Efficacy and safety of nintedanib for pulmonary fibrosis in severe pneumonia induced by COVID-19: An interventional study

Impact of Anti-fibrotic Medications on Post-COVID-19 Pulmonary Fibrosis: A Systematic Review and Meta-analysis

OBJECTIVES

The impact of anti-fibrotic medications on pulmonary fibrosis caused by COVID-19 remains inconclusive and lacks systematic investigation. This study assessed the efficacy of anti-fibrotic drugs in addressing post-COVID-19 lung fibrosis.

METHODS

We searched PubMed, Web of Science, Embase, and the Cochrane Library until June 15, 2024. The meta-analysis was performed using Review Manager. Heterogeneity was evaluated utilizing I2 statistic, and publication bias was assessed via funnel plots.

RESULTS

The study (CRD42024552847) included 7 trials with 496 participants. No significant differences were observed in chest CT score (SMD= -0.60, 95% CI: -1.33 to 0.12, P= 0.10), length of hospital stay (MD= -1.34, 95% CI: -4.39 to 1.70, P= 0.39), and mortality (OR= 0.91, 95% CI: 0.50 to 1.64, P= 0.75) between anti-fibrosis and standard treatment groups. Notable improvements in pulmonary function were observed with anti-fibrotic drugs, as indicated by FEV1%pred (MD= 23.95, 95% CI: 12.24 to 35.67, P< 0.0001) and FEV1/FVC (MD= 18.17, 95% CI: 11.96 to 24.38, P< 0.00001).

CONCLUSIONS

Anti-fibrotic medications may help reduce fibrotic lesions and improve pulmonary function in post-COVID-19 pulmonary fibrosis, but their practical use is currently based more on theory than on solid medical evidence. Currently, in clinical practice, the use of anti-fibrotic drugs in these patients primarily relies on empirical treatment. Further clinical studies are imperative to bolster its credibility for future applications.

Nintedanib Mitigates Radiation-Induced Pulmonary Fibrosis by Suppressing Epithelial Cell Inflammatory Response and Inhibiting Fibroblast-to-Myofibroblast Transition

Radiation-induced pulmonary fibrosis (RIPF) represents a serious complication observed in individuals undergoing thoracic radiation therapy. Currently, effective interventions for RIPF are unavailable. Prior research has demonstrated that nintedanib, a Food and Drug Administration (FDA)-approved anti-fibrotic agent for idiopathic pulmonary fibrosis, exerts therapeutic effects on chronic fibrosing interstitial lung disease. This research aimed to investigate the anti-fibrotic influences of nintedanib on RIPF and reveal the fundamental mechanisms. To assess its therapeutic impact, a mouse model of RIPF was established. The process involved nintedanib administration at various time points, both prior to and following thoracic radiation. In the RIPF mouse model, an assessment was conducted on survival rates, body weight, computed tomography features, histological parameters, and changes in gene expression. In vitro experiments were performed to discover the mechanism underlying the therapeutic impact of nintedanib on RIPF. Treatment with nintedanib, administered either two days prior or four weeks after thoracic radiation, significantly alleviated lung pathological changes, suppressed collagen deposition, and improved the overall health status of the mice. Additionally, nintedanib demonstrated significant mitigation of radiation-induced inflammatory responses in epithelial cells by inhibiting the PI3K/AKT and MAPK signaling pathways. Furthermore, nintedanib substantially inhibited fibroblast-to-myofibroblast transition by suppressing the TGF-β/Smad and PI3K/AKT/mTOR signaling pathways. These findings suggest that nintedanib exerts preventive and therapeutic effects on RIPF by modulating multiple targets instead of a single anti-fibrotic pathway and encourage the further clinical trials to determine the efficacy of nintedanib in patients with RIPF.

Pirfenidone and Nintedanib in Pulmonary Fibrosis: Lights and Shadows

Pirfenidone and Nintedanib are specific drugs used against idiopathic pulmonary fibrosis (IPF) that showed efficacy in non-IPF fibrosing interstitial lung diseases (ILD). Both drugs have side effects that affect patients in different ways and have different levels of severity, making treatment even more challenging for patients and clinicians. The present review aims to assess the effectiveness and potential complications of Pirfenidone and Nintedanib treatment regimens across various ILD diseases. A detailed search was performed in relevant articles published between 2018 and 2023 listed in PubMed, UpToDate, Google Scholar, and ResearchGate, supplemented with manual research. The following keywords were searched in the databases in all possible combinations: Nintedanib; Pirfenidone, interstitial lung disease, and idiopathic pulmonary fibrosis. The most widely accepted method for evaluating the progression of ILD is through the decline in forced vital capacity (FVC), as determined by respiratory function tests. Specifically, a decrease in FVC over a 6-12-month period correlates directly with increased mortality rates. Antifibrotic drugs Pirfenidone and Nintedanib have been extensively validated; however, some patients reported several side effects, predominantly gastrointestinal symptoms (such as diarrhea, dyspepsia, and vomiting), as well as photosensitivity and skin rashes, particularly associated with Pirfenidone. In cases where the side effects are extremely severe and are more threatening than the disease itself, the treatment has to be discontinued. However, further research is needed to optimize the use of antifibrotic agents in patients with PF-ILDs, which could slow disease progression and decrease all-cause mortality. Finally, other studies are requested to establish the treatments that can stop ILD progression.

The effect of antifibrotic agents on acute respiratory failure in COVID-19 patients: a retrospective cohort study from TriNetX US collaborative networks

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has had a significant impact on global health and economies, resulting in millions of infections and deaths. This retrospective cohort study aimed to investigate the effect of antifibrotic agents (nintedanib and pirfenidone) on 1-year mortality in COVID-19 patients with acute respiratory failure.

METHODS

Data from 61 healthcare organizations in the TriNetX database were analyzed. Adult patients with COVID-19 and acute respiratory failure were included. Patients with a pre-existing diagnosis of idiopathic pulmonary fibrosis before their COVID-19 diagnosis were excluded. The study population was divided into an antifibrotic group and a control group. Propensity score matching was used to compare outcomes, and hazard ratios (HR) for 1-year mortality were calculated.

RESULTS

The antifibrotic group exhibited a significantly lower 1-year mortality rate compared to the control group. The survival probability at the end of the study was 84.42% in the antifibrotic group and 69.87% in the control group. The Log-Rank test yielded a p-value of less than 0.001. The hazard ratio was 0.434 (95% CI: 0.264-0.712), indicating a significant reduction in 1-year mortality in the antifibrotic group. Subgroup analysis demonstrated significantly improved 1-year survival in patients receiving nintedanib treatment and during periods when the Wuhan strain was predominant.

DISCUSSION

This study is the first to demonstrate a survival benefit of antifibrotic agents in COVID-19 patients with acute respiratory failure. Further research and clinical trials are needed to confirm the efficacy of these antifibrotic agents in the context of COVID-19 and acute respiratory failure.

Targeting Senescent Alveolar Epithelial Cells Using Engineered Mesenchymal Stem Cell-Derived Extracellular Vesicles To Treat Pulmonary Fibrosis

Type 2 alveolar epithelial cell (AEC2) senescence is crucial to the pathogenesis of pulmonary fibrosis (PF). The nicotinamide adenine dinucleotide (NAD+)-consuming enzyme cluster of differentiation 38 (CD38) is a marker of senescent cells and is highly expressed in AEC2s of patients with PF, thus rendering it a potential treatment target. Umbilical cord mesenchymal stem cell (MSC)-derived extracellular vesicles (MSC-EVs) have emerged as a cell-free treatment with clinical application prospects in antiaging and antifibrosis treatments. Herein, we constructed CD38 antigen receptor membrane-modified MSC-EVs (CD38-ARM-MSC-EVs) by transfecting MSCs with a lentivirus loaded with a CD38 antigen receptor-CD8 transmembrane fragment fusion plasmid to target AEC2s and alleviate PF. Compared with MSC-EVs, the CD38-ARM-MSC-EVs engineered in this study showed a higher expression of the CD38 antigen receptor and antifibrotic miRNAs and targeted senescent AEC2s cells highly expressing CD38 in vitro and in naturally aged mouse models after intraperitoneal administration. CD38-ARM-MSC-EVs effectively restored the NAD+ levels, reversed the epithelial-mesenchymal transition phenotype, and rejuvenated senescent A549 cells in vitro, thereby mitigating multiple age-associated phenotypes and alleviating PF in aged mice. Thus, this study provides a technology to engineer MSC-EVs and support our CD38-ARM-MSC-EVs to be developed as promising agents with high clinical potential against PF.

