Pulmonary pathological features in coronavirus associated severe acute respiratory syndrome (SARS)

Pathogenesis and virulence of coronavirus disease: Comparative pathology of animal models for COVID-19

Animal models that can replicate clinical and pathologic features of severe human coronavirus infections have been instrumental in the development of novel vaccines and therapeutics. The goal of this review is to summarize our current understanding of the pathogenesis of coronavirus disease 2019 (COVID-19) and the pathologic features that can be observed in several currently available animal models. Knowledge gained from studying these animal models of SARS-CoV-2 infection can help inform appropriate model selection for disease modelling as well as for vaccine and therapeutic developments.

Small Airways Dysfunction and Lung Hyperinflation in Long COVID-19 Patients as Potential Mechanisms of Persistent Dyspnoea

BACKGROUND

Reticulation, ground glass opacities and post-infection bronchiectasis are present three months following hospitalisation in patients recovering from SARS-CoV-2 infection and are associated with the severity of acute infection. However, scarce data exist on small airways impairment and lung hyperinflation in patients with long COVID-19.

AIM

To evaluate small airways function and lung hyperinflation in previously hospitalised patients with long COVID-19 and their association with post-COVID-19 breathlessness.

METHODS

In total, 33 patients (mean ± SD, 53 ± 11 years) with long COVID-19 were recruited 149 ± 90 days following hospital discharge. Pulmonary function tests were performed and lung hyperinflation was defined as RV/TLC ≥ 40%. Small airways function was evaluated by measuring the closing volume (CV) and closing capacity (CC) using the single-breath nitrogen washout technique (SBN2W).

RESULTS

CC was 115 ± 28% pred. and open capacity (OC) was 90 ± 19. CC was abnormal in 13 patients (39%), CV in 2 patients (6.1%) and OC in 9 patients (27%). Lung hyperinflation was present in 15 patients, whilst the mean mMRC score was 2.2 ± 1.0. Lung hyperinflation was associated with CC (r = 0.772, p = 0.001), OC (r = 0.895, p = 0.001) and mMRC (r = 0.444, p = 0.010).

CONCLUSIONS

Long COVID-19 patients present with small airways dysfunction and lung hyperinflation, which is associated with persistent dyspnoea, following hospitalisation.

Long COVID symptoms after 8-month recovery: persistent static lung hyperinflation associated with small airway dysfunction

BACKGROUND

Limited research has investigated the relationship between small airway dysfunction (SAD) and static lung hyperinflation (SLH) in patients with post-acute sequelae of COVID-19 (PASC) especially dyspnea and fatigue.

METHODS

64 patients with PASC were enrolled between July 2020 and December 2022 in a prospective observational cohort. Pulmonary function tests, impulse oscillometry (IOS), and symptom questionnaires were performed two, five and eight months after acute infection. Multivariable logistic regression models were used to test the association between SLH and patient-reported outcomes.

RESULTS

SLH prevalence was 53.1% (34/64), irrespective of COVID-19 severity. IOS parameters and circulating CD4/CD8 T-cell ratio were significantly correlated with residual volume to total lung capacity ratio (RV/TLC). Serum CD8 + T cell count was negatively correlated with forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC) with statistical significance. Of the patients who had SLH at baseline, 57% continued to have persistent SLH after eight months of recovery, with these patients tending to be older and having dyspnea and fatigue. Post-COVID dyspnea was significantly associated with SLH and IOS parameters R5-R20, and AX with adjusted odds ratios 12.4, 12.8 and 7.6 respectively. SLH was also significantly associated with fatigue.

CONCLUSION

SAD and a decreased serum CD4/CD8 ratio were associated with SLH in patients with PASC. SLH may persist after recovery from infection in a substantial proportion of patients. SAD and dysregulated T-cell immune response correlated with SLH may contribute to the development of dyspnea and fatigue in patients with PASC.

Pulmonary Function, Computed Tomography Lung Abnormalities, and Small Airway Disease after COVID-19: 3-, 6-, and 9-Month Follow-Up

Background/Objectives: Coronavirus disease 2019 (COVID-19) course may differ among individuals-in particular, those with comorbidities may have severe pneumonia, requiring oxygen supplementation or mechanical ventilation. Post-COVID-19 long-term structural changes in imaging studies can contribute to persistent respiratory disturbance. This study aimed to investigate COVID-19 sequels affecting the possibility of persistent structural lung tissue abnormalities and their influence on the respiratory function of peripheral airways and gas transfer. Methods: Patients were divided into two groups according to severity grades described by the World Health Organization. Among the 176 hospitalized patients were 154 patients with mask oxygen supplementation and 22 patients with high-flow nasal cannula (HFNC) or mechanical ventilation. All tests were performed at 3, 6, and 9 months post-hospitalization. Results: Patients in the severe/critical group had lower lung volumes in FVC, FVC%, FEV1, FEV1%, LC, TLC%, and DLCO% at three months post-hospitalization. At 6 and 9 months, neither group had significant FVC and FEV1 value improvements. The MEF 25-75 values were not significantly higher in the mild/moderate group than in the severe/critical group at three months. There were weak significant correlations between FVC and FEV1, MEF50, MEF 75, plethysmography TLC, disturbances in DLCO, and total CT abnormalities in the severe/critical group at three months. In a mild/moderate group, there was a significant negative correlation between the spirometry, plethysmography parameters, and CT lesions in all periods. Conclusions: Persistent respiratory symptoms post-COVID-19 can result from fibrotic lung parenchyma and post-infectious stenotic small airway changes not visible in CT, probably due to persistent inflammation.

The Role of Neutrophil in COVID-19: Positive or Negative

BACKGROUND

Neutrophils are the first line of defense against pathogens. They are divided into multiple subpopulations during development and kill pathogens through various mechanisms. Neutrophils are considered one of the markers of severe COVID-19.

SUMMARY

In-depth research has revealed that neutrophil subpopulations have multiple complex functions. Different subsets of neutrophils play an important role in the progression of COVID-19.

KEY MESSAGES

In this review, we provide a detailed overview of the developmental processes of neutrophils at different stages and their recruitment and activation after SARS-CoV-2 infection, aiming to elucidate the changes in neutrophil subpopulations, characteristics, and functions after infection and provide a reference for mechanistic research on neutrophil subpopulations in the context of SARS-CoV-2 infection. In addition, we have also summarized research progress on potential targeted drugs for neutrophil immunotherapy, hoping to provide information that aids the development of therapeutic drugs for the clinical treatment of critically ill COVID-19 patients.

A case series of three patients with histologically proven post COVID-19 organizing pneumonia

Organizing pneumonia, a form of interstitial lung disease, may occur in patients who have recovered from COVID-19. In this article, we report three cases of post COVID-19 organizing pneumonia, proven histologically with transbronchial biopsies showing fibroblastic plugs in the alveolar spaces. Our patients received a range of 86-166 days of continuous corticosteroid therapy and all of them made excellent recovery.

Mitigation of influenza-mediated inflammation by immunomodulatory matrix-bound nanovesicles

Cytokine storm describes a life-threatening, systemic inflammatory syndrome characterized by elevated levels of proinflammatory cytokines and immune cell hyperactivation associated with multi-organ dysfunction. Matrix-bound nanovesicles (MBV) are a subclass of extracellular vesicle shown to down-regulate proinflammatory immune responses. The objective of this study was to assess the efficacy of MBV in mediating influenza-induced acute respiratory distress syndrome and cytokine storm in a murine model. Intravenous administration of MBV decreased influenza-mediated total lung inflammatory cell density, proinflammatory macrophage frequencies, and proinflammatory cytokines at 7 and 21 days following viral inoculation. MBV decreased long-lasting alveolitis and the proportion of lung undergoing inflammatory tissue repair at day 21. MBV increased the proportion of activated anti-viral CD4+ and CD8+ T cells at day 7 and memory-like CD62L+ CD44+, CD4+, and CD8+ T cells at day 21. These results show immunomodulatory properties of MBV that may benefit the treatment of viral-mediated pulmonary inflammation with applicability to other viral diseases such as SARS-CoV-2.

