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Mechanisms of repigmentation induced by photobiomodulation therapy in vitiligo
摘要： Photobiomodulation (PBM) therapy is based on the exposure of biological tissues to low- level laser light (coherent light) or light- emitting diodes (LEDs; noncoherent light), leading to the modulation of cellular functions, such as proliferation and migration, which result in tissue regeneration. PBM therapy has important clinical applications in regenerative medicine. Vitiligo is an acquired depigmentary disorder resulting from disappearance of functional melanocytes in the involved skin. Vitiligo repigmentation depends on available melanocytes derived from (a) melanocyte stem cells located in the bulge area of hair follicles and (b) the epidermis at the lesional borders, which contains a pool of functional melanocytes. Since follicular melanoblasts (MBs) are derived from the melanocyte stem cells residing at the bulge area of hair follicle, the process of vitiligo repigmentation presents a research model for studying the regenerative effect of PBM therapy. Previous reports have shown favourable response for treatment of vitiligo with a low- energy helium- neon (He- Ne) laser. This review focuses on the molecular events that took place during the repigmentation process of vitiligo triggered by He- Ne laser (632.8 nm, red light). Monochromatic radiation in the visible and infrared A (IRA) range sustains matrix metalloproteinase (MMP), improves mitochondrial function, and increases adenosine triphosphate (ATP) synthesis and O2 consumption, which lead to cellular regenerative pathways. Cytochrome c oxidase in the mitochondria was reported to be the photoacceptor upon which He- Ne laser exerts its effects. Mitochondrial retrograde signalling is responsible for the cellular events by red light. This review shows that He- Ne laser initiated mitochondrial retrograde signalling via a Ca2+- dependent cascade. The impact on cytochrome c oxidase within the mitochondria, an event that results in activation of CREB (cyclic- AMP response element binding protein)- related cascade, is responsible for the He- Ne laser promoting functional development at different stages of MBs and boosting functional melanocytes. He- Ne laser irradiation induced (a) melanocyte stem cell differentiation; (b) immature outer root sheath MB migration; (c) differentiated outer root sheath MB melanogenesis and migration; and (d) perilesional melanocyte migration and proliferation. These photobiomodulation effects result in perifollocular and marginal repigmentation in vitiligo.
关键词： mechanism,photobiomodulation therapy,melanocyte precursors,vitiligo,repigmentation
更新于2025-09-19 17:15:36
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Multi‐Factors Associated With Efficacy and Adverse Events of Fractional Erbium:YAG Laser‐Assisted Delivery of Topical Betamethasone for Stable Vitiligo: A Retrospective Analysis
摘要： Background and Objectives: Although topical corticosteroids are still the first‐line option for vitiligo, its efficacy is still unsatisfactory for stable vitiligo. A few studies have focused on laser‐assisted drug delivery (LADD) but were limited by their sample deficiency and analyses of the influencing factors. To determine the efficacy, adverse events, and their influencing factors of fractional erbium: yttrium‐aluminum‐garnet (Er:YAG) laser‐assisted topical delivery of corticosteroids in stable vitiligo. Study Design/Materials and Methods: We retrospectively reviewed 1,026 lesions in 684 patients with stable vitiligo who underwent treatment with fractional Er:YAG laser‐assisted delivery of topical compound betamethasone solution between January 2014 and December 2017. Multi‐factors associated with different outcomes were analyzed by logistic regression in this study. Results: A total of 413 of 1,026 lesions (40.3%) were effective 12 months after the first treatment. Age (<14 years old), disease duration (<1 year), lesion location (on face and neck), hairy lesions, and drug concentration were independent factors associated with effective repigmentation. A common adverse event was hyperpigmentation (14.4%), which was highly correlated with 22% density. Conclusions: Fractional Er:YAG laser‐assisted delivery of topical compound betamethasone is a good option for the management of vitiligo. The treatment may be suggested in these situations: younger patients, shorter disease duration, and lesions on the face and neck with hair. The appearance of white hair in the lesion area does not affect our confidence in vitiligo treatment. Density >22% may cause hyperpigmentation, but it does not significantly contribute to the efficacy.
