Circulating KL-6 predicts the outcome of rapidly progressive idiopathic pulmonary fibrosis

Prognostic value of serial serum KL-6 measurements in patients with idiopathic pulmonary fibrosis

BACKGROUND

The prognostic significance of serial measurements of serum KL-6 levels in patients with idiopathic pulmonary fibrosis (IPF) is unclear; hence, it was assessed in this study.

METHODS

Medical records of 66 patients with IPF, who were not treated with pirfenidone prior to enrollment, were retrospectively reviewed for information on clinical progress, forced vital capacity (FVC), survival, and serum KL-6 levels. We assessed initial serum levels of KL-6, serial changes in serum KL-6 levels, yearly decline in FVC (ΔFVC), and the rate of decline (%ΔFVC).

RESULTS

Patients with increased serum KL-6 levels during follow-up had a significantly steeper decline in ΔFVC than those with no KL-6 increase (-201 vs. -50.7ml/year; p=0.0001). Patients with both initial serum KL-6 ≥1000U/ml and serial increases in serum KL-6 had the steepest decline, while those with both initial serum KL-6 <1000ml and no serial increases in KL-6 had the least decline in ΔFVC and %ΔFVC. Relative to the non-increased KL-6 group, survival in the increased KL-6 group tended to be poorer (p=0.0530). Patients with both initial serum KL-6 values <1000U/ml and no serial increase in KL-6 had more favorable prognoses than those with serial increases in KL-6 or initial serum KL-6 values ≥1000U/ml (p<0.0044). Prognosis was significantly poorer in patients with serial KL-6 changes >51.8U/ml/year than in those with serial KL-6 changes <51.8U/ml/year (p=0.0009).

CONCLUSION

Thus, serial serum KL-6 measurements can be useful for assessing prognosis in patients with IPF.

A cohort study of the acute and chronic respiratory effects of toner exposure among handlers: a longitudinal analyses from 2004 to 2013

This study examines the acute and chronic respiratory effects of toner exposure based on markers for interstitial pneumonia, oxidative stress and pulmonary function tests. A total of 112 subjects working in a Japanese toner and photocopier manufacturing company participated in this study in 2004. We annually conducted personal exposure measurements, pulmonary function tests, chest X-ray examinations, biomarkers, and questionnaires on respiratory symptoms to the subjects. We report in this paper the results of the analysis of combined annual survey point data from 2004 to 2008 and data from three annual survey points, 2004, 2008, and 2013. During these survey periods, we observed that none of subjects had a new onset of respiratory disease or died of such a disease. In both the analyses, there were no significant differences in each biomarker and pulmonary function tests within the subjects, nor between a toner-handling group and a non-toner-handling group, except for a few results on pulmonary function tests. The findings of this study suggest that there were no acute and chronic respiratory effects of toner exposure in this cohort group, although the number of subjects was small and the level of toner exposure in this worksite was low.

Plasma Leptin Is Elevated in Acute Exacerbation of Idiopathic Pulmonary Fibrosis

Background. The natural history of idiopathic pulmonary fibrosis (IPF) is very complex and unpredictable. Some patients will experience acute exacerbation (AE) and fatal outcomes. Methods. The study included 30 AE-IPF patients, 32 stable IPF (S-IPF) patients, and 12 healthy controls. We measured the plasma concentrations of leptin and KL-6. Simple correlation was used to assess associations between leptin and other variables. Plasma leptin levels were compared between AE-IPF and S-IPF subjects, decedents, and survivors. Kaplan-Meier curves were used to display survival and Cox proportional hazards regression was used to examine risk factors for survival. Results. In subjects with AE-IPF, plasma leptin was significantly greater than in subjects with S-IPF (p = 0.0003) or healthy controls (p < 0.0001). Plasma leptin was correlated with BMI, KL-6, LDH, CRP, and PaO₂/FiO₂ (p = 0.007; p = 0.005; p = 0.003; p = 0.033; and p = 0.032, resp.). Plasma leptin was significantly greater in 33 decedents than in the 23 survivors (p = 0.007). Multivariate Cox regression analysis showed leptin (>13.79 ng/mL) was an independent predictor of survival (p = 0.004). Conclusions. Leptin could be a promising plasma biomarker of AE-IPF occurrence and predictor of survival in IPF patients.

State-of-the-Art Imaging of the Lung for Connective Tissue Disease (CTD)

Involvement of the respiratory system is common in connective tissue diseases (CTDs), and the resultant lung injury can affect every part of the lung: the pleura, alveoli, interstitium, vasculature, lymphatic tissue, and large and/or small airways. Most of the parenchymal manifestations of CTD are similar to those found in interstitial lung diseases (ILDs), especially idiopathic interstitial pneumonias, and can be classified using the same system. Although there is some overlap, each CTD is associated with a characteristic pattern of pulmonary involvement. For this reason, thin-section CT as well as pulmonary function tests and serum markers are utilized for diagnosis, disease severity assessment, and therapeutic efficacy evaluation of ILD associated with CTD. In addition, newly developed pulmonary magnetic resonance imaging (MRI) procedures have been recommended as useful alternative imaging options for patients with CTD. This review article will (1) address radiological findings for chest radiography and conventional or thin-section CT currently used for six major types of CTD, rheumatoid arthritis, scleroderma (progressive systemic sclerosis), polymyositis/dermatomyositis, systemic lupus erythematosus, Sjögren syndrome and mixed connective tissue disease; (2) briefly deal with radiation dose reduction for thin-section CT examination; and (3) discuss clinically applicable or state-of-the-art MR imaging for CTD patients.

Transforming growth factor-beta 1 in humidifier disinfectant-associated children's interstitial lung disease

BACKGROUND

Humidifier disinfectant-associated children's interstitial lung disease has an unpredictable clinical course with a high morbidity and mortality.

OBJECTIVES

To evaluate the differences in clinical findings between survivors and non-survivors of humidifier disinfectant-associated children's interstitial lung disease. To evaluate dynamic changes in serum cytokines related to inflammation and fibrosis in lung injury, and to determine whether these changes are predictive of survival in this disease.

