Japanese researchers at Tokyo University of Science have pioneered a non-invasive nasal spray that addresses key physiological effects of depression, offering a safer alternative to traditional treatments.
Nasal sprays have a proven track record in medical research. In 2020, U.S. scientists developed a SARS-CoV-2 vaccine as a nasal spray, while in 2018, researchers introduced one to combat gambling addiction. Now, a July 2021 study in the Journal of Controlled Release highlights a nasal spray designed to fight depression, delivering relief to physiological symptoms in about twenty minutes.
Conventional treatments rely on intracerebroventricular (ICV) injections, which are highly invasive and carry significant risks due to challenges in delivering molecules directly to the brain. This new spray overcomes those barriers effectively.
Prior studies focused on the olfactory epithelium, which makes up just 2% of the nasal mucosa. Instead, these researchers targeted the more abundant respiratory epithelium. They harnessed the GLP-2 peptide, a key signaling molecule between tissues, engineering the spray to prevent GLP-2 degradation for seamless passage to the brain.
In experiments with mice exhibiting depression-like behaviors akin to humans, the spray produced measurable improvements in physiological signs of depression within about twenty minutes. Note that these changes were behavioral and physiological, not direct alterations to psychological states.
This innovation could pave the way for new treatment avenues in depression and beyond, potentially including Alzheimer's. For context, in 2019, the U.S. FDA was on the verge of approving an esketamine-based nasal spray for depression.
