Melasma: How hormones can modulate skin pigmentation

Components Analysis of San-Bai Decoction, and Its Pharmacodynamics and Mechanism on Preventing and Treating Melasma

ETHNOPHARMACOLOGICAL RELEVANCE

San-Bai Decoction (SBD) is a classic whitening prescription originally recorded in the 'Introduction to Medicine' of the Ming Dynasty. SBD has been known for invigorating Qi and blood, promoting spleen and stomach, whitening skin, and fading melasma. However, its pharmacodynamic material basis and specific mechanism remain unclear.

AIM OF THE STUDY

The aim of this study is to clarify the pharmacodynamic material basis of SBD and its mechanism of removing melasma.

MATERIALS AND METHODS

The positive and negative ion mass spectrum data of SBD extract were collected by UHPLC-Q-Exactive Orbitrap MS/MS, imported into Compound Discoverer (CD) 3.1 software, matched through the online database, and manually checked. Finally, the in vitro chemical components of SBD were classified. Similarly, the mass spectrum data of SBD in the serum of normal rats and melasma model rats were also analyzed by CD 3.1 software. The in vitro identified Compound file of SBD was imported into the Expected Compounds and the Generate Expected Compounds project was selected. The SBD compounds were then chosen under the Compound Section. All phase I and II reaction types related to SBD components were selected, and the metabolic platform of CD 3.1 software was utilized to process the results and obtain possible metabolites. The metabolites were scored and products with high scores were subsequently screened. According to literature comparison, the final metabolites of SBD in both normal rats and melasma model rats were determined and comprehensively analyzed. The Melasma model rats were constructed through intramuscular injection of progesterone and ultraviolet radiation B (UVB) irradiation. The preventing and treating effect of SBD on melasma were evaluated by regulating inflammation, epidermal collagen content, and oxidative stress. Additionally, the effect of SBD on the Phosphatidylinositol 3-kinase (PI3K)/Protein kinase B (Akt)/Glycogen synthase kinase 3β (GSK3β) pathway was investigated through Western blot (WB) to explore its underlying mechanism on whitening and removing melasma efficacy.

RESULTS

Ultimately, 94 components were identified in SBD, including 41 flavonoids, 27 organic acids, and 9 glycosides, 3 terpenoids, 2 amides, 2 aldehydes, 1 phenylpropanoid and 9 other compounds. In the blood of normal rat group, a total of 24 prototype components and 61 metabolites were identified. Similarly, there were19 prototype components and 44 metabolites identified from the blood of melasma model rats. Pharmacodynamic experiment results indicated that SBD effectively reduced the incidence of melasma, prevent the loss of epidermal collagen, and elevate the activity of superoxide dismutase and decrease the malondialdehyde content in both liver and skin. Interestingly, the WB results demonstrated that SBD effectively activated PI3K/Akt/GSK3β pathway, and down-regulated the expression of melanin-related proteins.

CONCLUSIONS

For the first time, the components of SBD extracts, and its prototype components and metabolites in the blood of normal rats and melasma model rats were successfully identified by high-resolution liquid chromatography-mass spectrometry with CD software. Additionally, the differences of in vivo components of SBD between normal rats and melasma model rats were analyzed. The preventive and therapeutic effect of SBD on melasma was verified in the melasma model rats induced by progesterone and UVB irradiation, and its mechanism was related to activating PI3K/Akt/GSK3β pathway and downregulating the expression of melanin-related proteins. These results provide an experimental foundation for further research on the pharmacodynamic substance basis and pharmacodynamic mechanism of SBD, as well as developing new anti-melasma formula with SBD.

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.

Preparation of paeoniflorin-glycyrrhizic acid complex transethosome gel and its preventive and therapeutic effects on melasma

