The incidence of the metabolic syndrome, a cluster of abnormalities focusing on insulin resistance and associated with high risk for cardiovascular disease and diabetes, is reaching epidemic proportions. Prevalent in both developed and developing countries, the metabolic syndrome has largely been attributed to altered dietary and lifestyle factors that favour the development of central obesity. However, population-based studies have suggested that predisposition to the metabolic syndrome may be acquired very early in development through inappropriate fetal or neonatal nutrition. Further evidence for developmental programming of the metabolic syndrome has now been suggested by animal studies in which the fetal environment has been manipulated through altered maternal dietary intake or modification of uterine artery blood flow. This review examines these studies and assesses whether the metabolic syndrome can be reliably induced by the interventions made. The validity of the different species, diets, feeding regimes and end-point measures used is also discussed.
Abstract-Epidemiological studies suggest an association between maternal nutrition and offspring cardiovascular disease.We previously demonstrated endothelial dysfunction and abnormal aortic fatty acid composition in adult female offspring of rats fed animal lard during pregnancy. We have now further investigated this model. Female Sprague-Dawley rats were fed a control breeding diet (5.3% fat) or a diet rich in lard (25.7% fat) 10 days before and throughout pregnancy and lactation. Male and female offspring were implanted with radiotelemeters for recording of blood pressure, heart rate, and activity at 80, 180, and 360 days of age. Reactivity to acetylcholine and to nitric oxide were assessed in isolated small mesenteric arteries from 80-and 180-day-old littermates. Systolic blood pressure (awake phase) was raised in female offspring (180
Epidemiological and animal studies suggest that diet-induced epigenetic modifications in early life can contribute to development of the metabolic syndrome in adulthood. We previously reported features of the metabolic syndrome in adult offspring of rats fed a diet rich in animal fat during pregnancy and suckling. We now report a study to compare the relative effects of high-fat feeding during 1) pregnancy and 2) the suckling period in the development of these disorders. As observed previously, 6-mo-old female offspring of fat-fed dams suckled by the same fat-fed dams (OHF) demonstrated raised blood pressure, despite being fed a balanced diet from weaning. Female offspring of fat-fed dams "cross fostered" to dams consuming a control diet during suckling (OHF/C) demonstrated raised blood pressure compared with controls (OC) [systolic blood pressure (SBP; mmHg) means +/- SE: OHF/C, 132.5 +/- 3.0, n = 6 vs. OC, 119.0 +/- 3.8, n = 7, P < 0.05]. Female offspring of controls cross fostered to dams consuming the fat diet (OC/HF) were also hypertensive [SBP (mmHg) 131.0 +/- 2.5 mmHg, n = 6 vs. OC, P < 0.05]. Endothelium-dependent relaxation (EDR) of male and female OHF and OHF/C mesenteric small arteries was similar and blunted compared with OC (P < 0.001). OC/HF arteries showed profoundly impaired EDR (OC/HF vs. OHF, P < 0.001). OHF/C and OC/HF demonstrated hyperinsulinemia and increased adiposity. Features of the metabolic syndrome in adult offspring of fat-fed rats can be acquired both antenatally and during suckling. However, exposure during pregnancy confers adaptive protection against endothelial dysfunction induced by maternal fat feeding during suckling.
We previously reported that prenatal and suckling exposure to a maternal diet rich in animal fat leads to cardiovascular dysfunction in young adult rat offspring with subsequent development of dyslipidemia and hyperglycemia. We have further investigated glucose homeostasis in adult female offspring by euglycemic-hyperinsulinemic clamp and by dynamic assessment of glucose-stimulated insulin secretion in isolated, perifused pancreatic islet cells. Additionally, given the link between reduced mitochondrial DNA (mtDNA) content and the development of type 2 diabetes mellitus, we have measured mtDNA in organs from young adult animals. Sprague-Dawley rats were fed a diet rich in animal fat or normal chow throughout pregnancy and weaning. Infusion of insulin (5 mU.kg(-1).min(-1)) resulted in a higher steady-state plasma insulin concentration in 1-year-old offspring of fat-fed dams (OHF, n = 4) vs. offspring of control dams (OC, n = 4, P < 0.01). Glucose-stimulated insulin secretion in isolated islets from 9-mo-old OHF was significantly reduced compared with OC (n = 4, P < 0.05). Transmission electron micrography showed altered insulin secretory granule morphology in OHF pancreatic beta-cells. Kidney mtDNA was reduced in 3-mo-old OHF [16S-to-18S gene ratio: OC (n = 10) 1.05 +/- 0.19 vs. OHF (n = 10) 0.66 +/- 0.06, P < 0.05]. At 6 mo, gene chip microarray of OHF aorta showed reduced expression of the mitochondrial genome. Prenatal and suckling exposure to a diet rich in animal fat leads to whole body insulin resistance and pancreatic beta-cell dysfunction in adulthood, which is preceded by reduced tissue mtDNA content and altered mitochondrial gene expression.
