Rationale: the potential role of statins in treating chronic obstructive pulmonary disease (COPD) is controversial, and it is unclear what anatomic COPD lesions statins affect.
Objectives: to determine whether an intervention of simvastatin could alter cigarette smoke-induced pulmonary hypertension.
Methods: we exposed guinea pigs to cigarette smoke for 6 months. In half the animals, simvastatin therapy was initiated after 3 months of smoke exposure. Pulmonary arterial systolic pressures were monitored weekly with a radiotelemetric catheter; additional physiologic and morphologic measurements were made at sacrifice after 6 months. Precision-cut lung explants were assessed for evidence of endothelial dysfunction, and in situ vascular nitric oxide generation was measured with 4,5-diaminofluorescein diacetate.
Measurements and main results: cigarette smoke increased the pulmonary arterial systolic pressure after approximately 4 weeks. Simvastatin returned the pressure to control levels within 4 weeks of starting treatment, and ameliorated smoke-induced small arterial remodeling as well as emphysema measured both physiologically and morphometrically at 6 months, but did not prevent smoke-induced small airway remodeling either physiologically or morphologically. In precision-cut lung slices simvastatin reversed small arterial endothelial dysfunction, and partially reversed smoke-induced loss of vascular nitric oxide generation.
Conclusions: simvastatin, as an intervention therapy, reverses the pulmonary vascular effects of cigarette smoke, including pulmonary hypertension, and prevents smoke-induced emphysema, but does not prevent small airway remodeling. This is the first demonstration that an intervention can reverse a COPD-associated cigarette smoke-induced anatomic abnormality. The study also shows the importance of examining all three anatomic lung compartments when assessing the effects of a potential drug intervention in patients with COPD.