenerative phenotypes across multiple organs including testes, spleens and intestines. Notably, somatic telomerase reactivation reversed neurodegeneration with restoration of proliferating Sox2(+) neural progenitors, Dcx(+) newborn neurons, and Olig2(+) oligodendrocyte populations. Consistent with the integral role of subventricular zone neural progenitors in generation and maintenance of olfactory bulb interneurons, this wave of telomerase-dependent neurogenesis resulted in alleviation of hyposmia and recovery of innate olfactory avoidance responses. Accumulating evidence implicating telomere damage as a driver of age-associated organ decline and disease risk and the marked reversal of systemic degenerative phenotypes in adult mice observed here support the development of regenerative strategies designed to restore telomere integrity. PMID: 21113150 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Mechanical properties and in vivo behavior of a biodegradable synthetic polymer microfiber-extracellular matrix hydrogel biohybrid scaffold. Biomaterials. 2011 Feb 6; Authors: Hong Y, Huber A, Takanari K, Amoroso NJ, Hashizume R, Badylak SF, Wagner WR A biohybrid composite consisting of extracellular matrix (ECM) gel from porcine dermal tissue and biodegradable elastomeric fibers was generated and evaluated for soft tissue applications. ECM gel possesses attractive biocompatibility and bioactivity with weak mechanical properties and rapid degradation, while electrospun biodegradable poly(ester urethane)urea (PEUU) has good mechanical properties but limited cellular infiltration and tissue integration. A concurrent gel electrospray/polymer electrospinning method was employed to create ECM gel/PEUU fiber composites with attractive mechanical properties, including high flexibility and strength. Electron microscopy revealed a structure of interconnected fibrous layers embedded in ECM gel. Tensile mechanical properties could be tuned by altering the PEUU/ECM weight ratio. Scaffold tensile strengths for PEUU/ECM ratios of 67/33, 72/28 and 80/20 ranged from 80 to 187 kPa in the longitudinal axis (parallel to the collecting mandrel axis) and 41-91 kPa in the circumferential axis with 645-938% breaking strains. The 72/28 biohybrid composite and a control scaffold generated from electrospun PEUU alone were implanted into Lewis rats, replacing a full-thickness abdominal wall defect. At 4 wk, no infection or herniation was found at the implant site. Histological staining showed extensive cellular infiltration into the biohybrid scaffold with the newly developed tissue well integrated with the native periphery, while minimal cellular ingress into the electrospun PEUU scaffold was observed. Mechanical testing of explanted constructs showed evidence of substantial remodeling, with composite scaffolds adopting properties more comparable to the native abdominal wall. The described elastic biohybrid material imparts features of ECM gel bioactivity with PEUU strength and handling to provide a promising composite biomaterial for soft tissue repair and replacement. PMID: 21303718 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Activating Signals Dominate Inhibitory Signals in CD137L/IL-15 Activated Natural Killer Cells. J Immunother. 2011 Feb 7; Authors: Zhang H, Cui Y, Hawk NV, Sabatino M, Stroncek DF, Morisot S, Civin CI, Wayne AS, Levine BL, Mackall CL Natural killer (NK) cells can mediate potent antitumor effects, but factors regulating the efficiency of tumor lysis remain unclear. Studies in allogeneic stem cell transplantation highlight an important role for killer cell immunoglobulin-like receptor (KIR) mismatch in overcoming human leukocyte antigen-mediated inhibitory signals. However, other activating and inhibitory signals also modulate tumor lysis by NK cells. We used rhIL15 and artificial antigen presenting cells expressing CD137L and IL15Rα to activate and expand peripheral blood NK cells (CD137L/IL15 NK) up to 1000-fold in 3 weeks. Compared with resting NK cells, CD137L/IL15 NK cells show modest increases in KIR expression and substantial increases in NKG2D, tumor necrosis factor-related apoptosis-inducing ligand, and natural cytotoxicity receptors (NCRs: NKp30, NKp44, NKp46). Compared with resting NK cells, CD137L/IL15 NK cells mediate enhanced cytotoxicity against allogeneic and autologous tumors