|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Several types of soft tissue sarcomas originate from the malignant transformation of adipose tissue-derived stem cells. Mol Med Report. 2010 May-Jun;3(3):441-8 Authors: Chen H, Zhang S, Wen JC, Zheng JK, Chen Q, Li WY, Wang PP, Ma L, Huang TH, Huang G, Yang LY The cellular origin of soft tissue sarcomas (STSs) is not fully understood. The cancer stem cell hypothesis presumes that tumors originate from the malignant transformation of stem cells. As a type of multipotent stem cell, adipose tissue-derived stromal/stem cells (ADSCs), which possess an unexpected degree of plasticity and often reside in other tissues, may represent a potential source of soft tissue sarcoma. To ascertain whether ADSCs are responsible for the formation of STSs, ADSCs from mice were cultured and treated with 3-methycholanthrene to derive transformed cells. These transformed ADSCs were then injected subcutaneously into immunodeficient mice to test their tumorigenic potential. We found that they generated several types of STSs, including synovial sarcoma, malignant fibrous histiocytoma and fibrosarcoma. This is the first study to report that ADSCs may be the potential initiating cells for synovial sarcoma. Our findings indicate that STSs might originate from malignantly transformed ADSCs. PMID: 21472259 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Extracellular matrix fibronectin stimulates the self-assembly of microtissues on native collagen gels. Tissue Eng Part A. 2010 Dec;16(12):3805-19 Authors: Sevilla CA, Dalecki D, Hocking DC Fibronectin is an adhesive glycoprotein that is polymerized into extracellular matrices via a tightly regulated, cell-dependent process. Here, we demonstrate that fibronectin matrix polymerization induces the self-assembly of multicellular structures in vitro, termed tissue bodies. Fibronectin-null mouse embryonic fibroblasts adherent to compliant gels of polymerized type I collagen failed to spread or proliferate. In contrast, addition of fibronectin to collagen-adherent fibronectin-null mouse embryonic fibroblasts resulted in a dose-dependent increase in cell number, and induced the formation of three-dimensional (3D) multicellular structures that remained adherent and well-spread on the native collagen substrate. An extensive fibrillar fibronectin matrix formed throughout the microtissue. Blocking fibronectin matrix polymerization inhibited both cell proliferation and microtissue formation, demonstrating the importance of fibronectin fibrillogenesis in triggering cellular self-organization. Cell proliferation, tissue body formation, and tissue body shape were dependent on both fibronectin and collagen concentrations, suggesting that the relative proportion of collagen and fibronectin fibrils polymerized into the extracellular matrix influences the extent of cell proliferation and the final shape of microtissues. These data demonstrate a novel role for cell-mediated fibronectin fibrillogenesis in the formation and vertical assembly of microtissues, and provide a novel approach for engineering complex tissue architecture. PMID: 20673131 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Mechanisms for Progenitor Cell-mediated Repair for Ischemic Heart Injury. Curr Stem Cell Res Ther. 2011 Apr 5; Authors: Li SC, Acevedo J, Schwartz PH, Wang L, Jiang H, Luo J, Pestell RG, Loudon WG, Chang AC Recent studies have shown that treatments involving injection of stem cells into animals with damaged cardiac tissue result in improved cardiac functionality. Clinical trials have reported conflicting results concerning the recellularization of post-infarct collagen scars. No clear mechanism has so far emerged to fully explain how injected stem cells, specifically the commonly used mesenchymal stem cells (MSC) and endothelium precursor cells (EPC), help heal a damaged heart. Clearly these injected stem cells must survive and thrive in the hypoxic environment that results after injury for any significant repair to occur. Here we discuss how ischemic preconditioning may lead to increased tolerance of stem cells to these harsh conditions and increase their survival and clinical potential after injection. As injected cells must reach the site in numbers large enough for repair to be functionally significant, homing mechanisms involved in stem cell migration are also discussed. We review the mechanisms of action stem cells may employ once they have arrived at their target destination such as: secretion of growth factors, differentiation into cardiomyocytes either to recellularize damaged tissue or strengthen the post-infarct scar or transdifferentiate into host cardiomyocytes as well as induced neovascularization. Tissue engineering may provide a standardized platform technology to produce clinically applicable stem cell products. PMID: 21466480 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | MicroRNA-155 Targets the SKI Gene in Human Melanoma Cell Lines. Pigment Cell Melanoma Res. 2011 Apr 6; Authors: Levati L, Pagani E, Romani S, Castiglia D, Piccinni E, Covaciu C, Caporaso P, Bondanza S, Antonetti FR, Bonmassar E, Martelli F, Alvino E, D'Atri S The SKI protein is a transcriptional co-regulator over-expressed in melanoma. Experimentally induced down-regulation of SKI inhibits melanoma cell growth in vitro and in vivo. Micro-RNAs (miRNAs) negatively modulate gene expression, and have been implicated in oncogenesis. We previously showed that microRNA-155 (miR-155) is down-regulated in melanoma cells as compared with normal