|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | The role of collagen receptors Endo180 and DDR-2 in the foreign body reaction against non-crosslinked collagen and gelatin. Biomaterials. 2010 Nov 9; Authors: Ye Q, Harmsen MC, Ren Y, Bank RA Despite the use of collagen-derived scaffolds in regenerative medicine, little is known about the degradation mechanisms of these scaffolds in vivo. Non-crosslinked dermal sheep (NDSC) and gelatin disks were implanted subcutaneously in mice. NDSC disks showed a very low degradation rate, despite the presence of high numbers of macrophages and the influx of neutrophils. This was attributed to the presence of the matrix metalloproteinase inhibitor TIMP-1. The limited degradation occurred mainly in the later stages of the foreign body reaction, and could be attributed to (1) phagocytosis by macrophages due to a co-expression of Endo180 and MT1-MMP on these cells (intracellular degradation) and (2) the presence of MMP-13 due to an upregulation of the expression of the DDR-2 receptor (extracellular degradation). In contrast, gelatin disks degraded quickly, due to the efficient formation of large giant cells as well as the presence of MMP-13; the inhibitor TIMP-1 was absent. The DDR-2 receptor was not expressed in the gelatin disks. Endo180 and MT1-MMP were expressed, but at most times no co-expression was seen. We conclude that the physical state of collagen (native or denatured) had a dramatic outcome on the degradation rate and provoked a completely different foreign body reaction. PMID: 21071084 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Rescue of Lethal Hepatic Failure by Hepatized Lymph Nodes in Mice. Gastroenterology. 2010 Nov 8; Authors: Hoppo T, Komori J, Manohar R, Stolz DB, Lagasse E BACKGROUND & AIMS:: Hepatocyte transplantation is a potential therapeutic approach for liver disease. However, most patients with chronic hepatic damage have cirrhosis and fibrosis, which limit the potential for cell-based therapy of the liver. The development of an ectopic liver as an additional site of hepatic function represents a new approach for patients with an end-stage liver disease. We investigated the development and function of liver tissue in lymph nodes in mice with liver failure. METHODS:: Hepatocytes were isolated from 8 to 12-week-old mice and transplanted by intraperitoneal injection into 8- to 12-week-old Fah-/-mice, a model of the human liver disease tyrosinemia type I. Survival was monitored and the locations and functions of the engrafted liver cells were determined. RESULTS:: Lymph nodes of Fah-/-mice were colonized by transplanted hepatocytes; Fah+ hepatocytes were detected adjacent to the CD45+ lymphoid cells of the lymphatic system. Ten weeks after transplantation, these mice had substantial improvements in serum levels of transaminases, bilirubin, and amino acids. Homeostatic expansion of donor hepatocytes in lymph nodes rescued the mice from lethal hepatic failure. CONCLUSIONS:: Functional ectopic liver tissue in lymph nodes rescues mice from lethal hepatic disease; lymph nodes might therefore be used as sites for hepatocyte transplantation. All studies published in Gastroenterology are embargoed until 3PM ET of the day they are published as corrected proofs on-line. Studies cannot be publicized as accepted manuscripts or uncorrected proofs. PMID: 21070777 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of 3D-scaffold formation on differentiation and survival in human neural progenitor cells. Biomed Eng Online. 2010 Nov 11;9(1):70 Authors: Ortinau S, Schmich J, Block S, Liedmann A, Jonas L, Weiss DG, Helm CA, Rolfs A, Frech MJ ABSTRACT: BACKGROUND: 3D-scaffolds have been shown to direct cell growth and differentiation in many different cell types, with the formation and functionalisation of the 3D-microenviroment being important in determining the fate of the embedded cells. Here we used a hydrogel-based scaffold to investigate the influences of matrix concentration and functionalisation with laminin on the formation of the scaffolds, and the effect of these scaffolds on human neural progenitor cells cultured within them. METHODS: In this study we used different concentrations of the hydrogel-based matrix PuraMatrix. In some experiments we functionalised the matrix with laminin I. The impact of concentration and treatment with laminin on the formation of the scaffold was examined with atomic force microscopy. Cells from a human fetal neural progenitor cell line were cultured in the different matrices, as well as in a 2D culture system, and were subsequently analysed with antibody stainings against neuronal markers. In parallel, the survival rate of the cells was determined by a