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Proceedings Paper

Clearance of protoporphyrin IX induced by 5-aminolevulinic acid from WiDr human colon carcinoma cells
Author(s): Asta Juzeniene; Miron Kaliszewski; Andrzej Bugaj; Johan Moan
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Paper Abstract

5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) is the most widely practiced form of PDT in dermatology. One of the advantages of ALA-PDT is that undesirable photosensitization lasts only for 24-48 h. In order to optimize ALA-PDT it is necessary to understand the mechanisms controlling intracellular PpIX clearance (efflux and transformation into heme) in order to decrease protoporphyrin IX (PpIX) clearance rates in the early stages of its production. The aim of this study was to investigate the factors controlling the clearance of intracellular PpIX. Fluorescence spectroscopy was used to study PpIX kinetics in WiDr cells initially treated with ALA. The clearance rate of PpIX in WiDr cells was faster after application of a low concentration of ALA (0.1 mM) than after application of high concentration of ALA (1 mM). PpIX was cleared faster from cells which initially were seeded at low densities than cells seeded at higher densities. The presence of the iron chelator deferoxamine reduced the clearance rate of PpIX, while the presence of ferrous sulfate acted oppositely. The decay rate of PpIX in WiDr cells was faster at higher temperature than at lower. The ferrochelatase activity at pH 7.2 was significantly greater than that at pH 6.7. ALA concentration, application time, cell density, temperature, pH, intracellular iron content, intracellular amount and localization of PpIX are factors controlling PpIX clearance.

Paper Details

Date Published: 13 July 2009
PDF: 9 pages
Proc. SPIE 7380, Photodynamic Therapy: Back to the Future, 73802Q (13 July 2009); doi: 10.1117/12.822944
Show Author Affiliations
Asta Juzeniene, Oslo Univ. Hospital (Norway)
Miron Kaliszewski, Oslo Univ. Hospital (Norway)
Military Univ. of Technology (Poland)
Andrzej Bugaj, Oslo Univ. Hospital (Norway)
Johan Moan, Oslo Univ. Hospital (Norway)
Univ. of Oslo (Norway)

Published in SPIE Proceedings Vol. 7380:
Photodynamic Therapy: Back to the Future
David H. Kessel, Editor(s)

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