A method for the non-invasive and cell-specific detection of cardiomyocyte (cardiac muscle cell) death is presented in Nature Communications this week. The method involves the measurement of circulating cell-free DNA released from dying cardiomyocytes. Potential applications could include the diagnosis and monitoring of cardiac pathologies associated with cellular death, such as myocardial infarction (heart attack) and sepsis.
Yuval Dor and colleagues identify a methylation signature in the DNA of human cardiomyocytes and develop an assay to measure it in the blood. The assay can diagnose patients who have suffered a heart attack with high sensitivity and specificity, with a performance similar to that when detecting levels of the protein troponin in the blood: the current clinical gold standard for detecting heart-tissue damage. The levels of the cardiac specific cell-free DNA marker are strongly increased in the plasma of septic patients, suggesting that massive cardiomyocyte death occurs in these subjects. Compared to troponin, this newly identified marker is a stronger predictor of short-term mortality due to sepsis.
Although the link between circulating cell-free DNA and cell death has to be conclusively demonstrated, the authors suggest that this newly developed assay might complement known biomarkers of cardiac injury and help clinicians to discriminate cardiac cell death from reversible cellular injury.