| Purpose:Clinical studies have shown that bone mesenchymal stem cells (BMSCs) transplantation after myocardial infarction (MI) profits the angiogenesis and cardiac function recovery. Due to the high and specific expression on endothelial cells of new blood vessels, integrin αvβ3has become the new monitoring target molecules of angiogenesis. The purpose of this study is to build a new type of molecular probe18F-FAl-NOTA-PRGD2which targets at αvβ3, and monitor the angiogenesis of MI area after treatment of BMSCs through PET imaging.Methods:One-step synthesis of18F-FAl-NOTA-PRGD2. BMSCs of SD-rat were isolated and cultured, then identified by osteogenic induction and adipogenic differentiation. Rats were randomly divided into treatment group and control group, which inject physiological saline or BMSCs at the edge of MI area. PET imaging was performed at1week and4week after modeling with probe18F-FAl-NOTA-PRGD2to observe angiogenesis after MI. SPECT imaging was performed the day before PET imaging. After PET imaging, autoradiography, biodistribution and immunofluorescence, HE staining were also performed to conform the PET scan results.Results:The total synthesis time was about25min and the yield was consistently between20-25%. The radiochemical purity was over97%; SPECT myocardial perfusion imaging shows the SD-rat MI modeling is successful; PET imaging shows the MI area organization of2groups have obvious tracer uptake. At1week after surgery, the ratio (infarted myocardium/normal myocardium) of the control group and the treatment group was3.01±0.03、3.77±0.16, there was a significant deference between2groups, p<0.05; at4week after surgery, obvious tracer uptake is still visible, but concentration degree are lower than1week, the ratio of the control group and the treatment group was2.86±0.13、3.51±0.05, there.was a significant deference between2groups, p<0.05. Autoradiography results are similar to PET imaging. At1week after surgery, the ratio of the control group and the treatment group was1.95±0.20,0.20±0.20, there was a significant deference between2groups, p<0.05; At4week after surgery, the ratio of the control group and the treatment group was1.70±0.07,0.07±0.06, there was a significant deference between2groups, p<0.05. BioD (biodistribution) shows that at1week, the tracer uptake of group BMSCs is higher than that of group NS (0.2229±0.003383%ID/g vs.0.1628±0.01205%ID/g,p<0.05); while at4week, the tracer uptake of group BMSCs is still higher than that of group NS (0.1907±0.013649%ID/g vs.0.1265±0.006341%ID/g, p<0.05), the result is similar to that of PET imaging and autoradiography.Conclusion:Preparation of this new type tracer18F-FAl-NOTA-PRGD2is simple and time is short. This tracer is stable with high specific activity. It can detect angiogenesis after bone marrow stem cells therapy for ischemic myocardium through PET imaging using18F-FAl-NOTA-PRGD2. There are9figures and29references in this paper. |
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