METHODS

We evaluated 17 children with humidifier disinfectant-associated children's interstitial lung disease, from whom serum samples were obtained weekly during hospitalization. The severity of chest tomographic and lung pathologic findings was scored. Levels of several cytokines were measured in the serial serum samples.

RESULTS

Seven of the 17 children were survivors. Compared to survivors, non-survivors had greater ground-glass attenuation on follow-up chest tomography, higher admission neutrophil counts, and more macrophages on pathologic findings. Transforming growth factor-beta 1 persisted at an elevated level (1,000-1,500 pg/ml) in survivors, whereas it decreased abruptly in non-survivors. At the time of this decrease, non-survivors had clinical worsening of their respiratory failure. Transforming growth factor-beta 1 was positively correlated with PaO2 /FiO2 (r = 0.481, P < 0.0001).

CONCLUSIONS

Non-survivors exhibited more inflammatory clinical findings than survivors. Transforming growth factor-beta 1 remained elevated in survivors, suggesting that it affected the clinical course of humidifier disinfectant-associated children's interstitial lung disease. The prognosis of this lung disease may depend more on controlling excessive inflammation and repairing damaged lung than on fibrosis, and transforming growth factor-beta 1 may play a key role in this process.

Specific Serum Markers of IPF

Idiopathic pulmonary fibrosis (IPF) is defined as a specific form of chronic, progressive, fibrosing interstitial pneumonia of unknown cause. It is characterized by the progressive worsening of lung function and has a poor prognosis (median survival is approximately 3 years). However, the clinical course of disease shows considerable individual variability. Therefore, it is important to monitor the clinical course and to predict prognosis for optimal therapy. Serum biomarkers are both less invasive and reproducible diagnostic tools. Useful biomarkers for patients with IPF are strongly coveted; however, to date, there are no biomarkers that are globally known. In Japan, surfactant protein (SP)-A, SP-D, and KL-6 are commonly used as serum markers of interstitial pneumonia, including IPF, in the clinical setting, and empirical data has been accumulated over 10 years. SP-A and SP-D are hydrophilic proteins and members of the collectin family. These collectins have been shown to function as host defense lectins in the lung. KL-6 is a high molecular weight glycoprotein and now classified as a human MUC1 mucin protein. These three proteins are mainly synthesized by alveolar type II cells. The mechanisms of increase for these protein levels in sera of patients with IPF are probably a combination of a loss of epithelial integrity due to injury and an increased mass of type II cells due to hyperplasia. It has been revealed that those proteins are useful for monitoring the clinical course and predicting prognosis as well as for the diagnosis of IPF. In this review article, the molecular structures and biological functions of these biomarkers are outlined, and we discuss the clinical application of these biomarkers for patients with IPF.

Personalized medicine in idiopathic pulmonary fibrosis: facts and promises

PURPOSE OF REVIEW

In this article, we summarize and discuss the most recent literature on personalized medicine in idiopathic pulmonary fibrosis (IPF), a chronic progressive and almost invariably lethal disease of unknown cause. This review is timely as major advances in our understanding of disease pathobiology and improvements in molecular techniques have recently led to the identification of potential surrogates of diagnosis, prognosis and response to treatment.

RECENT FINDINGS

The most promising and advanced candidate biomarkers are presented based on their proposed mechanistic pathways (e.g. alveolar epithelial cell dysfunction, immune dysregulation, microbiome, extracellular matrix remodeling and fibroproliferation, epigenetic markers and metabolomics). Recent data suggest that components of the immune system may contribute to the development of IPF. A potential role for infections as a cofactor in disease development and progression or as a trigger in disease exacerbation has also recently been proposed.

SUMMARY

Clinical management of IPF is unsatisfactory because of limited availability of truly effective therapies, lack of accurate predictors of disease behavior and absence of simple short-term measures of therapeutic response. A number of putative biomarkers have been identified in patients with IPF, although none has been validated to the standard necessary for their use in either therapeutic trials or clinical practice. Currently, ongoing prospective longitudinal studies will hopefully permit such validation.

Efficacy and safety of inhaled N-acetylcysteine in idiopathic pulmonary fibrosis: A prospective, single-arm study

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with few treatment options. The efficacy of N-acetylcysteine in patients with IPF remains controversial. The aim of this research was to investigate the efficacy of inhaled N-acetylcysteine.

METHODS

This study was designed as a single-center, single-arm, prospective clinical trial. Each patient who had IPF received 352.4mg of inhaled N-acetylcysteine twice daily.

RESULTS

In total, 28 patients were enrolled. The mean values of the respiratory function parameters at the initiation of therapy were as follows: forced vital capacity (FVC), 2.27L and %FVC, 76.2%. The mean change in FVC during 26 weeks prior to the inhaled N-acetylcysteine therapy was -170mL, a significant decrease (p=0.019). The mean change in FVC during 26 weeks after the initiation of inhaled N-acetylcysteine therapy was -70mL (p=0.06). When the patients were classified into two groups according to the degree of decline in FVC (≥100mL vs. <100mL) during the 26-week period prior to the initiation of therapy, inhaled N-acetylcysteine showed a greater efficacy in attenuating FVC decline in the ≥100-mL group than in the <100-mL group.

CONCLUSIONS

Inhaled N-acetylcysteine therapy was effective in patients with mild-to-moderate IPF and was more beneficial in patients who had greater declines in FVC before the initiation of therapy. (UMIN title: Efficacy and safety of inhaled N-acetylcysteine in idiopathic pulmonary fibrosis, UMIN000016706, 2015/03/04.).

Models of disease behavior in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis is a diffuse parenchymal lung disease of unknown cause. The natural history of disease can vary considerably, making it difficult to predict the clinical trajectory for an individual patient. Accurate prognostication is desirable for clinical management as well as for cohort enrichment in clinical trials of therapeutics. Clinical and biomarker models of disease behavior have been developed to improve prognostication in idiopathic pulmonary fibrosis, with moderate predictive capabilities. Integrated prediction models that combine both clinical and biomarker variables will improve prognostication for patients and improved cohort enrichment strategies for clinical trials. This goal may be best achieved through collaborative patient registries with prospectively collected biological samples that allow for characterization of disease behavior in idiopathic pulmonary fibrosis.

