Exogenous delta-animolevulinic acid induces the porphyrin biosynthesis in human skin organ cultures with different porphyrin patterns in normal and malignant human tissue

The carboxylation state of porphyrin metabolites causes their hydrophilic or lipophilic properties and subsequently their distribution in tissues, cells, and subcellular compartments. The profile of porphyrin metabolites either in normal skin or in malignant skin tumors after administration of (delta) -aminolevulinic acid has been studied in detail, yet. Explant cultures of normal skin and neoplastic tissues, e.g., keratoakanthoma and basal cell carcinoma, were incubated with 1 mM ALA for 36 h. Total porphyrin concentration and percentage of porphyrin metabolites were determined quantitatively in tissues and corresponding supernatants. Seventy - ninety percent of total porphyrins could be detected in the supernatants of all samples. The highly carboxylated porphyrins were the prevailing metabolites in the supernatants as well as in the tissues. The basal cell carcinoma produced significantly more protoporphyrin and the keratoakanthoma significantly more coproporphyrin as compared to normal skin. The results show that explant cultures offer an easy approach to examine the enzymatic capacity in porphyrin biosynthesis of various tissues. Benign and malignant human tissues produce different porphyrin metabolites, which may be useful for selective and more effective photodynamic diagnosis or therapy.