A Heart Attack May Leave Long-Lasting Epigenetic Marks on DNA

A heart attack could leave behind more than just physical damage, according to a new study. Suffering from myocardial infarction, or a heart attack, may lead to the storage of epigenetic marks on certain genes. Researchers from Uppsala University reported in Human Molecular Genetics that an epigenetic “memory” of a heart attack may stick around on DNA long after the heart attack occurred.

Both the environment and genetics can determine whether someone is more or less susceptible to cardiovascular disease. Once we inherit our genes from our parents, our environment can actually influence the expression of various genes, turning them “on” or “off” via epigenetic mechanisms. These changes can have positive effects, but, if gone awry, the epigenetic marks can lead to disease.

The Swedish researcher who led the study, Åsa Johansson, from the Department of Immunology, Genetics and Pathology at Uppsala University, said, “During a heart attack the body signals by activating certain genes. This mechanism protects the tissue during the acute phase of the disease, and restores the body after the heart attack.” He believes it is likely, then, that epigenetic changes associated with a heart attack also occur.

The team performed an epigenome-wide association study (EWAS) and found that numerous epigenetic changes actually do occur to the DNA of people who experience a heart attack. DNA methylation, one of the most well-known epigenetic tags, was analyzed and compared in a group of over 700 participants.

“We have shown that individuals with a history of [heart attacks] have a deviating pattern of DNA methylation at many genomic loci of which a large fraction has previously been linked to [cardiovascular diseases],” reported the researchers. They found 192 genes to be differentially methylated, with many of these marks located on genes connected to cardiovascular disease and cardiac function.

The researchers were not able to conclude whether these epigenetic differences led to the disease or if they were formed as a result of the heart attack and were sustained as “molecular memory.” Regardless, the researchers have highlighted genes that may be important to understanding the onset of and recovery from heart attacks. In addition, the various sites they identified might serve as potential biomarkers.

Interestingly, previous evidence supports the possibility that epigenetic marks may be transmitted across generations. Some studies indicate that epigenetic “memory” of nutrition may be passed down from a grandmother to her grandchild or that a father’s early life experiences could epigenetically influence his child’s health. Could these tags be inherited by the children of an individual who experienced a heart attack and might this increase their susceptibility to cardiovascular disease? Although further research is needed, these results pose interesting questions into the persistence of epigenetic marks and their potential long-lasting impact.

The group of researchers hopes that their results may offer new insight into the epigenetic changes that take place when someone experiences a heart attack. Their findings could eventually help design new drugs and improve treatment.

Source: Rask-Andersen, M., Martinsson, D., Ahsan, M., Enroth, S., Ek, W.E., Gyllensten, U., Johansson, Å. (2016). Epigenome Wide Association Study Reveals Differential DNA Methylation in Individuals With a History of Myocardial Infarction. Human Molecular Genetics.

Reference: Uppsala Universitet. The memory of a heart attack is stored in our genes. AlphaGalileo. 16 Sep 2016. Web.