"A Chain Only as Strong as Its Weakest Link": An Up-to-Date Literature Review on the Bidirectional Interaction of Pulmonary Fibrosis and COVID-19

Influenza, SARS-CoV-2, and Their Impact on Chronic Lung Diseases and Fibrosis: Exploring Therapeutic Options

Respiratory tract infections represent a significant global public health concern, disproportionately affecting vulnerable populations such as children, the elderly, and immunocompromised individuals. RNA viruses, particularly influenza viruses and coronaviruses, significantly contribute to respiratory illnesses, especially in immunosuppressed and elderly individuals. Influenza A viruses (IAVs) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continue to pose global health threats due to their capacity to cause annual epidemics, with profound implications for public health. In addition, the increase in global life expectancy is influencing the dynamics and outcomes of respiratory viral infections. Understanding the molecular mechanisms by which IAVs and SARS-CoV-2 contribute to lung disease progression is therefore crucial. The aim of this review was to comprehensively explore the impact of IAVs and SARS-CoV-2 on chronic lung diseases, with a specific focus on pulmonary fibrosis in the elderly. It also outlines potential preventive and therapeutic strategies and suggests directions for future research.

The CXCL9/10/11-CXCR3 axis as a predictor of COVID-19 progression: a prospective, case-control study

BACKGROUND

This study examined the relationship between levels of the chemokines CXCL9, CXCL10, CXCL11, and CXCR3 and mortality in patients with COVID-19..

METHODS

A total of 71 patients hospitalized with COVID-19 and 35 health workers with no symptoms and negative SARS-CoV-2 PCR results were included in the study. CXCL9, CXCL10, CXCL11, and CXCR3 levels were measured in blood samples using enzyme-linked immunosorbent assays. Participants were divided into three groups: healthy individuals, patients with mild to moderate pneumonia, and patients with severe pneumonia. Patients were also divided into sub-groups according to the outcome: dead and survived.

RESULTS

Serum CXCL9, CXCL10, CXCL11, and CXCR3 levels were significantly higher in patients with severe COVID-19 than in those with non-severe COVID-19; were higher in both patient groups than in the control group; and were higher in patients who died than in those who survived. Lymphocyte counts, and fibrinogen and PaO2/FiO2 levels were significantly lower in patients with severe COVID-19 than in those with moderate disease. Patients with COVID-19 also had elevated neutrophil/lymphocyte ratios, neutrophil counts, and lactate dehydrogenase, C-reactive protein, D-dimer, and ferritin levels.

CONCLUSIONS

This study confirmed that CXCL9, CXCL10, CXCL11, and CXCR3 levels are associated with disease severity in patients with COVID-19. These laboratory parameters can help to estimate disease severity and predict outcomes, and are useful in clinical decision-making.

Pulmonary fibrosis: A short- or long-term sequelae of severe COVID-19?

The pandemic of coronavirus disease 2019 (COVID‑19), caused by a novel severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2), has caused an enormous impact on the global healthcare. SARS-CoV-2 infection primarily targets the respiratory system. Although most individuals testing positive for SARS-CoV-2 present mild or no upper respiratory tract symptoms, patients with severe COVID-19 can rapidly progress to acute respiratory distress syndrome (ARDS). ARDS-related pulmonary fibrosis is a recognized sequelae of COVID-19. Whether post-COVID-19 lung fibrosis is resolvable, persistent, or even becomes progressive as seen in human idiopathic pulmonary fibrosis (IPF) is currently not known and remains a matter of debate. With the emergence of effective vaccines and treatments against COVID-19, it is now important to build our understanding of the long-term sequela of SARS-CoV-2 infection, to identify COVID-19 survivors who are at risk of developing chronic pulmonary fibrosis, and to develop effective anti-fibrotic therapies. The current review aims to summarize the pathogenesis of COVID-19 in the respiratory system and highlights ARDS-related lung fibrosis in severe COVID-19 and the potential mechanisms. It envisions the long-term fibrotic lung complication in COVID-19 survivors, in particular in the aged population. The early identification of patients at risk of developing chronic lung fibrosis and the development of anti-fibrotic therapies are discussed.

