Sensory Nerves Drive Abnormal Blood Vessel Growth in Dry Eye Disease Through Substance P

Inflamed sensory neurons in dry eye disease secrete substance P, which directly promotes blood vessel growth in the normally vessel-free cornea — and blocking substance P prevents it.

RPEP-04959AnimalModerate Evidence2020RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
animal
Evidence
Moderate Evidence
Sample
N=animal study
Participants
Mice with induced dry eye disease; trigeminal ganglion neurons and vascular endothelial cells in co-culture

What This Study Found

Sensory neurons from dry eye mice promoted vascular endothelial cell proliferation and tube formation via substance P signaling; blocking SP with spantide I prevented corneal neovascularization.

Key Numbers

DED neurons secreted higher SP levels; spantide I significantly reduced corneal neovascularization

How They Did This

Mouse dry eye model (desiccating stress); trigeminal ganglion neuron/VEC co-culture system; SP secretion measurement; spantide I (NK-1 antagonist) treatment in vivo and in vitro; siRNA knockdown of SP.

Why This Research Matters

Corneal neovascularization threatens vision in millions with dry eye disease. Targeting substance P could provide a new approach to prevent abnormal blood vessel invasion of the cornea.

The Bigger Picture

This reveals a direct nerve-to-blood-vessel communication pathway driven by substance P. The same mechanism may operate in other tissues where inflammation triggers unwanted blood vessel growth.

What This Study Doesn't Tell Us

Mouse model of dry eye; co-culture system is simplified compared to in vivo tissue; substance P may not be the only neuropeptide involved; human validation needed.

Questions This Raises

  • ?Would NK-1 receptor antagonists (like aprepitant, already FDA-approved for nausea) work as anti-angiogenic eye drops?
  • ?Is substance P-driven neovascularization relevant to corneal transplant rejection?
  • ?Do other neuropeptides (CGRP) also contribute to corneal angiogenesis?

Trust & Context

Key Stat:
Direct nerve-vessel link Sensory neurons directly promoted vascular cell proliferation and tube formation via substance P
Evidence Grade:
Moderate — strong mechanistic animal data with co-culture validation and multiple confirmatory approaches (antagonist + siRNA), but no human data.
Study Age:
Published in 2020; substance P's role in ocular inflammation is increasingly recognized.
Original Title:
Sensory neurons directly promote angiogenesis in response to inflammation via substance P signaling.
Published In:
FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 34(5), 6229-6243 (2020)
Authors:
Liu, Lingjia(2), Dana, Reza(6), Yin, Jia(2)
Database ID:
RPEP-04959

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study
What do these levels mean? →

Frequently Asked Questions

Why do blood vessels grow into the cornea during dry eye?

Inflamed nerves in the cornea release substance P, which signals blood vessel cells to multiply and form new vessels — a process that threatens the cornea's transparency and vision.

Could eye drops block substance P?

Potentially. Drugs that block the substance P receptor (NK-1 antagonists) already exist for other conditions and could theoretically be formulated as eye drops, but this hasn't been clinically tested yet.

Read More on RethinkPeptides

Cite This Study

RPEP-04959·https://rethinkpeptides.com/research/RPEP-04959

APA

Liu, Lingjia; Dana, Reza; Yin, Jia. (2020). Sensory neurons directly promote angiogenesis in response to inflammation via substance P signaling.. FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 34(5), 6229-6243. https://doi.org/10.1096/fj.201903236R

MLA

Liu, Lingjia, et al. "Sensory neurons directly promote angiogenesis in response to inflammation via substance P signaling.." FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 2020. https://doi.org/10.1096/fj.201903236R

RethinkPeptides

RethinkPeptides Research Database. "Sensory neurons directly promote angiogenesis in response to..." RPEP-04959. Retrieved from https://rethinkpeptides.com/research/liu-2020-sensory-neurons-directly-promote

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.