The Medical Treatment of Vitiligo: An Historical Review

Therapeutic potential and pharmacological mechanism of visnagin

Visnagin is a furanochromone and one of the most important compound in the Ammi visnaga (L.) Lam (a synonym of Visnaga daucoides Gaertn.) plant, which is used to cure various ailments. Many investigations into the bioactive properties of visnagin have been studied to date. The literature on visnagin demonstrates its biological properties, including anti-inflammatory, anti-diabetic, and beneficial effects in cardiovascular and renal diseases. Moreover, visnagin improves sperm quality parameters, stimulates steroidogenesis, and increases serum gonadotropins and testosterone levels, while decreasing pro-inflammatory cytokines, oxidative damage, genomic instability, and it modulates apoptosis. Thus, visnagin has emerged as an exciting lead for further research, owing to its potential in various unmet clinical needs. The current review summarized its basic structure, pharmacokinetics, and pharmacological effects, focusing on its mechanisms of action. The review will help to understand the potential of visnagin as an alternative treatment strategy for several diseases and provide insight into research topics that need further exploration for visnagin's safe clinical use. Please cite this article as: Yadav P, Singh SK, Datta S, Verma S, Verma A, Rakshit A, Bali A, Bhatti JS, Khurana A, Navik U. Therapeutic potential and pharmacological mechanism of visnagin. J Integr Med. 2024; 22(4): 399-412.

Fraxinol Stimulates Melanogenesis in B16F10 Mouse Melanoma Cells through CREB/MITF Signaling

Melanin pigment produced in melanocytes plays a protective role against ultraviolet radiation. Selective destruction of melanocytes causes chronic depigmentation conditions such as vitiligo, for which there are very few specific medical treatments. Here, we found that fraxinol, a natural coumarin from Fraxinus plants, effectively stimulated melanogenesis. Treatment of B16-F10 cells with fraxinol increased the melanin content and tyrosinase activity in a concentration-dependent manner without causing cytotoxicity. Additionally, fraxinol enhanced the mRNA expression of melanogenic enzymes such as tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2. Fraxinol also increased the expression of microphthalmia-associated transcription factor at both mRNA and protein levels. Fraxinol upregulated the phosphorylation of cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB). Furthermore, H89, a cAMP-dependent protein kinase A inhibitor, decreased fraxinol-induced CREB phosphorylation and microphthalmia-associated transcription factor expression and significantly attenuated the fraxinol-induced melanin content and intracellular tyrosinase activity. These results suggest that fraxinol enhances melanogenesis via a protein kinase A-mediated mechanism, which may be useful for developing potent melanogenesis stimulators.

Repigmentation of nipple-areola complex after ReCell® treatment on breast vitiligo

BACKGROUND

Nipple-areola complex is a naturally hyperpigmented skin area which can be involved in vitiligo. But limited study focused on the treatment of nipple-areola complex vitiligo, and few methods were proven to be effective. In this study, we aimed to explore the feasibility and efficacy of ReCell® on vitiligo in the nipple-areola complex area.

METHODS

Medical records of patients with vitiligo involving nipple-areola complex and underwent ReCell® treatment from October 2016 to April 2020 were retrospectively reviewed. The repigmentation rate of the nipple-areola complex and other breast area were calculated under the Wood's light at each follow-up. The grade of repigmentation and patient-reported satisfaction rate were also evaluated to prove the effect of ReCell® on vitiligo of breast and especially in the nipple-areola complex area.

RESULTS

A total of 18 patients were included in this study. No surgical complications were reported. The mean postoperative repigmentation rate in the nipple-areola complex area (3rd-month, 78.7 ± 5.8%; 6th-month, 87.6 ± 5.1%; and 12th-month, 96.1 ± 3.5%) was significantly higher than that in the other breast treatment area (3rd-month, 70.4 ± 6.9%; 6th-month, 84.2 ± 5.7%, and 12th-month, 93.2 ± 3.6%). All patients showed good or excellent grades at the last follow-up, and 94.4% of them considered the overall treatment results satisfactory.

CONCLUSIONS

ReCell® is a feasible and efficient treatment strategy in the nipple-areola complex vitiligo.

