| Emerging drugs for acute myocardial infarction.
January 10, 2010 at 1:21 PM
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| | Emerging drugs for acute myocardial infarction. Expert Opin Emerg Drugs. 2010 Jan 7; Authors: Lazzeri C, Tarquini R, Valente S, Abbate R, Gensini G Importance of the field: The present review is aimed at going over the pharmacological profile (and the clinical impact) of the emerging drugs involved in the management of patients with ST-elevation myocardial infarction (STEMI) in order to provide the cardiologists who deal with these patients in the early phase with the most recent evidence on this topic.Areas covered in this review: Anticoagulant and antiplatelet drugs are the main cornerstones of therapy in the treatment of STEMI patients undergoing primary percutaneous coronary intervention (PCI). The main issues that clinicians have to deal with are represented by balancing thrombotic and bleeding risks. In tailoring therapy, variables such as age, sex and previous disease should be taken into account, as well as ongoing complications (such as acute renal failure) that could affect hemostasis. Despite the well-established clinical benefits of antiplatelet agents, questions remain, mainly surrounding potenti! al for variable platelet response, which are strictly related to non-genetic (i.e., diet, drug-drug interaction, clinical factors such as obesity, diabetes mellitus, and inflammation) and genetic determinants. What the reader will gain: In their daily practice, cardiologists cannot abstract from the knowledge and updating on the ongoing research fields as well as the newly developed drugs, which they should frame in the very patient in the attempt to the develop a personalized medical strategy. These include also the pharmacological option(s) in the treatment of the reperfusion injury, the metabolic aspects and the stem cell therapy. Take home massage: In our opinion, the goal of ongoing research on the pharmacological approach to STEMI patients is a personalized medical strategy that relies on critical clinicians who merge newly developed acquisitions on this topic and a more complete, systemic and critical approach to the patient. PMID: 20055689 [PubMed - as supplied by publisher] | | |
| Dental Stem Cell therapy with Calcium Hydroxide in Dental Pulp Capping.
January 10, 2010 at 1:21 PM
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| | Dental Stem Cell therapy with Calcium Hydroxide in Dental Pulp Capping. Tissue Eng Part A. 2010 Jan 7; Authors: Ji YM, Jeon SH, Park JY, Chung JH, Choung YH, Choung PH Calcium hydroxide has been extensively and steadily used for direct pulp capping in modern clinical dentistry. As it was known to have potential to induce hard tissue repair, this chemical has been applied to the exposed dental pulp and the hard tissue is expected to be regenerated above the pulp. During the reparative process of exposed pulp, primary odontoblasts lost as a result of extensive damage are replaced with newly differentiated odontoblast-like cells. This process is known to follow the sequential steps of proliferation, migration, and differentiation of progenitor cells. This research will examine the relationship between calcium hydroxide and the recruitment, proliferation and mineralization of postnatal dental stem cells, obtained from an immature dental tissue of beagle dogs. Immunocytochemical staining and RT-PCR were used to identify the putative stem cell markers. Immunoblot analysis, wound healing assay, cell migration assay and Alizarin red sta! ining were used to evaluate proliferation, migration and mineralization capacity of the calcium hydroxide-treated stem cells. As an in vivo study, combination of calcium hydroxide and autogenous dental pulp stem cells was applied for the treatment of intentionally created tooth defects on the premolars and the molars in beagle dogs to observe dentin regeneration. Ex-vivo expanded dental pulp stem cells (DPSCs) and periodontal ligament stem cells (PDLSCs) expressed STRO-1 and CD146, the mesenchymal stem cell markers. It was evident that calcium hydroxide increased recruitment, migration, proliferation and mineralization of the DPSCs and PDLSCs. Such results are valuable for the future availability of the DPSCs, which are recently focused as the stem cell reservoir for regeneration of dentin upon tooth injury, as well as for elucidation of the role of calcium hydroxide in pulp capping therapy. PMID: 20055661 [PubMed - as supplied by publisher] | | |
| Platelet-rich plasma impairs osteoclast generation from human precursors of peripheral blood.
