HEMATOPORPHYRIN DERIVATIVE UPTAKE BY ATHEROMA IN ATHEROSCLEROTIC RABBITS: THE SPECTRA OF FLUORESCENCE FROM HEMATOPORPHYRIN DERIVATIVE DEMONSTRATED BY AN EXCIMER DYE LASER

Abstract A new diagnostic and therapeutic endoscopic system consisting of an excimer pulse dye laser is presented. This report demonstrates the accumulation of hematoporphyrin derivative (HpD) in atheroma as shown by the fluorescence of HpD using this equipment. Atheroma was induced in the aorta of WHHL (Watanabe heritable hyperlipidemic) rabbits, 5 mg kg^?1 HpD was injected intravenously and the rabbits were sacrificed 24 h later. The aorta was dissected and the localization of HpD was examined. Characteristic peaks of the fluorescence of HpD at 630, 665 and 690 nm wavelength were detected in the atheromatous lesion. However, in the fatty plaque, the emission peak at 630 nm was lower and the 665 nm peak faded away. No fluorescence with peaks was detected in the normal area. The ratio of fluorescence intensity in atheroma, border zones and normal areas was 10.4 : 5.0 : 1.0. On normal rabbits made atherosclerotic by diet and balloon damage, an ultra thin endoscopic catheter was inserted from the descending aorta of atherosclerotic rabbits under anesthesia. Essentially the same data was obtained by these studies in vivo as was obtained in the in vitro studies. The above data suggests the possibility of future applications of this equipment for diagnosis of atheroma.