New Insights into the Key Role of Extracellular Vesicles in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. NAFLD, the hepatic manifestation of the metabolic syndrome, closely associates with insulin resistance, type 2 diabetes mellitus, obesity and cardiovascular disease. Until now, the specific factors involved in the progression of NAFLD from fatty liver to non-alcoholic steatohepatitis, cirrhosis and, ultimately hepatocellular carcinoma have not been totally elucidated. Also, patients have to face the lack of efficient or personalized treatments, as well as the absence of reliable diagnosis or staging methods beyond the highly invasive liver biopsy. In the last years, extracellular vesicles (VEs) are considered as potential biomarkers for the diagnosis many diseases including NAFLD. VEs are released by different cells types into the circulation and contain nucleic acids and proteins, among other components of their, that interact with surrounding or distant target cells, thereby triggering a plethora of responses. During NAFLD progression, several processes such as inflammation, fibrosis and angiogenesis, all related to MS-associated lipotoxicity, lead to VEs release by liver cells. In this review we will focus in the role of hepatocyte-derived VEs (Hep-VEs) and their interactions with non-parenchymal liver cells populations during NAFLD pathogenesis, as well as in their role as non-invasive biomarkers for disease diagnosis and progression. We will highlight the recent work currently available on VEs in the context of NAFLD, the current limitations and future directions for the implementation of VEs as biomarkers or targets of liver disease in the clinical setting.