Evaluating Metabolic Changes Induced by PhotoBioModulation (PBM) Through Spectrally Resolved Autofluorescence in Dry Age-Related Macular Degeneration (dAMD) Patients

The best treatment to prevent the evolution of early and intermediate forms of dAMD to atrophic degeneration is PhotoBioModulation (PBM). It is based on the principle that molecules can absorb light even if it is not part of specialized light-receiving organs. Irradiation of cells at certain wavelengths can be used to activate native molecules to modulate biochemical reactions and, consequently, whole cellular metabolism. One of the main targets of PBM is mitochondrial activity. Mitochondria are sensitive to irradiation with red-NIR light. PBM might also function by increasing the bioavailability of nitric oxide (NO) by prompting its release from intracellular stores. It is proposed that PBM causes the photodissociation NO from CCO15. NO is known to inhibit electron transport, so dissociation of NO can increase the mitochondrial membrane potential, increase O2, consumption, and thus the proton gradient, ultimately leading to an increase in ATP production. NO can also diffuse outside and act as a messenger capable of causing vasodilation and other effects.

PBM demonstrated a beneficial role in dAMD, characterized by mitochondrial dysfunction, oxidative stress, and inflammation. SrAF allows to assess of mitochondrial function, a target of PBM, as it allows the observation of minor fluorophores such as FAD. The SrAF is used to evaluate the effectiveness of the treatment.