Histopathology of viral infections of the lung

Pathogenicity and virulence of lumpy skin disease virus: A comprehensive update

Lumpy skin disease (LSD), which was confined to the Africa for many decades, has expanded its geographical distribution to numerous countries across Asia and Europe in recent years. The LSD virus (LSDV) is a relatively poorly studied virus. Its 151 Kb genome encodes 156 open reading frames (ORF); however, the exact number of the proteins encoded by the viral genome and their specific functions remain largely unknown. Arthropod vectors primarily transmit the LSDV mechanically, but the precise nature of these vectors in different regions and their role in transmission is not fully understood. Homologous live-attenuated vaccines prepared using LSDV have proven to be highly efficacious compared to heterologous vaccines based on sheep pox virus or goatpox virus, in protecting cattle against LSD. This review offers the latest insights into the molecular biology and transmission of LSDV and discusses the safety and efficacy of available vaccines, along with the challenges faced in controlling and eradicating the disease in endemic regions.

Role of Respiratory Viruses in Severe Acute Respiratory Failure

Respiratory viruses are widespread in the community, affecting both the upper and lower respiratory tract. This review provides an updated synthesis of the epidemiology, pathophysiology, clinical impact, and management of severe respiratory viral infections in critically ill patients, with a focus on immunocompetent adults. The clinical presentation is typically nonspecific, making etiological diagnosis challenging. This limitation has been mitigated by the advent of molecular diagnostics-particularly multiplex PCR (mPCR)-which has not only improved pathogen identification at the bedside but also significantly reshaped our understanding of the epidemiology of respiratory viral infections. Routine mPCR testing has revealed that respiratory viruses are implicated in 30-40% of community-acquired pneumonia hospitalizations and are a frequent trigger of acute decompensations in patients with chronic comorbidities. While some viruses follow seasonal patterns, others circulate year-round. Influenza viruses and Pneumoviridae, including respiratory syncytial virus and human metapneumovirus, remain the principal viral pathogens associated with severe outcomes, particularly acute respiratory failure and mortality. Bacterial co-infections are also common and substantially increase both morbidity and mortality. Despite the growing contribution of respiratory viruses to the burden of critical illness, effective antiviral therapies remain limited. Neuraminidase inhibitors remain the cornerstone of treatment for severe influenza, whereas therapeutic options for other respiratory viruses are largely lacking. Optimizing early diagnosis, refining antiviral strategies, and systematically addressing bacterial co-infections are critical to improving outcomes in patients with severe viral pneumonia.

Pediatric pneumonia - A clinico-pathological study

CONTEXT

Numerous pathogens (bacteria, viruses, or fungi) can cause childhood pneumonia. The clinical presentations of viral and bacterial pneumonia can be similar. Though viruses are a more common cause as compared to bacteria, antibiotics remain the first line of treatment for pneumonia.

AIMS

This study was planned to describe the pulmonary histopathological patterns in cases of pediatric pneumonia (age <12 years) at autopsy and aimed to identify the probable etiology and correlate with clinical presentations.

MATERIALS AND METHODS

This is a single-center 3-year retrospective descriptive autopsy study. Relevant clinical data was correlated with the postmortem findings. The cases were assigned to one of the following categories based on probable etiology: viral, bacterial, mixed, or others.

RESULTS

There were 89 cases with a postmortem diagnosis of pneumonia among 262 autopsied children (34%). Most patients had histological patterns that suggested viral and bacterial etiology in 46 (51.7%) and 27 (30.3%), respectively. A total of 35 out of 46 patients received antibiotics. Twelve cases had mixed viral and bacterial patterns. Antibiotics were also given in the remaining four children (4.5%) with a similar clinical presentation, where a diagnosis of tuberculosis (03 cases) and invasive aspergillosis (01) was made at autopsy.

