| Background:Since1966, Ross first application of allograft aortic valved treatment of patients with pulmonary atresia after the success of the development of antibiotic sterilization, controlled cooling, deep hypothermic preservation, and promote the valved vascular (valved homograft conduit that, VHC widely used) in cardiac surgery. With valved vascular structures naturally, the center of blood flow and anti-reflux, low immunity, less thrombosis, features, easy attachment of bacteria and other complex congenital heart disease, reconstruction of the right (left) ventricular outflow tract of biological materials.Clinically often encounter the same kind of valve degradation due to intrinsic abnormalities. This does not necessarily lead to valve dysfunction. Early decline of the same kind of valve implantation in young patients can be seen, the structural decline may have immunological basis. The valve between the donor and recipient major histocompatibility complex antigen matching test, and patients are not routinely receiving immunosuppressive therapy. Postoperative regurgitation, stenosis, and immune rejection occur, lead to a pipeline of early loss of power, need to double or multiple surgeries to replace the VHC. VHC in children showed shorter than the adult life of the poor durability characteristics, allogeneic vascular grafts can also lead to the calcification response of the host organism, the end result caused by graft stenosis and occlusion, which is the success of allogeneic vascular grafts a major obstacle. Reduce allogeneic blood vessel calcification in a new research direction. Vascular calcification process in the past was considered a passive process, and the natural aging and apoptosis. Recent studies suggest that it is an active cells involved in the regulation process. Extracellular calmodulin (including MGP and fetuin-A) is a strong inhibitor of calcium and phosphorus deposition. Under normal circumstances, the aorta and the coronary artery wall and early intimal fibrosis (the formation of atherosclerotic plaques) MGP expression, but in the artery atherosclerosis sclerosing injury, especially in lipid-rich plaques and calcified areas around the expression increased significantly.Could be detected in the specimens of each calcium deposition of MGP, especially in the area of microcalcifications. Immunohistochemical study using anti-human MGP monoclonal antibody staining of atherosclerotic damage of arterial wall and found that the aggregation of local large number of MGP. This shows that MGP is effects of factors inhibit artery calcification. Allogeneic vascular grafts must be pretreated to eliminate alloantigens on blood vessels. Reduce allograft vascular immune calcification, such as alcohol, formaldehyde, glycerol immersion; glutaraldehyde (glutaraldehyde, GA), poly-epoxy compounds (polyepoxycompound, PC) cross-linking; deep-frozen, lyophilized and radiation, penicillin and streptomycin in vitro pretreatment, vitrification method, the lining of mesothelial cells in vivo. Domestic and foreign scholars have done a lot to reduce allograft vascular resistance to calcification.Geneic vascular endothelium from the epithelial cells lining the body for more ideal way. Worked out better storage and handling of allograft vascular, as autologous blood vessels to be used, has very important significance. The combination of these various aspects, the autologous vascular endothelial cells cultured in vitro grown in the freeze-dried irradiated allogeneic vascular calcification of the allograft vascular grafts may reduce its clinical use to show a bright future. With genetic engineering techniques in tissue engineering applications in recent years, is expected by recombinant DNA technology vascular endothelial cells grown genetically modified, not only reduce the calcification of the problem, but also by changing the level of anticoagulant and procoagulant gene expression. Thereby enhancing the clotting activity of endothelial cell, will provide a more desirable approach. Another method is the same kind of organization with cyclosporine pretreatment, which had earlier applied to the dog of the same kind of vein, the approach can improve graft survival, scanning electron microscopy also found to alleviate degeneration. Cyclosporine is a highly effective immunosuppressive agents, applied to the individual valve replacement in clinical patients because the drug has serious adverse events generally advocated caution after the valve transplantation. Has been a lot of data show the same kind of flap, the early use of immunosuppressants with anti-calcification mechanism is inhibition of the early immune rejection after transplantation, thereby reducing the endothelial cells and smooth muscle cells by the immune attack and protect endothelial cells and smooth muscle cells. Augelli and other non-cyclosporine-treated dogs underwent transplantation of the same kind of vein application were observed and found that cyclosporine dog graft retention rate. Weeks Jiangqiao homemade cyclosporine A (CsA) composite renal perfusion fluid on the transplanted kidney perfusion, and observe the protective effect on renal ischemia-reperfusion injury, results show that the experimental group, serum BUN and Cr values were significantly lower (group A and group B), prove to have a protective effect of CsA on renal transplantation.Vascular calcification process in the past was considered a passive process, and the natural aging and apoptosis. Recent studies suggest that it is an active cells involved in the regulation process. Extracellular calmodulin (including MGP and fetuin-A) is a strong inhibitor of calcium and phosphorus deposition. Under normal circumstances, the aorta and the coronary artery wall and early intimal fibrosis (the formation of atherosclerotic plaques) MGP expression, but in the artery atherosclerosis sclerosing injury, especially in lipid-rich plaques and calcified areas around the expression increased significantly.Could be detected in the specimens of each calcium deposition of MGP, especially in the area of microcalcifications. Immunohistochemical study using anti-human MGP monoclonal antibody staining of atherosclerotic damage of arterial wall and found that the aggregation of local large number of MGP. This shows that MGP is a strong local effects of factors inhibit artery calcification.Therefore, the PCR detection of cyclosporine treatment after valved vascular matrix Gla protein (Matrix Gla Protein, of MGP) expression levels can understand the calcification reaction, its intensity evaluation. Currently no control follow-up study reported in the literature about the same kind of valve calcification affect cyclosporine pretreatment.Objective:To study the conduit transplantation cyclosporine pretreatment, glucose metabolism, immune response, transplant vascular calcium content and expression of MGP mRNA in the grafts of cyclosporine pretreatment with the protective effect of flap vascular grafts.Methods:White rabbits were randomly divided into two groups50,weight 2.50-3.50Kg.The left internal carotid artery (donor transplantation with aortic valve received cyclosporine pretreatment) as treatment group, the right common carotidartery (transplantation of donor aortic valved received cyclosporine pretreatment) control group. Transplant specimen was cut in2,4,8andl2weeks after transplantation, light microscopy and electron microscopy, determination of blood glucose metabolism measured by flow cytometry of CD25immunohis to chemical determination of expression of CD40,Determination of calcium content by RT-PCR analysis of MGP mRNA in protein.Results:1. Morphology:The experimental group of endothelial cell shedding and smooth muscle cell calcification compared with the control group light.2. Immuneresponse trends:Experimental groups:2to4weeks of CD25after transplantation of CD40expressionlevel was significantly lower than the control group (P＜0.01), but no significant difference between8and12weeks after transplantation, the expression level of the control group(P＞0.05).3.Trend of calcium content:Experimental group2,4,8andl2after transplantation, the calcium content of four different time points in weeks was significantly lower than control group(P＜0.01).4.Matrix Gla Protein(MGP)mRNA expression:2and4weeks of MGP mRNA levels gradually increased after transplantation.8and12weeks after transplantation levels began to decline. Showing dynamic changes in the first and then decreased.Conclusion:1.Cyclosporine pretreatment with aortic valve can improve graft patency rate, reduce thrombus formation, vascular endothelial cells to change to lighter.2.The immuno suppressive agents can reduce calcium content of graft, anti-calcification mechanism lies in protection of valved homograft aortic endothelial cells and smooth muscle cells.3.Valved vascular largrafts and graft calcium content is proportional to the level of immune rejection, but reinforce each other, influence each other.4.MGP mRNA level of dynamic changes is likely to inhibit the phenotypic change and proliferation of vascular smooth cells with cyclosporine. |
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