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| Exploring cellular adhesion and differentiation in a micro-/nano-hybrid polymer scaffold.
March 3, 2010 at 6:08 AM
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| | Exploring cellular adhesion and differentiation in a micro-/nano-hybrid polymer scaffold. Biotechnol Prog. 2010 Jan 29; Authors: Cheng K, Kisaalita WS Polymer scaffolds play an important role in three dimensional (3-D) cell culture and tissue engineering. To best mimic the archiecture of natural extracellular matrix (ECM), a nano-fibrous and micro-porous combined (NFMP) scaffold was fabricated by combining phase separation and particulate leaching techniques. The NFMP scaffold possesses architectural features at two levels, including the micro-scale pores and nano-scale fibers. To evaluate the advantages of micro/nano combination, control scaffolds with only micro-pores or nano-fibers were fabricated. Cell grown in NFMP and control scaffolds were characterized with respect to morphology, proliferation rate, diffentiation and adhesion. The NFMP scaffold combined the advantages of micro- and nano-scale structures. The NFMP scaffold nano-fibers promoted neural differentiation and induced "3-D matrix adhesion", while the NFMP scaffold micro-pores facilitated cell infiltration. This study represents a systematic comp! arison of cellular activities on micro-only, nano-only and micro/nano combined scaffolds, and demonstrates the unique advantages of the later. (c) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010. PMID: 20196160 [PubMed - as supplied by publisher] | | |
| A rotating bed system bioreactor enables cultivation of primary osteoblasts on well-characterized sponceram(R) regarding structural and flow properties.
March 3, 2010 at 6:08 AM
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| | A rotating bed system bioreactor enables cultivation of primary osteoblasts on well-characterized sponceram(R) regarding structural and flow properties. Biotechnol Prog. 2010 Jan 29; Authors: Suck K, Roeker S, Diederichs S, Anton F, Sanz-Herrera JA, Ochoa I, Doblare M, Scheper T, van Griensven M, Kasper C The development of bone tissue engineering depends on the availability of suitable biomaterials, a well-defined and controlled bioreactor system, and on the use of adequate cells. The biomaterial must fulfill chemical, biological, and mechanical requirements. Besides biocompatibility, the structural and flow characteristics of the biomaterial are of utmost importance for a successful dynamic cultivation of osteoblasts, since fluid percolation within the microstructure must be assured to supply to cells nutrients and waste removal. Therefore, the biomaterial must consist of a three-dimensional structure, exhibit high porosity and present an interconnected porous network. Sponceram(R), a ZrO(2) based porous ceramic, is characterized in the presented work with regard to its microstructural design. Intrinsic permeability is obtained through a standard Darcy's experiment, while Young's modulus is derived from a two plates stress-strain test in the linear range. Further! more, the material is applied for the dynamic cultivation of primary osteoblasts in a newly developed rotating bed bioreactor. (c) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010. PMID: 20196152 [PubMed - as supplied by publisher] | | |
| Effect of psoralen on bone formation.
March 3, 2010 at 6:08 AM
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| | Effect of psoralen on bone formation. J Orthop Res. 2010 Mar 1; Authors: Wong RW, Rabie AB To compare the amount of new bone and bone cells produced by psoralen in collagen matrix to that produced by collagen matrix in vivo. Eighteen bone defects, 5 mm by 10 mm were created in the parietal bone of nine New Zealand White rabbits. Six defects were grafted with psoralen mixed with collagen matrix. Six defects were grafted with collagen matrix alone (negative control-collagen) and six were left empty (negative control-empty). Animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Quantitative analysis of new bone formation and bone cells were made on 100 sections (50 sections for each group) using image analysis. A total of 454% more new bone was present in defects grafted with psoralen in collagen matrix than those grafted with collagen matrix. No bone was formed in the negative control-empty group. The amount of bone forming osteoblasts was also significantly greater in the psoralen group than the negative c! ontrol-collagen group. Psoralen in collagen matrix has the effect of increasing new bone formation locally in vivo. Psoralen in collagen matrix can be developed as a bone graft material. (c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. PMID: 20196083 [PubMed - as supplied by publisher] | | |
| Injectable Biodegradable Hydrogels.
March 3, 2010 at 6:08 AM
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| | Injectable Biodegradable Hydrogels. Macromol Biosci. 2010 Mar 1; Authors: Nguyen MK, Lee DS Injectable biodegradable copolymer hydrogels, which exhibit a sol-gel phase transition in response to external stimuli, such as temperature changes or both pH and temperature (pH/temperature) alterations, have found a number of uses in biomedical and pharmaceutical applications, such as drug delivery, cell growth, and tissue engineering. These hydrogels can be used in simple pharmaceutical formulations that can be prepared by mixing the hydrogel with drugs, proteins, or cells. Such formulations are administered in a straightforward manner, through site-specific control of release behavior, and the hydrogels are compatible with biological systems. This review will provide a summary of recent progress in biodegradable temperature-sensitive polymers including polyesters, polyphosphazenes, polypeptides, and chitosan, and pH/temperature-sensitive polymers such as sulfamethazine-, poly(beta-amino ester)-, poly(amino urethane)-, and poly(amidoamine)-based polymers. The a! dvantages of pH/temperature-sensitive polymers over simple temperature-sensitive polymers are also discussed. A perspective on the future of injectable biodegradable hydrogels is offered. PMID: 20196065 [PubMed - as supplied by publisher] | | |
| Nano iron oxide-hydroxyapatite composite ceramics with enhanced radiopacity.
March 3, 2010 at 6:08 AM
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| | Nano iron oxide-hydroxyapatite composite ceramics with enhanced radiopacity. J Mater Sci Mater Med. 2010 Feb 27; Authors: Ajeesh M, Francis BF, Annie J, Harikrishna Varma PR Hydroxyapatite has been widely used for a variety of bone filling and augmentation applications. But the poorly resolved X-ray image of certain hydroxyapatite (HA) based implants such as porous blocks and self setting HA cements is a radiological problem to surgeons for monitoring of the implant and early diagnosis complications. In the present work the practical difficulty related to the reduced X-ray opacity was overcome by exploiting the contrast enhancement property of iron oxide nano particles. Sintered nano iron oxide-HA composite ceramics were prepared from powders produced through a co-precipitation route. The phase purity and bioactivity of the composites were analyzed as a function of percentage iron oxide in the composite. The X-ray attenuation of dense and porous composites was compared with pure HA using a C-arm X-ray imaging system and micro computed tomography. In all the prepared composites, HA retains its phase identity and high X-ray opacity as o! btained for a composition containing 40 wt% iron oxide. The increased cell viability and cell adhesion nature depicted by the prepared composite offers considerable interest for the material in bone tissue engineering applications. PMID: 20195889 [PubMed - as supplied by publisher] | | |
| Immune physiology in tissue regeneration and aging, tumor growth, and regenerative medicine.
