Endothelial Cells Promote Pigmentation through Endothelin Receptor B Activation

Tranexamic Acid for the Treatment of Hyperpigmentation and Telangiectatic Disorders Other Than Melasma: An Update

Tranexamic acid (TXA), a synthetic lysine analog, is a commonly used antifibrinolytic and procoagulant agent. Based on its good hemostatic efficacy, it is mainly used clinically for bleeding in trauma, various types of surgical and dental procedures and prevention of bleeding in patients with hemophilia. In recent years, studies have shown that TXA has the effects of anti-melanogenesis, anti-inflammation, anti-angiogenesis and promotes the recovery of the skin barrier, so it has been tried to be used as a treatment for hyperpigmentation and telangiectatic diseases. Oral, topical, intradermal injections and microneedling are all commonly used modes of administration. TXA for melasma is the most studied and has achieved indications in some countries, whereas it is still an off-label drug for many other dyschromia. We review the clinical use of TXA in hyperpigmentation and telangiectatic disorders other than melasma, such as post-inflammatory hyperpigmentation, Riehl's melanosis, rosacea, and post-acne erythema, to provide more evidence for the use of TXA in these disorders, and to provide safer and more cost-effective alternatives for the treatment of these diseases.

A systems view of the vascular endothelium in health and disease

The dysfunction of blood-vessel-lining endothelial cells is a major cause of mortality. Although endothelial cells, being present in all organs as a single-cell layer, are often conceived as a rather inert cell population, the vascular endothelium as a whole should be considered a highly dynamic and interactive systemically disseminated organ. We present here a holistic view of the field of vascular research and review the diverse functions of blood-vessel-lining endothelial cells during the life cycle of the vasculature, namely responsive and relaying functions of the vascular endothelium and the responsive roles as instructive gatekeepers of organ function. Emerging translational perspectives in regenerative medicine, preventive medicine, and aging research are developed. Collectively, this review is aimed at promoting disciplinary coherence in the field of angioscience for a broader appreciation of the importance of the vasculature for organ function, systemic health, and healthy aging.

Semaxanib, a VEGF inhibitor, suppresses melanogenesis by modulating CRTC3 independently of VEGF signaling

BACKGROUND

Dysregulation of melanogenesis contributes to the development of skin hyperpigmentation diseases, which poses a treatment challenge. Following the establishment of CRTC3 screening methods to explore small molecules inhibiting melanogenesis for the topical treatment of hyperpigmentation diseases, we identified a candidate molecule, semaxanib.

OBJECTIVE

To explore the antimelanogenic effects of semaxanib, a vascular endothelial growth factor receptor (VEGFR) 2 inhibitor, for potential applications in hyperpigmentation management and to unravel the role of VEGF signaling in melanocyte biology by investigating mechanism of action of semaxanib.

METHODS

Mouse-derived spontaneously immortalized melanocytes, B16F10, and normal human primary epidermal melanocytes cells were treated with semaxanib, and cellular responses were assessed using cell viability assays and melanin content measurements. Molecular mechanisms were investigated using transcriptional activity assays, reverse-transcription polymerase chain reaction, and immunoblotting analysis. In vivo studies were conducted using an epidermis-humanized transgenic mouse model and ex vivo human skin tissues.

RESULTS

Semaxanib ameliorated melanin content in cultured melanocytes by downregulating the expression of melanogenesis-associated genes by suppressing the CRTC3/microphthalmia-associated transcription factors. Topical application of semaxanib reduced melanin accumulation in the ultraviolet B-stimulated ex vivo human epidermis and tail of K14-stem cell factor transgenic mice. Mechanistically, the antimelanogenic effect induced by semaxanib was associated with SIK2-CRTC3-MITF rather than VEGF signaling in melanocytes.

CONCLUSION

Semaxanib emerges as a promising candidate for the development of therapeutics for hyperpigmentation, potentially working independently of VEGF signaling in human melanocytes.

What lies behind melasma: a review of the related skin microenvironment

Melasma is an acquired chronic pigmentary disorder affecting millions of individuals worldwide. However, the pathogenesis of melasma remains unclear. This article provides a comprehensive review of the pathophysiological changes occurring in the skin microenvironment of melasma lesions, which can be summarized as follows: (1) skin barrier dysfunction and abnormal synthesis, transport, and intracellular distribution of melanin in the epidermis; (2) basement membrane damage; (3) solar elastosis, vascular changes, senescent fibroblasts, mast cell infiltration, and sebocyte participation in the dermis; and (4) systemic factors such as sex hormones and oxidative stress. Furthermore, potential therapeutic strategies are introduced to provide novel perspectives for fundamental and clinical research related to melasma.

G Protein-Coupled Receptors in Skin Aging

Skin aging is a complex biological process affected by a plethora of intrinsic and extrinsic factors that alter cutaneous functions through the modulations of signaling pathways and responses. Expressed in various cell types and skin tissue layers, G protein-coupled receptors (GPCRs) play a vital role in regulating skin aging. We have cataloged 156 GPCRs expressed in the skin and reviewed their roles in skin aging, such as pigmentation, loss of elasticity, wrinkles, rough texture, and aging-associated skin disorders. By exploring the GPCRs found in the skin, it may be possible to develop new treatment regimens for aging-associated skin conditions using GPCR ligands.

Efficacy of Vitamin B12 and Adenosine Triphosphate in Enhancing Skin Radiance: Unveiled with a Drug-Target Interaction Deep Learning-Based Model

Skin radiance is crucial for enhancing facial attractiveness and is negatively affected by factors like hyperpigmentation and aging-related changes. Current treatments often lack comprehensive solutions for improving skin radiance. This study aimed to develop a cosmetic formula that enhances skin radiance by reducing hyperpigmentation and improving skin regeneration by targeting specific receptors-the endothelin receptor type B (EDNRB) for hyperpigmentation and the adiponectin receptor 1 (ADIPOR1) for sagging and wrinkles. To achieve this, we used artificial intelligence technologies to screen and select ingredients with an affinity for EDNRB and ADIPOR1. Vitamin B12 (VitB12) was identified as a molecule that targets EDNRB, which is involved in melanogenesis. Adenosine triphosphate (ATP) targets ADIPOR1, which is associated with skin regeneration. VitB12 successfully inhibited intracellular calcium elevation and melanogenesis induced by endothelin-1. In contrast, ATP increased the mRNA expression of collagen and elastin and promoted wound healing. Moreover, the VitB12 and ATP complex significantly increased the expression of hyaluronan synthases, which are crucial for skin hydration. Furthermore, in human participants, the application of the VitB12 and ATP complex to one-half of the face significantly improved skin radiance, elasticity, and texture. Our findings provide valuable insights for the development of skincare formulations.

Global research trends on melasma: a bibliometric and visualized study from 2014 to 2023

Melasma, a prevalent pigmentary disorder, is characterized by its complex etiology, propensity for recurrence, and resistance to treatment. However, there is currently no research on melasma through bibliometrics and visualisation. This study analyses the hotspots and trends in the field based on 2,709 publications from the Web of Science Core Collection (WOSCC). We carried out bibliometric analyses using Citespace software for different countries/regions, institutions, authors, and keywords. References were also analysed using VoSviewer. The results indicate that overall, there has been an increase in publications related to melasma since 2014. According to the analysis of the collaborative network diagram, the United States, Egyptian Knowledge Bank, and Benjakul Soottawat are the most contributing countries, institutions, and authors, respectively. Reference and keyword analyses have identified the pathogenesis and treatment of melasma as a prevalent topic in recent years. And how to find new treatment options and more effective therapeutic drugs is a future research trend. This is the first bibliometric and visual analysis of melasma-related literature to explore research hotspots and trends.

