Cystatin C has been shown to be associated with heart failure with preserved ejection fraction (HFPEF). In addition, myocardial fibrosis has been involved in diastolic dysfunction in HFPEF. Therefore, we hypothesized that increased cystatin C levels may be associated with altered collagen metabolism, contributing to diastolic dysfunction in patients with HFPEF.
One hundred and forty-one elderly hypertensive patients with HFPEF were included. Cardiac morphology and function was assessed by echocardiography. Circulating levels of cystatin C, biomarkers of collagen type I synthesis (carboxy-terminal propeptide of procollagen type I) and degradation [matrix metalloproteinase-1 (MMP-1) and its inhibitor TIMP-1] and osteopontin were analyzed by ELISA. Twenty elderly sex-matched patients with no identifiable cardiac disease were used as controls. In-vitro studies were performed in human cardiac fibroblasts.
Compared with controls, cystatin C was increased (P¿<¿0.001) in patients with HFPEF, even in those with a normal estimated glomerular filtration rate (eGFR; P¿<¿0.05). Cystatin C was directly correlated with the estimated pulmonary capillary wedge pressure (P¿<¿0.01), TIMP-1 and osteopontin (P¿<¿0.001) and inversely correlated with MMP-1:TIMP-1 (P¿<¿0.01), but not with carboxy-terminal propeptide of procollagen type I or MMP-1 in all patients with HFPEF. These associations were independent of eGFR. In vitro, osteopontin (P¿<¿0.01) and TIMP-1 (P¿<¿0.0