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Preferential Relative Porphyrin Enrichment in Solar Keratoses upon Topical Application of ^‐Aminolevulinic Acid Methylester
Author(s) -
Fritsch Clemens,
Homey Bernhard,
Stahl Wilhelm,
Lehmann Percy,
Ruzicka Thomas,
Sies Helmut
Publication year - 1998
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1998.tb02492.x
Subject(s) - porphyrin , photodynamic therapy , chemistry , protoporphyrin ix , actinic keratoses , protoporphyrin , dermatology , chlorophyllin , photochemistry , chlorophyll , medicine , organic chemistry
Topically applied δ‐aminolevulinic acid is used efficiently for the treatment of solar keratoses by photodynamic therapy. Recent animal studies suggest that porphyrin sensitization of epithelial tissue is improved by using esters rather than free δ‐aminolevulinic acid. The present study examines porphyrin metabolite formation after topical application of δ‐aminolevulinic acid or δ‐aminolevulinic acid methylester in human solar keratoses versus adjacent normal skin. Levels of total porphyrins, porphyrin metabolites and protein were measured in skin samples excised after 1 and 6 h. Higher levels of porphyrins were observed in solar keratoses than in normal skin with both substances. Maximum porphyrin levels were present in solar keratoses treated with δ‐aminolevulinic acid for 6 h. However, the ratio of porphyrins in solar keratoses versus adjacent normal skin was higher with 8‐aminolevulinic acid methylester. The pattern of porphyrins showed no significant difference between normal and afflicted skin, protoporphyrin being predominant. The results suggest that application of free δ‐aminolevulinic acid may be more effective in sensitizing solar keratoses. However, treatment with 8‐aminolevulinic acid methylester leads to a preferential enrichment of porphyrins within lesional skin.