Investigating the impact of pigmentation variation of breast muscle on growth traits, melanin deposition, and gene expression in Xuefeng black-bone chickens

The blackness traits, considered an important economic factor in the black-bone chicken industry, still exhibits a common phenomenon of significant difference in blackness of breast muscle. To improve this phenomenon, this study compared growth traits, blackness traits, and transcriptome of breast muscles between the High Blackness Group (H group) and Low Blackness Group (L group) in the Xuefeng black-bone chickens. The results are as follows: 1) There was no significant difference in growth traits between the H group and the L group (P > 0.05). 2) The skin/breast muscle L values in the H group were significantly lower than those in the L group, while the breast muscle melanin content exhibited the opposite trend (P < 0.05). 3) A significant negative correlation was observed between breast muscle melanin content and skin/breast muscle L value (P < 0.05), and skin L value exhibiting a significant positive correlation with breast muscle L value (P < 0.05). 4) The breast muscle transcriptome comparison between the H group and L group revealed 831 and 405 DEGs in female and male chickens, respectively. This included 37 shared DEGs significantly enriched in melanosome, pigment granule, and the melanogenesis pathway. Seven candidate genes (DCT, PMEL, MLANA, TYRP1, OCA2, EDNRB2, and CALML4) may play a crucial role in the melanin production of breast muscle in Xuefeng black-bone chicken. The findings could accelerate the breeding process for achieving desired levels of breast muscle blackness and contribute to the exploration of the mechanisms underlying melanin production in black-bone chickens.

Update on Melasma Treatments

Melasma is a prevalent hyperpigmentation condition known for its challenging treatment due to its resemblance to photoaged skin disorders. Numerous studies have shed light on the intricate nature of melasma, which often bears similarity to photoaging disorders. Various therapeutic approaches, encompassing topical and systemic treatments, chemical peeling, and laser therapy, have exhibited efficacy in managing melasma in previous research. However, melasma often reoccurs despite successful treatment, primarily due to its inherent photoaged properties. Given that melasma shares features with photoaging disorders, including disruptions in the basement membrane, solar elastosis, angiogenesis, and mast cell infiltration in the dermal layer, a comprehensive treatment strategy is imperative. Such an approach might involve addressing epidermal hyperpigmentation while concurrently restoring dermal components. In this article, we provide a comprehensive review of conventional treatment methods frequently employed in clinical practice, as well as innovative treatments currently under development for melasma management. Additionally, we offer an extensive overview of the pathogenesis of melasma.

Tranexamic Acid Ameliorates Skin Hyperpigmentation by Downregulating Endothelin-1 Expression in Dermal Microvascular Endothelial Cells

BACKGROUND

Although reports suggest that tranexamic acid (TXA) has clinical benefits for melasma patients by oral, intralesional and topical treatment, the optimal route of TXA therapy and the underlying mechanism involved remain poorly defined.

OBJECTIVE

To compare the skin lightening effect between oral TXA and topical TXA and to dissect the molecular mechanisms using ultraviolet B (UVB)-induced hyperpigmentation mouse model, ex vivo cultured human skin explant, and cultured melanocytes (MCs) and endothelial cells.

METHODS

Melanin content and cluster of differentiation 31 (CD31)-positive cell numbers were measured in tail skins from UVB-irradiated mice treated by intragastral or topical TXA using immunofluorescent and Fontana-Masson staining. The conditioned medium (CM) was harvested from human umbilical vein endothelial cells treated with or without 3 mM TXA and was used to treat MCs for 48 hours. mRNA and protein levels of tyrosinase and microphthalmia-associated transcription factor were measured using quantitative real-time reverse transcription polymerase chain reaction and western blotting assays. HMB45- and CD31-positive cell numbers as well as melanin content were also examined in ex vivo cultured human skin explants.

RESULTS

The hyperpigmented phenotype were significantly mitigated in UVB-irradiated tail skin plus intragastral TXA-treated mice compared with mice treated with UVB only or with UVB plus topical TXA. CD31-positive cell numbers correlated with the anti-melanogenic activity of TXA therapy. The data from cultured cells and skin tissues showed that suppression of endothelin-1 (ET-1) in vascular endothelial cells by TXA reduced melanogenesis and MC proliferation.

CONCLUSION

Oral TXA outperforms topical TXA treatment in skin lightening, which contributes to suppression of ET-1 in dermal microvascular endothelial cells by TXA.

The Yucatan miniature swine as a model for post-inflammatory hyperpigmentation

Post-inflammatory hyperpigmentation (PIH) is a hypermelanosis that often occurs secondary to skin irritation or injury, especially in darker skin tones, for which there is currently a lack of effective treatment options. Few preclinical models are available to study PIH. Here, we show that the Yucatan miniature pig consistently develops PIH after skin injuries. Skin wounds were produced on Yucatan pigs by needle punches, full-thickness excisions, or burns. Wound sites were monitored and photographed regularly. Tissue samples were collected after 24 weeks and processed for histology/immunohistochemistry. Skin pigmentation and histologic changes were quantified by computer-assisted image analyses. All injury methods resulted in hyperpigmentation. Melanin content at the histologic level was quantified in the larger (burn and excision) wounds, showing a significant increase compared to uninjured skin. Increased melanin was found for both epidermal and dermal regions. Dermal melanin deposits were primarily clustered around the papillary vasculature, and were associated not with melanocytes but with leukocytes. The Yucatan miniature pig model recapitulates key clinical and histologic features of PIH in humans, including skin hyperpigmentation at both gross and histologic levels, and persistence of dermal melanin subsequent to injury. This model could be used to further our understanding of the etiology of PIH, and for new therapy development.

Characteristics of dermal vascularity in melasma and solar lentigo

BACKGROUND /PURPOSE

Melasma and solar lentigo (SL) are major benign hyperpigmented lesions, and both have been shown to involve the dermal vasculature. This review discusses current knowledge regarding the clinical characteristics of dermal vascularity in melasma and SL, as well as the results of relevant molecular biological investigations.

METHODS

PubMed and Google Scholar were searched in December 2023 to identify articles related to melasma, SL, and the dermal vasculature in these lesions.

RESULTS

Vascular morphologies in melasma and SL have been detected by histological and non-invasive methods, including modalities such as optical coherence tomography. Biological studies have indicated that factors secreted from vascular endothelial cells, such as stem cell factor and endothelin-1, can promote melanogenesis. With respect to phototherapy, blood vessel-targeting laser treatments are expected to provide long-term suppression of pigmentation, but this regimen is only effective when dilated capillaries are visible.

CONCLUSION

In both melasma and SL, clinical and experimental investigations are revealing the contributions of dermal vascularity to hyperpigmentation. More effective treatment may require identification of hyperpigmentation subtypes. In the future, knowledge of treatment (including phototherapy) is expected to accumulate through reliable and validated non-invasive measurements.

Targeting the dermis for melasma maintenance treatment

Melasma relapse is almost common after discontinuation of conventional treatment. Recent studies suggesting that photoaging dermis is the main pathomechanism of melasma, emphasize the dermal targeting therapy. We investigated maintenance effect of microneedling radiofrequency (RF) for melasma treatment. Subjects with melasma were administered oral tranexamic acid and triple combination cream for 2 months and a randomly assigned half face was treated with RF. After discontinuation of conventional therapy, the half face RF continued monthly over 6 months. Modified melasma area severity index (mMASI) score and L* value by a chromameter were collected monthly. Fifteen subjects were enrolled and eleven completed the 8-month study. At 2nd month of conventional therapy, all subjects showed improvement with a 64% reduction in mMASI score. With continuous RF treatment, the improvement was well maintained; whereas in untreated side, the Δ L* gradually decreased, returning to the baseline after the conventional therapy ended. The continuous microneedling RF therapy is beneficial in maintaining the conventional therapy of melasma suggesting the protective effect of dermal targeting therapy in melasma development.(Clinical Trial registration number: NCT05710068, date of first registration: 02/02/2023).