melanocytes, and that its ectopic expression impairs proliferation and induces apoptosis. Here, we investigated whether miR-155 could mediate melanoma growth inhibition via SKI gene silencing. Luciferase reporter assays demonstrated that miR-155 interacted with SKI 3'UTR and impaired gene expression. Transfection of melanoma cells with miR-155 reduced SKI levels, while inhibition of endogenous miR-155 up-regulated SKI expression. Specifically designed small interfering RNAs reduced SKI expression and inhibited proliferation. However, melanoma cells over-expressing a 3'UTR-deleted SKI were still susceptible to the antiproliferative effect of miR-155. Our data demonstrate for the first time that SKI is a target of miR-155 in melanoma. However, impairment of SKI expression is not the leading mechanism involved in the growth-suppressive effect of miR-155 found in this malignancy. PMID: 21466664 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Optimised production of multifunctional microfibres by microfluidic chip technology for tissue engineering applications. Lab Chip. 2011 Apr 6; Authors: Mazzitelli S, Capretto L, Carugo D, Zhang X, Piva R, Nastruzzi C This paper describes a method for the production of alginate microfibres using glass-based microfluidic chips fabricated by a photolithography-wet etching procedure. The main focus of the work is the fabrication of a cell containing multifunctional microfibres which have great potential for applications in drug release formulations and tissue engineering scaffolds (to guide the regeneration of tissues in predefined sizes and shapes) providing cell structural support and immunoisolation. The key parameters, which critically influence the formation of microfibres and their geometries, were identified by a classical intuitive approach COST (Changing One Separate factor a Time). In particular, their effects on the microfibre diameter were investigated, which are directly associated with their functionalities relating to the implantation site, the nutrient availability and diffusion/transport of oxygen, essential nutrients, growth factors, metabolic waste and secretory products. The interplay between the alginate solution concentration, pumping rate and gelling bath concentration in controlling the diameter of the produced microfibres was investigated with a statistical approach by means of a "design of the experiments" (DoEs) optimization and screening. Finally, the processing impacts on cell viability, the cellular effect of wall thickness consistency and the spatial distribution of cells within the alginate microfibre were examined. We provide an approach for the production of alginate microfibres with controlled shape and content, which could be further developed for scaling up and working towards FDA approval. PMID: 21472178 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Role of substrate microstructure on osteogenic differentiation of mesenchymal stem cells. Conf Proc IEEE Eng Med Biol Soc. 2010;2010:3543-5 Authors: Jabbari E The objective of this work was to investigate the effect of substrate microstructure (planar versus microtubular geometry) on the extent of osteogenic differentiation of bone mesenchymal stem (BMS) cells. For laminated sheets, the BMS cell suspension was seeded on the sheets and cultured in complete osteogenic media. For laminated microtubes, the BMS cell suspension was injected in the tubes and allowed to incubate in osteogenic media. BMS cells cultured in osteon-mimetic microtubes had drastically higher ALPase activity and calcium content, compared to laminated sheets. The data demonstrate that the 3D environment of the microtubes profoundly affects osteogenic differentiation of the BMS cells, compared to the 2D laminated sheets. PMID: 21096823 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of microRNA modulation on bioartificial muscle function. Tissue Eng Part A. 2010 Dec;16(12):3589-97 Authors: Rhim C, Cheng CS, Kraus WE, Truskey GA Cellular therapies have recently employed the use of small RNA molecules, particularly microRNAs (miRNAs), to regulate various cellular processes that may be altered in disease states. In this study, we examined the effect of transient muscle-specific miRNA inhibition on the function of three-dimensional skeletal muscle cultures, or bioartificial muscles (BAMs). Skeletal myoblast differentiation in vitro is enhanced by inhibiting a proliferation-promoting miRNA (miR-133) expressed in muscle tissues. As assessed by functional force measurements in response to electrical stimulation at frequencies ranging from 0 to 20 Hz, peak forces exhibited by BAMs with miR-133 inhibition (anti-miR-133) were on average 20% higher than the corresponding negative control, although dynamic responses to electrical stimulation in miRNA-transfected BAMs and negative controls were similar to nontransfected controls. Immunostaining for alpha-actinin and myosin also showed more distinct striations and myofiber organization in anti-miR-133 BAMs, and fiber diameters were significantly larger in these BAMs over both the nontransfected and negative controls. Compared to the negative control, anti-miR-133 BAMs exhibited more intense nuclear staining for Mef2, a key myogenic differentiation marker. To our knowledge, this study is the first to demonstrate that miRNA mediation has functional effects on tissue-engineered constructs. PMID: 20670163 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Hydrogel microsphere encapsulation of a cell-based gene therapy system increases cell survival of injected