|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Adipose Tissue-Derived Mesenchymal Stem Cell-Based Liver Gene Delivery. J Hepatol. 2010 Nov 3; Authors: Li H, Zhang B, Lu Y, Jorgensen M, Petersen B, Song S BACK GROUND/AIMS: Adipose tissue represents an accessible, abundant, and replenishable source of adult stem cells for potential applications in regenerative medicine. Adipose tissue-derived mesenchymal stem cells (AT-MSCs) resemble bone marrow-derived mesenchymal stem cells (BM-MSCs) with respect to morphology, immune-phenotype and multiple differentiation capability. In the present study, we investigated the feasibility of AT-MSC-based liver gene delivery for the treatment of alpha 1-antitrypsin deficiency. METHODS: Mouse AT-MSCs were tranduced by rAAV vectors and transplanted into mouse liver. RESULTS: We showed that AT-MSCs can be transduced by recombinant adeno-associated viral vector serotype 1 (rAAV1-CB-hAAT). After transplanting to mouse liver, ex vivo transduced AT-MSCs expressed the transgene product, human alpha 1-antitrypsin (hAAT). Importantly, serum levels of hAAT were sustained and no anti-hAAT antibody was detected in any recipients. CONCLUSION: These results demonstrated that AT-MSCs can be transduced by rAAV vectors, engrafted into recipient livers, contribute to liver regeneration, and serve as a platform for transgene expression without eliciting an immune response. AT-MSC-based gene therapy presents a novel approach for the treatment of liver diseases, such as AAT deficiency. PMID: 21168381 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Ascorbic acid induces in vitro proliferation of human subcutaneous adipose tissue derived mesenchymal stem cells with upregulation of embryonic stem cell pluripotency markers Oct4 and SOX 2. Hum Cell. 2010 Nov;23(4):152-5 Authors: Potdar PD, D'Souza SB Mesenchymal stem cells (MSCs) have immense therapeutic potential because of their ability to self-renew and differentiate into various connective tissue lineages. The in vitro proliferation and expansion of these cells is necessary for their use in stem cell therapy. Recently our group has developed and characterized mesenchymal stem cells from subcutaneous and visceral adipose tissue. We observed that these cells show a slower growth rate at higher passages and therefore decided to develop a supplemented medium, which will induce proliferation. Choi et al. have recently shown that the use of ascorbic acid enhances the proliferation of bone marrow derived MSCs. We therefore studied the effect of ascorbic acid on the proliferation of MSCs and characterized their phenotypes using stem cell specific molecular markers. It was observed that the use of 250 µM ascorbic acid promoted the significant growth of MSCs without loss of phenotype and differentiation potential. There was no considerable change in gene expression of cell surface markers CD105, CD13, Nanog, leukemia inhibitory factor (LIF) and Keratin 18. Moreover, the MSCs maintained in the medium supplemented with ascorbic acid for a period of 4 weeks showed increase in pluripotency markers Oct4 and SOX 2. Also cells in the experimental group retained the typical spindle shaped morphology. Thus, this study emphasizes the development of suitable growth medium for expansion of MSCs and maintenance of their undifferentiated state for further therapeutic use. PMID: 21166886 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Self-healing biomaterials. J Biomed Mater Res A. 2011 Feb;96(2):492-506 Authors: Brochu AB, Craig SL, Reichert WM The goal of this review is to introduce the biomaterials community to the emerging field of self-healing materials, and also to suggest how one could utilize and modify self-healing approaches to develop new classes of biomaterials. A brief discussion of the in vivo mechanical loading and resultant failures experienced by biomedical implants is followed by presentation of the self-healing methods for combating mechanical failure. If conventional composite materials that retard failure may be considered zeroth generation self-healing materials, then taxonomically speaking, first generation self-healing materials describe approaches that "halt" and "fill" damage, whereas second generation self-healing materials strive to "fully restore" the prefailed material structure. In spite of limited commercial use to date, primarily because the technical details have not been suitably optimized, it is likely from a practical standpoint that first generation approaches will be the first to be employed commercially, whereas second generation approaches may take longer to implement. For self-healing biomaterials the optimization of technical considerations is further compounded by the additional constraints of toxicity and biocompatibility, necessitating inclusion of separate discussions of design criteria for self-healing biomaterials. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID: 21171168 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Biomimeticity in tissue engineering scaffolds through synthetic peptide modifications-Altering chemistry for enhanced biological response. J Biomed Mater Res A. 2011 Feb;96(2):477-91 Authors: Sreejalekshmi KG, Nair PD Biomimetic and bioactive biomaterials are desirable as tissue engineering scaffolds by virtue of their capability to mimic natural environments of the extracellular matrix. Biomimeticity has been achieved by the incorporation of synthetic short peptide sequences into suitable materials either by surface modification or by bulk incorporation. Research in this area has identified several novel synthetic peptide segments, some of them with cell-specific interactions, which may serve as potential candidates for use in explicit tissue applications. This review focuses on the developments and prospective directions of incorporating short synthetic peptide sequences onto scaffolds for tissue engineering, with emphasis on the chemistry of peptide immobilization and subsequent cell responses toward modified scaffolds. The article provides a decision-tree-type flow chart indicating the most probable cellular events on a given peptide-modified scaffold along with the consolidated list of synthetic peptide sequences, supports as well as cell types used in various tissue engineering studies, and aims to serve as a quick reference guide to peptide chemists and material scientists interested in the field. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID: 21171167 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Enzyme-synthesized poly(amine-co-esters) as nonviral vectors for gene delivery. J Biomed Mater Res A. 2011 Feb;96(2):456-65 Authors: Liu J, Jiang Z, Zhou J, Zhang S, Saltzman WM A family of biodegradable poly(amine-co-esters) was synthesized in one step via enzymatic copolymerization of diesters with amino-substituted diols. Diesters of length C(4) -C(12) (i.e., from succinate to dodecanedioate) were successfully copolymerized with diethanolamines with either an alkyl (methyl, ethyl, n-butyl, t-butyl) or an aryl (phenyl) substituent on the nitrogen. Upon protonation at slightly acidic conditions, these poly(amine-co-esters) readily turned to cationic polyelectrolytes, which were capable of condensing with polyanionic DNA to form nanometer-sized polyplexes. In vitro screening with pLucDNA revealed that two of the copolymers, poly(N-methyldiethyleneamine sebacate) (PMSC) and poly(N-ethyldiethyleneamine sebacate) (PESC), possessed comparable or higher transfection efficiencies compared with Lipofectamine 2000. PMSC/pLucDNA and PESC/pLucDNA nanoparticles had desirable particle sizes (40-70 nm) for cellular uptake and were capable of functioning as proton sponges to facilitate endosomal escape after cellular uptake. These polyplex nanoparticles exhibited extremely low cytotoxicity. Furthermore, in vivo gene transfection experiments revealed that PMSC is a substantially more effective gene carrier than PEI in delivering pLucDNA to cells in tumors in mice. All these properties suggest that poly(amine-co-esters) are promising nonviral vectors for safe and efficient DNA delivery in gene therapy. