chylomicronidesare

Chylomicronides are lipoprotein particles formed in the enterocytes of the small intestine during the digestion and absorption of dietary fats. They are the body's main means of transporting dietary triglycerides and cholesterol esters to peripheral tissues. The core of chylomicronides is rich in triglycerides and cholesterol esters, surrounded by a phospholipid and cholesterol surface with apolipoproteins such as B-48, C-II, and E. Apolipoprotein B-48 is essential for assembly and secretion, while ApoC-II and ApoE serve functional roles after release into circulation.

Chylomicronides are assembled in the enterocyte endoplasmic reticulum with the help of microsomal triglyceride transfer protein (MTP) and are secreted into the intestinal lymphatic system as chyle. They drain into the bloodstream via the thoracic duct and are transported to tissues throughout the body. In capillaries, endothelial lipoprotein lipase (LPL) hydrolyzes the triglycerides within chylomicronides, releasing free fatty acids for uptake by adipose tissue and muscle. This lipolysis converts chylomicronides into smaller, denser remnants enriched in cholesterol esters. The hepatic uptake of these remnants primarily occurs through receptors that recognize ApoE, integrating dietary lipid clearance with liver metabolism.

Clinical relevance includes postprandial lipid dynamics and disorders of chylomicronide metabolism. Genetic defects affecting LPL, ApoC-II, ApoE, or related components can cause familial chylomicronemia or severe hypertriglyceridemia, increasing the risk of pancreatitis. Chylomicronide metabolism is, therefore, a key link between dietary fat absorption, energy distribution, and lipid homeostasis.