COVID-19 and protection of vaccination in patients with systemic sclerosis-associated interstitial lung disease

OBJECTIVES

Data on COVID-19 in patients with interstitial lung disease are scarce and whether SARS-CoV-2 may trigger interstitial lung disease progression remains unknown. We aimed to analyze outcomes of COVID-19 in patients with systemic sclerosis-associated interstitial lung disease, including possible thoracic radiographic progression.

PATIENTS AND METHODS

All 43 patients with systemic sclerosis-associated interstitial lung disease followed in our center (mean ± SD, 55.2 ± 11.6 years, 36 female) with confirmed SARS-CoV2 infection up to 1 September 2022 were analyzed. Individual interstitial lung disease extent on high resolution CT (HRCT) performed before (up to 3 months) and after COVID-19 (2-5 months) was compared.

RESULTS

At SARS-CoV-2 infection, 9/43 patients were unvaccinated, whereas 5, 26, and 3 had received 2, 3, or 4 doses of an mRNA vaccine, respectively. Thirty-one patients were either on monotherapy with immunosuppressives (mycophenolate, n = 7; cyclophosphamide, n = 2; methotrexate, n = 10; tocilizumab, n = 7; rituximab, n = 1; etanercept, n = 1), or their combinations (n = 3). Eight patients (20%), of whom four unvaccinated, required hospitalization for pneumonia and three (7%) died of acute respiratory failure (n = 2, both unvaccinated) or cardiac arrest. Lack of vaccination was the only independent predictor for hospitalization (OR = 7.98, 95% CI: 1.25-51.09) and marginally for death (OR = 32.7, 95% CI: 0.97-1110.98), regardless of the presence of diffuse systemic sclerosis, interstitial lung disease extent greater than 20% or immunosuppressive treatment. In 22 patients with available HRCT pairs (vaccinated = 20), the interstitial lung disease extent before COVID-19 (20.4%± 17.8%) remained unchanged (22.4% ± 18.5%) in all but one patient.

CONCLUSION

SARS-CoV-2 vaccination is of outmost importance for every systemic sclerosis patient with interstitial lung disease. COVID-19 does not seem to promote progression of systemic sclerosis-associated interstitial lung disease in vaccinated patients, but further studies are warranted.

Severe COVID-19 pneumonia leads to post-COVID-19 lung abnormalities on follow-up CT scans

Purpose

To investigate the association of the maximal severity of pneumonia on CT scans obtained within 6-week of diagnosis with the subsequent development of post-COVID-19 lung abnormalities (Co-LA).

Methods

COVID-19 patients diagnosed at our hospital between March 2020 and September 2021 were studied retrospectively. The patients were included if they had (1) at least one chest CT scan available within 6-week of diagnosis; and (2) at least one follow-up chest CT scan available ≥ 6 months after diagnosis, which were evaluated by two independent radiologists. Pneumonia Severity Categories were assigned on CT at diagnosis according to the CT patterns of pneumonia and extent as: 1) no pneumonia (Estimated Extent, 0%); 2) non-extensive pneumonia (GGO and OP, <40%); and 3) extensive pneumonia (extensive OP and DAD, >40%). Co-LA on follow-up CT scans, categorized using a 3-point Co-LA Score (0, No Co-LA; 1, Indeterminate Co-LA; and 2, Co-LA).

Results

Out of 132 patients, 42 patients (32%) developed Co-LA on their follow-up CT scans 6-24 months post diagnosis. The severity of COVID-19 pneumonia was associated with Co-LA: In 47 patients with extensive pneumonia, 33 patients (70%) developed Co-LA, of whom 18 (55%) developed fibrotic Co-LA. In 52 with non-extensive pneumonia, 9 (17%) developed Co-LA: In 33 with no pneumonia, none (0%) developed Co-LA.

Conclusions

Higher severity of pneumonia at diagnosis was associated with the increased risk of development of Co-LA after 6-24 months of SARS-CoV-2 infection.