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID: 21171165 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Novel tissue-derived biomimetic scaffold for regenerating the human nucleus pulposus. J Biomed Mater Res A. 2011 Feb;96(2):422-35 Authors: Mercuri JJ, Gill SS, Simionescu DT Numerous scaffold formulations have been investigated to support the regeneration of nucleus pulposus (NP) tissue for use as an early-stage therapy for intervertebral disc degeneration. Particular attention has focused on recreating the biochemical and mechanical properties of the native NP via the incorporation of exogenous extracellular matrix (ECM) components or synthetic surrogates. In the present study, we describe a novel approach to develop a tissue engineering (TE) scaffold comprised acellular porcine NP ECM. Complete decellularization of porcine NP was successfully achieved using a combination of chemical detergents, ultrasonication, and treatment with nucleases. Resulting NP scaffolds were devoid of host-cell remnants and the porcine antigen alpha-Gal. Native NP ECM components including aggrecan/chondroitin-6-sulfate and collagens types II, IX, and XI were found in physiologically relevant ratios within the NP scaffold. NP scaffold swelling capacity and unconfined mechanical properties were not significantly different from porcine NP tissue. Furthermore, NP scaffolds were conducive to repopulation with human adipose-derived stem cells as cell viability and proliferative capacity were maintained. These results demonstrate the successful decellularization of porcine NP and the resultant formation of a biomimetic scaffold exhibiting potential utility for TE the human NP. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011. PMID: 21171162 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of endothelial cells on bone regeneration using poly(L-lactide-co-1,5-dioxepan-2-one) scaffolds. J Biomed Mater Res A. 2011 Feb;96(2):349-57 Authors: Xing Z, Xue Y, Dånmark S, Schander K, Ostvold S, Arvidson K, Hellem S, Finne-Wistrand A, Albertsson AC, Mustafa K Our recent in vitro study demonstrated that endothelial cells (ECs) might influence the differentiation of bone marrow stromal cells (BMSCs). Therefore, the aim of this study was to describe this effect in vivo, using a rat calvarial bone defect model. BMSCs were isolated from femurs of two-donor Lewis rats and expanded in α-minimum essential medium containing 10% fetal bovine serum. One fifth of BMSCs were induced and differentiated into ECs in an Endothelial Cell Growth Medium-2 and then characterized by a flow cytometry. The remaining BMSCs were cultured in freshly prepared osteogenic stimulatory medium, containing dexamethasone, ascorbic acid and β-glycerophosphate. Either BMSCs alone (BMSC-group) or co-cultured ECs/BMSCs (CO-group) were seeded into poly(L-lactide-co-1,5-dioxepan-2-one) [poly(LLA-co-DXO)] scaffolds, cultured in spinner flasks, and then implanted into symmetrical calvarial defects prepared in recipient rats. The animals were sacrificed after 2 months. The formation of new bone was evaluated by radiography and histology and by the expression of osteogenic markers using reverse transcriptase-polymerized chain reaction (RT-PCR). To investigate vessel formation, histological staining was performed with EC's markers. The radiographical and histological results showed more rapid bone formation in the CO- than in the BMSC-group. However, the expression of EC's marker was similar on both groups by histological analysis after 2 months postoperatively. Furthermore, the CO-group exhibited greater expression of osteogenic markers as demonstrated by RT-PCR. The results are consistent with the previous in vitro findings that poly(LLA-co-DXO) scaffold might be suitable candidate for bone tissue engineering. In vivo, bone regeneration was enhanced by a construct of the polymer scaffold loaded with co-cultured cells. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID: 21171154 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | The dangers in adopting a tissue-engineering-centric agenda: A president's perspective. J Biomed Mater Res A. 2011 Feb;96(2):273-4 Authors: Gilbert JL PMID: 21171146 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Fabrication of chitosan/poly(ε-caprolactone) composite hydrogels for tissue engineering applications. J Mater Sci Mater Med. 2010 Dec 19; Authors: Zhong X, Ji C, Chan AK, Kazarian SG, Ruys A, Dehghani F The aim of this study was to fabricate three-dimensional (3D) porous chitosan/poly(ε-caprolactone) (PCL) hydrogels with improved mechanical properties for tissue engineering applications. A modified emulsion lyophilisation technique was developed to produce 3D chitosan/PCL hydrogels. The addition of 25 and 50 wt% of PCL into chitosan substantially enhanced the compressive strength of composite hydrogel 160 and 290%, respectively, compared to pure chitosan hydrogel. The result of ATR-FTIR imaging corroborated that PCL and chitosan were well mixed and physically co-existed in the composite structures. The composite hydrogels were constructed of homogenous structure with average pore size of 59.7 ± 14 μm and finer pores with average size of 4.4 ± 2 μm on the wall of these larger pores. The SEM and confocal laser scanning microscopy images confirmed that fibroblast cells were attached and proliferated on the 3D structure of these composite hydrogels. The composite hydrogels acquired in this study possessed homogeneous porous structure with improved mechanical strength and integrity. They may have a high potential for the production of 3D hydrogels for tissue engineering applications. PMID: 21170732 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Erratum to: In vitro studies of the ablation mechanism of periodontopathic bacteria and decontamination effect on periodontally diseased root surfaces by erbium:yttrium-aluminum-garnet laser. Lasers Med Sci. 2010 Dec 18; Authors: Akiyama F, Aoki A, Miura-Uchiyama M, Sasaki KM, Ichinose S, Umeda M, Ishikawa I, Izumi Y PMID: 21170667 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fabrication of porous polycaprolactone/hydroxyapatite (PCL/HA) blend scaffolds using a 3D plotting system for bone tissue engineering. Bioprocess Biosyst Eng. 2010 Dec 18; Authors: Park SA, Lee SH, Kim WD For tissue engineering and regeneration, a porous scaffold with interconnected networks is needed to guide cell attachment and growth/ingrowth in three-dimensional (3D) structure. Using a rapid prototyping (RP) technique, we designed and fabricated 3D plotting system and three types of scaffolds: those from polycaprolactone (PCL), those from PCL and hydroxyapatite (HA), and those from PCL/HA and with a shifted pattern structure (PCL/HA/SP scaffold). Shifted pattern structure was fabricated to increase the cell attachment/adhesion. The PCL/HA/SP scaffold had a lower compressive modulus than PCL and PCL/HA scaffold. However, it has a better cell attachment than the scaffolds without a shifted pattern. MTT assay and alkaline phosphatase activity results for the PCL/HA/SP scaffolds were significantly enhanced compared to the results for the PCL and PCL/HA scaffolds. According to their degree of cell proliferation/differentiation, the scaffolds were in the following order: PCL/HA/SP > PCL/HA > PCL. These 3D scaffolds will be applicable for tissue engineering based on unique plotting system. PMID: 21170553 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Biodegradable insulin-loaded PLGA microspheres fabricated by three different emulsification techniques:Investigation for cartilage tissue engineering. Acta Biomater. 