Idiopathic Pulmonary Fibrosis: Epidemiology, Diagnosis andOutcomes

Predicting biomarkers related to idiopathic pulmonary fibrosis: Robust ranking aggregation analysis and animal experiment verification

Idiopathic pulmonary fibrosis (IPF) is a progressive and incurable lung disease characterized by unknown etiology. This study employs robust ranking aggregation to identify consistent differential genes across multiple datasets, aiming to enhance prognostic evaluation and facilitate the development of more effective immunotherapy strategies for IPF. Using the GSE10667, GSE110147, and GSE24206 datasets, the analysis identifies 92 robust differentially expressed genes (DEGs), including SPP1, IGF1, ASPN, and KLHL13, highlighted as potential biomarkers through machine learning and experimental validation. Additionally, significant differences in immune cell types between IPF samples and controls, such as Plasma cells, Macrophages M0, Mast cells resting, T cells CD8, and NK cells resting, inform the construction of diagnostic and survival prediction models, demonstrating good applicability. These findings provide insights into IPF pathophysiology and suggest potential therapeutic targets.

Identification of risk factors for acute exacerbation of idiopathic pulmonary fibrosis based on baseline high-resolution computed tomography: a prospective observational study

BACKGROUND

This study aimed to investigate risk factors for acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) based on baseline high-resolution computed tomography (HRCT).

METHODS

This prospective observational study enrolled patients with IPF treated at the General Hospital of Ningxia Medical University between January 2019 and January 2021. HRCT-derived quantitative parameters at baseline were analyzed.

RESULTS

A total of 102 patients [92 (90.2%) males with a mean age of 67 years] with IPF were included, with a median follow-up of 32 (24-40.5) months. AE occurred in 30 (29.4%) IPF patients. Multivariable logistic regression analysis identified Doppler transthoracic echocardiography suggestive of pulmonary hypertension (PH) (13.43; 95% CI: 4.18-41.09; P < 0.001), honeycombing (OR 1.08; 95% CI: 1.02-1.14; P = 0.013), and whole lung volume (OR 0.99; 95% CI: 0.99-1.00; P = 0.037) as independent risk factors for AE-IPF. The combination of PH, honeycombing, whole lung volume, and the percentage of predicted forced vital capacity (FVC% pred) showed a high area under the curve from receiver operating characteristic curves of 0.888, with a sensitivity of 90% and specificity of 78%.

CONCLUSIONS

This study emphasizes that quantitative CT parameters (honeycombing, whole lung volume) may serve as risk factors for AE-IPF. The combination of honeycombing, whole lung volume, FVC% pred, and PH may aid in predicting AE-IPF.

Single-cell combined with transcriptome sequencing to explore the molecular mechanism of cell communication in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a common, chronic, and progressive lung disease that severely impacts human health and survival. However, the intricate molecular underpinnings of IPF remains elusive. This study aims to delve into the nuanced molecular interplay of cellular interactions in IPF, thereby laying the groundwork for innovative therapeutic approaches in the clinical field of IPF. Sophisticated bioinformatics methods were employed to identify crucial biomarkers essential for the progression of IPF. The GSE122960 single-cell dataset was obtained from the Gene Expression Omnibus (GEO) compendium, and intercellular communication potentialities were scrutinized via CellChat. The random survival forest paradigm was established using the GSE70866 dataset. Quintessential genes were selected through Kaplan-Meier (KM) curves, while immune infiltration examinations, functional enrichment critiques and nomogram paradigms were inaugurated. Analysis of intercellular communication revealed an intimate potential connections between macrophages and various cell types, pinpointing five cardinal genes influencing the trajectory and prognosis of IPF. The nomogram paradigm, sculpted from these seminal genes, exhibits superior predictive prowess. Our research meticulously identified five critical genes, confirming their intimate association with the prognosis, immune infiltration and transcriptional governance of IPF. Interestingly, we discerned these genes' engagement with the EPITHELIAL_MESENCHYMAL_TRANSITION signalling pathway, which may enhance our understanding of the molecular complexity of IPF.

Mendelian randomization study on the causal effect of herpes simplex virus infection on idiopathic pulmonary fibrosis

BACKGROUND

Previous observational studies have shown that past infection of herpes simplex virus (HSV) is associated with idiopathic pulmonary fibrosis (IPF). The present study aims to identify the causal link between HSV infection (exposure factor) and IPF (outcome factor).

RESEARCH DESIGN AND METHODS

To date, the largest publicly available genome-wide association study (GWAS) for HSV infection (1,595 cases and 211,856 controls from Finnish ancestry) and for IPF (1,028 cases and 196,986 controls from Finnish ancestry) were used to perform this two-sample Mendelian randomization (MR) study.

RESULTS

We found no significant pleiotropy or heterogeneity of all selected nine HSV infection-associated genetic instrumental variants (IVs) in IPF GWAS dataset. Interestingly, we found that as HSV infection genetically increased, IPF risk increased based on an inverse-variance weighted (IVW) analysis (odds ratio [OR] = 1.280, 95% confidence interval [CI]: 1.048-1.563; p = 0.015) and weighted median (OR = 1.321, 95% CI: 1.032-1.692; p = 0.027).

CONCLUSIONS

Our analysis suggests a causal effect of genetically increased HSV infection on IPF risk. Thus, HSV infection may be a potential risk factor for IPF.

SGLT-2 inhibitors as novel treatments of multiple organ fibrosis

Fibrosis, a significant health issue linked to chronic inflammatory diseases, affects various organs and can lead to serious damage and loss of function. Despite the availability of some treatments, their limitations necessitate the development of new therapeutic options. Sodium-glucose cotransporter 2 inhibitors (SGLT2i), known for their glucose-lowering ability, have shown promise in offering protective effects against fibrosis in multiple organs through glucose-independent mechanisms. This review explores the anti-fibrotic potential of SGLT2i across different tissues, providing insights into their underlying mechanisms and highlighting recent research advancements. The evidence positions SGLT2i as a potential future treatments for fibrotic diseases.

lncRNA-mRNA Co-Expression and Regulation Analysis in Lung Fibroblasts from Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease marked by abnormal accumulation of extracellular matrix (ECM) due to dysregulated expression of various RNAs in pulmonary fibroblasts. This study utilized RNA-seq data meta-analysis to explore the regulatory network of hub long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) in IPF fibroblasts. The meta-analysis unveiled 584 differentially expressed mRNAs (DEmRNA) and 75 differentially expressed lncRNAs (DElncRNA) in lung fibroblasts from IPF. Among these, BCL6, EFNB1, EPHB2, FOXO1, FOXO3, GNAI1, IRF4, PIK3R1, and RXRA were identified as hub mRNAs, while AC008708.1, AC091806.1, AL442071.1, FAM111A-DT, and LINC01989 were designated as hub lncRNAs. Functional characterization revealed involvement in TGF-β, PI3K, FOXO, and MAPK signaling pathways. Additionally, this study identified regulatory interactions between sequences of hub mRNAs and lncRNAs. In summary, the findings suggest that AC008708.1, AC091806.1, FAM111A-DT, LINC01989, and AL442071.1 lncRNAs can regulate BCL6, EFNB1, EPHB2, FOXO1, FOXO3, GNAI1, IRF4, PIK3R1, and RXRA mRNAs in fibroblasts bearing IPF and contribute to fibrosis by modulating crucial signaling pathways such as FoxO signaling, chemical carcinogenesis, longevity regulatory pathways, non-small cell lung cancer, and AMPK signaling pathways.

