Background: Abnormal activation and/or dysfunction of the maternal vascular endothelium have been implicated as a cause of the placental ischemia and oxidative damage associated with pregnancy-induced hypertension (PIH).
Methods: To clarify the relationship between systemic oxidative stress and placental damage induced by reactive oxygen species (ROS), we immunostained placentas from 27 PIH pregnancies and 41 normal pregnancies for 8-hydroxy-2-deoxyguanosine (8OHdG).
Results: Positive 8OHdG staining was significantly more frequent in the syncytiotrophoblasts from PIH pregnancies compared to normal pregnancies matched for maternal age/gestational age at delivery. Comparison of 8OHdG positive and negative PIH patients revealed that antenatal serum uric acid (UA) was significantly higher, gestational age at delivery was significantly lower and early onset PIH was more frequent in patients with 8OHdG positive staining in the placenta.
Conclusion: These results suggest that ROS directly injures the placental syncytiotrophoblast in PIH patients and that elevated UA in PIH patients, at least partly, indicates placental damage induced by ROS. Moreover, the role and significance of ROS injury in the placenta may differ between early onset and late-onset type PIH.