2010 Dec 16; Authors: Andreas K, Zehbe R, Kazubek M, Grzeschik K, Sternberg N, Bäumler H, Schubert H, Sittinger M, Ringe J Growth, differentiation and migration factors facilitate the engineering of tissues but need to be administered with defined gradients over a prolonged period of time. In this study, insulin as growth factor for cartilage tissue engineering and a biodegradable PLGA delivery device were used. The aim was to comparatively investigate three different microencapsulation techniques solid-in-oil-in-water (s/o/w), water-in-oil-in-water (w/o/w) and oil-in-oil-in-water (o/o/w) for the fabrication of insulin-loaded PLGA microspheres with regard to protein loading efficiency, release and degradation kinetics, biological activity of the released protein and phagocytosis of the microspheres. Insulin-loaded PLGA microspheres of all three emulsification techniques had smooth and spherical surfaces with a negative zeta potential. The preparation technique did neither affect particle degradation nor induce phagocytosis by human leukocytes. The delivery of structurally intact and biologically active insulin from the microspheres was ensured using CD spectroscopy and MCF7 cell-based proliferation assay. However, the insulin loading efficiency (w/o/w about 80%, s/o/w 60%, o/o/w 25%) and the insulin release kinetic were influenced by the microencapsulation technique. The results demonstrate that the w/o/w microspheres are most appropriate providing high encapsulation efficiency and low initial burst release and thus were finally used for cartilage tissue engineering. Insulin released from w/o/w PLGA microspheres considerably stimulated the formation of cartilage in chondrocyte high-density pellet cultures as determined by an increased secretion of proteoglycans and collagen type II. Our results encourage further studies applying protein-loaded PLGA microspheres in combination with cell transplants or cell-free in situ tissue engineering implants to regenerate cartilage. PMID: 21168535 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | From tissue engineering to regenerative medicine in urology - The potential and the pitfalls. Adv Drug Deliv Rev. 2010 Dec 14; Authors: Feil G, Daum L, Amend B, Maurer S, Renninger M, Vaegler M, Seibold J, Stenzl A, Sievert KD Tissue engineering is a promising technique for the development of biological substitutes that can restore, maintain, or improve tissue function. The creation of human tissue-engineered products, generated of autologous somatic cells or adult stem cells with or without seeding of biocompatible matrices is a vision to resolve the lack of tissues and organs for transplantation and to offer new options for reconstructive surgery. Tissue engineering in urology aims at the reconstruction of the urinary tract by creating anatomically and functionally equal tissue. It is a rapidly evolving field in basic research and the transfer into the clinic has yet to be realized. Necessary steps from bench to bed are the proof of principle in animal models and the proof of concept in clinical trials following good manufacturing practice and ethical and legal requirements for human tissue-engineered products. Up to now, obstacles still occur in the neovascularization of implants and ingrowth of nerves in vivo. Moreover the harvesting of mesenchymal stem cells out of bone marrow as well as the explant of urothelial cells yet demands rather invasive surgery to achieve a successful outcome. Thus, other cell sources and harvesting techniques like placenta and adipose tissue for mesenchymal stem cells and bladder irrigation for urothelial cells require closer investigation. PMID: 21167237 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Value of human amniotic epithelial cells in tissue engineering for cornea. Hum Cell. 2010 Nov;23(4):141-51 Authors: Fatimah SS, Ng SL, Chua KH, Hayati AR, Tan AE, Tan GC Human amniotic epithelial cells (hAECs) are potentially one of the key players in tissue engineering due to their easy availability. The aim of the present study was to develop an optimal isolation and transportation technique, as well as to determine the immunophenotype and epithelial gene expression of hAECs. Amnion was mechanically peeled off from the chorion and digested with trypsin-ethylenediaminetetraacetic acid. The isolated hAECs were cultured in medium containing 10 ng/mL epidermal growth factor until P4. The epithelial gene expression, cell surface antigen and protein expression of hAECs were analyzed by quantitative polymerase chain reaction, flow cytometry and immunocytochemistry. hAECs were also cultured in adipogenic, osteogenic and neurogenic induction media. The best cell yield of hAECs was seen in the digestion of 15 pieces of amnion (2 × 2 cm) and isolated 30 min after digestion with trypsin. F12:Dulbecco's modified eagle medium was the best medium for short term storage at 4 °C. hAECs expressed CD9, CD44, CD73 and CD90, and negligibly expressed CD31, CD34, CD45 and CD117. After serial passage, CK3, CK19 and involucrin gene expressions were upregulated, while p63, CK1 and CK14 gene expressions were downregulated. Sustained gene expressions of integrin β1 and CK18 were observed. At initial culture, these cells might have stem-like properties. However, they differentiated after serial passage. Nonetheless, hAECs have epithelial stem cell characteristics and have the potential to differentiate into corneal epithelial cells. Further investigations are still needed to elucidate the mechanism of differentiation involved and to optimize the culture condition for long term in vitro culture. PMID: 21166885 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Elastin as a non-thrombogenic biomaterial. Tissue Eng Part B Rev. 2010 Dec 17; Authors: Waterhouse A, Wise SG, Ng MK, Weiss AS Surface-induced thrombosis is a significant issue for artificial blood-contacting materials used in the treatment of cardiovascular diseases. The development of biomaterials and tissue engineered constructs that mimic the vasculature represents a way to overcome this problem. Elastin is an extracellular matrix macromolecule that imparts arterial elasticity where it comprises up to 50% of the non-hydrated mass of the vessel. In addition to its critical role in maintaining vessel integrity and elastic properties under pulsatile flow, elastin plays an important role in signaling and regulating luminal endothelial cells and smooth muscle cells in the arterial wall. Despite its well-established significance in the vasculature and its growing use as a biomaterial in tissue engineering, the hemocompatibility of elastin is often overlooked. Past studies pointing to the potential of arterial elastin and decellularized elastin as non-thrombogenic materials have begun to be realized, with elastin scaffolds and coatings displaying increasing hemocomptibility. This review explores the mechanisms of elastin's