High plasma concentrations of osteopontin in patients with interstitial pneumonia

The critical role of osteopontin (OPN) in fibrotic diseases

Fibrosis is a pathological condition characterized by the excessive deposition of extracellular matrix components in tissues and organs, leading to progressive architectural remodelling and contributing to the development of various diseases. Osteopontin (OPN), a highly phosphorylated glycoprotein, has been increasingly recognized for its involvement in the progression of tissue fibrosis. This review provides a comprehensive overview of the genetic and protein structure of OPN and focuses on our current understanding of the role of OPN in the development of fibrosis in the lungs and other tissues. Additionally, special attention is given to the potential of OPN as a biomarker and a novel therapeutic target in the treatment of fibrosis.

Molecular Mechanisms and Cellular Contribution from Lung Fibrosis to Lung Cancer Development

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrosing interstitial lung disease (ILD) of unknown aetiology, with a median survival of 2-4 years from the time of diagnosis. Although IPF has unknown aetiology by definition, there have been identified several risks factors increasing the probability of the onset and progression of the disease in IPF patients such as cigarette smoking and environmental risk factors associated with domestic and occupational exposure. Among them, cigarette smoking together with concomitant emphysema might predispose IPF patients to lung cancer (LC), mostly to non-small cell lung cancer (NSCLC), increasing the risk of lung cancer development. To this purpose, IPF and LC share several cellular and molecular processes driving the progression of both pathologies such as fibroblast transition proliferation and activation, endoplasmic reticulum stress, oxidative stress, and many genetic and epigenetic markers that predispose IPF patients to LC development. Nintedanib, a tyrosine-kinase inhibitor, was firstly developed as an anticancer drug and then recognized as an anti-fibrotic agent based on the common target molecular pathway. In this review our aim is to describe the updated studies on common cellular and molecular mechanisms between IPF and lung cancer, knowledge of which might help to find novel therapeutic targets for this disease combination.

Circulating Osteopontin Levels and Outcomes in Patients Hospitalized for COVID-19

BACKGROUND

Severe coronavirus disease 2019 (COVID-19) is the result of a hyper-inflammatory reaction to the severe acute respiratory syndrome coronavirus 2. The biomarkers of inflammation have been used to risk-stratify patients with COVID-19. Osteopontin (OPN) is an integrin-binding glyco-phosphoprotein involved in the modulation of leukocyte activation; its levels are associated with worse outcomes in patients with sepsis. Whether OPN levels predict outcomes in COVID-19 is unknown.

METHODS

We measured OPN levels in serum of 341 hospitalized COVID-19 patients collected within 48 h from admission. We characterized the determinants of OPN levels and examined their association with in-hospital outcomes; notably death, need for mechanical ventilation, and need for renal replacement therapy (RRT) and as a composite outcome. The risk discrimination ability of OPN was compared with other inflammatory biomarkers.

RESULTS

Patients with COVID-19 (mean age 60, 61.9% male, 27.0% blacks) had significantly higher levels of serum OPN compared to healthy volunteers (96.63 vs. 16.56 ng/mL, p < 0.001). Overall, 104 patients required mechanical ventilation, 35 needed dialysis, and 53 died during their hospitalization. In multivariable analyses, OPN levels ≥140.66 ng/mL (third tertile) were associated with a 3.5 × (95%CI 1.44-8.27) increase in the odds of death, and 4.9 × (95%CI 2.48-9.80) increase in the odds of requiring mechanical ventilation. There was no association between OPN and need for RRT. Finally, OPN levels in the upper tertile turned out as an independent prognostic factor of event-free survival with respect to the composite endpoint.

CONCLUSION

Higher OPN levels are associated with increased odds of death and mechanical ventilation in patients with COVID-19, however, their utility in triage is questionable.

Molecular Biomarkers in Idiopathic Pulmonary Fibrosis: State of the Art and Future Directions

Idiopathic pulmonary fibrosis (IPF), the most lethal form of interstitial pneumonia of unknown cause, is associated with a specific radiological and histopathological pattern (the so-called "usual interstitial pneumonia" pattern) and has a median survival estimated to be between 3 and 5 years after diagnosis. However, evidence shows that IPF has different clinical phenotypes, which are characterized by a variable disease course over time. At present, the natural history of IPF is unpredictable for individual patients, although some genetic factors and circulating biomarkers have been associated with different prognoses. Since in its early stages, IPF may be asymptomatic, leading to a delayed diagnosis. Two drugs, pirfenidone and nintedanib, have been shown to modify the disease course by slowing down the decline in lung function. It is also known that 5-10% of the IPF patients may be affected by episodes of acute and often fatal decline. The acute worsening of disease is sometimes attributed to identifiable conditions, such as pneumonia or heart failure; but many of these events occur without an identifiable cause. These idiopathic acute worsenings are termed acute exacerbations of IPF. To date, clinical biomarkers, diagnostic, prognostic, and theranostic, are not well characterized. However, they could become useful tools helping facilitate diagnoses, monitoring disease progression and treatment efficacy. The aim of this review is to cover molecular mechanisms underlying IPF and research into new clinical biomarkers, to be utilized in diagnosis and prognosis, even in patients treated with antifibrotic drugs.

Orotracheal treprostinil administration attenuates bleomycin-induced lung injury, vascular remodeling, and fibrosis in mice

Pulmonary fibrosis is a progressive disease characterized by disruption of lung architecture and deregulation of the pulmonary function. Prostacyclin, a metabolite of arachidonic acid, is a potential disease mediator since it exerts anti-inflammatory and anti-fibrotic actions. We investigated the effect of treprostinil, a prostacyclin analogue, in bleomycin-induced experimental pulmonary fibrosis. Bleomycin sulfate or saline was administrated intratracheally to mice (n = 9-10/group) at day 0. Orotracheal aspiration of treprostinil or vehicle was administered daily and started 24 h prior to bleomycin challenge. Evaluation of lung pathology was performed in tissue samples and bronchoalveolar lavage fluid collected 7, 14 and 21 days after bleomycin exposure. Lung injury was achieved due to bleomycin exposure at all time points as indicated by impaired lung mechanics, pathologic lung architecture (from day 14), and cellular and protein accumulation in the alveolar space accompanied by a minor decrease in lung tissue VE-cadherin at day 14. Treprostinil preserved lung mechanics, and reduced lung inflammation, fibrosis, and vascular remodeling (day 21); reduced cellularity and protein content of bronchoalveolar lavage fluid were additionally observed with no significant effect on VE-cadherin expression. Bleomycin-induced collagen deposition was attenuated by treprostinil from day 14, while treprostinil involvement in regulating inflammatory processes appears mediated by NF-κB signaling. Overall, prophylactic administration of treprostinil, a stable prostacyclin analogue, maintained lung function, and prevented bleomycin-induced lung injury, and fibrosis, as well as vascular remodeling, a hallmark of pulmonary hypertension. This suggests potential therapeutic efficacy of treprostinil in pulmonary fibrosis and possibly in pulmonary hypertension related to chronic lung diseases.