January 9, 2010 at 7:42 AM
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| | Platelet-rich plasma impairs osteoclast generation from human precursors of peripheral blood. J Orthop Res. 2010 Jan 7; Authors: Cenni E, Avnet S, Fotia C, Salerno M, Baldini N Platelet-rich plasma is used to accelerate bone repair for the release of osteogenic growth factors from activated platelets. To date, the effects on osteoclasts have been only scarcely investigated, even though these cells are crucial for bone remodeling. The aim of this research was the evaluation of the effects of thrombin-activated platelets (PRP) on osteoclastogenesis from human blood precursors. We evaluated both the ability to influence osteoclast differentiation induced by the receptor activator of nuclear factor-kappaB ligand (RANKL), and the ability to induce osteoclast differentiation without RANKL. In both assays, the incubation with PRP supernatant at 10% did not significantly affect the formation of tartrate-resistant acid phosphatase (TRACP)-positive multinucleated cells that were able to form the F-actin ring. However, when PRP at 25 and 50% was added to the medium without RANKL, the generation of TRACP-positive multinucleated cells was inhibited. ! PRP, even at 10%, reduced the osteoclast-mediated bone collagen degradation, suggesting inhibition of osteoclast activation. Similarly, after incubation with PRP supernatant, calcitonin receptor mRNA was lower than the untreated samples. In conclusion, PRP at 10% interfered with the complete differentiation process of human osteoclast precursors. At higher concentration it impaired osteoclast formation also at an early stage of differentiation. (c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. PMID: 20058277 [PubMed - as supplied by publisher] | | |
| Silk fibroin microparticles as carriers for delivery of human recombinant BMPs. Physical characterization and drug release.
January 9, 2010 at 7:42 AM
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| | Silk fibroin microparticles as carriers for delivery of human recombinant BMPs. Physical characterization and drug release. J Tissue Eng Regen Med. 2010 Jan 7; Authors: Bessa PC, Balmayor ER, Azevedo HS, Nürnberger S, Casal M, van Griensven M, Reis RL, Redl H Bone morphogenetic proteins (BMPs) are cytokines with strong ability to promote new bone formation. Herein, we report the use of silk fibroin microparticles as carriers for the delivery of BMP-2, BMP-9 or BMP-14. BMP-containing fibroin microparticles were prepared by a mild methodology using dropwise addition of ethanol, exhibiting mean diameters of 2.7 +/- 0.3 microm. Encapsulation efficiencies varied between 67.9 +/- 6.1 % and 97.7 +/- 2.0 % depending on the type and the amount of BMP loaded. Release kinetics showed that BMP-2, BMP-9 and BMP-14 were released in two phases profile, with a burst release in the first two days followed by a slower release, for a period of 14 days. The release data were best explained by Korsmeyer's model and the Fickian model of drug diffusion. Silk fibroin microparticles can offer a promising approach for the sustained delivery of different BMPs in tissue engineering applications. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20058243 [PubMed - as supplied by publisher] | | |
| Developments and challenges in human embryonic stem cell research in Spain.
January 9, 2010 at 7:42 AM
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| | Developments and challenges in human embryonic stem cell research in Spain. Stem Cell Rev. 2009 Dec;5(4):334-9 Authors: Cervera RP, Stojkovic M After years of following the trail of others, Spain is finally making a serious bid in science, specifically in regenerative medicine. In the framework of the European Union, Spain is setting up the basis for a solid collaborative network between public and private institutions, involving basic, translational, applied, technological and clinical researchers. In a society characterised by the idiom "slow but secure", it is still too soon to see the results of the huge economic and infrastructure investment made. We present here an overview of the challenges that have been surmounted and the ones that will have to be solved in order to situate Spain as a reference country in regenerative medicine worldwide. PMID: 20058198 [PubMed - in process] | | |
| Phase transformation behaviour of hydroxyapatite foams subject to heat treatment.
January 9, 2010 at 7:42 AM
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| | Phase transformation behaviour of hydroxyapatite foams subject to heat treatment. Biomed Mater. 2010 Jan 7;5(1):15004 Authors: Finoli A, McKeel D, Gerlach J, Nettleship I This study examined the relationship between sintering and phase transformation behaviour in hydroxyapatite (HA). Pellets and replicated foams were sintered at five different temperatures ranging from 1350 degrees C to 1550 degrees C. Hydroxyapatite remained as the major phase in all the samples studied. In the pellets, sintering took place prior to the phase transformation which occurs primarily at the surface. This created damage that extended into the interior of the pellet above 1400 degrees C. In contrast, the foams transformed at lower temperatures due to the higher surface area. This did not create damage in the foam. The differences in the foams and the pellets are discussed in terms of sintering and phase transformation behaviour. PMID: 20057016 [PubMed - as supplied by publisher] | | |
| Can tissue engineering concepts advance tumor biology research?