non-thrombogenicity and highlights the current problems limiting its wider application as a biomaterial. We discuss the benefits of constructing biomaterials encompassing the relevant mechanical and biological features of elastin to provide enhanced hemocompatibility to biomaterials. PMID: 21166482 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Chemoselective Modification of Turnip Yellow Mosaic Virus by Cu(I) Catalyzed Azide-Alkyne 1,3-Dipolar Cycloaddition Reaction and Its Application in Cell Binding. Bioconjug Chem. 2010 Dec 20; Authors: Zeng Q, Saha S, Lee LA, Barnhill H, Oxsher J, Dreher T, Wang Q Turnip yellow mosaic virus (TYMV) is an icosahedral plant virus with a diameter of 28-30 nm that can be isolated in gram quantities from turnip or Chinese cabbage inexpensively. In this study, TYMV combined with spatially addressable surface chemistries was selected as a prototype bionanoparticle for modulating patterns of cell adhesion, morphology, and proliferation. We exploited the chemical reactivity of TYMV using the mild conditions of Cu(I) catalyzed azide-alkyne cycloaddition (CuAAC) reaction, the best example of "click" chemistry. Oligo-ethylene glycol (OEG) short chain, coumarintriazole, and RGD-containing peptide were grafted on the surface of TYMV via carbodiimide activation and CuAAC reaction. The bioconjugation to intact viral particles was confirmed by MS, TEM, FPLC, and SDS-PAGE with fluorescence visualization analysis. Therefore, this method is a generally useful means of incorporating various types of functionalities onto the TYMV surface. Further studies were done to learn the behavior of NIH-3T3 fibroblast cells on the modified or unmodified TYMV surfaces. OEG-modified TYMV surfaces retarded cell attachment and growth, while cell adhesion, spreading, and proliferation were dramatically enhanced on RGD-modified TYMV surfaces. Compared with RGD immobilized 3-aminopropyltriethoxysilane-coated glass surface, the cells are more ready to spread fully and proliferate on TYMV-RGD coated surface, which thus provides a more cell-friendly environment with nanometer-scale surface features. This illustrates the potential application of plant virus based materials in tissue engineering, drug delivery, and biosensing. PMID: 21166476 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Wetting effects on in vitro bioactivity and in vitro biocompatibility of laser micro-textured Ca-P coating. Biofabrication. 2010 Jun;2(2):025001 Authors: Paital SR, Cao Z, He W, Dahotre NB Calcium phosphate (Ca-P) coating on the Ti-6Al-4V alloy enhances osteoblast adhesion and tissue formation at the bone implant interface. In light of this, in the current work a laser-based coating technique was used to synthesize two different micro-textured (100 microm and 200 microm spaced line patterns) Ca-P coatings on the Ti-6Al-4V alloy and its effect on wettability and osteoblast cell adhesion were systematically studied. X-ray diffraction (XRD) analysis of the coated samples indicated the presence of precursor material, Ca10(PO4)6(OH)2 (HA) and various other additional phases such as CaTiO3, Ca3(PO4)2, TiO2 (anatase) and TiO2 (rutile) owing to the reaction between the precursor (HA) and substrate (Ti-6Al-4V) during laser processing. Confocal laser scanning microscopy-based characterization of coated samples indicated that the samples processed at 100 microm line spacing demonstrated a reduced surface roughness and smaller texture parameter value as compared to the samples processed at 200 microm spacing. The surface energy and wettability of the 100 microm spaced samples measured using a static sessile drop technique demonstrated higher surface energy and increased hydrophilicity as compared to the control (untreated Ti-6Al-4V) and the samples processed at 200 microm spacing. The tendency of coated samples for mineralization through generation of an apatite-like phase during immersion in a simulated body fluid was indicative of their in vitro bioactive nature. In light of higher surface energy and increased hydrophilicity the in vitro biocompatibility of the samples with 100 microm line spacing was demonstrated through increased cell proliferation and cell adhesion of mouse MC3T3-E1 osteoblast-like cells. PMID: 20811129 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Characterization of the flow behavior of alginate/hydroxyapatite mixtures for tissue scaffold fabrication. Biofabrication. 2009 Dec;1(4):045005 Authors: Tian XY, Li MG, Cao N, Li JW, Chen XB Mixtures of alginate and hydroxyapatite (HA) are promising materials for biomedical applications such as the fabrication of tissue scaffolds. In this paper, the flow behavior of alginate/HA mixtures was investigated and determined to be dependent on the concentration of both alginate and HA, and temperature. The relationships were mathematically established and verified with experimental results. As applied to the tissue scaffold fabrication, the flow rate of the biomaterial solution was predicted from the established flow behavior and verified by experiments. On this basis, the moving speed of the needle was determined and used in the tissue scaffold fabrication. The results obtained show that the knowledge of the flow behavior is essential to the fabrication of tissue scaffolds with an interconnected microstructure. PMID: 20811114 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | A Lindenmayer system-based approach for the design of nutrient delivery networks in tissue constructs. Biofabrication. 2009 Dec;1(4):045004 Authors: Yasar O, Lan SF, Starly B Large thick tissue constructs have reported limited success primarily due to the inability of cells to survive deep within the scaffold. Without access to adequate nutrients, cells placed deep within the tissue construct will die out, leading to non-uniform tissue regeneration. Currently, there is a necessity to design nutrient conduit networks within the tissue construct to enable cells to survive in the matrix. However, the design of complex networks within a tissue construct is challenging. In this paper, we present the Lindenmayer system, an elegant fractal-based language algorithm framework, to generate conduit networks in two- and three-dimensional architecture with several degrees of complexity. The conduit network maintains a parent-child relationship between each branch of the network. Several L-system parameters have been studied-branching angle, branch length, ratio of parent to child branch diameter, etc-to simulate several architectures under a given L-system notation. We have also presented a layered manufacturing-based UV-photopolymerization process using the Texas Instruments DLP system to fabricate the branched structures. This preliminary work showcases the applicability of L-system-based construct designs to drive scaffold fabrication systems. PMID: 20811113 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Coating of hydrophobins on three-dimensional electrospun poly(lactic-co-glycolic acid) scaffolds for cell adhesion. Biofabrication. 