0229 : Aerobic exercise training modulates microparticles miRNAs: link to improved endothelial function and regulation of inflammation?

Exercise training is known to stimulate vascular function and remodeling in a shear stress and inflammation dependent manner. Microparticles (MPs) released from vascular cells in response to shear stress, play a role in cell-cell crosstalk through carrying bioactive molecules such as miRNAs. Thus, the aim of our study was to explore whether exercise training impacts vascular wall cells and contributes to vascular function improvement through the modulation of inflammation molecules release. Therefore, we investigated the presence in MPs of 9 inflammation-regulatory miRNAs. A group of sedentary women (n=6, BMI 2 ) recruited at F. Hached Hospital (Sousse, Tunisia) was enrolled in an 8-weeks training program. Vascular function was assessed by Laser Doppler Flowmetry, oxidant stress and systemic inflammatory marker (CRPus) and selected circulating cytokines were measured. Furthermore, before and after exercise training, circulating MPs quantification by flow cytometry and miRNAs content by real-time PCR, were realized. While exercise training improved significantly the endothelial-dependent vasorelaxation, decreased systemic inflammation and modified the profile of circulating cytokines, circulating MPs level and oxidant stress remained unchanged. The miRNAs profile revealed that 1/ miR155 and miR302a were not detected in MPs neither before nor after training program; 2/ miR21, miR150, miR320a, miR146a, miR124a, miR126 and miR223 were expressed in circulating MPs of sedentary women; and 3/ after training program, a significant increase of miR21, miR146a, miR124a, miR150 and miR223 content was observed while miR126 and miR223 remained unchanged. Our results highlight the role of MPs as vehicle for miRNAs and the importance of inflammation-regulatory miRNAs as effectors in the vascular wall in order to generate an optimal vascular function and to control inflammation. The author hereby declares no conflict of interest