Ectopic lipid accumulation in liver

Ectopic lipid accumulation in the liver refers to the abnormal storage of lipids—primarily triglycerides—within hepatocytes, which are not specialized for long-term fat storage. This phenomenon underlies hepatic steatosis and is central to nonalcoholic fatty liver disease (NAFLD). The process results from an imbalance between uptake/synthesis and oxidation/export of fatty acids in the liver. Mechanisms include increased delivery of free fatty acids from adipose tissue, enhanced de novo lipogenesis, reduced beta‐oxidation, and impaired export via very low-density lipoproteins. Chronic hepatic lipid overload disrupts normal metabolic signaling pathways and can impair insulin signaling through mechanisms such as diacylglycerol-mediated activation of protein kinase Cε or inflammatory signaling cascades involving toll-like receptor 4. These changes contribute significantly to systemic insulin resistance and increase risk for type 2 diabetes mellitus and cardiovascular diseases. While ectopic hepatic fat can be quantified by advanced imaging techniques like magnetic resonance spectroscopy, it does not represent a single molecular entity or therapeutic target but rather a pathological state resulting from dysregulated metabolism.

Other names

Hepatic steatosisLiver fat accumulationNonalcoholic fatty liver (when referring to the process, not the disease)Ectopic hepatic lipid deposition