January 9, 2010 at 7:42 AM
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| | Can tissue engineering concepts advance tumor biology research? Trends Biotechnol. 2010 Jan 5; Authors: Hutmacher DW, Loessner D, Rizzi S, Kaplan DL, Mooney DJ, Clements JA Advances in tissue engineering have traditionally led to the design of scaffold- or matrix-based culture systems that better reflect the biological, physical and biochemical environment of the natural extracellular matrix. Although their clinical applications in regenerative medicine tend to receive most of the attention, it is obvious that other areas of biomedical research could be well served by the powerful tools that have already been developed in tissue engineering. In this article, we review the recent literature to demonstrate how tissue engineering platforms can enhance in vitro and in vivo models of tumorigenesis and thus hold great promise to contribute to future cancer research. PMID: 20056286 [PubMed - as supplied by publisher] | | |
| Metalloproteinase Expression is Associated with Traumatic Wound Failure.
January 9, 2010 at 7:42 AM
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| | Metalloproteinase Expression is Associated with Traumatic Wound Failure. J Surg Res. 2009 Sep 15; Authors: Utz ER, Elster EA, Tadaki DK, Gage F, Perdue PW, Forsberg JA, Stojadinovic A, Hawksworth JS, Brown TS BACKGROUND: Matrix metalloproteinases (MMPs) are crucial in the inflammatory and remodeling phases of wound healing. We previously reported the correlation between pro-inflammatory cytokines and timing of successful combat-wound closure. We now extend our studies to investigate the correlation between wound-remodeling MMP expression and wound healing. METHODS: Thirty-eight wounds in 25 patients with traumatic extremity combat wounds were prospectively studied. Surgical debridement with vacuum-assisted closure (VAC) device application was repeated every 48 to 72h until surgical wound closure. Wound effluent and patient serum were collected at each wound debridement and analyzed for five matrix metalloproteinases using the Luminex multiplex system; Millipore Corp, Billerica, MA. The primary outcome was wound healing within 30 d of definitive wound closure. Impairment was defined as delayed wound closure (>21 d from injury) or wound dehiscence. MMP expression was ! compared between impaired and normal healing wounds. RESULTS: Elevated levels of serum MMP-2 and MMP-7 and reduced levels of effluent MMP3 were seen in impaired wounds (n = 9) compared with wounds that healed (n = 29; P<0.001). Receiver operating characteristic (ROC) curve analysis yielded area-under-the-curve (AUC) of 0.744, 0.783, and 0.805, respectively. CONCLUSIONS: Impaired wound healing is characterized by pro-inflammatory MMP-2 and MMP-7. Serum and effluent concentrations of MMP-2, MMP-3, and MMP-7 can effectively predict the outcome of traumatic war wounds and can potentially provide decision-supportive, objective evidence for the timing of wound closure. PMID: 20056248 [PubMed - as supplied by publisher] | | |
| Cultivating regenerative medicine innovation in China.
January 9, 2010 at 7:42 AM
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| | Cultivating regenerative medicine innovation in China. Regen Med. 2010 Jan;5(1):35-44 Authors: McMahon DS, Thorsteinsdóttir H, Singer PA, Daar AS AIM: While China has become a significant contributor and prolific publisher in regenerative medicine, its role in the field is not well understood. We analyze how capacity in regenerative medicine was built in China to identify some of its main strengths and challenges. MATERIALS & METHODS: This case study of regenerative medicine in China is primarily based on interviews with experts in China, including researchers, policy makers, clinicians, representatives of firms and regulators. RESULTS: Our analysis shows that diverse groups are active in this field in China. Leading research groups are contributing extensively to international peer-reviewed journals. Strong governmental support and recruitment of highly trained Chinese scientists from abroad has made it possible for China to rapidly build up capacity in regenerative medicine. However, some hospitals in China are offering stem cell therapies with limited scientific evidence supporting their efficacy/saf! ety, and international skepticism of medical research in China presents a challenge to the development of the field. CONCLUSION: China has been able to catapult itself into the forefront of regenerative medicine but needs to address current regulatory challenges in order to secure its position in this emerging field. PMID: 20055687 [PubMed - in process] | | |
| Electrospinning: methods and development of biodegradable nanofibres for drug release.