March 3, 2010 at 6:08 AM
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| | Immune physiology in tissue regeneration and aging, tumor growth, and regenerative medicine. Aging (Albany NY). 2009 Feb;1(2):157-81 Authors: Bukovsky A, Caudle MR, Carson RJ, Gaytán F, Huleihel M, Kruse A, Schatten H, Telleria CM The immune system plays an important role in immunity (immune surveillance), but also in the regulation of tissue homeostasis (immune physiology). Lessons from the female reproductive tract indicate that immune system related cells, such as intraepithelial T cells and monocyte-derived cells (MDC) in stratified epithelium, interact amongst themselves and degenerate whereas epithelial cells proliferate and differentiate. In adult ovaries, MDC and T cells are present during oocyte renewal from ovarian stem cells. Activated MDC are also associated with follicular development and atresia, and corpus luteum differentiation. Corpus luteum demise resembles rejection of a graft since it is attended by a massive influx of MDC and T cells resulting in parenchymal and vascular regression. Vascular pericytes play important roles in immune physiology, and their activities (including secretion of the Thy-1 differentiation protein) can be regulated by vascular autonomic innervati! on. In tumors, MDC regulate proliferation of neoplastic cells and angiogenesis. Tumor infiltrating T cells die among malignant cells. Alterations of immune physiology can result in pathology, such as autoimmune, metabolic, and degenerative diseases, but also in infertility and intrauterine growth retardation, fetal morbidity and mortality. Animal experiments indicate that modification of tissue differentiation (retardation or acceleration) during immune adaptation can cause malfunction (persistent immaturity or premature aging) of such tissue during adulthood. Thus successful stem cell therapy will depend on immune physiology in targeted tissues. From this point of view, regenerative medicine is more likely to be successful in acute rather than chronic tissue disorders. PMID: 20195382 [PubMed - in process] | | |
| Protective effect of human amniotic fluid stem cells in an immunodeficient mouse model of acute tubular necrosis.
March 3, 2010 at 6:08 AM
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| | Protective effect of human amniotic fluid stem cells in an immunodeficient mouse model of acute tubular necrosis. PLoS One. 2010;5(2):e9357 Authors: Perin L, Sedrakyan S, Giuliani S, Da Sacco S, Carraro G, Shiri L, Lemley KV, Rosol M, Wu S, Atala A, Warburton D, De Filippo RE Acute Tubular Necrosis (ATN) causes severe damage to the kidney epithelial tubular cells and is often associated with severe renal dysfunction. Stem-cell based therapies may provide alternative approaches to treating of ATN. We have previously shown that clonal c-kit(pos) stem cells, derived from human amniotic fluid (hAFSC) can be induced to a renal fate in an ex-vivo system. Herein, we show for the first time the successful therapeutic application of hAFSC in a mouse model with glycerol-induced rhabdomyolysis and ATN. When injected into the damaged kidney, luciferase-labeled hAFSC can be tracked using bioluminescence. Moreover, we show that hAFSC provide a protective effect, ameliorating ATN in the acute injury phase as reflected by decreased creatinine and BUN blood levels and by a decrease in the number of damaged tubules and apoptosis therein, as well as by promoting proliferation of tubular epithelial cells. We show significant immunomodulatory effects of hA! FSC, over the course of ATN. We therefore speculate that AFSC could represent a novel source of stem cells that may function to modulate the kidney immune milieu in renal failure caused by ATN. PMID: 20195358 [PubMed - in process] | | |
| Synergistic effects of electrospun PLLA fiber dimension and pattern on neonatal mouse cerebellum C17.2 stem cells.
March 3, 2010 at 6:08 AM
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| | Synergistic effects of electrospun PLLA fiber dimension and pattern on neonatal mouse cerebellum C17.2 stem cells. Acta Biomater. 2010 Feb 26; Authors: He L, Liao S, Quan D, Ma K, Chan C, Ramakrishna S Topographical features, including fiber dimension and pattern, are important aspect in developing a fibrous scaffold for tissue engineering. In this study, poly(L-lactide) (PLLA) aligned fibers with the diameter of 307 +/- 47 nm, 500 +/- 53 nm, 679 +/- 72, 917 +/- 84 nm and random fibers with the diameter of 327 +/- 40 nm, 545 +/- 54 nm, 746 +/- 82 nm, 1150 +/- 109 nm were obtained by optimizing electrospinning parameters. We cultured neonatal mouse cerebellum C17.2 cells on the PLLA fibers and the neural stem cells (NSCs) exhibited significantly different growth and differentiation with the fiber dimension and pattern. On aligned fibers, cell viability and proliferation was best on 500 nm fibers, and reduced on smaller or larger fibers. However, on random fibers, cell viability and proliferation was best with the smallest (350 nm) and largest (1150 nm) diameter fibers. Polarized and elongated cells were orientated along the fiber direction on the aligned fibers w! ith focal contacts bridging the cell body and aligned fibers. Cells of spindle and polygonal morphologies were randomly distributed on the random fibers with no focal contacts observed. Moreover, longer neurites were obtained on the aligned fibers than random fibers within the same diameter range. Therefore, the surface topographic morphologies of fibrous scaffolds, including fiber pattern, dimension and mesh size played roles in regulating the viability, proliferation and neurite outgrowth of neural stem cells. Nevertheless, our results indicated that 500-nm aligned fiber is the most promising for fine-tuning the design for a nerve scaffold. PMID: 20193781 [PubMed - as supplied by publisher] | | |
| Injectable cardiac tissue engineering for the treatment of myocardial infarction.
March 3, 2010 at 6:08 AM
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| | Injectable cardiac tissue engineering for the treatment of myocardial infarction. J Cell Mol Med. 2010 Feb 27; Authors: Wang H, Zhou J, Liu Z, Wang C Heart disease is a leading cause of morbidity and mortality worldwide. Myocardial infarction leads to permanent loss of cardiac tissue and ultimately heart failure. However, current therapies could only stall the progression of the disease. Thus new therapies are needed to regenerate damaged hearts to overcome poor prognosis of patients with heart failure. The shortage of heart donors is also a factor for innovating new therapies. Although the cardiac performance by cell-based therapy has improved, unsatisfactory cell retention and transplant survival still plague this technique. Since biomaterials can improve the cell retention, survival, and differentiation, cardiac tissue engineering is now being explored as an approach to support cell-based therapies and enhance their efficacy for cardiac disease. In the last decade, cardiac tissue engineering has made considerable progress. Among different kinds of approaches in the cardiac tissue engineering, the approach of! injectable cardiac tissue engineering is more minimally invasive than that of in vitro-engineered tissue or epicardial patch implantation. It is therefore clinically appealing. In this review, we strive to describe the major progress in the flied of injectable cardiac tissue engineering, including seeding cell sources, biomaterials, and novel findings in preclinical studies and clinical applications. The remaining problems will also be discussed. PMID: 20193036 [PubMed - as supplied by publisher] | | |
| In Situ Collagen Polymerization of Layered Cell-Seeded Electrospun Scaffolds for Bone Tissue Engineering Applications.
March 3, 2010 at 6:08 AM
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| | In Situ Collagen Polymerization of Layered Cell-Seeded Electrospun Scaffolds for Bone Tissue Engineering Applications. Tissue Eng Part C Methods. 2010 Mar 2; Authors: McCullen SD, Miller PR, Gittard SD, Gorga RE, Pourdeyhimi B, Narayan RJ, Loboa EG Electrospun scaffolds have been studied extensively for their potential use in bone tissue engineering applications. However, inherent issues with the electrospinning approach limit the thickness of these scaffolds and constrain their use for repair of critical-sized bone defects. One method to increase overall scaffold thickness is to bond multiple electrospun scaffolds together with a biocompatible gel. The objective of this study was to determine whether multiple human adipose-derived stem cell (hASC)-seeded electrospun, nanofibrous scaffolds could be layered via in situ collagen assembly and whether the addition of laser-ablated micron-sized pores within the electrospun scaffold layers was beneficial to the bonding process. Pores were created by a laser ablation technique. We hypothesized that the addition of micron-sized pores within the electrospun scaffolds would encourage collagen integration between scaffold layers, and promote osteogenic differentiation ! of hASCs seeded within the layered electrospun scaffolds. To evaluate the benefit of assembled scaffolds with and without engineered pores, hASCs were seeded on individual electrospun scaffolds, hASC-seeded scaffolds were bonded with type I collagen, and the assembled approximately 3-mm-thick constructs were cultured for 3 weeks to examine their potential as bone tissue engineering scaffolds. Assembled electrospun scaffolds/collagen gel constructs using electrospun scaffolds with pores resulted in enhanced hASC viability, proliferation, and mineralization of the scaffolds after 3 weeks in vitro compared to constructs using electrospun scaffolds without pores. Scanning electron microscopy and histological examination revealed that the assembled constructs that included laser-ablated electrospun scaffolds were able to maintain a contracted structure and were not delaminated, unlike assembled constructs containing nonablated electrospun scaffolds. This is the first study to sh! ow that the introduction of engineered pores in electrospun sc! affolds assists with multilayered scaffold integration, resulting in thick constructs potentially suitable for use as scaffolds for bone tissue engineering or repair of critical bone defects. PMID: 20192901 [PubMed - as supplied by publisher] | | |
| Late-term results of tissue-engineered vascular grafts in humans.
