Histopathology features of the lung in COVID-19 patients

The Histopathologic Features of Early COVID Pneumonia in a Pediatric Patient: New Insight into the Role of Macrophages

A life-threatening complication of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is acute respiratory distress syndrome. Our understanding of the pathologic changes in coronavirus disease 2019 (COVID-19) is based almost exclusively on post-mortem analyses of adults. These studies established several hallmarks of SARS-CoV-2 lung infection, including diffuse alveolar damage, microvascular thrombi, and acute bronchopneumonia. We describe a fatal example of COVID pneumonia in a 9-year-old girl who presented with fever 10 months following the diagnosis of ALK-positive anaplastic large cell lymphoma (ALCL). A chest computed tomography scan revealed left upper lobe lung consolidation and nodular airspace disease, and an initial SARS-CoV-2 nasopharyngeal swab (RT-PCR) was negative. A subsequent lung biopsy performed due to concern for relapsed ALCL demonstrated sheets of intra-alveolar and interstitial macrophages, and macrophage-rich fibrinous exudates. Immunohistochemical and in-situ hybridization stains confirmed these macrophages as the predominant SARS-CoV-2-infected cell type. Subsequent RT-PCR testing of upper and lower respiratory tract samples was positive for SARS-CoV-2 infection. Whole genome sequencing confirmed the presence of the B.1.617.2 (Delta) variant. This biopsy illustrates the histopathologic features of early COVID pneumonia in antemortem lung tissue from a pediatric patient, and establishes macrophages as a potential source of SARS-CoV-2 amplification.

Mexican Hispanics show significant improvement in lung function approximately 1 year after having severe COVID-19

The long-term effects of COVID-19 on lung function are not understood, especially for periods extending beyond 1 year after infection. This observational, longitudinal study investigated lung function in Mexican Hispanics who experienced severe COVID-19, focusing on how the length of recovery affects lung function improvements. At a specialized COVID-19 follow-up clinic in Yucatan, Mexico, lung function and symptoms were assessed in patients who had recovered from severe COVID-19. We used z-scores, and Wilcoxon's signed rank test to analyse changes in lung function over time. Lung function was measured twice in 82 patients: the first and second measurements were taken a median of 94 and 362 days after COVID-19 diagnosis, respectively. Initially, 61% of patients exhibited at least one of several pulmonary function abnormalities (lower limit of normal = -1.645), which decreased to 22% of patients by 390 days post-recovery. Considering day-to-day variability in lung function, 68% of patients showed improvement by the final visit, while 30% had unchanged lung function from the initial assessment. Computed tomography (CT) scans revealed ground-glass opacities in 33% of patients. One year after infection, diffusing capacity of the lungs for carbon monoxide z-scores accounted for 30% of the variation in CT fibrosis scores. There was no significant correlation between the length of recovery and improvement in lung function based on z-scores. In conclusion, 22% of patients who recovered from severe COVID-19 continued to show at least one lung function abnormality 1 year after recovery, indicating a prolonged impact of COVID-19 on lung health.

A Histological Analysis and Detection of Complement Regulatory Protein CD55 in SARS-CoV-2 Infected Lungs

BACKGROUND

A complement imbalance in lung alveolar tissue can play a deteriorating role in COVID-19, leading to acute respiratory distress syndrome (ARDS). CD55 is a transmembrane glycoprotein that inhibits the activation of the complement system at the intermediate cascade level, blocking the activity of the C3 convertase.

OBJECTIVE

In our study, lung specimens from COVID-19 and ARDS-positive COVID+/ARDS+ patients were compared with COVID-19 and ARDS-negative COVID-/ARDS- as well as COVID-/ARDS+ patients.

METHODS

Histochemical staining and immunolabeling of CD55 protein were performed.

RESULTS

The COVID-/ARDS- specimen showed higher expression and homogeneous distribution of glycosaminoglycans as well as compactly arranged elastic and collagen fibers of the alveolar walls in comparison to ARDS-affected lungs. In addition, COVID-/ARDS- lung tissues revealed stronger and homogenously distributed CD55 expression on the alveolar walls in comparison to the disrupted COVID-/ARDS+ lung tissues.

CONCLUSIONS

Even though the collapse of the alveolar linings and the accumulation of cellular components in the alveolar spaces were characteristic of COVID+/ARDS+ lung tissues, evaluating CD55 expression could be relevant to understand its relation to the disease. Furthermore, targeting CD55 upregulation as a potential therapy could be an option for post-infectious complications of COVID-19 and other inflammatory lung diseases in the future.