The therapy of idiopathic pulmonary fibrosis: what is next?

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrosing interstitial lung disease, characterised by progressive scarring of the lung and associated with a high burden of disease and early death. The pathophysiological understanding, clinical diagnostics and therapy of IPF have significantly evolved in recent years. While the recent introduction of the two antifibrotic drugs pirfenidone and nintedanib led to a significant reduction in lung function decline, there is still no cure for IPF; thus, new therapeutic approaches are needed. Currently, several clinical phase I-III trials are focusing on novel therapeutic targets. Furthermore, new approaches in nonpharmacological treatments in palliative care, pulmonary rehabilitation, lung transplantation, management of comorbidities and acute exacerbations aim to improve symptom control and quality of life. Here we summarise new therapeutic attempts and potential future approaches to treat this devastating disease.

Current Status and Future Opportunities in Lung Precision Medicine Research with a Focus on Biomarkers. An American Thoracic Society/National Heart, Lung, and Blood Institute Research Statement

BACKGROUND

Thousands of biomarker tests are either available or under development for lung diseases. In many cases, adoption of these tests into clinical practice is outpacing the generation and evaluation of sufficient data to determine clinical utility and ability to improve health outcomes. There is a need for a systematically organized report that provides guidance on how to understand and evaluate use of biomarker tests for lung diseases.

METHODS

We assembled a diverse group of clinicians and researchers from the American Thoracic Society and leaders from the National Heart, Lung, and Blood Institute with expertise in various aspects of precision medicine to review the current status of biomarker tests in lung diseases. Experts summarized existing biomarker tests that are available for lung cancer, pulmonary arterial hypertension, idiopathic pulmonary fibrosis, asthma, chronic obstructive pulmonary disease, sepsis, acute respiratory distress syndrome, cystic fibrosis, and other rare lung diseases. The group identified knowledge gaps that future research studies can address to efficiently translate biomarker tests into clinical practice, assess their cost-effectiveness, and ensure they apply to diverse, real-life populations.

RESULTS

We found that the status of biomarker tests in lung diseases is highly variable depending on the disease. Nevertheless, biomarker tests in lung diseases show great promise in improving clinical care. To efficiently translate biomarkers into tests used widely in clinical practice, researchers need to address specific clinical unmet needs, secure support for biomarker discovery efforts, conduct analytical and clinical validation studies, ensure tests have clinical utility, and facilitate appropriate adoption into routine clinical practice.

CONCLUSIONS

Although progress has been made toward implementation of precision medicine for lung diseases in clinical practice in certain settings, additional studies focused on addressing specific unmet clinical needs are required to evaluate the clinical utility of biomarkers; ensure their generalizability to diverse, real-life populations; and determine their cost-effectiveness.

Osteopontin Expression in Cardiomyocytes Is Increased in Pediatric Patients With Sepsis or Pneumonia

Sepsis and pneumonia are major causes of death in the United States, and their pathophysiology includes infection with inflammation and immune dysfunction. Both sepsis and pneumonia cause cardiovascular dysfunction. The expression of Osteopontin (OPN) in cardiomyocytes of patients with sepsis or pneumonia, and its role the induced cardiac dysfunction have not been thoroughly investigated. OPN is a matricellular protein synthesized by multiple diseased tissues and cells including cardiomyocytes. Here, we studied the expression of OPN protein using immunofluorescence in human myocardial autopsy tissues from pediatric and mid age or elderly patients with sepsis and/or pneumonia. Fourteen human myocardial tissues from six pediatric patients and eight mid-age or elderly patients were studied. Immunofluorescence was used to investigate the expression of OPN in paraffin-embedded heart sections co-stained with the myocyte markers Actin Alpha 1 (ACTA1) and Myosin Light Chain 2 (MLC2). A quantitative analysis was performed to determine the number of ACTA1 and MLC2 positive cardiomyocytes that express OPN. The results showed that OPN expression was significantly increased in cardiomyocytes in the hearts from pediatric patients with sepsis and/or pneumonia (N = 3) relative to pediatric patients without sepsis/pneumonia (N = 3), or adult to elderly patients with sepsis/pneumonia (N = 5). Among the older septic hearts, higher levels of cardiomyocyte OPN expression was seen only in conjunction with severe coronary arterial occlusion. This is the first study to document increased OPN expression in cardiomyocytes of pediatric subjects with sepsis or pneumonia. Our findings highlight a potentially important role for OPN in sepsis- or pneumonia-mediated cardiac dysfunction in pediatric patients.

Upregulation of osteopontin expression via the interaction of macrophages and fibroblasts under IL-1b stimulation

BACKGROUND

Fibrosis is attributed to dysregulation of tissue-remodeling. In remodeling areas, fibroblasts and macrophages actively make contact with each other. Osteopontin (OPN) is a pro-fibrotic molecule, whose expression is upregulated by interleukin (IL)-1β via secretion of its downstream cytokines, such as IL-6. Here, we investigated the effect of interaction between fibroblasts and macrophages under IL-1β stimulation on the expression of OPN.

METHODS

We used human lung fibroblasts and THP-1 macrophages differentiated from THP-1 cells using phorbol 12-myristate 13-acetate. These cells were either cultured alone or co-cultured under IL-1β stimulation. Secretion of OPN and IL-6 were examined by enzyme-linked immunosorbent assay, and mRNA expression was assessed by quantitative real-time PCR. The effects of siRNA against IL-6 or OPN on OPN expression were evaluated.

