|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | A new paradigm for the understanding of obesity: the role of stem cells. Arch Physiol Biochem. 2011 May 6; Authors: San Martín N, Gálvez BG Obesity is a pandemic disorder that can be defined as a chronic excess of adipose tissue that increases the risk of suffering chronic diseases such as, diabetes, arterial hypertension, stroke and some forms of cancer. We now know that adipose tissue, aside from being an energy store, is also an important endocrine and metabolic organ. Recently, new mechanisms that control obesity have been identified, such as the equilibrium between white and brown adipose tissue, the localization of adipose mass (visceral or ventral), and the presence of adipose and mesenchymal stem cells. In this review, we describe the implication of these stem cell types in the normal physiology and dysfunction of adipose tissue. These stem cells provide a potential target for modulating the response of the body to obesity and diabetes, as well as a potential tool for regenerative medicine. PMID: 21545335 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Activation of the ERK1/2 Mitogen-Activated Protein Kinase Cascade by Dentin Matrix Protein 1 Promotes Osteoblast Differentiation. Cells Tissues Organs. 2011 May 6; Authors: Eapen A, Ramachandran A, Pratap J, George A DMP1 has been shown to play many roles in osteogenesis. We recently demonstrated that calcium-mediated stress kinase activation by DMP1 leads to osteoblast differentiation. In this study we demonstrate that DMP1 can also activate the extracellular signal-regulated kinase (ERK)-MAPK pathway. This activation was mediated through the RGD integrin-binding domain in DMP1. Further, we demonstrate that Runx2, an essential transcription factor, is stimulated by the ERK-MAPK pathway. PMID: 21546758 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fetomaternal microchimerism: Some answers and many new questions. Chimerism. 2011 1;2(1):16-18 Authors: Tan KH, Zeng XX, Sasajala P, Yeo A, Udolph G The transfer of fetal cells into mothers during pregnancy and their organ specific integration is a well recognized phenomenon in placental vertebrates. Recently, it has been reported that some fetal cells found in the mothers have progenitor cell-like features such as multilineage differentiation potential and as a consequence they were termed pregnancy associated progenitor cells (PAPC). The multilineage differentiation potential suggested some level of cellular plasticity, which these cells share with other stem or progenitor cells. In this context, we have shown that PAPCs indeed express neural stem cell and markers for developing neurons in the brain and that PAPCs morphologically mature into neurons over time. The stem/progenitor properties of PAPCs raises the hope that they might be valuable for studying the functional integration of foreign cells into preexisting tissues and organs, for example in cellular therapies. The functional integration of transplanted cells and their connectivity to the host circuitry is still a major bottleneck in cellular therapies particularly for the brain. The animal models of fetomaternal microchimerism might provide valuable insights into the mechanism how cells survive, migrate, integrate and differentiate in a foreign environment of a host. This review discusses some of the recent findings in the field of fetomaternal microchimerism. It also tries to identify some major gaps of knowledge and raises some questions resulting from the recent advances. Studying fetomaternal microchimerism and the properties of PAPCs in greater detail might pave the way to advance cell based regenerative medicine as well as transplantation medicine. PMID: 21547031 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Cancer stem cells in gliomas: Identifying and understanding the apex cell in cancer's hierarchy. Glia. 2011 May 5; Authors: Venere M, Fine HA, Dirks PB, Rich JN Neuro-oncology research has rediscovered a complexity of nervous system cancers through the incorporation of cellular heterogeneity into tumor models with cellular subsets displaying stem-cell characteristics. Self-renewing cancer stem cells (CSCs) can propagate tumors and yield nontumorigenic tumor bulk cells that display a more differentiated phenotype. The ability to prospectively isolate and interrogate CSCs is defining molecular mechanisms responsible for the tumor maintenance and growth. The clinical relevance of CSCs has been supported by their resistance to cytotoxic therapies and their promotion of tumor angiogenesis. Although the field of