Background and aimsFetal undernutrition is a risk factor for heart disease in both genders, despite the protection of women against hypertension development. Using a rat model of maternal undernutrition (MUN) we aimed to assess possible sex differences in the development of cardiac alterations and the implication of hypertension and cardiac oxidative stress.MethodsMale and female offspring from rats fed ad libitum (control) or with 50% of the normal daily intake during the second half of gestation (MUN) were used. Heart weight/body weight ratio (HW/BW), hemodynamic parameters (anaesthetized rats) and plasma brain natriuretic peptide (BNP, ELISA) were assessed in 21-day, 6-month and 22-month old rats. Plasma testosterone (ELISA) and cardiac protein expression of enzymes related to reactive oxygen species synthesis (p22phox, xanthine-oxidase) and degradation (catalase, Cu/Zn-SOD, Mn-SOD, Ec-SOD) were evaluated in 21-day and 6-month old rats (Western Blot). Heart structure and function was studied at the age of 22 months (echocardiography).ResultsAt the age of 21 days MUN males exhibited significantly larger HW/BW and cardiac p22phox expression while females had reduced p22phox expression, compared to their respective sex-matched controls. At the age of 6-months, MUN males showed significantly larger blood pressure and cardiac xanthine-oxidase expression; MUN females were normotensive and had a lower cardiac expression of antioxidant enzymes, compared to their respective sex-matched controls. At the age of 22 months, both MUN males and females showed larger HW/BW and left ventricular mass and lower ejection fraction compared to sex-matched controls; only MUN males exhibited hypertension and a larger plasma BNP compared to aged male controls.Conclusions1) During perinatal life females exposed to fetal undernutrition are protected from cardiac alterations, but in ageing they exhibit ventricular hypertrophy and functional loss, like MUN males; 2) cardiac oxidative stress might be implicated in the observed heart alterations in both sexes and 3) the severity of cardiac damage might be greater in males due to hypertension.
In early normal gestation, low plasma antioxidant status, assessed through a global score, associates with later development of pregnancy complications. Larger population studies could help to determine the value of Antiox-S as predictive tool and the relevance of nutrition on maternal antioxidant status.
Fetal undernutrition programmes hypertension development, males being more susceptible. Deficient fetal elastogenesis and vascular growth is a possible mechanism. We investigated the role of aortic mechanical alterations in a rat model of hypertension programming, evaluating changes at birth, weaning and adulthood. Dams were fed ad libitum (Control) or 50% of control intake during the second half of gestation (maternal undernutrition, MUN). Offspring aged 3 days, 21 days and 6 months were studied. Blood pressure was evaluated in vivo. In the thoracic aorta we assessed gross structure, mechanical properties (intact and purified elastin), collagen and elastin content and internal elastic lamina (IEL) organization. Only adult MUN males developed hypertension (systolic blood pressure: MUN = 176.6 ± 5.6 mmHg; Control = 136.1 ± 4.9 mmHg). At birth MUN rats were lighter, with smaller aortic cross-sectional area (MUN = (1.51 ± 0.08) × 10 μm , Control = (2.8 ± 0.04) × 10 μm ); during lactation MUN males and females exhibited catch-up growth and aortic hypertrophy (MUN = (14.5 ± 0.5) × 10 μm , Control = (10.4 ± 0.9) × 10 μm ), maintained until adulthood. MUN aortas were more compliant until weaning (functional stiffness: MUN = 1.0 ± 0.04; Control = 1.3 ± 0.03), containing less collagen with larger IEL fenestrae, returning to normal in adulthood. Purified elastin from young MUN offspring was more compliant in both sexes; only MUN adult females maintained larger elastin compliance (slope: MUN = 24.1 ± 1.9; Control = 33.3 ± 2.8). Fetal undernutrition induces deficient aortic development followed by hypertrophic remodelling and larger aortic compliance in the perinatal period, with similar alterations in collagen and elastin in both sexes. The observed alterations argue against an initial mechanical cause for sex differences in hypertension development. However, the maintenance of high elastin compliance in adult females might protect them against blood pressure rise.
Intrauterine and perinatal life are critical periods for programming of cardiometabolic diseases. However, their relative role remains controversial. We aimed to assess, at weaning, sexdependent alterations induced by fetal or postnatal nutritional interventions on key organs for metabolic and cardiovascular control. Fetal undernutrition was induced by dam food restriction (50 % from mid-gestation to delivery) returning to ad libitum throughout lactation (Maternal Undernutrition, MUN, 12 pups/litter). Postnatal overfeeding (POF) was induced by litter size reduction from normally fed dams (4 pups/litter). Compared to control, female and male MUN offspring exhibited: 1) low birth weight and accelerated growth, reaching similar weight and tibial length by weaning, 2) increased glycemia, liver and white fat weights; 3) increased ventricular weight and tendency to reduced kidney weight (males only). Female and male POF offspring showed: 1) accelerated growth; 2) increased glycemia, liver and white fat weights; 3) unchanged heart and kidney weights. In conclusion, postnatal accelerated growth, with or without fetal undernutrition, induces early alterations relevant for metabolic disease programming, while fetal undernutrition is required for heart abnormalities. The progression of cardiac alterations and their role on hypertension development needs to be evaluated.The similarities between sexes in pre-pubertal rats suggest a role of sex-hormones in female protection against programming.
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