Vice Chair of the Board of Regents, Jack L. Fortner | The University of New Mexico
Vice Chair of the Board of Regents, Jack L. Fortner | The University of New Mexico
Researchers at the University of New Mexico have discovered bacteria in healthy fish brains, potentially impacting future Alzheimer's research. Professor Irene Salinas, who studies vertebrate mucosal immune systems, led the study with her team, focusing on neuroimmunology and host-microbiota interactions.
In 2019, Ph.D. student Amir Mani joined Salinas' team to explore bacterial effects on the brain. They found that healthy fish have bacteria in their blood and organs, leading them to hypothesize that bacteria might also exist in healthy fish brains. "Our original hypothesis was that we may find some bacteria in the part of the brain called the olfactory bulb," said Salinas. However, they unexpectedly found lower bacterial loads there compared to other brain regions.
Their study, published in Science Advances, revealed a living bacterial community in salmonid brains at levels similar to those in the spleen but much lower than in the gut. Over half of this diversity is attributed to gut and blood bacterial communities. The team used fluorescence microscopy to visualize bacteria crossing the blood-brain barrier.
Culturomics helped Mani isolate over 50 identical bacterial strains from trout brains. "We put a lot of effort into optimizing this to work for the blood and low microbial tissues," said Mani.
The researchers sampled various salmonid species worldwide, finding brain bacteria consistently across different environments. Despite these findings, it's unclear if such microbiomes exist in other vertebrates or humans.
"Many others have tried to make the claim that diseased human brains have bacteria," noted Mani regarding Alzheimer's research controversies due to potential contamination issues during sample collection.
This study suggests natural bacterial presence in fish brains without harm could provide insights into brain-bacteria interactions relevant for human health and diseases like Alzheimer's. "I think there are a lot of applications for human health," added Salinas.
The team seeks further funding and collaboration opportunities for continued exploration of brain microbiomes.
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