Washington D.C: A study finds that not all the people have a permanent heart muscle loss after a heart attack.
In the study, Michaela Patterson and her colleagues focused on a regenerative type of heart muscle cell called a mononuclear diploid cardiomyocyte (MNDCM). Zebrafish and newborn mammals, including mice and humans, have large numbers of MNDCMs and a relatively a power to regenerate heart muscle. However, adult mammals have few MNDCMs and a correspondingly limited capacity for regeneration after an injury such as a heart attack.
Patterson and her co-authors observed a surprising amount of alterations in the number of MNDCMs among different strains of adult mice. In some strains, MNDCMs accounted for only 1.9 percent of heart muscle cells. In others, a full 10 percent were MNDCMs. As expected, the higher the percentage of MNDCMs, the better the mice fared in regenerating their heart muscle after injury.
“This was an exciting finding, which suggests, not all individuals are destined to permanent heart muscle loss after a heart attack, but rather some can naturally recover both heart muscle mass and function. If we can identify the genes that make some individuals better at it than others, then perhaps we can stimulate regeneration across the board,” said Patterson.
By conducting a genome-wide association study, the researchers have found one of the key genes underlying this variation: Tnni3k. By blocking this gene in mice, the researchers were able to produce higher percentages of MNDCMs and enhanced heart regeneration. In contrast, activating this gene in zebrafish decreased MNDCMs and impaired heart regeneration.
Senior author Sucov described how this early discovery could be the first step towards a preventive strategy to mitigate heart disease, the leading cause of death in the Western world.
“The activity of this gene, Tnni3k, can be modulated by small molecules, which could be developed into prescription drugs in the future,” he said.
-With agency’s inputs