ABNORMALLY short telomeres in the heart muscle cells (cardiomyocytes) of cardiomyopathy patients have been found by researchers from Stanford University, California, USA, providing new insights into the condition. It is hoped the findings will help healthcare professionals to identify individuals at risk of heart failure due to cardiomyopathy early, as well as lead to the development of new treatments.
The study built on previous research showing that people with Duchenne muscular dystrophy, who often die from heart failure at an early age, have short telomeres in the DNA of their cardiomyocytes. “The shortening of telomeres in cardiomyocytes appears to be a reliable hallmark of cardiac failures that arise due to genetic defects, and it’s very specific to cells that require the missing contractile proteins such as dystrophin, troponin T, or myosin heavy chain, among others,” explained Prof Helen Blau, Stanford University.
In their study, the team found that in 11 patients with dilated or hypertrophic cardiomyopathy due to genetic mutations, the cardiomyocyte telomere lengths were 25–40% shorter than in a control group composed of individuals who had died from causes unrelated to heart disease. There were no significant differences in the telomere lengths in the DNA of non-beating heart cells of the blood vessels between the groups.
They also observed that telomere shortening occurred in laboratory-grown cardiomyocytes within 20 days; these cardiomyocytes were created by induced pluripotent stem cells (iPS) generated from cardiomyopathy patients who had significantly shorter telomeres than their unaffected relatives.
The findings potentially provide the foundation for further research aimed at improving understanding of the underlying mechanisms and causes of cardiomyopathy, and ultimately the creation of new drugs that can reverse the disease; this should be made easier and quicker by the use of iPS cell technology.
“Now we can study this phenomenon in the lab in real time and start to ask questions about cause and effect,” commented Prof Blau. “We’d love to know, for example, how this shortening might impact the DNA damage response, mitochondrial dysfunction, and cell-death pathways. It opens up a whole new line of investigation.”
Cardiomyopathy, which is believed to affect one out of every 500–2,500 people worldwide, is a condition in which the heart’s ability to pump blood effectively is inhibited due to it being unusually large, thickened, or stiff.
James Coker, Reporter
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