Perioperative plasma mitochondrial DNA dynamics and correlation with inflammation during infantile cardiopulmonary bypass

Here we report that mtDNA may participate in a systemic inflammatory response to CPB.

In the present study, we analyzed the perioperative plasma mtDNA and inflammatory cytokine levels of 48 infants undergoing ventricular septal defect closure. Blood samples were collected before aortic cross-clamping (T1), at the end of CPB (T2), and 6h (T3), 12h (T4), and 24h (T5) post-CPB. Reverse transcription-polymerase chain reaction and specific enzyme-linked immunosorbent assay were used to quantify the plasma mtDNA and inflammatory cytokines, respectively. Bivariate correlation analysis was used to determine the correlations between plasma mtDNA and inflammatory cytokines.

Numerous studies in animals and humans have demonstrated that inflammatory mediators such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 play a role in cardiopulmonary bypass (CPB), which might affect surgical outcomes. Plasma mitochondrial DNA (mtDNA), a recently discovered pro-inflammatory agent, is released by cells upon insult. This study aimed to detect changes in plasma mtDNA levels at different time points after infantile CPB and explore its potential association with inflammatory mediators.

Plasma mtDNA levels increased at T2 and peaked at T3. Significant positive correlations were found between peak plasma mtDNA (at T3) and several inflammatory biomarkers, including IL-6 (at T3) (r=0.62, P<0.001), IL-8 (at T2) (r=0.53, P<0.001), and TNF-α (at T3) (r=0.61, P<0.001).