Photodynamic Diagnosis and Treatment for Atherosclerosis by an Endoscopic Approach

摘要

The photosensitizer, mono-L-aspartyl chlorin e6 (NPe6), specifically accumulates in theatheromatous plaque. We detected the fluorescence spectra of NPe6 emitted fromatheromatous plaques on the descending thoracic aorta by an angioscopic approach usingthe animal model of atherosclerosis. We also showed that a fluorescence spectrum peak at675 nm was obtained laparoscopically only in parts of the abdominal aorta with anatheromatous plaque. By a fluorescence endoscope, atheromatous plaques on the carotidartery were recognized as reddish spots from outside the artery. In addition, we visualizedspecifically at the beating heart surface small coronary atherosclerosis using an epifluorescencestereoscope system.We examined the effects of photodynamic treatment with NPe6 on the atheromatousplaque. The change in the elastic framework in the atheromatous plaque after photodynamictreatment was evaluated using scanning electron microscopy. The destruction of thearchitecture of the elastic fiber network in the atheromatous plaque was revealed. We alsostudied the change in the lipid components of the atheromatous plaque using Fouriertransform infrared (FTIR) microspectroscopy. FTIR microspectroscopic analysis showeda dissociation of ester bonds of cholesterol esters in the atheromatous plaque afterphotodynamic treatment. The framework of the atheromatous plaque and the lipidsaccumulated in the plaque could be destroyed following such treatment.