cells, transgene expression, and bone volume in a model of heterotopic ossification. Tissue Eng Part A. 2010 Dec;16(12):3727-36 Authors: Olabisi RM, Lazard ZW, Franco CL, Hall MA, Kwon SK, Sevick-Muraca EM, Hipp JA, Davis AR, Olmsted-Davis EA, West JL Bone morphogenetic proteins (BMPs) are well known for their osteoinductive activity, yet harnessing this capacity remains a high-priority research focus. We present a novel technology that delivers high BMP-2 levels at targeted locations for rapid endochondral bone formation, enhancing our preexisting cell-based gene therapy system by microencapsulating adenovirus-transduced cells in nondegradable poly(ethylene glycol) diacrylate (PEGDA) hydrogels before intramuscular delivery. This study evaluates the in vitro and in vivo viability, gene expression, and bone formation from transgenic fibroblasts encapsulated in PEGDA microspheres. Fluorescent viability and cytotoxicity assays demonstrated >95% viability in microencapsulated cells. ELISA and alkaline phosphatase assays established that BMP-2 secretion and specific activity from microencapsulated AdBMP2-transduced fibroblasts were not statistically different from monolayer. Longitudinal transgene expression studies of AdDsRed-transduced fibroblasts, followed through live animal optical fluorescent imaging, showed that microencapsulated cells expressed longer than unencapsulated cells. When comparable numbers of microencapsulated AdBMP2-transduced cells were intramuscularly injected into mice, microcomputed tomography evaluation demonstrated that the resultant heterotopic bone formation was approximately twice the volume of unencapsulated cells. The data suggest that microencapsulation protects cells and prolongs and spatially distributes transgene expression. Thus, incorporation of PEGDA hydrogels significantly advances current gene therapy bone repair approaches. PMID: 20673027 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Evaluation of the biological behavior of decellularized pulmonary homografts: an experimental sheep model. Rev Bras Cir Cardiovasc. 2010 Sep;25(3):377-87 Authors: Navarro FB, Costa FD, Mulinari LA, Pimentel GK, Roderjan JG, Vieira ED, Noronha L, Miyague NI The cryopreserved homograft is a good valve substitute due attributes like excellent hemodynamics, low incidence of thromboembolic events, infection resistance and good mid-term durability. However, progressive homograft degeneration and fibrocalcification may occur, particularly in the childhood and young adults. Their antigenicity triggers an immunological reaction that plays an important role in their degeneration and failure. The decellularization process was proposed to decrease this antigenicity. By the action of detergents and enzymes, this process removes all cellular components from the homograft matrix, diminishing immunogenicity and probably delaying its degeneration. PMID: 21103747 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | The correlation between the internal structure and vascularization of controllable porous bioceramic materials in vivo: a quantitative study. Tissue Eng Part A. 2010 Dec;16(12):3791-803 Authors: Bai F, Wang Z, Lu J, Liu J, Chen G, Lv R, Wang J, Lin K, Zhang J, Huang X It is noticeable that porous architectural characteristics of the biomaterials play an important role in revascularization of the scaffold. However, there has been no consensus regarding the optimal conditions for vascularization, including macropore size, shape, interconnection, and the arrangement of macropores, due to the failure to accurately control porous structure of biomaterials. To investigate the effect of the porous structure parameters on vascularization of the biomaterials, an accurate control of these parameters is required. In this study, porous β-tricalcium phosphate (β-TCP) with accurately controlled pore parameters is fabricated by using assembled organic microspheres as templates combined with casting technique. Using this technique, we produced a series of disk-type β-TCP with variable pore sizes and variable interconnections to evaluate the influence of macropore size and interconnection on the vascularization of bioceramic material in vivo. The vascularization of β-TCP implanted in the rabbit model is evaluated by histomorphology and single photon emission computed tomography. The results showed that the pore parameters affect not only the size of the blood vessels growing into the porous structure but also the number of blood vessels formed in the pores of the bioceramic. The increase in pore size only resulted in an increase in size of the blood vessels growing into the macroporous of the bioceramic scaffolds. However, with the increase in size of interconnection, both the size and number of the blood vessels formed in the macroporous increased. Therefore, we conclude that the size of the interconnections is more important for vascularization in the scaffold compared with the pore size. On the other hand, there was no significant difference in vascularization in the scaffolds with pores size above 400 μm, and there was no marked increase in extent of vascularization with further increase in pore size above 400 μm, indicating that the upper limit of pore size for vascularization is 400 μm. PMID: 20673021 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | In-body optical stimulation formed connective tissue vascular grafts, "biotubes," with many capillaries and elastic fibers. J Artif Organs. 