Emerging opportunities to treat idiopathic pulmonary fibrosis: Design, discovery, and optimizations of small-molecule drugs targeting fibrogenic pathways

Idiopathic pulmonary fibrosis (IPF) is the most common fibrotic form of idiopathic diffuse lung disease. Due to limited treatment options, IPF patients suffer from poor survival. About ten years ago, Pirfenidone (Shionogi, 2008; InterMune, 2011) and Nintedanib (Boehringer Ingelheim, 2014) were approved, greatly changing the direction of IPF drug design. However, limited efficacy and side effects indicate that neither can reverse the process of IPF. With insights into the occurrence of IPF, novel targets and agents have been proposed, which have fundamentally changed the treatment of IPF. With the next-generation agents, targeting pro-fibrotic pathways in the epithelial-injury model offers a promising approach. Besides, several next-generation IPF drugs have entered phase II/III clinical trials with encouraging results. Due to the rising IPF treatment requirements, there is an urgent need to completely summarize the mechanisms, targets, problems, and drug design strategies over the past ten years. In this review, we summarize known mechanisms, target types, drug design, and novel technologies of IPF drug discovery, aiming to provide insights into the future development and clinical application of next-generation IPF drugs.

Coronavirus disease 2019 in a patient with pulmonary fibrosis and emphysema: An autopsy report

Various diseases (e.g., hypertension and diabetes) are risk factors for the exacerbation of coronavirus 2019 (COVID-19). Patients with chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD) tend to develop severe COVID-19. Patients with severe COVID-19 present with acute respiratory distress syndrome (ARDS), and many COVID-19-related ARDS survivors eventually develop fibrosis. However, the appropriate management of patients with COVID-19 and ILD and post-COVID-19 ILD remains unclear. Thus, a better understanding of the pathology that exacerbates COVID-19 in patients with ILD is needed. We report the autopsy results of a patient with COVID-19 and combined pulmonary fibrosis and emphysema, whose lung organization and fibrosis progressed after the acute phase of infection. Histopathological findings suggest that fatal pulmonary fibrosis persists after the negative conversion of SARS-CoV-2. Elucidating the cause of death by autopsy may help determine therapeutic strategies in patients with COVID-19 and ILD. Vaccination and early administration of anti-inflammatory drugs or antifibrotic agents may be crucial for preventing disease progression and fatal lung fibrosis. This report aims to clarify the histopathological features of COVID-19 in patients with ILD via autopsy and discuss treatment strategies.

Association Between COVID-19 Infection and Pulmonary Fibrosis: A Nested Case-Control Study

BACKGROUND

Pulmonary fibrosis is associated with significant morbidity. Data are scarce on the link between coronavirus disease (COVID-19) and pulmonary fibrosis. We aimed to assess the association between COVID-19 with pulmonary fibrosis.

METHODS

We conducted a nested case-control study in a cohort of 2,894,801 adults without a diagnosis of pulmonary fibrosis. The underlying cohort consisted of members of the largest healthcare provider in Israel aged 18 years or older as of May 1, 2020. Subjects were followed up from cohort entry until June 30, 2022, for the occurrence of pulmonary fibrosis. Ten randomly selected controls were matched to each case of pulmonary fibrosis on age, sex, and calendar time. To account for surveillance bias a lag time of 60 days was used for ascertainment of prior COVID-19 and COVID-19 severity.

RESULTS

During follow-up 1284 patients were newly diagnosed with pulmonary fibrosis and matched with 12,840 controls. Multivariable conditional logistic-regression models showed that the odds ratio for pulmonary fibrosis was 1.80 (95% confidence interval, 1.47-2.19) in patients with COVID-19 compared with no COVID-19. The multivariable odds ratio for pulmonary fibrosis was 1.33 (1.06-1.68), 2.98 (1.16-7.65), and 9.30 (5.77-14.98) for mild, moderate, and severe COVID-19, respectively, compared with no COVID-19. The magnitude of the association was attenuated but remained statistically significant for severe disease when the lag time was extended to 180 days (1.08 [0.78-1.49], 2.37 [0.75-7.46], and 5.34 [2.75-10.36] for mild, moderate, and severe COVID-19, respectively).

CONCLUSIONS

COVID-19 appears to be associated with an increased risk of pulmonary fibrosis and the magnitude of the association increases with COVID-19 severity.

Longitudinal x-ray based lung function measurement for monitoring Nintedanib treatment response in a mouse model of lung fibrosis

Lung fibrosis (LF) is a chronic progressive, incurable, and debilitating condition of the lung, which is associated with different lung disease. Treatment options are still sparse. Nintedanib, an oral tyrosine kinase inhibitor, significantly slows the LF progression. However, there is a strong need of further research and the development of novel therapies. In this study, we used a correlative set-up that combines X-ray based lung function (XLF) with microCT and whole body plethysmography (WBP) for a comprehensive functional and structural evaluation of lung fibrosis (LF) as well as for monitoring response to orally administered Nintedanib in the mouse model of bleomycin induced LF. The decline in lung function as early as one week after intratracheal bleomycin instillation was reliably detected by XLF, revealing the lowest decay rate in the LF mice compared to healthy ones. Simultaneously performed microCT and WBP measurements corroborated XLF findings by exhibiting reduced lung volume [Formula: see text] and tidal volume [Formula: see text]. In LF mice XLF also revealed profound improvement in lung function one week after Nintedanib treatment. This positive response to Nintedanib therapy was further substantiated by microCT and WBP measurements which also showed significantly improved [Formula: see text] and [Formula: see text] in the Nintedanib treated mice. By comparing the XLF data to structural features assessing the extent of fibrosis obtained by ex-vivo high-resolution synchrotron radiation-based imaging and classical histology we demonstrate that: (1) a simple low dose x-ray measurement like XLF is sensitive enough to pick up treatment response, (2) Nintedanib treatment successfully improved lung function in a bleomycin induced LF mouse model and (3) differences between the fully restored lung function and the partially reduced fibrotic burden compared to healthy and untreated mice. The presented analysis pipeline underlines the importance of a combined functional and anatomical readout to reliably measure treatment response and could easily be adapted to other preclinical lung disease models.

Pulmonary fibrosis in COVID-19: mechanisms, consequences and targets

Pulmonary fibrosis is characterized by extracellular deposition in the lung primarily collagen but also other ECM molecules. The primary cell type responsible for this is the myofibroblast, and this can be induced by various stressors and signals. Infections be they bacterial or viral can cause pulmonary fibrosis (PF). In 2019, severe acute respiratory syndrome coronavirus 2 (SAR-CoV-2) originated in Wuhan, China, has led to a worldwide pandemic and can lead to acute respiratory distress and lung fibrosis. The virus itself can be cleared, but patients may develop long-term PF, which can be debilitating and life-limiting. There is a significantly perturbed immune response that shapes the fibrotic response leading to fibrosis. Given the importance of PF irrespective of cause, understanding the similarities and differences in pathogenesis caused by SARS-CoV-2-induced PF may yield new therapeutic targets. This review examines the pathology associated with the disease and discusses possible targets.

