It has been hypothesized that in preeclampsia, the antioxidant-deficient state may facilitate increased attacks of free radicals, which may result in endothelial cell damage. The purpose of this study was to investigate the association of three lipid-soluble antioxidants, coenzyme Q₁₀, α-tocopherol and γ-tocopherol, with preeclampsia and normal pregnancy. Serum levels of all three antioxidants in 42 women with normal pregnancies, 25 with mild preeclampsia and 28 with severe preeclampsia were measured by high-pressure liquid chromatography. A significant decrease was observed in serum levels of coenzyme Q₁₀ and α-tocopherol (p < 0.001 for each by the Kruskal-Wallis rank test) in women with preeclampsia compared to levels in normal pregnancy. γ-Tocopherol levels were comparable among the different groups. Logistic regression analysis revealed significant association between grades of preeclampsia and both serum coenzyme Q₁₀ and α-tocopherol levels (p = 0.000 and 0.030, respectively). Coenzyme Q₁₀ and α-tocopherol are potent antioxidants, and the decreased levels of these two antioxidants in preeclampsia may alter the normal redox balance, thereby reducing the ability of antioxidant defenses to protect against free radical damage. This could be a factor in the endothelial cell damage observed in preeclampsia.

Cervical intraepithelial neoplasia (CIN) may, at times, unpredictably progress to invasive carcinoma of the cervix. Epidemiological nutritional studies suggest that higher dietary consumption and circulating levels of certain micronutrients may be protective against cervical cancer. However, a preventive role of dietary antioxidants in CIN is not well established. The purpose of this cross-sectional study was to investigate the comparative plasma concentrations of three potent antioxidants, coenzyme Q(10,) alpha-tocopherol and gamma-tocopherol, in women with normal Pap smears and patients with a biopsy-confirmed histopathological lesion diagnosed as CIN or cervical cancer. Plasma concentrations of coenzyme Q(10,) alpha-tocopherol and gamma-tocopherol were measured by high-pressure liquid chromatography in both normal women without any history of abnormal Pap smears (n=48), and patients with histopathologically confirmed diagnoses of: (a) CIN I, n=98; (b) CIN II, n=49; (c) CIN III, n=10; and (d) cervical cancer, n=25. The mean plasma levels of coenzyme Q(10), alpha-tocopherol and gamma-tocopherol were significantly lower (P<0.001,<0.001, and<0.001, respectively by Kruskal-Wallis test) in patients with various grades of CIN and cervical cancer compared with controls. After controlling for age and smoking, an inverse association between histological grades of epithelial lesions and both plasma coenzyme Q(10) and alpha-tocopherol concentrations was observed. The low plasma concentrations of coenzyme Q(10) may be due to deficient dietary intake or a decrease in endogenous coenzyme Q(10) biosynthesis that may reflect increased utilization as a result of free radical reactive oxygen species induced oxidative stress. Further molecular studies on the mechanistic role of antioxidants in women with precancer cervical lesions are needed.

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