CONCLUSION

Neither clinical features nor investigations reliably differentiate between viral and bacterial pneumonia. Autopsy has an important role in providing insights into the pathogenesis of pneumonia and suggests inappropriate antibiotic exposure. No prior Indian studies have been performed to compare the clinical and postmortem findings of pneumonia in children.

A 62-Year-Old Woman With Cough, Dyspnea, and Diffuse Lung Nodules

CASE PRESENTATION

A 62-year-old woman came to our hospital with worsening cough and dyspnea over the preceding week, during which time she had been treated with azithromycin and prednisone for suspected pneumonia. She had no fever, chills, or sweats, but her cough had become productive of clear to blood-tinged phlegm during the interval. Medical history was significant for insulin-dependent diabetes mellitus and OSA. She had quit smoking 44 years earlier and had no history of lung disease. She was a bank teller residing in southeastern Minnesota and described no relevant inhalational or environmental exposures, drug use, aspiration, or travels preceding her illness.

Fatal Infections Differentially Involve Allograft and Native Lungs in Single Lung Transplant Recipients

CONTEXT.—

Respiratory infections complicate lung transplantation and increase the risk of allograft dysfunction. Allograft lungs may have different susceptibilities to infection than native lungs, potentially leading to different disease severity in lungs of single lung transplant recipients (SLTRs).

OBJECTIVE.—

To study whether infections affect allograft and native lungs differently in SLTRs but similarly in double LTRs (DLTRs).

DESIGN.—

Using an institutional database of LTRs, medical records were searched, chest computed tomography studies were systematically reviewed, and histopathologic features were recorded per lung lobe and graded semiquantitatively. A multilobar-histopathology score (MLHS) including histopathologic data from each lung and a bilateral ratio (MLHSratio) comparing histopathologies between both lungs were calculated in SLTRs and compared to DLTRs.

RESULTS.—

Six SLTRs died of infection involving the lungs. All allografts showed multifocal histopathologic evidence of infection, but at least 1 lobe of the native lung was uninvolved. In 4 of 5 DLTRs, histopathologic evidence of infection was seen in all lung lobes. On computed tomography, multifocal ground-glass and/or nodular opacities were found in a bilateral distribution in all DLTRs but in only 2 of 6 SLTRs. In SLTRs, the MLHSAllograft was higher than MLHSNative (P = .02). The MLHSratio values of SLTR and DLTR were significantly different (P < .001).

CONCLUSIONS.—

Allograft and native lungs appear to harbor different susceptibilities to infections. The results are important for the management of LTRs.

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.

Virus-Induced Cell Fusion and Syncytia Formation

Most enveloped viruses encode viral fusion proteins to penetrate host cell by membrane fusion. Interestingly, many enveloped viruses can also use viral fusion proteins to induce cell-cell fusion, both in vitro and in vivo, leading to the formation of syncytia or multinucleated giant cells (MGCs). In addition, some non-enveloped viruses encode specialized viral proteins that induce cell-cell fusion to facilitate viral spread. Overall, viruses that can induce cell-cell fusion are nearly ubiquitous in mammals. Virus cell-to-cell spread by inducing cell-cell fusion may overcome entry and post-entry blocks in target cells and allow evasion of neutralizing antibodies. However, molecular mechanisms of virus-induced cell-cell fusion remain largely unknown. Here, I summarize the current understanding of virus-induced cell fusion and syncytia formation.