2010 Dec;13(4):235-40 Authors: Oie T, Yamanami M, Ishibashi-Ueda H, Kanda K, Yaku H, Nakayama Y The autologous biotube, developed by using in-body tissue architecture technology, is one of the most promising small-diameter vascular grafts in regenerative medicine. The walls of the biotubes obtained by a traditional silicone mold-based method were very thin, and this is still the primary obstacle while handling anastomosis, even though these biotubes have adequate pressure resistance ability. This pilot study showed the effect of optical stimulation of subcutaneous tissue formation in the body during the preparation of the biotubes. A blue light-emitting diode (LED) was embedded into a silicone rod as a mold. The biotube was prepared by placing the luminescent molds into the dorsal subcutaneous pouches of a pair of beagles (each weighing ~10 kg) for 2 weeks under photoirradiation. The wall thickness of the obtained biotubes was 506.9 ± 185.7 μm, which was remarkably more than that of the previous biotubes prepared by 2 months of embedding similarly in beagles' subcutaneous pouches (thickness, 77.2 ± 14.8 μm). Many capillaries with smooth muscle cells were infiltrated into the wall and concentrated in the internal layer. Interestingly, the formation of elastic fibers had already started along with collagen fibers, mostly with a regular circumferential orientation. The short-term in-body optical stimulation resulted in the rapid formation of a biotube. These phenomena will allow easy surgical handling and may induce vascular maturation in histology during the acute phase after implantation. PMID: 20882309 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Biotechnologically Produced Secondary Plant Metabolites for Cancer Treatment and Prevention. Curr Pharm Biotechnol. 2011 Apr 5; Authors: Korkina L, Kostyuk V Secondary metabolites of higher plants exert numerous effects on tumorigenesis, on tumor cells in vitro, tumors in experimental animals in vivo, interact with anti-cancer drugs, thus affecting positively or negatively their efficacy, and protect normal tissues of the host organism against adverse effects of anti-cancer therapies. The industrial development of pharmaceutical and nutraceutical products based on secondary plant metabolites is limited due to the following: (i) limited availability of their natural sources, (ii) concern about rare extinguishing plants, (iii) unavoidable contamination of plant extracts with environmental pollutants, (iv) seasonal variations in plant harvesting, (v) poor standardization of the final product due to variable conditions for plant growth, and (vi) difficulties of secondary metabolite extraction from the parts of grown plant. There is now steadily growing interest in the biotechnological approach to produce secondary metabolites using plant cell or plant tissue cultures. In the present review, biosynthesis of secondary metabolites and their role(s) in plant physiology will be briefly discussed; the biotechnological approach to active substances production in the plant cell and plant tissue cultures will be described; examples and mechanisms of cancer preventive and anti-cancer action of some biotechnologically produced plant metabolites will be provided; and future perspectives for biotechnologically produced plant-derived substances in the combined protocols for cancer treatment will be suggested. PMID: 21466424 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Nutrient diffusion and simple n(th)-order consumption in regenerative tissue and biocatalytic sensors. Biophys Chem. 2011 Feb 23; Authors: Belfiore LA, Floren ML, Volpato FZ, Paulino AT, Belfiore CJ This contribution addresses intra-tissue molar density profiles for nutrients, oxygen, growth factors, and other essential ingredients that anchorage-dependent cells require for successful proliferation on biocompatible surfaces. One-dimensional transient and steady state models of the reaction-diffusion equation are solved to correct a few deficiencies in the first illustrative example of diffusion and zeroth-order rates of consumption in tissues with rectangular geometry, as discussed in Ref. [(Griffith and Swartz, 2006) 1]. The functional form of the molar density profile for each species depends on geometry and the magnitude of the species-specific intra-tissue Damköhler number. The tissue's central core is reactant starved at high consumption rates and low rates of intra-tissue diffusion when the Damköhler number exceeds its geometry-sensitive critical value. Ideal tissue engineering designs avoid the diffusion-limited regime such that attached cells are exposed to all of the ingredients required for proliferation everywhere within a regenerative matrix. Analytical and numerical molar density profiles that satisfy the unsteady state modified diffusion equation with pseudo-homogeneous n(th)-order rates of intra-tissue consumption (i.e., n=0,1,2) allow one to (i) predict von Kármán-Pohlhausen mass transfer boundary layer thicknesses, measured inward from the external biomaterial surface toward its central core, and, most importantly, (ii) estimate the time required to achieve steady state conditions for regenerative tissue growth and biocatalytic sensing. PMID: 21470767 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Alpha-Amino Acid Containing Degradable Polymers as Functional Biomaterials: Rational Design, Synthetic Pathway and Biomedical Applications. Biomacromolecules. 