Placenta derived factors involved in the pathogenesis of the liver in the syndrome of haemolysis, elevated liver enzymes and low platelets (HELLP): A review.

Abstract

With this review we try to unravel if placenta-derived factors are able to initiate liver sinusoidal endothelial cells (LSEC) decay in HELLP syndrome and eventually cause the development of sinusoidal obstruction syndrome (SOS). Haemolysis, Elevated Liver enzymes and Low Platelets (HELLP) syndrome is a severe complication of pregnancy. It is characterized by elevated liver enzymes, low platelet count and haemolytic anaemia. The risk of developing HELLP syndrome within a pregnancy is 0.1-0.8%. The mortality rate among women with HELLP syndrome is 0-24% and the perinatal death goes up to 37%. The aetiology of HELLP syndrome is not fully understood but the pathogenesis of the liver pathology in the HELLP syndrome resembles that of a SOS with endothelial damage of the LSECs which ultimately leads to liver failure. We hypothesize that placenta derived factors cause LSEC damage and thereby liver dysfunction. We searched in the PubMed database for relevant articles about placenta derived factors involved in endothelial activation especially in the liver. We yielded eventually 55 relevant articles. Based on this literature search we associate that in HELLP syndrome there is an increase of soluble fms-like tyrosine kinase (sFlt1), vascular endothelial growth factor (VEGFR), soluble endoglin (sEng), galectin-1 (Gal-1), endothelin-1 (ET-1), Angiopoietin 2 (Angs-2), Asymmetric dimethylarginine (ADMA), activin B, inhibin A, Fas ligand (FasL) and heat shock protein 70 (Hsp70). We assume that these eleven increased placenta derived factors are responsible for LSEC damage which eventually leads to liver failure. This concept shows a possible design of the complicated pathophysiology in HELLP syndrome. However further research is required.