Calzavara-Pinton P G, Venturini M, Sala R
Department of Dermatology, Azienda Spedali Civili, P.le Spedali Civili 1, 25123 Brescia, Italy.
J Photochem Photobiol B. 2005 Jan 14;78(1):1-6. doi: 10.1016/j.jphotobiol.2004.06.006.
Photodynamic therapy (PDT) is a two-step procedure, involving the topical or systemic administration of a photosensitizer followed by selective illumination of the target lesion with visible light, which triggers the oxidative photodamage and subsequent cell death within the target area. In dermatology, PDT has proven to be a useful treatment for a variety of malignant tumors and selected inflammatory diseases. In addition, PDT of several infective viral or bacterial skin diseases has been investigated. These investigations grew out of the positive findings of studies of another important use of PDT: that of disinfection of blood products. Up to now, little has been published concerning the application of PDT to fungi, probably due to the fact that research funding has been mainly directed towards blood disinfection, and these pathogens show a low risk of transfusion transmission. However, preliminary findings have demonstrated that dermatophytes and yeasts can be effectively sensitized in vitro by administering photosensitizers belonging to four chemical groups: phenothiazine dyes, porphyrins and phthalocyanines, as well as aminolevulinic acid, which, while not a photosensitizer in itself, is effectively metabolized into protoporphyrin IX. Besides efficacy, PDT has shown other benefits. First, the sensitizers used are highly selective, i.e., fungi were killed at combinations of drug and light doses much lower than that needed for a similar effect on keratinocytes. Second, all investigated photosensitizers lack genotoxic and mutagenic activity. Finally, the hazard of selection of drug resistant fungal strains was never reported. This paper intends to provide a comprehensive overview of investigative studies about the effects of PDT on yeasts and dermatophytes, and bring attention to this application of PDT which we believe very important in that skin mycosis is so common and PDT is not only cost-effective, but also has the advantages of being highly selective and avoiding the occurrence of drug resistant strains.
光动力疗法（PDT）是一种两步程序，包括局部或全身给予光敏剂，随后用可见光选择性照射靶病变，这会引发氧化光损伤并导致靶区域内的细胞死亡。在皮肤科，PDT已被证明是治疗多种恶性肿瘤和某些炎症性疾病的有效方法。此外，还对几种感染性病毒或细菌性皮肤病的PDT进行了研究。这些研究源于对PDT另一重要用途（即血液制品消毒）研究的阳性结果。到目前为止，关于PDT在真菌方面的应用报道很少，这可能是因为研究资金主要用于血液消毒，而且这些病原体的输血传播风险较低。然而，初步研究结果表明，通过给予属于四个化学组的光敏剂，皮肤癣菌和酵母菌在体外可被有效致敏：吩噻嗪染料、卟啉和酞菁，以及氨基乙酰丙酸，后者本身虽不是光敏剂，但可有效代谢为原卟啉IX。除了疗效外，PDT还显示出其他优点。首先，所使用的光敏剂具有高度选择性，即真菌在药物和光照剂量组合下被杀死，该剂量远低于对角质形成细胞产生类似效果所需的剂量。其次，所有研究的光敏剂均无遗传毒性和诱变活性。最后，从未有过关于选择耐药真菌菌株风险的报道。本文旨在全面概述关于PDT对酵母菌和皮肤癣菌影响的研究，并提请关注PDT的这一应用，我们认为这非常重要，因为皮肤真菌病非常常见，而PDT不仅具有成本效益，而且具有高度选择性和避免出现耐药菌株的优点。
