Mesenchymal Stromal Cell-derived Exosomes Attenuate Experimental Pulmonary Arterial Hypertension

Background: Pulmonary arterial Hypertension (PH) is a chronic disease that ultimately progresses to right ventricular failure and death. Until now, there is still a lack of effective treatment applied. The purpose of the present study was to observe the protective effect of Mesenchymal Stromal Cell-Derived Exosomes (MSC-EXO) against experimental Pulmonary arterial Hypertension (PH) and right ventricular failure. Methods: All the experimental rats received an intraperitoneal injection of 50 mg/kg monocrotaline to induce PH model. Three weeks after the model was successfully established, the cell Culture Media (CM) or MSC-EXO derived from human umbilical cord was administered daily via the tail vein. All animals were randomly divided into 4 groups: Control (saline-treated), MCT-PH, MCT-CM and MCT-EXO groups. Post-operation, hemodynamic data and index of right ventricular hypertrophy (RVHI) were recorded to evaluate the inhibition of MSC-EXO on MCT-induced PH. Histology, immunohistochemistry and western blot were used to analyze the effect of MSC-EXO against vascular remodeling and further reveal the mechanism. Results: In the present study, our results showed that MSC-EXO administration could significantly reduce the Right Ventricular Systolic Pressure (RVSP) and RVHI, suppress the pulmonary vascular remodeling and The Endothelial-Mesenchymal Transition (EndMT) process. Conclusion: Our results provided the firm information for a new method in the treatment of PH; the mechanism may be related to the inhibition of vascular remodeling and EndMT.