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 Impact of maternal high-fat diet and early stress on the long lasting effects on adult phenotype

Thesis supervisor: Pr. Muriel Darnaudéry

Jury:

Dr Sophie Layé,  INRA,Bordeaux, President

Dr Valérie Daugé,  INRA, Jouy en Josas, Rapportrice

Pr Stefania Maccari, CNRS, Université Lille1,  Lille, Rapportrice

Pr Vassilia Théodorou, INRA, Ecole d’ingénieur de Purpan, Toulouse, Examinatrice

Dr Susanna Pietropaolo, CNRS, INCIA, Bordeaux, Examinatrice

Pr Muriel Darnaudéry, INRA, Université de Bordeaux, Bordeaux, Thesis supervisor

 ABSTRACT

The perinatal period is a critical period during which the quality of the environment has long lasting effects on adult phenotype. Early adversity in childhood has been associated with higher risks to develop neuropsychiatric disorders later in life. Nowadays, modern societies are characterized by a high consumption of fat. Although these changes also affect nutritional environment during development, the impact on brain functioning and behavior remains unknown.
The aim of my thesis was to examine the programming effects of maternal high-fat diet (HFD, western diet) and early stress on offspring phenotype. In the first part, we showed that maternal HFD leads to metabolic disturbances in adult offspring and sensitized to memory deficits if the HFD is maintained throughout life. In the second part, we explored the effects of the combination between maternal HFD and chronic maternal separation (3h/day, postnatal day 2 to 14). Maternal separation enhances motivation for palatable food and combined with maternal HFD exacerbates vulnerability to diet-induced obesity. In contrast, maternal HFD protects the offspring against the emotional and cognitive impairments induced by maternal separation.
This protective effect of maternal HFD could be related to the increase of maternal care in stressed dams exposed to HFD and to the attenuation of neurodevelopmental alterations in the prefrontal cortex of stressed pups. In conclusion, my work demonstrates that stress and nutrition during early life interact and influence later adult phenotype.
Keywords : motivation, metabolism, emotion, memory