Exploring therapeutic targets for molecular therapy of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis is a chronic and progressive interstitial lung disease with a poor prognosis. Idiopathic pulmonary fibrosis is characterized by repeated alveolar epithelial damage leading to abnormal repair. The intercellular microenvironment is disturbed, leading to continuous activation of fibroblasts and myofibroblasts, deposition of extracellular matrix, and ultimately fibrosis. Moreover, pulmonary fibrosis was also found as a COVID-19 complication. Currently, two drugs, pirfenidone and nintedanib, are approved for clinical therapy worldwide. However, they can merely slow the disease's progression rather than rescue it. These two drugs have other limitations, such as lack of efficacy, adverse effects, and poor pharmacokinetics. Consequently, a growing number of molecular therapies have been actively developed. Treatment options for IPF are becoming increasingly available. This article reviews the research platform, including cell and animal models involved in molecular therapy studies of idiopathic pulmonary fibrosis as well as the promising therapeutic targets and their development progress during clinical trials. The former includes patient case/control studies, cell models, and animal models. The latter includes transforming growth factor-beta, vascular endothelial growth factor, platelet-derived growth factor, fibroblast growth factor, lysophosphatidic acid, interleukin-13, Rho-associated coiled-coil forming protein kinase family, and Janus kinases/signal transducers and activators of transcription pathway. We mainly focused on the therapeutic targets that have not only entered clinical trials but were publicly published with their clinical outcomes. Moreover, this work provides an outlook on some promising targets for further validation of their possibilities to cure the disease.

Assessment and Management of Cough in Idiopathic Pulmonary Fibrosis: A Narrative Review

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fatal disease with an unknown cause. It is characterized by symptoms such as cough and breathlessness, which significantly impact patients' quality of life. Cough, in particular, has emerged as a burdensome symptom for individuals with IPF. The etiology of cough in IPF patients is believed to be complex, involving factors related to the disease itself, such as increased sensitivity of cough nerves, lung structural changes, inflammation, and genetic factors, as well as comorbidities and medication effects. Unfortunately, effective treatment options for cough in IPF remain limited, often relying on empirical approaches based on studies involving chronic cough patients in general and the personal experience of physicians. Medications such as opioids and neuromodulators are commonly prescribed but have shown suboptimal efficacy, imposing significant physical, psychological, and economic burdens on patients. However, there is hope on the horizon, as specific purinergic P2 receptor ligand-gated ion channel (P2X3) inhibitors have demonstrated promising antitussive effects in ongoing clinical trials. This review aims to provide a comprehensive overview of the evaluation and management of cough in IPF patients, as well as highlight emerging pharmacological and non-pharmacological approaches that target the cough reflex and are currently being investigated in clinical settings.

Regulation of alveolar macrophage death in pulmonary fibrosis: a review

Pulmonary fibrosis (PF) is a disease in which excessive extracellular matrix (ECM) accumulation occurs in pulmonary mesenchyme, which induces the destruction of alveolar structures and poor prognosis. Macrophage death is responsible for ECM accumulation after alveolar epithelial injury in PF. Depending on the local micro-environments, macrophages can be polarized to either classically activated (M1) or alternatively activated (M2) macrophage phenotypes. In general, M1 macrophages can promote inflammation and sterilization, stop the continuous damage process and prevent excessive repair, while M2 macrophages are anti-inflammatory and promote tissue repair, and excessive M2 macrophage activity may inhibit the absorption and degradation of ECM. Emerging evidence has revealed that death forms such as pyroptosis mediated by inflammasome affect polarization direction and ultimately lead to the development of PF. Pharmacological manipulation of macrophages death signals may serve as a logical therapeutic strategy for PF. This review will focus on the current state of knowledge regarding the regulation and underlying mechanisms of macrophages and their mediators in the influence of macrophage death on the development of PF. We expect to provide help in developing effective therapeutic strategies in clinical settings.

Real-world practice of idiopathic pulmonary fibrosis: Results from a 2000-2016 cohort

The study aimed to investigate comorbidities, major adverse respiratory events, and mortality in patients with idiopathic pulmonary fibrosis (IPF). We established an IPF cohort and a comparative cohort matched for sex, age, and the date of IPF diagnosis. We recorded the most frequent comorbidities, the proportions, and time durations to the episode of major adverse respiratory events and death. Both cohorts were followed up to the end of 2016. We included 921 patients in the IPF cohort and 3,677 individuals in the comparative cohort. Comorbidities associated with IPF included pulmonary hypertension, chronic obstructive pulmonary disease, heart failure, asthma, and gastroesophageal reflux disease. The IPF cohort was more likely to have pneumonia (47.6 vs 12.0%), acute respiratory failure (17.8 vs 4.30%), chronic respiratory failure (4.23 vs 0.63%), and death (36.3 vs 15.0%) than the comparative cohort. The time durations to the first episode of pneumonia, acute respiratory failure, chronic respiratory failure, and death were 2.09 ± 2.98, 3.12 ± 3.62, 3.20 ± 4.03, and 3.27 ± 3.03 years in the IPF cohort. In conclusion, patients with IPF had significant comorbidities, particularly pulmonary and cardiovascular comorbidities. The duration from diagnosis to the major adverse respiratory events or death was short.

Protective effects and mechanism of curcumin in animal models of pulmonary fibrosis: a preclinical systematic review and meta-analysis

Introduction: At present, there is a lack of effective treatment for pulmonary fibrosis (PF), and a number of studies have confirmed that curcumin (CUR) has a good effect on PF. Research Qusetion: Is CUR effective in preclinical trials for PF and what is its mechanism of action? Methods: Animal reports of PF treated with CUR were searched from Pubmed, Embase, Web of Science and Cochrane Library from 1 January 2000 to 19 April 2023 to compare CUR treatment of PF with a no-intervention model group. A previous registration (nsply registration number: INPLASY202360084) of this review protocol was undertaken. Results: The meta-analysis included 27 publications and 29 studies involving 396 animals. CUR significantly improved the degree of fibrosis, levels of inflammation, and oxidative imbalances in lung tissue in animal models of PF. In terms fibrosis, such as HYP content (SMD = -4.96; 95% CI = -6.05 to -3.87; p = 0.000).In terms of inflammatory indicators, such as MPO activity (SMD = -2.12; 95% CI = -4.93 to 0.69; p = 0.000). In terms of oxidation index, such as MDA (SMD = -5.63; 95% CI = -9.66 to -1.6; p = 0.000). Conclusion: CUR significantly improved the degree of fibrosis, levels of inflammation, and oxidative imbalances in lung tissue in animal models of PF. Due to the quantitative and qualitative limitations of current research, more high-quality studies are needed to verify the above conclusion.

The effect of CALIPER-derived parameters for idiopathic pulmonary fibrosis in predicting prognosis, progression, and mortality: a systematic review

BACKGROUND

High-resolution computed tomography (HRCT), as the main tool for monitoring idiopathic pulmonary fibrosis (IPF), is characterized by subjective variability among radiologists and insensitivity to subtle changes. Recently, a few studies have aimed to decrease subjective bias by assessing the severity of IPF using computer software, i.e., Computer-Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER). However, these studies had diverse research directions. In this review, we systematically assess the effect of CALIPER in the management of IPF.

METHODS

A systematic review was conducted through a search of published studies in PubMed, Web of Science, Cochrane, Embase, Scopus, and CNKI databases from database inception through February 28, 2022. The methodological quality would be evaluated by using Methodological Index for Non-Randomized Studies (MINORS). Narrative synthesis summarized findings by participant characteristics, study design, and associations with outcomes.

