Fathers who are under psychological stress could pass on an increased risk of Type 2 diabetes to their kids, a new mice study has found.
Scientists from the Shanghai Jiao Tong University School of Medicine have found that stress hormones result to epigenetic changes in sperm, giving the mice offspring high levels of blood sugar. To prevent this from happening, researchers said the father's stress hormones need to be blocked.
The Shanghai team confined several male mice in plastic tubes for two hours a day in a span of two weeks to stimulate stress.
After doing so, the mice's glucose levels were increased. The animals also gained weight more slowly and had elevated levels of glucocorticoids -- the stress hormones -- in their blood.
The mice were then mated with female mice which had not been confined. Their offspring had higher levels of glucose than normal, researchers said.
"Paternal psychological stress can result in hyperglycemia in offspring in mice," said Professor Xiaoying Li, one of the researchers of the study.
According to Li, the root of the spike in glucose levels was in a gene called Sfmbt2.
When the mouse father is immobilized daily, the high glucocorticoids levels results to extra methyl groups being added to the Sfmbt2 gene in the mouse's sperm.
The additional methyl groups do not affect the core DNA, but they do control how Sfmbt2 an associated microRNA are expressed.
The epigenetic change due to stress, through glucocorticoids, was surprising, scientists said. The epigenetic change from stressed fathers was displayed in the livers of their offspring. The particular microRNA is meant to control the PEPCK enzyme which regulates sugar production in the liver.
During mammalian reproduction, the Sfmbt2 gene is turned off in the mother's egg. The offspring only inherits the copy of the gene from the father's sperm.
When the only Sfmbt2 gene carries epigenetic changes, the particular microRNA is silenced and is unable to regulate PEPCK as it typically would.
The offspring would develop a liver with too much PEPCK, and their levels of blood glucose would increase.
Although the study was tested on mice, researchers believe the findings can apply to humans as well.
"It is potentially possible for our study to be translated into the treatment of hyperglycemia in human beings in the future," added Li.
The findings of the study are featured in the journal Cell Metabolism.
Photo: Christian Scheja | Flickr