Extensive vulval intraepithelial neoplasia treated with a new regime of systemic photodynamic therapy using meta-tetrahydroxychlorin (Foscan®)

Trends and targets in antiviral phototherapy

Photodynamic therapy (PDT) is a well-established treatment option in the treatment of certain cancerous and pre-cancerous lesions. Though best-known for its application in tumor therapy, historically the photodynamic effect was first demonstrated against bacteria at the beginning of the 20^th century. Today, in light of spreading antibiotic resistance and the rise of new infections, this photodynamic inactivation (PDI) of microbes, such as bacteria, fungi, and viruses, is gaining considerable attention. This review focuses on the PDI of viruses as an alternative treatment in antiviral therapy, but also as a means of viral decontamination, covering mainly the literature of the last decade. The PDI of viruses shares the general action mechanism of photodynamic applications: the irradiation of a dye with light and the subsequent generation of reactive oxygen species (ROS) which are the effective phototoxic agents damaging virus targets by reacting with viral nucleic acids, lipids and proteins. Interestingly, a light-independent antiviral activity has also been found for some of these dyes. This review covers the compound classes employed in the PDI of viruses and their various areas of use. In the medical area, currently two fields stand out in which the PDI of viruses has found broader application: the purification of blood products and the treatment of human papilloma virus manifestations. However, the PDI of viruses has also found interest in such diverse areas as water and surface decontamination, and biosafety.

Temoporfin (Foscan®, 5,10,15,20-tetra(m-hydroxyphenyl)chlorin)--a second-generation photosensitizer

This review traces the development and study of the second-generation photosensitizer 5,10,15,20-tetra(m-hydroxyphenyl)chlorin through to its acceptance and clinical use in modern photodynamic (cancer) therapy. The literature has been covered up to early 2011.

Pseudoepitheliomatous hyperplasia treated by photodynamic therapy with variable irradiation dose and concentration of photosensitizer

OBJECTIVE

The aim of this study was to test the effectiveness of photodynamic therapy (PDT) in treating pseudoepitheliomatous hyperplasia (PEH) after skin wounding.

BACKGROUND DATA

PEH is a difficult-to-treat extreme-degree acanthosis characterized by proliferation of the epithelium. Topical PDT offers an effective and non-invasive treatment for intraepithelial neoplasia and inflammatory dermatosis. These disorders and PEH show the same histological features: epidermal hyperplasia. To our knowledge, there have been no clinical trials published about therapeutic responses of PDT for PEH.

MATERIALS AND METHODS

After application of 10-30% methyl aminolaevulinate (MAL) emulsion, each lesion was irradiated with 633-nm red light at a total dose of 113-339 J/cm(2). Therapeutic response was assessed by clinical examination at 3 months.

RESULTS

Only 4 of 16 lesions clinically showed a minimal response. No response was observed in 12 of the 16 lesions, either with different cumulative doses or different concentrations of MAL.

CONCLUSION

PEH after skin wounding responds poorly to the topical MAL-PDT. Besides removal of underlying diseases, surgical excision is still the recommended first option.