|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Chondrogenesis from human placenta-derived mesenchymal stem cells (hPMSCs) in 3D scaffolds for cartilage tissue engineering. Tissue Eng Part A. 2011 Feb 1; Authors: Hsu SH, Huang TB, Cheng SJ, Weng SY, Tsai CL, Tseng CS, Chen DC, Liu TY, Fu KY, Yen BL Human placenta-derived mesenchymal stem cells (hPMSCs) represent a promising source of stem cells. The application of hPMSCs in cartilage tissue engineering, however, was less reported. In this study, hPMSCs were grown in a three-dimensional (3D) environment for cartilage tissue formation in vitro. To select proper scaffolds for 3D culture of mesenchymal stem cells (MSCs), rat adipose-derived mesenchymal stem cells (rMSCs) were initially employed to optimize the composition and condition of the 3D environment. The suitability of a poly(D,L-lactide-co-glycolide) (PLGA) precision scaffold previously developed for seeding and culture of primary chondrocytes was tested for MSCs. It was established that MSCs had to be embedded in alginate gel before seeded in the PLGA precision scaffold for cartilage-like tissue formation. The inclusion of nano-sized calcium deficient hydroxyapatite (nCDHA) and/or a recombinant protein containing arginine-glycine-aspartate (RGD) into the alginate gel enhanced the chondrogenesis for both rMSCs and hPMSCs. The amount of extracellular matrix (ECM) such as glycosaminoglycan (GAG) and type II collagen accumulated during a period of 21 days was found to be the greatest for hPMSCs embedded in the alginate/nCDHA/RGD gel, injected and cultivated in the precision scaffold. Meanwhile, histological analyses revealed the lacunae formation and ECM production from the seeded hPMSCs. Comparing human bone marrow-derived mesenchymal stem cells (hBMSCs) and hPMSCs grown in the previous composite scaffolds, the secretion of GAG was twice as higher for hPMSCs as that for hBMSCs. It was concluded that the alginate/nCDHA/RGD mixed gel in the aforementioned system could provide a 3D environment for the chondrogenesis of hPMSCs, while the PLGA precision scaffold could provide the dimensional stability of the whole construct. This study also suggested that hPMSCs, when grown in a suitable scaffold, may be a good source of stem cells for building up the tissue engineered cartilage. PMID: 21284540 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Resorption of cartilage grafts in rhinoplasty: fundamental basis]. Rev Laryngol Otol Rhinol (Bord). 2010;131(2):83-8 Authors: De Gabory L, Fricain JC, Stoll D Resorption of the autologous cartilage graft of the nasal dorsum is a problem which concerns all rhinoplasticians. Their rate of resorption is estimated between 20 to 30% of the graft volume and can occur with no means of prevention from the side of the surgeon. The goal of this article is to highlight, through a short review of the literature, the current data regarding the composition of the septal cartilage, its healing process and the progress made in cartilaginous tissue engineering to adapt our surgical technique. Cartilaginous tissue engineering does not yet have the abilities to provide a replacement septal cartilage with the same molecular composition, the same mechanical properties and devoid of volume loss after implantation and in spite of a certain progress, autologous cartilage grafts are still making the headlines. However to avoid the resorption of the latter and to preserve their volume, it seems necessary to avoid crushing them so as not to compromise chondrocyte viability and proliferation. Cutting-out millimeter-length dices seems more adapted to preserve cellular viability but remains insufficient because of the low healing capacities of the cartilage. Diced-cartilage wrapped with connective tissue seems an elegant and efficient solution over the long run to safeguard their volume and to harmonize contours and irregularities of the dorsum. PMID: 21284222 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Decreased Mechanical Properties of Heart Valve Tissue Constructs Cultured in Platelet Lysate as Compared to Fetal Bovine Serum. Tissue Eng Part C Methods. 2011 Feb 2; Authors: van Geemen D, Riem Vis P, Soekhradj-Soechit S, Sluijter J, de Liefde-van Beest M, Kluin J, Bouten C In autologous heart valve tissue engineering, there is an ongoing search for alternatives of Fetal Bovine Serum (FBS). Human platelet-lysate (PL) might be a promising substitute. In the present paper we aimed to examine the tissue formation, functionality, and mechanical properties of engineered 3-D tissue constructs cultured in PL as a substitute for FBS. Our results show that tissue constructs that were cultured in PL and FBS produce similar amounts of collagen, GAGs and collagen crosslinks, and that the cellular phenotype remains unchanged. Nevertheless, mechanical testing showed that the ultimate tensile strength in PL constructs was on average approximately three times lower as compared to FBS (0.25 MPa vs. 0.74 MPa respectively, p < 0.01), and also the elastic modulus was almost three times lower (1.33 