Targeting C5aR1 signaling reduced neutrophil extracellular traps and ameliorates COVID-19 pathology (preprint)

Patients with severe COVID-19 develop acute respiratory distress syndrome (ARDS) that may progress to cytokine storm syndrome, organ dysfunction, and death. Considering that complement component 5a (C5a), through its cellular receptor C5aR1, has potent proinflammatory actions, and plays immunopathological roles in inflammatory diseases, we investigated whether C5a/C5aR1 pathway could be involved in COVID-19 pathophysiology. C5a/C5aR1 signaling increased locally in the lung, especially in neutrophils of critically ill COVID-19 patients compared to patients with influenza infection, as well as in the lung tissue of K18-hACE2 Tg mice (Tg mice) infected with SARS-CoV-2. Genetic and pharmacological inhibition of C5aR1 signaling ameliorated lung immunopathology in Tg-infected mice. Mechanistically, we found that C5aR1 signaling drives neutrophil extracellular trap (NET)s-dependent immunopathology. These data confirm the immunopathological role of C5a/C5aR1 signaling in COVID-19 and indicate that antagonist of C5aR1 could be useful for COVID-19 treatment. Keywords: COVID-19, C5aR1, C5a, SARS-CoV-2, Myeloid cells, Neutrophils, NETs

Impact of COVID-19 pandemic on mental health, social connectedness and cognitive performance of older adults

The COVID-19 pandemic has profoundly impacted older adult's health and well-being worldwide. We explored the impact of the COVID-19 pandemic on daily activities and mental health and its relationship with cognitive performance in older adults. Methods One-hundred individuals 60 years and older, without cognitive impairment and enrolled in the Brazilian Memory Study (BRAMS), a longitudinal study, were applied the UCLA Loneliness Scale, Perceived Stress Scale (PSS), Geriatric Depression Scale (GDS), and Mini-Mental State Examination (MMSE). Participants were asked whether they had changes in daily routine and social connectedness during the pandemic. Results Almost half of the participants (48.4%) reported that the COVID-19 pandemic significantly affected their lives, 38.9% lost a relative or friend because of COVID-19, and 60% had daily routine changes. Relationships (40.5%) and emotion (22%) were reported as the most impacted area. Stopping physical activities and stay at home represented the main routine changed for 78% of participants. The use of voice messages through mobile phones to maintain social connectedness increased from 24.2% to 42.1%. For 38% of participants, their autonomy to daily decisions decreased, and 40% complained that memory got worse during the pandemic. More than 30% felt more stress, loneliness, or depression than in the pre-pandemic period. Controlling for age, sex, and education, higher loneliness scores were significantly associated with low MMES scores (p = 0.018). Conclusion Significant changes in life, daily routine, social connectedness, and mental health-related to the COVID-19 pandemic were reported by older adult participants. Loneliness was associated with lower cognitive performance.

The Mediating Role of Resilience and Life Satisfaction in the Relationship between Stress and Burnout in Medical Students during the COVID-19 Pandemic (preprint)

Following the WHO's declaration of a public health emergency due to the COVID-19 outbreak, the subsequent quarantine and confinement measures that were adopted, including distance learning measures, were shown to have caused a significant deterioration in the mental health of medical students. The goal of this study was to explore the mediating role of resilience and life satisfac-tion in the relationship between perceived stress and burnout among medical students in the con-text of COVID-19. A transversal assessment was performed using an online questionnaire, to which 462 students responded. The instruments applied were the Perceived Stress Scale-10, the Resilience Scale-25 items, the Satisfaction with Life Scale (SWLS) and the Burnout Scale (Olden-burg Inventory). A regression model was estimated for each dimension of burnout. The results revealed that resilience and life satisfaction play a mediating role in the association between stress and the dimensions of burnout. This suggests that measures of promoting mental health based on resilience and improving perceptions of life should be implemented.

Gamma-oryzanol as a potential modulator of oxidative stress and inflammation via PPAR-y in adipose tissue: a hypothetical therapeutic for cytokine storm in COVID-19?

