Novel phenotypes of coronavirus disease: a temperature-based trajectory model

Fever temperatures modulate intraprotein dynamics and enhance the binding affinity between monoclonal antibodies and the Spike protein from SARS-CoV-2

Fever is a typical symptom of most infectious diseases. While prolonged fever may be clinically undesirable, mild reversible fever (<39℃, 312 K) can potentiate the immune responses against pathogens. Here, using molecular dynamics and free energy calculations, we investigated the effect of febrile temperatures (38℃ to 40℃, 311 K to 313 K) on the immune complexes formed by the SARS-CoV-2 spike protein with two neutralizing monoclonal antibodies. In analyzing the conformational dynamics of the interactions between the antibodies and the spike protein under different thermal conditions, we found that, at mild fever temperatures (311–312 K), the binding affinities of the two antibodies improve when compared to the physiological body temperature (37℃, 310 K). Furthermore, only at 312 K, antibodies exert distinct mechanical effects on the receptor binding domains of the spike protein that may hinder SARS-CoV-2 infectivity. Enhanced antibody binding affinity may thus be obtained using appropriate temperature conditions.

Impact of partial pressure of oxygen trajectories on the incidence of acute kidney injury in patients undergoing cardiopulmonary bypass

BACKGROUND

To investigate the impact of the dynamic oxygenation status on the incidence of acute kidney injury (AKI) in patients undergoing cardiopulmonary bypass.

METHODS

This retrospective study was performed using data extracted from the Medical Information Mart for Intensive Care III database. A group-based trajectory approach was used to identify partial pressure of oxygen (PaO₂) trajectories using dynamic change in PaO₂ within 48 hours after intensive care unit admission.

RESULTS

In total, 5,824 patients were included. Four PaO₂ trajectories were identified: Trajectory 1 (Traj-1), hyperoxia and rapid decrease; Trajectory 2 (Traj-2), hyperoxia and rapid decrease similar to that of Traj-1; Trajectory 3 (Traj-3), normoxemia and rapid increase in PaO₂; and Trajectory 4 (Traj-4), hyperoxia and gradual decrease. Compared with the Traj-1 group, the Traj-3 group had a significantly lower initial Sequential Organ Failure Assessment score, similar vasopressor use rate, and a higher fraction of inspired oxygen. However, the risk of developing AKI was significantly higher in the Traj-3 [adjusted odds ratio (OR): 1.7, 95% confidence interval (CI): 1.1-2.7] and Traj-4 groups (OR: 1.9, 95% CI: 1.4-2.5) than in the Traj-1 group.

CONCLUSIONS

Patients with persistent hyperoxia had a higher incidence of AKI than those with transient hyperoxia. Further studies are required to determine potential underlying mechanisms.