Immunohistochemical and Morphometric Analysis of Lung Tissue in Fatal COVID-19

The primary targets of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the lungs are type I pneumocytes, macrophages, and endothelial cells. We aimed to identify lung cells targeted by SARS-CoV-2 using viral nucleocapsid protein staining and morphometric features on patients with fatal COVID-19. We conducted a retrospective analysis of fifty-one autopsy cases of individuals who tested positive for SARS-CoV-2. Demographic and clinical information were collected from forensic reports, and lung tissue was examined for microscopic lesions and the presence of specific cell types. Half of the evaluated cohort were older than 71 years, and the majority were male (74.5%). In total, 24 patients presented diffuse alveolar damage (DAD), and 50.9% had comorbidities (56.9% obesity, 33.3% hypertension, 15.7% diabetes mellitus). Immunohistochemical analysis showed a similar pattern of infected macrophages, infected type I pneumocytes, and endothelial cells, regardless of the presence of DAD (p > 0.5). The immunohistochemical reactivity score (IRS) was predominantly moderate but without significant differences between patients with and without DAD (p = 0.633 IRS for type I pneumocytes, p = 0.773 IRS for macrophage, and p = 0.737 for IRS endothelium). The nucleus/cytoplasm ratio shows lower values in patients with DAD (median: 0.29 vs. 0.35), but the difference only reaches a tendency for statistical significance (p = 0.083). Our study confirms the presence of infected macrophages, type I pneumocytes, and endothelial cells with a similar pattern in patients with and without diffuse alveolar damage.

Prior Influenza Infection Mitigates SARS-CoV-2 Disease in Syrian Hamsters

Seasonal infection rates of individual viruses are influenced by synergistic or inhibitory interactions between coincident viruses. Endemic patterns of SARS-CoV-2 and influenza infection overlap seasonally in the Northern hemisphere and may be similarly influenced. We explored the immunopathologic basis of SARS-CoV-2 and influenza A (H1N1pdm09) interactions in Syrian hamsters. H1N1 given 48 h prior to SARS-CoV-2 profoundly mitigated weight loss and lung pathology compared to SARS-CoV-2 infection alone. This was accompanied by the normalization of granulocyte dynamics and accelerated antigen-presenting populations in bronchoalveolar lavage and blood. Using nasal transcriptomics, we identified a rapid upregulation of innate and antiviral pathways induced by H1N1 by the time of SARS-CoV-2 inoculation in 48 h dual-infected animals. The animals that were infected with both viruses also showed a notable and temporary downregulation of mitochondrial and viral replication pathways. Quantitative RT-PCR confirmed a decrease in the SARS-CoV-2 viral load and lower cytokine levels in the lungs of animals infected with both viruses throughout the course of the disease. Our data confirm that H1N1 infection induces rapid and transient gene expression that is associated with the mitigation of SARS-CoV-2 pulmonary disease. These protective responses are likely to begin in the upper respiratory tract shortly after infection. On a population level, interaction between these two viruses may influence their relative seasonal infection rates.

Computational analysis of the interactions between Ebselen and derivatives with the active site of the main protease from SARS-CoV-2

The main protease (Mpro) of the novel coronavirus SARS-CoV-2 is a key target for developing antiviral drugs. Ebselen (EbSe) is a selenium-containing compound that has been shown to inhibit Mpro in vitro by forming a covalent bond with the cysteine (Cys) residue in the active site of the enzyme. However, EbSe can also bind to other proteins, like albumin, and low molecular weight compounds that have free thiol groups, such as Cys and glutathione (GSH), which may affect its availability and activity. In this study, we analyzed the Mpro interaction with EbSe, its analogues, and its metabolites with Cys, GSH, and albumin by molecular docking. We also simulated the electronic structure of the generated molecules by density functional theory (DFT) and explored the stability of EbSe and one of its best derivatives, EbSe-2,5-MeClPh, in the catalytic pocket of Mpro through covalent docking and molecular dynamics. Our results show that EbSe and its analogues bound to GSH/albumin have larger distance between the selenium atom of the ligands and the sulfur atom of Cys145 of Mpro than the other compounds. This suggests that EbSe and its GSH/albumin-analogues may have less affinity for the active site of Mpro. EbSe-2,5-MeClPh was found one of the best molecules, and in molecular dynamics simulations, it showed to undergo more conformational changes in the active site of Mpro, in relation to EbSe, which remained stable in the catalytic pocket. Moreover, this study also reveals that all compounds have the potential to interact closely with the active site of Mpro, providing us with a concept of which derivatives may be promising for in vitro analysis in the future. We propose that these compounds are potential covalent inhibitors of Mpro and that organoselenium compounds are molecules that should be studied for their antiviral properties.

