Gut microbial composition in patients with psoriasis

Multiomic Analysis of the Gut Microbiome in Psoriasis Reveals Distinct Host‒Microbe Associations

Psoriasis is a chronic, inflammatory skin disease that affects 2‒3% of the global population. Besides skin manifestations, patients with psoriasis have increased susceptibility to a number of comorbidities, including psoriatic arthritis, cardiovascular disease, and inflammatory bowel disease. To understand the systemic component of psoriasis pathogenesis, we performed a pilot study to examine the fecal metagenome, host colonic transcriptome, and host peripheral blood immune profiles of patients with psoriasis and healthy controls. Our study showed increased functional diversity in the gut microbiome of patients with psoriasis. In addition, we identified microbial species that preferentially associate with patients with psoriasis and which have been previously found to associate with other autoimmune diseases. Intriguingly, our data revealed three psoriasis subgroups that have distinct microbial and host features. Integrating these features revealed host‒microbe associations that are specific to psoriasis or particular psoriasis subgroups. Our findings provide insight into the factors that may affect the development of comorbidities in patients with psoriasis and may hold diagnostic potential for early identification of patients with psoriasis at risk for these comorbidities.

Gut–Skin Axis: Unravelling the Connection between the Gut Microbiome and Psoriasis

Evidence has shown that gut microbiome plays a role in modulating the development of diseases beyond the gastrointestinal tract, including skin disorders such as psoriasis. The gut–skin axis refers to the bidirectional relationship between the gut microbiome and skin health. This is regulated through several mechanisms such as inflammatory mediators and the immune system. Dysregulation of microbiota has been seen in numerous inflammatory skin conditions such as atopic dermatitis, rosacea, and psoriasis. Understanding how gut microbiome are involved in regulating skin health may lead to development of novel therapies for these skin disorders through microbiome modulation, in particularly psoriasis. In this review, we will compare the microbiota between psoriasis patients and healthy control, explain the concept of gut–skin axis and the effects of gut dysbiosis on skin physiology. We will also review the current evidence on modulating gut microbiome using probiotics in psoriasis.

Gut Microbiota Dysbiosis and Altered Bile Acid Catabolism Lead to Metabolic Disorder in Psoriasis Mice

Patients with psoriasis tend to have significant comorbidities, such as hyperlipemia, diabetes mellitus, and obesity, which belong to metabolic disorders. The specific mechanism through which psoriasis increases the metabolic disorder risk is uncertain. In this study, we demonstrated that the dysbiotic gut microbiota of 6-month-old psoriasis-like model mice (K14-VEGF-A-transgenic) exacerbated psoriasis disease and induced metabolic disorder when transferred into 2-month-old mice. By 16S rRNA gene sequencing, we confirmed that the Parabacteroides distasonis decreased with age in K14-VEGF mice, and P. distasonis also decreased in the transferred mice. Metabolomic screening identified an altered bile acid profile, including a decrease in chenodeoxycholic acid (CDCA) in the feces of transferred mice. Additionally, CDCA supplements prevented metabolic disorders in K14-VEGF-A-transgenic mice. Consequently, we found that aberrant bile acid metabolism may contribute to metabolic disorder in K14-VEGF-A-transgenic mice, indicating the possibility to prevent and treat the metabolic disorder in psoriasis mice by targeting gut microbial metabolites.

Gut dysbiosis in cutaneous T-cell lymphoma is characterized by shifts in relative abundances of specific bacterial taxa and decreased diversity in more advanced disease

BACKGROUND

Cutaneous T-cell lymphoma (CTCL) patients often suffer from recurrent skin infections and profound immune dysregulation in advanced disease. The gut microbiome has been recognized to influence cancers and cutaneous conditions; however, it has not yet been studied in CTCL.

OBJECTIVES

To investigate the gut microbiome in patients with CTCL and in healthy controls.

METHODS

Case-control study conducted between January 2019 and November 2020 at Northwestern's busy multidisciplinary CTCL clinic (Chicago, Illinois, USA) utilizing 16S ribosomal RNA gene amplicon sequencing and bioinformatics analyses to characterize the microbiota present in fecal samples of CTCL patients (n=38) and age-matched healthy controls (n=13) from the same geographical region.

RESULTS

Gut microbial α-diversity trended lower in patients with CTCL and was significantly lower in patients with advanced CTCL relative to controls (p=0.015). No differences in β-diversity were identified. Specific taxa were significantly reduced in patient samples; significance was determined using adjusted p-values (q-values) that accounted for a false discovery rate threshold of 0.05. Significantly reduced taxa in patient samples included the phylum Actinobacteria (q=0.0002), classes Coriobacteriia (q=0.002) and Actinobacteria (q=0.03), order Coriobacteriales (q=0.003), and genus Anaerotruncus (q=0.01). The families of Eggerthellaceae (q=0.0007) and Lactobacillaceae (q=0.02) were significantly reduced in patients with high skin disease burden.

CONCLUSIONS

Gut dysbiosis can be seen in patients with CTCL compared to healthy controls and is pronounced in more advanced CTCL. The taxonomic shifts associated with CTCL are similar to those previously reported in atopic dermatitis and opposite those of psoriasis, suggesting microbial parallels to the immune profile and skin barrier differences between these conditions. These findings may suggest new microbial disease biomarkers and reveal a new angle for intervention.

Patients with psoriasis have a dysbiotic taxonomic and functional gut microbiota

BACKGROUND

Accumulating evidence supports the findings of an altered gut microbiota in patients with autoimmune disease, however existing literature on the role of the gut microbiota in patients with psoriasis have demonstrated conflicting results and have mainly been based on 16s rRNA gene sequencing analysis OBJECTIVES: To examine whether the gut microbiota of patients with psoriasis was altered in composition and functional potentials compared with healthy controls and as a second approach compared with healthy cohabitant partners; further, to investigate relationships to disease severity and seasonal impact on the gut microbiota.

METHODS

In a case-control study, 126 faecal samples were collected from a sample of 53 systemically untreated patients with plaque psoriasis; 52 age, sex, and BMI matched healthy controls; and 21 cohabitant partners. A subpopulation of 18 patients with psoriasis and 19 healthy controls continued in a longitudinal study, where 4-6 faecal samples were collected over 9-12 months. The gut microbiota was characterized using shotgun metagenomic sequencing analysis.

RESULTS

A significantly lower richness (p=0.007) and difference in community composition (p=0.01) of metagenomic species (MGS) was seen in patients with psoriasis compared with healthy controls, and patients with psoriasis had a lower microbial diversity than their partners (p=0.04). Additionally, the functional richness was decreased in patients with psoriasis compared with healthy controls (p=0.01) and partners (p=0.05). Increased disease severity was correlated with alterations in taxonomy and function, with a slight tendency towards a lower richness of MGS, albeit not significant (p=0.08). The seasonal analysis showed no shifts in community composition in healthy controls or in patients with psoriasis.

CONCLUSIONS

The findings of a different gut microbiota in composition and functional potentials between patients with psoriasis and healthy controls support a linkage between the gut microbiota and psoriasis. These findings need to be validated in larger studies and a potential causal relation between the gut microbiota and psoriasis still needs to be shown.