and KIR signaling did not substantially inhibit cytotoxicity. Rather, tumor lysis by CD137L/IL15 activated NK cells was predominantly driven by NCR signaling as blockade of NCRs dramatically diminished the lysis of a wide array of tumor targets. Furthermore, tumor lysis by CD137L/IL15 NK cells was tightly linked to NCR expression levels that peaked on day 8 to 10 after NK activation, and cytotoxicity diminished on subsequent days as NCR expression declined. We conclude that KIR mismatch is not a prerequisite for tumor killing by CD137L/IL15 NK cells and that NCR expression provides a biomarker for predicting potency of CD137L/IL15 NK cells in studies of NK cell-based immunotherapy. PMID: 21304401 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Biodegradable and Biocompatible Synthetic Saccharide-Peptide Hydrogels for Three-Dimensional Stem Cell Culture. Biomacromolecules. 2011 Feb 8; Authors: Chawla K, Yu TB, Liao SW, Guan Z Saccharide-peptide hydrogels have been developed in our laboratory as new synthetic extracellular matrices for regenerative medicine applications. In this work, we have expanded on our previously reported system and applied copolymerization of cysteine (Cys) and vinyl sulfone (VS)-functionalized saccharide-peptide polymers via Michael-type addition for encapsulation and 3D culture of cells. Specifically, our aims were to (1) develop a novel hydrogel platform, which could be applied for encapsulating and culturing mesenchymal stem cells (MSCs) in a 3D environment, (2) characterize the tunable properties of the hydrogel, specifically, degradation, mechanical, and gel network properties, and (3) determine the biocompatibility of the saccharide-peptide hydrogel material with MSCs. Hydrogel mechanical properties were tunable by varying the VS:Cys ratio (= 0.5, 1, or 2) as well as the pH (6, 7, or 8) of the cross-linking components. Stiffer gels were formed at VS:Cys = 1 and pH 6 or 7. Gels formed at pH 8 or with excess Cys (VS:Cys = 0.5) or VS (VS:Cys = 2) were significantly softer. Cross-linking pH and VS:Cys ratio also had an effect on the degradation behavior of the VS:Cys gels, with higher cross-linking pH resulting in an accelerated loss of mass. On the basis of environmental scanning electron microscopy (ESEM) analysis and fluorescence microscopy, all hydrogels appeared to exhibit porous gel networks. MSCs cultured in monolayer and exposed to soluble Cys or VS copolymers (0.1-5 mg/mL) did not exhibit measurable cytotoxicity. In addition, MSCs were cultured in 3D for up to 14 days in vitro without deleterious effects on cell viability. In summary, we have established and characterized a tunable 3D saccharide-peptide hybrid copolymer hydrogel platform for culturing MSCs. Future studies will focus on utilizing the hydrogel system for controlling the differentiation of MSCs. PMID: 21302962 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Local vascularized flaps for augmentation of reinke's space. Laryngoscope. 2011 Feb;121 Suppl 3:S37-60 Authors: Dailey SH, Gunderson M, Chan R, Torrealba J, Kimura M, Welham NV The purpose of this study is to describe and test a novel surgical strategy for augmentation of Reinke's space using vascularized flaps: a thyroid ala perichondrium flap (TAP) and a composite thyroid ala perichondrium flap (CTAP) from the anterior larynx. We hypothesized that these specially designed vascularized flaps would remain viable once inset into the lamina propria, and that they would not disrupt rheologic, biomechanical, and histologic properties of the native vocal fold. PMID: 21271606 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Pectin-Based Injectable Biomaterials for Bone Tissue Engineering. Biomacromolecules. 