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Novel photodynamic therapy against biliary tract carcinoma using mono-L: -aspartyl chlorine e6: basic evaluation for
Kazuhiko Kasuya1, Motohide Shimazu, Minako Suzuki
1Department of Digestive Surgery, Hachioji Medical Center of Tokyo Medical University, 1163 Tatemachi, Hachioji, Tokyo, 193-0998, Japan. kasuya-k@jcom.home.ne.jp
Background:
Recently, a second-generation photosensory agent for photodynamic therapy (PDT), mono-L: -aspartyl chlorine e6 (NPe6), which degrades rapidly in vivo, has been developed. We evaluated its feasibility and efficacy for treatment in biliary tract carcinoma.
Methods:
A transmittance of semiconductor laser light (664 nm), sensitivity of a human biliary tract carcinoma cell line, and disorder to normal tissue including Glissonian constructs and adjacent hepatocytes were investigated.
Results:
The transmittance of the laser was 85-91% through yellow clear bile and that of the bile including 50 microg/ml NPe6 was 17-48%. The effective concentration of NPe6 which showed LD50 for a cell line was 12.5 microg/ml, and that of LD95 was 25 microg/ml. NPe6 in the supernatant reduced laser transmissiveness, but it had little influence on the antitumor effect in supernatant with or without NPe6. The NOZ cell-tumor volume was reduced significantly 14 days after irradiation in the PDT group (PDT 69.9 +/- 44.6 mm(3) vs control 296.3 +/- 239.9 mm(3) P < 0.05). No severe hepatic disorder including Glisson components was observed by the histological findings.
Conclusion:
NPe6 PDT was effective in carcinomas even in the presence of bile, and causes no serious complication for the liver and Glisson structure. Therefore, NPe6 PDT will be a useful candidate as a new therapy for biliary tract carcinomas.
