Recovering from a pandemic: pulmonary fibrosis after SARS-CoV-2 infection

Hesperidin alleviates pulmonary fibrosis by regulating EI24-mediated autophagy

BACKGROUND

Etoposide-induced protein 2.4 (EI24), an essential component of autophagy, is lowly expressed in pulmonary fibrosis. Hesperidin (Hes), a flavonoid, can regulate autophagy in various diseases. However, whether Hes can inhibit pulmonary fibrosis by mechanically regulating EI24-mediated autophagy has not been uncovered.

METHODS

RLE-6TN cells were treated with transforming growth factor β1 (TGF-β1) and rats were injected with bleomycin (BLM) to construct the pulmonary fibrosis model. The effect of Hes on pulmonary fibrosis was evaluated by cell counting kit-8, immunofluorescence, hematoxylin and eosin, masson trichome staining and western blotting.

RESULTS

Hes reduced cell viability of TGF-β1-induced RLE-6TN cells. Administration of Hes restored the decrease in autophagy marker levels in TGF-β1-induced RLE-6TN cells. Hes inhibited the transcriptional and translational levels of α-SMA, collagen I and fibronectin that were increased by TGF-β1 in RLE-6TN cells. Mechanically, Hes restored EI24 expression, and EI24 knockdown reversed the effect of Hes on the expressions of autophagy and fibrosis-related proteins. Additionally, Hes enhanced autophagy and fibrosis markers, which were worsened by EI24 knockdown in BLM-induced rats.

CONCLUSION

Hes activated autophagy by upregulating EI24, which improved pulmonary fibrosis both in vitro and in vivo.

Challenges and Opportunities for Post-COVID Pulmonary Disease: A Focused Review of Immunomodulation

The resolution of the recent COVID-19 pandemic still requires attention, since the consequences of having suffered the infection, even in mild cases, are associated with several acute and chronic pathological conditions referred to as post-COVID syndrome (PCS). PCS often manifests with pulmonary disease and, in up to 9% of cases, a more serious complication known as post-COVID-19 pulmonary fibrosis (PC19-PF), which has a similar clinical course as idiopathic pulmonary fibrosis (IPF). Generating knowledge to provide robust evidence about the clinical benefits of different therapeutic strategies to treat the pulmonary effects of PCS can provide new insights to amplify therapeutic options for these patients. We present evidence found after a scoping review, following extended PRIMSA guidelines, for the use of immunomodulators in pulmonary PCS. We start with a brief description of the immunomodulatory properties of the relevant drugs, their clinically proven efficacy for viral infections and chronic inflammatory conditions, and their use during the COVID-19 pandemic. We emphasize the need for well-designed clinical trials to improve our understanding the physiopathology of pulmonary PCS and PC19-PF and also to determine the efficacy and safety of candidate treatments.

Early nintedanib deployment in COVID-19 interstitial lung disease (ENDCOV-I): study protocol of a randomised, double-blind, placebo-controlled trial

INTRODUCTION

In December 2019, the novel SARS-CoV-2 triggered a global pneumonia outbreak, leading to millions of deaths worldwide. A subset of survivors faces increased morbidity and mortality, particularly due to subacute lung injury evolving to chronic fibrosing interstitial lung disease. While nintedanib, a tyrosine-kinase inhibitor, shows promise in treating progressive fibrotic lung disease, limited randomised trial data exists for post-COVID-19-induced lung injury. We hypothesise that treatment with nintedanib may attenuate advancement to the fibrotic stages, offering a potential avenue for improving outcomes in this specific patient subset.

METHODS AND ANALYSIS

We describe the design of a multicentre, randomised, double-blind, placebo-controlled trial involving approximately 170 patients with subacute lung injury secondary to COVID-19, who required respiratory support with oxygen supplementation. Patients are randomised by site and disease phenotype (fibrotic vs non-fibrotic) in a 1:1 ratio to either oral nintedanib or placebo. Patients will be followed for 180 days. The primary endpoint is to assess change from baseline in forced vital capacity (FVC, mL) at 180 days. Secondary objectives include change in FVC (mL) at 90 days; diffusing capacity of carbon monoxide (% of predicted) and 6-min walk test (feet) at 180 days; and mortality at 90 and 180 days. Qualitative and quantitative changes in high-resolution computerised tomography (HRCT), change in patient-reported outcome measures (PROMs) and safety endpoints will also be assessed. Analysis will be performed according to the intention-to-treat principle.

ETHICS AND DISSEMINATION

The study is conducted in accordance with the Good Clinical Practices as outlined by the Food and Drug Administration and the Declaration of Helsinki 2008. This study received approval from participating sites' Institutional Review Boards and committees, including The Ethics Committee of the Medical Board at the Mount Sinai Hospital (ID: HS#20-01166). The Independent Oversight Committee oversees study conduct, data and patient safety for the duration of the study investigation. The trial details presented align with the trial protocol V.8. (April 2022). Results will be presented at national and international conferences, published in a peer-reviewed journal and disseminated to patients, funders and researchers on data analysis completion.

TRIAL REGISTRATION NUMBER

NCT04619680. First posted 6 November 2020.

Insights into Long COVID: Unraveling Risk Factors, Clinical Features, Radiological Findings, Functional Sequelae and Correlations: A Retrospective Cohort Study

BACKGROUND

The long-term symptomatology of COVID-19 has yet to be comprehensively described. The aim of the study was to describe persistent COVID-19 symptoms in a cohort of hospitalized and home-isolated patients.

METHODS

A retrospective cohort study was conducted on long COVID patients. Long COVID symptoms were identified, and patients were divided into hospitalized (in-patients) and home-isolated (out-patients), as well as according to the number of symptoms. Patients were examined by a multidisciplinary medical team. Blood tests, high resolution chest computed tomography (CT), and physical and infectious examinations were performed. Finally, in-patients were evaluated at 2 time-points: on hospital admission (T0) and 3 months after discharge (Tpost).

RESULTS

There were 364 COVID-19 patients enrolled; 82% of patients reported one or more symptoms. The most reported symptom was fatigue. Chest CT showed alteration in 76% of patients, and pulmonary function alterations were observed in 44.7% of patients. A higher risk of presenting at least one symptom was seen in patients treated with corticosteroid, and a higher risk of presenting chest CT residual lesion was observed in hospitalized patients and in patients that received hydroxychloroquine treatment. Moreover, a higher risk of altered pulmonary function was observed in older patients.

CONCLUSION

Long-term sequelae are present in a remarkable number of long COVID patients and pose a new challenge to the health care system to identify long-lasting effects and improve patients' well-being. Multidisciplinary teams are crucial to develop preventive measures, and clinical management strategies.

Alveolar epithelial type 2 cell specific loss of IGFBP2 activates inflammation in COVID-19

The coronavirus disease 2019 (COVID-19) global pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, our understanding of SARS-CoV-2-induced inflammation in alveolar epithelial cells remains very limited. The contributions of intracellular insulin-like growth factor binding protein-2 (IGFBP2) to SARS-CoV-2 pathogenesis are also unclear. In this study, we have uncovered a critical role for IGFBP2, specifically in alveolar epithelial type 2 cells (AEC2), in the immunopathogenesis of COVID-19. Using bulk RNA sequencing, we show that IGFBP2 mRNA expression is significantly downregulated in primary AEC2 cells isolated from fibrotic lung regions from patients with COVID-19-acute respiratory distress syndrome (ARDS) compared to those with idiopathic pulmonary fibrosis (IPF) alone or IPF with a history of COVID-19. Using multicolor immunohistochemistry, we demonstrated that IGFBP2 and its selective ligands IGF1 and IGF2 were significantly reduced in AEC2 cells from patients with COVID-ARDS, IPF alone, or IPF with COVID history than in those from age-matched donor controls. Further, we demonstrated that lentiviral expression of Igfbp2 significantly reduced mRNA expression of proinflammatory cytokines-Tnf-α, Il1β, Il6, Stat3, Stat6 and chemokine receptors-Ccr2 and Ccr5-in mouse lung epithelial cells challenged with SARS-CoV-2 spike protein injury (S2; 500 ng/mL). Finally, we demonstrated higher levels of cytokines-TNF-α; IL-6 and chemokine receptor-CCR5 in AEC2 cells from COVID-ARDS patients compared to the IPF alone and the IPF with COVID history patients. Altogether, these data suggest that anti-inflammatory properties of IGFBP2 in AEC2 cells and its localized delivery may serve as potential therapeutic strategy for patients with COVID-19.

Novel insights into the ROCK-JAK-STAT signaling pathway in upper respiratory tract infections and neurodegenerative diseases

Acute upper respiratory tract infections are a major public health issue, with uncontrolled inflammation triggered by upper respiratory viruses being a significant cause of patient deterioration or death. This study focuses on the Janus kinase-signal transducer and activator of transcription Rho-associated coiled-coil containing protein kinase (JAK-STAT-ROCK) signaling pathway, providing an in-depth analysis of the interplay between uncontrolled inflammation after upper respiratory tract infections and the development of neurodegenerative diseases. It offers a conceptual framework for understanding the lung-brain-related immune responses and potential interactions. The relationship between the ROCK-JAK-STAT signaling pathway and inflammatory immunity is a complex and multi-layered research area and exploring potential common targets could open new avenues for the prevention and treatment of related inflammation.