Single cell spatial analysis reveals inflammatory foci of immature neutrophil and CD8 T cells in COVID-19 lungs

Single cell spatial interrogation of the immune-structural interactions in COVID -19 lungs is challenging, mainly because of the marked cellular infiltrate and architecturally distorted microstructure. To address this, we develop a suite of mathematical tools to search for statistically significant co-locations amongst immune and structural cells identified using 37-plex imaging mass cytometry. This unbiased method reveals a cellular map interleaved with an inflammatory network of immature neutrophils, cytotoxic CD8 T cells, megakaryocytes and monocytes co-located with regenerating alveolar progenitors and endothelium. Of note, a highly active cluster of immature neutrophils and CD8 T cells, is found spatially linked with alveolar progenitor cells, and temporally with the diffuse alveolar damage stage. These findings offer further insights into how immune cells interact in the lungs of severe COVID-19 disease. We provide our pipeline [Spatial Omics Oxford Pipeline (SpOOx)] and visual-analytical tool, Multi-Dimensional Viewer (MDV) software, as a resource for spatial analysis.

New and personalized ventilatory strategies in patients with COVID-19

Coronavirus disease (COVID-19) is caused by the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) virus and may lead to severe respiratory failure and the need for mechanical ventilation (MV). At hospital admission, patients can present with severe hypoxemia and dyspnea requiring increasingly aggressive MV strategies according to the clinical severity: noninvasive respiratory support (NRS), MV, and the use of rescue strategies such as extracorporeal membrane oxygenation (ECMO). Among NRS strategies, new tools have been adopted for critically ill patients, with advantages and disadvantages that need to be further elucidated. Advances in the field of lung imaging have allowed better understanding of the disease, not only the pathophysiology of COVID-19 but also the consequences of ventilatory strategies. In cases of refractory hypoxemia, the use of ECMO has been advocated and knowledge on handling and how to personalize strategies have increased during the pandemic. The aims of the present review are to: (1) discuss the evidence on different devices and strategies under NRS; (2) discuss new and personalized management under MV based on the pathophysiology of COVID-19; and (3) contextualize the use of rescue strategies such as ECMO in critically ill patients with COVID-19.

Virulence Profiles of Wild-Type, P.1 and Delta SARS-CoV-2 Variants in K18-hACE2 Transgenic Mice

Since December 2019, the world has been experiencing the COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and we now face the emergence of several variants. We aimed to assess the differences between the wild-type (Wt) (Wuhan) strain and the P.1 (Gamma) and Delta variants using infected K18-hACE2 mice. The clinical manifestations, behavior, virus load, pulmonary capacity, and histopathological alterations were analyzed. The P.1-infected mice showed weight loss and more severe clinical manifestations of COVID-19 than the Wt and Delta-infected mice. The respiratory capacity was reduced in the P.1-infected mice compared to the other groups. Pulmonary histological findings demonstrated that a more aggressive disease was generated by the P.1 and Delta variants compared to the Wt strain of the virus. The quantification of the SARS-CoV-2 viral copies varied greatly among the infected mice although it was higher in P.1-infected mice on the day of death. Our data revealed that K18-hACE2 mice infected with the P.1 variant develop a more severe infectious disease than those infected with the other variants, despite the significant heterogeneity among the mice.

Histopathological autopsy findings in lungs of pregnant and postpartum women who died of COVID-19 infections

Background

The coronavirus disease 2019 outbreak (COVID-19) caused by the SARS-CoV coronavirus, has been declared as a pandemic by the World Health Organization on 11 March 2020, as a result of which about 315,000,000 people all over the world have been infected and more than 5,000,000 died.

Objective

Many scientific articles have been published concerning histopathological changes in different organs, but data concerning the lung changes of pregnant and postpartum period women who died of COVID-19 infections are still scarce. The aim of our study was to review and summarize autopsy findings and histopathological changes in lungs of pregnant and postpartum period women who died of COVID-19 infections in Armenia during 2020-2021.

Material and methods

Lung tissue specimens of 14 pregnant and postpartum period women who died of COVID-19 infections and its complications were examined. Hematoxylin-eosin and van Gieson staining methods as well as immunohistochemical examinations were used.

