Microbial community profiling shows dysbiosis in the lesional skin of Vitiligo subjects

Beyond skin deep: exploring the complex molecular mechanisms and holistic management strategies of vitiligo

Vitiligo is a multifactorial skin disorder characterized by the progressive loss of pigmentation due to the destruction of melanocytes, affecting 0.5-2% of the global population. This condition not only impacts physical appearance but also has profound psychosocial effects on patients. In this review, various aspects of vitiligo are explored, including its clinical forms, epidemiology, and underlying mechanisms. Advances in research have identified key molecular pathways, such as Wnt/β-Catenin, JAK-STAT, and AhR signaling, which are essential for melanocyte survival and immune regulation. These pathways provide valuable insights into the disease's progression and potential treatment targets. Furthermore, the role of microbial imbalances in the gut and skin microbiomes, stress-related factors, and nutritional deficiencies in influencing the onset and progression of vitiligo is investigated. The potential of herbal treatments to stimulate repigmentation is also discussed. By presenting a comprehensive overview, this review aims to deepen the understanding of vitiligo's complex pathology and foster the development of effective therapeutic strategies to enhance patient care.

Microbiome and Postbiotics in Skin Health

The skin microbiome, a diverse and dynamic ecosystem of microorganisms, plays a pivotal role in maintaining skin health by interacting with skin cells, immune components, and structural barriers. It is essential for skin homeostasis, immune defense, and protection against pathogenic colonization. Dysbiosis in the microbiome has been implicated in numerous dermatological conditions, including acne, eczema, psoriasis, and rosacea. Acne, the most prevalent skin condition, affects up to 85% of individuals at some point in their lives, while eczema and psoriasis impose significant public health and economic burdens. The composition of the skin microbiome varies across skin types and anatomical sites, with sebaceous, moist, and dry areas fostering distinct microbial communities. Emerging therapeutic strategies such as microbiome-targeted treatments offer novel avenues for addressing skin diseases. Among these approaches, postbiotics have gained significant attention for their safety and efficacy. Unlike probiotics, postbiotics are non-viable microbial cells or their metabolites, which reduce safety concerns while providing functional benefits such as UV protection and wound healing. This review consolidates current insights into the role of the skin microbiome in health and disease, emphasizing postbiotics as a promising therapeutic strategy by exploring the clinical and commercial potential of microbiome-based treatments, particularly postbiotics, and their ability to redefine dermatological care and improve patient outcomes.

Characterization of Gut Microbiota in Patients with Active Spreading Vitiligo Based on Whole-Genome Shotgun Sequencing

Vitiligo is an autoimmune skin disease with a significant psychological burden and complex pathogenesis. While genetic factors contribute approximately 30% to its development, recent evidence suggests a crucial role of the gut microbiome in autoimmune diseases. This study investigated differences in gut microbiome composition and metabolic pathways between active spreading vitiligo patients and healthy controls using shotgun whole-genome sequencing in a Korean cohort. Taxonomic profiling reveals distinct characteristics in microbial community structure, with vitiligo patients showing an imbalanced proportion dominated by Actinomycetota and Bacteroidota. The vitiligo group exhibited significantly reduced abundance of specific species including Faecalibacterium prausnitzii, Faecalibacteriumduncaniae, and Meamonas funiformis, and increased Bifidobacterium bifidum compared to healthy controls. Metabolic pathway analysis identified significant enrichment in O-glycan biosynthesis pathways in vitiligo patients, while healthy controls showed enrichment in riboflavin metabolism and bacterial chemotaxis pathways. These findings provide new insights into the gut-skin axis in vitiligo pathogenesis and suggest potential therapeutic targets through microbiota modulation.

Vitiligo and the microbiome of the gut and skin: a systematic review

Vitiligo is a chronic autoimmune skin condition characterized by depigmentation due to the destruction of melanocytes. Recent research has identified potential links between vitiligo and alterations in both the gut and skin microbiomes. This systematic review aims to explore these microbiome changes and their potential role in the onset and progression of vitiligo. A comprehensive search of the PubMed, Medline (OVID), and Web of Science databases was conducted to identify studies examining the gut and/or skin microbiota in vitiligo patients. A total of six studies were included in the qualitative analysis. Data extracted included study type, patient demographics, microbiome sampling methods, bacterial diversity, and bacterial ratios. The studies were assessed using the Methodological Index for Non-Randomized Studies (MINORS) scale. The results revealed inconsistent findings regarding microbial diversity in vitiligo patients. Some studies observed decreased α-diversity in the gut microbiome, while others found an increase, particularly in patients with longer disease duration. An increased Firmicutes-to-Bacteroidetes ratio (higher levels of Firmicutes bacteria compared to Bacteroidetes) was noted in several studies, suggesting a dysbiotic gut microbiome. In the skin microbiome, similar trends of dysbiosis were observed, with alterations in bacterial diversity between lesional and non-lesional skin. The findings indicate that gut and skin microbiome changes may play a role in the pathogenesis of vitiligo. However, the data remain inconclusive due to variability in methodologies and sample sizes. Further research is needed to elucidate the clinical relevance of microbiome alterations in vitiligo, with a focus on controlling external factors such as diet and lifestyle.

Analysis of the Genomes and Adaptive Traits of Skermanella cutis sp. nov., a Human Skin Isolate, and the Type Strains Skermanella rosea and Skermanella mucosa

The genus Skermanella comprises important soil bacteria that are often associated with the crop rhizospheres, but its physiological traits remain poorly understood. This study characterizes Skermanella sp. TT6T, isolated from human skin, with a focus on its metabolic and environmental adaptations. Genome sequencing and phylogenomic analyses revealed that the strain TT6T is most closely related to S. rosea M1T, with average nucleotide identity and digital DNA-DNA hybridization values of 94.14% (±0.5%) and 64.7%, respectively. Comparative genomic analysis showed that the strains TT6T, S. rosea M1T and S. mucosa 8-14-6T share the Calvin cycle, and possess photosynthetic genes associated with the purple bacteria-type photosystem II. The strains TT6T and S. rosea M1T exhibited growth in a nitrogen-free medium under microaerobic conditions, which were generated in test tubes containing 0.1% soft agar. Under these conditions, with nitrate as a nitrogen source, S. rosea M1T formed gases, indicating denitrification. Strain TT6T also contains gene clusters involved in trehalose and carotenoid biosynthesis, along with salt-dependent colony morphology changes, highlighting its adaptive versatility. Genomic analyses further identified pathways related to hydrogenase and sulfur oxidation. Phenotypic and chemotaxonomic traits of strain TT6T were also compared with closely related type strains, confirming its genotypic and phenotypic distinctiveness. The new species, Skermanella cutis sp. nov., is proposed, with TT6T (=KCTC 82306T = JCM 34945T) as the type strain. This study underscores the agricultural and ecological significance of the genus Skermanella.