2011 Apr 7; Authors: Sun H, Meng F, Dias AA, Hendriks M, Feijen J, Zhong Z Currently, biomedical engineering is rapidly expanding, especially in the areas of drug delivery, gene transfer, tissue engineering, and regenerative medicine. A prerequisite for further development is the design and synthesis of novel multi-functional biomaterials that are biocompatible and/or biologically active, are biodegradable with a controlled degradation rate, and have tunable mechanical properties. In the past decades, different types of α-amino acid-containing degradable polymers have been actively developed with the aim to obtain bio-mimicking functional biomaterials. The use of α-amino acids as building units for degradable polymers may offer several advantages: (i) imparting chemical functionality, such as hydroxyl, amine, carboxyl and thiol groups, which not only results in improved hydrophilicity and possible interactions with proteins and genes but also facilitates further modification with bioactive molecules (e.g. drugs or biological cues); (ii) possibly improving materials biological properties including cell-materials interactions (e.g. cell adhesion, migration) and degradability; (iii) enhancing thermal and mechanical properties; and (iv) providing metabolizable building units/blocks. In this paper, recent developments in the field of α-amino acid containing degradable polymers are reviewed. Firstly, synthetic approaches to prepare α-amino acid containing degradable polymers will be discussed. Subsequently, the biomedical applications of these polymers in areas such as drug delivery, gene delivery and tissue engineering will be reviewed. Finally, the future perspectives of α-amino acid containing degradable polymers will be evaluated. PMID: 21469742 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Serum Calcium-decreasing Factor, Caldecrin, Ameliorates Muscular Dystrophy in dy/dy Mice. In Vivo. 2011 Mar-Apr;25(2):157-63 Authors: Tomomura M, Fujii T, Sakagami H, Tomomura A Calcium signaling is important in muscular cells and abnormal Ca(2+) handling results in muscle damage. Caldecrin is a serum calcium-decreasing factor purified from pancreas. It is a chymotrypsin-type secretory protease, whereas the serum calcium-decreasing activity does not depend on its protease activity. Here, we evaluated the effect of caldecrin on dystrophia muscularis (dy/dy) mice. PMID: 21471529 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Suture augmentation following ACL injury to restore the function of the ACL, MCL, and medial meniscus in the goat stifle joint. J Biomech. 2011 Apr 4; Authors: Fisher MB, Jung HJ, McMahon PJ, Woo SL Functional tissue engineering (FTE) approaches have shown promise in healing an injured anterior cruciate ligament (ACL) of the knee. Nevertheless, additional mechanical augmentation is needed to maintain joint stability and appropriate loading of the joint while the ACL heals. The objective of this study was to quantitatively evaluate how mechanical augmentation using sutures restores the joint kinematics as well as the distribution of loading among the ACL, medial collateral ligament, and medial meniscus (MM) in response to externally applied loads. Eight goat stifle joints were tested on a robotic/universal force-moment sensor testing system under two loading conditions: (1) a 67N anterior tibial load (ATL) and (2) a 67N ATL with 100N axial compression. For each joint, four experimental conditions were tested at 30°, 60°, and 90° of flexion: the (1) intact and (2) ACL-deficient joint, as well as following (3) suture repair of the transected ACL, and (4) augmentation using sutures passed from the femur to the tibia. Under the 67N ATL, suture augmentation could restore the anterior tibial translation (ATT) to within 3mm of the intact joint (p>0.05), representing a 54-76% improvement over suture repair (p<0.05). With the additional axial compression, the ATT and in-situ forces of the sutures following suture augmentation remained 2-3 times closer to normal (p<0.05). Also, the in-situ forces in the MM were 58-73% lower (p<0.05). Thus, suture augmentation may be helpful in combination with FTE approaches for ACL healing by providing the needed initial joint stability while lowering the loads on the MM. PMID: 21470612 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Raman Micro-Spectroscopy as a Non-invasive Cell Viability Test. Methods Mol Biol. 2011;740:179-89 Authors: Verrier S, Zoladek A, Notingher I The number of techniques to identify, quantify and characterise cell death is rapidly increasing as more is known about the complex mechanisms underlying this process. However, most of these techniques are invasive and require preparation steps such as cell fixation, staining or protein extractions. Non-invasive analysis of living cells represents a key point in cell biology, e.g. in toxicology studies or in tissue engineering. In this chapter, we report the usefulness of Raman spectroscopy as a non-invasive method to distinguish cells at different stages of cell cycle and living cells from dead cells. Throughout two examples, we show the performance and the use of Raman spectroscopy as a new non-invasive method to assess cell viability. PMID: 21468979 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | The surface topography of the choroid plexus. Environmental, low and high vacuum scanning electron microscopy. Ann Anat. 2011 Mar 16; Authors: Mestres P, Pütz N, Garcia Gómez de Las Heras S, Poblete EG, Morguet A, Laue M Environmental scanning electron microscopy (ESEM) allows the examination of hydrated and dried specimens without a conductive metal coating which could be advantageous in the imaging of biological and medical objects. The aim