Results

The average age of the dead women was 33.9 years. From 14 cases in 9 there were comorbidities. All cases of death were in the 2nd and 3rd trimester of pregnancy or early and late postpartum period. Forensic medical diagnosis included COVID-19 infection with bilateral polysegmented pneumonia and acute respiratory failure. Histopathological examination revealed diffuse alveolar damage of lungs (DAD) in predominantly proliferation/organizing stage.

Conclusion

Histopathological examination of lungs showed proliferative stage of DAD with signs of fibrosing pneumonia. Early diagnosis and hospitalization of pregnant women may prevent late complications of COVID-19 infection and fibrosing pneumonia development, as well as future risks of fatal outcomes in pregnant and early postpartum period.

Morphological and functional findings in COVID-19 lung disease as compared to Pneumonia, ARDS, and High-Altitude Pulmonary Edema

Coronavirus disease-2019 (COVID-19) may severely affect respiratory function and evolve to life-threatening hypoxia. The clinical experience led to the implementation of standardized protocols assuming similarity to severe acute respiratory syndrome (SARS-CoV-2). Understanding the histopathological and functional patterns is essential to better understand the pathophysiology of COVID-19 and then develop new therapeutic strategies. Epithelial and endothelial cell damage can result from the virus attack, thus leading to immune-mediated response. Pulmonary histopathological findings show the presence of Mallory bodies, alveolar coating cells with nuclear atypia, reactive pneumocytes, reparative fibrosis, intra-alveolar hemorrhage, moderate inflammatory infiltrates, micro-abscesses, microthrombus, hyaline membrane fragments, and emphysema-like lung areas. COVID-19 patients may present different respiratory stages from silent to critical hypoxemia, are associated with the degree of pulmonary parenchymal involvement, thus yielding alteration of ventilation and perfusion relationships. This review aims to: discuss the morphological (histopathological and radiological) and functional findings of COVID-19 compared to acute interstitial pneumonia, acute respiratory distress syndrome (ARDS), and high-altitude pulmonary edema (HAPE), four entities that share common clinical traits, but have peculiar pathophysiological features with potential implications to their clinical management.

SARS-CoV-2 infection downregulates myocardial ACE2 and potentiates cardiac inflammation in humans and hamsters

Myocardial pathologies resulting from SARS-CoV-2 infections are consistently rising with mounting case rates and reinfections; however, the precise global burden is largely unknown and will have an unprecedented impact. Understanding the mechanisms of COVID-19-mediated cardiac injury is essential toward the development of cardioprotective agents that are urgently needed. Assessing novel therapeutic strategies to tackle COVID-19 necessitates an animal model that recapitulates human disease. Here, we sought to compare SARS-CoV-2-infected animals with patients with COVID-19 to identify common mechanisms of cardiac injury. Two-month-old hamsters were infected with either the ancestral (D614) or Delta variant (B.1.617.2) of SARS-CoV-2 for 2 days, 7 days, and/or 14 days. We measured viral RNA and cytokine expression at the earlier time points to capture the initial stages of infection in the lung and heart. We assessed myocardial angiotensin-converting enzyme 2 (ACE2), the entry receptor for the SARS-CoV-2 virus, and cardioprotective enzyme, as well as markers for inflammatory cell infiltration in the hamster hearts at days 7 and 14. In parallel, human hearts were stained for ACE2, viral nucleocapsid, and inflammatory cells. Indeed, we identify myocardial ACE2 downregulation and myeloid cell burden as common events in both hamsters and humans infected with SARS-CoV-2, and we propose targeting downstream ACE2 downregulation as a therapeutic avenue that warrants clinical investigation.NEW & NOTEWORTHY Cardiac manifestations of COVID-19 in humans are mirrored in the SARS-CoV-2 hamster model, recapitulating myocardial damage, ACE2 downregulation, and a consistent pattern of immune cell infiltration independent of viral dose and variant. Therefore, the hamster model is a valid approach to study therapeutic strategies for COVID-19-related heart disease.

COVID-19 and fibrosis: Mechanisms, clinical relevance, and future perspectives

Coronavirus 2019 (COVID-19), caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) has had significant impacts worldwide since its emergence in December, 2019. Despite a high recovery rate, there is a growing concern over its residual, long-term effects. However, because of a lack of long-term data, we are still far from establishing a consensus on post-COVID-19 complications. The deposition of excessive extracellular matrix (ECM), known as fibrosis, has been observed in numerous survivors of COVID-19. Given the exceptionally high number of individuals affected, there is an urgent need to address the emergence of fibrosis post-COVID-19. In this review, we discuss the clinical relevance of COVID-19-associated fibrosis, the current status of antifibrotic agents, novel antifibrotic targets, and challenges to its management.

