| Objective To explore the therapeutic effects of intraperitoneal injection of arsenic trioxide in combination with autologous implantation of endothelial progenitor cells (EPC) from peripheral bloods on monocrotaline(MCT)-induced murine pulmonary arterial hypertension(PAH) and the possible acting mechanisms.The present study also tried to identify noninvasive biomarkers of endothelial turnover that could be used to identify congenital heart disease patients at risk of PAH.Methods 5 ml of peripheral blood was aspirated from the femoral artery of each Sprague-Dawley (SD) rat. Mononuclear cells (MNCs) were differentiated by Ficoll density gradient centrifugation and subcultured for 10 to 14 days in mixed endothelial growth medium. Meanwhile, momocrotaline was intraperitoneally injected to induce PAH. The rats were intravenously infused with cultured EPC derived from peripheral blood MNCs or EPC together with intraperitoneal injection of arsenic trioxide two weeks after the very beginning. E/A ratio of tricuspid valve was calculated from echocardiogram to evaluate the diastolic function of right ventricle (RV). The rats were euthanized 3 weeks after intervention. The mean pulmonary arterial pressure(mPAP) and right ventricular systolic pressure(RVSP) were invasively monitored. The ratio of right to left ventricular plus septal weight (RV/LV+IVS) was determined indicated as RV index. Haematoxylin and Eosin staining was performed to evaluate histological pathology. Immunohistochemistry assay was used to evaluate the microvessel density(MVD) aided by Factorâ…§. Tunnel staining was performed to determine the apoptosis ratio of pulmonary arteriolar smooth cells under laser confocal microscopy.Circulating CD34+CD133+ EPCs were quantified by flow cytometry(FCM) in peripheral blood samples from 34 clients (13 with PAH associated with congenital heart disease and 21 control patinets). The ability of adhesion and migration of EPC was evaluated and compared between patients with PAH and those in the healthy control group.Results mPAP and RVSP were significantly increased at day 14 after MCT injection compared with saline-treated control rats. Right ventricular hypertrophy as measured by the ratio of RV/(LV+IVS) weight was increased in animals receiving MCT alone. Administration of autologous EPC had prominent protective effects 3 weeks after intervention, significantly alliviating right ventricular hypertrophy and decreasing mPAP and RVSP. The impaired endothelium was replaced and MVD was noticeably densed. The diastolic function of RV was prominently recovered in the EPC infused animals. More prominent effects were observed in the animals reveiving intraperitoneal injection of arsenic trioxide in combination with EPC infusion.FCM indicated that the number and ability of adhesion and migration of peripheral EPC were significantly lower in patients with PAH than in the healthy control clients, with a negative correlation between the number and ability of adhesion and migration of EPC.Conclusion Intraperitoneal injection of arsenic trioxide in combination with autologous EPC implantation can better the diastolic function of RV in the setting of MCT-induced PAH, significantly reverse the PAH associated index, such as RV/(LV+IVS), mPAP and RVSP. The mechanism might lie in the repaired pulmonary arteriolar endothelium from EPC infusion and angiogenesis, and promotion of apoptosis of smooth cells from arsenic trioxide. The circulating EPC could be a valuable tool to define therapeutic individual strategies in congenital heart disease patients with PAH. |
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