The Ratio KL-6 to SLX in Serum for Prediction of the Occurrence of Drug-Induced Interstitial Lung Disease in Lung Cancer Patients with Idiopathic Interstitial Pneumonias Receiving Chemotherapy

We retrospectively evaluated whether the ratio KL-6 to SLX in serum (K/S ratio) before chemotherapy was a predictor for the occurrence of drug-induced interstitial lung disease (D-ILD) in lung cancer patients with idiopathic interstitial pneumonias (IIPs). D-ILD occurred in 8 of 20 IIPs-positive cases and in 14 of 100 IIPs-negative cases (40 vs. 14%, p = .015). In IIPs-positive cases, the high K/S ratio (>20) before first-line chemotherapy had a tendency to increase the risk of D-ILD (p = .085). Serum K/S ratio may be a useful predictor for the occurrence of D-ILD in lung cancer patients with IIPs.

Molecular classification of idiopathic pulmonary fibrosis: personalized medicine, genetics and biomarkers

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive fibrotic lung disease associated with high morbidity and poor survival. Characterized by substantial disease heterogeneity, the diagnostic considerations, clinical course and treatment response in individual patients can be variable. In the past decade, with the advent of high-throughput proteomic and genomic technologies, our understanding of the pathogenesis of IPF has greatly improved and has led to the recognition of novel treatment targets and numerous putative biomarkers. Molecular biomarkers with mechanistic plausibility are highly desired in IPF, where they have the potential to accelerate drug development, facilitate early detection in susceptible individuals, improve prognostic accuracy and inform treatment recommendations. Although the search for candidate biomarkers remains in its infancy, attractive targets such as MUC5B and MPP7 have already been validated in large cohorts and have demonstrated their potential to improve clinical predictors beyond that of routine clinical practices. The discovery and implementation of future biomarkers will face many challenges, but with strong collaborative efforts among scientists, clinicians and the industry the ultimate goal of personalized medicine may be realized.

Discovery and validation of extracellular/circulating microRNAs during idiopathic pulmonary fibrosis disease progression

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrosing interstitial lung disease of unknown etiology that is currently untreatable. In this study we aim to characterize the potential of extracellular/circulating microRNAs (miRNAs) in serum as biomarkers for IPF.

METHODS

Total serum RNAs were isolated from serum from healthy control subjects (n=12), rapid progressive (n=12) and slowly progressive IPF patients (n=12). Serum RNA was analyzed by using TaqMan microRNA assays containing probes for 366 human miRNAs, and selected findings were validated with quantitative RT-PCR. Target prediction and pathway analysis on the significant differential miRNAs were performed using DIANA-mirPath.

RESULTS

We found 47 significantly differentially expressed serum miRNAs (p<0.05) in rapid progressive or slowly progressive IPF patients compared to healthy controls, including 21 up-regulated miRNAs and 26 down-regulated miRNAs. Bioinformatic analysis by DIANA-mirPath demonstrated that 53 KEGG biological processes were significantly enriched (p < 0.05, FDR corrected) among differentially expressed serum miRNAs, including TGF-beta signaling pathway (p < 0.0001), MAPK signaling pathway (p < 0.0001), PI3K-Akt signaling pathway (p < 0.0001), Wnt signaling pathway (p < 0.0001), HIF-1 signaling pathway (p < 0.0001), Regulation of actin cytoskeleton (p < 0.0001), Jak-STAT signaling pathway (p < 0.0001), Notch signaling pathway (p < 0.0001), and Cytokine-cytokine receptor interaction (p = 0.0062). We further validated six miRNAs (miR-21, miR-199a-5p, miR-200c, miR-31, let-7a, and let-7d) for further validation using an independent cohort of 20 rapid progressive IPF, 24 slowly progressive IPF patients and 20 healthy controls. In agreement with the preliminary data from miRNA assay, miR-21, miR-199a-5p, and miR-200c were significantly increased in serums of IPF patients while miR-31, let-7a, and let-7d were significantly under expressed in serums of IPF patients compared to healthy controls.

CONCLUSIONS

These studies demonstrated that extracellular/circulating miRNAs in serum could be potentially served as novel regulators influencing disease progression of IPF.

Histological evolution of pleuroparenchymal fibroelastosis

AIMS

To investigate the histological evolution in the development of pleuroparenchymal fibroelastosis (PPFE).

METHODS AND RESULTS

We examined four patients who had undergone surgical lung biopsy twice, or who had undergone surgical lung biopsy and had been autopsied, and in whom the histological diagnosis of the first biopsy was not PPFE, but the diagnosis of the second biopsy or of the autopsy was PPFE. The histological patterns of the first biopsy were cellular and fibrotic interstitial pneumonia, cellular interstitial pneumonia (CIP) with organizing pneumonia, CIP with granulomas and acute lung injury in cases 1, 2, 3, and 4, respectively. Septal elastosis was already present in the non-specific interstitial pneumonia-like histology of case 1, but a few additional years were necessary to reach consolidated subpleural fibroelastosis. In case 3, subpleural fibroelastosis was already present in the first biopsy, but only to a small extent. Twelve years later, it was replaced by a long band of fibroelastosis. The septal inflammation and fibrosis and airspace organization observed in the first biopsies were replaced by less cellular subpleural fibroelastosis within 3-12 years.

CONCLUSIONS

Interstitial inflammation or acute lung injury may be an initial step in the development of PPFE.

New treatment and markers of prognosis for idiopathic pulmonary fibrosis: lessons learned from translational research

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease with increasing prevalence, high mortality rates and poor treatment options. The diagnostic process is complex and often requires an interdisciplinary approach between different specialists. Information gained over the past 10 years of intense research resulted in improved diagnostic algorithms, a better understanding of the underlying pathogenesis and the development of new therapeutic options. Specifically, the change from the traditional concept that viewed IPF as a chronic inflammatory disorder to the current belief that is primarily resulting from aberrant wound healing enabled the identification of novel treatment targets. This increased the clinical trial activity dramatically and resulted in the approval of the first IPF-specific therapy in many countries. Still, the natural history and intrinsic behavior of IPF are very difficult to predict. There is an urgent need for new therapies and also for development and validation of prognostic markers that predict disease progression, survival and also response to antifibrotic drugs. This review provides an up to date summary of the most relevant clinical trials, novel therapeutic drug targets and outlines a spectrum of potential prognostic biomarkers for IPF.