Prolonged-release pirfenidone in patients with pulmonary fibrosis as a phenotype of post-acute sequelae of COVID-19 pneumonia. Safety and efficacy

INTRODUCTION

One of the major concerns with post-acute sequelae of COVID-19 (PASC) is the development of pulmonary fibrosis, for which no approved pharmacological treatment exists. Therefore, the primary aim of this open-label study was to evaluate the safety and the potential clinical efficacy of a prolonged-release pirfenidone formulation (PR-PFD) in patients having PASC-pulmonary fibrosis.

METHODS

Patients with PASC-pulmonary fibrosis received PR-PFD 1800 mg/day (1200 mg in the morning after breakfast and 600 mg in the evening after dinner) for three months. Blood samples were taken to confirm the pharmacokinetics of PR-PFD, and adverse events (AEs) were evaluated monthly using a short questionnaire. Symptoms, dyspnea, and pulmonary function tests (spirometry, diffusing capacity for carbon monoxide, plethysmography, and 6-min walk test [6MWT]) were evaluated at baseline, and one and three months after having started the PR-PFD treatment.

RESULTS

Seventy subjects with mild to moderate lung restriction were included. The most common AEs were diarrhea (23%), heartburn (23%), and headache (16%), for which no modifications in the drug study were needed. Two patients died within the first 30 days of enrolment, and three opted not to continue the study, events which were not associate with PR-PFD. Pulmonary function testing, 6MWT, dyspnea, symptoms, and CT scan significantly improved after three months of treatment with PR-PFD.

CONCLUSION

In patients with PASC pulmonary fibrosis, three months' treatment with PR-PFD was safe and showed therapeutic efficacy. Still, it remains to be seen whether the pulmonary fibrotic process remains stable, becomes progressive or will improve.

Post-COVID-19 pulmonary fibrosis: An ongoing concern

Coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 rapidly spread across the globe causing over 6 million deaths and major compromization of health facilities. The vast majority of survivors post-COVID-19 are left with variable degrees of health sequelae including pulmonary, neurological, psychological, and cardiovascular complications. Post-COVID-19 pulmonary fibrosis is one of the major concerns arising after the recovery from this pandemic. Risk factors for post-COVID-19 pulmonary fibrosis include age, male sex, and the severity of COVID-19 disease. High-resolution computed tomography provides diagnostic utility to diagnose pulmonary fibrosis as it provides more details regarding the pattern and the extent of pulmonary fibrosis. Emerging data showing similarities between post-COVID-19 pulmonary fibrosis and idiopathic pulmonary fibrosis, finding that needs further exploration. The management of post-COVID-19 pulmonary fibrosis depends on many factors but largely relies on excluding other causes of pulmonary fibrosis, the extent of fibrosis, and physiological impairment. Treatment includes immunosuppressants versus antifibrotics or both.

Nintedanib inhibits normal human vitreous-induced epithelial-mesenchymal transition in human retinal pigment epithelial cells

PURPOSE

In this study, we aim to investigate the potential of nintedanib as a therapeutic approach to proliferative vitreoretinopathy (PVR), which is the leading cause of failure in retinal detachment repair. PVR is characterized by the epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells, and understanding the effects of nintedanib on EMT in the normal human vitreous (HV)-induced RPE cells is crucial.

METHODS

Our research focuses on assessing the impact of nintedanib on HV-induced EMT in human retinal pigment epithelial (ARPE-19) cells in vitro. We employed various techniques, including quantitative real-time PCR (qPCR), western blot analysis, and immunofluorescence staining, to evaluate the mRNA and protein expression of EMT biomarkers in HV-induced ARPE-19 cells. Additionally, we measured the proliferation of RPE cells using cell counting, CCK-8, and Ki-67 assays. Migration was assessed through wound healing and transwell migration assays, while contraction was determined using a collagen gel contraction assay. Morphological changes were examined using phase-contrast microscopy.

RESULTS

Our results demonstrate that nintedanib selectively attenuates the upregulation of mesenchymal markers in HV-induced ARPE-19 cells, at both the mRNA and protein levels. Furthermore, nintedanib effectively suppresses the HV-induced proliferation, migration, and contraction of ARPE-19 cells, while maintaining the cells' basal activity. These findings strongly suggest that nintedanib exhibits protective effects against EMT in ARPE-19 cells and could be a promising therapeutic option for PVR.

CONCLUSIONS

By elucidating the anti-EMT effects of nintedanib in HV-induced RPE cells, our study highlights the potential of this oral triple tyrosine kinase inhibitor in the treatment of PVR. These findings contribute to the growing body of research aimed at developing novel strategies to prevent and manage PVR, ultimately improving the success rates of retinal detachment repair.

The Effect of Potassium Canrenoate (Mineralocorticoid Receptor Antagonist) on the Markers of Inflammation in the Treatment of COVID-19 Pneumonia and Fibrosis-A Secondary Analysis of Randomized Placebo-Controlled Clinical Trial

In March 2020, the World Health Organization (WHO) announced a global pandemic of coronavirus disease 2019 (COVID-19) that presented mainly as an acute infection of the lower respiratory tract (pneumonia), with multiple long-term consequences, including lung fibrosis. The aim of this study was to evaluate the influence of potassium canrenoate on inflammatory markers in the treatment of COVID-19 pneumonia. A randomized clinical trial (RCT) of intravenous potassium canrenoate vs. placebo was performed between December 2020 and November 2021. This study is a secondary analysis of that RCT. In the final analysis, a total of 49 hospitalized patients were included (24 allocated to the potassium canrenoate group and 25 to the placebo group). Patients were assessed by serum testing and blood cell cytometry on day 1 and day 7 of the intervention. Age, sex, and body mass index were not significantly different between the placebo group and intervention group. Although there was a significantly higher rate of ischemic heart disease in the placebo group, rates of other preexisting comorbidities were not significantly different. There were no significant differences in the inflammatory parameters between the potassium canrenoate and placebo groups on day 1 and day 7. However, the intragroup comparisons using Wilcoxon's test showed significant differences between day 1 and day 7. The CD3% for potassium canrenoate increased significantly between day 1 and day 7 (12.85 ± 9.46; 11.55 vs. 20.50 ± 14.40; 17.80; p = 0.022), while the change in the placebo group was not significant (15.66 ± 11.39; 12.65 vs. 21.16 ± 15.37; 16.40; p = 0.181). The IL-1ß total count [%] increased over time for both potassium canrenoate (0.68 ± 0.58; 0.45 vs. 1.27 ± 0.83; 1.20; p = 0.004) and placebo (0.61 ± 0.59; 0.40 vs. 1.16 ± 0.91; 1.00; p = 0.016). The TNF-α total count (%) decreased significantly between day 1 and day 7 for potassium canrenoate (0.54 ± 0.45; 0.40 vs. 0.25 ± 0.23; 0.10; p = 0.031), but not for placebo (0.53 ± 0.47; 0.35 vs. 0.26 ± 0.31; 0.20; p = 0.056). Interleukin-6 (pg/mL) showed a significant decrease between day 1 and day 7 for potassium canrenoate (64.97 ± 72.52; 41.00 vs. 24.20 ± 69.38; 5.30; p = 0.006), but not the placebo group. This RCT has shown that the administration of potassium canrenoate to patients with COVID-19-induced pneumonia may be associated with significant changes in certain inflammatory markers (interleukin-6, CD3%, TNF-α), potentially related to pulmonary fibrosis. Although some positive trends were observed in the potassium canrenoate group, none of these observations reached statistical significance. Any possible benefits from the use of potassium canrenoate as an anti-inflammatory or antifibrotic drug in COVID-19 patients require further investigation.

