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Proceedings Paper

Metabolism and photodynamic therapy (PDT) of aminolevulinic acid (ALA)
Author(s): Ruediger Bachor; Ella Dumbravia Reich; Kurt Miller; Richard E. Hautmann
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Paper Abstract

Thus far, in PDT the photosensitizer is administered systemically in its active form. A new concept is the use of endogenous photosensitizers. ALA is a precursor of protoporphyrin IX (PPIX), a potent photosensitizer. The administration of exogenous ALA may induce biosynthesis of an excess of PP IX, that leads to photodestruction upon light exposure. The goal of our study was to examine dark toxicity of ALA, and its phototoxic potential in vitro. Bladder carcinoma cells (Waf) were incubated with ALA for 3.5 h at a concentration of up to 20 mM for examination of dark toxicity. Irradiation was performed with an argon-dye laser emitting light at a wavelength of 630 nm. After irradiation, cells were incubated for two days, fixed, then stained and counted. Dark toxicity of Waf-cells was appreciated after incubation with ALA beginning at a concentration of 15 mM. Therefore, photodynamic treatment was performed at ALA-concentrations of 1, 5 and 10 mM. After incubation with an ALA- concentration of 1 mM and irradiation, there was only a slight decrease in cell survival. After incubation with 5 and 10 mM ALA and irradiation at 48 J/cm2 cell survival was decreased to 11 and 1.4%, respectively.

Paper Details

Date Published: 18 June 1993
PDF: 7 pages
Proc. SPIE 1881, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy II, (18 June 1993); doi: 10.1117/12.146300
Show Author Affiliations
Ruediger Bachor, Univ. Ulm (Germany)
Ella Dumbravia Reich, Univ. Ulm (Germany)
Kurt Miller, Univ. Ulm (Germany)
Richard E. Hautmann, Univ. Ulm (Germany)

Published in SPIE Proceedings Vol. 1881:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy II
Thomas J. Dougherty, Editor(s)

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