Exercise during pregnancy mitigates the adverse effects of maternal obesity on adult male offspring vascular function and alters one-carbon metabolism

Abstract

Maternal obesity during pregnancy can adversely affect adult offspring vascular endothelial function. This study examined whether maternal exercise during pregnancy and lactation mitigates the adverse effects of maternal obesity on offspring vascular endothelial function. Female (C57BL/6N) mice were fed from weaning a control diet (10% kcal fat) or western diet (45% kcal fat) to induce excess adiposity (maternal obesity). After 13 weeks, the female mice were bred and maintained on the diets, with and without access to a running wheel (exercise), throughout breeding, pregnancy, and lactation. Offspring were weaned onto the control or western diet and fed for 13 weeks; male offspring were studied. Maternal exercise prevented the adverse effects of maternal obesity on offspring vascular endothelial function. However, this was dependent on offspring diet and the positive effect of maternal exercise was only observed in offspring fed the western diet. This was accompanied by alterations in aorta and liver one-carbon metabolism, suggesting a role for these pathways in the improved endothelial function observed in the offspring. Obesity and exercise had no effect on endothelial function in the dams but did affect aorta and liver one-carbon metabolism, suggesting the phenotype observed in the offspring may be due to obesity and exercise-induced changes in one-carbon metabolism in the dams. Our findings demonstrate that maternal exercise prevented vascular dysfunction in male offspring from obese dams and is associated with alterations in one-carbon metabolism.

Keywords: endothelial function; exercise; maternal obesity; offspring; one-carbon metabolism.

FIGURE 1

Study design. Female C57BL/6N mice (dams) were fed either a control (control dams) or western diet(obese dams) from weaning (age 3 weeks). At 12‐weeks post weaning, dams were put into cages with (exercise) or without (sedentary) a running wheel. The dams were bred with male mice fed the control diet 1 week later. Dams had access to the running wheel throughout breeding, pregnancy and lactation. Offspring were weaned at age 3 weeks onto the control diet or western diet and fed for 14 weeks

FIGURE 2

Exercise during pregnancy and lactation in the dams. (a) Average running distance per day during the first week of exercise and (b) average distance ran per day from one week before breeding until the end of lactation. (c), Citrate synthase activity in quadricep muscle. Values for each individual mouse presented; bar graphs represent mean ± SD (n = 8–14/group)

FIGURE 3

Exercise during pregnancy and lactation lowered fat mass but had no effect on glucose tolerance or thoracic aorta endothelial‐dependent and independent vasodilatation in the dams. (a) Body weight at 15 weeks of age, just prior to exercise; and (b) throughout breeding, pregnancy and lactation. (c) Total body fat percentage at the end of lactation. (d) Fasting blood glucose; (e) intraperitoneal glucose tolerance test; and (f) area under the glucose excursion curve at the end of lactation. (g) Acetylcholine (Ach)‐induced and (h) sodium nitroprusside (SNP)‐induced vasodilatation of aortic rings preconstricted with phenylephrine (10^–5 M) at age 23 weeks. Values for each individual mouse presented; bar graphs represent mean ± SD (n = 8–14/group). For vascular function graphs, data symbols represent mean ± SD. Exe, exercise; Sed, sedentary

FIGURE 4

Exercise in dams with diet‐induced obesity improved thoracic aorta endothelial‐dependent vasodilatation in adult male offspring fed the western diet. (a) Offspring body weight at weaning; and (b) in adulthood (age 17 weeks). Offspring were fed the western diet. Endothelial‐dependent vasodilatation in response to increasing acetylcholine (Ach) concentrations in (c) offspring from dams with diet‐induced obesity and (d) offspring from control dams . Endothelialindependent vasodilatation in response to increasing sodium nitroprusside (SNP) concentrations in (e) offspring from dams with diet‐induced obesity and (f) offspring from control dams. (g) Vasoconstriction assessed in response to phenylephrine. Bar graphs represent mean ± SD, values for each individual mouse presented; (n = 7–11/group). For wire myograph curves, symbols represent mean ± SD (n = 5–6/group) at each drug concentration

