Search

Little is known about qualitative abnormalities of high-density lipoproteins (HDL) in systemic lupus erythematosus (SLE). We studied distribution and composition of HDL subclasses in 30 premenopausal women with uncomplicated SLE, and 18 controls matched for age and sex. Plasma and HDL lipids were determined by colorimetric enzymatic assays, HDL size distribution by native gradient polyacrylamide gel electrophoresis (PAGE) and apolipoproteins in HDL by sodium dodecyl sulphate denaturing PAGE. Compared with controls, SLE patients had significantly lower proportions of HDL2b (-14.7%) and higher proportions of HDL3b (+8.8%) and HDL3c (+23.3%). Cholesteryl ester (-18%) and apolipoprotein AI (-9%) were lower, whereas triglycerides (+32%) and apolipoprotein E (+27%) were higher in SLE HDL (P < 0.05; for all). In the whole population, stepwise regression analysis showed that only insulin concentrations (R2 = 0.327) and plasma total apo AI (R2 = 0.114) accounted independently to the variance in HDL size. This study shows that HDL distribution and composition are abnormal in non-complicated SLE patients. These HDL abnormalities have been reported to be associated to impaired atheroprotective properties of HDL and prevalence of coronary heart disease. Therefore, they may contribute to the premature atherosclerosis observed in young women with SLE. [ABSTRACT FROM AUTHOR]

Background : Lp(a) is a lipoparticle of unknown function mainly present in primates and humans. It consists of a low-density lipoprotein and apo(a), a polymorphic glycoprotein. Apo(a) shares sequence homology and fibrin binding with plasminogen, inhibiting its fibrinolytic properties. Lp(a) is considered a link between atherosclerosis and thrombosis. Marked inter-ethnic differences in Lp(a) concentration related to the genetic polymorphism of apo(a) have been reported in several populations. Aim : The study examined the structural and functional features of Lp(a) in three Native Mexican populations (Mayos, Mazahuas and Mayas) and in Mestizo subjects. Methods : We determined the plasma concentration of Lp(a) by immunonephelometry, apo(a) isoforms by Western blot, Lp(a) fibrin binding by immuno-enzymatic assay and short tandem repeat (STR) polymorphic marker genetic analysis by capillary electrophoresis. Results : Mestizos presented the less skewed distribution and the highest median Lp(a) concentration (13.25&ThickSpace;mg&ThickSpace;dL -1 ) relative to Mazahuas (8.2&ThickSpace;mg&ThickSpace;dL -1 ), Mayas (8.25&ThickSpace;mg&ThickSpace;dL -1 ) and Mayos (6.5&ThickSpace;mg&ThickSpace;dL -1 ). Phenotype distribution was different in Mayas and Mazahuas as compared with the Mestizo group. The higher Lp(a) fibrin-binding capacity was found in the Maya population. There was an inverse relationship between the size of apo(a) polymorphs and both Lp(a) levels and Lp(a) fibrin binding. Conclusion : There is evidence of significative differences in Lp(a) plasma concentration and phenotype distribution in the Native Mexican and the Mestizo group. [ABSTRACT FROM AUTHOR]