Bacillus Subtilis-Derived Exopolysaccharide Halts Depigmentation and Autoimmunity in Vitiligo

Vitiligo has a complex multifactorial etiology involving a T-cell-mediated autoimmune response to cutaneous melanocytes. Microbial dysbiosis has been assigned a contributing role in vitiligo etiology. Treating vitiligo can be a challenging task, and finding novel treatment approaches is crucial. In this study, we tested exopolysaccharides (EPSs) isolated from Bacillus subtilis as a microbiome-based therapy. Vitiligo-prone h3TA2 mice were treated by weekly intraperitoneal EPS injection for 18 weeks. Depigmentation was evaluated over time, measuring immune responses at end point. EPS treatment significantly limited the rate of depigmentation. The abundance of cutaneous T cells, specifically CD8+ cytotoxic T cells, was reduced, whereas regulatory T cells were more abundant in the skin of treated mice than in untreated mice. Moreover, EPS treatment was associated with increased numbers of splenic M2 macrophages, elevated splenic indoleamine 2,3-dioxygenase expression, and a systemic cytokine shift toward a type 2 pattern of cytokines. Importantly, splenocytes retrieved from EPS-treated mice were less responsive to cognate tyrosinase peptide, as demonstrated by limited release of IFN-γ and other inflammatory cytokines. In summary, EPS isolated from Bsubtilis interfered with T-cell-mediated depigmentation in the h3TA2 mouse model of vitiligo, suggesting that Bsubtilis EPS could serve as a novel treatment entity for vitiligo.

Characteristics and Differences in the Antler Velvet Microbiota During Regeneration

The skin surface has a complex and dynamic ecosystem inhabited by a diverse microbiota. The wound formed by antler velvet shedding can naturally achieve regenerative restoration, but the changes in microbial composition that occur during antler velvet regeneration are largely unknown. In this study, we analyzed the antler velvet microbiota of sika deer at 15 days (Half) and 30 days (Full) post-pedicle casting using 16S rRNA gene sequencing. A total of 2659 OTUs were identified, which were assigned to 26 phyla, 304 families, and 684 genera. The core microbiota of the two groups were mainly composed of Atopostipes spp., Corynebacterium spp., Burkholderia spp., Staphylococcus spp., and Paracoccus spp. In comparison with the Full group, the Shannon, Simpson, Ace, and Chao 1 indices were significantly decreased in the Half group (p < 0.05). Principal coordinate analysis showed that there were significant differences in the microbial community between the Half and Full groups based on Bray-Curtis dissimilarity, weighted Unifrac distance, and unweighted Unifrac distance (p < 0.05). The relative abundances of bacteria belonging to the genera Staphylococcus, Romboutsia_B, and Dietzia increased significantly in the Half group, while the abundances of bacteria belonging to the genera Atopostipes, Psychrobacter, and Faecousia increased significantly in the Full group (p < 0.05). Correlation analysis showed that the relative abundances of bacteria belonging to the genera Staphylococcus, Romboutsia_B, and Dietzia positively correlated with arginine and proline metabolism (p < 0.05). These findings demonstrate that antler velvet regeneration is accompanied by distinct changes in microbial composition and highlight the potential roles of key taxonomy in wound healing and tissue regeneration.

Aging-Induced Changes in Cutibacterium acnes and Their Effects on Skin Elasticity and Wrinkle Formation

Skin aging involves biomechanical changes like decreased elasticity, increased wrinkle formation, and altered barrier function. The skin microbiome significantly impacts this process. Here, we investigated the effects of decreased Cutibacterium acnes abundance and increase in other skin microorganisms on skin biomechanical properties in 60 healthy Koreans from Seoul, divided into younger (20-29 years) and older (60-75 years) groups. Metagenomic sequencing and skin assessments showed that the older group exhibited decreased C. acnes dominance and increased microbial diversity, correlating with reduced skin elasticity and increased wrinkles. In the younger age group, the enriched pathways included zeatin biosynthesis, distinct biotin metabolism pathways, and cofactor and vitamin metabolism in the younger age group, whereas pathways related to lipid metabolism, energy metabolism, and responses to environmental stressors, including UV damage and pollution, were enriched in the older group, according to functional analysis results. Network analysis indicated higher microbial connectivity in the younger group, suggesting a more stable community, whereas the older group's community displayed higher modularity, indicating more independent and specialized clusters. This study enhances our understanding of the impact of skin microbiome changes on skin aging, particularly the anti-aging effects of C. acnes. Future research should focus on the physiological mechanisms of skin microbiota on skin aging and explore therapeutic potentials to enhance skin health.

Mild atopic dermatitis is characterized by increase in non-staphylococcus pathobionts and loss of specific species

Atopic dermatitis is the most common inflammatory skin condition with a severe negative impact on patients' quality of life. The etiology of AD is complex and depends on age, genetics, the immune system, environmental factors, and the skin microbiome, with a key role for pathogenic Staphylococcus aureus in the development of severe AD. However, the composition of the skin microbiome in mild AD is understudied. Here, using metagenomic shallow shotgun sequencing, we showed that mild AD lesions did not show a significant difference in the diversity of the skin microbiome compared to samples from non-AD patients and that the relative abundance of S. aureus did not differ in these mild AD lesions. However, when we assessed other taxa, Mycobacterium ostraviense, Pedobacter panaciterrae_A and four Streptomyces species were identified with higher abundances in mild AD lesions and species of 15 genera were decreased in abundance. The highest fold decreases were observed for Paracoccus marcusii, Microbacterium lacticum, Micrococcus luteus, and Moraxella sp002478835. These microbiome compositional insights are a first step towards novel microbiome-based diagnostics and therapeutics for early intervention at the stage of mild AD and provide a path forward for the functional study of species involved in this often-overlooked patient population.

Topical antibiotics limit depigmentation in a mouse model of vitiligo

Oral neomycin administration impacts the gut microbiome and delays vitiligo development in mice, and topical antibiotics may likewise allow the microbiome to preserve skin health and delay depigmentation. Here, we examined the effects of 6-week topical antibiotic treatment on vitiligo-prone pmel-1 mice. Bacitracin, Neosporin, or Vaseline were applied to one denuded flank, while the contralateral flank was treated with Vaseline in all mice. Ventral depigmentation was quantified weekly. We found that topical Neosporin treatment significantly reduced depigmentation and exhibited effects beyond the treated area, while Bacitracin ointment had no effect. Stool samples collected from four representative mice/group during treatment revealed that Neosporin treatment aligned with reduced abundance of the Alistipes genus in the gut, while relevant changes to the skin microbiome at end point were less apparent. Either antibiotic treatment led to reduced expression of MR1, potentially limiting mucosal-associated invariant T-cell activation, while Neosporin-treated skin selectively revealed significantly reduced CD8+ T-cell abundance. The latter finding aligned with reduced expression of multiple inflammatory markers and markedly increased regulatory T-cell density. Our studies on favorable skin and oral antibiotic treatment share the neomycin compound, and in either case, microbial changes were most apparent in stool samples. Taken together, neomycin-containing antibiotic applications can mediate skin Treg infiltration to limit vitiligo development. Our study highlights the therapeutic potential of short-term antibiotic applications to limit depigmentation vitiligo.

Selective Depletion of Staphylococcus aureus Restores the Skin Microbiome and Accelerates Tissue Repair after Injury

Our skin is home to a diverse community of commensal microorganisms integral to cutaneous function. However, microbial dysbiosis and barrier perturbation increase the risk of local and systemic infection. Staphylococcus aureus is a particularly problematic bacterial pathogen, with high levels of antimicrobial resistance and direct association with poor healing outcome. Innovative approaches are needed to selectively kill skin pathogens, such as S aureus, without harming the resident microbiota. In this study, we provide important data on the selectivity and efficacy of an S aureus-targeted endolysin (XZ.700) within the complex living skin/wound microbiome. Initial cross-species comparison using Nanopore long-read sequencing identified the translational potential of porcine rather than murine skin for human-relevant microbiome studies. We therefore performed an interventional study in pigs to assess the impact of endolysin administration on the microbiome. XZ.700 selectively inhibited endogenous porcine S aureus in vivo, restoring microbial diversity and promoting multiple aspects of wound repair. Subsequent mechanistic studies confirmed the importance of this microbiome modulation for effective healing in human skin. Taken together, these findings strongly support further development of S aureus-targeted endolysins for future clinical management of skin and wound infections.

