The role of lipoprotein (a) in pregnancies complicated by pre-eclampsia.

Endothelial cell dysfunction is a key feature of the pathogenesis of pre-eclampsia. The cause of the endothelial cell injury is probably multifactorial, but poor placenta perfusion plays a major role. In pre-eclampsia, characteristic pathological lesions in the placenta are fibrin deposits, acute atherosis and thrombosis. The similarity between the lesions of pre-eclampsia and atherosclerosis has led to speculations of a common pathophysiological pathway. An abnormal lipid profile is known to be strongly associated with atherosclerotic cardiovascular disease and has a direct effect on endothelial function. Abnormal lipid metabolism seems important in the pathogenesis of pre-eclampsia too. An elevated plasma lipoprotein (a) concentration is a known risk factor for atherosclerotic cardiovascular disease. In this paper, we discuss three hypotheses about the mechanisms by which lipoprotein (a) may be associated with pre-eclampsia: 1. Lp(a), as an acute-phase reactant, transporting cholesterol to sites of endothelial damage for reparation, temporarily increases during pregnancy and increases more during a pregnancy complicated by mild to moderate pre-eclampsia as compared to an uncomplicated pregnancy, in response to a greater extend of endothelial injury in pre-eclampsia. After delivery, pre-eclampsia subsides and Lp(a) concentrations return to baseline levels. 2. In cases of severe pre-eclampsia, there is even more extensive endothelial damage and consequently a higher consumption of Lp(a) in reparation of this vascular damage. These women will have lower concentrations of Lp(a). 3. High baseline concentrations of Lp(a), which are genetically determined, may induce or contribute to the development of pre-eclampsia by promoting endothelial dysfunction. In this line of reasoning one would expect to find higher concentrations of Lp(a) in women at risk for developing pre-eclampsia in a future pregnancy or with a history of pre-eclampsia. As discussed above, these women are also at increased risk for future cardiovascular disease as compared to women with a history of normal pregnancy. The pathophysiologic changes associated with cardiovascular disease may also be responsible for the increased incidence of pre-eclampsia in these women.