Lung inflammation is associated with lipid deposition

Lung inflammation, pneumonia, is an acute respiratory disease of varying etiology that has recently drawn much attention during the COVID-19 pandemic as lungs are among the main targets for SARS-CoV-2. Multiple other etiological agents are associated with pneumonias. Here, we describe a newly-recognized pathology, namely abnormal lipid depositions in the lungs of patients who died from COVID-19 as well as from non-COVID-19 pneumonias. Our analysis of both semi-thin and Sudan III-stained lung specimens revealed extracellular and intracellular lipid depositions irrespective of the pneumonia etiology. Most notably, lipid depositions were located within vessels adjacent to inflamed regions, where they apparently interfere with the blood flow. Structurally, the lipid droplets in the inflamed lung tissue were homogeneous and lacked outer membranes as assessed by electron microscopy. Morphometric analysis of lipid droplet deposition area allowed us to distinguish the non-pneumonia control lung specimens from the macroscopically intact area of the pneumonia lung and from the inflamed area of the pneumonia lung. Our measurements revealed a gradient of lipid deposition towards the inflamed region. The pattern of lipid distribution proved universal for all pneumonias. Finally, lipid metabolism in the lung tissue was assessed by the fatty acid analysis and by expression of genes involved in lipid turnover. Chromato-mass spectrometry revealed that unsaturated fatty acid content was elevated at inflammation sites compared to that in control non-inflamed lung tissue from the same individual. The expression of genes involved in lipid metabolism was altered in pneumonia, as shown by qPCR and in silico RNA-seq analysis. Thus, pneumonias of various etiologies are associated with specific lipid abnormalities; therefore, lipid metabolism can be considered to be a target for new therapeutic strategies.

Flurona: The First Autopsied Case

COVID-19-associated coinfections increase the patient's risk of developing a severe form of the disease and, consequently, the risk of death. The term "flurona" was proposed to describe the coinfection of the influenza virus and SARS-CoV-2. This report is about a case of a 7-month-old female infant who died due to flurona coinfection. A histopathological exam showed activation of microglia (becoming CD45 positive), bronchial inflammation, diffuse alveolar damage in proliferative phase with vasculitis, a peribronchial infiltrate that was predominantly CD20-positive, and a vascular wall infiltrate that was predominantly CD3-positive. The aggressiveness of the two respiratory viruses added up and they caused extensive lung inflammation, which led to respiratory failure, multiple organ failure, and death. Tissues injuries caused by both the influenza virus and SARS-CoV-2 could be observed, without the ability to certify the dominance of the aggression of one of the two viruses.

The Stereotypic Response of the Pulmonary Vasculature to Respiratory Viral Infections: Findings in Mouse Models of SARS-CoV-2, Influenza A and Gammaherpesvirus Infections

The respiratory system is the main target of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 19 (COVID-19) where acute respiratory distress syndrome is considered the leading cause of death. Changes in pulmonary blood vessels, among which an endothelialitis/endotheliitis has been particularly emphasized, have been suggested to play a central role in the development of acute lung injury. Similar vascular changes are also observed in animal models of COVID-19. The present study aimed to determine whether the latter are specific for SARS-CoV-2 infection, investigating the vascular response in the lungs of mice infected with SARS-CoV-2 and other respiratory viruses (influenza A and murine gammaherpesvirus) by in situ approaches (histology, immunohistology, morphometry) combined with RNA sequencing and bioinformatic analysis. Non-selective recruitment of monocytes and T and B cells from larger muscular veins and arteries was observed with all viruses, matched by a comparable transcriptional response. There was no evidence of endothelial cell infection in any of the models. Both the morphological investigation and the transcriptomics approach support the interpretation that the lung vasculature in mice mounts a stereotypic response to alveolar and respiratory epithelial damage. This may have implications for the treatment and management of respiratory disease in humans.

Modern approaches at the management of children with community-acquired pneumonia

Experts of The Union of Pediatricians of Russia have developed current clinical guidelines for management of children with community-acquired pneumonia, which were approved by the Scientific and Practice Council of Ministry of Public Health of the Russian Federation in January 2022. Particular attention is paid to the etiological structure, modern classification, diagnostic tests and flagship approaches to antibacterial therapy of community-acquired pneumonia in children based on the principles of evidentiary medicine. 