live/dead assay. RESULTS: Atomic force microscopy measurements demonstrated that the matrices are formed by networks of isolated PuraMatrix fibres and aggregates of fibres. An increase of the hydrogel concentration led to a decrease in the mesh size of the scaffolds and functionalisation with laminin promoted aggregation of the fibres (bundle formation), which further reduces the density of isolated fibres. We showed that laminin-functionalisation is essential for human neural progenitor cells to build up 3D-growth patterns, and that proliferation of the cells is also affected by the concentration of matrix. In addition we found that 3D-cultures enhanced neuronal differentiation and the survival rate of the cells compared to 2D-cultures. CONCLUSIONS: Taken together, we have demonstrated a direct influence of the 3D-scaffold formation on the survival and neuronal differentiation of human neural progenitor cells. These findings emphasize the importance of optimizing 3D-scaffolds protocols prior to in vivo engraftment of stem and progenitor cells in the context of regenerative medicine. PMID: 21070668 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Morphometric Analysis of the Human Scalp Hair Follicle: Practical Implications for the Hair Transplant Surgeon and Hair Regeneration Studies. Dermatol Surg. 2010 Nov 11; Authors: Jimenez F, Izeta A, Poblet E BACKGROUND The bulge stem cell region is a structure important for the regeneration of the pilosebaceous unit. Measurements of the different compartments of a hair follicle may have implications in hair transplantation and hair regeneration studies. OBJECTIVE To measure the length of the different portions of the occipital scalp hair and to estimate at what depth they are located. METHODS AND MATERIAL Hair follicles from the occipital scalp were obtained from 29 individuals. Measurements were performed on digital pictures using a software imaging system. Antibody anticytokeratin (CK), 15 was used as a bulge stem cell marker. RESULTS The mean length of a scalp hair follicle is 4.16 mm. The infundibulum measures 0.76 mm, the isthmus 0.89 mm, and the inferior portion 2.5 mm. The insertion of the arrector pili muscle is located 1.65 mm deep. CK15 immunoreactivity starts at a depth of 1 mm and extends down to 1.8 mm. CONCLUSION The ideal depth for the trichophytic procedure is to cut the wound edge at a depth of less than 1 mm to avoid the bulge zone. The data provided can serve as an objective anatomical reference in hair regeneration studies using horizontally transected follicles. The authors have indicated no significant interest with commercial supporters. PMID: 21070465 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A Randomized Clinical Trial on Preventing Pressure Ulcers with Wheelchair Seat Cushions. J Am Geriatr Soc. 2010 Nov 10; Authors: Brienza D, Kelsey S, Karg P, Allegretti A, Olson M, Schmeler M, Zanca J, Geyer MJ, Kusturiss M, Holm M OBJECTIVES: To determine the efficacy of skin protection wheelchair seat cushions in preventing pressure ulcers in the elderly nursing home population. DESIGN: Clinical trial with participants assigned at random to a skin protection or segmented foam cushion. Two hundred thirty-two participants were recruited between June 2004 and May 2008 and followed for 6 months or until pressure ulcer incidence. SETTING: Twelve nursing homes. PARTICIPANTS: Nursing home residents aged 65 and older who were using wheelchairs for 6 or more hours per day and had a Braden score of 18 or less and a combined Braden activity and mobility score of 5 or less. Participants were recruited from a referred sample. INTERVENTION: All participants were provided with a fitted wheelchair and randomized into skin protection (SPC, n=113) or segmented foam (SFC, n=119) cushion groups. The SPC group received an air, viscous fluid and foam, or gel and foam cushion. The SFC group received a 7.6-cm crosscut foam cushion. MEASUREMENTS: Pressure ulcer incidence over 6 months for wounds near the ischial tuberosities (IT ulcers) were measured. Secondary analysis was performed on combined IT ulcers and ulcers over the sacrum and coccyx (sacral ulcers). RESULTS: One hundred eighty participants reached a study end point, and 42 were lost to follow-up. Ten did not receive the intervention. There were eight (6.7%) IT ulcers in the SFC group and one (0.9%) in the SPC group (P=.04). There were 21 (17.6%) combined IT and sacral ulcers in the SFC group and 12 (10.6%) in the SPC group (P=.14). CONCLUSION: Skin protection cushions used with fitted wheelchairs lower pressure ulcer incidence for elderly nursing home residents and should be used to help prevent pressure ulcers. PMID: 21070197 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A prevalent mutation with founder effect in Spanish Recessive Dystrophic Epidermolysis Bullosa families. BMC Med Genet. 