Horizontal and vertical pigment spread into surrounding piebald epidermis and hair follicles after suction blister epidermal grafting

Comparative outcomes of autologous cultured melanocytes transplantation and non-cultured epidermal cell suspension transplantation in piebaldism patients: A retrospective study

PURPOSE

To compare the efficacy and safety of autologous cultured melanocytes transplantation (CMT) and non-cultured epidermal cell suspension transplantation (NCES) in the treatment of piebaldism.

PATIENTS AND METHODS

A retrospective study was conducted on 30 anatomically based lesions from nine piebaldism patients who underwent either CMT (n = 7) or NCES (n = 23) between 2018 and 2020. The extent of repigmentation and colour matching was evaluated in all recipient sites using a digital imaging analysis system. In addition, adverse effects have also been assessed by follow-up results.

RESULTS

More than 75% repigmentation was achieved in 100% (7/7) and 60.9% (14/23) of the 30 lesions with the CMT and NCES, respectively. There were significant differences between the two methods in terms of repigmentation. The majority of patients had colour mismatches, and there was no discernible difference between the two surgical techniques. Adverse reactions rarely occurred.

CONCLUSION

The present study suggested that autologous CMT may provide better repigmentation in piebaldism patients than NCES with no significant side effects.

Donor to recipient ratios in the surgical treatment of vitiligo and piebaldism: a systematic review

Stabilized vitiligo resistant to conventional therapy (e.g. segmental vitiligo) and piebaldism lesions can be treated with autologous cellular grafting techniques, such as non-cultured cell suspension transplantation (NCST) and cultured melanocyte transplantation (CMT). These methods are preferred when treating larger surface areas due to the small amount of donor skin needed. However, the donor to recipient expansion ratios and outcomes reported in studies with cellular grafting vary widely, and to date, no overview or guideline exists on the optimal ratio. The aim of our study was to obtain an overview of the various expansion ratios used in cellular grafting and to identify whether expansion ratios affect repigmentation and colour match. We performed a systematic literature search in MEDLINE and EMBASE to review clinical studies that reported the expansion ratio and repigmentation after cellular grafting. We included 31 eligible clinical studies with 1591 patients in total. Our study provides an overview of various expansion ratios used in cellular grafting for vitiligo and piebaldism, which varied from 1:1 up to 1:100. We found expansion ratios between 1:1 and 1:10 for studies investigating NCST and from 1:20 to 1:100 in studies evaluating CMT. Pooled analyses of studies with the same expansion ratio and repigmentation thresholds showed that when using the lowest (1:3) expansion ratio, the proportion of lesions achieving >50% or >75% repigmentation after NCST was significantly better than when using the highest (1:10) expansion ratio (χ² P = 0.000 and χ² P = 0.006, respectively). Less than half of our included studies stated the colour match between different expansion ratios, and results were variable. In conclusion, the results of our study indicate that higher expansion ratios lead to lower repigmentation percentages after NCST treatment. This should be taken into consideration while determining which expansion ratio to use for treating a patient.

Efficacy of suction blister epidermal grafting with concomitant phototherapy in vitiligo treatment

Introduction

There are many surgical methods for vitiligo treatment that have been used for over 30 years. Suction blister epidermal grafting (SBEG) is considered one of the simplest and most effective of them.

Aim

To determine how effective suction blister grafts with concomitant phototherapy are in vitiligo treatment.

Material and methods

The study was conducted on 10 patients with vitiligo that was resistant to previous treatment including phototherapy in monotherapy. Involvement of affected sites was different for every patient. We used cryotherapy for blistering at the recipient site and an automatic suction device for blistering at the donor site. The blister was separated from the donor site and fixed with dressing to the recipient site. After removing the final dressing (about 7 days after SBEG) patients started phototherapy (6 patients had UVB 311 nm and 4 had PUVA). All patients treated with UVB 311 nm were qualified for treatment in our clinic and the method was chosen according to expert recommendations from the European Dermatology Forum (EDF) Guidelines for Vitiligo where narrowband (NB) UVB is the phototherapy of choice. Three patients who had PUVA therapy were treated with this method in other clinical centers and sent to us only to undergo SBEG. One patient had previously received UVB 311 nm for 3 months, which showed no effects. Repigmentation of lesions was evaluated at 3 and 6 months after the surgical procedure.