March 3, 2010 at 6:08 AM
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| | Late-term results of tissue-engineered vascular grafts in humans. J Thorac Cardiovasc Surg. 2010 Feb;139(2):431-6, 436.e1-2 Authors: Hibino N, McGillicuddy E, Matsumura G, Ichihara Y, Naito Y, Breuer C, Shinoka T OBJECTIVE: The development of a tissue-engineered vascular graft with the ability to grow and remodel holds promise for advancing cardiac surgery. In 2001, we began a human trial evaluating these grafts in patients with single ventricle physiology. We report the late clinical and radiologic surveillance of a patient cohort that underwent implantation of tissue-engineered vascular grafts as extracardiac cavopulmonary conduits. METHODS: Autologous bone marrow was obtained and the mononuclear cell component was collected. Mononuclear cells were seeded onto a biodegradable scaffold composed of polyglycolic acid and epsilon-caprolactone/L-lactide and implanted as extracardiac cavopulmonary conduits in patients with single ventricle physiology. Patients were followed up by postoperative clinic visits and by telephone. Additionally, ultrasonography, angiography, computed tomography, and magnetic resonance imaging were used for postoperative graft surveillance. RESULTS: T! wenty-five grafts were implanted (median patient age, 5.5 years). There was no graft-related mortality (mean follow-up, 5.8 years). There was no evidence of aneurysm formation, graft rupture, graft infection, or ectopic calcification. One patient had a partial mural thrombosis that was successfully treated with warfarin. Four patients had graft stenosis and underwent successful percutaneous angioplasty. CONCLUSION: Tissue-engineered vascular grafts can be used as conduits in patients with single ventricle physiology. Graft stenosis is the primary mode of graft failure. Further follow-up and investigation for the mechanism of stenosis are warranted. PMID: 20106404 [PubMed - indexed for MEDLINE] | | |
| Induced pluripotent stem cells, new tools for drug discovery and new hope for stem cell therapies.
March 3, 2010 at 6:08 AM
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| | Induced pluripotent stem cells, new tools for drug discovery and new hope for stem cell therapies. Curr Mol Pharmacol. 2009 Jan;2(1):15-8 Authors: Shi Y Somatic cell nuclear transfer or therapeutic cloning has provided great hope for stem cell-based therapies. However, therapeutic cloning has been experiencing both ethical and technical difficulties. Recent breakthrough studies using a combination of four factors to reprogram human somatic cells into pluripotent stem cells without using embryos or eggs have led to an important revolution in stem cell research. Comparative analysis of human induced pluripotent stem cells and human embryonic stem cells using assays for morphology, cell surface marker expression, gene expression profiling, epigenetic status, and differentiation potential have revealed a remarkable degree of similarity between these two pluripotent stem cell types. This mini-review summarizes these ground-breaking studies. These advances in reprogramming will enable the creation of patient-specific stem cell lines to study various disease mechanisms. The cellular models created will provide valuable t! ools for drug discovery. Furthermore, this reprogramming system provides great potential to design customized patient-specific stem cell therapies with economic feasibility. PMID: 20021441 [PubMed - indexed for MEDLINE] | | |
| Both epithelial cells and mesenchymal stem cell-derived chondrocytes contribute to the survival of tissue-engineered airway transplants in pigs.
March 3, 2010 at 6:08 AM
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| | Both epithelial cells and mesenchymal stem cell-derived chondrocytes contribute to the survival of tissue-engineered airway transplants in pigs. J Thorac Cardiovasc Surg. 2010 Feb;139(2):437-43 Authors: Go T, Jungebluth P, Baiguero S, Asnaghi A, Martorell J, Ostertag H, Mantero S, Birchall M, Bader A, Macchiarini P OBJECTIVE: We sought to determine the relative contributions of epithelial cells and mesenchymal stem cell-derived chondrocytes to the survival of tissue-engineered airway transplants in pigs. METHODS: Nonimmunogenic tracheal matrices were obtained by using a detergent-enzymatic method. Major histocompatibility complex-unmatched animals (weighing 65 +/- 4 kg) were divided into 4 groups (each n = 5), and 6 cm of their tracheas were orthotopically replaced with decellularized matrix only (group I), decellularized matrix with autologous mesenchymal stem cell-derived chondrocytes externally (group II), decellularized matrix with autologous epithelial cells internally (group III), or decellularized matrix with both cell types (group IV). Autologous cells were recovered, cultured, and expanded. Mesenchymal stem cells were differentiated into chondrocytes by using growth factors. Both cell types were seeded simultaneously with a dual-chamber bioreactor. Animals were not ! immunosuppressed during the entire study. Biopsy specimens and blood samples were taken from recipients continuously, and animals were observed for a maximum of 60 days. RESULTS: Matrices were completely covered with both cell types within 72 hours. Survival of the pigs was significantly affected by group (P < .05; group I, 11 +/- 2 days; group II, 29 +/- 4 days; group III, 34 +/- 4 days; and group IV, 60 +/- 1 days). Cause of death was a combination of airway obstruction and infection (group I), mainly infection (group II), or primarily stenosis (group III). However, pigs in group IV were alive, with no signs of airway collapse or ischemia and healthy epithelium. There were no clinical, immunologic, or histologic signs of rejection despite the lack of immunosuppression. CONCLUSIONS: We confirm the clinical potential of autologous cell- and tissue-engineered tracheal grafts, and suggest that the seeding of both epithelial and mesenchymal stem cell-derived chondrocytes is! necessary for optimal graft survival. PMID: 19995663 [PubMed - indexed for MEDLINE] | | |
| Foamed surfactant solution as a template for self-setting injectable hydroxyapatite scaffolds for bone regeneration.
March 3, 2010 at 6:08 AM
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| | Foamed surfactant solution as a template for self-setting injectable hydroxyapatite scaffolds for bone regeneration. Acta Biomater. 2010 Mar;6(3):876-85 Authors: Montufar EB, Traykova T, Gil C, Harr I, Almirall A, Aguirre A, Engel E, Planell JA, Ginebra MP The application of minimally invasive surgical techniques in the field of orthopaedic surgery has created a growing need for new injectable synthetic materials that can be used for bone grafting. In this work a novel fully synthetic injectable calcium phosphate foam was developed by mixing alpha-tricalcium phosphate (alpha-TCP) powder with a foamed polysorbate 80 solution. Polysorbate 80 is a non-ionic surfactant approved for parenteral applications. The foam was able to retain the porous structure after injection provided that the foamed paste was injected shortly after mixing (typically 2.5 min), and set through the hydrolysis of alpha-TCP to a calcium-deficient hydroxyapatite, thus producing a hydroxyapatite solid foam in situ. The effect of different processing parameters on the porosity, microstructure, injectability and mechanical properties of the hydroxyapatite foams was analysed, and the ability of the pre-set foam to support osteoblastic-like cell prolif! eration and differentiation was assessed. Interestingly, the concentration of surfactant needed to obtain the foams was lower than that considered safe in drug formulations for parenteral administration. The possibility of combining bioactivity, injectability, macroporosity and self-setting ability in a single fully synthetic material represents a step forward in the design of new materials for bone regeneration compatible with minimally invasive surgical techniques. PMID: 19835998 [PubMed - indexed for MEDLINE] | | |
| In vitro myogenic and adipogenic differentiation model of genetically engineered bovine embryonic fibroblast cell lines.