2010;11:139 Authors: Cuadrado-Corrales N, Sánchez-Jimeno C, García M, Escámez MJ, Illera N, Hernández-Martín A, Trujillo-Tiebas MJ, Ayuso C, Del Rio M BACKGROUND: Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a genodermatosis caused by more than 500 different mutations in the COL7A1 gene and characterized by blistering of the skin following a minimal friction or mechanical trauma.The identification of a cluster of RDEB pedigrees carrying the c.6527insC mutation in a specific area raises the question of the origin of this mutation from a common ancestor or as a result of a hotspot mutation. The aim of this study was to investigate the origin of the c.6527insC mutation. METHODS: Haplotypes were constructed by genotyping nine single nucleotides polymorphisms (SNPs) throughout the COL7A1 gene. Haplotypes were determined in RDEB patients and control samples, both of Spanish origin. RESULTS: Sixteen different haplotypes were identified in our study. A single haplotype cosegregated with the c.6527insC mutation. CONCLUSION: Haplotype analysis showed that all alleles carrying the c.6527insC mutation shared the same haplotype cosegregating with this mutation (CCGCTCAAA_6527insC), thus suggesting the presence of a common ancestor. PMID: 20920254 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Assessment of heat shock protein (HSP60, HSP72, HSP90, and HSC70) expression in cultured limbal stem cells following air lifting. Mol Vis. 2010;16:1680-8 Authors: Ebrahimi M, Mohammadi P, Daryadel A, Baharvand H OBJECTIVES: The aim of this study is to create an ex vivo model to examine the expression of major heat-shock protein (HSP) families; HSP60, HSP72, and HSP90, and heat-shock cognate 70 (HCS70) at the mRNA and protein level in differentiating corneal cells from limbal stem cells (LSC) following air exposure. METHODS: Limbal biopsies taken from cadaveric normal human limbus were cultivated as explants on human amniotic membrane (HAM) and plastic dish (PD). Corneal differentiation was induced by air lifting for 16 days. The expression of putative LSC markers (P63 and ATP-binding cassette G2 [ABCG2]), corneal markers (keratin 3 [K3/12] and connexin 43 [CX43]), and HSP60, HSP72, HSP90, and HSC70 were tested by RT-PCR, immunofluorescence, and flow cytometry pre- and post-air exposure. Fresh limbal and corneal tissues were used as control groups. RESULTS: Air lifting induced corneal differentiation with a decrease in the number of P63(+) cells and an increase in the number of K3(+)/CX43(+) cells, which characterized transient amplifying cells (TACs). Moreover, denuded HAM provided a superior niche for LSC proliferation and phenotype maintenance in vitro. Additionally, we have evidence that expressions of HSC70 as well as HSP72 were enhanced through corneal differentiation and HSP90 post-air lifting in vitro and in vivo. HSP60, however, was not detected in either LSC or corneal cells, in vivo and in vitro. CONCLUSIONS: These results suggest that corneal differentiation following air exposure may regulate HSP72 and HSC70 expression. In addition, HSP72 and HSP90 may protect LSC and corneal cells against oxidative stress. PMID: 20806039 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Human pluripotent stem cells in drug discovery and predictive toxicology. Biochem Soc Trans. 2010 Aug;38(4):1051-7 Authors: Laustriat D, Gide J, Peschanski M Human pluripotent stem cells are a biological resource most commonly considered for their potential in cell therapy or, as it is now called, 'regenerative medicine'. However, in the near future, their most important application for human health may well be totally different, as they are more and more envisioned as opening new routes for pharmacological research. Pluripotent stem cells indeed possess the main attributes that make them theoretically fully equipped for the development of cell-based assays in the fields of drug discovery and predictive toxicology. These cells are characterized by: (i) an unlimited self-renewal capacity, which make them an inexhaustible source of cells; (ii) the potential to differentiate into any cell phenotype of the body at any stage of differentiation, with probably the notable exception, however, of the most mature forms of many lineages; and (iii) the ability to express genotypes of interest via the selection of donors, whether they be of embryonic origin, through pre-implantation genetic diagnosis, or adults, by genetic reprogramming of somatic cells, so-called iPSCs (induced pluripotent stem cells). In the present review, we provide diverse illustrations of the use of pluripotent stem cells in drug discovery and predictive toxicology, using either human embryonic stem cell lines or iPSC lines. PMID: 20659002 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Gene-expression analysis of polyI:C-stimulated primary human conjunctival epithelial cells. Br J Ophthalmol. 