Vitis vinifera L. Leaf Extract, a Microbiota Green Ally against Infectious and Inflammatory Skin and Scalp Diseases: An In-Depth Update

The skin microbiota, with its millions of bacteria, fungi, and viruses, plays a key role in balancing the health of the skin and scalp. Its continuous exposure to potentially harmful stressors can lead to abnormalities such as local dysbiosis, altered barrier function, pathobiont overabundance, and infections often sustained by multidrug-resistant bacteria. These factors contribute to skin impairment, deregulation of immune response, and chronic inflammation, with local and systemic consequences. In this scenario, according to the needs of the bio-circular-green economy model, novel harmless strategies, both for regulating the diverse epidermal infectious and inflammatory processes and for preserving or restoring the host skin eubiosis and barrier selectivity, are requested. Vitis vinifera L. leaves and their derived extracts are rich in plant secondary metabolites, such as polyphenols, with antioxidant, anti-inflammatory, antimicrobial, and immunomodulatory properties that can be further exploited through microbe-driven fermentation processes. On this premise, this literature review aims to provide an informative summary of the most updated evidence on their interactions with skin commensals and pathogens and on their ability to manage inflammatory conditions and restore microbial biodiversity. The emerging research showcases the potential novel beneficial ingredients for addressing various skincare concerns and advancing the cosmeceutics field as well.

High α-diversity of skin microbiome and mycobiome in Japanese patients with vitiligo

BACKGROUND

Vitiligo is an acquired pigmentary disorder characterized by depigmented patches on the skin that majorly impact patients' quality of life. Although its etiology involves genetic and environmental factors, the role of microorganisms as environmental factors in vitiligo pathology remains under-researched.

OBJECTIVES

Our study explored the presence of characteristic bacterial and fungal flora in vitiligo-affected skin and investigated their potential roles in vitiligo pathogenesis.

METHODS

We sequenced bacterial 16S rRNA and the fungal ITS1 region from skin swabs collected at frequently affected sites, namely the forehead and back, of patients with vitiligo. We analyzed bacterial and fungal flora in lesional and non-lesional areas of patients with vitiligo compared with corresponding sites in age- and sex-matched healthy subjects.

RESULTS

Our findings revealed elevated α-diversity in both bacterial and fungal flora within vitiligo lesions compared with healthy controls. Notably, bacterial flora exhibited a distinctive composition in patients with vitiligo, and the proportional representation of Enterococcus was inversely correlated with the degree of vitiligo progression. Gammaproteobacteria, Staphylococcus spp., and Corynebacterium spp. were more abundant in vitiligo patients, with notable Staphylococcus spp. prevalence during the stable phase on the forehead. Conversely, the proportion of Malassezia sympodialis was lower and that of Malassezia globosa was higher in the progressive phase on the back of vitiligo patients.

CONCLUSION

Our study identified some characteristic bacterial and fungal groups associated with vitiligo activity and prognosis, highlighting the potential roles of microorganisms in pathogenesis and offering insights into personalized disease-management approaches.

Exploration of photoprotective and antibiotic activity of wild Polypodiaceae ferns from Costa Rica

Skin disorders affect millions of people all over the world. There are limited options to treat dermal illnesses such as vitiligo, psoriasis, and atopic dermatitis (eczema). Central American ferns are a potential source of bioactive metabolites against those diseases. Currently, Polypodium leucotomos Poir. is the only one being commercially utilized for this purpose. In this work, we evaluated the concentration of the skin bioactive compounds: quinic and chlorogenic acid, in the extract of 20 wild ferns from Costa Rica. We also evaluated the antimicrobial capabilities of the crude extracts of wild ferns and the sun protection factor (SPF) of the extracts. We found 19 out of 20 have either an important concentration of the compounds mentioned above or antimicrobial properties. Also, most samples result in higher SPF than P. aureum's rhizome. We also have studied the fern acclimatization, at different shading conditions, finding a significant influence of the culturing conditions on metabolite production. After acclimatization. So far, we demonstrate that various ferns included in this study are a potential source of treatments for skin conditions.

Innovative Approaches for Maintaining and Enhancing Skin Health and Managing Skin Diseases through Microbiome-Targeted Strategies

The skin microbiome is crucial in maintaining skin health, and its disruption is associated with various skin diseases. Prebiotics are non-digestible fibers and compounds found in certain foods that promote the activity and growth of beneficial bacteria in the gut or skin. On the other hand, live microorganisms, known as probiotics, benefit in sustaining healthy conditions when consumed in reasonable quantities. They differ from postbiotics, which are by-product compounds from bacteria that release the same effects as their parent bacteria. The human skin microbiome is vital when it comes to maintaining skin health and preventing a variety of dermatological conditions. This review explores novel strategies that use microbiome-targeted treatments to maintain and enhance overall skin health while managing various skin disorders. It is important to understand the dynamic relationship between these beneficial microorganisms and the diverse microbial communities present on the skin to create effective strategies for using probiotics on the skin. This understanding can help optimize formulations and treatment regimens for improved outcomes in skincare, particularly in developing solutions for various skin problems.

The urinary, vaginal and gut microbiota in women with genital lichen sclerosus - A case-control study

BACKGROUND

Lichen sclerosus (LS) is a chronic, autoimmune skin disease predominantly located in the anogenital region in women. In recent years, the role of the human microbiota in the pathogenesis of autoimmune diseases, including LS, has received interest.

OBJECTIVES

The study aimed to evaluate and compare the composition of the urinary, vaginal and gut microbiota in women with LS versus non-affected controls.

STUDY DESIGN

Women diagnosed with LS (n = 16) and matched controls (n = 14) were enrolled in the study. From each participant, midstream urine, upper and lower vaginal swabs, as well as faecal samples, were collected. The microbiota composition was assessed using 16S ribosomal RNA (rRNA) gene sequencing of the V4 hypervariable region.

RESULTS

We observed no LS-specific clustering in either of the four anatomic niches, using either hierarchical cluster analysis or weighted beta diversity metrics. However, for unweighted UniFrac, significant differences in the urinary and lower vaginal microbiota were observed when comparing women with LS to controls. These findings indicate that while the two groups have microbiota dominated by the same bacteria, variations do occur amongst less abundant bacteria. The LEfSe analysis revealed a higher relative abundance of the genus Streptococcus in the urinary and lower vaginal microbiota in women with LS compared to controls. Additionally, a higher relative abundance of phylum Euryarchaeota was observed in the gut microbiota in women with LS compared to controls.

CONCLUSION

In this study, we demonstrated several differences amongst less abundant bacteria in the urinary, lower vaginal and faecal microbiota when comparing women with LS to controls. However, further research is required to assess whether these microbiota differences are causative or merely a result of the underlying LS disease.

Skin Microbiota and the Cosmetic Industry

Skin harbors an important microbial ecosystem - the skin microbiota that is in homeostasis with its host and is beneficial for human health. Cosmetic products have the potential to interfere with this microbial community; therefore their impact should be assessed. The aim of this review is to highlight the importance of skin microbiota in the cosmetic industry. Several studies determined that cosmetic ingredients have the potential to disrupt the skin microbiota equilibrium leading to the development of skin diseases and dysregulation of immune response. These studies led their investigation by using different methodologies and models, concluding that methods must be chosen according to the aim of the study, the skin site to be evaluated, and the target population of the cosmetics. Overall, it is crucial to test the impact of cosmetics in the skin microbiota and to stablish standard procedures, as well as specific criteria that allow to classify a cosmetic product as skin microbiota friendly.

