2-Methoxyoestradiol levels and placental catechol-O-methyltransferase expression in patients with late-onset preeclampsia

Purpose: Deficiencies in placental catechol-O-methyltransferase (COMT) and circulating 2-methoxyoestradiol (2-ME) have been shown to be related to early onset preeclampsia. The aim of this study was to investigate levels of 2-ME in the serum and urine of patients with late-onset preeclampsia and to compare those levels to those of normal pregnant women. In addition, we examined placental COMT expression in both groups. Methods: Fifteen patients with preeclampsia and 15 normal pregnant women were enrolled. 2-ME levels were evaluated by ELISA and placental COMT expression was examined by Western blot analysis. Results: 2-ME levels in serum [median 181.1 pg/mL, interquartile range (IQR) 119.6-244.3 vs. 61.2 pg/mL, IQR 12.0-133.7, respectively, p = 0.004] and urine (median 143.3 pg/mL, IQR 35.0-328.2 vs. 0.5 pg/mL, IQR 0.4-4.6, respectively, p < 0.001) were significantly increased in patients with late-onset preeclampsia compared to those in normal pregnant women at term. There was no significant difference in placental COMT expression between the two groups. Conclusion: Increased levels of 2-ME in patients with late-onset preeclampsia might be a product of a compensatory mechanism in patients with late-onset preeclampsia.