Edible Plants and Their Influence on the Gut Microbiome and Acne

Exploring Acne Treatments: From Pathophysiological Mechanisms to Emerging Therapies

Acne vulgaris is a common dermatological condition that can present across different ages but predominantly affects adolescents and young adults. Characterized by various lesion types, the pathogenesis of acne is complex, involving genetic, hormonal, microbial, and inflammatory factors. This review comprehensively addresses current and emerging acne management strategies, emphasizing both topical and systemic treatments, procedural therapies, and dietary modifications. Key topical agents include retinoids, benzoyl peroxide, antibiotics, and other specialized compounds. Systemic options like antibiotics, hormonal therapies, and retinoids offer significant therapeutic benefits, particularly for moderate to severe cases. Procedural treatments such as laser devices, photodynamic therapy, chemical peels, and intralesional injections present viable alternatives for reducing acne symptoms and scarring. Emerging therapies focus on novel biologics, bacteriophages, probiotics, and peptides, providing promising future options. This review underscores the importance of personalized approaches to treatment due to the multifaceted nature of acne, highlighting the potential of innovative therapies for improving patient outcomes.

The Impact of Consuming Probiotics and Following a Vegetarian Diet on the Outcomes of Acne

Acne vulgaris is a common skin condition that affects millions of people worldwide. While the exact cause of acne is not fully understood, it is believed to be influenced by various factors such as the skin microbiome, host immunity, hormones, genetics, and possibly diet. There are several treatment options for acne, including antibiotics and vitamin A derivatives (retinoids). However, these treatments can have side effects, such as dryness, redness, and peeling of the skin. The relationship between diet and acne remains somewhat controversial. Studies have found that Western societies have a higher incidence of acne than non-Western societies, which is believed to be due to dietary differences. Several experiments were conducted to target the skin microbiome and treat acne with the hope of using probiotics orally or topically to regulate the immune response and reduce inflammation in acne. In addition, studies have shown that a plant-based diet can benefit individuals with acne. Avoiding dairy consumption is one of the most effective dietary changes for reducing acne. As part of our investigation, we conducted a review to determine the effect of probiotics and vegetarian diets on acne.

Identification of biomarkers of acne based on transcriptome analysis and combined with network pharmacology to explore the therapeutic mechanism of Jinhuang ointment

The incidence of acne is on the rise due to unhealthy diet and living habits. Jinhuang ointment (JHO) is a classic prescription composed of 10 kinds of commonly used Chinese herbal medicine, which has been widely used in clinical prevention and treatment of skin inflammatory diseases since ancient times. However, the pharmacological mechanism and target of JHO are not clear. The acne microarray dataset was downloaded from gene expression omnibus database to identify differentially expressed genes (DEG). Immune infiltration was analyzed by CiberSort algorithm. HUB gene was identified by protein-protein interaction network. The gene expression omnibus dataset validates the biomarkers of acne with high diagnostic value. The potential active components and targets of JHO were obtained through Traditional Chinese Medicine Systems Pharmacology database, and the therapeutic targets were obtained by crossing with disease targets. R-packet is used for enrichment analysis. Molecular docking using Auto Dock Tools. A total of 202 DEGs were identified from 12 skin samples in the GSE6475. Immune infiltration analysis showed that there were a large number of macrophages and mast cells in acne skin. Gene set enrichment analysis analysis showed that DEGS was mainly involved in bacterial reaction, inflammatory reaction and so on. Six central genes and gene cluster modules were identified by Cytoscape software. A total of 185 JHO active components and 220 targets were obtained, of which 10 targets were potential targets for JHO in the treatment of acne. Kyoto encyclopedia of genes and genomes enrichment analysis showed that JHO treatment of acne was mainly related to Toll-like receptors, IL-17 and other signal pathways. The results of molecular docking showed that 5 active compounds in JHO had strong binding activity to the core protein receptor. IL-1 β, CXCL8, toll-like receptor 2, CXCL2, LCN2, and secretory phosphoprotein 1 may be potential biomarkers for early diagnosis of acne. JHO active components may regulate skin cell metabolism and inflammatory response and improve cellular immune microenvironment by acting on core targets (CXCL8, ESR1, IL-1 β, MMP1, MMP3, secretory phosphoprotein 1), thus achieving the purpose of treating acne. This is the result of the joint action of multiple targets and multiple pathways. It provides an idea for the development of a new combination of drugs for the treatment of acne.

