Noncultured extracted hair follicle outer root sheath cell suspension for transplantation in vitiligo

Melanocyte stem cells in the skin: Origin, biological characteristics, homeostatic maintenance and therapeutic potential

Melanocyte stem cells (MSCs), melanocyte lineage-specific skin stem cells derived from the neural crest, are observed in the mammalian hair follicle, the epidermis or the sweat gland. MSCs differentiate into mature melanin-producing melanocytes, which confer skin and hair pigmentation and uphold vital skin functions. In controlling and coordinating the homeostasis, repair and regeneration of skin tissue, MSCs play a vital role. Decreased numbers or impaired functions of MSCs are closely associated with the development and therapy of many skin conditions, such as hair graying, vitiligo, wound healing and melanoma. With the advancement of stem cell technology, the relevant features of MSCs have been further elaborated. In this review, we provide an exhaustive overview of cutaneous MSCs and highlight the latest advances in MSC research. A better understanding of the biological characteristics and micro-environmental regulatory mechanisms of MSCs will help to improve clinical applications in regenerative medicine, skin pigmentation disorders and cancer therapy. KEY POINTS: This review provides a concise summary of the origin, biological characteristics, homeostatic maintenance and therapeutic potential of cutaneous MSCs. The role and potential application value of MSCs in skin pigmentation disorders are discussed. The significance of single-cell RNA sequencing, CRISPR-Cas9 technology and practical models in MSCs research is highlighted.

Lesional CD8+ T-Cell Number Predicts Surgical Outcomes of Melanocyte-Keratinocyte Transplantation Surgery for Vitiligo

The melanocyte-keratinocyte transplantation procedure (MKTP) treats stable and recalcitrant vitiligo. Despite careful selection of candidates based on clinical stability, the success of the procedure is unpredictable. The aim of our study was to define the immunological profile of stable vitiligo lesions undergoing MKTP and correlate them with clinical outcomes. We included 20 MKTP candidates with vitiligo and a patient with piebaldism as a control. Prior to MKTP, T-cell subsets and chemokines in the recipient skin were measured by flow cytometry and ELISA. During MKTP, melanocytes in the donor skin were quantified by flow cytometry. After MKTP, patients were followed for 12 months and repigmentation was assessed clinically and by ImageJ analysis of clinical photographs. Baseline immunologic biomarkers, duration of clinical stability, and transplanted melanocyte number were correlated to postsurgical repigmentation scores. CD8+ T cells were elevated in 43% of the clinically stable vitiligo lesions. CD8+ T-cell number negatively correlated with postsurgical repigmentation scores (r = -0.635, P = 0.002). Duration of clinical stability, skin chemokines, and transplanted melanocyte number did not influence postsurgical repigmentation. This study demonstrates that CD8+ T-cell number correlates negatively with success of postsurgical repigmentation and can be a biomarker to identify ideal surgical candidates.

Vitiligo Treatments: Review of Current Therapeutic Modalities and JAK Inhibitors

Vitiligo is a chronic autoimmune disease characterized by loss of pigment of the skin, affecting 0.5-2% of the population worldwide. It can have a significant impact on patients' quality of life. In recent years, there has been significant progress in our understanding of the pathogenesis of vitiligo. It is believed that vitiligo develops due to a complex combination of genetics, oxidative stress, inflammation, and environmental triggers. Conventional treatments include camouflage, topical corticosteroids, topical calcineurin inhibitors, oral corticosteroids, phototherapy, and surgical procedures, with the treatment regimen dependent on the patient's preferences and characteristics. With increased understanding of the importance of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway in the pathogenesis of vitiligo, treatment has expanded to include the first US FDA-approved cream to repigment patients with vitiligo. This review summarizes our understanding of the major mechanisms involved in the pathogenesis of vitiligo and its most common available treatments.

Current Status of Cell-Based Therapies for Vitiligo

Vitiligo is a chronic pigmentary disease with complex etiology, the signs of which are caused by the destruction of melanocytes in the epidermis, leading to the lack of melanin pigment responsible for skin coloration. The treatment of vitiligo, which aims at repigmentation, depends both on the clinical characteristics of the disease as well as on molecular markers that may predict the response to treatment. The aim of this review is to provide an overview of the clinical evidence for vitiligo cell-based therapies taking into account the required procedures and equipment necessary to carry them out as well as their effectiveness in repigmentation, assessed using the percentage of repigmentation of the treated area. This review was conducted by assessing 55 primary clinical studies published in PubMed and ClinicalTrails.gov between 2000 and 2022. This review concludes that the extent of repigmentation, regardless of the treatment method, is highest in stable localized vitiligo patients. Moreover, therapies that combine more than one cell type, such as melanocytes and keratinocytes, or more than one method of treatment, such as the addition of NV-UVB to another treatment, increase the chances of >90% repigmentation. Lastly, this review concludes that various body parts respond differently to all treatments.

Evaluation of clinical efficacy and laboratory indicators of non-cultured epidermal cell suspension and hair follicle cell suspension in surgical management of stable vitiligo: A randomized comparative trial

BACKGROUND

Non-cultured epidermal cell suspension (ECS) and hair follicle cell suspension (HFCS) are well-established methods of surgical treatment of stable vitiligo.

AIMS

The aim of the present study was to compare the laboratory indicators and clinical efficacy of ECS and HFCS in the treatment of stable vitiligo.

METHODS

This was a single centre, open-labeled randomized trial. Vitiligo patches from 74 patients were randomized to receive either ECS or HFCS. Both cell suspensions were analyzed for total cell count, cell viability and melanocyte count. Percentage re-pigmentation was assessed at regular intervals for 36 weeks.

RESULTS

The percentage re-pigmentation with ECS was significantly higher than HFCS at week 4 (p = .01) and week 16 (p = .03) however, no difference was observed at weeks 24 (p = .38) and 36 (p = .05). Forty-seven patients completed the study follow-up duration and excellent re-pigmentation (>90%) was achieved in 61.7% and 53.2% and complete re-pigmentation (100%) was observed in 6.4% and 12.8% of participants using ECS and HFCS, respectively. Significantly higher cell yield (p < .01) and percentage of HMB45+ melanocytes (p = .01) were obtained using ECS. No difference was noted in the percentage of viable cells or S100 + melanocytes.

