Lights on for Autism: Exploring Photobiomodulation as an Effective Therapeutic Option

Abstract

Autism is a neurodevelopmental condition that starts in childhood and continues into adulthood. The core characteristics include difficulties with social interaction and communication, together with restricted and repetitive behaviours. There are a number of key abnormalities of brain structure and function that trigger these behavioural patterns, including an imbalance of functional connectivity and synaptic transmission, neuronal death, gliosis and inflammation. In addition, autism has been linked to alterations in the gut microbiome. Unfortunately, as it stands, there are few treatment options available for patients. In this mini-review, we consider the effectiveness of a potential new treatment for autism, known as photobiomodulation, the therapeutic use of red to near infrared light on body tissues. This treatment has been shown in a range of pathological conditions-to improve the key changes that characterise autism, including the functional connectivity and survival patterns of neurones, the patterns of gliosis and inflammation and the composition of the microbiome. We highlight the idea that photobiomodulation may form an ideal treatment option for autism, one that is certainly worthy of further investigation.

Keywords: cell death; infrared; mitochondria; non-pharmacological; red.

Figure 1

Schematic diagrams of the major abnormalities evident in autism (A; left side) as compared to normal, and after photobiomodulation treatment (B; right side). Autism is characterised by an altered microbiome in the gastrointestinal system (red star-like shapes), decrease in size of cerebellum and cerebellar cell number, increase in brain-derived neurotrophic factor (BDNF) levels in brain (yellow shade) and blood plasma, gliosis and inflammation in brain (pink cells), macrocephaly (increase in size of cortex), decrease in activity of long-range connectivity in cortex (thin red arrows), synaptic imbalance in brain, imbalance of functional connectivity, dysfunction and oxidative stress in brain (red cells) and increase in local interconnectivity in cortex (thick red arrows). We hypothesise that many if not all of these abnormalities will improve after photobiomodulation treatment to the head and to the abdomen (green cells and arrows). In particular, photobiomodulation will prompt; an increase in mitochondrial function, adenosine triphosphate (ATP) levels and gene expression, a reduction of oxidative stress, inflammation and gliosis, a restoration of cell homeostasis and growth factor levels, together with a restoration of a balanced functional activity across the brain.