Serological biomarkers of type I, III and IV collagen turnover are associated with the presence and future progression of stricturing and penetrating Crohnʼs disease

Summary Background Increased collagen remodelling is a key pathophysiological component underlying intestinal stricture and fistula development in Crohn's disease (CD). Aims To investigate associations between serological biomarkers of collagen turnover and disease behaviour according to the Montreal classification in patients with CD. Methods Serological biomarkers of type III/IV collagen formation (PRO‐C3, PRO‐C4) and matrix metalloproteinase (MMP) or granzyme‐B (GrzB)‐mediated type I, III, IV and VI collagen degradation (C1M, C3M, C4M, C4G, C6Ma3) were measured using neo‐epitope protein fingerprint assays in 101 patients with CD (Montreal B1: n = 37; B2: n = 27; B3: n = 37) and 96 controls. Patients were followed up until their last outpatient visit to monitor stricturing/penetrating disease progression and recurrence and the occurrence of surgical interventions. Results C1M, C3M and C4M were significantly reduced in patients with stricturing disease (Montreal B2) and accurately differentiated them from patients with either non‐stricturing, non‐penetrating (B1) or penetrating (B3) disease (all p