COVID-19 and interstitial lung diseases: A multifaceted look at the relationship between the two diseases

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although it has been a fatal disease for many patients, the development of treatment strategies and vaccines have progressed over the past 3 years, and our society has become able to accept COVID-19 as a manageable common disease. However, as COVID-19 sometimes causes pneumonia, post-COVID pulmonary fibrosis (PCPF), and worsening of preexisting interstitial lung diseases (ILDs), it is still a concern for pulmonary physicians. In this review, we have selected several topics regarding the relationships between ILDs and COVID-19. The pathogenesis of COVID-19-induced ILD is currently assumed based mainly on the evidence of other ILDs and has not been well elucidated specifically in the context of COVID-19. We have summarized what has been clarified to date and constructed a coherent story about the establishment and progress of the disease. We have also reviewed clinical information regarding ILDs newly induced or worsened by COVID-19 or anti-SARS-CoV-2 vaccines. Inflammatory and profibrotic responses induced by COVID-19 or vaccines have been thought to be a risk for de novo induction or worsening of ILDs, and this has been supported by the evidence obtained through clinical experience over the past 3 years. Although COVID-19 has become a mild disease in most cases, it is still worth looking back on the above-reviewed information to broaden our perspectives regarding the relationship between viral infection and ILD. As a representative etiology for severe viral pneumonia, further studies in this area are expected.

Molecular mechanisms of COVID-19-induced pulmonary fibrosis and epithelial-mesenchymal transition

As the outbreak of COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) first broke out in Hubei Province, China, at the end of 2019. It has brought great challenges and harms to global public health. SARS-CoV-2 mainly affects the lungs and is mainly manifested as pulmonary disease. However, one of the biggest crises arises from the emergence of COVID-19-induced fibrosis. At present, there are still many questions about how COVID-19 induced pulmonary fibrosis (PF) occurs and how to treat and regulate its long-term effects. In addition, as an important process of fibrosis, the effect of COVID-19 on epithelial-mesenchymal transition (EMT) may be an important factor driving PF. This review summarizes the main pathogenesis and treatment mechanisms of COVID-19 related to PF. Starting with the basic mechanisms of PF, such as EMT, transforming growth factor-β (TGF-β), fibroblasts and myofibroblasts, inflammation, macrophages, innate lymphoid cells, matrix metalloproteinases and tissue inhibitors of metalloproteinases, hedgehog pathway as well as Notch signaling. Further, we highlight the importance of COVID-19-induced EMT in the process of PF and provide an overview of the related molecular mechanisms, which will facilitate future research to propose new clinical therapeutic solutions for the treatment of COVID-19-induced PF.

Role of Janus Kinase inhibitors in the management of pulmonary involvement due to Long COVID-19 disease: A case control study

OBJECTIVES

Ongoing symptomatic coronavirus disease 2019 (OSC) is defined as persistent symptoms beyond 4 weeks of acute illness. OSC leads to prolonged hospitalization and oxygen dependence. We aimed to find the outcome of Janus kinase inhibitors (JAKi) as a steroid-sparing agent to treat OSC.

METHODS

In this single-center case-controlled study comparing JAKi and corticosteroids in OSC cases, data of 41 cases out of 86 were included - 21 in the JAKi group and 20 in the corticosteroid group from 4 weeks of acute illness to the next 4 weeks. Clinical parameters and inflammatory markers were recorded. The primary outcome was to compare the proportion of patients who were able to maintain oxygen saturation ≥95% with any oxygen supplementation in the two groups.

RESULTS

The baseline clinical and demographic characteristics were similar in the two groups. The age was 53.65 ± 9.8 years and 51.48 ± 14.0 years in the corticosteroid group and JAKi group, respectively. At the baseline, 85% of patients in the corticosteroid group and 85.8% in the JAKi group were on oxygen support. The most common symptom in both groups was breathlessness followed by cough. Twenty percent of patients in the JAKi group received baricitinib and the remaining were given tofacitinib. At the time of follow-up, the majority of cases had a significant reduction in C-reactive protein (CRP) and D-dimer; however, the change in CRP and D-dimer was similar in both groups. The number of patients off oxygen support at 4 weeks was higher in the JAKi group (85% in the corticosteroid group vs. 95.2% in the JAKi group, P = 0.269), and the median time to liberation from oxygen support was significantly lower in JAKi group (19 days in corticosteroid group vs. 9 days in JAKi group, P < 0.001). The frequency of any adverse event was also higher in the corticosteroid group (70% vs. 23.8%, P = 0.003).

CONCLUSION

JAKi can be used as immunomodulatory drugs in hypoxic OSC cases having evidence of ongoing inflammation.

Pharmacological approaches to pulmonary fibrosis following COVID-19

Background: In the past few years, COVID-19 became the leading cause of morbidity and mortality worldwide. Although the World Health Organization has declared an end to COVID-19 as a public health emergency, it can be expected, that the emerging new cases at the top of previous ones will result in an increasing number of patients with post-COVID-19 sequelae. Despite the fact that the majority of patients recover, severe acute lung tissue injury can in susceptible individuals progress to interstitial pulmonary involvement. Our goal is to provide an overview of various aspects associated with the Post-COVID-19 pulmonary fibrosis with a focus on its potential pharmacological treatment options. Areas covered: We discuss epidemiology, underlying pathobiological mechanisms, and possible risk and predictive factors that were found to be associated with the development of fibrotic lung tissue remodelling. Several pharmacotherapeutic approaches are currently being applied and include anti-fibrotic drugs, prolonged use or pulses of systemic corticosteroids and non-steroidal anti-inflammatory and immunosuppressive drugs. In addition, several repurposed or novel compounds are being investigated. Fortunately, clinical trials focused on pharmacological treatment regimens for post-COVID-19 pulmonary fibrosis have been either designed, completed or are already in progress. However, the results are contrasting so far. High quality randomised clinical trials are urgently needed with respect to the heterogeneity of disease behaviour, patient characteristics and treatable traits. Conclusion: The Post-COVID-19 pulmonary fibrosis contributes to the burden of chronic respiratory consequences among survivors. Currently available pharmacotherapeutic approaches mostly comprise repurposed drugs with a proven efficacy and safety profile, namely, corticosteroids, immunosuppressants and antifibrotics. The role of nintedanib and pirfenidone is promising in this area. However, we still need to verify conditions under which the potential to prevent, slow or stop progression of lung damage will be fulfilled.

Mitochondrial citrate accumulation triggers senescence of alveolar epithelial cells contributing to pulmonary fibrosis in mice

Alveolar epithelial cell (AEC) senescence is implicated in the pathogenesis of pulmonary fibrosis (PF). However, the exact mechanism underlying AEC senescence during PF remains poorly understood. Here, we reported an unrecognized mechanism for AEC senescence during PF. We found that, in bleomycin (BLM)-induced PF mice, the expressions of isocitrate dehydrogenase 3α (Idh3α) and citrate carrier (CIC) were significantly down-regulated in the lungs, which could result in mitochondria citrate (citrate^mt) accumulation in our previous study. Notably, the down-regulation of Idh3α and CIC was related to senescence. The mice with AECs-specific Idh3α and CIC deficiency by adenoviral vector exhibited spontaneous PF and senescence in the lungs. In vitro, co-inhibition of Idh3α and CIC with shRNA or inhibitors triggered the senescence of AECs, indicating that accumulated citrate^mt triggers AEC senescence. Mechanistically, citrate^mt accumulation impaired the mitochondrial biogenesis of AECs. In addition, the senescence-associated secretory phenotype from senescent AECs induced by citrate^mt accumulation activated the proliferation and transdifferentiation of NIH3T3 fibroblasts into myofibroblasts. In conclusion, we show that citrate^mt accumulation would be a novel target for protection against PF that involves senescence.