Pulmonary Fibrosis as a Result of Acute Lung Inflammation: Molecular Mechanisms, Relevant In Vivo Models, Prognostic and Therapeutic Approaches

Pulmonary fibrosis is a chronic progressive lung disease that steadily leads to lung architecture disruption and respiratory failure. The development of pulmonary fibrosis is mostly the result of previous acute lung inflammation, caused by a wide variety of etiological factors, not resolved over time and causing the deposition of fibrotic tissue in the lungs. Despite a long history of study and good coverage of the problem in the scientific literature, the effective therapeutic approaches for pulmonary fibrosis treatment are currently lacking. Thus, the study of the molecular mechanisms underlying the transition from acute lung inflammation to pulmonary fibrosis, and the search for new molecular markers and promising therapeutic targets to prevent pulmonary fibrosis development, remain highly relevant tasks. This review focuses on the etiology, pathogenesis, morphological characteristics and outcomes of acute lung inflammation as a precursor of pulmonary fibrosis; the pathomorphological changes in the lungs during fibrosis development; the known molecular mechanisms and key players of the signaling pathways mediating acute lung inflammation and pulmonary fibrosis, as well as the characteristics of the most common in vivo models of these processes. Moreover, the prognostic markers of acute lung injury severity and pulmonary fibrosis development as well as approved and potential therapeutic approaches suppressing the transition from acute lung inflammation to fibrosis are discussed.

Possible Role of Matrix Metalloproteinases and TGF-β in COVID-19 Severity and Sequelae

The costs of coronavirus disease 2019 (COVID-19) are devastating. With millions of deaths worldwide, specific serological biomarkers, antiviral agents, and novel therapies are urgently required to reduce the disease burden. For these purposes, a profound understanding of the pathobiology of COVID-19 is mandatory. Notably, the study of immunity against other respiratory infections has generated reference knowledge to comprehend the paradox of the COVID-19 pathogenesis. Past studies point to a complex interplay between cytokines and other factors mediating wound healing and extracellular matrix (ECM) remodeling that results in exacerbated inflammation, tissue injury, severe manifestations, and a sequela of respiratory infections. This review provides an overview of the immunological process elicited after severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Also, we analyzed available data about the participation of matrix metalloproteinases (MMPs) and transforming growth factor-beta (TGF-β) in immune responses of the lungs. Furthermore, we discuss their possible implications in severe COVID-19 and sequela, including pulmonary fibrosis, and remark on the potential of these molecules as biomarkers for diagnosis, prognosis, and treatment of convalescent COVID-19 patients. Our review provides a theoretical framework for future research aimed to discover molecular hallmarks that, combined with clinical features, could serve as therapeutic targets and reliable biomarkers of the different clinical forms of COVID-19, including convalescence.

A Silent March- Post Covid Fibrosis in Asymptomatics-A Cause for Concern?

We report a case series of patients presenting with undiagnosed pulmonary fibrosis as a primary manifestation. On evaluation, after excluding other causes, the fibrosis was attributed to asymptomatic or mild COVID illness in the past. This case series serves to highlight the difficulties posed to clinicians while evaluating pulmonary fibrosis in the post-COVID era, more so in mild to asymptomatic COVID-19. The intriguing possibility of fibrosis setting even in mild to asymptomatic COVID is discussed.

Research on the mechanism of berberine in the treatment of COVID-19 pneumonia pulmonary fibrosis using network pharmacology and molecular docking

Purpose Pulmonary fibrosis caused by COVID-19 pneumonia is a serious complication of COVID-19 infection, there is a lack of effective treatment methods clinically. This article explored the mechanism of action of berberine in the treatment of COVID-19 (Corona Virus Disease 2019, COVID-19) pneumonia pulmonary fibrosis with the help of the network pharmacology and molecular docking. Methods We predicted the role of berberine protein targets with the Pharmmapper database and the 3D structure of berberine in the Pubchem database. And GeneCards database was used in order to search disease target genes and screen common target genes. Then we used STRING web to construct PPI interaction network of common target protein. The common target genes were analyzed by GO and KEGG by DAVID database. The disease-core target gene-drug network was established and molecular docking was used for prediction. We also analyzed the binding free energy and simulates molecular dynamics of complexes. Results Berberine had 250 gene targets, COVID-19 pneumonia pulmonary fibrosis had 191 gene targets, the intersection of which was 23 in common gene targets. Molecular docking showed that berberine was associated with CCl2, IL-6, STAT3 and TNF-α. GO and KEGG analysis reveals that berberine mainly plays a vital role by the signaling pathways of influenza, inflammation and immune response. Conclusion Berberine acts on TNF-α, STAT3, IL-6, CCL2 and other targets to inhibit inflammation and the activation of fibrocytes to achieve the purpose of treating COVID-19 pneumonia pulmonary fibrosis.

