The treated animals had significantly better cognition.
- Applying near-infrared light to the brains of mice caused the clearance of harmful metabolites.
- This led to reductions in oxidative stress and improvements on cognitive tests.
- Similar approaches have been previously used in human beings.
Researchers have discovered that infrared lasers promote the clearance of toxic metabolites from the brains of age-accelerated mice by improving lymphatic drainage.
Gunking up the works
Advanced glycation end-products (AGEs), like their acronym suggests, accumulate with age. These substances, which are formed when sugars bind to other molecules without the assistance of enzymes, drive multiple aspects of aging and can lead to metabolic diseases [1]. Introducing AGEs into the brain increases oxidation and leads to amyloid formation [2], and inhibiting the effects of AGEs is a potential treatment method [3].
Previous work has found that many other potentially hazardous, naturally produced substances, including amyloids, are drained by meningeal lymphatic vessels (MLVs) [4]. With aging, MLVs lose their youthful structure, becoming less able to carry away such wastes [5]. The only chemical method that has been found to expand MLVs, however, is vascular endothelial growth factor C, which must be injected directly into the brain in order to work [6].
As the meninges are on the brain’s surface, other treatment methods, such as near-infrared light, are feasible. Previous work has discovered that such phototherapy has beneficial effects in Alzheimer’s model mice [7], and improving MLV drainage also helps to heal brain injury in mice [8]. However, such previous work did not target AGEs, which are the focus of this study.