RESULTS

Ten studies were included. They evaluated the relationship between CALIPER-derived parameters and pulmonary function test (PFT) and mortality. CALIPER-derived parameters showed a significant correlation with PFT and mortality. Two studies reported that CALIPER could be used to stratify outcomes.

CONCLUSION

CALIPER-derived parameters can be used to evaluate prognosis and mortality. CALIPER-derived parameters combined with composite physiologic index (CPI) or Gender-Age-Physiology (GAP) could help clinicians implement targeted management by refining prognostic stratification. However, research has been constrained by small number of retrospective investigations and sample sizes. Therefore, it is essential to design prospective controlled studies and establish the staging system by CALIPER-derived parameters and combining them with CPI, FVC, or GAP.

CLINICAL RELEVANCE STATEMENT

It is beneficial for clinic to provide objective, sensitive, and accurate indicators of disease progression. It also helps the clinic to develop individualized treatment plans based on the stage of disease progression and provides evaluation of efficacy in drug trials.

KEY POINTS

• Computer-Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER) is a quantitative CT analysis software that can be used to evaluate the progression of disease on CT. • The CALIPER-derived vessel-related structure shows great performance in the management of idiopathic pulmonary fibrosis. • CALIPER-derived parameters combined with composite physiologic index or Gender-Age-Physiology can be used to refine prognostic stratification.

NMDA receptor activation induces damage of alveolar type II cells and lung fibrogenesis through ferroptosis

Ferroptosis, a newly discovered type of regulated cell death, has been implicated in numerous human diseases. Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal interstitial lung disease with poor prognosis and limited treatment options. Emerging evidence has linked ferroptosis and glutamate-determined cell fate which is considered a new light on the etiology of pulmonary fibrosis. Here, we observed that N-methyl d-aspartate receptor (NMDAR) activation promoted cell damage and iron deposition in MLE-12 cells in a dose-, time-, and receptor-dependent manner. This mediated substantial Ca2+ influx, upregulated the expression levels of nNOS and IRP1, and affected intracellular iron homeostasis by regulating the expression of iron transport-related proteins (i.e., TFR1, DMT1, and FPN). Excessive iron load promoted the continuous accumulation of total intracellular and mitochondrial reactive oxygen species, which ultimately led to ferroptosis. NMDAR inhibition reduced lung injury and pulmonary fibrosis in bleomycin-induced mice. Bleomycin stimulation upregulated the expression of NMDAR1, nNOS, and IRP1 in mouse lung tissues, which ultimately led to iron deposition via regulation of the expression of various iron metabolism-related genes. NMDAR activation initiated the pulmonary fibrosis process by inducing iron deposition in lung tissues and ferroptosis of alveolar type II cells. Our data suggest that NMDAR activation regulates the expression of iron metabolism-related genes by promoting calcium influx, increasing nNOS and IRP1 expression, and increasing iron deposition by affecting cellular iron homeostasis, ultimately leading to mitochondrial damage, mitochondrial dysfunction, and ferroptosis. NMDAR activation-induced ferroptosis of alveolar type II cells might be a key event to the initiation of pulmonary fibrosis.

Omentin-1 induces mechanically activated fibroblasts lipogenic differentiation through pkm2/yap/pparγ pathway to promote lung fibrosis resolution

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease characterized by extensive extracellular matrix (ECM) deposition by activated myofibroblasts, which are specialized hyper-contractile cells that promote ECM remodeling and matrix stiffening. New insights on therapeutic strategies aimed at reversing fibrosis by targeting myofibroblast fate are showing promise in promoting fibrosis resolution. Previously, we showed that a novel adipocytokine, omentin-1, attenuated bleomycin (BLM)-induced lung fibrosis by reducing the number of myofibroblasts. Apoptosis, deactivation, and reprogramming of myofibroblasts are important processes in the resolution of fibrosis. Here we report that omentin-1 reverses established lung fibrosis by promoting mechanically activated myofibroblasts dedifferentiation into lipofibroblasts. Omentin-1 promotes myofibroblasts lipogenic differentiation by inhibiting dimerization and nuclear translocation of glycolytic enzymes pyruvate kinase isoform M2 (PKM2) and activation of the downstream Yes-associated protein (YAP) by increasing the cofactor fructose-1,6-bisphosphate (F1, 6BP, FBP). Moreover, omentin-1 activates proliferator-activated receptor gamma (PPARγ) signaling, the master regulator of lipogenesis, and promotes the upregulation of the lipogenic differentiation-related protein perilipin 2 (PLIN2) by suppressing the PKM2-YAP pathway. Ultimately, omentin-1 facilitates myofibroblasts transformation into the lipofibroblast phenotype, with reduced collagen synthesis and enhanced degradation properties, which are crucial mechanisms to clear the ECM deposition in fibrotic tissue, leading to fibrosis resolution. Our results indicate that omentin-1 targets mechanical signal accelerates fibrosis resolution and reverses established lung fibrosis by promoting myofibroblasts lipogenic differentiation, which is closely associated with ECM clearance in fibrotic tissue. These findings suggest that targeting mechanical force to promote myofibroblast lipogenic differentiation is a promising therapeutic strategy against persistent lung fibrosis.

The Role of Osteopontin in Respiratory Health and Disease

The biological functions of osteopontin (OPN) are diverse and specific to physiological and pathophysiological conditions implicated in inflammation, biomineralization, cardiovascular diseases, cellular viability, cancer, diabetes, and renal stone disease. We aimed to present the role of OPN in respiratory health and disease. OPN influences the immune system and is a chemo-attractive protein correlated with respiratory disease severity. There is evidence that OPN can advance the disease stage associated with its fibrotic, inflammatory, and immune functions. OPN contributes to eosinophilic airway inflammation. OPN can destroy the lung parenchyma through its neutrophil influx and fibrotic mechanisms, linking OPN to at least one of the two major chronic obstructive pulmonary disease phenotypes. Respiratory diseases that involve irreversible lung scarring, such as idiopathic pulmonary disease, are linked to OPN, with protein levels being overexpressed in individuals with severe or advanced stages of the disorders and considerably lower levels in those with less severe symptoms. OPN plays a significant role in lung cancer progression and metastasis. It is also implicated in the pathogenesis of pulmonary hypertension, coronavirus disease 2019, and granuloma generation.

Mannosylated polydopamine nanoparticles alleviate radiation- induced pulmonary fibrosis by targeting M2 macrophages and inhibiting the TGF-β1/Smad3 signaling pathway

Radiation-induced pulmonary fibrosis (RIPF), one type of pulmonary interstitial diseases, is frequently observed following radiation therapy for chest cancer or accidental radiation exposure. Current treatments against RIPF frequently fail to target lung effectively and the inhalation therapy is hard to penetrate airway mucus. Therefore, this study synthesized mannosylated polydopamine nanoparticles (MPDA NPs) through one-pot method to treat RIPF. Mannose was devised to target M2 macrophages in the lung through CD 206 receptor. MPDA NPs showed higher efficiency of penetrating mucus, cellular uptake and ROS-scavenging than original polydopamine nanoparticles (PDA NPs) in vitro. In RIPF mice, aerosol administration of MPDA NPs significantly alleviated the inflammatory, collagen deposition and fibrosis. The western blot analysis demonstrated that MPDA NPs inhibited TGF-β1/Smad3 signaling pathway against pulmonary fibrosis. Taken together this study provide a novel M2 macrophages-targeting nanodrugs through aerosol delivery for the prevention and targeted treatment for RIPF.