March 3, 2010 at 6:08 AM
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| | In vitro myogenic and adipogenic differentiation model of genetically engineered bovine embryonic fibroblast cell lines. Biotechnol Lett. 2010 Feb;32(2):195-202 Authors: Yin J, Jin X, Beck S, Kang DH, Hong Z, Li Z, Jin Y, Zhang Q, Choi YJ, Kim SC, Kim H Our current understanding of muscle and adipose tissue development has been largely restricted to the study of murine myogenic and adipogenic cell lines, since attempts to establish these cell lines from other species have met with only limited success. Here we report that a spontaneously immortalized bovine embryonic fibroblast cell line (BEFS) undergoes differentiation into adipogenic or myogenic lineages when ectopically transduced with PPARgamma2 (an adipogenic lineage determinant) or MyoD (a myogenic lineage determinant) and grown in adipogenic and myogenic differentiation culture media (ADCM and MDCM, respectively). We also found that PPARgamma2-overexpressing BEFS cells (BEFS-PPARgamma2) grown in ADCM with or without the PPARgamma2 ligand, troglitazone, preferentially differentiate into adipogenic cells in the presence of ectopic MyoD expression. Ectopic expression of PPARgamma2 in the inducible MyoD-overepxressing BEFS cells (BEFS-TetOn-MyoD) completely su! ppresses myogenic differentiation and leads to a significant increase in adipogenic differentiation, suggesting that the adipogenic differentiation program might be dominant. Therefore, BEFS, BEFS-PPARgamma2, and BEFS-TetOn-MyoD would be a valuable biological model for understanding a fundamental principle underlying myogenic and adipogenic development, and for isolating various genetic and chemical factors that enable muscle and adipocyte differentiation. PMID: 19834648 [PubMed - indexed for MEDLINE] | | |
| Role of hypoxia in stem cell development and functioning.
March 3, 2010 at 6:08 AM
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| | Role of hypoxia in stem cell development and functioning. Fiziol Zh. 2009;55(4):116-30 Authors: Nikolsky I, Serebrovska TV The response of stem cells (SC) to hypoxia is one of the main mechanisms of an organism's adaptation to changing terms of external and internal environment. This review describes the role of hypoxia in functioning of various stem cell, types--embryonic, hematopoietic, nmesenchvmal and neural, paying special attention to the very limited data concerning intermittent hypoxia (IH) effects. All stem cells and their precursors exist in microenvironment named stem cell niches. The most crucial factor for their normal functioning is hypoxia. which contributes to maintaining the SC in quiescent state with necessary rate of self-renewal. The key element qf these mechanisms is a complex of hypoxia-inducible transcription factors. An additional exogenous hypoxic impact leads to activation of SC system. Very scant information on IH effects on SC that was obtained generally in cell culture models, reveals that intermittent hypoxia at certain duration and intensity is a more po! tent trigger of transcription activation than constant hypoxia. In the future a method of IH training/treatment could be effectively used for correction of physiological changes and pathological disorders in art organism. PMID: 19827638 [PubMed - indexed for MEDLINE] | | |
| Post-culture treatment protocols for PLGA membrane scaffolds.
March 3, 2010 at 6:08 AM
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| | Post-culture treatment protocols for PLGA membrane scaffolds. Biotechnol Lett. 2010 Feb;32(2):215-22 Authors: Ellis MJ, Forsey R, Chaudhuri JB The interactions of post-culture treatments reagents used for fixing, lysing and cell quantification on poly(lactide-co-glycolide) (PLGA) flat sheet membrane scaffolds are presented. Lysing with Alkaline buffer solution/Triton X-100/MilliQ water (ATM) and fixing with 10% Neutral Buffered Formalin (10% NBF) had no affect on membrane structure while fixing with 95% ethanol caused smoothing of the surface, shrinkage and a reduction in surface area of 55, 48 and 33, for 100:0, 75:25 and 50:50 (PLA:PGA), respectively. PicoGreen assay was selected for cell (560pZIPv.neo) quantification since the background noise would not affect readings for cell numbers over 3,000 cells/cm(2), while the background reading was too high for MTT and Methylene Blue (MB). MB at 0.5% (w/v) was, however, deemed suitable for visualising cell morphology on the membranes. Furthermore ATM buffer was suitable for the PicoGreen assay, which allows the same samples to be used for quantification of a! lkaline phosphatase activity. PMID: 19821075 [PubMed - indexed for MEDLINE] | | |
| Enhanced proliferation capacity of porcine tenocytes in low O2 tension culture.
March 3, 2010 at 6:08 AM
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| | Enhanced proliferation capacity of porcine tenocytes in low O2 tension culture. Biotechnol Lett. 2010 Feb;32(2):181-7 Authors: Zhang Y, Wang B, Zhang WJ, Zhou G, Cao Y, Liu W Tenocytes reside in relatively avascular tissue and are difficult to expand due to phenotype drift and functional loss. Thus low O(2) tension culture was employed to enhance the expansion capability. The results demonstrated that low O(2) tension (2% O(2)) culture could significantly enhance the expansion of newborn pig tenocytes with 275-473% greater cell yield per cell passage that that of regular O(2) cultured (21% O(2)) cells. Importantly, low O(2) culture did not change the gene expression of functional molecule such as collagens I and III, decorin, prolyl 4-hydroxylase (P4H), lysyl oxidase (LOX), TIMP-1 and TIMP-2, but could significantly down regulate the gene expression of MMP-1 and IL-6. In conclusion, low O(2) tension culture can significantly enhance the expansion capacity of tenocytes without affecting their phenotype and functions. PMID: 19821074 [PubMed - indexed for MEDLINE] | | |
| Porous bioactive diopside (CaMgSi(2)O(6)) ceramic microspheres for drug delivery.
March 3, 2010 at 6:08 AM
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| | Porous bioactive diopside (CaMgSi(2)O(6)) ceramic microspheres for drug delivery. Acta Biomater. 2010 Mar;6(3):820-9 Authors: Wu C, Zreiqat H Ideal bioceramic microspheres for bone regeneration need to be bioactive and degradable, but at the same time possess a controlled drug-release ability. The main disadvantage of the currently available microspheres is their failure to combine these properties. The aim of this study is to develop bioactive ceramic microspheres with optimal properties for use in bone-tissue regeneration. In this study, we utilize diopside (CaMgSi(2)O(6), DP) with proven excellent bioactivity and degradation ability to develop microspheres by controlling their porosity and size, and further modify their surface with polymer to enhance and control their drug-loading/release ability. The phase composition, surface and inner microstructure, and porosity of DP microspheres were tested. Results indicate that carbon powders as porogens with various contents determined the porosity of the porous DP microspheres. The drug-loading and release ability of dexamethazone (DEX) from porous DP micr! ospheres was regulated by their porosity and size. Poly(lactide-co-glycolide) modification forms a film on the surface of DP microspheres and resulted in an enhanced DEX-loading and release ability of the microspheres. Results presented here indicate that the developed DP microspheres have the potential to be used as bioactive filling materials for bone-tissue regeneration. PMID: 19800428 [PubMed - indexed for MEDLINE] | | |
| Reactive calcium-phosphate-containing poly(ester-co-ether) methacrylate bone adhesives: chemical, mechanical and biological considerations.
