Ultrastructural alteration of tape-stripped normal human skin after photodynamic therapy

• Published in: EJD. European journal of dermatology Vol. 14; no. 2; pp. 91 - 95
• Main Authors: BARTOSIK, Jacek, STENDER, Ida-Marie, KOBAYASI, Takasi, AGREN, Magnus S
• Format: Journal Article
• Language: English
• Published: Montrouge Libbey-Eurotext 01-03-2004
• Subjects: 5-aminolevulinic acid; Adult; Aminolevulinic Acid - administration & dosage; apoptosis; Biological and medical sciences; Biopsy - methods; Clinical Medicine; Dermatologi och venereologi; Dermatology; Dermatology and Venereal Diseases; Dermis - drug effects; Dermis - radiation effects; Dermis - ultrastructure; Diseases of the skin. Cosmetics; Female; Humans; keratinocytes; Keratinocytes - drug effects; Keratinocytes - radiation effects; Keratinocytes - ultrastructure; Klinisk medicin; Langerhans cells; Langerhans Cells - drug effects; Langerhans Cells - radiation effects; Langerhans Cells - ultrastructure; Male; Medical and Health Sciences; Medical sciences; Medicin och hälsovetenskap; melanocytes; Melanocytes - drug effects; Melanocytes - radiation effects; Melanocytes - ultrastructure; Photochemotherapy; Photosensitizing Agents - administration & dosage; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Reference Values; Skin - drug effects; Skin - radiation effects; Skin - ultrastructure; ultrastructure; Human; Photodynamic therapy; Treatment; melanocytes; Dermatology; Ultrastructure; Langerhans cells; apoptosis; Skin; keratinocytes; 5-aminolevulinic acid
• ISSN: 1167-1122; 1952-4013

The effect of photodynamic therapy on tape-stripped normal human skin was explored ultrastructurally. Back skin areas of 3 healthy Caucasian volunteers, 2 men and 1 woman, were tape-stripped 10 consecutive times followed by topical treatment with 5-aminolevulinic acid (20%, w/w) for 4 hours under occlusion (Tegaderm). Then the areas were irradiated for 30 minutes with Waldman PDT 1200 lamp (570-650 nm) with a total dose of 70 J/cm(2). Full-thickness punch biopsies were taken immediately after irradiation, and at 3 and 24 hours for electron microscopy examination. Photodynamic therapy caused morphological alterations mainly in the epidermis. Keratinocytes became oedematous and tonofilament bundles were split, but desmosomes remained normal. Many keratinocytes contained large intracellular vacuoles and extremely electronlucent cytoplasm implying cell damage. Although the majority of Langerhans cells were unaffected isolated Langerhans cells became apoptotic at 3 hours. The melanocytes preserved their normal morphology. The epidermal alterations recovered 24 hours after the irradiation. Inflammatory cell infiltrates were evident at 3 and 24 hours but no other dermal changes were observed. In conclusion, photodynamic therapy with 5-aminolevulinic acid affects mainly keratinocytes and can trigger apoptosis in Langerhans cells while melanocytes appear refractory, at least morphologically, to photodynamic therapy.