Scar Reinnervation May Explain Pain, Pruritis Symptoms
Increased levels of sensory neuropeptides can cause unpleasant symptoms during healing
WEDNESDAY, Sept. 27 (HealthDay News) -- The pain, numbness and pruritis associated with cutaneous scars may be caused by increased levels of the sensory neuropeptides calcitonin gene-related peptide (CGRP) and substance P (SP) that form during healing, according to a report in the September issue of the Journal of Plastic, Reconstructive & Aesthetic Surgery.
Giorgio Terenghi, Ph.D., and colleagues at the University of Manchester in the U.K., analyzed wounds in mice using immunohistochemical stains for pan-neuronal markers and sensory neuropeptides. Nerve fiber density and revascularization were quantified and localized at multiple sites.
The peripheral and central wound sites were comparable in terms of reinnervation and revascularization patterns, and the levels of CGRP and SP peaked between 14 and 42 days. At 84 days, all factors had decreased to levels found in unwounded skin except for SP, which was twice as dense as in unwounded skin.
"From these findings we hypothesize that SP in C fibers might be a mediator of the sensory symptoms of mature scars, either as a sensory neurotransmitter, or by leading to mast cell degranulation and histamine release. CGRP in C and A delta fibers might have a role in healing wounds or immature scars as a mediator of the healing process, and/or as a sensory neurotransmitter," the authors conclude.
The study was supported by Renovo Ltd.