MPa of PL constructs vs. 3.94 MPa of FBS constructs, p < 0.01). Additional tests indicated that this difference might be explained by different collagen fiber architecture possibly due to increased production of matrix-degrading proteases by cells cultured in PL. In summary, our results indicate that PL is not preferred for the culture of strong heart valve tissue constructs. PMID: 21284560 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A comparison between osteogenic differentiation of human unrestricted somatic stem cells and mesenchymal stem cells from bone marrow and adipose tissue. Biotechnol Lett. 2011 Feb 2; Authors: Shafiee A, Seyedjafari E, Soleimani M, Ahmadbeigi N, Dinarvand P, Ghaemi N To evaluate the potential of three stem cells for cell therapy and tissue engineering applications, the biological behavior and osteogenic capacity of the newly introduced cord-blood-derived, unrestricted somatic stem cells (USSC) were compared with those of mesenchymal stem cells isolated from bone marrow (BM-MSC) and adipose tissue (AT-MSC). There was no significant difference between the rates of proliferation of the three stem cells. During osteogenic differentiation, alkaline phosphatase (ALP) activity peaked on day 7 in USSC compared to BM-MSC which showed the maximum value of ALP activity on day 14. However, BM-MSC had the highest ALP activity and mineralization during osteogenic induction. In addition, AT-MSC showed the lowest capacity for mineralization during differentiation and had the lowest ALP activity on days 7 and 14. Although AT-MSC expressed higher levels of collagen type I, osteonectin and BMP-2 in undifferentiated state, but these genes were expressed higher in BM-MSC during differentiation. BM-MSC also expressed higher levels of ALP, osteocalcin and Runx2 during induction. Taking together, BM-MSC showed the highest capacity for osteogenic differentiation and hold promising potential for bone tissue engineering and cell therapy applications. PMID: 21287233 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Differential expression of sclerostin in adult and juvenile mouse calvariae. Plast Reconstr Surg. 2011 Feb;127(2):595-602 Authors: Kwan MD, Quarto N, Gupta DM, Slater BJ, Wan DC, Longaker MT : An understanding of the molecular mechanisms controlling bone formation is central to skeletal tissue engineering efforts. The observation that immature animals are able to heal calvarial defects while adult animals are not has proven to be a useful tool for examining these mechanisms. Thus, the authors compared expression of sclerostin, a bone inhibitor, between the calvariae of juvenile and adult mice. PMID: 21285764 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Preparation of TGF-β1-conjugated biodegradable pluronic F127 hydrogel and its application with adipose-derived stem cells. J Control Release. 2010 Oct 1;147(1):84-91 Authors: Jung HH, Park K, Han DK In this study, a composite hydrogel using Pluronic F127 derivatives and crosslinked hyaluronic acid (X-HA) was investigated, exploring the benefits in the induction of chondrogenic differentiation of human adipose-derived stem cells (ASCs). F127 was chemically modified through a series of reactions that produced multiple F127 derivatives. A chondrogenic growth factor, transforming growth factor-beta 1 (TGF-β1) was then coupled to the heparin-conjugated F127. X-HA was used as a physical stabilizer of the composite hydrogel (X-HA/F127). The chemical structures of F127 derivatives were analyzed using (1)H-NMR and ATR-FTIR. Sol-gel transition of the composite hydrogel was identified at body temperature. The conjugated TGF-β1 was moderately released in vitro from the composite hydrogel. Cell viability of human ASCs in the hydrogels was about 50% after in vitro culture for 3 days. As the ASCs/hydrogel were injected into nude mice subcutaneously, DAPI staining of the retrieved constructs showed that ASCs were dispersed through the hydrogel matrix. From the immunofluorescent staining of type II collagen, the TGF-conjugated group exhibited more active green signals than the others. In addition, when those constructs were loaded into the full-thickness defect of rabbit knee articular cartilage, Alcian blue staining identified the formation of cartilaginous matrix from the TGF-conjugated hydrogel. The present work indicated that X-HA/F127 composite hydrogel was thermoreversible and biodegradable, and that the TGF-conjugated hydrogel could be effective in inducing chondrogenesis of human ASCs. PMID: 20599451 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | In vitro study in stimulating the secretion of angiogenic growth factors of strontium-doped calcium polyphosphate for bone tissue engineering. J Mater Sci Mater Med. 2011 Feb 2; Authors: Liu F, Zhang X, Yu X, Xu Y, Feng T, Ren D Angiogenesis of tissue-engineered bone remains a limited factor for the engineering of larger bone tissue constructs. Attempts to stimulate angiogenesis, using recombinant protein or gene transfer of angiogenic growth factors, have been proposed; however, these