Clinical characteristics and outcomes of hospitalized patients with COVID-19 in a city of South Brazil: Have they changed through the first year of the pandemic?

The Coronavirus Disease 2019 (COVID-19) pandemic posed various challenges to the healthcare system and disease management. This study aimed to describe changes in the clinical characteristics and outcomes of hospitalized patients during the first year of the COVID-19 pandemic in a city in southern Brazil. This prospective study was carried out in two tertiary care private hospitals in Curitiba. A total of 1151 patients hospitalized between March 2020 and March 2021 were included. We identified three epidemiological critical periods of the pandemic and compared patients' characteristics and the frequencies of oral intubation, intensive care unit (ICU) admission and mortality. Continuous variables were analyzed by variance analysis model (ANOVA) or the Kruskal-Wallis nonparametric test and categorical variables by the chi-square or Fisher's exact test. Models for univariate and multivariate logistic regression analysis were adjusted to identify the factors associated with mortality. All p-values were two-tailed and p<0.05 was considered statistically significant. The average age of the patients was 58 years and 60.9% (n = 701) were males. The most prevalent comorbidities were systemic arterial hypertension, diabetes and obesity. There were no significant variations in the demographic characteristics and previous comorbidities of the patients for the different periods of analysis. Mortality was positively associated with the age ≥65 years and the presence of one or more cardiometabolic comorbidities (p<0.001). March 2021 was the most important critical period of the pandemic since there were higher frequencies of patients admitted later in the course of the disease, with desaturation and more symptoms at hospital admission (p<0.001). There was also an increase in the duration of hospital stay (p<0.001) and the frequencies of all critical outcomes for this period: oral intubation (p<0.001), ICU admission (p = 0.606) and mortality (p = 0.001). Our key findings revealed that, although there were no statistically significant differences between the subgroups of hospitalized patients over time in terms of demographic characteristics and comorbidities, the course of COVID-19 was significantly more severe for patients admitted to the hospital at the end of the first year of the pandemic in Brazil.

Lung Inflammasome Activation in SARS-CoV-2 Post-Mortem Biopsies.

The inflammasome complex is a key part of chronic diseases and acute infections, being responsible for cytokine release and cell death mechanism regulation. The SARS-CoV-2 infection is characterized by a dysregulated cytokine release. In this context, the inflammasome complex analysis within SARS-CoV-2 infection may prove beneficial to understand the disease's mechanisms. Post-mortem minimally invasive autopsies were performed in patients who died from COVID-19 (n = 24), and lung samples were compared to a patient control group (n = 11) and an Influenza A virus H1N1 subtype group from the 2009 pandemics (n = 10). Histological analysis was performed using hematoxylin-eosin staining. Immunohistochemical (IHC) staining was performed using monoclonal antibodies against targets: ACE2, TLR4, NF-κB, NLRP-3 (or NALP), IL-1ß, IL-18, ASC, CASP1, CASP9, GSDMD, NOX4, TNF-α. Data obtained from digital analysis underwent appropriate statistical tests. IHC analysis showed biomarkers that indicate inflammasome activation (ACE2; NF-κB; NOX4; ASC) were significantly increased in the COVID-19 group (p < 0.05 for all) and biomarkers that indicate cell pyroptosis and inflammasome derived cytokines such as IL-18 (p < 0.005) and CASP1 were greatly increased (p < 0.0001) even when compared to the H1N1 group. We propose that the SARS-CoV-2 pathogenesis is connected to the inflammasome complex activation. Further studies are still warranted to elucidate the pathophysiology of the disease.

The Pathogenesis of COVID-19 Myocardial Injury: An Immunohistochemical Study of Postmortem Biopsies.

Rationale: Myocardial injury associates significantly and independently with mortality in COVID-19 patients. However, the pathogenesis of myocardial injury in COVID-19 remains unclear, and cardiac involvement by SARS-CoV-2 presents a major challenge worldwide. Objective: This histological and immunohistochemical study sought to clarify the pathogenesis and propose a mechanism with pathways involved in COVID-19 myocardial injury. Methods and Results: Postmortem minimally invasive autopsies were performed in six patients who died from COVID-19, and the myocardium samples were compared to a control group (n=11). Histological analysis was performed using hematoxylin-eosin and toluidine blue staining. Immunohistochemical (IHC) staining was performed using monoclonal antibodies against targets: caspase-1, caspase-9, gasdermin-d, ICAM-1, IL-1ß, IL-4, IL-6, CD163, TNF-α, TGF-ß, MMP-9, type 1 and type 3 collagen. The samples were also assessed for apoptotic cells by TUNEL. Histological analysis showed severe pericardiocyte interstitial edema and higher mast cells counts per high-power field in all COVID-19 myocardium samples. The IHC analysis showed increased expression of caspase-1, ICAM-1, IL-1ß, IL-6, MMP-9, TNF-α, and other markers in the hearts of COVID-19 patients. Expression of caspase-9 did not differ from the controls, while gasdermin-d expression was less. The TUNEL assay was positive in all the COVID-19 samples supporting endothelial apoptosis. Conclusions: The pathogenesis of COVID-19 myocardial injury does not seem to relate to primary myocardiocyte involvement but to local inflammation with associated interstitial edema. We found heightened TGF-ß and interstitial collagen expression in COVID-affected hearts, a potential harbinger of chronic myocardial fibrosis. These results suggest a need for continued clinical surveillance of patients for myocardial dysfunction and arrythmias after recovery from the acute phase of COVID-19.

Covid-19 cytokine storm in pulmonary tissue: Anatomopathological and immunohistochemical findings.

The COVID-19 pandemic is a worldwide threat, and information on physiopathological aspects of the disease is limited. Despite efforts in searching treatment options, a better understanding of the SARS-CoV-2 pathways can contribute to managing severe cases. In this study, we aim to describe pathological and immunopathogenic findings of two different cases, both in the high-risk group. Post-mortem lung biopsies were analyzed by traditional and immunohistochemical methods. Tissue expression of innate and adaptive immune response biomarkers was tested. We observed a higher innate response in case 1 with an abundance of mast cells, scarce CD8+ lymphocytes, high expression of TNF-alpha, and almost absent adaptative immune response. In case 2, the adaptative immune response was present, with numerous CD8+ lymphocytes and higher levels of IL-4 and TGF-beta. Both cases converged to a prothrombotic state expressing high IL-6, followed by ICAM-1 expression and endotheliites leading to systemic inflammatory response syndrome. In conclusion, differences in age and comorbidities and immune response described here may be related to the SARS-CoV-2 delay in the adaptative immune response, evolution stage of diffuse alveolar damage, and progression for systemic inflammatory response syndrome.