March 3, 2010 at 6:08 AM
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| | Reactive calcium-phosphate-containing poly(ester-co-ether) methacrylate bone adhesives: chemical, mechanical and biological considerations. Acta Biomater. 2010 Mar;6(3):845-55 Authors: Zhao X, Olsen I, Li H, Gellynck K, Buxton PG, Knowles JC, Salih V, Young AM A poly(propylene glycol-co-lactide) dimethacrylate adhesive with monocalcium phosphate monohydrate (MCPM)/beta-tricalcium phosphate (beta-TCP) fillers in various levels has been investigated. Water sorption by the photo-polymerized materials catalyzed varying filler conversion to dicalcium phosphate (DCP). Polymer modulus was found to be enhanced upon raising total calcium phosphate content. With greater DCP levels, faster release of phosphate and calcium ions and improved buffering of polymer degradation products were observed. This could reduce the likelihood of pH-catalyzed bulk degradation and localized acid production and thereby may prevent adverse biological responses. Bone-like MG-63 cells were found to attach, spread and have normal morphology on both the polymer and composite surfaces. Moreover, composites implanted into chick embryo femurs became closely apposed to the host tissue and did not appear to induce adverse immunological reaction. The above re! sults suggest that the new composite materials hold promise as clinical effective bone adhesives. PMID: 19800424 [PubMed - indexed for MEDLINE] | | |
| In vitro cellular response and in vivo primary osteointegration of electrochemically modified titanium.
March 3, 2010 at 6:08 AM
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| | In vitro cellular response and in vivo primary osteointegration of electrochemically modified titanium. Acta Biomater. 2010 Mar;6(3):1014-24 Authors: Ravanetti F, Borghetti P, De Angelis E, Chiesa R, Martini FM, Gabbi C, Cacchioli A Anodic spark deposition (ASD) is an attractive technique for improving the implant-bone interface that can be applied to titanium and titanium alloys. This technique produces a surface with microporous morphology and an oxide layer enriched with calcium and phosphorus. The aim of the present study was to investigate the biological response in vitro using primary human osteoblasts as a cellular model and the osteogenic primary response in vivo within a short experimental time frame (2 and 4 weeks) in an animal model (rabbit). Responses were assessed by comparing the new electrochemical biomimetic treatments to an acid-etching treatment as control. The in vitro biological response was characterized by cell morphology, adhesion, proliferation activity and cell metabolic activity. A complete assessment of osteogenic activity in vivo was achieved by estimating static and dynamic histomorphometric parameters at several time points within the considered time frame. The i! n vitro study showed enhanced osteoblast adhesion and higher metabolic activity for the ASD-treated surfaces during the first days after seeding compared to the control titanium. For the ASD surfaces, the histomorphometry indicated a higher mineral apposition rate within 2 weeks and a more extended bone activation within the first week after surgery, leading to more extensive bone-implant contact after 2 weeks. In conclusion, the ASD surface treatments enhanced the biological response in vitro, promoting an early osteoblast adhesion, and the osteointegrative properties in vivo, accelerating the primary osteogenic response. PMID: 19800423 [PubMed - indexed for MEDLINE] | | |
| Biotinylation of silicon-doped hydroxyapatite: a new approach to protein fixation for bone tissue regeneration.
March 3, 2010 at 6:08 AM
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| | Biotinylation of silicon-doped hydroxyapatite: a new approach to protein fixation for bone tissue regeneration. Acta Biomater. 2010 Mar;6(3):743-9 Authors: Baeza A, Izquierdo-Barba I, Vallet-Regí M Silicon-doped hydroxyapatite has been functionalized with biotin molecules as a new methodology for the attachment of proteins, peptides or growth factors through the formation of avidin-biotin complex in this material. Bioceramic biotinylation has been performed by esterification reaction between the OH groups of hydroxyapatite and COOH groups of biotin molecules. Several parameters of the biotinylation, such as the addition of N,N'-dicyclohexylcarbodiimide (DCC), the biotin/bioceramic molar ratio and the activation time, have been studied in order to improve both the amount of anchored biotin on the bioceramic surface and its bond strength. The grafting of biotin on a silicon-doped hydroxyapatite surface was determined using (13)C nuclear magnetic resonance, Fourier transform infrared spectroscopy and elemental analyses. The results show that the addition of DCC significantly increases both the amount of biotin grafted and the bond strength, because the major pa! rt is through covalent bonding. Lixiviation studies in simulated body fluid (SBF) at 37 degrees C have confirmed such results, showing that the retention grade after 7 days in SBF was of ca. 63%. Fluorescein isothiocyanate-avidin complexation has been performed on three-dimensional (3-D) scaffolds prepared by a rapid-prototyping technique. Confocal microscopy studies show a homogeneous distribution with a higher incorporation rate of the protein over the entire external surface of the biotinylated 3-D scaffold. PMID: 19751850 [PubMed - indexed for MEDLINE] | | |
| Preparation of aligned porous gelatin scaffolds by unidirectional freeze-drying method.
March 3, 2010 at 6:08 AM
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| | Preparation of aligned porous gelatin scaffolds by unidirectional freeze-drying method. Acta Biomater. 2010 Mar;6(3):1167-77 Authors: Wu X, Liu Y, Li X, Wen P, Zhang Y, Long Y, Wang X, Guo Y, Xing F, Gao J Porous gelatin scaffolds with microtubule orientation structure were manufactured by unidirectional freeze-drying technology, and their porous structure was characterized by scanning electron microscopy. Scaffolds with tunable pore size and high porosity up to 98% were obtained by adjusting the concentration of the gelatin solution and crosslinking agent during the preparation process. All the porous gelatin scaffolds exhibited oriented microtubule pores, with width and length from 50 to 100 microm and 100 to 500 microm, respectively. Meanwhile, the properties of the scaffolds, such as porosity, water adsorption ability and compressive strength, were studied. In vitro enzymatic degradation results showed that the absolute weight loss of the gelatin scaffolds exhibited an increasing trend from low to high gelatin concentration used to prepare gelatin scaffolds; in vitro cell culture results indicated that the porous gelatin scaffolds were non-toxic to cartilage cel! ls, since the cells spread and grew well. PMID: 19733699 [PubMed - indexed for MEDLINE] | | |
| Development of an Ibuprofen-releasing biodegradable PLA/PGA electrospun scaffold for tissue regeneration.