An Integrated Radiologic-Pathologic Understanding of COVID-19 Pneumonia

This article reviews the radiologic and pathologic findings of the epithelial and endothelial injuries in COVID-19 pneumonia to help radiologists understand the fundamental nature of the disease. The radiologic and pathologic manifestations of COVID-19 pneumonia result from epithelial and endothelial injuries based on viral toxicity and immunopathologic effects. The pathologic features of mild and reversible COVID-19 pneumonia involve nonspecific pneumonia or an organizing pneumonia pattern, while the pathologic features of potentially fatal and irreversible COVID-19 pneumonia are characterized by diffuse alveolar damage followed by fibrosis or acute fibrinous organizing pneumonia. These pathologic responses of epithelial injuries observed in COVID-19 pneumonia are not specific to SARS-CoV-2 but rather constitute universal responses to viral pneumonia. Endothelial injury in COVID-19 pneumonia is a prominent feature compared with other types of viral pneumonia and encompasses various vascular abnormalities at different levels, including pulmonary thromboembolism, vascular engorgement, peripheral vascular reduction, a vascular tree-in-bud pattern, and lung perfusion abnormality. Chest CT with different imaging techniques (eg, CT quantification, dual-energy CT perfusion) can fully capture the various manifestations of epithelial and endothelial injuries. CT can thus aid in establishing prognosis and identifying patients at risk for deterioration.

Mid-term pulmonary sequelae after hospitalisation for COVID-19: The French SISCOVID cohort

Background

Methods

Results

Conclusion

Celastrol: A lead compound that inhibits SARS-CoV-2 replication, the activity of viral and human cysteine proteases, and virus-induced IL-6 secretion

The global emergence of coronavirus disease 2019 (COVID-19) has caused substantial human casualties. Clinical manifestations of this disease vary from asymptomatic to lethal, and the symptomatic form can be associated with cytokine storm and hyperinflammation. In face of the urgent demand for effective drugs to treat COVID-19, we have searched for candidate compounds using in silico approach followed by experimental validation. Here we identified celastrol, a pentacyclic triterpene isolated from Tripterygium wilfordii Hook F, as one of the best compounds out of 39 drug candidates. Celastrol reverted the gene expression signature from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected cells and irreversibly inhibited the recombinant forms of the viral and human cysteine proteases involved in virus invasion, such as Mpro (main protease), PLpro (papain-like protease), and recombinant human cathepsin L. Celastrol suppressed SARS-CoV-2 replication in human and monkey cell lines and decreased interleukin-6 (IL-6) secretion in the SARS-CoV-2-infected human cell line. Celastrol acted in a concentration-dependent manner, with undetectable signs of cytotoxicity, and inhibited in vitro replication of the parental and SARS-CoV-2 variant. Therefore, celastrol is a promising lead compound to develop new drug candidates to face COVID-19 due to its ability to suppress SARS-CoV-2 replication and IL-6 production in infected cells.

Co-infection associated with SARS-CoV-2 and their management

SARS-CoV-2 was discovered in Wuhan, China and quickly spread throughout the world. This deadly virus moved from person to person, resulting in severe pneumonia, fever, chills and hypoxia. Patients are still experiencing problems after recovering from COVID-19. This review covers COVID-19 and associated issues following recovery from COVID-19, as well as multiorgan damage risk factors and treatment techniques. Several unusual illnesses, including mucormycosis, white fungus infection, happy hypoxia and other systemic abnormalities, have been reported in recovered individuals. In children, multisystem inflammatory syndrome with COVID-19 (MIS-C) is identified. The reasons for this might include uncontrollable steroid usage, reduced immunity, uncontrollable diabetes mellitus and inadequate care following COVID-19 recovery.

Lifestyle in Obese Individuals during the COVID-19 Pandemic

Background: Stay-at-home orders in response to the Coronavirus 2 (SARS-CoV-2) pandemic have forced abrupt changes to daily routines. The aim of this study is to describe the behavior of lifestyles of individuals with obesity on the waiting list for bariatric surgery in the Department of Medical and Surgical Sciences of University of Foggia during the COVID-19 pandemic. Materials and methods: From June 2020 to December 2020 an online survey format was administered to all the patients (n = 52) enrolled for bariatric surgery subjects with obesity, to obtain information about the COVID-19 pandemic’s impact on patients with obesity starting 9 March 2020 until 18 May 2020. Results: Our data showed that 58% of patients stated that the pandemic negatively affected their mood, 60% of patients confirmed that they changed their dietary behaviors during the stay-at-home period, as they consumed more unhealthy foods or spent less time cooking home cooked meals. In addition, 71% of patients stated that the closure of the gyms worsened their obesity condition and their mental well-being with an increase of a feeling of anxiety. Conclusions: Results showed that the COVID-19 pandemic has had a significant impact on health behaviors, including quality of life, mental health physical activity, weight maintenance, and consumption of sweets in obese patients.

Lung function and radiological findings 1 year after COVID-19: a prospective follow-up

BACKGROUND

The coronavirus disease (COVID-19) pandemic has already affected more than 400 million people, with increasing numbers of survivors. These data indicate that a myriad of people may be affected by pulmonary sequelae of the infection. The aim of this study was to evaluate pulmonary sequelae in patients with bilateral COVID-19 pneumonia according to severity 1 year after hospital discharge.

METHODS

COVID-FIBROTIC is a multicenter prospective observational cohort study for admitted patients with bilateral COVID-19 pneumonia. Pulmonary functional outcomes and chest computed tomography sequelae were analyzed 12 months after hospital discharge and we classified patients into three groups according to severity. A post hoc analysis model was designed to establish how functional test changed between groups and over time. A multivariable logistic regression model was created to study prognostic factors for lung diffusion impairment and radiological fibrotic-like changes at 12 months.

RESULTS

Among 488 hospitalized patients with COVID-19 pneumonia, 284 patients had completed the entire evaluation at 12 months. Median age was 60.5 ± 11.9 and 55.3% were men. We found between-group differences in male sex, length of hospital stay, radiological involvement and inflammatory laboratory parameters. The functional evaluation of pulmonary sequelae showed that severe patients had statistically worse levels of lung diffusion at 2 months but no between group differences were found in subsequent controls. At 12-month follow up, however, we found impaired lung diffusion in 39.8% unrelated to severity. Radiological fibrotic-like changes at 12 months were reported in 22.7% of patients (102/448), only associated with radiological involvement at admission (OR: 1.55, 95% CI 1.06-2.38; p = 0.02) and LDH (OR: 0.99, 95% CI 0.98-0.99; p = 0.046).

CONCLUSION

Our data suggest that a significant percentage of individuals would develop pulmonary sequelae after COVID 19 pneumonia, regardless of severity of the acute process. Trial registration clinicaltrials.gov NCT04409275 (June 1, 2020).

Immune-based therapeutic approaches in COVID-19

Coronavirus disease 2019 (COVID-19) is a viral disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a member of the Coronaviridae family. On March 11, 2020 the World Health Organization (WHO) has named the newly emerged rapidly-spreading epidemic as a pandemic. Besides the risk-reduction measures such as physical and social distancing and vaccination, a wide range of treatment modalities have been developed; aiming to fight the disease. The immune system is known as a double-edged sword in COVID-19 pathogenesis, with respect to its role in eliminating the pathogen and in inducing complications such as cytokine storm syndrome. Hence, immune-based therapeutic approaches have become an interesting field of COVID-19 research, including corticosteroids, intravenous immunoglobulins (IVIG), interferon therapy, and more COVID-19-specific approaches such as anti-SARS-CoV-2-monoclonal antibodies. Herein, we did a comprehensive review on immune-based therapeutic approaches for COVID-19. DATA AVAILABILITY STATEMENT: Not applicable.