The Mechanism of 5-Fluorouracil-Induced Hyperpigmentation in HRM-2 Hairless Mice: Focus on the Increase of Blood Vessels

5-Fluorouracil (5-FU), an effective chemotherapeutic agent for many solid tumors, has long been reported to cause pigmentation in patients treated intravenously, which occurs with increasing frequency of administration and decreases the QOL of the patients. Although melanin accumulation is thought to be the cause, the mechanism of pigmentation induced by 5-FU administration remains unclear, and there is no effective treatment for this problem. In this study, we investigated the mechanism of pigmentation induced by continuous 5-FU administration in 9-week-old male HRM-2 hairless mice for 8 weeks by focusing on the blood vessels for basic verification. In the auricular skin of 5-FU-administered mice, hyperpigmentation caused by melanin accumulation was observed macroscopically and by Fontana-Masson Staining. In addition, the expression of tyrosinase, melanin synthase, and blood vessel markers in the auricular skin was increased by 5-FU-administration in mice auricular skin. Other anticancer agents, cytarabine (Ara-C) and irinotecan (CPT-11), were also administered, and the differences between them and 5-FU were investigated; these changes were not observed in the auricles of these mice. These results suggest that tyrosinase is associated with 5-FU-induced melanin production and that an increase in blood vessels may be involved. Furthermore, pigmentation with melanin accumulation in the basal epidermal layer is a characteristic finding of 5-FU compared with Ara-C and CPT-11. In conclusion, this study indicates that 5-FU causes hyperpigmentation by melanin accumulation in a characteristic manner, including an increase in blood vessels.

Expression of Endothelin-1, Endothelin Receptor-A, and Endothelin Receptor-B in facial melasma compared to adjacent skin

Background/Objectives

Although melasma is highly prevalent, its pathogenesis is not yet fully understood. In the skin, endothelin-1 (ET-1) is primarily produced by keratinocytes in response to UVB exposure, which is mediated by an increase in IL-1α or reactive oxygen species. ET-1 plays a role in melanogenesis by binding to specific receptor B (ERB) or receptor A (ERA). However, the expression of ET-1, ERA, and ERB in melasma has not been systematically investigated. The objective of this study was to evaluate the expression of ET-1, ERA, and ERB in facial melasma compared to the adjacent unaffected skin.

Methods

Cross-sectional study, with 40 skin samples (20: facial melasma; 20: adjacent unaffected skin) from women with facial melasma without treatment for 30 days except for sunscreen. A triple staining immunofluorescence technique was performed for anti-vimentin, DAPI, plus one of the following antibodies: (a) anti-ET1, (b) anti-ERA; (c) anti-ERB. Interfollicular areas on the slides of each topography (melasma; unaffected skin) were photographed in triplicate under confocal laser microscopy. The mean staining intensities of the image histograms (0-255 pixels intensity) were estimated for different types of cells (suprabasal keratinocytes, basal layer, and upper dermis) and were blindly compared between topographies.

Results

The mean (SD) age of the participants was 44.9 (9.2). The expression of ET-1 was increased in the whole epidermis with melasma when compared to the adjacent skin, being 32.8% (CI95% 14.7%-52.6%) higher in the spinous layer (p=0.013), 30.4% (CI95% 13.7%-47.9%) higher in the basal layer (p=0.014), and 29.7% (CI95% 11.4%-49.7%) higher in the melanocytes (p=0.006). There was no noticeable expression of ET-1 within the cells on the upper dermis. Neither ERA nor ERB resulted in differential epidermal expression between melasma and unaffected skin (p≥0.1).

Conclusion

ET-1 is expressed more intensely on the epidermis from the skin with facial melasma compared to the unaffected adjacent skin.

The effect of Salix alba L. bark extract on dark circles in vitro and in vivo

OBJECTIVE

Dark circles in the infraorbital area are a common cosmetic concern among individuals because they exhibit fatigue and are undesirable across all ages. Of the dark circle etiologies, blood stasis by poor-vascular integrity can cause darkening of the lower eyelid skin, which might be alleviated by reduced endothelial permeability. In this study, we investigated the effects of Salix alba bark extract (SABE) on the synthesis of hyaluronic acid (HA) in fibroblasts and vascular integrity protection from inflammatory cytokine. We also performed a clinical trial investigating the effect of SABE on dark circles.

METHODS

To confirm the effect of SABE on HA synthesis in human dermal fibroblasts (HDFs), we performed ELISA and real-time PCR. We investigated the interaction HDF-secreted substance with vascular integrity, and human dermal microvascular endothelial cells (HMEC-1) were treated with conditioned medium (CM) from HDF treated with or without SABE. Subsequently, we conducted a clinical study on 29 subjects by having them apply SABE containing cream for 8 weeks.

RESULTS

Salix alba bark extract treatment increased HA synthesis and regulated HMW-HA-related gene expressions in HDF. CM from SABE-treated HDF alleviated endothelial permeability and led to improved vascular integrity in HMEC-1 cells. Treatment with the cream containing 2% SABE for 8 weeks improved the parameters measuring dark circles, skin microcirculation and elasticity.

CONCLUSION

Our results showed that SABE could protect against dark circles in vitro, and that topical treatment of SABE improved the clinical indexes of dark circles in a clinical study. Therefore, SABE can be used as an active ingredient for improving dark circles.

Hydrolyzed Conchiolin Protein (HCP) Extracted from Pearls Antagonizes both ET-1 and α-MSH for Skin Whitening

Pearl powder is a famous traditional Chinese medicine that has a long history in treating palpitations, insomnia, convulsions, epilepsy, ulcers, and skin lightining. Recently, several studies have demonstrated the effects of pearl extracts on protection of ultraviolet A (UVA) induced irritation on human skin fibroblasts and inhibition of melanin genesis on B16F10 mouse melanoma cells. To further explore the effect we focused on the whitening efficacy of pearl hydrolyzed conchiolin protein (HCP) on human melanoma MNT-1 cells under the irritation of alpha-melanocyte-stimulating hormone (α-MSH) or endothelin 1 (ET-1) to evaluate the intracellular tyrosinase and melanin contents, as well as the expression levels of tyrosinase (TYR), tyrosinase related protein 1 (TRP-1), and dopachrome tautomerase (DCT) genes and related proteins. We found that HCP could decrease the intracellular melanin content by reducing the activity of intracellular tyrosinase and inhibiting the expression of TYR, TRP-1, DCT genes and proteins. At the same time, the effect of HCP on melanosome transfer effect was also investigated in the co-culture system of immortalized human keratinocyte HaCaT cells with MNT-1. The result indicated that HCP could promote the transfer of melanosomes in MNT-1 melanocytes to HaCaT cells, which might accelerate the skin whitening process by quickly transferring and metabolizing melanosomes during keratinocyte differentiation. Further study is needed to explore the mechanism of melanosome transfer with depigmentation.