Background-Population-based studies suggest that fetal adaptive responses to maternal dietary imbalance confer survival benefit when the postnatal diet remains suboptimal but increase susceptibility to cardiovascular disease when postnatal nutrition is improved. We have investigated "predictive adaptive" responses in a rodent model in which adult offspring of fat-fed dams develop characteristics of the metabolic syndrome. Methods and Results-Sprague-Dawley rats were fed a fat-rich diet or normal chow throughout pregnancy and weaning.Vascular endothelial function and blood pressure were determined in 180-day-old offspring of fat-fed dams raised on standard chow (FC) or on the fat-rich diet (FF) and in offspring of chow-fed dams raised on chow (CON
Epidemiological evidence suggests that populations consuming large amounts of soy protein have a reduced incidence of coronary heart disease (1–5). The cardiovascular risks associated with conventional hormone replacement therapy in postmenopausal women (5–7) have precipitated a search for alternative estrogen receptor modulators. Here we report that long‐term feeding of rats with a soy protein‐rich (SP) diet during gestation and adult life results in decreased oxidative stress, improved endothelial function, and reduced blood pressure in vivo measured by radiotelemetry in aged male offspring. Improved vascular reactivity in animals fed an SP diet was paralleled by increased mitochondrial glutathione and mRNA levels for endothelial nitric oxide synthase (eNOS) and the antioxidant enzymes manganese superoxide dismutase and cytochrome c oxidase. Reduced eNOS and antioxidant gene expression, impaired endothelial function, and elevated blood pressure in animals fed a soy‐deficient diet was reversed after refeeding them an SP diet for 6 months. Our findings suggest that an SP diet increases eNOS and antioxidant gene expression in the vasculature and other tissues, resulting in reduced oxidative stress and increased NO bioavailability. The improvement in endothelial function, increased gene expression, and reduced blood pressure by soy isoflavones have implications for alternative therapy for postmenopausal women and patients at risk of coronary heart disease.
We hypothesised that maternal uterine artery vascular dysfunction could contribute to cardiovascular dysfunction in offspring of rats fed a diet rich in fat. Sprague‐Dawley rats were fed for 10 days prior to pregnancy and throughout gestation either: (a) a control breeding diet, or (b) the same diet supplemented with 20% w/w lard, vitamins, essential micronutrients and protein to control values. At 20 days gestation vascular function was assessed in uterine arteries and third‐order mesenteric arteries. Vascular reactivity in response to application of potassium, noradrenaline, the thromboxane analogue U46619, acetylcholine and nitric oxide was assessed. Maternal plasma concentrations of factors likely to contribute to endothelial dysfunction were measured. Maximum acetylcholine‐induced relaxation was impaired in the mesenteric arteries of the lard‐fed dams (max% relaxation: lard‐fed, 69.7 ± 6.48; control, 85.37 ± 2.69, P = 0.03). Uterine artery vascular function was similar in the two groups (max% acetylcholine‐induced relaxation: lard‐fed, 73.7 ± 4.01; control, 77.5 ± 4.72, P = 0.98). Concentrations of plasma lipids, 8‐epi‐PGF2α and leptin were normal, whereas insulin and corticosterone concentrations were raised in the lard‐fed group (insulin (ng ml−1): lard‐fed, 8.04 ± 0.47; control, 1.35 ± 0.37, P < 0.0001; corticosterone (ng ml−1): lard‐fed, 1164.0 ± 170.9; control, 541.9 ± 96.3, P = 0.005). Fetal and placental weights were reduced in lard‐fed dams (fetus (g): lard‐fed, 4.27 ± 0.38; control, 2.96 ± 0.40, P = 0.025; placenta (g): lard‐fed, 0.72 ± 0.06; control, 0.57 ± 0.04, P = 0.05). Cardiovascular dysfunction in offspring is not associated with reduced uterine artery endothelial function but is associated with activation of the hypothalamic‐pituitary‐adrenal axis, hyperinsulinaemia and fetoplacental growth retardation.
We recently reported vascular dysfunction in adult offspring of rats fed a fat-rich (animal lard) diet in pregnancy. This study reports further characterization of constrictor and dilator function in mesenteric and caudal femoral arteries from 180-day-old offspring of dams fed the high fat diet (OHF). Endothelium-dependent relaxation in response to acetylcholine (10 −9 -10 −5 M) was impaired in mesenteric small arteries from male and female OHF compared with offspring of dams fed normal chow (males (maximum percentage relaxation): OHF 67.92 ± 2.89, n = 8 versus control 92.08 ± 2.19, n = 8, P < 0.01). Substantial relaxation in response to acetycholine in control mesenteric arteries remained after inhibition of nitric oxide synthase, soluble guanylate cyclase and cyclo-oxygenase but was blocked by 25 mM potassium. This component of relaxation, attributed to EDHF, was significantly reduced in OHF mesenteric arteries compared with controls. However, EDHF played a minor role in acetylcholine-induced relaxation in both control and OHF femoral caudal arteries (male and female). In these arteries, in contrast to mesenteric vessels, acetylcholine-induced relaxation was significantly enhanced in OHF but only in males (ACh (maximum percentage relaxation): OHF 58.40 ± 4.39, n = 8 versus male controls 32.18 ± 6.36, P < 0.05). This was attributable to enhanced nitric oxide-mediated relaxation. In conclusion, reduced endothelium-dependent relaxation in OHF mesenteric arteries is due to impaired EDHF-mediated relaxation. This defect was not apparent in femoral arteries in which EDHF has a less prominent role.
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