2009 Sep;1(3):035004 Authors: Hou S, Li X, Li X, Feng X Surface modification with hydrophobins is very important for cell adhesion in its applications in biosensor fabrication. In this study, we modified the surface of three-dimensional electrospun poly(lactide-co-glycolide) (PLGA) scaffolds with hydrophobin HFBI and collagen, and investigated its applications for cell adhesion. We found that HFBI could not only improve the hydrophilicity of the three-dimensional electrospun PLGA scaffolds but also endow the electrospun PLGA scaffolds with water permeability. This permeability should be attributed to both the hydrophilicity of the modified PLGA surface and the large positive capillary effect induced by the microstructures. Further experiment indicated that HFBI modification could improve collagen immobilization on the electrospun PLGA scaffolds and the HFBI/collagen modified electrospun PLGA scaffolds showed higher efficiency in promoting cell adhesion than the native PLGA scaffolds. This finding should be of potential application in biosensor device fabrication. PMID: 20811108 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Computer-aided design of microvasculature systems for use in vascular scaffold production. Biofabrication. 2009 Sep;1(3):035002 Authors: Mondy WL, Cameron D, Timmermans JP, De Clerck N, Sasov A, Casteleyn C, Piegl LA In vitro biomedical engineering of intact, functional vascular networks, which include capillary structures, is a prerequisite for adequate vascular scaffold production. Capillary structures are necessary since they provide the elements and compounds for the growth, function and maintenance of 3D tissue structures. Computer-aided modeling of stereolithographic (STL) micro-computer tomographic (micro-CT) 3D models is a technique that enables us to mimic the design of vascular tree systems containing capillary beds, found in tissues. In our first paper (Mondy et al 2009 Tissue Eng. at press), using micro-CT, we studied the possibility of using vascular tissues to produce data capable of aiding the design of vascular tree scaffolding, which would help in the reverse engineering of a complete vascular tree system including capillary bed structures. In this paper, we used STL models of large datasets of computer-aided design (CAD) data of vascular structures which contained capillary structures that mimic those in the dermal layers of rabbit skin. Using CAD software we created from 3D STL models a bio-CAD design for the development of capillary-containing vascular tree scaffolding for skin. This method is designed to enhance a variety of therapeutic protocols including, but not limited to, organ and tissue repair, systemic disease mediation and cell/tissue transplantation therapy. Our successful approach to in vitro vasculogenesis will allow the bioengineering of various other types of 3D tissue structures, and as such greatly expands the potential applications of biomedical engineering technology into the fields of biomedical research and medicine. PMID: 20811106 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Fabrication and characterization of bio-engineered cardiac pseudo tissues. Biofabrication. 2009 Sep;1(3):035001 Authors: Xu T, Baicu C, Aho M, Zile M, Boland T We report on fabricating functional three-dimensional (3D) tissue constructs using an inkjet based bio-prototyping method. With the use of modified inkjet printers, contractile cardiac hybrids that exhibit the forms of the 3D rectangular sheet and even the 'half heart' (with two connected ventricles) have been fabricated by arranging alternate layers of biocompatible alginate hydrogels and mammalian cardiac cells according to pre-designed 3D patterns. In this study, primary feline adult and H1 cardiomyocytes were used as model cardiac cells. Alginate hydrogels with controlled micro-shell structures were built by spraying cross-linkers in micro-drops onto un-gelled alginic acid. The cells remained viable in constructs as thick as 1 cm due to the programmed porosity. Microscopic and macroscopic contractile functions of these cardiomyocyte constructs were observed in vitro. These results suggest that the inkjet bio-prototyping method could be used for hierarchical design of functional cardiac pseudo tissues, balanced with porosity for mass transport and structural support. PMID: 20811105 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | In vivo performance of a phospholipid-coated bioerodable elastomeric graft for small-diameter vascular applications. J Biomed Mater Res A. 2011 Feb;96(2):436-48 Authors: Soletti L, Nieponice A, Hong Y, Ye SH, Stankus JJ, Wagner WR, Vorp DA There remains a great need for vascular substitutes for small-diameter applications. The use of an elastomeric biodegradable material, enabling acute antithrombogenicity and long-term in vivo remodeling, could be beneficial for this purpose. Conduits (1.3 mm internal diameter) were obtained by electrospinning biodegradable poly(ester urethane)urea (PEUU), and by luminally immobilizing a non-thrombogenic, 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymer. Platelet adhesion was characterized in vitro after contact with ovine blood. The conduits were implanted as aortic interposition grafts in the rat for 4, 8, 12, and 24 weeks. Surface treatment resulted in a 10-fold decrease in platelet adhesion compared to untreated material. Patency at 8 weeks was 92% for the coated grafts compared to 40% for the non-coated grafts. Histology at 8 and 12 weeks demonstrated formation of cellularized neotissue consisting of aligned collagen and elastin. The lumen of the grafts was confluent with cells qualitatively aligned in the direction of blood flow. Immunohistochemistry suggested the presence of smooth muscle cells in the medial layer of the neotissue and endothelial cells lining the lumen. Mechanically, the grafts were less compliant than rat aortas prior to implantation (4.5 ± 2.0 × 10(-4) mmHg(-1) vs. 14.2 ± 1.1 × 10(-4) mmHg(-1) , respectively), then after 4 weeks in vivo they approximated native values, but subsequently became stiffer again at later time points. The novel coated grafts exhibited promising antithrombogenic and mechanical properties for small-diameter arterial revascularization. Further evaluation in vivo will be required to demonstrate complete remodeling of the graft into a native-like artery. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID: 21171163 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Current developments in the use of stem cell for therapeutic neovascularisation: is the future therapy "cell-free"? Swiss Med Wkly. 2010;140:w13130 Authors: Yang Z, Di Santo S, Kalka C The plasticity and self-regenerative properties of stem cells have opened new avenues in regenerative medicine. Greater understanding of the biology of stem cells is followed by growing expectations of a rapid translation into alternative therapeutic options. Recent preclinical studies and clinical trials employing stem and progenitor cells from different sources have shown encouraging results. However, their underlying mechanisms are still poorly understood, the potential adverse effects and the discrepancy in efficacy remain to be further investigated. Their essential role in vessel regeneration has made endothelial progenitor cells (EPC) a suitable candidate for therapeutic applications aiming at tissue revascularisation. Recent evidence suggests that EPC contribute to neovascularisation not only by direct participation in tissue homeostasis but mainly via paracrine mechanisms. In future, novel therapeutic strategies could be based on EPC paracrine factors or synthetic factors, and replace cell transplantation. PMID: 21170763 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | High-efficient generation of induced pluripotent stem cells from human astrocytes. PLoS One. 2010;5(12):e15526 Authors: Ruiz S, Brennand K, Panopoulos AD, Herrerías A, Gage FH, Izpisua-Belmonte JC The reprogramming of human somatic cells to induced pluripotent stem (hiPS) cells enables the possibility of generating patient-specific