Radiologically suspected COVID‑19‑associated organizing pneumonia responding well to corticosteroids: A report of two cases and a review of the literature

Organizing pneumonia (OP) is a type of diffuse interstitial lung disease, which may be induced in the context of several clinical conditions, such as drug reactions, infections, autoimmune diseases and cancer. Coronavirus disease 2019 (COVID-19)-associated OP has been reported as a late-stage consequence of the infection or a histological form of COVID-19-associated pneumonia. Autopsies and postmortem lung biopsies have demonstrated that the majority of patients with COVID-19-associated pneumonia develop secondary OP, and COVID-19-associated pneumonia and OP have common radiological features. The diagnosis of COVID-19-associated OP should be suspected in patients with severe acute respiratory syndrome coronavirus 2 infection who exhibit clinical deterioration despite optimal care, or who have aggravating symptoms following an initial recovery. The use of corticosteroids is a typical treatment for OP. However, to date, at least to the best of our knowledge, there are a few reports regarding the role of corticosteroids in COVID-19-associated pneumonia; thus, the optimal time for administration, the dose and treatment duration have not yet been determined. The present study presents two cases of patients with COVID-19, who exhibited clinical deterioration following the initial phase of infection and with radiological characteristics of OP who received corticosteroids and had a favorable outcome. The early diagnosis of COVID-19-associated OP may lead to targeted treatment, decreased requirements for ventilatory support and an improved survival rate.

Multisystem Inflammatory Syndrome and Autoimmune Diseases Following COVID-19: Molecular Mechanisms and Therapeutic Opportunities

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), has led to huge concern worldwide. Some SARS-CoV-2 infected patients may experience post–COVID-19 complications such as multisystem inflammatory syndrome, defined by symptoms including fever and elevated inflammatory markers (such as elevation of C reactive protein (CRP), erythrocyte sedimentation rate, fibrinogen, procalcitonin test, D-dimer, ferritin, lactate dehydrogenase or IL-6, presence of neutrophilia, lymphopenia, decreased albumin, and multiple organ dysfunction). Post–COVID-19 complications may also manifest as autoimmune diseases such as Guillain-Barré syndrome and systemic lupus erythematosus. Signaling disorders, increased inflammatory cytokines secretion, corticosteroid use to treat COVID-19 patients, or impaired immune responses are suggested causes of autoimmune diseases in these patients. In this review, we discuss the molecular and pathophysiological mechanisms and therapeutic opportunities for multisystem inflammatory syndrome and autoimmune diseases following SARS-CoV-2 infection with the aim to provide a clear view for health care providers and researchers.

Late Complications of COVID-19: A Morphologic, Imaging, and Droplet Digital Polymerase Chain Reaction Study of Lung Tissue

CONTEXT

Studies of lungs in patients with COVID-19 have focused on early findings.

OBJECTIVE

To systematically study histopathologic, imaging features and presence of SARSCoV-2 RNA in lung tissue from patients in later stages of COVID-19.

DESIGN

Autopsies, explants, surgical lung biopsies; and transbronchial, cryo, and needle biopsies were studied from patients with COVID-19, whose onset of symptoms/confirmed diagnosis was more than 28 days before the procedure. Available images were reviewed. Reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) for SARS-CoV-2 RNA was performed on lung tissue.

RESULTS

Forty-four specimens (43 patients, median age 59.3 years, 26 [60.5%] male) showed features of acute lung injury (ALI) in 39 (88.6%), predominantly organizing pneumonia (OP) and diffuse alveolar damage (DAD), up to 298 days after onset of COVID-19. Fibrotic changes were found in 33 specimens (75%), most commonly fibrotic DAD (N=22) and cicatricial OP (N=12). Time between acquiring COVID-19 and specimen was shorter in patients with diffuse ALI (median 61.5 days) compared to patients with focal (140 days) or no ALI (130 days) (P=.009). Sixteen (of 20, 80%) SARS-CoV-2 RT-ddPCR tests were positive, up to 174 days after COVID-19 onset. Time between COVID-19 onset and most recent CT in patients with consolidation on imaging was shorter (median 43.0 days) versus patients without consolidation (87.5 days; P=.02). Reticulations were associated with longer time after COVID-19 onset to CT (median 82 days vs 23.5 days, P=.006).

CONCLUSIONS

ALI and SARS-CoV-2 RNA can be detected in patients with COVID-19 for many months. ALI may evolve into fibrotic interstitial lung disease.

Curse of La Corona: unravelling the scientific and psychological conundrums of the 21st century pandemic

Microbes possess a tremendous potential to interact with their surroundings and have continued to shape the future of all life forms existing on earth. Of all the groups of microbes, viruses are the most nefarious creatures which cannot be solely classified as living or non-living but still pose the greatest threats to the biosphere. Viruses are minuscule, diverse and are probably the only entities that exhibit non-mutualistic association with other lifeforms while retaining their ability to infect and hijack any of the existing living being on the planet. The latest global devastation, caused by novel SARS-CoV-2, is unparalleled in the last century. This review encompasses the mysterious origin of this virus by tracking its lineage, which may help to decode the conundrum of SARS-CoV-2 and shed more light on its epidemiology. The implications and the challenge posed by this virus to the scientific community to the medical community and the economy at large are reflected. Also discussed is the paradigm shift brought upon by the COVID-19 pandemic on the human psyche and their behaviour.

Lung Ultrasound as a First-Line Test in the Evaluation of Post-COVID-19 Pulmonary Sequelae

Background: Interstitial lung sequelae are increasingly being reported in survivors of COVID-19 pneumonia. An early detection of these lesions may help prevent the development of irreversible lung fibrosis. Lung ultrasound (LUS) has shown high diagnostic accuracy in interstitial lung disease (ILD) and could likely be used as a first-line test for post-COVID-19 lung sequelae. Methods: Single-center observational prospective study. Follow-up assessments of consecutive patients hospitalized for COVID-19 pneumonia were conducted 2-5 months after the hospitalization. All patients underwent pulmonary function tests (PFTs), high-resolution computed tomography (HRCT), and LUS. Radiological alterations in HRCT were quantified using the Warrick score. The LUS score was obtained by evaluating the presence of pathological B-lines in 12 thoracic areas (range, 0-12). The correlation between the LUS and Warrick scores was analyzed. Results: Three hundred and fifty-two patients who recovered from COVID-19 pneumonia were recruited between July and September 2020. At follow-up, dyspnea was the most frequent symptom (69.3%). FVC and DLCO alterations were present in 79 (22.4%) and 234 (66.5%) patients, respectively. HRCT showed relevant interstitial lung sequelae (RILS) in 154 (43.8%) patients (Warrick score ≥ 7). The LUS score was strongly correlated with the HRCT Warrick score (r = 0.77) and showed a moderate inverse correlation with DLCO (r = -0.55). The ROC curve analysis revealed that a LUS score ≥ 3 indicated an excellent ability to discriminate patients with RILS (sensitivity, 94.2%; specificity, 81.8%; negative predictive value, 94.7%). Conclusions: LUS could be implemented as a first-line procedure in the evaluation of Post-COVID-19 interstitial lung sequelae. A normal LUS examination rules out the presence of these sequelae in COVID-19 survivors, avoiding the need for additional diagnostic tests such as HRCT.

