Exploring the effect of red and near-infrared light on neurodegenerative disease: A focus on amyotrophic lateral sclerosis, Charcot's devastating disease of the motor system.

All neurodegenerative diseases, from Alzheimer's disease to amyotrophic lateral sclerosis (ALS), are characterised by a relentless and progressive degeneration of neurones. The degenerating neurones suffer from mitochondrial dysfunction, glutamate excitotoxicity, metabolic disorder and atypical protein aggregations; there is also widespread neuroinflammation and damage to the neurovascular unit across the nervous system. Unfortunately, there is no current treatment option that addresses all, if not many, of these striking abnormalities, one that stops or even slows the progression of the disease (ie neuroprotective). In this chapter, we explore the potential effectiveness of red and near infrared light (R-NIr) on ALS, one of the most devastating of all the neurodegenerative diseases. This condition impacts the motor system, from the cerebral cortex and brainstem to the spinal cord, as well as many skeletal muscles. Individuals suffer greatly and the survival period after onset of the first signs is often very short, averaging just over 2 years, as against 4-8 years in dementia. We outline two main reasons why R-NIr may have positive outcomes in ALS; (1) R-NIr has been shown to be neuroprotective in many other neurodegenerative diseases, improving cell function and survival, and; (2) unlike many other treatments attempted previously, R-NIr addresses many, if not all features of pathology associated with ALS. In summary, we suggest that R-NIr, with its multi-modal effect, could be a valuable treatment option for patients with ALS, particularly if the treatment is started early, before the development of excessive cellular damage.