approaches have been associated with some problems regarding such as complex technique, expensive prices as well as safety problems and short half-life of angiogenic growth factors. This study was performed to determine the ability of strontium-doped calcium polyphosphate (SCPP) to induce angiogenesis via researching its effect on the mRNA expressions and protein secretion of VEGF and bFGF in/from cultured osteoblasts (ROS17/2.8 cells). We cultured osteoblasts with SCPP scaffolds containing various doses of strontium as well as calcium polyphosphate (CPP) scaffold. Through the detection of MTT and SEM, we have found that SCPP could promote cell proliferation and maintain their morphology. The results of RT-PCR and ELISA indicated that, compared with those in CPP group, the mRNA expression as well as protein levels of VEGF and bFGF in/from cultured osteoblasts were dose-dependent increasing in response to increasing strontium before reaching the peak in SCPP groups, and 8% SCPP showed the optimal promoting role. Therefore, SCPP containing proper dose of strontium could be served as a potential biomaterial with stimulating angiogenesis in bone tissue engineering and bone repair. PMID: 21287239 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Cell- and Gene-Based Therapeutic Strategies for Periodontal Regenerative Medicine. J Periodontol. 2011 Feb 2; Authors: Rios HF, Lin Z, Oh B, Park CH, Giannobile WV Inflammatory periodontal diseases are a leading cause of tooth loss and are linked to multiple systemic conditions such as cardiovascular disease and stroke. The reconstruction of the support and function of affected tooth-supporting tissues represents an important therapeutic endpoint for periodontal regenerative medicine. Today, our improved understanding of periodontal biology coupled with current advances in scaffolding matrices has introduced novel treatments that employ cell and gene therapy to enhance periodontal tissue reconstruction and its biomechanical integration. Cell and gene delivery technologies have the potential to overcome the limitations associated with existing periodontal therapies, and may provide a new direction in sustainable inflammation control and more predictable tissue regeneration of supporting alveolar bone, periodontal ligament and cementum. The purpose of this review is to provide clinicians with the current status of these early stage and emerging cell- and gene-based therapeutics in periodontal regenerative medicine as well as introduce their future application in clinical periodontal therapeutics. This paper will conclude with prospects on the application of cell and gene tissue engineering technologies for reconstructive periodontology. PMID: 21284553 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fabrication and cell affinity of biomimetic structured PLGA/articular cartilage ECM composite scaffold. J Mater Sci Mater Med. 2011 Feb 3; Authors: Zheng X, Yang F, Wang S, Lu S, Zhang W, Liu S, Huang J, Wang A, Yin B, Ma N, Zhang L, Xu W, Guo Q An ideal scaffold for cartilage tissue engineering should be biomimetic in not only mechanical property and biochemical composition, but also the morphological structure. In this research, we fabricated a composite scaffold with oriented structure to mimic cartilage physiological morphology, where natural nanofibrous articular cartilage extracellular matrix (ACECM) was used to mimic the biochemical composition, and synthetic PLGA was used to enhance the mechanical strength of ACECM. The composite scaffold has well oriented structure and more than 89% of porosity as well as about 107 μm of average pore diameter. The composite scaffold was compared with ACECM and PLGA scaffolds. Cell proliferation test showed that the number of MSCs in ACECM and composite scaffolds was noticeably bigger than that in PLGA scaffold, which was coincident with results of SEM observation and cell viability staining. The water absorption of ACECM and composite scaffolds were 22.1 and 10.2 times respectively, which was much higher than that of PLGA scaffolds (3.8 times). The compressive modulus of composite scaffold in hydrous status was 1.03 MPa, which was near 10 times higher than that of hydrous ACECM scaffold. The aforementioned results suggested that the composite scaffold has the potential for application in cartilage tissue engineering. PMID: 21287238 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Modeling interlamellar interactions in angle-ply biologic laminates for annulus fibrosus tissue engineering. Biomech Model Mechanobiol. 