LIPOPROTEIN (A) IN PATIENTS WITH HYPERLIPIDEMIA

Lipoprotein (a) [Lp(a)] is an atherogenic lipoprotein which is similar in structure to, but metabolically distinct from, LDL. Factors modulating plasma Lp(a) concentrations are poorly understood. We hypothesized that patients with hyperlipidaemia have elevated Lp(a) levels and determined the phenotype, concentration and distribution of Lp(a) in a group of hyperlipidaemic patients (n = 107) compared with a control group (n = 128). Lp(a) concentrations were significantly increased in the hyperlipidaemic patients (mean, 34 +/- 4 mg dL(-1). median, 19 mg dL(-1)) compared with the controls (20 +/- 3 mg dL(-1)); 9 mg dL(-1))) (P < 0.01). Interestingly, after dividing the patients into one group with elevated cholesterol (> 200 mg dL(-1)) (n = 44) and another group with elevated triglycerides (> 200 mg dL(-1)) (n = 51) we found that Lp(a) concentrations were 2.3-fold higher in the high cholesterol patients (mean, 45 +/- 5; median, 41 mg dL(-1)) compared to the high triglyceride subjects (20 +/- 4; 8 mg dL(-1)) (P < 0.01). Furthermore, a negative correlation between triglyceride and Lp(a) plasma concentrations was found in patients exhibiting triglyceride levels > 300 mg dL(-1) (r= -0.41, P = 0.04, n = 36) and with triglycerides > 400 mg dL(-1) (r= -0.52, P = 0.03, n = 17). These data indicate that plasma Lp(a) concentrations are elevated in hyperlipidaemia if the patients have high cholesterol levels, whereas Lp(a) is normal to low in patients with elevated triglycerides. The dominating lipid elevation in this condition and increased Lp(a) levels may contribute to the increased risk of premature coronary artery disease (CAD) in hyperlipidaemic patients.