MicroRNA-guided drug discovery for mitigating persistent pulmonary complications in critical COVID-19 survivors: A longitudinal pilot study

BACKGROUND AND PURPOSE

The post-acute sequelae of SARS-CoV-2 infection pose a significant global challenge, with nearly 50% of critical COVID-19 survivors manifesting persistent lung abnormalities. The lack of understanding about the molecular mechanisms and effective treatments hampers their management. Here, we employed microRNA (miRNA) profiling to decipher the systemic molecular underpinnings of the persistent pulmonary complications.

EXPERIMENTAL APPROACH

We conducted a longitudinal investigation including 119 critical COVID-19 survivors. A comprehensive pulmonary evaluation was performed in the short-term (median = 94.0 days after hospital discharge) and long-term (median = 358 days after hospital discharge). Plasma miRNAs were quantified at the short-term evaluation using the gold-standard technique, RT-qPCR. The analyses combined machine learning feature selection techniques with bioinformatic investigations. Two additional datasets were incorporated for validation.

KEY RESULTS

In the short-term, 84% of the survivors exhibited impaired lung diffusion (DLCO < 80% of predicted). One year post-discharge, 54.4% of this patient subgroup still presented abnormal DLCO. Four feature selection methods identified two specific miRNAs, miR-9-5p and miR-486-5p, linked to persistent lung dysfunction. The downstream experimentally validated targetome included 1473 genes, with heterogeneous enriched pathways associated with inflammation, angiogenesis and cell senescence. Validation studies using RNA-sequencing and proteomic datasets emphasized the pivotal roles of cell migration and tissue repair in persistent lung dysfunction. The repositioning potential of the miRNA targets was limited.

CONCLUSION AND IMPLICATIONS

Our study reveals early mechanistic pathways contributing to persistent lung dysfunction in critical COVID-19 survivors, offering a promising approach for the development of targeted disease-modifying agents.

LINKED ARTICLES

This article is part of a themed issue Non-coding RNA Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.2/issuetoc.

Multidisciplinary Center Care for Long COVID Syndrome-A Retrospective Cohort Study

BACKGROUND

Persistent multi-organ symptoms after coronavirus disease 2019 (COVID-19) have been termed "long COVID" or "post-acute sequelae of SARS-CoV-2 infection." The complexity of these clinical manifestations posed challenges early in the pandemic as different ambulatory models formed out of necessity to manage the influx of patients. Little is known about the characteristics and outcomes of patients seeking care at multidisciplinary post-COVID centers.

METHODS

We performed a retrospective cohort study of patients evaluated at our multidisciplinary comprehensive COVID-19 center in Chicago, Ill, between May 2020 and February 2022. We analyzed specialty clinic utilization and clinical test results according to severity of acute COVID-19.

RESULTS

We evaluated 1802 patients a median of 8 months from acute COVID-19 onset, including 350 post-hospitalization and 1452 non-hospitalized patients. Patients were seen in 2361 initial visits in 12 specialty clinics, with 1151 (48.8%) in neurology, 591 (25%) in pulmonology, and 284 (12%) in cardiology. Among the patients tested, 742/916 (81%) reported decreased quality of life, 284/553 (51%) had cognitive impairment, 195/434 (44.9%) had alteration of lung function, 249/299 (83.3%) had abnormal computed tomography chest scans, and 14/116 (12.1%) had elevated heart rate on rhythm monitoring. Frequency of cognitive impairment and pulmonary dysfunction was associated with severity of acute COVID-19. Non-hospitalized patients with positive SARS-CoV-2 testing had findings similar to those with negative or no test results.

CONCLUSIONS

The experience at our multidisciplinary comprehensive COVID-19 center shows common utilization of multiple specialists by long COVID patients, who harbor frequent neurologic, pulmonary, and cardiologic abnormalities. Differences in post-hospitalization and non-hospitalized groups suggest distinct pathogenic mechanisms of long COVID in these populations.

Long COVID among the first three waves of COVID-19 in Japan: a multicentre cohort study

OBJECTIVES

Severe acute respiratory syndrome coronavirus 2 significantly impacts Japan with a high number of infections and deaths reported. Long coronavirus disease (COVID) characterised by persistent symptoms after COVID-19 has gained recognition but varies across studies. This study aimed to investigate the differences in long COVID among patients hospitalised during Japan's first three waves of the pandemic.

DESIGN

Multicentre prospective cohort study.

SETTING

26 medical facilities across Japan between February 2020 and February 2021.

PARTICIPANTS

In total, 1066 hospitalised patients diagnosed with COVID-19 were included with 206, 301 and 559 patients in the first, second and third waves, respectively. Data were collected using electronic data capture and patient-reported outcome forms.

PRIMARY AND SECONDARY OUTCOME MEASURES

Long COVID was assessed at 3, 6 and 12 months after COVID-19 diagnosis.

RESULTS

Significant differences were observed between the waves in various baseline and clinical characteristics such as age, body mass index (BMI), comorbidities, the severity of COVID-19, complications and treatment during hospitalisation. Long COVID, particularly dyspnoea, was most prevalent in the first wave. Multivariate logistic regression analysis confirmed a significant positive association between the first wave and long COVID including dyspnoea after adjusting for age, sex, BMI, smoking status and COVID-19 severity.

CONCLUSIONS

Patients hospitalised during the first wave had a higher risk of experiencing long COVID, especially dyspnoea, than those hospitalised during the other waves. These findings underscore the need for continued monitoring and managing long COVID in COVID-19 survivors, particularly in those hospitalised during the first wave.

TRIAL REGISTRATION NUMBER

UMIN000042299.

Effects of acute-phase COVID-19-related indicators on pulmonary fibrosis and follow-up evaluation

BACKGROUND

Post-COVID-19 pulmonary fibrosis is a significant long-term respiratory morbidity affecting patients' respiratory health. This exploratory study aims to investigate the incidence, clinical characteristics, and acute-phase risk factors for pulmonary fibrosis in COVID-19 patients. Additionally, it evaluates pulmonary function and chest CT outcomes to provide clinical evidence for the early identification of high-risk patients and the prevention of post-COVID-19 pulmonary fibrosis.

METHODS

We retrospectively analyzed 595 patients hospitalized for COVID-19 from January 2022 to July 2023. Patients were divided into fibrosis and nonfibrosis groups on the basis of imaging changes. Baseline data, including demographics, disease severity, laboratory indicators, and chest imaging characteristics, were collected. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors for pulmonary fibrosis. Pulmonary function and chest CT follow-ups were conducted for the fibrosis group. The data were processed via SPSS 26.0, with P < 0.05 considered statistically significant.

RESULTS

The incidence of pulmonary fibrosis was 4.37%, with 2.08% in moderate cases and 8.22% in severe cases. Significant differences were found between the fibrosis and nonfibrosis groups in sex; disease severity; NLR; ALB and LDH levels; and percentages of lung reticular lesions, consolidations, and GGOs (P < 0.05). Multivariate analysis revealed LDH (OR = 1.004, 95% CI 1.000-1.007, P = 0.035), ALB (OR = 0.871, 95% CI 0.778-0.974, P = 0.015), lung reticular lesion volume (OR = 1.116, 95% CI 1.040-1.199, P = 0.002), and lung consolidation volume (OR = 1.131, 95% CI 1.012-1.264, P = 0.030) as independent risk factors. The follow-up results revealed significant improvements in pulmonary function, specifically in the FVC%, FEV1%, and DLCO%, but not in the FEV1/FVC. Quantitative chest CT analysis revealed significant differences in lung reticular lesions, consolidation, and GGO volumes but no significant difference in honeycomb volume.

CONCLUSIONS

The incidence of pulmonary fibrosis post-COVID-19 increases with disease severity. LDH, ALB, lung reticular lesions, and consolidation volume are independent risk factors for patients with fibrosis.

Prolonged corticosteroid therapy and lung abnormalities in patients after severe COVID-19 pneumonia

BACKGROUND

Some of the hospitalized patients after severe COVID-19 pneumonia experience significant fall in peripheral saturation despite optimal treatment. Because of immune dysregulation in COVID-19 there are indications that prolonged corticosteroids could be considered in treating patients for persistent radiological sequelae and respiratory symptoms.

OBJECTIVES

to investigate lung function and lung sequelae on high-resolution CT (HRCT) im COVID-19 patients who were treated with glucocorticoid therapy in two dose regimens with a control group of patients who did not receive additional glucocorticoid therapy.

METHODS

In this prospective cohort research we studied patients who suffered from prolonged respiratory insufficiency after severe COVID-19 pneumonia. Patients received corticosteroid therapy in two dose regimens: for 14 days and for 3 months after discharge from the hospital. Control group of patients did not receive additional corticosteroid therapy. Lung function, post-COVID-19 symptoms, and lung abnormalities on CT scans were analyzed in three months follow-up and compared with the control group of patients.

RESULTS

Patients who received prolonged corticosteroid therapy for three months did not have better CT findings of lung abnormalities, lung function, or symptoms recovery in comparison to the patients with 14 days of therapy and control group of patients. Onwards, control group had significantly fewer dyspnea symptoms (Chi-square test, p=0,04) and higher DLCO (Kruskal Wallis test, p=0,03).

CONCLUSIONS

Supplementary corticosteroid therapy for patients after severe pneumonia and prolonged respiratory insufficiency with lung abnormalities after COVID-19 did not improve lung function or lung lesions on CT.

