ADAMTS-1 contributes to the antifibrotic effect of Captopril by accelerating the degradation of type I collagen in chronic viral myocarditis

Angiotensin-converting enzyme (ACE) inhibitors have been demonstrated to have antifibrotic activity in myocardial fibrosis. A distintegrin and metalloprotease with thrombospondin type 1 motifs (ADAMTS-1 ) is a newly discovered metalloproteinase. It was reported ADAMTS-1 had novel gelatin (type I collagen) degrading activities. We examined the role of ADAMTS-1 in the antifibrotic activity of the ACE inhibitor Captopril in a chronic viral myocarditis (CVMC) model. Balb/c mice were assigned to five groups: normal control group1 (group 1), normal control group2 (group 2), CVMC model group (group 3), CVMC control group (group 4) and Captopril therapy group (group 5). Group 3, 4 and 5 received Coxsackievirus B3 to induce CVMC and group 5 was treated with Captopril (100 mg/kg)for 28 days. Heart sections were stained with picrosirius red and collagen volume fraction calculated. ADAMTS-1 expression was determined by Western blot. Type I collagen and carboxyterminal telopeptide of type I collagen (ICTP) were measured by RT-PCR. Group 4 mice had significantly increased collagen volume fraction compared to groups 2 and 5 (P<0.001, P<0.001, respectively) and higher type I collagen mRNA expression than groups 2 and 5 (P<0.001, P<0.001, respectively). Group 5 ADAMTS-1 and ICTP expression was significantly higher than in groups 2 and 4 (P<0.001, P<0.001, respectively). ADAMTS-1 levels in group 5 negatively correlated with collagen volume fraction (r=—0.68, P<0.01) and type I collagen (r=—0.67, P<0.01) but positively correlated with ICTP (r = 0.72, P<0.01). We conclude that ADAMTS-1 contributes to the antifibrotic effect of Captopril by accelerating the degradation of type I collagen in CVMC.