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Background: Chronic obstructive pulmonary disease (COPD) is characterized by abnormal epithelial repair process that may result in intra-airway accumulation of fibrin. Given that plasma fibrinogen is the only FDA approved biomarker that predicts mortality and COPD exacerbations, we hypothesized that changes in the processing of fibrinogen may provide additional characterization of disease phenotype and COPD progression. Methods: A subpopulation of subjects with COPD, (n ¼ 983) smoker (n ¼ 205) and non-smoker controls (n ¼ 98) were included from The Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-points (ECLIPSE) cohort. Two biomarkers that specifically target the thrombin-mediated conversion of fibrinogen into fibrin (PRO-FIB), and plasmin-mediated degradation of cross-linked fibrin (X-FIB) were measured and compared with fibrinogen measurements. Results: X-FIB had a predictive value for two-year mortality, with an adjusted hazard ratio of 1.48 per SD (n ¼ 980; 95% Cl 1.18-1.84; p < 0.0001), and comparable to the fibrinogen hazard ratio of 1.59 per SD (n ¼ 983; 95% Cl 1.29-1.96; p ¼ 0.0003). X-FIB (p < 0.001), fibrinogen (p < 0.0001) and PRO-FIB (p < 0.05) were significantly elevated in symptomatic COPD (mMRC � 2) as compared to asymptomatic COPD. X-FIB was the only biomarker that was associated with emphysema (p < 0.001), and only plasma fibrinogen (p < 0.05) was associated with exacerbations. Conclusion: There is a need for biomarkers to characterize the heterogeneity of COPD, to continuously improve clinical trial design and to identify disease progressors for efficient health care utilization. Each of three fibrinogen biomarkers studied provide information representing distinct aspects of COPD which may be used to characterize disease endotypes and to assess mortality risk in COPD.

Background: Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation and lung tissue deterioration. Given the high vascularity of the lung, von Willebrand factor (VWF), a central component of wound healing initiation, has previously been assessed in COPD. VWF processing, which is crucial for regulating the primary response of wound healing, has not been assessed directly. Therefore, this study aimed to characterize wound healing initiation in COPD using dynamic VWF-processing biomarkers and to evaluate how these relate to disease severity and mortality. Methods: A cross-sectional analysis of plasma samples from the ECLIPSE study collected at year 1 from moderate to very severe COPD subjects (GOLD 2-4, n=984) was performed. We applied competitive neo-epitope ELISAs specifically targeting the formation of and ADAMTS13-processed form of VWF, VWF-N and VWF-A, respectively. Results: VWF-A and VWF-N were significantly increased (VWF-N, p=0.01; VWF-A, p=0.0001) in plasma of symptomatic (mMRC score ≥2) compared to asymptomatic/mild symptomatic COPD subjects. Increased VWF-N and VWF-A levels were specifically associated with emphysema (VWF-N, p<0.0001) or prior exacerbations (VWF-A, p=0.01). When dichotomized, high levels of both biomarkers were associated with increased risk of all-cause mortality (VWF-N, HR 3.5; VWF-A, HR 2.64). Conclusion: We demonstrate that changes in VWF processing were related to different pathophysiological aspects of COPD. VWF-N relates to the chronic condition of emphysema, while VWF-A was associated with the more acute events of exacerbations. This study indicates that VWF-A and VWF-N may be relevant markers for characterization of disease phenotype and are associated with mortality in COPD.