2010 Nov;94(11):1528-32 Authors: Ueta M, Mizushima K, Yokoi N, Naito Y, Kinoshita S BACKGROUND: The authors previously reported that human ocular surface epithelium expressed TLR3 and that its ligand polyI:C stimulated the secretion of IL-6, IL-8 and IFN-β. In this study, to examine comprehensive effects of polyI:C stimulation of primary human conjunctival epithelial cells (PHCjECs), the authors performed a gene-expression analysis of the polyI:C-stimulated PHCjECs using oligonucleotide microarrays, GeneChip. METHODS: The transcripts upregulated upon polyI:C stimulation in PHCjECs from two individuals were examined using GeneChip. Eleven new upregulated transcripts of interest were confirmed by quantitative real-time PCR (RT-PCR), and seven proteins produced by those transcripts were examined by ELISA or immunoblot analysis in PHCjECs from three other individuals, respectively. RESULTS: GeneChip analysis showed that 150 transcripts were upregulated more than threefold and that 47 transcripts were upregulated more than 10-fold upon polyI:C stimulation in the PHCjECs. Eleven of the 47 upregulated transcripts (CXCL11, RIG-I, IL28A, CXCL10, CCL5, CCL4, MDA5, IL7R, TSLP, CCL20 and ICAM-1) were significantly upregulated upon polyI:C stimulation by quantitative RT-PCR, and the levels of seven proteins of the transcripts CXCL11, CXCL10, CCL5, CCL20, TSLP, RIG-I and MDA5 were confirmed by ELISA or immunoblot analysis to increase significantly in polyI:C-stimulated PHCjECs. CONCLUSIONS: Our results might show that TLR3 of conjunctival epithelium could not only induce antiviral innate immune responses but also regulate the allergic reactions. PMID: 20657019 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Concise review: multiple niches for hematopoietic stem cell regulations. Stem Cells. 2010 Jul;28(7):1243-9 Authors: Oh IH, Kwon KR Two types of stem cell niches in bone marrow (BM), endosteal osteoblastic, and vascular niches are involved in the microenvironmental regulation of hematopoietic stem cells (HSCs). Recently, redundant features of the two niches were identified, based on their common cellular origins or chemical mediators being produced in each niche. In contrast, studies have also revealed that HSCs are localized differentially in the niches with respect to their distinct functional status, and that the biological activity of each niche is differentially influenced by extrinsic conditions. An important question is, therefore, whether these two niches play distinct roles in regulating HSCs and whether they respond differentially to environmental stimuli/stress for "compartmentalized" niche organization in BM. In this review, recent discoveries related to the characteristics of each type of niche and their common or unique features are discussed, along with the possibility of multiniche regulation of HSCs in BM. PMID: 20517982 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Human stem cell therapy in ischaemic stroke: a review. Age Ageing. 2010 Nov 10; Authors: Banerjee S, Williamson D, Habib N, Gordon M, Chataway J Stroke is a leading cause of death and disability. Globally, 15 million people suffer a stroke each year, of whom more than 5 million die, and a further 5 million are left permanently disabled. Current treatment options offer modest benefits, and there is a pressing need for new and effective treatments. Stem cell therapy is a well-established treatment modality for various haematological diseases, with its use now being explored in different disease processes, including various neurological diseases, as well as vascular conditions such as ischaemic heart disease and peripheral vascular disease. Promising results have been seen in animal models of stroke, with evidence of significant functional benefits. Translation to the bedside, however, is in its early stages. This review will discuss the scientific background to stem cell therapy in ischaemic stroke, including evidence from current clinical trials. PMID: 21071454 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Feasibility of combination allogeneic stem cell therapy for spinal cord injury: a case report. Int Arch Med. 2010 Nov 11;3(1):30 Authors: Ichim TE, Solano F, Lara F, Paris E, Ugalde F, Paz Rodriguez J, Minev B, Bogin V, Ramos F, Woods EJ, Murphy MP, Patel AN, Harman RJ, Riordan NH ABSTRACT: Cellular therapy for spinal cord injury (SCI) is