Paeoniflorin (PF) and glycyrrhizic acid (GL) have skin beautifying effects of anti-inflammation, anti-oxidation, inhibition of melanin formation, and reduction of skin pigmentation. To improve the transdermal permeability of PF and GL in transdermal drug delivery system (TDDS) and enhance their anti-melasma efficacy, PF-GL transethosome (PF-GL-TE) was prepared by ethanol injection method, and finally gelled with carbomer-940 to form PF-GL-TE gel. Consequently, the obtained PF-GL-TE is small and uniform, with an average particle size and a PDI value of about 167.9 nm and 0.102. PF-GL-TE gel showed sustained release behavior and high transdermal permeability in vitro release and transdermal tests. Meanwhile, PF-GL-TE gel played significant preventive effects on melasma induced by progesterone injection and ultraviolet radiation B (UVB) irradiation. According to the results of H&E staining and Masson staining of rat skin, PF-GL-TE gel can alleviate the skin inflammation of and reduce the loss of collagen fibers of back skin in the melasma model rats. Compared with the PF-GL mixture gel, PF-GL-TE gel significantly attenuated the oxidative damage of liver and skin by increasing the activity of SOD and reducing the content of MDA. The results of Western blot showed that PF-GL-TE gel might down-regulate melanin-related proteins expressions of MITF/TYR/TRP1 and TRP2 to prevent and treat melasma. These findings indicate that PF-GL-TE gel is an effective TDDS for delivering PF and GL into the skin, providing a promising preparation for effective prevention and treatment of melasma.

Young Chinese female body skin pigmentation map: A pilot study

BACKGROUND

Most studies have discussed variations in facial skin colour based on age, gender, and anatomical site within a specific ethnic group. However, skin pigmentation on the body is also a concern for many people.

AIM

The aim of this study is to gather baseline data for Chinese young females, conduct a comprehensive assessment of body skin pigmentation, and create a body skin pigmentation map.

METHOD

Individual type angle (ITA°) was registered by CL 400 and melanin index (MI) was registered by MX 18 in 100 body points of 20 Chinese females. A total of 12,000 measurements were recorded.

RESULT

Our results showed significant differences among the symmetrical points on both sides of the body, including the clavicle, inner wrists, groin, inner ankle, elbow, armpit, waist side, the space between the thumb and index finger, instep, back shoulder, and popliteal space. Of all the points tested on the body, the points with the most severe skin pigmentation were the back of the neck, the heel, the elbow, and the popliteal space.

CONCLUSION

This is the first comprehensive study of skin pigmentation conducted on the human body. In young Chinese women, the points with the most severe skin pigmentation were the back of the neck, heels, elbows, and the popliteal space.

Proteomic Analysis of Two Different Methods to Induce Skin Melanin Deposition Models in Guinea Pigs

Objective

In this study, we analyzed the differential expression and key signaling pathways of proteins in the skin of guinea pigs with melanin deposition caused by two different modeling methods by utilizing proteomics techniques.

Methods

Guinea pig skin melanin deposition models were: (1) induced by ultraviolet (UV) irradiation alone (U group), (2) induced by UV combined with progesterone injection (P group), and guinea pigs treated without any treatment were used as blank group (B group). H&E staining and Masson staining were used to observe the extent of skin damage and melanin deposition in guinea pigs. The differentially expressed proteins (DEPs) in the skin tissues of melanin-deposited guinea pigs were screened by proteomic techniques, the functions of DEPs were analyzed, and a protein-protein interaction network (PPI) was constructed.

Results

There was a significant difference in grayscale between the U and P groups of guinea pig skin before and after modeling (P < 0.01). H&E and Masson staining showed that the U and P groups both exhibited incomplete keratinization of the stratum corneum, increased proliferation of epidermal cells with large nuclei and disordered arrangement, neovascularization of the dermis, and increased the number of melanin particles in the epidermis of the U and P groups of guinea pigs compared with the B group. Proteomics analysis showed that there were 171 DEPs between the U and P groups. These DEPs focused on biological processes such as fibrillar collagen trimer, extracellular matrix containing collagen proteins, metalloproteinase activity, and peroxidase activity.

Conclusion

The melanin pigmentation model induced solely by UV radiation negatively regulates biological processes such as extracellular matrix and collagen synthesis, while inducing significant skin photoaging. The combination of progesterone injections and UV radiation-induced melanin pigmentation model can cause abnormal protein expression in fatty acid and phospholipid metabolism, possibly being closer to the environment of melasma formation.

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.