Clinical and laboratory features of fatal rapidly progressive interstitial lung disease associated with juvenile dermatomyositis

OBJECTIVE

Rapidly progressive interstitial lung disease (RP-ILD) is a rare but potentially fatal complication of JDM. The aim of this study was to establish markers for the prediction and early diagnosis of RP-ILD associated with JDM.

METHODS

The clinical records of 54 patients with JDM were retrospectively reviewed: 10 had RP-ILD (7 died, 3 survived), 19 had chronic ILD and 24 were without ILD. Routine tests included a high-resolution CT (HRCT) scan of the chest and measurement of serum levels of creatine phosphokinase, ferritin and Krebs von den Lungen-6 (KL-6). Anti-melanoma differentiation-associated gene 5 (MDA5) antibodies and IL-18 levels were measured by ELISA.

RESULTS

No differences were found in the ratio of juvenile clinically amyopathic DM between the three groups. Initial chest HRCT scan findings were variable and could not distinguish between RP-ILD and chronic ILD. Anti-MDA5 antibodies were positive in all 8 patients with RP-ILD and 10 of 14 with chronic ILD, but none of the patients without ILD. Serum levels of anti-MDA5 antibody, ferritin, KL-6 and IL-18 were significantly higher in the RP-ILD group than in the chronic ILD and non-ILD groups. Serum levels of IL-18 positively correlated with serum KL-6 (R = 0.66, P < 0.001).

CONCLUSION

High serum levels of IL-18, KL-6, ferritin and anti-MDA5 antibodies (e.g. >200 units by ELISA) are associated with RP-ILD. These can be used as an indication for early intensive treatment. Both alveolar macrophages and autoimmunity to MDA5 are possibly involved in the development of RP-ILD associated with JDM.

Molecular biomarkers in idiopathic pulmonary fibrosis

Molecular biomarkers are highly desired in idiopathic pulmonary fibrosis (IPF), where they hold the potential to elucidate underlying disease mechanisms, accelerated drug development, and advance clinical management. Currently, there are no molecular biomarkers in widespread clinical use for IPF, and the search for potential markers remains in its infancy. Proposed core mechanisms in the pathogenesis of IPF for which candidate markers have been offered include alveolar epithelial cell dysfunction, immune dysregulation, and fibrogenesis. Useful markers reflect important pathological pathways, are practically and accurately measured, have undergone extensive validation, and are an improvement upon the current approach for their intended use. The successful development of useful molecular biomarkers is a central challenge for the future of translational research in IPF and will require collaborative efforts among those parties invested in advancing the care of patients with IPF.

Seasonal variation of serum KL-6 concentrations is greater in patients with hypersensitivity pneumonitis

BACKGROUND

Serum KL-6 is a useful biomarker for the diagnosis of interstitial lung diseases (ILD). However, KL-6 has not been used to discriminate different types of ILD. Serum KL-6 concentrations can vary depending on antigen exposure levels in patients with hypersensitivity pneumonitis (HP); however, seasonal changes in serum KL-6 concentrations in ILD have not been determined. We hypothesized that seasonal variation of serum KL-6 is greater in HP than for the other ILD. The aim of this study was to determine seasonal variation of serum KL-6 concentrations in various ILD.

METHODS

Serum KL-6 concentrations in the summer season from June 1 to September 30 and the winter season from November 1 to February 28 were retrospectively analyzed in patients with idiopathic pulmonary fibrosis (IPF, n=16), non-specific interstitial pneumonia (NSIP, n=16), collagen vascular disease-associated interstitial pneumonia (CVD-IP, n=33), house-related HP (House-HP, n=9), bird-related HP (Bird-HP, n=9), and combined pulmonary fibrosis and emphysema (CPFE, n=13).

RESULTS

Bird-HP and House-HP showed greater seasonal serum KL-6 variation than the other ILD. Serum KL-6 concentrations in Bird-HP were significantly increased in the winter and KL-6 concentrations in House-HP were significantly increased in the summer. Serum KL-6 variation was significantly greater in acute HP than chronic HP. Receiver operating characteristic curve analysis revealed that greater seasonal variation in serum KL-6 concentrations is diagnostic for Bird-HP.

CONCLUSION

HP should be considered in ILD with greater seasonal changes in serum KL-6 concentrations.

An intractable case of Hermansky-Pudlak syndrome

A 52-year-old Japanese man with congenital amblyopia and oculocutaneous albinism was admitted to our hospital. Chest CT showed reticular opacities and traction bronchiectasis without honeycombing. Specimens obtained by a video-assisted thoracoscopic surgery showed patchy chronic fibrotic lesions. We diagnosed him with Hermansky-Pudlak syndrome (HPS). A mutation in the HPS1 gene was detected, and the diagnosis was confirmed. The patient was treated with prednisolone, pirfenidone, and azathioprine, but he nevertheless died within four months. Autopsy lung specimens showed diffuse alveolar damage suggesting comparatively rapid deterioration, although this presentation was not typical of an acute exacerbation. These pathological changes may be a possible progression pattern in HPS patients.

Idiopathic pulmonary fibrosis: from epithelial injury to biomarkers--insights from the bench side

Idiopathic pulmonary fibrosis (IPF) is the most frequent fibrotic diffuse parenchymal lung disease. Its prognosis is devastating: >50% of the patients die within 3 years after diagnosis. Options for the treatment of IPF are limited and lung transplantation is the only 'curative' therapy. Currently, in the absence of validated indicators of disease progression/activity and diagnostic tools, the clinical management of IPF remains a major challenge. A better understanding of the pathogenesis of IPF is critical for the identification of new therapeutic targets as well as molecules that may serve as surrogate markers for clinically significant endpoints. The current paradigm on the mechanisms leading from a normal to a fibrotic lung postulates that chronic epithelial lesion leads to aberrant wound healing activation, which is characterized by deregulated fibroblast proliferation and activation together with an uncontrolled extracellular matrix synthesis. In this review, we shed light on the role of epithelial cell damage in the pathogenesis of fibrosis. Finally, we examine the markers of epithelial damage and their potential use as biomarkers and the future of this continuously expanding field.