2011 Feb 3; Authors: Nerurkar NL, Mauck RL, Elliott DM Mechanical function of the annulus fibrosus of the intervertebral disc is dictated by the composition and microstructure of its highly ordered extracellular matrix. Recent work on engineered angle-ply laminates formed from mesenchymal stem cell (MSC)-seeded nanofibrous scaffolds indicates that the organization of collagen fibers into planes of alternating alignment may play an important role in annulus fibrosus tissue function. Specifically, these engineered tissues can resist tensile deformation through shearing of the interlamellar matrix as layers of collagen differentially reorient under load. In the present work, a hyperelastic constitutive model was developed to describe the role of interlamellar shearing in reinforcing the tensile response of biologic laminates, and was applied to experimental results from engineered annulus constructs formed from MSC-seeded nanofibrous scaffolds. By applying the constitutive model to uniaxial tensile stress-strain data for bilayers with three different fiber orientations, material parameters were generated that characterize the contributions of extrafibrillar matrix, fibers, and interlamellar shearing interactions. By 10 weeks of in vitro culture, interlamellar shearing accounted for nearly 50% of the total stress associated with uniaxial extension in the anatomic range of ply angle. The model successfully captured changes in function with extracellular matrix deposition through variations in the magnitude of model parameters with culture duration. This work illustrates the value of engineered tissues as tools to further our understanding of structure-function relations in native tissues and as a test-bed for the development of constitutive models to describe them. PMID: 21287395 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Organic/Inorganic Hybrid Network Structure Nanocomposite Scaffolds Based on Grafted Chitosan for Tissue Engineering. Acta Biomater. 2011 Jan 29; Authors: Depan D, Surya PK, Girase B, Misra RD We describe the first study of structure-processing-property relationship in organic/inorganic hybrid network structure nanocomposite scaffolds based on grafted chitosan for bone tissue engineering. Chitosan was first grafted with propylene oxide to form hydroxypropylated chitosan, which was subsequently linked with ethylene glycol functionalized nano-hydroxyapatite (f-nHA), to form an organic/inorganic network structure. The resulting scaffold was characterized by a highly porous structure and significantly superior physico-chemical, mechanical, and biological properties compared to pure chitosan. The scaffolds exhibited high modulus, controlled swelling behavior, and reduced water uptake, but the water retention ability was similar to pure chitosan scaffold. MTT assay studies confirmed the non-cytotoxic nature of the scaffolds and enabled degradation products to be analyzed. The nanocomposite scaffolds were biocompatible and supported adhesion, spreading, proliferation and viability of osteoblasts cells. Furthermore, the cells were able to infiltrate and colonize into the pores of the scaffolds and establish cell-cell interactions. The study suggests that hydroxypropylation of chitosan and forming a network structure with nano-inorganic constituent is a promising approach for enhancing physico-chemical, functional, and biological properties for utilization in bone-tissue engineering applications. PMID: 21284959 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Regeneration and Functional Recovery of Intrapelvic Nerves Removed During Extensive Surgery by a New Artificial Nerve Conduit: A Breakthrough to Radical Operation for Locally Advanced and Recurrent Rectal Cancers. J Gastrointest Surg. 2011 Feb 2; Authors: Tsujimoto H, Nakamura T, Miki T, Kubo T, Otsuji E, Yamagishi H, Hagiwara A PURPOSE: In the current strategy against locally advanced and recurrent rectal cancers possibly involving intrapelvic nerves, there has been a serious dilemma between extensive surgery and limited surgery. The former can attain high tumor curability by sacrificing the nerve functions while the latter prioritizes the patient quality of life by preserving the nerve functions but with a compromised curability. Here we present a new surgical strategy for locally advanced and recurrent rectal cancers, which realize both high tumor curability and good quality of life. METHODS: A new artificial nerve conduit (polyglycolic acid collagen tube) developed by in site tissue engineering technology was applied to recovery the disturbed functions after removing the nerves from 11 patients undergoing extensive surgery for intrapelvic advanced or recurrent colorectal cancers. The reconstructed nerves included eight autonomic nerves which are essential for the genitourinary function and three somatic nerves which control the sensation and mobility of the legs. RESULTS: Out of ten cases followed up more than 2 years and evaluated fully, eight including two report cases showed a functional recovery of the disturbed autonomic and somatic nerves clinically. The nerve function started to recover from 3 to 6 months after the operation and continued to improve with times. No specific complications associated with the nerve repair have been noted. CONCLUSIONS: The new strategy utilizing the nerve conduit can be a breakthrough in radical operations for locally advanced and recurrent rectal cancers to resolve the problems between tumor curability and the patient quality of life. PMID: 21287289 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | "Deep-media culture condition" promoted lumen formation of endothelial cells within engineered three-dimensional tissues in vitro. J Artif Organs. 