Correlation analysis between gut microbiota characteristics and melasma

In recent years, many studies have shown that the gut microbiota can affect the occurrence and development of a variety of human diseases. A variety of skin diseases are related to the regulation of the gut-skin axis, such as psoriasis, atopic dermatitis, and acne. Gut microbial dysbiosis can promote the development of these diseases. The gut microbiota can affect estrogen metabolism, β-glucuronidase secreted by the gut microbiota can promote the reabsorption of estrogen by the gut, and estrogen is transported to other parts of the body through the circulatory system. The occurrence and development of melasma are closely related to abnormal metabolism of estrogen. The relationship between the structure of the gut microbiota and melasma remains unclear. Epidemiological surveys were conducted in patients with melasma and healthy subjects (control group) in this study. The feces were collected for 16S rRNA sequencing analysis of the gut microbiota. To compare the similarities and differences in species diversity of the gut microbiota between these two groups, we calculated the α-diversity and β-diversity indices and analyzed the differences between them. We found that the abundance of Collinsella spp., Actinomyces spp. (belonging to Actinobacteria), Parabacteroides spp., Bacteroides spp., Paraprevotella spp. (belonging to Bacteroidetes), Blautia spp., and Roseburia spp. (belonging to Firmicutes) in the melasma group were significantly different compared with that in the healthy group. The largest difference was found in Actinobacteria (p < 0.05), and there were also significant differences in the abundance of Coriobacteriia, Actinobacteria, Coriobacteriales, Coriobacteriaceae, and Collinsella spp. between the two groups (all p < 0.05). Many of these differences in the microbiota were closely related to the production of β-glucuronidase and the regulation of estrogen synthesis or metabolism. Changes in the gut microbiota structure and the biological effects of Collinsella spp. in the microbiota in patients with melasma can play an important role in the occurrence and development of melasma by affecting the body's estrogen metabolism. This study provides a theoretical basis and experimental data reference for future studies on the relationship between the gut microbiota and melasma, and may be helpful for the prevention and treatment of melasma.

Amorphigenin from Amorpha fruticosa L. Root Extract Induces Autophagy-Mediated Melanosome Degradation in mTOR-Independent- and AMPK-Dependent Manner

In this study, we investigated the depigmentation effect of Amorpha fruticosa L. root extract (RE), an herbal medicine. A. fruticosa RE significantly induced depigmentation in α-MSH-treated B16F10 cells at noncytotoxic concentrations. Further, the RE decreased the protein levels of the melanosomal proteins Tyr and Pmel without decreasing their transcript levels. We found that MG132, a proteasome complex inhibitor, was unable to rescue the protein levels, but PepA/E-64D (a lysosomal enzyme inhibitor), 3-MA (a representative autophagy inhibitor), and ATG5 knockdown effectively rescued the protein levels and inhibited the depigmentation effect following RE treatment. Among rotenoids, amorphigenin composed in the RE was identified as a functional chemical that could induce depigmentation; whereas rapamycin, an mTOR inhibitor and a nonselective autophagy inducer, could not induce depigmentation, and amorphigenin effectively induced depigmentation through the degradation of melanosomal proteins. Amorphigenin activated AMPK without affecting mTOR, and knockdown of AMPK offset the whitening effect through degradation of melanosome proteins by amorphigenin. Results from this study suggested that amorphigenin can induce degradation of the melanosome through an AMPK-dependent autophagy process, and has the potential to be used as a depigmentation agent for the treatment of hyperpigmentation.

Efficacy of Cysteamine and Methimazole in Treating Melasma A Comparative Narrative Review

Melasma is a chronic and acquired pigmentary condition that primarily affects women and undermines patient satisfaction and confidence. Melasma mostly affects females, accounting for 90% of all cases. It affects people of all races, particularly those with skin types IV and V who live in areas with lots of UV radiation. According to the studies, Melasma lesions are seen throughout the face in centrofacial, malar, and mandibular patterns. Melasma lesions on the forehead, cheeks, nose, upper lip, and/or chin are the most prevalent centrofacial pattern. Melasma lesions can also be detected along the periorbital area, especially in Asian people. Melasma is notably resistant to treatment, with many patients experiencing only temporary relief and relapses. Combining therapies that target numerous pathologic components, including photodamage, inflammation, aberrant vascularity, and abnormal pigmentation, generally results in the most dramatic therapeutic improvements. Treatments for dark circles include topical depigmenting medicines like hydroquinone, kojic acid, azelaic acid, and topical retinoic acid, and physical treatments such as chemical peels, surgical adjustments, and laser therapy. The objective of therapy should be to figure out what's causing the hyperpigmentation and what's contributing to it. This article provides an overview of melasma therapies and the efficacy of methimazole and cysteamine for melasma therapy.

Self-applied topical interventions for melasma: a systematic review and meta-analysis of data from randomized, investigator-blinded clinical trials

BACKGROUND

Melasma is a frequent dermatological condition. Although its relevance as a skin condition is primarily of cosmetic nature, it may affect the patients' well-being and quality of life. A broad range of treatment options is available, which makes it difficult to choose the most appropriate treatment.