Tanshinone IIA inhibits lipopolysaccharide-induced MUC1 overexpression in alveolar epithelial cells

The anti-inflammatory function of tanshinone IIA (TIIA), an active natural compound from Chinese herbal medicine Danshen, has been well recognized, and therefore TIIA has been widely used to treat various inflammatory conditions associated with cardiac and lung diseases. Mucin 1 (Muc1) plays important anti-inflammatory roles in resolution of acute lung inflammation. In this study, we investigated the effects of TIIA on LPS-induced acute lung inflammation, as well as its relationship to Muc1 expression in mouse lung and MUC1 in human alveolar epithelial cells. TIIA pretreatment significantly inhibited LPS-induced pulmonary inflammation in both Muc1 wild-type (Muc1(+/+)) and knockout (Muc1(-/-)) mice, as manifested by reduced neutrophil infiltration and reduced TNF-α and keratinocyte chemoattractant levels in bronchoalveolar lavage fluid. The inhibitory effects of TIIA on airway inflammation were associated with reduced expression of Muc1 in Muc1(+/+) mouse lung. Moreover, pretreatment with TIIA significantly inhibited LPS-induced MUC1 expression and TNF-α release in A549 alveolar epithelial cells. TNF-α upregulated MUC1 mRNA and protein expression in A549 cells, which was inhibited by pretreatment with TIIA. The LPS-induced MUC1 expression was blocked when A549 cells were transfected with siRNA targeting for TNF-α receptor 1. Furthermore, TIIA inhibited LPS-induced nuclear translocation of NF-κB and upregulation of Toll-like receptor 4 in A549 cells. Taken together, these results demonstrate that TIIA suppressed LPS-induced acute lung inflammation regardless of the presence of Muc1, and TIIA inhibited LPS- and TNF-α-induced MUC1/Muc1 expression in airway epithelial cells, suggesting that MUC1/Muc1 does not account for the mechanisms of the anti-inflammatory effects of TIIA in the airway.

Pathogenesis of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fibrosing interstitial lung disease associated with aging that is characterized by the histopathological pattern of usual interstitial pneumonia. Although an understanding of the pathogenesis of IPF is incomplete, recent advances delineating specific clinical and pathologic features of IPF have led to better definition of the molecular pathways that are pathologically activated in the disease. In this review we highlight several of these advances, with a focus on genetic predisposition to IPF and how genetic changes, which occur primarily in epithelial cells, lead to activation of profibrotic pathways in epithelial cells. We then discuss the pathologic changes within IPF fibroblasts and the extracellular matrix, and we conclude with a summary of how these profibrotic pathways may be interrelated.

Acute Exacerbation of Idiopathic Pulmonary Fibrosis

Acute exacerbation of idiopathic pulmonary fibrosis (IPF) is a clinically important complication of IPF that carries a high morbidity and mortality. In the last decade, we have learned much about this event, but there are many remaining questions: What is it? Why does it happen? How can we prevent it? How can we treat it? This chapter attempts to summarize our current understanding of the epidemiology, etiology, and management of acute exacerbation of IPF and point out areas where additional data are sorely needed.

Blood biomarkers MMP-7 and SP-A: predictors of outcome in idiopathic pulmonary fibrosis

BACKGROUND

Because of the variable course of idiopathic pulmonary fibrosis (IPF), it is important to generate an accurate prognosis at the time of diagnosis. The aim of this study was to investigate the prognostic value of blood biomarkers in IPF.

METHODS

The plasma level of the biomarkers, matrix metalloproteinase-7 (MMP-7), Krebs von den Lungen-6 antigen, and surfactant protein (SP)-A and SP-D were retrospectively compared with the clinical course of 118 patients with IPF, 68 of whom had biopsy-proven IPF.

RESULTS

The median follow-up period was 24 months. Multivariate Cox analysis showed MMP-7 (HR, 1.056; P = .0063) and SP-A (HR, 1.011; P = .0001) were significant predictors of survival along with age, FVC, and extent of honeycombing. The patients with high levels of both MMP-7 (≥ 12.1 ng/mL) and SP-A (≥ 80.3 ng/mL) had shorter survival (1-year survival rate: 59%) and higher frequency (42%) of lung function decline (&gt; 10% reduction in FVC in 6 months) compared with those with high levels of one biomarker (1-year survival rate: 81%; FVC decline: 27%) or low levels of both (1-year survival rate: 83.3%; FVC decline: 9%). Multivariate models demonstrated marginal improvement in the prediction of mortality (concordance index [C-index]: 0.731; P = .061) when MMP-7 and SP-A were included and compared with standard clinical predictors only (C-index: 0.686); however, it became significant with addition of MMP-7, SP-A, and Krebs von den Lungen-6 antigen (C-index: 0.730; P = .037).

CONCLUSIONS

Our retrospective study suggested that at least three biomarkers are necessary to improve predictability of mortality in IPF compared with clinical parameters. Further study in a greater number of patients is warranted.

Approach to acute exacerbation of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial pneumonia with a median survival of 3 years after diagnosis. Acute exacerbation of IPF (AE-IPF) is now identified as a life-threatening complication. It presents as worsening dyspnea with new ground glass opacities superimposed upon a radiographic usual interstitial pneumonia (UIP) pattern. It is a diagnosis of exclusion. The prognosis of AE-IPF is poor and treatment strategies lack standardization. In order to rule out any reversible etiology for an acute decompensation of a previously stable IPF patient diagnostic modalities include computerized tomographic angiogram (CTA) coupled with high-resolution computerized tomography (HRCT) imaging of the chest, bronchoalveolar lavage (BAL) and echocardiogram with bubble study. Avoiding risk factors, identifying underlying causes and supportive care are the mainstays of treatment. Anti-inflammatory and immunosuppressant medications have not shown to improve survival in AE-IPF. Most of the patients are managed in a critical care setting with mechanical ventilation. Lung transplantation is a promising option but most institutions are not equipped and not every patient is a candidate.