Persistent SARS-CoV-2 antigen presence in multiple organs of a naturally infected cat from Brazil

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of the disease coronavirus 2019 (COVID-19) in humans. SARS-CoV-2 has been identified in cats with or without clinical signs.

Case presentation

We describe the pathological and molecular findings in a six-month-old asymptomatic cat with SARS-CoV-2 infection from Brazil, belonging to a human family with COVID-19 cases. The pool of nasopharynx and oropharynx swabs at day zero tested positive by RT-qPCR for SARS-CoV-2. No amplification resulted from molecular testing performed on days 7 and 14. The cat was hit by a car and died 43 days after the molecular diagnosis. Immunohistochemistry at post-mortem examination demonstrated nucleocapsid protein in samples from the lungs, kidneys, nasal conchae, trachea, intestine, brain and spleen.

Conclusion

The present study has highlighted the possibility that viral antigens can be detected by immunohistochemistry in multiple organs six weeks after infection, although the same tissues tested negative by RT-PCR.

Blocking Toll-like receptor 9 attenuates bleomycin-induced pulmonary injury

Background

Acute respiratory distress syndrome (ARDS) is one of the most common complications in coronavirus disease 2019 patients suffering from acute lung injury (ALI). In ARDS, marked distortion of pulmonary architecture has been reported. The pulmonary lesions in ARDS include hemodynamic derangements (such as alveolar edema and hemorrhage), vascular and bronchiolar damage, interstitial inflammatory cellular aggregations, and eventually fibrosis. Bleomycin induces ARDS-representative pulmonary damage in mice and rats; therefore, we used bleomycin model mice in our study. Recently, Toll-like receptor 9 (TLR9) was implicated in the development of ARDS and ALI.

Methods

In this study, we evaluated the efficiency of a TLR9 blocker (ODN2088) on bleomycin-induced pulmonary damage. We measured the apoptosis rate, inflammatory reaction, and fibroplasia in bleomycin- and bleomycin + ODN2088-treated mice.

Results

Our results showed a significant amelioration in bleomycin-induced damage to pulmonary architecture following ODN2088 treatment. A marked decrease in pulmonary epithelial and endothelial apoptosis rate as measured by cleaved caspase-3 expression, inflammatory reaction as indicated by tumor necrosis factor α expression, and pulmonary fibrosis as demonstrated by Van Gieson staining and α-smooth muscle actin immunohistochemistry were observed following ODN2088 treatment.

Conclusions

All these findings indicate that blocking downstream TLR9 signaling could be beneficial in prevention or mitigation of ARDS through hemodynamic derangements, inflammation, apoptosis, and fibrosis.

Severe COVID-19 Pneumonia of Single Transplant Lung Sparing Native Fibrotic Lung

Supplemental Digital Content is available in the text.

Temporal Patterns of COVID-19-Associated Pulmonary Pathology: An Autopsy Study

Introduction

The novel coronavirus variant - severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) and the disease it causes clinically (novel coronavirus disease 2019 or COVID-19) have placed medical science into a frenzy due to the significant morbidity and mortality, as well as the myriad of clinical complications developing as a direct result of infection. The most notable and one of the most severe changes in COVID-19 develops in the lungs.

Materials and methods

All cases of real-time polymerase chain reaction (rtPCR)-proved COVID-19 subjected to autopsy were withdrawn from the central histopathology archive of a single tertiary medical institution - St. Marina University Hospital - Varna, Varna, Bulgaria. Pulmonary gross and histopathology changes observed on light microscopy with hematoxylin and eosin as well with other histochemical and immunohistochemical stains were compared with the time from patient-reported symptom onset to expiration, to compare the extent and type of changes based on disease duration.

Results

A total of 27 autopsy cases fit the established criteria. All cases clinically manifested with severe COVID-19. From the selected 27 cases, n=14 were male and n=13 were female. The mean age in the cohort was 67.44 years (range 18-91 years), with the mean age for males being 68.29 (range 38-80 years) and the mean age for females being 66.54 (range 18-91 years). Gross changes in patients who expired in the first 10 days after disease onset showed a significantly increased mean weight - 1050g, compared to a relatively lower weight in patients expiring more than 10 days after symptom onset - 940g. Histopathology changes were identified as intermittent (developing independent from symptom onset and persisting) - diffuse alveolar damage with hyaline membranes - acute respiratory distress syndrome, endothelitis with vascular degeneration and fibrin thrombi; early (developing within the first week, but persisting) - type II pneumocyte hyperplasia, alveolar cell multinucleation and scant interstitial mononuclear inflammation; intermediate (developing within the late first and second weeks) - Clara cell hyperplasia and late (developing after the second week of symptom onset) - respiratory tract and alveolar squamous cell metaplasia and fibrosis.