Prospects of Novel and Repurposed Immunomodulatory Drugs against Acute Respiratory Distress Syndrome (ARDS) Associated with COVID-19 Disease

Acute respiratory distress syndrome (ARDS) is intricately linked with SARS-CoV-2-associated disease severity and mortality, especially in patients with co-morbidities. Lung tissue injury caused as a consequence of ARDS leads to fluid build-up in the alveolar sacs, which in turn affects oxygen supply from the capillaries. ARDS is a result of a hyperinflammatory, non-specific local immune response (cytokine storm), which is aggravated as the virus evades and meddles with protective anti-viral innate immune responses. Treatment and management of ARDS remain a major challenge, first, because the condition develops as the virus keeps replicating and, therefore, immunomodulatory drugs are required to be used with caution. Second, the hyperinflammatory responses observed during ARDS are quite heterogeneous and dependent on the stage of the disease and the clinical history of the patients. In this review, we present different anti-rheumatic drugs, natural compounds, monoclonal antibodies, and RNA therapeutics and discuss their application in the management of ARDS. We also discuss on the suitability of each of these drug classes at different stages of the disease. In the last section, we discuss the potential applications of advanced computational approaches in identifying reliable drug targets and in screening out credible lead compounds against ARDS.

Idiopathic Pulmonary Fibrosis and Post-COVID-19 Lung Fibrosis: Links and Risks

Idiopathic pulmonary fibrosis (IPF) is considered the paradigmatic example of chronic progressive fibrosing disease; IPF does not result from a primary immunopathogenic mechanism, but immune cells play a complex role in orchestrating the fibrosing response. These cells are activated by pathogen-associated or danger-associated molecular patterns generating pro-fibrotic pathways or downregulating anti-fibrotic agents. Post-COVID pulmonary fibrosis (PCPF) is an emerging clinical entity, following SARS-CoV-2 infection; it shares many clinical, pathological, and immune features with IPF. Similarities between IPF and PCPF can be found in intra- and extracellular physiopathological pro-fibrotic processes, genetic signatures, as well as in the response to antifibrotic treatments. Moreover, SARS-CoV-2 infection can be a cause of acute exacerbation of IPF (AE-IPF), which can negatively impact on IPF patients’ prognosis. In this narrative review, we explore the pathophysiological aspects of IPF, with particular attention given to the intracellular signaling involved in the generation of fibrosis in IPF and during the SARS-CoV-2 infection, and the similarities between IPF and PCPF. Finally, we focus on COVID-19 and IPF in clinical practice.

Post-COVID Interstitial Lung Disease and Other Lung Sequelae

As the world emerges from the COVID-19 pandemic, clinicians and researchers across the world are trying to understand the sequelae in patients recovered from COVID-19 infection. In this article, the authors review post-acute sequelae of SARS-COV-2, interstitial lung disease, and other lung sequelae in patients recovering from COVID-19 infection.

[SARS-CoV-2-Infection and Interstitial Lung Disease: Position paper of the German Respiratory Society]

The SARS-CoV-2 pandemic had a tremendous impact on diagnosis and treatment of interstitial lung diseases (ILD). Especially in the early phase of the pandemic, when the delta variant was prevailling, a huge number of viral pneumonias were observed, which worsened pre-existing, triggered de novo occurence or discovery of previously subclincal interstitial lung diseases. The effect of SARS-CoV-2 infection - without or with accompanying viral pneumonia - on the further development of pre-existing ILD as well of new pulmonary inflitrates and consolidiations is difficult to predict and poses a daily challenge to interdisciplinary ILD boards. This position paper of the German Respiratory Society (DGP e.V.) provides answers to the most pressing questions based on current knowledge.

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.

Hyaluronan in the pathogenesis of acute and post-acute COVID-19 infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recently emerged as the cause of a global pandemic. Infection with SARS-CoV-2 can result in COVID-19 with both acute and chronic disease manifestations that continue to impact many patients long after the resolution of viral replication. There is therefore great interest in understanding the host factors that contribute to COVID-19 pathogenesis. In this review, we address the role of hyaluronan (HA), an extracellular matrix polymer with roles in inflammation and cellular metabolism, in COVID-19 and critically evaluate the hypothesis that HA promotes COVID-19 pathogenesis. We first provide a brief overview of COVID-19 infection. Then we briefly summarize the known roles of HA in airway inflammation and immunity. We then address what is known about HA and the pathogenesis of COVID-19 acute respiratory distress syndrome (COVID-19 ARDS). Next, we examine potential roles for HA in post-acute SARS-CoV-2 infection (PASC), also known as "long COVID" as well as in COVID-associated fibrosis. Finally, we discuss the potential therapeutics that target HA as a means to treat COVID-19, including the repurposed drug hymecromone (4-methylumbelliferone). We conclude that HA is a promising potential therapeutic target for the treatment of COVID-19.

Post-COVID-19 interstitial lung disease: Insights from a machine learning radiographic model

Introduction

Post-acute sequelae of COVID-19 seem to be an emerging global crisis. Machine learning radiographic models have great potential for meticulous evaluation of post-COVID-19 interstitial lung disease (ILD).

Methods

In this multicenter, retrospective study, we included consecutive patients that had been evaluated 3 months following severe acute respiratory syndrome coronavirus 2 infection between 01/02/2021 and 12/5/2022. High-resolution computed tomography was evaluated through Imbio Lung Texture Analysis 2.1.

Results

Two hundred thirty-two (n = 232) patients were analyzed. FVC% predicted was ≥80, between 60 and 79 and <60 in 74.2% (n = 172), 21.1% (n = 49), and 4.7% (n = 11) of the cohort, respectively. DLCO% predicted was ≥80, between 60 and 79 and <60 in 69.4% (n = 161), 15.5% (n = 36), and 15.1% (n = 35), respectively. Extent of ground glass opacities was ≥30% in 4.3% of patients (n = 10), between 5 and 29% in 48.7% of patients (n = 113) and <5% in 47.0% of patients (n = 109). The extent of reticulation was ≥30%, 5-29% and <5% in 1.3% (n = 3), 24.1% (n = 56), and 74.6% (n = 173) of the cohort, respectively. Patients (n = 13, 5.6%) with fibrotic lung disease and persistent functional impairment at the 6-month follow-up received antifibrotics and presented with an absolute change of +10.3 (p = 0.01) and +14.6 (p = 0.01) in FVC% predicted at 3 and 6 months after the initiation of antifibrotic.

Conclusion

Post-COVID-19-ILD represents an emerging entity. A substantial minority of patients presents with fibrotic lung disease and might experience benefit from antifibrotic initiation at the time point that fibrotic-like changes are "immature." Machine learning radiographic models could be of major significance for accurate radiographic evaluation and subsequently for the guidance of therapeutic approaches.

Nintedanib in an elderly non-small-cell lung cancer patient with severe steroid-refractory checkpoint inhibitor-related pneumonitis: A case report and literature review

Immune checkpoint inhibitors tremendously improve cancer prognosis; however, severe-grade immune-related adverse events may cause premature death. Current recommendations for checkpoint inhibitor-related pneumonitis (CIP) treatment are mainly about immunosuppressive therapy, and anti-fibrotic agents are also needed, especially for patients with poor response to corticosteroids and a longer pneumonitis course. This is because fibrotic changes play an important role in the pathological evolution of CIP. Here, we report a case demonstrating that nintedanib is a promising candidate drug for CIP management or prevention, as it has potent anti-fibrotic efficacy and a safety profile. Moreover, nintedanib could partially inhibit tumor growth in patients with non-small-cell lung cancer, and its efficacy can be improved in combination with other anti-tumor therapies.

Nintedanib: a review of the properties, function, and usefulness to minimize COVID-19-induced lung injury

INTRODUCTION

In severe COVID-19 patients, acute respiratory distress syndrome (ARDS)-induced lung injury regularly causes a pulmonary fibrotic phase. There is no approved therapy for the COVID-19-induced pulmonary fibrosis. However, administration of an anti-fibrotic agent, in the early acute phase of the severe COVID-19 with ARDS, may improve the infection outcomes.

