What’s new in hair — July 2016 | Dr. Yuval Ramot

Effects of imiquimod on hair follicle stem cells and hair cycle progression

J Invest Dermatol. 2016 Jul 1. pii: S0022-202X(16)32086-3. doi: 10.1016/j.jid.2016.06.613. [Epub ahead of print]

Application of imiquimod (IMQ) on the skin results in severe inflammation. Therefore, it is used in mice as a model for psoriasiform-like skin inflammation. While the effects of IMQ on the epidermis are well characterized, its effects on the hair follicle (HF) are still unknown. In this study, Amberg et al. evaluated the effects of IMQ on the HF and whether the different hair cycles affect the skin response. They show that application of IMQ during mid and late telogen results in rapid anagen induction. This is thought to result from a decrease in resident macrophages, which inhibit anagen induction, and an increase in inflammatory infiltrating macrophages, which stimulate its induction. They conclude that there are significant differences in the reaction of the skin to IMQ treatment based on the different hair cycle stages, and recommend performing the IMQ assays during mid and late telogen, when the most significant differences in immune cell composition are present.

 

Germline MC1R status influences somatic mutation burden in melanoma

Nat Commun. 2016 Jul 12;7:12064. doi: 10.1038/ncomms12064.

What is the connection between the red hair phenotype and the risk for melanoma? In this study, Robles-Espinoza et al. checked the contribution of the R allele in MC1R, which is strongly associated with the red hair phenotype, to the somatic mutation landscape of sporadic melanomas. They found that melanomas from individuals with the R allele have a higher somatic mutational burden, which translates to an expected mutational burden of 21 more years. Interestingly, they found that the people with even one R allele, which does not results in red hair, are still highly susceptible to the adverse mutagenic effects of UV light. Collectively, this work contributes to our understanding of the pathogenesis of melanoma in this high-risk group of red-haired people.

 

Gaseous and particulate content of laser hair removal plume

JAMA Dermatol. 2016 Jul 6. doi: 10.1001/jamadermatol.2016.2097. [Epub ahead of print]

Lase hair removal is one of the most popular cosmetic procedures in the world. This technique, which aims to thermally destroy the bulge cells, is accompanied by the formation of malodorous and visible plume. In this study, hairs from two individuals were taken, and the aerosolized content after laser treatment was measured using several methods. Sixty-two organic compounds were identified, of which 13 are known or suspected carcinogens, and more than 20 are toxins or irritants. The release of these compounds during the laser hair removal procedure may lead to health problems. Therefore, the authors recommend the installation of effective exhaust systems that include chemical extraction and particulate capture in the treatment rooms.

 

CXCR3 blockade inhibits T cell migration into the skin and prevents development of alopecia areata.

J Immunol. 2016 Jul 13. pii: 1501798. [Epub ahead of print]

While the immunopathogenesis of alopecia areata (AA) is not entirely clear, recent evidence suggests that the main immune effectors are the NK-type CD8+ NKG2D+ T cells, which infiltrate the hair follicle (HF). Previous studies have shown that the IFN-inducible chemokines (CXCL9/10/11) and the CXCR3 receptor are involved in AA development, and their upregulation may result in the accumulation of the effector T cells around the HF. In this paper, Dai et al used the C3H/HeJ mice and lesions from AA patients to investigate the role of CXCR3 in AA development. They showed that CXCR3 is upregulated in AA lesions, and by treating mice with blocking antibodies to CXCR3 they could prevent AA induction and the accumulation of NKG2D+ CD8+ T cells in the skin and associated lymph nodes. Taken together, these results underscore the importance of CXCR3 to AA pathogenesis, and highlight this receptor as a potential target for future therapies for AA.

 

Health-related quality of life (HRQoL) among patients with alopecia areata (AA): A systematic review

J Am Acad Dermatol. 2016 Jul 16. pii: S0190-9622(16)30137-2. doi: 10.1016/j.jaad.2016.04.035. [Epub ahead of print]

Emotional and psychological distress is commonly experienced by alopecia areata (AA) patients. In this study, Liu et al performed a systematic review of all published studies that evaluated health-related quality of life (HRQoL) in AA patients. Eleven studies met the inclusion criteria, and the total sample size of patients was 1986. Overall, patients with AA consistently demonstrated reduced HRQoL, with greater severity corresponding to lower HRQoL. These lower HRQoL scores were also evident in pediatric patients and their caretakers. The scores reported by the patients were similar to those observed in other chronic dermatological skin conditions such as psoriasis or atopic dermatitis. These results emphasize the fact that AA, although not considered by many to be a “serious” medical conditions, has detrimental effects on the patients, and highlight the need for better treatments for this disorder.

 

Intramuscular triamcinolone acetonide: An undervalued option for refractory alopecia areata

J Dermatol. 2016 Jul 23. doi: 10.1111/1346-8138.13533. [Epub ahead of print]

Treatment of severe alopecia areata (AA) is a challenge, and systemic corticosteroids are still considered the best treatment option for the recalcitrant cases. In this study, Seo et al report their 5-year experience with using intramuscular (i.m.) triamcinolone acetonide (TAC) for severe AA in 27 patients. Response rate was 63%, with a negative correlation between the degree of hair loss before treatment and hair regrowth following treatment. The only adverse events were observed in female patients (all four patients that were treated), and included dysmenorrhea and decreased bone mineral density. The authors conclude that i.m. TAC may be a therapeutic option for severe AA, especially in male patients. Taking into consideration the retrospective nature of this study and the small number of patients evaluated, it is clear that larger randomized controlled trials are necessary.

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