Photodynamic effects on rabbit auricular veins after photosensitization with porfimer sodium: Implications of the results with respect to the treatment of esophageal varices with photodynamic therapy.
BACKGROUND
There are numerous clinical applications for photodynamic therapy in the GI tract. The principal reason for the wide variety of lesions amenable to photodynamic therapy is the ability to treat large areas of mucosa without the need for complete visualization. This report describes observed hemodynamic and histologic changes in rabbit auricles after photodynamic therapy and the feasibility of photodynamic therapy for esophageal varices.


METHODS
Porfimer sodium and an argon-dye laser (630 nm, 300 mW/cm(2)) were used. Twenty rabbits were grouped according to porfimer sodium dose: group 1 (2.0 mg/kg, n = 10); group 2 (1.0 mg/kg, n = 6); group 3 (0.2 mg/kg, n = 4). Rabbit auricular veins were classified according to time duration of laser illumination: V(0), no illumination; V(5), 5 minutes; V(10), 10 minutes; V(15), 15 minutes. Hemodynamic changes were observed with a laser Doppler blood flow meter. Histologic changes were evaluated by light microscopy.


RESULTS
For groups 1 and 2, there was a significant decrease in blood flow for V(15) after photodynamic therapy, but not in group 3. There was a significant difference in the grade of thrombus between V(5) and V(15) in groups 1 and 2, and between V(10) and V(15) in group 2. There was a significant difference in the grade of venous dilation (congestion) for V(15) between groups 1 and 3 (p < 0.05, Kruskal-Wallis test).


CONCLUSIONS
Endoscopic photodynamic therapy could possibly improve the outcome for endoscopic treatment of esophageal varices beyond that achieved by sclerotherapy or band ligation alone.
Nagamine
Nobuhiko
N
Department of Gastroenterology, Jichi Medical School, 3311-1 Yakushiji, Minamikawachi-machi, Kawachi-gun, Tochigi 329-0498, Japan.
Ido
Kenichi
K
Saihuku
Kouji
K
Higashizawa
Toshihiko
T
Ono
Kazunori
K
Hirasawa
Tomosuke
T
Sugano
Kentaro
K
Chong
Ja-Mun
JM
D000818:Animals; D017323:Dihematoporphyrin Ether / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004423:Ear / Q000098:blood supply* / Q000473:pathology; D004932:Esophageal and Gastric Varices / Q000188:drug therapy*; D005240:Feasibility Studies; D006414:Hematoporphyrin Photoradiation; D008297:Male; D011817:Rabbits; D013927:Thrombosis / Q000473:pathology; D014680:Veins
D017323:Dihematoporphyrin Ether