CSC biology is relatively young, continued elucidation of the features of these cells holds promise for the development of novel patient therapies. © 2011 Wiley-Liss, Inc. PMID: 21547954 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | CaSiO(3) microstructure modulating the in vitro and in vivo bioactivity of poly(lactide-co-glycolide) microspheres. J Biomed Mater Res A. 2011 May 4; Authors: Wu C, Zhang Y, Fan W, Ke X, Hu X, Zhou Y, Xiao Y Poly(lactide-co-glycolide) (PLGA) microspheres have been used for regenerative medicine due to their ability for drug delivery and generally good biocompatibility, but they lack adequate bioactivity for bone repair application. CaSiO(3) (CS) has been proposed as a new class of material suitable for bone tissue repair due to its excellent bioactivity. In this study, we set out to incorporate CS into PLGA microspheres to investigate how the phase structure (amorphous and crystal) of CS influences the in vitro and in vivo bioactivity of the composite microspheres, with a view to the application for bone regeneration. X-ray diffraction (XRD), N(2) adsorption-desorption analysis, and scanning electron microscopy (SEM) were used to analyze the phase structure, surface area/pore volume, and microstructure of amorphous CS (aCS) and crystal CS (cCS), as well as their composite microspheres. The in vitro bioactivity of aCS and cCS-PLGA microspheres was evaluated by investigating their apatite-mineralization ability in simulated body fluids (SBF) and the viability of human bone mesenchymal stem cells (BMSCs). The in vivo bioactivity was investigated by measuring their de novo bone-formation ability. The results showed that the incorporation of both aCS and cCS enhanced the in vitro and in vivo bioactivity of PLGA microspheres. cCS/PLGA microspheres improved better in vitro BMSC viability and de novo bone-formation ability in vivo, compared to aCS/PLGA microspheres. Our study indicates that controlling the phase structure of CS is a promising method to modulate the bioactivity of polymer microsphere system for potential bone tissue regeneration. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID: 21548064 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Genetic manipulations in the rat: progress and prospects. Curr Opin Nephrol Hypertens. 2011 May 5; Authors: Huang G, Ashton C, Kumbhani DS, Ying QL PURPOSE OF REVIEW: Several advances have been made to manipulate the rat genome in the last 2 years. This review aims to describe these advances in rat genetic manipulations, with an emphasis on their current status and their prospects and applications in the postgenomic era. RECENT FINDINGS: Authentic rat embryonic stem cells were derived in 2008 using the 2i/3i culture system. This led to the generation of the first gene knockout rats via embryonic stem cell-based gene targeting. The development of zinc-finger nucleases (ZFNs) provided an alternative approach that avoids the necessity of germline competent embryonic stem cells. Meanwhile, improvements have been made to the well established random mutagenesis mediated by transposons or N-ethyl-N-nitrosourea (ENU). The in-vitro rat spermatogonial stem cell (SSC) system has greatly optimized these phenotype-driven approaches for future applications. SUMMARY: The rat has long been a prime model organism in physiological, pharmacological and neurobehavioral studies. The recent advances of rat reverse genetic approaches, together with the classical ENU and transposon mutagenesis system, will contribute tremendously to the deciphering of gene functions and the creation of rat disease models. PMID: 21546835 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A new paradigm for the understanding of obesity: the role of stem cells. Arch Physiol Biochem. 2011 May 6; Authors: San Martín N, Gálvez BG Obesity is a pandemic disorder that can be defined as a chronic excess of adipose tissue that increases the risk of suffering chronic diseases such as, diabetes, arterial hypertension, stroke and some forms of cancer. We now know that adipose tissue, aside from being an energy store, is also an important endocrine and metabolic organ. Recently, new mechanisms that control obesity have been identified, such as the equilibrium between white and brown adipose tissue, the localization of adipose mass (visceral or ventral), and the presence of adipose and mesenchymal stem cells. In this review, we describe the implication of these stem cell types in the normal physiology and dysfunction of adipose tissue. These stem cells provide a potential target for modulating the response of the body