Maternal perinatal undernutrition modifies lactose and serotranferrin in milk: relevance to the programming of metabolic diseases?

A close link between intrauterine growth restriction and development of chronic adult diseases such as obesity, diabetes, and hypertension has been established both in humans and animals. Modification of growth velocity during the early postnatal period (i.e., lactation) may also sensitize to the development of metabolic syndrome in adulthood. This suggests that milk composition may have long-lasting programming/deprogramming metabolic effects in the offspring. We therefore assess the effects of maternal perinatal denutrition on breast milk composition in a food-restricted 50% (FR50) rat model. Monosaccharides and fatty acids were characterized by gas chromatography, and proteins were profiled by surface-enhanced laser desorption/ionization-time-of-flight analysis in milk samples from FR50 and control rat dams. Milk analysis of FR50 rats demonstrated that maternal undernutrition decreases lactose concentration and modulates lipid profile at postnatal day 10 by increasing the unsaturated fatty acids/saturated fatty acids and diminishes serotransferrin levels at postnatal day 21. Our data indicate that maternal perinatal undernutrition modifies milk composition both quantitatively and qualitatively. These modifications by maternal nutrition open new perspectives to identify molecules that could be used in artificial milk to protect from the subsequent development of metabolic diseases.

Perinatal nutrition programs the hypothalamic melanocortin system in offspring.

Epidemiological studies initially suggested that maternal undernutrition leading to low birth weight may predispose for long-lasting energy balance disorders. High birth weight due to maternal obesity or diabetes, inappropriate early postnatal nutrition, and rapid catch-up growth, may also sensitize to increased risk of obesity. As stated by the Developmental Origin of Health and Disease concept, the perinatal perturbation of fetus/neonate nutrient supply might be a crucial determinant of individual programming of body weight set-point. The hypothalamic melanocortin system composed of the melanocortin receptor 4, its agonist α-melanin-stimulating hormone (α-MSH), and its antagonist agouti-related protein (AgRP) is considered as the main central anorexigenic pathway controlling energy homeostasis. Studies in numerous animal models demonstrated that this system is a prime target of developmental programming by maternal nutritional manipulation. In rodents, the perinatal period of life corresponds largely to the period of brain maturation (i. e., melanocortin neuronal differentiation and development of their neural projections). In contrast, these phenomena essentially take place before birth in bigger mammals. Despite these different developmental time windows, altricial and precocial species share several common offspring programming mechanisms. Offspring from malnourished dams present a hypothalamic melanocortin system with a series of alterations: impaired neurogenesis and neuronal functionality, disorganization of feeding pathways, modified glucose sensing, and leptin/insulin resistance. Overall, these alterations may account for the long-lasting dysregulation of energy balance and obesity. Following maternal malnutrition, hormonal and epigenetic mechanisms might be responsible for melanocortin system programming in offspring.

Short- and long-term effects of maternal perinatal undernutrition are lowered by cross-fostering during lactation in the male rat.

Undernutrition exposure during the perinatal period reduces the growth kinetic of the offspring and sensitizes it to the development of chronic adult metabolic diseases both in animals and in humans. Previous studies have demonstrated that a 50% maternal food restriction performed during the last week of gestation and during lactation has both short- and long-term consequences in the male rat offspring. Pups from undernourished mothers present a decreased intrauterine (IUGR) and extrauterine growth restriction. This is associated with a drastic reduction in their leptin plasma levels during lactation, and exhibit programming of their stress neuroendocrine systems (corticotroph axis and sympatho-adrenal system) in adulthood. In this study, we report that perinatally undernourished 6-month-old adult animals demonstrated increased leptinemia (at PND200), blood pressure (at PND180), food intake (from PND28 to PND168), locomotor activity (PND187) and altered regulation of glycemia (PND193). Cross-fostering experiments indicate that these alterations were prevented in IUGR offspring nursed by control mothers during lactation. Interestingly, the nutritional status of mothers during lactation (ad libitum feeding v. undernutrition) dictates the leptin plasma levels in pups, consistent with decreased leptin concentration in the milk of mothers subjected to perinatal undernutrition. As it has been reported that postnatal leptin levels in rodent neonates may have long-term metabolic consequences, restoration of plasma leptin levels in pups during lactation may contribute to the beneficial effects of cross-fostering IUGR offspring to control mothers. Collectively, our data suggest that modification of milk components may offer new therapeutic perspectives to prevent the programming of adult diseases in offspring from perinatally undernourished mothers.