Increased expression of nuclear NF-κB after coronary artery balloon injury can be inhibited by intracoronary beta-irradiation

Purpose: Molecular mechanisms by which balloon angioplasty injury-induced neointimal hyperplasia can be reduced by intravascular brachytherapy are unclear. We investigated the role of nuclear factor-kappaB (NF-κB) in neointimal hyperplasia following intracoronary irradiation. Materials and methods: Fifty-four coronary arteries from 30 pigs were divided into 6 groups: sham control, balloon angioplasty injury alone, β-irradiation at doses of 14 or 20 Gy, and 14 or 20 Gy beta-irradiation immediately followed by balloon injury. Coronary arteries were injured by overstretch balloon angioplasty and then the arteries were irradiated using a Rhenium-188 (188Re) β-emitting solution-filled balloon. Pigs were scarified one day or one week after coronary interventions for molecular detection and six weeks after the procedures for histological examination. Results: Six weeks after coronary interventions, the histological results show that balloon angioplasty injury had induced intimal hyperplasia in coronary artery but the response was significantly reduced by 28% and 60% when the injury was immediately treated by 14 and 20 Gy 188Re β-irradiation, respectively. The expression of arterial NF-κB p65, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) were detected at one day and one week after the procedures. The treatment of balloon injury could significantly induce the NF-κB p65 expression in both gene and protein levels, and such induction could be significantly reduced by 188Re β-irradiation at dose of 20 Gy. However, the similar result on the regulation of gene expression affected by the β-irradiation could not be observed in ICAM-1 and VCAM-1. Conclusion: The inhibitory effect of intracoronary brachytherapy on neointimal formation following overstretch balloon angioplasty could involve inhibition of NF-κB p65.