NON-GENETIC FACTORS MODIFY THE QUANTITATIVE GENETIC TRAIT LIPOPROTEIN (A) AND AFFECT ITS PATHOGENICITY

Lipoprotein(a) is an LDL-like lipoparticle having the distinctive multi-kringle apolipoprotein(a). Although the physiological roles of lipoprotein(a) have been somewhat elusive, its pathological effects, closely related to plasma concentrations, have been widely studied. Several variants of the LPA gene contribute to its differential expression, and to lipoprotein(a) levels and pathogenicity. Although most of the variations in lipoprotein(a) concentrations are under genetic control, a relationship between plasma levels, apolipoprotein(a) phenotypes, anthropometric and biochemical factors, and environmental-associated events has been reported in many studies. Study of transgenic animals, which bypasses the absence of lipoprotein(a) in common laboratory animals, is an excellent model to examine the function of increased plasma lipoprotein(a) in differing pathological conditions or in cases of dietary intervention. This chapter offers an overview of some of the non-genetic factors which have modest, albeit significant, effects on lipoprotein(a) levels, also assessing their possible interactions with specific apolipoprotein(a) genotypes. The effects of estrogenreplacement therapy and dietary interventions in the modulation of lipoprotein(a) levels, and the influence of age are evaluated, taking into account their implications in the atherogenic risk. Lastly, the controversial role of lipoprotein(a) as an acute phase reactant and, in particular, its possible beneficial role in surgical trauma are discussed