Staphylococcus epidermidis isolates from atopic or healthy skin have opposite effect on skin cells: potential implication of the AHR pathway modulation

Introduction

Staphylococcus epidermidis is a commensal bacterium ubiquitously present on human skin. This species is considered as a key member of the healthy skin microbiota, involved in the defense against pathogens, modulating the immune system, and involved in wound repair. Simultaneously, S. epidermidis is the second cause of nosocomial infections and an overgrowth of S. epidermidis has been described in skin disorders such as atopic dermatitis. Diverse isolates of S. epidermidis co-exist on the skin. Elucidating the genetic and phenotypic specificities of these species in skin health and disease is key to better understand their role in various skin conditions. Additionally, the exact mechanisms by which commensals interact with host cells is partially understood. We hypothesized that S. epidermidis isolates identified from different skin origins could play distinct roles on skin differentiation and that these effects could be mediated by the aryl hydrocarbon receptor (AhR) pathway.

Methods

For this purpose, a library of 12 strains originated from healthy skin (non-hyperseborrheic (NH) and hyperseborrheic (H) skin types) and disease skin (atopic (AD) skin type) was characterized at the genomic and phenotypic levels.

Results and discussion

Here we showed that strains from atopic lesional skin alter the epidermis structure of a 3D reconstructed skin model whereas strains from NH healthy skin do not. All strains from NH healthy skin induced AhR/OVOL1 path and produced high quantities of indole metabolites in co-culture with NHEK; especially indole-3-aldehyde (IAld) and indole-3-lactic acid (ILA); while AD strains did not induce AhR/OVOL1 path but its inhibitor STAT6 and produced the lowest levels of indoles as compared to the other strains. As a consequence, strains from AD skin altered the differentiation markers FLG and DSG1. The results presented here, on a library of 12 strains, showed that S. epidermidis originated from NH healthy skin and atopic skin have opposite effects on the epidermal cohesion and structure and that these differences could be linked to their capacity to produce metabolites, which in turn could activate AHR pathway. Our results on a specific library of strains provide new insights into how S. epidermidis may interact with the skin to promote health or disease.

Melanogenesis and Hypopigmentation: The Case of Vitiligo

Melanocytes are highly specialized dendritic cells that synthesize and store melanin in subcellular organelles called melanosomes, before transfer to keratinocytes. Melanin is a complex pigment that provides colour and photoprotection to the skin, hair and eyes. The process of synthesis of melanin is called melanogenesis and is regulated by various mechanisms and factors such as genetic, environmental and endocrine factors. The knowledge of the pigmentation process is important to understand hypopigmentation disorders such as vitiligo and also to design adequate treatments. In the present work, we review the signalling pathways involved in vitiligo. Finally, current therapies and treatments including topical, oral and phototherapies are discussed and described, emphasizing future therapies based on different pigmentation mechanisms.

Psoriasis: Interplay between dysbiosis and host immune system

With advancement in human microbiome research, an increasing number of scientific evidences have endorsed the key role of both gut and skin microbiota in the pathogenesis of psoriasis. Microbiome dysbiosis, characterized by altered diversity and composition, as well as rise of pathobionts, have been identified as possible triggers for recurrent episodes of psoriasis. Mechanistically, gut dysbiosis leads to "leaky gut syndrome" via disruption of epithelial bilayer, thereby, resulting in translocation of bacteria and other endotoxins to systemic circulation, which in turn, results in inflammatory response. Similarly, skin dysbiosis disrupts the cutaneous homeostasis, leading to invasion of bacteria and other pathogens to deeper layers of skin or even systemic circulation further enhanced by injury caused by pruritus-induced scratching, and elicit innate and adaptive inflammation. The present review explores the correlation of both skin and gut microbiota dysbiosis with psoriasis. Also, the studies highlighting the potential of bacteriotherapeutic approaches including probiotics, prebiotics, metabiotics, and fecal microbiota transplantation for the management of psoriasis have been discussed.

Current Concepts of Vitiligo Immunopathogenesis

Vitiligo is an acquired immune-mediated disorder of pigmentation clinically characterized by well-defined depigmented or chalk-white macules and patches on the skin. The prevalence of vitiligo varies by geographical area, affecting 0.5% to 2% of the population. The disease imposes a significant psychological burden due to its major impact on patients’ social and emotional aspects of life. Given its autoimmune background, vitiligo is frequently associated with other autoimmune diseases or immune-mediated diseases. Vitiligo is a multifaceted disorder that involves both genetic predisposition and environmental triggers. In recent years, major predisposing genetic loci for the development of vitiligo have been discovered. The current findings emphasize the critical role of immune cells and their mediators in the immunopathogenesis of vitiligo. Oxidative-stress-mediated activation of innate immunity cells such as dendritic cells, natural killer, and ILC-1 cells is thought to be a key event in the early onset of vitiligo. Innate immunity cells serve as a bridge to adaptive immunity cells including T helper 1 cells, cytotoxic T cells and resident memory T cells. IFN-γ is the primary cytokine mediator that activates the JAK/STAT pathway, causing keratinocytes to produce the key chemokines CXCL9 and CXCL10. Complex interactions between immune and non-immune cells finally result in apoptosis of melanocytes. This paper summarizes current knowledge on the etiological and genetic factors that contribute to vitiligo, with a focus on immunopathogenesis and the key cellular and cytokine players in the disease’s inflammatory pathways.

Integrated Analysis of lncRNA and circRNA Mediated ceRNA Regulatory Networks in Skin Reveals Innate Immunity Differences Between Wild-Type and Yellow Mutant Rainbow Trout (Oncorhynchus mykiss)

Fish skin is a vital immune organ that forms the first protective barrier preventing entry of external pathogens. Rainbow trout is an important aquaculture fish species that is farmed worldwide. However, our knowledge of innate immunity differences between wild-type (WR_S) and yellow mutant rainbow trout (YR_S) remains limited. In this study, we performed whole transcriptome analysis of skin from WR_S and YR_S cultured in a natural flowing water pond. A total of 2448 mRNAs, 1630 lncRNAs, 22 circRNAs and 50 miRNAs were found to be differentially expressed (DE). Among these DEmRNAs, numerous key immune-related genes, including ifih1, dhx58, trim25, atp6v1e1, tap1, tap2, cd209, hsp90a.1, nlrp3, nlrc3, and several other genes associated with metabolism (gstp1, nampt, naprt and cd38) were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of DEmRNAs revealed that many were significantly enriched in innate immune-related GO terms and pathways, including NAD+ADP-ribosyltransferase activity, complement binding, immune response and response to bacterium GO terms, and RIG-I-like receptor signaling, NOD-like receptor signaling and phagosome KEGG pathways. Furthermore, the immune-related competing endogenous RNA networks were constructed, from which we found that lncRNAs MSTRG.11484.2, MSTRG.32014.1 and MSTRG.29012.1 regulated at least three immune-related genes (ifih1, dhx58 and irf3) through PC-5p-43254_34, PC-3p-28352_70 and bta-miR-11987_L-1R-1_1ss8TA, and tap2 was regulated by two circRNAs (circRNA5279 and circRNA5277) by oni-mir-124a-2-p5_1ss13GA. The findings expand our understanding of the innate immune system of rainbow trout, and lay the foundation for further study of immune mechanisms and disease resistance breeding.

