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| Effect of collagen II coating on mesenchymal stem cell adhesion on chitosan and on reacetylated chitosan fibrous scaffolds.
May 26, 2010 at 8:35 AM
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| | Effect of collagen II coating on mesenchymal stem cell adhesion on chitosan and on reacetylated chitosan fibrous scaffolds. J Mater Sci Mater Med. 2010 May 25; Authors: Ragetly GR, Griffon DJ, Lee HB, Chung YS The biocompatibility and biomimetic properties of chitosan make it attractive for tissue engineering but its use is limited by its cell adhesion properties. Our objectives were to produce and characterize chitosan and reacetylated-chitosan fibrous scaffolds coated with type II collagen and to evaluate the effect of these chemical modifications on mesenchymal stem cell (MSC) adhesion. Chitosan and reacetylated-chitosan scaffolds obtained by a wet spinning method were coated with type II collagen. Scaffolds were characterized prior to seeding with MSCs. The constructs were analyzed for cell binding kinetics, numbers, distribution and viability. Cell attachment and distribution were improved on chitosan coated with type II collagen. MSCs adhered less to reacetylated-chitosan and collagen coating did not improve MSCs attachment on those scaffolds. These findings are promising and encourage the evaluation of the differentiation of MSCs in collagen-coated chitosan scaff! olds. However, the decreased cell adhesion on reacetylated chitosan scaffold seems difficult to overcome and will limit its use for tissue engineering. PMID: 20499139 [PubMed - as supplied by publisher] | | |
| Characterization of tumor progression in engineered tissue using infrared spectroscopic imaging.
May 26, 2010 at 8:35 AM
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| | Characterization of tumor progression in engineered tissue using infrared spectroscopic imaging. Analyst. 2010 May 25; Authors: Kong R, Reddy RK, Bhargava R Engineered tissues can provide models for imaging and disease progression and the use of such models is becoming increasingly prevalent. While structural characterization of these systems is documented, a combination of biochemical and structural knowledge is often helpful. Here, we apply Fourier transform infrared (FT-IR) spectroscopic imaging to examine an engineered tissue model of melanoma. We first characterize the biochemical properties and spectral changes in different layers of growing skin. Second, we introduce malignant melanocytes to simulate tumor formation and growth. Both cellular changes associated with tumor formation and growth can be observed. In particular, chemical changes associated with tumor-stromal interactions are observed during the course of tumor growth and appear to influence a 50-100 mum region. The development of this analytical approach combining engineered tissue with spectroscopy, imaging and computation will allow for quality con! trol and standardization in tissue engineering and novel scientific insight in cancer progression. PMID: 20498913 [PubMed - as supplied by publisher] | | |
| Molecular self-assembly and applications of designer peptide amphiphiles.
May 26, 2010 at 8:35 AM
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| | Molecular self-assembly and applications of designer peptide amphiphiles. Chem Soc Rev. 2010 May 24; Authors: Zhao X, Pan F, Xu H, Yaseen M, Shan H, Hauser CA, Zhang S, Lu JR Short synthetic peptide amphiphiles have recently been explored as effective nanobiomaterials in applications ranging from controlled gene and drug release, skin care, nanofabrication, biomineralization, membrane protein stabilization to 3D cell culture and tissue engineering. This range of applications is heavily linked to their unique nanostructures, remarkable simplicity and biocompatibility. Some peptide amphiphiles also possess antimicrobial activities whilst remaining benign to mammalian cells. These attractive features are inherently related to their selective affinity to different membrane interfaces, high capacity for interfacial adsorption, nanostructuring and spontaneous formation of nano-assemblies. Apart from sizes, the primary sequences of short peptides are very diverse as they can be either biomimetic or de novo designed. Thus, their self-assembling mechanistic processes and the nanostructures also vary enormously. This critical review highlights r! ecent advances in studying peptide amphiphiles, focusing on the formation of different nanostructures and their applications in diverse fields. Many interesting features learned from peptide self-organisation and hierarchical templating will serve as useful guidance for functional materials design and nanobiotechnology (123 references). PMID: 20498896 [PubMed - as supplied by publisher] | | |
| Combination Stem Cell Therapy for the Treatment of Severe Limb Ischemia: Safety and Efficacy Analysis.
