Low placental angiotensin-converting enzyme expression is related to fetal small for gestational age but not to metabolic control in type 1 diabetic pregnancies

The maternal renin-angiotensin system is involved in blood pressure control and plays a crucial role in fetoplacental nutrition. Pre-gestational type 1 diabetes (PGDM) leads to serious pregnancy complications. We thus performed a longitudinal study to analyse the association of maternal angiotensin-converting enzyme (ACE) serum levels and placental mRNA expression with fetal newborns gestational weight in type 1 diabetes mellitus (T1DM) women. We recruited 65 singleton pregnant women with T1DM. Placental mRNA ACE gene expression was examined using quantitative real-time PCR. Serum ACE levels were measured in the first, second and third trimesters of pregnancy by ELISA commercial kits. Placental expression of ACE mRNA was significantly lower in small for gestational age (SGA) than appropriate for gestational age (AGA) and large for gestational age (LGA) mothers (0.55±0.06 vs 0.78±0.06 and 0.85±0.07 respectively, p=0.003). In the SGA group, the mRNA expression of ACE positively correlated with maternal body mass index (BMI) in the third trimester (r=0.49; p=0.04). In all study groups maternal ACE level was significantly higher in the third trimester (mean 139.91±SD 69.64) compared to the first and second trimesters of pregnancy (13.57±4.32 and 15.69±15.92 respectively). Our data suggest that lower placental ACE gene mRNA expression may have a vital role in the etiology of SGA babies.