Cysteinylation of maternal plasma albumin and its association with intrauterine growth restriction

Objectives We investigated cysteinylation of maternal plasma albumin in an observational study of intrauterine growth restriction (IUGR). High‐risk pregnancies and uteroplacental insufficiency (UPI) have been associated with elevated levels of homocysteine, and, in oxidizing environments, homocysteine is converted to cysteine, resulting in cysteinylation of proteins. Methods The study population included pregnancies with IUGR (n = 12) and uncomplicated pregnancies as controls (n = 8). In all cases, cysteinylation of maternal plasma albumin was measured in a blinded fashion using liquid chromatography coupled with electrospray ionization mass spectrometry. Results Markedly elevated maternal plasma levels of cysteinylated albumin were detected in pregnancies with IUGR (44.7 ± 14.8% of total albumin) compared to those in normal pregnancies (20.9 ± 6.1%). As a result, native albumin decreased from 52.5 ± 6.5% of total albumin in normal pregnancies to 30.1 ± 13.3% in IUGR pregnancies. Conclusions We hypothesize that sustained oxidative stress present in UPI is reflected by high levels of maternal cysteinylated albumin and may be a factor in the etiology of IUGR. Results of this preliminary study suggest that measurement of maternal plasma cysteinylated albumin may be useful for monitoring pregnancies associated with UPI and for detection of IUGR. Copyright © 2005 John Wiley & Sons, Ltd.