CONCLUSION

The median cell yield was eight times higher in ECS than in HFCS with a significantly higher percentage of HMB45+ melanocytes in the former group. The median percentage of re-pigmentation in both groups was 90% at the end of 36 weeks. ECS provides faster re-pigmentation; however, both ECS and HFCS have comparable safety and efficacy over a longer duration of follow-up.

Regenerative Medicine-Based Treatment for Vitiligo: An Overview

Vitiligo is a complex disorder with an important effect on the self-esteem and social life of patients. It is the commonest acquired depigmentation disorder characterized by the development of white macules resulting from the selective loss of epidermal melanocytes. The pathophysiology is complex and involves genetic predisposition, environmental factors, oxidative stress, intrinsic metabolic dysfunctions, and abnormal inflammatory/immune responses. Although several therapeutic options have been proposed to stabilize the disease by stopping the depigmentation process and inducing durable repigmentation, no specific cure has yet been defined, and the long-term persistence of repigmentation is unpredictable. Recently, due to the progressive loss of functional melanocytes associated with failure to spontaneously recover pigmentation, several different cell-based and cell-free regenerative approaches have been suggested to treat vitiligo. This review gives an overview of clinical and preclinical evidence for innovative regenerative approaches for vitiligo patients.

Surgical Treatment of Vitiligo

Vitiligo is described as a dermatological condition characterized by pigmentation disorders in both the skin and mucous membranes. Clinically, this disease is characterized by the presence of well-defined white areas of various shapes and sizes, which are a manifestation of a reduced number of melanocytes. Due to the fact that vitiligo can be a significant cosmetic problem for patients, a number of methods are currently available to help fight for a better skin appearance. If all the available non-invasive procedures turn out to be ineffective, surgery can help, which is a very good alternative in the case of difficult-to-treat but stable changes. Both the development of new techniques and modifications to the already available treatment of cell and tissue transplantation give hope to numerous patients around the world. The effectiveness of a particular method is determined by its appropriate selection depending on the lesions undergoing therapy. Each form of surgical intervention has its advantages and disadvantages, which, along with the location or size of the treated hypopigmentation area, should be analyzed by a doctor and discussed with their patient. This article is an overview of the currently available methods of surgical treatment of vitiligo and a comparison of their pros and cons.

Surgical procedures and innovative approaches for vitiligo regenerative treatment and melanocytorrhagy

Surgical treatments for vitiligo are a safe and effective treatment modality for select patients with vitiligo. Many techniques of vitiligo surgery exist, each with unique advantages and disadvantages. We reviewed the various surgical therapies and innovative approaches for vitiligo regenerative treatment reported in the literature. Surgical therapies can be subdivided into tissue grafting methods and cellular grafting methods. Tissue grafting methods mainly include mini punch grafts, suction blister roof grafts, and hair follicle grafts. Cellular grafting methods include cultured and non-cultured treatments. The efficacy needs to be improved largely due to the poor proliferation and quality of the autologous melanocytes. Rho-associated protein kinase inhibitor enhances primary melanocyte culture proliferation from vitiligo patients to prevent apoptosis. Innovative approaches using stem cell methods could prove invaluable in developing a novel cell therapy for patients suffering from vitiligo. We succeeded in inducing melanin pigmentation in mice skin in vivo using our human induced pluripotent stem cell-derived melanocytes. In addition, we reviewed melanocytorrhagy, detachment and transepidermal loss of melanocytes, and melanocyte-related adhesion molecules. These adhesion molecules include epithelial cadherin, discoidin domain receptor tyrosine kinase 1, glycoprotein non-metastatic melanoma protein B, macrophage migration inhibiting factor, 17β-hydroxysteroid dehydrogenase 1, and E26 transformation-specific 1.

Surgical Interventions for Patients With Vitiligo: A Systematic Review and Meta-analysis

Importance

Surgical interventions are a key part of the therapeutic arsenal, especially in refractory and stable vitiligo. Comparison of treatment outcomes between the different surgical procedures and their respective adverse effects has not been adequately studied.

Objective

To investigate the reported treatment response following different surgical modalities in patients with vitiligo.

Data Sources

A comprehensive search of the MEDLINE, Embase, Web of Science, and Cochrane Library databases from the date of database inception to April 18, 2020, was conducted. The key search terms used were vitiligo, surgery, autologous, transplantation, punch, suction blister, and graft.

Study Selection

Of 1365 studies initially identified, the full texts of 358 articles were assessed for eligibility. A total of 117 studies were identified in which punch grafting (n = 19), thin skin grafting (n = 10), suction blister grafting (n = 29), noncultured epidermal cell suspension (n = 45), follicular cell suspension (n = 9), and cultured epidermal cell suspension (n = 17) were used.

Data Extraction and Synthesis

Three reviewers independently extracted data on study design, patients, intervention characteristics, and outcomes. Random effects meta-analyses using generic inverse-variance weighting were performed.

Main Outcomes and Measures

The primary outcomes were the rates of greater than 90%, 75%, and 50% repigmentation response. These rates were calculated by dividing the number of participants in an individual study who showed the corresponding repigmentation by the total number of participants who completed the study. The secondary outcomes were the factors associated with treatment response to the surgical intervention.

Results

Among the 117 unique studies and 8776 unique patients included in the analysis, rate of repigmentation of greater than 90% for surgical interventions was 52.69% (95% CI, 46.87%-58.50%) and 45.76% (95% CI, 30.67%-60.85%) for punch grafting, 72.08% (95% CI, 54.26%-89.89%) for thin skin grafting, 61.68% (95% CI, 47.44%-75.92%) for suction blister grafting, 47.51% (95% CI, 37.00%-58.03%) for noncultured epidermal cell suspension, 36.24% (95% CI, 18.92%-53.57%) for noncultured follicular cell suspension, and 56.82% (95% CI, 48.93%-64.71%) for cultured epidermal cell suspension. The rate of repigmentation of greater than 50% after any surgical intervention was 81.01% (95% CI, 78.18%-83.84%). In meta-regression analyses, the treatment response was associated with patient age (estimated slope, -1.1418), subtype of vitiligo (estimated slope, 0.3047), and anatomical sites (estimated slope, -0.4050).

