Lipideuptake

Lipideuptake is the process by which cells take up lipids from the extracellular space. Lipids include fatty acids, monoglycerides, cholesterol, and phospholipids derived from diet or circulating lipoproteins. Uptake supports energy production, membrane synthesis, and signaling.

In the intestine, dietary triglycerides are emulsified by bile acids and hydrolyzed by pancreatic lipase to free fatty acids and monoglycerides. These products form micelles and are absorbed by enterocytes via transport proteins such as fatty acid transport proteins (FATPs) and CD36, with cholesterol absorbed through NPC1L1. Inside enterocytes, fatty acids and monoglycerides are reassembled into triglycerides and packed into chylomicrons, which are released into the lymphatic system and then the bloodstream.

In peripheral tissues, lipoprotein lipase (LPL) on the endothelium of capillaries hydrolyzes triglycerides in circulating chylomicrons and VLDL, releasing free fatty acids that are taken up by cells through transporters such as CD36, FATP, and FABPpm. In adipose tissue, insulin stimulates LPL activity and promotes storage of fatty acids as triglycerides; in muscle, uptake supports fatty acid oxidation for energy.

Regulation and clinical relevance: Lipideuptake is modulated by hormonal signals (for example, insulin promotes storage in adipose tissue), nutritional state, and transcriptional regulators such as PPARs. Dysregulation of lipid uptake can contribute to metabolic disorders, including obesity, insulin resistance, and dyslipidemias, while impaired intestinal lipid absorption can lead to malabsorption syndromes.