autologous cells for regenerative medicine. A number of human somatic cell types have been reported to generate hiPS cells, including fibroblasts, keratinocytes and peripheral blood cells, with variable reprogramming efficiencies and kinetics. Here, we show that human astrocytes can also be reprogrammed into hiPS (ASThiPS) cells, with similar efficiencies to keratinocytes, which are currently reported to have one of the highest somatic reprogramming efficiencies. ASThiPS lines were indistinguishable from human embryonic stem (ES) cells based on the expression of pluripotent markers and the ability to differentiate into the three embryonic germ layers in vitro by embryoid body generation and in vivo by teratoma formation after injection into immunodeficient mice. Our data demonstrates that a human differentiated neural cell type can be reprogrammed to pluripotency and is consistent with the universality of the somatic reprogramming procedure. PMID: 21170306 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Introducing Hand-Assisted Retroperitoneoscopic Live Donor Nephrectomy: Learning Curves and Development Based on 413 Consecutive Cases in Four Centers. Transplantation. 2010 Dec 16; Authors: Wadström J, Biglarnia A, Gjertsen H, Sugitani A, Fronek J BACKGROUND.: Hand-assisted and retroperitoneoscopic techniques reduce the risk of bleeding and intraabdominal complications in living donor nephrectomy (LDN). This study reports on our four-center experience, development, and learning curves from the first 413 LDNs using a hand-assisted retroperitoneoscopic (HARS) technique. METHODS.: The first 413 consecutive donors operated on using HARS were included in the study. Donor demographics, perioperative and postoperative data, complications, and recipient outcomes have been compiled. The data were analyzed as a whole and separately for each center, looking at center differences and learning curves over time. RESULTS.: Significant differences were found in donor demographics between centers for the variables: age, body mass index, number of arteries, and side of operation. Mean operating time was 170.2 min, with significant differences between centers. Operating time was also significantly influenced by learning curves, sex/body mass index, and side of operation. Warm ischemia time differed significantly between centers and was influenced by center-wise learning and number of arteries. Overall conversion rate was 2.4% and differed significantly between centers. There was no mortality and no intraabdominal complications. Apart from the conversions and one pulmonary embolism, there were no major intraoperative or postoperative complications. Overall 3-month graft survival was 99%, with 96% immediate onset of function and 1% ureteral complications. CONCLUSIONS.: The HARS technique reduces the risk of intraabdominal complications. It can be implemented with excellent donor and recipient outcomes despite different population demographics and center/surgeon-related tradition and experience. On the basis of our experience, we recommend the technique to increase the safety margin of LDN. PMID: 21169880 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | IL-2-Controlled Expression of Multiple T Cell Trafficking Genes and Th2 Cytokines in the Regulatory T Cell-Deficient Scurfy Mice: Implication to Multiorgan Inflammation and Control of Skin and Lung Inflammation. J Immunol. 2010 Dec 17; Authors: Sharma R, Sharma PR, Kim YC, Leitinger N, Lee JK, Fu SM, Ju ST Scurfy (Sf) mice bear a mutation in the Foxp3 transcription factor, lack regulatory T cells (Treg), develop multiorgan inflammation, and die prematurely. The major target organs affected are skin, lungs, and liver. Sf mice lacking the Il2 gene (Sf.Il2(-/-)), despite being devoid of Treg, did not develop skin and lung inflammation, but the inflammation in liver, pancreas, submandibular gland, and colon remained. Genome-wide microarray analysis revealed hundreds of genes that were differentially regulated among Sf, Sf.Il2(-/-), and B6 CD4(+) T cells, but the most significant changes were those encoding receptors for trafficking/chemotaxis/retention and cytokines. Our study suggests that IL-2 controls the skin and lung inflammation in Sf mice in an apparent "organ-specific" manner through two novel mechanisms: by regulating the expression of genes encoding a variety of receptors for T cell trafficking/chemotaxis/retention and by regulating Th2 cell expansion and cytokine production. Thus, IL-2 is potentially a master regulator for multiorgan inflammation and an underlying etiological factor for various diseases associated with skin and lung inflammation. PMID: 21169543 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Antimuscarinic Mechanisms and the Overactive Detrusor: An Update. Eur Urol. 2010 Dec 8; Authors: Andersson KE CONTEXT: Antimuscarinics are the drugs of choice for the treatment of detrusor overactivity (DO) and overactive bladder (OAB) syndrome. However, the mechanisms for their beneficial effects have not yet been definitely established. OBJECTIVE: Literature available on the pathophysiologic aspects of storage symptoms and of antimuscarinic actions on the bladder was reviewed. EVIDENCE ACQUISITION: Medline was searched for the period ending October 2010 and included studies on human and animal tissues and animal models. Clinical studies exploring mechanisms involved in the effects of antimuscarinics were included. Searches were limited to the English language. EVIDENCE SYNTHESIS: Evidence for release of acetylcholine (ACh) from non-neuronal as well as neuronal sources during bladder filling has been demonstrated in isolated animal bladders as well as the human bladder. Urothelially derived ACh, probably via release of adenosine triphosphate, may stimulate afferent activity ("afferent noise") from the bladder contributing to OAB and DO. Afferent noise may also be generated by local ACh release within the detrusor muscle. This afferent activity can be inhibited by antimuscarinics at the low concentrations obtained with doses recommended for clinical use in OAB/DO. Within this therapeutic window, antimuscarinics may decrease OAB symptoms and DO without affecting the voiding contraction. Changes in muscarinic receptor functions have been demonstrated with aging and in different disorders associated with OAB/DO. CONCLUSIONS: ACh, derived from non-neuronal as well as neuronal sources and during bladder filling, directly or indirectly stimulates afferent activity from the bladder, contributing to OAB and DO. By inhibiting this effect, antimuscarinics may decrease OAB symptoms and DO without affecting the voiding contraction. Even if changes in muscarinic receptor functions may occur with aging and in different disorders associated with OAB/DO, such changes have not been shown convincingly to modify the beneficial effect of antimuscarinics in OAB/DO. PMID: 21168951 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Cannabinor, a Selective Cannabinoid-2 Receptor Agonist, Improves Bladder Emptying in Rats With Partial Urethral Obstruction. J Urol. 2010 Dec 18; Authors: Gratzke C, Streng T, Stief CG, Alroy I, Limberg BJ, Downs TR, Rosenbaum JS, Hedlund P, Andersson KE PURPOSE:: We studied the effects of chronic treatment with the novel selective cannabinoid 2 receptor agonist cannabinor (Procter&Gamble Pharmaceuticals, Cincinnatti, Ohio) on bladder function in conscious rats with partial urethral obstruction and on the functional properties of isolated detrusor muscle. MATERIALS AND METHODS:: A total of 24 female