The Effects and Mechanism of Atorvastatin on Pulmonary Hypertension Due to Left Heart Disease

BACKGROUND: Pulmonary hypertension due to left heart disease (PH-LHD) is one of the most common forms of PH, termed group 2 PH. Atorvastatin exerts beneficial effects on the structural remodeling of the lung in ischemic heart failure. However, few studies have investigated the effects of atorvastatin on PH due to left heart failure induced by overload. METHODS: Group 2 PH was induced in animals by aortic banding. Rats (n = 20) were randomly divided into four groups: a control group (C), an aortic banding group (AOB(63)), an atorvastatin prevention group (AOB(63)/ATOR(63)) and an atorvastatin reversal group (AOB(63)/ATOR(50-63)). Atorvastatin was administered for 63 days after banding to the rats in the AOB(63)/ATOR(63) group and from days 50 to 63 to the rats in the AOB(63)/ATOR(50-63) group. RESULTS: Compared with the controls, significant increases in the mean pulmonary arterial pressure, pulmonary arteriolar medial thickening, biventricular cardiac hypertrophy, wet and dry weights of the right middle lung, percentage of PCNA-positive vascular smooth muscle cells, inflammatory infiltration and expression of RhoA and Rho-kinase II were observed in the AOB(63) group, and these changes concomitant with significant decreases in the percentage of TUNEL-positive vascular smooth muscle cells. Treatment of the rats in the AOB(63)/ATOR(63) group with atorvastatin at a dose of 10 mg/kg/day significantly decreased the mean pulmonary arterial pressure, right ventricular hypertrophy, pulmonary arteriolar medial thickness, inflammatory infiltration, percentage of PCNA-positive cells and pulmonary expression of RhoA and Rho-kinase II and significantly augmented the percentage of TUNEL-positive cells compared with the AOB(63) group. However, only a trend of improvement in pulmonary vascular remodeling was detected in the AOB(63)/ATOR(50-63) group. CONCLUSIONS: Atorvastatin prevents pulmonary vascular remodeling in the PH-LHD model by down-regulating the expression of RhoA/Rho kinase, by inhibiting the proliferation and increasing the apoptosis of pulmonary arterial smooth muscle cells, and by attenuating the inflammation of pulmonary arteries.