Vitiligo and chronic autoimmune thyroiditis

Vitiligo, the discoloration of the skin, has different autoimmune mechanisms reflected by many biomarkers as shown by skin histology, staining for CD4 and CD8 T lymphocytes, chemokine ligand 9 or circulating cytokines such as interleukin (IL)-1 beta, interferon (IFN)-gamma, transforming growth factor (TGF)-beta, antibodies, markers of oxidative stress, chemokines, and others. In this narrative review, we aim to overview vitiligo in relationship with chronic autoimmune thyroiditis. Regarding vitiligo, more than 50 different genetic loci have been associated with this disease, and the heritability is high. There is a 20% risk of an environmental connection which may also act as a trigger; moreover, the association with human leukocyte antigen (HLA) expression is well recognized. The specific lesions display CD8+ tissue-resident memory T cells as continuous key activators of melanocytes. The association with chronic thyroiditis is based on common autoimmune background and excessive reactive oxygen species that destroy melanocytes and thyrocytes (oxidative stress hypothesis) with thyroxine and melanin as target molecules, thus sharing a common origin: tyrosine. Moreover, common epigenetic anomalies or mutations of the Forkhead transcription factor D3 (FOXD3) have been described. Since vitiligo affects up to 1–2% of the population worldwide and 34% of patients have positive thyroid antibodies, apart from common autoimmunity background and oxidative stress toxicity, the association is clinically relevant for different practitioners.

Systemic CXCL10 is a predictive biomarker of vitiligo lesional skin infiltration, PUVA, NB-UVB and corticosteroid treatment response and outcome

Vitiligo is an acquired pigmentary skin disorder that currently lacks standardized treatment and validated biomarkers to objectively evaluate disease state or therapeutic response. Although prior studies have linked vitiligo autoimmunity with CXCL10/CXCL9-mediated recruitment of leukocytes to the skin, only limited clinical data are available regarding CXCL10 as vitiligo biomarker. To evaluate the utility of systemic CXCL10 as a predictor of disease progression and treatment response on a large cohort of vitiligo patients. CXCL10 levels in lesional, perilesional, and unaffected skin of vitiligo patient (n = 30) and in the serum (n = 51) were measured by quantitative ELISA. CXCL10 expression, recruitment of leukocytes, and inflammatory infiltrates were evaluated by histochemical (n = 32) and immunofluorescence (n = 10) staining. Rigorous cross-sectional and longitudinal biostatistical analysis were employed to correlate CXCL10 levels with disease variables, treatment response, and outcome. We demonstrated that elevated CXCL10 level (2 pg/mm² and higher) in lesional skin correlates with increased leukocytic infiltrate, disease duration (< 2 year), and its higher level in the serum (50 pg/ml and higher). Changes in CXCL10 serum levels in patients treated with psoralen plus UVA (PUVA) phototherapy, narrowband UVB (NB-UVB) phototherapy, and systemic steroids (SS) correlated with changes in the intralesional CXCL10 levels in repigmented skin. NB-UVB and SS regimens provided most consistent CXCL10 mean change, suggesting that these regimens are most effective in harnessing CXCR3-mediated inflammatory response. Serum CXCL10 is a useful vitiligo biomarker, which predicts lesional skin leukocytic infiltration, and vitiligo treatment response and outcome.

Retrospective analysis of off-label medication use at a plastic surgery hospital in China and evidence-based evaluation

To retrospectively analyze the off-label prescriptions at a plastic surgery hospital in China and conduct a literature review. The prescriptions in outpatient department from January 1, 2018 to December 31, 2018 were collected and compared with the related drug instructions in indications, dosage, frequency and route of administration to identify the off-label prescriptions. According to related literatures, guidelines, and MICROMEDEX, the rationality of off-label drug uses was evaluated. A total of 39 836 prescriptions were screened and 3395 (8.52%) off-label prescriptions were identified. It involved 23 items off-label medication uses. 20 items were off-label used in indication and three items were in indication and administration route. These off-label prescriptions involved 19 medicines and 12 indications and the dermatology related drug usage accounted for the largest proportion (91.3%). Additionally, five items (21.7%) were Chinese patent medicine related. Of the 23 items, seven (30.4%) have been recommended by guidelines and two (8.7%) by Thomson Grading System of Micromedex. All of them have been proved by literature evidence of level 1 to 4, in which 19 (82.6%) by Level 1 evidence, 21 (91.3%) by Level 1 to 2 evidence and 2 (8.7%) only by level 3 to 4 evidence. This can provide a theoretical basis to clinicians in prescribing. Our next work is to perfect some details about evidence assessment to improve the reliability.

Ultraviolet B irradiation enhances the secretion of exosomes by human primary melanocytes and changes their exosomal miRNA profile

Objective

Melanocytes play a central role in skin homeostasis. In this study, we focus on the function of melanocyte releasing exosomes as well as exosomal microRNAs (miRNAs) and investigate whether ultraviolet B (UVB) irradiation exerts an impact on it.

