Which lipid-lowering agent reduces hepatic VLDL secretion and is commonly used to treat dyslipidemia?

Which lipid-lowering agent reduces hepatic VLDL secretion and is commonly used to treat dyslipidemia?

• A. Statin
• B. Ezetimibe
• C. Fenofibrate
• D. Niacin

Answer: (D)

The key idea is lowering the liver’s production of VLDL to reduce triglyceride-rich lipoproteins in the blood. Niacin does this by cutting back the supply of fatty acids to the liver: it inhibits lipolysis in adipose tissue, so fewer free fatty acids reach the liver. With less substrate for triglyceride synthesis, the liver makes and secretes less VLDL. That drop in VLDL translates into lower circulating triglycerides and a downstream drop in LDL, since VLDL is the LDL precursor. Niacin also tends to raise HDL, but the main point here is its action on hepatic VLDL secretion. Other agents work through different primary mechanisms. A statin lowers cholesterol synthesis and increases LDL receptor activity, mainly reducing LDL rather than VLDL secretion. Ezetimibe blocks intestinal cholesterol absorption, primarily lowering LDL. Fenofibrate activates PPAR-alpha to boost fatty acid oxidation and increase lipoprotein lipase–mediated clearance, which reduces VLDL and TG mainly by enhancing clearance and metabolism rather than by a direct, primary suppression of hepatic VLDL production.

The key idea is lowering the liver’s production of VLDL to reduce triglyceride-rich lipoproteins in the blood. Niacin does this by cutting back the supply of fatty acids to the liver: it inhibits lipolysis in adipose tissue, so fewer free fatty acids reach the liver. With less substrate for triglyceride synthesis, the liver makes and secretes less VLDL. That drop in VLDL translates into lower circulating triglycerides and a downstream drop in LDL, since VLDL is the LDL precursor. Niacin also tends to raise HDL, but the main point here is its action on hepatic VLDL secretion.

Other agents work through different primary mechanisms. A statin lowers cholesterol synthesis and increases LDL receptor activity, mainly reducing LDL rather than VLDL secretion. Ezetimibe blocks intestinal cholesterol absorption, primarily lowering LDL. Fenofibrate activates PPAR-alpha to boost fatty acid oxidation and increase lipoprotein lipase–mediated clearance, which reduces VLDL and TG mainly by enhancing clearance and metabolism rather than by a direct, primary suppression of hepatic VLDL production.