Engineering organ-on-a-chip systems to model viral infections

Infectious diseases remain a public healthcare concern worldwide. Amidst the pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 infection, increasing resources have been diverted to investigate therapeutics targeting the COVID-19 spike glycoprotein and to develop various classes of vaccines. Most of the current investigations employ two-dimensional (2D) cell culture and animal models. However, 2D culture negates the multicellular interactions and three-dimensional (3D) microenvironment, and animal models cannot mimic human physiology because of interspecies differences. On the other hand, organ-on-a-chip (OoC) devices introduce a game-changer to model viral infections in human tissues, facilitating high-throughput screening of antiviral therapeutics. In this context, this review provides an overview of thein vitroOoC-based modeling of viral infection, highlighting the strengths and challenges for the future.

Biomimetic Neutrophil Nanotoxoids Elicit Potent Immunity against Acinetobacter baumannii in Multiple Models of Infection

Acinetobacter baumannii is a leading cause of antibiotic-resistant nosocomial infections with high mortality rates, yet there is currently no clinically approved vaccine formulation. During the onset of A. baumannii infection, neutrophils are the primary responders and play a major role in resisting the pathogen. Here, we design a biomimetic nanotoxoid for antivirulence vaccination by using neutrophil membrane-coated nanoparticles to safely capture secreted A. baumannii factors. Vaccination with the nanotoxoid formulation rapidly mobilizes innate immune cells and promotes pathogen-specific adaptive immunity. In murine models of pneumonia, septicemia, and superficial wound infection, immunization with the nanovaccine offers significant protection, improving survival and reducing signs of acute inflammation. Lower bacterial burdens are observed in vaccinated animals regardless of the infection route. Altogether, neutrophil nanotoxoids represent an effective platform for eliciting multivalent immunity to protect against multidrug-resistant A. baumannii in a wide range of disease conditions.

Cytopathological Findings in Bronchoalveolar Lavage from Patients with COVID-19

Information on cellular analysis of bronchoalveolar lavage (BAL) in patients with COVID-19 is limited. Some studies have described an increase in lymphocyte percentage or exuberant plasmacytosis. Some reports addressed the importance of molecular testing on BAL samples to confirm COVID-19 pneumonia, in clinically highly suspected patients with consecutive negative nasopharyngeal swab results. In addition to atypical lymphocytes in the peripheral blood, morphologic findings of atypical lymphocytes in BAL were also reported in a few patients. The objective of this study was to describe the cytopathic characteristics identified, any data presented here are descriptives and intended to trigger further research. Three general aspects have been evaluated in each sample: reactive changes, virus-related pathological changes, and differential leukocyte count. Seventeen samples were collected. All samples were negative for malignancy, with an inflammatory background, predominantly lymphohistiocytic in 5 samples, histiocytic in 9, and 3 with predominantly neutrophilic. Hemosiderin-laden macrophages were observed in 12/17. Nonspecific reactive cell changes were identified in 4 samples, including bronchial, alveolar, and reserve cell hyperplasia. Virus-related pathological changes were observed in 14 samples, such as loss of nuclear chromatin pattern, lymphocytes with atypical nuclei, nuclear and cytoplasmic inclusions, multinucleations in bronchial cells and macrophages, or multinucleated giant cells. The identification of multinucleated giant cells could represent a cytopathic effect induced by the virus, at the same time the nuclear clearance of pneumocytes as a possible direct effect. BAL is a procedure aimed at obtaining cells from the respiratory tract that can provide valuable and rapid information. It is important to collect and describe as many cytopathological findings as possible, which can provide relevant information for future studies.

Title-Inflammatory Signaling Pathways in Allergic and Infection-Associated Lung Diseases

Lung inflammation can be caused by pathogen infection alone or by allergic disease, leading to pneumonitis. Most of the allergens (antigens) that cause allergic lung diseases, including asthma and hypersensitivity pneumonitis (HP), are derived from microorganisms, such as bacteria, viruses, and fungi, but some inorganic materials, such as mercury, can also cause pneumonitis. Certain allergens, including food and pollen, can also cause acute allergic reactions and lead to lung inflammation in individuals predisposed to such reactions. Pattern recognition-associated and damage-associated signaling by these allergens can be critical in determining the type of hypersensitization and allergic disease, as well as the potential for fibrosis and irreversible lung damage. This review discusses the signs, symptoms, and etiology of allergic asthma, and HP. Furthermore, we review the immune response and signaling pathways involved in pneumonitis due to both microbial infection and allergic processes. We also discuss current and potential therapeutic interventions for infection-associated and allergic lung inflammation.