Comparison of methotrexate and methylprednisolone as addition to antifibrotic therapy in progressive pulmonary fibrosis due to COVID-19

BACKGROUND

Post-covid pulmonary fibrosis (PCPF) is an essential cause of hypoxic respiratory failure, especially in patients with severe COVID-19 infection. In our study, we aimed to compare the effectiveness of methylprednisolone and methotrexate treatments in patients diagnosed with PCPF and in whom progression was observed despite nintedanib treatment.  Methods: Forty-eight patients diagnosed with PCPF between April 2022 and February 2023 were followed up in our study. Progressive pulmonary fibrosis was observed in 18 of these patients despite nintedanib treatment. Nintedanib + methylprednisolone treatment was started in Group 1 patients, and nintedanib + methotrexate treatment was started in Group 2 patients, and after three months, a respiratory function test (PFT), 6-minute walk test (6MWT), saturation, pulse, and side effect levels were compared.

RESULTS

In comparing the groups at the end of the 3rd month, the change in PFT parameters was higher in Group 2 patients than in Group 1 patients. However, there was no statistically significant difference. However, the increase in fingertip saturation, 6MWT levels, and decrease in pulse levels were statistically significantly different in Group 2 patients compared to Group 1 patients (p=0.001 for all).  It was observed that complaints of muscle and joint pain, weight gain, and atrophy in peripheral extremities in Group 1 patients were statistically significantly higher than in Group 2 patients (p=0.001, 0.002, 0.001, respectively).

CONCLUSION

Methotrexate can be used as an alternative to methylprednisolone in PCPF due to its low side effect profile and its effectiveness in PFT, 6MWT, and saturation levels.

Emerging concepts in mucosal immunity and oral microecological control of respiratory virus infection-related inflammatory diseases

Oral microecological imbalance is closely linked to oral mucosal inflammation and is implicated in the development of both local and systemic diseases, including those caused by viral infections. This review examines the critical role of the interleukin (IL)-17/helper T cell 17 (Th17) axis in regulating immune responses within the oral mucosa, focusing on both its protective and pathogenic roles during inflammation. We specifically highlight how the IL-17/Th17 pathway contributes to dysregulated inflammation in the context of respiratory viral infections. Furthermore, this review explores the potential interactions between respiratory viruses and the oral microbiota, emphasizing how alterations in the oral microbiome and increased production of proinflammatory factors may serve as early, non-invasive biomarkers for predicting the severity of respiratory viral infections. These findings provide insights into novel diagnostic approaches and therapeutic strategies aimed at mitigating respiratory disease severity through monitoring and modulating the oral microbiome.

Chronic obstructive pulmonary disease, asthma, and mechanical ventilation are risk factors for dyspnea in patients with long COVID: A Japanese nationwide cohort study

BACKGROUND

Patients often experience multiple prolonged symptoms following acute coronavirus disease 2019 (COVID-19) recovery, defined as long coronavirus disease (COVID). Patients with long COVID may experience dyspnea during acute and post-acute phases. Therefore, this study aimed to identify specific risk factors for dyspnea in patients with long COVID.

METHODS

Hospitalized patients with COVID-19, aged ≥18 years, were enrolled in this multicenter cohort study conducted at 26 medical institutions across Japan. Clinical data during hospitalization and patient-reported outcomes after discharge at the 3, 6, and 12-month follow-ups were retrieved from medical records and paper-based or smartphone application-based questionnaires, respectively.

RESULTS

Generalized linear mixed model (GLMM) analysis of prolonged dyspnea at each time point during follow-up showed that this symptom was associated with chronic obstructive pulmonary disease (COPD) (odds ratio [OR], 2.74; 95% confidence interval [CI], 1.31-5.74), asthma (OR, 2.21; 95%CI, 1.17-4.16), and ventilator management (OR, 3.10; 95%CI, 1.65-5.83). In addition, patients with COPD (44.4%) and ventilator management (25.0%) were more frequently associated with delayed dyspnea onset. The generalized estimating equations analysis results with multiple imputed datasets, conducted as a sensitivity analysis, confirmed the adjusted GLMM analysis results.

CONCLUSIONS

Prolonged dyspnea was associated with COPD, asthma, and severe infection that required mechanical ventilation in the Japanese population with long COVID. Further investigation is needed to clarify its mechanism and develop prophylactic and therapeutic strategies for dyspnea in patients with long COVID.

Profibrotic monocyte-derived alveolar macrophages are expanded in patients with persistent respiratory symptoms and radiographic abnormalities after COVID-19

Monocyte-derived alveolar macrophages drive lung injury and fibrosis in murine models and are associated with pulmonary fibrosis in humans. Monocyte-derived alveolar macrophages have been suggested to develop a phenotype that promotes lung repair as injury resolves. We compared single-cell and cytokine profiling of the alveolar space in a cohort of 35 patients with post-acute sequelae of COVID-19 who had persistent respiratory symptoms and abnormalities on a computed tomography scan of the chest that subsequently improved or progressed. The abundance of monocyte-derived alveolar macrophages, their gene expression programs, and the level of the monocyte chemokine CCL2 in bronchoalveolar lavage fluid positively associated with the severity of radiographic fibrosis. Monocyte-derived alveolar macrophages from patients with resolving or progressive fibrosis expressed the same set of profibrotic genes. Our findings argue against a distinct reparative phenotype in monocyte-derived alveolar macrophages, highlighting their utility as a biomarker of failed lung repair and a potential target for therapy.

TGF-β1 overexpression in severe COVID-19 survivors and its implications for early-phase fibrotic abnormalities and long-term functional impairment

Introduction

In post-COVID survivors, transforming growth factor-beta-1 (TGF-β1) might mediate fibroblast activation, resulting in persistent fibrosis.

Methods

In this study, 82 survivors of COVID-19-associated ARDS were examined at 6- and 24-months post-ICU discharge. At 6-months, quantitative CT analysis of lung attenuation was performed and active TGF-β1 was measured in blood and exhaled breath condensate (EBC).

Results

At 6-months of ICU-discharge, patients with reduced DmCO/alveolar volume ratio exhibited higher plasma and EBC levels of active TGF-β1. Plasma TGF-β1 levels were elevated in dyspneic survivors and directly related to the high-attenuation lung volume. In vitro, plasma and EBC from survivors induced profibrotic changes in human primary fibroblasts in a TGF-β receptor-dependent manner. Finally, at 6-months, plasma and EBC active TGF-β1 levels discriminated patients who, 24-months post-ICU-discharge, developed gas exchange impairment.

Discussion

TGF-β1 pathway plays a pivotal role in the early-phase fibrotic abnormalities in COVID-19-induced ARDS survivors, with significant implications for long-term functional impairment.

The correlation between serum levels of laminin, type IV collagen, type III procollagen N-terminal peptide and hyaluronic acid with the progression of post-COVID-19 pulmonary fibrosis

COVID-19 patients often suffer from post-COVID-19 acute sequelae (PASC). Pulmonary fibrosis has the most significant long-term impact on the respiratory health of patients, known as post-COVID-19 pulmonary fibrosis (PC19-PF). PC19-PF can be caused by acute respiratory distress syndrome (ARDS) or COVID-19-induced pneumonia. Individuals who experience COVID-19 pneumonia symptoms (including cough, shortness of breath, dyspnea on exertion, and desaturation) for at least 12 weeks after diagnosis, almost all develop PC19-PF. Extracellular matrix molecules: laminin (LN), type IV collagen (IV Col), procollagen III N-terminal peptide (PIIINP), and hyaluronic acid (HA) are involved in the development and progression of PC19-PF. This study aimed to investigate the relationship between the progression of PC19-PF and serum levels of laminin, IV COL, PIIINP, and hyaluronic acid. This retrospective study included 162 PC19-PF patients treated and 160 healthy controls who received treatment at Shenzhen Longgang District Third People's Hospital, Hebei PetroChina Central Hospital and Changzhi People's Hospital from January 2021 to December 2023. Serum levels of LN, IV COL, PIIINP, and HA were detected by chemiluminescence immunoassay using commercial kits. Predicted forced vital capacity percentage (FVC% pred), predicted carbon monoxide lung diffusion capacity percentage (DLCO% pred), high-resolution computed tomography (HRCT) scores were assessed, and patient mortality was compared with healthy controls. Serum levels of LN, IV Col, PIIINP, and HA were significantly higher in PC19-PF or CTD-ILD patients than in healthy controls (all p < 0.05), and they were further elevated in acute exacerbation cases (all p < 0.01). In patients, HA was positively associated with HRCT scores and negatively associated with FVC% pred and DLCO% pred (all p < 0.05). Serum levels of LN, IV COL, PIIINP, and HA were significantly lower in surviving patients than in those who deceased (all p > 0.05). Serum levels of LN, IV C, PIIINP, and HA may affect the progression of PC19-PF and may serve as indicators of PC19-PF severity.

