Biomarker des Lipoproteinstoffwechsels

Summary Biomarkers of lipoprotein metabolism The lipid status (total, HDL and LDL cholesterol [HDL-C and LDL-C], as well as triglycerides) is a key tool in estimating cardiovascular risk and defin ing indications and target values for lipid-lowering treatments. Due to the inaccuracy and method-dependency of HDL-C and LDL-C measurements, varying risk categories are determined for up to 20% of the population, depending upon the method used. Replacing HDL-C and LDL-C with apolipoproteins (apo) A-I and B does not signific antly improve the prediction of either car dio vascular risk or therapy success. Taking into account LDL and HDL subclasses does not improve risk prediction either. HDL and LDL particle numbers (HDL-P, LDL-P) exhibit better prediction potential. Combining LDL-C with ApoB, non-HDL-C, or LDL-P seems to improve risk prediction, whereby measuring non-HDL-C in addition is most cost-effective. The functionality of HDL is an interesting concept for the discovery of new HDL biomarkers. The bioassays used help in discovering proteins and lipids, as well as their modific ations, which can be employed in developing standardised quantitative assays that must be validated clinically and epidemiologically. Despite pathogenic relevance, lipoprotein(a) ( Lp[a]) only marginally improves risk stratifi cation using standard risk factors. The cut-off is also disputed: 300 mg/l vs 500 mg/l (= 80th percentiles) according to standard and more recent recommendations, respectively. The activity and concentration of lipoprotein-associated phospholipase A2 (LpPLA2) constitute relevant risk factors for athero sclerosis. Nonetheless, too little research has been conducted as to whether LpPLA2 improves risk prediction as c ompared to standard risk factors. Routine LpPLA2 measurement thus appears inappropriate. The increased clinical use of Lp(a) and LpPLA2 assays depends upon the effectiveness of new therapies directed against these proteins.