ABSTRACT
BACKGROUND: 5-aminolevulinic acid (ALA), is the precursor of heme biosynthesis and used in photodynamic therapy (PDT). When applied exogenously, it is converted to protoporphyrin IX (PpIX) that is an immediate photosensitizer. PpIX is accumulated selectively in various cells including tumor cells. Because most of photosensitizers emit fluorescence of a specific wavelength, it is very important to identify the fluorescence in the tissues and cells targeted for therapy. OBJECTIVE: This study was undertaken to identify the presence of PpIX fluorescence image and localization in various dermatologic diseases with methyl 5-aminolevulinate (MAL), that satisfactorily penetrates cutaneous lipid layers and cell membranes. METHODS: Various skin diseases such as basal cell carcinoma (6), squamous cell carcinoma (4), keratoacanthoma (6), malignant melanoma (3), extramammary Paget's disease (4), verruca (5), psoriasis vulgaris (5), rosacea (2), and acne (5) were included. We applied MAL, ALA ester, ointment to cutaneous lesions and perilesional area for at least 3 hours. After that, we identified the fluorescence image with Wood's lamp (wavelength 320~400 nm) and photographed fluorescence image. Also, we performed skin biopsies of fluorescence site and investigated the PpIX fluorescent location with a fluorescence microscope. In addition, we treated three cultured cell lines (HaCaT cells, human dermal fibroblasts, A431 cells) with MAL and investigated PpIX fluorescence. RESULTS: The PpIX fluorescence images were observed significantly in basal cell carcinoma, squamous cell carcinoma, extramammary Paget's disease, keratoacanthoma, psoriasis, rosacea, and acne. In tissues, PpIX fluorescence was expressed mainly in the pilosebaceous unit, abnormal keratinocytes, tumor cells including basal cell carcinoma, and extramammary Paget's disease. In addition, PpIX was expressed in the cytoplasm of HaCaT cells, human dermal fibroblasts, and A431 cells in vitro. CONCLUSION: In applieation of photodynamic therapy, this study is expected to be helpful in enhancement of therapeutic effectiveness and increase of indications of diseases.