2011 Feb 8; Authors: Munarin F, Guerreiro SG, Grellier MA, Tanzi MC, Barbosa MA, Petrini P, Granja PL A variety of natural polymers and proteins are considered to be 3D cell culture structures able to mimic the extracellular matrix (ECM) to promote bone tissue regeneration. Pectin, a natural polysaccharide extracted from the plant cell walls and having a chemical structure similar to alginate, provides interesting properties as artificial ECM. In this work, for the first time, pectin, modified with an RGD-containing oligopeptide or not, is used as an ECM alternative to immobilize cells for bone tissue regeneration. The viability, metabolic activity, morphology, and osteogenic differentiation of immobilized MC3T3-E1 preosteoblats demonstrate the potential of this polysaccharide to keep immobilized cells viable and differentiating. Preosteoblasts immobilized in both types of pectin microspheres maintained a constant viability up to 29 days and were able to differentiate. The grafting of the RGD peptide on pectin backbone induced improved cell adhesion and proliferation within the microspheres. Furthermore, not only did cells grow inside but also they were able to spread out from the microspheres and to organize themselves in 3D structures producing a mineralized extracellular matrix. These promising results suggest that pectin can be proposed as an injectable cell vehicle for bone tissue regeneration. PMID: 21302960 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The role of vascular actors in two dimensional dialogue of human bone marrow stromal cell and endothelial cell for inducing self-assembled network. PLoS One. 2011;6(2):e16767 Authors: Li H, Daculsi R, Grellier M, Bareille R, Bourget C, Remy M, Amedee J Angiogenesis is very important for vascularized tissue engineering. In this study, we found that a two-dimensional co-culture of human bone marrow stromal cell (HBMSC) and human umbical vein endothelial cell (HUVEC) is able to stimulate the migration of co-cultured HUVEC and induce self-assembled network formation. During this process, expression of vascular endothelial growth factor (VEGF(165)) was upregulated in co-cultured HBMSC. Meanwhile, VEGF(165)-receptor2 (KDR) and urokinase-type plasminogen activator (uPA) were upregulated in co-cultured HUVEC. Functional studies show that neutralization of VEGF(165) blocked the migration and the rearrangement of the cells and downregulated the expression of uPA and its receptor. Blocking of vascular endothelial-cadherin (VE-cad) did not affect the migration of co-cultured HUVEC but suppressed the self-assembled network formation. In conclusion, co-cultures upregulated the expression of VEGF(165) in co-cultured HBMSC; VEGF(165) then activated uPA in co-cultured HUVEC, which might be responsible for initiating the migration and the self-assembled network formation with the participation of VE-cad. All of these results indicated that only the direct contact of HBMSC and HUVEC and their respective dialogue are sufficient to stimulate secretion of soluble factors and to activate molecules that are critical for self-assembled network formation which show a great application potential for vascularization in tissue engineering. PMID: 21304816 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Enhancing bone formation by transplantation of a scaffold-free tissue-engineered periosteum in a rabbit model. Clin Oral Implants Res. 2011 Feb 8; Authors: Ma D, Yao H, Tian W, Chen F, Liu Y, Mao T, Ren L Objectives: The periosteum plays an important role in bone regeneration. However, the harvesting of autogenous periosteum is associated with disadvantages such as donor site morbidity and limited donor sources. This study uses an osteogenic predifferentiated cell sheet to fabricate a scaffold-free tissue-engineered periosteum (TEP). Material and methods: We generated an osteogenic predifferentiated cell sheet from rabbit bone marrow stromal cells (BMSCs) using a continuous culture system and harvested it using a scraping technique. Then, the in vitro characterization of the sheet was investigated using microscopy investigation, quantitative analysis of alkaline phosphatase (ALP) activity, and RT-PCR. Next, we demonstrated the in vivo osteogenic potential of the engineered sheet in ectopic sites together with a porous β-tricalcium phosphate ceramic. Finally, we evaluated its efficiency in treating delayed fracture healing after wrapping the cell sheet around the mandible in a rabbit model. Results: The engineered periosteum showed sporadic mineralized nodules, elevated ALP activity, and up-regulated gene expression of osteogenic markers. After implantation in the subcutaneous pockets of the donor rabbits, the in vivo bone-forming capability of the engineered periosteum was confirmed by histological examinations. Additionally, when wrapping the engineered periosteum around a mandibular fracture gap, we observed improved bone healing and reduced amounts of fibrous tissue at the fracture