Junichi Hayashi

Change in chemical composition of lipids accumulated in atheromas of rabbits following photodynamic therapy.

Mono‐L‐aspartyl chlorin e6 (NPe6) has been used in the photodynamic therapy of neoplasms. This substance has been shown to accumulate in atheroma of rabbits. We evaluated the change in the lipid components of atheromas after photodynamic therapy with NPe6 using Fourier transform infrared (FTIR) microspectroscopy.

Long-term pioglitazone therapy improves arterial stiffness in patients with type 2 diabetes mellitus.

Pioglitazone, a peroxisome proliferator-activated receptor gamma agonist, not only improves insulin resistance and glycemic control, but may also have additional beneficial vascular effects in patients with type 2 diabetes mellitus. We investigated whether pioglitazone had an influence on arterial stiffness, which is an independent predictor of cardiovascular events, in 204 patients with type 2 diabetes mellitus. A prospective, nonrandomized, open-label trial was performed that involved 41 patients treated with pioglitazone, 46 patients receiving sulfonylureas, 67 patients on insulin, and 50 patients on diet/exercise only. The follow-up period was 56 +/- 3 months. Arterial stiffness was evaluated by using the arterial stiffness index (ASI), which was based on analysis of the pulse wave amplitude pattern obtained during automated blood pressure measurement in the upper limb. The 4 groups had a similar baseline ASI, which was greater than the reference range in each group. Although antidiabetic therapies improved hemoglobin A(1c) and low-density lipoprotein cholesterol, ASI only decreased significantly in the pioglitazone group. Thus, pioglitazone improved abnormal arterial stiffness in patients with type 2 diabetes mellitus via a mechanism beyond the metabolic improvement. These findings may have important clinical implications in the use of pioglitazone in patients with type 2 diabetes mellitus.

Long-term inhibition of intimal hyperplasia using vascular photodynamic therapy in balloon-injured carotid arteries

Flexible treatments for intimal hyperplasia after angioplasty are still needed. The aim of this study was to demonstrate the long-term effects of vascular photodynamic therapy with talaporfin sodium on intimal hyperplasia following interventional injury. Intimal hyperplasia was induced by balloon distension injury to the carotid artery in 31 rabbits. Talaporfin, 5.0 mg/kg, was delivered systemically immediately after balloon injury. The injury site was irradiated with a diode laser light of wavelength 664 nm using a fluence of 50 J/cm2 after 30 min. At day 3 and weeks 3, 6, 9, 15, and 25 after photodynamic therapy, the treated artery of each rabbit was excised and examined immunohistochemically. Thirty minutes after talaporfin administration, drug fluorescence was found only in the balloon-injured carotid artery wall. At 3 days, no smooth muscle cells were seen in the media of the photodynamic therapy-treated arterial segments. Intimal hyperplasia developed progressively in the balloon-injured and untreated segments; however, in the segments treated with photodynamic therapy, intimal hyperplasia was markedly suppressed until 25 weeks and the media was repopulated by smooth muscle cells without macrophages. Vascular photodynamic therapy with talaporfin may be used to inhibit restenosis after vascular intervention.

Acute Effects of Photodynamic Treatment on Elastic Fibre Network in Atherosclerotic Plaques of Rabbit Aorta

Abstract. Our objective was to demonstrate the acute effects of photodynamic treatment on the elastic framework in the atherosclerotic plaque. The photosensitiser, mono-l-aspartyl chlorin 56 (NP56), was administered intravenously, at a dose of 5 mg/kg of body weight, to cholesterol-fed, atherosclerotic rabbits. Six hours later, visible atherosclerotic lesions of the abdominal aorta were irradiated with a diode laser, wavelength 664 nm. The energy administered ranged from 50 J/cm2 to 200 J/cm2. The abdominal aorta was then excised and digested by a modified hot alkaline method. Scanning electron microscopy revealed the destruction of the architecture of the elastic fibre network in the atherosclerotic plaque, whereas no change was seen in the non-atheromatous aortic wall. Damage to the elastic fibre network was more obvious in plaque that was exposed to higher energy levels. No significant changes were observed in laser-treated plaques in animals that did not receive the NP56 pretreatment. Findings suggest that atherosclerotic plaques of the abdominal aorta can be selectively degraded by laser irradiation following pretreatment with the photosensitiser, NP56.

Photodynamic treatment for atherosclerotic plaques of the rabbit abdominal aorta by the laparoscopical approach using a pheophorbide derivative

A new photosensitizer, PH-1126, was administered intravenously into the ear veins of cholesterol-fed atherosclerotic rabbits at a dose of 1 mg/kg of body weight. At 24 hr after PH-1126 administration, the atherosclerotic abdominal aorta was irradiated with a krypton ion laser with a wavelength of 647 nm by 100 J/cm2 by the laparoscopical approach. Twenty-four hours later, the abdominal aorta irradiated by the laser beam was excised for histological analysis. In the atherosclerotic plaques with photodynamic treatment, damaged foam cells were observed by scanning electron microscopy and transmission electron microscopy. Some of these cells were exposed to the aortic lumen. No significant changes were shown in the abdominal aorta either with plaques not injected with PH-1126 or without plaques after photodynamic treatment. These findings suggest that atherosclerotic plaques of the abdominal aorta could be selectively degraded by laparoscopical photodynamic treatment.