New Mechanistic Insights of Melasma

Melasma is a common acquired disorder of pigmentation that negatively impacts quality of life. Present treatments show poor therapeutic effect with frequent recurrence. This in large part is due to the currently limited understanding of the disease's etiology. It is urgent to elucidate the pathogenesis of melasma to further the discovery of new therapeutic strategies. Recent studies show that melasma is triggered or aggravated by a variety of factors, including genetic susceptibility, ultraviolet radiation, and sex hormone dysregulation. Ultraviolet B radiation upregulates the expression of several melanocyte-specific genes and stimulates the release of key factors that participate in the synthesis of melanin. There is a significant increase in melanin in both the epidermal and dermal layers of affected skin, possibly due to abnormalities in crosstalk between the melanocytes and other cells. Melanogenesis is regulated through various signaling networks including the Wnt/β-catenin, PI3K/Akt, cAMP/PKA, and SCF/c-kit-mediated signaling pathways. In addition, inflammatory mediators, oxidative stress, neuroactive molecules, sebocytes, etc, have also been proved to be related to the pathogenesis of melasma. This review provides a comprehensive update on the current understanding of the pathogenesis of melasma.

Depigmenting topical therapy based on a synergistic combination of compounds targeting the key pathways involved in melasma pathophysiology

Melasma has a complex pathophysiology with different cell types and signalling pathways involved. Paracrine factors secreted by keratinocytes, fibroblasts and endothelial cells act on melanocytes and stimulate melanogenesis. These paracrine factors are involved in the oxidative stress, inflammatory, vascular and hormonal pathways, among others. Damage of the dermoepidermal barrier also occurs and facilitates melanin deposition in the dermis, also known as dermal or mixed melasma. We used artificial intelligence tools to define the best combination of compounds for skin pigmentation inhibition. Mathematical models suggested the combination of retinol, diosmin and ferulic acid to be the most effective one. In vitro cellular tyrosinase activity assay proved that this combination had a synergistic depigmenting effect. Further assays proved that the combination could inhibit key pathways involved in melasma by downregulating ET-1 and COX-2 gene expression and IBMX-induced dendricity in human melanocytes, and upregulated the gene expression of IL-1b, TIMP3 and several endogenous antioxidant enzymes. The combination also reduced melanin levels in a phototype VI 3D epidermis model. These results indicate that the combination of retinol, diosmin and ferulic acid is an effective synergistic complex for the treatment of melasma by regulating the key molecular pathways involved in skin hyperpigmentation pathophysiology.

Angiotropic melanocytes: Possibly a distinctive finding in extra-facial acquired dermal melanocytosis

BACKGROUND

Acquired dermal melanocytosis is a heterogenous group of hyperpigmented lesioins which predominantly involve the face.

AIM

The aim of this study was to study the clinical presentation and histopathology of cases with extra-facial acquired dermal melanocytosis.

METHODS

Retrospective record analysis was performed between May 2016 to August 2019 to retrieve cases of extra-facial acquired dermal melanocytosis seen at the out-patient department of dermatology at the All India Institute of Medical Sciences, Jodhpur. Consecutive cases with histopathologically proven diagnosis of acquired dermal melanocytosis were included. Documentation of variation in clinical presentation and histopathologic findings was done in light of the existing literature.

RESULTS

Overall, four cases of extra-facial acquired dermal melanocyosis (female:male = 1:3) were seen during the study period. The lone case on head and neck involved the ear lobule and peri-auricular area. The other three cases had involvement of the hand. The histopathology confirmed the diagnosis of dermal melanocytosis but revealed peculiar findings of angiotropic melanocytes and dilated capillaries.

LIMITATIONS

Small sample size and lack of comparison with perilesional normal skin were the limitations of this study.

CONCLUSION

The findings of angiotropic melanocytes may be unique to extra-facial acquired dermal melanocytosis. This might indicate interaction between dermal melanocytes and capillary endothelial cells. This finding along with dermal capillary ectasia may indicate a possible role for vascular lasers in the management of these disorders.

590 nm LED Irradiation Improved Erythema through Inhibiting Angiogenesis of Human Microvascular Endothelial Cells and Ameliorated Pigmentation in Melasma

Melasma is a common refractory acquired pigmentary skin disease that mainly affects middle-aged women. The pathogenesis of melasma is still uncertain, while abnormal vascular endothelial cells may play a role. We previously demonstrated the yellow light of light-emitting diodes (LED) could inhibit melanogenesis through the photobiomodulation (PBM) of melanocytes and keratinocytes. In the current study, we investigated the effect of 590 nm LED on the function of human microvascular endothelial cells (HMEC-1). We revealed 0-40 J/cm² 590 nm LED had no toxic effect on HMEC-1 in vitro. 590 nm LED irradiation significantly reduced cell migration, tube formation, as well as the expression of vascular endothelial growth factor (VEGF) and stem cell factor (SCF), a pro-melanogenic factor. Moreover, we illustrated that 590 nm LED inhibited the phosphorylation of the AKT/PI3K/mTOR signaling pathway, and the inhibitory effect on HMEC-1 could be partially reversed by insulin-like growth factor 1 (IGF-1), an AKT/PI3K/mTOR pathway agonist. Besides, we conducted a pilot clinical study and observed a marked improvement on facial erythema and pigmentation in melasma patients after amber LED phototherapy. Taken together, 590 nm LED inhibited HMEC-1 migration, tube formation and the secretion of VEGF and SCF, predominantly through the inhibition of the AKT/PI3K/mTOR pathway, which may serve as a novel therapeutic option for melasma.

Mechanism of Action of Topical Tranexamic Acid in the Treatment of Melasma and Sun-Induced Skin Hyperpigmentation

Tranexamic acid (TXA) has anti-plasmin activity and has been shown when administered orally to be effective against melasma, for which it is considered first-line pharmacotherapy. Several studies have shown that topically applied TXA is also effective against melasma and skin hyperpigmentation caused by sunburn and inflammation. The TXA concentration in the epidermis and dermis/vasculature has been estimated from its distribution in the skin after closed application, and topically applied TXA has thus been shown to act on neutrophils and mast cells in the dermis and on the vascular system. It is unlikely that topically applied TXA acts on dermal neutrophils or mast cells or on the vascular system to form thrombi. As discussed in the present review, studies on the effects of topical TXA on the hyperpigmentation process indicate that the resulting skin-lightening mechanism involves the suppression of cytokine/chemical mediator production, which stimulates melanin production via the keratinocyte-derived urokinase-type plasminogen activator and plasminogen derived from dermal vascular in the basal layer of the epidermis, thereby suppressing the production of excessive melanin to prevent hyperpigmentation.

Understanding Melasma-How Can Pharmacology and Cosmetology Procedures and Prevention Help to Achieve Optimal Treatment Results? A Narrative Review

Melasma is a chronic skin condition that involves the overproduction of melanin in areas exposed to ultraviolet radiation. Melasma treatment is long-term and complicated with recurrence and resistance to treatment. The pathogenesis of melasma is highly complex with multiple pathologies occurring outside of the skin pigment cells. It includes photoaging, excessive melanogenesis, an increased number of mast cells, increased vascularization, and basement membrane damage. In addition, skin lesions related to melasma and their surrounding skin have nearly 300 genes differentially expressed from healthy skin. Traditionally, melasma was treated with topical agents, including hydroquinone, tretinoin, glucocorticosteroids and various formulations; however, the current approach includes the topical application of a variety of substances, chemical peels, laser and light treatments, mesotherapy, microneedling and/or the use of systemic therapy. The treatment plan for patients with melasma begins with the elimination of risk factors, strict protection against ultraviolet radiation, and the topical use of lightening agents. Hyperpigmentation treatment alone can be ineffective unless combined with regenerative methods and photoprotection. In this review, we show that in-depth knowledge associated with proper communication and the establishment of a relationship with the patient help to achieve good adherence and compliance in this long-term, time-consuming and difficult procedure.