Conclusions and Relevance

The findings of this systematic review and meta-analysis suggest that surgical intervention can be an effective option for refractory stable vitiligo. An appropriate procedure should be recommended based on patient age, site and size of the lesion, and costs.

Stem cell therapy in dermatology

Stem cells are precursor cells present in many tissues with ability to differentiate into various types of cells. This interesting property of plasticity can have therapeutic implications and there has been substantial research in this field in last few decades. As a result, stem cell therapy is now used as a therapeutic modality in many conditions, and has made its way in dermatology too. Stem cells can be classified on the basis of their source and differentiating capacity. In skin, they are present in the inter-follicular epidermis, hair follicle, dermis and adipose tissue, which help in maintaining normal skin homeostasis and repair and regeneration during injury. In view of their unique properties, they have been employed in treatment of several dermatoses including systemic sclerosis, systemic lupus erythematosus, scleromyxedema, alopecia, Merkel cell carcinoma, pemphigus vulgaris, psoriasis, wound healing, epidermolysis bullosa and even aesthetic medicine, with variable success. The advent of stem cell therapy has undoubtedly brought us closer to curative treatment of disorders previously considered untreatable. Nevertheless, there are multiple lacunae which need to be addressed including ideal patient selection, timing of intervention, appropriate conditioning regimens, post-intervention care and cost effectiveness. Further research in these aspects would help optimize the results of stem cell therapy.

Surgical interventions for vitiligo

Since nonsurgical treatment of vitiligo is not always successful, surgical interventions are viable options for patients with refractory vitiligo. Surgical treatment is a method in which melanocytes of normal skin are transplanted into vitiligo lesions and provided as a repigmentation source. Such treatments are primarily divided into tissue grafting and cellular grafting, depending on the nature of the graft. Tissue grafting includes split-thickness skin grafting, suction blister grafting, punch grafting, hair follicle transplantation, and smashed-skin grafting. Cellular grafting includes non-cultured epidermal cell suspension transplantation, non-cultured follicular cell suspension transplantation, and cultured epidermal cell suspension transplantation. Among these, suction blister grafting and micro-punch grafting have been widely performed for localized refractory vitiligo, and non-cultured epidermal cell suspension transplantation is adopted as the standard treatment for extensive vitiligo. Research on cultured cellular grafting to treat larger vitiligo areas is also ongoing. Selecting patients with stable vitiligo that has not spread for over 12 months is the most critical factor in the surgical outcome. It is also important to choose an appropriate surgical modality for each patient, and a combination of various procedures often improves the overall outcome. In conclusion, surgical intervention can be an effective and safe option for patients with vitiligo refractory to conventional treatments. Non-cultured epidermal cell suspension transplantation, which was denied by New Health Technology Assessment in Korea, should be approved to benefit patients with refractory vitiligo.

Hair Follicle as a Source of Pigment-Producing Cells for Treatment of Vitiligo: An Alternative to Epidermis?

To discuss the advantages and limitations of hair follicle-derived cell transplantation (FCT) in vitiligo, compared to the epidermal cell transplantation (ECT), and the knowledge gap which is required to be bridged. The papers relevant to the purpose was reviewed. Surgical approaches for treating vitiligo are based on the idea of replenishing lost melanocytes. Skin and hair follicles as the main sources of melanocytes have been applied for this purpose transferring the whole tissue or tissue-derived cell suspension to the vitiligo lesions. Considering the differences between hair follicle and epidermis in terms of the constituting cell populations, phenotype and function of melanocytes, and micro-environmental factors, different response of vitiligo patients to treatment with FCT or ECT would be expected theoretically. However, there is currently a lack of evidence on such a difference. However, ECT appears to be a more feasible, less time-consuming, and more comfortable treatment for both physicians and patients. Although the current evidence has not shown a significant difference between ECT and FCT in terms of efficacy, ECT appears to be more feasible specifically in the treatment of large lesions. However, further randomized controlled clinical trials with larger sample sizes and longer follow-up durations are required to be conducted to draw a definite conclusion on comparing FCT with ECT in terms of the safety, efficacy, durability of the therapeutic effects, and indications in vitiligo patients.

Comparison of efficacy of noncultured hair follicle cell suspension and noncultured epidermal cell suspension in repigmentation of leukotrichia and skin patch in vitiligo: a randomized trial

BACKGROUND

Vitiligo manifests as hypo- to de-pigmented macules, which are sometimes associated with leukotrichia. For complete cosmetic improvement, the repigmentation of leukotrichia is an important component.

METHODS

This randomized controlled trial included patients with stable vitiligo with leukotrichia. Two vitiligo patches in each patient were randomized to receive either of the two procedures. The patients were followed up for 9 months posttransplantation. The efficacy of hair follicle cell suspension (HFCS) with epidermal cell suspension (ECS) in repigmentation of leukotrichia and skin in vitiligo was compared.

RESULTS

A total of 20 patients underwent the procedure, and 19 completed the follow-up. The area of the vitiligo patch and the number of leukotrichia in the patches were comparable between the two groups. There was a significant difference in the mean ± S.D. number of cells transplanted between the two groups (5.06 × 10⁵ in HFCS vs. 39.8 × 10⁵ in ECS, P < 0.0001). The percentage viability of cells and proportion of melanocytes were comparable between the two groups. A total of 10 patients in HFCS and eight patients in ECS had repigmentation of leukotrichia. The mean ± S.D. percentages of depigmented hair showing repigmentation at nine months were 7.42 ± 11.62% in HFCS and 11.42 ± 17.90% in ECS (P = 0.4195), whereas the mean ± S.D. percentage repigmentation of vitiligo patches was 61.58 ± 42.68% in HFCS and 78.68 ± 30.03% in ECS (P = 0.1618).