March 3, 2010 at 6:08 AM
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| | Development of an Ibuprofen-releasing biodegradable PLA/PGA electrospun scaffold for tissue regeneration. Biotechnol Bioeng. 2010 Feb 1;105(2):396-408 Authors: Cantón I, Mckean R, Charnley M, Blackwood KA, Fiorica C, Ryan AJ, MacNeil S Our aim was to develop a biodegradable fibrous dressing to act as a tissue guide for in situ wound repair while releasing Ibuprofen to reduce inflammation in wounds and reduce pain for patients on dressing changes. Dissolving the acid form of Ibuprofen (from 1% to 10% by weight) in the same solvent as 75% polylactide, 25% polyglycolide (PLGA) polymers gave uniformly loaded electrospun fibers which gave rapid release of drug within the first 8 h and then slower release over several days. Scaffolds with 10% Ibuprofen degraded within 6 days. The Ibuprofen released from these scaffolds significantly reduced the response of fibroblasts to major pro-inflammatory stimulators. Fibroblast attachment and proliferation on scaffolds was unaffected by the addition of 1-5% Ibuprofen. Scaffolds loaded with 10% Ibuprofen initially showed reduced cell attachment but this was restored by soaking scaffolds in media for 24 h. In summary, addition of Ibuprofen to electrospun biodegrad! able scaffolds can give acute protection of adjacent cells to inflammation while the scaffolds provide an open 3D fibrous network to which cells can attach and migrate. By 6 days, such scaffolds will have completely dissolved into the wound bed obviating any need for dressing removal. PMID: 19731254 [PubMed - indexed for MEDLINE] | | |
| Osteostatin-loaded bioceramics stimulate osteoblastic growth and differentiation.
March 3, 2010 at 6:08 AM
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| | Osteostatin-loaded bioceramics stimulate osteoblastic growth and differentiation. Acta Biomater. 2010 Mar;6(3):797-803 Authors: Lozano D, Manzano M, Doadrio JC, Salinas AJ, Vallet-Regí M, Gómez-Barrena E, Esbrit P Parathyroid hormone-related protein (PTHrP) is an important regulator of bone remodeling. Recent studies show that this protein can induce osteogenic features through its N- and C-terminal domains. Silica-based ordered mesoporous bioceramics with an SBA-15 structure - known to be bioactive and biocompatible - have recently been evaluated for their capacity to uptake and deliver L-tryptophan. This amino acid corresponds to the end position of the 107-111 domain (called osteostatin) of the native C-terminal PTHrP (107-139) fragment, whose true action in bone metabolism is still ill-defined. In the present study, we assessed some effects of the aforementioned biomaterials pressed into disks, loaded or not with osteostatin, in osteoblastic cell cultures. Our data demonstrate that both unmodified and organically modified SBA-15 loaded with this peptide increase cell growth and the expression of several osteoblastic products (alkaline phosphatase, osteocalcin, collagen,! osteoprotegerin, receptor activator of nuclear factor-kappaB ligand and vascular endothelial growth factor) in osteoblastic cells. These findings support the notion that osteostatin coating confers osteogenic features to silica-based ordered mesoporous materials, which make them suitable biomaterials for bone repair. PMID: 19716446 [PubMed - indexed for MEDLINE] | | |
| Vascularization of wide pore agarose-gelatin cryogel scaffolds implanted subcutaneously in diabetic and non-diabetic mice.
March 3, 2010 at 6:08 AM
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| | Vascularization of wide pore agarose-gelatin cryogel scaffolds implanted subcutaneously in diabetic and non-diabetic mice. Acta Biomater. 2010 Mar;6(3):1200-5 Authors: Bloch K, Vanichkin A, Damshkaln LG, Lozinsky VI, Vardi P Polymeric scaffolds have been reported to promote angiogenesis, facilitating oxygen delivery; however, little is known about the effect of diabetes on the neo-vascularization of implanted polymeric scaffolds at subcutaneous (SC) sites. In this study we compare the effect of diabetes on scaffold vascularization following SC implantation into diabetic and non-diabetic mice. Wide pore agarose cryogel scaffolds with grafted gelatin were prepared by a two-step freezing procedure and subsequent thawing. The scaffolds were implanted subcutaneously into streptozoticin-induced diabetic mice and control, non-diabetic mice. The vascularization process was estimated using histological sections, in which endothelial cells were identified by Von Willebrand factor (vWF) and CD31 antigen staining and the pericyte layer was confirmed by alpha-smooth muscle actin (alpha-SMA) visualization. Comparative analysis showed a similar thickness of fibrous capsules around the vascularized s! caffolds in both diabetic and non-diabetic animals. Intensive staining for alpha-SMA indicated the formation of mature blood vessels in the surrounding fibrous capsule and tissue invading the scaffold area. No statistically significant differences in capillary density and area occupied by blood vessels were found between diabetic and non-diabetic mice. In conclusion, the present study shows no adverse effects of diabetes on new blood vessel formation in SC implanted agarose cryogel scaffolds with grafted gelatin. PMID: 19703598 [PubMed - indexed for MEDLINE] | | |
| The role of surface wettability and surface charge of electrosprayed nanoapatites on the behaviour of osteoblasts.
March 3, 2010 at 6:08 AM
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| | The role of surface wettability and surface charge of electrosprayed nanoapatites on the behaviour of osteoblasts. Acta Biomater. 2010 Mar;6(3):750-5 Authors: Thian ES, Ahmad Z, Huang J, Edirisinghe MJ, Jayasinghe SN, Ireland DC, Brooks RA, Rushton N, Bonfield W, Best SM A new deposition method is presented, based on electrospraying, that can build bioceramic structures with desirable surface properties. This technology allows nanoapatite crystals, including hydroxyapatite (nHA), carbonate-substituted HA (nCHA) and silicon-substituted HA (nSiHA), to be electrosprayed on glass substrates. Human osteoblast cells cultured on nSiHA showed enhanced cell attachment, proliferation and protein expression, namely alkaline phosphatase, type 1 collagen and osteocalcin, as compared to nHA and nCHA. The modification of nanoapatite by the addition of silicon into the HA lattice structure renders the electrosprayed surface more hydrophilic and electronegatively charged. PMID: 19671453 [PubMed - indexed for MEDLINE] | | |
| Synthesis, characterizations and biocompatibility of novel biodegradable star block copolymers based on poly[(R)-3-hydroxybutyrate] and poly(epsilon-caprolactone).
March 3, 2010 at 6:08 AM
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| | Synthesis, characterizations and biocompatibility of novel biodegradable star block copolymers based on poly[(R)-3-hydroxybutyrate] and poly(epsilon-caprolactone). Acta Biomater. 2010 Mar;6(3):1079-89 Authors: Wu L, Wang L, Wang X, Xu K Star block copolymers based on poly[(R)-3-hydroxybutyrate] (PHB) and poly(epsilon-caprolactone) (PCL), termed SPHBCL, were successfully synthesized with structural variation on arm numbers and lengths via coupling reactions and ring opening polymerizations. Arm numbers 3, 4 and 6 of SPHBCL were synthesized by using different multifunctional cores, such as trimethyol propane, pentaerythiritol and dipentaerthritol, respectively. Gel permeation chromatography (GPC) and (1)H and (13)C nuclear magnetic resonance were used to characterize the structure of SPHBCL. GPC failed to produce accurate molecular weights of the SPHBCL due to the discrepancy of star copolymer structures. The melting temperature of SPHBCL decreased with increasing degree of branching. Thermal decomposition temperature was revealed to be lower than that of linear block copolymer LPHBCL counterparts based on PHB and PCL. Films made from various SPHBCL copolymers had different porous or networking sur! face morphology, and all possessed improved biocompatibility in terms of less blood clotting and more osteoblast cell growth compared with their corresponding homopolymers PHB and PCL. Among them, it was found, however, that the 4-arm star block copolymer 4SPHBCL-25 showed unique surface properties, i.e. a regular nanoravine structure was observed by scanning electron microscopy and atomic force microscopy. This 4-arm star copolymer also showed the best biocompatibility. PMID: 19671452 [PubMed - indexed for MEDLINE] | | |
| In vitro characterization of polycaprolactone matrices generated in aqueous media.