Sprague-Dawley® rats with surgically created partial urethral obstruction received daily intraperitoneal injections of 3 mg/kg cannabinor (12) or saline as controls (12) for 2 weeks. Cystometry was done, the rats were sacrificed and the bladders were prepared for in vitro studies. RESULTS:: Mean ± SEM bladder weight was 0.97 ± 0.15 gm in controls and 0.53 ± 0.08 gm in cannabinor treated rats (p <0.05). There was no difference between the groups in the mean micturition interval, or mean baseline, threshold, flow or maximum pressure. In controls and cannabinor treated rats mean post-void residual volume was 0.28 ± 0.07 and 0.06 ± 0.02 ml, mean micturition compliance was 0.032 ± 0.006 and 0.069 ± 0.016 ml/cm H(2)O, and mean bladder wall force at the start of flow was 950 ± 280 and 1,647 ± 325 mN/gm, respectively (each p <0.05). Nonvoiding contractions were significantly less frequent in cannabinor treated rats than in controls. We noted no difference in carbachol (Sigma®) half maximum concentration between the groups but the carbachol maximum response in detrusor strips from cannabinor treated rats was significantly higher than that in control strips. CONCLUSIONS:: In rats with partial urethral obstruction treated daily for 14 days with cannabinor bladder weight was lower, the ability to empty the bladder was preserved and nonvoiding contraction frequency was low compared to those in controls. Detrusor preparations from cannabinor treated rats showed a higher response to nerve stimulation than those from controls. Selective cannabinoid 2 receptor activation may be a novel principle to enable improved bladder function after partial urethral obstruction. PMID: 21168864 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Adipose Tissue-Derived Mesenchymal Stem Cell-Based Liver Gene Delivery. J Hepatol. 2010 Nov 3; Authors: Li H, Zhang B, Lu Y, Jorgensen M, Petersen B, Song S BACK GROUND/AIMS: Adipose tissue represents an accessible, abundant, and replenishable source of adult stem cells for potential applications in regenerative medicine. Adipose tissue-derived mesenchymal stem cells (AT-MSCs) resemble bone marrow-derived mesenchymal stem cells (BM-MSCs) with respect to morphology, immune-phenotype and multiple differentiation capability. In the present study, we investigated the feasibility of AT-MSC-based liver gene delivery for the treatment of alpha 1-antitrypsin deficiency. METHODS: Mouse AT-MSCs were tranduced by rAAV vectors and transplanted into mouse liver. RESULTS: We showed that AT-MSCs can be transduced by recombinant adeno-associated viral vector serotype 1 (rAAV1-CB-hAAT). After transplanting to mouse liver, ex vivo transduced AT-MSCs expressed the transgene product, human alpha 1-antitrypsin (hAAT). Importantly, serum levels of hAAT were sustained and no anti-hAAT antibody was detected in any recipients. CONCLUSION: These results demonstrated that AT-MSCs can be transduced by rAAV vectors, engrafted into recipient livers, contribute to liver regeneration, and serve as a platform for transgene expression without eliciting an immune response. AT-MSC-based gene therapy presents a novel approach for the treatment of liver diseases, such as AAT deficiency. PMID: 21168381 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | γ-Secretase Inhibitor-I Enhances Radiosensitivity of Glioblastoma Cell Lines by Depleting CD133(+) Tumor Cells. Arch Med Res. 2010 Oct;41(7):519-29 Authors: Lin J, Zhang XM, Yang JC, Ye YB, Luo SQ Glioblastoma is a deadly primary brain tumor with great resistance to radiotherapy. To reverse its radioresistance is important for improving prognosis. Gamma-secretase inhibitors (GSI) have been proven to have anti-tumor effects, yet the knowledge of their influences on glioblastomas is still limited. PMID: 21167391 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Acetylation and Nuclear Receptor Action. J Steroid Biochem Mol Biol. 2010 Dec 14; Authors: Wang C, Tian L, Popov VM, Pestell RG Acetylation is an essential post-translational modification featuring an acetyl group that is covalently conjugated to a protein substrate. Histone acetylation was first proposed nearly half a century ago by Dr. Vincent Allfrey. Subsequent studies have shown that the acetylated core histones are often associated with transcriptionally active chromatin. Acetylation at lysine residues of histone tails neutralizes the positive charge, which decreases their binding ability to DNA and increases the accessibility of transcription factors and coactivators to the chromatin template. In addition to histones, a number of non-histone substrates are acetylated. Acetylation of non-histone proteins governs biological processes, such as cellular proliferation and survival, transcriptional activity, and intracellular trafficking. We demonstrated that acetylation of transcription factors can regulate cellular growth. Furthermore, we showed that nuclear receptors (NRs) are acetylated at a phylogenetically conserved motif. Since our initial observations with the estrogen and androgen receptors, more than a dozen NRs have been shown to function as substrates for acetyltransferases with diverse functional consequences. This review focuses on the acetylation of NRs and the effect of acetylation on NR function. We discuss the potential role of acetylation in disease initiation and progression with an emphasis on tumorigenesis. PMID: 21167281 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | From tissue engineering to regenerative medicine in urology - The potential and the pitfalls. Adv Drug Deliv Rev. 2010 Dec 14; Authors: Feil G, Daum L, Amend B, Maurer S, Renninger M, Vaegler M, Seibold J, Stenzl A, Sievert KD Tissue engineering is a promising technique for the development of biological substitutes that can restore, maintain, or improve tissue function. The creation of human tissue-engineered products, generated of autologous somatic cells or adult stem cells with or without seeding of biocompatible matrices is a vision to resolve the lack of tissues and organs for transplantation and to offer new options for reconstructive surgery. Tissue engineering in urology aims at the reconstruction of the urinary tract by creating anatomically and functionally equal tissue. It is a rapidly evolving field in basic research and the transfer into the clinic has yet to be realized. Necessary steps from bench to bed are the proof of principle in animal models and the proof of concept in clinical trials following good manufacturing practice and ethical and legal requirements for human tissue-engineered products. Up to now, obstacles still occur in the neovascularization of implants and ingrowth of nerves in vivo. Moreover the harvesting of mesenchymal stem cells out of bone marrow as well as the explant of urothelial cells yet demands rather invasive surgery to achieve a successful outcome. Thus, other cell sources and harvesting techniques like placenta and adipose tissue for mesenchymal stem cells and bladder irrigation for urothelial cells require closer investigation. PMID: 21167237 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | In vitro and in vivo properties of distinct populations of amniotic fluid mesenchymal progenitor cells. J Cell Mol Med. 2010 Sep 27; Authors: Roubelakis MG, Bitsika V, Zagoura D, Trohatou O, Pappa KI, Makridakis M, Antsaklis A, Vlahou A, Anagnou NP Human mesenchymal progenitor cells (MPCs) are considered to be of great promise for use in tissue repair and regenerative medicine. MPCs represent multipotent adherent cells, able to give rise to multiple