to obesity and diabetes, as well as a potential tool for regenerative medicine. PMID: 21545335 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Adipose-Derived Mesenchymal Stem Cell Protects Kidneys against Ischemia-Reperfusion Injury through Suppressing Oxidative Stress and Inflammatory Reaction. J Transl Med. 2011 May 5;9(1):51 Authors: Chen YT, Sun CK, Lin YC, Chang LT, Chen YL, Tsai TH, Chung SY, Chua S, Kao YH, Yen CH, Shao PL, Chang KC, Leu S, Yip HK ABSTRACT: BACKGROUND: Reactive oxygen species are important mediators exerting toxic effects on various organs during ischemia-reperfusion (IR) injury. We hypothesized that adipose-derived mesenchymal stem cells (ADMSCs) protect the kidney against oxidative stress and inflammatory stimuli in rat during renal IR injury. METHODS: Adult male Sprague-Dawley (SD) rats (n=24) were equally randomized into group 1 (sham control), group 2 (IR plus culture medium only), and group 3 (IR plus immediate intra-renal administration of autologous ADMSCs, followed by intravenous ADMSCs at 6h and 24h after IR). The duration of ischemia was 1h, followed by 72 hours of reperfusion before the animals were sacrificed. RESULTS: Serum creatinine and blood urea-nitrogen levels and the degree of histological abnormalities were markedly lower in group 3 than in group 2 (all p<0.03). The mRNA expressions of inflammatory, oxidative stress, and apoptotic biomarkers were lower, whereas the anti-inflammatory, anti-oxidative, and anti-apoptotic biomarkers were higher in group 3 than in group 2 (all p<0.03). Immunofluorescent staining showed a higher number of CD31+, von Willebrand Factor+, and heme oxygenase (HO)-1+ cells in group 3 than in group 2 (all p<0.05). Western blot showed notably higher NAD(P)H quinone oxidoreductase 1 and HO-1 activities, two indicators of anti-oxidative capacity, in group 3 than those in group 2 (all p<0.04). Immunohistochemical staining showed higher glutathione peroxidase and glutathione reductase activities in group 3 than in group 2 (all p<0.02) CONCLUSION: ADMSC therapy minimized kidney damage after IR injury through suppressing oxidative stress and inflammatory response. PMID: 21545725 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Tenogenic differentiation of stem cells for tendon repair-what is the current evidence? J Tissue Eng Regen Med. 2011 May 5; Authors: Lui PP, Rui YF, Ni M, Chan KM Tendon/ligament injuries are very common in sports and other rigorous activities. Tendons regenerate and repair slowly and inefficiently in vivo after injury. The limited ability of tendon to self-repair and the general inefficiencies of current treatment regimes have hastened the motivation to develop tissue-engineering strategies for tissue repair. Of particular interest in recent years has been the use of adult mesenchymal stem cells (MSCs) to regenerate functional tendons and ligaments. Different sources of MSCs have been studied for their effects on tendon repair. However, ectopic bone and tumour formation has been reported in some special circumstances after transplantation of MSCs. The induction of MSCs to differentiate into tendon-forming cells in vitro prior to transplantation is a possible approach to avoid ectopic bone and tumour formation while promoting tendon repair. While there are reports about the factors that might promote tenogenic differentiation, the study of tenogenic differentiation is hampered by the lack of definitive biomarkers for tendons. This review aims to summarize the cell sources currently used for tendon repair as well as their advantages and limitations. Factors affecting tenogenic differentiation were summarized. Molecular markers currently used for assessing tenogenic differentiation or neotendon formation are summarized and their advantages and limitations are commented upon. Finally, further directions for promoting and assessing tenogenic differentiation of stem cells for tendon repair are discussed. Copyright © 2011 John Wiley & Sons, Ltd. PMID: 21548133 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Endothelial cell scaffolds generated by 3D direct writing of biodegradable polymer microfibers. Biomaterials. 