Serum KL-6 is a predictor of outcome in pulmonary alveolar proteinosis

Background

Pulmonary alveolar proteinosis (PAP) is a rare disorder characterised by abundant alveolar accumulation of surfactant lipoproteins. Serum levels of KL-6, high molecular weight human MUC1 mucin, are increased in the majority of patients with PAP. The prognostic significance of KL-6 in PAP is still unknown. Aim of the study was to evaluate whether serum KL-6 levels correlate with the outcome of the disease.

Patients and methods

From 2006 to 2012, we prospectively studied 33 patients with primary autoimmune PAP. We measured serum KL-6 levels by ELISA (Eisai, Tokyo, Japan), and evaluated the correlation between initial KL-6 levels and clinical variables. Disease progression was defined as deterioration of symptoms, and/or lung function, and/or chest imaging.

Main results

The initial serum KL-6 levels were significantly correlated with the baseline PaO₂, A-aDO₂, DLCO, VC and TLC (p=0.042, 0.012, 0.012, 0.02 and 0.013, respectively). The change over time of serum KL-6 correlated with the change over time of DLCO (p=0.017). The initial serum KL-6 levels were significantly higher in patients with disease progression than in those with remission (p<0.001). At a cut-off level of 1526 U/mL, the initial serum KL-6 level predicted disease progression (Se 81%, Sp 94%). At a cut-off level of 2157 U/mL, the initial serum KL-6 predicted the necessity of repeated whole lung lavage (Se 83%, Sp 96%). In the multivariate analysis, the initial serum level of KL-6 was the strongest predictor of disease progression (HR 9.41, p=0.008).

Conclusions

Serum KL-6 seems to predict outcome in PAP.

The diagnosis of idiopathic pulmonary fibrosis and its complications

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a devastating, progressive condition with a median survival of 2.8 - 4 years from diagnosis. Clinicians confronted with a patient with fibrosing lung disease need to be reliably able to distinguish IPF from other diffuse parenchymal lung diseases. Furthermore, they need to be able to gauge prognosis, evaluate timing of interventions including referral for transplant, assess reliably the effectiveness of treatment and be able to detect rapidly the development of disease complications.

OBJECTIVE/METHOD

This paper provides an overview of currently available diagnostic tests for IPF and its complications and evaluates the possible future role of candidate biomarkers in the diagnosis and assessment of patients with IPF. A literature search was performed for papers evaluating diagnostic tests in the diagnosis of IPF and its complications.

CONCLUSION

Computed tomography combined with clinical data is sufficient for diagnosing IPF in approximately two-thirds of patients with the condition. For the remaining patients, histological assessment is important in achieving a precise diagnosis. Serial measurements of carbon monoxide diffusing capacity and forced vital capacity provide the best prognostic indicator in IPF. Potential biomarkers for diagnosing IPF include KL-6, MMP1 and MMP7. Brain naturetic peptide shows promise as a non-invasive screening tool for the diagnosis of IPF-associated pulmonary hypertension.

KL-6, a Human MUC1 Mucin, as a prognostic marker for diffuse alveolar hemorrhage syndrome

Background

Diffuse alveolar hemorrhage syndrome is a life threatening condition with diverse etiologies. Sensitive prognostic markers for diffuse alveolar hemorrhage have not been well investigated. Serum KL-6 is a biomarker for various interstitial lung disease associated with disease activity and prognosis. The purpose of the present study was to evaluate the clinical utility of serum KL-6 level as a prognostic marker for diffuse alveolar hemorrhage.

Methods

We retrospectively collected 41 consecutive patients clinically diagnosed as having diffuse alveolar hemorrhage who were admitted to the Intensive Care Unit of Hiroshima University Hospital between 2004 and 2011. Correlation between prognosis and age, sex, laboratory findings including serum KL-6, radiological findings, ventilatory modes or therapeutic regimens were evaluated.

Results

Baseline and peak serum KL-6 levels were significantly higher in non-survivors compared with survivors. An increase in KL-6 levels during the initial week was associated with a subsequent deterioration of the oxygenation index. Higher baseline KL-6 levels and higher peak KL-6 levels were strongly correlated with death. With a cut-off level of 700 U/mL for peak KL-6, the sensitivity, specificity and accuracy for non-survival were 75%, 85% and 78%, respectively. In the multivariate analysis, only the peak KL-6 level ≥700 U/ml was an independent poor prognostic factor for diffuse alveolar hemorrhage.

Conclusions

Peak serum KL-6 level ≥700 U/ml may become a clinically useful marker of poor prognosis for diffuse alveolar hemorrhage.

Risk of Acute Exacerbation After Video-assisted Thoracoscopic Lung Biopsy for Interstitial Lung Disease

Biopsy by video-assisted thoracoscopic surgery (VATS) for interstitial pneumonia allows collection of samples sufficient for accurate histologic diagnosis. Although VATS is relatively safe, several reports have suggested that surgical lung biopsy may be a risk factor for acute exacerbation of idiopathic pulmonary fibrosis (IPF). We retrospectively reviewed data on the 113 cases that underwent biopsy by VATS to diagnose diffuse parenchymal lung disease in our department between 1994 and 2006, and analyzed its complications, in particular, risk of acute exacerbation of IPF. As the final diagnosis, idiopathic interstitial pneumonia was most frequent, involving 52 cases, of which IPF was most frequently found followed by nonspecific interstitial pneumonia and cryptogenic organizing pneumonia, in that order. Among our cases, there were 2 deaths after VATS (mortality rate, 1.8%), and both were IPF cases with acute exacerbation. When examining clinical markers in the 2 fatal IPF cases with acute exacerbation, we found that the percentage of predicted forced vital capacity was 55 or lower, percentage of predicted carbon monoxide diffusing capacity was 40 or lower, serum interstitial pneumonia markers KL-6 and SP-D were elevated, intraoperative inhalation of 100% O2 was 80 minutes or longer, and postoperative thoracic drainage was required for 10 days or longer. Although acute exacerbations of IPF seem to occur at any time during the course of disease, it is important to be aware of the possibility of acute exacerbation of IPF after VATS.

