Impact of perinatal exposure to high-fat diet and stress on responses to nutritional challenges, food-motivated behaviour and mesolimbic dopamine function.

BACKGROUND/OBJECTIVES: Energy-dense food exposure and stress during development have been suggested to contribute to obesity and metabolic disorders later in life. Although these factors are frequently associated, the effects of their combination have not yet been investigated. In this study, using an animal model, we examined the long-term impact of maternal high-fat diet (HFD) and early-life stress (ELS) on energy homoeostasis control and food motivation. METHODS: Body weight growth under HFD, adipose tissue, body weight control in response to fasting and refeeding, food-motivated behaviour and mesolimbic dopamine function were examined in adult male offspring exposed to maternal HFD (during gestation and lactation) and/or ELS (maternal separation 3 h per day from postnatal day 2 to 14). RESULTS: Maternal HFD or ELS alone had no significant effect on offspring body weight; however, the combination of these factors exacerbated body weight gain when animals were exposed to HFD after weaning. There are no other significant combinatory effects of these perinatal events. In contrast, independently of the maternal diet, ELS disrupted body weight control during a fasting-refeeding procedure, increased adipose tissue mass and altered lipid metabolism. Finally, maternal HFD and ELS both resulted in exacerbated food-motivated behaviour and blunted dopamine release in the nucleus accumbens during palatable food consumption. CONCLUSIONS: We report a synergistic effect of perinatal HFD exposure and stress on the susceptibility to gain weight under HFD. However, ELS has a stronger impact than maternal HFD exposure on energy homoeostasis and food motivation in adult offspring. Altogether, our results suggest a programming effect of stress and nutrition supporting the hypothesis of the developmental origin of health and disease.

Maternal high-fat diet prevents developmental programming by early-life stress.

Anxiety disorders and depression are well-documented in subjects exposed to adverse childhood events. Recently, maternal obesity and/or maternal consumption of high-fat diets (HFD) have been also proposed as risk factors for offspring mental health. Here using an animal model in rats, we explored the combinatorial effects of a maternal HFD (40% of energy from fat without impact on maternal weight; during gestation and lactation) and maternal separation (MS) in offspring. In the prefrontal cortex (PFC) of pups, MS led to changes in the expression of several genes such as Bdnf (brain derived neurotrophic factor), 5HT-r1a (serotonin receptor 1a) and Rest4 (neuron-restrictive silencer element, repressor element 1, silencing transcription factor (Rest), splicing variant 4). Surprisingly, perinatal HFD strongly attenuated the developmental alterations induced by MS. Furthermore, maternal HFD totally prevented the endophenotypes (anxiety, spatial memory, social behavior, hypothalamic-pituitary-adrenal (HPA) axis response to stress, hippocampal neurogenesis and visceral pain) associated with MS at adulthood. Finally, we also demonstrated that HFD intake reduced anxiety and enhanced maternal care in stressed dams. Overall, our data suggest that a HFD restricted to gestation and lactation, which did not lead to overweight in dams, had limited effects in unstressed offspring, highlighting the role of maternal obesity, rather than fat exposure per se, on brain vulnerability during development.