Sesame Lignans and Vitamin E Supplementation Improve Subjective Statuses and Anti-Oxidative Capacity in Healthy Humans With Feelings of Daily Fatigue

Sesamin has anti-oxidative functions in vivo. Fatigue is caused in part by oxidative stress. We evaluated whether sesame lignans (sesamin/episesamin = 1/1, 10 mg) with vitamin E (55 mg of α-tocopherol) (SVE) could improve subjective statuses and anti-oxidative capacity in humans using questionnaires on fatigue, sleep and physical appearance, as well as low-density lipoprotein oxidation lag time. A placebo-controlled, double-blind, parallel-group study was conducted with subjects experiencing daily fatigue. After a run-in period, subjects were administered oral SVE or a placebo (P) for 8 weeks. A questionnaire regarding fatigue, sleep and physical appearance was conducted at 0, 4, and 8 weeks. Plasma low-density lipoprotein oxidation lag time was measured as an indicator of anti-oxidative capacity. The per-protocol analysis revealed significant improvements in fatigue status at 4 and 8 weeks compared to 0 weeks in both groups (p < 0.01), and sleep and physical appearance at 8 weeks compared to 0 weeks only in the SVE group (p < 0.01). There were no significant differences observed between the groups. According to the 72-subject subgroup analysis (aged 40 and over), the sleep and physical appearance significantly improved compared to the P group (p < 0.05), and fatigue status showed a tendency for improvement compared to the P group. Anti-oxidative capacity in the SVE group significantly increased compared to the P group (p < 0.01). No adverse events relating to SVE supplementation were confirmed. These results suggest SVE supplementation could safely alleviate daily fatigue and oxidative stress.

Negative Associations Between Arterial Stiffness Parameter Evaluated by Cardio-Ankle Vascular Index and Serum Low-Density Lipoprotein Cholesterol Concentration in Early-Stage Atherosclerosis

The cardio-ankle vascular index (CAVI), calculated values from cardio-ankle pulse wave velocity and blood pressure, corresponds predominantly to the stiffness of the aorta and peripheral arteries of the lower limbs. However, the reported associations between CAVI and serum low-density lipoprotein cholesterol (LDL-C) levels remain inconsistent. A cross-sectional study of 1878 consecutive patients (mean age: 59.2 years) who underwent general health checkup showed a negative association between CAVI and serum LDL-C or non–high-density lipoprotein cholesterol (non-HDL-C) concentrations with age-adjusted correlation and multiple regression analysis. Using the similar analyses divided by the status of risk factors and degree of maximum carotid intima–media thickness (maxIMT), negative correlations between CAVI and LDL-C or non-HDL-C levels were observed only in nonrisk groups including nondiabetics patients or patients with maxIMT <1.0 mm, in those with expected low extent of advanced atherosclerotic lesions. In contrast, such a correlation was not found in each comparable risk-loaded group.

Basic research in PDT

Several photosensitisers are known to accumulate selectively in atheromas, regardless of the size of the involved artery. The new photosensitizer, mono-L-aspartyl chlorin e6 (NPe6), specifically accumulates in the atheroma. In the presence of NPe6, the atheroma could be recognized by detecting the specific fluorescence spectrum of NPe6 using a spectrophotometer. We developed a spectrum analysis system and reported that the fluorescence spectra of NPe6 emitted from atherosclerotic plaques on the descending thoracic aorta were recognized by this analysis system with an angioscopic approach in the animal model of atherosclerosis. We also detected the fluorescence spectrum peak at 675 nm of NPe6 laparoscopically only in parts of the abdominal aorta with an atheroma. This spectrum analysis system is useful to recognize the atheroma, but not to recognize the atherosclerotic lesions of the artery as a whole. So, we developed a fluorescence endoscope. Using the endoscopic analysis system, atheromas on the carotid artery were visualized as reddish spots from inside and outside the artery. Then we developed an epifluorescence stereoscope system, and using this device we visualized small coronary atherosclerosis specifically at the beating heart surface. We extensively examined the effects of photodynamic therapy with NPe6 on the atheroma. We studied the change in the lipid components of the atheroma using Fourier transform infrared (FTIR) microspectroscopy. FTIR microspectroscopic analysis showed a dissociation of ester bonds of cholesterol esters in the atheroma after photodynamic therapy. The framework of the atheroma and the lipids accumulated in the atheroma were destroyed. We also evaluated the change in the elastic framework in the atheroma using scanning electron microscopy. The destruction of the architecture of the elastic fiber network in the atheroma was revealed.

Percutaneous transluminal photodynamic therapy of atheroma using mono-L-aspartyl chlorin e6

Structural changes after photodynamic therapy of atherosclerotic lesions of the thoracic aorta were analyzed by scanning electron microscopy. Cholesterol fed atherosclerotic rabbits were injected intravenously with 5 mg/kg of NPe6. At 6 hours after NPe6 loading, a diode laser irradiated angioscopically on the surface of atheroma with the total energy of 200 mJ/cm2. Scanning electron microscopy showed degeneration of atherosclerotic plaques of the thoracic aorta examined at one week after photodynamic therapy. NPe6 could be a potent photosensitizer for photodynamic therapy of atheroma.

Photodynamic therapy of the atherosclerotic abdominal aorta by laparoscopical approach using a pheophorbide derivative

A new photosensitizer, PH-1126, was administered intravenously into the ear vein of cholesterol-fed atherosclerotic rabbits at a dose of 1 mg/kg of body weight. At 24 hours after PH-1126 administration, the atherosclerotic lesions of the abdominal aorta were irradiated by krypton ion laser at 647 nm of wavelength with 100 J/cm2. The abdominal aorta irradiated by laser beam was excised for histological analysis using the scanning electron microscopy and transmission electron microscopy. In the atherosclerotic plaque irradiated by krypton ion laser, migratory cells were observed and some of these cells were migrated into the lumen of the vessel. These findings suggested that these migratory cells from atherosclerotic plaque were foam cells destroyed by photodynamic therapy.