Objective
We sought to explore the effects of non-selective COX and selective COX-2 inhibition on collateral development in a model of chronic myocardial ischemia. We hypothesized that COX-2 inhibitors will negatively effect angiogenic and inflammatory pathways.
Methods
Yorkshire swine were made chronically ischemic by placing an ameroid constrictor on the left circumflex coronary artery. Swine were divided into three groups and given: no drug (control, n=7), a non-selective COX inhibitor (naproxen 400mg daily, NAP, n=7), or a selective COX-2 inhibitor (celecoxib 200mg daily, CBX, n=7). After 7 weeks, coronary angiography was performed. Myocardial function and microvascular reactivity were assessed. Serum and myocardial tissue were analyzed for prostaglandin levels and markers of inflammation and angiogenesis.
Results
The CBX group demonstrated significantly increased mean arterial pressure and decreased left ventricular function. Myocardial perfusion in the CBX group was similar to the control, but less than in the NAP group. Coronary microvascular contraction in the collateral dependent territory was increased in the NAP group, but minimally affected in the CBX group. Oxidative stress and apoptosis were increased in the CBX group. Expression of angiogenic markers, VEGF and phospho-eNOS (ser1177), and tissue levels of prostacyclin were decreased in both the CBX and NAP groups. The NAP group had diminished expression of endostatin.
Conclusion
The effects of selective and non-selective COX inhibition are more complex than previously published, but they do not decrease collateral dependent blood flow to the myocardium in our model of chronic myocardial ischemia.