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5‐aminolevulinic acid (ALA)‐induced protoporphyrin IX fluorescence and photodynamic effects in the rat bladder: An in vivo study comparing oral and intravesical ALA administration
Author(s) -
Chang ShiChung,
Buonaccorsi Gio,
MacRobert Alexander J.,
Bown S. G.
Publication year - 1997
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/(sici)1096-9101(1997)20:3<254::aid-lsm4>3.0.co;2-p
Subject(s) - protoporphyrin ix , urothelium , photodynamic therapy , phototoxicity , medicine , in vivo , urology , oral administration , pathology , protoporphyrin , urinary bladder , chemistry , pharmacology , in vitro , biology , porphyrin , biochemistry , microbiology and biotechnology , organic chemistry , photochemistry
Background and Objective Photodynamic therapy (PDT) using 5‐aminolevulinic acid (ALA)‐induced protoporphyrin IX (PpIX) for sensitization is a promising treatment for carcinoma in situ and diffuse premalignant changes of the bladder. We studied the biodistribution of PpIX in a range of tissues with oral and intravesical routes of administration of ALA and compared the photodynamic effects on bladder and skin. Study Design/Materials and Methods: Normal Wistar rats were given oral or intravesical ALA and PpIX levels in the liver, kidney, skin, and bladder measured by fluorescence microscopy on tissue sections. At the time of maximum PpIX levels, the bladder and skin on the back were illuminated with light at 630 nm and the PDT effects compared. Results PpIX fluorescence in the urothelium after 200 mg/kg given intravesically was comparable to that found after 100 mg/kg orally. The ratio of PpIX levels between the urothelium and the underlying muscle was the same for both routes of administration, although there appeared to be more selectivity of urothelial PDT necrosis after intravesical administration. Skin photosensitization was greater after oral ALA, the epidermal PpIX level being three times higher than after intravesical administration for comparable urothelial levels and the PDT effect being more marked. Conclusions Intravesical instillation is preferable to oral administration of ALA for PDT ablation of the urothelium of the rat bladder without damage to the underlying tissue layers and for minimizing skin photosensitivity. The technique is now ready for clinical trials. Lasers Surg. Medicine 20:254–264, 1997. © 1997 Wiley‐Liss, Inc.