A Ray of Light Against Age Related Neurodegeneration

Mitochondrial function declines with age and many pathological processes of neurodegenerative diseases stem from this dysfunction when mitochondria fail to produce the necessary energy required. Photobiomodulation (PBM), long-wavelength light therapy, has been shown to rescue mitochondrial function in animal models and improve human health, but clinical uptake is limited due to uncertainty around efficacy and the mechanisms responsible. Through combined theoretical Monte Carlo light modelling and practical 31P Magnetisation Transfer Magnetic Resonance Spectroscopy (MT-MRS) we quantify the effects of 670 nm PBM treatment on healthy aging brains. 31P MT-MRS revealed a significant increase in the rate of ATP flux after PBM in a sample of older adults. Light modelling shows 1% absorption in grey matter and confirms absorption peaks at 670 and 820 nm. Our study provides evidence of PBM therapeutic efficacy and strengthens confidence in PBM as an acceptable healthcare technology to improve mitochondrial function and human health. ### Competing Interest Statement The authors have declared no competing interest. * ADP : adenosine diphosphate ATP : adenosine triphosphate BW : bandwidth Cr : creatine ETC : electron transport chain FWHM : Full width at half maximum Pi : inorganic phosphate MCS : Monte Carlo simulation MRS : magnetic resonance spectroscopy MT : magnetisation transfer PBM : photobiomodulation PCr : phosphocreatine RF : radiofrequency ROS : reactive oxygen species TE : Echo time TR : Repetition time.