RESULTS

OPN expression increased when fibroblasts and THP-1 macrophages were co-cultured under IL-1β stimulation. The siRNA against IL-6 in fibroblasts suppressed the upregulation of OPN expression during co-culture, whereas siRNA against IL-6 in THP-1 macrophages did not. The upregulation of expression of OPN mRNA in fibroblasts or THP-1 macrophages when co-cultured under IL-1β stimulation was mediated by IL-6 from fibroblasts. OPN from THP-1 macrophages was involved in the increase of OPN expression in fibroblasts.

CONCLUSIONS

The present study revealed the crosstalk between fibroblasts and THP-1 macrophages under IL-1β stimulation, where IL-6 from fibroblasts, stimulated by IL-1β, upregulated OPN expression in fibroblasts themselves via increase in OPN from THP-1 macrophages. The fibroblasts/macrophages network may induce activation or qualitative changes in both cells, which contributes to inflammation-associated fibrosis.

Increased Levels of Free Circulating Dna in Patients with Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is difficult to diagnose because of numerous interstitial lung diseases with similar symptoms. As serum DNA has proven useful for early lung cancer detection, we aimed to define the relevance of this marker in discriminating IPF from other fibrotic and nonfibrotic/nonmalignant lung diseases. DNA was quantified in 191 subjects: 64 healthy individuals, 58 patients with IPF, 17 patients with nonspecific pulmonary fibrosis (13 idiopathic nonspecific interstitial pneumonia, 4 chronic hypersensitivity pneumonitis), and 52 patients with other diffuse/nonmalignant lung diseases. The median value of free DNA in IPF patients was 61.1 ng/mL (range 7.1–405), which was significantly higher than that of healthy donors (median 6.8, range 2.2–184) (p<0.001) and that of patients with other diffuse/nonmalignant lung diseases (median 28.0, range 4.2–281) (p=0.004). The area under the ROC curve was 0.926 (95% CI 0.879–0.973) when IPF patients were compared with healthy donors, and 0.702 (95% CI 0.609–0.796) when a comparison was made with non-IPF pulmonary diseases. In conclusion, we observed significantly higher levels of free circulating DNA in patients with IPF than in those with other fibrotic or diffuse/nonmalignant lung diseases.

Biomarkers in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, debilitating, fibrotic lung disease leading to respiratory failure and ultimately to death. Being the prototype of interstitial lung diseases, IPF is characterized by marked heterogeneity regarding its clinical course. Despite significant progress in the understanding of its pathogenesis, we still cannot reliably predict the course of the disease and the response to treatment of an individual patient. Non-invasive biomarkers, in particular serum biomarkers, for the (early) diagnosis, differential diagnosis, prognosis and prediction of therapeutic response are urgently needed. Numerous molecules involved in alveolar epithelial cell injury, fibroproliferation and matrix remodeling as well as immune regulation have been proposed as potential biomarkers. Furthermore, genetic variants of TOLLIP, MUC5B, and other genes are associated with a differential response to treatment and with the development and/or the prognosis of IPF. Additionally, the bacterial signature in IPF lungs, as shown from microbiome analyses, as well as mitochondrial DNA seem to have promising roles as biomarkers. Moreover, combination of multiple biomarkers may identify comprehensive biomarker signatures in IPF patients. However, there is still a long way until these potential biomarkers complete or substitute for the clinical and functional parameters currently available for IPF.

Idiopathic Pulmonary Fibrosis: A Genetic Disease That Involves Mucociliary Dysfunction of the Peripheral Airways

Idiopathic pulmonary fibrosis (IPF) is an incurable complex genetic disorder that is associated with sequence changes in 7 genes (MUC5B, TERT, TERC, RTEL1, PARN, SFTPC, and SFTPA2) and with variants in at least 11 novel loci. We have previously found that 1) a common gain-of-function promoter variant in MUC5B rs35705950 is the strongest risk factor (genetic and otherwise), accounting for 30-35% of the risk of developing IPF, a disease that was previously considered idiopathic; 2) the MUC5B promoter variant can potentially be used to identify individuals with preclinical pulmonary fibrosis and is predictive of radiologic progression of preclinical pulmonary fibrosis; and 3) MUC5B may be involved in the pathogenesis of pulmonary fibrosis with MUC5B message and protein expressed in bronchiolo-alveolar epithelia of IPF and the characteristic IPF honeycomb cysts. Based on these considerations, we hypothesize that excessive production of MUC5B either enhances injury due to reduced mucociliary clearance or impedes repair consequent to disruption of normal regenerative mechanisms in the distal lung. In aggregate, these novel considerations should have broad impact, resulting in specific etiologic targets, early detection of disease, and novel biologic pathways for use in the design of future intervention, prevention, and mechanistic studies of IPF.

MMP-7 is a predictive biomarker of disease progression in patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease with poor prognosis, which is characterised by destruction of normal lung architecture and excessive deposition of lung extracellular matrix. The heterogeneity of disease progression in patients with IPF poses significant obstacles to patient care and prevents efficient development of novel therapeutic interventions. Blood biomarkers, reflecting pathobiological processes in the lung, could provide objective evidence of the underlying disease. Longitudinally collected serum samples from the Bosentan Use in Interstitial Lung Disease (BUILD)-3 trial were used to measure four biomarkers (metalloproteinase-7 (MMP-7), Fas death receptor ligand, osteopontin and procollagen type I C-peptide), to assess their potential prognostic capabilities and to follow changes during disease progression in patients with IPF. In baseline BUILD-3 samples, only MMP-7 showed clearly elevated protein levels compared with samples from healthy controls, and further investigations demonstrated that MMP-7 levels also increased over time. Baseline levels of MMP-7 were able to predict patients who had higher risk of worsening and, notably, baseline levels of MMP-7 could predict changes in FVC as early as month 4. MMP-7 shows potential to be a reliable predictor of lung function decline and disease progression.