site. Conclusion: The osteogenic predifferentiated BMSC sheet can act as a scaffold-free TEP to facilitate bone regeneration. Hence, our study provides a promising strategy for enhancing bone regeneration in clinical settings. To cite this article: Ma D, Yao H, Tian W, Chen F, Liu Y, Mao T, Ren L. Enhancing bone formation by transplantation of a scaffold-free tissue-engineered periosteum in a rabbit model. Clin. Oral Impl. Res. xx, 2011; 000-000. doi: 10.1111/j.1600-0501.2010.02091.x. PMID: 21303418 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Alginate microencapsulation technology for the percutaneous delivery of adipose-derived stem cells. Ann Plast Surg. 2010 Nov;65(5):497-503 Authors: Moyer HR, Kinney RC, Singh KA, Williams JK, Schwartz Z, Boyan BD Autologous fat is the ideal soft-tissue filler; however, its widespread application is limited because of variable clinical results and poor survival. Engineered fillers have the potential to maximize survival. Alginate is a hydrogel copolymer that can be engineered into spheres of <200 μm, thus facilitating mass transfer, allowing for subcutaneous injection, and protecting cells from shearing forces. PMID: 20842001 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Enhancement of matrix production and cell proliferation in human annulus cells in rotating bioreactor culture. Tissue Eng Part A. 2011 Feb 8; Authors: Yang X, Wang D, Hao J, Gong M, Arlet V, Balian G, Shen F, Li XJ Tissue engineering is a promising approach for treatment of disc degeneration. Herein, we evaluated effects of rotating bioreactor culture on the extracellular matrix production and proliferation of human annulus fibrosus (AF) cells. AF cells were embedded into alginate beads, and then cultured up to 3 weeks in a rotating wall vessel bioreactor or a static vessel. By real-time RT-PCR, expression of aggrecan, collagen type I and II, and collagen prolyl 4-hydroxylase II was remarkably elevated, while expression of matrix metalloproteinase 3 and a disintegrin and metalloproteinase with thrombospondin motifs 5 was significantly decreased under bioreactor. Biochemical analysis revealed that the levels of the whole cell-associated proteoglycan and collagen were approximately five- and two- folds in rotating bioreactor, respectively, compared to those in static culture. Moreover, AF cell proliferation was augmented in rotating bioreactor. DNA contents were three folds higher in rotating bioreactor than that in static culture. Expression of the proliferating cell nuclear antigen was robustly enhanced in rotating bioreactor as early as 1 week. Our findings suggested that rotating bioreactor culture would be an effective technique for expansion of human annulus cells for tissue engineering driven treatment of disc degeneration. PMID: 21303231 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The effect of acetylcholine-like biomimetic polymers on neuronal growth. Biomaterials. 2011 Feb 6; Authors: Tu Q, Li L, Zhang Y, Wang J, Liu R, Li M, Liu W, Wang X, Ren L, Wang J Driven by clinical needs, nerve regeneration studies have recently become the focus of research and area of growth in tissue engineering. Biomimetic polymer synthesis and functional interface construction is a promising solution to induce neuritic sprouting and guide the regenerating nerve. However, few studies have been made on primary hippocampal neurons. In this study, a new type of acetylcholine-like biomimetic polymers for their potential in biomaterial-modulated nerve regeneration application is synthesized using click chemistry and free radical polymerization. The structure of the synthesized polymers includes a "bioactive" unit (acetylcholine-like unit) and a "bioinert" unit [poly(ethylene glycol) unit]. To explore the effects of the bioactive unit and the bioinert unit on neuronal growth, different ratios of the two initial monomers poly(ethylene glycol) monomethyl ether-glycidyl methacrylate (MePEG-GMA) and dimethylaminoethyl methacrylate (DMAEMA) were employed and five different polymers were synthesized. Their chemical structures were characterized using (1)H nuclear magnetic resonance and Fourier-transform infrared spectroscopy, and their physical properties (including molecular weight, polydispersity, glass transition temperature, and melting point) were determined using gel permeation chromatography