Maternal prenatal undernutrition programs adipose tissue gene expression in adult male rat offspring under high-fat diet

Maternal calorie restriction modulates placental mitochondrial biogenesis and bioenergetic efficiency: putative involvement in fetoplacental growth defects in rats

Low birth weight is associated with an increased risk for developing type 2 diabetes and metabolic diseases. The placental capacity to supply nutrients and oxygen to the fetus represents the main determiner of fetal growth. However, few studies have investigated the effects of maternal diet on the placenta. We explored placental adaptive proteomic processes implicated in response to maternal undernutrition. Rat term placentas from 70% food-restricted (FR30) mothers were used for a proteomic screen. Placental mitochondrial functions were evaluated using molecular and functional approaches, and ATP production was measured. FR30 drastically reduced placental and fetal weights. FR30 placentas displayed 14 proteins that were differentially expressed, including several mitochondrial proteins. FR30 induced a marked increase in placental mtDNA content and changes in mitochondrial functions, including modulation of the expression of genes implicated in biogenesis and bioenergetic pathways. FR30 mitochondria showed higher oxygen consumption but failed to maintain their ATP production. Maternal undernutrition induces placental mitochondrial abnormalities. Although an increase in biogenesis and bioenergetic efficiency was noted, placental ATP level was reduced. Our data suggest that placental mitochondrial defects may be implicated in fetoplacental pathologies.

Adult glucose metabolism in extremely birthweight-discordant monozygotic twins

AIMS/HYPOTHESIS

Low birthweight (BW) is associated with increased risk of type 2 diabetes. We compared glucose metabolism in adult BW-discordant monozygotic (MZ) twins, thereby controlling for genetic factors and rearing environment.

METHODS

Among 77,885 twins in the Danish Twin Registry, 155 of the most BW-discordant MZ twin pairs (median BW difference 0.5 kg) were assessed using a 2 h oral glucose tolerance test with sampling of plasma (p-)glucose, insulin, C-peptide, glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1. HOMA for beta cell function (HOMA-β) and insulin resistance (HOMA-IR), and also insulin sensitivity index (BIGTT-SI) and acute insulin response (BIGTT-AIR), were calculated. Subgroup analyses were performed in those with: (1) double verification of BW difference; (2) difference in BW >0.5 kg; and (3) no overt metabolic disease (type 2 diabetes, hyperlipidaemia or thyroid disease).

RESULTS

No intra-pair differences in p-glucose, insulin, C-peptide, incretin hormones, HOMA-β, HOMA-IR or BIGTT-SI were identified. p-Glucose at 120 min was higher in the twins with the highest BW without metabolic disease, and BIGTT-AIR was higher in those with the highest BW although not in pairs with a BW difference of >0.5 kg.

CONCLUSIONS/INTERPRETATION

BW-discordant MZ twins provide no evidence for a detrimental effect of low BW on glucose metabolism in adulthood once genetic factors and rearing environment are controlled for.

Is the adipose tissue a key target of developmental programming of adult adiposity by maternal undernutrition?

Epidemiological studies have shown that maternal undernutrition during pregnancy (MU) leads to intrauterine growth retardation and low birth weight, and may predispose individuals to the development of metabolic syndrome symptoms later in life such as overweight. Some clues from a model of prenatal maternal 70% food-restricted diet throughout gestation in pregnant female rats (FR30) suggest that the white adipose tissue (WAT) is a key target of MU fetal programming. Under standard diet, although showing a lean phenotype, adult FR30 male rats were predisposed to adiposity exhibiting higher serum leptin and corticosterone concentration, two hormones actively involved in WAT regulation. Although FR30 procedure does not worsen the metabolic syndrome features induced by HF diet, FR30HF rats gained more weight and showed hyperleptinemia suggesting increased adiposity. WAT FR30 adult rats revealed marked changes in transcript levels of several genes. In particular, leptin and Ob-Rb, many peptide precursors and receptors, factors involved in lipogenesis and glucocorticoid sensitivity mRNA expression levels as well as mechanisms involved in leptin sensitivity, were modified in FR30 offspring in depot-specific and diet-specific manners. These modifications might predispose for altered fat accumulation in adult male rat offspring.