overviewed focusing on bone marrow mononuclear cells, olfactory ensheathing cells, and mesenchymal stem cells. A case is made for the possibility of combining cell types, as well as for allogeneic use. We report a 29 year old male who suffered a crush fracture of the L1 vertebral body, lacking lower sensorimotor function, being a score A on the ASIA scale. Stem cell therapy comprised of intrathecal administration of allogeneic umbilical cord blood expanded CD34 and umbilical cord matrix MSC was performed 5 months, 8 months, and 14 months after injury. Cell administration was well tolerated with no adverse effects observed. Neuropathic pain subsided from intermittent 10/10 to once a week 3/10 VAS. Recovery of muscle, bowel and sexual function was noted, along with a decrease in ASIA score to "D". This case supports further investigation into allogeneic-based stem cell therapies for SCI. PMID: 21070647 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Microfluidic Devices for Bioapplications. Small. 2010 Nov 11; Authors: Yeo LY, Chang HC, Chan PP, Friend JR Harnessing the ability to precisely and reproducibly actuate fluids and manipulate bioparticles such as DNA, cells, and molecules at the microscale, microfluidics is a powerful tool that is currently revolutionizing chemical and biological analysis by replicating laboratory bench-top technology on a miniature chip-scale device, thus allowing assays to be carried out at a fraction of the time and cost while affording portability and field-use capability. Emerging from a decade of research and development in microfluidic technology are a wide range of promising laboratory and consumer biotechnological applications from microscale genetic and proteomic analysis kits, cell culture and manipulation platforms, biosensors, and pathogen detection systems to point-of-care diagnostic devices, high-throughput combinatorial drug screening platforms, schemes for targeted drug delivery and advanced therapeutics, and novel biomaterials synthesis for tissue engineering. The developments associated with these technological advances along with their respective applications to date are reviewed from a broad perspective and possible future directions that could arise from the current state of the art are discussed. PMID: 21072867 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Biomimetic Materials for Medical Application Through Enzymatic Modification. Adv Biochem Eng Biotechnol. 2010 Nov 12; Authors: Gentile P, Chiono V, Tonda-Turo C, Sartori S, Ciardelli G Living organisms synthesize functional materials, based on proteins and polysaccharides, using enzyme-catalyzed reactions. According to the biomimetic approach, biomaterial matrices for tissue engineering are designed to be able to mimic the properties and the functions of the extracellular matrix (ECM). In this chapter, the most significant research efforts dedicated to the study and the preparation of biomimetic materials through enzymatic modifications were reviewed. The functionalizations of different polymeric matrices obtained through the catalytic activity of two enzymes (Transglutaminase, TGase and Tyrosinase, TYRase) were discussed. Specifically, the biomimetic applications of TGase and TYRase to confer appropriate biomimetic properties to the biomaterials, such as the possibility to obtain in situ gelling hydrogels and the incorporation of bioactive molecules (growth factors) and cell-binding peptides into the scaffolds, were reviewed. PMID: 21072699 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Chitin, Chitosan and Derivatives for Wound Healing and Tissue Engineering. Adv Biochem Eng Biotechnol. 2010 Nov 12; Authors: Francesko A, Tzanov T Naturally derived polymers possess a number of properties beneficial to wound healing and tissue engineering. The polysaccharides chitin and chitosan appear to be suitable candidates for the preparation of dressing materials and scaffolds for tissue regeneration due to their unique structural, physico-chemical and functional properties. Functionalization of these biopolymers for improvement of properties such as solubility or introduction of active functions and blending with other intrinsically bioactive polymers has attracted considerable attention in recent years. Such modifications would allow going beyond traditional approaches for treatments of dermal injuries. This chapter is a critical review of the advances in chitin and chitosan functionalization for wound-healing and tissue-engineering applications. PMID: 21072697 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Recombinamers: Combining Molecular Complexity with Diverse Bioactivities for Advanced Biomedical and Biotechnological Applications. Adv Biochem Eng Biotechnol. 