May 26, 2010 at 8:35 AM
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| | Combination Stem Cell Therapy for the Treatment of Severe Limb Ischemia: Safety and Efficacy Analysis. Angiology. 2010 May 24; Authors: Lasala GP, Silva JA, Gardner PA, Minguell JJ The infusion of a source of endothelial progenitors (EPCs) to limb ischemia (LB) patients has been used to increase angiogenesis. Because the formation of new blood vessels involves, in addition to EPCs, other cells and angiogenic regulators, we postulate that a combination cell therapy including EPCs and mesenchymal stem cells (a source of pericytes progenitors and angiogenic regulators) may represent a preferential stimuli for the development of blood vessels. In this phase I clinical trial, patients with LI were infused with a cell product consisting of autologous bone marrow-derived mononuclear and mesenchymal stem cells. After 10 +/- 2 months of follow-up, efficacy assessment demonstrated improvements in walking time, ankle brachial pressure, and quality of life. Concomitantly, angiographic and 99mTc-TF perfusion scintigraphy scores confirmed increased perfusion in the treated limbs. These results show that the use of a combination cell therapy is safe, feasi! ble, and appears effective in patients with LI. PMID: 20498146 [PubMed - as supplied by publisher] | | |
| Alternative splicing regulates mouse embryonic stem cell pluripotency and differentiation.
May 26, 2010 at 8:35 AM
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| | Alternative splicing regulates mouse embryonic stem cell pluripotency and differentiation. Proc Natl Acad Sci U S A. 2010 May 24; Authors: Salomonis N, Schlieve CR, Pereira L, Wahlquist C, Colas A, Zambon AC, Vranizan K, Spindler MJ, Pico AR, Cline MS, Clark TA, Williams A, Blume JE, Samal E, Mercola M, Merrill BJ, Conklin BR Two major goals of regenerative medicine are to reproducibly transform adult somatic cells into a pluripotent state and to control their differentiation into specific cell fates. Progress toward these goals would be greatly helped by obtaining a complete picture of the RNA isoforms produced by these cells due to alternative splicing (AS) and alternative promoter selection (APS). To investigate the roles of AS and APS, reciprocal exon-exon junctions were interrogated on a genome-wide scale in differentiating mouse embryonic stem (ES) cells with a prototype Affymetrix microarray. Using a recently released open-source software package named AltAnalyze, we identified 144 genes for 170 putative isoform variants, the majority (67%) of which were predicted to alter protein sequence and domain composition. Verified alternative exons were largely associated with pathways of Wnt signaling and cell-cycle control, and most were conserved between mouse and human. To examine th! e functional impact of AS, we characterized isoforms for two genes. As predicted by AltAnalyze, we found that alternative isoforms of the gene Serca2 were targeted by distinct microRNAs (miRNA-200b, miRNA-214), suggesting a critical role for AS in cardiac development. Analysis of the Wnt transcription factor Tcf3, using selective knockdown of an ES cell-enriched and characterized isoform, revealed several distinct targets for transcriptional repression (Stmn2, Ccnd2, Atf3, Klf4, Nodal, and Jun) as well as distinct differentiation outcomes in ES cells. The findings herein illustrate a critical role for AS in the specification of ES cells with differentiation, and highlight the utility of global functional analyses of AS. PMID: 20498046 [PubMed - as supplied by publisher] | | |
| Optimization of the culturing conditions of human umbilical cord blood-derived endothelial colony-forming cells under xeno-free conditions applying a transcriptomic approach.