Optimal intervention strategies to mitigate the COVID-19 pandemic effects

Governments across the world are currently facing the task of selecting suitable intervention strategies to cope with the effects of the COVID-19 pandemic. This is a highly challenging task, since harsh measures may result in economic collapse while a relaxed strategy might lead to a high death toll. Motivated by this, we consider the problem of forming intervention strategies to mitigate the impact of the COVID-19 pandemic that optimize the trade-off between the number of deceases and the socio-economic costs. We demonstrate that the healthcare capacity and the testing rate highly affect the optimal intervention strategies. Moreover, we propose an approach that enables practical strategies, with a small number of policies and policy changes, that are close to optimal. In particular, we provide tools to decide which policies should be implemented and when should a government change to a different policy. Finally, we consider how the presented results are affected by uncertainty in the initial reproduction number and infection fatality rate and demonstrate that parametric uncertainty has a more substantial effect when stricter strategies are adopted.

Inhalable cryptotanshinone spray-dried swellable microparticles for pulmonary fibrosis therapy by regulating TGF-β1/Smad3, STAT3 and SIRT3 pathways

Cryptotanshinone (CTS) is a promising therapeutic option for pulmonary fibrosis (PF). However, clinical applications of CTS are limited owing to high photosensitivity and poor oral bioavailability. Pulmonary drug delivery, especially sustained pulmonary drug delivery, is promising for local treatment of chronic lung diseases. In this study, CTS was encapsulated in an optimized chitosan/L-leucine-based swellable microparticles (SMs) system, which exhibited an appropriate aerosolization performance, sustained release and storage stability. SMs enhanced the in vitro anti-fibrosis efficacy of CTS as shown by the improved cellular uptake. The effect of PF status on in vivo fate of the pulmonary delivered drug was also assessed. Pharmacokinetics and tissue distribution of oral and pulmonary delivery CTS in bleomycin-induced PF rats were compared. Pulmonary delivery exhibited high drug concentrations in pulmonary lesion areas, with reduced exposure to blood and non-targeted tissues after administration at a significantly lower dose compared with oral delivery. Moreover, PF pathological status enhanced activity of SMs, implying that pulmonary delivery was highly effective for PF treatment. Compared to oral delivery, Inhaled SMs showed comparable or even better efficacies at approximately 60-fold low dose compared with oral delivery. A sustained efficacy was observed under a prolonged administration interval (corresponding to half the total dose). Inhalation safety of SMs was established, and important mechanism-related signaling pathways against PF were investigated in vitro and in vivo. In summary, the findings showed that the developed CTS-loaded sustained pulmonary delivery system is a safe and effective strategy for chronic PF treatment.

The Interaction Between Pulmonary Fibrosis and COVID-19 and the Application of Related Anti-Fibrotic Drugs

COVID-19 is a highly contagious respiratory disease, which mainly affects the lungs. Critically ill patients are easily complicated by cytokine storms, acute respiratory distress syndrome (ARDS), and respiratory failure, which seriously threaten their lives. Pulmonary fibrosis (PF) is a common interstitial lung disease, and its pathogenesis may involve the participation of a variety of immune cells and inflammatory factors. Current studies have shown that patients with COVID-19 may be complicated by pulmonary fibrosis, and patients with pulmonary fibrosis may also be at higher risk of contracting COVID-19 than healthy people. Pulmonary fibrosis is an important risk factor leading to the aggravation of COVID-19 disease. COVID-19 complicated by cytokine storm and ARDS mechanism pathways are similar to the pathogenesis of pulmonary fibrosis. The potential interaction between pulmonary fibrosis and COVID-19 can cause acute exacerbation of the patient’s condition, but the potential mechanism between the two has not been fully elucidated. Most of the drug treatment programs for COVID-19-related pulmonary fibrosis are currently formulated about the relevant guidelines for idiopathic pulmonary fibrosis (IPF), and there is no clear drug treatment program recommendation. This article aims to summarize the relevant mechanism pathways of COVID-19 and pulmonary fibrosis, explore the interrelationships and possible mechanisms, and discuss the value and risks of existing and potential COVID-19-related pulmonary fibrosis treatment drugs, to provide reference for anti-fibrosis treatment for patients.