Metabolic Basis and Clinical Evidence for Skin Lightening Effects of Thiol Compounds

Melanin pigment is a major factor in determining the color of the skin, and its abnormal increase or decrease can cause serious pigmentation disorders. The melanin pigment of the skin is divided into light pheomelanin and dark eumelanin, and a big difference between them is whether they contain sulfur. Melanin synthesis starts from a common reaction in which tyrosine or dihydroxyphenylalanine (DOPA) is oxidized by tyrosinase (TYR) to produce dopaquinone (DQ). DQ is spontaneously converted to leukodopachrome and then oxidized to dopachrome, which enters the eumelanin synthesis pathway. When DQ reacts with cysteine, cysteinyl dopa is generated, which is oxidized to cysteinyl DQ and enters the pheomelanin synthesis pathway. Therefore, thiol compounds can influence the relative synthesis of eumelanin and pheomelanin. In addition, thiol compounds can inhibit enzymatic activity by binding to copper ions at the active site of TYR, and act as an antioxidant scavenging reactive oxygen species and free radicals or as a modulator of redox balance, thereby inhibiting overall melanin synthesis. This review will cover the metabolic aspects of thiol compounds, the role of thiol compounds in melanin synthesis, comparison of the antimelanogenic effects of various thiol compounds, and clinical trials on the skin lightening efficacy of thiol compounds. We hope that this review will help identify the advantages and disadvantages of various thiol compounds as modulators of skin pigmentation and contribute to the development of safer and more effective strategies for the treatment of pigmentation disorders.

Gut microbiota and immunity relevance in eubiosis and dysbiosis

Human gut is colonized by numerous microorganisms, in which bacteria present the highest proportion of this colonization that live in a symbiotic relationship with the host. This microbial collection is commonly known as the microbiota. The gut microbiota can mediate gut epithelial and immune cells interaction through vitamins synthesis or metabolic products. The microbiota plays a vital role in growth and development of the main components of human’s adaptive and innate immune system, while the immune system regulates host-microbe symbiosis. On the other hand, negative alteration in gut microbiota composition or gut dysbiosis, can disturb immune responses. This review highlights the gut microbiota-immune system cross-talk in both eubiosis and dysbiosis.

Advances in Microbiome-Derived Solutions and Methodologies Are Founding a New Era in Skin Health and Care

The microbiome, as a community of microorganisms and their structural elements, genomes, metabolites/signal molecules, has been shown to play an important role in human health, with significant beneficial applications for gut health. Skin microbiome has emerged as a new field with high potential to develop disruptive solutions to manage skin health and disease. Despite an incomplete toolbox for skin microbiome analyses, much progress has been made towards functional dissection of microbiomes and host-microbiome interactions. A standardized and robust investigation of the skin microbiome is necessary to provide accurate microbial information and set the base for a successful translation of innovations in the dermo-cosmetic field. This review provides an overview of how the landscape of skin microbiome research has evolved from method development (multi-omics/data-based analytical approaches) to the discovery and development of novel microbiome-derived ingredients. Moreover, it provides a summary of the latest findings on interactions between the microbiomes (gut and skin) and skin health/disease. Solutions derived from these two paths are used to develop novel microbiome-based ingredients or solutions acting on skin homeostasis are proposed. The most promising skin and gut-derived microbiome interventional strategies are presented, along with regulatory, safety, industrial, and technical challenges related to a successful translation of these microbiome-based concepts/technologies in the dermo-cosmetic industry.

Skin Deep: The Role of the Microbiota in Cutaneous Autoimmunity

The skin microbiota is thought to possibly contribute to the pathogenesis of skin autoimmune diseases. The gut microbiota affects systemically the development and function of the immune system, thereby potentially influencing cutaneous autoimmunity as well. In this paper, we review the role of the gut and skin microbiota in cutaneous autoimmune diseases. Besides direct inflammatory effects at the skin barrier, microbiota may contribute to the pathogenesis of skin autoimmune diseases by metabolites, recall immune cell responses, and permeation of antigens to the subepidermal space. Skin and gut barrier dysfunction may represent a common pathophysiologic process allowing microbiota or its particles to promote autoimmune diseases at barrier surfaces.

Anatomically distinct fibroblast subsets determine skin autoimmune patterns

The skin serves as a physical barrier and an immunological interface that protects the body from the external environment1-3. Aberrant activation of immune cells can induce common skin autoimmune diseases such as vitiligo, which are often characterized by bilateral symmetric lesions in certain anatomic regions of the body4-6. Understanding what orchestrates the activities of cutaneous immune cells at an organ level is necessary for the treatment of autoimmune diseases. Here we identify subsets of dermal fibroblasts that are responsible for driving patterned autoimmune activity, by using a robust mouse model of vitiligo that is based on the activation of endogenous auto-reactive CD8+ T cells that target epidermal melanocytes. Using a combination of single-cell analysis of skin samples from patients with vitiligo, cell-type-specific genetic knockouts and engraftment experiments, we find that among multiple interferon-γ (IFNγ)-responsive cell types in vitiligo-affected skin, dermal fibroblasts are uniquely required to recruit and activate CD8+ cytotoxic T cells through secreted chemokines. Anatomically distinct human dermal fibroblasts exhibit intrinsic differences in the expression of chemokines in response to IFNγ. In mouse models of vitiligo, regional IFNγ-resistant fibroblasts determine the autoimmune pattern of depigmentation in the skin. Our study identifies anatomically distinct fibroblasts with permissive or repressive IFNγ responses as the key determinant of body-level patterns of lesions in vitiligo, and highlights mesenchymal subpopulations as therapeutic targets for treating autoimmune diseases.

A Pilot Study: Composition and Diversity of 16S rRNA Based Skin Bacterial Microbiome in Indonesian Atopic Dermatitis Population

Background

Atopic dermatitis (AD) interferes with quality of life and is influenced by important factors like skin microbiome. The results of the skin microbiome composition and diversity in AD varied in some studies.

Purpose

This study aims to determine the composition and diversity of the skin microbiome in Indonesian AD patients.

Patients and Methods

Genomic deoxyribonucleic acid (DNA) preparations were obtained from skin swabs of the cubital fossa of 16 subjects, nine of which were having mild AD, three moderate AD, and four healthy individuals. DNA extraction and sequencing of the 16S ribosomal ribonucleic acid (rRNA) gene using next-generation sequencing and bioinformatics analysis were further performed.

Results

Firmicutes (p), Bacilli (c), Bacillales (o), Staphylococcaceae (f), and Staphylococcus (g) were dominant in moderate AD. On the contrary, Proteobacteria (p), Gammaproteobacteria (c), Pseudomonadales (o), Moraxellaceae (f), and Acinetobacter (g) were dominant in mild AD. Staphylococcus aureus was found in the highest number in individuals with moderate AD. Interestingly, Ensifer adhaerens was found in mild AD. Microbial diversity was decreased in moderate AD.

Conclusion

Metagenomic analysis in this study identified microbes in moderate and mild AD and showed a low diversity of skin microbiomes in moderate AD. Interestingly, this is the first time that the bacteria Ensifer adhaerens was detected on the human skin.

Interplay Between Skin Microbiota Dysbiosis and the Host Immune System in Psoriasis: Potential Pathogenesis

Psoriasis is a multifactorial immune-mediated disease. The highly effective and eligible treatment for psoriasis is limited, for its specific pathogenesis is incompletely elucidated. Skin microbiota is a research hotspot in the pathogenesis of immune-mediated inflammatory skin diseases nowadays, and it may have significant involvement in the provocation or exacerbation of psoriasis with broadly applicable prospects. It is postulated that skin microbiota alternation may interplay with innate immunity such as antimicrobial peptides and Toll-like receptors to stimulate T-cell populations, resulting in immune cascade responses and ultimately psoriasis. Achieving a thorough understanding of its underlying pathogenesis is crucial. Herein, we discuss the potential immunopathogenesis of psoriasis from the aspect of skin microbiota in an attempt to yield insights for novel therapeutic and preventive modalities for psoriasis.

