F2-isoprostanes and fatty acids profile in early pregnancy complicated by pre-existing diabetes

Abstract

Background: Diabetes and pregnancy are both associated with oxidative stress, characterized by an increase of F₂-isoprostanes from the non-enzymatic oxidation of arachidonic acid, a n - 6 polyunsaturated fatty acid (PUFA). We hypothesized that pregnant women with pre-existing diabetes will be characterized by elevated levels of specific F₂-isoPs isomers and altered PUFA composition in plasma early pregnancy when compared to normoglycemic controls.

Methods: Plasma samples from 23 women with uncomplicated pregnancies and 11 women with pre-existing diabetes in pregnancy were collected between 12 and 18 weeks of pregnancy (MIROS cohort). Six F₂-isoprostanes isomers were measured by high-performance liquid chromatography coupled to tandem mass spectrometry. Fatty acids concentrations in plasmatic phospholipids were measured by gas chromatography coupled to a flame ionization detector.

Results: F₂-isoprostanes, specifically the 8-iso-15(R)-PGF₂α levels, were 67% higher in diabetic than normoglycemic pregnancies (p = 0.026). The total n - 6 PUFA and arachidonic acid level did not differ between study groups. In contrast, total n - 3 level was 32% lower in diabetic pregnancies than in controls (p = 0.002); EPA(20:5) and DHA(22:6) being specifically reduced (p = 0.035 and p = 0.003 respectively). Delta-6-desaturase (D6D) activity index, calculated using fatty acid ratios, was 9% lower in pre-existing diabetes than in controls (p = 0.042).

Conclusions: Pre-existing diabetes in early pregnancy displays a distinctive F₂-isoprostanes profile when compared to other pathologies of pregnancy, such as preeclampsia, as previously assessed in the same cohort.

Keywords: Delta-6-desaturase; Hyperglycemia; Omega-3 fatty acids; Oxidative stress.