Virus infection induced pulmonary fibrosis

Pulmonary fibrosis is the end stage of a broad range of heterogeneous interstitial lung diseases and more than 200 factors contribute to it. In recent years, the relationship between virus infection and pulmonary fibrosis is getting more and more attention, especially after the outbreak of SARS-CoV-2 in 2019, however, the mechanisms underlying the virus-induced pulmonary fibrosis are not fully understood. Here, we review the relationship between pulmonary fibrosis and several viruses such as Human T-cell leukemia virus (HTLV), Human immunodeficiency virus (HIV), Cytomegalovirus (CMV), Epstein–Barr virus (EBV), Murine γ-herpesvirus 68 (MHV-68), Influenza virus, Avian influenza virus, Middle East Respiratory Syndrome (MERS)-CoV, Severe acute respiratory syndrome (SARS)-CoV and SARS-CoV-2 as well as the mechanisms underlying the virus infection induced pulmonary fibrosis. This may shed new light on the potential targets for anti-fibrotic therapy to treat pulmonary fibrosis induced by viruses including SARS-CoV-2.

Corticosteroids in SARS-COV2 infection: certainties and uncertainties in clinical practice

INTRODUCTION

The SARS-COV-2 pandemic is a worldwide public health problem due to the large medical burden and limited number of therapies available. Corticosteroids have a rather unclear efficacy in viral non-SARS-COV-2 pneumonias and therefore their use is not universally recommended. In SARS-COV-2 pneumonia however, it is expected that they can reduce the deleterious consequences of the virus-related systemic inflammation.

AREAS COVERED

a MEDLINE search covering the period 1995-2020 was completed to identify relevant papers. SARS-COV-2 pathogenesis is very complex and is represented by the interplay of many cytokine-driven inflammation pathways. Its most severe form so called cytokine storm, is an exaggerate reaction of the host infected by the virus rapidly resulting in multiple organ dysfunction (MODS). Corticosteroids have the potential to blunt the inflammation response in such patients, but their efficacy is not the same for all patients. Further on the certainties and uncertainties regarding the efficacy of this therapy in SARS-COV-2 pneumonia are discussed.

EXPERT OPINION

In patients with severe SARS-COV-2 pneumonia, corticosteroids can be efficacious, but it is still not clear if they can be safely used in patients with comorbid cardiovascular disease or how the optimal duration of therapy can be established.

A metabolomic approach to elucidate the inhibitory effects of baicalin in pulmonary fibrosis

CONTEXT

Baicalin, a major flavonoid extracted from Scutellaria baicalensis Georgi (Lamiaceae), has been shown to exert therapeutic effects on pulmonary fibrosis (PF).

OBJECTIVE

To use serum metabolomics combined with biochemical and histopathological analyses to clarify anti-PF mechanisms of baicalin on metabolic pathways and the levels of potential biomarkers.

MATERIALS AND METHODS

Forty male Sprague-Dawley rats were randomly divided into the control, PF model, prednisolone acetate-treated (4.2 mg/kg/day) and baicalin-treated (25 and 100 mg/kg/day) groups. A rat model of PF was established using a tracheal injection of bleomycin, and the respective drugs were administered intragastrically for 4 weeks. Histomorphology of lung tissue was examined after H&E and Masson's trichrome staining. Biochemical indicators including SOD, MDA and HYP were measured. Serum-metabonomic analysis based on UPLC-Q-TOF/MS was used to clarify the changes in potential biomarkers among different groups of PF rats.