January 9, 2010 at 7:42 AM
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| | Electrospinning: methods and development of biodegradable nanofibres for drug release. J Biomed Nanotechnol. 2009 Feb;5(1):1-19 Authors: Ashammakhi N, Wimpenny I, Nikkola L, Yang Y It is clear that nanofibrous structures can be used as tools for many applications. It is already known that electrospinning is a highly versatile method of producing nanofibres and recent developments in the technique of electrospinning have led to the development of aligned nanofibres and biphasic, core-sheath fibres which can be used to encapsulate different materials from molecules to cells. Natural extracellular matrix (ECM) contains fibres in both micro and nano-scales and provides a structural scaffold which allows cells to localize, migrate, proliferate and differentiate. Polymer nanofibres can provide the structural cues of ECM. However, current literature gives new hope to further functionalising polymeric nanofibres by using them for drug delivery devices and improving their design to improve control of delivery. By encapsulating active agents within nanofibres (multifunctional nanofibres), a degree of control can be exerted over the release of encapsul! ated agents and therefore, the behaviour of cells can be manipulated for developing effective therapies and is extremely encouraging in the tissue engineering field by combining factors like fibre diameter, alignment and chemicals in new ways. Such multifunctional nanofibre-based systems are already being investigated in vivo. Experiments have shown the significant potential for treatments of disease and engineering of neural and bone tissues. Further, phase III clinical trials of nanofibrous patches for applications in wound treatment were encouraging. Hopefully, clinical applications of these drug delivery devices will follow, to enhance regenerative medicine applications. PMID: 20055102 [PubMed - in process] | | |
| Embryonic stem cell marker expression pattern in human mesenchymal stem cells derived from bone marrow, adipose tissue, heart and dermis.
January 9, 2010 at 6:33 AM
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| | Embryonic stem cell marker expression pattern in human mesenchymal stem cells derived from bone marrow, adipose tissue, heart and dermis. Stem Cell Rev. 2009 Dec;5(4):378-86 Authors: Riekstina U, Cakstina I, Parfejevs V, Hoogduijn M, Jankovskis G, Muiznieks I, Muceniece R, Ancans J Mesenchymal stem cells (MSCs) have been isolated from a variety of human tissues, e.g., bone marrow, adipose tissue, dermis, hair follicles, heart, liver, spleen, dental pulp. Due to their immunomodulatory and regenerative potential MSCs have shown promising results in preclinical and clinical studies for a variety of conditions, such as graft versus host disease (GvHD), Crohn's disease, osteogenesis imperfecta, cartilage damage and myocardial infarction. MSC cultures are composed of heterogeneous cell populations. Complications in defining MSC arise from the fact that different laboratories have employed different tissue sources, extraction, and cultivation methods. Although cell-surface antigens of MSCs have been extensively explored, there is no conclusive evidence that unique stem cells markers are associated with these adult cells. Therefore the aim of this study was to examine expression of embryonic stem cell markers Oct4, Nanog, SOX2, alkaline phosphatase ! and SSEA-4 in adult mesenchymal stem cell populations derived from bone marrow, adipose tissue, dermis and heart. Furthermore, we tested whether human mesenchymal stem cells preserve tissue-specific differences under in vitro culture conditions. We found that bone marrow MSCs express embryonic stem cell markers Oct4, Nanog, alkaline phosphatase and SSEA-4, adipose tissue and dermis MSCs express Oct4, Nanog, SOX2, alkaline phosphatase and SSEA-4, whereas heart MSCs express Oct4, Nanog, SOX2 and SSEA-4. Our results also indicate that human adult mesenchymal stem cells preserve tissue-specific differences under in vitro culture conditions during early passages, as shown by distinct germ layer and embryonic stem cell marker expression patterns. Studies are now needed to determine the functional role of embryonic stem cell markers Oct4, Nanog and SOX2 in adult human MSCs. PMID: 20058201 [PubMed - in process] | | |
| Bone marrow-derived mesenchymal stem cells express the pericyte marker 3G5 in culture and show enhanced chondrogenesis in hypoxic conditions.
