Hypermetabolic State Drives Platelet Dysfunction in Human and Mouse Metabolic Dysfunction-Associated Steatotic Liver Disease

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a growing health concern given rising global prevalence, limited diagnostic and therapeutic tools, and strong association with cardiovascular disease. Platelets and oxidized phospholipids have been implicated in MASLD pathogenesis; however, the drivers and activities of platelets in MASLD remain overlooked. Methods: We conducted a cross-sectional study to determine platelet metabolic and functional states in MASLD and to investigate whether oxidized phospholipids, which accumulate during MASLD, contribute to platelet dysfunction. The study included age-matched individuals with simple steatosis (n=42), steatohepatitis (n=28), metabolic dysfunction-associated cirrhosis (n=16), and controls without steatosis (n=23). Platelet function and metabolism were characterized by flow cytometry and Seahorse analysis. In vivo markers of platelet activation and plasma oxidized low-density lipoprotein were quantified by ELISA. The causal relationship between oxidized phospholipids and the platelet phenotype was investigated by comparing Ldlr-/- mice fed an Amylin Liver NASH diet to Amylin Liver NASH-fed E06-scFv/Ldlr-/-, transgenic mice that express a natural antibody (E06) that neutralizes oxidized phospholipids. Results: We report that, since early MASLD in vivo markers of platelet secretion were elevated in plasma and platelets displayed a heightened metabolic activity. In advanced MASLD, associated with MASH and cirrhosis, platelets were refractory to G-protein-coupled receptor stimulation, but more responsive to GPVI stimulation, promoting a secretory and procoagulant phenotype. Platelet dysfunction correlated with increased platelet mitochondrial activity and with blood levels of oxidized low-density lipoprotein, a major source of oxidized lipids. Ex vivo, the oxidized phospholipid oxPAPC recapitulated the increased mitochondrial activity and functional reprogramming observed in MASH platelets. In a mouse model of MASLD, neutralization of oxidized phospholipids partially mitigated diet-induced platelet dysfunction and binding to liver macrophages. Conclusions: In MASLD, we observed heightened platelet metabolic activity and changes in platelet reactivity, providing the basis to target platelet dysfunction for preventing hepatic and extra-hepatic complications of MASLD. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05128253.