Research on light therapy in a Sanfilippo mouse model

08 Jul 2024

In a recently published study, researchers in Australia and Europe have explored whether light therapy has therapeutic potential in Sanfilippo. They found light therapy reduced some inflammatory markers in the brain and blood of a Sanfilippo type A mouse model.

Sanfilippo syndrome is caused by an enzyme deficiency that leads to the build-up of toxic molecules in the body. In the brain, this causes inflammation (called neuroinflammation), which may also contribute to behavioural symptoms and neurodegeneration, both hallmarks of the disease.

There are limited therapy options to address the behavioural symptoms and no treatments that can slow neurodegeneration. One potential therapy that has been investigated in adult neurodegenerative disorders such as Alzheimer’s disease and Parkinson’s that have neuroinflammation and difficult behavioural symptoms in common with Sanfilippo, is photobiomodulation (PBM) therapy.

PBM uses red or infrared light to influence functions inside cells. It is thought to act on structures inside cells called mitochondria, commonly known as the powerhouse of cells as they produce much of the cell’s energy. By helping to improve mitochondrial function, and thus overall cellular function, PBM may reduce inflammation and protect neurons. There is some evidence for benefits in adults with dementia, though the findings have been mixed.

The team in this study, led by Associate Professor Paul Austin at the University of Sydney, aimed to assess if PBM therapy can improve disease markers in a mouse model of Sanfilippo type A. They used a PBM device that sat like a helmet on the head of mice. Both younger (3 weeks old) and older (15 weeks old) mice were exposed to light therapy for 10–14 days at two different energy wavelengths.

In this study, results indicate PBM did not reduce the build-up of toxic molecules in the brain and had no effect on behavioural symptoms or some markers of inflammation. However, the higher wavelength of red light reduced the inflammatory state of the microglia, a type of immune cell in the brain that contributes to neuroinflammation in Sanfilippo, to near-normal levels in older mice.

The treatment also reduced some markers of inflammation in the blood of the mice. Treatment with both wavelengths corrected the inflammatory markers in the blood of younger mice, but only PBM therapy at the higher wavelength normalised the levels of one type of immune cell in older mice.

This is the first study that indicates PBM can reduce inflammation in a mouse model of Sanfilippo. The team suggests future studies in mice are needed with a longer treatment period and a different PBM delivery method to see if the therapy can improve behavioural symptoms in the mice.

PBM devices are available and used by adults and it is a relatively simple treatment to deliver, however, further work is needed to confirm if PBM is feasible to deliver to children with Sanfilippo and can provide any benefits. Funders of the study include Cure Sanfilippo Foundation (USA), and Sanfilippo Children’s Foundation who provided seed funding in the earlier stages of the project.