Researchers have found that rodent eyes and brains appear to have remarkably similar drainage systems that allow them to clean themselves, and there’s reason to believe that this may also be the case for humans.
This kind of upkeep is required to flush waste cells and fluids out of the body, and we know that the brain uses a tiny system of pipes called the lymphatic system, which is comparable to the lymphatic system that removes waste from the rest of the body.
According to recent studies conducted on mice and rats, the optic nerve and retina, two structures at the back of the eyes, borrow some tricks from the glymphatic system. They channel waste products through a network that resembles the brain’s, in the absence of the typical lymphatic vessels.
This kind of upkeep is required to flush waste cells and fluids out of the body, and we know that the brain uses a tiny system of pipes called the lymphatic system, which is comparable to the lymphatic system that removes waste from the rest of the body.
“The internal structures of the eye are contained within a confined space, necessitating tight control of fluid homeostasis, similar to the brain inside the cranial vault,” the researchers write in their paper.
“Our study offers proof of a highly polarized ocular clearance system, which may have consequences for our comprehension of eye health and illness.”
The elimination of the harmful amyloid beta proteins linked to the onset of Alzheimer’s disease is one of the main functions of the brain’s waste disposal system.
The researchers injected fluorescently labeled amyloid beta proteins into the eyes of lab mice to observe precisely how the eye gets rid of similar waste. The tracing that followed demonstrated how these proteins were moving through specific channels in the optic nerve, which is in charge of returning visual information to the brain.
Traces of the labeled proteins were discovered much farther away a few hours after the injection. These traces were likely carried from the eye into the lymph nodes inside the animal’s neck as part of the body’s normal waste removal process. Once more, this corresponds with how the brain communicates with the body as a whole.
The eye’s version of this cleaning system seems to be activated when the iris moves in response to changing light, even though the brain’s glymphatic system activates at night, which is why sleep is so crucial.
Although the new research is based on mice and rats rather than humans, it’s important to remember that these animals do, on a simpler level, have similar ocular setups to ours. Moreover, studies on rats also contributed to the discovery of the glymphatic system in the human brain, increasing the likelihood that this isn’t just a rodent issue.
These findings not only point out some intriguing parallels between the brain’s and eyes’ waste management processes, but they may also shed light on ocular disorders like glaucoma.
The condition may have damage to the eye’s waste clearance system, which allows excess fluid to accumulate, according to the researchers. We should be able to determine for sure and possibly get a hint at more successful treatments with a closer examination of this recently discovered network.
Physician Peter Wostyn, who was not involved in the study, told Abby Olena at The Scientist, “This represents only the starting point for further investigations on the impact of the ocular glymphatic system on the pathogenesis of several ocular diseases.”