An iron-binding exochelin prevents restenosis due to coronary artery balloon injury in a porcine model.

Background- Vascular smooth muscle cell (VSMC) proliferation is a critical factor in the neointima formation that causes restenosis after coronary angioplasty (PTCA). Desferri-exochelin 772SM (D-EXO), a highly diffusible, lipophilic iron chelator secreted by Mycobacterium tuberculosis, inhibits proliferation of VSMCs in culture. We hypothesized that treatment with D-EXO would inhibit neointima formation in balloon-injured vessels in vivo. Methods and Results- We subjected 24 pigs to overstretch coronary artery injury with standard PTCA balloons and then administered intramural injections of either D-EXO (n=14) or vehicle (n=10) through an Infiltrator catheter. Treatments were randomized, and the investigators were blinded with regard to treatment group until data analysis was completed. One month later, we euthanized the pigs, excised the injured coronary segments, made multiple sections of each segment, and identified the site of maximal neointima formation. An injury score based on the degree of disruption of the internal or external elastic lamina or media was assigned. D-EXO reduced stenosis index (neointima area divided by the area within the internal elastic lamina), adjusted for injury score, by 47%. Neointima thickness was also reduced. Conclusions- D-EXO, injected intramurally, substantially inhibited formation of neointima in a porcine vascular injury model.