Injecting neuropeptide Y into the eyes of mice with glaucoma preserved retinal nerve cells, reduced inflammation, and prevented optic nerve damage through multiple protective pathways.
Preserved inner retinal integrity under high IOPNPY treatment maintained both structure and function of retinal ganglion cells that would otherwise degenerate from elevated eye pressure
What the researchers found
Neuropeptide Y (NPY) treatment preserved both structural and functional integrity of the inner retina in a mouse model of glaucoma with elevated intraocular pressure. NPY mitigated axonal damage and optic nerve degeneration, reduced inflammatory glial cell activation (decreased GFAP and Iba-1 expression), and restored endogenous NPY and receptor levels (NPY-Y1R and NPY-Y4R) that were depleted under high pressure conditions.
Molecular analysis revealed NPY works through MAPK and PI3K/Akt signaling pathways to achieve its protective effects.
Why it matters
Glaucoma is a leading cause of irreversible blindness, and current treatments focus on lowering eye pressure without directly protecting the nerve cells that die. This study shows a natural brain peptide — neuropeptide Y — can directly protect retinal ganglion cells from pressure-induced damage through multiple mechanisms: reducing inflammation, preventing cell death, and restoring healthy signaling. It opens a potential new therapeutic avenue that targets the neurodegeneration itself, not just the pressure.
The numbers in context
36-amino-acid peptide · NPY-Y1R and NPY-Y4R receptors restored · GFAP and Iba-1 reduced · MAPK and PI3K/Akt pathways activated
How the study worked
Mouse glaucoma model using intracameral microbead injections to elevate intraocular pressure, combined with intravitreal injection of NPY peptide. Researchers assessed retinal structure and function, optic nerve integrity, inflammatory markers (GFAP, Iba-1), endogenous NPY and receptor expression, and molecular signaling pathways (MAPK, PI3K/Akt).
Who was studied
Mice with microbead-induced elevated intraocular pressure (glaucoma model)
What this study cannot tell us
This is a mouse model study — results may not directly translate to human glaucoma. Intravitreal injection is invasive and would need practical delivery solutions for clinical use. The study does not report long-term outcomes or whether repeated dosing would be needed. Specific quantitative outcomes (e.g., percentage of ganglion cell preservation) are not detailed in the abstract.
How to read the evidence
Rated moderate because this is a well-designed animal study published in a reputable journal (PNAS Nexus) with clear mechanistic data, but has not yet been tested in humans.
When this study was published
Published in 2024, this is a recent addition to the growing body of evidence for neuropeptide-based neuroprotection in eye disease.
The bigger picture
Current glaucoma treatments focus almost exclusively on lowering intraocular pressure, but many patients continue to lose vision despite controlled pressure. Neuroprotective approaches that directly shield retinal ganglion cells represent the next frontier. NPY's ability to work through multiple mechanisms — anti-inflammatory, anti-apoptotic, and neurotrophic — makes it a particularly promising candidate in a field that desperately needs alternatives.
Questions still open
- Could NPY be delivered to the eye through less invasive methods like eye drops or sustained-release implants?
- Would NPY treatment also benefit patients whose glaucoma progresses despite normal eye pressure (normal-tension glaucoma)?
- How long does the protective effect of a single NPY injection last in the retina?
Common questions
What is neuropeptide Y and where is it normally found?
Could this lead to a new glaucoma treatment?
Read the original research
Neuropeptide Y receptor activation preserves inner retinal integrity through PI3K/Akt signaling in a glaucoma mouse model.
PNAS nexus, 3(8), pgae299
Citation
Palanivel, Viswanthram; Gupta, Vivek; Chitranshi, Nitin; Tietz, Ole; Vander Wall, Roshana; Blades, Reuben; Maha Thananthirige, Kanishka Pushpitha; Salkar, Akanksha; Shen, Chao; Mirzaei, Mehdi; Gupta, Veer; Graham, Stuart L; Basavarajappa, Devaraj. (2024). Neuropeptide Y receptor activation preserves inner retinal integrity through PI3K/Akt signaling in a glaucoma mouse model.. PNAS nexus, 3(8), pgae299. https://doi.org/10.1093/pnasnexus/pgae299