Chemokine-Based Therapeutics for the Treatment of Inflammatory and Fibrotic Convergent Pathways in COVID-19

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the SARS-CoV-2 betacoronavirus and has taken over 761,426 American lives as of the date of publication and will likely result in long-term, if not permanent, tissue damage for countless patients. COVID-19 presents with diverse and multisystemic pathologic processes, including a hyperinflammatory response, acute respiratory distress syndrome (ARDS), vascular injury, microangiopathy, tissue fibrosis, angiogenesis, and widespread thrombosis across multiple organs, including the lungs, heart, kidney, liver, and brain. C-X-C chemokines contribute to these pathologies by attracting inflammatory mediators, the disruption of endothelial cell integrity and function, and the initiation and propagation of the cytokine storm. Among these, CXCL10 is recognized as a critical contributor to the hyperinflammatory state and poor prognosis in COVID-19. CXCL10 is also known to regulate growth factor-induced fibrosis, and recent evidence suggests the CXCL10-CXCR3 signaling system may be vital in targeting convergent pro-inflammatory and pro-fibrotic pathways. This review will explore the mechanistic role of CXCL10 and related chemokines in fibrotic complications associated with COVID-19 and the potential of CXCL10-targeted therapeutics for early intervention and long-term treatment of COVID-19-induced fibrosis.

Comparison of pirfenidone and corticosteroid treatments at the COVID-19 pneumonia with the guide of artificial intelligence supported thoracic computed tomography

AIM

We aimed to investigate the effect of short-term pirfenidone treatment on prolonged COVID-19 pneumonia.

METHOD

Hospital files of patients hospitalised with a diagnosis of critical COVID-19 pneumonia from November 2020 to March 2021 were retrospectively reviewed. Chest computed tomography images taken both before treatment and 2 months after treatment, demographic characteristics and laboratory parameters of patients receiving pirfenidone + methylprednisolone (n = 13) and only methylprednisolones (n = 9) were recorded. Pulmonary function tests were performed after the second month of the treatment. CT involvement rates were determined by machine learning.

RESULTS

A total of 22 patients, 13 of whom (59.1%) were using methylprednisolone + pirfenidone and 9 of whom (40.9%) were using only methylprednisolone were included. When the blood gas parameters and pulmonary function tests of the patients were compared at the end of the second month, it was found that the FEV1, FEV1%, FVC and FVC% values were statistically significantly higher in the methylprednisolone + pirfenidone group compared with the methylprednisolone group (P = .025, P = .012, P = .026 and P = .017, respectively). When the rates of change in CT scans at diagnosis and second month of treatment were examined, it was found that the involvement rates in the methylprednisolone + pirfenidone group were statistically significantly decreased (P < .001).

CONCLUSION

Antifibrotic agents can reduce fibrosis that may develop in the future. These can also help dose reduction and/or non-use strategy for methylprednisolone therapy, which has many side effects. Further large series and randomised controlled studies are needed on this subject.

Effectiveness of Pulmonary Rehabilitation in Interstitial Lung Disease, Including Coronavirus Diseases: A Systematic Review and Meta-analysis

OBJECTIVE

A meta-analysis of randomized controlled trials (RCTs) was conducted to determine the effect of pulmonary rehabilitation on functional capacity and quality of life in interstitial lung diseases, including those caused by coronaviruses.

DATA SOURCES

MEDLINE, EMBASE, SPORTDiscus, Cochrane Library, Web of Science, and MedRxiv from inception to November 2020 were searched to identify documents.

STUDY SELECTION

Publications investigating the effect of pulmonary rehabilitation on lung function (forced vital capacity [FVC]), exercise capacity (6-minute walk distance [6MWD]), health related quality of life (HRQOL), and dyspnea were searched.

DATA EXTRACTION

The data were extracted into predesigned data extraction tables. Risk of bias was evaluated with the Cochrane Risk of Bias tool (RoB 2.0).

DATA SYNTHESIS

A total of 11 RCTs with 637 interstitial lung disease patients were eligible for analyses. The pooled effect sizes of the association for pulmonary rehabilitation were 0.37 (95% confidence interval [CI], 0.02-0.71) for FVC, 44.55 (95% CI, 32.46-56.64) for 6MWD, 0.52 (95% CI, 0.22-0.82) for HRQOL, and 0.39 (95% CI, -0.08 to 0.87) for dyspnea. After translating these findings considering clinical improvements, pulmonary rehabilitation intervention increased predicted FVC by 5.5%, the 6MWD test improved by 44.55 m, and HRQOL improved by 3.9 points compared with baseline values. Results remained similar in sensitivity analyses.

CONCLUSIONS

Although specific evidence for pulmonary rehabilitation of coronavirus disease 2019 patients has emerged, our data support that interstitial lung disease rehabilitation could be considered as an effective therapeutic strategy to improve the functional capacity and quality of life in this group of patients.

Autopsy-Based Pulmonary and Vascular Pathology: Pulmonary Endotheliitis and Multi-Organ Involvement in COVID-19 Associated Deaths

BACKGROUND

Findings from autopsies have provided evidence on systemic microvascular damage as one of the underlying mechanisms of Coronavirus disease 2019 (CO-VID-19). The aim of this study was to correlate autopsy-based cause of death in SARS-CoV-2, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive patients with chest imaging and severity grade of pulmonary and systemic morphological vascular pathology.

METHODS

Fifteen SARS-CoV-2 positive autopsies with clinically distinct presentations (age 22-89 years) were retrospectively analyzed with focus on vascular, thromboembolic, and ischemic changes in pulmonary and in extrapulmonary sites. Eight patients died due to COVID-19 associated respiratory failure with diffuse alveolar damage in various stages and/or multi-organ failure, whereas other reasons such as cardiac decompensation, complication of malignant tumors, or septic shock were the cause of death in 7 further patients. The severity of gross and histopathological changes was semi-quantitatively scored as 0 (absent), 1 (mild), and 3 (severe). Severity scores between the 2 groups were correlated with selected clinical parameters, initial chest imaging, autopsy-based cause of death, and compared using Pearson χ2 and Mann-Whitney U tests.

RESULTS

Severe pulmonary endotheliitis (p = 0.031, p = 0.029) and multi-organ involvement (p = 0.026, p = 0.006) correlated significantly with COVID-19 associated death. Pulmonary microthrombi showed limited statistical correlation, while tissue necrosis, gross pulmonary embolism, and bacterial superinfection did not differentiate the 2 study groups. Chest imaging at hospital admission did not differ either.

CONCLUSIONS

Extensive pulmonary endotheliitis and multi-organ involvement are characteristic autopsy features in fatal CO-VID-19 associated deaths. Thromboembolic and ischemic events and bacterial superinfections occur frequently in SARS-CoV-2 infection independently of outcome.

Organizing pneumonia following Covid19 pneumonia

The potential mid-term and long-term consequences after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections are as yet unknown. This is the first report of bronchoscopically verified organizing pneumonia as a complication of coronavirus disease 2019 (Covid19). It caused persisting dyspnea, impaired pulmonary function, and radiological abnormalities over 5 weeks after onset of symptoms. While organizing pneumonia frequently requires treatment with systemic corticosteroids, in this case it resolved spontaneously without treatment after 6 weeks. Healthcare professionals should consider organizing pneumonia in patients with persisting respiratory symptoms after Covid19.

Does COVID-19 pneumonia signify secondary organizing pneumonia?: A narrative review comparing the similarities between these two distinct entities

Multiple observational studies have described the similarities between COVID-19 pneumonia and organizing pneumonia (OP). These two entities clinically manifest with mild and subacute respiratory symptoms, often with a delayed diagnosis due to the atypical ARDS and silent hypoxemia presentation. Radiological features are often indistinguishable between the two. With the increase in antemortem lung biopsies and autopsies being performed, more histopathological findings of OP and its variant, acute fibrinous and organizing pneumonia (AFOP), are being diagnosed. These entities are known complications of viral infections as a delayed immunological process, explaining the favorable response to corticosteroids. Clinicians should be vigilant to diagnose this under-recognized entity of secondary OP in people with COVID-19 when clinical deterioration occurs, especially with compatible radiologic findings and recent cessation of corticosteroids. Despite the proven benefits of corticosteroids in treating COVID-19, treatment approaches can be more effective as OP often requires higher doses and a more prolonged therapy duration for remission and preventing relapses. The purpose of our narrative review is to compare the similarities between COVID-19 pneumonia and OP, emphasizing the clinical, radiological, and histopathological features based on the evidence available in the literature.