Prognostic role of CHA2DS2-VASc score for mortality risk assessment in non-advanced idiopathic pulmonary fibrosis: a preliminary observation

During the last decade, the CHA₂DS₂-VASc score has been used for stratifying the mortality risk in both atrial fibrillation (AF) and non-AF patients. However, no previous study considered this score as a prognostic indicator in non-AF patients with mild-to-moderate idiopathic pulmonary fibrosis (IPF). All consecutive non-AF patients with mild-to-moderate IPF, diagnosed between January 2016 and December 2018 at our Institution, entered this study. All patients underwent physical examination, blood tests, spirometry, high-resolution computed tomography and transthoracic echocardiography. CHA₂DS₂-VASc score, Gender-Age-Physiology (GAP) index and Charlson Comorbidity Index (CCI) were determined in all patients. Primary endpoint was all-cause mortality, while the secondary endpoint was the composite of all-cause mortality and rehospitalizations for all causes over mid-term follow-up. 103 consecutive IPF patients (70.7 ± 7.3 yrs, 79.6% males) were retrospectively analyzed. At the basal evaluation, CHA₂DS₂-VASc score, GAP index and CCI were 3.7 ± 1.6, 3.6 ± 1.2 and 5.5 ± 2.3, respectively. Mean follow-up was 3.5 ± 1.3 yrs. During the follow-up period, 29 patients died and 43 were re-hospitalized (44.2% due to cardiopulmonary causes). On multivariate Cox regression analysis, CHA₂DS₂-VASc score (HR 2.15, 95% CI 1.59-2.91) and left ventricular ejection fraction (LVEF) (HR 0.91, 95% CI 0.86-0.97) were independently associated with all-cause mortality in IPF patients. CHA₂DS₂-VASc score (HR 1.66, 95% CI 1.39-1.99) and LVEF (HR 0.94, 95% CI 0.90-0.98) also predicted the secondary endpoint in the same study group. CHA₂DS₂-VASc score > 4 was the optimal cut-off for predicting both outcomes. At mid-term follow-up, a CHA₂DS₂-VASc score > 4 predicts an increased risk of all-cause mortality and rehospitalizations for all causes in non-AF patients with mild-to-moderate IPF.

Is pulmonary fibrosis a precancerous disease?

Idiopathic pulmonary fibrosis (IPF) is the most common type of interstitial lung disease (ILD) characterized by a histopathological pattern of usual interstitial pneumonia with progressive fibrosis of the pulmonary epithelium. The incidence of IPF is increasing worldwide as the population ages and with that, there is a concomitant increase in the incidence of lung cancer in these patients who are living longer with the disease. The average length of time for lung cancer development following an IPF diagnosis is 3 years. Given the high prevalence of lung cancer among patients with pulmonary fibrosis, we wondered if pulmonary fibrosis could be classified as a precancerous disease. We provided support from the Pubmed published literature to investigate whether pulmonary fibrosis meets the five criteria of the National Cancer Institute's definition of premalignant conditions for classification as a precancerous disease. We found out pulmonary fibrosis meets the five criteria of the National Cancer Institute's definition of a premalignant condition and can be considered a precancerous disease. To identify early lung cancer in patients with pulmonary fibrosis, regular screening with HRCT and PET-CT scans is highly recommended for these patients.

Duvelisib attenuates bleomycin-induced pulmonary fibrosis via inhibiting the PI3K/Akt/mTOR signalling pathway

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease that seriously threatens the health of patients. The pathogenesis of IPF is still unclear, and there is a lack of effective therapeutic drugs. Myofibroblasts are the main effector cells of IPF, leading to excessive deposition of extracellular matrix (ECM) and promoting the progression of fibrosis. Inhibiting the excessive activation and relieving autophagy blockage of myofibroblasts is the key to treat IPF. PI3K/Akt/mTOR pathway plays a key regulatory role in promoting fibroblast activation and autophagy inhibition in lung fibrosis. Duvelisib is a PI3K inhibitor that can simultaneously inhibit the activities of PI3K-δ and PI3K-γ, and is mainly used for the treatment of relapsed/refractory chronic lymphocytic leukaemia (CLL) and small lymphocytic lymphoma tumour (SLL). In this study, we aimed to examine the effects of Duvelisib on pulmonary fibrosis. We used a mouse model of bleomycin-induced pulmonary fibrosis to evaluate the effects of Duvelisib on pulmonary fibrosis in vivo and further explored the potential pharmacological mechanisms of Duvelisib in lung fibroblasts in vitro. The in vivo experiments showed that Duvelisib significantly alleviated bleomycin-induced collagen deposition and improved pulmonary function. In vitro and in vivo pharmacological experiments showed that Duvelisib dose-dependently suppressed lung fibroblast activation and improved autophagy inhibition by inhibiting the phosphorylation of PI3K, Akt and mTOR. Our results indicate that Duvelisib can alleviate the severity of pulmonary fibrosis and provide potential drugs for the treatment of pulmonary fibrosis.

Idiopathic pulmonary fibrosis therapy development: a clinical pharmacology perspective

Drug development for idiopathic pulmonary fibrosis (IPF) has been challenging due to poorly understood disease etiology, unpredictable disease progression, highly heterogeneous patient populations, and a lack of robust pharmacodynamic biomarkers. Moreover, because lung biopsy is invasive and dangerous, making the extent of fibrosis as a direct longitudinal measurement of IPF disease progression unfeasible, most clinical trials studying IPF can only assess progression of fibrosis indirectly through surrogate measures. This review discusses current state-of-art practices, identifies knowledge gaps, and brainstorms development opportunities for preclinical to clinical translation, clinical populations, pharmacodynamic endpoints, and dose optimization strategies. This article highlights clinical pharmacology perspectives in leveraging real-world data as well as modeling and simulation, special population considerations, and patient-centric approaches for designing future studies.

The Efficacy and Safety of Herbal Medicine with Pirfenidone in the Treatment of Idiopathic Pulmonary Fibrosis: A Systematic Review

Although there were randomized control trials (RCTs) that showed the considerable efficacy of herbal medicine (HM) in idiopathic pulmonary fibrosis (IPF) and systematic reviews on the value of some herbs in the treatment of IPF, there have been no systematic reviews comparing the combined use of complex HM against pirfenidone monotherapy in IPF. This review evaluated the efficacy of parallel administration of HM and pirfenidone in IPF treatment. We conducted a systematic review of RCTs that compared pirfenidone monotherapy against pirfenidone combined administration with HM in IPF. We searched the EMBASE, CENTRAL, PubMed, and CNKI databases for relevant RCTs published before July 2021. Six RCTs were eligible for inclusion. Compared with the control group, a greater recovery or a smaller reduction in forced vital capacity (FVC) and, in general, a valid improvement in the St. George’s Respiratory Questionnaire was observed in the treatment group. However, it should be noted that the risk of bias of the included RCTs was high or unclear in most categories. In IPF treatment, HM administered with pirfenidone effectively protected pulmonary function and improved the quality of life. However, given the number and quality of the included studies, the evidence was not strong enough to draw definitive conclusions. Well-designed future RCTs are warranted to evaluate the impact of HM on IPF.

