Antimicrobial Photodynamic Therapy for Pneumonia using extra body illumination: a translational approach
Lower respiratory tract infections are the leading infectious cause of death worldwide. With the emergence of new viral respiratory pandemics, as seen currently with COVID-19, and the antibiotic-based therapy crisis due to the increase in resistance and a lack of new molecules, comes a desperate need for new treatment approaches that are effective against multiple pathogens and unlikely to select for resistance. Antimicrobial Photodynamic Therapy (aPDT), comes in as a promising alternative for the treatment of these infections, since the induced damage and resultant death are not dependent on a specific molecule or pathway. The applicability of aPDT using the photosensitizer indocyanine green (ICG) and extracorporeal activation with infrared light has been previously demonstrated for different bacterial agents. However, for it to become a clinical treatment, there are four elements that need to be achieved in the translational research: the efficient pulmonary delivery of the photosensitizer; the efficient delivery of light through multiple layers of biological tissue; assured selectivity and safety for the proposed treatment; and the efficacy in killing the pathogens in a large scale and complex microenvironment. This presentation will discuss recent results regarding all four elements, and how they corroborate to the design of a promising new clinical treatment. Key findings include the selectivity of ICG for pathogens over mammalian cells, and the demonstration of a feasible light-activation protocol using an external light source in an in vivo pig model.
University of Sao Paulo
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