March 3, 2010 at 6:08 AM
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| | In vitro characterization of polycaprolactone matrices generated in aqueous media. Acta Biomater. 2010 Mar;6(3):1061-8 Authors: Pok SW, Wallace KN, Madihally SV In this study, a novel process of dissolving polycaprolactone (PCL) matrices in glacial acetic acid was explored in which matrices spontaneously formed upon contact with water. Scanning electron microscopy analysis showed rough architecture and holes on the self-assembled matrix relative to matrices formed after dissolving in chloroform. Immersion in the gelatin solution reduced its roughness and number of micropores. Atomic force microscopy (AFM) analysis confirmed the increased roughness of the self-assembled matrices. The roughness of the matrices decreased after incubation in 1N NaOH for 10 min. AFM analysis also revealed that the self-assembled matrix had a net positive surface charge, whereas chloroform-cast matrix had a negative surface charge. The surface charge of self-assembled matrix after immersion in gelatin changed to negative. However, incubation in NaOH did not affect the surface charge. The tensile properties were tested in both the dry state (25 ! degrees Celsius) and the wet state (37 degrees Celsius) by immersion in phosphate-buffered saline. Self-assembled matrix had lower elastic modulus, break stress and break strain than chloroform-cast matrix in both states. The elastic modulus in the wet condition was reduced by half in self-assembled matrix but tensile strain increased. Samples were further analyzed by ramp-hold test for assessing stress relaxation behavior. Both self-assembled and chloroform-cast matrices had similar trends in stress relaxation behavior. However, stress accumulation in self-assembled matrix was half that of chloroform-cast matrix. In vitro cell cultures were conducted using human foreskin fibroblast (HFF-1) in serum-free medium. Cytoskeletal actin staining showed cell adhesion and spreading on all matrices. Cell retention was significantly increased in self-assembled matrix compared to chloroform-cast matrix. Addition of gelatin improved the retention of seeded cells on the surface. In summ! ary, PCL matrices generated using this novel technique show si! gnifican t promise in biomedical applications. PMID: 19664731 [PubMed - indexed for MEDLINE] | | |
| Biodegradable polymer coating promotes the epithelization of tissue-engineered airway prostheses.
March 3, 2010 at 6:08 AM
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| | Biodegradable polymer coating promotes the epithelization of tissue-engineered airway prostheses. J Thorac Cardiovasc Surg. 2010 Jan;139(1):26-31 Authors: Sato T, Araki M, Nakajima N, Omori K, Nakamura T OBJECTIVE: We have developed a prosthesis that includes a collagen layer for tracheobronchial reconstruction and applied it in a canine model. In previous studies luminal epithelization remained partial or rather slow because of the early disintegration of the collagen layer. We have improved this type of prosthesis by coating the luminal surface with a biodegradable polymer, which serves to protect the collagen layer. The effect of the polymer coating on the epithelization of the luminal surface of the prosthesis was examined. METHODS: The main frame consisted of a polypropylene mesh tube, measuring 15 mm in inner diameter and 30 mm in length, with reinforcing rings. Collagen extracted from porcine skin was conjugated to this frame. The luminal surface was coated with a polymer, poly (L-lactic-acid-co-epsilon-caprolactone). In 5 beagle dogs the left main bronchus was replaced with this prosthesis, periodic bronchoscopic observations were conducted, and microscopi! c evaluations were performed. RESULTS: All dogs survived until they were killed, except for 1 animal in which pneumonia developed, and this animal died at 13 months after replacement. None of the dogs showed adverse complications caused by the prosthesis. Bronchoscopic observations revealed that the polymer remained on the luminal surface for 2 weeks. The luminal surface in 4 dogs was completely covered with ciliated columnar epithelium or nonciliated squamous epithelium, and 90% epithelization was achieved in 1 dog. CONCLUSIONS: The biodegradable polymer coating protected the collagen layer and promoted better epithelization. This improved epithelization on the luminal surface could therefore potentially increase the success rates in airway replacement with artificial prostheses. PMID: 19660391 [PubMed - indexed for MEDLINE] | | |
| Evaluation of lyophilized platelets as an infusible hemostatic agent in experimental non-compressible hemorrhage in swine.
March 3, 2010 at 6:08 AM
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| | Evaluation of lyophilized platelets as an infusible hemostatic agent in experimental non-compressible hemorrhage in swine. J Thromb Haemost. 2009 Oct;7(10):1663-71 Authors: Hawksworth JS, Elster EA, Fryer D, Sheppard F, Morthole V, Krishnamurthy G, Tomori T, Brown TS, Tadaki DK INTRODUCTION: Human lyophilized platelets hold promise as a novel hemostatic infusion agent for the control of traumatic hemorrhage. Rehydrated, lyophilized platelets (Stasix) were investigated as an infusible hemostatic agent in experimental non-compressible hemorrhage, using a porcine liver injury model. METHODS: Yorkshire swine underwent a grade III liver injury and uncontrolled bleeding. After 15 min, animals were infused with Stasix (n = 10) or normal saline vehicle (n = 10). At 2 h, the liver was repaired, and the animals were monitored for another4 h. Resuscitation, including blood transfusion, was administered during the hospital phase. Laboratory data, including arterial blood gas, complete blood count, thromboelastography (TEG), and coagulation parameters, were collected. All animals underwent necropsy with complete histopathologic examination. RESULTS: Overall survival in the Stasix group [8/10 (80%)] was significantly higher than in the control group [! 2/10 (20%)] (P = 0.023). Mean total blood loss index (g kg(-1)) was lower in Stasix-treated animals (22.2 +/- 3.5) than in control animals (34.7 +/- 3.4) (P = 0.019). Hemodynamic parameters were improved in the Stasix group, and a trend towards higher hemoglobin and lower lactate was observed. Coagulation and TEG parameters were not different between the groups. One surviving animal in the Stasix group had evidence of thrombi on necropsy. CONCLUSIONS: This is the first reported study to evaluate rehydrated, lyophilized platelets as an infusible hemostatic agent for non-compressible hemorrhage. Stasix improved survival and reduced blood loss in a liver injury porcine model. However, evidence of thrombotic complications warrants further investigation prior to human use in the setting of traumatic hemorrhage. PMID: 19656278 [PubMed - indexed for MEDLINE] | | |
| Effect of protocatechuic acid from Alpinia oxyphylla on proliferation of human adipose tissue-derived stromal cells in vitro.
March 3, 2010 at 6:08 AM
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| | Effect of protocatechuic acid from Alpinia oxyphylla on proliferation of human adipose tissue-derived stromal cells in vitro. Mol Cell Biochem. 2009 Oct;330(1-2):47-53 Authors: Wang H, Liu TQ, Zhu YX, Guan S, Ma XH, Cui ZF The effect of protocatechuic acid (PCA) from Alpinia oxyphylla and catapol from Rehmannia on the proliferation capacity of human adipose tissue-derived stromal cells (hADSCs) was investigated in vitro. Cell counts showed that treatment of hADSCs with PCA for 48 h increased the cell number in a dose-dependent manner, while no obvious effect of catapol on the proliferation of hADSCs was observed. In addition, the cell number of hADSCs treated by 1.5 mM PCA increased in a time-dependent manner. The flow cytometric analysis of DNA content demonstrated the cell cycle progress from the G0/G1 phase to the S phase. Western blot analysis revealed the elevated expression of cyclin D1 in hADSCs induced by PCA treatment. Cyclin D1-siRNA transfection significantly inhibit the promotion of cell proliferation by PCA. Furthermore, the flow cytometric analysis of the cell surface antigens and the multidifferential potential tests of PCA-treated hADSCs showed that the cells retaine! d their functional characteristics of multipotential mesenchymal progenitors. It is concluded that PCA can effectively up-regulate the proliferation of hADSCs. PMID: 19363594 [PubMed - indexed for MEDLINE] | | |
| Bone augmentation by bone marrow mesenchymal stem cells cultured in three-dimensional biodegradable polymer scaffolds.