Rehabilitation nach COVID-19-Erkrankung

6 months following an acute infection with SARS-CoV-2 virus with a moderate or severe course of Corona Virus Disease 2019 (COVID-19), a majority of patients is still suffering from sequelae which are defined as „post COVID syndrome“ or „long COVID“. Symptoms are heterogenous and can be of respiratory, neurological, musculoskeltal, cardiovascular, mental or cognitive nature. As the virus entrance into the organism via the lungs, this organ is involved in a unique manner. As a consequence of COVID-19, abnormalities of the lungs may lead to impaired gas exchange and result in a reduced blood oxygenation, especially during exercise. In order to address the intensity and diversity of symptoms, an inpatient pulmonary rehabilitation program is recommended. Beside diagnostics and pharmaceutical optimization, the multimodal approach includes several therapeutic components like exercise training, breathing therapy and psychological counseling. According to constantly new insights into this field, therapies have to be adapted permanently. An optimal postacute care, which ideally already starts during hospital stay, targets the improvement of exercise capacity, health-related quality of life as well as a reduction of ongoing symptoms in order to optimize patients daily life self-sufficiency.

COVID-19: a Disease with a Potpourri of Histopathologic Findings-a Literature Review and Comparison to the Closely Related SARS and MERS

Since the coronavirus disease 2019 (COVID-19) pandemic has hit the entire world, there is ample knowledge regarding its clinical course and prognostic biomarkers. Still, the pathophysiology of COVID-19 is poorly understood. Since the first guidelines published in February 2020 for autopsy of both confirmed and suspected COVID-19 cases, there has been an increasing number of autopsies and literature reporting histopathological findings. However, our knowledge about the immunological response of various organ systems to the virus, as well as response patterns, is inadequate but is essential to understand and initiate timely and targeted antiviral, anti-inflammatory, or anticoagulative therapy. Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is primarily considered a respiratory virus, current evidence shows that it causes life-threatening complications in almost all organ systems including the heart, brain, kidney, spleen, liver, and eyes. Hence, in this article, we reviewed the published case reports and case series in order to increase our understanding of COVID-19 pathophysiology. The main histopathological findings of the lungs include diffuse alveolar damage with activated type II pneumocytes, fibroblasts, protein-rich exudate, and hyaline membranes. Other significant histopathological findings include cardiomegaly, right ventricular dilation, splenic pulp atrophy, kidneys with severe podocytopathy, and collapsing glomerulopathy, and the brain showed hypoxic changes in the cerebellum and cerebrum. Furthermore, in this review, we also explained different pathological findings of SARS-CoV and MERS and compared them to SARS-CoV-2. This comprehensive review will improve our understanding of COVID-19 pathophysiology and various disease stages, hence promoting the application of targeted therapy.

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.

Current status of the COVID-19 and male reproduction: A review of the literature

BACKGROUND

Coronavirus disease 2019 (COVID-19), which causes serious respiratory illnesses such as pneumonia and lung failure, was first reported in mid-December 2019 in China and has spread around the world. In addition to causing serious respiratory illnesses such as pneumonia and lung failure, there have been conflicting reports about the presence of SARS-CoV-2 in the semen of patients who were previously diagnosed with COVID-19 and possible implications for the male reproductive tract.

OBJECTIVE

The goal for the present study was to review the current status of the literature concerning COVID-19 and male reproduction.

MATERIAL AND METHODS

An electronic literature search was done by using PubMed and Google Scholar databases. Relevant papers, concerning SARS-COV-2 and COVID-19 and male reproduction, published between January 2020 and December 2020 were selected, analyzed and eventually included in the present literature review.

RESULTS

SARS-CoV-2 may infect any cell type expressing angiotensin-converting enzyme 2 (ACE2), including reproductive cells. Besides the presence of the SARS-CoV-2 receptor, the expression of host proteases, such as transmembrane serine protease 2 (TMPRSS2), is needed to cleave the viral S protein, allowing permanent fusion of the viral and host cell membranes. Here, we aimed to review the current status of the literature concerning COVID-19 and male reproduction. The lack of co-expression of ACE2 and TMPRSS2 in the testis suggests that sperm cells may not be at increased risk of viral entry and spread. However, the presence of orchitis in COVID-19-confirmed patients and compromised sex-related hormonal balance among these patients intrigues reproductive medicine.

DISCUSSION

SARS-CoV-2 may use alternate receptors to enter certain cell types, or the expression of ACE2 and TMPRSS2 may not be detected in healthy individuals.

CONCLUSION

COVID-19 challenges all medical areas, including reproductive medicine. It is not yet clear what effects, if any, the COVID-19 pandemic will have on male reproduction. Further research is needed to understand the long-term impact of SARS-CoV-2 on male reproductive function.

Autopsies in pandemics - a perspective on barriers and benefits. Is it time for a revival?

Influenza virus and coronavirus pandemics regularly sweep the globe, at great cost of health and economy. Our aim was to conduct a PubMed search for autopsy studies on influenza and coronavirus to investigate the contribution of autopsies during pandemics, focussing on autopsy methods and procedures and the role of autopsy findings in pandemics. The retrieved autopsy studies generally relied on microscopy, polymerase chain reaction (PCR), immunostaining and electron microscopy. Most were small and reported on lung effects, including diffuse alveolar damage (DAD), pneumonia and tracheobronchitis. Antibiotic therapy has diminished a role for bacterial pneumonia, whereas obesity is an emerging risk factor. Autopsy studies have provided new insights into coronavirus disease 2019 (COVID-19) treatments like anti-coagulative therapy. Unfortunately, autopsies during pandemics are hampered by lack of guidelines, facilities and expertise for handling potentially infectious corpses and by widely varying recommendations for personal protective equipment and procedures. The Department of Forensic Pathology, at the Forensic Institute, at the University of Copenhagen in Denmark has, in collaboration with the Department of Pathology, Rigshospitalet, Copenhagen, initiated a prospective observational study on COVID-19-related deaths encompassing postmortem imaging, standardized autopsy procedures/reporting and extensive tissue sampling for histological, chemical, microbiological and genetic analysis. The study involves a diverse array of research groups at the University of Copenhagen, and the clinical field.

Multidrug Resistence Prevalence in COVID Area

Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is often complicated by severe acute respiratory syndrome. The new coronavirus outbreak started in China in December 2019 and rapidly spread around the world. The high diffusibility of the virus was the reason for the outbreak of the pandemic viral disease, reaching more than 100 million infected people globally by the first three months of 2021. In the various treatments used up to now, the use of antimicrobial drugs for the management, especially of bacterial co-infections, is very frequent in patients admitted to intensive care. In addition, critically ill patients with SARS-CoV-2 infection are subjected to prolonged mechanical ventilation and other therapeutic procedures often responsible for developing hospital co-infections due to multidrug-resistant bacteria. Co-infections contribute to the increase in the morbidity-mortality of viral respiratory infections. We performed this study to review the recent articles published on the antibiotic bacterial resistance and viruses to predict risk factors of coronavirus disease 2019 and to assess the multidrug resistance in patients hospitalized in the COVID-19 area.

Autopsy findings in COVID-19-related deaths: a literature review

Although many clinical reports have been published, little is known about the pathological post-mortem findings from people who have died of the novel coronavirus disease. The need for postmortem information is urgent to improve patient management of mild and severe illness, and treatment strategies. The present systematic review was carried out according to the Preferred Reporting Items for Systematic Review (PRISMA) standards. A systematic literature search and a critical review of the collected studies were conducted. An electronic search of PubMed, Science Direct Scopus, Google Scholar, and Excerpta Medica Database (EMBASE) from database inception to June 2020 was performed. We found 28 scientific papers; the total amount of cases is 341. The major histological feature in the lung is diffuse alveolar damage with hyaline membrane formation, alongside microthrombi in small pulmonary vessels. It appears that there is a high incidence of deep vein thrombosis and pulmonary embolism among COVID-19 decedents, suggesting endothelial involvement, but more studies are needed. A uniform COVID-19 post-mortem diagnostic protocol has not yet been developed. In a time in which international collaboration is essential, standardized diagnostic criteria are fundamental requirements.