Effect of apigetrin in pseudo-SARS-CoV-2-induced inflammatory and pulmonary fibrosis in vitro model

SARS-CoV-2 has become a global public health problem. Acute respiratory distress syndrome (ARDS) is the leading cause of death due to the SARS-CoV-2 infection. Pulmonary fibrosis (PF) is a severe and frequently reported COVID-19 sequela. In this study, an in vitro model of ARDS and PF caused by SARS-CoV-2 was established in MH-S, THP-1, and MRC-5 cells using pseudo-SARS-CoV-2 (PSCV). Expression of proinflammatory cytokines (IL-6, IL-1β, and TNF-α) and HIF-1α was increased in PSCV-infected MH-S and THP-1 cells, ARDS model, consistent with other profiling data in SARS-CoV-2-infected patients have been reported. Hypoxia-inducible factor-1 alpha (HIF-1α) siRNA and cobalt chloride were tested using this in vitro model. HIF-1α knockdown reduces inflammation caused by PSCV infection in MH-S and THP-1 cells and lowers elevated levels of CTGF, COLA1, and α-SMA in MRC-5 cells exposed to CPMSCV. Furthermore, apigetrin, a glycoside bioactive dietary flavonoid derived from several plants, including Crataegus pinnatifida, which is reported to be a HIF-1α inhibitor, was tested in this in vitro model. Apigetrin significantly reduced the increased inflammatory cytokine (IL-6, IL-1β, and TNF-α) expression and secretion by PSCV in MH-S and THP-1 cells. Apigetrin inhibited the binding of the SARS-CoV-2 spike protein RBD to the ACE2 protein. An in vitro model of PF induced by SARS-CoV-2 was produced using a conditioned medium of THP-1 and MH-S cells that were PSCV-infected (CMPSCV) into MRC-5 cells. In a PF model, CMPSCV treatment of THP-1 and MH-S cells increased cell growth, migration, and collagen synthesis in MRC-5 cells. In contrast, apigetrin suppressed the increase in cell growth, migration, and collagen synthesis induced by CMPSCV in THP-1 and MH-S MRC-5 cells. Also, compared to control, fibrosis-related proteins (CTGF, COLA1, α-SMA, and HIF-1α) levels were over two-fold higher in CMPSV-treated MRC-5 cells. Apigetrin decreased protein levels in CMPSCV-treated MRC-5 cells. Thus, our data suggest that hypoxia-inducible factor-1 alpha (HIF-1α) might be a novel target for SARS-CoV-2 sequela therapies and apigetrin, representative of HIF-1alpha inhibitor, exerts anti-inflammatory and PF effects in PSCV-treated MH-S, THP-1, and CMPVSC-treated MRC-5 cells. These findings indicate that HIF-1α inhibition and apigetrin would have a potential value in controlling SARS-CoV-2-related diseases.

Lung function and quality of life one year after severe COVID-19 in Brazil

OBJECTIVE

To evaluate symptoms, lung function, and quality of life of a cohort of patients hospitalized for severe COVID-19 12 months after hospital admission.

METHODS

This was a cross-sectional study. We included severe COVID-19 survivors hospitalized in one of three tertiary referral hospitals for COVID-19 in the city of Belo Horizonte, Brazil. Participants were submitted to lung function and six-minute walk tests and completed the EQ-5D-3L questionnaire.

RESULTS

The whole sample comprised 189 COVID-19 survivors (mean age = 59.6 ± 13.4 years) who had been admitted to a ward only (n = 96; 50.8%) or to an ICU (n = 93; 49.2%). At 12 months of follow-up, 43% of patients presented with dyspnea, 27% of whom had a restrictive ventilatory disorder and 18% of whom presented with impaired DLCO. There were no significant differences in FVC, FEV1, and TLC between the survivors with or without dyspnea. However, those who still had dyspnea had significantly more impaired DLCO (14.9% vs. 22.4%; p < 0.020) and poorer quality of life.

CONCLUSIONS

After one year, survivors of severe COVID-19 in a middle-income country still present with high symptom burden, restrictive ventilatory changes, and loss of quality of life. Ongoing follow-up is needed to characterize long COVID-19 and identify strategies to mitigate its consequences.

Multidisciplinary Management Strategies for Long COVID: A Narrative Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of infections to date and has led to a worldwide pandemic. Most patients had a complete recovery from the acute infection, however, a large number of the affected individuals experienced symptoms that persisted more than 3 months after diagnosis. These symptoms most commonly include fatigue, memory difficulties, brain fog, dyspnea, cough, and other less common ones such as headache, chest pain, paresthesias, mood changes, muscle pain, and weakness, skin rashes, and cardiac, endocrine, renal and hepatic manifestations. The treatment of this syndrome remains challenging. A multidisciplinary approach to address combinations of symptoms affecting multiple organ systems has been widely adopted. This narrative review aims to bridge the gap surrounding the broad treatment approaches by providing an overview of multidisciplinary management strategies for the most common long COVID conditions.

Characteristics and determinants of pulmonary long COVID

BACKGROUNDPersistent cough and dyspnea are prominent features of postacute sequelae of SARS-CoV-2 (also termed "long COVID"); however, physiologic measures and clinical features associated with these pulmonary symptoms remain poorly defined. Using longitudinal pulmonary function testing (PFT) and CT imaging, this study aimed to identify the characteristics and determinants of pulmonary long COVID.METHODSThis single-center retrospective study included 1,097 patients with clinically defined long COVID characterized by persistent pulmonary symptoms (dyspnea, cough, and chest discomfort) lasting for 1 or more months after resolution of primary COVID infection.RESULTSAfter exclusion, a total of 929 patients with post-COVID pulmonary symptoms and PFTs were stratified as diffusion impairment and pulmonary restriction, as measured by percentage predicted diffusion capacity for carbon monoxide (DLCO) and total lung capacity (TLC). Longitudinal evaluation revealed diffusion impairment (DLCO ≤ 80%) and pulmonary restriction (TLC ≤ 80%) in 51% of the cohort overall (n = 479). In multivariable modeling regression analysis, invasive mechanical ventilation during primary infection conferred the greatest increased odds of developing pulmonary long COVID with diffusion impairment and restriction (adjusted odds ratio [aOR] = 9.89, 95% CI 3.62-26.9]). Finally, a subanalysis of CT imaging identified radiographic evidence of fibrosis in this patient population.CONCLUSIONLongitudinal PFTs revealed persistent diffusion-impaired restriction as a key feature of pulmonary long COVID. These results emphasize the importance of incorporating PFTs into routine clinical practice for evaluation of long COVID patients with prolonged pulmonary symptoms. Subsequent clinical trials should leverage combined symptomatic and quantitative PFT measurements for more targeted enrollment of pulmonary long COVID patients.FUNDINGNational Institute of Allergy and Infectious Diseases (AI156898, K08AI129705), National Heart, Lung, and Blood Institute (HL153113, OTA21-015E, HL149944), and the COVID-19 Urgent Research Response Fund at the University of Alabama at Birmingham.

Short- and Long-Term Chest-CT Findings after Recovery from COVID-19: A Systematic Review and Meta-Analysis

While ground-glass opacity, consolidation, and fibrosis in the lungs are some of the hallmarks of acute SAR-CoV-2 infection, it remains unclear whether these pulmonary radiological findings would resolve after acute symptoms have subsided. We conducted a systematic review and meta-analysis to evaluate chest computed tomography (CT) abnormalities stratified by COVID-19 disease severity and multiple timepoints post-infection. PubMed/MEDLINE was searched for relevant articles until 23 May 2023. Studies with COVID-19-recovered patients and follow-up chest CT at least 12 months post-infection were included. CT findings were evaluated at short-term (1-6 months) and long-term (12-24 months) follow-ups and by disease severity (severe and non-severe). A generalized linear mixed-effects model with random effects was used to estimate event rates for CT findings. A total of 2517 studies were identified, of which 43 met the inclusion (N = 8858 patients). Fibrotic-like changes had the highest event rate at short-term (0.44 [0.3-0.59]) and long-term (0.38 [0.23-0.56]) follow-ups. A meta-regression showed that over time the event rates decreased for any abnormality (β = -0.137, p = 0.002), ground-glass opacities (β = -0.169, p < 0.001), increased for honeycombing (β = 0.075, p = 0.03), and did not change for fibrotic-like changes, bronchiectasis, reticulation, and interlobular septal thickening (p > 0.05 for all). The severe subgroup had significantly higher rates of any abnormalities (p < 0.001), bronchiectasis (p = 0.02), fibrotic-like changes (p = 0.03), and reticulation (p < 0.001) at long-term follow-ups when compared to the non-severe subgroup. In conclusion, significant CT abnormalities remained up to 2 years post-COVID-19, especially in patients with severe disease. Long-lasting pulmonary abnormalities post-SARS-CoV-2 infection signal a future public health concern, necessitating extended monitoring, rehabilitation, survivor support, vaccination, and ongoing research for targeted therapies.

Association of Monocyte Count With Lung Function and Exercise Capacity Among Hospitalized COVID-19 Survivors: A 2-Year Cohort Study

BACKGROUND

Abnormal changes of monocytes have been observed in acute COVID-19, whereas associations of monocyte count with long COVID were not sufficiently elucidated.

METHODS

A cohort study was conducted among COVID-19 survivors discharged from hospital. The primary outcomes were core symptoms of long COVID, distance walked in 6 min, and lung function, and the secondary outcomes were health-related quality of life and healthcare use after discharge. Latent variable mixture modeling was used to classify individuals into groups with similar trajectory of monocyte count from discharge to 2-year after symptom onset. Multivariable adjusted generalized linear regression models and logistic regression models were used to estimate the associations of monocyte count trajectories and monocyte count at discharge with outcomes.