The role of gut microbiome in inflammatory skin disorders: A systematic review

The close relationship between the intestine and the skin has been widely stated, seen from gastrointestinal (GI) disorders often accompanied by skin manifestations. Exactly how the gut microbiome is related to skin inflammation and influences the pathophysiology mechanism of skin disorders are still unclear. Many studies have shown a two-way relationship between gut and skin associated with GI health and skin homeostasis and allostasis. This systematic review aimed to explore the associations between the gut microbiome with inflammatory skin disorders, such as acne, psoriasis, atopic dermatitis, and urticaria, and to discover the advanced concept of this relationship. The literature search was limited to any articles published up to December 2020 using PubMed and EBSCOHost. The review followed the PRISMA guidelines for conducting a systematic review. Of the 319 articles screened based on title and abstract, 111 articles underwent full-text screening. Of these, 23 articles met our inclusion criteria, comprising 13 atopic dermatitis (AD), three psoriasis, four acne vulgaris, and four chronic urticaria articles. Acne vulgaris, atopic dermatitis, psoriasis, and chronic urticaria are inflammation skin disorders that were studied recently to ascertain the relationship of these disorders with dysbiosis of the GI microbiome. All acne vulgaris, psoriasis, and chronic urticaria studies stated the association of gut microbiome with skin manifestations. However, the results in atopic dermatitis are still conflicting. Most of the articles agree that Bifidobacterium plays an essential role as anti-inflammation bacteria, and Proteobacteria and Enterobacteria impact inflammation in inflammatory skin disorders.

The Role of the Gut Microbiome in Psoriasis: From Pathogens to Pathology

OBJECTIVE

The objective of this article is to bring awareness to the emerging frontier of the correlation of the gut microbiome and its impact on psoriasis.

METHODS

A Google Scholar and PubMed literature search was conducted utilizing key words "gut microbiome," "psoriasis," "diet," and "inflammation," yielding several articles for review and classification.

RESULTS

Randomized, controlled trials have revealed that gut microbial imbalances contribute to inflammatory cytokines as well as to the progression and development of psoriasis. Perhaps more importantly, perturbations in the gut microbiome have been correlated to elevated plasma levels of claudin-3, zonulin, and intestinal fatty acid-binding protein, contributing to intestinal barrier dysfunction and permeability. This translocation results in systemic immune activation leading to phenotypic expression of psoriasis in genetically susceptible individuals.

LIMITATIONS

Numerous limitations were found during the research on this topic, including lack of standardization of diets, coverage of stool testing by insurance, and personalized interactions of microbes on the host. Further studies are needed with longer follow-up and increased number of patients.

CONCLUSION

A healthy diet positively impacts the gut microbiome, which can dampen inflammatory cytokines and lessen the severity of psoriasis. The use of probiotics can also influence this dynamic.

The Gut Microbiome in Psoriasis and Crohn’s Disease: Is Its Perturbation a Common Denominator for Their Pathogenesis?

Psoriasis and inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD), are interlinked. In fact, the prevalence of IBD is higher in patients with psoriasis, with a risk of ulcerative colitis of 1.6-times higher than in the general population. Analogously, patients with psoriasis have a greater risk of developing IBD. Furthermore, they share some clinical features and pathogenic mechanisms. Both are chronic inflammatory diseases with a relapsing-remitting condition that persists for the patient’s whole life and exhibit increased permeability of the mucosal barrier of skin and gut, allowing an increased interaction of pathogens with inflammatory receptors of the immune cells. A key element in the pathogenesis of these diseases is represented by the microbiota; in particular, the gut microbiota is an important driver of CD pathogenesis, while in psoriasis changes in gut and skin microbiota have been described without a defined pathogenic function. Furthermore, genetic predispositions or environmental factors contribute to disease manifestation, with a central role attributed to the immune responses and, in particular, to a dysregulated role played by T helper 17 cells both in psoriasis and IBD. The purpose of this review was to summarize present information about the links between psoriasis, inflammatory bowel disease, in particular Crohn’s disease, and changes in gut and/or skin microbiome.

Investigation of intestinal microbiome in chronic spontaneous urticaria patients

BACKGROUND

Chronic urticaria is a disorder characterized by itchy erythematous plaques with edema lasting 6 weeks or more. The prevalence is 1%, and two thirds of these cases are "chronic spontaneous urticaria (CSU)." Drugs, food, infections, and systemic diseases may be etiologic factors for CSU, although it may be idiopathic.

OBJECTIVES

The aim of this study was to compare the diversity and distribution of the intestinal microbiome in CSU patients with that of healthy individuals. The hypothesis was to determine the probable association of intestinal microbiome with CSU.

METHODS

This study was conducted in Sakarya University Training and Research Hospital, Department of Dermatology. In this study, 20 CSU patients and 10 healthy volunteers were included. Stool samples were collected from all participants. 16S RNA sequencing and bioinformatic analysis were performed after isolation of DNA isolation from all samples.

RESULTS

Diversity in microorganisms, stool pH averages, Bristol scores, and the ratio of Firmicutes/Bacteroidetes were the significant changes between the two groups.

LIMITATIONS

Due to high cost involved in microbiota studies, only a limited number of patients and volunteers participated.

CONCLUSION

The alteration in the intestinal microbiota (dysbiosis) may be an essential factor for CSU development and may explain idiopathic cases.

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.

Yaobitong capsules reshape and rebalance the gut microbiota and metabolites of arthritic rats: An integrated study of microbiome and fecal metabolomics analysis

Yaobitong capsule (YBTC), a Chinese medicine compound preparation, has been demonstrated to affect multiple pathways associated with inflammation and exhibit potential anti-arthritis effect. In this study, an integrated omic approach based on UHPLC-Q-TOF MS and 16S rRNA sequencing analyses was proposed to reveal the anti-arthritis effect and possible mechanism of YBTC. The AIA rat model showed that YBTC significantly alleviated the typical symptoms of AIA rats such as weight, spleen index and pro-inflammatory cytokines. Fecal metabolomics results identified 41 differential metabolites, which mainly referred to tryptophan, bile acid and fatty acid metabolism. The gut microbiota played a crucially important role in anti-inflammatory immunity, 16S rRNA results indicated that YBTC changed the community structure and alleviated the microecological imbalance caused by rheumatoid arthritis (RA). Further ROC curve analysis demonstrated that it was reliable to identify RA by using 5 metabolites and 3 microorganisms (AUC > 0.83). In summary, it was the first time that the preventive effect of YBTC in RA was confirmed. The secretion of the microbiota-mediated metabolites was significantly improved by YBTC, through its callback effect on the disturbed gut microbiota. Thus, we have indicated a potential novel strategy for the prevention of RA via evaluation of intervention effects of YBTC on AIA rat model.

Nutritional Therapy in Persons Suffering from Psoriasis

Psoriasis is a chronic inflammatory skin disease. Immunological, genetic, and environmental factors, including diet, play a part in the pathogenesis of psoriasis. Metabolic syndrome or its components are frequent co-morbidities in persons with psoriasis. A change of eating habits can improve the quality of life of patients by relieving skin lesions and by reducing the risk of other diseases. A low-energy diet is recommended for patients with excess body weight. Persons suffering from psoriasis should limit the intake of saturated fatty acids and replace them with polyunsaturated fatty acids from the omega-3 family, which have an anti-inflammatory effect. In diet therapy for persons with psoriasis, the introduction of antioxidants such as vitamin A, vitamin C, vitamin E, carotenoids, flavonoids, and selenium is extremely important. Vitamin D supplementation is also recommended. Some authors suggest that alternative diets have a positive effect on the course of psoriasis. These diets include: a gluten-free diet, a vegetarian diet, and a Mediterranean diet. Diet therapy for patients with psoriasis should also be tailored to pharmacological treatment. For instance, folic acid supplementation is introduced in persons taking methotrexate. The purpose of this paper is to discuss in detail the nutritional recommendations for persons with psoriasis.