Idiopathic Pulmonary Fibrosis: Diagnosis and Clinical Manifestations

Idiopathic pulmonary fibrosis (IPF) is a parenchymal lung disease characterized by progressive interstitial fibrosis. The clinical course of IPF can be unpredictable and may be punctuated by acute exacerbations. Although much progress is being made in unraveling the mechanisms underlying IPF, effective therapy for improving survival remains elusive. Longitudinal disease profiling, especially in terms of clinical manifestations in a large cohort of patients, should lead to proper management of the patients and development of new treatments for IPF. Appropriate multidisciplinary assessment in ongoing registries is required to achieve this. This review summarizes the current status of the diagnosis and clinical manifestations of IPF.

Secreted Phosphoprotein 1 and Sex-Specific Differences in Silica-Induced Pulmonary Fibrosis in Mice

BACKGROUND

Fibrotic lung diseases occur predominantly in males, and reports describe better survival in affected females. Male mice are more sensitive to silica-induced lung fibrosis than silica-treated female mice. Secreted phosphoprotein 1 (SPP1, also known as osteopontin) increases in pulmonary fibrosis, and Spp1 transcription may be regulated by estrogen or estrogen receptor-related receptors.

OBJECTIVE

We determined whether differences in silica-induced SPP1 levels contribute to sex differences in lung fibrosis.

METHODS

Male and female mice were treated with 0.2 g/kg intratracheal silica, and lung injury was assessed 1, 3, or 14 days post-exposure. Gene-targeted (Spp1-/-) mice, control Spp1+/+ (C57BL/6J) mice, ovariectomized (OVX) female mice, and estrogen-treated male mice were treated with silica, and lung injury was assessed.

RESULTS

Silica-induced SPP1 in lung tissue, bronchoalveolar lavage, and serum increased more in male than in female mice. Following silica treatment, bronchoalveolar lavage cell infiltrates decreased in female Spp1-/- mice compared with female Spp1+/+ mice, and lung hydroxyproline decreased in male Spp1-/- mice compared with male Spp1+/+ mice. OVX female mice had increased lung SPP1 expression in response to silica compared with silica-treated sham female mice. Silica-induced lung collagen and hydroxyproline (markers of fibrosis), and SPP1 levels decreased in estrogen-treated males compared with untreated males.

CONCLUSION

These findings suggest that sex-specific differences in SPP1 levels contribute to the differential sensitivity of male and female mice to the development of silica-induced fibrosis.

CITATION

Latoche JD, Ufelle AC, Fazzi F, Ganguly K, Leikauf GD, Fattman CL. 2016. Secreted phosphoprotein 1 and sex-specific differences in silica-induced pulmonary fibrosis in mice. Environ Health Perspect 124:1199-1207; http://dx.doi.org/10.1289/ehp.1510335.

Utility of Plasma Osteopontin Levels in Management of Community-Acquired Pneumonia

Osteopontin (OPN) is an essential cytokine involved in immune cell recruitment and an important regulator of inflammation. The purpose of this study was to examine differences in OPN plasma levels between before and after antibiotic treatment in hospitalized adult patients with community-acquired pneumonia (CAP). OPN levels were measured in 93 patients with CAP and 54 healthy controls using a commercial enzyme-linked immunosorbent assay (ELISA). The CURB-65, Pneumonia Severity Index (PSI), and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores were used to determine the CAP severity in patients upon initial hospitalization. A decline in the number of white blood cells (WBCs) and neutrophils, and decreases in the levels of OPN and C-reactive protein (CRP) were observed after antibiotic treatment. Only the plasma level of OPN, but not CRP, was correlated with the severity of CAP based on the PSI (r = 0.514, p < 0.001), CURB-65 (r = 0.396, p < 0.001), and APACHE II scores (r = 0.473, p < 0.001). The OPN level also showed a significant correlation with the length of hospital stay (r = 0.210, p = 0.044). In conclusion, plasma level of OPN may act as diagnostic adjuvant biomarkers for CAP and further play a role in clinical assessment of the severity of CAP, which could potentially guide the development of treatment strategies.

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.

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.

Chemokine (C-C motif) ligand 3 detection in the serum of persons exposed to asbestos: A patient-based study

Exposure to asbestos results in serious risk of developing lung and mesothelial diseases. Currently, there are no biomarkers that can be used to diagnose asbestos exposure. The purpose of the present study was to determine whether the levels or detection rate of chemokine (C-C motif) ligand 3 (CCL3) in the serum are elevated in persons exposed to asbestos. The primary study group consisted of 76 healthy subjects not exposed to asbestos and 172 healthy subjects possibly exposed to asbestos. The secondary study group consisted of 535 subjects possibly exposed to asbestos and diagnosed with pleural plaque (412), benign hydrothorax (10), asbestosis (86), lung cancer (17), and malignant mesothelioma (10). All study subjects who were possibly exposed to asbestos had a certificate of asbestos exposure issued by the Japanese Ministry of Health, Labour and Welfare. For the primary study group, levels of serum CCL3 did not differ between the two groups. However, the detection rate of CCL3 in the serum of healthy subjects possibly exposed to asbestos (30.2%) was significantly higher (P < 0.001) than for the control group (6.6%). The pleural plaque, benign hydrothorax, asbestosis, and lung cancer groups had serum CCL3 levels and detection rates similar to that of healthy subjects possibly exposed to asbestos. The CCL3 chemokine was detected in the serum of 9 of the 10 patients diagnosed with malignant mesothelioma. Three of the patients with malignant mesothelioma had exceptionally high CCL3 levels. Malignant mesothelioma cells from four biopsy cases and an autopsy case were positive for CCL3, possibly identifying the source of the CCL3 in the three malignant mesothelioma patients with exceptionally high serum CCL3 levels. In conclusion, a significantly higher percentage of healthy persons possibly exposed to asbestos had detectable levels of serum CCL3 compared to healthy unexposed control subjects.

Results of the 4th scientific workshop of the ECCO (Group II): markers of intestinal fibrosis in inflammatory bowel disease

The fourth scientific workshop of the European Crohn's and Colitis Organization (ECCO) focused on intestinal fibrosis in inflammatory bowel disease (IBD). The objective was to better understand basic mechanisms and markers of intestinal fibrosis as well as to suggest new therapeutic targets to prevent or treat fibrosis. The results of this workshop are presented in three separate manuscripts. This section describes markers of fibrosis in IBD, identifies unanswered questions in the field and provides a framework for future studies addressing the unmet needs in the field of intestinal fibrosis.