RESULTS

In total, 1389 study participants were included in this study. Two monocyte count trajectories including high to normal high and normal trajectory were identified. After multivariable adjustment, participants in high to normal high trajectory group had an odds ratio (OR) of 2.52 (95% CI, 1.44-4.42) for smell disorder, 2.27 (1.27-4.04) for 6-min walking distance less than lower limit of normal range, 2.45 (1.08-5.57) for total lung capacity (TLC) < 80% of predicted, 3.37 (1.16-9.76) for personal care problem, and 1.70 (1.12-2.58) for rehospitalization after discharge at 2-year follow-up compared with those in normal trajectory group. Monocyte count at discharge showed similar results, which was associated with smell disorder, TLC < 80% of predicted, diffusion impairment, and rehospitalization.

CONCLUSIONS

Monocyte count may serve as an easily accessible marker for long-term management of people recovering from COVID-19.

Persistent Shortness of Breath in Post-COVID-19 Patients: Inducible Laryngeal Obstruction Can Be a Cause

BACKGROUND

Inducible laryngeal obstruction (ILO) is the adduction of the true vocal folds during inspiration or, less frequently, expiration. Its etiology is unknown.

PURPOSE

This study aimed to identify ILO as a possible cause of shortness of breath (SOB) in post-COVID-19 patients.

METHODS

A retrospective study was conducted on 59 post-COVID-19 adults complaining of SOB. We collected the cases' clinical and chest imaging data, including demographic data, pulmonary function test (PFT), CT chest, and laryngeal endoscopic examination. A visual score was used to assign the severity of the glottic obstruction. The grades of this score ranged from 0 (complete patency) to 3 (almost complete closure).

RESULTS

ILO was detected in 8 out of 59 cases (13.5%). Two cases out of eight had glottic closure grade 1, while five cases had glottic closure grade 2, and one had glottic closure grade 3. There was a positive correlation between ILO grades (the severity of glottic closure) and PFT results (the degree of upper airway restriction). PFTs in ILO have a specific pattern. It was typical for the expiratory loop to be normal and the inspiratory loop to be flattened.

CONCLUSION

ILO is a possible cause of SOB in post-COVID-19 adult cases. It should be considered during evaluation and management.

Characteristics and Determinants of Pulmonary Long COVID

RATIONALE

Persistent cough and dyspnea are prominent features of post-acute sequelae of SARS-CoV-2 (termed 'Long COVID'); however, physiologic measures and clinical features associated with these pulmonary symptoms remain poorly defined.

OBJECTIVES

Using longitudinal pulmonary function testing (PFTs) and CT imaging, this study aimed to identify the characteristics and determinants of pulmonary Long COVID.

METHODS

The University of Alabama at Birmingham Pulmonary Long COVID cohort was utilized to characterize lung defects in patients with persistent pulmonary symptoms after resolution primary COVID infection. Longitudinal PFTs including total lung capacity (TLC) and diffusion limitation of carbon monoxide (DLCO) were used to evaluate restriction and diffusion impairment over time in this cohort. Analysis of chest CT imaging was used to phenotype the pulmonary Long COVID pathology. Risk factors linked to development of pulmonary Long COVID were estimated using univariate and multivariate logistic regression models.

MEASUREMENTS AND MAIN RESULTS

Longitudinal evaluation 929 patients with post-COVID pulmonary symptoms revealed diffusion impairment (DLCO ≤80%) and restriction (TLC ≤80%) in 51% of the cohort (n=479). In multivariable logistic regression analysis (adjusted odds ratio; aOR, 95% confidence interval [CI]), invasive mechanical ventilation during primary infection conferred the greatest increased odds of developing pulmonary Long COVID with diffusion impaired restriction (aOR=10.9 [4.09-28.6]). Finally, a sub-analysis of CT imaging identified evidence of fibrosis in this population.

CONCLUSIONS

Persistent diffusion impaired restriction was identified as a key feature of pulmonary Long COVID. Subsequent clinical trials should leverage combined symptomatic and quantitative PFT measurements for more targeted enrollment of pulmonary Long COVID patients.

Elevated hyaluronic acid levels in severe SARS-CoV-2 infection in the post-COVID-19 era

Objective

Human identical sequences of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) promoted the coronavirus disease 2019 (COVID-19) progression by upregulating hyaluronic acid (HA) via NamiRNA-enhancer network, based on previous experimental research. This study aimed to investigate the predictive value of HA for the severity of SARS-CoV-2 infection in the post-COVID-19 era.

Methods

A total of 217 consecutive patients with COVID-19 were enrolled at Beijing Ditan Hospital between July 2023 and October 2023. HA levels were analyzed using biochemical detector. Logistic regression analysis was used to screen independent factors for severe COVID-19. The predictive performance of HA for severe infection was assessed by ROC curve. Furthermore, the relationship between HA levels and COVID-19 severity was investigated using multivariate logistic regression models after adjustment for potential confounders.

Results

According to the cut-off value of HA, COVID-19 patients were divided into HA < 90 ng/mL group (80 cases) and HA ≥ 90 ng/mL group (137 cases). High HA levels were positively associated with the severe SARS-CoV-2 infection, including elevated inflammatory indicators, severe lung involvement, prolonged clinical course, and higher incidence of respiratory failure and death (P < 0.05). Logistic regression analysis suggested that HA was an independent predictor of severe COVID-19 (OR = 4.540, 95% CI = 2.105-9.790, P < 0.001). ROC curve analysis showed that the AUC of HA for severe infection was 0.724. HA levels were significantly higher in COVID-19 cases compared to the healthy population (123.9 (82.6, 174.1) vs. 50.5 (37.8, 66.8), P < 0.001), but similar to those with non-SARS-CoV-2 lung infection (121.6 (78.5, 175.6) vs. 106.0 (66.5, 149.7), P = 0.244). We also found that the first COVID-19 infections had higher HA levels (118.8 (79.5, 174.3) vs. 85.0 (61.1, 128.8), P < 0.001) and a higher proportion of severe infection (37.1% vs. 21.3%, P = 0.043) than re-infections. However, HA expression failed to fully return to normal levels with infection recovery (204.7 (152.9, 242.2) vs. 97.0 (69.3, 137.3), P < 0.001).

Conclusion

HA was associated with severe SARS-CoV-2 infection and could be used as a novel serum biomarker to predict the risk of COVID-19 progression in the post-COVID-19 era.

TRPA1: A promising target for pulmonary fibrosis?

Pulmonary fibrosis is a disease characterized by progressive scar formation and the ultimate manifestation of numerous lung diseases. It is known as "cancer that is not cancer" and has attracted widespread attention. However, its formation process is very complex, and the mechanism of occurrence has not been fully elucidated. Current research has found that TRPA1 may be a promising target in the pathogenesis of pulmonary fibrosis. The TRPA1 channel was first successfully isolated in human lung fibroblasts, and it was found to have a relatively concentrated distribution in the lungs and respiratory tract. It is also involved in various acute and chronic inflammatory processes of lung diseases and may even play a core role in the progression and/or prevention of pulmonary fibrosis. Natural ligands targeting TRPA1 could offer a promising alternative treatment for pulmonary diseases. Therefore, this review delves into the current understanding of pulmonary fibrogenesis, analyzes TRPA1 biological properties and regulation of lung disease with a focus on pulmonary fibrosis, summarizes the TRPA1 molecular structure and its biological function, and summarizes TRPA1 natural ligand sources, anti-pulmonary fibrosis activity and potential mechanisms. The aim is to decipher the exact role of TRPA1 channels in the pathophysiology of pulmonary fibrosis and to consider their potential in the development of new therapeutic strategies.

The spike protein of SARS-CoV-2 induces inflammation and EMT of lung epithelial cells and fibroblasts through the upregulation of GADD45A

Lung epithelial cells and fibroblasts poorly express angiotensin-converting enzyme 2, and the study aimed to investigate the role of the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on inflammation and epithelial-mesenchymal transition (EMT) in two lung cell lines and to understand the potential mechanism. Lung epithelial cells (BEAS-2B) and fibroblasts (MRC-5) were treated with the spike protein, then inflammatory and EMT phenotypes were detected by enzyme-linked immunosorbent assay, Transwell, and western blot assays. RNA-sequence and bioinformatic analyses were performed to identify dysregulated genes. The roles of the candidate genes were further investigated. The results showed that treatment with 1,000 ng/mL of spike protein in two lung cell lines caused increased levels of IL-6, TNF-α, CXCL1, and CXCL3, and the occurrence of EMT. RNA-sequence identified 4,238 dysregulated genes in the spike group, and 18 candidate genes were involved in both inflammation- and EMT-related processes. GADD45A had the highest verified fold change (abs), and overexpression of GADD45A promoted the secretion of cytokines and EMT in the two lung cell lines. In conclusion, the spike protein induces inflammation and EMT in lung epithelial cells and fibroblasts by upregulating GADD45A, providing a new target to inhibit inflammation and EMT.

Comparing postacute care healthcare charges after hospitalisation due to influenza or COVID-19 infection in an all-payer administrative dataset in the USA: a retrospective cohort study

Objective

SARS-CoV-2 infection often causes a persistent syndrome of multiorgan dysfunction with symptoms that may be debilitating. Individuals seeking care for this syndrome are likely to generate significant healthcare utilisation and spending. It is unknown if healthcare costs after SARS-CoV-2 infection differ from those after influenza infection.

Methods and analysis

We used an all-payer administrative dataset comprised coding and billing data from 446 hospitals in the USA that use a financial analytics platform by Strata Decision Technology. The deidentified analytical sample included patients aged 18 years or older who were admitted to a hospital between July 2018 and May 2021 with an International Classification of Disease-10 code for COVID-19 or influenza. Analyses were stratified by age (18-44, 45-64 and 65+) and need for ventilation during acute hospitalisation. Linear regression models were used to evaluate the relationship between infection type (COVID-19 or influenza) and cumulative charges between 1 and 5 months after hospitalisation. Independent variables included medical comorbidities, health system classification and prehospitalisation charges, among others.