The gut microbiota profile in psoriasis: a Brazilian case-control study

The pathogenesis of psoriasis, an immune-mediated chronic inflammatory skin disease, remains unclear. Studies have shown an association between psoriasis and intestinal inflammation; in this context, the influence of the gut microbiota on the immune response of psoriasis has become a focus of recent research. The present research evaluated the composition and diversity of the gut microbiota of 21 participants with psoriasis from a Brazilian referral dermatology service compared to 24 healthy controls. A stool sample was collected from each participant at the time of inclusion in the study, and the samples were analysed by sequencing the 16S rRNA gene. The recruitment of research participants involved matching between groups by sex, age, body mass index, comorbidities and smoking and the exclusion of several criteria that could potentially influence the gut microbiota and the interpretation of the data. There was an increase in the Dialister genus and Prevotella copri species in patients with psoriasis compared to the control group. A reduction in the Ruminococcus, Lachnospira and Blautia genera, as well as in the Akkermansia muciniphila species, was also verified in the psoriasis group compared to the control group. Furthermore, patients with psoriasis exhibited less gut microbiota diversity than controls.

Involvement of Gut Microbiota in the Development of Psoriasis Vulgaris

Objectives: Psoriasis is a common chronic recurrent dermatitis. Accumulating observations show gut microbiota dysbiosis in psoriasis. We intend to further investigate the relationship between intestinal microbiota and psoriasis development.

Design: We first performed an epidemiological investigation on differences of gastrointestinal discomfort symptoms between patients with psoriasis and general population. Then variation of gut microbiota in patients with psoriasis (un)treated with acitretin plus narrow-band ultraviolet B (NB-UVB) was analyzed by 16S rRNA sequencing. We last compared recovery status and vital cytokines (lesion and intestine) of mouse psoriasiform models, which were transplanted with fecal microbiota from patients with psoriasis or healthy controls.

Results: (1) About 85.5% of patients with psoriasis vs. 58.1% of healthy controls presented with at least one gastrointestinal symptom. The prevalence of investigated symptoms (e.g., abdominal distension and constipation) were significantly higher in patients, compared with controls (p < 0.05). Passing flatus and constipation were significantly correlated with psoriasis (p < 0.05 in both cases). (2) The abundance of Ruminococcaceae family, Coprococcus_1 genus, and Blautia genus were decreased with psoriasis improvement (p < 0.05, respectively), which had been demonstrated significantly increased in psoriasis. (3) Mice receiving psoriatic microbes transplantation showed delayed recovery of psoriasiform dermatitis and less reduction of interleukin (IL)-17A than those receiving healthy microbiota or blank control (p < 0.05 and p < 0.01, respectively).

Conclusion: Multiple evidence we provided here preliminarily demonstrates the involvement of gut microbiota in the different degree of psoriasis activity. The strategy based on overall microbial communities is expected to be a promising supplementary for long-term management of psoriasis.

Next- and Third-Generation Sequencing Outperforms Culture-Based Methods in the Diagnosis of Ascitic Fluid Bacterial Infections of ICU Patients

OBJECTIVES

Infections of the ascitic fluid are serious conditions that require rapid diagnosis and treatment. Ascites is often accompanied by other critical pathologies such as gastrointestinal bleeding and bowel perforation, and infection increases the risk of mortality in intensive care patients. Owing to a relatively low success rate of conventional culture methods in identifying the responsible pathogens, new methods may be helpful to guide antimicrobial therapy and to refine empirical regimens. Here, we aim to assess outcomes and to identify responsible pathogens in ascitic fluid infections, in order to improve patients' care and to guide empirical therapy.

METHODS

Between October 2019 and March 2021, we prospectively collected 50 ascitic fluid samples from ICU patients with suspected infection. Beside standard culture-based microbiology methods, excess fluid underwent DNA isolation and was analyzed by next- and third-generation sequencing (NGS) methods.

RESULTS

NGS-based methods had higher sensitivity in detecting additional pathogenic bacteria such as E. faecalis and Klebsiella in 33 out of 50 (66%) ascitic fluid samples compared with culture-based methods (26%). Anaerobic bacteria were especially identified by sequencing-based methods in 28 samples (56%), in comparison with only three samples in culture. Analysis of clinical data showed a correlation between sequencing results and various clinical parameters such as peritonitis and hospitalization outcomes.

CONCLUSIONS

Our results show that, in ascitic fluid infections, NGS-based methods have a higher sensitivity for the identification of clinically relevant pathogens than standard microbiological culture diagnostics, especially in detecting hard-to-culture anaerobic bacteria. Patients with such infections may benefit from the use of NGS methods by the possibility of earlier and better targeted antimicrobial therapy, which has the potential to lower the high morbidity and mortality in critically ill patients with ascitic bacterial infection.

The skin microbiome and the gut-skin axis

The microbiome plays a significant role in human health, homeostasis, immune system, and disease pathogenesis. Disrupted communication between the microbiome and host has been extensively studied in gastrointestinal diseases. To a lesser extent, there is emerging research on the skin microbiome and its connection with the gut, referred to as the gut-skin axis and its effects on dermatologic conditions. A basic overview will be provided of the gut and skin microbiome with a focus on the impact of this connection on cutaneous diseases, such as psoriasis, atopic dermatitis, rosacea, acne vulgaris, photoaging, and cutaneous wounds. In addition, we shall discuss nutrition-based approaches mediated through the gut-skin axis and topical treatments that could serve as potential adjunctive management by manipulation of the microbiome. In particular, there is a growing body of research on oral probiotics, prebiotics, and dietary modifications that may help improve symptoms for a variety of dermatologic conditions in select demographic groups.

Both the microbiome and the macrobiome can influence immune responsiveness in psoriasis

It is debatable whether intestinal dysbiosis in autoimmune disease is a cause or a consequence of chronic inflammation, but it is known that intestinal dysbiosis in the course of the disease is accompanied by an increased number of pro-inflammatory lymphocytes in the Th17 population. Yet, little is known about the systemic implications of skin and even the intestinal microbiome for skin immunity and pathogenesis in psoriasis, which the most prevalent autoimmune disease in the Caucasian population. The pathogenesis of psoriasis is multifactorial with notable contributions from genetics and environmental factors (e.g. diet, drugs and infection). This article describes alterations in the microbiome and macrobiome, which are involved in immune regulation. The composition of the gut microbiome can dramatically affect immune development and affect susceptibility to diseases, especially autoimmune disorders such as psoriasis. Understanding the mechanisms of pathogenesis induced by the micro- and macrobiome may prove crucial for innovative future solutions in skin disease treatment.

Relevance of organ(s)-on-a-chip systems to the investigation of food-gut microbiota-host interactions

The ever greater understanding of the composition and function of the gut microbiome has provided new opportunities with respect to understanding and treating human disease. However, the models employed for in vitro and in vivo animal studies do not always provide the required insights. As a result, one such alternative in vitro cell culture based system, organ-on-a-chip technology, has recently attracted attention as a means of obtaining data that is representative of responses in humans. Organ-on-a-chip systems are designed to mimic the interactions of different tissue elements that were missing from traditional two-dimensional tissue culture. While they do not traditionally include a microbiota component, organ-on-a-chip systems provide a potentially valuable means of characterising the interactions between the microbiome and human tissues with a view to providing even greater accuracy. From a dietary perspective, these microbiota-organ-on-a-chip combinations can help researchers to predict how the consumption of specific foods and ingredients can impact on human health and disease. We provide an overview of the relevance and interactions of the gut microbiota and the diet in human health, we summarise the components involved in the organ-on-a-chip systems, how these systems have been employed for microbiota based studies and their potential relevance to study the interplay between food-gut microbiota-host interactions.