Randomized Double-Blind Placebo-Controlled Supplementation with Standardized Terminalia chebula Fruit Extracts Reduces Facial Sebum Excretion, Erythema, and Wrinkle Severity

Terminalia chebula (TC) is a medicinal plant that exhibits antioxidant, anti-inflammatory, and antibacterial properties and that is widely used in Ayurveda and herbal formulations. However, the skin effects of TC as an oral supplement have not been studied. The objective of this study is to determine if oral TC fruit extract supplementation can modulate the skin's sebum production and reduce the appearance of wrinkles. A prospective double-blind placebo-controlled study was conducted on healthy females aged 25-65. Subjects were supplemented with an oral placebo or Terminalia chebula (250 mg capsule, Synastol TC) capsules twice daily for eight weeks. A facial image collection and analysis system was used to assess the facial appearance of wrinkle severity. Standardized, non-invasive tools were used to measure facial moisture, sebum production, transepidermal water loss, melanin index and erythema index. For those who had a baseline sebum excretion rate >80 ug/cm², TC supplementation produced a significant decrease in forehead sebum excretion rate compared to the placebo at four weeks (-17 decrease vs. 20% increase, p = 0.07) and at eight weeks (-33% decrease vs. 29% increase, p < 0.01). Cheek erythema decreased by 2.2% at eight weeks, while the placebo treatment increased cheek erythema by 1.5% (p < 0.05). Facial wrinkles decreased by 4.3% in the TC group and increased by 3.9% in the placebo group after eight weeks of supplementation (p < 0.05). TC supplementation reduces facial sebum and improves the appearance of wrinkles. Future studies should consider evaluating oral TC as adjuvant therapy for acne vulgaris.

The effect of the ketogenic diet on Acne: Could it be a therapeutic tool?

Acne is a chronic inflammatory disease of the pilosebaceous unit resulting from androgen-induced increased sebum production, altered keratinization, inflammation, and bacterial colonization of the hair follicles of the face, neck, chest and back by Propionibacterium acnes. Overall, inflammation and immune responses are strongly implicated in the pathogenesis of acne. Although early colonization with Propionibacterium acnes and family history may play an important role in the disease, it remains unclear exactly what triggers acne and how treatment affects disease progression. The influence of diet on acne disease is a growing research topic, yet few studies have examined the effects of diet on the development and clinical severity of acne disease, and the results have often been contradictory. Interestingly, very low-calorie ketogenic diet (VLCKD) has been associated with both significant reductions in body weight and inflammatory status through the production of ketone bodies and thus it has been expected to reduce the exacerbation of clinical manifestations or even block the trigger of acne disease. Given the paucity of studies regarding the implementation of VLCKD in the management of acne, this review aims to provide evidence from the available scientific literature to support the speculative use of VLCKD in the treatment of acne.

The Impact of Common Acne on the Well-Being of Young People Aged 15-35 Years and the Influence of Nutrition Knowledge and Diet on Acne Development

