The big picture: ApoB (Apolipoprotein B) is a type of protein bound to every potentially atherogenic lipoprotein, which transports cholesterol and other substances through the bloodstream. These particles have the potential to breach arterial walls, contributing to vascular disease. Notably, just a small increase of 1 mg/dL in ApoB is linked to a 13% rise in the risk of cardiovascular mortality.

ApoB variants explained: ApoB manifests in two forms: ApoB-100, synthesized by the liver, and ApoB-48, derived from the small intestine. ApoB-100 plays a crucial role in maintaining the structural integrity of atherogenic lipoproteins such as LDL, VLDL, and Lp(a). The ApoB blood test measures the sum of ApoB-100 proteins, thus reflecting the total number of atherogenic lipoprotein particles circulating in the bloodstream.

Role in atherosclerosis: ApoB-containing lipoproteins, while essential for cholesterol transport in the bloodstream, can be detrimental in excess, leading to the formation of fatty plaques inside arterial walls. This condition, known as atherosclerosis, is a leading cause of cardiovascular disease. The particles penetrate the arterial lining, resulting in plaque buildup that narrows and hardens arteries, thus impeding blood flow. Such vascular damage and inflammation significantly increase the risk of serious cardiovascular events, like heart attacks and strokes.

ApoB vs LDL cholesterol: ApoB has emerged as a superior biomarker for cardiovascular risk compared to previous standard of LDL cholesterol. This is because it’s not just the cholesterol within LDL particles but the total number of ApoB-carrying particles that poses a greater risk by potentially damaging arterial walls. ApoB assessments encompass all atherogenic lipoproteins, such as LDL, VLDL, Lp(a), providing a more comprehensive risk evaluation. While ApoB levels typically align with LDL cholesterol, discrepancies can arise, making ApoB a more reliable indicator in such instances.