Context: Lecithin:cholesterol acyltransferase (LCAT), which esterifies free cholesterol to cholesteryl esters, is required for normal plasma lipoprotein structure and is instrumental in high density lipoprotein (HDL) remodeling, but the relationship of variation in plasma LCAT activity with subclinical atherosclerosis is unclear.

Objectives: The aim of the study was to determine the effect of the metabolic syndrome (MetS) on plasma LCAT activity and its relationship with carotid artery intima media thickness (IMT).

Setting: The study was conducted at the vascular laboratory of a university medical center.

Methods: In 74 subjects with MetS and 90 subjects without MetS (National Cholesterol Education Program Adult Treatment Panel III criteria), mean carotid artery IMT, plasma lipids, LCAT activity (exogenous substrate method), high-sensitive C-reactive protein, and homeostasis model assessment insulin resistance (HOMA(ir)) were documented.

Results: IMT was greater (P = 0.01) and plasma LCAT activity was higher (P < 0.001) in subjects with MetS compared to subjects without MetS. Similar increases in IMT and LCAT were found in MetS subjects without type 2 diabetes mellitus. Multiple linear regression analysis demonstrated that plasma LCAT activity was independently and positively related to HOMA(ir), plasma triglycerides, non-HDL cholesterol, and HDL cholesterol (all P < 0.001). After adjustment for age and sex, IMT was positively associated with LCAT activity (P < 0.01), independently of the presence of MetS (or alternatively of plasma lipids), HOMA(ir), and high-sensitive C-reactive protein.

Conclusions: Plasma LCAT activity is elevated in MetS and may be a marker of subclinical atherosclerosis. Our findings do not support the contention that strategies to elevate LCAT are necessarily beneficial for cardioprotection.