Results

Of 110 381 patients included in our analysis, 94 927 (86.0%) were hospitalised for COVID-19 and 15 454 (14.0%) were hospitalised for influenza. Patients hospitalised for COVID-19 generated a median of US$5248 (inter-quartile range (IQR) US$25693) in postacute healthcare charges, whereas patients hospitalised for influenza generated a median of US$8463 (IQR US$41063). Compared with influenza, linear model results demonstrated no significant differences in postacute charges among patients hospitalised with COVID-19.

Conclusion

Our findings suggest that individual healthcare expenditures after acute COVID-19 infection are not significantly different from those after influenza infection.

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.

Krüppel-like factor 15 counteracts endoplasmic reticulum stress and suppresses lung fibroblast proliferation and extracellular matrix accumulation

The incidence of pulmonary fibrosis is on the rise, and existing treatments have limited efficacy in improving patient survival. The purpose of this study was to reveal the potential of Krüppel-like factor (KLF)15 activation in alleviating pulmonary fibrosis. Transforming growth factor beta (TGF-β) was utilized to induce lung fibroblasts to establish an in vitro model of pulmonary fibrosis. The impacts of TGF-β and KLF15 level on cell proliferation, migration, extracellular matrix (ECM) accumulation, and endoplasmic reticulum stress (ERS) were assessed. Additionally, tunicamycin, an ERS agonist, was used to investigate the role of ERS in KLF15 regulation. The results showed that KLF15 was dropped in response to TGF-β treatment. However, KLF15 overexpression reduced cell proliferation, migration, ECM accumulation, and ERS, alleviating the effects of TGF-β stimulation. Subsequent treatment with tunicamycin diminished the effects of KLF15 overexpression, demonstrating that ERS mediated the modulation of KLF15. KLF15 acts against ERS and suppresses excessive proliferation and ECM accumulation in lung fibroblast. These findings suggest that activating KLF15 is a promising strategy for alleviating pulmonary fibrosis.

Risk factors for the development of interstitial lung disease following severe COVID-19 pneumonia and outcomes of systemic corticosteroid therapy: 3-month follow-up

BACKGROUND

We aimed to evaluate the pulmonary involvement status, its related factors, and pulmonary function test (PFT) results in the first month follow-up in patients who were discharged for severe Covid-19 pneumonia, and to assess the efficacy of corticosteroid treatment on these parameters in severe pulmonary involvement patients.

METHODS

We retrospectively analyzed all consecutive patients who applied to our COVID-19 follow-up clinic at the end of the first month of hospital discharge. Functional and radiological differences were compared after 3 months of corticosteroid treatment in severe pulmonary involvement group. Results We analyzed 391 patients with "pulmonary parenchymal involvement" (PPIG) and 162 patients with "normal lung radiology" (NLRG). 122 patients in the PPIG (corticosteroid-required interstitial lung disease group (CRILD)) had severe pulmonary involvement with frequent symptoms and required corticosteroid prescription. Pulmonary involvement was more common in males and elder patients (P<0.001, for both). Being smoker and elderly were associated with a higher risk-ratio in predicting to be in PPIG (OR:2.250 and OR:1.057, respectively). Smokers, male and elderly patients, and HFNO2 support during hospitalization were risk factors for being a patient with CRILD (OR:2.737, OR:4.937, OR:4.756, and OR:2.872, respectively). After a three-months of methylprednisolone medication, a good response was achieved on radiological findings and PFT results in CRILD.

CONCLUSIONS

In conclusion, after severe COVID-19 pneumonia, persistent clinical symptoms and pulmonary parenchymal involvement would be inevitable in elder and smoker patients. Moreover, corticosteroid treatment in patients with severe parenchymal involvement was found to be effective in the improvement of radiological and functional parameters.

Post-COVID-19 Pulmonary Fibrosis: Facts-Challenges and Futures: A Narrative Review

Patients with coronavirus disease 2019 (COVID-19) usually suffer from post-acute sequelae of coronavirus disease 2019 (PASC). Pulmonary fibrosis (PF) has the most significant long-term impact on patients' respiratory health, called post-COVID-19 pulmonary fibrosis (PC19-PF). PC19- PF can be caused by acute respiratory distress syndrome (ARDS) or pneumonia due to COVID-19. The risk factors of PC19-PF, such as older age, chronic comorbidities, the use of mechanical ventilation during the acute phase, and female sex, should be considered. Individuals with COVID-19 pneumonia symptoms lasting at least 12 weeks following diagnosis, including cough, dyspnea, exertional dyspnea, and poor saturation, accounted for nearly all disease occurrences. PC19-PF is characterized by persistent fibrotic tomographic sequelae associated with functional impairment throughout follow-up. Thus, clinical examination, radiology, pulmonary function tests, and pathological findings should be done to diagnose PC19-PF patients. PFT indicated persistent limitations in diffusion capacity and restrictive physiology, despite the absence of previous testing and inconsistency in the timeliness of assessments following acute illness. It has been hypothesized that PC19-PF patients may benefit from idiopathic pulmonary fibrosis treatment to prevent continued infection-related disorders, enhance the healing phase, and manage fibroproliferative processes. Immunomodulatory agents might reduce inflammation and the length of mechanical ventilation during the acute phase of COVID-19 infection, and the risk of the PC19-PF stage. Pulmonary rehabilitation, incorporating exercise training, physical education, and behavioral modifications, can improve the physical and psychological conditions of patients with PC19-PF.

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.

Multicentre study on the accuracy of lung ultrasound in the diagnosis and monitoring of respiratory sequelae in the medium and long term in patients with COVID-19

Introduction

Lung ultrasound (LUS) has proven to be a more sensitive tool than radiography (X-ray) to detect alveolar-interstitial involvement in COVID-19 pneumonia. However, its usefulness in the detection of possible pulmonary alterations after overcoming the acute phase of COVID-19 is unknown. In this study we proposed studying the utility of LUS in the medium- and long-term follow-up of a cohort of patients hospitalized with COVID-19 pneumonia.

Materials and methods

This was a prospective, multicentre study that included patients, aged over 18 years, at 3 ± 1 and 12 ± 1 months after discharge after treatment for COVID-19 pneumonia. Demographic variables, the disease severity, and analytical, radiographic, and functional clinical details were collected. LUS was performed at each visit and 14 areas were evaluated and classified with a scoring system whose global sum was referred to as the "lung score." Two-dimensional shear wave elastography (2D-SWE) was performed in 2 anterior areas and in 2 posterior areas in a subgroup of patients. The results were compared with high-resolution computed tomography (CT) images reported by an expert radiologist.

Results

A total of 233 patients were included, of whom 76 (32.6%) required Intensive Care Unit (ICU) admission; 58 (24.9%) of them were intubated and non-invasive respiratory support was also necessary in 58 cases (24.9%). Compared with the results from CT images, when performed in the medium term, LUS showed a sensitivity (S) of 89.7%, specificity (E) 50%, and an area under the curve (AUC) of 78.8%, while the diagnostic usefulness of X-ray showed an S of 78% and E of 47%. Most of the patients improved in the long-term evaluation, with LUS showing an efficacy with an S of 76% and E of 74%, while the X-ray presented an S of 71% and E of 50%. 2D-SWE data were available in 108 (61.7%) patients, in whom we found a non-significant tendency toward the presentation of a higher shear wave velocity among those who developed interstitial alterations, with a median kPa of 22.76 ± 15.49) versus 19.45 ± 11.39; p = 0.1).

Conclusion

Lung ultrasound could be implemented as a first-line procedure in the evaluation of interstitial lung sequelae after COVID-19 pneumonia.

Lung recovery with prolonged ECMO following fibrotic COVID-19 acute respiratory distress syndrome

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has been associated with acute respiratory distress syndrome (ARDS) and in some cases with pulmonary fibrosis. There is limited information regarding the long-term outcomes of patients who develop severe COVID-19 infection and subsequent pulmonary fibrosis. We present a patient with severe ARDS due to COVID-19 who required prolonged extra-corporeal oxygenation support and eventually recovered significant lung function. This case is unique because the patient survived one of the longest reported runs on extra-corporeal membrane oxygenation without requiring lung transplantation. Further, our patient developed severe parenchymal and airway distortion but ultimately resolved pulmonary fibrosis many months into the hospitalization. In addition to our detailed case discussion, we will provide a focused review on pulmonary fibrosis post COVID-19.

Predictors of pulmonary sequelae after COVID-19 pneumonia: A 12-month follow-up study

Background

Since the beginning of the SARS-CoV-2 pandemic, over 550 million people have been infected worldwide. Despite these large numbers, the long-term pulmonary consequences of COVID-19 remain unclear.

Aims

The aim of this single-center observational cohort study was to identify and characterize pulmonary sequelae of COVID-19 at 12 months from hospitalization and to reveal possible predictors for the persistence of long-term lung consequences.

