Placental System A Transporter mRNA is Not Different in Preeclampsia, Normal Pregnancy, or Pregnancies with Small-for-Gestational-Age Infants

Abstract

Objective: System A amino acid transporter activity is reduced in placentas from small-for-gestational-age (SGA) compared to normal pregnancies. We compared the expression of the system A transporters between preeclamptic and control and between small-for-gestational-age and controls pregnancies. Methods: We used placental samples from 18 preeclamptic pregnancies matched with 17 normal pregnancies and from 16 SGA pregnancies matched with 15 different normal pregnancies. Using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) we quantified the mRNA for two system A subtype target genes ATA1 and ATA2 as well as beta-actin for normalization. Results: There was no significant difference of mRNA for ATA1 or ATA2 transporters between preeclamptic and their controls or SGA pregnancies and their controls. Conclusions: Despite previous studies reporting reduced activity for system A transporters in small-for-gestational-age pregnancies, we found no difference in steady-state concentrations of the mRNA, of the system A transporters among preeclamptic, SGA, and normal control pregnancies. These resultsdo not exclude differences in actual protein levels or activity of the amino acid transporters, which warrant further study.