RESULTS

Both doses of baicalin effectively alleviated bleomycin-induced pathological changes, and increased the levels of SOD (from 69.48 to 99.50 and 112.30, respectively), reduced the levels of MDA (from 10.91 to 5.0 and 7.53, respectively) and HYP (from 0.63 to 0.41 and 0.49, respectively). Forty-eight potential biomarkers associated with PF were identified. Meanwhile, the metabolic profiles and fluctuating metabolite levels were normalized or partially reversed after baicalin treatment. Furthermore, baicalin was found to improve PF potentially by the regulation of four key biomarkers involving taurine and hypotaurine metabolism, glutathione metabolism, and glycerophospholipid metabolism.

CONCLUSIONS

These findings revealed the anti-fibrotic mechanisms of baicalin and it may be considered as an effective therapy for PF.

Recent Advances in Fluorescence Imaging of Pulmonary Fibrosis in Animal Models

Pulmonary fibrosis (PF) is a lung disease that may cause impaired gas exchange and respiratory failure while being difficult to treat. Rapid, sensitive, and accurate detection of lung tissue and cell changes is essential for the effective diagnosis and treatment of PF. Currently, the commonly-used high-resolution computed tomography (HRCT) imaging has been challenging to distinguish early PF from other pathological processes in the lung structure. Magnetic resonance imaging (MRI) using hyperpolarized gases is hampered by the higher cost to become a routine diagnostic tool. As a result, the development of new PF imaging technologies may be a promising solution. Here, we summarize and discuss recent advances in fluorescence imaging as a talented optical technique for the diagnosis and evaluation of PF, including collagen imaging, oxidative stress, inflammation, and PF-related biomarkers. The design strategies of the probes for fluorescence imaging (including multimodal imaging) of PF are briefly described, which can provide new ideas for the future PF-related imaging research. It is hoped that this review will promote the translation of fluorescence imaging into a clinically usable assay in PF.

Severe progression of idiopathic pulmonary fibrosis post-COVID-19 infection

A 79-year-old woman presented with a week-long history of shortness of breath. She had a background of idiopathic pulmonary fibrosis (IPF) which was stable and had not required any antifibrotic treatment. A month prior to this presentation, she was admitted with COVID-19 pneumonia, with maximal oxygen requirement of 2 L, but was discharged without need for supplemental oxygen. On readmission, she was found to have severe, rapidly progressive pulmonary fibrosis. After all precipitating causes were ruled out, it was felt her recent COVID-19 infection was the exacerbating factor causing progression of pulmonary fibrosis. COVID-19 infection has been hypothesised to cause long term pulmonary fibrosis, but this is the first case highlighting COVID-19 infection as the causative agent exacerbating IPF.

Iron oxide nanoparticles augment the intercellular mitochondrial transfer-mediated therapy

The transfer of mitochondria between cells has recently been revealed as a spontaneous way to protect the injured cells. However, the utilization of this natural transfer process for disease treatment is so far limited by its unsatisfactory transfer efficiency and selectivity. Here, we demonstrate that iron oxide nanoparticles (IONPs) can augment the intercellular mitochondrial transfer from human mesenchymal stem cells (hMSCs) selectively to diseased cells, owing to the enhanced formation of connexin 43–containing gap junctional channels triggered by ionized IONPs. In a mouse model of pulmonary fibrosis, the IONP-engineered hMSCs achieve a remarkable mitigation of fibrotic progression because of the promoted intercellular mitochondrial transfer, with no serious safety issues identified. The present study reports a potential method of using IONPs to enable hMSCs for efficient and safe transfer of mitochondria to diseased cells to restore mitochondrial bioenergetics.