Results

Ten patients (9 females with a mean age of 36.88 years and 1 man aged 39 years) were enrolled in the study. Nine patients showed progressive repigmentation at 3 and 6 months follow-up with a rate varying from 13 to 76% (mean: 44.5%) and 35 to 100% (mean: 67.5%). One patient showed 5% depigmentation at a visit after 6 months in comparison to the follow-up visit 3 months after SBEG.

Conclusions

With this technique, patients who did not respond to the usual treatments showed very good repigmentation over a 6-month follow-up. There were no side effects such as scarring.

Exposure of human melanocytes to UVB twice and subsequent incubation leads to cellular senescence and senescence-associated pigmentation through the prolonged p53 expression

BACKGROUND

Ultraviolet radiation (UVR) is a well-known factor in skin aging and pigmentation, and daily exposure to subcytotoxic doses of UVR might accelerate senescence and senescence-associated phenomena in human melanocytes.

OBJECTIVE

To establish an in vitro melanocyte model to mimic the conditions of repeated exposure to subcytotoxic doses of UVB irradiation and to investigate key factor(s) for melanocyte senescence and senescence-associated phenomena.

METHODS

Human epidermal melanocytes were exposed twice with 20 mJ/cm² UVB over a 24-h interval and subsequently cultivated for 2 weeks. Senescent phenotypes were addressed morphologically, and by measuring the senescence-associated β-galactosidase (SA-β-Gal) activity, cell proliferation capacity with cell cycle analysis, and melanin content.

RESULTS

The established protocol successfully induced melanocyte senescence, and senescent melanocytes accompanied hyperpigmentation. Prolonged expression of p53 was responsible for melanocyte senescence and hyperpigmentation, and treatment with the p53-inhibitor pifithrin-α at 2-weeks post-UVB irradiation, but not at 48 h, significantly reduced melanin content along with decreases in tyrosinase levels.

CONCLUSION

Melanocyte senescence model will be useful for studying the long-term effects of UVB irradiation and pigmentation relevant to physiological photoaging, and screening compounds effective for senescence-associated p53-mediated pigmentation.

Detection of auto antibodies and transplantation of cultured autologous melanocytes for the treatment of vitiligo

The aim of the present study was to establish an immunofluorescence method of antibody detection to identify melanocytes in the serum of vitiligo patients. Furthermore, we aimed to establish a method for the culture and proliferation of autologous pure melanocytes and to observe the effect of their transplantation for the treatment of vitiligo. Suspension of epidermal cells with melanocytes was performed using trypsin digestion of normal epiderm from eyelid operation and melanocytes were selectively cultured and proliferated in serum-free M2 medium. FITC-labeled rabbit anti-human antibody was used to detect the relative fluorescence intensity of the melanocytes. After identification with immunological and biological examinations, the melanocytes were transplanted to depigmented areas of vitiligo. Repigmentation was observed continuously. The results indicated that melanocytes could be selectively proliferated in the medium. Subsequently, pure melanocytes without contamination of fibroblast and keratinocyte were harvested. A total of 34 patients suffering vitiligo for between 3 months and 20 years with depigmented area (between 4 cm² and 70% of body surface) were divided into 19 cases of developing stage and 15 cases of stable stage, according to the change of depigmentation. A total of 15 developing cases were positive for the antibody against melanocytes, with the positive rate of 79%. The titers of serum was >1:50 in 10 patients at the developing stage, and 5 developing patients were 1:10. Among the 15 stable cases, four were positive, with a positive rate of 27%. Fluorescence of antibody was localized in the cytoplasm of the melanocytes. Autologous melanocytes of vitiligo patients could be selectively proliferated in the medium. Next, pure melanocytes without contamination with fibroblasts and keratinocytes were harvested. A total of 16 vitiligo patients with 28 depigmented areas (2–200 cm²) were treated with transplantation of melanocytes. Repigmentation of the transplanted areas appeared as red coloration after one month. All the vitiligous areas received transplantation were repigmented significantly with hypo- or hyper-pigmentation after 3–5 months. After 6–8 months, 87.5% of lesions showed repigmentation of >50% of the lesion area. No scarring or other side-effects occurred. After follow-up of 5 years, no relapse was observed in transplantation area. Thus, an immunofluorescence method for the test of antibody to melanocytes in the serum of vitiligo patients was established. Transplantation of cultured autologous melanocytes was an effective and safe measure for treatment of vitiligo, particularly for patients with a large depigmented area.

