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University Of São Paulo Study Shows Exposure To Adverse Environment Can Have Negative Effects On Embryonic Development

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Research published in the scientific journal Proceedings of the National Academy of Sciences (PNAS) , last year, revealed that the aging process is directly linked to fetal programming, which are the changes that occur in the fetus still in its development period due to the environment in which the mother, while pregnant, is inserted.

From analyzes of blood samples from elderly people over 70 years old, researchers Lauren L. Schmitz and Valentina Duque found that, specifically, the period of the Great Depression in the United States had an impact on the regulation of cellular and molecular processes, which caused a change in epigenetic function.

“The epigenome is nothing more than signals that exist in the DNA that can modify the way in which this DNA is expressed. So, through these epigenetic modifications of our DNA, it can be turned on or off under certain circumstances”, explains Gabriela Placoná Diniz, Ph.D. and assistant professor in the Department of Anatomy at the Institute of Biomedical Sciences at USP.

This means that, depending on the change in the epigenetic function, certain characteristics may be expressed more clearly. Gabriela clarifies that “what they showed in this study is that children of mothers who were subjected to economic conditions at the time of the American Great Depression had an increase in epigenetic markers associated with accelerated aging in adulthood”. Thus, they age faster than other people.

The situation of the intrauterine environment ends up causing an alteration known in humans as DNA methylation. The genetic sequence is maintained and what happens is the methylation (addition of a methyl) of a nucleotide, the cytokine. “These modifications can alter the process of cell division and DNA transcription, leading to alterations in the expression of certain genes that are responsible for the production of some proteins that are important for the functioning of the organism, for the aging process, metabolism and even the prognosis of possible future illnesses”, explains Joel Rennó, professor at the Department of Psychiatry at the USP School of Medicine and director of the Women’s Mental Health Program (ProMulher) at IP-USP.

Normally, fetal programming can only be noticed in adulthood. It is not possible to identify structural changes in the development of the fetus while still pregnant, which in theory makes it impossible to take preventive measures in relation to the health of the fetus.

The Great Depression Is Not the Only Factor
Exposure to socioeconomic factors is not solely responsible for epigenetic changes in fetal programming. According to Rennó, “they can happen due to intrauterine exposure to malnutrition, infectious processes and stressful events, such as, for example, pregnant mothers who were somehow subjected to situations such as the crash of the New York Stock Exchange in the 1930s, tragic situations , or other moments, such as 9/11 and the Holocaust”.

Exposure to adverse events during pregnancy is also more likely to alter the time of organogenesis, which is the process of organ formation. There is also a more sensitive period of development of the fetus, which, when exposed to intrauterine and extrauterine adverse events, generates long-term consequences.

“These changes can lead to some alterations, whether in the clinical sphere, including a more accelerated senescence process or not, and also to greater vulnerability to future psychological and psychiatric conditions. Women who go through situations of violence during pregnancy, socioeconomic deprivation, malnutrition, women who are more vulnerable to infections and other stressful triggers may, somehow, due to this genetic mechanism, have children who, in adulthood, are more susceptible to conditions psychiatric conditions or even some clinical diseases”, explains the doctor.

Another aspect remembered by Rennó is that of behavioral modeling, which occurs in the interaction between parents and children. It is not necessarily associated with genetics, but has to do with the fact that children witness certain behaviors from their parents, such as phobic avoidance, anticipatory anxiety or a routine with a high flow of activities and information that do not match the capacity of that child. “A depressed mother or an anxious mother – who has certain behaviors or habits resulting from anxiety or depression – can, in the mother-baby bond, influence the child’s behavior and habits”, she exemplifies.

How can we get around this situation?
The causes of death found in the elderly – born shortly after the crash of the New York Stock Exchange – who participated in the study were mainly due to metabolic disorders, linked to the interruption of intrauterine growth.

At that time, there were no public policies that minimized the impacts of this economic recession on vulnerable mothers. There were also no prenatal care or vitamins for pregnant women, that is, this care was not taken and all the stress was felt without any pre-, during or post-pregnancy care.

Gabriela Diniz complements, saying that the way to prevent this problem from happening again, or these markers intensifying their presence, would be “to develop policies that are able to minimize the financial difficulties that many mothers go through today and that can not only affect the health them, but also the health of the babies”.