Brain development of the unborn baby: a combined effect of genetics and food availability

Newswise — A new population study led by researcher Tomas Paus , professor of psychiatry and neuroscience at the University of Montreal and researcher at CHU Sainte-Justine, highlights the respective roles of maternal and fetal genes in the growth of the baby's cerebral cortex . The research team's results , published in the prestigious journal Nature Communications , demonstrate that genetic variants associated with higher birth weight are also associated with better growth of the cortex. However, the abundance or lack of food appears to influence the relative importance of the role played by these genes.

Genes that make the baby grow… and his brain

With postdoctoral fellow Daniel Vosberg, first author of the article, Tomas Paus analyzed data on birth weight and brain magnetic resonance imaging of several thousand individuals included in the UK Biobank, a database of biomedical data in the United Kingdom. These analyzes confirmed that a higher birth weight is associated with a larger size of the cortex (measured by its surface area).

In addition, it appears that the genetic variants present in the mother and in the baby which are associated with weight are also associated with the cortical surface. Thus, in the baby, the genes linked to the action of insulin are decisive, whereas, in the mother, the genetic variants favorable to the elimination of toxins at the cellular level play a major role.

Diet incidence and intergenerational transmission

The two groups of genetic variants are not always equally important in determining cortex size. “By comparing data by year of birth and through statistical modeling and analysis of interactions at the cellular level, we shed light on the epigenetic role of exposure to dietary restrictions during gestation or early childhood” , explains Tomas Paus.

In people exposed to dietary restrictions (during World War II), maternal detoxification genes have the greatest influence on cortex growth. This characteristic seems to be transmitted from one generation to the next, since the association is also observable in the children of people who were exposed to significant dietary restrictions during the war. In others, the growth of the cortex is mainly associated with genes related to the action of insulin in the fetus.

Analyzes indicate that genes that counter the negative effects of dietary restrictions, particularly in terms of cellular stress and immune activation, are very important. “During periods of famine, when cells multiply, there is a much greater risk of errors,” specifies the researcher. This could explain why, in such a context, it is the genes responsible for DNA repair which are decisive for the baby's brain growth.

Promote brain growth from the earliest stages of life

Now that we better understand the links between low birth weight and brain growth, and the importance of starvation as a mediating factor, the next step is to evaluate the optimal method for promoting cortex growth after birth . “With Dr. Thuy Mai Luu from CHU Sainte ^-  Justine, we will soon launch a pilot project aimed at determining the best support for low-weight babies for optimal brain development,” rejoices Tomas Paus.

About the study

The article “ Intrauterine growth and the tangential expansion of the human cerebral cortex in times of food scarcity and abundance ,” by Daniel E. Vosberg and colleagues, is published in the journal Nature Communications (electronic publication).