of this study was to assess the performance and benefits of wet-mode and low vacuum ESEM in comparison to high vacuum scanning electron microscopy (SEM) using the choroid plexus of chicken embryos as a model, an organ of the brain involved in the formation of cerebrospinal fluid in vertebrates. Specimens were fixed with or without heavy metals and examined directly or after critical point drying with or without metal coating. For wet mode ESEM freshly excised specimens without any pre-treatment were also examined. Conventional high vacuum SEM revealed the characteristic morphology of the choroid plexus cells at a high resolution and served as reference. With low vacuum ESEM of dried but uncoated samples the structure appeared well preserved but charging was a problem. It could be reduced by a short beam dwell time and averaging of images or by using the backscattered electron detector instead of the gaseous secondary electron detector. However, resolution was lower than with conventional SEM. Wet mode imaging was only possible with tissue that had been stabilized by fixation. Not all surface details (e.g. microvilli) could be visualized and other structures, like the cilia, were deformed. In summary, ESEM is an additional option for the imaging of bio-medical samples but it is problematic with regard to resolution and sample stability during imaging. PMID: 21466950 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Osteochondral Interface Regeneration of Rabbit Mandibular Condyle With Bioactive Signal Gradients. J Oral Maxillofac Surg. 2011 Apr 4; Authors: Dormer NH, Busaidy K, Berkland CJ, Detamore MS PURPOSE: Tissue engineering solutions focused on the temporomandibular joint (TMJ) have expanded in number and variety during the past decade to address the treatment of TMJ disorders. The existing data on approaches for healing small defects in the TMJ condylar cartilage and subchondral bone, however, are sparse. The purpose of the present study was thus to evaluate the performance of a novel gradient-based scaffolding approach to regenerate osteochondral defects in the rabbit mandibular condyle. MATERIALS AND METHODS: Miniature bioactive plugs for regeneration of small mandibular condylar defects in New Zealand white rabbits were fabricated. The plugs were constructed from poly(d,l-lactic-co-glycolic acid) microspheres with a gradient transition between cartilage-promoting and bone-promoting growth factors. RESULTS: At 6 weeks of healing, the results suggested that the implants provided support for the neosynthesized tissue as evidenced by the histologic and 9.4 T magnetic resonance imaging findings. CONCLUSION: The inclusion of bioactive factors in a gradient-based scaffolding design is a promising new treatment strategy for focal defect repair in the TMJ. PMID: 21470747 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Confocal imaging protocols for live/dead staining in three-dimensional carriers. Methods Mol Biol. 2011;740:127-40 Authors: Gantenbein-Ritter B, Sprecher CM, Chan S, Illien-Jünger S, Grad S In tissue engineering, a variety of methods are commonly used to evaluate survival of cells inside tissues or three-dimensional (3D) carriers. Among these methods confocal laser scanning microscopy opened accessibility of 3D tissue using live cell imaging into the tissue or 3D scaffolds. However, although this technique is ideally applied to 3D tissue or scaffolds with thickness up to several millimetres, this application is surprisingly rare and scans are often done on slices with thickness <20 μm. Here, we present novel protocols for the staining of 3D tissue (e.g. intervertebral disc tissue) and scaffolds, such as fibrin gels or alginate beads. PMID: 21468974 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Smad1 and its target gene Wif1 coordinate BMP and Wnt signaling activities to regulate fetal lung development. Development. 2011 Mar;138(5):925-35 Authors: Xu B, Chen C, Chen H, Zheng SG, Bringas P, Xu M, Zhou X, Chen D, Umans L, Zwijsen A, Shi W Bone morphogenetic protein 4 (Bmp4) is essential for lung development. To define the intracellular signaling mechanisms by which Bmp4 regulates lung development, BMP-specific Smad1 or Smad5 was selectively knocked out in fetal mouse lung epithelial cells. Abrogation of lung epithelial-specific Smad1, but not Smad5, resulted in retardation of lung branching morphogenesis and reduced sacculation, accompanied by altered distal lung epithelial cell proliferation and differentiation and, consequently, severe neonatal respiratory failure. By combining cDNA microarray with ChIP-chip analyses, Wnt inhibitory factor 1 (Wif1) was identified as a novel target gene of Smad1 in the developing mouse lung epithelial cells. Loss of Smad1 transcriptional activation of Wif1 was associated with reduced Wif1 expression and increased Wnt/β-catenin signaling activity in lung epithelia, resulting in specific fetal lung abnormalities. This suggests a novel regulatory loop of Bmp4-Smad1-Wif1-Wnt/β-catenin in coordinating BMP and Wnt pathways to control fetal lung development. PMID: 21270055 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Alpha-Amino Acid Containing Degradable Polymers as Functional Biomaterials: Rational Design, Synthetic Pathway and Biomedical Applications. Biomacromolecules. 