AREAS COVERED

In this review, the main characteristics of nintedanib and its usefulness to treat COVID-19-induced fibrosis were studied. In July 2022, a literature search was performed from PubMed, Google Scholar, and the WHO databases for studies focusing on the properties, function, efficacy, and safety of nintedanib against different lung injuries.

EXPERT OPINION

Nintedanib interferes with lung fibrosis and tumor angiogenesis by targeting multiple receptor tyrosine kinases (RTKs). Loss of RTKs activity leads to blocking downstream signaling cascades and inhibiting the proliferation and migration of lung fibroblasts. Targeting RTKs may be useful in the treatment of COVID-19 lung fibrosis. Nintedanib may be a superior agent compared to pirfenidone for the treatment of COVID-19 ARDS-related pulmonary fibrosis. Investigation of the efficacy and safety of nintedanib in the early stages of COVID-19-induced ARDS is critical since it may decrease the oxygen dependency and degree of lung fibrosis after the hospital discharge.

Pulmonary fibrosis in patients with COVID-19: A retrospective study

Background

Coronavirus disease 2019 (COVID-19) pandemic has caused substantial threats to people's physical health and lives, claiming the lives of over 6 million people worldwide. Although the mortality rate of COVID-19 is very low, many survivors may have different degrees and various sequelae. Previous studies have shown that pulmonary fibrosis (PF) were common on discharged COVID-19 patients, and PF itself is a poor prognostic factor.

Methods

227 COVID-19 hospitalized patients' clinical and laboratory data from the first 15 days following admission were collected in this retrospective study. Groups were based on with or without PF of COVID-19. Categorical variables were compared with the chi-square test or Fisher's exact test. Continuous variables were tested by Wilcoxon rank-sum test for the non-normal distribution. Spearman correlations were used to assess the correlations between PF with clinic parameters of multiple time points. Univariate and multivariate logistic regression were used to analyze for risk factors of COVID-19 patients with pulmonary fibrosis.

Results

Sixty cases of COVID-19 patients were diagnosed with PF. Compared with 167 non-PF patients, those with PF were older and had higher proportions of fever, shortness of breath, hemoptysis, abdominal pain, hypertension, cardiovascular, diabetes, high flow nasal cannula (HFNC), severe disease, and virus shedding duration. Furthermore, the correlation analysis between PF and clinic parameters showed that PF were positively related to the C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), and negatively correlated with hemoglobin (HGB) and albumin (ALB) at all time points in the first 15 days after admission. Moreover, We found that PF were significantly correlated with coagulation indexes prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (Fib) and fibrinolysis index D-Dimer at some phases. In addition, Univariate logistic regression analyses showed that age, fever, shortness of breath, hemoptysis, hypertension, cardiovascular, diabetes, HFNC, severe disease were the risk factors of COVID-19 patients with PF. However, multivariate logistic regression showed that age was the risk factor of COVID-19 patients with PF.

Conclusion

Combining various factors, advanced age is an independent risk factor of COVID-19 patients with PF. PF was significantly related with clinic parameter of inflammation/coagulopathy/fibrinolysis.

The Hidden Pandemic of COVID-19-Induced Organizing Pneumonia

Since the beginning of the COVID-19 pandemic, clinical, radiological, and histopathological studies have provided evidence that organizing pneumonia is a possible consequence of the SARS-CoV2 infection. This post-COVID-19 organizing pneumonia (PCOP) causes persisting dyspnea, impaired pulmonary function, and produces radiological abnormalities for at least 5 weeks after onset of symptoms. While most patients with PCOP recover within a year after acute COVID-19, 5-25% of cases need specialized treatment. However, despite substantial resources allocated worldwide to finding a solution to this problem, there are no approved treatments for PCOP. Oral corticosteroids produce a therapeutic response in a majority of such PCOP patients, but their application is limited by the anticipated high-relapse frequency and the risk of severe adverse effects. Herein, we conduct a systematic comparison of the epidemiology, pathogenesis, and clinical presentation of the organizing pneumonias caused by COVID-19 as well as other viral infections. We also use the clinical efficacy of corticosteroids in other postinfection OPs (PIOPs) to predict the therapeutic response in the treatment of PCOP. Finally, we discuss the potential application of a candidate anti-inflammatory and antifibrotic therapy for the treatment of PCOP based on the analysis of the latest clinical trials data.

CD147 contributes to SARS-CoV-2-induced pulmonary fibrosis

COVID-19 patients can develop clinical and histopathological features associated with fibrosis, but the pathogenesis of fibrosis remains poorly understood. CD147 has been identified as a universal receptor for SARS-CoV-2 and its variants, which could initiate COVID-19-related cytokine storm. Here, we systemically analyzed lung pathogenesis in SARS-CoV-2- and its delta variant-infected humanized CD147 transgenic mice. Histopathology and Transmission Electron Microscopy revealed inflammation, fibroblast expansion and pronounced fibrotic remodeling in SARS-CoV-2-infected lungs. Consistently, RNA-sequencing identified a set of fibrosis signature genes. Furthermore, we identified CD147 as a crucial regulator for fibroblast activation induced by SARS-CoV-2. We found conditional knockout of CD147 in fibroblast suppressed activation of fibroblasts, decreasing susceptibility to bleomycin-induced pulmonary fibrosis. Meplazumab, a CD147 antibody, was able to inhibit the accumulation of activated fibroblasts and the production of ECM proteins, thus alleviating the progression of pulmonary fibrosis caused by SARS-CoV-2. In conclusion, we demonstrated that CD147 contributed to SARS-CoV-2-triggered progressive pulmonary fibrosis and identified CD147 as a potential therapeutic target for treating patients with post-COVID-19 pulmonary fibrosis.

Pathophysiological conditions induced by SARS-CoV-2 infection reduce ACE2 expression in the lung

SARS-CoV-2 infection causes a variety of physiological responses in the lung, and understanding how the expression of SARS-CoV-2 receptor, angiotensin-converting enzyme 2 (ACE2), and its proteolytic activator, transmembrane serine protease 2 (TMPRSS2), are affected in patients with underlying disease such as interstitial pneumonia will be important in considering COVID-19 progression. We examined the expression of ACE2 and TMPRSS2 in an induced usual interstitial pneumonia (iUIP) mouse model and patients with IPF as well as the changes in whole-lung ACE2 and TMPRSS2 expression under physiological conditions caused by viral infection. Histopathological and biochemical characteristics were analyzed using human specimens from patients with IPF and precision-cut lung slices (PCLS) from iUIP mouse model showing UIP with honeycombing and severe fibrosis after non-specific interstitial pneumonia. ACE2 expression decreased with acute lung inflammation and increased in the abnormal lung epithelium of the iUIP mouse model. ACE2 is also expressed in metaplastic epithelial cells. Poly(I:C), interferons, and cytokines associated with fibrosis decreased ACE2 expression in PCLS in the iUIP model. Hypoxia also decreases ACE2 via HIF1α in PCLS. Antifibrotic agent, nintedanib attenuates ACE2 expression in invasive epithelial cells. Patients with IPF are at a higher risk of SARS-CoV-2 infection due to the high expression of ACE2. However, ACE2 and TMPRSS2 expression is decreased by immune intermediaries, including interferons and cytokines that are associated with viral infection and upon administration of antifibrotic agents, suggesting that most of the viral infection-induced pathophysiological responses aid the development of resistance against SARS-CoV-2 infection.

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

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

The Effect of Nintedanib in Post-COVID-19 Lung Fibrosis: An Observational Study

Background

Lung fibrosis is a sequela of COVID-19 among patients with severe pneumonia. Idiopathic pulmonary fibrosis and lung fibrosis due to COVID-19 may share many similar features. There are limited data on effects of antifibrotic treatment of infection-related lung fibrosis. This study aimed to evaluate the effect of nintedanib on patients' post-COVID-19 lung fibrosis.

