Prenatal Increased Asymmetric Dimethylarginine Is Associated with Placental Heat-Shock Protein 70 and Lectin-like Oxidized Low-Density Lipoprotein Receptor-1 Expression

Abstract

Background: Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, induces endothelial dysfunction by reversibly blocking NO production from L-arginine. To elucidate the association of prenatal status of ADMA with placental heat-shock protein 70 (HSP70) and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in normal full-term pregnancies, we evaluated the expression of placental HSP70 and LOX-1. Methods: Tissue samples of placentas obtained from 60 normal-term pregnancies were categorized into 30 cases with a lower level of prenatal ADMA (0.28 ± 0.07 μM) and 30 cases with a higher level of prenatal ADMA (1.31 ± 0.44 μM). We evaluated the placental expression of HSP70 and LOX-1 with Western blot analysis and immunohistochemistry and determined the correlation between HSP70 and LOX-1. Results: We found that prenatal increased ADMA is associated with increased placental HSP70 and LOX-1 expression. Conclusions: We postulate that higher ADMA levels are associated with excessive levels of oxidative damage and stress markers (HSP, LOX-1) in placental tissues. © 2007 IMSS.