Prolactin fragmentation by trophoblastic matrix metalloproteinases as a possible contributor to peripartum cardiomyopathy and pre-eclampsia.

Although peripartum cardiomyopathy (PPCM) is a rare disease, it has very serious consequences for both mother and child. No single cause has been held responsible for the pathogenesis. Recent studies have indicated that increased proteolytic cathepsin D activity in cardiomyocytes results in16kDa prolactin fragments with anti-angiogenic and apoptotic properties, which may contribute to the development of PPCM. In support of these findings, lowering full-length prolactin production by bromocriptine therapy has been reported to prevent impairment of cardiac function. PPCM is associated with an increased co-existence of pre-eclampsia, however, a causal relationship has been disputed. We hypothesize that the pathophysiology of PPCM and pre-eclampsia share the same molecular pathway: increased activity of trophoblastic matrix metalloproteinases at the feto-maternal interface may aggravate proteolysis of full-length prolactin, and subsequently the formed 16kDa prolactin fragments may contribute to deterioration of PPCM and pre-eclampsia. Therefore, we argue that it may be worthwhile to explore wether prolactin inhibition is not only beneficial for PPCM patients, but also for the much more prevalent pre-eclamptic women.