| In 1954, the vascular prostheses were manufacture which the development of vascular surgery was accelerated. The prostheses replacing the big-caliber artery which got success, but the results of the middle or small-caliber artery and veins replaced were not satisfaction because the absence of endothelial cells of prostheses. Endothelial cells play an important role in preventing thrombosis, maintaining vessel patency, and inhibiting prosthetic hyperplasia. Seeding endothelial cells to inner surface of prostheses was the aim of biologic prostheses, but the absence of seeding cells interforenced the improvement of biologic prostheses. The few quantity of endothelial cells and the great invasion of the surgical methods which got the endothelial cells were not adapted forclinic. It has been proposed that hematopietic and endothelial cells are derived from a common cell, the hemangioblast, which express the CD34 antigen and has high proliferation. Bone marrow contains these cells. A recent in vitro study has shown that CD34+ cells can differentiate into endothelial cells in vascular endothelial growth factor(VEGF).In study, CD34+ cells were isolated from bone marrow of carine by an immune magnetic cell sorting system and differentiated into endothelial cells with VEGF combinations in a liquid culture system. Seeding the cells to PTFE prostheses which implanted the abdominal artery and inferior vena cava. At 6,8w, prostheses were harvested and detected by immunohistochemistry and electron microscope to understand the patency and endothelialization of prostheses to solved the seeding cells of biologic prostheses. 1 MethodsFifteen healthy adult mongrel canine were used (the group of experiment 12, the group of control 3). The dogs were anesthetized and bone marrow was aspirated and mixed with heparin. The mononuclera cells were Ficoll separated from bone marrow and CD34+ cells were further separated by an immune magnetic cell sorting system. Flow cytometer assay the purity of CD34+ cells. CD34+ cells differentiated into endothelial cells which were evaluated by immunocytochemistry and transmission electron microscopewith VEGF combinations in IMDM liquid culture system. Seeding the cells to PTFE prostheses which implanted the abdominal artery and inferior vena cava. At 6 , 8w, prostheses were harvested and detected by immunohistochemistry and scanning electron microscope to demonstrated the patency rate and endothelialization of prostheses to solved the seeding cells of biologic prostheses. 2 Results(1) Flow cytometer: The average number of the isolated CD34+ cells was 41.84+3.65%.(2) Endothelial cells growth and identificationInverted phase contrast microscope. The CD34+ cells derived from bone marrow were round shape, large of CD34+ cells pasted wall at 24-48h cultivation, conver round to oval cells at 3-4d, formation cytocolony at 5-6 d. Endothelial cells increased to the highest level at the 14th d . They present polygonal and arrange like pavementing stones under the microscope.Immunocytochemistry: At 14d, immunostaining of endothelial cells was positive for CD31, factor VIII in culture.Transmission electron microscope: In culture cells, Weibel-Palade bodies were found within the cytoplasm.(3) Seeding endothelial cells to prosthesesScanning electron microscopy: The innermost luminal layer was composed of flat cells, and the arragement of the cells were not tropism. (4) Gross examination: graft patency9 grafts were harvested at 6 weeks ( 2 grafts in abdominal aorta artery, 4 grafts in inferior vena cava and 3 grafts were controls), 6 grafts were harvested at 8 weeks (2 grafts in abdominal aorta artery, 4 grafts in inferior vena cava). A smooth flow surface was found in the opened segment in graft. One graft (6 weeks, in the inferior vena cava) was about stenosis of 60%, one graft ( 8 weeks, in the inferior vena cava) was occlusion. In the controls, three grafts were harvested at 6 weeks, 2 (in the inferior vena cava) of three grafts were occlusion, 1 graft... |
PDF Full Text Request