Human sensory neurons modulate melanocytes through secretion of RGMB

Melanocytes are surrounded by diverse cells, including sensory neurons in our skin, but their interaction and functional importance have been poorly investigated. In this study, we find that melanocytes and nociceptive neurons contact more in human skin color patch tissue than control. Co-culture with human iPSC-derived sensory neurons significantly induces morphogenesis and pigmentation of human melanocytes. To reveal melanocyte-stimulating factors secreted from neurons, we perform proteomic analyses and identify RGMB in the sensory neuron-conditioned medium. RGMB protein induces morphogenesis and melanin production of melanocytes, demonstrating that RGMB is a melanocyte-stimulating factor released from sensory neurons. Transcriptome analysis suggests that the melanosome transport machinery can be controlled by RGMB, leading us to identify the vesicle production response of melanocytes upon RGMB treatment. This study discovers a role of sensory neurons in modulating multiple aspects of human melanocytes through secretion of a key factor: RGMB.

Skin-Aging Pigmentation: Who Is the Real Enemy?

Skin aging is induced and sustained by chronological aging and photoaging. Aging skin pigmentation such as mottled pigmentation (senile lentigo) and melasma are typical signs of photoaging. The skin, like other human organs, undergoes cellular senescence, and senescent cells in the skin increase with age. The crosstalk between melanocytes as pigmentary cells and other adjacent types of aged skin cells such as senescent fibroblasts play a role in skin-aging pigmentation. In this review, we provide an overview of cellular senescence during the skin-aging process. The discussion also includes cellular senescence related to skin-aging pigmentation and the therapeutic potential of regulating the senescence process.

Treatment of melasma by a combination of intense pulsed light with advanced optimal pulse technology and human-like collagen repair dressing: A case series study

To observe the efficacy and safety of a combination of intense pulsed light (IPL) with advanced optimal pulse technology (AOPT) and human-like collagen repair dressing in the treatment of melasma. Ten patients with melasma were treated using IPL with AOPT once a month for a total of 8 times, and received the treatment of external human-like collagen repair dressing after each operation. The efficacy was evaluated with the modified Melasma Area Severity Index (mMASI) score and satisfaction score, respectively, before treatment, after each treatment and at 4 months after the end of the whole treatment course. The melasma was significantly lightened in all 10 patients after 8 times of treatments. The mMASI score before treatment was (8.6 ± 3.8) points, which decreased significantly to (5.1 ± 2.7) points after 8 times of treatments, and there was a significant difference in mMASI score between before and after 8 times of treatments (P = .001). The mMASI score was (3.3 ± 2.2) points at 4 months after the end of whole treatment course, and there was no significant difference in mMASI score between after 8 times of treatments and 4 months after the end of whole treatment course (P > .05). The satisfaction score was (7.2 ± 1.4) points after 8 times of treatments and (7.1 ± 1.4) points at 4 months after the end of whole treatment course, there was no significant difference in satisfaction score between after 8 times of treatments and 4 months after the end of whole treatment course (P > .05). A combination of IPL with AOPT and human-like collagen repair dressing can effectively decrease the severity of melasma, and is associated with a higher patient satisfaction score and a lower risk of relapse after discontinuation of treatment.

Update on Melasma-Part I: Pathogenesis

Melasma is a multifactorial dyschromia that results from exposure to external factors (such as solar radiation) and hormonal factors (such as sex hormones and pregnancy), as well as skin inflammation (such as contact dermatitis and esthetic procedures), in genetically predisposed individuals. Beyond hyperfunctional melanocytes, skin with melasma exhibits a series of structural and functional alterations in the epidermis, basement membrane, and upper dermis that interact to elicit and sustain a focal hypermelanogenic phenotype. Evolution in the knowledge of the genetic basis of melasma and the cutaneous response to solar radiation, as well as the roles of endocrine factors, antioxidant system, endothelium proliferation, fibroblast senescence, mast cell degranulation, autophagy deficits of the melanocyte, and the paracrine regulation of melanogenesis, will lead to the development of new treatments and preventive strategies. This review presents current knowledge on these aspects of the pathogenesis of melasma and discusses the effects of specific treatments and future research on these issues.

Efficacy and Safety of Using Noninsulated Microneedle Radiofrequency Alone Versus in Combination with Polynucleotides for the Treatment of Melasma: A Pilot Study

Introduction

This split-face, double-blind, randomized controlled study investigated the efficacy and safety of using a microneedling radiofrequency (RF) device with polynucleotides (PN) versus RF alone for the treatment of melasma.

Methods

Thirty adult participants with melasma (Fitzpatrick skin types III–V) received three treatments with an invasive, bipolar, pulsed-type microneedling RF device on both sides of the face. The treatment sessions occurred once every 2 weeks. The hemifaces of each participant were designated for treatment and control with PN and normal saline solution (NSS), applied after treatment with RF. Measurements were made of melanin index (MI), erythema index (EI), skin roughness (by the Antera 3D system), modified melasma area severity index (mMASI) for each hemiface, and patients’ self-assessed improvement. These occurred at baseline and again following the final treatment (2 weeks and 1, 2, 3, and 6 months after). Mean values were obtained for MI, EI, skin roughness, and mMASI. A generalized estimating equation (GEE) was used to compare the obtained values for the outcome measures across all assessment points.

Results

All patients were women (mean age, 43.2 ± 7.0 years). Mixed melasma predominated (61.5%; n = 16), and the mean duration of melasma was 8.9 ± 6.5 years. Twenty-six participants were followed up to the 6-month assessment point. Significant improvements were observed from baseline in MI, skin roughness, and mMASI scores for both the PN and control sides at 6 months, with no statistically significant differences between sides. Patients’ self-assessed improvement scores also showed a positive trend. Melasma recurrence was observed in three patients at 2, 3, and 4 months after the last treatment session (10% recurrence rate).

Conclusions

The combination of an invasive, bipolar, pulsed-type microneedling RF with PN is not superior compared with microneedling RF alone in the treatment of melasma. Microneedling RF may be considered as safe and efficacious for the improvement of skin roughness, and as an adjunctive treatment option for melasma.

Clinical Trial Registration

This study was registered on ClinicalTrials.gov and assigned NCT number TCTR20210804002.