2011 Mar;32(7):1872-9 Authors: Berry SM, Warren SP, Hilgart DA, Schworer AT, Pabba S, Gobin AS, Cohn RW, Keynton RS The engineering of large (thickness > 100 μm) tissues requires a microvascular network to supply nutrients and remove waste. To produce microvasculature in vitro, a scaffold is required to mechanically support and stimulate endothelial cell (EC) adhesion and growth. Scaffolds for ECs are currently produced by patterning polymers or other biomaterials into configurations which often possess isotropic morphologies such as porous films and fibrous mats. We propose a new "direct-write" process for fabricating scaffolds composed of suspended polymer microfibers that are precisely oriented in 3D, providing directional architecture for selectively guiding cell growth along a desired pathway. The diameters of the fibers produced with this process were predictably and repeatably controlled through modulation of the system parameters, enabling production of fibers with microvascular-scale diameters (5-20 μm) from a variety of biodegradable polymers. These scaffolds were successfully seeded with ECs, which conformed to the geometry of the fibers and proliferated over the course of one week. PMID: 21144583 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Cellular transduction gradients via vapor-deposited polymer coatings. Biomaterials. 2011 Mar;32(7):1809-15 Authors: Elkasabi YM, Lahann J, Krebsbach PH Spatiotemporal control of gene delivery, particularly signaling gradients, via biomaterials poses significant challenges because of the lack of efficient delivery systems for therapeutic proteins and genes. This challenge was addressed by using chemical vapor deposition (CVD) polymerization in a counterflow set-up to deposit copolymers bearing two reactive chemical gradients. FTIR spectroscopy verified the formation of compositional gradients. Adenovirus expressing a reporter gene was biotinylated and immobilized using the VBABM method (virus-biotin-avidin-biotin-materials). Sandwich ELISA confirmed selective attachment of biotinylated adenovirus onto copolymer gradients. When cultured on the adenovirus gradients, human gingival fibroblasts exhibited asymmetric transduction with full confluency. Importantly, gradient transduction occurred in both lateral directions, thus enabling more advanced delivery studies that involve gradients of multiple therapeutic genes. PMID: 21176953 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | ZNF145 improves differentiation potential of Human MSCs for cartilage regeneration and repair as an upstream factor of Sox9. Arthritis Rheum. 2011 May 5; Authors: Liu TM, Guo XM, Tan HS, Hui JH, Lim B, Lee EH OBJECTIVE.: Human mesenchymal stem cells (hMSCs) represent one of the most promising stem cell therapies for traumatic injury and age-related degenerative diseases involving cartilage. However, few genetic factors regulating chondrogenesis of MSCs have been identified. We have found that ZNF145, a transcriptional factor, was upregulated during three lineage differentiation of hMSCs. The present study was undertaken to validate whether this novel transcription factor ZNF145 is useful for the repair and regeneration of cartilage. METHOD.: hMSCs were transfected with lentiviral shRNA and overexpression of ZNF145, effects of ZNF145 on chondrogenesis was studied by QPCR and immunostaining. Microarray and transient expression was used to determine ZNF145 as an upstream factor of Sox9. Allogeneic transplantation of hMSCs into osteochondral defect of rats was performed to determine effects of ZNF145 on repair of cartilage in vivo. RESULT.: Small interfering RNA-mediated gene silencing of ZNF145 slowed down chondrogenesis whereas overexpression of ZNF145 enhanced chondrogenesis. Global gene expression profiling and transient expression of ZNF145 suggested that ZNF145 was upstream factor of Sox9, the master regulator of chondrogenesis. Moreover, allogeneic transplantation of human MSCs into osteochondral defects of rat knees showed that ZNF145-overexpressing MSCs repaired cartilage defects better and earlier than empty control MSCs. CONCLUSION.: These findings suggest that ZNF145 gene therapy may be a very useful strategy for improving the quality of cartilage regeneration and repair. PMID: 21547890 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Evaluation of the potential of novel PCL-PPDX biodegradable scaffolds as support materials for cartilage tissue engineering. J Tissue Eng Regen Med. 2011 May 5; Authors: Chaim IA, Sabino MA, Mendt M, Müller AJ, Ajami D Cartilage is a specialized tissue represented by a group of particular cells (the chondrocytes) and an abundant extracellular matrix. Because of the reduced regenerative capacity of this tissue, cartilage injuries are often difficult to handle. Nowadays tissue engineering has emerged as a very promising discipline, and biodegradable polymeric scaffolds are widely used as tissue supports. In cartilage injuries, the use of autologous chondrocyte implantation from non-affected cartilage zones has emerged as a