Cleaved cytokeratin-18 is a mechanistically informative biomarker in idiopathic pulmonary fibrosis

Background

Stress of the endoplasmic reticulum (ER) leading to activation of the unfolded protein response (UPR) and alveolar epithelial cell (AEC) apoptosis may play a role in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Our objectives were to determine whether circulating caspase-cleaved cytokeratin-18 (cCK-18) is a marker of AEC apoptosis in IPF, define the relationship of cCK-18 with activation of the UPR, and assess its utility as a diagnostic biomarker.

Methods

IPF and normal lung tissues were stained with the antibody (M30) that specifically binds cCK-18. The relationship between markers of the UPR and cCK-18 was determined in AECs exposed in vitro to thapsigargin to induce ER stress. cCK-18 was measured in serum from subjects with IPF, hypersensitivity pneumonitis (HP), nonspecific interstitial pneumonia (NSIP), and control subjects.

Results

cCK-18 immunoreactivity was present in AECs of IPF lung, but not in control subjects. Markers of the UPR (phosphorylated IRE-1α and spliced XBP-1) were more highly expressed in IPF type II AECs than in normal type II AECs. Phosphorylated IRE-1α and cCK-18 increased following thapsigargin-induced ER stress. Serum cCK-18 level distinguished IPF from diseased and control subjects. Serum cCK-18 was not associated with disease severity or outcome.

Conclusions

cCK-18 may be a marker of AEC apoptosis and UPR activation in patients with IPF. Circulating levels of cCK-18 are increased in patients with IPF and cCK-18 may be a useful diagnostic biomarker.

Serological investigation of the collagen degradation profile of patients with chronic obstructive pulmonary disease or idiopathic pulmonary fibrosis

In both chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), abnormally high collagen remodeling occurs within the lung tissue. Matrix metalloproteinase (MMP)-degraded type I, III, IV, V and VI collagen and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-degraded type III collagen were assessed in serum of patients diagnosed with mild COPD (n = 10) or IPF (n = 30), and healthy controls (n = 15). The collagen degradation markers C1M, C3M, C5M and C6M were significantly elevated in serum of both mild COPD and IPF patients, versus controls. C3A and C4M were only elevated in patients with mild COPD, compared with controls. The most reliable indicators of mild COPD versus controls were: C1M (area under the receiver-operating characteristics (AUROC = 0.94, P < 0.0001), C3M (AUROC = 0.95, P < 0.0001), and C5M (AUROC = 0.95, P < 0.0001). The most reliable markers for the diagnosis of IPF were achieved by C1M (AUROC = 0.90, P < 0.0001) and C3M (AUROC = 0.93, P < 0.0001). Collagen degradation was highly up-regulated in patients with IPF and mild COPD, indicating that degradation fragments of collagens are potential markers of pulmonary diseases. Interestingly, C4M and C3A were only elevated in patients with mild COPD, indicating that these markers could be used to distinguish between the two pathologies.

Correlation between circulating fibrocytes, and activity and progression of interstitial lung diseases

BACKGROUND AND OBJECTIVE

Interstitial lung diseases (ILD) are characterized by progressive interstitial pulmonary fibrosis and a decline in lung function. Fibrocytes are bone marrow-derived mesenchymal progenitor cells that may play a role in the pathogenesis of pulmonary fibrosis. Circulating fibrocyte numbers have been correlated with the prognosis of patients with idiopathic pulmonary fibrosis. The aim of the present study was to evaluate the relationship between circulating fibrocytes, and parameters of disease activity and progression in several groups of patients with ILD.

METHODS

The study population comprised 41 patients with ILD and seven healthy control subjects. Circulating CD45(+) collagen-I(+) fibrocytes were evaluated by flow cytometry.

RESULTS

The number of circulating fibrocytes was significantly increased in all patients with ILD and particularly in patients with idiopathic interstitial pneumonitis and interstitial pneumonitis associated with collagen vascular disease as compared with healthy control subjects. The numbers of circulating fibrocytes were significantly correlated with pulmonary function test parameters and with serum levels of sialylated carbohydrate antigen, a marker of disease activity. Temporal changes in circulating fibrocyte numbers were evaluated in two patients, and the results suggested that these changes correlated with the activity of ILD.

CONCLUSIONS

The results from this study provide further evidence for the role of circulating fibrocytes in fibrotic lung diseases.

Efficacy of inhaled N-acetylcysteine monotherapy in patients with early stage idiopathic pulmonary fibrosis

BACKGROUND AND OBJECTIVE

Idiopathic pulmonary fibrosis (IPF) is a fatal disorder for which there are currently no specific or effective medical treatments. A multicentre, prospective, randomized, controlled clinical trial was conducted to assess the efficacy of inhaled N-acetylcysteine (NAC) monotherapy in Japanese patients with early stage IPF.

METHODS

Eligible patients had well-defined IPF of mild-to-moderate severity, with no desaturation on exercise. Of 100 patients screened, 76 were randomly assigned to an NAC treatment group (group A; n = 38) that received 352.4 mg of NAC by inhalation twice daily or to a control group (group B; n = 38) that received no therapy. The primary endpoint was the change from baseline in forced vital capacity (FVC) at 48 weeks.

RESULTS

There were no significant overall differences in the change in FVC between groups A and B. Post hoc exploratory analyses showed that NAC therapy was associated with stability of FVC in (i) a subset of patients with initial FVC <95% of predicted (n = 49; difference in FVC decline 0.12 L; P = 0.02) and (ii) in patients with initial diffusing capacity of carbon monoxide <55% of predicted (n = 21; difference in FVC decline 0.17 L; P = 0.009).

CONCLUSIONS

These findings indicate that NAC monotherapy may have some beneficial effect in patients with early stage IPF. Further trials in more select IPF populations with progressive disease are required to prove the efficacy of inhaled NAC.

