Atorvastatin increases myocardial indices of oxidative stress in a porcine model of hypercholesterolemia and chronic ischemia.

BACKGROUND/AIM: Atorvastatin has previously been shown to reduce the endogenous angiogenic response to chronic ischemia in a porcine model. One possible mechanism for this effect is reduced bioavailability of nitric oxide, a key mediator of angiogenesis, secondary to increased oxygen free radicals. We sought to determine if atorvastatin modulates oxidative stress in myocardial tissue.

METHODS

Dietary induction of hypercholesterolemia was performed over 20 weeks in Yucatan swine with treated animals receiving atorvastatin 3 mg/kg/day. Chronic myocardial ischemia was induced via surgical placement of an ameroid constrictor ring around the proximal circumflex artery at age 20 weeks, followed by tissue harvest at age 27 weeks. Myocardial levels of protein, lipid, and DNA biomarkers of oxidative stress, serum levels of 8-isoprostane, nitric oxide (NO) dependent, and independent coronary microvascular reactivity, as well as isotope-labeled microsphere myocardial perfusion analysis and histologic analysis for endothelial cell density was performed.

RESULTS

Atorvastatin treatment was associated with elevated levels of myocardial protein oxidation and lipid peroxidation. Conversely, serum oxidant stress biomarkers were not elevated. Atorvastatin treatment improved nitric oxide dependent and independent microvascular reactivity, and was associated with decreased perfusion in the ischemic myocardial territory.

CONCLUSION

Treatment with atorvastatin was associated with increased levels of myocardial tissue protein and lipid oxidative stress biomarkers and a reduced functional endogenous angiogenic response, but improved coronary microvascular reactivity. Increased oxidative stress in tissues may play a role in the reduced angiogenic response seen with atorvastatin treatment in other studies.