and differential scanning calorimetry. Culturing of the primary rat hippocampal neurons on the polymeric surfaces show that the ratio of the two initial monomers utilized for polymer synthesis significantly affects neuronal growth. Rat hippocampal neurons show different growth morphologies on different polymeric surfaces. The polymeric surface prepared with 1:60 (mol/mol) of MePEG-GMA to DMAEMA induces neuronal regenerative responses similar to that on poly-l-lysine, a very common benchmark material for nerve cell cultures. These results suggest that acetylcholine-like biomimetic polymers are potential biomaterials for neural engineering applications, particularly in modulating the growth of hippocampal neurons. PMID: 21303719 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Failure of Aβ(1-40) amyloid fibrils under tensile loading. Biomaterials. 2011 Feb 6; Authors: Paparcone R, Buehler MJ Amyloid fibrils and plaques are detected in the brain tissue of patients affected by Alzheimer's disease, but have also been found as part of normal physiological processes such as bacterial adhesion. Due to their highly organized structures, amyloid proteins have also been used for the development of nanomaterials, for a variety of applications including biomaterials for tissue engineering, nanolectronics, or optical devices. Past research on amyloid fibrils resulted in advances in identifying their mechanical properties, revealing a remarkable stiffness. However, the failure mechanism under tensile loading has not been elucidated yet, despite its importance for the understanding of key mechanical properties of amyloid fibrils and plaques as well as the growth and aggregation of amyloids into long fibers and plaques. Here we report a molecular level analysis of failure of amyloids under uniaxial tensile loading. Our molecular modeling results demonstrate that amyloid fibrils are extremely stiff with a Young's modulus in the range of 18-30 GPa, in good agreement with previous experimental and computational findings. The most important contribution of our study is our finding that amyloid fibrils fail at relatively small strains of 2.5%-4%, and at stress levels in the range of 1.02 to 0.64 GPa, in good agreement with experimental findings. Notably, we find that the strength properties of amyloid fibrils are extremely length dependent, and that longer amyloid fibrils show drastically smaller failure strains and failure stresses. As a result, longer fibrils in excess of hundreds of nanometers to micrometers have a greatly enhanced propensity towards spontaneous fragmentation and failure. We use a combination of simulation results and simple theoretical models to define critical fibril lengths where distinct failure mechanisms dominate. PMID: 21303720 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Adipose Derived Stromal Cells for Skeletal Regenerative Medicine. Stem Cells. 2011 Feb 8; Authors: Levi B, Longaker MT As the average age of the population grows, the incidence of osteoporosis and skeletal diseases continues to rise. Current treatment options for skeletal repair include immobilization, rigid fixation, alloplastic materials and bone grafts, all which have significant limitations, especially in the elderly. Adipose derived stromal cells (ASCs) represent a readily available abundant supply of mesenchymal stem cells which demonstrate the ability to undergo osteogenesis in vitro and in vivo, making ASCs a promising source of skeletal progenitor cells. Current protocols allow for the harvest of over 1 million cells from only 15cc of lipoaspirate. Despite the clinical use of ASCs to treat systemic inflammatory diseases, no large human clinical trials exist using ASCs for skeletal tissue engineering. The aim of this review is to define ASCs, to describe the isolation procedure of ASCs, to review the basic biology of their osteogenic differentiation, discuss cell types and scaffolds available for bone tissue engineering and lastly to explore imaging of ASCs and their potential future role in human skeletal tissue engineering efforts. PMID: 21305671 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A Promising Culture Model for Analyzing the Interaction between Adipose Tissue and Cardiomyocytes. Endocrinology. 