Maternal obesity causes fetal hypothalamic insulin resistance and disrupts development of hypothalamic feeding pathways.

OBJECTIVE: Perinatal exposure to maternal obesity results in predisposition of offspring to develop obesity later in life. Increased weight gain in offspring exposed to maternal obesity is usually associated with hyperphagia, implicating altered central regulation of food intake as a cause. We aimed to define how maternal obesity impacts early development of the hypothalamus to program lasting dysfunction in feeding regulatory pathways. METHODS: Mice offspring of diet-induced obese mothers were compared to the offspring of lean control mothers. We analysed gene expression in the fetal hypothalamus, alongside neurosphere assays to investigate the effects of maternal obesity on neural progenitor cell proliferation in vitro. Western blotting was used to investigate the insulin signalling pathway in the fetal hypothalamus. Characterisation of cell type and neuropeptide profile in adulthood was linked with analyses of feeding behaviour. RESULTS: There was a reduction in the expression of proliferative genes in the fetal hypothalamus of offspring exposed to maternal obesity. This reduction in proliferation was maintained in vitro when hypothalamic neural progenitor cells were grown as neurospheres. Hypothalamic fetal gene expression and neurosphere growth correlated with maternal body weight and insulin levels. Foetuses of obese mothers showed hypothalamic insulin resistance, which may be causative of reduced proliferation. Furthermore, maternal obesity activated the Notch signalling pathway in neonatal offspring hypothalamus, resulting in decreased neurogenesis. Adult offspring of obese mothers displayed an altered ratio of anorexigenic and orexigenic signals in the arcuate nucleus, associated with an inability to maintain energy homeostasis when metabolically challenged. CONCLUSIONS: These findings show that maternal obesity alters the molecular signature in the developing hypothalamus, which is associated with disrupted growth and development of hypothalamic precursor cells and defective feeding regulation in adulthood. This is the first report of fetal hypothalamic insulin resistance in an obese pregnancy and suggests a mechanism by which maternal obesity causes permanent changes to hypothalamic structure and function.

Long-term effects of a maternal high-fat: high-fructose diet on offspring growth and metabolism and impact of maternal taurine supplementation.

OBJECTIVE: Maternal obesity is associated with obesity and metabolic disorders in offspring. However, there remains a paucity of data on strategies to reverse the effects of maternal obesity on maternal and offspring health. With maternal undernutrition, taurine supplementation improves outcomes in offspring mediated in part via improved glucose-insulin homeostasis. The efficacy of taurine supplementation in the setting of maternal obesity on health and well-being of offspring is unknown. We examined the effects of taurine supplementation on outcomes related to growth and metabolism in offspring in a rat model of maternal obesity. DESIGN: Wistar rats were randomised to: 1) control diet during pregnancy and lactation (CON); 2) CON with 1.5% taurine in drinking water (CT); 3) maternal obesogenic diet (MO); or 4) MO with taurine (MOT). Offspring were weaned onto the control diet for the remainder of the study. RESULTS: At day 150, offspring body weights and adipose tissue weights were increased in MO groups compared to CON. Adipose tissue weights were reduced in MOT versus MO males but not females. Plasma fasting leptin and insulin were increased in MO offspring groups but were not altered by maternal taurine supplementation. Plasma homocysteine concentrations were reduced in all maternal taurine-supplemented offspring groups. There were significant interactions across maternal diet, taurine supplementation and sex for response to an oral glucose tolerance test , a high-fat dietary preference test and pubertal onset in offspring. CONCLUSIONS: These results demonstrate that maternal taurine supplementation can partially ameliorate adverse developmental programming effects in offspring in a sex-specific manner.

Children Exposed to Maternal Obesity or Gestational Diabetes Mellitus During Early Fetal Development Have Hypothalamic Alterations That Predict Future Weight Gain.

OBJECTIVE: Exposure in utero to maternal obesity or gestational diabetes mellitus (GDM) is linked to a high risk for obesity in offspring. Animal studies suggest that these exposures disrupt the development of the hypothalamus, a brain region that regulates body weight, predisposing offspring to develop obesity. This study tested the hypothesis in humans that in utero exposure to maternal obesity and/or GDM is associated with alterations in the hypothalamic response to glucose and the altered hypothalamic response would predict greater increases in child adiposity 1 year later. RESEARCH DESIGN AND METHODS: Participants were 91 children aged 7-11 years with and without in utero exposure to GDM. Maternal prepregnancy BMI and GDM exposures were determined from electronic medical records. Arterial spin labeling MRI was used to determine the child's hypothalamic blood flow response to oral glucose. Anthropometric measures were acquired in all children at their initial visit and again 1 year later in a subset of 44 children. RESULTS: Children exposed to GDM diagnosed at ≤26 weeks' gestation had increased hypothalamic blood flow (a marker of hypothalamic activation) in response to glucose when compared with unexposed children, and results remained after adjustments for child age, sex, BMI, and maternal prepregnancy BMI. Maternal prepregnancy BMI was positively associated with the child's hypothalamic response to glucose. Greater hypothalamic response to glucose predicted greater increases in child's BMI 1 year later. CONCLUSIONS: Increased glucose-linked hypothalamic activation during childhood represents a possible mechanism by which exposure to maternal metabolic disorders during fetal development increases future risk for obesity.