Possible involvement of neuropeptidergic sensory nerves in alopecia areata

Abstract

Alopecia areata (AA) is a dermatosis involving the sudden occurrence of bald patches on the scalp. Although the aetiology is unknown, experimental data indicate that cutaneous microcirculation plays an important role. The skin is richly innervated by neuropeptidergic sensory nerves that help regulate microvascular circulation. This study shows a reduction of cutaneous levels of substance P and calcitonin gene-related peptide (CGRP) but not of vasoactive intestinal polypeptide in scalp biopsies from patients with AA. Laser-Doppler flowmetry was used to study microcirculation of the scalp. Results indicate that patients with AA have lower basal blood flow and greater vasodilatation following intradermal CGRP injection than control subjects. A vascular hyper-reactivity to vasodilatatory substances such as neuropeptides, probably because of the lack of these substances, is hypothesized.

Neuronal plasticity of the “brain–skin connection”: stress-triggered up-regulation of neuropeptides in dorsal root ganglia and skin via nerve growth factor-dependent pathways

“…Hordinsky et al [48] reported increased neuronal CGRP immunoreactivity around eccrine glands of AA patients, while Meyronet et al [49] found decreased immunoreactivity of skin and hair follicles in the areas of lesions compared to biopsies from healthy scalp regions. Lower levels of CGRP were detected when comparing biopsies from AA patients with those from healthy controls [50]. Other mediators like the neuropeptide neurotensin [51] or the corticotropin-releasing hormone (CRH) [52] via induction of mast cell degranulation might Representative examples of flourogold-traced dorsal root ganglia from nonstressed (e) and stressed mice (g).…”

Adrenomedullin is induced by hypoxia and enhances pancreatic cancer cell invasion

“…Cells were incubated in the absence or presence of the indicated concentrations of recombinant bioactive ADM protein (rADM) 1,[30][31][32] (Merck Biosciences GmbH, Schwalbach, Germany), ADM receptor antagonist; Human Calcitonin Gene Related Peptide I [33][34][35] (Merck Biosciences GmbH, Schwalbach, Germany) for 48 hr. Then, 10 ll MTT (5 mg/ml in PBS) were added to each well and incubated for 4 hr at 37°C.…”

Botulinum Toxin Off-Label Use in Dermatology: A Review

“…Alopecia areata (AA) is a common dermatosis that causes patches of nonscarring hair loss on the scalp or eyebrows, beard, and less frequently on other skin areas [60,61] . The autoimmune hypothesis is the most exam- ined, but the pathophysiology of AA appears complex [60] ; in 1994, Paus et al [61] demonstrated that substance P (SP) may play a role in the neural control of hair growth.…”

“…The autoimmune hypothesis is the most exam- ined, but the pathophysiology of AA appears complex [60] ; in 1994, Paus et al [61] demonstrated that substance P (SP) may play a role in the neural control of hair growth. They suggested an interesting interaction in epithelial-mesenchymal-neuroectodermal system of the hair follicle.…”

“…They suggested an interesting interaction in epithelial-mesenchymal-neuroectodermal system of the hair follicle. Based on these data, Rossi et al [60] showed decreased calcitonin gene-related peptide (CGRP) and SP levels in the scalp biopsy of patients affected by AA and postulated that this may explain the reduced basal microvascular blood flow observed in patients with alopecia. The first case of alopecia cured with BoNT-A injections was a 34-year-old woman affected by a cephalalgic alopecia, a severe form of headache with a burning pain of the scalp, allodynia, and hair loss in involving areas, similar to AA [62] .…”