CONCLUSIONS

The mean number of cells transplanted in the HFCS group was about eight times less than those in ECS. ECS was better than HFCS in repigmentation of leukotrichia and vitiligo, although the difference was not statistically significant.

BMP4-Induced Differentiation of Human Hair Follicle Neural Crest Stem Cells into Precursor Melanocytes from Hair Follicle Bulge

Background

Vitiligo is a skin depigmentation disorder, for which, repigmentation treatment with combined follicular unit extraction (FUE) graft and narrowband ultraviolet B (NBUVB) is considered superior to micro-punch graft therapy. BMP4 can induce MITF expression in Neural crest stem cells (NCSCs), and α-MSH subsequently promotes the differentiation of MITF-expressing cells along the melanocyte lineage.

Objective

To investigate why FUE grafting is superior to epidermal mini grafting in promoting hair follicles (HF) melanocyte cell survival and longevity, we planned the in vitro experiments HF bulge NCSCs differentiate into melanocyte precursors under the co-treatment of BMP4 and α-MSH.

Methods

Cells that migrated from the HF bulge of scalp were cultured and assessed using immunofluorescence. Transcriptome analysis was performed on RNA sequencing results.

Results

Basic fibroblast growth factor promotes the proliferation and survival of NCSCs, with spontaneous differentiation into SOX10+/SOX2+ glial progenitors, but not into SOX10+/MITF+ precursor melanocytes. Both BMP4 and α-MSH promoted the differentiation into MITF-expressing cells. RNA sequencing revealed a downregulation in neuregulin-1 (NRG1) and sermaphorin 3C (SEMA3C), and upregulation in WNT10A. Furthermore, FUE grafting had a source of reservoir melanocytes superior to mini- grafting in treatment for vitiligo.

Conclusion

We obtained SOX10+/MITF+ precursor melanocytes through an induction of differentiation along the melanocyte lineage by BMP4 and α-MSH. According to the RNA sequencing results that NRG1 and SEMA3C were downregulated and WNT10A was upregulated, we postulated that HF NCSCs differentiated into melanocyte by co-treatment of BMP4 and α-MSH. Overall, FUE grafting is a more robust and substitutive treatment option for vitiligo.

Factors affecting the outcome of the suction blisters using two different harvesting techniques in vitiligo patients

BACKGROUND

Suction blister grafting (SBG) technique has been used for long to treat various skin conditions. Different suction methods have been used such as syringes, Chinese cups, and suction device. There are some limitations of its use as time consumption, failure of induction or incomplete blister formation and pain.

AIM

The aim of this work was to evaluate the outcome of using two different suction techniques, namely the syringes and the Chinese cups in induction of suction blisters. The effect of the device diameter and preheating of the donor area on the suction blister induction time (SBIT) was studied. The effect of saline injection in the blister formation and its completion was also evaluated.

METHODS

The study was a left-right comparative study that included 50 patients with stable nonsegmental vitiligo. They were classified into four groups: Group 1 included 15 patients where different diameters of syringes (1.3, 1.7, and 2 cm) were compared against each other, group 2 included 15 patients where different diameters of cups (2, 3.5, and 5 cm) were compared against each other, group 3 included 20 patients subdivided into two groups; 10 patients each, where the effect of preheating the skin on blister induction was tested with use of cups (3a) and syringes (3b). Lastly, group 4 included randomly chosen 40 incomplete or multilocular blisters where the effect of saline injection on blister completion and coalescence of multilobulation was examined. SBIT was calculated in all patients.

RESULTS

The use of the small diameter syringes or cups gave shorter SBIT; however, the difference, which was significant between all sizes of cups, was significant between the 1.3- and 2-cm-diameter syringes only. Preheating of the donor area shorten SBIT significantly. No complications were reported at the donor site except for transient postinflammatory hyperpigmentation in all patients.

CONCLUSION

The small diameter syringes or cups and preheating of the donor area shorten the SBIT, while intra-blister saline injection increased the blister size and turns the multilocular blisters to unilocular ones.

Efficacy of Transplantation of Combination of Noncultured Dermal and Epidermal Cell Suspension vs Epidermal Cell Suspension Alone in Vitiligo: A Randomized Clinical Trial

Importance

Surgical interventions, notably noncultured epidermal suspension (NCES), are the next line of treatment in patients with vitiligo who fail to respond to medical therapy. Noncultured epidermal suspension is usually performed in patients with vitiligo with duration of clinical stability (DS) of 12 months or longer because DS is a vital parameter in determining outcome of NCES. In this pilot study, we planned to assess the efficacy of a novel combination of noncultured epidermal cell suspension and noncultured dermal cell suspension (NCES and NDCS) in patients with vitiligo with shorter DS (3-6 months).

Objective

To compare the efficacy of transplantation of NCES and NDCS vs NCES alone in patients with vitiligo with DS of 3 to 6 months.

Design, Setting, and Participants

A single-center randomized clinical trial including 40 patients with focal, segmental, or generalized vitiligo with DS of 3 to 6 months or more than 12 months was carried out. Based on DS, 2 groups including 20 patients each were recruited (DS in group 1, 3 to 6 months; DS in group 2, more than 12 months). Each group was further randomized into 2 subgroups, A and B.

Intervention

Patients in subgroups 1A and 2A underwent NCES alone, whereas patients in subgroups 1B and 2B underwent NCES and NDCS.

Main Outcomes and Measures

Extent of repigmentation, color match, and pattern of repigmentation at 24 weeks.

Results

Of the 40 study participants, mean (SD) age was 24.9 (4.0) years and 24 (60%) were women; in group 1 with DS for 3 to 6 months, more than 75% repigmentation at 24 weeks was observed in all 10 patients in subgroup 1B (NCES and NDCS) compared with 3 of 10 patients in subgroup 1A (NCES) (100% vs 30%, P = .003). In group 2 (DS > 12 months), the same was observed in 6 of 10 patients in subgroup 2A and 7 of 10 patients in subgroup 2B (NCES) (60% vs 70%, P > .99). The 2 groups and subgroups did not show any significant differences with respect to color matching and pattern of repigmentation.