The contributory role of lymphocyte subsets, pathophysiology of lymphopenia and its implication as prognostic and therapeutic opportunity in COVID-19

The incidence of the novel coronavirus disease (COVID-19) outbreak caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has brought daunting complications for people as well as physicians around the world. An ever-increasing number of studies investigating the characteristics of the disease, day by day, is shedding light on a new feature of the virus with the hope that eventually these efforts lead to the proper treatment. SARS-CoV-2 activates antiviral immune responses, but in addition may overproduce pro-inflammatory cytokines, causing uncontrolled inflammatory responses in patients with severe COVID-19. This condition may lead to lymphopenia and lymphocyte dysfunction, which in turn, predispose patients to further infections, septic shock, and severe multiple organ dysfunction. Therefore, accurate knowledge in this issue is important to guide clinical management of the disease and the development of new therapeutic strategies in patients with COVID-19. In this review, we provide a piece of valuable information about the alteration of each subtype of lymphocytes and important prognostic factors associated with these cells. Moreover, through discussing the lymphopenia pathophysiology and debating some of the most recent lymphocyte- or lymphopenia-related treatment strategies in COVID-19 patients, we tried to brightening the foreseeable future for COVID-19 patients, especially those with severe disease.

Human-Based Advanced in vitro Approaches to Investigate Lung Fibrosis and Pulmonary Effects of COVID-19

The coronavirus disease 2019 (COVID-19) pandemic has caused considerable socio-economic burden, which fueled the development of treatment strategies and vaccines at an unprecedented speed. However, our knowledge on disease recovery is sparse and concerns about long-term pulmonary impairments are increasing. Causing a broad spectrum of symptoms, COVID-19 can manifest as acute respiratory distress syndrome (ARDS) in the most severely affected patients. Notably, pulmonary infection with Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), the causing agent of COVID-19, induces diffuse alveolar damage (DAD) followed by fibrotic remodeling and persistent reduced oxygenation in some patients. It is currently not known whether tissue scaring fully resolves or progresses to interstitial pulmonary fibrosis. The most aggressive form of pulmonary fibrosis is idiopathic pulmonary fibrosis (IPF). IPF is a fatal disease that progressively destroys alveolar architecture by uncontrolled fibroblast proliferation and the deposition of collagen and extracellular matrix (ECM) proteins. It is assumed that micro-injuries to the alveolar epithelium may be induced by inhalation of micro-particles, pathophysiological mechanical stress or viral infections, which can result in abnormal wound healing response. However, the exact underlying causes and molecular mechanisms of lung fibrosis are poorly understood due to the limited availability of clinically relevant models. Recently, the emergence of SARS-CoV-2 with the urgent need to investigate its pathogenesis and address drug options, has led to the broad application of in vivo and in vitro models to study lung diseases. In particular, advanced in vitro models including precision-cut lung slices (PCLS), lung organoids, 3D in vitro tissues and lung-on-chip (LOC) models have been successfully employed for drug screens. In order to gain a deeper understanding of SARS-CoV-2 infection and ultimately alveolar tissue regeneration, it will be crucial to optimize the available models for SARS-CoV-2 infection in multicellular systems that recapitulate tissue regeneration and fibrotic remodeling. Current evidence for SARS-CoV-2 mediated pulmonary fibrosis and a selection of classical and novel lung models will be discussed in this review.

Pulmonary function and radiological features 4 months after COVID-19: first results from the national prospective observational Swiss COVID-19 lung study

Background

The infectious coronavirus disease 2019 (COVID-19) pandemic is an ongoing global healthcare challenge. Up to one-third of hospitalised patients develop severe pulmonary complications and acute respiratory distress syndrome. Pulmonary outcomes following COVID-19 are unknown.

Methods

The Swiss COVID-19 lung study is a multicentre prospective cohort investigating pulmonary sequelae of COVID-19. We report on initial follow-up 4 months after mild/moderate or severe/critical COVID-19 according to the World Health Organization severity classification.

Results

113 COVID-19 survivors were included (mild/moderate n=47, severe/critical n=66). We confirmed several comorbidities as risk factors for severe/critical disease. Severe/critical disease was associated with impaired pulmonary function, i.e. diffusing capacity of the lung for carbon monoxide (D_LCO) % predicted, reduced 6-min walk distance (6MWD) and exercise-induced oxygen desaturation. After adjustment for potential confounding by age, sex and body mass index (BMI), patients after severe/critical COVID-19 had a D_LCO 20.9% pred (95% CI 12.4–29.4% pred, p=0.01) lower at follow-up. D_LCO % pred was the strongest independent factor associated with previous severe/critical disease when age, sex, BMI, 6MWD and minimal peripheral oxygen saturation at exercise were included in the multivariable model (adjusted odds ratio per 10% predicted 0.59, 95% CI 0. 37–0.87; p=0.01). Mosaic hypoattenuation on chest computed tomography at follow-up was significantly associated with previous severe/critical COVID-19 including adjustment for age and sex (adjusted OR 11.7, 95% CI 1.7–239; p=0.03).

Conclusions

4 months after severe acute respiratory syndrome coronavirus 2 infection, severe/critical COVID-19 was associated with significant functional and radiological abnormalities, potentially due to small-airway and lung parenchymal disease. A systematic follow-up for survivors needs to be evaluated to optimise care for patients recovering from COVID-19.

COVID-19 pulmonary sequelae are unknown. The Swiss COVID-19 lung study reports on initial follow-up findings. Severe or critical COVID-19 was associated with significant functional impairment and radiological abnormalities after 4 months.https://bit.ly/34sNVvi

The Beneficial Effects of QIAPI 1® against Pentavalent Arsenic-Induced Lung Toxicity a Hypothetical Model for SARS CoV2-Induced Lung Toxicity

Exposure to environmental toxicants such as Arsenic (As) can result in As-induced alterations in immune regulators. Consequently, people who are more prone to viral infections like influenza A or B, H1N1, SARS CoV (Severe Acute Respiratory Syndrome Coronavirus), and SARS CoV2 may develop susceptibility to immune responses in their lungs because our previous reports delineated the ability of QIAPI 1®, a melanin precursor, to dissociate water molecules with simultaneous therapeutic efficacy against central nervous system (CNS) diseases, retinopathy, and As-induced renal toxicity. Given the commonalities of lung pathology of SARS CoV and As-induced toxicity, the aim of this study is to decipher the efficacy of QIAPI 1® against pentavalent As-induced lung toxicity by examining the pulmonary pathology. Hematoxylin & Eosin (H&E) staining was used for ascertaining the lung pathology in Wistar rat models. Animals were divided into 3 groups: control group, group treated with pentavalent As, and a group treated with pentavalent As and QIAPI 1®. There were no significant changes in lung histopathology in the control group as indicated by intact morphology. As-treated group revealed damage to the histoarchitecture with pulmonary edema, interstitial fibrosis, diffuse alveolar damage, Bronchiolitis obliterans organizing pneumonia (BOOP)-lesions, formation of hyaline membrane, multinucleated giant pneumocytes, atypical pneumocytes, inflammatory cell infiltration, and interstitial edema. The group treated with As and QIAPI 1® significantly associated with mitigated histological signs of lung inflammation induced by Arsenic. Therefore, QIAPI 1® can be recommended as antagonistic to As-induced lung toxicity. In conclusion, this model could be preferred as a hypothetical model to examine the efficacy of QIAPI 1® in SARS CoV2-induced pulmonary damage. Future studies are warranted to delineate the efficacy of QIAPI 1® against SARS CoV and SARS CoV2 lung pathology.