Acne is a disorder of sebaceous glands, and it most commonly develops on the face. The role of the diet in triggering and treating acne is controversial and has been widely debated in the literature. A knowledge of the environmental factors that contribute to acne could improve the patient’s physical and emotional well-being, increase the efficacy of treatment, and minimize the risk of anxiety and depressive disorders. The aim of this study was to assess the impact of acne on the daily lives and well-being of people aged 15−30 years, to analyze young people’s knowledge about the influence of various foods and other dietary factors on the prevalence, severity, and treatment of acne, as well as their adherence to an anti-acne diet. The study was conducted between April 2021 and May 2022. A total of 1329 respondents, including 963 women and 366 men, participated in the study. In 99% of men and women respondents, acne breakouts were typically located on the face. An analysis of HADS scores revealed moderate anxiety in 57% of women (F) and 22.5% of men (M) respondents. Acne breakouts located on the face were problematic for 81% of the study population (regardless of sex). More than ¾ of women and 2/3 of men claimed that acne made them feel less attractive. The impact of acne on the participants’ emotional well-being and social life differed between genders. Women experienced psychological discomfort more frequently than men (p = 0.0023). More than 50% of the participants eliminated acne-triggering foods from their diets, and 2/3 of these respondents observed a marked improvement or disappearance of skin breakouts as a result. A significantly higher number of respondents with severe/moderate anxiety were convinced that acne breakouts were affected by diet (OR 1.56; 95% CI 1.23−1.87, p < 0.001) and foods with a high glycemic index (OR 1.56; 95% CI 1.23−1.94, p < 0.001). Acne affects the patients’ emotional well-being. It can act as a barrier to social interactions and lead to mood disorders of varied severity. Persons with moderate/severe mood disorders associated with anxiety significantly more often recognized the role of dietary factors in acne aggravation, and the severity of mood disorders was directly correlated with more frequent consumption of sweets, sweetened beverages, and foods with a high glycemic index.

Advances in the human skin microbiota and its roles in cutaneous diseases

Skin is the largest organ in the human body, and the interplay between the environment factors and human skin leads to some skin diseases, such as acne, psoriasis, and atopic dermatitis. As the first line of human immune defense, skin plays significant roles in human health via preventing the invasion of pathogens that is heavily influenced by the skin microbiota. Despite being a challenging niche for microbes, human skin is colonized by diverse commensal microorganisms that shape the skin environment. The skin microbiota can affect human health, and its imbalance and dysbiosis contribute to the skin diseases. This review focuses on the advances in our understanding of skin microbiota and its interaction with human skin. Moreover, the potential roles of microbiota in skin health and diseases are described, and some key species are highlighted. The prevention, diagnosis and treatment strategies for microbe-related skin diseases, such as healthy diets, lifestyles, probiotics and prebiotics, are discussed. Strategies for modulation of skin microbiota using synthetic biology are discussed as an interesting venue for optimization of the skin-microbiota interactions. In summary, this review provides insights into human skin microbiota recovery, the interactions between human skin microbiota and diseases, and the strategies for engineering/rebuilding human skin microbiota.

Potential roles of gut microbial tryptophan metabolites in the complex pathogenesis of acne vulgaris

Acne vulgaris is a chronic inflammatory skin disease in which the influence of gut microbiota has been implicated but without clarification of mechanisms. Gut microbiota may exert such an influence via metabolites, particularly those of tryptophan. End metabolites of tryptophan activate receptors, including aryl hydrocarbon, G protein-coupled, and pregnane X receptors to stabilize the immune microenvironment and intestinal mucosal homeostasis. Any impact on the pathogenesis of acne vulgaris remains unclear. The current review collates recent advances concerning potential roles of tryptophan metabolism in mediating skin inflammation, follicular sebaceous gland function and intestinal permeability, all of which influence the pathogenesis of acne vulgaris. The aim was to improve understanding of the pathogenesis of acne vulgaris and to expose therapeutic opportunities.

Acne Treatment Review and Future Perspectives

Acne affects approximately 9% of people worldwide and is the most common skin condition in the United States. There are abundant topical and oral treatment options available for patients with acne. First-line agents include topical retinoids, azelaic acid, benzoyl peroxide, and combinations of these agents. For recalcitrant or more severe acne, oral medications, including oral antibiotics, isotretinoin, or hormonal therapy, may be considered. This review will also discuss the many advances being made in the treatment of acne vulgaris, from the development of microencapsulated medications to targeted treatments. This article is protected by copyright. All rights reserved.