Differences in the skin microbial community between patients with active and stable vitiligo based on 16S rRNA gene sequencing

BACKGROUND/OBJECTIVE

Recent studies have described an association between altered skin microbial community and epidemiology of skin diseases, such as vitiligo, atopic dermatitis and psoriasis. In this study, we conducted microbiological analysis on patients at different stages of vitiligo to determine whether the dysbiosis is associated with disease progression.

METHODS

To characterise the skin microbes in vitiligo patients, we profiled samples collected from 40 patients with active and stable vitiligo using the Novaseq sequencer. Alpha diversity was used to measure richness and uniformity, while Beta diversity (Non-Metric Multi-Dimensional Scaling) analysis was used to show the differences. Moreover, the species differences were evaluated by LEfSe analysis and the flora gene function was predicted using Statistical Analysis of Metagenomic Profiles (STAMP).

RESULTS

The alpha diversity results showed no significant differences between active vitiligo and stable vitiligo, while beta diversity and LEfSe analysis results showed the differences in community composition. Streptomyces and Streptococcus were enriched in active vitiligo compared to stable vitiligo. In addition, the flora gene function of mixed acid fermentation was more pronounced in active vitiligo, while the function of lipid IVA biosynthesis was more significant in stable vitiligo.

CONCLUSION

This study has shown the differences in epidermal microbes between active vitiligo and stable vitiligo. Our results suggest that maintaining the flora balance might be a potential therapeutic target for vitiligo.

Skin microbiota dynamics following B. subtilis formulation challenge: an in vivo study in mice

BACKGROUND

Modulating the microbiota is a leading-edge strategy for the restoration and maintenance of a healthy, balanced environment. The use of health-promoting bacteria has demonstrated some potential benefits as an alternative for skin microbiota intervention. Here, we investigate the manipulation of mice skin microbiota using B. subtilis incorporated into a supportive Pluronic F-127 hydrogel formulation. The formula plays an important role in delivering the bacteria to the desired action site.

RESULTS

The B. subtilis challenge induced a shift in the composition and abundance of the skin microbiota. Containment of B. subtilis in the Pluronic F-127 hydrogel accelerated bacterial modulation compared with free B. subtilis. The abundance of both Staphylococcus and Corynebacterium spp. was altered as a result of the live bacterial intervention: the abundance of Corynebacterium increased while that of Staphylococcus decreased. Four days after last application of the B. subtilis formulation, B. subtilis counts returned to its initial level.

CONCLUSIONS

B. subtilis intervention can induce a shift in the skin microbiota, influencing the abundance of commensal, beneficial, and pathogenic bacteria. Containment of B. subtilis in Pluronic hydrogel accelerates the microbial alteration, probably by facilitating bacterial attachment and supporting continuous growth. Our results reveal the ability of B. subtilis in Pluronic to modulate the skin microbiota composition, suggesting that the formulation holds therapeutic potential for skin disease treatment.

Dendritic cells maintain anti-tumor immunity by positioning CD8 skin-resident memory T cells

Tissue-resident memory (T_RM) T cells are emerging as critical components of the immune response to cancer; yet, requirements for their ongoing function and maintenance remain unclear. APCs promote T_RM cell differentiation and re-activation but have not been implicated in sustaining T_RM cell responses. Here, we identified a novel role for dendritic cells in supporting T_RM to melanoma. We showed that CD8 T_RM cells remain in close proximity to dendritic cells in the skin. Depletion of CD11c⁺ cells results in rapid disaggregation and eventual loss of melanoma-specific T_RM cells. In addition, we determined that T_RM migration and/or persistence requires chemotaxis and adhesion mediated by the CXCR6/CXCL16 axis. The interaction between CXCR6-expressing T_RM cells and CXCL16-expressing APCs was found to be critical for sustaining T_RM cell-mediated tumor protection. These findings substantially expand our knowledge of APC functions in T_RM T-cell homeostasis and longevity.

Emerging role of Tissue Resident Memory T cells in vitiligo: From pathogenesis to therapeutics

Vitiligo is an acquired depigmenting disorder which affects both skin and mucous membranes and autoimmunity has been strongly suggested to play a role in loss of melanocytes. The recurrence of skin macules at the same sites where they were observed prior to the treatment, suggests the existence of Tissue Resident Memory T cells (TRMs) that persist within the skin or peripheral tissues with a longer survivability. Emerging studies have shown that reactivation of these skin TRMs results into autoreactive TRM cells in various autoimmune diseases including vitiligo. This review focuses on different subsets (CD8+ TRMs and CD4+ TRMs) of TRM cells, their retention and survivability in the skin along with their pathomechanisms leading to melanocyte death and progression of vitiligo. In addition, the review describes the TRM cells as potential targets for developing effective therapeutics of vitiligo.

Identification of L-Cysteinamide as a Potent Inhibitor of Tyrosinase-Mediated Dopachrome Formation and Eumelanin Synthesis

The purpose of this study is to identify amino acid derivatives with potent anti-eumelanogenic activity. First, we compared the effects of twenty different amidated amino acids on tyrosinase (TYR)-mediated dopachrome formation in vitro and melanin content in dark-pigmented human melanoma MNT-1 cells. The results showed that only L-cysteinamide inhibited TYR-mediated dopachrome formation in vitro and reduced the melanin content of cells. Next, the antimelanogenic effect of L-cysteinamide was compared to those of other thiol compounds (L-cysteine, N-acetyl L-cysteine, glutathione, L-cysteine ethyl ester, N-acetyl L-cysteinamide, and cysteamine) and positive controls with known antimelanogenic effects (kojic acid and β-arbutin). The results showed the unique properties of L-cysteinamide, which effectively reduces melanin content without causing cytotoxicity. L-Cysteinamide did not affect the mRNA and protein levels of TYR, tyrosinase-related protein 1, and dopachrome tautomerase in MNT-1 cells. L-Cysteinamide exhibited similar properties in normal human epidermal melanocytes (HEMs). Experiments using mushroom TYR suggest that L-cysteinamide at certain concentrations can inhibit eumelanin synthesis through a dual mechanism by inhibiting TYR-catalyzed dopaquinone synthesis and by diverting the synthesized dopaquinone to the formation of DOPA-cysteinamide conjugates rather than dopachrome. Finally, L-cysteinamide was shown to increase pheomelanin content while decreasing eumelanin and total melanin contents in MNT-1 cells. This study suggests that L-cysteinamide has an optimal structure that can effectively and safely inhibit eumelanin synthesis in MNT-1 cells and HEMs, and will be useful in controlling skin hyperpigmentation.

Probiotics in the Therapeutic Arsenal of Dermatologists

During the last years, numerous studies have described the presence of significant gut and skin dysbiosis in some dermatological diseases such as atopic dermatitis, psoriasis and acne, among others. How the skin and the gut microbiome play a role in those skin conditions is something to explore, which will shed light on understanding the origin and implication of the microbiota in their pathophysiology. Several studies provide evidence for the influence of probiotic treatments that target the modulation of the skin and intestinal microbiota in those disorders and a positive influence of orally administered probiotics on the course of these dermatosis. The pathologies in which the therapeutic role of the probiotic has been explored are mainly atopic dermatitis, psoriasis and acne. This article aims to review these three dermatological diseases, their relationship with the human microbiota and specially the effect of probiotics usage. In addition, the pathophysiology in each of them and the hypotheses about possible mechanisms of the action of probiotics will be described.

