Substance P Promotes Wound Healing Primarily Through the NK-1 Receptor by Stimulating Cell Migration and TGF-β1 Release | Research

The takeaway

Substance P stimulates fibroblast proliferation, migration, and TGF-β1 release to promote wound healing, with the NK-1 receptor being the primary mediator — blocking it abolishes wound healing effects.

NK-1 blockade abolished wound healing
Blocking the NK-1 receptor with spantide II prevented substance P from stimulating fibroblast migration, confirming it as the primary wound healing receptor

What the researchers found

Substance P alone significantly stimulated fibroblast proliferation and migration in both scratch assays (horizontal) and transwell assays (vertical) over 24 hours. Blocking the NK-1 receptor with spantide II abolished substance P's ability to stimulate cell migration. NK-2 receptor antagonism also significantly reduced migration but was less effective than NK-1 blockade. Combined NK-1 and NK-2 antagonism produced the greatest inhibition. TGF-β1 levels were significantly elevated in substance P-treated cell supernatants, while all receptor antagonist combinations showed significantly lower TGF-β1 levels than substance P alone.

Why it matters

Chronic non-healing wounds (diabetic foot ulcers, pressure sores, venous leg ulcers) affect millions worldwide and cost healthcare systems billions. Understanding the specific receptor mechanism behind substance P's wound healing effects opens the door to targeted peptide-based wound therapies. If NK-1 receptor activation is the key, then substance P analogs or NK-1 agonists could be developed as topical wound treatments.

How the study worked

In vitro study using buffalo fetal fibroblast cultures. Wound healing was modeled using scratch assays (horizontal migration) and transwell assays (vertical migration). Substance P was tested alone and in combination with specific receptor antagonists: spantide II (NK-1 antagonist), an NK-2 antagonist, and both together. TGF-β1 levels in cell culture supernatants were measured by immunoassay. Cell proliferation was also assessed.

What this study cannot tell us

This was an in vitro study using buffalo fetal fibroblasts, which may not perfectly represent human adult skin wound healing biology. No in vivo wound healing experiments were conducted. The study used a single cell type (fibroblasts) and did not examine substance P's effects on other wound healing cells (keratinocytes, endothelial cells, immune cells). TGF-β1 was the only growth factor measured, though substance P likely affects multiple healing mediators.

How to read the evidence

This is an in vitro study using cell culture models of wound healing. The systematic use of specific receptor antagonists to dissect the mechanism is well-designed, but findings need validation in animal wound models and ultimately human clinical studies.

When this study was published

Published in 2023, this study builds on earlier work demonstrating substance P's wound healing potential and advances mechanistic understanding through receptor-specific analysis.

The bigger picture

Neuropeptides are increasingly recognized for roles beyond nervous system signaling — they regulate immune responses, inflammation, and tissue repair. Substance P's wound healing properties connect the nervous system directly to tissue regeneration, explaining why denervated wounds (in diabetic neuropathy, for example) heal poorly. NK-1 receptor agonists could potentially restore this healing signal in conditions where nerve-derived substance P is deficient.

Questions still open

Could topical substance P or NK-1 receptor agonists accelerate healing of chronic wounds like diabetic foot ulcers?
Does substance P deficiency in diabetic neuropathy contribute to impaired wound healing through reduced NK-1 activation?
Would combining substance P with other wound healing peptides produce synergistic effects?

Common questions

How does a pain-related neuropeptide help wounds heal?

Substance P is released by nerve endings near wound sites and does much more than signal pain — it stimulates fibroblasts (the main wound repair cells) to multiply and migrate to fill the wound, and triggers the release of TGF-β1, a powerful growth factor that drives tissue repair. This study showed that these healing effects work primarily through the NK-1 receptor on fibroblasts.

Why do diabetic wounds heal so poorly?

Diabetes often damages nerve endings (neuropathy), which means less substance P is released at wound sites. Since this study shows substance P is a key driver of fibroblast migration and wound healing via the NK-1 receptor, nerve damage could directly impair wound repair. Restoring substance P signaling — through topical peptide application or NK-1 receptor agonists — could potentially help diabetic wounds heal faster.

Read the original research

Substance P, a Neuropeptide, Promotes Wound Healing via Neurokinin-1 Receptor.

The international journal of lower extremity wounds, 22(2), 291-297

View on PubMed ↗Publisher’s paper ↗

Citation

Kant, Vinay; Mahapatra, Puspendra S; Gupta, Vijayta; Bag, Sadhan; Gopalakrishnan, Anu; Kumar, Dhirendra; Kumar, Dinesh. (2023). Substance P, a Neuropeptide, Promotes Wound Healing via Neurokinin-1 Receptor.. The international journal of lower extremity wounds, 22(2), 291-297. https://doi.org/10.1177/15347346211004060