January 9, 2010 at 6:29 AM
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| | Bone marrow-derived mesenchymal stem cells express the pericyte marker 3G5 in culture and show enhanced chondrogenesis in hypoxic conditions. J Orthop Res. 2010 Jan 7; Authors: Khan WS, Adesida AB, Tew SR, Lowe ET, Hardingham TE Bone marrow-derived mesenchymal stem cells are a potential source of cells for the repair of articular cartilage defects. Hypoxia has been shown to improve chondrogenesis in some cells. In this study, bone marrow-derived stem cells were characterized and the effects of hypoxia on chondrogenesis investigated. Adherent bone marrow colony-forming cells were characterized for stem cell surface epitopes, and then cultured as cell aggregates in chondrogenic medium under normoxic (20% oxygen) or hypoxic (5% oxygen) conditions. The cells stained strongly for markers of adult mesenchymal stem cells, and a high number of cells were also positive for the pericyte marker 3G5. The cells showed a chondrogenic response in cell aggregate cultures and, in lowered oxygen, there was increased matrix accumulation of proteoglycan, but less cell proliferation. In hypoxia, there was increased expression of key transcription factor SOX6, and of collagens II and XI, and aggrecan. Pericyte! s are a candidate stem cell in many tissue, and our results show that bone marrow-derived mesenchymal stem cells express the pericyte marker 3G5. The response to chondrogenic culture in these cells was enhanced by lowered oxygen tension. This has important implications for tissue engineering applications of bone marrow-derived stem cells. (c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. PMID: 20058274 [PubMed - as supplied by publisher] | | |
| Chondrogenic differentiation and lubricin expression of caprine infraspinatus tendon cells.
January 9, 2010 at 6:29 AM
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| | Chondrogenic differentiation and lubricin expression of caprine infraspinatus tendon cells. J Orthop Res. 2010 Jan 7; Authors: Funakoshi T, Spector M Reparative strategies for the treatment of injuries to tendons, including those of the rotator cuff of the shoulder, need to address the formation of the cartilage which serves as the attachment apparatus to bone and which forms at regions undergoing compressive loading. Moreover, recent work indicates that cells employed for rotator cuff repair may need to synthesize a lubricating glycoprotein, lubricin, which has recently been found to play a role in tendon tribology. The objective of the present study was to investigate the chondrogenic differentiation and lubricin expression of caprine infraspinatus tendon cells in monolayer and three-dimensional culture, and to compare the behavior with bone marrow-derived mesenchymal stem cells (MSCs). The results demonstrated that while tendon cells in various media, including chondrogenic medium, expressed lubricin, virtually none of the MSCs synthesized this important lubricating molecule. Also of interest was that the ca! rtilage formation capacity of the tendon cells grown in pellet culture in chondrogenic medium was comparable with MSCs. These data inform the use of tendon cells for rotator cuff repair, including for fibrocartilaginous zones. (c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. PMID: 20058273 [PubMed - as supplied by publisher] | | |
| Silk fibroin microparticles as carriers for delivery of human recombinant BMPs. Physical characterization and drug release.
January 9, 2010 at 6:29 AM
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| | Silk fibroin microparticles as carriers for delivery of human recombinant BMPs. Physical characterization and drug release. J Tissue Eng Regen Med. 2010 Jan 7; Authors: Bessa PC, Balmayor ER, Azevedo HS, Nürnberger S, Casal M, van Griensven M, Reis RL, Redl H Bone morphogenetic proteins (BMPs) are cytokines with strong ability to promote new bone formation. Herein, we report the use of silk fibroin microparticles as carriers for the delivery of BMP-2, BMP-9 or BMP-14. BMP-containing fibroin microparticles were prepared by a mild methodology using dropwise addition of ethanol, exhibiting mean diameters of 2.7 +/- 0.3 microm. Encapsulation efficiencies varied between 67.9 +/- 6.1 % and 97.7 +/- 2.0 % depending on the type and the amount of BMP loaded. Release kinetics showed that BMP-2, BMP-9 and BMP-14 were released in two phases profile, with a burst release in the first two days followed by a slower release, for a period of 14 days. The release data were best explained by Korsmeyer's model and the Fickian model of drug diffusion. Silk fibroin microparticles can offer a promising approach for the sustained delivery of different BMPs in tissue engineering applications. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20058243 [PubMed - as supplied by publisher] | | |
| Gene-Modified Stem Cells Combined with Rapid Prototyping Techniques: A Novel Strategy for Periodontal Regeneration.