关键词： betamethasone,laser‐assisted drug delivery,fractional Er:YAG laser,vitiligo,repigmentation
更新于2025-09-12 10:27:22
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Q-Switched Alexandrite Laser and Topical 20% Monobenzyl Ester of Hydroquinone Removal of Tacrolimus-Induced Repigmentation (After Complete Depigmentation With 20% Monobenzyl Ether of Hydroquinone)
摘要： Monobenzyl ester of hydroquinone (MBEH) has been used as a bleaching agent in patients with widespread vitiligo. The depigmentation from bleaching agents is not permanent, and pigmentation has been reported to spontaneously recur. We report a case of repigmentation in a completely depigmented patient who was using topical tacrolimus. A 63-year-old fair-skinned Indian woman presented to our clinic with multiple irregular dark brown macules on her cheeks, ears, and periorbital region. She developed vitiligo in her early 20s, and because of its extensive nature, she elected to undergo treatment with topical 20% MBEH in 1989. Within 1 year, she achieved total body depigmentation. Twenty-two years after her treatment with MBEH, she developed eyelid dermatitis for which she was prescribed topical tacrolimus 0.03% ointment. Over several weeks, she developed dark brown pigmentation in all areas treated with tacrolimus. She presented to our clinic for treatment of the pigmented areas, which she noted was identical to her natural dark brown skin tone. The tacrolimus was discontinued, and she was initially treated with 755-nm Q-switched (QS) alexandrite laser (8–8.5 J/cm2, 3 mm, 50 ns) at monthly intervals. Notably, with her recent history of eyelid dermatitis, topical MBEH was not chosen because of the initial treatment due to its known adverse effect of irritant dermatitis. After each treatment with the QS alexandrite, she had partial resolution, but in the subsequent 2 to 3 weeks, the pigmentation returned. After 2 treatments with the QS alexandrite alone and no recurrence in eyelid dermatitis, compounded topical 20% MBEH (Park Pharmacy, Irvine, CA) was added to her regimen to apply daily to the pigmented areas. After 3 additional laser treatments with concomitant topical therapy, the pigmentation resolved completely. These results have been maintained for 3 months after the last treatment.
关键词： MBEH,tacrolimus,vitiligo,repigmentation,Q-switched alexandrite laser
更新于2025-09-12 10:27:22
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Long-term outcomes of laser treatment for congenital melanocytic nevi
摘要： Background: Although various laser treatments have been tried for congenital melanocytic nevi (CMNs), only small retrospective studies with short-term follow-up had been done to assess outcomes. Objective: We analyzed the long-term outcomes of laser treatment for CMN and compared these outcomes with those of a combination treatment including partial excision and lasers. Methods: Patients with CMN treated with lasers were retrospectively reviewed, and patients with [3 years of follow-up were grouped as the long-term follow-up group. Results: A total of 67 cases of CMN were reviewed. Among 20 patients (20/52, 38.5%) with near total clearance during laser-only treatment, 11 patients were in the long-term follow-up group, and 5 of 11 showed repigmentation. In total, 15 patients showed repigmentation regardless of clearance, and the mean period until repigmentation was 3.93 years from the initial treatment. Patients with partial excision and laser combination treatment showed higher Investigator’s Global Assessment scores, fewer laser treatments, and shorter treatment periods compared with patients with laser-only treatment. Limitations: This is a retrospective study, and various laser devices were used. Conclusion: More than 4 years of follow-up is required to evaluate the efficacy of lasers in CMN, and partial excision and laser combination treatment might be an effective treatment option.
关键词： repigmentation,partial excision,laser treatment,congenital melanocytic nevi
更新于2025-09-11 14:15:04