Stress in early ontogenesis as an adaptive phenomenon
In biomedical science, the effects of stress in early life (prenatal and early postnatal) are in most cases considered as negative for the individual, causing disorders in the development of reproductive functions, immune, neuroendocrine systems, brain and behavior, including cognitive abilities and persistent mental disorders. Against this background, research is gaining strength, discussing the consequences of early stresses from the standpoint of their possible adaptive value, estimated as an increase in fitness in the current and subsequent generations. The review gives a brief description of the main mechanisms of the ontogenetic programming of the descendant organism, caused by maternally derived stress. The main attention is paid to experiments in nature or to experiments modeling the natural situation in which the effects of maternal stresses on descendants were investigated in some vertebrate species, from teleost fishes to mammals. Consequences of early stresses, phenotypically manifested in offspring, are adaptive in those cases when the environmental conditions (including social), under which the mother’s organism existed during the egg formation or pregnancy and immediately after the birth of the brood/ litter, correspond to the conditions of offspring’s future life. For the mother, effects of the stress transmitted to the offspring can be beneficial, since they optimize the costs of current reproduction, and ultimately can increase mother’s inclusive fitness, regardless of whether they increase or decrease the fitness of offspring in the short term. An evolutionary-ecological approach to studying the consequences of early stress can be useful for understanding Developmental Origins of Health and Disease (DOHaD). The data on vertebrate species accumulated today give hope that an understanding of the need to reduce the inconsistency between the prenatal and the future environment of a person’s life, a mismatch that significantly increases the risks of diseases in adulthood, will finally be reached.