Researchers from the University of Southern Denmark and the State University of Campinas have determined that a predisposition to obesity and related metabolic disorders can be passed from father to child via sperm. The findings of this study are published in the journal Nature Communications (NatCom).
During their experiments, the scientists examined the impact of obesity in male mice on the health of their offspring. It was discovered that the pups were born at a normal weight and did not outwardly differ from the control group. However, after a few months, metabolic disturbances began to emerge in them — glucose intolerance and insulin resistance, which are considered “harbingers” of type 2 diabetes. These changes were particularly pronounced in the male offspring.
The authors of the study termed this condition “hidden metabolic dysfunction,” as no outward signs of obesity were observed in the offspring. According to the researchers, this indicates that the consequences of parental obesity may not manifest immediately and are not necessarily accompanied by excess weight.
MicroRNAs, small molecules that regulate gene activity, play a crucial role in the mechanism of transmitting these disorders. In obese male mice, scientists identified elevated levels of microRNAs let-7d and let-7e in their adipose tissue and sperm. During fertilization, these molecules entered the embryo and suppressed the production of the enzyme DICER, which is essential for the maturation of other microRNAs and the proper regulation of genes.
A deficiency in DICER led to impaired function of mitochondria — cellular structures responsible for energy production. Consequently, the offspring experienced altered metabolism in their adipose tissue, increasing their risk of developing metabolic diseases in adulthood.
The researchers do note, however, that the identified changes are not irreversible. After the male mice lost weight, no adverse effects were observed in their offspring. The scientists obtained similar results when analyzing human data, but further research is necessary for definitive confirmation.
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