Genetic basis, nutritional challenges and adaptive responses in the prenatal origin of obesity and type-2 diabetes.

Obesity and type-2 diabetes are currently considered global pandemics. A large set of epidemiological evidences are addressing both the importance of a genetic predisposition -starting with the thrifty genotype hypothesis- and the determinant role of the maternal nutrition during pregnancy -starting with longitudinal studies of individuals born during the Dutch famine- on the adult onset of the disease. Compelling evidences suggest that both over- and undernutrition may modify the intrauterine environment of the conceptus and may alter the expression of its genome, predisposing to disease in the adult life. However, the most recent data indicate that the consequences of this phenomenon, termed as prenatal programming, are influenced both by timing, degree and duration of the challenge and by the adaptive response of the mother and the conceptus; thus, the information acquired by interventional studies modifying these parameters is becoming increasingly important. Obviously, interventional research in human beings is limited by ethical issues; hence, investigations need to be conducted on animal models, either rodents or large animals. This review summarizes the results of epidemiological human studies and translational animal research in unraveling the interaction between genome, nutritional status and adaptive response on the establishment of postnatal obesity, insulin resistance and type-2 diabetes.