The role of p38alpha mitogen-activated protein kinase gene in the HELLP syndrome.

Mitogen-activated protein kinase (MAPK) p38alpha was shown to be implicated in the organogenesis of the placenta, and such placental alteration is crucial for the development of hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome. We aimed to analyze for the first time human placental expression of MAPK p38alpha in pregnancies complicated by HELLP. The placental expression of MAPK p38alpha was investigated by semiquantitative polymerase chain reaction using cDNA extracted from placental tissue of 15 pregnancies with HELLP syndrome and 15 gestational age-matched controls. Seven patients with HELLP also had intrauterine fetal growth restriction (IUGR). In placenta from pregnancy complicated by HELLP, the expression of MAPK p38alpha is significantly decreased compared to the group with normal pregnancy (p < 0.001), while no difference was found between the HELLP and HELLP with IUGR subpopulations. Our study shows for the first time that MAPK p38alpha is expressed in the human placenta. Pregnancies with placental dysfunction and hypertensive complications are characterized by a significantly decreased expression of MAPK p38alpha. Our observations suggest that p38 MAPK signaling may be essential in placental angiogenesis and functioning.