Introduction: Although angiotensin II receptor blockers (ARBs) and Statins are known as plaque stabilizers with anti-inflammatory effects, the in vivo evidence is lacking in coronary arteries. In this study, we aimed to in vivo assess the serial effects of ARB/Statin on coronary-sized atheroma using our customized fully integrated optical coherence tomography (OCT)-near-infrared fluorescence (NIRF) structural-molecular imaging.
Methods and Results: Using balloon-injured New Zealand white rabbits, plaque at baseline was assessed by the OCT-NIRF imaging with a FDA approved NIRF emitting indocyanine green (ex/em 805/830 nm) to enhance lipid-rich inflamed plaque. After baseline imaging, rabbits were randomly divided into three groups; olmesartan (1mg/kg/day) vs. rosuvastatin (1mg/kg/day) vs. controls. The medications were given for 4 weeks, followed by serial in vivo imaging of the same plaque segments. NIRF signals of OCT-delineated lipid-rich plaques dramatically decreased in the ARB/Statin treated groups compared to the controls (p < 0.01, both), while less prominent in the ARB group than Statin treated group (Figure). Ex vivo fluorescence reflectance imaging, fluorescence microscopy and immunostainings of the corresponding sections well validated the in vivo findings, showing decreased macrophage and lipid content.
Conclusions: By the integrated OCT-NIRF serial imaging, Statin and ARB showed robust plaque stabilizing effects in coronary-sized vessels via down-regulation of macrophage and lipid accumulation. Our highly translatable imaging strategy capable of evaluating the efficacy of medical intervention could play a pivotal role in personalized therapeutics.