2011 Apr 7; Authors: Sun H, Meng F, Dias AA, Hendriks M, Feijen J, Zhong Z Currently, biomedical engineering is rapidly expanding, especially in the areas of drug delivery, gene transfer, tissue engineering, and regenerative medicine. A prerequisite for further development is the design and synthesis of novel multi-functional biomaterials that are biocompatible and/or biologically active, are biodegradable with a controlled degradation rate, and have tunable mechanical properties. In the past decades, different types of α-amino acid-containing degradable polymers have been actively developed with the aim to obtain bio-mimicking functional biomaterials. The use of α-amino acids as building units for degradable polymers may offer several advantages: (i) imparting chemical functionality, such as hydroxyl, amine, carboxyl and thiol groups, which not only results in improved hydrophilicity and possible interactions with proteins and genes but also facilitates further modification with bioactive molecules (e.g. drugs or biological cues); (ii) possibly improving materials biological properties including cell-materials interactions (e.g. cell adhesion, migration) and degradability; (iii) enhancing thermal and mechanical properties; and (iv) providing metabolizable building units/blocks. In this paper, recent developments in the field of α-amino acid containing degradable polymers are reviewed. Firstly, synthetic approaches to prepare α-amino acid containing degradable polymers will be discussed. Subsequently, the biomedical applications of these polymers in areas such as drug delivery, gene delivery and tissue engineering will be reviewed. Finally, the future perspectives of α-amino acid containing degradable polymers will be evaluated. PMID: 21469742 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Ceiling culture-derived proliferative adipocytes retain high adipogenic potential suitable for use as a vehicle for gene transduction therapy. Am J Physiol Cell Physiol. 2011 Apr 6; Authors: Asada S, Kuroda M, Aoyagi Y, Fukaya Y, Tanaka S, Konno S, Tanio M, Aso M, Satoh K, Okamoto Y, Nakayama T, Saito Y, Bujo H Adipose tissue is expected to provide a source of proliferative cells for regenerative medicine and cell-transplantation therapies using gene transfer manipulation. We have recently identified ceiling culture-derived proliferative adipocytes (ccdPAs) from the mature adipocyte fraction as cells suitable as a therapeutic gene vehicle because of their stable proliferative capacity. In this study, we examined the capability of adipogenic differentiation of the ccdPAs in comparison to stromal vascular fraction (SVF)-derived progenitor cells (adipose-derived stem cells, ASCs) with regard to their multipotential ability to be converted to another lineage, and therefore their potential to be used for regenerative medicine research. After in vitro passaging, the surface antigen profile and the basal levels of adipogenic marker genes of the ccdPAs were not obviously different from those of the ASCs. However, the ccdPAs showed increased lipid-droplet accumulation accompanied with higher adipogenic marker gene expression after stimulation of differentiation, compared with the ASCs. The higher adipogenic potential of the ccdPAs than the ASCs from the SVF was maintained for 42 days in culture. Furthermore, the difference in the adipogenic response was enhanced after partial stimulation without indomethacin. These results indicate that the ccdPAs retain a high adipogenic potential even after in vitro passaging, thus suggesting the commitment of ccdPAs to stable mature adipocytes after auto-transplantation, indicating that they may have potential for use in regenerative and gene-manipulated medicine. PMID: 21471463 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The US Army Dental and Trauma Research Detachment: now part of the Army Institute of Surgical Research. US Army Med Dep J. 2011 Jan-Mar;:68-9 Authors: Mellus DE, Amaya J PMID: 21409765 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Stage-specific signaling through TGFβ family members and WNT regulates patterning and pancreatic specification of human pluripotent stem cells. Development. 2011 Mar;138(5):861-71 Authors: Nostro MC, Sarangi F, Ogawa S, Holtzinger A, Corneo B, Li X, Micallef SJ, Park IH, Basford C, Wheeler MB, Daley GQ, Elefanty AG, Stanley EG, Keller G The generation of insulin-producing β-cells from human pluripotent stem cells is dependent on efficient endoderm induction and appropriate patterning and specification of this germ layer to a pancreatic fate. In this study, we elucidated the temporal requirements for TGFβ family members and canonical WNT signaling at these developmental stages and show that the duration of nodal/activin A signaling plays a pivotal role in establishing an appropriate definitive endoderm population for specification to the pancreatic lineage. WNT signaling was found to induce a posterior endoderm fate and at optimal concentrations enhanced the development of pancreatic lineage cells. Inhibition of the BMP signaling pathway at specific stages was essential for the generation of insulin-expressing cells and the extent of BMP inhibition required varied widely among the cell lines tested. Optimal stage-specific manipulation of these pathways resulted in a striking 250-fold increase in the levels of insulin expression and yielded populations containing up to 25% C-peptide+ cells. PMID: 21270052 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Plasmid-based transient human stromal cell-derived factor-1 gene transfer improves cardiac function in chronic heart failure. Gene Ther. 2011 Apr 7; Authors: Sundararaman S, Miller TJ, Pastore JM, Kiedrowski M, Aras R, Penn MS We previously demonstrated that transient stromal cell-derived factor-1 