ABSTRACT
BACKGROUND: Extracellular matrix (ECM) remodeling of the lung tissue releases protein fragments into the blood, where they may be detected as serologic surrogate markers of disease activity in COPD. Our goal was to assess the association of ECM turnover with severity and outcome of COPD. METHODS: In a prospective, observational, multicenter study including 506 patients with COPD (Global Initiative for Chronic Obstructive Lung Disease grades II to IV), serum samples were analyzed at stable state, exacerbation, and 4 weeks after exacerbation. The analysis comprised a panel of five novel neoepitopes, including fragments of collagen type III (C3M) and collagen type VI (C6M), pro-forms of collagen type III (Pro-C3) and type VI (Pro-C6), and neutrophil elastase-generated fragments of elastin (EL-NE) according to enzyme-linked immunosorbent assay. These neoepitopes were also measured at stable state in a derivation cohort that included 100 patients with COPD. RESULTS: Serum levels of C3M, C6M, Pro-C3, Pro-C6, and EL-NE were associated with lung function. Patients with the lowest levels of Pro-C3 and Pro-C6 had more severe airflow limitation, hyperinflation, air trapping, and emphysema. C3M and C6M were associated with dyspnea. All ECM biomarkers, except Pro-C6, were increased at exacerbation compared with stable state but, except EL-NE, did not differ between stable state and exacerbation follow-up in the crude and adjusted analyses. In Cox regression adjusted analyses, Pro-C3 was associated with a shorter time to exacerbation (hazard ratio, 0.72; CI, 0.59-0.89; P = .002) and Pro-C6 with survival (hazard ratio, 2.09; CI, 1.18-3.71; P = .011). CONCLUSIONS: Serum biomarkers of ECM turnover were significantly associated with disease severity and clinically relevant outcomes in patients with COPD. TRIAL REGISTRY: No.: ISRCTN99586989; URL: www.controlled-trials.com.
Subject(s)
Airway Remodeling/physiology , Collagen/metabolism , Elastin/metabolism , Pulmonary Disease, Chronic Obstructive , Aged , Biomarkers/metabolism , Disease Progression , Europe/epidemiology , Extracellular Matrix/metabolism , Female , Humans , Male , Middle Aged , Outcome Assessment, Health Care/methods , Pulmonary Disease, Chronic Obstructive/diagnosis , Pulmonary Disease, Chronic Obstructive/epidemiology , Pulmonary Disease, Chronic Obstructive/metabolism , Pulmonary Disease, Chronic Obstructive/physiopathology , Respiratory Function Tests/methods , Severity of Illness IndexABSTRACT
Despite massive investments in the development of novel treatments for heterogeneous diseases such as COPD, the resources spent have only benefited a fraction of the population treated. Personalized health care to guide selection of a suitable patient population already in the clinical development of new compounds could offer a solution. This review discusses past successes and failures in drug development and biomarker research in COPD, describes research in COPD phenotypes and the required characteristics of a suitable biomarker for identifying patients at higher risk of progression, and examines the role of extracellular matrix proteins found to be upregulated in COPD. Novel biomarkers of connective tissue remodeling that may provide added value for a personalized approach by detecting subgroups of patients with active disease suitable for pharmacologic intervention are discussed.
Subject(s)
Health Services Research , Precision Medicine , Pulmonary Disease, Chronic Obstructive/drug therapy , Pulmonary Disease, Chronic Obstructive/metabolism , Biomarkers/metabolism , Humans , Patient SelectionABSTRACT
This review discusses the role of extracellular matrix (ECM) quality in the pathogenesis of pulmonary fibrosis (PF). In PF, the highly ordered structure of collagens and elastin within the ECM of the lung is severely disrupted and lacks its original tissue quality. Discussions about the ECM have focused on the role of protein quantity in relation to the progression of PF, while the importance of lung ECM quality, defined by the levels of ECM protein modifications and by the protein distribution in lung tissue, has not been properly addressed. The quality and function of proteins may be altered by different post-translational modifications (PTMs), such as cross-linking, proteolytic cleavage, citrullination, misfolding and glycosylation. This paper is the first to review key data from the literature related to the lung ECM at the molecular level, relate these to changes observed at a macroscopic level and evaluate which PTMs most likely contribute to PF. This paper also reviews the role of novel neo-epitope-specific biomarkers in the early diagnosis and prognosis of fibrotic disorders. We discuss and argue that the altered quality of the individual ECM proteins contributes to the progression of PF and may also lead to the increased quantity of lung proteins. Thus, both quantity and quality appear to be of utmost importance.