Methods

Based on the persistence or absence of radiological changes after 12 months from hospitalization, the whole population was categorized into NOT-RECOVERED (NOT-REC) and RECOVERED (REC) groups, respectively. Clinical and pulmonary function data tests and clinical data were also collected and compared in the two groups. In the NOT-REC group, high resolution computed tomography (HRCT) images were semiquantitatively scored analyzing ground-glass opacities (GGO), interstitial thickening (IT), consolidations (CO), linear and curvilinear band opacities, and bronchiectasis for each lung lobe. Logistic regression analyses served to detect the factors associated with 12-month radiological consequences.

Results

Out of the 421 patients followed after hospitalization for SARS-CoV-2 pneumonia, 347 met inclusion and exclusion criteria and were enrolled in the study. The NOT-REC patients (n = 24; 6.9%) were significantly older [67 (62-76) years vs. 63 (53-71) years; p = 0.02], more frequently current smokers [4 (17%) vs. 12 (4%); p = 0.02], and with more severe respiratory failure at the time of hospitalization [PaO₂/FiO₂ at admission: 201 (101-314) vs. 295 (223-343); p = 0.01] compared to REC group (n = 323; 93.1%). On multivariable analysis, being a current smoker resulted in an independent predictor for lung sequelae after 12 months from hospitalization [5.6 OR; 95% CI (1.41-22.12); p = 0.01].

Conclusion

After 12 months from hospital admission, a limited number of patients displayed persistent pulmonary sequelae with minimal extension. Being a current smoker at the time of SARS-CoV-2 infection is an independent predictive factor to lung consequences, regardless of the disease severity.

Role of Ferroptosis in Regulating the Epithelial-Mesenchymal Transition in Pulmonary Fibrosis

Idiopathic pulmonary fibrosis is a chronic interstitial lung disease whose pathogenesis involves a complex interaction of cell types and signaling pathways. Lung epithelial cells responding to repeated injury experience persistent inflammation and sustained epithelial-mesenchymal transition (EMT). The persistence of EMT-induced signals generates extracellular matrix accumulation, thereby causing fibrosis. Ferroptosis is a newly characterized iron-dependent non-apoptotic regulated cell death. Increased iron accumulation can increase iron-induced oxidant damage in alveolar epithelial cells. Studies have demonstrated that iron steady states and oxidation steady states play an important role in the iron death regulation of EMT. This review summarizes the role of ferroptosis in regulating EMT in pulmonary fibrosis, aiming to provide a new idea for the prevention and treatment of this disease.

COVID-19 Heart Lesions in Children: Clinical, Diagnostic and Immunological Changes

In the beginning of COVID-19, the proportion of confirmed cases in the pediatric population was relatively small and there was an opinion that children often had a mild or asymptomatic course of infection. Our understanding of the immune response, diagnosis and treatment of COVID-19 is highly oriented towards the adult population. At the same time, despite the fact that COVID-19 in children usually occurs in a mild form, there is an incomplete understanding of the course as an acute infection and its subsequent manifestations such as Long-COVID-19 or Post-COVID-19, PASC in the pediatric population, correlations with comorbidities and immunological changes. In mild COVID-19 in childhood, some authors explain the absence of population decreasing T and B lymphocytes. Regardless of the patient's condition, they can have the second phase, related to the exacerbation of inflammation in the heart tissue even if the viral infection was completely eliminated-post infectious myocarditis. Mechanism of myocardial dysfunction development in MIS-C are not fully understood. It is known that various immunocompetent cells, including both resident inflammatory cells of peripheral tissues (for example macrophages, dendritic cells, resident memory T-lymphocytes and so on) and also circulating in the peripheral blood immune cells play an important role in the immunopathogenesis of myocarditis. It is expected that hyperproduction of interferons and the enhanced cytokine response of T cells 1 and 2 types contribute to dysfunction of the myocardium. However, the role of Th1 in the pathogenesis of myocarditis remains highly controversial. At the same time, the clinical manifestations and mechanisms of damage, including the heart, both against the background and after COVID-19, in children differ from adults. Further studies are needed to evaluate whether transient or persistent cardiac complications are associated with long-term adverse cardiac events.

Exploration of the common genetic landscape of COVID-19 and male infertility

Background

COVID-19 has spread widely across continents since 2019, causing serious damage to human health. Accumulative research uncovered that SARS-CoV-2 poses a great threat to male fertility, and male infertility (MI) is a common comorbidity for the COVID-19 pandemic. The aim of the study was to explore the cross-talk molecular mechanisms between COVID-19 and MI.

Materials and methods

A total of four transcriptome data regarding COVID-19 and MI were downloaded from the Gene Expression Omnibus (GEO) repository, and were divided for two purposes (initial analysis and external validation). Differentially expressed genes (DEGs) analysis, GO and pathway annotation, protein-protein interaction (PPI) network, connectivity ranking, ROC analysis, immune infiltration, and translational and post-translational interaction were performed to gain hub COVID-19-related DEGs (CORGs). Moreover, we recorded medical information of COVID-19 patients with MI and matched healthy controls, and harvested their sperm samples in the university hospital. Expressions of hub CORGs were detected through the qRT-PCR technique.

Results

We identified 460 overlapped CORGs in both the COVID-19 DEGs and MI DEGs. CORGs were significantly enriched in DNA damage and repair-associated, cell cycle-associated, ubiquitination-associated, and coronavirus-associated signaling. Module assessment of PPI network revealed that enriched GO functions were closely related to cell cycle and DNA metabolism processes. Pharmacologic agent prediction displayed protein-drug interactions of ascorbic acid, biotin, caffeine, and L-cysteine with CORGs. After connectivity ranking and external validation, three hub CORGs (ENTPD6, CIB1, and EIF3B) showed good diagnostic performance (area under the curve > 0.75). Subsequently, three types of immune cells (CD8+ T cells, monocytes, and macrophages M0) were dominantly enriched, and 24 transcription factor-CORGs interactions and 13 miRNA-CORGs interactions were constructed in the network. Finally, qRT-PCR analysis confirmed that there were significant differences in the expression of hub CORGs (CIB1 and EIF3B) between the patient and control groups.

Conclusion

The present study identified and validated hub CORGs in COVID-19 and MI, and systematically explored molecular interactions and regulatory features in various biological processes. Our data provide new insights into the novel biomarkers and potential therapeutic targets of COVID-19-associated MI.

Evolution and long‑term respiratory sequelae after severe COVID-19 pneumonia: nitric oxide diffusion measurement value

INTRODUCTION

There are no published studies assessing the evolution of combined determination of the lung diffusing capacity for both nitric oxide and carbon monoxide (DL_NO and DL_CO) 12 months after the discharge of patients with COVID-19 pneumonia.

METHODS

Prospective cohort study which included patients who were assessed both 3 and 12 months after an episode of SARS-CoV-2 pneumonia. Their clinical status, health condition, lung function testings (LFTs) results (spirometry, DL_NO-DL_CO analysis, and six-minute walk test), and chest X-ray/computed tomography scan images were compared.

RESULTS

194 patients, age 62 years (P_25-75, 51.5-71), 59% men, completed the study. 17% required admission to the intensive care unit. An improvement in the patients' exercise tolerance, the extent of the areas of ground-glass opacity, and the LFTs between 3 and 12 months following their hospital discharge were found, but without a decrease in their degree of dyspnea or their self-perceived health condition. DL_NO was the most significantly altered parameter at 12 months (19.3%). The improvement in DL_NO-DL_CO mainly occurred at the expense of the recovery of alveolar units and their vascular component, with the membrane factor only improving in patients with more severe infections.

CONCLUSIONS

The combined measurement of DL_NO-DL_CO is the most sensitive LFT for the detection of the long-term sequelae of COVID-19 pneumonia and it explain better their pathophysiology.

Pulmonary fibrosis in patients with COVID-19: A review

The viral infectious disease pandemic caused by SARS-CoV-2 has affected over 500 million people and killed over 6 million. This is the official data provided by the WHO as of the end of May 2022. Among people who have recovered from COVID-19, post-COVID syndrome is quite common. Scattered epidemiological studies on post-COVID syndrome, however, indicate its high relevance. One of the manifestations of post-COVID syndrome is the development of pulmonary fibrosis (PF). This article is devoted to the analysis of literature data on epidemiology, immunomorphology, as well as X-ray morphological and functional characteristics of PF in patients with post-COVID syndrome. Attention is drawn to the various phenotypes of the post-COVID syndrome and the incidence of PF, which, as clinical practice shows, is most common in people who have had severe COVID-19. This article discusses in detail the molecular biological and immunological mechanisms of PF development. The fibrotic process of the lung parenchyma is not an early manifestation of the disease; as a rule, radiomorphological signs of this pathological process develop after four weeks from the onset of acute manifestations of a viral infection. The characteristic signs of PF include those that indicate the process of remodulation of the lung tissue: volumetric decrease in the lungs, cellular degeneration of the lung parenchyma, bronchiectasis and traction bronchiolectasis. The process of remodulating the lung tissue, in the process of fibrosis, is accompanied by a violation of the lung function; a particularly sensitive test of functional disorders is a decrease in the diffusion capacity of the lung tissue. Therefore, in the process of monitoring patients with post-COVID syndrome, a dynamic study of the ventilation function of the lungs is recommended. The main clinical manifestation of PF is dyspnea that occurs with minimal exertion. Shortness of breath also reflects another important aspect of fibrous remodulation of the lung parenchyma oxygen dissociation is disturbed, which reflects a violation of the gas exchange function of the lungs. There are no generally accepted treatments for PF in post-COVID syndrome. The literature considers such approaches as the possibility of prescribing antifibrotic therapy, hyaluronidase, and medical gases: thermal helium, nitric oxide, and atomic hydrogen. The article draws attention to the unresolved issues of post-covid PF in people who have had COVID-19.

