Effects of a postnatal high-salt diet on cardiac function in offspring from hypoxic pregnancies

Prenatal hypoxia is a common pregnancy complication that can permanently alter the structure and function of the fetal heart and predispose individuals to cardiovascular disease. However, the interactive effects of prenatal hypoxia and postnatal lifestyle choices are poorly studied. This study investigated the combined effects of prenatal hypoxia and a postnatal high-salt diet on cardiac function in adulthood. Pregnant Wistar rats were exposed to either 21% oxygen (normoxic group, n = 8) or 10.5% oxygen (hypoxic group, n = 8) from days 15 to 20 of gestation. Male offspring were divided into two groups at five weeks of age; normal salt (0.3 % NaCl) and high salt (8% NaCl) chow. Blood pressure and echocardiography measurements were performed at 18 weeks to assess cardiovascular function. Rats from hypoxic pregnancies had signs of pulmonary hypertension and right ventricular thickening, whereas rats fed a postnatal high-salt diet had systemic hypertension, left ventricular wall thickening and impaired relaxation. When prenatal hypoxia was combined with a postnatal high-salt diet, the rats exhibited a combination of the two phenotypes, but there were no significant interactions. Results suggest a poor postnatal diet can put additional strain on the cardiovascular system of offspring from hypoxic pregnancies, which can have significant implications for disease management. This article is part of the discussion meeting issue ‘Pregnancy at high altitude: the challenge of hypoxia’.