The increasing importance of the gut microbiome in acne vulgaris

Acne is a frequently presented dermatological condition brought about by an interplay among inflammation, increased sebum production, hyperkeratinisation, and predominantly Propionibacterium acnes (renamed as Cutibacterium acnes) proliferation, leading to debilitating psychological scars. However, it has been shown that it is the loss of microbial diversity in the skin and the imbalance among C. acnes phylotypes that brings about acne rather than the C. acnes species as a whole. Interestingly, recent evidence suggests that other microorganisms may be implicated, such as the fungi Malassezia and the bacteria Cutibacterium granulosum. A plethora of scientific evidence suggests that the gut microbiome is implicated in the overall health and physiology of the host; studies show that the gut microbiome of acne patients is distinct and depicts less microbial diversity compared to individuals without acne. Herein, using the key terms: acne, C. acnes, IGF-1, sebum, and gut microbiome, we carried out a review of the literature, using Google Scholar and PubMed, and discussed the role of the gut and skin microbiome in relation to acne, as a narrative review. The role of hormones, diet, sebum, and stress in relation to the gut microbiome was also investigated. Therapeutic implications and the use of pre-/postbiotics are also deliberated upon. In this light, future research should investigate the relationship between the gut microbiome and the agreed upon factors of acne pathology, potentially leading to the discovery of novel acne treatments with milder side effects.

Non-conventional therapeutical approaches to acne vulgaris related to its association with metabolic disorders

The ever-increasing frequency of metabolic syndrome (MetS) is still a major challenge of the public health care system, worldwide. In recent years, researchers have been drawn to the uncommon (at first look) link between skin illnesses and MetS. Because of the pro-inflammatory mechanisms and insulin resistance (IR) that are upregulated in metabolic syndrome, many skin disorders are correlated to metabolic dysfunctions, including acne vulgaris. A comprehensive understanding of the link between MetS and acne vulgaris may contribute to the development of new treatment strategies. The current review focuses on dietary and therapeutic interventions and assesses the effect of various approaches such as improving diet by avoiding certain food products (i.e., milk and chocolate) or increasing the intake of others (i.e., food products rich in omega-3 fatty acids), metformin administration, therapy with plant extracts, plant essential oils, and probiotic supplementation on the improvement of certain acne vulgaris severity parameters. These therapeutic approaches, when combined with allopathic treatment, can improve the patients' quality of life.

Facial Acne: A Randomized, Double-Blind, Placebo-Controlled Study on the Clinical Efficacy of a Symbiotic Dietary Supplement

Introduction

Treatments other than topical and systemic antibiotics are needed to restore the dysbiosis correlated with acne onset and evolution. In this view, probiotics and botanical extracts could represent a valid adjunctive therapeutic approach. The purpose of this study was to test the efficacy of a dietary supplement containing probiotics (Bifidobacterium breve BR03 DSM 16604, Lacticaseibacillus casei LC03 DSM 27537, and Ligilactobacillus salivarius LS03 DSM 22776) and botanical extract (lupeol from Solanum melongena L. and Echinacea extract) in subjects with mild to moderate acne over an 8-week study period.

Methods

Monocentric, randomized, double-blind, four-arm, placebo-controlled clinical study involving 114 subjects.

Results

A significant (p < 0.05) effect on the number of superficial inflammatory lesions was reported over the study period in the subjects taking the study agent (group II) (−56.67%), the botanical extracts (group III) (−40.00%), and the probiotics (group IV) (−38.89%) versus placebo (−10.00%). A significant (p < 0.05) decrease in mean desquamation score, sebum secretion rate, and porphyrin mean count versus baseline was also reported, and the effect was most evident for group II. The analysis of log relative abundance after 4 and 8 weeks of treatment compared with baseline showed a significant (p < 0.01) decrease in Cutibacterium acnes and S. aureus, along with a contextually and significant (p < 0.05) increase in Staphylococcus epidermidis, especially in group II. No significant changes were reported for group I.

