Stress can impact brain development in offspring

Is too much worry over Covid-19 getting better of you? And if you are a man in reproductive age and planning a baby, it can have an impact on your future offspring too.

A study by researchers from the University of Maryland School of Medicine appeared in the journal Nature Communications on last Friday has shown that prolonged fear and anxiety, brought on by major stressful events like the current coronavirus pandemic, can not only take a toll on a man’s mental health, but can also have a lasting impact on his sperm composition, affecting brain development of his future progenies.

The research, led by Tracy Bale, a professor of pharmacology and Director of the Center for Epigenetic Research in Child Health & Brain Development at the university, outlines a biological mechanism for how a father's experience with stress can influence fetal brain development in the womb.

What does the research say ?

The team which included a couple of researchers of Indian descent found that the effects of paternal stress can transmitted to offspring through changes in the extracellular vesicles that then interact with maturing sperm. Extracellular vesicles are small membrane-bound particles that transport proteins, lipids and nucleic acids between cells. They are produced in copious amounts in reproductive tract and play an integral role in sperm maturation.

"There are so many reasons that reducing stress is beneficial especially now when our stress levels are chronically elevated and will remain so for the next few months," said Bale in a statement. "Properly managing stress can not only improve mental health and other stress-related ailments, but it can also help reduce the potential lasting impact on the reproductive system that could impact future generations," she said.

The team clarified that it did not specifically study those who were under stress due to the coronavirus pandemic.

Process

To examine a novel biological role for extracellular vesicles in transferring dad's stress to sperm, the researchers examined extracellular vesicles from mice following treatment with the stress hormone corticosterone. After treatment, the extracellular vesicles showed dramatic changes in their overall size as well as their protein and small RNA content.

When sperm were incubated with these previously "stressed" extracellular vesicles prior to fertilising an egg, the resulting mouse pups showed significant changes in patterns of early brain development, and as adults these mice were also significantly different than controls for how they responded to stress themselves.

The scientists who independently analysed sperm from young people with elevated levels of stress found significant changes in the small RNA content of their sperm, similar to that found in the mouse study.

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