Children who received little care showed slower epigenetic aging that could cause delays in their development.
As happens in other mammals, such as rats or macaques, the proper social and cognitive development of human babies depends on physical contact with their mothers or caregivers. Children raised in orphanages, where they are used to receiving little attention, show delayed growth, high-stress levels and behavioral disorders. However, it is not known whether affective stimuli or their absence, can affect children at the molecular level.
Epigenetic ageing and its effect
Now, a group of researchers from the University of British Columbia and British Columbia Children’s Hospital (see in Neuroscience), in collaboration with the University of California, San Francisco and the Canadian Institute for Advanced Research, have examined the relationship between the physical contact received at early ages and DNA methylation. This epigenetic modification marks certain parts of the chromosomes with molecules that act as switches and control the activity of each gene, but without altering the information contained therein. Over the years, these signals accumulate and allow the age of an organ or tissue to be determined. According to the study results, children who received little care showed slower epigenetic aging that could cause delays in their development. Moreover, changes were also observed in the methylation pattern of some genes.
The study, published in the journal Development and Psychopathology, looked at 94 healthy children living in British Columbia (Canada). The researchers asked their parents to monitor the behavior (how they cried, slept or fed) of their 5-week-old infants. They also noted the time they spent with their children and gave them physical contact. When the children were 4 years old, the scientists took DNA samples by swabbing the inside of their cheeks.
The analysis showed differences between children who received a large amount of physical contact and those who did not. Specifically, the researchers observed
- differences in the methylation pattern of five specific DNA sites. Two of these were particularly relevant because they
- affect genes related to the immune system and metabolism. Moreover,
- the “epigenetic age” was lower than expected in babies who experienced higher distress and received little contact. The way in which these epigenetic changes affect the development and health of the children remains unknown, although it is believed that the consequences could be harmful.
The desire of the researchers is to continue with their study because, if confirmed, their findings could help the most underprivileged children to receive better care.