Neutrophil-mediated oxidative stress and albumin structural damage predict COVID-19-associated mortality

This work reports that COVID-19-induced oxidative stress inflicts structural damages to human serum albumin (HSA) and is linked with mortality outcome in critically ill patients. Analyzing blood samples from patients and healthy individuals, the paper provides evidence that neutrophils are major sources of oxidative stress in blood and that hydrogen peroxide is highly accumulated in plasmas of non-survivors. The electron paramagnetic resonance spectra of spin-labeled fatty acids (SLFAs) bound with HSA in whole blood of control, survivor, and non-survivor subjects (n=10–11) were analyzed to probe structural damages to the protein. Non-survivors’ HSA showed dramatically altered biophysical parameters that reflect remarkably fluid protein microenvironments. Following loading/unloading of 16-DSA, the results show that the transport function of HSA may be impaired in severe patients. Stratified at the means, Kaplan–Meier survival analysis indicated that lower values of S/W ratio and accumulated H2O2 in plasma significantly predicted in-hospital mortality.