Can bilirubin nanomedicine become a hope for the management of COVID-19?

Bilirubin has been proven to possess significant anti-inflammatory, antioxidant and antiviral activities. Recently, it has been postulated as a metabolic hormone. Further, moderately higher levels of bilirubin are positively associated with reduced risk of cardiovascular diseases, diabetes, metabolic syndrome and obesity. However, due to poor solubility the therapeutic delivery of bilirubin remains a challenge. Nanotechnology offers unique advantages which may be exploited for improved delivery of bilirubin to the target organ with reduced risk of systemic toxicity. Herein, we postulate the use of intravenous administration or inhalational delivery of bilirubin nanomedicine (BNM) to combat systemic dysfunctions associated with COVID-19, owing to the remarkable preclinical efficacy and optimistic results of various clinical studies of bilirubin in non-communicable disorders. BNM may be used to harness the proven preclinical pharmacological efficacy of bilirubin against COVID-19 related systemic complications.

Autopsy Tool in Unknown Diseases: The Experience with Coronaviruses (SARS-CoV, MERS-CoV, SARS-CoV-2)

In the last two decades, three unknown pathogens have caused outbreaks, generating severe global health concerns. In 2003, after nucleic acid genotyping, a new virus was named severe acute respiratory syndrome coronavirus (SARS-CoV). After nine years, another coronavirus emerged in the middle east and was named MERS-CoV (Middle East Respiratory Syndrome-Coronavirus). Finally, in December 2019, a new unknown coronavirus was isolated from a cluster of patients and was named SARS-CoV-2 (COVID-19, coronavirus disease 2019). This review aims to propose a complete overview of autopsy in the three coronaviruses over the past two decades, showing its pivotal role in the management of unknown diseases. A total of 116 studies fulfilled the inclusion criteria: 14 studies were collected concerning SARS-CoV (87 autopsy reports, from Asian and American countries), 2 studies for MERS-CoV (2 autopsy reports, from Middle-East Asian countries), and 100 studies on SARS-CoV-2 (930 autopsy reports). Analyzing the data obtained on COVID-19, based on the country criterion, a large number of post-mortem investigation were performed in European countries (580 reports), followed by American countries (251 reports). It is interesting to note that no data were found from the Oceanic countries, maybe because of the minor involvement of the outbreak. In all cases, autopsy provided much information about each unknown coronavirus. Despite advanced technologies in the diagnostic fields, to date, autopsy remains the gold standard method to understand the biological features and the pathogenesis of unknown infections, especially when awareness of a pathogen is restricted and the impact on the healthcare system is substantial. The knowledge gained through this technique may positively influence therapeutic strategies, ultimately reducing mortality.

State-of-the-art review of secondary pulmonary infections in patients with COVID-19 pneumonia

Background

The incidence of secondary pulmonary infections is not well described in hospitalized COVID-19 patients. Understanding the incidence of secondary pulmonary infections and the associated bacterial and fungal microorganisms identified can improve patient outcomes.

Objective

This narrative review aims to determine the incidence of secondary bacterial and fungal pulmonary infections in hospitalized COVID-19 patients, and describe the bacterial and fungal microorganisms identified.

Method

We perform a literature search and select articles with confirmed diagnoses of secondary bacterial and fungal pulmonary infections that occur 48 h after admission, using respiratory tract cultures in hospitalized adult COVID-19 patients. We exclude articles involving co-infections defined as infections diagnosed at the time of admission by non-SARS-CoV-2 viruses, bacteria, and fungal microorganisms.

Results

The incidence of secondary pulmonary infections is low at 16% (4.8–42.8%) for bacterial infections and lower for fungal infections at 6.3% (0.9–33.3%) in hospitalized COVID-19 patients. Secondary pulmonary infections are predominantly seen in critically ill hospitalized COVID-19 patients. The most common bacterial microorganisms identified in the respiratory tract cultures are Pseudomonas aeruginosa, Klebsiella species, Staphylococcus aureus, Escherichia coli, and Stenotrophomonas maltophilia. Aspergillus fumigatus is the most common microorganism identified to cause secondary fungal pulmonary infections. Other rare opportunistic infection reported such as PJP is mostly confined to small case series and case reports. The overall time to diagnose secondary bacterial and fungal pulmonary infections is 10 days (2–21 days) from initial hospitalization and 9 days (4–18 days) after ICU admission. The use of antibiotics is high at 60–100% involving the studies included in our review.

Conclusion

The widespread use of empirical antibiotics during the current pandemic may contribute to the development of multidrug-resistant microorganisms, and antimicrobial stewardship programs are required for minimizing and de-escalating antibiotics. Due to the variation in definition across most studies, a large, well-designed study is required to determine the incidence, risk factors, and outcomes of secondary pulmonary infections in hospitalized COVID-19 patients.

On chip optofluidic low-pressure monitoring device

We present an on chip optofluidic surface deformable liquid Dove prism (LDP) based low-fluid flow pressure monitoring device. The unique design of the device in combination with liquid and soft solid enabled by the total internal reflection of light makes the sensor highly sensitive and compatible with the integration of a microfluidic and/or Lab-on-a-chip device. A layer-by-layer soft lithographic (LSL) and 3D printing technique are exploited to make the device. We have used Polydimethylsiloxane (PDMS) as the layer material and two variety of liquids (a) immersion oil (IO) and (b) di-iodomethane (DI) as refracting medium to construct the LDP sensor. Optical ray tracing simulation is performed to optimize the sensor. The pressure sensor shows sensitivity as high as ±28.5 mV per 50 Pa pressure with an error ± 2.5 mV and repeatability of ~99.56% at full scale. We have shown the applicability of the sensor by capturing and analyzing respiratory pressure signals of some human subjects at numerous conditions.

Progression to fibrosing diffuse alveolar damage in a series of 30 minimally invasive autopsies with COVID-19 pneumonia in Wuhan, China

AIMS

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), infection has been deemed as a global pandemic by the World Health Organisation. While diffuse alveolar damage (DAD) is recognised to be the primary manifestation of COVID-19 pneumonia, there has been little emphasis on the progression to the fibrosing phase of DAD. This topic is of great interest, due to growing concerns regarding the potential long-term complications in prolonged survivors.

METHODS AND RESULTS

Here we report a detailed histopathological study of 30 autopsy cases with COVID-19 virus infection, based on minimally invasive autopsies performed between February and March, 2020. The mean age was 69 years, with 20 (67%) males and 10 (33%) females and frequent (70.0%) underlying comorbidities. The duration of illness ranged from 16 to 82 (median = 42) days. Histologically, the most common manifestation was diffuse alveolar damage (DAD) in 28 (93.3%) cases which showed predominantly acute (32%), organising (25%) and/or fibrosing (43%) patterns. Patients with fibrosing DAD were one decade younger (P = 0.034) and they had a longer duration of illness (P = 0.033), hospitalisation (P = 0.037) and mechanical ventilation (P = 0.014) compared to those with acute DAD. Patients with organising DAD had a longer duration of illness (P = 0.032) and hospitalisation (P = 0.023) compared to those with acute DAD.

CONCLUSIONS

COVID-19 pneumonia patients who develop DAD can progress to the fibrosing pattern. While we observed fibrosing DAD in fatal cases, whether or not surviving patients are at risk for developing pulmonary fibrosis and the frequency of this complication will require further clinical and radiological follow-up studies.

The incidence of pleural effusion in COVID-19 pneumonia: State-of-the-art review

BACKGROUND

COVID-19-related pleural effusions are frequently described during the ongoing pandemic.

OBJECTIVES

We described the incidence, characteristics, and outcomes of COVID-19-related pleural effusions based on the current evidence available in the literature.