Molecular detection and genetic characterization of human metapneumovirus strains circulating in Islamabad, Pakistan

Lower respiratory illness is one of the leading causes of death among children in low- and high-income countries. Human metapneumovirus (hMPV) is a key contributor to respiratory illnesses commonly reported among children and causes serious clinical complications ranging from mild respiratory infections to severe lower respiratory tract anomalies mainly in the form of bronchiolitis and pneumonia. However, due to the lack of a national surveillance system, the clinical significance of hMPV remains obscure in the Pakistani population. This study was conducted to screen throat swabs samples collected from 127 children reported with respiratory symptoms at a tertiary care hospital in Islamabad. Out of 127, 21 (16.5%) samples were positive for hMPV with its genotype distribution as A2a (10%), A2b (20%), B1 (10%), and B2 (60%). Phylogenetic analysis showed that the hMPV viruses were closely related to those reported from neighboring countries including India and China. This work will contribute to a better understanding of this virus, its diagnosis, and the handling of patients in clinical setups. Further studies at a large-scale are warranted for a better understanding of the disease burden and epidemiology of hMPV in Pakistan.

COVID-19 versus H1N1: challenges in radiological diagnosis—comparative study on 130 patients using chest HRCT

Background

During the current second wave of COVID-19, the radiologists are expected to face great challenges in differentiation between COVID-19 and other virulent influenza viruses, mainly H1N1. Accordingly, this study was performed in order to find any differentiating CT criteria that would help during the expected clinical overlap during the current Influenza season.

Results

This study was retrospectively conducted during the period from June till November 2020, on acute symptomatic 130 patients with no history of previous pulmonary diseases; 65 patients had positive PCR for COVID-19 including 50 mild patients and 15 critical or severe patients; meanwhile, the other 65 patients had positive PCR for H1N1 including 50 mild patients and 15 critical or severe patients. They included 74 males and 56 females (56.9%:43.1%). Their age ranged 14–90 years (mean age 38.9 ± 20.3 SD). HRCT findings were analyzed by four expert consultant radiologists in consensus. All patients with COVID-19 showed parenchymal or alveolar HRCT findings; only one of them had associated airway involvement. Among the 65 patients with H1N1; 56 patients (86.2%) had parenchymal or alveolar HRCT findings while six patients (9.2%) presented only by HRCT signs of airway involvement and three patients (4.6%) had mixed parenchymal and airway involvement. Regarding HRCT findings of airway involvement (namely tree in bud nodules, air trapping, bronchial wall thickening, traction bronchiectasis, and mucous plugging), all showed significant p value (ranging from 0.008 to 0.04). On the other hand, HRCT findings of parenchymal or alveolar involvement (mainly ground glass opacities) showed no significant relation.

Conclusion

HRCT can help in differentiation between non-severe COVID-19 and H1N1 based on signs of airway involvement.

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.

Rag2 Deficiency Enhances Susceptibility to Systemic Mouse Adenovirus Type 1 Infection

Introduction

Recombination-activating gene (Rag) 1 and Rag2, which are essential in V(D)J recombination, play a crucial role in B- and T-cell maturation.

Method

We investigated the effects of Rag2 deficiency in clustered regularly interspaced short palindromic repeats/Cas9-mediated FVB-Rag2 knockout (KO) and wild-type (WT) mice infected with mouse adenovirus type 1 (MAV-1) via the intranasal route.