Hair follicle melanocyte precursors are awoken by ultraviolet radiation via a cell extrinsic mechanism

Melanocyte stem cells (MCSCs) in the upper portion of the hair follicle periodically supply melanocytes (MCs) that migrate downward into the hair bulb during anagen, the growth phase of the hair cycle. However MCs can also migrate upwards. We previously observed an increase in epidermal MC density in the mouse epidermis after a single ultraviolet radiation (UVR) exposure in neonatal, but not adult mice. To better understand MCSC activation by UVR we methodically studied the response of MCs to narrow band UVB (since UVA does not invoke this response) exposure in neonatal mice, and in adults at different stages of the hair cycle. We found that a single exposure of adult mice did not induce activation of MCSCs, in any stage of the hair cycle. When adult mice MCSCs were isolated in telogen, multiple UVB exposures resulted in their activation and production of daughter cells, which migrated upwards to the epidermis. Importantly, the MCSCs produced new progeny without themselves having incurred DNA damage after UVB exposure. This, together with examination of MC localisation in the skin of mice overexpressing stem cell factor in their keratinocytes, leads us to conclude that MCSC activation by UVB is driven via paracrine production of either SCF and/or other keratinocyte cytokines. We re-examined the increase in epidermal MC density in neonatal mouse skin. This effect was much more profound after only a single exposure than that of even multiple exposures to adult skin, and we show that in this setting also, the epidermal MCs mostly derive from activation of MC precursors in the upper hair follicle, and most likely via a cell extrinsic mechanism. Hence, although adaptive changes in the skin induced by repetitive UVB exposures are necessary in adult mice, in both the adult and neonatal context the division and migration upwards of follicular MCSCs is the major mode by which epidermal MC numbers increase after UVR exposure.

Ribosomal stress, p53 activation and the tanning response

Melanocytes (MC) sit along the epidermal basal layer, largely quiescent except for constitutive melanin production. They are usually only activated after sun exposure. The recent paper by McGowan et al. (1) describes a novel mechanism by which melanocytes are induced to proliferate upon p53 activation in adjacent keratinocytes (KC). In this study, small subunit ribosomal protein mutations cause a dramatic activation of p53 that we propose mimics important aspects of the skin sunburn response after ultraviolet radiation (UVR) exposure. McGowan et al. show that the phenotype of their hyperpigmented mouse mutants results from p53-dependent upregulation of KITLG, a cytokine that binds to the KIT receptor on melanocytes and influences melanin synthesis, melanocyte proliferation, and dictates MC localization at the dermo-epidermal junction. These findings extend our knowledge about skin stress responses, in particular, how p53 activity in keratinocytes is central to the regulation of melanocyte behaviour.

Piebaldism

Piebaldism is an uncommon autosomal dominantly inherited pigment anomaly characterized by a congenital white forelock and leukoderma on the frontal scalp, forehead, ventral trunk and extremities. It is caused by a loss-of-function mutation in the KIT gene. Genetic analyses reveal a consistent genotype-phenotype relationship in piebaldism. However, recently reported cases of piebaldism that are milder or severer than genetically expected indicate that other factors, such as a modifier gene of MC1R, influence skin and hair color. The KIT ligand/KIT that triggers the Ras/mitogen-activated protein kinase signaling pathway play essential functions in the migration, proliferation, survival, melanogenesis and melanosome transfer of the melanocytes. We summarize current research progress in piebaldism and related disorders.

Toward the isolation and culture of melanocyte stem cells

A new level of understanding of pigment cell biology and pathology will require the ability to culture and manipulate melanocyte stem cells (MCSCs) in vitro. In this issue, Nishikawa-Torikai et al. report progress toward this end. MCSCs isolated from mouse hair follicles can be expanded in vitro in a feeder-layer culture system. Application to human systems can be expected.

Cutaneous melanoma: how does ultraviolet light contribute to melanocyte transformation?

Ascribing a causal role to ultraviolet radiation in melanoma induction is problematic, as the relationship between total lifetime sun exposure and melanoma risk is not as strong as for some other skin cancers. Epidemiological studies show that heightened melanoma risk is most associated with intermittent sunburns. Despite this, lesions can develop on anatomical locations receiving intermittent (e.g., the trunk) or chronic exposures (e.g., the head and neck). Individuals developing melanoma on truncal sites tend to have more nevi, suggesting that in addition to the differences in forms of sun exposure, there may also be innate variation that makes one more susceptible to one or other mechanism of melanoma development. Such differences may depend upon different responses at the time of exposure (e.g., pigmentation characteristics, DNA repair capability and melanocyte proliferative response), and/or the role of the skin microenvironment in limiting proliferation of a ‘primed’ or mutated melanocyte during the latent period leading up to the appearance of a melanocytic lesion.