2011 Feb 8; Authors: Anan M, Uchihashi K, Aoki S, Matsunobu A, Ootani A, Node K, Toda S The heart has epicardial adipose tissue that produces adipokines and mesenchymal stem cells. Systemic adipose tissue is involved in the pathophysiology of obesity-related heart diseases. However, the method for analyzing the direct interaction between adipose tissue and cardiomyocytes has not been established. Here we show the novel model, using collagen gel coculture of adipose tissue fragments (ATFs) and HL-1 cardiomyocytes, and electron microscopy, immunohistochemistry, real-time RT-PCR, and ELISA. HL-1 cells formed a stratified layer on ATF-nonembedded gel, whereas they formed almost a monolayer on ATF-embedded gel. ATFs promoted the apoptosis, lipid accumulation, and fatty acid transport protein (FATP) expression of FATP4 and CD36 in HL-1 cells, whereas ATFs inhibited the growth and mRNA expression of myosin, troponin T, and atrial natriuretic peptide. Treatment of leptin (100 ng/ml) and adiponectin (10 μg/ml) neither replicated nor abolished the ATF-induced morphology of HL-1 cells, whereas that of FATP4 and CD36 antibodies (25 μg/ml) never abolished it. HL-1 cells prohibited the development of CD44+/CD105+ mesenchymal stem cell-like cells and lipid-laden preadipocytes from ATFs. HL-1 cells increased the production of adiponectin in ATFs, whereas they decreased that of leptin. The data indicate that our model actively creates adipose tissue-HL-1 cardiomyocyte interaction, suggesting first that ATFs may be related to the lipotoxiciy of HL-1 cells via unknown factors plus FATP4 and CD36 and second that HL-1 cells may help to retain the static state of ATFs, affecting adipokine secretion. Our model will serve to study adipose tissue-cardiomyocyte interaction and mechanisms of obesity-related lipotoxicity and heart diseases. PMID: 21303960 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Safety of intravenous infusion of human adipose tissue-derived mesenchymal stem cells in animals and humans. Stem Cells Dev. 2011 Feb 8; Authors: Ra JC, Shin IS, Kim SH, Kang SK, Kang BC, Lee HY, Kim YJ, Jo JY, Yoon EJ, Choi HJ, Kwon E Adipose tissue-derived mesenchymal stem cells (AdMSCs) represent an attractive and ethical cell source for stem cell therapy. With the recent demonstration of MSC homing properties, intravenous applications of MSCs to cell-damaged diseases have increased. In the present study, the toxicity and tumorigenicity of human AdMSCs (hAdMSCs) were investigated for clinical application. Culture-expanded hAdMSCs showed the typical appearance, immunophenotype and differentiation capacity of MSCs, and were genetically stable at least 12 passages in culture. Cells suspended in physiological saline maintained their MSC properties in a cold storage condition for at least 3 d. To test the toxicity of hAdMSCs, different doses of hAdMSCs were injected intravenously into immunodeficient mice, and the mice were observed for 13 weeks. Even at the highest cell dose (2.5×108 cells/kg body weight), the SCID mice were viable and had no side effects. A tumorigenicity test was performed in Balb/c-nu nude mice for 26 weeks. Even at the highest cell dose (2×108 MSCs/kg), no evidence of tumor development was found. In a human clinical trial, eight male patients who had suffered a spinal cord injury more than 12 months previous were intravenously administered autologous hAdMSCs (4×108 cells) one time. None of the patients developed any serious adverse events related to hAdMSC transplantation during the 3-month follow-up. In conclusion, the systemic transplantation of hAdMSCs appears to be safe and does not induce tumor development. PMID: 21303266 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Alginate microencapsulation technology for the percutaneous delivery of adipose-derived stem cells. Ann Plast Surg. 2010 Nov;65(5):497-503 Authors: Moyer HR, Kinney RC, Singh KA, Williams JK, Schwartz Z, Boyan BD Autologous fat is the ideal soft-tissue filler; however, its widespread application is limited because of variable clinical results and poor survival. Engineered fillers have the potential to maximize survival. Alginate is a hydrogel copolymer that can be engineered into spheres of <200 μm, thus facilitating mass transfer, allowing for subcutaneous injection, and protecting cells from shearing forces. PMID: 20842001 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
No comments:
Post a Comment