Promises and Challenges of Cell-Based Therapies to Promote Lung Regeneration in Idiopathic Pulmonary Fibrosis

The lung epithelium is constantly exposed to harmful agents present in the air that we breathe making it highly susceptible to damage. However, in instances of injury to the lung, it exhibits a remarkable capacity to regenerate injured tissue thanks to the presence of distinct stem and progenitor cell populations along the airway and alveolar epithelium. Mechanisms of repair are affected in chronic lung diseases such as idiopathic pulmonary fibrosis (IPF), a progressive life-threatening disorder characterized by the loss of alveolar structures, wherein excessive deposition of extracellular matrix components cause the distortion of tissue architecture that limits lung function and impairs tissue repair. Here, we review the most recent findings of a study of epithelial cells with progenitor behavior that contribute to tissue repair as well as the mechanisms involved in mouse and human lung regeneration. In addition, we describe therapeutic strategies to promote or induce lung regeneration and the cell-based strategies tested in clinical trials for the treatment of IPF. Finally, we discuss the challenges, concerns and limitations of applying these therapies of cell transplantation in IPF patients. Further research is still required to develop successful strategies focused on cell-based therapies to promote lung regeneration to restore lung architecture and function.

Impact of gastroesophageal reflux disease on idiopathic pulmonary fibrosis and lung transplant recipients

PURPOSE OF REVIEW

Idiopathic pulmonary fibrosis (IPF) is a prevalent subset of interstitial lung disease (ILD) that often progresses to require lung transplantation. Gastroesophageal reflux disease (GERD) is common in the IPF population, and GER-related micro-aspiration appears to be an important risk factor for IPF pathogenesis and for the deterioration of transplanted lung function.

RECENT FINDINGS

Many patients with IPF have elevated esophageal acid exposure on reflux testing despite having no or minimal symptoms. Studies on the effects of medical GERD therapy on IPF-related outcomes have had mixed results. Antireflux surgery is safe in appropriately selected IPF patients, and appears to have potential for slowing the decline of lung function. GERD can persist, improve or develop after lung transplantation, and the presence of GERD is associated with allograft injury and pulmonary function decline in lung transplant recipients.

SUMMARY

Clinicians should have a low threshold to assess for objective evidence of GERD in IPF patients. Antireflux surgery in IPF patients with GERD appears to improve lung function, but further studies are needed before surgical treatment can be recommended routinely in this setting. In lung transplant recipients, reflux testing after transplant is the most accurate way to guide GERD treatment decisions.

Inflammatory bowel disease and risk of idiopathic pulmonary fibrosis: A protocol for systematic review and meta-analysis

Introduction

Inflammatory bowel disease is a relapsing chronic gastrointestinal inflammatory disease. Idiopathic pulmonary fibrosis is a rare but serious extraintestinal pulmonary manifestation of inflammatory bowel disease. However, the relationship between these two conditions is unclear. Therefore, this study aims to elucidate this relationship through a systematic review and meta-analysis, focusing on the risk of idiopathic pulmonary fibrosis in patients with inflammatory bowel disease.

Methods

The systematic review will be outlined according to the Preferred Reporting Items for Systematic Review and Meta-Analyses Protocols and its extension statement for reporting systematic reviews incorporating network meta-analyses of healthcare interventions: checklist and explanations. Original articles published in any language will be searched in the following databases: PubMed, Web of Science, EMBASE, Google Scholar, and Ovid. Observational studies that reveal an association measure between idiopathic pulmonary fibrosis and inflammatory bowel disease will be included (cross sectional, cohort, and case-control trials). Two independent reviewers will be assigned to evaluate study quality using the Newcastle–Ottawa scale for assessing the quality of non-randomized studies in meta-analyses. Sensitivity analyses will be conducted based on the quality of included studies. All relevant studies will be assessed based on the study type, sample size, inflammatory bowel disease subtype, odds ratio, confidence interval, treatment strategy, and follow-up. The Grading of Recommendations Assessment, Development, and Evaluation approach will be used to rate the quality of the evidence.

Discussion

The results of this meta-analysis may show that patients with inflammatory bowel disease are at higher risk of developing idiopathic pulmonary fibrosis. This study will be the first meta-analysis to focus on the association between inflammatory bowel disease and idiopathic pulmonary fibrosis. Exploring the relationship between the two conditions may further enhance our understanding of the pathogenesis of inflammatory bowel disease and idiopathic pulmonary fibrosis and promote the development of related research fields.

Every road leads to Rome: therapeutic effect and mechanism of the extracellular vesicles of human embryonic stem cell-derived immune and matrix regulatory cells administered to mouse models of pulmonary fibrosis through different routes

Background

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal interstitial lung disease. Whether extracellular vesicles are effective in treating IPF and what is the optimal administrative route is not clear. Our previous studies have shown that immunity and matrix regulatory cells (IMRCs) derived from human embryonic stem cells can safely treat lung injury and fibrosis in mouse models, and its mechanism of action is related to the paracrine effect. In this study, we investigated the therapeutic effects of IMRC-derived extracellular vesicles (IMRC-EVs) on a bleomycin-induced pulmonary fibrosis mouse model and explored the optimal route of administration.

Methods

To study the biodistribution of IMRC-EVs after administration via different routes, NIR labeled-IMRC-EVs were delivered by intratracheal (IT) or intravenous (IV) route, and in vivo imaging was acquired at different time points. The therapeutic effects of IMRC-EVs delivered by different routes were analyzed by assessing histology, lung function, cytokines levels, and transcriptome profiling. RNA-seq of lung tissues was performed to investigate the mechanisms of EV treatment through IT or IV administrations.

Results

IMRC-EVs mainly reserved in the liver and spleen when administrated via IV route; and mainly retained in the lungs via the IT route. IMRC-EVs administrated via both routes demonstrated a therapeutic effect as attenuated pulmonary fibrosis, improved lung function, and histological parameters. Based on our RNA-seq results, different pathways may be affected by IMRC-EVs administrated via IT or IV routes. In addition, in vitro experiments showed that IMRC-EVs inhibited epithelial-to-mesenchymal transition induced by TGF-β.

Conclusion

IMRC-EVs administrated via IT or IV routes generate different biodistributions, but are both effective for the treatment of bleomycin-induced pulmonary fibrosis. The therapeutic mechanisms of IMRC-EVs administrated via different routes may be different.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02839-7.

6-Gingerol, a functional polyphenol of ginger, reduces pulmonary fibrosis by activating Sirtuin1

Pulmonary fibrosis in general is the final common outcome of various interstitial lung diseases. In recent years, the incidence of pulmonary fibrosis has been rising with poor prognosis. 6-gingerol is deemed as a functional polyphenol of ginger. The aim of the present study was to investigate the effect of 6-gingerol, on pulmonary fibrosis. Mice were randomly divided into four groups: control, bleomycin, bleomycin + 6-gingerol 100 mg/kg, bleomycin + 6-gingerol 250 mg/kg, and the survival rates of the groups were recorded. Pathological and fibrotic changes in the lungs were identified by H&E and Masson staining, respectively. The levels of hydroxyproline and protein deposited in lung tissues were then, respectively, determined by colorimetry and western blotting. Subsequently, the proportion of cells and inflammatory factors in the alveolar lavage fluid were estimated. Following the identification of the possibility of Sirtuin1 (SIRT1) in the pharmacological mechanism through molecular docking and western blotting, human embryonic lung fibroblasts MRC-5 were treated with TGF-β1 and SIRT1 inhibitor to study the role of SIRT1 in the regulatory effect of 6-gingerol. From the results, 6-gingerol was found to increase the survival rate of mice and reduce lung pathology and fibrosis in mice. And, it significantly reduced the levels of hydroxyproline and the proteins deposited in lung tissues. Moreover, the number of neutrophils, basophils, monocytes, and the levels of inflammatory factors in the alveolar lavage fluid were also reduced. SIRT1 inhibitor blocked the function of 6-gingerol to inhibit fibrosis. To sum up, 6-gingerol relieves pulmonary fibrosis via activating SIRT1. This finding expands the pharmacological effect of 6-gingerol, and it is expected to advance the development of treatments for pulmonary fibrosis.