Conclusion

COVID-19-associated pulmonary pathology, both gross and histopathology, show a time-related dynamic with persistent early and a myriad of later developing dynamic changes in patients with severe disease. These changes underline both the severity of the condition, as well as the mechanisms and the probability of long-lasting severe complications in patients with post-COVID syndrome.

Severe acute respiratory syndrome-coronavirus 2 in domesticated animals and its potential of transmission: A meta-analysis

BACKGROUND AND AIM

The coronavirus diseases-2019 (COVID-19) pandemic has caused a global lockdown, which has limited the mobility of the public, and thus, more time is spent with their pets. Unfortunately, many social media have blamed pet animals as a reservoir of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), the etiologic agent of COVID-19, triggering a panic abandonment of pets. However, no article has summarized the information regarding the role of pets as SARS-CoV-2 reservoirs. This study aimed to evaluate the role of pets as a reservoir of SARS-CoV-2 on the basis of research papers (i.e., animal model, surveillance, and case report) published in 2020.

MATERIALS AND METHODS

The review was conducted using articles from the PubMed database in 2020, using the keywords "COVID-19 in domesticated animals," which were screened and analyzed. Only the data from research articles were mimicked and transformed to conduct a meta-analysis. The meta-analysis was conducted regarding the effects of inhabitation and viral shedding in pets. In this study, we used 95% confidence intervals.

RESULTS

A total of 132 papers in PubMed were related to the keywords, whereas only 12 papers were appropriate to answer the dynamics of the role of pets as the reservoir for SARS-CoV-2. Seven studies indicated the potential of cat-cat (4/7), human-cat (2/7), and human-dog (1/7) SARS-CoV-2 transmission. No study proved the presence of cat-human transmission. Another study showed that comingling did not affect SARS-CoV-2 viral shedding among a cat and dog. Furthermore, the viral shedding of cats and dogs caused asymptomatic manifestations and generated neutralizing antibodies within a short period of time.

CONCLUSION

SARS-CoV-2 transmission is present in domesticated animals, especially in pet cats and dogs, and transmission occurs between animals of the same species (cat-cat). The reverse zoonosis (zooanthroponosis) was found from human to cat/dog (comingled) with asymptomatic clinical signs due to the representation of neutralizing antibodies.

Clinical manifestations and socio-demographic status of COVID-19 patients during the second-wave of pandemic: A Bangladeshi experience

BACKGROUND

Bangladesh is a densely populated country with a substandard healthcare system and a mediocre economic framework. Due to the enormous number of people who have been unaware until now, the development of COVID-19's second-wave infection has become a severe threat. The present investigation aimed to characterize the clinical and socio-demographic characteristics of COVID-19 in Bangladesh.

METHODS

A cross-sectional analysis was carried out from all the other COVID-19 patients and confirmed by RT-PCR undergoing a specialized COVID-19 hospital. From March 1 to April 15, 2021, a total of 1326 samples were collected. Samples were only obtained from non-critical COVID-19 patients as critically ill patients required emergency intensive care medications. Then, from April 17 to May 03, 2021, SARS-CoV-2 infection and clinical assessment was performed based on interim guidelines from the WHO. The diagnosis was conducted through RT-PCR. Later, identifying the symptomatic and asymptomatic patient based on checking the Clinical Observation Form (COF). The patients filled the COF form. Finally, statistical analyses were done using the SPSS 20 statistical program.

RESULTS

In this investigation, a total of 326 patients were diagnosed as COVID-19 positive. Among them, approximately 19.02% (n = 62) were asymptomatic, and 80.98% (n = 264) were symptomatic. Here, the finding shows that the occurrence of this infection was varied depending on age, sex, residence, occupation, smoking habit, comorbidities, etc. However, Males (60.12%) were more affected than females (39.88%), and, surprisingly, this pandemic infected both urban and rural residents almost equally (urban = 50.92%; rural = 49.08%). Approximately 19% of the asymptomatic and 62% of symptomatic cases had at least one comorbid disorder. Interestingly, an unexpected result was exhibited in the case of smokers, where non-smokers were more affected than smokers. The study indicates community transmission of COVID 19, where people were highly infected at their occupations (35.58%), at houses (23.93%) and by traveling (12.88%). Noteworthy, according to this report, a large number (19.33%) of individuals did not know exactly how they were contaminated with SARS-CoV-2. Patients were most commonly treated by an antibiotic 95.09%, followed in second by corticosteroid 46.01%. Anti-viral drugs, remdesivir, and oxygenation are also needed for other patients. Among those, who were being treated, approximately 69.33% were isolated at home, 27.91% were being treated at dedicated COVID-19 hospitals. Finally, 96.63% were discharged without complications, and 0.03% has died.