Conclusions and Relevance

Combination of NCES and NDCS resulted in excellent response in patients with vitiligo with shorter duration of clinical stability compared with NCES alone. This combination may be used early in the course of stable vitiligo without waiting for a period of 12 months or more since last clinical activity.

Trial Registration

ClinicalTrials.gov identifier: NCT03013049.

Functional Skin Grafts: Where Biomaterials Meet Stem Cells

Skin tissue engineering has attained several clinical milestones making remarkable progress over the past decades. Skin is inhabited by a plethora of cells spatiotemporally arranged in a 3-dimensional (3D) matrix, creating a complex microenvironment of cell-matrix interactions. This complexity makes it difficult to mimic the native skin structure using conventional tissue engineering approaches. With the advent of newer fabrication strategies, the field is evolving rapidly. However, there is still a long way before an artificial skin substitute can fully mimic the functions and anatomical hierarchy of native human skin. The current focus of skin tissue engineers is primarily to develop a 3D construct that maintains the functionality of cultured cells in a guided manner over a period of time. While several natural and synthetic biopolymers have been translated, only partial clinical success is attained so far. Key challenges include the hierarchical complexity of skin anatomy; compositional mismatch in terms of material properties (stiffness, roughness, wettability) and degradation rate; biological complications like varied cell numbers, cell types, matrix gradients in each layer, varied immune responses, and varied methods of fabrication. In addition, with newer biomaterials being adopted for fabricating patient-specific skin substitutes, issues related to escalating processing costs, scalability, and stability of the constructs under in vivo conditions have raised some concerns. This review provides an overview of the field of skin regenerative medicine, existing clinical therapies, and limitations of the current techniques. We have further elaborated on the upcoming tissue engineering strategies that may serve as promising alternatives for generating functional skin substitutes, the pros and cons associated with each technique, and scope of their translational potential in the treatment of chronic skin ailments.

Combination of Follicular and Epidermal Cell Suspension as a Novel Surgical Approach in Difficult-to-Treat Vitiligo: A Randomized Clinical Trial

Importance

Epidermal cell suspension (ECS) and follicular cell suspension (FCS) are successful surgical modalities for the treatment of stable vitiligo. However, repigmentation in generalized and acrofacial vitiligo and over acral or bony sites (eg, elbows, knees, iliac crests, and malleoli), which are difficult to treat, is challenging.

Objective

To study the efficacy of transplanting a combination of autologous, noncultured ECS and FCS (ECS + FCS) compared with ECS alone in stable vitiligo.

Design, Setting, and Participants

A prospective, observer-blinded, active-controlled, randomized clinical trial was conducted at a tertiary care hospital, with treatment administered as an outpatient procedure. Thirty participants who had stable vitiligo with symmetrical lesions were recruited between October 18, 2013, and October 28, 2016. All of the lesions were resistant to medical modalities with minimum lesional stability of 1 year. Intent-to-treat analysis was used.

Interventions

ECS + FCS was prepared by mixing equal amounts (in cell number) of FCS with ECS. After manual dermabrasion, ECS was applied to 1 lesion and ECS + FCS was applied to the anatomically based paired lesion of the same patient. No adjuvant treatment was given.

Main Outcomes and Measures

Patients were followed up at 4, 8, and 16 weeks by a blinded observer and extent of repigmentation, color match, pattern of repigmentation, patient satisfaction and complications were noted. Both the visual and the computerized image analysis methods were used for outcome assessment. Cell suspensions were assessed post hoc for OCT4+ stem cell counts using flow cytometry; expression of stem cell factor and basic fibroblast growth factor was evaluated using quantitative relative messenger RNA expression.

Results

Of the 30 patients included in the study, 18 (60%) were women; mean (SD) age was 23.4 (6.4) years. Seventy-four percent of the lesions (62 of 84) were difficult-to-treat vitiligo. ECS + FCS showed superior repigmentation outcomes compared with ECS: extent (76% vs 57%, P < .001), rapidity (48% vs 31%, P = .001), color match (73% vs 61%, P < .001), and patient satisfaction (mean [SD] patient global assessment score, 23.30 [6.89] vs 20.81 [6.61], P = .047). Melanocyte stem cell counts (2% in ECS + FCS vs 0.5% in ECS) as well as expression of basic fibroblast growth factor (11.8-fold) and stem cell factor (6.0-fold) were higher in ECS + FCS suspension (P<.05 for both).

Conclusions and Relevance

The findings from this study establish ECS + FCS as a novel approach in vitiligo surgery for attaining good to excellent repigmentation in a short period with good color match, even in difficult-to-treat vitiligo.

Trial Registration

ctri.nic.in Identifier: CTRI/2017/05/008692.

Melanocyte Chitosan/Gelatin Composite Fabrication with Human Outer Root Sheath-Derived Cells to Produce Pigment

The hair follicle serves as a melanocyte reservoir for both hair and skin pigmentation. Melanocyte stem cells (MelSCs) and melanocyte progenitors reside in the bulge/sub-bulge region of the lower permanent portion of the hair follicle and play a vital role for repigmentation in vitiligo. It would be beneficial to isolate MelSCs in order to further study their function in pigmentary disorders; however, due to the lack of specific molecular surface markers, this has not yet been successfully accomplished in human hair follicles (HuHF). One potential method for MelSCs isolation is the “side population” technique, which is frequently used to isolate hematopoietic and tumor stem cells. In the present study, we decided to isolate HuHF MelSCs using “side population” to investigate their melanotic function. By analyzing mRNA expression of TYR, SOX10, and MITF, melanosome structure, and immunofluorescence with melanocyte-specific markers, we revealed that the SP-fraction contained MelSCs with an admixture of differentiated melanocytes. Furthermore, our in vivo studies indicated that differentiated SP-fraction cells, when fabricated into a cell-chitosan/gelatin composite, could transiently repopulate immunologically compromised mice skin to regain pigmentation. In summary, the SP technique is capable of isolating HuHF MelSCs that can potentially be used to repopulate skin for pigmentation.

