Experiments on mice have shown that delivering neuroprotective drugs to the brain using a nasal aerosol spray may help prevent the death of brain cells after stroke.
UT Health Science Center San Antonio researchers point out that current treatments for stroke include clot-busting drugs and surgery that must be administered within a few hours of the beginning of symptoms.
They say that aerosol can be effective in crucial hours before the actual treatment begins.
After three hours, surgery is often necessary to bust the clot or retrieve it, and after six hours, it is difficult to limit stroke damage by any means.
The researchers claim that aerosol drug delivery through the olfactory nerve can potentially expand that window.
The drugs are delivered via the olfactory nerve, which controls the sense of smell.
In humans, connections from this nerve extend to areas controlling speech, comprehension and opposite-side movement, all of which may be damaged by an ischemic stroke resulting in devastating disabilities. Ischemia is a lack of oxygen resulting from clots blocking blood vessels.
"This nerve is a highway to the brain through which we can easily deliver brain tissue-preserving agents, and we think this method of delivery may be good for eight to nine hours after a stroke begins," said David F. Jimenez, M.D., professor and chairman of the Department of Neurosurgery at the Health Science Centre.
During the study, the method has proven effective in a mouse model of stroke.
"In mice it travels from the nose to crucial brain regions within 20 minutes. It is not affected by the blood-brain barrier, which prevents many drugs that are administered by injection from entering the brain," said Murat Digicaylioglu, M.D., Ph.D., assistant professor and director of neurosurgical research in the Department of Neurosurgery.
In treated mice, the volume of brain tissue killed by stroke is two-thirds less than that of untreated mice, he added.
"Most importantly, we have seen significant improvement in neurological outcome after stroke with this treatment, including motor function and behavioral measures such as ability to navigate a maze," said Digicaylioglu.
If the treatment is approved for use in humans, it is plausible to assume it could be carried aboard ambulances as a frontline therapy for immediate care of stroke patients.