高橋 昇¹, 上之原 広司², 佐々木 啓吾¹, 吉本 高志¹

Noboru TAKAHASHI¹, Hiroshi UENOHARA², Keigo SASAKI¹, Takashi YOSHIMOTO¹

¹東北大学脳神経外科, ²国立仙台病院脳神経外科

¹Department of Neurosurgery, Tohoku University School of Medicine, ²Department of Neurosurgery, Sendai National Hospital

キーワード : Atheroma, Doxycycline, Sonodynamic therapy, Sonoluminescence

Context Ultrasound has long been studied for its application to diagnostic devices that are minimally invasive and able to visualize deep lesions. Many recent studies have suggested its potential use in sonodynamic therapy as a therapeutic modality for malignant neoplasms.
Objective To establish a new minimally invasive treatment for atherosclerosis, sonodynamic therapy for carotid stenosis, for example, we used doxycycline (DOXY) as a photosensitizer. DOXY taken into atheromatous plaques has been shown to be stimulated by ultrasound.
Materials and Methods We induced atherosclerotic plaques into the abdominal aortas of rabbits with balloon catheter-rub and 8-week administration of 1% cholesterol-food. Vessels grouped as atheromatous or normal were extracted, and both groups were further divided into two more groups: those that had been immersed in 1.0 mM DOXY and washed with saline and those that had not been immersed in DOXY. These vessels were sonicated at 361 kHz and 1.0 W/cm², and their fluorescence was analyzed.
Results In the group of atheromatous plaques treated with DOXY, the fluorescence spectra showed a peak at 510 nm, which is specific to DOXY. The other three groups (atheromatous plaques not treated with DOXY, normal vessels treated with DOXY, and normal vessels not treated with DOXY) showed only a gentle spectral peak at around 445 nm.
Conclusions DOXY accumulates selectively in atheromatous tissue and is stimulated by ultrasound in atheromatous plaque.