Purpose of review: To summarize recent studies that shed more light on possible mechanisms by which ectopic lipid storage affects organ function.
Recent findings: Although ectopic lipids have been considered as biomarkers of lipotoxicity, adaptation of metabolic fluxes and of mitochondrial function seem to be more important than actual cellular fat contents in liver and muscle. Diabetic and obese humans have elevated myocardial lipid contents, which are associated with mitochondrial and contractile dysfunction and could even precede the development of heart failure. Although pancreatic fat content is negatively associated with insulin secretion, [beta]-cell triglycerides are not easily accessible to measurement in humans rendering their role for [beta]-cell function unclear. New approaches to quantify energy metabolism in various organs could help to identify novel biomarkers of organ function in humans.
Summary: Dietary intake of high-caloric high-fat diets and sedentary lifestyle lead to increased storage of triglycerides not only in adipose tissue but also ectopically in other tissues. Intracellular lipid contents in skeletal muscle and liver have been related to insulin resistance and inflammatory processes. Myocardial fat is increased in heart failure, whereas pancreatic fat could relate to insulin secretion.