2011 Feb 2; Authors: Sekiya S, Shimizu T, Yamato M, Okano T In the field of tissue engineering, the induction of microvessels into tissues is an important task because of the need to overcome diffusion limitations of oxygen and nutrients within tissues. Powerful methods to create vessels in engineered tissues are needed for creating real living tissues. In this study, we utilized three-dimensional (3D) highly cell dense tissues fabricated by cell sheet technology. The 3D tissue constructs are close to living-cell dense tissue in vivo. Additionally, creating an endothelial cell (EC) network within tissues promoted neovascularization promptly within the tissue after transplantation in vivo. Compared to the conditions in vivo, however, common in vitro cell culture conditions provide a poor environment for creating lumens within 3D tissue constructs. Therefore, for determining adequate conditions for vascularizing engineered tissue in vitro, our 3D tissue constructs were cultured under a "deep-media culture conditions." Compared to the control conditions, the morphology of ECs showed a visibly strained cytoskeleton, and the density of lumen formation within tissues increased under hydrostatic pressure conditions. Moreover, the increasing expression of vascular endothelial cadherin in the lumens suggested that the vessels were stabilized in the stimulated tissues compared with the control. These findings suggested that deep-media culture conditions improved lumen formation in engineered tissues in vitro. PMID: 21286767 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | In vivo performance of bilayer hydroxyapatite scaffolds for bone tissue regeneration in the rabbit radius. J Mater Sci Mater Med. 2011 Feb 2; Authors: Guda T, Walker JA, Pollot BE, Appleford MR, Oh S, Ong JL, Wenke JC The objective of this study was to investigate the in vivo biomechanical performance of bone defects implanted with novel bilayer hydroxyapatite (HAp) scaffolds that mimic the cortical and cancellous organization of bone. The scaffolds maintained architectural continuity in a rabbit radius segmental defect model and were compared to an untreated defect group (negative control) and autologous bone grafts (positive control). Micro-CT evaluations indicated total bone and scaffold volume in the experimental group was significantly greater than the defect group but lesser than the autologous bone graft treatment. The flexural toughness of the scaffold and the autograft groups was significantly greater than the flexural toughness of the defect group. Interestingly, the absolute density of the bone mineral as well as calcium to phosphorus (Ca/P) ratio in that mineral for the scaffold and autograft contralateral bones was significantly higher than those for the defect contralaterals suggesting that the scaffolds contributed to calcium homeostasis. It was concluded from this study that new bone regenerated in the bilayer HAp scaffolds was comparable to the empty defects and while the HAp scaffolds provided significant increase in modulus when compared to empty defect and their flexural toughness was comparable to autografts after 8 weeks of implantation. PMID: 21287244 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Differential expression of sclerostin in adult and juvenile mouse calvariae. Plast Reconstr Surg. 2011 Feb;127(2):595-602 Authors: Kwan MD, Quarto N, Gupta DM, Slater BJ, Wan DC, Longaker MT : An understanding of the molecular mechanisms controlling bone formation is central to skeletal tissue engineering efforts. The observation that immature animals are able to heal calvarial defects while adult animals are not has proven to be a useful tool for examining these mechanisms. Thus, the authors compared expression of sclerostin, a bone inhibitor, between the calvariae of juvenile and adult mice. PMID: 21285764 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Functional genomics: new insights into the 'function' of low levels of gene expression in stem cells. Curr Genomics. 2010 Aug;11(5):354-8 Authors: Hipp JA, Hipp JD, Atala A, Soker S Understanding the global gene expression profile of stem cells and their multilineage differentiation will be essential for their ultimate therapeutic application. Efforts to characterize stem cells have relied on analyzing the genome-wide expression profiles that are biased towards the identification of genes that display the most pronounced differential expression. Rather than being viewed as a "blank" state, recent studies suggest that stem cells express low levels of multiple lineage specific genes prior to differentiation, a phenomenon known as "lineage priming." It is not likely that low levels of lineage-specific genes produce sufficient amounts of differentiation factors, but rather to provide rapid transcription to a wide range of lineage programs prior to differentiation. Thus, stem cell differentiation may involve the elimination of other potential pathways and the activation of a specific lineage program. PMID: 21286313 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Cell- and Gene-Based Therapeutic Strategies for Periodontal Regenerative Medicine. J Periodontol. 