CONCLUSION

This investigation concludes that males became more infected than females. Interestingly, both urban and rural people became nearly equally infected. It noticed community transmission of SARS-CoV-2, where people were highly infected at their workplaces. A higher rate of silent transmission indicates that more caution is needed to identify asymptomatic patients. Most of the infected people were isolated at home whereas nearly one-fourth were treated at hospitals. Clinically, antibiotics were the most widely used treatment. However, the majority of the patients were discharged without complications. The current investigation would be helpful to understand the clinical manifestations and socio-demographic situations during the second wave of the COVID-19 pandemic in Bangladesh.

Cytokine storm and histopathological findings in 60 cases of COVID-19-related death: from viral load research to immunohistochemical quantification of major players IL-1β, IL-6, IL-15 and TNF-α

This study involves the histological analysis of samples taken during autopsies in cases of COVID-19 related death to evaluate the inflammatory cytokine response and the tissue localization of the virus in various organs. In all the selected cases, SARS-CoV-2 RT-PCR on swabs collected from the upper (nasopharynx and oropharynx) and/or the lower respiratory (trachea and primary bronchi) tracts were positive. Tissue localization of SARS-CoV-2 was detected using antibodies against the nucleoprotein and the spike protein. Overall, we tested the hypothesis that the overexpression of proinflammatory cytokines plays an important role in the development of COVID-19-associated pneumonia by estimating the expression of multiple cytokines (IL-1β, IL-6, IL-10, IL-15, TNF-α, and MCP-1), inflammatory cells (CD4, CD8, CD20, and CD45), and fibrinogen. Immunohistochemical staining showed that endothelial cells expressed IL-1β in lung samples obtained from the COVID-19 group (p < 0.001). Similarly, alveolar capillary endothelial cells showed strong and diffuse immunoreactivity for IL-6 and IL-15 in the COVID-19 group (p < 0.001). TNF-α showed a higher immunoreactivity in the COVID-19 group than in the control group (p < 0.001). CD8 + T cells where more numerous in the lung samples obtained from the COVID-19 group (p < 0.001). Current evidence suggests that a cytokine storm is the major cause of acute respiratory distress syndrome (ARDS) and multiple organ failure and is consistently linked with fatal outcomes.

COVID-19 post-mortem findings: how the departed can teach us

We present an asthmatic 39 year old female frontline healthcare worker in contact with COVID-19 patients, who suffered from respiratory problems for a few days, after which she was found dead by her spouse. Post-mortem (PM) examination showed lung consolidation and histological evidence of diffuse alveolar damage (DAD), in form of hyaline membrane disease, as well as atypical cells, thrombi and fibrin plugs inside pulmonary capillaries. Swab sample testing for SARS-CoV-2 confirmed the infection status. SARS-CoV-2 is a novel coronavirus which first emerged in Wuhan, China, and PM is contributing immensely to uncovering the pathophysiological mechanism of this disease. SARS-CoV-2 enters host cells via the angiotensin-converting enzyme 2 (ACE2), and can lead to a fatal pneumonia characterized histologically by DAD (the most consistent PM finding). This is due to invasion by the virus of type II pneumocytes, which leads to the death of both type I and II pneumocytes and increased capillary permeability. This compromises gas exchange which can lead eventually to cardiorespiratory failure and death.

Human Coronaviruses: Counteracting the Damage by Storm

Over the past 18 years, three highly pathogenic human (h) coronaviruses (CoVs) have caused severe outbreaks, the most recent causative agent, SARS-CoV-2, being the first to cause a pandemic. Although much progress has been made since the COVID-19 pandemic started, much about SARS-CoV-2 and its disease, COVID-19, is still poorly understood. The highly pathogenic hCoVs differ in some respects, but also share some similarities in clinical presentation, the risk factors associated with severe disease, and the characteristic immunopathology associated with the progression to severe disease. This review aims to highlight these overlapping aspects of the highly pathogenic hCoVs-SARS-CoV, MERS-CoV, and SARS-CoV-2-briefly discussing the importance of an appropriately regulated immune response; how the immune response to these highly pathogenic hCoVs might be dysregulated through interferon (IFN) inhibition, antibody-dependent enhancement (ADE), and long non-coding RNA (lncRNA); and how these could link to the ensuing cytokine storm. The treatment approaches to highly pathogenic hCoV infections are discussed and it is suggested that a greater focus be placed on T-cell vaccines that elicit a cell-mediated immune response, using rapamycin as a potential agent to improve vaccine responses in the elderly and obese, and the potential of stapled peptides as antiviral agents.