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.

Cartilage oligomeric matrix protein in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive and life threatening disease with median survival of 2.5-3 years. The IPF lung is characterized by abnormal lung remodeling, epithelial cell hyperplasia, myofibroblast foci formation, and extracellular matrix deposition. Analysis of gene expression microarray data revealed that cartilage oligomeric matrix protein (COMP), a non-collagenous extracellular matrix protein is among the most significantly up-regulated genes (Fold change 13, p-value <0.05) in IPF lungs. This finding was confirmed at the mRNA level by nCounter® expression analysis in additional 115 IPF lungs and 154 control lungs as well as at the protein level by western blot analysis. Immunohistochemical analysis revealed that COMP was expressed in dense fibrotic regions of IPF lungs and co-localized with vimentin and around pSMAD3 expressing cells. Stimulation of normal human lung fibroblasts with TGF-β1 induced an increase in COMP mRNA and protein expression. Silencing COMP in normal human lung fibroblasts significantly inhibited cell proliferation and negatively impacted the effects of TGF-β1 on COL1A1 and PAI1. COMP protein concentration measured by ELISA assay was significantly increased in serum of IPF patients compared to controls. Analysis of serum COMP concentrations in 23 patients who had prospective blood draws revealed that COMP levels increased in a time dependent fashion and correlated with declines in force vital capacity (FVC). Taken together, our results should encourage more research into the potential use of COMP as a biomarker for disease activity and TGF-β1 activity in patients with IPF. Hence, studies that explore modalities that affect COMP expression, alleviate extracellular matrix rigidity and lung restriction in IPF and interfere with the amplification of TGF-β1 signaling should be persuaded.

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.

Plasma osteopontin levels are associated with disease activity in the patients with multiple sclerosis and neuromyelitis optica

Osteopontin (OPN) up-regulates pro-inflammatory cytokines from both T helper type 1 and T helper type 17 cell pathways. We measured plasma OPN levels in Japanese multiple sclerosis (MS) and neuromyelitis optica (NMO) patients to investigate its value as a potential biomarker of disease activity. In NMO patients, plasma OPN levels were significantly higher than those in healthy individuals, being equivalent to those in MS patients. In both NMO and MS patients, OPN levels were significantly higher during relapse compared with remission. There was also a significant positive correlation between Expanded Disability Status Scale of Kurzke scores and plasma OPN levels in both NMO and MS patients, and plasma OPN levels were significantly higher in patients with secondary progressive MS compared with those with relapsing-remitting MS. Diagnostic sensitivity and specificity of plasma OPN for MS and NMO during the relapse phase were 100% and 50%, respectively (cut-off point: 31.3ng/ml). Thus, elevated plasma OPN levels could be a potential biomarker for not only MS but also NMO. These are the first results to suggest that plasma OPN in NMO patients may be a useful marker, playing an important role in inflammation, disease activity, and disease progression, as well as MS.

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.

Mesothelioma - Update on Diagnostic Strategies

Malignant pleural mesothelioma (MPM) can be a challenging diagnosis for clinicians to make as it is often difficult to distinguish from benign asbestos pleural effusions and metastatic carcinomas. In this review, we present a case of MPM and discuss clinical manifestations, traditional diagnostic techniques, and the role of cytopathologic immunostains and serum biomarkers in the diagnosis of MPM.

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.

Plasma versus serum levels of osteopontin and mesothelin in patients with malignant mesothelioma--which is best?

BACKGROUND

Blood-based markers for malignant mesothelioma (MM), particularly soluble mesothelin and osteopontin, are currently of great clinical interest. As there is some concern about the sensitivity of osteopontin in serum versus plasma, we compared them in the same patient population to mesothelin.

METHODS

Soluble mesothelin and osteopontin concentrations were determined by commercial assays in blood samples from 66 patients with pleural MM, 47 patients with non-malignant asbestos-related lung or pleural disease, 42 patients with other benign pleural and lung diseases and 21 patients with lung cancer.

RESULTS

Soluble mesothelin and osteopontin in serum and plasma were significantly elevated in MM patients compared to patients with benign lung and pleural disease. At a level of specificity of 95% relative to patients with benign disease, the sensitivity of mesothelin in serum and plasma at presentation with symptoms was 67%, and for osteopontin in the plasma was 40% and in the serum was 20% for MM patients. Combining the serum mesothelin and plasma osteopontin markers using a logistic regression model did not significantly increase the area under the receiver operator curve.

CONCLUSION

Plasma osteopontin has a superior diagnostic accuracy to serum. As the choice of blood sample type has limit effect on soluble mesothelin sensitivity, plasma should be collected for biomarker evaluation in patients suspected of having mesothelioma.

Osteopontin levels are elevated in patients with eosinophilic pneumonia

BACKGROUND AND OBJECTIVE

Osteopontin is a key cytokine involved in pro-inflammatory T helper type 1 (Th1)-associated immune responses, which has recently been implicated in allergic diseases. We investigated the pathogenic role of osteopontin in eosinophilic pneumonia.

METHODS

The concentrations of osteopontin and Th1- or Th2-associated cytokines were measured in BAL fluid (BALF) from 41 patients with eosinophilic pneumonia, including those with acute (AEP, n = 12), chronic (CEP, n = 16), or drug-induced eosinophilic pneumonia (DEP, n = 13). The results were compared with those from patients with other interstitial lung diseases. Immunocytochemistry and double immunofluorescence labelling were performed to determine the cellular source of osteopontin.

RESULTS

Osteopontin was significantly elevated in BALF from patients with eosinophilic pneumonia as compared with BALF from patients with drug-induced interstitial pneumonia, hypersensitivity pneumonitis, idiopathic interstitial pneumonia, or sarcoidosis, and also compared with BALF from healthy volunteers. Osteopontin concentrations elevated at the time of exacerbation decreased during clinical improvement, either spontaneously or as a result of corticosteroid therapy. Elevated concentrations of CXCL10, CCL17 and IL-10 were also detected in BALF from patients with eosinophilic pneumonia. Osteopontin concentrations in BALF of AEP patients were correlated with IL-5, as well as IL-10, CCL11, CCL17 and CXCL10 concentrations. In AEP and DEP patients, serum osteopontin concentrations were also elevated. Double immunofluorescence labelling showed that in patients with eosinophilic pneumonia, osteopontin was expressed in lung eosinophils.