Conclusion

The results from this study suggest that the administration of the dietary supplement under study was effective, safe, and well tolerated in subjects with mild to moderate acne and could represent a promising optional complement for the treatment of inflammatory acne as well as for control of acne-prone skin.

A Novel Biocompatible Herbal Extract-Loaded Hydrogel for Acne Treatment and Repair

A novel herbal extract-loaded gel containing several biofunctional extracts, including green tea, Zingiber officinale Rosc, Phyllanthus emblica, and salicylic acid, was developed for acne vulgaris. These natural raw materials were blended with suitable dosages of gelatin and carboxymethyl cellulose (CMC) to produce a biocompatible herbal gel. The physical chemistry properties of the hydrogel were determined by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), rheometry, and scanning electron microscopy (SEM), and the hydrogel showed good mechanical and morphological characteristics. The herbal extract-loaded hydrogel mimicked extracellular matrix properties and showed good antioxidant and anti-inflammatory properties and various advantages, serving as a potential wound dressing material because of its high moisture retention ability, wound exudate absorption behavior, and biocompatibility. It exhibited moderate-high antioxidative and anti-inflammatory qualities that were important for dermis wound closure. The clinical trial results showed that most patients experienced moderate to high healing rates, and four of twenty-four individuals (16.67%) had recovery area ratios greater than 80%. This herbal extract-loaded hydrogel has effective ingredients and excellent mechanical properties as a bioactive dressing agent for acne treatment.

Characterization of Weissella viridescens UCO-SMC3 as a Potential Probiotic for the Skin: Its Beneficial Role in the Pathogenesis of Acne Vulgaris

Previously, we isolated lactic acid bacteria from the slime of the garden snail Helix aspersa Müller and selected Weissella viridescens UCO-SMC3 because of its ability to inhibit in vitro the growth of the skin-associated pathogen Cutibacterium acnes. The present study aimed to characterize the antimicrobial and immunomodulatory properties of W. viridescens UCO-SMC3 and to demonstrate its beneficial effect in the treatment of acne vulgaris. Our in vitro studies showed that the UCO-SMC3 strain resists adverse gastrointestinal conditions, inhibits the growth of clinical isolates of C. acnes, and reduces the adhesion of the pathogen to keratinocytes. Furthermore, in vivo studies in a mice model of C. acnes infection demonstrated that W. viridescens UCO-SMC3 beneficially modulates the immune response against the skin pathogen. Both the oral and topical administration of the UCO-SCM3 strain was capable of reducing the replication of C. acnes in skin lesions and beneficially modulating the inflammatory response. Of note, orally administered W. viridescens UCO-SMC3 induced more remarkable changes in the immune response to C. acnes than the topical treatment. However, the topical administration of W. viridescens UCO-SMC3 was more efficient than the oral treatment to reduce pathogen bacterial loads in the skin, and effects probably related to its ability to inhibit and antagonize the adhesion of C. acnes. Furthermore, a pilot study in acne volunteers demonstrated the capacity of a facial cream containing the UCO-SMC3 strain to reduce acne lesions. The results presented here encourage further mechanistic and clinical investigations to characterize W. viridescens UCO-SMC3 as a probiotic for acne vulgaris treatment.

