ABSTRACT
BACKGROUND:Transplantation of stem cells has a beneficial effect on myocardium revascularization and improving cardiac function after myocardial infarction, and HLA-G protein contributes to the formation and maintenance of the immune tolerance. OBJECTIVE:To investigate the transplantation effects of human umbilical cord mesenchymal stem cells at different gestational age with different HLA-G expression levels on myocardium revascularization after myocardial infarction in rabbits. METHODS:Thirty healthy New Zealand rabbits were selected and were randomly divided into human smal gestational age umbilical cord-derived mesenchymal stem cells transplantation group, human ful-term umbilical cord-derived mesenchymal stem cells transplantation group and control group. After the rabbits models of acute myocardial infarction had been established, the former two groups were infused different umbilical cord-derived human umbilical cord mesenchymal stem cells labeled with 5-bromo-2-deoxyuridine into the edge and center of myocardial infarct region by multipoint injection. Rabbits in the control group were subjected to an equal volume of serum-free culture medium. RESULTS AND CONCLUSION:Four weeks after celltransplantation, 5-bromo-2-deoxyuridine-positive cells were found surrounding the infarct site in both transplantation groups. Myocardial fibrosis and myocardial infarct size were significantly lower in both transplantation groups than those of the control group (P<0.05), and there was a significant difference between the two transplantation groups (P<0.01). The positive staining of factor VII indicated that capil ary density was increased significantly in the smal gestational age umbilical cord-derived mesenchymal stem cells transplantation group as compared with the ful-term umbilical cord-derived mesenchymal stem cells transplantation group (P<0.01), and a sstatistical difference was found between two transplantation groups and the control group (P<0.01). Transplantation of human umbilical cord mesenchymal stem cells with high HLA-G expression increases new capil ary vessels and improves myocardium revascularization. Al indicate that human smal gestational age umbilical cord mesenchymal stem cells have the potential to become the better source of cardiomyocytes transplantation.
ABSTRACT
BACKGROUND: Dysfunction of endothelial cells is independently associated with coronary atherosclerotic heart disease. Correlation of dysfunction of endothelial cells to restenosis after stent implantation is not yet clearly determined.OBJECTIVE: To evaluate the correlation of vascular endothelial dysfunction to restenosis after stent implantation. DESIGN, TIME AND SETTING: A case control study was performed at the Department of Cardiology and Department of Heart Ultrasound, Sichuan People's Hospital from March 2005 to January 2007.PARTICIPANTS: After review, coronary angiography showed that 11 patients who occurred restenosis at the lesion region after stent implantation were included in a restenosis group, and an additional 15 patients who did not develop in-stent restenosis were included in a control group. Patients in the following conditions were excluded: over 70 years old, histories of long-term smoking, diabetes mellitus, multivessel disease, long coronary lesion and chronic total occlusion, heart failure (Killip's class Ⅲ or above), severe hepatic and/or renal insufficiency.METHODS: High-resolution ultrasound was used to assess the percentage of flow-mediated dilatation of brachial artery. Differences in endothelial function were compared between both groups.MAIN OUTCOME MEASURES: Ultrasound parameter of the brachial artery in both groups; Partial correlation analysis on control variable including sex, age, blood lipid level, diseased region and stent type.RESULTS: No significant difference was found in basic diameter of brachial artery in both groups. During reactive hyperemia, inner diameter and its absolute variation of brachial artery were smaller in the restenosis group than in the control group (P<0.01). The percentage of brachial artery flow-mediated dilatation was lower in the restenosis group compared with the control group (P=0.013). The partial correlation coefficient between the percentage of flow-mediated dilatation of brachial artery and in-stent restenosis was 0.47 (P=0.04).CONCLUSION: The endothelial dysfunction significantly decreases in patients with restenosis compared with controls following stent implantation. There is a correlation between endothelial dysfunction and restenosis.