Background: Cell-free DNA is detectable in the circulation. Increased cell-free DNA has been detected in cancer patients and individuals with trauma. We want to know whether patients with myocardial infarction (MI) also have increased cell-free DNA in their blood.
Methods: We used a QIAamp blood kit for DNA extraction from serum and the PicoGreen DNA kit for quantification. DNA patterns of serum DNA were established by gel electrophoresis on 2.5% metarphor gel.
Results: The average serum DNA in MI patients (N=55) was 511+/-398 ng/ml, more than 10-fold higher than normal (36.3+/-23.8 ng/ml, n=274). Patients with increased CK-MB (>4%) were associated with highly increased concentrations of cell-free DNA (93.4%). There was no correlation between the concentration of cell-free DNA and the concentrations of CK-MB, troponin I and C-reactive protein. In serial specimens, we found that the cell-free DNA rose early, but peaked behind CK-MB. A slightly diffused DNA ladder could be found with pooled cell-free DNA from MI patients by electrophoresis with the smallest DNA band at only a few hundred base pairs.
Conclusions: Cell-free DNA in MI patients is increased in patients diagnosed with MI, and may complement troponin and CK-MB in a multiple marker test format.