Endocrine Disrupting Chemicals, Hormone Receptors, and Acne Vulgaris: A Connecting Hypothesis

The relationship between endocrine disrupting chemicals (EDCs) and the pathogenesis of acne vulgaris has yet to be explored in the literature. Acne vulgaris is a chronic inflammatory skin disease of the pilosebaceous unit. The pathogenesis of acne involves several hormonal pathways, including androgens, insulin-like growth factor 1(IGF-1), estrogens, and corticosteroids. EDCs influence these pathways primarily through two mechanisms: altering endogenous hormone levels and interfering with hormone receptor function. This review article describes the mechanistic links between EDCs and the development of acne lesions. Highlighted is the contributory role of androgen receptor ligands, such as bisphenol A (BPA) and mono-2-ethylhexyl Phthalate (MEHP), via upregulation of lipogenic genes and resultant exacerbation of cholesterol synthesis. Additionally discussed is the protective role of phytoestrogen EDCs in counteracting androgen-induced sebocyte maturation through attenuation of PPARy transcriptional activity (i.e., resveratrol) and restoration of estrogen-regulated TGF-B expression in skin cells (i.e., genistein). Examination of the relationship between EDCs and acne vulgaris may inform adjunctive avenues of treatment such as limiting environmental exposures, and increasing low-glycemic, plant-rich foods in the diet. With a better understanding of the cumulative role that EDCs play in acne, clinicians can be better equipped to treat and ultimately improve the lives of their patients.

Effect of oral administration of Triphala, a polyphenol-rich prebiotic, on scalp sebum in patients with scalp seborrhea a randomized clinical trial

BACKGROUND

Although there are various therapeutic options to control oily skin, they have potential side effects and limitations especially in long-term use. Pre/probiotics may have beneficial effects in atopic dermatitis' acne, dandruff, and seborrhea, demonstrated by some clinical trials. This trial conducted to determine whether the herbal prebiotic Triphala is effective in reducing scalp sebum secretion in patients with scalp seborrhea.

METHODS

In this 8 week patient and outcome assessor-blinded, placebo-controlled trial participants with scalp seborrhea aged 14-50 years were randomized to Triphala or placebo groups. 1 g of Triphala (standardized as 91.82 ± 0.5 mg gallic acid) or placebo (wheat flour) were administered BID. Scalp sebum levels were detected objectively using Sebumeter^® sm 815, and treatment satisfaction was measured using a score between 0 and 100. [Registration no. IRCT2014070218332N1].

RESULTS

Eighty patients completed the study (40 in Triphala group and 40 in placebo group). Participants in the Triphala group experienced 25.34 scores (95% CI, 0.39-50.29: p = .047) more improvement in scalp sebum levels compared with the placebo group. The mean percentage of patients' satisfaction was 37.91 (24.88) in the Triphala group and 17.89 (25.80) in the placebo group (p = .001).

CONCLUSION

Herbal prebiotic Triphala significantly reduced scalp sebum scores compared to placebo.

The Skin Microbiome: A New Actor in Inflammatory Acne

Our understanding of the role of Cutibacterium acnes in the pathophysiology of acne has recently undergone a paradigm shift: rather than C. acnes hyperproliferation, it is the loss of balance between the different C. acnes phylotypes, together with a dysbiosis of the skin microbiome, which results in acne development. The loss of diversity of C. acnes phylotypes acts as a trigger for innate immune system activation, leading to cutaneous inflammation. A predominance of C. acnes phylotype IA₁ has been observed, with a more virulent profile in acne than in normal skin. Other bacteria, mainly Staphylococcus epidermis, are also implicated in acne. S. epidermidis and C. acnes interact and are critical for the regulation of skin homeostasis. Recent studies also showed that the gut microbiome is involved in acne, through interactions with the skin microbiome. As commonly used topical and systemic antibiotics induce cutaneous dysbiosis, our new understanding of acne pathophysiology has prompted a change in direction for acne treatment. In the future, the development of individualized acne therapies will allow targeting of the pathogenic strains, leaving the commensal strains intact. Such alternative treatments, involving modifications of the microbiome, will form the next generation of ‘ecobiological’ anti-inflammatory treatments.