CONCLUSIONS

Osteopontin is likely to contribute to the development of inflammation in patients with eosinophilic pneumonia.

Effect of an immunotoxin to folate receptor beta on bleomycin-induced experimental pulmonary fibrosis

It has been suggested that alveolar and interstitial macrophages play a key role in the pathogenesis of idiopathic pulmonary fibrosis (IPF) by producing proinflammatory and/or fibrogenic cytokines. We showed that inflammatory macrophages expressed folate receptor beta (FRbeta) while resident macrophages in normal tissues expressed no or low levels of FRbeta. In the present study, we examined the distribution of FRbeta-expressing macrophages in the lungs of patients with usual idiopathic pulmonary fibrosis (UIP) and mice with bleomycin-induced pulmonary fibrosis (PF) and tested whether the depletion of FRbeta-expressing macrophages could suppress bleomycin-induced PF in mice. Immunostaining with anti-human or -mouse FRbeta monoclonal antibody (mAb) revealed that FRbeta-expressing macrophages were present predominantly in fibrotic areas of the lungs of patients with UIP and mice with bleomycin-induced PF. Intranasal administration of a recombinant immunotoxin, consisting of immunoglobulin heavy and light chain Fv portions of an anti-mouse FRbeta mAb and truncated Pseudomonas exotoxin A, increased survival significantly and reduced levels of total hydroxyproline and fibrosis in bleomycin-induced PF. In immunohistochemical analysis, decreased numbers of tumour necrosis factor-alpha-, chemokines CCL2- and CCL12-producing cells were observed in the immunotoxin-treated group. These findings suggest a pathogenic role of FRbeta-expressing macrophages in IPF. Thus, targeting FRbeta-expressing macrophages may be a promising treatment of IPF.

Osteopontin and the skin: multiple emerging roles in cutaneous biology and pathology

Osteopontin (OPN) is a glycoprotein expressed by various tissues and cells. The existence of variant forms of OPN as a secreted (sOPN) and intracellular (iOPN) protein and its modification through post-translational modification and proteolytic cleavage explain its broad range of functions. There is increasing knowledge which receptors OPN isoforms can bind to and which signaling pathways are activated to mediate different OPN functions. sOPN interacts with integrins and CD44, mediates cell adhesion, migration and tumor invasion, and has T helper 1 (Th1) cytokine functions and anti-apoptotic effects. iOPN has been described to regulate macrophage migration and interferon-alpha secretion in plasmacytoid dendritic cells. Both sOPN and iOPN, through complex functions for different dendritic cell subsets, participate in the regulation of Th cell lineages, among them Th17 cells. For skin disease, OPN from immune cells and tumor cells is of pathophysiological relevance. OPN is secreted in autoimmune diseases such as lupus erythematosus, and influences inflammation of immediate and delayed type allergies and granuloma formation. We describe that OPN is overexpressed in psoriasis and propose a model to study OPN function in psoriatic inflammation. Through cytokine functions, OPN supports immune responses against Mycobacteria and viruses such as herpes simplex virus. OPN is also implicated in skin tumor progression. Overexpression of OPN influences invasion and metastasis of melanoma and squamous cell carcinoma cells, and OPN expression in melanoma is a possible prognostic marker. As OPN protein preparations and anti-OPN antibodies may be available in the near future, in-depth knowledge of OPN functions may open new therapeutic approaches for skin diseases.

Spectrum of fibrosing diffuse parenchymal lung disease

The interstitial lung diseases are a heterogeneous group of disorders characterized by inflammation and/or fibrosis of the pulmonary interstitium. In 2002, the American Thoracic Society and the European Respiratory Society revised the classification of interstitial lung diseases and introduced the term diffuse parenchymal lung disease. The idiopathic interstitial pneumonias are a subtype of diffuse parenchymal lung disease. The idiopathic interstitial pneumonias are subdivided into usual interstitial pneumonia (with its clinical counterpart idiopathic interstitial pneumonia), nonspecific interstitial pneumonia, cryptogenic organizing pneumonia, acute interstitial pneumonia, desquamative interstitial pneumonia, respiratory bronchiolitis interstitial lung disease, and lymphocytic pneumonia. Sarcoidosis and hypersensitivity pneumonitis are the 2 most common granulomatous diffuse parenchymal lung diseases. Rheumatoid arthritis, systemic sclerosis, and dermatomyositis/polymyositis (causing antisynthetase syndrome) are diffuse parenchymal lung diseases of known association because these conditions are associated with connective tissue disease. Hermansky-Pudlak syndrome is a rare genetic diffuse parenchymal lung disease characterized by the clinical triad of pulmonary disease, oculocutaneous albinism, and bleeding diathesis. This review provides an overview of the chronic fibrosing diffuse parenchymal lung diseases. Its primary objective is to illuminate the clinical challenges encountered by clinicians who manage the diffuse parenchymal lung diseases regularly and to offer potential solutions to those challenges. Treatment for the diffuse parenchymal lung diseases is limited, and for many patients with end-stage disease, lung transplantation remains the best option. Although much has been learned about the diffuse parenchymal lung diseases during the past decade, research in these diseases is urgently needed.

Osteopontin is upregulated in malignant and inflammatory pleural effusions

BACKGROUND AND OBJECTIVE

Osteopontin (OPN) is an important mediator of inflammation and cancer progression. In the present study, we asked whether pleural fluid (PF) and serum OPN concentrations differed between patients with pleural effusions of different aetiologies, and whether assessment of OPN levels was useful for diagnostic purposes.

METHODS

One hundred and nine consecutive patients with pleural effusions of different aetiologies were recruited prospectively during daily clinics. OPN levels were measured by ELISA.