January 9, 2010 at 6:29 AM
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| | Gene-Modified Stem Cells Combined with Rapid Prototyping Techniques: A Novel Strategy for Periodontal Regeneration. Stem Cell Rev. 2010 Jan 8; Authors: He H, Cao J, Wang D, Gu B, Guo H, Liu H Periodontal disease, a worldwide prevalent chronic disease in adults, is characterized by the destruction of the periodontal supporting tissue including the cementum, periodontal ligament and alveolar bone. The regeneration of damaged periodontal tissue is the main goal of periodontal treatment. Because conventional periodontal treatments remain insufficient to attain complete and reliable periodontal regeneration, periodontal tissue engineering has emerged as a prospective alternative method for improving the regenerative capacity of periodontal tissue. However, the potential of periodontal regeneration seems to be limited by the understanding of the cellular and molecular events in the formation of periodontal tissue and by the insufficient collaboration of multi-disciplinary research that periodontal tissue engineering involves. In this paper, we first reviewed the recent advancements in stem cells, signaling factors, and scaffolds that relate to periodontal re! generation. Then we speculate that specific genes would improve regenerative capacity of these stem cells, which could differentiate into cementoblasts, osteoblasts and fibroblasts. In addition, the 3D scaffolds that mimic the different structure and physiologic functions of natural fibro-osseous tissue could be fabricated by rapid prototyping (RP) techniques. It was therefore hypothesized that gene-modified stem cells combined with rapid prototyping techniques would be a new strategy to promote more effective and efficient periodontal regeneration. PMID: 20058102 [PubMed - as supplied by publisher] | | |
| Cellular interfacial and surface tensions determined from aggregate compression tests using a finite element model.
January 9, 2010 at 6:29 AM
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| | Cellular interfacial and surface tensions determined from aggregate compression tests using a finite element model. HFSP J. 2009 Aug;3(4):273-81 Authors: Brodland GW, Yang J, Sweny J Although previous studies suggested that the interfacial tension gamma(cc) acting along cell-cell boundaries and the effective viscosity mu of the cell cytoplasm could be measured by compressing a spherical aggregate of cells between parallel plates, the mechanical understanding necessary to extract this information from these tests-tests that have provided the surface tension sigma(cm) acting along cell-medium interfaces-has been lacking. These tensions can produce net forces at the subcellular level and give rise to cell motions and tissue reorganization, the rates of which are regulated by mu. Here, a three-dimensional (3D) cell-based finite element model provides insight into the mechanics of the compression test, where these same forces are at work, and leads to quantitative relationships from which the effective viscosity mu of the cell cytoplasm, the tension gamma(cc) that acts along internal cell-cell interfaces and the surface tension sigma(cp) along the ! cell-platen boundaries can be determined from force-time curves and aggregate profiles. Tests on 5-day embryonic chick mesencephalon, neural retina, liver, and heart aggregates show that all of these properties vary significantly with cell type, except gamma(cc), which is remarkably constant. These properties are crucial for understanding cell rearrangement and tissue self-organization in contexts that include embryogenesis, cancer metastases, and tissue engineering. PMID: 20057960 [PubMed - in process] | | |
| ECM-Based Materials in Cardiovascular Applications: Inherent Healing Potential and Augmentation of Native Regenerative Processes.
January 9, 2010 at 6:29 AM
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| | ECM-Based Materials in Cardiovascular Applications: Inherent Healing Potential and Augmentation of Native Regenerative Processes. Int J Mol Sci. 2009 Oct;10(10):4375-417 Authors: Piterina AV, Cloonan AJ, Meaney CL, Davis LM, Callanan A, Walsh MT, McGloughlin TM The in vivo healing process of vascular grafts involves the interaction of many contributing factors. The ability of vascular grafts to provide an environment which allows successful accomplishment of this process is extremely difficult. Poor endothelisation, inflammation, infection, occlusion, thrombosis, hyperplasia and pseudoaneurysms are common issues with synthetic grafts in vivo. Advanced materials composed of decellularised extracellular matrices (ECM) have been shown to promote the healing process via modulation of the host immune response, resistance to bacterial infections, allowing re-innervation and reestablishing homeostasis in the healing region. The physiological balance within the newly developed vascular tissue is maintained via the recreation of correct biorheology and mechanotransduction factors including host immune response, infection control, homing and the attraction of progenitor cells and infiltration by host tissue. Here, we review the pr! ogress in this tissue engineering approach, the enhancement potential of ECM materials and future prospects to reach the clinical environment. PMID: 20057951 [PubMed - in process] | | |
| Recent advances in synthetic bioelastomers.
