Substance P Blocker Fosaprepitant Prevents UV-Induced Eye Inflammation in Both Eyes | Research

The takeaway

The NK-1R antagonist fosaprepitant blocked UV-induced inflammation and NK-1R expression in exposed mouse eyes AND in unexposed partner eyes, revealing bilateral substance P-mediated inflammatory signaling.

Both eyes protected
Fosaprepitant blocked UV-induced inflammation not only in the exposed eye but also in the unexposed partner eye, revealing bilateral substance P signaling

What the researchers found

Fosaprepitant (NK-1R antagonist) blocked UVR-B-induced NKR-1 expression and pro-inflammatory cytokine/chemokine production in both exposed and unexposed partner eyes in a mouse cataract model.

Why it matters

UV-related eye damage is a global health concern. Discovering that substance P mediates bilateral eye inflammation from unilateral UV exposure — and that it can be blocked — opens new prevention strategies using existing drugs.

The numbers in context

NK-1R reduced in exposed tissues; NK-1R reduced in unexposed lens epithelium; no cytokine changes; days 3 and 7 endpoints

How the study worked

Animal study. UVR-B-induced cataract mouse model. Unilateral UV exposure. Fosaprepitant treatment. NK-1R expression and pro-inflammatory cytokine/chemokine levels measured in both exposed and unexposed eyes.

Who was studied

C57BL mice with unilateral UVR-B eye exposure

What this study cannot tell us

Mouse model only. Fosaprepitant was given systemically, so off-target effects possible. Long-term cataract prevention not assessed. Bilateral mechanism not fully explained.

How to read the evidence

Low-to-moderate evidence: well-designed mouse study with clear bilateral mechanism, but no human data or long-term outcomes.

When this study was published

Published 2021. NK-1R antagonists for ophthalmological conditions are being explored further.

The bigger picture

This study extends substance P's known inflammatory roles to UV-induced eye damage and reveals surprising bilateral signaling. It suggests NK-1R antagonists could have broader ophthalmological applications beyond nausea prevention.

Questions still open

Could fosaprepitant be developed as eye drops to prevent UV-induced cataracts?
What neural pathway mediates the bilateral substance P inflammatory response?
Would chronic NK-1R blockade protect against age-related cataracts in humans?

Common questions

How does UV damage spread to the unexposed eye?

UV exposure to one eye triggers substance P release, which activates NK-1R receptors and inflammatory pathways. This inflammatory signaling somehow spreads to the partner eye — possibly through neural or systemic pathways — causing bilateral damage from unilateral exposure.

Could substance P blockers prevent cataracts?

Potentially. This study shows that blocking the substance P receptor (NK-1R) prevents UV-induced eye inflammation in mice. If this translates to humans, existing NK-1R drugs could be repurposed as eye drops for cataract and UV damage prevention.

Read the original research

UVR-B-induced NKR-1 Expression in Ocular Tissues is blocked by Substance P Receptor Antagonist Fosaprepitant in the Exposed as well as Unexposed Partner Eye.

Ocular immunology and inflammation, 29(5), 963-975

View on PubMed ↗Publisher’s paper ↗

Citation

Gross, Janine; Wegener, Alfred R; Kronschläger, Martin; Schönfeld, Carl-Ludwig; Holz, Frank G; Meyer, Linda M. (2021). UVR-B-induced NKR-1 Expression in Ocular Tissues is blocked by Substance P Receptor Antagonist Fosaprepitant in the Exposed as well as Unexposed Partner Eye.. Ocular immunology and inflammation, 29(5), 963-975. https://doi.org/10.1080/09273948.2019.1708414