CMAUP: a database of collective molecular activities of useful plants

The beneficial effects of functionally useful plants (e.g. medicinal and food plants) arise from the multi-target activities of multiple ingredients of these plants. The knowledge of the collective molecular activities of these plants facilitates mechanistic studies and expanded applications. A number of databases provide information about the effects and targets of various plants and ingredients. More comprehensive information is needed for broader classes of plants and for the landscapes of individual plant’s multiple targets, collective activities and regulated biological pathways, processes and diseases. We therefore developed a new database, Collective Molecular Activities of Useful Plants (CMAUP), to provide the collective landscapes of multiple targets (ChEMBL target classes) and activity levels (in 2D target-ingredient heatmap), and regulated gene ontologies (GO categories), biological pathways (KEGG categories) and diseases (ICD blocks) for 5645 plants (2567 medicinal, 170 food, 1567 edible, 3 agricultural and 119 garden plants) collected from or traditionally used in 153 countries and regions. These landscapes were derived from 47 645 plant ingredients active against 646 targets in 234 KEGG pathways associated with 2473 gene ontologies and 656 diseases. CMAUP (http://bidd2.nus.edu.sg/CMAUP/) is freely accessible and searchable by keywords, plant usage classes, species families, targets, KEGG pathways, gene ontologies, diseases (ICD code) and geographical locations.

Potential Role of the Microbiome in Acne: A Comprehensive Review

Acne is a highly prevalent inflammatory skin condition involving sebaceous sties. Although it clearly develops from an interplay of multiple factors, the exact cause of acne remains elusive. It is increasingly believed that the interaction between skin microbes and host immunity plays an important role in this disease, with perturbed microbial composition and activity found in acne patients. Cutibacterium acnes (C. acnes; formerly called Propionibacterium acnes) is commonly found in sebum-rich areas and its over-proliferation has long been thought to contribute to the disease. However, information provided by advanced metagenomic sequencing has indicated that the cutaneous microbiota in acne patients and acne-free individuals differ at the virulent-specific lineage level. Acne also has close connections with the gastrointestinal tract, and many argue that the gut microbiota could be involved in the pathogenic process of acne. The emotions of stress (e.g., depression and anxiety), for instance, have been hypothesized to aggravate acne by altering the gut microbiota and increasing intestinal permeability, potentially contributing to skin inflammation. Over the years, an expanding body of research has highlighted the presence of a gut–brain–skin axis that connects gut microbes, oral probiotics, and diet, currently an area of intense scrutiny, to acne severity. This review concentrates on the skin and gut microbes in acne, the role that the gut–brain–skin axis plays in the immunobiology of acne, and newly emerging microbiome-based therapies that can be applied to treat acne.

Human Microbiome: Composition and Role in Inflammatory Skin Diseases

This review focuses on recent evidences about human microbiome composition and functions, exploring the potential implication of its impairment in some diffuse and invalidating inflammatory skin diseases, such as atopic dermatitis, psoriasis, hidradenitis suppurativa and acne. We analysed current scientific literature, focusing on the current evidences about gut and skin microbiome composition and the complex dialogue between microbes and the host. Finally, we examined the consequences of this dialogue for health and skin diseases. This review highlights how human microbes interact with different anatomic niches modifying the state of immune activation, skin barrier status, microbe-host and microbe-microbe interactions. It also shows as most of the factors affecting gut and skin microorganisms' activity have demonstrated to be effective also in modulating chronic inflammatory skin diseases. More and more evidences demonstrate that human microbiome plays a key role in human health and diseases. It is to be expected that these new insights will translate into diagnostic, therapeutic and preventive measures in the context of personalized/precision medicine.

The influence of exposome on acne

BACKGROUND

Acne vulgaris is one of the main reasons for dermatological consultations. Severity and response to treatment may be impacted by various external factors or exposome.

AIM

To assess the impact of environmental factors on acne and to provide a comprehensive overview of the acne exposome.

METHODS

Two consensus meetings of five European dermatologists and a comprehensive literature search on exposome factors triggering acne served as a basis for this review.

