VLDL

Very low-density lipoprotein (VLDL) is a class of lipoprotein produced by the liver that transports endogenously synthesized triglycerides and cholesterol to peripheral tissues. VLDL particles are rich in triglycerides and contain cholesterol esters, phospholipids, and apolipoproteins, most notably apolipoprotein B-100, along with exchangeable apolipoproteins ApoC-II, ApoC-III, and ApoE.

Lipid transport and metabolism: VLDL is secreted into plasma by hepatocytes, where lipoprotein lipase (LPL) hydrolyzes triglycerides, releasing free fatty acids for uptake by tissues. As triglycerides are removed, VLDL is converted to intermediate-density lipoprotein (IDL), and further processing by hepatic lipase yields low-density lipoprotein (LDL). ApoE on remnants promotes hepatic clearance; ApoC-II activates LPL.

Regulation and clinical relevance: VLDL production rises with increased hepatic triglyceride synthesis, often in response to high carbohydrate intake, obesity, insulin resistance, or diabetes. Hypertriglyceridemia with elevated VLDL is associated with pancreatitis risk and is a component of metabolic syndrome. Genetic disorders such as familial combined hyperlipidemia and dysbetalipoproteinemia (remnant removal disease) affect VLDL metabolism.

Measurement and interpretation: VLDL-cholesterol is commonly estimated as triglycerides divided by 5 in fasting samples, though this approximation fails at very high triglycerides; direct measurement exists but is not routine. Clinically, VLDL-related triglyceride levels contribute to overall cardiovascular risk assessment alongside LDL and HDL measurements.