Small dense LDL (sdLDL)

Small dense LDL (sdLDL) is a subfraction of LDL particles characterised by reduced diameter (less than approximately 25.5 nm) and higher density compared with large buoyant LDL, arising primarily in states of hypertriglyceridaemia and insulin resistance through CETP-mediated triglyceride-for-cholesterol exchange. sdLDL particles are more atherogenic than large buoyant LDL for several reasons: they have lower affinity for the LDL receptor and therefore a longer plasma half-life, they penetrate the arterial intima more readily, they are more susceptible to oxidative modification, and they bind more avidly to proteoglycans in the subendothelial matrix. Elevated sdLDL concentration is independently associated with coronary artery disease and is a component of atherogenic dyslipidaemia — the lipid triad of elevated triglycerides, low HDL-C, and a predominance of sdLDL.