The literature has reported a higher prevalence of negative clinical outcomes due to Coronavirus disease 19 (COVID-19) in obese individuals. This can be explained by the cytokine storm, result from the cytokine production from both obesity and viral infection. Gamma-oryzanol (γOz) is a compound with anti-inflammatory and antioxidant activities. However, little is known about the γOz action as a possible agonist of peroxisome proliferator-activated receptor gamma (PPAR-γ). The aim of this study was to test the hypothesis that γOz attenuates the cytokine storm by stimulating PPAR-γ in the adipose tissue. METHODS: Male Wistar rats were randomly divided into three experimental groups and fed ad libitum for 30 weeks with control diet (C, n = 6), high sugar-fat diet (HSF, n = 6) or high sugar-fat diet + Î³Oz (HSF + Î³Oz, n = 6). HSF groups also received water + sucrose (25%). The γOz dose was 0.5% in the chow. Evaluation in animals included caloric intake, body weight, adiposity index, plasma triglycerides, and HOMA-IR. In adipose tissue was evaluated: PPAR-γ gene and protein expression, inflammatory and oxidative stress parameters, and histological analysis. RESULTS: Adipose tissue dysfunction was observed in HSF group, which presented remarkable PPAR-γ underexpression and increased levels of cytokines, other inflammatory markers and oxidative stress. The γOz treatment prevented adipose tissue dysfunction and promoted PPAR-γ overexpression. CONCLUSION: Natural compounds as γOz can be considered a coadjutant therapy to prevent the cytokine storm in COVID-19 patients with obesity conditions.

Exploring lectin-glycan interactions to combat COVID-19: Lessons acquired from other enveloped viruses.

The emergence of a new human coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has imposed great pressure on the health system worldwide. The presence of glycoproteins on the viral envelope opens a wide range of possibilities for the application of lectins to address some urgent problems involved in this pandemic. In this work, we discuss the potential contributions of lectins from nonmammalian sources in the development of several fields associated with viral infections, most notably COVID-19. We review the literature on the use of nonmammalian lectins as a therapeutic approach against members of the Coronaviridae family, including recent advances in strategies of protein engineering to improve their efficacy. The applications of lectins as adjuvants for antiviral vaccines are also discussed. Finally, we present some emerging strategies employing lectins for the development of biosensors, microarrays, immunoassays and tools for purification of viruses from whole blood. Altogether, the data compiled in this review highlight the importance of structural studies aiming to improve our knowledge about the basis of glycan recognition by lectins and its repercussions in several fields, providing potential solutions for complex aspects that are emerging from different health challenges.

Prevalence and risk factors for agents causing diarrhea (Coronavirus, Rotavirus, Cryptosporidium spp., Eimeria spp., and nematodes helminthes) according to age in dairy calves from Brazil.

The present study attempted to verify the prevalence of and risk factors for diarrhea-causing agents in dairy calves from Brazil. Additionally, ages with a higher risk of occurrence for each agent were verified by means of the receiver operating characteristic (ROC) curve. The collections were performed on 39 farms, belonging to 29 municipalities located in eight states of Brazil. It was possible to conclude that the prevalence of Coronavirus, Rotavirus, Cryptosporidium spp., Eimeria spp., and nematodes was 7.20% (95% CI 4.54-9.78), 6.37% (95% CI 3.85-8.89), 51.52% (95% CI 45.26-55.57), 3.46% (95% CI 2.24-4.67), and 3.46% (95% CI 2.24-4.67), respectively. Ages with higher probabilities of occurrence of these diseases in calves were < 10, > 8, > 6, > 37, and > 36 days, respectively. Diarrhea occurred more significantly (P < 0.0001) in animals less than 21 days old and mainly on those receiving milk through automatic feeders (P < 0.001). Cryptosporidium spp. were a risk factor for the occurrence of Rotavirus, and vice versa (P = 0.0039) and presented a positive correlation with Coronavirus (P = 0.0089). Calves that drink water from rivers, streams, and ponds had a higher chance of being infected by Eimeria spp. (P < 0.0001), as well as developing infection by nematodes (P < 0.0001). The results found in this study highlight the importance of studying the agents of diarrhea together, once they act as coinfection where the losses triggered for the owners will involve some of these agents simultaneously.