Methods

A retrospective, matched case-control study was performed on hospitalized patients with COVID-19 pneumonia. Patients who received nintedanib treatment for COVID-19 pulmonary fibrosis (nintedanib group) were compared to patients with standard treatment (control group). The primary outcome was oxygen improvement. The secondary outcomes were chest X-ray improvement, SpO₂/FiO₂ ratio improvement, mortality rates at 60 days, and adverse events.

Results

A total of 42 patients with COVID-19 pneumonia were included (21 in each group). Mean age was 64.43 ± 14.59 years, and 54.8% were men. At baseline, SpO₂/FiO₂ ratio before treatment was 200.57 ± 105.77 in the nintedanib group and 326.90 ± 137.10 in the control group (P = 0.002). Oxygen improvement and chest X-ray improvement were found in 71.4% and 71.4% in the nintedanib group and in 66.7% and 66.7% in the control group (P = 0.739). The nintedanib group had more improvement in SpO₂/FiO₂ ratio than in the control group (144.38 ± 118.05 vs 55.67 ± 75.09, P = 0.006). The 60-day mortality rates of the nintedanib and the control groups were 38.1% vs 23.8%, P = 0.317. Hepatitis and loss of appetite were common adverse events (9.5% and 9.5%), while the incidence of diarrhea was 4.8%.

Conclusions

Nintedanib as add-on treatment in post-COVID-19 lung fibrosis did not improve oxygenation, chest X-ray findings, or the 60-day mortality. However, this antifibrotic drug improved SpO₂/FiO₂ ratio in our patients. Further randomized controlled trials are needed to determine the efficacy of nintedanib for treatment of patients with post-COVID-19 lung fibrosis. Trial Registration. This study was registered in TCTR20220426001.

Virtual screening and activity evaluation of multitargeting inhibitors for idiopathic pulmonary fibrosis

Transforming growth factor β receptor (TGF-β1R) and receptor tyrosine kinases (RTKs), such as VEGFRs, PDGFRs and FGFRs are considered important therapeutic targets in blocking myofibroblast migration and activation of idiopathic pulmonary fibrosis (IPF). To screen and design innovative prodrug to simultaneously target these four classes of receptors, we proposed an approach based on network pharmacology combining virtual screening and machine learning activity prediction, followed by efficient in vitro and in vivo models to evaluate drug activity. We first constructed Collagen1A2-A549 cells with type I collagen as the main biomarker and evaluated the activity of compounds to inhibit collagen expression at the cellular level. The data from the first round of Collagen1A2-A549 cell screening were substituted into the machine learning model, and the model was optimized accordingly. As a result, the false positive rate of the model was reduced from 85.0% to 66.7%, and two prospective compounds, Z103080500 and Z104578368, were finally selected. Collagen levels were reduced effectively by both Z103080500 (67.88% reduction) and Z104578368 (69.54% reduction). Moreover, these two compounds showed low cellular cytotoxicity. Subsequently, the effect of Z103080500 and Z104578368 was evaluated in a bleomycin-induced C57BL/6 mouse IPF model. These results showed that 50 mg/kg Z103080500 and Z104578368 could effectively reduce the number of inflammatory cells and the expression level of α-SMA. Meanwhile, Z103080500 and Z104578368 reduced the expression of major markers and inflammatory factors of IPF, such as collagen, IFN-γ, IL-17 and HYP, indicating that these screened Z103080500 and Z104578368 effectively delayed lung tissue inflammation and had a potential therapeutic effect on IPF. Our findings demonstrate that a screening and evaluation model for prodrug against IPF has been successfully established. It is of great significance to further modify these compounds to enhance their potency and activity.

Pathophysiology of Pulmonary Fibrosis in the Context of COVID-19 and Implications for Treatment: A Narrative Review

Pulmonary fibrosis (PF) is a feared outcome of many pulmonary diseases which results in a reduction in lung compliance and capacity. The development of PF is relatively rare, but it can occur secondary to viral pneumonia, especially COVID-19 infection. While COVID-19 infection and its complications are still under investigation, we can look at a similar outbreak in the past to gain better insight as to the expected long-term outcomes of COVID-19 patient lung function. In the current article, we review the literature relative to PF via PubMed. We also performed a literature search for COVID-related pathological changes in the lungs. Finally, the paper was reviewed and summarized based on the studies’ integrity, relative, or power calculations. This article provides a narrative review that endeavors to elucidate the current understanding of the pathophysiological mechanisms underlying PF and therapeutic strategies. We also discussed the potential for preventing progression to the fibrotic state within the context of the COVID-19 pandemic. With the massive scale of the COVID-19 pandemic, we expect there should more instances of PF due to COVID-19 infection. Patients who survive severe COVID-19 infection may suffer from a high incidence of PF.

COVID-19-Associated Lung Fibrosis: Two Pathways and Two Phenotypes, Lung Transplantation, and Antifibrotics

COVID-19 can be associated with lung fibrosis. Although lung fibrosis after COVID-19 is a relatively rare finding, the mere fact that globally a very large number of patients have had COVID-19 leads to a significant burden of disease. However, patients with COVID-19-associated lung fibrosis have different clinical and radiological features. The aim of this review is to define the different phenotypes of COVID-19-associated lung fibrosis, based on the medical literature. We found that two phenotypes have emerged. One phenotype is COVID-19-related acute respiratory distress syndrome (CARDS); the other phenotype is post-COVID-19 pulmonary fibrosis (PCPF). Both phenotypes have different risk factors, clinical, and radiological features, and differ in their pathophysiological mechanisms and prognoses. A long-term follow-up of patients with pulmonary complications after COVID-19 is warranted, even in patients with only discrete fibrosis. Further studies are needed to determine the optimal treatment because currently the literature is scarce, and evidence is only based on small case series or case reports.

Post-Coronavirus Disease 2019 Pulmonary Fibrosis: Wait or Needs Intervention

Coronavirus disease 2019 (COVID-19) has become a major health burden worldwide, with over 450 million confirmed cases and 6 million deaths. Although the acute phase of COVID-19 management has been established, there is still a long way to go to evaluate the long-term clinical course or manage complications due to the relatively short outbreak of the virus. Pulmonary fibrosis is one of the most common respiratory complications associated with COVID-19. Scarring throughout the lungs after viral or bacterial pulmonary infection have been commonly observed, but the prevalence of post-COVID-19 pulmonary fibrosis is rapidly increasing. However, there is limited information available about post-COVID-19 pulmonary fibrosis, and there is also a lack of consensus on what condition should be defined as post-COVID-19 pulmonary fibrosis. During a relatively short follow-up period of approximately 1 year, lesions considered related to pulmonary fibrosis often showed gradual improvement; therefore, it is questionable at what time point fibrosis should be evaluated. In this review, we investigated the epidemiology, risk factors, pathogenesis, and management of post-COVID-19 pulmonary fibrosis.

A systems biology approach identifies candidate drugs to reduce mortality in severely ill patients with COVID-19

Despite the availability of highly efficacious vaccines, coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lacks effective drug treatment, which results in a high rate of mortality. To address this therapeutic shortcoming, we applied a systems biology approach to the study of patients hospitalized with severe COVID. We show that, at the time of hospital admission, patients who were equivalent on the clinical ordinal scale displayed significant differential monocyte epigenetic and transcriptomic attributes between those who would survive and those who would succumb to COVID-19. We identified messenger RNA metabolism, RNA splicing, and interferon signaling pathways as key host responses overactivated by patients who would not survive. Those pathways are prime drug targets to reduce mortality of critically ill patients with COVID-19, leading us to identify tacrolimus, zotatifin, and nintedanib as three strong candidates for treatment of severely ill patients at the time of hospital admission.