RESULTS

Acne exposome was defined as the sum of all environmental factors influencing the occurrence, duration and severity of acne. Exposome factors impact on the response and the frequency of relapse to treatments by interacting with the skin barrier, sebaceous gland, innate immunity and cutaneous microbiota. They may be classified into the following six main categories: nutrition, psychological and lifestyle factors, occupational factors including cosmetics, as well as pollutants, medication and climatic factors. Moreover, practical considerations for the dermatologist's clinical practice are proposed.

CONCLUSION

Exposome factors including nutrition, medication, occupational factors, pollutants, climatic factors, and psychosocial and lifestyle factors may impact on the course and severity of acne and on treatment efficacy. Identifying and reducing the impact of exposome is important for an adequate acne disease management.

Numerical analyses of intestinal microbiota by data mining

The human intestinal microbiota has a close relationship with health control and causes of diseases, and a vast number of scientific papers on this topic have been published recently. Some progress has been made in identifying the causes or species of related microbiota, and successful results of data mining are reviewed here. Humans who are targets of a disease have their own individual characteristics, including various types of noise because of their individual life style and history. The quantitatively dominant bacterial species are not always deeply connected with a target disease. Instead of conventional simple comparisons of the statistical record, here the Gini-coefficient (i.e., evaluation of the uniformity of a group) was applied to minimize the effects of various types of noise in the data. A series of results were reviewed comparatively for normal daily life, disease and technical aspects of data mining. Some representative cases (i.e., heavy smokers, Crohn’s disease, coronary artery disease and prediction accuracy of diagnosis) are discussed in detail. In conclusion, data mining is useful for general diagnostic applications with reasonable cost and reproducibility.

Diversity of bacterial communities on the facial skin of different age-group Thai males

Background

Skin microbiome varies from person to person due to a combination of various factors, including age, biogeography, sex, cosmetics and genetics. Many skin disorders appear to be related to the resident microflora, yet databases of facial skin microbiome of many biogeographies, including Thai, are limited.

Methods

Metagenomics derived B-RISA and 16S rRNA gene sequencing was utilized to identify the culture-independent bacterial diversity on Thai male faces (cheek and forehead areas). Skin samples were categorized (grouped) into (i) normal (teenage.hea) and (ii) acne-prone (teenage.acn) young adults, and normal (iii) middle-aged (middle.hea) and (iv) elderly (elderly.hea) adults.

Results

The 16S rRNA gene sequencing was successful as the sequencing depth had an estimated >98% genus coverage of the true community. The major diversity was found between the young and elderly adults in both cheek and forehead areas, followed by that between normal and acne young adults. Detection of representative characteristics indicated that bacteria from the order Rhizobiales, genera Sphingomonas and Pseudoalteromonas, distinguished the elderly.hea microbiota, along the clinical features of wrinkles and pores. Prediction of the metabolic potential revealed reduced metabolic pathways involved in replication and repair, nucleotide metabolism and genetic translation in the elderly.hea compared with that in the teenage.hea. For young adults, some unique compositions such as abundance of Propionibacterium acnes and Staphylococcus epidermidis, with a minor diversity between normal and acne skins, were detected. The metabolic potentials of the acne vs. normal young adults showed that teenage.acn was low in many cellular processes (e.g., cell motility and environmental adaptation), but high in carbohydrate metabolism, which could support acne growth. Moreover, comparison with the age-matched males from the US (Boulder, Colorado) to gain insight into the diversity across national biogeography, revealed differences in the distribution pattern of species, although common bacteria were present in both biogeographical samples. Furthermore, B-RISA served as a crosscheck result to the 16S rRNA gene sequencing (i.e., differences between teenage and elderly microbiota).

Conclusions

This study revealed and compared the microbial diversity on different aged Thai male faces, and included analyses for representing the bacterial flora, the clinical skin characteristics, and comparison with the US age-matched. The results represent the first skin microbiota of Thai males, and helps the design of a large-scale skin microbiome study of Thais. The findings of the diversity among ages, skin type and national biogeography supported the importance of these traits in the skin microbiome and in developing a safe and sustainable treatment for acne and aging skin diseases.