Natural Product-Based Potential Therapeutic Interventions of Pulmonary Fibrosis

Pulmonary fibrosis (PF) is a disease-refractive lung condition with an increased rate of mortality. The potential factors causing PF include viral infections, radiation exposure, and toxic airborne chemicals. Idiopathic PF (IPF) is related to pneumonia affecting the elderly and is characterized by recurring scar formation in the lungs. An impaired wound healing process, defined by the dysregulated aggregation of extracellular matrix components, triggers fibrotic scar formation in the lungs. The potential pathogenesis includes oxidative stress, altered cell signaling, inflammation, etc. Nintedanib and pirfenidone have been approved with a conditional endorsement for the management of IPF. In addition, natural product-based treatment strategies have shown promising results in treating PF. In this study, we reviewed the recently published literature and discussed the potential uses of natural products, classified into three types-isolated active compounds, crude extracts of plants, and traditional medicine, consisting of mixtures of different plant products-in treating PF. These natural products are promising in the treatment of PF via inhibiting inflammation, oxidative stress, and endothelial mesenchymal transition, as well as affecting TGF-β-mediated cell signaling, etc. Based on the current review, we have revealed the signaling mechanisms of PF pathogenesis and the potential opportunities offered by natural product-based medicine in treating PF.

The Role of Extracellular Vesicles in Idiopathic Pulmonary Fibrosis Progression: An Approach on Their Therapeutics Potential

Idiopathic pulmonary fibrosis (IPF) is a fibrosing interstitial lung disease of unknown etiology. Different types of cells are involved in fibrogenesis, which is persistently physical and molecular stimulation, either directly or by interacting with bioactive molecules and extracellular vesicles (EVs). Current evidence suggests that EVs play an essential role in IPF development. EVs are released by a variety of cells, including fibroblasts, epithelial cells, and alveolar macrophages. In addition, EVs can transport bioactive molecules, such as lipids, proteins, and nucleic acids, which play a pivotal role in cellular communication. Several proposed mechanisms show that an acceptor cell can capture, absorb, or interact with EVs through direct fusion with the plasma membrane, ligand–receptor interaction, and endocytotic process, modifying the target cell. During fibrogenesis, the release of EVs is deregulated, increases the EVs amount, and the cargo content is modified. This alteration is closely associated with the maintenance of the fibrotic microenvironment. This review summarizes the current data on the participation of EVs secreted by the cells playing a critical role in IPF pathogenesis.

Chlorogenic acid: Potential source of natural drugs for the therapeutics of fibrosis and cancer

Fibrosis and cancer is described by some epidemiological studies as chronic stages of different disease conditions typically characterized by uncontrolled accumulation of extra-cellular matrix (ECM), thereby leading to inflammation of tissues and organ (lungs, heart, liver and kidney) dysfunction. It is highly prevalent, and contributes to increased mortality rate worldwide. Currently, the therapeutical approaches involving selected medications (bemcentinib, pirfenidone and nintedanib) obtained synthetically, and used in clinical practices for fibrosis and cancer management and treatment has shown to be unsatisfactorily, especially during progressive stages of the disease. With regards to finding a more potent, effective, and promising curative for fibrosis and cancer, there is need for continuous experimental studies universally. However, phytochemical constituents’ particularly phenolic compounds [Chlorogenic acid (CGA)] obtained from coffee, and coffee beans have been predominantly utilized in experimental studies, due to its multiple pharmacological properties against various disease forms. Considering its natural source alongside minimal toxicity level, CGA, a major precursor of coffee have gained considerable attention nowadays from researchers worldwide, owing to its wide, efficacious and beneficial action against fibrosis and cancer. Interestingly, the safety of CGA has been proven. Furthermore, numerous experimental studies have also deduced massive remarkable outcomes in the use of CGA clinically, as a potential drug candidate against treatment of fibrosis and cancer. In the course of this review article, we systematically discussed the beneficial contributions of CGA with regards to its source, absorption, metabolism, mechanistic effects, and molecular mechanisms against different fibrosis and cancer categorization, which might be a prospective remedy in the future. Moreover, we also highlighted CGA (in vitro and in vivo analytical studies) defensive effects against various disorders.

Differential Genomic Profile in TERT, DSP, and FAM13A Between COPD Patients With Emphysema, IPF, and CPFE Syndrome

Background: Genetic association studies have identified single nucleotide polymorphisms (SNPs) associated with lasting lung diseases such as Chronic Obstructive Pulmonary Disease (COPD) and Idiopathic Pulmonary Fibrosis (IPF), as well as the simultaneous presentation, known as Combined Pulmonary Fibrosis and Emphysema (CPFE) Syndrome. It is unknown if these diseases share genetic variants previously described in an independent way. This study aims to identify common or differential variants between COPD, IPF, and CPFE. Materials and methods: The association analysis was carried out through a case-control design in a Mexican mestizo population (n = 828); three patients' groups were included: COPD smokers (COPD-S, n = 178), IPF patients (n = 93), and CPFE patients (n = 16). Also, two comparison groups were analyzed: smokers without COPD (SWOC, n = 367) and healthy subjects belonging to the Mexican Pulmonary Aging Cohort (PAC, n = 174). Five SNPs in four genes previously associated to interstitial and obstructive diseases were selected: rs2609255 (FAM13A), rs2736100 (TERT), rs2076295 (DSP) rs5743890, and rs111521887 (TOLLIP). Genotyping was performed by qPCR using predesigned Taqman probes. Results: In comparing IPF vs. PAC, significant differences were found in the frequency of the rs260955 G allele associated with the IPF risk (OR = 1.68, p = 0.01). Also, the genotypes, GG of rs260955 (OR = 2.86, p = 0.01) and TT of rs2076295 (OR = 1.79, p = 0.03) were associated with an increased risk of IPF; after adjusting by covariables, only the rs260955 G allele remain significant (p = 0.01). For the CPFE vs. PAC comparison, an increased CPFE risk was identified since there is a difference in the rs2736100 C allele (OR = 4.02, p < 0.01; adjusted p < 0.01). For COPD-S, the rs2609255 TG genotype was associated with increased COPD risk after adjusting by covariables. Conclusion: The rs2736100 C allele is associated with decreased IPF risk and confers an increased risk for CPFE. Also, the rs2076295 TT genotype is associated with increased IPF risk, while the GG genotype is associated with CFPE susceptibility. The rs2609255 G allele and GG genotype are associated with IPF susceptibility, while the TG genotype is present in patients with emphysema.

