MMP1 and hypertrophic cardiomyopathy: In more recent studies, Yang et al. observed correlations between PICP and MMP-2 levels with CVF in hypertrophic cardiomyopathy (HCM) patients, whereas Ravassa et al. showed that the ratio of CITP/MMP-1 and PICP were associated with biopsy-proven fibrosis in hypertensive HF patients [25,26].