Plasma hydrogen sulfide, nitric oxide, and thiocyanate levels are lower during pregnancy compared to postpartum in a cohort of women from the Pacific northwest of the United States.

AIMS

Pregnancy alters multiple physiological processes including angiogenesis, vasodilation, inflammation, and cellular redox, which are partially modulated by the gasotransmitters hydrogen sulfide (HS) and nitric oxide (NO). In this study, we sought to determine how plasma levels of HS, NO, and the HS-related metabolites thiocyanate (SCN), and methanethiol (CHSH) change during pregnancy progression.

MATERIALS AND METHODS

Plasma was collected from 45 women at three points: 25-28 weeks gestation, 28-32 week gestation, and at ≥3 months postpartum. Plasma levels of HS, SCN, and CHSH were measured following derivatization using monobromobimane followed by LC-MS/MS. Plasma NO was measured indirectly using the Griess reagent.

KEY FINDINGS

NO and SCN were significantly lower in women at 25-28 weeks gestation and 28-32 weeks gestation than postpartum while plasma HS levels were significantly lower at 28-32 weeks gestation than postpartum. No significant differences were observed in CHSH.

SIGNIFICANCE

Previous reports demonstrated that the production of HS and NO are stimulated during pregnancy, but we observed lower levels during pregnancy compared to postpartum. Previous reports on NO have been mixed, but given the related effects of HS and NO, it is expected that their levels would be higher during pregnancy vs. postpartum. Future studies determining the mechanism for decreased HS and NO during pregnancy will elucidate the role of these gasotransmitters during normal and pathological progression of pregnancy.