Increased DNA damage in patients with complete hydatidiform mole

The pathologic mechanisms underlying the gestational trophoblastic diseases are largely unexplored, but are thought to involve oxidative damage to the maternal vasculature and also to the placenta. In this study we have assessed the plasma levels of total antioxidant response (TAR) and the levels of endogenous DNA damage - determined by the comet assay - in peripheral blood lymphocytes from 13 women with complete hydatidiform mole (CHM) and compared these with those of 12 healthy pregnant controls and 10 healthy non-pregnant controls. Significantly lower mean levels of plasma TAR were found in patients with CHM compared with healthy pregnant controls (1.08 ± 0.29 versus 1.17±0.14 mmol Trolox Eq/L, p < 0.05) and with healthy non-pregnant controls (1.08 ± 0.29 versus 1.38 ± 0.12 mmol Trolox Eq/L, p < 0.05). Significantly higher mean levels of endogenous DNA damage were observed in patients with CHM than in healthy pregnant controls (234.5 ± 50.74 versus 125.7 ± 45.4 AU, p < 0.05) or in healthy non-pregnant controls (234.5 ± 50.74 versus 104.0 ± 49.6 AU, p < 0.05). We observed an inverse correlation between the plasma TAR and the levels of endogenous DNA damage (r= -0.64, p < 0.01), in that the levels of oxidative damage to the DNA were found to parallel the decrease in the plasma TAR in the CHM group. These results reveal a relationship between the extracellular and intracellular (as reflected by damage to the DNA) levels of oxidation. Our observations suggest that there is a link between the increased levels of oxidative stress and the increase in endogenous DNA damage seen in patients with CHM, as compared with those seen in normal pregnancy. However, the nature of this link, and whether it is direct or indirect, remains to be explored.