Materials and methods

Exosomes derived from human primary melanocytes were isolated through differential centrifugation and were identified in three ways, including transmission electron microscopy observation, nanoparticle tracking analysis, and Western blot analysis. Melanocytes were irradiated with UVB for the indicated time, and then melanin production and exosome secretion were measured. The exosomal miRNA expression profile of melanocytes were obtained by miRNA sequencing and confirmed by real-time PCR.

Results

Exosomes derived from human primary melanocytes were verified. UVB irradiation induced melanin production and increased the exosome release by the melanocytes. In total, 15 miRNAs showed higher levels in UVB-irradiated melanocyte-derived exosomes compared with non-irradiated ones, and the top three upregulated exosomal miRNAs were miR-4488, miR-320d, and miR-7704 (fold change > 4.0).

Conclusion

It is verified for the first time that UVB irradiation enhanced the secretion of exosomes by melanocytes and changed their exosomal miRNA profile. This findings open a new direction for investigating the communication between melanocytes and other skin cells, and the connection between UVB and skin malignant initiation.

Vitiligo: Mechanisms of Pathogenesis and Treatment

Vitiligo is an autoimmune disease of the skin that targets pigment-producing melanocytes and results in patches of depigmentation that are visible as white spots. Recent research studies have yielded a strong mechanistic understanding of this disease. Autoreactive cytotoxic CD8+ T cells engage melanocytes and promote disease progression through the local production of IFN-γ, and IFN-γ-induced chemokines are then secreted from surrounding keratinocytes to further recruit T cells to the skin through a positive-feedback loop. Both topical and systemic treatments that block IFN-γ signaling can effectively reverse vitiligo in humans; however, disease relapse is common after stopping treatments. Autoreactive resident memory T cells are responsible for relapse, and new treatment strategies focus on eliminating these cells to promote long-lasting benefit. Here, we discuss basic, translational, and clinical research studies that provide insight into the pathogenesis of vitiligo, and how this insight has been utilized to create new targeted treatment strategies.

Phototherapy in Skin of Color

Phototherapy in skin of color requires special consideration. Pigmented skin is an efficient ultraviolet filter. Hence, higher doses of ultraviolet radiation are generally more effective and well tolerated in skin of color. An objective and practical system has not yet been established to determine optimal phototherapy dosing in skin of color. The authors recommend obtaining a detailed history of each individual patient's response to sun exposure before prescribing a phototherapy dosing regimen. In addition, providers should consider the role of socioeconomic factors and their impact on phototherapy-related outcomes, including barriers to access and compliance.

A Network Pharmacology Approach to Uncover the Molecular Mechanisms of Herbal Formula Kang-Bai-Ling for Treatment of Vitiligo

Background

Kang-bai-ling (KBL), a Chinese patent medicine, has been demonstrated as an effective therapy for vitiligo in China. However, the pharmacological mechanisms of KBL have not been completely elucidated.

Methods

In this study, the potential multicomponent, multitarget, and multipathway mechanism of KBL against vitiligo was clarified by using network pharmacology-based strategy. In brief, potential targets of KBL were collected based on TCMSP databases, followed by network establishment concerning the interactions of potential targets of KBL with well-known therapeutic targets of vitiligo by using protein-protein interaction (PPI) data. As a result, key nodes with higher level of seven topological parameters, including “degree centrality (DC),” “betweenness centrality (BC),” “closeness centrality (CC),” “eigenvector centrality (EC),” “network centrality (NC),” and “local average connectivity (LAC)” were identified as the main targets in the network, followed by subsequent incorporation into the ClueGO for GO and KEGG signaling pathway enrichment analysis.

Results

In accordance with the topological importance, a total of 23 potential targets of KBL on vitiligo were identified as main hubs. Additionally, enrichment analysis suggested that targets of KBL on vitiligo were mainly clustered into multiple biological processes (associated with DNA translation, lymphocyte differentiation and activation, steroid biosynthesis, autoimmune and systemic inflammatory reaction, neuron apoptosis, and vitamin deficiency) and related pathways (TNF, JAK-STAT, ILs, TLRs, prolactin, and NF-κB), indicating the underlying mechanisms of KBL on vitiligo.

Conclusion

In this work, we successfully illuminated the “multicompounds, multitargets” therapeutic action of KBL on vitiligo by using network pharmacology. Moreover, our present outcomes might shed light on the further clinical application of KBL on vitiligo treatment.