Bacteria that have migrated from the intestines to the eyes could be responsible, at least in part, for certain degenerative diseases of the retina that were until now thought to be of entirely genetic origin, shows work carried out by British researchers and Chinese.
This raises the hope that these diseases could one day be treated with antibiotics, although this possibility still remains distant.
“It gives us a bit of another vision where we have to integrate other organs, such as the digestive system, into the equation of this degeneration,” said Przemyslaw Sapieha, who directs the ocular neurovascular diseases research unit at the Center for research at Maisonneuve-Rosemont Hospital. I think the link is plausible. »
We already knew that mutations in the CRB1 gene weaken the protective barrier of the eyes. Researchers at University College London have now found that mutations in this same gene make the intestinal barrier a little more permeable, potentially allowing bacteria to escape.
The authors of the study therefore genetically modified mice to present an abnormal CRB1 gene. Mice that additionally had reduced levels of gut bacteria did not show retinal damage, compared to mice with normal microbiome. The administration of antibiotics has helped reduce damage to their eyes.
Inherited retinal disorders are estimated to affect approximately 5.5 million people worldwide. If the new work represents new hope for them, we are still far from a new treatment, warns Professor Sapieha, who teaches at the faculty of medicine at the University of Montreal and who has held the Canada Research Chair since 2010. in cell biology of the retina.
“Certainly patients and families of patients who are affected don’t get too excited too quickly,” he said.
Intestinal bacteria “possibly” contribute to retinal degeneration, he added, “but there is still a lot of work to be done,” particularly to verify whether bacteria play a “central” role.
“It’s great work that certainly offers a new avenue, but as with any new work, especially work that has been done in mouse models, there are still several validation steps before we can even think about doing a transfer to humans,” he concluded.
The findings of the new study were published by the prestigious medical journal Cell.