Noncultured Extracted Hair Follicle Outer Root Sheath Cell Suspension versus Noncultured Epidermal Cell Suspension in the Treatment of Stable Vitiligo

Background:

Various treatment modalities exist for vitiligo, yet none of them are curative. Vitiligo is still considered a challenging disease to manage. Surgical treatment offers an excellent option for patients with stable vitiligo, especially those who fail to respond to medical treatment. Cell suspension techniques carry the advantage of covering large surface areas.

Objective:

To compare noncultured extracted hair follicle outer root sheath cell suspension (NCORSHFS) and noncultured epidermal cell suspension (NCES) in producing repigmentation.

Subjects and Methods:

Twenty patients were randomly allocated into two groups. They were objectively evaluated for the extent of repigmentation (after 1, 2, and 3 months), complications, cosmetic outcome, and satisfaction.

Results:

In NCORSHFS group, 10% showed excellent pigmentation, 20% showed good pigmentation, 50% fair, and 20% poor pigmentation. In NCES group, 10% showed excellent pigmentation, 10% good pigmentation, 40% fair, and 40% poor pigmentation. This difference was not statistically significant. Excellent color match was observed in 80% of NCORSHFS and in 70% of NCES. Donor area complications were absent in NCORSHFS group, whereas in NCES, mild scarring in 20% and hyperpigmentation in 40% of patients was observed. The difference in patients’ satisfaction between the two groups was not statistically significant.

Conclusion:

Both NCORSHFS and NCES are effective in producing good repigmentation with perfect color match and patients’ satisfaction. NCORSHFS has no donor area complications because it is a scarless procedure.

Vitiligo surgery: A journey from tissues via cells to the stems!

Depigmented patches in vitiligo, a common dermatosis, cause a great psychological distress to the patients. Hence, apart from halting the disease process, the strategies to impart normal skin colour to these white patches carry an important role in the management of vitiligo. Surgical procedures are often required for stable vitiligo lesions not responding to medical therapies. It involves "shuffling" of melanocytes from the pigmented skin to the depigmented areas. During the last fifty years, the vitiligo surgery has evolved from tissue transplantation via cellular transplantation to reach a stage where the use of stem cells or immunomodulatory cells is contemplating. We would like to depict this wonderful journey of vitiligo surgery through this viewpoint.

Autologous non-cultured melanocyte-keratinocyte transplantation in the treatment of vitiligo: patient selection and perspectives

Autologous non-cultured melanocyte–keratinocyte transplantation procedure (MKTP) is one of the simplest cellular grafting techniques. Various modifications were done over the years to make the technique easier and more economical which led to its great popularity among dermatologists. Proper patient selection and good technical skills are essential for achieving success with this technique. In this review, different patient-related and procedure-related factors that affect the outcome are discussed. This review may guide dermatologists to select suitable candidates, and explains what to expect in each case and indicates different techniques which can be used. The expected complications and stability of acquired pigmentation, which are an essential part of the pretreatment patient counseling, are also discussed.

Pheomelanin molecular vibration is associated with mitochondrial ROS production in melanocytes and systemic oxidative stress and damage

Vibrations in covalent bonds affect electron delocalization within molecules, as reported in polymers. If synthesized by living cells, the electron delocalization of polymers affects the stabilization of cellular free radicals, but biomolecular vibration has never been considered a potential source of cytotoxicity. Here we show that the vibrational characteristics of natural pheomelanin and eumelanin contribute to feather color expression in four poultry breeds with different melanin-based pigmentation patterns, but only the vibrational characteristics of pheomelanin are related to the production of reactive oxygen species (ROS) in the mitochondria of melanocytes and to systemic levels of cellular oxidative stress and damage. This association may be explained by the close physical contact existing between mitochondria and melanosomes, and reveals an unprecedented factor affecting the viability of organisms through their pigmentation. These findings open a new avenue for understanding the mechanism linking pheomelanin synthesis to human melanoma risk.

Study of efficacy and safety of noncultured, extracted follicular outer root sheath cell suspension transplantation in the management of stable vitiligo

BACKGROUND

Noncultured, extracted follicular outer root sheath suspension (NC-EHF-ORS-CS) is a recently introduced technique for the treatment of stable vitiligo.

OBJECTIVE

To study the clinical efficacy of this technique and to determine the viability and cell composition of the suspension.

METHODS

Twenty-five patients with stable vitiligo were included in this prospective study. Fifty follicles were extracted from occipital scalp and were incubated with trypsin-ethylenediaminetetraacetic acid to separate outer root sheath cells. The cell suspension was filtered and centrifuged to obtain a cell pellet, which was resuspended and applied to the dermabraded recipient area. Cell viability of the suspension was assessed using trypan blue staining, and markers of keratinocyte stem cells (CD200) and melanocytes (S100) were evaluated using flow cytometry and immunocytochemistry, respectively.

RESULTS

At 6 months, the mean (±SD) repigmentation was 52 ± 25.1%, and >75% repigmentation was seen in 8/25 (32%) patients. Mean percentage cell viability of the suspension was 80 ± 17.2% with a mean concentration of CD200 + and S100 + cells being 7.91 ± 8.68% and 9.93 ± 1.22% (n = 3), respectively. Recipient site infection was seen in 4 of 25 (16%) patients and a color mismatch in 11 of 25 (44%) patients.

CONCLUSION

NC-EHF-ORS-CS is a useful minimally invasive therapy for vitiligo.

Hair & skin derived progenitor cells: In search of a candidate cell for regenerative medicine

BACKGROUND & OBJECTIVES

Skin is an established tissue source for cell based therapy. The hair follicle has been introduced later as a tissue source for cell based therapy. The ease of tissue harvest and multipotent nature of the resident stem cells in skin and hair follicle has promoted basic and clinical research in this area. This study was conducted to evaluate skin stem cells (SSCs) and hair follicle stem cells (HFSCs) as candidate cells appropriate for neuronal and melanocyte lineage differentiation.

METHODS

In this study, SSCs and hair follicle stem cells (HFSCs) were expanded in vitro by explant culture method and were compared in terms of proliferative potential and stemness; differentiation potential into melanocytes and neuronal lineage.