OBJECTIVES

To summarise and critically appraise evidence from investigator-blinded RCTs on the efficacy and safety of self-applied topical interventions for melasma.

METHODS

We systematically searched MEDLINE and Cochrane CENTRAL for RCTs on topical, self-administered interventions for patients diagnosed with melasma. Eligibility was limited to RCTs that explicitly stated in their methods section (1) how they generated the random allocation sequence, and (2) that the study outcome assessor was blinded towards the participants' group allocation. Outcomes of interest included evaluator-assessed clinical scores (e.g., melasma area and severity index, MASI), quality of life, and patient-reported outcomes as well as safety outcomes. The study findings were meta-analysed, pooling data from studies on the same comparisons, if this was possible. We assessed confidence in the effect estimates using the GRADE approach.

RESULTS

Our searches yielded 1,078 hits. We included 36 studies reporting on 47 different comparisons of interventions. These included medical treatments such as 'triple combination cream' (TCC), over-the-counter cosmetic and herbal products, as well as sun creams covering different light spectra. Pooling data was possible for only two comparisons (topical tranexamic acid (TXA) vs. hydroquinone (HQ) and cysteamine vs. placebo). Direct comparisons were available for a variety of interventions; however, the reported outcomes varied largely. Overall, our confidence in the effect estimates ranged from very low to high.

CONCLUSION

Our findings indicate that TCC and its individual components HQ and tretinoin are effective in lightening melasma. Besides these established self-applied treatment options, we identified further medical as well as promising cosmetic and herbal product treatment approaches. Furthermore, evidence suggests that using broad-spectrum sunscreen covering both the visible and UV-light spectrum enhances the treatment efficacy of HQ. However, with mostly small RCTs comparing treatments directly, using a broad range of outcomes, further research is needed to draw conclusions about which treatment is most effective.

An Open-Label Study Assessing the Efficacy and Tolerability of a Skincare Regimen in Subjects of Different Ethnicities with Moderate-to-Severe Hyperpigmentation

Background

Hyperpigmentation is a common cosmetic concern that significantly impacts self‐esteem. A skincare regimen has been developed to improve the appearance, tone, texture, and luminosity of subjects with facial hyperpigmentation (Even Up^® Hyperpigmentation Regimen; Colorescience, Inc., Carlsbad, CA).

Aims

The objective of this open‐label trial was to assess the efficacy and tolerability of this regimen for treating facial hyperpigmentation.

Patients/Methods

Subjects with moderate‐to‐severe facial hyperpigmentation (N = 33) were randomized to those not using prescription, advanced or physician‐dispensed skin care products (Group A, n = 23) and those currently using prescription, advanced or physician‐dispensed skincare products for facial hyperpigmentation (Group B, n = 10). Both groups were provided three skincare products comprising the hyperpigmentation regimen and instructions for use. Subjects were evaluated at baseline and Weeks 2, 4, 8 and 12.

Results

The overall median (range) baseline MASI score at baseline was 9.0 (2, 31), decreasing by 0.0 (−7, 0) points at Week 2 (p = 0.002), 0.6 (−8, 0) points at Week 4 (p < 0.0001), 1.5 (−16, 0) points by Week 8 (p < 0.0001) and 2.4 (−20, 0) points at Week 12 (p < 0.0001). At Week 12, the overall median improvement in MASI score was 26% and higher for Group B (32% vs. 22%). By Week 2, subjects reported lighter, less noticeable brown spots (76%), brighter, more luminous skin (88%), more even skin tone (67%), and healthier look and feel (85%). Improvements continued throughout the study. No adverse events were observed or reported.

Conclusions

This regimen addresses facial hyperpigmentation and protects skin against the damaging effects of ultraviolet and high energy visible light (HEV). It is safe to use on all skin types and tones.

Role of Amine Neurotransmitters and Their Receptors in Skin Pigmentation: Therapeutic Implication

Skin pigmentation can occur due to increased melanin, including melanocyte proliferation, melanin biosynthesis, or melanocyte migration. There are many factors that influence the melanin production process, but the role of neurotransmitters in this process is still unclear. We found that histamine and serotonin influence the different stages of melanogenesis and melanogenesis, which increase melanogenesis. Since then, several related papers have been published, and from these papers, it has been recognised that the role of neurotransmitters in skin-pigment-related diseases needs to be summarised. By introducing the role of neurotransmitters in the regulation of various pigment disorders, including vitiligo and melasma, through this review, many researchers can be expected to try to apply neurotransmitter-related agonists and antagonists as treatments for skin pigment disorders.