Contraindications to the Initiation of Veno-Venous ECMO for Severe Acute Respiratory Failure in Adults: A Systematic Review and Practical Approach Based on the Current Literature

(1) Background: Extracorporeal membrane oxygenation (ECMO) is increasingly used for acute respiratory failure with few absolute but many relative contraindications. The provider in charge often has a difficult time weighing indications and contraindications to anticipate if the patient will benefit from this treatment, a decision that often decides life and death for the patient. To assist in this process in coming to a good evidence-based decision, we reviewed the available literature. (2) Methods: We performed a systematic review through a literature search of the MEDLINE database of former and current absolute and relative contraindications to the initiation of ECMO treatment. (3) Results: The following relative and absolute contraindications were identified in the literature: absolute-refusal of the use of extracorporeal techniques by the patient, advanced stage of cancer, fatal intracerebral hemorrhage/cerebral herniation/intractable intracranial hypertension, irreversible destruction of the lung parenchyma without the possibility of transplantation, and contraindications to lung transplantation; relative-advanced age, immunosuppressed patients/pharmacological immunosuppression, injurious ventilator settings > 7 days, right-heart failure, hematologic malignancies, especially bone marrow transplantation and graft-versus-host disease, SAPS II score ≥ 60 points, SOFA score > 12 points, PRESERVE score ≥ 5 points, RESP score ≤ -2 points, PRESET score ≥ 6 points, and "do not attempt resuscitation" order (DN(A)R status). (4) Conclusions: We provide a simple-to-follow algorithm that incorporates absolute and relative contraindications to the initiation of ECMO treatment. This algorithm attempts to weigh pros and cons regarding the benefit for an individual patient and hopefully assists caregivers to make better, informed decisions.

Endobronchial autologous bone marrow-mesenchymal stromal cells in idiopathic pulmonary fibrosis: a phase I trial

Rationale

Idiopathic pulmonary fibrosis (IPF) has a dismal prognosis. Mesenchymal stromal cells (MSCs) have shown benefit in other inflammatory diseases.

Objectives

To evaluate the safety and feasibility of endobronchial administration of bone marrow autologous MSCs (BM-MSC) in patients with mild-to-moderate IPF.

Methods

A phase I multicentre clinical trial (ClinicalTrials.gov NCT01919827) with a single endobronchial administration of autologous adult BM-MSCs in patients diagnosed with mild-to-moderate IPF. In a first escalating-dose phase, three patients were included sequentially in three dose cohorts (10×10⁶, 50×10⁶ and 100×10⁶ cells). In a second phase, nine patients received the highest tolerated dose. Follow-up with pulmonary function testing, 6-min walk test and St George's Respiratory Questionnaire was done at 1, 2, 3, 6 and 12 months, and with computed tomography at 3, 6 and 12 months.

Results

21 bone marrow samples were obtained from 17 patients. Three patients were excluded from treatment due to chromosome aberrations detected in MSCs after culture, and one patient died before treatment. Finally, 13 patients received the BM-MSC infusion. No treatment-related severe adverse events were observed during follow-up. Compared to baseline, the mean forced vital capacity showed an initial decline of 8.1% at 3 months. The number of patients without functional progression was six (46%) at 3 months and three (23%) at 12 months.

Conclusions

The endobronchial infusion of BM-MSCs did not cause immediate serious adverse events in IPF patients, but a relevant proportion of patients suffered clinical and/or functional progression. Genomic instability of BM-MSCs during culture found in three patients may be troublesome for the use of autologous MSCs in IPF patients.

Endobronchial autologous mesenchymal stromal cells (MSCs) did not cause direct serious adverse events in IPF patients. However, significant progression was seen in seven out of 13 patients. Genomic instability of autologous MSCs may limit use in IPF.https://bit.ly/39akv7z

How We Do It: Managing Cough in Idiopathic Pulmonary Fibrosis

In many studies, more than one-half of patients with idiopathic pulmonary fibrosis (IPF) endorse cough. In IPF (as in other conditions), when chronic, cough may be frustrating and lead to significant impairments in quality of life. In patients with IPF, comorbid conditions such as gastroesophageal reflux can cause or contribute to cough; when stemming from IPF itself, chronic cough likely arises from multiple mechanisms including mechanical and neurosensory changes. In this article, we review our approach at attempting to identify causes of chronic cough in patients with IPF; these include gastroesophageal reflux disease or upper airway cough syndrome and IPF itself. We cursorily summarize the current evidence for the treatment of chronic cough in IPF, briefly review data on the treatment of unexplained chronic cough and extrapolate it to the treatment of refractory cough in IPF, but we focus our attention on our approaches to evaluation and management, recognizing that some may not be supported by a robust cache of data.

Occupational exposures and idiopathic pulmonary fibrosis

PURPOSE OF REVIEW

A recent meta-analysis of data from international case-control studies reports a population attributable fraction of 16% for occupational factors in the cause of idiopathic pulmonary fibrosis (IPF). Smoking, genetic factors and other prevalent diseases only partly explain IPF, and so this review aims to summarize recent progress in establishing which occupational exposures are important in cause.

RECENT FINDINGS

IPF is a rare disease, although it is the commonest idiopathic interstitial pneumonia. Epidemiological study suggests that incidence of IPF is increasing, particularly in older men. There are significant associations with IPF and occupational exposures to organic dust, including livestock, birds and animal feed, metal dust, wood dust and silica/minerals. Estimates of effect vary between studies, and are influenced by the distribution of employment, study design and case definition. Inhalation of asbestos fibres is a known cause of usual interstitial pneumonia (as seen histologically in IPF), though there are significant linear relationships between asbestos consumption, and mortality from both IPF and mesothelioma, leading to the hypothesis that low-level asbestos exposure may cause IPF.

SUMMARY

Research must focus on exposure-response relationships between asbestos and other occupational inhaled hazards, and IPF. Funding bodies and policy makers should acknowledge the significant occupational burden on IPF.

Characterization of the heterogeneity of endothelial cells in bleomycin-induced lung fibrosis using single-cell RNA sequencing

The loss of normal alveolar capillary and deregulated angiogenesis occurs simultaneously in idiopathic pulmonary fibrosis (IPF); however the contributions of specific endothelial subpopulations in the development of pulmonary fibrosis are poorly understood. Herein, we perform single-cell RNA sequencing to characterize the heterogeneity of endothelial cells (ECs) in bleomycin (BLM)-induced lung fibrosis in rats. One subpopulation, characterized by the expression of Nos3 and Cav1, is mostly distributed in non-fibrotic lungs and also highly expresses genes related to the “response to mechanical stimulus” and “lung/heart morphogenesis” processes. Another subpopulation of ECs expanded in BLM-treated lungs, characterized by Cxcl12, is observed to be closely related to the pro-fibrotic process in the transcriptome data, such as “regulation of angiogenesis,” “collagen binding,” and “chemokine activity,” and spatially localized to BLM-induced neovascularization. Using CellPhoneDB software, we generated a complex cell–cell interaction network, which predicts the potential roles of EC subpopulations in recruiting monocytes, inducing the proliferation of fibroblasts and promoting the production and remolding of the extracellular matrix (ECM). Taken together, our data demonstrate the high degree of heterogeneity of ECs in fibrotic lung and it is proposed that the interaction between ECs, macrophages, and stromal cells contributes to pathologic IPF.

TGF‑β1: Gentlemanly orchestrator in idiopathic pulmonary fibrosis (Review)

Idiopathic pulmonary fibrosis (IPF) is a worldwide disease characterized by the chronic and irreversible decline of lung function. Currently, there is no drug to successfully treat the disease except for lung transplantation. Numerous studies have been devoted to the study of the fibrotic process of IPF and findings showed that transforming growth factor-β1 (TGF-β1) plays a central role in the development of IPF. TGF-β1 promotes the fibrotic process of IPF through various signaling pathways, including the Smad, MAPK, and ERK signaling pathways. There are intersections between these signaling pathways, which provide new targets for researchers to study new drugs. In addition, TGF-β1 can affect the fibrosis process of IPF by affecting oxidative stress, epigenetics and other aspects. Most of the processes involved in TGF-β1 promote IPF, but TGF-β1 can also inhibit it. This review discusses the role of TGF-β1 in IPF.