alpha (SDF-1) improved cardiac function when delivered via cell therapy in ischemic cardiomyopathy at a time remote from acute myocardial infarction (MI) rats. We hypothesized that non-viral gene transfer of naked plasmid DNA-expressing hSDF-1 could similarly improve cardiac function. To optimize plasmid delivery, we tested SDF-1 and luciferase plasmids driven by the cytomegalovirus (CMV) promoter with (pCMVe) or without (pCMV) translational enhancers or α myosin heavy chain (pMHC) promoter in a rodent model of heart failure. In vivo expression of pCMVe was 10-fold greater than pCMV and pMHC expression and continued over 30 days. We directly injected rat hearts with SDF-1 plasmid 1 month after MI and assessed heart function. At 4 weeks after plasmid injection, we observed a 35.97 and 32.65% decline in fractional shortening (FS) in control (saline) animals and pMHC-hSDF1 animals, respectively, which was sustained to 8 weeks. In contrast, we observed a significant 24.97% increase in animals injected with the pCMVe-hSDF1 vector. Immunohistochemistry of cardiac tissue revealed a significant increase in vessel density in the hSDF-1-treated animals compared with control animals. Increasing SDF-1 expression promoted angiogenesis and improved cardiac function in rats with ischemic heart failure along with evidence of scar remodeling with a trend toward decreased myocardial fibrosis. These data demonstrate that stand-alone non-viral hSDF-1 gene transfer is a strategy for improving cardiac function in ischemic cardiomyopathy.Gene Therapy advance online publication, 7 April 2011; doi:10.1038/gt.2011.18. PMID: 21472007 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Deltonin, a Steroidal Saponin, Inhibits Colon Cancer Cell Growth in Vitro and Tumor Growth in Vivo via Induction of Apoptosis and Antiangiogenesis. Cell Physiol Biochem. 2011;27(3-4):233-42 Authors: Tong QY, Qing Y, Shu D, He Y, Zhao YL, Li Y, Wang ZL, Zhang SY, Xing ZH, Xu C, Wei YQ, Huang W, Wu XH Deltonin, a steroidal saponin, isolated from Dioscorea zingiberensis Wright (DZW), has shown high-cytotoxic activity in cancer cells. However, its mechanisms and in vivo anti-cancer effects remain unknown. In the present study, we evaluated the effects and explored the anti-tumor mechanisms of deltonin on a panel of colon cancer cell lines and in a mouse model of murine colon cancer C26. Deltonin had more cytotoxic effect on C26 cells than 5-fluorouracil had, promoting dramatic G2-M phase arrest and apoptosis in C26 cells in a concentration-dependent manner; oral administration of deltonin significantly inhibited the tumor growth and prolonged survival of the tumor bearing mice. The deltonin treatment caused a noticeable apoptosis in tumor tissue, which associated with increased levels of Bax, activated caspase-3, caspase-9, and cleaved poly (ADPribose) polymerase, decreased pro-caspase-8, pro-caspase-9, Bcl-2 expression levels and extracellular signal-regulated kinase-1/2 activity; and dose-dependently inhibit angiogenesis. In conclusion, the findings in this study demonstrated that deltonin is an effective natural agent for cancer therapy, which may be mediated, in part, by induction of apoptosis, as well as involve mitogen-activated protein kinase pathways, and inhibition of angiogenesis. PMID: 21471712 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Retinoid X receptors as a potential avenue for regenerative medicine in multiple sclerosis. Expert Rev Neurother. 2011 Apr;11(4):467-8 Authors: Huang JK, Jarjour AA, Ffrench-Constant C, Franklin RJ PMID: 21469916 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Resistance or sensitivity of Wilms' tumor to anti-FZD7 antibody highlights the Wnt pathway as a possible therapeutic target. Oncogene. 2011 Apr 7;30(14):1664-80 Authors: Pode-Shakked N, Harari-Steinberg O, Haberman-Ziv Y, Rom-Gross E, Bahar S, Omer D, Metsuyanim S, Buzhor E, Jacob-Hirsch J, Goldstein RS, Mark-Danieli M, Dekel B Wilms' tumor (WT), the most frequent renal solid tumor in children, has been linked to aberrant Wnt signaling. Herein, we demonstrate that different WTs can be grouped according to either sensitivity or resistance to an antibody (Ab) specific to frizzled7 (FZD7), a Wnt receptor. In the FZD7-sensitive WT phenotype, the Ab induced cell death of the FZD7(+) fraction, which in turn depleted primary WT cultures of their clonogenic and sphere-forming cells and decreased in vivo proliferation and survival on xenografting to the chick chorio-allantoic-membrane. In contrast, FZD7-resistant WT in which no cell death was induced showed a different intra-cellular route of the Ab-FZD7 complex compared with sensitive tumors and accumulation of β-catenin. This coincided with a low sFRP1 and DKK1 (Wnt inhibitors) expression pattern, restored epigenetically with de-methylating agents, and lack of β-catenin or WTX mutations. The addition of exogenous DKK1 and sFRP1 to the tumor cells enabled the sensitization of FZD7-resistant WT to the FZD7 Ab. Finally, although extremely difficult to achieve because of dynamic cellular localization of FZD7, sorting of FZD7(+) cells from resistant WT, showed them to be highly clonogenic/proliferative, overexpressing WT 'stemness' genes, emphasizing the importance of targeting this fraction. FZD7 Ab therapy alone or in combination with Wnt pathway antagonists may have a significant role in the treatment of WT via targeting of a tumor progenitor population. PMID: 21472018 [PubMed - in process] | | | | | | | | | |  | |  | |  |
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