May 26, 2010 at 8:35 AM
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| | Optimization of the culturing conditions of human umbilical cord blood-derived endothelial colony-forming cells under xeno-free conditions applying a transcriptomic approach. Genes Cells. 2010 May 20; Authors: Zeisberger SM, Zoller S, Riegel M, Chen S, Krenning G, Harmsen MC, Sachinidis A, Zisch AH Establishment of fetal bovine serum (FBS)-free cell culture conditions is essential for transplantation therapies. Blood-derived endothelial colony-forming cells (ECFCs) are potential candidates for regenerative medicine applications. ECFCs were isolated from term umbilical cord blood units and characterized by flow cytometry, capillary formation and responsiveness to cytokines. ECFCs were expanded under standard, FBS-containing endothelial medium, or transferred to chemically defined endothelial media without FBS. Microarray expression profiling was applied to compare the transcriptome profiles in FBS-containing versus FBS-free culture. ECFC outgrowth in standard medium was successful in 92% of cord blood units. The karyotype of expanded ECFCs remained normal. Without FBS, ECFC initiation and expansion failed. Modest proliferation, changes in cell morphology and organization and cell death have been observed after passaging. Gene ontology analysis revealed a broa! d down-regulation of genes involved in cell cycle progression and up-regulation of genes involved in stress response and apoptosis. Interestingly, genes participating in lipid biosynthesis were markedly up-regulated. Detection of several endothelial cell-specific marker genes showed the maintenance of the endothelial cell characteristics during serum-free culture. Although ECFCs maintain their endothelial characteristics during serum-free culturing, they could not be expanded. Additional supply of FBS-free media with lipid concentrates might increase the ECFC survival. PMID: 20497237 [PubMed - as supplied by publisher] | | |
| Nanotechnologies in regenerative medicine.
May 26, 2010 at 8:35 AM
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| | Nanotechnologies in regenerative medicine. Minim Invasive Ther Allied Technol. 2010 Jun;19(3):144-56 Authors: Kubinová S, Syková E Abstract Nanotechnology offers promising perspectives in biomedical research as well as in clinical practice. To cover some of the latest nanotechnology trends in regenerative medicine, this review will focus on the use of nanomaterials for tissue engineering and cell therapy. Nanofibrous materials that mimic the native extracellular matrix and promote the adhesion of various cells are being developed as tissue-engineered scaffolds for the skin, bone, vasculature, heart, cornea, nervous system, and other tissues. A range of novel materials has been developed to enhance the bioactive or therapeutic properties of these nanofibrous scaffolds via surface modifications, including the immobilization of functional cell-adhesive ligands and bioactive molecules such as drugs, enzymes and cytokines. As a new approach, nanofibers prepared by using industrial scale needleless technology have been recently introduced, and their use as scaffolds to treat spinal cord injury or a! s cell carriers for the regeneration of the injured cornea is the subject of much current study. Cell therapy is a modern approach of regenerative medicine for the treatment of various diseases or injuries. To follow the migration and fate of transplanted cells, superparamagnetic iron oxide nanoparticles have been developed for cell labeling and non-invasive MRI monitoring of cells in the living organism, with successful applications in, e.g, the central nervous system, heart, liver and kidney and also in pancreatic islet and stem cell transplantation. PMID: 20497067 [PubMed - in process] | | |
| Bone morphogenetic protein-2 delivered by hyaluronan-based hydrogel induces massive bone formation and healing of cranial defects in minipigs.
May 26, 2010 at 8:35 AM
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| | Bone morphogenetic protein-2 delivered by hyaluronan-based hydrogel induces massive bone formation and healing of cranial defects in minipigs. Plast Reconstr Surg. 2010 May;125(5):1383-92 Authors: Docherty-Skogh AC, Bergman K, Waern MJ, Ekman S, Hultenby K, Ossipov D, Hilborn J, Bowden T, Engstrand T BACKGROUND: Reconstruction of large craniofacial bone defects is a challenge using bone transplants or alloplastic materials. The use of bone morphogenetic protein (BMP)-2 together with a suitable carrier is an attractive option that may facilitate new bone formation. The authors have developed a hydrogel that is formed in situ by the cross-linking of multifunctional hyaluronic acid and polyvinyl alcohol derivatives mixed with hydroxyapatite nanoparticles, in the presence of BMP-2. The aim of this study was to evaluate the suitability of the hydrogel as a carrier for BMP-2 in repairing critical size cranial defects in a minipig model. METHODS: Cranial defects (2 x 4 cm) were created in 14 minipigs. The experimental groups were as follows: group 1, craniotomy and application of 5 ml of hydrogel with 1.25 mg of BMP-2 (n = 6); group 2, craniotomy and application of 5 ml of hydrogel without BMP-2 (n = 6); and group 3, craniotomy with no further treatment (n = 2). RESU! LTS: After 3 months, computed tomographic and histologic examinations were performed. There was spontaneous ossification in the untreated group, but the healing was incomplete. The hydrogel alone demonstrated no further effects. The addition of 1.25 mg of BMP-2 to the hydrogel induced a greater than 100 percent increase in bone volume (p = 0.003) and complete healing of the defects. Histologic examination revealed compact lamellar bone in the BMP group without intertrabecular fibrous tissue, as was seen in the other groups. The hydrogel was resorbed completely within 3 months and, importantly, caused no inflammatory reaction. CONCLUSION: The injectable hydrogel may be favorable as a BMP-2 carrier for bone reconstruction. PMID: 20440158 [PubMed - indexed for MEDLINE] | | |
| Human periosteum-derived cells combined with superporous hydroxyapatite blocks used as an osteogenic bone substitute for periodontal regenerative therapy: an animal implantation study using nude mice.
