Cardiovascular diseases are a group of disorders of the circulatory system. However, the complexity of the etiology of these diseases and the involvement of many factors make understanding difficult. Among these factors, the microparticles (MPs) are membrane vesicles released from activated or apoptotic cells, detectable in the blood, even in healthy subjects, but the alteration of the level and phenotype is very often correlated with the severity of the pathology. Many works have also contributed to highlight the participation of MPs as vectors in the regulation of many cellular functions. This thesis studied the influence of MPs in two cardiovascular diseases, pulmonary arterial hypertension (PAH) and obstructive sleep apnea syndrome (OSA), with hypoxia as a common feature. We have established an alteration of circulating levels and some populations of MPs as well as a participation of MPs in the vascular dysfunction which occurred in PAH and OSA. This work contributes to understanding the role of MPs in the pathophysiological mechanisms involved in these pathologies.
