Human placental mast cells: a role in pre-eclampsia?

The human placenta contains a significant amount of histamine, a potent vasoconstrictor of the placental vasculature, shown by the author to be stored within the tissues' mast cells. The proposed hypothesis suggests that placental mast cells may have an important role in normal and, or pathological processes during pregnancy. This suggestion will be applied to the confounding problem of pre-eclampsia, a complication of pregnancy characterised by hypertension, oedema and proteinuria, which is associated with increased morbidity and mortality of mother and baby. It is postulated that pre-eclampsia reflects an inflammatory-type reaction, in which mast cell-mediated events play a significant role. The mediators released upon mast cell activation, such as histamine and prostaglandins, may be involved in the vasospasm that characterises pre-eclampsia; while processes such as uptake and clearance of vasoactive mediators by mast cells may be important in normotensive pregnancies and upset in those women who develop pre-eclampsia.