Determining light dose for photodynamic therapy of atherosclerotic lesions in the Yucatan miniswine.
OBJECTIVE
To determine the light dose required for photodynamic therapy of atherosclerotic lesions in the miniswine.


METHODS
Aortic atherosclerosis was created in seven Yucatan miniswine by a combination of balloon endothelial injury and 2% cholesterol and 15% lard for 7 weeks. Six animals received the photosensitizer Photofrin 2.5 mg/kg, while an additional swine received no drug. After 24 hours, the abdominal aorta was exposed and the aorta opened longitudinally in each animal. Three 1-cm spots were illuminated with energy densities of 60, 120, and 240 J/cm2 from an argon-pumped dye laser tuned to 630 nm with a laser output of 1 W. Four weeks later, the animals were killed, abdominal aortae removed, and intimal thickness determined by morphometry.


RESULTS
The percentage intimal thickness (mean +/- SD) was 36.7 +/- 27.1, 9.1 +/- 5.0, and 6.4 +/- 8.1 for the three energy densities, respectively. Although both 120 and 240 J/cm2 energy densities produced significant (p < 0.05) reduction in atheroma, considerable damage to the underlying media was also observed in the 240 J/cm2 group.


CONCLUSIONS
A Photofrin dose of 2.5 mg/kg and 120 J/cm2 light are necessary for adequate ablation of atheroma while avoiding extensive medial damage.
Hsiang
Y N
YN
Department of Surgery, University of British Columbia, Vancouver, Canada.
Todd
M E
ME
Bower
R D
RD
D000818:Animals; D001012:Aorta, Abdominal / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects*; D001161:Arteriosclerosis / Q000188:drug therapy* / Q000473:pathology; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D007262:Infusions, Intravenous; D053685:Laser Therapy; D008297:Male; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D013552:Swine; D013556:Swine, Miniature
D017319:Photosensitizing Agents