SERUM COMPLEMENT AND FAMILIAL COMBINED HYPERLIPIDEMIA

Familial combined hyperlipidemia (FCHL) is one of the most common inhe rited lipid disorders. Resistance of adipocytes to the effects of acyl ation stimulating protein (ASP) may contribute to ineffective triglyce ride synthesis and thereby prolonged postprandial lipemia and increase d fatty acid flux to the liver seen in FCHL patients. Interestingly, A SP is identical to C3a-desArg, fragment of the third component of comp lement. We examined the relationships between serum levels of compleme nt components C3 and C4 and markers of lipid and glucose metabolism in 11 large FCHL families (n = 53). Median serum C3 levels were 38% high er in affected compared to non-affected male FCHL family members (1.90 g/l vs. 1.38, P = 0.0027). The strongest correlations were observed b etween serum complement C3 and apolipoprotein B levels, reaching 0.77 in males. These relations were not confounded by obesity or impaired g lucose tolerance. In conclusion, serum levels of the main complement c omponents C3 and C4 correlated significantly with serum lipid levels. Further studies are needed to clarify the importance of disturbances i n the complement system on the pathogenesis of FCHL and other lipid di sorders. (C) 1997 Elsevier Science Ireland Ltd.