The relationship between pregnancy hypertension and later life hypertension is explained by long-term impacts of environmental oxidants on the vascular endothelium. These impacts may precede the onset of the disease as a primary defect and may participate in the pathogenesis of hypertension itself. Continuous exposure to strong exogenous oxidants such as NOx (NO and NO2) reversibly oxidizes oxyhemoglobin (Fe2+) to methemoglobin (Fe3+), and irreversible methemoglobinemia can arise because of disruption of the oxidant/antioxidant balance supported by SO2 metabolites, as inhibitors of antioxidants, and by synergistic degradation of antioxidant thiols. Methemoglobin by
itself and from heme, redox-active ferric iron as product of methemoglobin catabolism, have prooxidant properties and cause important structural and functional changes in the vascular endothelium such as growth arrest, senescence, morphological alterations and cell apoptosis.
Last date updated on July, 2014