Results

MAV-1 infection caused more severe histopathological changes in FVB-Rag2 KO mice than in WT mice. FVB-Rag2 KO mice exhibited moderate to severe inflammation on day 4 and severe inflammation on day 8 post infection. In contrast, WT mice showed mild inflammation on day 4 and mild to severe inflammation on day 8 post infection, including interstitial pneumonia and inflammatory cell infiltration in the lungs and liver. Viral loads in the spleen and kidneys were significantly higher in FVB-Rag2 KO mice than in WT mice on day 8 post infection. Levels of cytokines and chemokines, including macrophage inflammatory protein-1α, induced protein 10, interferon (IFN)-α, IFN-γ, and tumor necrosis factor alpha, were upregulated in the spleens of FVB-Rag2 KO mice compared with those of WT mice. The upregulation of several cytokines occurred concurrently with the histopathological changes. MAV-1 infection induced more severe systemic infection in FVB-Rag2 KO mice than in WT mice.

Conclusion

In mice, Rag2 deficiency induces inflammatory cell recruitment via the upregulation of cytokine and chemokine levels. The MAV-1 infection model can be utilized to assess the efficacy and safety of therapeutic agents for human adenoviral diseases.

Network-based pharmacology to predict the mechanism of Ginger and Forsythia combined treatment of viral pneumonia

BACKGROUND

Viral pneumonia (VP) is a common inflammatory disease caused by a virus in the upper respiratory tract. However, current treatment options for pneumonia are limited because of the strong infectivity and lack of research.

METHOD

Based on various databases, the mechanisms of Ginger and Forsythia were predicted by network pharmacology. The possible active ingredients of Ginger and Forsythia were obtained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and screened by pharmacokinetic parameters. Their possible targets were predicted by the TCMSP database. The VP-related targets were collected from the GeneCards and OMIM databases. The compound-target-disease network was visualized by Cytoscape 3.7.1. In addition, the protein functional annotation and identification of signalling pathways of possible targets were performed with Gene Ontology (GO) and KEGG enrichment analysis. Molecular docking was finally employed for in silico simulation matching between representative Ginger and Forsythia compounds and their core genes.

RESULTS

Twenty-eight active ingredients of Ginger and Forsythia were found and 30 common targets for the combined treatment of VP were obtained. The enrichment analysis of GO functions and KEGG pathways included 186 GO function entries and 56 KEGG pathways. Molecular docking showed that the main ingredients can closely bind three targets (CASP3, JUN, and ESR1). Thus, Ginger and Forsythia play significant roles in the prevention and treatment of VP, and this study showed their mechanism was "multicomponent, multitarget, and multipathway" for the prevention and treatment of VP.

CONCLUSION

We successfully predicted the active components and targets of Ginger and Forsythia for prevention and treatment of VP. This may systematically clarify its mechanism of action and provide a direction for future research.

Respiratory Nasal Mucosa in Chronic Rhinosinusitis with Nasal Polyps versus COVID-19: Histopathology, Electron Microscopy Analysis and Assessing of Tissue Interleukin-33

(1) Background: Chronic rhinosinusitis with nasal polyps (CRSwNP) is one of the most studied rhinological disorders. Modifications of the respiratory nasal mucosa in COVID-19 patients are so far unknown. This paper presents a comparative morphological characterization of the respiratory nasal mucosa in CRSwNP versus COVID-19 and tissue interleukin (IL)-33 concentration. (2) Methods: We analyzed CRSwNP and COVID-19 samples through histopathology, scanning and transmission electron microscopy and performed proteomic determination of IL-33. (3) Results: Histopathologically, stromal edema (p < 0.0001) and basal membrane thickening (p = 0.0768) were found more frequently in CRSwNP than in COVID-19. Inflammatory infiltrate was mainly eosinophil-dominant in CRSwNP and lymphocyte-dominant in COVID-19 (p = 0.3666). A viral cytopathic effect was identified in COVID-19. Scanning electron microscopy detected biofilms only in CRSwNP, while most COVID-19 samples showed microbial aggregates (p = 0.0148) and immune cells (p = 0.1452). Transmission electron microscopy of CRSwNP samples identified biofilms, mucous cell hyperplasia (p = 0.0011), eosinophils, fibrocytes, mastocytes, and collagen fibers. Extracellular suggestive structures for SARS-CoV-2 and multiple Golgi apparatus in epithelial cells were detected in COVID-19 samples. The tissue IL-33 concentration in CRSwNP (210.0 pg/7 μg total protein) was higher than in COVID-19 (52.77 pg/7 μg total protein) (p < 0.0001), also suggesting a different inflammatory pattern. (4) Conclusions: The inflammatory pattern is different in each of these disorders. Results suggested the presence of nasal dysbiosis in both conditions, which could be a determining factor in CRSwNP and a secondary factor in COVID-19.