A comparative evaluation of the efficacy of intralesional tranexamic acid versus platelet rich plasma in the treatment of melasma

Melasma is a benign, acquired disorder of hyperpigmentation commonly affecting the face. Though easily diagnosable, a tangible treatment for melasma still remains elusive. Our aim was to compare the therapeutic efficacy and safety of tranexamic acid (TXA) and platelet rich plasma (PRP) microinjections in treating patients with melasma. In total, 40 patients with melasma (10 males, 30 females; age range: 21-54 years) were enrolled, and randomly assigned to one of the two groups consisting of 20 patients each. Group A (3 males, 17 females) received intradermal microinjections of TXA (4 mg/ml) and group B (5 males, 15 females) received intradermal microinjections of PRP, once every 4 weeks for a total of five treatment sessions. Clinical images were taken at each visit and improvement in melasma was evaluated using both melasma area severity index (MASI) and modified melasma area severity index (mMASI) scoring systems. Percentage reduction of both MASI and mMASI scores were also assessed at each visit, and the grade of melasma improvement was accordingly outlined for each patient. The study was completed by 18 patients in group A (TXA) and 15 patients in group B (PRP). In group A, both MASI and mMASI scores reduced significantly from 16.6 ± 9.227 at baseline to 10.028 ± 8.07 at end point; and 8.885 ± 5.418 at baseline to 4.639 ± 3.863 at end point, respectively (p value <0.01). Similarly in group B significant reduction in both scores were observed at the end of treatment. MASI declined from 20.42 ± 7.979 to 12.253 ± 7.37; and mMASI plummeted to 5.613 ± 3.98 from 10.673 ± 4.642 (p value <0.01). In group A, the difference in mean reduction of MASI and mMASI from baseline to end point was 6.572 ± 4.528 and 4.211 ± 2.647, respectively. In group B, the difference in mean reduction of both scores at the end of treatment reflected values of 8.167 ± 4.975(MASI) and 5.06 ± 2.977 (mMASI). No significant adverse effects were encountered in both treatment arms during the entire duration of study. Both TXA and PRP microinjections were found to be effective and safe therapeutic options for melasma, providing rapid and substantial improvement even when used as standalone therapies. Although PRP mesotherapy was found to be slightly better than intradermal TXA in our study, the results were not significant statistically.

Preferential stimulation of melanocytes by M2 macrophages to produce melanin through vascular endothelial growth factor

Post-inflammatory hyperpigmentation is a skin discoloration process that occurs following an inflammatory response or wound. As the skin begins to heal, macrophages first exhibit a proinflammatory phenotype (M1) during the early stages of tissue repair and then transition to a pro-healing, anti-inflammatory phenotype (M2) in later stages. During this process, M1 macrophages remove invading bacteria and M2 macrophages remodel surrounding tissue; however, the relationship between macrophages and pigmentation is unclear. In this study, we examined the effect of macrophages on melanin pigmentation using human induced pluripotent stem cells. Functional melanocytes were differentiated from human induced pluripotent stem cells and named as hiMels. The generated hiMels were then individually cocultured with M1 and M2 macrophages. Melanin synthesis decreased in hiMels cocultured with M1 macrophages but significantly increased in hiMels cocultured with M2 macrophages. Moreover, the expression of vascular endothelial growth factor was increased in M2 cocultured media. Our findings suggest that M2 macrophages, and not M1 macrophages, induce hyperpigmentation in scarred areas of the skin during tissue repair.

Sebocytes contribute to melasma onset

Melasma is a hyperpigmentary disorder with photoaging features, whose manifestations appear on specific face areas, rich in sebaceous glands (SGs). To explore the SGs possible contribution to the onset, the expression of pro-melanogenic and inflammatory factors from the SZ95 SG cell line exposed to single or repetitive ultraviolet (UVA) radiation was evaluated. UVA up-modulated the long-lasting production of α-MSH, EDN1, b-FGF, SCF, inflammatory cytokines and mediators. Irradiated SZ95 sebocyte conditioned media increased pigmentation in melanocytes and the expression of senescence markers, pro-inflammatory cytokines, and growth factors regulating melanogenesis in fibroblasts cultures. Cocultures experiments with skin explants confirmed the role of sebocytes on melanogenesis promotion. The analysis on sebum collected from melasma patients demonstrated that in vivo sebocytes from lesional areas express the UVA-activated pathways markers observed in vitro. Our results indicate sebocytes as one of the actors in melasma pathogenesis, inducing prolonged skin cell stimulation, contributing to localized dermal aging and hyperpigmentation.

Hair Graying Regulators Beyond Hair Follicle

Hair graying is an interesting physiological alteration associated with aging and certain diseases. The occurrence is due to depigmentation of the hair caused by depletion and dysfunction of melanocyte stem cells (MeSCs). However, what causes the depletion and dysfunction of MeSCs remains unclear. MeSCs reside in the hair follicle bulge which provides the appropriate niche for the homeostasis of various stem cells within hair follicle including MeSCs. In addition to local signaling from the cells composed of hair follicle, emerging evidences have shown that nerves, adipocytes and immune cells outside of hair follicle per se also play important roles in the regulation of MeSCs. Here, we review the recent studies on different cells in the MeSCs microenvironment beyond the hair follicle per se, discuss their function in regulating hair graying and potentially novel treatments of hair graying.

The Successful Treatment of Eyelid Intradermal Melanocytic Nevi (Nevus of Miescher)With the Dual-Wavelengths Copper Vapor Laser

Introduction: Surgical methods for removing eyelid nevus are associated with a risk of developing such side effects as scarring or loss of eyelashes. Although current laser modalities have shown promising results, eyelid laser surgery may cause skin discoloration and noticeable scarring. This study aims at evaluating the efficacy and safety of the dual-wavelengths copper vapor laser (CVL) treatment of eyelid intradermal nevus of Miescher (NM). Patients and Methods: We present three adult female patients with eyelid intradermal nevus treated with CVL. CVL settings were as follows: the average power of 0.6-0.8 W, under a power ratio of 3:2 at wavelengths of 511 nm and 578 nm, exposure time of 0.3 seconds, the light spot diameter of 1 mm. Results: The dual-wavelength CVL treatment of medium- and large-sized NM provides the complete removal of eyelid dome-like NM after one and two sessions with a month interval correspondingly. The duration of skin healing accounted for two weeks. Conclusion: The complete removal of eyelid NM lesions without side effects demonstrates the safety and efficacy of dual-wavelengths CVL in treating such skin lesions. This laser treatment mode of benign skin neoplasms seems promising for dermatologists and cosmetologists' clinical practice.

Melanogenesis and Melasma Treatment

Melanocytes are highly specialised dendritic cells that transfer melanin to keratinocytes in subcellular lysosome-like organelles called melanosomes, where melanin is synthesised and stored. Melanin is a complex pigment that provides colour and photoprotection to the skin, hair, and eyes of mammals. The regulation of melanogenesis includes various mechanisms and factors including genetic, environmental, and endocrine factors. Knowledge of the pigmentation process is important not only to understand hyperpigmentation but also to design treatments and therapies to treat them. Whitening cosmetics with anti-melanogenesis activity are very popular. In the present manuscript, we review the mechanisms and the signalling pathways involved in skin pigmentation and we specifically focus on the alteration of melanogenesis that leads to melasma and results in hyperpigmentation. Finally, current therapies and treatments including topical, oral, and phototherapies are discussed and described, with a special emphasis on the cosmetics’ action.

Experimental Models to Study Skin Wound Healing with a Focus on Angiogenesis

A large number of models are now available for the investigation of skin wound healing. These can be used to study the processes that take place in a phase-specific manner under both physiological and pathological conditions. Most models focus on wound closure, which is a crucial parameter for wound healing. However, vascular supply plays an equally important role and corresponding models for selective or parallel investigation of microcirculation regeneration and angiogenesis are also described. In this review article, we therefore focus on the different levels of investigation of skin wound healing (in vivo to in virtuo) and the investigation of angiogenesis and its parameters.

The pathogenesis of melasma and implications for treatment

BACKGROUND

Melasma is a complex and poorly understood disorder, with high rates of treatment failure and recurrences.

OBJECTIVES

We aimed to review the current knowledge of the pathogenesis of melasma and apply this knowledge to clinical implications on relevant therapeutic interventions.

METHODS

A systematic PubMed search was performed using the search term "((melasma[Text Word]) OR facial melanosis[Text Word]) AND (pathogenesis OR causality[MeSH Terms])" for articles published between 1990 and 2020. Included articles were then evaluated by two authors and assessed for relevant pathomechanistic pathways, after which they were divided into groups with minimal overlap. We then reviewed current treatment modalities for melasma and divided them according to the involved pathomechanistic pathway.