March 3, 2010 at 6:08 AM
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| | Bone augmentation by bone marrow mesenchymal stem cells cultured in three-dimensional biodegradable polymer scaffolds. J Biomed Mater Res A. 2009 Nov;91(2):428-35 Authors: Tanaka T, Hirose M, Kotobuki N, Tadokoro M, Ohgushi H, Fukuchi T, Sato J, Seto K Poly-lactic-glycolic acid (PLGA) is a biocompatible as well as biodegradable polymer and used in various medical applications. In this study, we evaluated efficiency of the specially designed three-dimensional porous PLGA as a scaffold for bone augmentation. First, cell attachment/proliferation, differentiation, and mineralization of Fisher 344 rat marrow mesenchymal stem cells (MSCs) cultured on the PLGA scaffold were analyzed. Viable MSCs were impregnated into pore areas of the scaffold and a moderate increase of DNA contents was seen. High alkaline phosphatase, osteocalcin content, and calcium content of MSCs in PLGA scaffolds under osteogenic differentiation conditions were seen after 14 or 21 days of culture. Subsequently, we implanted the PLGA/MSCs composites on rat calvaria bone for 30 days. Newly formed bone was seen in only the composite PLGA/MSCs implantation group, which had been precultured under osteogenic condition. We also demonstrated that the newl! y formed bone originated from the donor composites. These results demonstrate that the three-dimensional PLGA scaffold can support osteogenic differentiation of MSCs, and the scaffold combined with osteogenic MSCs can be used for in vivo bone tissue augmentation. PMID: 18985782 [PubMed - indexed for MEDLINE] | | |
| Effects of nerve growth factor from genipin-crosslinked gelatin in polycaprolactone conduit on peripheral nerve regeneration--in vitro and in vivo.
March 3, 2010 at 6:08 AM
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| | Effects of nerve growth factor from genipin-crosslinked gelatin in polycaprolactone conduit on peripheral nerve regeneration--in vitro and in vivo. J Biomed Mater Res A. 2009 Nov;91(2):586-96 Authors: Chang CJ The gelatin solution crosslinked by genipin (0, 0.1, 0.5, 1.0, and 1.5% w/w) was studied as a nerve growth factor (NGF) carrier (GGp0, GGp0.1, GGp0.5, GGp1.0, and GGp1.5) in a polycaprolactone conduit in large-gap nerve regeneration. The GGp0 and GGp0.1 displayed the highest activity of PC12 cells and inhibited the reduction of 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide (MTT). No cytotoxicity was found in all groups by lactate dehydrogenase (LDH) release. The NGF-releasing characters were obtained by ELISA tests. A relatively fast release rate appeared during the first 10 days and then a subsequent slower release profile followed. NGF was higher in GGp0.1 than in GGp0 and GGp0.1 after 10 days. The bioactivity of the released NGF remains the same when measuring the neurite outgrowth of PC 12 cells. Finally, the controlled-release conduits were implanted into 12-mm long sciatic nerve gaps of rats. In addition, the best site of NGF carrier was deter! mined either by filling carrier into the conduit lumen or by sucking carrier to the conduit wall. Four and 8 weeks after implantation, morphological analysis revealed that GGp0.1 conduits had markedly larger and more number of myelin axons in the midconduit and distal nerve. Further, sucking the carrier into the conduit wall was an efficient and convenient way to prevent the regeneration of axons and vessels from being impaired by the lumen's carrier. The genipin-crosslinked gelatin is a promising carrier in producing a high release concentration and a long release period of NGF to promote the regeneration over a large-gap nerve injury. PMID: 18985781 [PubMed - indexed for MEDLINE] | | |
| Calcium phosphate surface treatment of bioactive glass causes a delay in early osteogenic differentiation of adipose stem cells.
March 3, 2010 at 6:08 AM
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| | Calcium phosphate surface treatment of bioactive glass causes a delay in early osteogenic differentiation of adipose stem cells. J Biomed Mater Res A. 2009 Nov;91(2):540-7 Authors: Haimi S, Moimas L, Pirhonen E, Lindroos B, Huhtala H, Räty S, Kuokkanen H, Sándor GK, Miettinen S, Suuronen R Human adipose stem cells (ASCs) combined with osteostimulative material provide an attractive approach for clinical bone regeneration. The effect of calcium phosphate (Ca-P) surface treatment of three-dimensional bioactive glass scaffolds on the attachment, proliferation, and osteogenic differentiation of ASCs was studied. Three types of bioactive glass scaffolds (nontreated, thick and thin Ca-P treated) were compared. All scaffold types supported ASC attachment, spreading, and proliferation equally as detected by scanning electron microscopy, fluorescence staining, and DNA measurement. Indices of osteogenic differentiation including the expression of osteopontin and alkaline phosphatase (ALP) were consistently higher in the nontreated and thin Ca-P-treated scaffolds when compared with thick Ca-P-treated scaffolds at 2 weeks. ASCs cultured on nontreated bioactive glass scaffolds showed significantly higher ALP activity when compared with both thin and thick Ca-P-t! reated scaffolds after 1 week in culture, but these differences equalized between the three scaffolds by the 2-week time point. In conclusion, osteogenic differentiation appears to be delayed on the Ca-P surface-treated scaffolds. This delay is more pronounced with thick Ca-P treatment of the scaffolds. PMID: 18985777 [PubMed - indexed for MEDLINE] | | |
| Self-setting collagen-calcium phosphate bone cement: mechanical and cellular properties.
March 3, 2010 at 6:08 AM
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| | Self-setting collagen-calcium phosphate bone cement: mechanical and cellular properties. J Biomed Mater Res A. 2009 Nov;91(2):605-13 Authors: Moreau JL, Weir MD, Xu HH Calcium phosphate cement (CPC) can conform to complex bone cavities and set in-situ to form bioresorbable hydroxyapatite. The aim of this study was to develop a CPC-collagen composite with improved fracture resistance, and to investigate the effects of collagen on mechanical and cellular properties. A type-I bovine-collagen was incorporated into CPC. MC3T3-E1 osteoblasts were cultured. At CPC powder/liquid mass ratio of 3, the work-of-fracture (mean +/- sd; n = 6) was increased from (22 +/- 4) J/m(2) at 0% collagen, to (381 +/- 119) J/m(2) at 5% collagen (p < or = 0.05). At 2.5-5% of collagen, the flexural strength at powder/liquid ratios of 3 and 3.5 was 8-10 MPa. They matched the previously reported 2-11 MPa of sintered porous hydroxyapatite implants. SEM revealed that the collagen fibers were covered with nano-apatite crystals and bonded to the CPC matrix. Higher collagen content increased the osteoblast cell attachment (p < or = 0.05). The number of live! cells per specimen area was (382 +/- 99) cells/mm(2) on CPC containing 5% collagen, higher than (173 +/- 42) cells/mm(2) at 0% collagen (p < or = 0.05). The cytoplasmic extensions of the cells anchored to the nano-apatite crystals of the CPC matrix. In summary, collagen was incorporated into in situ-setting, nano-apatitic CPC, achieving a 10-fold increase in work-of-fracture (toughness) and two-fold increase in osteoblast cell attachment. This moldable/injectable, mechanically strong, nano-apatite-collagen composite may enhance bone regeneration in moderate stress-bearing applications. PMID: 18985758 [PubMed - indexed for MEDLINE] | | | | 
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