New Frontiers in Psoriatic Disease Research, Part I: Genetics, Environmental Triggers, Immunology, Pathophysiology, and Precision Medicine

Psoriasis is a chronic inflammatory condition characterized by systemic immune dysregulation. Over the past several years, advances in genetics, microbiology, immunology, and mouse models have revealed the complex interplay between the heritable and microenvironmental factors that drive the development of psoriatic inflammation. In the first of this two-part review series, the authors will discuss the newest insights into the pathogenesis of psoriatic disease and highlight how the evolution of these scientific fields has paved the way for a more personalized approach to psoriatic disease treatment.

Metagenomic analysis revealed the potential role of gut microbiome in gout

Emerging evidence indicates an association between gut microbiome and arthritis diseases including gout. However, how and which gut bacteria affect host urate degradation and inflammation in gout remains unclear. Here we performed a metagenome analysis on 307 fecal samples from 102 gout patients and 86 healthy controls. Gout metagenomes significantly differed from those of healthy controls. The relative abundances of Prevotella, Fusobacterium, and Bacteroides were increased in gout, whereas those of Enterobacteriaceae and butyrate-producing species were decreased. Functionally, gout patients had greater abundances for genes in fructose, mannose metabolism and lipid A biosynthesis, and lower for genes in urate degradation and short chain fatty acid production. A three-pronged association between metagenomic species, functions and clinical parameters revealed that decreased abundances of species in Enterobacteriaceae were associated with reduced amino acid metabolism and environmental sensing, which together contribute to increased serum uric acid and C-reactive protein levels in gout. A random forest classifier based on three gut microbial genes showed high predictivity for gout in both discovery and validation cohorts (0.91 and 0.80 accuracy), with high specificity in the context of other chronic disorders. Longitudinal analysis showed that uric-acid-lowering and anti-inflammatory drugs partially restored gut microbiota after 24-week treatment. Comparative analysis with obesity, type 2 diabetes, ankylosing spondylitis and rheumatoid arthritis indicated that gout metagenomes were more similar to those of autoimmune than metabolic diseases. Our results suggest that gut dysbiosis was associated with dysregulated host urate degradation and systemic inflammation and may be used as non-invasive diagnostic markers for gout.

Inflammatory bowel disease and psoriasis: modernizing the multidisciplinary approach

Psoriasis and inflammatory bowel disease (IBD) are immune-mediated diseases occurring in barrier organs whose main task is to protect the organism from attack. These disorders are highly prevalent especially in northern Europe where psoriasis has a prevalence of around 3-4% and IBD around 0.3%. The prevalence of IBD in North America has been estimated at around 0.4%. The total incidence rates in northern Europe have been estimated at around 6 for Crohn's disease and 11 for ulcerative colitis per 100 000 person-years, compared with an incidence rate of around 280 per 100 000 person-years for psoriasis. Both diseases are less common in countries with a lower index of development. The rise in IBD appears to occur as populations adopt a westernized lifestyle, whereas psoriasis seems more stable and prevalence differences may derive more from variation in genetic susceptibility. The gut microbiota is clearly an important driver of IBD pathogenesis; in psoriasis, changes in gut and skin microbiota have been reported, but it is less clear whether and how these changes contribute to the pathogenesis. Large studies show that most identified genes are involved in the immune system. However, psoriasis and IBD are highly heterogeneous diseases and there is a need for more precise and deeper phenotyping to identify specific subgroups and their genetic, epigenetic and molecular signatures. Epigenetic modifications of DNA such as histone modifications, noncoding RNA effects on transcription and translation and DNA methylation are increasingly recognized as the mechanism underpinning much of the gene-environment interaction in the pathogenesis of both IBD and psoriasis. Our understanding of underlying pathogenetic mechanisms has deepened fundamentally over the past decades developing hand in hand with novel therapies targeting pathways and proinflammatory cytokines incriminated in disease. There is not only substantial overlap between psoriasis and IBD, but also there are differences with implication for therapy. In psoriasis, drugs targeting interleukin-23 and interleukin-17 have shown superior efficacy compared with anti-TNFs, whilst in IBD, drugs targeting interleukin-17 may be less beneficial. The therapeutic toolbox for psoriasis is impressive and is enlarging also for IBD. Still, there are unmet needs reflecting the heterogeneity of both diseases and there is a need for closer molecular diagnostics to allow for the development of precise therapeutics.

Metabolic Syndrome and Psoriasis: Mechanisms and Future Directions

Psoriasis is an immune-mediated systemic disease with associated comorbidities, including metabolic syndrome (MetS) which contributes substantially to premature mortality in patients with psoriasis. However, the pathological mechanisms underlying this comorbidity are unclear. Studies have shown that the pathological parameters of psoriasis mediate the development of MetS. We reviewed the potential mechanisms which mediate the association between psoriasis and MetS, including endoplasmic reticulum stress, pro-inflammatory cytokine releases, excess production of reactive oxygen species, alterations in adipocytokine levels and gut microbiota dysbiosis. Here, we highlight important research questions regarding this association and offer insights into MetS research and treatment.

Thrombosis in Psoriasis: Cutaneous Cytokine Production as a Potential Driving Force of Haemostatic Dysregulation and Subsequent Cardiovascular Risk

Psoriasis (PsO) is a common T cell-mediated inflammatory disorder of the skin with an estimated prevalence of 2%. The condition manifests most commonly as erythematous plaques covered with scales. The aetiology of PsO is multifactorial and disease initiation involves interactions between environmental factors, susceptibility genes, and innate and adaptive immune responses. The underlying pathology is mainly driven by interleukin-17. In addition, various inflammatory mediators from specific T helper (T_H) cell subsets, namely T_H1, T_H17, and T_H22, are overexpressed in cutaneous lesions and may also be detected in the peripheral blood of psoriatic patients. Moreover, these individuals are also at greater risk, compared to the general population, of developing multiple comorbid conditions. Cardiovascular disease (CVD) has been recognised as a prominent comorbidity of PsO. A potential mechanism contributing to this association may be the presence of a hypercoagulable state in these individuals. Inflammation and coagulation are closely related. The presence of chronic, low-grade systemic inflammation may promote thrombosis – one of the major determinants of CVD. A pro-inflammatory milieu may induce the expression of tissue factor, augment platelet activity, and perturb the vascular endothelium. Altogether, these changes will result in a prothrombotic state. In this review, we describe the aetiology of PsO, as well as the pathophysiology of the condition. We also consider its relationship to CVD. Given the systemic inflammatory nature of PsO, we evaluate the potential contribution of prominent inflammatory mediators (implicated in PsO pathogenesis) to establishing a prothrombotic state in psoriatic patients.

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.