RESULTS

PF OPN levels were 10-fold higher in exudates than in transudates and were significantly correlated with markers of pleural inflammation and vascular hyper-permeability, such as PF/serum LDH or protein ratios, PF protein and PF vascular endothelial growth factor levels. Patients with malignant pleural effusions had higher PF and lower serum OPN concentrations than those with benign disease. The diagnostic accuracies of PF and PF/serum OPN for malignancy were 71.5% (95% CI: 64-80) and 70.6% (95% CI: 62-80), respectively.

CONCLUSIONS

OPN levels were elevated in exudative pleural effusions, as compared with the levels in blood or transudative pleural effusions. While PF and PF/serum OPN were higher in patients with malignancies, the diagnostic accuracy of the tests was not sufficient to permit routine use in clinical practice.

Molecular phenotypes distinguish patients with relatively stable from progressive idiopathic pulmonary fibrosis (IPF)

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive, chronic interstitial lung disease that is unresponsive to current therapy and often leads to death. However, the rate of disease progression differs among patients. We hypothesized that comparing the gene expression profiles between patients with stable disease and those in which the disease progressed rapidly will lead to biomarker discovery and contribute to the understanding of disease pathogenesis.

METHODOLOGY AND PRINCIPAL FINDINGS

To begin to address this hypothesis, we applied Serial Analysis of Gene Expression (SAGE) to generate lung expression profiles from diagnostic surgical lung biopsies in 6 individuals with relatively stable (or slowly progressive) IPF and 6 individuals with progressive IPF (based on changes in DLCO and FVC over 12 months). Our results indicate that this comprehensive lung IPF SAGE transcriptome is distinct from normal lung tissue and other chronic lung diseases. To identify candidate markers of disease progression, we compared the IPF SAGE profiles in stable and progressive disease, and identified a set of 102 transcripts that were at least 5-fold up regulated and a set of 89 transcripts that were at least 5-fold down regulated in the progressive group (P-value</=0.05). The over expressed genes included surfactant protein A1, two members of the MAPK-EGR-1-HSP70 pathway that regulate cigarette-smoke induced inflammation, and Plunc (palate, lung and nasal epithelium associated), a gene not previously implicated in IPF. Interestingly, 26 of the up regulated genes are also increased in lung adenocarcinomas and have low or no expression in normal lung tissue. More importantly, we defined a SAGE molecular expression signature of 134 transcripts that sufficiently distinguished relatively stable from progressive IPF.

CONCLUSIONS

These findings indicate that molecular signatures from lung parenchyma at the time of diagnosis could prove helpful in predicting the likelihood of disease progression or possibly understanding the biological activity of IPF.

Regulation of T-helper-cell lineage development by osteopontin: the inside story

Studies of osteopontin (OPN)-dependent regulation of immune responses have focused on the cytokine activities of the secreted form of this protein. Recent evidence has revealed that an intracellular form of OPN expressed by dendritic cells regulates the expression of pro-inflammatory cytokines and the differentiation of T helper (T(H))-cell lineages. In this Opinion article, we discuss the properties of both OPN isoforms and their respective contributions to the immune response. We propose that cell-type-specific expression of secreted and intracellular OPN regulates the development of distinct effector T(H) cells, including that of T(H)1 and T(H)17 cells.

Comprehensive study on the prognostic role of osteopontin expression in oral squamous cell carcinoma

Osteopontin is a tumor-associated protein that promotes tumor development and metastasis. The preoperative blood samples of 94 oral squamous cell carcinoma (OSCC) patients and 28 healthy individuals were analyzed for plasma osteopontin levels, and another 256 paraffin-embedded OSCC specimens were analyzed by osteopontin immunostaining. The patients with advanced tumor (T) stage (T3/T4 vs. T1/T2) and positive nodal (N) status had significantly higher plasma levels of osteopontin (both p<0.001). Positive osteopontin immunostaining also correlated significantly with advanced T stage (p<0.001), positive N status (p<0.001), advanced TNM stage (p<0.001) and male gender (p=0.016). Unfavorable cumulative 5-year overall survival rates correlated significantly with positive osteopontin immunostaining (p<0.001), advanced T stage (p<0.001), positive N status (p<0.001) and advanced TNM stage (p<0.001). However, Cox regression analysis revealed that T stage and N status were independent prognostic factors for survival (both p<0.001) and osteopontin immunostaining was marginally significant for survival (p=0.056). The present study demonstrated that high expression level of osteopontin in either the plasma or the tumor of the patients with OSCC was associated with tumor progression, suggesting that osteopontin expression is an important prognostic factor for OSCC.

Comparison of osteopontin, megakaryocyte potentiating factor, and mesothelin proteins as markers in the serum of patients with malignant mesothelioma

INTRODUCTION

There is increasing interest in identifying a blood-based marker for the asbestos-related tumor, malignant mesothelioma. Three potential markers for mesothelioma are mesothelin, megakaryocyte potentiating factor (MPF) and osteopontin. The purpose of the current study was to directly compare these biomarkers in the same sample population, determining their sensitivity and specificity in establishing a diagnosis, and to determine if diagnostic accuracy for mesothelioma is improved by combining the data from all three markers.

METHODS

Serum levels of mesothelin, MPF and osteopontin were determined by commercially available assays in 66 samples from patients with pleural malignant mesothelioma, 20 healthy individuals, 21 patients with asbestos-related lung or pleural disease, 30 patients presenting with benign pleural effusions and 30 patients with other malignancies.

RESULTS

Serum levels of the three markers were elevated in mesothelioma patients. At a level of specificity of 95% relative to healthy controls and patients with benign asbestos related disease, the sensitivity for mesothelioma was 34% for MPF, 47% for osteopontin and 73% for mesothelin. Osteopontin and MPF were unable to differentiate patients with mesothelioma from patients with other malignancies or those presenting with transudative pleural effusions. Combining the data from the three biomarkers using a logistic regression model did not improve sensitivity for detecting mesothelioma above that of the mesothelin marker alone.

CONCLUSION

Serum mesothelin remains the most specific marker for the diagnosis of mesothelioma.

A blood test for lung fibrosis

Peter Barnes discusses a new study on the role of two matrix metalloproteinases, MMP1 (collagenase) and MMP7 (matrilysin), as possible biomarkers of idiopathic pulmonary fibrosis.

