Nitrosative stress and cytokines are linked with the severity of sepsis and organ dysfunction

An imbalance in oxidant-antioxidant status may impact the severity of sepsis. We hypothesised links between nitrosative stress and pro-inflammatory cytokines and their correlation with the severity of sepsis and associated organ dysfunction.

The hypothesis was tested in 110 patients with sepsis (in whom a disease severity score (APACHE II) and assessment of organ failure score (SOFA) were determined) and 55 healthy volunteers. Neutrophil inducible nitric oxide synthase (iNOS) expressions at mRNA and protein levels were estimated by real-time PCR and immuno-precipitation followed by Western blotting, respectively. Nitric oxide (NO) content was assessed in neutrophils by confocal microscopy, plasma nitrite by the Griess reaction and inflammatory cytokines (TNF-α, IFN-γ and IL-8) by ELISA (in plasma) and real-time PCR (in neutrophils). Serum bilirubin and creatinine were determined by routine methods and lung function by the PaO₂/FiO₂ ratio.

Increased neutrophil iNOS expression and NO content, plasma total nitrite content and pro-inflammatory cytokines were present in sepsis patients (all P < 0.001). Plasma nitrite correlated with cytokines, APACHE II, SOFA, PaO₂/FiO₂ ratio, serum bilirubin and creatinine clearance (all r² 0.63-0.85, P < 0.001). Cytokines correlated with nitrite, APACHE II, SOFA, PaO₂/FiO₂ ratio, serum bilirubin and creatinine clearance (all r² 0.35-0.85, P < 0.001).

Neutrophils iNOS expression, NO content, plasma nitrite and cytokines have a role in the assessment of the severity of sepsis and organ toxicity.