Potential Role of Probiotics in Ameliorating Psoriasis by Modulating Gut Microbiota in Imiquimod-Induced Psoriasis-Like Mice

Psoriasis is an immune-mediated systemic disease that may be treated with probiotics. In this study, probiotic strains that could or could not decrease interleukin (IL)-17 levels were applied to imiquimod (IMQ)-induced psoriasis-like mice via oral administration. Bifidobacterium adolescentis CCFM667, B. breve CCFM1078, Lacticaseibacillus paracasei CCFM1074, and Limosilactobacillus reuteri CCFM1132 ameliorated psoriasis-like pathological characteristics and suppressed the release of IL-23/T helper cell 17 (Th17) axis-related inflammatory cytokines, whereas B. animalis CCFM1148, L. paracasei CCFM1147, and L. reuteri CCFM1040 neither alleviated the pathological characteristics nor reduced the levels of inflammatory cytokines. All effective strains increased the contents of short-chain fatty acids, which were negatively correlated with the levels of inflammatory cytokines. By performing 16S rRNA gene sequencing, the diversity of gut microbiota in psoriasis-like mice was found to decrease, but all effective strains made some specific changes to the composition of gut microbiota compared to the ineffective strains. Furthermore, except for B. breve CCFM1078, all other effective strains decreased the abundance of the family Rikenellaceae, which was positively correlated with psoriasis-like pathological characteristics and was negatively correlated with propionate levels. These findings demonstrated effects of strain-specificity, and how probiotics ameliorated psoriasis and provide new possibilities for the treatment of psoriasis.

Microbiome of the Healthy External Auditory Canal

OBJECTIVE

To investigate the microbiota of the healthy external auditory canal (EAC) culture-independently and to evaluate the usefulness of the swabbing method in collecting EAC microbiota samples.

STUDY DESIGN

Cohort study.

PATIENTS

Fifty healthy asymptomatic working-age volunteers.

INTERVENTION

Samples were harvested with DNA-free swabs from the volunteers' EACs.

MAIN OUTCOME MEASURES

Amplicon sequencing of the 16S rRNA gene was used to characterize the microbial communities in the samples.

RESULTS

The swabbing method is feasible for EAC microbiota sample collection. The analyzed 41 samples came from 27 female and 14 male subjects; 4 samples were excluded due to recent antimicrobial treatment and 5 because of low sequence count or suspected contaminant microbes. The four most frequent amplicon sequence variants in the microbiota data were Staphylococcus auricularis, Propionibacterium acnes, Alloiococcus otitis, and Turicella otitidis. Typically, the dominant amplicon sequence variant in a sample was one of the most frequent bacteria, but there were also subjects where the dominant species was not among the most frequent ones. The genus Alloiococcus was least common in females who reported cleaning their ears. Subjects with a high relative abundance of Alloiococcus typically had a low abundance of Staphylococcus, which may be a sign of the two being competing members of the microbial community.

CONCLUSIONS

The most common bacteria in the microbiome of the healthy EAC were Staphylococcus auricularis, Propionibacterium acnes, Alloiococcus otitis, and Turicella otitidis. The EAC microbiota seems more diverse and individualized than previously thought. Also, ear cleaning habits seem to alter the EAC microbiome.

Gut Microbiome Alterations and Functional Prediction in Chronic Spontaneous Urticaria Patients

The effects of the gut microbiome on both allergy and autoimmunity in dermatological diseases have been indicated in several recent studies. Chronic spontaneous urticaria (CSU) is a disease involving allergy and autoimmunity, and there is no report detailing the role of microbiota alterations in its development. This study was performed to identify the fecal microbial composition of CSU patients and investigate the different compositions and potential genetic functions on the fecal microbiota between CSU patients and normal controls. The gut microbiota of CSU patients and healthy individuals were obtained by 16s rRNA massive sequencing. Gut microbiota diversity and composition were compared, and bioinformatics analysis of the differences was performed. The gut microbiota composition results showed that Firmicutes, Bacteroidetes, Proteobacteria, and Verrucomicrobia were dominant microbiota in CSU patients. The differential analysis showed that relative abundance of the Proteobacteria (p = 0.03), Bacilli (p = 0.04), Enterobacterales (p = 0.03), Enterobacteriaceae (p = 0.03) was significantly increased in CSU patients. In contrast, the relative abundance of Megamonas, Megasphaera, and Dialister (all p < 0.05) in these patients significantly decreased compared with healthy controls. The different microbiological compositions impacted normal gastrointestinal functions based on function prediction, resulting in abnormal pathways, including transport and metabolism. We found CSU patients exhibited gut microbiota dysbiosis compared with healthy controls. Our results indicated CSU is associated with gut microbiota dysbiosis and pointed out that the bacterial taxa increased in CSU patients, which might be involved in the pathogenesis of CSU. These results provided clues for future microbial-based therapies on CSU.

Abnormal composition of microbiota in the gut and skin of imiquimod-treated mice

Psoriasis is a chronic, inflammatory skin disease. Although the precise etiology of psoriasis remains unclear, gut-microbiota axis might play a role in the pathogenesis of the disease. Here we investigated whether the composition of microbiota in the intestine and skin is altered in the imiquimod (IMQ)-treated mouse model of psoriasis. Topical application of IMQ to back skin caused significant changes in the composition of microbiota in the intestine and skin of IMQ-treated mice compared to control mice. The LEfSe algorithm identified the species Staphylococcus lentus as potential skin microbial marker for IMQ group. Furthermore, there were correlations for several microbes between the intestine and skin, suggesting a role of skin-gut-microbiota in IMQ-treated mice. Levels of succinic acid and lactic acid in feces from IMQ-treated mice were significantly higher than control mice. Moreover, the predictive functional analysis of the microbiota in the intestine and skin showed that IMQ caused alterations in several KEGG pathways. In conclusion, the current data indicated that topical application with IMQ to skin alters the composition of the microbiota in the gut and skin of host. It is likely that skin-gut microbiota axis plays a role in pathogenesis of psoriasis.

Comparison of Behavioral Risk Factors and Cardiometabolic Comorbidities of Psoriatic Arthritis and Psoriasis: A Case-Control Study in Chinese Patients

Purpose

Comparison of risk factors and comorbidities could help indicate the underlying mechanisms of diseases. This study aimed to compare behavioral factors and cardiometabolic comorbidities of PsA/psoriasis versus healthy controls to implicate the similarities and differences in potential pathogenic mechanisms for further research.

Patients and Methods

A case-control study in Chinese patients with PsA or psoriasis and healthy controls was conducted. Clinical information based on patient-reported and measured outcomes were collected. Multivariable logistic regression was used to investigate the associations, in terms of adjusted odds ratios (AORs).

Results

We randomly selected 171 patients with PsA, 342 with psoriasis, and 1026 healthy controls from our database, matching by age and sex. Dyslipidemia (AOR=4.62 for PsA and 2.97 for psoriasis) and alcohol drinking (AOR=3.20 for PsA and 3.62 for psoriasis) were significantly associated with both diseases. Overweight was inversely associated with both PsA (AOR=0.46, P=0.002) and psoriasis (AOR=0.56, P=0.001), while obesity was associated with PsA (AOR=2.02, P=0.025) but not psoriasis (AOR=0.87, P=0.621). Subgroup analysis by onset age of psoriatic lesions showed that former smoking was significantly associated with early-onset psoriasis (AOR=2.44, P=0.016) but not PsA (AOR=0.59, P=0.329). Laboratory test indicated that both PsA and psoriasis were associated with altered lipid profile.

Conclusion

PsA and psoriasis in Chinese patients share common behavioral and cardiometabolic risk factors including dyslipidemia and alcohol consumption. There is a U-shape association between BMI and PsA/psoriasis.