MMP1 and MMP7 as potential peripheral blood biomarkers in idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive fibrotic lung disease associated with substantial morbidity and mortality. The objective of this study was to determine whether there is a peripheral blood protein signature in IPF and whether components of this signature may serve as biomarkers for disease presence and progression.

METHODS AND FINDINGS

We analyzed the concentrations of 49 proteins in the plasma of 74 patients with IPF and in the plasma of 53 control individuals. We identified a combinatorial signature of five proteins-MMP7, MMP1, MMP8, IGFBP1, and TNFRSF1A-that was sufficient to distinguish patients from controls with a sensitivity of 98.6% (95% confidence interval [CI] 92.7%-100%) and specificity of 98.1% (95% CI 89.9%-100%). Increases in MMP1 and MMP7 were also observed in lung tissue and bronchoalveolar lavage fluid obtained from IPF patients. MMP7 and MMP1 plasma concentrations were not increased in patients with chronic obstructive pulmonary disease or sarcoidosis and distinguished IPF compared to subacute/chronic hypersensitivity pneumonitis, a disease that may mimic IPF, with a sensitivity of 96.3% (95% CI 81.0%-100%) and specificity of 87.2% (95% CI 72.6%-95.7%). We verified our results in an independent validation cohort composed of patients with IPF, familial pulmonary fibrosis, subclinical interstitial lung disease (ILD), as well as with control individuals. MMP7 and MMP1 concentrations were significantly higher in IPF patients compared to controls in this cohort. Furthermore, MMP7 concentrations were elevated in patients with subclinical ILD and negatively correlated with percent predicted forced vital capacity (FVC%) and percent predicted carbon monoxide diffusing capacity (DLCO%).

CONCLUSIONS

Our experiments provide the first evidence for a peripheral blood protein signature in IPF to our knowledge. The two main components of this signature, MMP7 and MMP1, are overexpressed in the lung microenvironment and distinguish IPF from other chronic lung diseases. Additionally, increased MMP7 concentration may be indicative of asymptomatic ILD and reflect disease progression.

Immunohistochemical detection of osteopontin in advanced head-and-neck cancer: Prognostic role and correlation with oxygen electrode measurements, hypoxia-inducible-factor-1α-related markers, and hemoglobin levels

PURPOSE

The tumor-associated glycoprotein osteopontin (OPN) is discussed as a plasma marker of tumor hypoxia. However, the association of immunohistochemical OPN expression in tumor sections with tumor oxygenation parameters (HF5, median pO(2)), the hypoxia-related markers hypoxia-inducible factor-1alpha (HIF-1alpha) and carbonic anhydrase IX (CAIX), or hemoglobin and systemic vascular endothelial growth factor (VEGF) levels has not been investigated.

METHODS AND MATERIALS

Tumor tissue sections of 34 patients with advanced head-and-neck cancer treated with radiotherapy were assessed by immunochemistry for the expression of OPN, HIF-1alpha, and CA IX. Relationship of OPN expression with tumor oxygenation parameters (HF5, median pO(2)), HIF-1alpha and CA IX expression, hemoglobin and serum VEGF level, and clinical parameters was studied.

RESULTS

Bivariate analysis showed a significant correlation of positive OPN staining with low hemoglobin level (p = 0.02), high HIF-1alpha expression (p = 0.02), and high serum vascular endothelial growth factor level (p = 0.02) for advanced head-and-neck cancer. Furthermore, considering the 31 Stage IV patients, the median pO(2) correlated significantly with the OPN expression (p = 0.02). OPN expression alone had only a small impact on prognosis. However, in a univariate Cox proportional hazard regression model, the expression of either OPN or HIF-1alpha or CA IX was associated with a 4.1-fold increased risk of death (p = 0.02) compared with negativity of all three markers.

CONCLUSION

Osteopontin expression detected immunohistochemically is associated with oxygenation parameters in advanced head-and-neck cancer. When the results of OPN, HIF-1alpha, and CA IX immunohistochemistry are combined into a hypoxic profile, a strong and statistically significant impact on overall survival is found.

Plasma osteopontin levels in patients with head and neck cancer and cervix cancer are critically dependent on the choice of ELISA system

BACKGROUND

The tumor-associated glycoprotein osteopontin (OPN) is discussed as a plasma surrogate marker of tumor hypoxia and as an indicator of the presence of pleural mesothelioma in asbestos-exposed individuals. The clinical introduction of plasma OPN measurements requires the availability of a reliable enzyme-linked immunosorbence assay (ELISA).

METHODS

We compared previously described and currently available ELISA systems on 88 archival plasma samples obtained from patients with head and neck or cervix cancer between 20 days before and 171 after the start of radiotherapy.

RESULTS

Median (range) plasma OPN levels were 667 (148.8-2095) ng/ml and 9.8 (3.5-189.5) ng/ml for a previously described and a newly marketed assay, respectively. Although results for different assays were significantly correlated (r = 0.38, p < 0.05, Spearman rank test), between-assay factors ranged from 2.0 to 217.9 (median 74.6) in individual patients. OPN levels in cervix cancer patients were comparable to those of head and neck cancer patients.

CONCLUSION

Commercially available OPN ELISA systems produce different absolute plasma OPN levels, compromising a comparison of individual patient data with published results. However, different assays appear to have a similar capacity to rank patients according to plasma OPN level. A review of literature data suggests that plasma OPN levels measured even with identical ELISA systems can only be compared with caution.

Gene expression profiling as a window into idiopathic pulmonary fibrosis pathogenesis: can we identify the right target genes?

Expression microarrays that provide genome-level, transcriptional, high-resolution profiles have been applied successfully to multiple diseases. Although microarrays provide information regarding thousands of genes, many investigators prefer to focus on a single gene and validate its role, an approach often supported by grant and journal reviewers. Only a minority of investigators focus on global changes in gene expression. Here, we describe and contrast two general approaches to the use of microarray data: the reductionist "cherry picking" approach and the more global, quantitative "systems" approach. We describe microarray analysis experiments relevant to idiopathic pulmonary fibrosis (IPF) in the context of these two approaches. Although it seems that the cherry-picking approaches have been successful in identifying new relevant genes in IPF, we suggest that to fulfill the discovery potential of microarrays in IPF and to create a working model of IPF, unbiased integrative systems approaches are required.