RESULTS

A total of 309 search results were retrieved among which 76 relevant articles were identified and reviewed. Five main pathomechanisms observed in melasma were identified: (1) melanocyte inappropriate activation; (2) aggregation of melanin and melanosomes in dermis and epidermis; (3a) increased mast cell count and (3b) solar elastosis; (4) altered basement membrane; and (5) increased vascularization. Treatment modalities were then divided based on these five pathways and detailed in 6 relevant tables.

CONCLUSION

The pathophysiology of melasma is multifactorial, resulting in treatment resistance and high recurrence rates. This wide variety of pathomechanisms should ideally be addressed separately in the treatment regimen in order to maximize results.

Alterations of the pigmentation system in the aging process

Human skin aging is a natural phenomenon that results from continuous exposure to intrinsic (time, genetic factors, hormones) as well as extrinsic factors (UV exposure, pollution, tobacco). In areas that are frequently exposed to the sun, photoaging blends with the process of intrinsic aging, resulting in an increased senescent cells number and consequently accelerating the aging process. The severity of photodamage depends on constitutional factors, including skin phototype (skin color, tanning capacity), intensity, and duration of sunlight/UV exposure. Aging affects nearly every aspect of cutaneous biology, including pigmentation. Clinically, the phenotype of age pigmented skin has a mottled, uneven color, primarily due to age spots, with or without hypopigmentation. Uneven pigmentation might be attributed to the hyperactivation of melanocytes, altered distribution of pigment, and turnover. In addition to direct damage to pigment-producing cells, photodamage alters the physiological crosstalk between keratinocytes, fibroblasts, endothelial cells, and melanocytes responsible for natural pigmentation homeostasis. Interestingly, age-independent diffuse expression of senescence-associated markers in the dermal and epidermal compartment is also associated with vitiligo, suggesting that premature senescence plays an important role in the pathology.

Novel Chemically Modified Curcumin (CMC) Analogs Exhibit Anti-Melanogenic Activity in Primary Human Melanocytes

Hyperpigmentation is a dermatological condition characterized by the overaccumulation and/or oversecretion of melanin pigment. The efficacy of curcumin as an anti-melanogenic therapeutic has been recognized, but the poor stability and solubility that have limited its use have inspired the synthesis of novel curcumin analogs. We have previously reported on comparisons of the anti-melanogenic activity of four novel chemically modified curcumin (CMC) analogs, CMC2.14, CMC2.5, CMC2.23 and CMC2.24, with that of parent curcumin (PC), using a B16F10 mouse melanoma cell model, and we have investigated mechanisms of inhibition. In the current study, we have extended our findings using normal human melanocytes from a darkly pigmented donor (HEMn-DP) and we have begun to study aspects of melanosome export to human keratinocytes. Our results showed that all the CMCs downregulated the protein levels of melanogenic paracrine mediators, endothelin-1 (ET-1) and adrenomedullin (ADM) in HaCaT cells and suppressed the phagocytosis of FluoSphere beads that are considered to be melanosome mimics. All the three CMCs were similarly potent (except CMC2.14, which was highly cytotoxic) in inhibiting melanin production; furthermore, they suppressed dendricity in HEMn-DP cells. CMC2.24 and CMC2.23 robustly suppressed cellular tyrosinase activity but did not alter tyrosinase protein levels, while CMC2.5 did not suppress tyrosinase activity but significantly downregulated tyrosinase protein levels, indicative of a distinctive mode of action for the two structurally related CMCs. Moreover, HEMn-DP cells treated with CMC2.24 or CMC2.23 partially recovered their suppressed tyrosinase activity after cessation of the treatment. All the three CMCs were nontoxic to human dermal fibroblasts while PC was highly cytotoxic. Our results provide a proof-of-principle for the novel use of the CMCs for skin depigmentation, since at low concentrations, ranging from 5 to 25 µM, the CMCs (CMC2.24, CMC2.23 and CMC2.5) were more potent anti-melanogenic agents than PC and tetrahydrocurcumin (THC), both of which were ineffective at melanogenesis at similar doses, as tested in HEMn-DP cells (with PC being highly toxic in dermal fibroblasts and keratinocytes). Further studies to evaluate the efficacy of CMCs in human skin tissue and in vivo studies are warranted.

A novel BLOC1S5-related HPS-11 patient and zebrafish with bloc1s5 disruption

Hermansky-Pudlak Syndrome (HPS) cases present with a variable degree of OCA and bleeding tendency. HPS is categorized into eleven types based on eleven causative genes, and disease severity varies among different types. By whole-exome sequencing performed on a family trio and Sanger sequencing of candidate variants, we identified a novel homozygous variant (NM_201280.3: c.181delC, p.Val61*) in BLOC1S5 in the patient who presents OCA and mild bleeding diathesis, and his healthy parents are heterozygous carriers. The variant can be considered pathogenic based on the guideline American College of Medical Genetics and Genomics, and the patient is proposed to be affected with HPS-11. In this study, we also explored bloc1s5 in zebrafish. bloc1s5 mRNA can be detected during early development of zebrafish. bloc1s5 knockdown zebrafish present with retinal hypopigmentation, thrombocytes loss and pericardial edema, and dll4/notch1 signaling and vascular integrity signaling are down-regulated at mRNA level in bloc1s5 morphants. The data from the first HPS-11 patient in Chinese population expand phenotypic and genotypic spectrum of HPS-11. Disruption of bloc1s5 in zebrafish recapitulates HPS-11-like phenotypes, and the potential signaling pathways associated with bloc1s5 are proposed. Altogether, this study may facilitate genetic counseling of HPS and investigation about BLOC1S5.

Treatment of Congenital Melanocytic Nevi With a Dual-Wavelengths Copper Vapor Laser: A Case Series

Introduction: Congenital melanocytic nevus (CMN) is a severe challenge for dermatology. This pigmented skin lesion is undesirable for patients because of its localization in open areas of the body. Various visible and near-infrared laser systems and intense pulsed light (IPL) sources have been applied for CMN treatment. However, post-traumatic hyperpigmentation, structural changes, atrophy, and scarring due to non-specific thermal damage have been observed. Many patients have shown recurrence after treatment. Therefore, it highlights the need for testing new laser modalities for the management of CMN. Methods: Two adult II Fitzpatrick phototype patients (a 55-year-old male and a 30-year-old female) with middle-sized facial CMN (on the forehead and lower eyelid) are presented. All patients were treated with dual-wavelength copper vapor laser (CVL) radiation at 511 nm and 578 nm wavelengths with a power ratio of 3:2. The average power was 0.7-0.85 W with an exposure time of 0.3 seconds. The spot size amounted to 1 mm. Results: Both patients showed complete resolution of CMN after CVL treatments. CMN became crusted within a few days after the laser treatment and peeled off within seven days. No recurrences were observed during the follow-up period up to 24 months. Conclusion: The middle-sized CMN can be successfully treated with dual-wavelength CVL radiation.

The Vascular Component of Melasma: A Systematic Review of Laboratory, Diagnostic, and Therapeutic Evidence

BACKGROUND

Melasma is a common acquired disorder of hyperpigmentation, classically manifesting as symmetric brown patches on the face. Although the exact pathogenesis is not fully understood, vascular abnormalities have been implicated in melasma.

OBJECTIVE

To evaluate the laboratory and clinical evidence regarding the safety and efficacy of antivascular agents for the treatment of melasma.

