Résumé
Abstract only Introduction: Although for a long time considered as simple cellular debris, extracellular vesicles (EVs) are now known to be involved in many pathophysiological processes such as thrombosis, autoimmune diseases and inflammation. Due to their diversity and presence in different tissues, EVs are considered important biomarkers and thus, their precise detection in various biological fluids is important to better understand all their different functional activities. The lymphatic system works in close collaboration with the cardiovascular system to preserve fluid balance throughout the body. Lymphatic vessels are present in almost all vascularized tissues, including the brain and the artery wall, and their role in these organ-related pathologies are under intense investigations. Hypothesis: Since lymphatic vessels are often perceived as "sewers", due to their role in removing interstitial fluid and waste products from peripheral tissues such as the artery wall, we herein want to qualitatively and quantitatively assess the presence of EVs in circulating lymph. Methods and Results: Using several approaches such as a Zetasizer Nano S, electron microscopy and flow cytometry analysis, we have detected and characterized EVs in lymph of healthy animals, and found that these EVs are inclusively derived from red blood cells, platelets and lymphatic endothelial cells. Analysis of lymph from atherosclerotic mice (Ldlr -/- ) confirmed the idea that EVs number and origin varies according to the pathological setting. Conclusion: Herein, we show for the first time that EVs are present in lymph and that their level and origin vary in atherosclerosis. Our work will be setting the stage to a better understanding of the mechanism underlying EV accumulation in peripheral tissues during inflammation, and to better control related diseases.