心肌细胞凋亡小分子探针PET显像研究

Cardiomyocyte apoptosis is a continuous process which results in a large loss of functional cardiomyocytes and play a causal role in the development and progression of heart failure. The noninvasive imaging of cardiomyocyte apoptosis can detect the location and size of cardiomyocyte apoptosis in early stage and offer great benefit in determining the extent of myocardial damage and monitoring the anti-apoptotic therapies. Currently, there is no effective imaging agent used to detect cardiomyocyte apoptosis.Targeting the phosphatidylserine (PS) which is on the surface of dying cell, we designed and synthesized novel 18F labelled Zn2+-dipicolylamine(DPA) analogs 18F-FB-DPAZn2 for PET imaging of cardiomyocyte apoptosis in early stage, in order to get the clear pictures. We detect cardiomyocyte apoptosis in the levels of cell, tissue and animal by using primary cardiomyocyte culture, heart tissue alice and heart failure model. PET imaging of cardiomyocyte apoptosis is compared with other techniques, such as fluorescent imaging, flow cytometry and the terminal dUTP nick-end labeling (TUNEL) assay in vitro. Ultimately, we will assess the specificity and sensibility of the Zn2+-DPA analogs PET imaging, and make efforts to the utilization of noninvasive detection of cardiomyocyte apoptosis in clinical practice in the future.

持续的心肌细胞凋亡会导致有功能的心肌细胞大量丧失，与心力衰竭的发生发展密切相关。无创心肌细胞凋亡显像可以早期识别这些凋亡细胞，确定凋亡的部位和范围，有助于判断心肌损伤程度，评价抗凋亡治疗效果。目前的细胞凋亡显像剂难以实现快速清晰的心肌显像。我们以早期凋亡细胞的膜表面标志物磷脂酰丝氨酸（PS）为靶标，设计合成了新型氟标记小分子Zn2+-DPA类似物18F-FB-DPAZn2，用于心肌细胞凋亡PET显像研究，以实现心肌细胞凋亡的清晰显像。通过原代心肌细胞培养、心肌组织切片和建立心力衰竭大鼠模型，从细胞、组织和整体三个层次进行心肌细胞凋亡显像，对比免疫荧光、流式细胞仪、TUNEL、PET等不同检测方法的凋亡显像效果，评价心肌细胞凋亡PET显像的特异性和敏感性。可望将这种无创心肌细胞凋亡显像技术推广应用于临床。

心肌细胞凋亡在心力衰竭的发生发展中起了重要作用，急需研发新的活体心肌细胞凋亡监测技术，为此，我们以凋亡细胞膜表面标志物磷脂酰丝氨酸（PS）为靶标，设计合成了新型氟标记小分子Zn2+-DPA类似物18F-FP-DPAZn2，评价其在大鼠心肌细胞凋亡PET显像中的应用。通过与TUNEL、蛋白印记检测方法对比研究发现，体外DPAZn2免疫荧光可用于心肌细胞凋亡显像；体内[18F]FP-DPAZn2 PET显像结果显示，在注射60分钟后心梗大鼠的[18F]FP-DPAZn2摄取值明显高于正常大鼠，其显像部位与体外免疫组化结果一致。作为一种新的无创显像技术，[18F]FP-DPAZn2 PET显像能够进行心肌细胞凋亡显像，但其心肌细胞摄取率有待提高，以便今后应用于临床。