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 modula ting plasma Lp(a) concentrations are poorly understood. We hypothesize d that patients with hyperlipidaemia have elevated Lp(a) levels and de termined the phenotype, concentration and distribution of Lp(a) in a g roup of hyperlipidaemic patients (n = 107) compared with a control gro up (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 wi th elevated cholesterol (> 200 mg dL(-1)) (n = 44) and another group w ith elevated triglycerides (> 200 mg dL(-1)) (n = 51) we found that Lp (a) concentrations were 2.3-fold higher in the high cholesterol patien ts (mean, 45 +/- 5; median, 41 mg dL(-1)) compared to the high triglyc eride subjects (20 +/- 4; 8 mg dL(-1)) (P < 0.01). Furthermore, a nega tive 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) conce ntrations are elevated in hyperlipidaemia if the patients have high ch olesterol levels, whereas Lp(a) is normal to low in patients with elev ated triglycerides. The dominating lipid elevation in this condition a nd increased Lp(a) levels may contribute to the increased risk of prem ature coronary artery disease (CAD) in hyperlipidaemic patients.