Anti-racist strategies for clinical and translational research: Design, implementation, and lessons learned from a new course

Translational research should examine racism and bias and improve health equity. We designed and implemented a course for the Master of Science in Clinical Investigation program of the Northwestern University Clinical and Translational Sciences Institute. We describe curriculum development, content, outcomes, and revisions involving 36 students in 2 years of "Anti-Racist Strategies for Clinical and Translational Science." Ninety-six percent of students reported they would recommend the course. Many reported changes in research approaches based on course content. A course designed to teach anti-racist research design is feasible and has a positive short-term impact on learners.

Molecular Pathogenesis of Fibrosis, Thrombosis and Surfactant Dysfunction in the Lungs of Severe COVID-19 Patients

The global scope and scale of the SARS-CoV-2 pandemic led to huge amounts of important data from clinical observations and experimental analyses being collected, in particular, regarding the long-term impact of COVID-19 on lung tissue. Visible changes in lung tissue mainly relate to the destruction of the alveolar architecture, dense cellularity, and pulmonary fibrosis with myofibroblast proliferation and collagen deposition. These changes are the result of infection, mainly with virus variants from the first pandemic waves (Alpha to Delta). In addition, proper regulation of immune responses to pathogenic viral stimuli is critical for the control of and recovery from tissue/organ damage, including in the lungs. We can distinguish three main processes in the lungs during SARS-CoV-2 infection: damage or deficiency of the pulmonary surfactant, coagulation processes, and fibrosis. Understanding the molecular basis of these processes is extremely important in the context of elucidating all pathologies occurring after virus entry. In the present review, data on the abovementioned three biochemical processes that lead to pathological changes are gathered together and discussed. Systematization of the knowledge is necessary to explore the three key pathways in lung tissue after SARS-CoV-2 virus infection as a result of a prolonged and intense inflammatory process in the context of pulmonary fibrosis, hemostatic disorders, and disturbances in the structure and/or metabolism of the surfactant. Despite the fact that the new Omicron variant does not affect the lungs as much as the previous variants, we cannot ignore the fact that other new mutations and emerging variants will not cause serious damage to the lung tissue. In the future, this review will be helpful to stratify the risk of serious complications in patients, to improve COVID-19 treatment outcomes, and to select those who may develop complications before clinical manifestation.

Impact of prior vaccination on clinical outcomes of patients with COVID-19

Fully vaccinated people remain at risk of Coronavirus Disease 2019 (COVID-19). We examined association between prior vaccination and clinical outcomes in patients with COVID-19. Overall, 387 patients with mild-to-severe COVID-19 were enrolled. Patients were considered fully vaccinated at least 14, 7, and 14 days after receiving the second dose of ChAdOx1 nCoV-19 or mRNA-1273, second dose of BNT162b2, or single dose of Ad26.COV2.S, respectively. The primary outcomes (risk of pneumonia, requirement of supplemental oxygen, and progression to respiratory failure) were compared between vaccinated and unvaccinated patients. Logistic regression analysis was performed to identify factors associated with the outcomes. There were 204 and 183 patients in the vaccinated and unvaccinated groups, respectively. The vaccinated group was significantly older and had more comorbidities than the unvaccinated group. Patients in the unvaccinated group were significantly more likely to develop pneumonia (65.6% vs. 36.8%) or require supplemental oxygen (29.0 vs. 15.7%) than the vaccinated group. The vaccinated group had a significantly shorter time from symptom onset to hospital discharge than the unvaccinated group (10 vs. 11 days; p<0.001). The proportion of patients who progressed to respiratory failure did not differ significantly between groups. In multivariable analyses, vaccination was associated with an approximately 70% and 82% lower likelihood of pneumonia and supplemental oxygen requirement, respectively. Being vaccinated was associated with a significantly lower risk of pneumonia and severe disease when breakthrough infection developed. Our findings support continuous efforts to increase vaccine coverage in populations.

Association between active cytomegalovirus infection and lung fibroproliferation in adult patients with acute respiratory distress syndrome: a retrospective study

Background

Cytomegalovirus (CMV) has high seroprevalence, and its active infection is associated with several adverse prognoses in adult patients with acute respiratory distress syndrome (ARDS). However, the role of active CMV infection in ARDS-associated fibroproliferation is unknown. This study aimed at determining the association between active CMV infection and lung fibroproliferation in adult patients with ARDS.

Methods

We retrospectively reviewed the medical records of all adult patients with ARDS who were admitted to the intensive care unit (ICU) from January 2018 to December 2020 at a national university-affiliated hospital in China. Study subjects were divided into active and non-active CMV infection groups based on CMV DNAemia within a 28-day ICU hospitalization. Lung fibroproliferation was measured using chest high-resolution computed tomography (HRCT) and N-terminal peptide of serum procollagen III (NT-PCP-III) within the first 28 days of ICU admission. Pulmonary fibrosis, clinical features, laboratory findings, treatment measures, and clinical outcomes were compared between the two groups.

Results

Among the 87 ARDS patients included in this study, the incidence of active CMV infection was 16.1% within the 28-day ICU admission period. In logistic regression analyze, active CMV infection was found to be associated with higher pulmonary fibrogenesis, pulmonary fibrosis score, and NT-PCP-III level (P < 0.05). The duration of ICU stay in ARDS patients with active CMV infection was significantly higher than in those without active CMV infection (P < 0.05).

Conclusions

Among adult patients with ARDS, active CMV infection was related to poor clinical outcomes. Active CMV infection was associated with ARDS-associated fibroproliferation. Prophylactic and preemptive use of anti-CMV agents on pulmonary fibrosis should be assessed to determine a consensus therapeutic strategy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07747-y.

Distal Lung Inflammation Assessed by Alveolar Concentration of Nitric Oxide Is an Individualised Biomarker of Severe COVID-19 Pneumonia

Pulmonary sequelae as assessed by pulmonary function tests (PFTs) are often reported in patients infected by SARS-CoV-2 during the post-COVID-19 period. Little is known, however, about the status of pulmonary inflammation during clinical recovery after patients’ discharge from the hospitals. We prospectively measured PFTs coupled with the exhaled nitric oxide (NO) stemming from the proximal airways (FeNO) and the distal lung (CaNO) in 169 consecutive patients with varying degrees of the severity of COVID-19 six weeks to one year after acute infection by SARS-CoV-2. The proportions of patients with abnormal PFTs, defined as the presence of either obstructive/restrictive patterns or impaired lung gas transfer, or both, increased with the severity of the initial lung disease (15, 30, and 52% in patients with mild, moderate, and severe COVID-19). FeNO values remained within normal ranges and did not differ between the three groups of patients. CaNO, however, was significantly higher in patients with severe or critical COVID-19, compared with patients with milder forms of the disease. There was also an inverse relationship between CaNO and DLCO. We conclude that the residual inflammation of the distal lung is still present in the post-COVID-19 follow-up period, in particular, in those patients with an initially severe form of COVID-19. This long-lasting alveolar inflammation might contribute to the long-term development of pulmonary fibrosis and warrants the regular monitoring of exhaled NO together with PFTs in patients with COVID-19.

Factors Affecting the Risk of Interstitial Lung Disease Development in Hospitalized Patients With COVID-19 Pneumonia

BACKGROUND

Coronavirus disease 2019 (COVID-19) related chronic lung changes secondary to severe disease have become well known. The aim of this study was to determine the risk factors that affect the development of interstitial lung disease in subjects with COVID-19 pneumonia who were hospitalized.

METHODS

Patients hospitalized with COVID-19 pneumonia between June 2020 and March 2021 were retrospectively analyzed. Smoking histories, comorbidities, reverse transcriptase polymerase chain reaction test results, laboratory parameters at the time of the diagnosis, oxygen support, the use of corticosteroids with dosage and duration data, the need for ICU care were recorded. High-resolution computed tomographies (HRCT) were obtained for study population in their 3-6 months follow-up visit. The subjects were classified as having residual parenchymal lung disease if a follow-up HRCT revealed parenchymal abnormalities except pure ground-glass opacities (the residual disease group). The control group consisted of the subjects with normal chest radiograph or HRCT in their follow-up visit or the presence of pure ground-glass opacities. Two groups were compared for their demographic and clinical abnormalities, laboratory parameters, treatment regimens, and the need for ICU care.

RESULTS

The study included 446 subjects. The mean ± SD age was 58.4 ± 13.87 years, with 257 men (57.6%). Although 55 subjects had normal HRCT features on their follow-up HRCT, 157 had abnormal lung parenchymal findings. Univariate logistic regression analysis revealed statistically significant results for age, sex, corticosteroid treatment, and the need for ICU care for predicting interstitial lung disease development (P < .001, P = .003, P < .001, and P < .001, respectively). Also, the residual disease group had significantly higher leukocyte and neutrophil counts and lower lymphocyte counts (P < .001, P < .001, P = .004, respectively). Correlated with these findings, neutrophil-to-lymphocyte ratios and platelet-to-lymphocyte ratios were significantly higher in the residual disease group (P < .001 and P = .008, respectively).

CONCLUSIONS

Residual parenchymal disease was observed 3-6 months after discharge in one third of the subjects hospitalized with COVID-19 pneumonia. It was observed that interstitial lung disease developed more frequently in older men and in those subjects with more-severe disease parameters.