Murine neonatal melanocytes exhibit a heightened proliferative response to ultraviolet radiation and migrate to the epidermal basal layer

Melanocytes respond to UVR not only by producing melanin, but also by proliferating. This is essentially a protective response. We have studied the melanocyte proliferative response after a single UVR exposure to neonatal mice. At 3 days post-UVR in wild-type neonates we observed a marked melanocyte activation not seen in adults. Melanocytes migrated to the epidermal basal layer, their numbers peaking at 3-5 days after UVR then diminishing. They appeared to emanate from the hair follicle, migrating to the epidermis via the outer root sheath. In melanoma-prone mice with melanocyte-specific overexpression of Hras(G12V), basal layer melanocytes were increased in size and dendricity compared to UVR-treated wild-type mice. Melanocytes in mice carrying a pRb pathway cell-cycle defect (oncogenic Cdk4(R24C)) did not show an enhanced response to UVR such as those carrying Hras(G12V). The exquisite sensitivity to UVR-induced proliferation and migration that characterizes neonatal mouse melanocytes may partly explain the utility of this form of exposure for inducing melanoma in mice that carry oncogenic mutations.

Mechanisms of Laser Hair Removal: Could Persistent Photoepilation Induce Vitiligo or Defects in Wound Repair?

BACKGROUND

Current laser hair removal modalities achieve a long-term but not persistent (irreversible) hair loss.

OBJECTIVE

This review highlights the mechanisms of the current laser hair removal technology and explores possible side effects.

METHODS

The literature is reviewed.

RESULTS

The hair shaft plays a key role in the mechanisms underlying current photoepilation procedures by acting as a vector for heat transfer. Together with inherent properties of the hair growth cycle and the anatomic specifics of the follicular stem cells located in the bulge, the crucial role of the hair shaft and its lack of complete destruction with present technology are also likely culprits for the nonpersistent nature of present laser hair removal. Future persistent photoepilation may be associated with vitiligo or vitiligolike changes. Disturbances in wound repair of previously lasered sites are less likely.

CONCLUSIONS

The currently available laser hair removal protocols are safe, not the least because they achieve long-term but not persistent epilation. The adverse effects of persistent laser hair removal technology possibly available in the future are potentially problematic.

Suction blister epidermal grafting for management of eyelid vitiligo: special considerations

BACKGROUND

Suction blister epidermal grafting is an established technique for the treatment of resistant and stable vitiligo especially over small and cosmetically important areas like the face. However, certain areas, such as lips and eyelids, require special considerations because of their anatomic peculiarities.

PATIENTS AND METHODS

The current study was carried out on six patients of stable eyelid vitiligo, not responding to medical treatment. Suction blister was obtained from the thigh using the suction apparatus and the roof was grafted on to the dermabraded eyelid. Certain precautions were taken during the procedure, which will be highlighted in the current study.

RESULTS

Response was excellent in all the patients in 3 to 6 months, with no complications.

CONCLUSIONS

If carried out properly, suction blister technique is the procedure of choice for cosmetically important sites like eyelids.

Development of a Plasma-Polymerized Surface Suitable for the Transplantation of Keratinocyte–Melanocyte Cocultures for Patients with Vitiligo

The purpose of this study was to develop a convenient methodology for the coculture of autologous melanocytes and keratinocytes for grafting of patients with vitiligo. While grafting of pure melanocytes may achieve repigmentation, the inclusion of keratinocytes ensures rapid reepithelialization. Previously we have used confluent sheets of keratinocytes (with melanocytes present) to transfer cells. However, we found that as the keratinocyte density increased, melanocyte number and function were downregulated. Accordingly in this study we explored combinations of three culture surfaces and three media, seeking to achieve subconfluent culture of primary keratinocytes with a reasonable density of melanocytes, using cells immediately after isolation from skin. For this in vitro study, the surfaces studied were uncoated glass coverslips, and glass coverslips coated with collagen I or a nitrogen-containing plasma polymer. The results show that both the substrate surface and the medium composition influence the proliferation and survival of melanocytes. Keratinocytes and melanocytes could be successfully cocultured on a chemically defined plasma polymer substrate using a serum-free medium.