Organizing pneumonia associated with SARS-CoV-2 infection

Organizing pneumonia is a nonspecific pulmonary response pattern associated with a variety of clinical contexts including viral infections. The classic radiological manifestations are peribronchovascular/peripheral ground glass opacities or consolidations and may be accompanied by nodules, masses, and interstitial opacities. We describe the case of a 62-year-old male patient with SARS-CoV-2 pneumonia and torpid clinical and radiological evolution in whom organizing pneumonia was documented through transbronchial biopsy and imaging findings, with a good response to corticosteroids. The importance of recognizing the development of organizing pneumonia lies in the better prognosis and outcome in those patients who receive treatment with corticosteroids, however, the clinical and radiological suspicion must be confirmed with biopsy because radiological findings associated with bacterial coinfection may overlap.

Histopathological findings and clinicopathologic correlation in COVID-19: a systematic review

The severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) pandemic has had devastating effects on global health and worldwide economy. Despite an initial reluctance to perform autopsies due to concerns for aerosolization of viral particles, a large number of autopsy studies published since May 2020 have shed light on the pathophysiology of Coronavirus disease 2019 (COVID-19). This review summarizes the histopathologic findings and clinicopathologic correlations from autopsies and biopsies performed in patients with COVID-19. PubMed and Medline (EBSCO and Ovid) were queried from June 4, 2020 to September 30, 2020 and histopathologic data from autopsy and biopsy studies were collected based on 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 58 studies reporting 662 patients were included. Demographic data, comorbidities at presentation, histopathologic findings, and virus detection strategies by organ system were collected. Diffuse alveolar damage, thromboembolism, and nonspecific shock injury in multiple organs were the main findings in this review. The pathologic findings emerging from autopsy and biopsy studies reviewed herein suggest that in addition to a direct viral effect in some organs, a unifying pathogenic mechanism for COVID-19 is ARDS with its known and characteristic inflammatory response, cytokine release, fever, inflammation, and generalized endothelial disturbance. This study supports the notion that autopsy studies are of utmost importance to our understanding of disease features and treatment effect to increase our knowledge of COVID-19 pathophysiology and contribute to more effective treatment strategies.

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.

Pneumonia

Pneumonia is a common acute respiratory infection that affects the alveoli and distal airways; it is a major health problem and associated with high morbidity and short-term and long-term mortality in all age groups worldwide. Pneumonia is broadly divided into community-acquired pneumonia or hospital-acquired pneumonia. A large variety of microorganisms can cause pneumonia, including bacteria, respiratory viruses and fungi, and there are great geographical variations in their prevalence. Pneumonia occurs more commonly in susceptible individuals, including children of <5 years of age and older adults with prior chronic conditions. Development of the disease largely depends on the host immune response, with pathogen characteristics having a less prominent role. Individuals with pneumonia often present with respiratory and systemic symptoms, and diagnosis is based on both clinical presentation and radiological findings. It is crucial to identify the causative pathogens, as delayed and inadequate antimicrobial therapy can lead to poor outcomes. New antibiotic and non-antibiotic therapies, in addition to rapid and accurate diagnostic tests that can detect pathogens and antibiotic resistance will improve the management of pneumonia.