Peripheral blood biomarkers in idiopathic pulmonary fibrosis

In this article, we review the evidence for peripheral blood biomarkers in idiopathic pulmonary fibrosis (IPF), a life-threatening fibrotic lung disease of unknown etiology. We focus on selected biomarkers present in peripheral blood, as they are easy to obtain, can be measured longitudinally, and have the greatest likelihood of achieving clinical utility. This article concentrates on biomarkers with mechanistic plausibility that may be directly involved in the development of IPF, including KL-6, surfactant proteins A and D, matrix metalloproteases (MMP) 1 and 7, CCL18, VEGF, YKL-40, osteopontin, circulating fibrocytes, and T cells. After reviewing the evidence base for each, we designate the biomarkers that may have utility as: (1) diagnostic biomarkers to distinguish IPF from other interstitial lung diseases, (2) prognostic biomarkers that are correlated with disease progression or mortality, or (3) biomarkers that can be used as tools for serial monitoring of disease severity. Although there are no validated biomarkers that are currently available, the need for surrogates of diagnosis, prognosis, and monitoring of disease course with emerging therapies is great.

Utility of KL-6/MUC1 in the clinical management of interstitial lung diseases

Interstitial lung diseases (ILDs) are a diverse group of pulmonary disorders characterized by various patterns of inflammation and fibrosis in the interstitium of the lung. Because injury and/or regeneration of type II pneumocytes are prominent histological features of ILDs, substances derived from type II pneumocytes have been the focus of research investigating potential biomarkers for ILD. One important biomarker for ILD is the high-molecular-weight glycoprotein, Krebs von den Lungen-6 (KL-6). KL-6 is now classified as a human MUC1 mucin protein, and regenerating type II pneumocytes are the primary cellular source of KL-6/MUC1 in the affected lungs of patients with ILD. KL-6/MUC1 is detectable in the serum of patients with ILD, and extensive investigations performed primarily in Japan have revealed that serum KL-6/MUC1 is elevated in 70-100% of patients with various ILDs, including idiopathic interstitial pneumonias, collagen vascular disease-associated interstitial pneumonia, hypersensitivity pneumonia, radiation pneumonitis, drug-induced ILDs, acute respiratory distress syndrome, pulmonary sarcoidosis, and pulmonary alveolar proteinosis. The results from these various studies have supported the utility of KL-6/MUC1 as a serum biomarker for detecting these various ILDs. Moreover, KL-6/MUC1 serum levels have been demonstrated to be useful for evaluating disease activity and predicting the clinical outcomes of various ILD types. Based on these observations, we believe that KL-6/MUC1 is currently one of the best and most reliable serum biomarkers available for ILD management.

Change in serum KL-6 level from baseline is useful for predicting life-threatening EGFR-TKIs induced interstitial lung disease

Background

A high incidence of interstitial lung disease (ILD) has been reported in patients with advanced non-small cell lung cancer (NSCLC) treated with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), particularly in Japanese populations. A previous report from our laboratory demonstrated that KL-6 was a useful serum biomarker to assess the severity of drug-induced pneumonitis. Based on these observations, this study was conducted to evaluate the risk factors of EGFR-TKIs induced ILD and the usefulness of monitoring serum KL-6 levels in patients who developed EGFR-TKIs induced ILD in a large multi-institutional setting.

Methods

We retrospectively reviewed clinical records and radiographies of 341 patients with advanced NSCLCs who were treated with EGFR-TKIs, and analyzed risk factors for the development of EGFR-TKIs induced ILD. Changes of circulating levels of KL-6 were also evaluated in the patients who developed EGFR-TKIs induced ILD.

Results

Among the 341 patients included in this study, 20 (5.9%) developed EGFR-TKIs induced ILD, and 9 (2.6%) died from ILD. Univariate analyses revealed that only preexisting pulmonary fibrosis was a significant risk factor for the development of EGFR-TKIs induced ILD (p = 0.003). Absolute levels of circulating KL-6 at neither baseline nor the onset of ILD could discriminate between life-threatening and non-life threatening EGFR-TKIs induced ILDs. However, we found that the ratios of serum KL-6 levels just after the onset of EGFR-TKIs induced ILD to those at baseline could quite precisely distinguish survivors from non-survivors (p = 0.006) as well as acute interstitial pneumonia (AIP) pattern from non-AIP pattern (p = 0.005).

Conclusions

The results of this study strongly support the potential of KL-6 as a diagnostic biomarker for life-threatening EGFR-TKIs induced ILD. Monitoring of KL-6 is also useful to evaluate the progression and severity of EGFR-TKIs induced ILD.

A micro RNA processing defect in rapidly progressing idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis exhibits differential progression from the time of diagnosis but the molecular basis for varying progression rates is poorly understood. The aim of the present study was to ascertain whether differential miRNA expression might provide one explanation for rapidly versus slowly progressing forms of IPF.

Methodology and Principal Findings

miRNA and mRNA were isolated from surgical lung biopsies from IPF patients with a clinically documented rapid or slow course of disease over the first year after diagnosis. A quantitative PCR miRNA array containing 88 of the most abundant miRNA in the human genome was used to profile lung biopsies from 9 patients with rapidly progressing IPF, 6 patients with slowly progressing IPF, and 10 normal lung biopsies. Using this approach, 11 miRNA were significantly increased and 36 were significantly decreased in rapid biopsies compared with normal biopsies. Slowly progressive biopsies exhibited 4 significantly increased miRNA and 36 significantly decreased miRNA compared with normal lung. Among the miRNA present in IPF with validated mRNA targets were those with regulatory effects on epithelial-mesenchymal transition (EMT). Five miRNA (miR-302c, miR-423-5p, miR-210, miR-376c, and miR-185) were significantly increased in rapid compared with slow IPF lung biopsies. Additional analyses of rapid biopsies and fibroblasts grown from the same biopsies revealed that the expression of AGO1 and AGO2 (essential components of the miRNA processing RISC complex) were lower compared with either slow or normal lung biopsies and fibroblasts.

Conclusion

These findings suggest that the development and/or clinical progression of IPF might be the consequence of aberrant miRNA processing.