very interesting technique, where chondrocytes are expanded in order to obtain a greater number of cells. Nevertheless, it has been reported that chondrocytes in bidimensional cultures suffer a dedifferentiation process. The present study sought, in the first place, to standardize a novel protocol in order to obtain primary cultures of chondrocytes from newborn rabbit hyaline cartilage from the xiphoid process. Second, the potential of porous three-dimensional (3D) biodegradable polymeric matrices as support materials for chondrocytes was evaluated: a novel poly(ε-caprolactone)-poly(p-dioxanone) (PCL-PPDX) blend in a 90:10 w:w ratio and poly(ε-caprolactone) (PCL). After achieving the standardization, a typical round-shaped chondrocyte morphology and the expression of collagen type II and aggrecan, evaluated by RT-PCR, were observed. Second-passage chondrocytes adhered effectively to these scaffolds, although cell growth at 7 days in culture was significantly less in the PCL-PPDX blend. After 3 weeks of culture on PCL-PPDX or PCL, the cells expressed collagen type II. The present study demonstrates the potential, unknown until now, of PCL-PPDX blend scaffolds in the field of cartilage tissue engineering. Copyright © 2011 John Wiley & Sons, Ltd. PMID: 21548137 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Development of bioactive photocrosslinkable fibrous hydrogels. J Biomed Mater Res A. 2011 May 4; Authors: Stephens-Altus JS, Sundelacruz P, Rowland ML, West JL Three-dimensional (3D) fibrous hydrogels were fabricated by blending two photoactive polymers, poly(ethylene glycol) diacrylate (PEGDA) and poly(vinyl alcohol) (PVA), and the resulting solution was electrospun. PEGDA is a commonly used hydrogel material for tissue engineering applications since its interaction with cells can be tuned by crosslinking in a variety of bioactive molecules including peptides and proteins. The PVA in these materials aids in fiber formation and stabilizes the fibrous network when hydrated. The average dry fiber diameter in the hydrogels was 1.02 μm and upon swelling, the fiber diameter increased approximately six-fold. Fibers were stable under cell culture conditions for up to 5 days. The adhesive ligand, RGDS, was readily incorporated into the fibrous network via the conjugation of RGDS to PEG-monoacrylate which was then crosslinked with the fibers. The bioactivity of the fibrous hydrogels was compared with peptide-modified PEGDA-based hydrogels. The two hydrogel materials had similar cell adhesion and viability. Cell morphology on the fibrous hydrogels was dendritic showing a more in vivo like representation, as compared to spread cell morphology on the PEGDA gels. The ability to generate 3D fibrous architectures in hydrogel systems opens up new areas of investigation in cell-material interactions and tissue formation. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID: 21548066 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Aligned 3D human aortic smooth muscle tissue via layer by layer technique inside microchannels with novel combination of collagen and oxidized alginate hydrogel. J Biomed Mater Res A. 2011 May 5; Authors: Rayatpisheh S, Poon YF, Cao Y, Feng J, Chan V, Chan-Park MB Tissue engineering of the small diameter blood vessel medial layer has been challenging. Recreation of the circumferentially aligned multilayer smooth muscle tissue has been one of the major technical difficulties. Some research has utilized cyclic stress to align smooth muscle cells (SMCs) but due to the long time conditioning needed, it was not possible to use primary human cells because of expeditious senescence occured. We demonstrate rapid buildup of a homogeneous relatively thick (30-40 μm) aligned smooth muscle tissue via layer by layer (LBL) technique within microchannels and a soft cell-adhesive hydrogel. Using a microchannelled scaffold with gapped microwalls, two layers of primary human SMCs separated by an interlayer hydrogel were cultured to confluence within the microchannels. The SMCs aligned along the microchannels because of the physically constraining microwalls. A novel double layered gel consisting of a mixture of pristine and oxidized alginate hydrogel coated with collagen was designed to place between each layer of cells, leading to a thicker tissue in a shorter time. The SMCs penetrated the soft thin interlayer hydrogel within 6 days of seeding of the 2nd cell layer so that the entire construct became more or less homogeneously populated by the SMCs. The unique LBL technique applied within the micropatterned scaffold using a soft cell-adhesive gel interlayer allows rapid growth and confluence of SMCs on 2D surface but at the same time aligns the cells and builds up multiple layers into a 3D tissue. This pseudo-3D buildup method avoids the typical steric resistance of hydrogel embedding. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID: 21548018 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Cultivated oral epithelial cells in oral cavity tissue losses treatment with autologous transplantation--case reports]. Pol Merkur Lekarski. 2011 Feb;30(176):121-5 Authors: Orzechowska-Wylegała' B, Dobrowolski D, Wowra B, Obuchowicz E, Bielecka A The rapid development of bioengineering in recent years enables to search for new therapies involving the use of tissue cultures. The aim of this paper is to study and apply the method of keratinocytes culture of mucous membrane on amniotic membrane to cover the losses in the oral cavity. PMID: 21544982 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Molecular plasma deposited peptides on anodized nanotubular titanium: An osteoblast density study. J Biomed Mater Res A. 2011 May 4; Authors: Balasundaram G, Shimpi TM, Sanow WR, Storey DM, Kitchell BS, Webster TJ A large amount of work is currently being conducted to design, fabricate, and characterize materials coated or immobilized with bioactive molecules for tissue engineering applications. Here, a novel method, molecular plasma deposition (MPD), is introduced with can efficiently coat materials with numerous bioactive peptides. Specifically, here, RGDS (arginine-glycine-aspartic acid-serine), KRSR (lysine-arginine-serine-arginine), and IKVAV (isoleucine-lysine-valine-alanine-valine) were coated on anodized nanotubular titanium using MPD. The anodized nanotubular titanium surfaces were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), and water contact angle measurements. Peptide coatings were examined by X-ray photoelectron spectroscopy (XPS) and an amine reactive fluorescence molecule, 3-(4 carboxybenzoyl)quinoline 2-carboxaldehyde (CBQCA). Electrospray ionization (ESI) was used to confirm peptide integrity. Osteoblast (bone-forming cell) density was determined on the materials of interest. Results confirmed peptide coatings and showed that the MPD RGDS and KRSR coatings on anodized nanotubular titanium increased osteoblast density compared with uncoated substrates and those coated with IKVAV and a control peptide (RGES) after 4 h and 7 days. SEM confirmed differences in the morphology of the attached cells. These results, to the best of our knowledge, are the first reports using MPD to efficiently create peptide coatings to increase osteoblast density on metals commonly used in orthopedics. Since MPD represents a quick, inexpensive, and versatile technique to coat implants with peptides, it should be further studied for numerous implant applications. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A: , 2011. PMID: 21548070 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Influence of the mesenchymal cell source on oral epithelial development. J Tissue Eng Regen Med. 2011 May 5; Authors: Kinikoglu B, Rovere MR, Haftek M, Hasirci V, Damour O The extent of the influence of mesenchymal tissue on epithelial development is still debated, and elucidation of epithelial-mesenchymal interactions should be of relevance for controlling normal as well as pathological growth and development. The aim of the present study was to elucidate the influence of the mesenchymal cell type on oral mucosa epithelial development in vitro, using tissue-engineering principles, by including three different sources for mesenchymal cell type, viz. oral mucosa, skin and cornea, each of them presenting a distinct type of epithelium in situ. We investigated epithelial-mesenchymal interactions, considering both morphological criteria and protein expression (filaggrin, keratin 10, keratin 12, keratin 13 and laminin 5). The results of the histology, immunohistochemistry and transmission electron microscopy of the three types of tissue-engineered constructs composed of mesenchymal cells of different sources (oral, dermal and corneal fibroblasts) and of the same oral epithelial cells showed that the mesenchymal cell source had a significant influence on the thickness and ultrastructure of the epithelium, but not on the differentiation of oral epithelial cells, which might be an intrinsic property of these cells due to their genetic programming. Copyright © 2011 John Wiley & Sons, Ltd. PMID: 21548135 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Engineering porous scaffolds using gas-based techniques. Curr Opin Biotechnol. 