Part of the book: Skin Cancers
Part of the book: Advanced Aspects of Spectroscopy
Part of the book: Highlights in Skin Cancer
Background: Topical photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA) and methyl aminolevulinate (MAL) as precursors of protoporphyrin IX (PPIX) have been used in skin cancer treatment and other skin diseases. To establish new topical PDT, protocols are necessary first to conduct studies in vivo using animal skin models. The goal of this study is to evaluate the robust correlation between porcine and human skin models in vivo by optical methods to confirm the suitability of porcine skin models to predict drug behavior in the human skin on topical PDT protocols. Methods: The study was performed in vivo using porcine and human skin models. In human skin, ALA and MAL cream mixture samples were applied to the inner arm in a circular area of 1 cm2. In porcine skin, the cream was applied on the back in an area of 4 cm2, over which an occlusive dressing was placed. PPIX production was monitored for up to 5 h using widefield fluorescence imaging and fluorescence spectroscopy techniques. Results: Human skin models showed similar behavior to porcine skin models, which indicates high similarity between both models and confirms that porcine skin is an adequate model to establish new clinical PDT protocols in human volunteers.
Part of the book: Human Skin Cancers
The illumination system composed of LEDs is an anatomically adjustable device of high intensity that can be applied in different areas of the body. It can be applied in health care, as in the dermatological and esthetic treatments. The device improved the treatment of pathological diseases (e.g. actinic keratosis) since disseminated lesions were reached in a single application, thus reducing the time of the procedure and ensuring homogeneous light distribution. It was compared with a smaller and non-adjustable illumination device and evaluated in the treatment of actinic keratosis. The results showed its versatile application and a uniform adjustment to body curvatures.
Part of the book: Photodynamic Therapy
Antimicrobial resistance (AMR) and its relevant health consequences have been explicitly framed as a shared global problem and are estimated to be one of the largest causes of death worldwide by 2050. Antimicrobial photodynamic therapy (aPDT) proposes an alternative treatment for localized infections in response to AMR’s ever-growing problem. This technique combines molecular oxygen, a non-toxic photoactivatable photosensitizer (PS), and light of appropriate wavelength, leading to the formation of cytotoxic reactive oxygen species. Besides the ability to inactivate resistant pathogens via a non-selective approach (multiple targets), a relevant advantage of aPDT resides in the fact that no evidence of microorganism resistance has ever been reported to it. In this chapter, we address some efforts to use this technology to kill bacteria in the respiratory tract, from in vitro to clinical applications. We put forward three focuses: pharyngotonsillitis, pneumonia, and preventing secondary infections during the use of a photosensitizer-functionalized endotracheal tube. The results here presented offer a foundation for what may become a much larger clinical approach to treat respiratory tract infections.
Part of the book: Photodynamic Therapy