| Please add updates@feedmyinbox.com to your address book to make sure you receive these messages in the future. | |
| Telling the California Stem Cell Story: $1 Million for PR/Communications and More Likely
March 3, 2010 at 1:07 PM
|
| The California stem cell agency is already spending more than $1 million on selling itself, but its directors could be asked next week to bump up that figure substantially.
The subject will come up Tuesday at the first meeting of the directors' new subcommittee on communications, chaired by Robert Klein, a Palo Alto real estate investment banker who is also chairman of CIRM. Topic one on his | | |
| Analysis of CIRM Challenges on HealthyCal
March 3, 2010 at 12:29 PM
|
| HealthyCal, a Web site dealing with health issues facing California, has published an analytical overview of the California stem cell agency written by the publisher of this Web site.
It begins:
"A little more than five years ago, visions of seemingly magical stem cell cures danced in the minds of California voters. Lured by the promise of human embryonic stem cells and the intransigence of the | | |
| Immune physiology in tissue regeneration and aging, tumor growth, and regenerative medicine.
March 3, 2010 at 7:58 AM
|
| | 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] | | |
| Exploring cellular adhesion and differentiation in a micro-/nano-hybrid polymer scaffold.
March 3, 2010 at 6:39 AM
|
| | 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 6:39 AM
|
| | 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 6:39 AM
|
| | 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 6:39 AM
|
| | 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 6:39 AM
|
| | 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] | | |
| Synergistic effects of electrospun PLLA fiber dimension and pattern on neonatal mouse cerebellum C17.2 stem cells.
March 3, 2010 at 6:39 AM
|
| | 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 6:39 AM
|
| | 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 6:39 AM
|
| | 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] | | |
| Predifferentiated adult stem cells and matrices for cardiac cell therapy.
March 3, 2010 at 6:39 AM
|
| | Predifferentiated adult stem cells and matrices for cardiac cell therapy. Asian Cardiovasc Thorac Ann. 2010 Feb;18(1):79-87 Authors: Spadaccio C, Chachques E, Chello M, Covino E, Chachques JC, Genovese J Stem cell therapy is a major field of research worldwide, with increasing clinical application, especially in cardiovascular pathology. However, the best stem cell source and type with optimal safety for functional engraftment remains unclear. An intermediate cardiac precommitted phenotype expressing some of the key proteins of a mature cardiomyocyte would permit better integration into the cardiac environment. The predifferentiated cells would receive signals from the environment, thus achieving gradual and complete differentiation. In cell transplantation, survival and engraftment within the environment of the ischemic myocardium represents a challenge for all types of cells, regardless of their state of differentiation. An alternative strategy is to embed cells in a 3-dimensional structure replicating the extracellular matrix, which is crucial for full tissue restoration and prevention of ventricular remodeling. The clinical translation of cell therapy requires! avoidance of potentially harmful drugs and cytokines, and rapid off-the-shelf availability of cells. The combination of predifferentiated cells with a functionalized scaffold, locally releasing molecules tailored to promote in-situ completion of differentiation and improve homing, survival, and function, could be an exciting approach that might circumvent the potential undesired effects of growth factor administration and improve tissue restoration. PMID: 20124305 [PubMed - indexed for MEDLINE] | | |
| Late-term results of tissue-engineered vascular grafts in humans.
March 3, 2010 at 6:39 AM
|
| | 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] | | |
| Both epithelial cells and mesenchymal stem cell-derived chondrocytes contribute to the survival of tissue-engineered airway transplants in pigs.
March 3, 2010 at 6:39 AM
|
| | 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] | | |
| In vitro myogenic and adipogenic differentiation model of genetically engineered bovine embryonic fibroblast cell lines.
March 3, 2010 at 6:39 AM
|
| | 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] | | |
| Post-culture treatment protocols for PLGA membrane scaffolds.
March 3, 2010 at 6:39 AM
|
| | 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] | | |
| In vitro cellular response and in vivo primary osteointegration of electrochemically modified titanium.
March 3, 2010 at 6:39 AM
|
| | 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 6:39 AM
|
| | 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 6:39 AM
|
| | 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 6:39 AM
|
| | 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 6:39 AM
|
| | 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 6:39 AM
|
| | 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 6:39 AM
|
| | 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] | | | | 
| This email was sent to regenmd@gmail.com. Account Login
Don't want to receive this feed any longer? Unsubscribe here
This email was carefully delivered by Feed My Inbox. 230 Franklin Road Suite 814 Franklin, TN 37064 | |
No comments:
Post a Comment