Newly Emerged Antiviral Strategies for SARS-CoV-2: From Deciphering Viral Protein Structural Function to the Development of Vaccines, Antibodies, and Small Molecules

Coronavirus disease 2019 (COVID-19) caused by the infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become the most severe health crisis, causing extraordinary economic disruption worldwide. SARS-CoV-2 is a single-stranded RNA-enveloped virus. The process of viral replication and particle packaging is finished in host cells. Viral proteins, including both structural and nonstructural proteins, play important roles in the viral life cycle, which also provides the targets of treatment. Therefore, a better understanding of the structural function of virus proteins is crucial to speed up the development of vaccines and therapeutic strategies. Currently, the structure and function of proteins encoded by the SARS-CoV-2 genome are reviewed by several studies. However, most of them are based on the analysis of SARS-CoV-1 particles, lacking a systematic review update for SARS-CoV-2. Here, we specifically focus on the structure and function of proteins encoded by SARS-CoV-2. Viral proteins that contribute to COVID-19 infection and disease pathogenesis are reviewed according to the most recent research findings. The structure-function correlation of viral proteins provides a fundamental rationale for vaccine development and targeted therapy. Then, current antiviral vaccines are updated, such as inactive viral vaccines and protein-based vaccines and DNA, mRNA, and circular RNA vaccines. A summary of other therapeutic options is also reviewed, including monoclonal antibodies such as a cross-neutralizer antibody, a constructed cobinding antibody, a dual functional monoclonal antibody, an antibody cocktail, and an engineered bispecific antibody, as well as peptide-based inhibitors, chemical compounds, and clustered regularly interspaced short palindromic repeats (CRISPR) exploration. Overall, viral proteins and their functions provide the basis for targeted therapy and vaccine development.

Post-COVID Syndrome: The Research Progress in the Treatment of Pulmonary sequelae after COVID-19 Infection

Post-COVID syndrome or long COVID is defined as the persistence of symptoms after confirmed SARS-CoV-2 infection, the pathogen responsible for coronavirus disease. The content herein presented reviews the reported long-term consequences and aftereffects of COVID-19 infection and the potential strategies to adopt for their management. Recent studies have shown that severe forms of COVID-19 can progress into acute respiratory distress syndrome (ARDS), a predisposing factor of pulmonary fibrosis that can irreversibly compromise respiratory function. Considering that the most serious complications are observed in the airways, the inhalation delivery of drugs directly to the lungs should be preferred, since it allows to lower the dose and systemic side effects. Although further studies are needed to optimize these techniques, recent studies have also shown the importance of in vitro models to recreate the SARS-CoV-2 infection and study its sequelae. The information reported suggests the necessity to develop new inhalation therapies in order to improve the quality of life of patients who suffer from this condition.

Indole-Based Small Molecules as Potential Therapeutic Agents for the Treatment of Fibrosis

Indole alkaloids are widely distributed in nature and have been particularly studied because of their diverse biological activities, such as anti-inflammatory, anti-tumor, anti-bacterial, and anti-oxidant activities. Many kinds of indole alkaloids have been applied to clinical practice, proving that indole alkaloids are beneficial scaffolds and occupy a crucial position in the development of novel agents. Fibrosis is an end-stage pathological condition of most chronic inflammatory diseases and is characterized by excessive deposition of fibrous connective tissue components, ultimately resulting in organ dysfunction and even failure with significant morbidity and mortality. Indole alkaloids and indole derivatives can alleviate pulmonary, myocardial, renal, liver, and islet fibrosis through the suppression of inflammatory response, oxidative stress, TGF-β/Smad pathway, and other signaling pathways. Natural indole alkaloids, such as isorhynchophylline, evodiamine, conophylline, indirubin, rutaecarpine, yohimbine, and vincristine, are reportedly effective in organ fibrosis treatment. In brief, indole alkaloids with a wide range of pharmacological bioactivities are important candidate drugs for organ fibrosis treatment. The present review discusses the potential of natural indole alkaloids, semi-synthetic indole alkaloids, synthetic indole derivatives, and indole-contained metabolites in organ fibrosis treatment.

Mineralocorticoid Receptor Antagonist (Potassium Canrenoate) Does Not Influence Outcome in the Treatment of COVID-19-Associated Pneumonia and Fibrosis—A Randomized Placebo Controlled Clinical Trial

In December 2019 the SARS-CoV-2 virus appeared in the world, mainly presenting as an acute infection of the lower respiratory tract, namely pneumonia. Nearly 10% of all patients show significant pulmonary fibrotic changes after the infection. The aim of this study was to evaluate the effectiveness and safety of potassium canrenoate in the treatment of COVID-19-associated pneumonia and pulmonary fibrosis. We performed a randomized clinical trial (RCT) of potassium canrenoate vs placebo. A total of 55 patients were randomized and 49 were included in the final analysis (24 allocated to the intervention group and 25 allocated to the control group). Patients were assessed by physical examination, lung ultrasound, CT imaging and blood samples that underwent biochemical analysis. This RCT has shown that the administration of potassium canrenoate to patients with COVID-19 induced pneumonia was not associated with shorter mechanical ventilation time, shorter passive oxygenation, shorter length of hospitalization or less fibrotic changes on CT imaging. The overall mortality rate was not significantly different between the two groups. Adverse events recorded in this study were not significantly increased by the administration of potassium canrenoate. The negative outcome of the study may be associated with the relatively small number of patients included. Any possible benefits from the use of potassium canrenoate as an antifibrotic drug in COVID-19 patients require further investigation.

Pharmaco-immunomodulatory interventions for averting cytokine storm-linked disease severity in SARS-CoV-2 infection

The year 2020 is characterised by the COVID-19 pandemic that has quelled more than half a million lives in recent months. We are still coping with the negative repercussions of COVID-19 pandemic in 2021, in which the 2nd wave in India resulted in a high fatality rate. Regardless of emergency vaccine approvals and subsequent meteoric global vaccination drives in some countries, hospitalisations for COVID-19 will continue to occur due to the propensity of mutation in SARS-CoV-2 virus. The immune response plays a vital role in the control and resolution of infectious diseases. However, an impaired immune response is responsible for the severity of the respiratory distress in many diseases. The severe COVID-19 infection persuaded cytokine storm that has been linked with acute respiratory distress syndrome (ARDS), culminates into vital organ failures and eventual death. Thus, safe and effective therapeutics to treat hospitalised patients remains a significant unmet clinical need. In that state, any clue of possible treatments, which save patients life, can be treasured for this time point. Many cohorts and clinical trial studies demonstrated that timely administration of immunomodulatory drugs on severe COVID-19 patients may mitigate the disease severity, hospital stay and mortality. This article addresses the severity and risk factors of hypercytokinemia in COVID-19 patients, with special emphasis on prospective immunomodulatory therapies.

Time-Dependent Molecular Motifs of Pulmonary Fibrogenesis in COVID-19

(1) Background: In COVID-19 survivors there is an increased prevalence of pulmonary fibrosis of which the underlying molecular mechanisms are poorly understood; (2) Methods: In this multicentric study, n = 12 patients who succumbed to COVID-19 due to progressive respiratory failure were assigned to an early and late group (death within ≤7 and >7 days of hospitalization, respectively) and compared to n = 11 healthy controls; mRNA and protein expression as well as biological pathway analysis were performed to gain insights into the evolution of pulmonary fibrogenesis in COVID-19; (3) Results: Median duration of hospitalization until death was 3 (IQR25-75, 3–3.75) and 14 (12.5–14) days in the early and late group, respectively. Fifty-eight out of 770 analyzed genes showed a significantly altered expression signature in COVID-19 compared to controls in a time-dependent manner. The entire study group showed an increased expression of BST2 and IL1R1, independent of hospitalization time. In the early group there was increased activity of inflammation-related genes and pathways, while fibrosis-related genes (particularly PDGFRB) and pathways dominated in the late group; (4) Conclusions: After the first week of hospitalization, there is a shift from pro-inflammatory to fibrogenic activity in severe COVID-19. IL1R1 and PDGFRB may serve as potential therapeutic targets in future studies.

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.