Both prenatal under- and overnutrition predisposed for abdominal adiposity, apparently by reducing the expandability of subcutaneous adipose tissue and induced differential physiological adaptations to fasting. This study does not suggest that exposure to gestational overnutrition will provide a protective effect against development of hyperglycaemia later in life.
We have developed a sheep model to facilitate studies of the fetal programming effects of mismatched perinatal and postnatal nutrition. During the last trimester of gestation, twenty-one twin-bearing ewes were fed a normal diet fulfilling norms for energy and protein (NORM) or 50 % of a normal diet (LOW). From day 3 postpartum to 6 months (around puberty) of age, one twin lamb was fed a conventional (CONV) diet and the other a high-carbohydrate -high-fat (HCHF) diet, resulting in four groups of offspring: NORM-CONV; NORM-HCHF; LOW-CONV; LOW-HCHF. At 6 months of age, half of the lambs (all males and three females) were slaughtered for further examination and the other half (females only) were transferred to a moderate sheep diet until slaughtered at 24 months of age (adulthood). Maternal undernutrition during late gestation reduced the birth weight of LOW offspring (P, 0·05), and its long-term effects were increased adrenal size in male lambs and adult females (P, 0·05), increased neonatal appetite for fat-(P¼0·004) rather than carbohydrate-rich feeds (P,0·001) and reduced deposition of subcutaneous fat in both sexes (P,0·05). Furthermore, LOW-HCHF female lambs had markedly higher visceral:subcutaneous fat ratios compared with the other groups (P, 0·001). Postnatal overfeeding (HCHF) resulted in obesity (. 30 % fat in soft tissue) and widespread ectopic lipid deposition. In conclusion, our sheep model revealed strong pre-and postnatal impacts on growth, food preferences and fat deposition patterns. The present findings support a role for subcutaneous adipose tissue in the development of visceral adiposity, which in humans is known to precede the development of the metabolic syndrome in human adults.
Prenatal malnutrition differentially programmed glucose-lactate metabolic pathways and cholesterol homeostasis. Prenatal overnutrition predisposed for hyperglycaemia and hyperlactataemia, whereas undernutrition predisposed for hypercholesterolaemia upon exposure to an obesogenic diet. Prenatal overnutrition (not undernutrition) interfered with pancreatic insulin secretion by non-glucose-dependent mechanisms.
We aimed to investigate whether over- versus undernutrition in late foetal life combined with obesity development in early postnatal life have differential implications for fat distribution and metabolic adaptability in adulthood. Twin-pregnant ewes were fed NORM (100% of daily energy and protein requirements), LOW (50% of NORM) or HIGH (150%/110% of energy/protein requirements) diets during the last trimester. Postnatally, twin-lambs received obesogenic (HCHF) or moderate (CONV) diets until 6 months of age, and a moderate (obesity correcting) diet thereafter. At 2½ years of age (adulthood), plasma metabolite profiles during fasting, glucose, insulin and propionate (in fed and fasted states) tolerance tests were examined. Organ weights were determined at autopsy. Early obesity development was associated with lack of expansion of perirenal, but not other adipose tissues from adolescence to adulthood, resulting in 10% unit increased proportion of mesenteric of intra-abdominal fat. Prenatal undernutrition had a similar but much less pronounced effect. Across tolerance tests, LOW-HCHF sheep had highest plasma levels of cholesterol, urea-nitrogen, creatinine, and lactate. Sex specific differences were observed, particularly with respect to fat deposition, but direction of responses to early nutrition impacts were similar. However, prenatal undernutrition induced greater metabolic alterations in adult females than males. Foetal undernutrition, but not overnutrition, predisposed for adult hypercholesterolaemia, hyperureaemia, hypercreatinaemia and hyperlactataemia, which became manifested only in combination with early obesity development. Perirenal expandability may play a special role in this context. Differential nutrition recommendations may be advisable for individuals with low versus high birth weights.
Mounting evidence led us to hypothesize that i) function of the thyroid hormone (TH) axis can be programed by late gestation undernutrition (LG-UN) and ii) early-postnatal-life overnutrition (EL-ON) exacerbates the fetal impacts on TH axis function. In a 2!2 factorial experiment, 21 twin-bearing sheep were fed one of two diets during late gestation: NORM (fulfilling energy and protein requirements) or LOW (50% of NORM). From day 3 to 6 months after birth (around puberty), the twin lambs were assigned to each their diet: conventional (CONV) or high-carbohydrate, high-fat, where after half the lambs were killed. Remaining sheep (exclusively females) were fed the same moderate diet until 2 years of age (young adults). At 6 months and 2 years of age, fasting challenges were conducted and target tissues were collected at autopsy. LG-UN caused adult hyperthyroidism associated with increased thyroid expression of genes regulating TH synthesis and deiodination. In one or more of the target tissues, liver, cardiac muscle, and longissimus dorsi muscle, gene expressions were increased by LG-UN for TH receptors (THRA and THRB) and deiodinases but were decreased in visceral and subcutaneous adipose tissues. EL-ON increased TH levels in adolescent lambs, but this was reversed after diet correction and not evident in adulthood. We conclude that LG-UN programed TH axis function at the secretory level and differentially in target tissues, which was increasingly manifested with age. Differential TH signaling in adipose vs other tissues may be part of a mechanism whereby fetal malnutrition can predispose for obesity and other metabolic disorders.
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