Chest high-resolution computed tomography in patients with connective tissue disease: pulmonary conditions beyond "the usual suspects"

The term "connective tissue diseases" (CTDs) refers to a heterogeneous group of autoimmune disorders, including systemic sclerosis, rheumatoid arthritis, Sjögren's syndrome, systemic lupus erythematosus, polymyositis, dermatomyositis, antisynthetase syndrome, and mixed connective tissue disease. Chest high-resolution computed tomography (HRCT) is the imaging method of choice for evaluating patients with known or suspected CTD-related interstitial lung disease (CTD-ILD), a complication accounting for substantial morbidity and mortality. While specific HRCT patterns and signs of CTD-ILD have been extensively described (hence the designation "the usual suspects"), the knowledge of various, less frequent conditions involving the lungs in patients with CTD would help the radiologist produce a clinically valuable report, thus potentially influencing patient management. This paper aims to provide an up-to-date review of various unusual pulmonary CTD-related conditions the radiologist should be aware of; namely, acute exacerbation of CTD-ILD, CTD-related interstitial lung abnormalities, lung amyloidosis, MALT lymphoma, antisynthetase syndrome, pleuroparenchymal fibroelastosis-like lesion, drug-induced ILD, combined pulmonary fibrosis and emphysema, and pulmonary hypertension. For each condition, the chest HRCT appearance and the key histopathological and clinical features are resumed, helping the radiologist participate actively in the multidisciplinary discussion of complex clinical cases.

Clinical Characteristics, Treatments and Outcomes of 18 Lung Transplant Recipients with COVID-19

We report clinical features, treatments and outcomes in 18 lung transplant recipients with laboratory confirmed SARS-CoV-2 infection. We performed a single center, retrospective case series study of lung transplant recipients, who tested positive for SARS-CoV-2 between 1 February 2020 and 1 March 2021. Clinical, laboratory and radiology findingswere obtained. Treatment regimens and patient outcome data were obtained by reviewing the electronic medical record. Mean age was 49.9 (22–68) years, and twelve (67%) patients were male. The most common symptoms were fever (n = 9, 50%), nausea/vomiting (n = 7, 39%), cough (n = 6, 33%), dyspnea (n = 6, 33%) and fatigue (n = 6, 33%). Headache was reported by five patients (28%). The most notable laboratory findings were elevated levels of C-reactive protein (CRP) and lactate dehydrogenase (LDH). Computed Tomography (CT) of the chest was performed in all hospitalized patients (n = 11, 7%), and showed ground-glass opacities (GGO) in 11 patients (100%), of whom nine (82%) had GGO combined with pulmonary consolidations. Six (33%) patients received remdesivir, five (28%) intravenous dexamethasone either alone or in combination with remdesivir, and 15 (83%) were treated with broad spectrum antibiotics including co-amoxicillin, tazobactam-piperacillin and meropenem. Four (22%) patients were transferred to the intensive care unit, two patients (11%) required invasive mechanical ventilation who could not be successfully extubated and died. Eighty-nine percent of our patients survived COVID-19 and were cured. Two patients with severe COVID-19 did not survive.

Post-COVID-19 Pulmonary Fibrosis: Novel Sequelae of the Current Pandemic

Since the initial identification of the novel coronavirus SARS-CoV-2 in December 2019, the COVID-19 pandemic has become a leading cause of morbidity and mortality worldwide. As effective vaccines and treatments begin to emerge, it will become increasingly important to identify and proactively manage the long-term respiratory complications of severe disease. The patterns of imaging abnormalities coupled with data from prior coronavirus outbreaks suggest that patients with severe COVID-19 pneumonia are likely at an increased risk of progression to interstitial lung disease (ILD) and chronic pulmonary vascular disease. In this paper, we briefly review the definition, classification, and underlying pathophysiology of interstitial lung disease (ILD). We then review the current literature on the proposed mechanisms of lung injury in severe COVID-19 infection, and outline potential viral- and immune-mediated processes implicated in the development of post-COVID-19 pulmonary fibrosis (PCPF). Finally, we address patient-specific and iatrogenic risk factors that could lead to PCPF and discuss strategies for reducing risk of pulmonary complications/sequelae.

Correlation of Krebs von den Lungen-6 and fibronectin with pulmonary fibrosis in coronavirus disease 2019

OBJECTIVE

Coronavirus Disease 2019 (COVID-19) caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is still spreading worldwide, which may progress to pulmonary fibrosis (PF), leading to the worsen outcome. As the markers of lung injury, the correlation of Krebs von den Lungen-6 (KL-6) and fibronectin (Fn) with pulmonary fibrosis in COVID-19 was still unclear.