Arbutin as a Skin Depigmenting Agent with Antimelanogenic and Antioxidant Properties

Arbutin is a compound of hydroquinone and D-glucose, and it has been over 30 years since there have been serious studies on the skin lightening action of this substance. In the meantime, there have been debates and validation studies about the mechanism of action of this substance as well as its skin lightening efficacy and safety. Several analogs or derivatives of arbutin have been developed and studied for their melanin synthesis inhibitory action. Formulations have been developed to improve the stability, transdermal delivery, and release of arbutin, and device usage to promote skin absorption has been developed. Substances that inhibit melanin synthesis synergistically with arbutin have been explored. The skin lightening efficacy of arbutin alone or in combination with other active ingredients has been clinically evaluated. Combined therapy with arbutin and laser could give enhanced depigmenting efficacy. The use of arbutin causes dermatitis rarely, and caution is recommended for the use of arbutin-containing products, especially from the viewpoint that hydroquinone may be generated during product use. Studies on the antioxidant properties of arbutin are emerging, and these antioxidant properties are proposed to contribute to the skin depigmenting action of arbutin. It is hoped that this review will help to understand the pros and cons of arbutin as a cosmetic ingredient, and will lead to future research directions for developing advanced skin lightening and protecting cosmetic products.

Challenges in exploring and manipulating the human skin microbiome

The skin is the exterior interface of the human body with the environment. Despite its harsh physical landscape, the skin is colonized by diverse commensal microbes. In this review, we discuss recent insights into skin microbial populations, including their composition and role in health and disease and their modulation by intrinsic and extrinsic factors, with a focus on the pathobiological basis of skin aging. We also describe the most recent tools for investigating the skin microbiota composition and microbe-skin relationships and perspectives regarding the challenges of skin microbiome manipulation. Video abstract.

Targeting Innate Immunity to Combat Cutaneous Stress: The Vitiligo Perspective

Multiple factors are involved in the process leading to melanocyte loss in vitiligo including environmental triggers, genetic polymorphisms, metabolic alterations, and autoimmunity. This review aims to highlight current knowledge on how danger signals released by stressed epidermal cells in a predisposed patient can trigger the innate immune system and initiate a cascade of events leading to an autoreactive immune response, ultimately contributing to melanocyte disappearance in vitiligo. We will explore the genetic data available, the specific role of damage-associated-molecular patterns, and pattern-recognition receptors, as well as the cellular players involved in the innate immune response. Finally, the relevance of therapeutic strategies targeting this pathway to improve this inflammatory and autoimmune condition is also discussed.

Analysis of Matched Skin and Gut Microbiome of Patients with Vitiligo Reveals Deep Skin Dysbiosis: Link with Mitochondrial and Immune Changes

Vitiligo is an autoimmune disease characterized by patchy, white skin owing to melanocyte loss. Commensal cutaneous or gut dysbiosis has been linked to various dermatological disorders. In this study, we studied the skin and gut microbiota of patients with vitiligo compared with those of healthy controls. We obtained swabs and biopsies from both lesional and nonlesional skin as well as stool and blood samples from each individual. We detected reduced richness and diversity of microbiota in the stools of subjects with vitiligo compared with the stools of the controls (P < 0.01). Skin swabs had greater α-diversity than biopsies (P < 0.001); swabs from lesional sites were primarily depleted of Staphylococcus compared with those from nonlesional sites (P < 0.02). Sampling deeper layers from the same patients showed differences in both α- and β-diversity between samples with decreased richness and distribution of species (P < 0.01) in the lesional site. Biopsy microbiota from the lesional skin had distinct microbiota composition, which was depleted of protective Bifidobacterium and Bacteroides but was enriched in Proteobacteria, Streptococcus, Mycoplasma, and mtDNA (P < 0.001); the latter increased in the same patients with heightened innate immunity and stress markers in their blood (P < 0.05). These data describe vitiligo-specific cutaneous and gut microbiota and a link between skin dysbiosis, mitochondrial damage, and immunity in patients with vitiligo.

Stem Cell Therapy Offers a Possible Safe and Promising Alternative Approach for Treating Vitiligo: A Review

BACKGROUND

Normal skin pigmentation pattern is an extremely important component of the appearance of a person, as it can be a significant factor in the social context of any person. A condition known as vitiligo is caused by the death of melanocytes leading to pigmentation loss in the skin. This affects all races across the globe and sometimes leads to social avoidance as in some communities, it is stigmatized. Although there are different pathobiological processes suspected because of the different underlying causes of vitiligo, autoimmunity and oxidative stress are suspected to be the most probable ones.

OBJECTIVE

In this review, we present an overview of the underlying mechanisms causing and developing the disease. Also, some of the most successful treatments along with the clinical applications of Mesenchymal Stem Cells (MSCs) as a comprehensive approach for treating this condition will be covered.

RESULTS

Autoreactive CD8+ T-cells are the primary suspect considered to be responsible for the destruction of melanocytes. Therefore, topical use of autoimmune inhibitors including those derived from MSCs, thanks to their immune-modulatory properties, have been reported to be successful in the promotion of repigmentation. MSCs can suppress the proliferation of CD8+T via the NKG2D pathway while inducing T-cell apoptosis. The use of pharmacological agents for reducing cellular oxidative stress with the help of topical application of antioxidants and growth factors also have been in use. Intravenous administration of MSCs has been shown to regulate the level of reactive oxidative species (ROS) in a mice model. Growth factors derived from platelet-rich-plasma (PRP) or from MSCs caused rapid tissue regeneration.

CONCLUSIONS

Finally, MSC therapy also has been shown to stimulate the mobilization of healthy melanocytes, leading to successful repigmentation of skin lesions in vitiligo patients.

Structural aspects of lesional and non-lesional skin microbiota reveal key community changes in leprosy patients from India

Although skin is the primary affected organ in Leprosy, the role of the skin microbiome in its pathogenesis is not well understood. Recent reports have shown that skin of leprosy patients (LP) harbours perturbed microbiota which grants inflammation and disease progression. Herein, we present the results of nested Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) which was initially performed for investigating the diversity of bacterial communities from lesional skin (LS) and non-lesional skin (NLS) sites of LP (n = 11). Further, we performed comprehensive analysis of 16S rRNA profiles corresponding to skin samples from participants (n = 90) located in two geographical locations i.e. Hyderabad and Miraj in India. The genus Staphylococcus was observed to be one of the representative bacteria characterizing healthy controls (HC; n = 30), which in contrast was underrepresented in skin microbiota of LP. Taxa affiliated to phyla Firmicutes and Proteobacteria were found to be signatures of HC and LS, respectively. Observed diversity level changes, shifts in core microbiota, and community network structure support the evident dysbiosis in normal skin microbiota due to leprosy. Insights obtained indicate the need for exploring skin microbiota modulation as a potential therapeutic option for leprosy.

New solution of beauty problem by Staphylococcus hominis: Relevance between skin microbiome and skin condition in healthy subject

BACKGROUND/AIMS

Recently, it was suggested that skin microbiome is related to some skin disease. The possibility of affecting the skin might be high, but there were few reports of the influence on the skin condition in healthy subjects. Our aim was to evaluate the relationship between skin condition and skin microbiome in healthy subjects.

METHODS

Experiment 1: 293 Japanese healthy women were divided into two groups, good skin properties and poor skin properties by 14 skin physiology parameter values on the cheek using noninvasive method. Differences of abundance of bacterial species on the cheek between the two groups were evaluated. Experiment 2: 11 Japanese healthy women were applied Staphylococcus hominis (S. hominis) on half-side of cheek for eight times in 1 month. Difference of change of physiology parameter values comparing to placebo side was evaluated.