Virus-Mediated Cell-Cell Fusion

Cell-cell fusion between eukaryotic cells is a general process involved in many physiological and pathological conditions, including infections by bacteria, parasites, and viruses. As obligate intracellular pathogens, viruses use intracellular machineries and pathways for efficient replication in their host target cells. Interestingly, certain viruses, and, more especially, enveloped viruses belonging to different viral families and including human pathogens, can mediate cell-cell fusion between infected cells and neighboring non-infected cells. Depending of the cellular environment and tissue organization, this virus-mediated cell-cell fusion leads to the merge of membrane and cytoplasm contents and formation of multinucleated cells, also called syncytia, that can express high amount of viral antigens in tissues and organs of infected hosts. This ability of some viruses to trigger cell-cell fusion between infected cells as virus-donor cells and surrounding non-infected target cells is mainly related to virus-encoded fusion proteins, known as viral fusogens displaying high fusogenic properties, and expressed at the cell surface of the virus-donor cells. Virus-induced cell-cell fusion is then mediated by interactions of these viral fusion proteins with surface molecules or receptors involved in virus entry and expressed on neighboring non-infected cells. Thus, the goal of this review is to give an overview of the different animal virus families, with a more special focus on human pathogens, that can trigger cell-cell fusion.

Calcineurin phosphatase activity regulates Varicella-Zoster Virus induced cell-cell fusion

Cell-cell fusion (abbreviated as cell fusion) is a characteristic pathology of medically important viruses, including varicella-zoster virus (VZV), the causative agent of chickenpox and shingles. Cell fusion is mediated by a complex of VZV glycoproteins, gB and gH-gL, and must be tightly regulated to enable skin pathogenesis based on studies with gB and gH hyperfusogenic VZV mutants. Although the function of gB and gH-gL in the regulation of cell fusion has been explored, whether host factors are directly involved in this regulation process is unknown. Here, we discovered host factors that modulated VZV gB/gH-gL mediated cell fusion via high-throughput screening of bioactive compounds with known cellular targets. Two structurally related non-antibiotic macrolides, tacrolimus and pimecrolimus, both significantly increased VZV gB/gH-gL mediated cell fusion. These compounds form a drug-protein complex with FKBP1A, which binds to calcineurin and specifically inhibits calcineurin phosphatase activity. Inhibition of calcineurin phosphatase activity also enhanced both herpes simplex virus-1 fusion complex and syncytin-1 mediated cell fusion, indicating a broad role of calcineurin in modulating this process. To characterize the role of calcineurin phosphatase activity in VZV gB/gH-gL mediated fusion, a series of biochemical, biological and infectivity assays was performed. Pimecrolimus-induced, enhanced cell fusion was significantly reduced by shRNA knockdown of FKBP1A, further supporting the role of calcineurin phosphatase activity in fusion regulation. Importantly, inhibition of calcineurin phosphatase activity during VZV infection caused exaggerated syncytia formation and suppressed virus propagation, which was consistent with the previously reported phenotypes of gB and gH hyperfusogenic VZV mutants. Seven host cell proteins that remained uniquely phosphorylated when calcineurin phosphatase activity was inhibited were identified as potential downstream factors involved in fusion regulation. These findings demonstrate that calcineurin is a critical host cell factor pivotal in the regulation of VZV induced cell fusion, which is essential for VZV pathogenesis.

A model of respiratory syncytial virus (RSV) infection of infants in newborn lambs

Many animal models have been established for respiratory syncytial virus (RSV) infection of infants with the purpose of studying the pathogenesis, immunological response, and pharmaceutical testing and the objective of finding novel therapies and preventive measures. This review centers on a neonatal lamb model of RSV infection that has similarities to RSV infection of infants. It includes a comprehensive description of anatomical and immunological similarities between ovine and human lungs along with comparison of pulmonary changes and immune responses with RSV infection. These features make the newborn lamb an effective model for investigating key aspects of RSV infection in infants. The importance of RSV lamb model application in preclinical therapeutic trials and current updates on new studies with the RSV-infected neonatal lamb are also highlighted.