2010 Nov 12; Authors: Rodríguez-Cabello JC, Pierna M, Fernández-Colino A, García-Arévalo C, Arias FJ The rapid development of polymer science has led to literally thousands of different monomers and an almost endless number of possibilities arising from their combination. The most promising strategy to date has been to consider natural products as macromolecules that provide the best option for obtaining functional materials. Proteins, with their high levels of complexity and functionality, are one of the best examples of this approach. In addition, the development of genetic engineering has permitted the design and highly controlled synthesis of proteinaceous materials with complex and advanced functionalities. Elastin-like recombinamers (ELRs) are presented herein as an example of an extraordinary convergence of different properties that is not found in any other synthetic polymer system. These materials are highly biocompatible, stimuli-responsive, show unusual self-assembly properties, and can incorporate bioactive domains and other functionalities along the polypeptide chain. These attributes are an important factor in the development of biomedical and biotechnological applications such as tissue engineering, drug delivery, purification of recombinant proteins, biosensors or stimuli-responsive surfaces. PMID: 21072696 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Determining the origin of cells in tissue engineered skin substitutes: a pilot study employing in situ hybridization. Pediatr Surg Int. 2010 Nov 12; Authors: Weber AD, Pontiggia L, Biedermann T, Schiestl C, Meuli M, Reichmann E BACKGROUND: Definitive and high-quality coverage of large and, in particular, massive skin defects remains a significant challenge in burn as well as plastic and reconstructive surgery because of donor site shortage. A novel and promising approach to overcome these problems is tissue engineering of skin. Clearly, before eventual clinical application, engineered skin substitutes of human origin must be grafted and then evaluated in animal models. For the various tests to be conducted it is indispensable to be able to identify human cells as such in culture and also to distinguish between graft and recipient tissue after transplantation. Here we describe a tool to identify human cells in vitro and in vivo. METHODS: In situ hybridization allows for the detection and localization of specific DNA or RNA sequences in morphologically preserved cells in culture or tissue sections, respectively. We used digoxigenin-labeled DNA probes corresponding to human-specific Alu repeats in order to identify human keratinocytes grown in culture together with rat cells, and also to label split and full thickness skin grafts of human origin after transplantation on immuno-incompetent rats. RESULTS: Digoxigenin-labeled DNA probing resulted in an intensive nuclear staining of human cells, both in culture and after transplantation onto recipient animals, while recipient animal cells (rat cells) did not stain. CONCLUSION: In situ hybridization using primate-specific Alu probes reliably allows distinguishing between cells of human and non-human origin both in culture as well as in histological sections. This method is an essential tool for those preclinical experiments (performed on non-primate animals) that must be conducted before novel tissue engineered skin substitutes might be introduced into clinical practice. PMID: 21072665 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Use of an insulating mask for controlling anisotropy in multilayer electrospun scaffolds for tissue engineering. J Mater Chem. 2010 Oct 28;20(40):8962-8968 Authors: Garrigues NW, Little D, O'Conor CJ, Guilak F Tissue engineering of various musculoskeletal or cardiovascular tissues requires scaffolds with controllable mechanical anisotropy. However, native tissues also exhibit significant inhomogeneity in their mechanical properties, and the principal axes of anisotropy may vary with site or depth from the tissue surface. Thus, techniques to produce multilayered biomaterial scaffolds with controllable anisotropy may provide improved biomimetic properties for functional tissue replacements. In this study, poly(ε-caprolactone) scaffolds were electrospun onto a collecting electrode that was partially covered by rectangular or square shaped insulating masks. The use of a rectangular mask resulted in aligned scaffolds that were significantly stiffer in tension in the axial direction than the transverse direction at 0 strain (22.9 ± 1.3 MPa axial, 16.1 ± 0.9 MPa transverse), and at 0.1 strain (4.8 ± 0.3 MPa axial, 3.5 ± 0.2 MPa transverse). The unaligned scaffolds, produced using