NEW ADVANCES ON PLACENTAL HYDROPS AND RELATED VILLOUS LYMPHATICS

Abstract

Fetoplacental hydrops is the final stage ofseveral pathological conditions in which theplacenta and umbilical cord become edematousand the fetus develops an anasarcatic statecharacterized by an excessive accumulationof extravascular fluids in at least two serouscavities of the body. It is a common histologicalfinding of stillbirth, characterized bythe appearance of markedly edematous villi,suggesting an increased interstitial fluidaccumulation. The recent improved knowledgeof lymphangiogenesis and the availability ofmonoclonal antibodies selectively labelinglymphatic endothelium lead to the hypothesisthat villous edema is essentially a lymphedemafrom defective lymphatic function followinginadequate villous blood circulation. Lymphedemais a morphologic phenotype found byour research group in a 24-case series ofstillbirths from different morbid conditionssuch as chromosomal aberrations, congenitalmalformations, inherited hemoglobinopathies,and prolonged perinatal severe anoxia. Unlikelong-lived organs, the placenta is devoid ofinnervation by the autonomic nervous system;therefore, the vascular tone regulation andthe peripheral perfusion are modulated bythe expression of the angiotensin convertingenzyme (ACE) in the vascular endothelia.This finding may suggest to the clinician to search for a more suitable therapy in case ofmother’s hypertension during pregnancy.