2011 May 3; Authors: Dehghani F, Annabi N Scaffolds are used in tissue engineering as a matrix for the seeding and attachment of human cells. The creation of porosity in three-dimensional (3D) structures of scaffolds plays a critical role in cell proliferation, migration, and differentiation into the specific tissue while secreting extracellular matrix components. These pores are used to transfer nutrients and oxygen and remove wastes produced from the cells. The lack of oxygen and nutrient supply impedes the cell migration more than 500μm from the surface. The physical properties of scaffolds such as porosity and pore interconnectivity can improve mass transfer and have a great impact on the cell adhesion and penetration into the scaffolds to form a new tissue. Various techniques such as electrospinning, freeze-drying, and solvent casting/salt leaching have been used to create porosity in scaffolds. The major issues in these methods include lack of 3D structure, control on pore size, and pore interconnectivity. In this review, we provide a brief overview of gas-based techniques that have been developed for creating porosity in scaffolds. PMID: 21546240 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The significance of pore microarchitecture in a multi-layered elastomeric scaffold for contractile cardiac muscle constructs. Biomaterials. 2011 Mar;32(7):1856-64 Authors: Park H, Larson BL, Guillemette MD, Jain SR, Hua C, Engelmayr GC, Freed LE Multi-layered poly(glycerol-sebacate) (PGS) scaffolds with controlled pore microarchitectures were fabricated, combined with heart cells, and cultured with perfusion to engineer contractile cardiac muscle constructs. First, one-layered (1L) scaffolds with accordion-like honeycomb shaped pores and elastomeric mechanical properties were fabricated by laser microablation of PGS membranes. Second, two-layered (2L) scaffolds with fully interconnected three dimensional pore networks were fabricated by oxygen plasma treatment of 1L scaffolds followed by stacking with off-set laminae to produce a tightly bonded composite. Third, heart cells were cultured on scaffolds with or without interstitial perfusion for 7 days. The laser-microablated PGS scaffolds exhibited ultimate tensile strength and strain-to-failure higher than normal adult rat left ventricular myocardium, and effective stiffnesses ranging from 220 to 290 kPa. The 7-day constructs contracted in response to electrical field stimulation. Excitation thresholds were unaffected by scaffold scale up from 1L to 2L. The 2L constructs exhibited reduced apoptosis, increased expression of connexin-43 (Cx-43) and matrix metalloprotease-2 (MMP-2) genes, and increased Cx-43 and cardiac troponin-I proteins when cultured with perfusion as compared to static controls. Together, these findings suggest that multi-layered, microfabricated PGS scaffolds may be applicable to myocardial repair applications requiring mechanical support, cell delivery and active implant contractility. PMID: 21144580 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Bone morphogenetic protein-2 in biodegradable gelatin and β-tricalcium phosphate sponges enhances the in vivo bone-forming capability of bone marrow mesenchymal stem cells. J Tissue Eng Regen Med. 2011 May 5; Authors: Tadokoro M, Matsushima A, Kotobuki N, Hirose M, Kimura Y, Tabata Y, Hattori K, Ohgushi H Bone marrow mesenchymal stem cells (MSCs) have been used for bone tissue engineering due to their osteogenic differentiation capability, but their application is controversial. To enhance their capability, we prepared biodegradable gelatin sponges incorporating β-tricalcium phosphate ceramics (GT sponge), which has been shown to possess excellent controlled drug-release properties. The GT sponge was used as a carrier for both rat MSCs and bone morphogenetic protein-2 (BMP-2) and osteogenic differentiation was assessed by subcutaneous implantation of four different kinds of implants, i.e. GT-alone, MSC-GT composites, BMP-GT composites and BMP-GT composites supplemented with MSCs (BMP-MSC-GT) in rats. Two weeks after implantation, histological sections showed new bone formation in the peripheral parts of the BMP-GT and in almost the total volume of the BMP-MSC-GT implants. After 4 weeks, histology as well as microCT analyses demonstrated extensive bone formation in BMP-MSC-GT implants. Gene expression and biochemical analyses of both alkaline phosphatase and bone-specific osteocalcin confirmed the histological findings. These results indicate that the combination of MSCs, GT and BMP synergistically enhances osteogenic capability