[Differential mRNA expression in C57BL/6 mice with bleomycin-induced pulmonary fibrosis and its association with LncRNA co-expression network]

OBJECTIVE

To study the changes in mRNA and long non-coding RNA (lncRNA) expression profiles in a mouse model of bleomycin-induced lung fibrosis and identify lung fibrosis-related mRNA for coding-noncoding coexpression (CNC) bioinformatics analysis of the differential lncRNAs.

METHODS

Lung fibrosis was induced by intratracheal injection of bleomycin in 10 C57BL/6 mice and another 10 mice with intratracheal injection of saline served as the control group. Lung tissues were harvested from the mice at 14 days after the injections and lung fibrosis was assessed using Masson and HE staining. LncRNA chip technology was used to screen the differentially expressed mRNAs and lncRNAs in mice with lung fibrosis, and GO and KEGG pathway analyses of the differential mRNAs were performed using NCBI database and UCSC database to identify possible fibrosis-related mRNAs, which were validated by qRT-PCR to construct a coding and non-coding co- expression network with the differential lncRNAs.

RESULTS

Compared with the control mice, the mice with intratracheal injection of bleomycin showed obvious lung fibrosis. The results of gene chip analysis showed that 127 mRNAs were upregulated and 184 mRNAs were down-regulated in the model group as compared with the control group. GO and pathway analysis suggested that the differentially expressed genes participated mainly in immune response, cell differentiation, and cytoskeletons; the involved signal pathways were associated mainly with cytokine and cytokine receptor interaction and chemokine signal transduction. Bioinformatics analysis identified a significant coexpression network between the fibrosisrelated mRNA and the differentially expressed lncRNA.

CONCLUSIONS

In mice with lung fibrosis, the differential expressions of fibrosis-related mRNAs in the lung tissues are closely correlated with the co- expressions of a large number of differential lncRNAs, which points to a new direction for investigation of the pathogenesis of pulmonary fibrosis.

Connective Tissue Disease Related Interstitial Lung Disease

Patients with connective tissue diseases may have pulmonary involvement, including interstitial lung disease. Various patterns of interstitial lung disease have been classically described in certain connective tissue diseases. It is now recognized that there is significant overlap between patterns of interstitial lung disease observed in the various connective tissue diseases. Differentiating idiopathic from connective tissue disease-related interstitial lung disease is challenging but of clinical importance. New concepts in the diagnosis of connective tissue disease related interstitial lung disease may prove useful in making the diagnosis.

Idiopathic Pulmonary Fibrosis Registry China study (PORTRAY): protocol for a prospective, multicentre registry study

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal lung disease characterised by a fibrotic histological pattern found in usual interstitial pneumonia. Its causes, pathogenesis, clinical phenotype and molecular mechanisms are poorly defined. Large-scale, multicentre studies are warranted to better understand IPF as a disease in China, its associated risk factors, clinical characteristics, diagnosis, disease progression and treatment.

METHODS AND ANALYSIS

The Idiopathic Pulmonary Fibrosis Registry China Study (PORTRAY) is a prospective, multicentre registry study of patients with IPF in China. Eight hundred patients will be enrolled over a 36-month period and followed for at least 3 years to generate a comprehensive database on baseline characteristics and various follow-up parameters including patient-reported outcomes. Biological specimens will also be collected from patients to develop a library of blood, bronchoalveolar lavage fluid and lung biopsy samples, to support future research. As of 15 December 2019, 204 patients from 19 large medical centres with relatively high IPF diagnosis and treatment rates had been enrolled. Patient characteristics will be presented using descriptive statistics. The Kaplan-Meier method will be used for survival analyses. Repeated measures will be used to compare longitudinal changes in lung function, imaging and laboratory tests. Results following analysis have been projected to be available by July 2025.

ETHICS AND DISSEMINATION

The study protocol was reviewed and approved by the Institutional Review Board from all the study sites currently recruiting patients. Study results will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03666234.

Senotherapeutics: Targeting senescence in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal chronic lung disease characterized by progressive scarring of the lung tissue, leading to respiratory failure. There is no cure for IPF, and current anti-fibrotic treatments modestly arrest its further progression. IPF prevalence and incidence increase with age, which is a recognized risk factor. Intense clinical and basic research over the last fifteen years has shown that hallmarks of accelerated aging are present in the lungs of patients with IPF. Different cell types in IPF lungs exhibit premature hallmarks of aging, including telomere attrition and cellular senescence. In this Review, we discuss recent insights into the mechanisms behind these age-related alterations and their contribution to the development of lung fibrosis. We focus on the genetic and molecular basis of telomere attrition in alveolar type II epithelial cells, which promote cellular senescence and lung fibrosis. Mechanistically, senescent cells secrete pro-fibrotic factors that activate scar-forming myofibroblasts. Ultimately, senescent alveolar epithelial cells lose their regenerative capacity, impeding fibrosis resolution. In addition, mitochondrial dysfunction is strongly associated with the appearance of senescent epithelial cells and senescent myofibroblasts in IPF, which persist in the fibrotic tissue by adapting their metabolic pathways and becoming resistant to apoptosis. We discuss emerging novel therapeutic strategies to treat IPF by targeting cellular senescence with the so-called senotherapeutics.

Reversal of bleomycin-induced rat pulmonary fibrosis by a xenograft of human umbilical mesenchymal stem cells from Wharton's jelly

Pulmonary fibrosis (PF) is a progressive and irreversible condition with various causes, and no effective treatment has been found to rescue fibrotic lungs. Successful recovery from PF requires inhibiting inflammation, promoting collagen degradation and stimulating alveolar regeneration. Human umbilical mesenchymal stem cells (HUMSCs) not only regulate immune responses but also synthesize and release hyaluronan to improve lung regeneration. This study investigated the feasibility of HUMSC engraftment into rats with bleomycin (BLM)-induced PF to explore HUMSC therapeutic effects/outcomes.

Methods: A unique BLM-induced left-lung-dominated PF animal model was established. Rats were transplanted with low-dose (5×10⁶) or high-dose (2.5×10⁷) HUMSCs on Day 21 after BLM injection. Combinations in co-culture of pulmonary macrophages, fibroblasts, HUMSCs treated with BLM and the same conditions on alveolar epithelia versus HUMSCs were evaluated.

Results: Rats with high-dose HUMSC engraftment displayed significant recovery, including improved blood oxygen saturation levels and respiratory rates. High-dose HUMSC transplantation reversed alveolar injury, reduced cell infiltration and ameliorated collagen deposition. One month posttransplantation, HUMSCs in the rats' lungs remained viable and secreted cytokines without differentiating into alveolar or vascular epithelial cells. Moreover, HUMSCs decreased epithelial-mesenchymal transition in pulmonary inflammation, enhanced macrophage matrix-metallopeptidase-9 (MMP-9) expression for collagen degradation, and promoted toll-like receptor-4 (TLR-4) expression in the lung for alveolar regeneration. In coculture studies, HUMSCs elevated the MMP-9 level in pulmonary macrophages, released hyaluronan into the medium and stimulated the TLR-4 quantity in the alveolar epithelium.

Principal Conclusions: Transplanted HUMSCs exhibit long-term viability in rat lungs and can effectively reverse rat PF.