Is NOX2 upregulation implicated in myocardial injury in patients with pneumonia?

Abstract

In the present study, we tested the hypothesis that oxidative stress could be implicated in myocardial damage during the acute phase of pneumonia. NOX2 activation, the catalytic subunit of NADPH oxidase, and high-sensitivity cardiac troponin T (hs-cTnT) elevation have been analyzed in two hundred forty-eight consecutive patients hospitalized for community-acquired pneumonia. Serum NOX2-derived peptide (sNOX2-dp), a marker of NOX2 activation, and 8-isoprostaglandin F2α (8-iso-PGF2α), a marker of oxidative stress, were measured upon admission; serum hs-cTnT and ECG were measured every 12 and 24 h, respectively. One hundred thirty-five patients (54%) showed elevated serum levels of hs-cTnT (>0.014 μg/L). A logistic regression analysis showed sNOX2-dp (p<0.001), Pneumonia Severity Index score (p<0.001), renal failure (p=0.024), and ejection fraction (p<0.001) as independent predictors of elevated serum levels of hs-cTnT. Serum sNOX2-dp was linearly correlated with hs-cTnT (Rs=0.538; p<0.001) and 8-iso-PGF2α (Rs=0.354; p<0.001). The study provides the first evidence of a significant association between serum cardiac Troponin T elevation and NOX2 upregulation in patients with pneumonia. This finding raises the hypothesis that NOX2-derived oxidative stress may be implicated in myocardial injury and that its inhibition could be a novel therapeutic strategy to limit it.

FIG. 1.

Serum sNOX2-dp (A) and isoprostanes (B) in (i) patients with hs-cTnT≤0.014 μg/L; (ii) patients with no-myocardial infarction (MI)-related troponin elevation (hs-cTnT>0.014 μg/L); and (iii) patients with signs of MI.