Psoriasis and Gut Microbiome-Current State of Art

Psoriasis is a chronic, immune-mediated inflammatory disease that affects around 125 million people worldwide. Several studies concerning the gut microbiota composition and its role in disease pathogenesis recently demonstrated significant alterations among psoriatic patients. Certain parameters such as Firmicutes/Bacteroidetes ratio or Psoriasis Microbiome Index were developed in order to distinguish between psoriatic and healthy individuals. The “leaky gut syndrome” and bacterial translocation is considered by some authors as a triggering factor for the onset of the disease, as it promotes chronic systemic inflammation. The alterations were also found to resemble those in inflammatory bowel diseases, obesity and certain cardiovascular diseases. Microbiota dysbiosis, depletion in SCFAs production, increased amount of produced TMAO, dysregulation of the pathways affecting the balance between lymphocytes populations seem to be the most significant findings concerning gut physiology in psoriatic patients. The gut microbiota may serve as a potential response-to-treatment biomarker in certain cases of biological treatment. Oral probiotics administration as well as fecal microbial transplantation were most reported in bringing health benefits to psoriatic patients. However, the issue of psoriatic bacterial gut composition, its role and healing potential needs further investigation. Here we reviewed the literature on the current state of the relationship between psoriasis and gut microbiome.

Pathophysiology of psoriasis: A review

Psoriasis is a complex chronic inflammatory skin disease caused by the dynamic interplay between multiple genetic risk foci, environmental risk factors, and excessive immunological abnormalities. Psoriasis affects approximately 2% of the population worldwide, and dramatic advances have been achieved in the understanding and treatment options for psoriasis. Recent progress in biological therapies has revealed the fundamental roles of tumor necrosis factor-α, interleukin (IL)-23p19, and the IL-17A axis together with skin-resident immune cells and major signal transduction pathways in the pathogenesis of psoriasis. In addition to IL-17-producing T helper17 cells, innate lymphoid cell (ILC)3 induces psoriasis rashes directly without T-cell/antigen interaction in response to the released antimicrobial peptides from activated keratinocytes and inflammatory cytokines. ILC3 typically expresses retinoic acid receptor-related orphan receptor gamma t in the nucleus, matures in the presence of IL-7 and IL-23, and produces IL-17 and IL-22. The number of ILC3s is increased in the blood, psoriasis rash, and even in nonrash areas of psoriatic skin. Psoriasis is significantly associated with cardiovascular disease, metabolic syndrome, and inflammatory disorders, particularly the severe type. The similarity of enterobacteria in the psoriasis gut to that in diabetic patients may be related to its pathogenesis. In the current review, we focus on the pathophysiology of psoriasis in the accelerated immunological inflammatory loop, danger signal from keratinocytes, and cytokines, particularly IL-17 and IL-23p19. In addition, pathophysiological speculation with regard to morphology has been supplemented. Finally, the differences and similarities between psoriasis and atopic dermatitis are discussed.

A Novel Evaluation System of Psoriasis Curative Effect Based on Bayesian Maximum Entropy Weight Self-Learning and Extended Set Pair Analysis

BACKGROUND

Psoriasis is a complex skin disease and difficult to evaluate, and this study aimed to provide an objective and systematic approach for evaluating the efficacy of psoriasis.

METHODS

We sought to construct a Bayesian network from sixteen indicators in four aspects of psoriasis (skin lesion conditions, laboratory indexes, quality of life, and accompanying symptoms) and obtained weights of each index by combining the analytic hierarchy process with maximum entropy self-learning. Furthermore, we adopted stability analysis to calculate the minimum sample size of the system. The extended set pair analysis was utilized to evaluate the efficacy based on improved weights, which overcomes the limitation of set pair analysis (unable to evaluate the efficacy with uncertain grades and thresholds).

RESULTS

A total of 100 psoriasis vulgaris patients were included to evaluate the curative effect by the system. We obtained the weights of each index and the Euclidean distance for efficacy evaluation of 100 patients. The sensitivity analysis proved that the results had no significant change with the variation of single patient's indexes, which indicated that our results were stable to assess the effectiveness.

CONCLUSIONS

We provided an available method of comprehensive effective evaluation of various indicators of psoriasis and based on both subjective and objective weights.

Alterations of the Skin and Gut Microbiome in Psoriasis and Psoriatic Arthritis

Numerous scientific studies in recent years have shown significant skin and gut dysbiosis among patients with psoriasis. A significant decrease in microbiome alpha-diversity (abundance of different bacterial taxa measured in one sample) as well as beta-diversity (microbial diversity in different samples) was noted in psoriasis skin. It has been proven that the representation of Cutibacterium, Burkholderia spp., and Lactobacilli is decreased and Corynebacterium kroppenstedii, Corynebacterium simulans, Neisseria spp., and Finegoldia spp. increased in the psoriasis skin in comparison to healthy skin. Alterations in the gut microbiome in psoriasis are similar to those observed in patients with inflammatory bowel disease. In those two diseases, the F. prausnitzii, Bifidobacterium spp., Lactobacillus spp., Parabacteroides and Coprobacillus were underrepresented, while the abundance of Salmonella sp., Campylobacter sp., Helicobacter sp., Escherichia coli, Alcaligenes sp., and Mycobacterium sp. was increased. Several research studies provided evidence for the significant influence of psoriasis treatments on the skin and gut microbiome and a positive influence of orally administered probiotics on the course of this dermatosis. Further research is needed to determine the influence of the microbiome on the development of inflammatory skin diseases. The changes in microbiome under psoriasis treatment can serve as a potential biomarker of positive response to the administered therapy.

Deciphering Gut Microbiota Dysbiosis and Corresponding Genetic and Metabolic Dysregulation in Psoriasis Patients Using Metagenomics Sequencing

Background

Increasing evidence has shown that alterations in the intestinal microbiota play an important role in the pathogenesis of psoriasis. The existing relevant studies focus on 16S rRNA gene sequencing, but in-depth research on gene functions and comprehensive identification of microbiota is lacking.

Objectives

To comprehensively identify characteristic gut microbial compositions, genetic functions and relative metabolites of patients with psoriasis and to reveal the potential pathogenesis of psoriasis.

Methods

DNA was extracted from the faecal microbiota of 30 psoriatic patients and 15 healthy subjects, and metagenomics sequencing and bioinformatic analyses were performed. The Kyoto Encyclopedia of Genes and Genomes (KEGG) database, cluster of orthologous groups (COG) annotations, and metabolic analyses were used to indicate relative target genes and pathways to reveal the pathogenesis of psoriasis.

Results

Compared with healthy individuals, the gut microbiota of psoriasis patients displayed an alteration in microbial taxa distribution, but no significant difference in microbial diversity. A distinct gut microbial composition in patients with psoriasis was observed, with an increased abundance of the phyla Firmicutes, Actinobacteria and Verrucomicrobia and genera Faecalibacterium, Bacteroides, Bifidobacterium, Megamonas and Roseburia and a decreased abundance of the phyla Bacteroidetes, Euryarchaeota and Proteobacteria and genera Prevotella, Alistipes, and Eubacterium. A total of 134 COGs were predicted with functional analysis, and 15 KEGG pathways, including lipopolysaccharide (LPS) biosynthesis, WNT signaling, apoptosis, bacterial secretion system, and phosphotransferase system, were significantly enriched in psoriasis patients. Five metabolites, hydrogen sulfide (H₂S), isovalerate, isobutyrate, hyaluronan and hemicellulose, were significantly dysregulated in the psoriatic cohort. The dysbiosis of gut microbiota, enriched pathways and dysregulated metabolites are relevant to immune and inflammatory response, apoptosis, the vascular endothelial growth factor (VEGF) signaling pathway, gut-brain axis and brain-skin axis that play important roles in the pathogenesis of psoriasis.

