Abstract
Idiopathic pulmonary fibrosis (IPF) is characterised by excessive extracellular matrix (ECM) deposition and remodelling. Measuring this activity provides an opportunity to develop tools capable of identifying individuals at risk of progression. Longitudinal change in markers of ECM synthesis was assessed in 145 newly-diagnosed individuals with IPF. Serum levels of collagen synthesis neoepitopes, PRO-C3 and PROC6 (collagen type 3 and 6), were elevated in IPF compared with controls at baseline, and progressive disease versus stable disease during follow up, (PROC3 p<0.001; PROC6 p=0.029). Assessment of rate of change in neoepitope levels from baseline to 3 months (defined as slope to month 3: HIGH slope, slope > 0 vs. LOW slope, slope <=0) demonstrated no relationship with mortality for these markers (PROC3 (HR 1.62, p=0.080); PINP (HR 0.76, p=0.309); PROC6 (HR 1.14, p=0.628)). As previously reported, rising concentrations of collagen degradation markers C1M, C3M, C6M and CRPM were associated with an increased risk of overall mortality (HR=1.84, CI 1.03 to 3.27, p=0.038, HR=2.44, CI 1.39 to 4.31, p=0.002; HR= 2.19, CI 1.25 to 3.82, p=0.006; HR= 2.13 CI 1.21 to 3.75, p=0.009 respectively). Elevated levels of PROC3 and PROC6 associate with IPF disease progression. Collagen synthesis and degradation biomarkers have the potential to enhance clinical trials in IPF and may inform prognostic assessment and therapeutic decision making in the clinic. Clinical trial registration ID #: NCT01134822 and NCT01110694.