and provides a rational basis for their clinical application in bone reconstruction. Copyright © 2011 John Wiley & Sons, Ltd. PMID: 21548136 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Human Periosteum Is a Source of Cells for Orthopaedic Tissue Engineering: A Pilot Study. Clin Orthop Relat Res. 2011 May 6; Authors: Ball MD, Bonzani IC, Bovis MJ, Williams A, Stevens MM BACKGROUND: Periosteal cells are important in embryogenesis, fracture healing, and cartilage repair and could provide cells for osteochondral tissue engineering. QUESTIONS/PURPOSE: We determined whether a population of cells isolated from human periosteal tissue contains cells with a mesenchymal stem cell (MSC) phenotype and whether these cells can be expanded in culture and used to form tissue in vitro. METHODS: We obtained periosteal tissue from six patients. Initial expression of cell surface markers was assessed using flow cytometry. Cells were cultured over 10 generations and changes in gene expression evaluated to assess phenotypic stability. Phenotype was confirmed using flow cytometry and colony-forming ability assays. Mineral formation was assessed by culturing Stro-1(-) and unsorted cells with osteogenic supplements. Three cell culture samples were used for a reverse transcription-polymerase chain reaction, four for flow cytometry, three for colony-forming assay, and three for mineralization. RESULTS: Primary cultures, containing large numbers of hematopoietic cells were replaced initially by Stro-1 and ALP-expressing immature osteoblastic cell types and later by ALP-expressing cells, which lacked Stro-1 and which became the predominant cell population during subculture. Approximately 10% of the total cell population continued to express markers for Stro1(+)/ALP(-) cells throughout. CONCLUSIONS: These data suggest periosteum contains a large number of undifferentiated cells that can differentiate into neotissue and persist despite culture in noncell-specific media for over 10 passages. CLINICAL RELEVANCE: Cultured periosteal cells may contribute to tissue formation and may be applicable for tissue engineering applications. PMID: 21547415 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Construction of tissue engineered nerve grafts and their application in peripheral nerve regeneration. Prog Neurobiol. 2011 Feb;93(2):204-30 Authors: Gu X, Ding F, Yang Y, Liu J Surgical repair of severe peripheral nerve injuries represents not only a pressing medical need, but also a great clinical challenge. Autologous nerve grafting remains a golden standard for bridging an extended gap in transected nerves. The formidable limitations related to this approach, however, have evoked the development of tissue engineered nerve grafts as a promising alternative to autologous nerve grafts. A tissue engineered nerve graft is typically constructed through a combination of a neural scaffold and a variety of cellular and molecular components. The initial and basic structure of the neural scaffold that serves to provide mechanical guidance and optimal environment for nerve regeneration was a single hollow nerve guidance conduit. Later there have been several improvements to the basic structure, especially introduction of physical fillers into the lumen of a hollow nerve guidance conduit. Up to now, a diverse array of biomaterials, either of natural or of synthetic origin, together with well-defined fabrication techniques, has been employed to prepare neural scaffolds with different structures and properties. Meanwhile different types of support cells and/or growth factors have been incorporated into the neural scaffold, producing unique biochemical effects on nerve regeneration and function restoration. This review attempts to summarize different nerve grafts used for peripheral nerve repair, to highlight various basic components of tissue engineered nerve grafts in terms of their structures, features, and nerve regeneration-promoting actions, and finally to discuss current clinical applications and future perspectives of tissue engineered nerve grafts. PMID: 21130136 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of oxygen levels on proteoglycan synthesis by intervertebral disc cells. Spine (Phila Pa 1976). 2011 Jan 15;36(2):E131-8 Authors: Mwale F, Ciobanu I, Giannitsios D, Roughley P, Steffen T, Antoniou J the response of cells from the annulus fibrosus (AF) and nucleus pulposus (NP) to varying oxygen (O2) concentrations was examined when cultured in alginate. PMID: 21057384 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
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