2011 Feb 2; Authors: Rios HF, Lin Z, Oh B, Park CH, Giannobile WV Inflammatory periodontal diseases are a leading cause of tooth loss and are linked to multiple systemic conditions such as cardiovascular disease and stroke. The reconstruction of the support and function of affected tooth-supporting tissues represents an important therapeutic endpoint for periodontal regenerative medicine. Today, our improved understanding of periodontal biology coupled with current advances in scaffolding matrices has introduced novel treatments that employ cell and gene therapy to enhance periodontal tissue reconstruction and its biomechanical integration. Cell and gene delivery technologies have the potential to overcome the limitations associated with existing periodontal therapies, and may provide a new direction in sustainable inflammation control and more predictable tissue regeneration of supporting alveolar bone, periodontal ligament and cementum. The purpose of this review is to provide clinicians with the current status of these early stage and emerging cell- and gene-based therapeutics in periodontal regenerative medicine as well as introduce their future application in clinical periodontal therapeutics. This paper will conclude with prospects on the application of cell and gene tissue engineering technologies for reconstructive periodontology. PMID: 21284553 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | One and four layer acellular bladder matrix for fascial tissue reconstruction. J Mater Sci Mater Med. 2011 Feb 1; Authors: Eberli D, Atala A, Yoo JJ To determine whether the use of multiple layers of acellular bladder matrix (ABM) is more suitable for the treatment of abdominal wall hernia than a single layered ABM. The feasibility, biocompatibility and mechanical properties of both materials were assessed and compared. Biocompatibility testing was performed on 4 and 1 layered ABM. The matrices were used to repair an abdominal hernia model in 24 rabbits. The animals were followed for up to 3 months. Immediately after euthanasia, the implant site was inspected and samples were retrieved for histology, scanning electron microscopy and biomechanical studies. Both acellular biomaterials demonstrated excellent biocompatibility. At the time of retrieval, there was no evidence of infection. The matrices demonstrated biomechanical properties comparable to native tissue. Three hernias (25%) were found in the single layer ABM group and only 1 hernia (8%) was found in the 4 layer ABM group. Histologically, the matrix structure was intact and the cell density within the matrices decreased with time. The dominant cell type present within the matrices shifted from lymphocytes to fibroblasts over time. Both ABMs maintained adequate strength over time when used for hernia repair, and there was an extremely low incidence of adhesion formation. The single layer ABM showed enhanced cellular integration, while the 4 layer ABM reduced hernia formation. Either of these matrices may be useful as an off-the-shelf biomaterial for patients requiring fascial repair. PMID: 21286788 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A comparison between osteogenic differentiation of human unrestricted somatic stem cells and mesenchymal stem cells from bone marrow and adipose tissue. Biotechnol Lett. 2011 Feb 2; Authors: Shafiee A, Seyedjafari E, Soleimani M, Ahmadbeigi N, Dinarvand P, Ghaemi N To evaluate the potential of three stem cells for cell therapy and tissue engineering applications, the biological behavior and osteogenic capacity of the newly introduced cord-blood-derived, unrestricted somatic stem cells (USSC) were compared with those of mesenchymal stem cells isolated from bone marrow (BM-MSC) and adipose tissue (AT-MSC). There was no significant difference between the rates of proliferation of the three stem cells. During osteogenic differentiation, alkaline phosphatase (ALP) activity peaked on day 7 in USSC compared to BM-MSC which showed the maximum value of ALP activity on day 14. However, BM-MSC had the highest ALP activity and mineralization during osteogenic induction. In addition, AT-MSC showed the lowest capacity for mineralization during differentiation and had the lowest ALP activity on days 7 and 14. Although AT-MSC expressed higher levels of collagen type I, osteonectin and BMP-2 in undifferentiated state, but these genes were expressed higher in BM-MSC during differentiation. BM-MSC also expressed higher levels of ALP, osteocalcin and Runx2 during induction. Taking together, BM-MSC showed the highest capacity for osteogenic differentiation and hold promising potential for bone tissue engineering and cell therapy applications. PMID: 21287233 [PubMed - as supplied by publisher] | | | | | | | | | |  | |  | |  |
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