May 26, 2010 at 8:35 AM
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| | Human periosteum-derived cells combined with superporous hydroxyapatite blocks used as an osteogenic bone substitute for periodontal regenerative therapy: an animal implantation study using nude mice. J Periodontol. 2010 Mar;81(3):420-7 Authors: Kawase T, Okuda K, Kogami H, Nakayama H, Nagata M, Sato T, Wolff LF, Yoshie H BACKGROUND: A superporous (85%) hydroxyapatite (HA) block was recently developed to improve osteoconductivity, but it was often not clinically successful when used to treat periodontal osseous defects. The primary purpose of this study is to develop a clinically applicable tissue-engineered bone substitute using this HA block and human alveolar periosteum-derived cells. METHODS: Commercially available superporous HA blocks were acid treated and subjected to a three-dimensional (3D) culture for periosteal cell cultivation. Cells in the pore regions of the treated HA block were observed on the fracture surface by scanning electron microscopy. After osteogenic induction, the cell-HA complexes were implanted subcutaneously in nude mice. Osteoid formation was histologically evaluated. RESULTS: Acid treatment enlarged the interconnections among pores, resulting in the deep penetration of periosteal cells. Under these conditions, cells were maintained for >2 weeks wit! hout appreciable cell death in the deep pore regions of the HA block. The cell-HA complexes that received in vitro osteogenic induction formed osteoids in pore regions of the treated HA blocks in vivo. In contrast, most pore regions in the non-pretreated, cell-free HA blocks that were evaluated in vivo remained cell free. CONCLUSIONS: Our findings suggest that an acid-treated HA block could function as a better scaffold for the 3D high-density culture of human periosteal cells in vitro, and this cell-HA complex had significant osteogenic potential at the site of implantation in vivo. Compared with the cell-free HA block, our cell-HA complex using periosteal cells, which are the most accessible for clinical periodontists, showed promising results as a bone substitute in periodontal regenerative therapy. PMID: 20192869 [PubMed - indexed for MEDLINE] | | |
| Conference Scene: NanoBiotech Montreux 2009.
May 26, 2010 at 8:35 AM
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| | Conference Scene: NanoBiotech Montreux 2009. Nanomedicine (Lond). 2010 Feb;5(2):177-9 Authors: Hollis V, Morgan H PMID: 20148630 [PubMed - indexed for MEDLINE] | | |
| Slow-freezing cryopreservation of neural stem cell spheres with different diameters.
May 26, 2010 at 8:35 AM
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| | Slow-freezing cryopreservation of neural stem cell spheres with different diameters. Cryobiology. 2010 Apr;60(2):184-91 Authors: Ma XH, Shi Y, Hou Y, Liu Y, Zhang L, Fan WX, Ge D, Liu TQ, Cui ZF Neural stem cells (NSCs) are of great value for clinical application and scientific research. The development of efficient cryopreservation protocols could significantly facilitate the storage and transportation for clinic applications. The objective of the present study is to improve the survival rate and viability of NSCs. Neural stem cells with three states of single-cell suspension, NSC spheres with diameters of 30-50 microm and 80-100 microm, were cryopreserved by slow-freezing method with the cryoprotective agent (CPA) of dimethyl sulfoxide (Me(2)SO), respectively. Then the post-thawing NSCs were tested for the survival rate and the differentiation ability. As a result, NSC spheres with diameter of 80-100 microm and Me(2)SO concentration of 8% achieve the survival rate of 82.9%, and the NSCs still sustain the multi-differentiation potentiality. These results indicated that both the subtle interaction among NSCs and sphere diameters may affect the survival ra! te together. PMID: 19895801 [PubMed - indexed for MEDLINE] | | | | 
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