What’s new in hair — July 2017 | Dr. Yuval Ramot
A multi-scale model for hair follicles reveals heterogeneous domains driving rapid spatiotemporal hair growth patterning
Elife. 2017 Jul 11;6. pii: e22772. doi: 10.7554/eLife.22772. [Epub ahead of print]
The mechanisms that control hair regeneration and hair cycling are still incompletely understood, and they are thought to be controlled by a complex set of activators/inhibitors. It is postulated that interactions between neighbouring hair follicles (HFs) allow the self-organization of dorsal hairs into dynamic patterns. Wang et al. present a unified three-dimensional and stochastic modeling framework, which provides details on hair regeneration. Using this model, they show that the whole skin acts as a heterogenous regenerative field, with areas of fast, slow, and very slow hair renewal. The hair cycle waves start at the ventrum and spread to the dorsum in a bilateral pattern. The waves halt at the border with hyper-refractory ear skin and break at anatomical locations that are non-propagating, such as the eyelids and ears. The main players in controlling hair regeneration dynamics are WNT and BMP, which are active in all the locations examined in this study. This suggests that these two modulators provide a general “molecular language” for hair growth, which allows means for hair-to-hair communications in all anatomic domain boundaries.
Biochem Biophys Res Commun. 2017 Jul 13. pii: S0006-291X(17)31411-0. doi: 10.1016/j.bbrc.2017.07.069. [Epub ahead of print]
Sphingolipids have been postulated to take part in the regulation of hair follicle cycling. Therefore, Park et al have investigated the effects of a new psudoceramide, called bis-oleamido isopropyl alcohol (BOI), on hair growth in several models. In an ex vivo model, BOI increased hair elongation of human occipital scalp hair follicles in culture. In addition, topical application of BOI on shaved dorsal skin of C57BL/6 mice resulted in premature anagen onset when compared to vehicle. When dermal papilla cells in culture were treated with BOI, increased levels of sphingolipids were observed in comparison to the vehicle-treated cells, suggesting that the hair growth promoting effects of BOI might be mediated by stimulation of do novo synthesis of sphingolipids in dermal papilla cells. While these data should be confirmed by additional studies, and the underlying mechanisms for hair growth should be further elucidated, BOI seems to be a new promising therapeutic topical modality for hair loss.
J Am Acad Dermatol. 2017 Jul 14. pii: S0190-9622(17)31801-7. doi: 10.1016/j.jaad.2017.05.045. [Epub ahead of print]
Frontal fibrosing alopecia (FFA) is a primary scarring alopecia that shows increased incidence in recent years. It is most prevalent in postmenopausal women, and its occurrence in men is considered rare. In this study, Tolkachjov et al. describe the clinical and histopathological characteristics in seven men with FFA and their response to treatment. They found that the clinicopathologic characteristics of the patients in this cohort were similar to the ones reported in women with FFA, although involvement of the sideburns and facial hair was seen more frequently in men than in women. The authors also provide proposed criteria for the diagnosis of FFA, which include two major and four minor criteria. The authors suggest that to make the diagnosis of FFA the patient should have either 2 major criteria or 1 major and 2 minor criteria. Further studies are needed in order to establish the findings in this study, which are based on a limited number of patients with a limited follow-up time of some of the patients.
J Cosmet Dermatol. 2017 Jul 20. doi: 10.1111/jocd.12379. [Epub ahead of print]
Another interesting article on frontal fibrosing alopecia (FFA) has been published this month by Lis-Święty et al. Treatments for FFA are more likely to be effective if they are implemented during the active inflammatory phase of the disease. Therefore, assessing the inflammation status in the affected skin is of importance. Since skin inflammation process has been previously suggested to be reflected by changes in local skin temperature, the authors used infrared thermographic imaging to assess the activity of the inflammatory process in FFA, combined with a dermoscopy examination. They found that using thermal imaging combined with dermoscopy provided the most accurate clinical assessment of active FFA. Together, this combination provided a positive predictive value of 90%. Therefore, the authors suggest that thermal imaging would be used as a complementary tool in FFA diagnosis.
Establishing and Prioritising Research Questions for the Prevention, Diagnosis and Treatment of Hair Loss (excluding Alopecia Areata): The Hair Loss Priority Setting Partnership
Br J Dermatol. 2017 Jul 17. doi: 10.1111/bjd.15810. [Epub ahead of print]
Unfortunately, as also frequently reflected in our paper review, our understanding of the pathogenesis of hair disorders is limited, and the ability to treat hair conditions is still many times inadequate. To address the treatment uncertainties in hair loss condition, the British Hair and Nail Society has established the Hair Loss Priority Setting Partnership to present priorities for UK hair research. Treatment uncertainties were submitted by more than 900 participants, and these were analysed by a steering group comprised of patients, dermatologists, a psychologist, a trichologist and a general practitioner. This process resulted in a list of 10 uncertainties that seem to be of top importance in relation to management, prevention, diagnosis and treatment of hair loss conditions. This list can help in guiding future research efforts in the field of hair loss conditions.
Long-Term Prognosis of Alopecia Totalis and Alopecia Universalis: A Longitudinal Study with More than 10 Years of Follow-Up: Better than Reported
Dermatology. 2017 Jul 14. doi: 10.1159/000477458. [Epub ahead of print]
It is usually thought that patients with alopecia totalis (AT) and alopecia universalis (AU) can expect a poor prognosis, and previous studies have shown that the chances for hair regrowth is less than 10%. Jang et al. have performed a retrospective chart review, evaluating 70 patients with AT or AU. They found that the full hair regrowth rate in all alopecia areata patients was 17.1%, and that 24.2% had more than 90% hair regrowth. AU patients had a lower chance of hair regrowth, and a lower tendency for hair regrowth was observed in female patients, early onset disease, long period of alopecia, a positive family history of alopecia areata, nail changes, and atopic diseases. This study is the largest to evaluate long term outcomes of AT and AU, but it has some limitations, mainly related to the fact that it was a chart review and phone survey study. Nevertheless, compared to previous studies, it suggests a better outcome for AT and AU patients.