Steinbach, Pia and Wedmgandt, Helmut and Baumgartner, Reinhold and Kriegmair, Martin and Hofstädter, Ferdinand and Knüchel, Ruth (1995) CELLULAR FLUORESCENCE OF THE ENDOGENOUS PHOTOSENSITIZER PROTOPORPHYRIN-IX FOLLOWING EXPOSURE TO 5-AMINOLEVULINIC ACID. PHOTOCHEMISTRY AND PHOTOBIOLOGY, 62 (5). pp. 887-895. ISSN 0031-8655, 1751-1097
Full text not available from this repository.Abstract
Supplying 5-aminolevulinic acid (ALA), a precursor in the biosynthetic pathway to heme from an external source leads to an accumulation of the endogenous fluorescent photosensitizer protoporphyrin IX (PPIX). Following instillation of ALA in the urinary bladder neoplastic tissue can be discerned by fluorescence cystoscopy or treated by illumination with light of an appropriate wavelength. In order to provide a biological rationale for the clinical findings, we have analyzed the capacity of three different cell lines to accumulate PPM by flow cytometry. Three different urothelial cell Lines, normal fibroblasts and endothelial cells were exposed to ALA under varying conditions. Urothelial cell lines J82 and RT4, derived from malignancies of the bladder displayed fluorescence intensities 9- and 16-fold, respectively, above the fluorescence level of the normal urothelial cell line HCV29. Human umbilical cord endothelial cells fluoresced moderately while the fibroblast cell line N1 exhibited a fluorescence level comparable to those of the cancer cells. Fluoresence increased with increasing cell density and was also dependent on the growth of cells as monolayers or multicellular spheroids. Increasing ALA concentrations led to saturation of fluorescence after 4 h of incubation at cell type-specific fluorescence levels obtained at different ALA concentrations. Continuous incubation in medium containing serum resulted in a linear rise of fluorescence during the first 4 h, which was followed by a saturation period (8-24 h) and a renewed rise. In the case of serum depletion, fluorescence intensities were significantly higher and increased linearly during the entire 48 h incubation period. By replacing serum with albumin, it could be shown that the emission of PPM into the medium in the presence of serum is mainly caused by this protein. The ALA-induced fluorescence was predominantly perinuclear after 4 h of incubation and relocated toward the cell membrane after prolonged incubation. This study demonstrated the complexity of factors influencing the ALA-induced fluorescence and should stimulate further research in this field.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PHOTODYNAMIC THERAPY; SUBCELLULAR-LOCALIZATION; PORPHYRIN ACCUMULATION; LEUKEMIC-CELLS; TUMOR-CELLS; ALA |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Pathologie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 02 Jan 2024 09:39 |
| Last Modified: | 02 Jan 2024 09:39 |
| URI: | https://pred.uni-regensburg.de/id/eprint/52247 |
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