RESULTS

SSCs were found to be more proliferative in comparison to HFSCs, however, telomerase activity was more in HFSCs in comparison to SSCs. Capacity to differentiate into two lineages of ectoderm origin (neuronal and melanocyte) was found to be different. HFSCs cells showed more propensities towards melanocyte lineage, whereas SSCs were more inclined towards neuronal lineage.

INTERPRETATION & CONCLUSIONS

The study showed that SSCs had differential advantage over the HFSCs for neuronal cell differentiation, whereas, the HFSCs were better source for melanocytic differentiation.

Adaptive downregulation of pheomelanin-related Slc7a11 gene expression by environmentally induced oxidative stress

Pheomelanin is a sulphur-containing yellow-to-reddish pigment whose synthesis consumes the main intracellular antioxidant (glutathione; GSH) and its precursor cysteine. Cysteine used for pheomelanogenesis cannot be used for antioxidant protection. We tested whether the expression of Slc7a11, the gene regulating the transport of cysteine to melanocytes for pheomelanogenesis, is environmentally influenced when cysteine/GSH are most required for antioxidant protection. We found that zebra finches Taeniopygia guttata developing pheomelanin-pigmented feathers during a 12-day exposure to the pro-oxidant diquat dibromide downregulated the expression of Slc7a11 in feather melanocytes, but not the expression of other genes that affect pheomelanogenesis by mechanisms different from cysteine transport such as MC1R and Slc45a2. Accordingly, diquat-treated birds did not suffer increased oxidative stress. This indicates that some animals have evolved an adaptive epigenetic lability that avoids damage derived from pheomelanogenesis. This mechanism should be explored in human Slc7a11 to help combat some cancer types related to cysteine consumption.

A Study of Noncultured Extracted Hair Follicle Outer Root Sheath Cell Suspension for Transplantation in Vitiligo

Context:

Vitiligo surgeries have come a long way from tissue grafts to cultured and non cultured cell transplantation. Extracted hair follicle outer root sheath cell transplantation (EHF ORS) suspension is more enriched with melanocyte. In a hair bulb, there is one melanocyte for every five keratinocytes which is much higher than the epidermal melanin unit.

Aims:

To analyse the effectiveness of cultured EHF ORS and to perform objective evaluation based on clinical improvement & photographic evidence. To observe any untoward events or side effects.

Settings and Design:

The study was open and uncontrolled. All the patients were screened at preliminary visit. Reviews were done every two weeks. The endpoint selected was six months post procedure.

Materials and Methods:

Twenty five patients of stable Vitiligo were included in the study and follicular unit were harvested by Follicular Unit Extraction method. Outer root sheath cells were extracted by trypsinization. The solution was transplanted over dermabraded recipient site. Pressure dressing was given. Patients were followed up regularly.

Statistical Analysis Used:

Descriptive Statistics, Chi-Square.

Results:

Mean ± SD repigmentation was 80.15% ± 22.9% with excellent repigmentation (90-100%) in 60% of patients.

Conclusions:

This method is safe, effective, and simpler than the other methods involving cell culturing and requiring a laboratory set-up but selection of patients is crucial for the success of the outcome.

Comparative Study of Efficacy of Epidermal Melanocyte Transfer Versus Hair Follicular Melanocyte Transfer in Stable Vitiligo

Background:

Vitiligo surgery has come up a long way from punch skin grafts to epidermal cell suspension and latest to the extracted hair follicle outer root sheath cell suspension (EHFORSCS) transplantation. The progressive development from one technique to the other is always on a quest for the best. In the latest development, EHFORSCS, which is an enriched source of follicular inactive melanocyte (melanocyte stem cells), seems to be a good addition to the prevailing cell-based therapies for vitiligo. However, it needs to be explored further in larger, clinical trials.

Methodology:

A total of 11 patients with sixty stable vitiligo sites attending dermatology outpatient department were included for the open-labeled, prospective, comparative study. The sites were sequentially distributed into two groups of thirty each. Sites of one group were subjected to epidermal melanocyte transfer (EMT) and the others to hair follicular melanocyte transfer (HFMT). Response to treatment was evaluated on the basis of degree of repigmentation; final evaluation of area of involvement was done after completion of 6 months.

Results:

At the end of 6 months, repigmentation >90% was observed in 83.33% patches of EMT group and 43.33% in HFMT group. Repigmentation >75% was observed in 90% of patches in Group A and 43.34% of patches in Group B, respectively. There was statistically significant difference in the overall pigmentation between these two groups.

Conclusion:

Both noncultured autologous epidermal cell suspension transfer and noncultured EHFORSCS transfer are safe and effective surgical modalities in the management of stable vitiligo though EMT has shown a better response in the present study. Outer root sheath cell suspension transfer is a novel, minimally invasive technique in its nascent stage in the surgical management of vitiligo which requires further larger clinical trials for evaluation of its efficacy.

Melanocyte stem cells as potential therapeutics in skin disorders

INTRODUCTION

Melanocytes produce pigment granules that color both skin and hair. In the hair follicles melanocytes are derived from stem cells (MelSCs) that are present in hair bulges or sub-bulge regions and function as melanocyte reservoirs. Quiescence, maintenance, activation and proliferation of MelSCs are controlled by specific activities in the microenvironment that can influence the differentiation and regeneration of melanocytes. Therefore, understanding MelSCs and their niche may lead to use of MelSCs in new treatments for various pigmentation disorders.

AREAS COVERED

We describe here pathophysiological mechanisms by which melanocyte defects lead to skin pigmentation disorders such as vitiligo and hair graying. The development, migration and proliferation of melanocytes and factors involved in the survival, maintenance and regeneration of MelSCs are reviewed with regard to the biological roles and potential therapeutic applications in skin pigmentation diseases.

EXPERT OPINION

MelSC biology and niche factors have been studied mainly in murine experimental models. Human MelSC markers or methods to isolate them are much less well understood. Identification, isolation and culturing of human MelSCs would represent a major step toward new biological therapeutic options for patients with recalcitrant pigmentary disorders or hair graying. By modulating the niche factors for MelSCs, it may one day be possible to control skin pigmentary disorders and prevent or reverse hair graying.

