Dose‐response of human follicles during laser‐based hair removal: <i>Ex vivo</i> photoepilation model with classification system embracing morphological and histological features

Vlimmeren, Marijke A. A. van; Raafs, Bianca; Westgate, Gillian; Beijens, Linda G. M.; Uzunbajakava, N.

doi:10.1002/lsm.23085

Cited by 3 publications

(1 citation statement)

References 32 publications

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“…The substantial intraepithelial apoptosis observed after epilation may be a consequence of this phenomenon and is reminiscent of intrafollicular apoptosis in mice after wax epilation [66, 119] or after light‐induced hair removal [8, 9, 120]. While we did not see any evidence of necrosis, which can be seen under laser hair removal [8, 9, 121], we observed persistent focal thinning of the HF BM. It is conceivable that the increased numbers of perifollicular MHC class II + cells (such as macrophages) and mast cells observed post‐epilation could secrete or activate matrix metalloproteinases (MMPs) that participate in BM degradation [122–125].…”

Section: Discussionmentioning

confidence: 63%

Mechanical epilation exerts complex biological effects on human hair follicles and perifollicular skin: An ex vivo study approach

Bertolini,

Gherardini,

Chéret

et al. 2023

Intern J of Cosmetic Sci

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ObjectiveElectrical epilation of unwanted hair is a widely used hair removal method, but it is largely unknown how this affects the biology of human hair follicles (HF) and perifollicular skin. Here, we have begun to explore how mechanical epilation changes selected key biological read‐out parameters ex vivo within and around the pilosebaceous unit.MethodsHuman full‐thickness scalp skin samples were epilated ex vivo using an electro‐mechanical device, organ‐cultured for up to 6 days in serum‐free, supplemented medium, and assessed at different time points by quantitative (immuno‐)histomorphometry for selected relevant read‐out parameters in epilated and sham‐epilated control samples.ResultsEpilation removed most of the hair shafts, often together with fragments of the outer and inner root sheath and hair matrix. This was associated with persistent focal thinning of the HF basal membrane, decreased melanin content of the residual HF epithelium, and increased HF keratinocyte apoptosis, including in the bulge, yet without affecting the number of cytokeratin 15+ HF epithelial stem cells. Sebocyte apoptosis in the peripheral zone was increased, albeit without visibly altering sebum production. Epilation transiently perturbed HF immune privilege, and increased the expression of ICAM‐1 in the bulge and bulb mesenchyme, and the number of perifollicular MHC class II+ cells as well as mast cells around the distal epithelium and promoted mast cell degranulation around the suprabulbar and bulbar area. Moreover, compared to controls, several key players of neurogenic skin inflammation, itch, and/or thermosensation (TRPV1, TRPA1, NGF, and NKR1) were differentially expressed in post‐epilation skin.ConclusionThese data generated in denervated, organ‐cultured human scalp skin demonstrate that epilation‐induced mechanical HF trauma elicits surprisingly complex biological responses. These may contribute to the delayed re‐growth of thinner and lighter hair shafts post‐epilation and temporary post‐epilation discomfort. Our findings also provide pointers regarding the development of topically applicable agents that minimize undesirable sequelae of epilation.

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Section: Discussionmentioning

confidence: 63%

Mechanical epilation exerts complex biological effects on human hair follicles and perifollicular skin: An ex vivo study approach

Bertolini,

Gherardini,

Chéret

et al. 2023

Intern J of Cosmetic Sci

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Efficacy and Pain Tolerance of Alexandrite Laser Hair Removal at Different Stages of the Menstrual Cycle

Karanfil,

Görgü

2024

Aesthetic Surgery Journal

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Background Several different parameters play a role in the transition of hair follicles to the anagen phase, with the role of androgens, progesterone, estrogen hormones, and receptors being significant. Objectives The effectiveness of Laser Hair Removal (LHR) and pain tolerance during application were investigated during three different phases of the menstrual cycle. Methods 48 axillae were randomly divided into three groups: menstruation, ovulation, and luteal. Three laser sessions were performed on each axilla at a one-month interval. Blood hormone levels were measured in the patients. Alexandrite laser was used during LHR sessions, before each LHR session and one month after the third session, hair follicles in 4 cm2 areas in the center of the axillae were counted. Patients self-assessed the pain they felt during the laser application in each session using visual pain scale. Results The average values for hair counting in the groups were as follows: MO = 47.6, M1 = 27.4, M2 = 16.1, M3 = 9.9, O0 = 41.8, O1 = 21.1, O2 = 13.8, O3 = 8.6, L0 = 49.4, L1 = 27.1, L2 = 15.1, L3 = 9.8. The average values for Visual Analog Scale (VAS) scores in the groups were: M1 = 3.94, M2 = 3.06, M3 = 1.94, O1 = 3.50, O2 = 3.06, O3 = 1.69, L1 = 3.63, L2 = 2.50, and L3 = 1.56. Statistical analysis was conducted using Tukey post hoc analysis after ANOVA. Conclusions The results of LHR are not affected by changes in hormone levels during the menstrual cycle in women. Although not statistically significant, it has been observed that pain tolerance during laser application is lower during the menstruation cycle.

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Remoção de Pelos com LED de Alta Potência – Avaliação por Termografia Infravermelha: um estudo piloto

Lopes-Martins¹,

Moraes²,

Bueno³

et al. 2021

RSD

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Introdução. A fotoepilação usa diferentes fontes de luz para remover pelos indesejáveis. As fontes de luz mais comuns usadas para depilação permanente são os lasers de diodo e a luz pulsada intensa. A depilação com luz assistida baseia-se na destruição da unidade folicular. A capacidade de remover pelos sem danificar a pele ao redor é baseada na fototermólise seletiva, no entanto, a ocorrência de efeitos colaterais como dor e queimação na pele é relatada para lasers e luz intensa pulsada. Objetivo. Aqui nós investigamos em um estudo piloto de uma tecnologia recentemente aprovada de LED de alta potência com sonda resfriada, possíveis mudanças na temperatura da pele avaliadas por termografia infravermelha, bem como sensibilidade aguda e 24h e dor por Escala Visual Analógica. Métodos. Cinco participantes sem restrições de fototipo de pele foram incluídos no estudo piloto. A temperatura da pele foi monitorada antes e depois (30s, 5 e 10 min) após a fotoepilação com LED, além de dor instantânea e 24h. Resultados. Nem aumentos significativos na temperatura da pele e nenhuma dor 24 horas ou quaisquer efeitos colaterais foram relatados. A dor aguda durante o procedimento variou de 2 a 4 (VAS). Conclusão. LED de alta potência com sonda resfriada parece ser uma tecnologia segura e eficiente para fotoepilação.

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Dose‐response of human follicles during laser‐based hair removal: Ex vivo photoepilation model with classification system embracing morphological and histological features

Cited by 3 publications

References 32 publications

Mechanical epilation exerts complex biological effects on human hair follicles and perifollicular skin: An ex vivo study approach

Mechanical epilation exerts complex biological effects on human hair follicles and perifollicular skin: An ex vivo study approach

Efficacy and Pain Tolerance of Alexandrite Laser Hair Removal at Different Stages of the Menstrual Cycle

Remoção de Pelos com LED de Alta Potência – Avaliação por Termografia Infravermelha: um estudo piloto

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