January 9, 2010 at 6:29 AM
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| | Recent advances in synthetic bioelastomers. Int J Mol Sci. 2009 Oct;10(10):4223-56 Authors: Shi R, Chen D, Liu Q, Wu Y, Xu X, Zhang L, Tian W This article reviews the degradability of chemically synthesized bioelastomers, mainly designed for soft tissue repair. These bioelastomers involve biodegradable polyurethanes, polyphosphazenes, linear and crosslinked poly(ether/ester)s, poly(epsilon-caprolactone) copolymers, poly(1,3-trimethylene carbonate) and their copolymers, poly(polyol sebacate)s, poly(diol-citrates) and poly(ester amide)s. The in vitro and in vivo degradation mechanisms and impact factors influencing degradation behaviors are discussed. In addition, the molecular designs, synthesis methods, structure properties, mechanical properties, biocompatibility and potential applications of these bioelastomers were also presented. PMID: 20057942 [PubMed - in process] | | |
| Microwave-assisted synthesis of triple-helical, collagen-mimetic lipopeptides.
January 9, 2010 at 6:29 AM
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| | Microwave-assisted synthesis of triple-helical, collagen-mimetic lipopeptides. Nat Protoc. 2010;5(1):39-50 Authors: Banerjee J, Hanson AJ, Muhonen WW, Shabb JB, Mallik S Collagen-mimetic peptides and lipopeptides are widely used as substrates for matrix degrading enzymes, as new biomaterials for tissue engineering, as drug delivery systems and so on. However, the preparation and subsequent purification of these peptides and their fatty-acid conjugates are really challenging. Herein, we report a rapid microwave-assisted, solid-phase synthetic protocol to prepare the fatty-acid conjugated, triple-helical peptides containing the cleavage site for the enzyme matrix metalloproteinase-9 (MMP-9). We employed a PEG-based resin as the solid support and the amino acids were protected with Fmoc- and tert-butyl groups. The amino acids were coupled at 50 degrees C (25 W of microwave power) for 5 min. The deprotection reactions were carried out at 75 degrees C (35 W of microwave power) for 3 min. Using this protocol, a peptide containing 23 amino acids was synthesized and then conjugated to stearic acid in 14 h. PMID: 20057380 [PubMed - in process] | | |
| A novel calcium phosphate ceramic-magnetic nanoparticle composite as a potential bone substitute.
January 9, 2010 at 6:29 AM
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| | A novel calcium phosphate ceramic-magnetic nanoparticle composite as a potential bone substitute. Biomed Mater. 2010 Jan 7;5(1):15001 Authors: Wu Y, Jiang W, Wen X, He B, Zeng X, Wang G, Gu Z A magnetic field has been applied to accelerate bone healing for a long time. In this study, in order to combine the bone repair capability of calcium phosphate (CaP) ceramics with the magnetic field, a novel CaP ceramic-magnetic nanoparticle (CaP-MNP) composite was fabricated through integrating the superparamagnetic nanoparticles into the CaP ceramics. Two kinds of CaP ceramics were chosen: hydroxyapatite (HA) and HA/tricalcium phosphate (65/35, HT). The samples were cultured with Ros17/2.8 and MG63 cells respectively in vitro to evaluate the cell proliferation and differentiation via MTT and alkaline phosphatase activity tests. In order to find the influence of the magnetic materials on the expression of the bone morphological protein (BMP), the samples composited with BMP-2 were implanted subcutaneously in the fasciae of rat back muscles for 30 days. Compared with ordinary CaP ceramics, the results indicated that the CaP-MNP composite had good biocompatibility! and was able to promote cell proliferation and differentiation significantly. The in vivo test showed that the expression of BMP-2 would be accelerated by HT composited with MNPs, and new bone-like tissue formation could be observed. Accordingly, it might be expected that this CaP-MNP composite could become a potential bone substitute or bone tissue engineering scaffold. PMID: 20057017 [PubMed - as supplied by publisher] | | | |
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