FIGURE 5

Exercise in dams with diet‐induced obesity had no effect on thoracic aorta endothelial‐dependent vasodilatation in adult male offspring fed the control diet. (a) Control diet‐fed offspring body weight at weaning and (b) at age 14 weeks. At age 14–15 weeks, aortic rings were harvested from offspring and vasodilatation were assessed in response to (c,d) acetylcholine (Ach) and (e,f) sodium nitroprusside (SNP) for endothelial‐dependent and endothelial‐independent vasodilatation, respectively. (g) Vasoconstriction assessed in response to phenylephrine . For bar graphs, values for each individual mouse presented; bar graphs represent mean ± SD (n = 7–11/group). Symbols represent mean ± SD (n = 5–6/group) at each drug concentration. Data were analyzed by repeated measures ANOVA and symbols represent mean ± SD

FIGURE 6

Maternal diet‐induced obesity reduced basal nitric oxide production in thoracic aorta from adult male offspring fed the western diet. Phenylephrine (PE)‐induced contraction in aortic rings, with or without the nitric oxide synthase inhibitor NG‐nitro‐Larginine methyl ester (L‐NAME), from (a,b) offspring fed the western diet or (d,e) control diet. Difference in the area under the curve (AUC) between contraction curves with and without L‐NAME in offspring fed the (c) western diet or (f) control diet. For contraction curves, symbols represent mean ± SD for each group at each PE concentration. For bar graphs, values for each mouse presented; bar graphs represent mean ± SD (n = 5–6/group)

FIGURE 7

Maternal exercise increased serum nitrate and nitrite concentrations in male offspring fed (a) the western diet but not in those fed (b) the control diet. Values for each mouse presented; bar graphs represent mean ± SD (n = 4–6/group)

FIGURE 8

Aortic endothelial cell gene expression profile in offspring fed the western diet. (a) Representative scattergram of FACS analyses to isolate aortic endothelial cells. Cells were first gated to exclude CD45+ and 7AAD+ cells then CD31+, CD105+, and CD31+/CD105+ were sorted as endothelial cell population. Isolated endothelial cell functionality was confirmed by ac‐dil‐LDL uptake assay in sorted (b) endothelial cells and (c) CD45‐/CD31‐/CD105‐. (d) Gene expression analysis of isolated aortic endothelial cells using a NanoString panel and normalized to housekeeping genes

FIGURE 9

Maternal exercise alters one‐carbon metabolism in adult offspring fed the western diet. (a) Schematic simplified representation of one‐carbon metabolism. (b) Aorta Dhfr mRNA. (c) Serum total folate concentrations. Liver (d) Mat1a, (e) Mthfr, (f) Mtrr, and (g) Cbs mRNA. Serum total (h) homocysteine and total (i) cysteine concentrations. Values for each individual mouse presented; bar graphs represent mean ± SD (n = 4‐6/group). Abbreviations: BH₂, dihydrobiopterin; BH₄, tetrahydrobiopterin; Cbs, cystathionine β‐synthase; Cth, cystathionine γ‐lyase; Dhfr, dihydrofolate reductase; eNOS, endothelial nitric oxide synthase; Mat1a, methionine adenosyltransferase; 5‐MTHF, 5‐methyltetrahydrofolate; 5,10‐MTHF, 5,10‐methylenetetrahydrofolate; Mthfr, methylenetetrahydrofolate reductase; Mtr, methionine synthase; Mtrr, methionine synthase reductase; NO, nitric oxide; S‐AdoHcy, S‐adenosylhomocysteine; S‐AdoMet, Sadenosylmethionine; THF, tetrahydrofolate

FIGURE 10

Exercise during pregnancy altered mRNA expression of one‐carbon metabolism in the dams. (a) Aortic Dhfr (dihydrofolate reductase) mRNA expression in dams. Serum total (b) homocysteine, (c) cysteine, and (c) folate concentrations in dams. Hepatic mRNA expression of (e) Mtrr (methionine synthase reductase) and (f) Mat1a (methionine adenosyltransferase) in dams aged 23–26 weeks. Values for each individual mouse presented; bar graphs represent mean ± SD (n = 5–6/group)