Conclusions

A clear dysbiosis was displayed in the gut microbiota profile, genetic functions and relative metabolites of psoriasis patients. This study is beneficial for further understanding the inflammatory pathogenesis of psoriasis and could be used to develop microbiome-based predictions and therapeutic approaches.

Implication of Human Bacterial Gut Microbiota on Immune-Mediated and Autoimmune Dermatological Diseases and Their Comorbidities: A Narrative Review

During the last decade, the advent of modern sequencing methods (next generation techniques, NGS) has helped describe the composition of the human gut microbiome, enabling us to understand the main characteristics of a healthy gut microbiome and, conversely, the magnitude of its disease-related changes. This new knowledge has revealed that healthy gut microbiota allow the maintenance of several crucial physiological functions, such as the ability to regulate the innate and adaptive immune systems. Increasing evidence has pointed out a condition of dysbiosis in several autoimmune/immune mediated dermatological conditions and specific gut microbial signatures have also been reported to correlate with clinical and prognostic parameters of such diseases. Based on a literature search of relevant published articles, this review debates the current knowledge and the possible pathogenic implications of bacterial gut microbiota composition assessed through NGS techniques in systemic lupus erythematosus, atopic dermatitis, psoriasis, and alopecia areata. Evidence of a potential role of specific gut microbiota signatures in modulating the clinical course of such diseases and their main comorbidities has been also reviewed.

Heat-Treated Bifidobacterium longum CECT-7347: A Whole-Cell Postbiotic with Antioxidant, Anti-Inflammatory, and Gut-Barrier Protection Properties

Non-viable preparations of probiotics, as whole-cell postbiotics, attract increasing interest because of their intrinsic technological stability, and their functional properties, such as immune system modulation, gut barrier maintenance, and protection against pathogens. However, reports on Bifidobacteria-derived postbiotics remain scarce. This study aims to demonstrate the functional properties of a heat-treated (HT), non-viable, Bifidobacterium longum strain, CECT-7347, a strain previously selected for its anti-inflammatory phenotype and ability to improve biomarkers of intestinal integrity in clinical trials. The study used the nematode Caenorhabditis elegans and HT-29 cell cultures as eukaryotic model systems. Our results show that HT-CECT-7347 preserves the capacity to protect against oxidative stress damage, while it also reduces acute inflammatory response and gut-barrier disruption, and inhibits bacterial colonization, by activating pathways related to innate immune function. These findings highlight the interest of the ingredient as a novel postbiotic and pave the way to broaden the range of HT-CECT-7347 applications in gut health.

Dysbiosis of gut microbiota and its correlation with dysregulation of cytokines in psoriasis patients

Background

Psoriasis is an inflammatory skin disease associated with multiple comorbidities and substantially diminishes patients’ quality of life. The gut microbiome has become a hot topic in psoriasis as it has been shown to affect both allergy and autoimmunity diseases in recent studies. Our objective was to identify differences in the fecal microbial composition of patients with psoriasis compared with healthy individuals to unravel the microbiota profiling in this autoimmune disease.

Results

We collected fecal samples from 30 psoriasis patients and 30 healthy controls, sequenced them by 16S rRNA high-throughput sequencing, and identified the gut microbial composition using bioinformatic analyses including Quantitative Insights into Microbial Ecology (QIIME) and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). Our results showed that different relative abundance of certain bacterial taxa between psoriasis patients and healthy individuals, including Faecalibacterium and Megamonas, were increased in patients with psoriasis. It’s also implicated that many cytokines act as main effect molecules in the pathology of psoriasis. We selected the inflammation-related indicators that were abnormal in psoriasis patients and found the microbiome variations were associated with the level of them, especially interleukin-2 receptor showed a positive relationship with Phascolarctobacterium and a negative relationship with the Dialister. The relative abundance of Phascolarctobacterium and Dialister can be regard as predictors of psoriasis activity. The correlation analysis based on microbiota and Inflammation-related indicators showed that microbiota dysbiosis might induce an abnormal immune response in psoriasis.

Conclusions

We concluded that the gut microbiome composition in psoriasis patients has been altered markedly and provides evidence to understand the relationship between gut microbiota and psoriasis. More mechanistic experiments are needed to determine whether the differences observed in gut microbiota are the cause or consequences of psoriasis and whether the relationship between gut microbiota and cytokines was involved.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02125-1.

Impact of diet and the bacterial microbiome on the mucous barrier and immune disorders

The prevalence of chronic immune and metabolic disorders is increasing rapidly. In particular, inflammatory bowel diseases, obesity, diabetes, asthma and chronic obstructive pulmonary disease have become major healthcare and economic burdens worldwide. Recent advances in microbiome research have led to significant discoveries of associative links between alterations in the microbiome and health, as well as these chronic supposedly noncommunicable, immune/metabolic disorders. Importantly, the interplay between diet, microbiome and the mucous barrier in these diseases has gained significant attention. Diet modulates the mucous barrier via alterations in gut microbiota, resulting in either disease onset/exacerbation due to a "poor" diet or protection against disease with a "healthy" diet. In addition, many mucosa-associated disorders possess a specific gut microbiome fingerprint associated with the composition of the mucous barrier, which is further influenced by host-microbiome and inter-microbial interactions, dietary choices, microbe immigration and antimicrobials. Our review focuses on the interactions of diet (macronutrients and micronutrients), gut microbiota and mucous barriers (gastrointestinal and respiratory tract) and their importance in the onset and/or progression of major immune/metabolic disorders. We also highlight the key mechanisms that could be targeted therapeutically to prevent and/or treat these disorders.

Gut-Skin Axis: Current Knowledge of the Interrelationship between Microbial Dysbiosis and Skin Conditions

The microbiome plays an important role in a wide variety of skin disorders. Not only is the skin microbiome altered, but also surprisingly many skin diseases are accompanied by an altered gut microbiome. The microbiome is a key regulator for the immune system, as it aims to maintain homeostasis by communicating with tissues and organs in a bidirectional manner. Hence, dysbiosis in the skin and/or gut microbiome is associated with an altered immune response, promoting the development of skin diseases, such as atopic dermatitis, psoriasis, acne vulgaris, dandruff, and even skin cancer. Here, we focus on the associations between the microbiome, diet, metabolites, and immune responses in skin pathologies. This review describes an exhaustive list of common skin conditions with associated dysbiosis in the skin microbiome as well as the current body of evidence on gut microbiome dysbiosis, dietary links, and their interplay with skin conditions. An enhanced understanding of the local skin and gut microbiome including the underlying mechanisms is necessary to shed light on the microbial involvement in human skin diseases and to develop new therapeutic approaches.

