Abstract P212: Kidney Injury Caused By Preeclamptic Pregnancy Improves Postpartum In A Transgenic Rat Model

Abstract

Preeclamptic pregnancies involve mild renal injuries. However, there has been evidence that women with a history of preeclampsia (PE) have an increased risk to develop kidney disease in association to high blood pressure later in life. This study aims to characterize renal injury during pregnancy and postpartum in an established transgenic rat model for PE. Female Sprague-Dawley rats transgenic for the human angiotensinogen gene develop a PE phenotype in pregnancy, including cardiac remodeling, when mated with male rats harboring the human renin gene. Postpartum, blood pressure restores but cardiac remodeling persists. We hypothesize that PE during pregnancy mediates kidney injuries but does not fully restore after ending of the high blood pressure (postpartum). The renal alterations were analyzed by histological staining, gene expression and urine analysis. PE rats have elevated mean arterial blood pressure during pregnancy (PE d19 148.4 ± 20.7 mmHg) compared to normotensive values in control animals (WT d19 105.3 ± 4.6 mmHg). During PE increased expression of kidney injury marker 1 ( Kim-1/18S : PE d21 4.14 ± 3.26; WT d21 0.08 ± 0.02), neutrophil gelatinase associated lipocalin 2 ( Ngal/18S : PE d21 1.64 ± 0.83; WT d21 0.59 ± 0.28) and connective-tissue growth factor ( Ctgf/18S: PE d21 1.51 ± 0.46; WT d21 0.92 ± 0.32) were detected. Kidneys of PE rats showed mild glomerular (PAS-positive glomerular area PE d21 86.2 ± 4.4%; WT d21 79.1 ± 3.2%) and tubular changes during PE pregnancy resulting in albuminuria (albumin/creatinine ratio PE d19 2193.8 ± 1878.2; WT d19 290.4 ± 252.0). However, 4 weeks after pregnancy (approx. 2 years in humans) most of the PE related renal damages were absent including albuminuria and elevated expression of biomarkers ( Kim-1/18S : PE d50 0.09 ± 0.05; WT d50 0.23 ± 0.13; Ctgf/18S : PE d50 0.78 ± 0.25; WT d50 0.8 ± 0.25; Ngal/18S : PE d50 0.37 ± 0.17; WT 50 0.47 ± 0.11). Only mild enlargement of glomerular tuft area (PE d50 7523.8 ± 418.7 μm 2 ; WT d50 7058.4 ± 198.8 μm 2 ) was detected. Overall, the glomerular and tubular injuries are present during pregnancy in this transgenic PE rat. Most restore postpartum, speculating long-term kidney failure observed in humans is associated to hypertension and additional cardiovascular events.