METHODS

113 patients diagnosed as COVID-19 were enrolled in this retrospective study, and divided into three categories as mild, moderate and severe cases. The concentrations of serum KL-6 and Fn at hospital admission were tested using the method of latex agglutination assay and immunoturbidimetic assay, respectively.

RESULTS

Compared with that in the non-severe COVID-19 cases and normal control subjects, serum KL-6 concentration on admission was significantly higher in the severe group, which was positively correlated with C-reactive protein, and negatively correlated with lymphocytes count. Whereas, no obvious elevation in serum Fn concentration was investigated in COVID-19 patients with the different phenotypes. The severe cases displayed the higher incident rate of pulmonary fibrosis at hospital discharge. Compared with non-PF patients, the COVID-19 cases with PF had the higher serum KL-6 values.

CONCLUSION

Serum KL-6 concentration was significantly elevated in severe COVID-19 patients, which may be useful for evaluating the disease severity. For early prevention of the development of pulmonary fibrosis, high concentrations of serum KL-6 in the early stage of COVID-19 should be paid close attention.

Persistence of COVID-19 Symptoms after Recovery in Mexican Population

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease (COVID-19), a highly contagious infectious disease that has caused many deaths worldwide. Despite global efforts, it continues to cause great losses, and leaving multiple unknowns that we must resolve in order to face the pandemic more effectively. One of the questions that has arisen recently is what happens, after recovering from COVID-19. For this reason, the objective of this study is to identify the risk of presenting persistent symptoms in recovered from COVID-19. This case-control study was conducted in one state of Mexico. Initially the data were obtained from the participants, through a questionnaire about symptoms that they had at the moment of the interview. Initially were captured the collected data, to make a dataset. After the pre-processed using the R project tool to eliminate outliers or missing data. Obtained finally a total of 219 participants, 141 recovered and 78 controls. It was used confidence level of 90% and a margin of error of 7%. From results it was obtained that all symptoms have an associated risk in those recovered. The relative risk of the selected symptoms in the recovered patients goes from 3 to 22 times, being infinite for the case of dyspnea, due to the fact that there is no control that presents this symptom at the moment of the interview, followed by the nausea and the anosmia with a RR of 8.5. Therefore, public health strategies must be rethought, to treat or rehabilitate, avoiding chronic problems in patients recovered from COVID-19.

Immunopathology of galectin-3: an increasingly promising target in COVID-19

The pandemic brought on by the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) has become a global health crisis, with over 22 million confirmed cases and 777,000 fatalities due to coronavirus disease 2019 (COVID-19) reported worldwide. The major cause of fatality in infected patients, now referred to as the "Cytokine Storm Syndrome" (CSS), is a direct result of aberrant immune activation following SARS-CoV2 infection and results in excess release of inflammatory cytokines, such as interleukin (IL)-1, tumor necrosis factor α (TNF-α), and IL-6, by macrophages, monocytes, and dendritic cells. Single cell analysis has also shown significantly elevated levels of galectin 3 (Gal-3) in macrophages, monocytes, and dendritic cells in patients with severe COVID-19 as compared to mild disease. Inhibition of Gal-3 reduces the release of IL-1, IL-6, and TNF-α from macrophages in vitro, and as such may hold promise in reducing the incidence of CSS. In addition, Gal-3 inhibition shows promise in reducing transforming growth factor ß (TGF-ß) mediated pulmonary fibrosis, likely to be a major consequence in survivors of severe COVID-19. Finally, a key domain in the spike protein of SARS-CoV2 has been shown to bind N-acetylneuraminic acid (Neu5Ac), a process that may be essential to cell entry by the virus. This Neu5Ac-binding domain shares striking morphological, sequence, and functional similarities with human Gal-3. Here we provide an updated review of the literature linking Gal-3 to COVID-19 pathogenesis. Dually targeting galectins and the Neu5Ac-binding domain of SARS-CoV2 shows tentative promise in several stages of the disease: preventing viral entry, modulating the host immune response, and reducing the post-infectious incidence of pulmonary fibrosis.