a square mask, did not show this anisotropy, with similar stiffness in the axial and transverse directions at 0 strain (19.7 ± 1.4 MPa axial, 20.8 ± 1.3 MPa transverse) and 0.1 strain (4.4 ± 0.2 MPa axial, 4.6 ± 0.3 MPa, transverse). Aligned scaffolds also induced alignment of adipose stem cells near the expected axis on aligned scaffolds (0.015 ± 0.056 rad), while on the unaligned scaffolds, their orientation showed more variation and was not along the expected axis (1.005 ± 0.225 rad). This method provides a novel means of creating multilayered electrospun scaffolds with controlled anisotropy for each layer, potentially providing a means to mimic the complex mechanical properties of various native tissues. PMID: 21072247 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Characterization of Dental Pulp Stem Cells from Impacted Third Molars Cultured in Low Serum-Containing Medium. Cells Tissues Organs. 2010 Nov 11; Authors: Karbanová J, Soukup T, Suchánek J, Pytlík R, Corbeil D, Mokrý J We isolated and expanded stem cells from dental pulp from extracted third molars using an innovative culture method consisting of low serum-containing medium supplemented with epidermal growth factor and platelet-derived growth factor BB. We evaluated the differentiation potential of these cells when they were growing either adherently or as micromass/spheroid cultures in various media. Undifferentiated and differentiated cells were analyzed by flow cytometry, immunocytochemistry and immunoblotting. The flow cytometry results showed that the dental pulp stem cells (DPSCs) were positive for mesenchymal stromal cell markers, but negative for hematopoietic markers. Immunocytochemical and/or immunoblotting analyses revealed the expression of numerous stem cell markers, including nanog, Sox2, nestin, Musashi-1 and nucleostemin, whereas they were negative for markers associated with differentiated neural, vascular and hepatic cells. Surprisingly, the cells were only slightly positive for α-smooth muscle actin, and a heterogeneous expression of CD146 was observed. When cultured in osteogenic media, they expressed osteonectin, osteopontin and procollagen I, and in micromass cultures, they produced collagen I. DPSCs cultured in TGF-β1/3-supplemented media produced extracellular matrix typical of cartilaginous tissue. The addition of vascular endothelial growth factor to serum-free media resulted in the expression of endothelial markers. Interestingly, when cultured in neurogenic media, DPSCs exhibited de novo or upregulated markers of undifferentiated and differentiated neural cells. Collectively, our data show that DPSCs are self-renewing and able to express markers of bone, cartilage, vascular and neural tissues, suggesting their multipotential capacity. Their easy accessibility makes these cells a suitable source of somatic stem cells for tissue engineering. PMID: 21071916 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | MCP-1, ICAM-1 and VCAM-1 are present in early aneurysmal dilatation in experimental rats. Folia Histochem Cytobiol. 2010 Nov 11;:141-147 Authors: Fan J, Li X, Zhong L, Hao-Tong , Di J, Liu F, Zhao HH, Bai SL Recent studies have suggested that inflammation actively participates in ascending aortic aneurysm formation. The aim of the present study was to evaluate the expression changes of adhesion molecules and MMPs in an experimental model of ascending aortic aneurysm induced by ascending aorta banding in Wistar rats. Twelve rats developed aortic dilation after ascending aorta banding treatment, while nine normal animals underwent surgery without banding were used as controls. Light microscope and scanning electron microscope showed that the wall of the ascending aorta became disorganized as well as infiltration by inflammatory cells in aneurysmal rats. By using immunohistochemical techniques, a significant increase in the immunostaining of MCP-1 was observed in the aneurysmal wall as compared to the normal aortic wall. Under similar experimental conditions, we also found that the immunostaining of ICAM-1 and VCAM-1 was markedly increased in the aneurysmal wall. In addition, gelatin zymographic analysis showed that the expression and acitivities of MMP-2 and MMP-9 were remarkably enhanced in the ascending aorta of ascending aortic aneurysmal rats as compared to normal rats. These results demonstrate that MCP-1, ICAM-1 and VCAM-1 are involved in the pathogenesis of ascending aortic aneurysm and an increase in the immunostaining and activity of MMP-2 and MMP-9 may promote the progression of ascending aortic aneurysm. PMID: 21071353 [PubMed - as supplied by publisher] | | | | | | | | | |  | |  | |  |
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