Pro-Inflammatory Cytokine Cascade in Human Plucked Hair

Abstract

Using reverse transcriptase polymerase chain reaction we showed that freshly plucked human anagen hair expressed both type 1 (80 kD) and type 2 (60 kD) interleukin (IL)-1 receptor mRNAs. The IL-1 receptor type 1 was functional since after in vitro stimulation of plucked hair with IL-1Α, we observed the induction of mRNA(s) for the inflammatory cytokines IL-1Β, tumour necrosis factor Α and IL-6 as well as for the chemokines monocyte chemotactic and activating factor and IL-8. In addition, the growth of dissected human anagen hairs in culture in vitro was significantly and dose-depen-dently inhibited by IL-1Α as a consequence of hair bulb degradation. These observations, together with those of other authors in IL-1Α transgenic mice evidence the inhibitory role of IL-1 on human hair growth. Therefore, in order to identify individuals with high inflammatory potential in their hair follicle environment, we designed a rapid and simple assay to detect variations in the level of IL-1Α production in the overnight supernatant of plucked hairs in culture. We observed that 32.7% of the specimens from the volunteers tested (n = 116) could be considered highly inflammatory in terms of IL-1Α production. Altogether, these results suggest that in alopecia androgenetica, hair growth might be negatively influenced by IL-1, directly produced by the outer root sheath keratinocytes. Consequently, identifying the ‘inflammatory alopecic individual’ might be of clinical interest to discriminate among individuals for whom anti-IL-1 strategies might be of therapeutic relevance.

Female Pattern Hair Loss and its Relationship to Permanent/Cicatricial Alopecia: A New Perspective

“…That the portion of the follicle in the bulge region, where a population of follicular stem cells lie, may be a particularly attractive target for inflammatory cytokines has been shown in patients with graft versus host disease where there appears to be some selective targeting of the undifferentiated stem cells of the hair follicle (Sale et al, 1994). Furthermore, IL-1a, a proinflammatory cytokine, has been shown to inhibit hair growth and fiber production in whole organ culture albeit with interindividual differences (Harmon andNevins, 1993 andMahe, Buan, Billoni et al, 1996).…”

EEMCO Guidance for the Assessment of Hair Shedding and Alopecia

“…Tumor necrosis factor ·, vascular intestinal peptide and proopiomelanocortin peptides including ·-melanocyte-stimulating hormone as well as their receptors are present in the human pilosebaceous follicles [51]. Interleukin 1 receptors are also present in anagen hairs [52]. This cytokine network may stimulate or antagonize perifollicular inflammation at the distal part of the follicle.…”

“…The complex interactions between hair growth, sebaceous gland functions, angiogenesis [69,70], micro-inflammation and its counterpart immuno-suppression [51][52][53][54][55][56][57] and neuroendocrine influences [41,71] are incompletely characterized. The environmental impact including solar irradiation [49,50] and commensal microorganisms [56,59,72,73] cannot be neglected either.…”

Androgenic alopecia and dutasteride in hair mesotherapy: A short review

“…This process that occurs at least in one-third of AGA cases [10,[26][27][28][29] initiates at infundibulum mediated by bacteria, UV irradiation, chemical and/or mechanical stress. Keratinocytes rapidly respond to stressors releasing interleukin-1α (IL-1α) [30,31] that was shown to inhibit hair growth in vitro [32][33][34]. A transcriptional cascade is activated, increasing pro-inflammatory cytokines (IL-1α, IL-1β, TNFα), chemokines (IL-8, MCPs), collagenases and others.…”