A molecule is effective against the second most frequent blindness
A protein from the immune system fights macular degeneration associated with age
The administration does not require intraocular injections on which the current therapy is based
The therapy has not yet been subjected to clinical trials
What if an ordinary intravenous treatment is enough to fight at the root the main cause of blindness in people older than 60 years after the one caused by diabetes? Small doses of a protein of the immune system (interleukin IL-18) have been shown to be effective against age-related macular degeneration (AMD) in its most aggressive variant, the so-called wet, responsible for 90% of cases of blindness caused by the disease, according to researchers from Trinity College Dublin published in the journal Science Translational Medicine.
If these results are verified in subsequent clinical trials - for the time being, only the effectiveness of the therapy in preclinical models has been proven - the treatment of the disease would be reversed, since the current strategies are limited to the most advanced stages of the disease and require of annoying intraocular injections.
"If these results are confirmed, it could even be used preventatively in at-risk patients, such as people with a history or severe myopic," says Rafael Martínez-Costa, head of the retina unit at La Fe hospital in Valencia.
Macular degeneration is a degenerative disease that usually begins to manifest from the age of 60. The macula is located in the central part of the retina, which is the tissue located in the inner part of the eye.
The light enters through the pupil, is reflected in the retina in the form of an inverted image and on this surface it is transformed into electrical impulses that the optic nerve sends to the brain.
The macula is a central part of this process: it ensures that the vision is clearer. Wet macular degeneration is due to the development of very fragile blood vessels and abnormally low blood vessels to the macula.
When they break, they let blood and liquids escape. As a result, the central vision is greatly affected, to the point of becoming a black dot that grows over time and only respects peripheral vision.
This variant of the pathology (the wet one) appears only in 10% of the cases, but it is the most aggressive, since it causes 90% of the blindness associated with the disease. The current treatment is very aggressive, since it consists of direct injection into the vitreous (the gelatinous part inside the eye) of antiangiogenic substances that slow down the growth of blood vessels.
Perhaps there is a simpler, more efficient and more convenient way to prevent this uncontrolled growth of veins. This is what the Irish researchers expect with intravenous (non-ocular)
administration of IL-18, a protein that produces the immune system linked, among other aspects, to inflammatory processes. Researchers describe this molecule as a watchdog of vision by slowing the development of the harmful blood vessels that grow behind the macula.
"At first we were concerned that IL-18 damaged retinal cells due to its relationship with the inflammatory processes, but surprisingly we saw that administered at low doses had no adverse effects on the retina and suppressed the abnormal growth of vessels blood, "says Sarah Doyle, professor of Immunology at Trinity College in Dublin and first signatory of the work.
While the intraocular injections that have been used for a decade attack the vascular endothelial growth factor (the signal that orders the uncontrolled growth of blood vessels), the IL-18 cytokines go a step further and manage to inhibit the production of VEGF. That is to say, they would attack the problem at the root.
"Of course, it's a step closer to what we do now, but we have to check that it works," adds Martínez Costa.
