title: Photodynamic therapy: Dermatology and ophthalmology as main fields of current applications in clinic.
abstract: Photodynamic therapy (PDT) of skin tumors or pre-cancerous lesions and of age-related macular degeneration combines the administration of porphyrins or porphyrin precursors and illumination with red light at the diseased sites. Photosensitizers absorbing light beyond 630 nm where tissues have the highest transmittance produce singlet oxygen, a highly reactive activated oxygen species and a major cytotoxin. The PDT of age-related macular degeneration is performed with red laser light after i.v. injection of verteporfin (Visudyne) a hydrophobic porphyrin carried by serum lipoproteins whose endocytosis leads to accumulation of the porphyrin in endothelial cells of choroidal neo-vessels. In the PDT of skin cancers, local synthesis of the photosensitizer occurs after topical application of the natural protoporphyrin IX precursor delta-aminolevulinic acid (or its ester forms) on the lesions. In all the cases, the photosensitizers should be rapidly excreted to avoid a long lasting skin photosensitivity.
authors.affiliation: Clínica Universitária de Dermatologia, Hospital de Santa Maria, Lisbon, Portugal. maiasilva@fm.ul.pt
authors.forename: João N
authors.initials: JN
authors.lastname: Silva
authors.forename: Paulo
authors.initials: P
authors.lastname: Filipe
authors.forename: Patrice
authors.initials: P
authors.lastname: Morlière
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Mazière
authors.forename: João P
authors.initials: JP
authors.lastname: Freitas
authors.forename: Manuel Marques
authors.initials: MM
authors.lastname: Gomes
authors.forename: René
authors.initials: R
authors.lastname: Santus
mesh_terms: D015510:Clinical Medicine / Q000379:methods / Q000639:trends*; D003880:Dermatology / Q000379:methods / Q000639:trends*; D005128:Eye Diseases / Q000188:drug therapy*; D005544:Forecasting; D005602:France; D006801:Humans; D009885:Ophthalmology / Q000379:methods / Q000639:trends*; D010778:Photochemotherapy / Q000379:methods / Q000639:trends*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D012871:Skin Diseases / Q000188:drug therapy*
chemical_list: D017319:Photosensitizing Agents