mesenchymal lineages such as osteoblasts, adipocytes or chondrocytes. Recently, we identified and characterized human second trimester amniotic fluid (AF) as a novel source of MPCs. Herein, we found that early colonies of AF-MPCs consisted of two morphologically distinct adherent cell types, termed as spindle-shaped (SS) and round-shaped (RS). A detailed analysis of these two populations showed that SS-AF-MPCs expressed CD90 antigen in a higher level and exhibited a greater proliferation and differentiation potential. To characterize better the molecular identity of these two populations, we have generated a comparative proteomic map of SS-AF-MPCs and RS-AF-MPCs, identifying 25 differentially expressed proteins and 10 proteins uniquely expressed in RS-AF-MPCs. Furthermore, SS-AF-MPCs exhibited significantly higher migration ability on extracellular matrices, such as fibronectin and laminin in vitro, compared to RS-AF-MPCs and thus we further evaluated SS-AF-MPCs for potential use as therapeutic tools in vivo. Therefore, we tested whether GFP-lentiviral transduced SS-AF-MPCs retained their stem cell identity, proliferation and differentiation potential. GFP-SS-AF-MPCs were then successfully delivered into immunosuppressed mice, distributed in different tissues and survived longterm in vivo. In summary, these results demonstrated that AF-MPCs consisted of at least two different MPC populations. Additionally, SS-AF-MPCs, isolated based on their colony morphology and CD90 expression, represented the only MPC population that can be expanded easily in culture and used as an efficient tool for future in vivo therapeutic applications. PMID: 21166769 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Optimization of culture conditions for the expansion of umbilical cord derived MSC like cells using xeno-free culture conditions. Tissue Eng Part C Methods. 2010 Dec 17; Authors: Hatlapatka T, Moretti P, Lavrentieva A, Hass R, Marquardt N, Roland J, Kasper C First isolated from bone marrow, mesenchymal stem or stromal cells (MSC) were shown to be present in several post-natal and extraembryonic tissues as well as in a large variety of fetal tissues (e.g. fatty tissue, dental pulp, placenta, umbilical cord blood and tissue). In this study, an optimized protocol for the expansion of MSC-like cells from whole umbilical cord tissue under xeno-free culture conditions is proposed. Different fetal calf sera (FCS) and human serum (HS) were compared with regard to cell proliferation and MSC marker stability in long-term expansion experiments and HS was shown to support optimal growth conditions. Additionally, the optimal concentration of HS during the cultivation was determined. With regard to cell proliferative potential, apoptosis, colony-forming unit fibroblast (CFU-F) frequency and cell senescence, our findings suggest that an efficient expansion of the cells is carried out best in media supplemented with 10% HS. Under our given xeno-free culture conditions, MSC-like cells were found to display in vitro immunoprivileged and immunomodulatory properties, which were assessed by co-culture and transwell culture experiments with carboxyfluorescein diacetate succinimidyl ester labeled (CFSE) peripheral blood mononuclear cells (PBMC). These findings may be of great value for the establishment of biotechnological protocols for the delivery of sufficient cell numbers of high quality for regenerative medicine purposes. PMID: 21166520 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Origin matters: differences in embryonic tissue origin and Wnt signaling determine the osteogenic potential and healing capacity of frontal and parietal calvarial bones. J Bone Miner Res. 2010 Jul;25(7):1680-94 Authors: Quarto N, Wan DC, Kwan MD, Panetta NJ, Li S, Longaker MT Calvarial bones arise from two embryonic tissues, namely, the neural crest and the mesoderm. In this study we have addressed the important question of whether disparate embryonic tissue origins impart variable osteogenic potential and regenerative capacity to calvarial bones, as well as what the underlying molecular mechanism(s). Thus, by performing in vitro and in vivo studies, we have investigated whether differences exist between neural crest-derived frontal and paraxial mesodermal-derived parietal bone. Of interest, our data indicate that calvarial bone osteoblasts of neural crest origin have superior potential for osteogenic differentiation. Furthermore, neural crest-derived frontal bone displays a superior capacity to undergo osseous healing compared with calvarial bone of paraxial mesoderm origin. Our study identified both in vitro and in vivo enhanced endogenous canonical Wnt signaling in frontal bone compared with parietal bone. In addition, we demonstrate that constitutive activation of canonical Wnt signaling in paraxial mesodermal-derived parietal osteoblasts mimics the osteogenic potential of frontal osteoblasts, whereas knockdown of canonical Wnt signaling dramatically impairs the greater osteogenic potential of neural crest-derived frontal osteoblasts. Moreover, fibroblast growth factor 2 (FGF-2) treatment induces phosphorylation of GSK-3beta and increases the nuclear levels of beta-catenin in osteoblasts, suggesting that enhanced activation of Wnt signaling might be mediated by FGF. Taken together, our data provide compelling evidence that indeed embryonic tissue origin makes a difference and that active canonical Wnt signaling plays a major role in contributing to the superior intrinsic osteogenic potential and tissue regeneration observed in neural crest-derived frontal bone. PMID: 19929441 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Ascorbic acid induces in vitro proliferation of human subcutaneous adipose tissue derived mesenchymal stem cells with upregulation of embryonic stem cell pluripotency markers Oct4 and SOX 2. Hum Cell. 2010 Nov;23(4):152-5 Authors: Potdar PD, D'Souza SB Mesenchymal stem cells (MSCs) have immense therapeutic potential because of their ability to self-renew and differentiate into various connective tissue lineages. The in vitro proliferation and expansion of these cells is necessary for their use in stem cell therapy. Recently our group has developed and characterized mesenchymal stem cells from subcutaneous and visceral adipose tissue. We observed that these cells show a slower growth rate at higher passages and therefore decided to develop a supplemented medium, which will induce proliferation. Choi et al. have recently shown that the use of ascorbic acid enhances the proliferation of bone marrow derived MSCs. We therefore studied the effect of ascorbic acid on the proliferation of MSCs and characterized their phenotypes using stem cell specific molecular markers. It was observed that the use of 250 µM ascorbic acid promoted the significant growth of MSCs without loss of phenotype and differentiation potential. There was no considerable change in gene expression of cell surface markers CD105, CD13, Nanog, leukemia inhibitory factor (LIF) and Keratin 18. Moreover, the MSCs maintained in the medium supplemented with ascorbic acid for a period of 4 weeks showed increase in pluripotency markers Oct4 and SOX 2. Also cells in the experimental group retained the typical spindle shaped morphology. Thus, this study emphasizes the development of suitable growth medium for expansion of MSCs and maintenance of their undifferentiated state for further therapeutic use. PMID: 21166886 [PubMed - in process] | | | | | | | | | |  | |  | |  |
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