Potential of regenerative medicine for treatment of vitiligo patients

The article presents a review of publishes sources on the efficacy of methods such as tissue engineering and cellular transplantation of autologous melanocytes for treatment of vitiligo patients. The article describes general principles of treatment and particular features of current melanocyte transplantation methods.

Stem Cell Niche is Partially Lost during Follicular Plucking: A Preliminary Pilot Study

Background:

Clinical hair transplant studies have revealed that follicular unit extraction (FUE) is superior in terms of stable hair growth in comparison to follicular plucking (FP). Various reasons have been cited for this clinical outcome. FUE and FP are employed to obtain the hair follicle units for hair transplant and recently for cell based therapies in vitiligo. However, there is no scientific data available on the comparison of stem cell fraction in the cell suspension obtained by FUE and FP. Therefore, we undertook this study to compare the percentage of stem cells in the hair follicle obtained by FUE and FP.

Objective:

The purpose of the following study is to evaluate the quantitative stem cell pool in the hair follicle obtained by FUE and FP.

Materials and Methods:

A total of 3 human subjects were enrolled with age groups of 17-25 years. Both methods of tissue harvest: FUE and FP; were employed on each subject. There was no vitiligo lesion on the scalp in any of the patients. Hair follicles were incubated with trypsin-EDTA solution at 37°C for 90 min to separate outer root sheath cells. The cell suspension was passed through a 70 μm cell strainer; filtrate was centrifuged to obtain the cell pellet. Cells were labeled with cluster of differentiation (CD200) antibody and acquired with flowcytometry.

Results:

The mean percentage of CD200 positive cells in FUE and FP method come out to be 8.43 and 1.63 respectively (P = 0.0152).

Conclusion:

FUE is a better method of the hair follicle harvesting for cell based applications as the stem cell fraction is significantly higher in comparison to FP.

Extracted hair follicle outer root sheath cell suspension for pigment cell restoration in vitiligo

Vitiligo surgery has come up a long way from punch skin grafts to epidermal cell suspension and latest to the extracted hair follicle outer root sheath cell suspension (EHF-ORS-CS) transplantation. The progressive development from one technique to the other is always in a quest for the best. In the latest development- EHF-ORS-CS, which is an enriched source of follicular inactive melanocyte (melanocyte stem cells), seems to be a good addition to the prevailing cell-based therapies for vitiligo; however, need to be explored further in larger, and preferably randomized blinded studies. This review discusses the principle, technical details, and stem cell composition of hair follicular outer root sheath cell suspension.

Depletion of CD200+ Hair Follicle Stem Cells in Human Prematurely Gray Hair Follicles

Introduction:

Melanocyte stem cells (MelSCs) are known to be depleted in gray hair follicles. Hair follicle stem cells (HFSCs) are important for maintenance of stemness of MelSCs.

Methods:

We compared the proportion of CD200+ (Cluster of Differentiation 200 positive) stem cells in the outer root sheath cell suspension of gray and pigmented hair follicles of three patients with the premature graying of hair. In addition, explants culture for HFSCs was also carried out from gray and pigmented hair follicles. Cultured HFSCs were also differentiated into melanocytes.

Results:

The mean ± SD CD200+ HFSCs population were 9.4 ± 1.4% and 3.5 ± 0.5% for pigmented and gray hair follicles, respectively (P = 0.002). In explants culture, the growth of HFSCs from the gray hair follicle stopped at around day 20–22, whereas the growth of the cells from the pigmented follicle continued.

Conclusion:

CD200+ HFSCs are depleted in prematurely gray hair in the humans. CD200+ hair follicle stem cell yield is poorer in gray hair explant culture than pigmented hair explant culture.

Body hair transplantation in vitiligo

Hair transplantation has been used to repigment a stable vitiligo patch. Body hair transplant was done for a 28-year-old male with stable vitiligo with scarring. Peri-folllicular repigmentation was noted at 4 weeks and complete repigmentation of vitiligo patch was achieved at 12 weeks. No recurrence was noted at the end of 3-month follow-up with a good colour match with surrounding skin. To the best of our knowledge, this is the first case report highlighting the effectiveness of body hair transplantation by FUE in focal vitiligo patch with leukotrichia.

Study of clinical, biochemical and immunological factors determining stability of disease in patients with generalized vitiligo undergoing melanocyte transplantation

BACKGROUND

Stability is considered the most important parameter before performing any melanocyte transplantation procedure in vitiligo; however, current criteria rely on the history given by the patients.

OBJECTIVE

This study was undertaken to determine the clinical, biochemical and immunological factors determining stability of disease in patients with generalized vitiligo to facilitate better patient selection for melanocyte transplantation and to understand immunological mechanisms for disease activity.

METHODS

Thirty-three patients with generalized vitiligo with < 10% body surface area involved were allocated to three clinical stability groups: Group 1 (stability > 3 months but < 1 year), Group 2 (≥ 1 year but < 2 years) and Group 3 (≥ 2 years). Melanocyte transplantation was done using suction blister epidermal grafting (SBEG) on a single patch. Blood was drawn for catalase estimation from all patients and from 10 healthy control subjects. A 3-mm punch biopsy was taken on the day of transplantation from the margin of the macule in the first five patients in each group for the immunohistochemistry of CD4, CD8, CD45RO, CD45RA and FoxP3. Those with ≥ 75% repigmentation at 6 months were labelled as responders.

RESULTS

The success rate was 0% in Group 1, 37·5% in Group 2 and 77·8% in Group 3. The difference in the success rate between the groups was statistically significant (P = 0·005). The median period of stability was significantly higher in the responders compared with that in the nonresponders (P = 0·001). Catalase levels were not significantly different between patients in the three groups of cases and in controls, or between responders and nonresponders. Lesional CD8 cells were significantly higher in Group 1 compared with Group 3. The percentages of CD8 and CD45RO cells were significantly higher in the nonresponders compared with the responders.

CONCLUSION

Along with clinical stability, the proportion of CD8 and CD45RO cells in skin biopsies might help to determine the stability of the disease and thereby predict the success of transplantation.