US researchers identified two naturally occurring molecules, agmatine and thiamine (vitamin B1), which may serve as biomarkers and therapeutic targets in primary open-angle glaucoma (POAG). 

Writing in Investigative Ophthalmology & Visual Science the University of Missouri team analysed aqueous humour from 29 adult cataract or glaucoma surgery candidates, of whom 19 were POAG patients and 10 were healthy controls. Patients’ mean age was 70.8 years, and 17 were female. Researchers found significantly reduced levels of agmatine and thiamine (vitamin B1) in eyes with POAG.  

Overall, researchers quantified 135 metabolites, identifying agmatine and thiamine as the strongest discriminators between glaucoma and non-glaucoma samples, with depleted levels correlating with inflammatory pathway activation. In a complementary mouse model, supplementing either molecule reduced neuroinflammatory signalling and preserved retinal ganglion cell (RGC) counts, the primary endpoint, compared with untreated controls, they said. 

 “[These metabolites] could be potential immunomodulatory or neuroprotective drugs to treat or prevent neuroinflammatory damage to the retina during glaucoma,” said authors. Their future studies will focus on creating RGC-specific extracellular vesicles by labelling them with RGC-specific antibodies and testing the anti-neuroinflammatory and neuroprotective properties of agmatine and thiamine in glaucoma.