Maternal salt and fat intake causes hypertension and sustained endothelial dysfunction in fetal, weanling and adult male resistance vessels

Abstract

Maternal salt and fat intake can independently programme adult cardiovascular status, increasing risk of cardiovascular disease in offspring. Despite its relevance to modern western-style dietary habits, the interaction between increased maternal salt and fat intake has not been examined. Female virgin Sprague-Dawley rats were fed, a standard control diet (CD) (10% kcal fat, 1% NaCl), High-fat diet (HF) (45% kcal fat, 1% NaCl), High-salt diet (SD) (10% kcal fat, 4% NaCl), High-fat high-salt diet (HFSD) (45% kcal fat, 4% NaCl) prior to pregnancy, during pregnancy and throughout lactation. Fetal, weanling and adult vessels were mounted on a pressure myograph at fetal day 18, weaning day 21 and day 135 of adulthood. Increased blood pressure in SD, HFD and HFSD male offspring at day 80 and 135 of age was consistent with perturbed vascular function in fetal, weanling and adult vessels. Maternal salt intake reduced EDHF and calcium-mediated vasodilation, maternal fat reduced NO pathways and maternal fat and salt intake, a combination of the two pathways. Adult offspring cardiovascular disease risk may, in part, relate to vascular adaptations caused by maternal salt and/or fat intake during pregnancy, leading to persistent vascular dysfunction and sustained higher resting blood pressure throughout life.

Figure 1

(a) Systolic blood pressure (SBP) at postnatal day 80 in male offspring as quantified via tail-cuff plethysmography. *p < 0.001 for SD, HF & HFSD versus CON. All data are means ± SEM, n = 10/group. Different dietary groups are defined as; Control group = CD, Salt group = SD, High fat group = HF and Salt and Fat combined group = HFSD, n = 10/group.(b). Systolic blood pressure (SBP) at postnatal day 135 in male offspring as quantified via tail-cuff plethysmography. *p < 0.001 for SD, HF & HFSD versus CON. All data are means ± SEM, n = 10/group. Different dietary groups are defined as; Control group = CD, Salt group = SD, High fat group = HF and Salt and Fat combined group = HFSD, n = 10/group.

Figure 2

(a) Fetal offspring mesenteric vessel responsiveness following phenylephrine (PE) treatment, measured as % change from initial resting diameter and normalised as % maximum constriction in CD , SD , HF and HFSD fetuses. All data are means ± SEM. Different dietary groups are defined as; Control group = CD, Salt group = SD, High fat group = HF and Salt and Fat combined group = HFSD, n = 10/group. (b) Fetal femoral vessel responsiveness following cumulative addition of vasodilator ACh measured as % change from initial resting diameter after pre-constriction with PE (10 μM) in the presence of TRAM-34 (1 μM), Apamin (3 μM) and INDO (10 μM). All data are means ± SEM. * p < 0.001 for HF versus CD. ** p < 0.001 for HFSD versus CD. Different dietary groups are defined as; Control group = CD, Salt group = SD, High fat group = HF and Salt and Fat combined group = HFSD, n = 8/group. (c) Fetal femoral vessel responsiveness following cumulative additions of vasodilator ACh measured as % change from initial resting diameter after pre-constriction with PE (10 μM) in the presence of L-NAME (100 μM), INDO (10 μM) and ODQ (5 μM). All data are means ± SEM. * p < 0.001 for SD versus all other groups. Different dietary groups are defined as; Control group = CD, Salt group = SD, High fat group = HF and Salt and Fat combined group = HFSD, n = 8/group.

Figure 3

(a) Weanling offspring mesenteric vessel responsiveness following phenylephrine (PE) treatment, measured as % change from initial resting diameter and normalised as % maximum constriction in CD, SD, HF and HFSD weanling male offspring. All data are means ± SEM. Different dietary groups are defined as; Control group = CD, Salt group = SD, High fat group = HF and Salt and Fat combined group = HFSD, n = 10/group. (b) Weanling mesenteric vessel responsiveness following cumulative addition of vasodilator ACh measured as % change from initial resting diameter after pre-constriction with PE (10 μM) in the presence of TRAM-34 (1 μM), Apamin (3 μM) and INDO (10 μM). All data are means ± SEM. * p < 0.001 for HF versus CD. ** p = 0.04 for HFSD versus CD. Different dietary groups are defined as; Control group = CD, Salt group = SD, High fat group = HF and Salt and Fat combined group = HFSD, n = 8/group. (c) Weanling mesenteric vessel responsiveness following cumulative additions of vasodilator ACh measured as % change from initial resting diameter after pre- constriction with PE (10 μM) in the presence of L-NAME (100 μM), INDO (10 μM) and ODQ (5 μM). All data are means ± SEM. * p < 0.001 for SD versus all other groups. Different dietary groups are defined as; Control group = CD, Salt group = SD, High fat group = HF and Salt and Fat combined group = HFSD, n = 8/group.

Figure 4

(a) Adult offspring mesenteric vessel responsiveness following phenylephrine (PE) treatment, measured as % change from initial resting diameter and normalised as % maximum constriction in CD, SD, HF and HFSD adult male offspring. All data are means ± SEM. Different dietary groups are defined as; Control group = CD, Salt group = SD, High fat group = HF and Salt and Fat combined group = HFSD, n = 10/group. (b) Adult offspring mesenteric vessel responsiveness following cumulative addition of vasodilator ACh measured as % change from initial resting diameter after pre-constriction with PE (10 μM) in the presence of TRAM-34 (1 μM), Apamin (3 μM) and INDO (10 μM). All data are means ± SEM. * p < 0.001 for HF versus CD. ** p = 0.001 for HFSD versus CD. Different dietary groups are defined as; Control group = CD, Salt group = SD, High fat group = HF and Salt and Fat combined group = HFSD, n = 10/group. (c) Adult mesenteric vessel responsiveness following cumulative additions of vasodilator ACh measured as % change from initial resting diameter after pre-constriction with PE (10 μM) in the presence of L-NAME (100 μM), INDO (10 μM) and ODQ (5 μM). All data are means ± SEM. * p < 0.001 for SD versus all other groups. Different dietary groups are defined as; Control group = CD, Salt group = SD, High fat group = HF and Salt and Fat combined group = HFSD, n = 10/group.

Figure 5

Effects of maternal diet on mRNA expression in male weanling offspring vessels. (a) Bar graph indicates fold change in eNOS mRNA expression present in CD, SD, HF and HFSD weanling offspring vessels. (b) Bar graph indicates fold change in COX-1 mRNA expression present in CD, SD, HF, HFSD weanling offspring vessels. (c) Bar graph indicates fold change in COX-2 mRNA expression present in CD, SD, HF, HFSD weanling offspring vessels. *denotes p < 0.001 vs. Control offspring. All data are means ± SEM, n = 7 per group.

Figure 6

Effects of maternal diet on mRNA expression in male adult offspring vessels. (a) Bar graph indicates fold change in eNOS mRNA expression present in CD, SD, HF and HFSD adult offspring vessels. (b) Bar graph indicates fold change in COX-1 mRNA expression present in CD, SD, HF, HFSD adult offspring vessels. (c) Bar graph indicates fold change in COX-2 mRNA expression present in CD, SD, HF, HFSD adult offspring vessels. *denotes p < 0.001 vs. Control offspring. All data are means ± SEM, n = 7 per group.