The Role of Alveolar Edema in COVID-19

The coronavirus disease 2019 (COVID-19) has spread over the world for more than one year. COVID-19 often develops life-threatening hypoxemia. Endothelial injury caused by the viral infection leads to intravascular coagulation and ventilation-perfusion mismatch. However, besides above pathogenic mechanisms, the role of alveolar edema in the disease progression has not been discussed comprehensively. Since the exudation of pulmonary edema fluid was extremely serious in COVID-19 patients, we bring out a hypothesis that severity of alveolar edema may determine the size of poorly-ventilated area and the blood oxygen content. Treatments to pulmonary edema (conservative fluid management, exogenous surfactant replacements and ethanol–oxygen vapor therapy hypothetically) may be greatly helpful for reducing the occurrences of severe cases. Given that late mechanical ventilation may cause mucus (edema fluid) to be blown deep into the small airways, oxygen therapy should be given at the early stages. The optimal time and blood oxygen saturation (SpO₂) threshold for oxygen therapy are also discussed.

Full autopsy in a confirmed COVID-19 patient in Lagos, Nigeria - A case report

Objectives

To report the postmortem findings of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive individual who died in Lagos (Nigeria) in June 2020 and to investigate the cause, pathogenesis as well as pathological changes noticed during the examination.

Methods

Complete postmortem examination was performed according to standard procedures in a regular autopsy suite using personal protective equipment including N95 masks, goggles and disposable gowns. The diagnosis of coronavirus disease 2019 (COVID-19) was confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR) testing on postmortem nasopharyngeal swabs.

Results

A 47-year-old man with a medical history of well controlled hypertension and dyslipidaemia died after long hours of transportation for medical care in a hospital in Lagos. He tested positive for SARS-CoV-2 on ante- and postmortem nasopharyngeal swabs. Autopsy revealed pneumonia with diffuse alveolar damage, disseminated intravascular coagulopathy and hypovolaemic shock.

Conclusions

Autopsy can be performed on decedents who died from or with SARS-CoV-2 infection in a low resource environment such as ours. A standard autopsy room was used while deploying recommended infection prevention control and regular decontamination. The clinical details, autopsy findings such as diffuse alveolar damage and airway inflammation were consistent with a COVID-19 related pathology. While the decedent had ‘controlled’ co-morbidity, he succumbed to multi-organ failure occasioned by shock and disseminated intravascular coagulopathy.

Combining initial chest CT with clinical variables in differentiating coronavirus disease 2019 (COVID-19) pneumonia from influenza pneumonia

Coronavirus disease 2019 (COVID-19) has spread in more than 100 countries and regions around the world, raising grave global concerns. COVID-19 has a similar pattern of infection, clinical symptoms, and chest imaging findings to influenza pneumonia. In this retrospective study, we analysed clinical and chest CT data of 24 patients with COVID-19 and 79 patients with influenza pneumonia. Univariate analysis demonstrated that the temperature, systolic pressure, cough and sputum production could distinguish COVID-19 from influenza pneumonia. The diagnostic sensitivity and specificity for the clinical features are 0.783 and 0.747, and the AUC value is 0.819. Univariate analysis demonstrates that nine CT features, central-peripheral distribution, superior-inferior distribution, anterior-posterior distribution, patches of GGO, GGO nodule, vascular enlargement in GGO, air bronchogram, bronchiectasis within focus, interlobular septal thickening, could distinguish COVID-19 from influenza pneumonia. The diagnostic sensitivity and specificity for the CT features are 0.750 and 0.962, and the AUC value is 0.927. Finally, a multivariate logistic regression model combined the variables from the clinical variables and CT features models was made. The combined model contained six features: systolic blood pressure, sputum production, vascular enlargement in the GGO, GGO nodule, central-peripheral distribution and bronchiectasis within focus. The diagnostic sensitivity and specificity for the combined features are 0.87 and 0.96, and the AUC value is 0.961. In conclusion, some CT features or clinical variables can differentiate COVID-19 from influenza pneumonia. Moreover, CT features combined with clinical variables had higher diagnostic performance.