Superoxide dismutase alterations in COVID-19: implications for disease severity and mortality prediction in the context of omicron variant infection.

Background: In the few reports to date, the changes in superoxide dismutase (SOD), a key factor in cellular protection against superoxide, in COVID-19 have been very inconsistent and contradictory. There is also a lack of data on COVID-19 induced by Omicron variant. Further investigation is warranted to figure out SOD alterations in COVID-19, particularly within the context of ongoing Omicron variant infection, which may provide clues to its role within COVID-19 pathogenesis and open up new avenues for COVID-19 treatment. Methods: SOD activity in 109 COVID-19 patients (including 46 severe cases and 63 mild to moderate cases) and 30 matched healthy controls were quantified. Demographic data, blood cell counts, biochemical indicators, coagulation indicators, and inflammatory markers were also recorded. Results: SOD, an important key node, experienced a significant decrease in COVID-19, with the severe patients exhibiting lower activity compared to the mild to moderate patients and control healthy. Notably, severe patients who deceased had the lowest SOD activity. Correlation analysis revealed significant correlations between SOD and inflammatory markers, organ injury markers, coagulation dysfunction indicators, nutritional markers, and lymphocytes counts. The ROC curve also showed good performance for the differentiation of severe cases and the prediction of death. Conclusion: SOD activity was significantly decreased in COVID-19 infected with Omicron variant and significantly correlated with systemic changes, and could be used as a biomarker to assess disease severity and predict mortality in COVID-19 clinical pathway management. Additionally, this finding will contribute to exploring new potential direction for the treatment of severe COVID-19 patients.

Endothelial dysfunction and disease severity in COVID-19: Insights from circulating Tang cell counts as a potential biomarker.

BACKGROUND AND AIM: Endothelial dysfunction is a common risk factor of severe COVID-19. Angiogenic T cells (Tang cells) play a critical role in repairing endothelial injury; however, their changes and potential roles in COVID-19 remain unclear. We aimed to assess Tang cell counts in patients with COVID-19 and evaluate their association with disease severity and prognosis. METHODS: Circulating Tang cell populations in patients with COVID-19 and healthy controls were quantified using flow cytometry. Demographic and routine laboratory data were recorded. RESULTS: The Tang cell count decreased significantly with increasing disease severity and were lowest in fatal cases. Additionally, the Tang cell count was significantly decreased in patients with comorbid cardiovascular disease or hypertension. Tang cell counts were negatively correlated with inflammatory markers, kidney and myocardial injury markers, coagulation dysfunction indicators, and viral load and positively correlated with oxidative stress markers, nutritional markers, and lymphocytes. Receiver operating characteristic curves confirmed that Tang cell count could serve as a potential biomarker for predicting disease severity and patient mortality. CONCLUSIONS: Circulating Tang cell count is significantly reduced in patients with COVID-19 and is correlated with disease severity and prognosis. The Tang cell count is an important potential biomarker for COVID-19 clinical management. Additionally, these findings provide insight into the pathological features of COVID-19 endothelial injury and provide new directions for treatment.

Sandwich pair nanobodies, a potential tool for electrochemical immunosensing serum prostate-specific antigen with preferable specificity.

Prostate-Specific Antigen (PSA) is a crucial biomarker for screening prostate cancer, but a sensitive and selective immunosensor for rapid quantification of serum PSA remains to be developed. In this study, a sandwich pair of nanobodies (Nbs) (i.e., Nb2 and Nb40) against PSA surface antigen was obtained from an alpaca-derived immune phage display library. A sandwich-type immunosensor for the sensitive and selective detection of PSA in serum samples was ingeniously designed based on the pair of Nbs. The small size of Nb40 allowed high capture densities on the surface of reduced graphene oxide (rGO) nanocomposed with massive Au nanoparticles (rGO@AuNPs), which significantly improved the conductivity and provided a large area to anchor many primary antibodies. The secondary antibody Nb2 fused with streptavidin -binding peptide (SBP) cooperated with Nb40 for PSA sandwiching. Accompanying introduction of horseradish peroxidase-streptavidin (HRP-SA) coupled with Nb2-SBP, the faradaic current was linearly correlated with the logarithm of PSA concentration in a range of 0.1-100 ng mL-1. More importantly, this immunosensor exhibited excellent selectivity, stability, and reproducibility due to the sandwich pair Nbs. The proposed immunosensor was successfully applied in determining PSA in serum samples and could be used for the sensitive and specific detection of PSA.