METHODS

We searched MEDLINE, Pubmed, and Google Scholar databases using keywords of "coronavirus disease 2019 (COVID-19)," "severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)," "pleural effusion," "pleural fluid," and "pleura" from January 1st, 2020 to January 31st, 2021.

RESULTS

The incidence of pleural effusions was low at 7.3% among the 47 observational studies. Pleural effusions were commonly observed in critically ill patients and had Multisystem Inflammatory Syndrome (MIS). COVID-19-related pleural effusions were identified 5-7 days and 11 days, after hospital admission and onset of COVD-19 symptoms. The characteristic findings of pleural fluid were exudative, lymphocytic or neutrophilic-predominant pleural fluid with markedly elevated lactate dehydrogenase (LDH) levels and pleural fluid to serum LDH ratio.

CONCLUSION

A well-designed study is required to assess the significance of COVID-19-related pleural effusions during this current pandemic.

Radiologically Suspected Organizing Pneumonia in a Patient Recovering from COVID-19: A Case Report

We report a case of coronavirus disease 2019 (COVID-19)-associated radiologically suspected organizing pneumonia with repeated negative Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction (PCR) results from nasopharyngeal swab and sputum samples, but positive result from bronchoalveolar lavage fluid. Performing SARS-CoV-2 RT-PCR in upper respiratory tract samples only could fail to detect COVID-19-associated pneumonia, and SARS-CoV-2 could be an etiology of radiologically suspected organizing pneumonia.

Chemokine Regulation During Epidemic Coronavirus Infection

SARS-CoV-2 (Severe Acute Respiratory Syndrome coronavirus-2) is the third coronavirus to emerge as a cause of severe and frequently fatal pneumonia epidemics in humans, joining SARS-CoV and MERS-CoV (Middle East Respiratory Syndrome-coronavirus). As with many infectious diseases, the immune response to coronavirus infection may act as a double-edged sword: necessary for promoting antiviral host defense, but, if not appropriately regulated, also able to incite life-threatening immunopathology. Key immunoregulatory mediators include the chemokines, a large family of leukocyte chemoattractants that coordinate leukocyte infiltration, positioning and activation in infected tissue by acting at specific G protein-coupled receptors. Here, we compare the involvement of chemokines and chemokine receptors during infection with the three epidemic coronaviruses and discuss their potential value as biomarkers and targets for therapeutic development.

SARS-CoV-2 mediated lung inflammatory responses in host: targeting the cytokine storm for therapeutic interventions

The recent exposure of novel coronavirus strain, severe acute respiratory syndrome (SARS-CoV-2) has spread to different countries at an alarming rate. Faster transmission rate and genetic modifications have provoked scientists to search for an immediate solution. With an increasing death rate, it becomes important to throw some light on the life cycle of the virus and its associated pathogenesis in the form of lung inflammation through cytokine storm (CS) production. This paper highlights the different stages of viral-mediated inflammatory responses in the host respiratory system. Previously, known anti-inflammatory drugs and therapeutic strategies that might show potential in controlling the CS of Coronavirus disease-2019 (COVID-19) is also mentioned in this study. Our critical analysis provides insights into the inflammation cycle induced in the lungs by early virus replication, downregulation and shedding of angiotensin-converting enzyme 2 (ACE2), and in the CS production. Identification of suitable targets within the inflammatory pathways for devising the therapeutic strategies useful in controlling the prognosis of COVID-19 finds a special mention in this article. However, antibody-dependent enhancement is the key aspect to consider before testing any drug/compound for therapeutic purposes. Our in-depth analysis would provide similarities and differences between the inflammatory responses induced by SARS-CoV and SARS-CoV-2, providing an excellent avenue to further look at how earlier outbreaks of coronaviruses were controlled and where new steps are required?

Characterizing Viral Infection by Electron Microscopy: Lessons from the Coronavirus Disease 2019 Pandemic

The severe acute respiratory syndrome coronavirus 2 pandemic has infected millions of individuals in the United States and caused hundreds of thousands of deaths. Direct infection of extrapulmonary tissues has been postulated, and using sensitive techniques, viral RNA has been detected in multiple organs in the body, including the kidney. However, direct infection of tissues outside of the lung has been more challenging to demonstrate. This has been in part due to misinterpretation of electron microscopy studies. In this perspective, we will discuss what is known about coronavirus infection, some of the basic ultrastructural cell biology that has been confused for coronavirus infection of cells, and rigorous criteria that should be used when identifying pathogens by electron microscopy.

Research progress and challenges to coronavirus vaccine development

Coronaviruses (CoVs) are nonsegmented, single-stranded, positive-sense RNA viruses highly pathogenic to humans. Some CoVs are known to cause respiratory and intestinal diseases, posing a threat to the global public health. Against this backdrop, it is of critical importance to develop safe and effective vaccines against these CoVs. This review discusses human vaccine candidates in any stage of development and explores the viral characteristics, molecular epidemiology, and immunology associated with CoV vaccine development. At present, there are many obstacles and challenges to vaccine research and development, including the lack of knowledge about virus transmission, pathogenesis, and immune response, absence of the most appropriate animal models.

Chest high-resolution computed tomography is associated to short-time progression to severe disease in patients with COVID-19 pneumonia

OBJECTIVE

In patients with mild COVID-19 pneumonia, chest high-resolution computed tomography (HRCT) is advised when risk factors for severe disease (i.e., age > 65 years and/or comorbidities) are present, and can influence management strategy. The objective was to assess whether HRCT is associated to short-time development of severe disease in patients with COVID-19 pneumonia.

METHODS

Seventy-seven consecutive patients (mean age, 64 ± 15 years) with mild COVID-19 pneumonia (no or mild respiratory failure) that underwent HRCT were retrospectively identified. Fifty-two on 77 patients had reported risk factors for severe disease. A chest-imaging devoted radiologist recorded, on a per-examination basis, the following HRCT features: ground-glass opacity, crazy-paving pattern, consolidation, organizing pneumonia (OP) pattern, mosaic attenuation, and nodules. The extent of each feature (total feature score, TFS) was semi-quantitatively assessed. Total lung involvement (TLI) was defined as the sum of all TFSs. The study outcome was defined as the occurrence of severe disease (moderate-to-severe respiratory failure) within 15 days from HRCT. Logistic regression analysis was performed to assess if age, comorbidities, and HRCT features were associated to severe disease.

RESULTS

On univariable analysis, severe disease was significantly associated with age > 59 years (29/47 patients, 61.7%) (p = 0.013), and not significantly associated with having comorbidities (22/44 patients, 50.0%). On multivariable analysis, TLI >15 and OP pattern >5 were independently associated to severe disease, with odds ratio of 8.380 (p = 0.003), and of 4.685 (p = 0.035), respectively.

CONCLUSION

Short-time onset of severe COVID-19 was associated to TLI >15 and OP pattern score > 5. Severe disease was not associated to comorbidities.

A pilot trial of human amniotic fluid for the treatment of COVID-19

OBJECTIVE

Vertical transmission from SARS CoV-2-infected women is uncommon and coronavirus has not been detected in amniotic fluid. Human amniotic products have a broad immune-mediating profile. Observing that many COVID-19 patients have a profound inflammatory response to the virus, we sought to determine the influence of human amniotic fluid (hAF) on hospitalized patients with COVID-19.

RESULTS

A 10-patient case series was IRB-approved to study the impact of hAF on hospitalized patients with documented COVID-19. Nine of the 10 patients survived to discharge, with one patient succumbing to the disease when enrolled on maximal ventilatory support and severe hypoxia. The study design was altered by the IRB such that the last 6 patients received higher dose of intravenous hAF. In this latter group, patients that had observed reductions in C-reactive protein were associated with improved clinical outcomes. No hAF-related adverse events were noted. Acknowledging some of the inherent limitations of this case series, these results inform and catalyze a larger scaled randomized prospective trial to further investigate hAF as a therapy for COVID-19. Trial Registration ClinicalTrials.gov: NCT04319731; March 23, 2020.