Background :~Obstructive Sleep Apnea Syndrome (OSAS) is one of the most common chronic diseases associated with cardiovascular and metabolic comorbidities (high blood pressure, type 2 diabetes, obesity and non-alcoholic fatty liver disease) that make it a prognosis.~These comorbidities are associated with a change in intestinal microbial ecology. In most cases, there is a reduction in bacterial genetic diversity and more or less specific signatures of cardiovascular and metabolic diseases which make it possible to envisage personalized and innovative therapeutic treatments.~In animals exposed to intermittent hypoxia, there is a local hypoxia that increases intestinal permeability, produces a reduction in microbial diversity, and favors microbial species that cause the secretion of pro-inflammatory factors.~Continuous Positive Airway Pressure (CPAP) is the gold standard for OSAS treatment. Its effect on the gut microbiota has never been evaluated.~The data will be totally original in the field. The impact of this study can be major in allowing to propose pre/probiotics or drug treatments modulating intestinal dysbiosis during OSAS, combined or not with CPAP.~Objective:~The principal objective of the study is to compare gut microbiota changes (diversity and composition : relative abundance of different phyla, genera, families, alpha and beta diversity...) after 3 months of effective CPAP versus 3 months of placebo (nasal dilators), in patients with Obstructive Sleep Apnea Syndrome.~The second objectives~Methods :~OSAS patients (with AHI > 30 / hour) will be screened in EFCR Service, Pneumology Department or Sleep Laboratory and proposed the study. If eligible they will be then followed over 3 months with 2 visits (inclusion visit at J0 and follow-up visit at 3 months). After the inclusion visit (J0) OSAS patients will be randomized for their treatment into CPAP group (effective CPAP treatment) or nasal dilators group (placebo treatment) for 3 months.~The same assessments will be carried out at J0 and 3 months.~Healthy volunteers (with no OSAS) will be the control group. They will be recruited by ad. They will carry out the assessments of inclusion visit (J0) only and compared then to the group of OSAS patients.
Obstructive Sleep Apnea Syndrome (OSA) is one of the most common chronic diseases and is associated with prognostic cardiovascular and metabolic co-morbidities. OSAS is the recurrence of complete (apnea) or partial (hypopnea) collapse of the upper airway during sleep resulting in sleep fragmentation and chronic intermittent hypoxia (ICH) which are the major determinants of cardiovascular and metabolic complications including type 2 diabetes, obesity and non-alcoholic fatty liver. These comorbidities are associated with a change in intestinal microbial ecology. In most cases, there is a reduction in bacterial genetic diversity and more or less specific signatures of cardiovascular and metabolic diseases, making it possible to envisage personalized and innovative therapeutic treatments. In animals exposed to intermittent hypoxia, there is local hypoxia that increases intestinal permeability, produces a reduction in microbiota diversity and favors microbial species that are at the origin of pro-inflammatory factors. Continuous Positive Airway Pressure (CPAP) is the standard treatment for OSA. Its effect on the intestinal microbiota has not yet been evaluated.