Evaluation Of Stem Cell Transplantation On Myocardial Infarction By Microbubbles Contrast Agents And CD34

Objective: Investigate the effects of stem cell transplantation on angiogenesis in acute myocardial infarction（AMI） model of rabbit by CD34-targeted microbubble contrast agents and parametric quantification （PQ） via its non-invasion evaluation. Methods: Prepared a CD34-targeted microbubble untrasound contrast agnents. Random-ly assigned eighty （80） New Zealand white rabbits into 1 Control Group （20 rabbits） and 3 Experimental Groups （each group including 20 rabbits）: Single Transplantation Group （T Group）, Transplantation+Common Contrast agents Group （T+C Group）, and Transplantation+Targeted Contrast agents （T+T Group）; the AMI model was established by ligating the left ventricular branch （LVB） of coronary artery. Each rabbit in the experimental groups received autologous stem cell transplantation 2w after ligation, and rabbits in the T+C Group and T+T Group were subjected to myocardial contrast echocardiography （MCE）; then compared myocardial function, haemodynamics, myocardial perfusion parameters （A,βand A×βvalues） and derived peak intensity （DPI）, time to peak （TP）, area under the curve （AUC）, time of starting myocardial visualization, time of complete myocardial visualization, and washout time （WT） before and after stem cell transplantation between the two groups used contrast agents. Then animals were sacrificed in 4 weeks after stem cell transplantation; determined microvessel density （MVD） by CD34 antibody immunohistochemistry, and carry out correlation comparison of it and the above-mentioned various indexes. In the Control Group, the above indexes were determined by injecting common microbubble contrast agents in 3 d and 6 w after AMI. Results: 1) In 4w after transplantation, BMSCs labled by Brdu were verified survival by immunohistochemistry; 2) In 4w after transplantation, ejection fraction （EF）, left ventricular end-diastolic dimension （LVEDD）, left ventricular systolic pressure （LVSP）, rate of rise of left ventricular pressure （±dp/dt max）, left ventricular end-diastolic pressure （LVEDP） were all ameliorated than before transplanta-tion; 3) Compared to before stem cell transplantation, the perfusion scores of T+C Group and T+T Group were increased than before transplantation and the Control Group; 4) A,βand A×βvalues of T+C Group （2.78±0.74 Vs 2.04±0.96, 0.91±0.24 Vs 0.20±0.17, 2.54±0.24 Vs 0.29±0.16）and T+T Group （2.93±0.50 Vs 2.13±0.68, 1.17±0.24 Vs 0.22±0.16, 5.69±0.39 Vs 0.36±0.23）were increased than those prior to stem cell transplantation （P<0.01）, moreover, the changes in those indexes in the T+T Group were more obvious than those in the T+C Group and Control Group （P<0.05）; 5) In T+C and T+T Groups, DPI and AUC（4.68±0.55、6.89±0.38 Vs 2.90±0.04、2.46±1.09, 254.45±41.65, 491.24±25.74 Vs 112.72±35.53, 132.68±32.60） were increased than those prior to transplantation, TP was decreased（2.66±0.33 Vs 4.31±0.12, 1.44±0.28 Vs 4.17±0.36）, WT was increased（7.45±1.32 Vs 4.90±0.75, 10.94±0.95 Vs 4.98±1.01）, and the time of starting myocardial visualization and the time of complete myocardial visualization were decreased （40.01±13.12, 39.97±20.11 Vs 64.61±13.46, 52.66±20.24, 118.23±30.22, 112.09±23.05 Vs 134.61±42.02, 145.26±35.43）; moreover, the changes in those indexes in the T+T Group were more obvious than those in the T+C Group （P<0.05）, and there were significant differences compared with the Control Group （P<0.05）. 6) After transplantation, MVDs in the three experimental groups were increased compared with those of the Controlled Group （10.02±8.12） （P<0.01）; MVDs in the T+T Group （63.93±15.89） and the T+C Group（42.18±13.54） were increased more obviously than in the T Group （28.61±11.57） （P<0.05）. 7) The correlation and regression analyses between MVD and observational contrast agents indexes in T+C group and T+T group were compared respectively. A×βvalue, DPI, AUC, and WT in the T+C Group was correlated with MVD （r=0.551, 0.662, 0.508, 0.658, P<0.05 in all those cases）; the various variables （β, A×βvalue, DPI, TP, AUC, Time of Complete Myocardial Visulization, and WT） in the T+T Group were of the highest correlation with MVD （r=0.767, 0.894, 0.819,-0.651, 0.743,-0.650, 0.898, P<0.05 in all those cases）; while WT （X₁） and A×β（X₂） as well as MVD （Y） were included to establish the following regression equation: Y=-139.066+8.510X₁ +19.360X₂, （R=0.508, 0.488, P<0.05）. Conclusion: Stem cell transplantation with CD34-targeted microbubble may increase therapeutic effects via angiogenesis in AMI rabbits, PQ and CD34-targeted microbubble contrast agents probably provides some value in invasive evaluation of angiogenesis after stem cell transplantation.