Morphologic Findings in the Cerebral Cortex in COVID-19: Association of Microglial Changes with Clinical and Demographic Variables.

Despite the enormous interest in COVID-19, there is no clear understanding of the mechanisms underlying the neurological symptoms in COVID-19. Microglia have been hypothesized to be a potential mediator of the neurological manifestations associated with COVID-19. In most existing studies to date, morphological changes in internal organs, including the brain, are considered in isolation from clinical data and defined as a consequence of COVID-19. We performed histological immunohistochemical (IHC) studies of brain autopsy materials of 18 patients who had died from COVID-19. We evaluated the relationship of microglial changes with the clinical and demographic characteristics of the patients. The results revealed neuronal alterations and circulatory disturbances. We found an inverse correlation between the integral density Iba-1 (microglia/macrophage-specific marker) IHC staining and the duration of the disease (R = -0.81, p = 0.001), which may indicate a reduced activity of microglia and do not exclude their damage in the long-term course of COVID-19. The integral density of Iba-1 IHC staining was not associated with other clinical and demographic factors. We observed a significantly higher number of microglial cells in close contact with neurons in female patients, which confirms gender differences in the course of the disease, indicating the need to study the disease from the standpoint of personalized medicine.

Bacteriophage Cocktails in the Post-COVID Rehabilitation.

Increasing evidence suggests that gut dysbiosis is associated with coronavirus disease 2019 (COVID-19) infection and may persist long after disease resolution. The excessive use of antimicrobials in patients with COVID-19 can lead to additional destruction of the microbiota, as well as to the growth and spread of antimicrobial resistance. The problem of bacterial resistance to antibiotics encourages the search for alternative methods of limiting bacterial growth and restoring the normal balance of the microbiota in the human body. Bacteriophages are promising candidates as potential regulators of the microbiota. In the present study, two complex phage cocktails targeting multiple bacterial species were used in the rehabilitation of thirty patients after COVID-19, and the effectiveness of the bacteriophages against the clinical strain of Klebsiella pneumoniae was evaluated for the first time using real-time visualization on a 3D Cell Explorer microscope. Application of phage cocktails for two weeks showed safety and the absence of adverse effects. An almost threefold statistically significant decrease in the anaerobic imbalance ratio, together with an erythrocyte sedimentation rate (ESR), was detected. This work will serve as a starting point for a broader and more detailed study of the use of phages and their effects on the microbiome.

The Role of Von Willebrand Factor in the Pathogenesis of Pulmonary Vascular Thrombosis in COVID-19.

The increased plasma levels of von Willebrand factor (VWF) in patients with COVID-19 was reported in many studies, and its correlation with disease severity and mortality suggest its important role in the pathogenesis of thrombosis in COVID-19. We performed histological and immunohistochemical studies of the lungs of 29 patients who died from COVID-19. We found a significant increase in the intensity of immunohistochemical reaction for VWF in the pulmonary vascular endothelium when the disease duration was more than 10 days. In the patients who had thrombotic complications, the VWF immunostaining in the pulmonary vascular endothelium was significantly more intense than in nonsurvivors without thrombotic complications. Duration of disease and thrombotic complications were found to be independent predictors of increased VWF immunostaining in the endothelium of pulmonary vessels. We also revealed that bacterial pneumonia was associated with increased VWF staining intensity in pulmonary arterial, arteriolar, and venular endothelium, while lung ventilation was an independent predictor of increased VWF immunostaining in arterial endothelium. The results of the study demonstrated an important role of endothelial VWF in the pathogenesis of thrombus formation in COVID-19.

Six-Month Quality of Life in COVID-19 Intensive Care Unit Survivors.

OBJECTIVES: Because there is increasing evidence of serious deterioration in long-term quality of life (QoL) in coronavirus 2019 (COVID-19) intensive care unit (ICU) survivors, the authors identified predictors of poor quality of life in these patients. DESIGN: Prospective cohort study. SETTING: Research hospital repurposed into a COVID-19 center. PARTICIPANTS: Consecutive patients admitted in COVID-19 ICUs between March and June 2020. INTERVENTIONS: An SF-36 questionnaire, which included physical and mental items, was used six months after patient's discharge. MEASUREMENTS AND MAIN RESULTS: A total of 403 patients were managed in the ICU, with a hospital mortality of 181 of 403 (44.9%), and 16 (4.0%) patients died within six months. Among the 125 questionnaire responders, only 32.0% and 52% had a normal quality of life in terms of the physical and mental component of health. Multivariate analysis identified low-molecular-weight heparin treatment in the ICU as the only modifiable factor associated with an increase in physical component of QoL odds ratio (OR) 3.341 (95% confidence interval 1.298-8.599), p = 0.012, and age ≥52 years OR 0.223 and female sex OR 0.321 were significantly associated with a decrease in the physical component. Medical history of cerebrovascular insufficiency was significantly associated with a decrease in mental component of QoL OR 0.125, and the only factor associated with an increase in the mental health component was body mass index ≥27.6 kg/m2 OR 7.466. CONCLUSIONS: In COVID-19 ICU survivors the authors identified treatment with low- molecular-weight heparin as a predictor of improved physical component of QoL at 6 months.

Involvement of Oxidative Stress and the Innate Immune System in SARS-CoV-2 Infection.

The emergence of the novel coronavirus in December 2019 in China marked the beginning of a pandemic that impacted healthcare systems and economic life all over the world. The virus primarily targets the respiratory system causing severe acute respiratory syndrome (SARS) in some patients, and therefore received the name of SARS-CoV-2. The pathogen stands out among other coronaviruses by its rapid transmission from human to human, with the majority of infected individuals being asymptomatic or presenting with only minor illness, therefore facilitating the pathogen spread. At the same time, people from the risk groups, such as the elderly, patients suffering from chronic diseases, or obese individuals, have increased chances of developing a severe or even fatal disease. The search for risk factors explaining this phenomenon continues. In this review, we focus on the known mechanisms of SARS-CoV-2 infection affecting the functioning of the immune system and discuss potential risk factors responsible for the severe disease course. Oxidative stress is one of such factors, which plays a prominent role in innate immunity activity, and recent research has revealed its tight involvement in SARS-CoV-2 infection. We discuss these recent findings and the development of excessive inflammation and cytokine storm observed during SARS-CoV-2 infection. Finally, we consider potential use of antioxidant drugs for alleviating the severe symptoms in affected patients.