Decreased Expression of Canstatin in Rat Model of Monocrotaline-Induced Pulmonary Arterial Hypertension: Protective Effect of Canstatin on Right Ventricular Remodeling.

Pulmonary arterial hypertension (PAH) is a progressive disease which causes right ventricular (RV) failure. Canstatin, a C-terminal fragment of type IV collagen alpha 2 chain, is expressed in various rat organs. However, the expression level of canstatin in plasma and organs during PAH is still unclear. We aimed to clarify it and further investigated the protective effects of canstatin in a rat model of monocrotaline-induced PAH. Cardiac functions were assessed by echocardiography. Expression levels of canstatin in plasma and organs were evaluated by enzyme-linked immunosorbent assay and Western blotting, respectively. PAH was evaluated by catheterization. RV remodeling was evaluated by histological analyses. Real-time polymerase chain reaction was performed to evaluate RV remodeling-related genes. The plasma concentration of canstatin in PAH rats was decreased, which was correlated with a reduction in acceleration time/ejection time ratio and an increase in RV weight/body weight ratio. The protein expression of canstatin in RV, lung and kidney was decreased in PAH rats. While recombinant canstatin had no effect on PAH, it significantly improved RV remodeling, including hypertrophy and fibrosis, and prevented the increase in RV remodeling-related genes. We demonstrated that plasma canstatin is decreased in PAH rats and that administration of canstatin exerts cardioprotective effects.