RESULTS

Experiment 1: Multiple skin bacterial species were found to be significantly relevant in 14 physiology parameters. The abundance of S. hominis on the cheek with good skin properties group was significantly higher than poor skin properties group. Experiment 2: The application of S. hominis improved significantly the conspicuous pore number, melanin index, and the wrinkle count compared to placebo side.

CONCLUSION

We found many skin bacterial species that might improve the skin condition in healthy women. In particular, S. hominis might have the potential to improve multiple skin beauty problems.

Myron Gordon Award paper: Microbes, T-cell diversity and pigmentation

Melanocytes are static, minimally proliferative cells. This leaves them vulnerable in vitiligo. Yet upon malignant transformation, they form vicious tumors. This profound switch in physiology is accompanied by genetic change and is driven by environmental factors. If UV exposure in younger years supports malignant transformation and melanoma formation, it can likewise impart mutations on melanocytes that reduce their viability, to initiate vitiligo. A wide variety of microbes can influence these diametrically opposed outcomes before either disease takes hold. These microbes are vehicles of change that we are only beginning to study. Once a genetic modification occurs, there is a wide variety of immune cells ready to respond. Though it does not act alone, the T cell is among the most decisive responders in this process. The same biochemical process that offered the skin protection by producing melanin can become an Achilles heel for the cell when the T cells target melanosomal enzymes or, on occasion, neoantigens. T cells are precise, determined, and consequential when they strike. Here, we probe the relationship between the microbiome and its metabolites, epithelial integrity, and the activation of T cells that target benign and malignant melanocytes in vitiligo and melanoma.

Changes in microbial community structure due to chronic trace element concentrations in different sizes of soil aggregates

Studies on the effects of trace elements (TEs) (e.g. Cu, Cd, Zn) on soil microbial communities have provided useful information on the toxicity of TEs to microbes. However, previous studies mainly focused on the effects of TEs on microbial community structure in intact soil, while there are few studies on the impact of TEs on microbial community structure in soil aggregates. In this study, soils previously polluted for 20 years, and now containing low and high TE concentrations derived from, now abandoned, metal smelters were sampled from the surface layer (0-15 cm) of two adjacent Chinese paddy fields. The aim was to determine the effects of TEs on the soil microbial biomass and community structure in different sized soil aggregates. Long-term high TE pollution decreased microbial biomass concentration and species, changed the proportion of bacteria and fungi and decreased the diversity of bacteria in the different sized aggregates. The microbial communities in soil aggregates became clustered with increasing TE concentrations.

Alterations in the conjunctival surface bacterial microbiome in bacterial keratitis patients

Microbial keratitis is an infectious disease of the eye, in which the cornea is inflamed. Under severe conditions, keratitis can lead to significant loss of vision and enucleation of the eye. Ocular trauma is the major risk factor causing keratitis and microorganisms viz., bacteria, fungi, viruses are the causative agents. The current study characterized the conjunctival bacterial microbiomes of healthy individuals and individuals with bacterial keratitis (BK) and assessed whether ocular microbiome dysbiosis is prevalent in BK patients. Ocular bacterial microbiomes were generated from the conjunctival swabs of healthy controls (HC-SW) and conjunctival swabs (BK-SW) and corneal scrapings (BK-CR) of BK patients using V3-V4 amplicon sequencing and data analysed using QIIME and R software. The Alpha diversity indices, diversity and abundance of different phyla and genera, heat map analysis, NMDS plots and inferred functional pathway analysis clearly discriminated the bacterial microbiomes of conjunctival swabs of healthy controls from that of BK patients. Preponderance of negative interactions in the hub genera were observed in BK-CR and BK-SW compared to HC-SW. In addition, a consistent increase in the abundance of pathogenic bacteria, as inferred from published literature, was observed in the conjunctiva of BK patients compared to HC and this may be related to causing or exacerbating ocular surface inflammation. This is the first study demonstrating dysbiosis in the ocular bacterial microbiome of conjunctiva of bacterial keratitis patients compared to the eye of healthy controls. The bacterial microbiome associated with the corneal scrapings of keratitis individuals is also described for the first time.

An update on Vitiligo pathogenesis

Vitiligo, the most common depigmenting disorder of the skin, is undergoing a period of intense advances in both disease understanding and therapeutic possibilities leading the way to the beginning of a new era for the disorder. Its pathophysiology has gathered the attention of researchers for years, and many advances have been made in the clarification of the interaction between different factors that result in depigmented macule formation. The complex interplay between non-immunological and immunological factors in vitiligo is key for the development of the disease, and the participation of cells other than melanocytes, such as keratinocytes, fibroblasts, natural killer cells, and innate lymphoid cells, has been shown. Recent advances have also brought to the understanding of the complex part played by a specific subtype of T cells: T-resident memory cells. This review analyzes some of the most recent insights in vitiligo pathogenesis underlining the interactions between different cell types, which are the basis for the therapeutic approaches under development.

Gut Microbial Dysbiosis and Plasma Metabolic Profile in Individuals With Vitiligo

Autoimmune diseases are increasingly linked to aberrant gut microbiome and relevant metabolites. However, the association between vitiligo and the gut microbiome remains to be elucidated. Thus, we conducted a case-control study through 16S rRNA sequencing and serum untargeted-metabolomic profiling based on 30 vitiligo patients and 30 matched healthy controls. In vitiligo patients, the microbial composition was distinct from that of healthy controls according to the analysis on α- and β-diversity (P < 0.05), with a characteristic decreased Bacteroidetes: Firmicutes ratio. Meanwhile, the levels of 23 serum metabolites (including taurochenodeoxycholate and L-NG-monomethyl-arginine) in the vitiligo patients were different from those in the healthy individuals and showed significant correlations with some microbial markers. We found that Corynebacterium 1, Ruminococcus 2, Jeotgalibaca and Psychrobacter were correlated significantly with disease duration and serum IL-1β level in vitiligo patients. And Psychrobacter was identified as the most predictive features for vitiligo by machine learning analysis ("importance" = 0.0236). Finally, combining multi-omics data and joint prediction models with accuracies up to 0.929 were established with dominant contribution of Corynebacterium 1 and Psychrobacter. Our findings replenished the previously unknown relationship between gut dysbiosis and vitiligo circulating metabolome and enrolled the gut-skin axis into the understanding of vitiligo pathogenesis.

The Human Microbiota in Endocrinology: Implications for Pathophysiology, Treatment, and Prognosis in Thyroid Diseases

The human microbiota is an integral component in the maintenance of health and of the immune system. Microbiome-wide association studies have found numerous diseases associated to dysbiosis. Studies are needed to move beyond correlations and begin to address causation. Autoimmune thyroid diseases (ATD) are one of the most common organ-specific autoimmune disorders with an increasing prevalence, higher than 5% worldwide. Most frequent manifestations of ATD are Hashimoto's thyroiditis and Graves' disease. The exact etiology of ATD remains unknown. Until now it is not clear whether bacterial infections can trigger ATD or modulate the efficacy of treatment and prognosis. The aim of our review is to characterize the microbiota and in ATD and to evaluate the impact of dysbiosis on treatment and prognosis. Moreover, variation of gut microbiome has been associated with thyroid cancer and benign nodules. Here we will characterize the microbioma in benign thyroid nodules, and papillary thyroid cancer to evaluate their implications in the pathophysiology and progression.