METHODS

A systematic review of PubMed, EMBASE, and Cochrane was conducted on May 13, 2020, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Original research articles investigating the role of vascularity and/or evaluating the use of antivascular therapeutics in melasma were included. Clinical recommendations were based on the American College of Physicians guidelines.

RESULTS

A total of 34 original research articles as follows were identified: 4 laboratory studies, 15 diagnostic studies, and 15 therapeutic studies.

CONCLUSION

There is promising evidence supporting the use of tranexamic acid and laser/light therapies to treat the vascular component of melasma, and more rigorous clinical trials are needed to validate their efficacy. Clinicians may consider treatment with one or more antivascular therapeutics in patients with melasma. Further research is warranted to characterize the role of cutaneous vascularization in melasma and may provide insights for novel therapies.

Treatment of palpebral melanocytic nevi with a dual-wavelengths copper vapor laser

Acquired melanocytic nevi in aesthetically significant areas, especially palpebral nevi (PN), are becoming a frequent reason for patients to seek dermatologists. Surgical methods for removal of PN are reported to be associated with the risk of such side effects as scars and loss of eyelashes. Aim of the study. To evaluate the efficacy of the removal of PN on the eyelid area with dual-wavelength radiation of a copper vapor laser (CVL). Patients and methods. Laser removal of medium and large-sized PN (up to 10 mm) was performed in three fair-skin female patients. The procedures were carried out at an average CVL radiation power of 0.60.8 W, at a 3:2 ratio of radiation powers at wavelengths of 511 nm and 578 nm, exposure duration 0.3 s, light spot diameter 1 mm. The treatment was carried out during one session. Results. Removal of PN with dual-wavelength CVL radiation allowed achieving a significant lightening and reduction of the involved area, without scars. The skin healing after the procedure lasted 2 weeks. Conclusion. The high efficacy of the PN removing in the eyelid area using the dual-wavelength CVL radiation allows the introduction of this approach into dermatologists and cosmetologists clinical practice.

Treatment of palpebral melanocytic nevi with a dual-wavelengths copper vapor laser

Acquired melanocytic nevi in aesthetically significant areas, especially palpebral nevi (PN), are becoming a frequent reason for patients to seek dermatologists. Surgical methods for removal of PN are reported to be associated with the risk of such side effects as scars and loss of eyelashes. Aim of the study. To evaluate the efficacy of the removal of PN on the eyelid area with dual-wavelength radiation of a copper vapor laser (CVL). Patients and methods. Laser removal of medium and large-sized PN (up to 10 mm) was performed in three fair-skin female patients. The procedures were carried out at an average CVL radiation power of 0.60.8 W, at a 3:2 ratio of radiation powers at wavelengths of 511 nm and 578 nm, exposure duration 0.3 s, light spot diameter 1 mm. The treatment was carried out during one session. Results. Removal of PN with dual-wavelength CVL radiation allowed achieving a significant lightening and reduction of the involved area, without scars. The skin healing after the procedure lasted 2 weeks. Conclusion. The high efficacy of the PN removing in the eyelid area using the dual-wavelength CVL radiation allows the introduction of this approach into dermatologists and cosmetologists clinical practice.

FGIN-1-27 Inhibits Melanogenesis by Regulating Protein Kinase A/cAMP-Responsive Element-Binding, Protein Kinase C-β, and Mitogen-Activated Protein Kinase Pathways

FGIN-1-27 is a synthetic mitochondrial diazepam binding inhibitor receptor (MDR) agonist that has demonstrated pro-apoptotic, anti-anxiety, and steroidogenic activity in various studies. Here we report, for the first time, the anti-melanogenic efficacy of FGIN-1-27 in vitro and in vivo. FGIN-1-27 significantly inhibited basal and α-melanocyte-stimulating hormone (α-MSH)-, 1-Oleoyl-2-acetyl-sn-glycerol (OAG)- and Endothelin-1 (ET-1)-induced melanogenesis without cellular toxicity. Mushroom tyrosinase activity assay showed that FGIN-1-27 did not directly inhibit tyrosinase activity, which suggested that FGIN-1-27 was not a direct inhibitor of tyrosinase. Although it was not capable of modulating the catalytic activity of mushroom tyrosinase in vitro, FGIN-1-27 downregulated the expression levels of key proteins that function in melanogenesis. FGIN-1-27 played these functions mainly by suppressing the PKA/CREB, PKC-β, and MAPK pathways. Once inactivated, it decreased the expression of MITF, tyrosinase, TRP-1, TRP-2, and inhibited the tyrosinase activity, finally inhibiting melanogenesis. During in vivo experiments, FGIN-1-27 inhibited the body pigmentation of zebrafish and reduced UVB-induced hyperpigmentation in guinea pig skin, but not a reduction of numbers of melanocytes. Our findings indicated that FGIN-1-27 exhibited no cytotoxicity and inhibited melanogenesis in both in vitro and in vivo models. It may prove quite useful as a safer skin-whitening agent.

Molecular Plasticity in Animal Pigmentation: Emerging Processes Underlying Color Changes

Animal coloration has been rigorously studied and has provided morphological implications for fitness with influences over social behavior, predator–prey interactions, and sexual selection. In vertebrates, its study has developed our understanding across diverse fields ranging from behavior to molecular biology. In the search for underlying molecular mechanisms, many have taken advantage of pedigree-based and genome-wide association screens to reveal the genetic architecture responsible for pattern variation that occurs in early development. However, genetic differences do not provide a full picture of the dynamic changes in coloration that are most prevalent across vertebrates at the molecular level. Changes in coloration that occur in adulthood via phenotypic plasticity rely on various social, visual, and dietary cues independent of genetic variation. Here, I will review the contributions of pigment cell biology to animal color changes and recent studies describing their molecular underpinnings and function. In this regard, conserved epigenetic processes such as DNA methylation play a role in lending plasticity to gene regulation as it relates to chromatophore function. Lastly, I will present African cichlids as emerging models for the study of pigmentation and molecular plasticity for animal color changes. I posit that these processes, in a dialog with environmental stimuli, are important regulators of variation and the selective advantages that accompany a change in coloration for vertebrate animals.

Treatment of сongenital melanocytic nevus in infants and children by a dual-wavelengths copper vapor laser

Introduction.Congenital melanocytic nevus (CMN) is detected at birth or shortly after birth in 1% of infants. The localization of CMN in aesthetically significant areas causes a decline in child self-esteem and causes concern for his parents. Surgical excision of skin areas with CMN is associated with an increased risk of cosmetic side effects and is often followed by long-term stress conditions after the invasive intervention. Aim of the study.To evaluate the efficacy of the CMN removal in infants, children and adolescents with the dual-wavelengths copper vapor laser (CVL) radiation. Patients and Methods.Medium-sized (up to 9 cm) single CMN was treated in nine fair-skinned patients: seven girls and two boys, aged from 2 months to 16 years. The procedures were carried out at an average CVL power of 0.61.0 W, with a power ratio of 3:2 at 511 nm and 578 nm wavelengths, and an exposure time of 0.20.3 s. Light spot diameter 1 mm. The treatment was carried out during 210 sessions with an interval of 12 months between sessions. Results.In children and adolescents, the treatment of CMN with CVL dual-wavelengths radiation made it possible to achieve significant clarification of the involved area without hypertrophic scars. The duration of the healing of the irradiated area lasted 23 weeks. Side effects were manifested with subtle skin atrophy. Conclusion.The high efficacy of CVL removal of medium-sized CMN in infants and children using the dual-wavelengths CVL radiation without pronounced side effects allows introducing such an approach in the clinical practice of pediatric dermatologists and cosmetologists.