PP039. ETK/BMX and renin-angiotensin system (RAS) components are differentially expressed in renal tissue in both normal and preeclamptic pregnancy

Abstract

Renal ETK/BMX activity is reduced in preeclampsia. Systemic RAS has been studied in preeclampsia; the renal RAS has not. None of the proteins in either pathway have previously been located in renal tissue from human pregnancy. To determine renal expression and distribution of proteins involved in the ETK/BMX and RAS pathways in normal and preeclamptic pregnancy. Limited residual tissue was available from renal biopsies in eight preeclamptic and seven healthy pregnant women. Immunohistochemistry was performed for AT1R, AT2R, angiotensinogen (AGT), prorenin, unphosphorylated ETK/BMX (uBMX) and phosphorylated ETK/BMX (pBMX). Immunohistochemical scoring was performed semiquantatively by a nephropathologist blinded to the original diagnosis. Results All proteins were renally expressed, AT1R equally in glomeruli and tubules, AT2R and prorenin more strongly in the tubules. If at all, uBMX was weakly expressed in glomeruli, and no glomerular pBMX expression was detected. Both uBMX and pBMX were strongly expressed in distal tubules. The material was too limited to detect differences between groups. The presence of prorenin, and both angiotensin receptors in the proximal tubule may indicate activation of the intra-renal RAS. Angiotensin II promotes sodium retention at the proximal tubule independently of aldosterone. Activated ETK/BMX in injured tubular epithelial cells is associated with cell repair and regeneration, proliferation and motility.