Insights into interplay of immunopathophysiological events and molecular mechanistic cascades in psoriasis and its associated comorbidities

Psoriasis is an inflammatory skin disease with complex pathogenesis and multiple etiological factors. Besides the essential role of autoreactive T cells and constellation of cytokines, the discovery of IL-23/Th17 axis as a central signaling pathway has unraveled the mechanism of accelerated inflammation in psoriasis. This has provided insights into psoriasis pathogenesis and revolutionized the development of effective biological therapies. Moreover, genome-wide association studies have identified several candidate genes and susceptibility loci associated with this disease. Although involvement of cellular innate and adaptive immune responses and dysregulation of immune cells have been implicated in psoriasis initiation and maintenance, there is still a lack of unifying mechanism for understanding the pathogenesis of this disease. Emerging evidence suggests that psoriasis is a high-mortality disease with additional burden of comorbidities, which adversely affects the treatment response and overall quality of life of patients. Furthermore, changing trends of psoriasis-associated comorbidities and shared patterns of genetic susceptibility, risk factors and pathophysiological mechanisms manifest psoriasis as a multifactorial systemic disease. This review highlights the recent progress in understanding the crucial role of different immune cells, proinflammatory cytokines and microRNAs in psoriasis pathogenesis. In addition, we comprehensively discuss the involvement of various complex signaling pathways and their interplay with immune cell markers to comprehend the underlying pathophysiological mechanism, which may lead to exploration of new therapeutic targets and development of novel treatment strategies to reduce the disastrous nature of psoriasis and associated comorbidities.

Gut microbiome profile in psoriatic patients treated and untreated with biologic therapy

There are increasing data about the role of the gut microbiome in various autoimmune diseases, including psoriasis, a chronic inflammatory and immune-mediated disease. Current treatment strategies in psoriasis include immunomodulating biologic agents. A variable response to this type of therapy has been reported in psoriatic patients. A possible effect of biologic therapy on the gut microbiome composition has been suggested, but data are still limited. The aim of this study was to compare the gut microbiome composition between psoriatic patients treated and untreated with biologic drugs in order to identify differences which may highlight the potential impact of the treatment on the gut microbiome. 16S rRNA sequencing and bioinformatic analyses were performed on the fecal samples of 30 psoriatic patients with similar clinicopathological features, 10 of whom were undergoing biologic therapy and 20 not receiving systemic therapy. Alpha and beta diversity significantly differed between the two groups of patients. A reduced bacterial biodiversity in the group of treated patients compared with the group of untreated patients was observed. Differential relative abundances of key gut microbial communities, including Akkermansia muciniphila and Bacteroides plebeius, were identified between the two groups of patients. This study showed that biologic therapy may have an impact on the composition of the gut microbiome of psoriatic patients. Gut microbiome composition could be used as an indicator of response to therapy and the modulation of the microbial composition could help to restore the intestinal symbiosis in psoriatic patients.

Clinical Implications of Intestinal Barrier Damage in Psoriasis

Background

An increasing amount of evidence suggests an association between increased intestinal permeability and the pathogenesis of chronic inflammatory diseases. However, the clinical significance of gut barrier dysfunction in psoriasis remains to be established.

Objective

To evaluate whether there are differences in disease activity, the severity of gastrointestinal symptoms and the blood concentration of bacterial metabolites in psoriatic patients with a normal and altered intestinal barrier.

Patients and Methods

Gut barrier integrity was assessed with the serum concentrations of claudin-3, a modulator of intestinal tight junctions and an intestinal fatty acid-binding protein, a marker of enterocyte damage. Gastrointestinal symptoms were evaluated with a validated questionnaire. The concentration of trimethylamine N-oxide (TMAO), a gut microbiota-associated metabolite, was measured with high-performance liquid chromatography.

Results

One hundred and fourteen patients with psoriasis were finally enrolled in the study – 68 with an altered gut barrier and 46 with a properly functioning intestinal barrier. Patients with an altered gut barrier showed a significantly higher score in the Gastrointestinal Symptom Rating Scale (3.20 vs 1.46, p<0.001). Moreover, patients with psoriasis and a disrupted intestinal barrier demonstrated a higher disease activity (PASI: 19.7 vs 10.3, p<0.001) and systemic inflammatory parameters (neutrophil-to-lymphocyte ratio: 2.86 vs 1.71, p<0.001; C-reactive protein 3.76 vs 1.92; p<0.05). The marker of bacterial translocation was significantly higher in psoriatic patients with damaged gut integrity (TMAO: 375.7±51.9 vs 119.4±27.5 ng/mL; p<0.05).

Conclusion

The altered gut barrier in psoriasis is associated with gastrointestinal symptoms, systemic inflammatory profile and the increased blood concentration of gut microbiota-derived metabolite – TMAO. Intestinal barrier modulation represents a new promising therapeutic approach.

Sleep and the gut microbiome in psoriasis: clinical implications for disease progression and the development of cardiometabolic comorbidities

Background

Sleep dysfunction and sleep disorders are important comorbidities of psoriasis. Not only do these sleep comorbidities contribute to reduced quality of life, but they may also lead to worsening psoriasis and increased susceptibility to cardiometabolic diseases. While psoriasis and sleep dysfunction are thought to be linked by itch, depression, and immune system dysregulation, the relationship between psoriasis and sleep dysfunction is not yet fully understood.

Objective

We sought to compare previous studies characterizing the gut microbiome in psoriasis and sleep dysfunction and examine the potential relevance of shared findings on cardiometabolic and overall health.

Methods

We performed literature searches of PubMed and Embase databases to find studies evaluating the gut microbiome in psoriasis, sleep dysfunction, and cardiometabolic diseases.

Results

Studies characterizing the gut microbiome in psoriasis and sleep dysfunction reveal shared findings, specifically an increased Firmicutes to Bacteroidetes ratio and reduced abundance of short chain fatty acid-producing bacteria. These dysbiotic features have also been shown to promote systemic inflammation and cardiometabolic disease.

Conclusion

In favoring an increased Firmicutes to Bacteroidetes ratio and reduced abundance of short chain fatty acid-producing bacteria, sleep dysfunction could be contributing to worsening psoriasis and cardiometabolic comorbidities through intestinal dysbiosis. Future studies are needed to determine whether gut- and sleep-targeting interventions could be therapeutic in psoriasis patients with poor sleep.

Treg Cells and Epigenetic Regulation

The discovery of the epigenetic regulation of Treg cells, a cell population with fundamental immunoregulatory properties, has shed considerable insights into an understanding of the role of these cells in health and disease. Research over the past several years has shown that the interaction of Treg cells with the gut microbiota are critical not only for the development of Treg function in health but also for abnormalities of Treg function that play a critical role in the pathogenesis of human diseases such as the allergic diseases, the autoimmune disorders, and cancer. The equilibrium between phenotypic plasticity and stability of Treg cells is defined by the fine-tuned transcriptional and epigenetic events required to ensure stable expression of Foxp3 in Treg cells. In this chapter, we discuss the molecular events that control Foxp3 gene expression and address the importance of DNA methylation as an important molecular switch that regulates the genetic expression of Treg induction and the possible implications of these findings for the treatment of human diseases characterized by abnormalities of Treg cell function.

Skin and Gut Microbiome in Psoriasis: Gaining Insight Into the Pathophysiology of It and Finding Novel Therapeutic Strategies

Psoriasis affects the health of myriad populations around the world. The pathogenesis is multifactorial, and the exact driving factor remains unclear. This condition arises from the interaction between hyperproliferative keratinocytes and infiltrating immune cells, with poor prognosis and high recurrence. Better clinical treatments remain to be explored. There is much evidence that alterations in the skin and intestinal microbiome play an important role in the pathogenesis of psoriasis, and restoration of the microbiome is a promising preventive and therapeutic strategy for psoriasis. Herein, we have reviewed recent studies on the psoriasis-related microbiome in an attempt to confidently identify the “core” microbiome of psoriasis patients, understand the role of microbiome in the pathogenesis of psoriasis, and explore new therapeutic strategies for psoriasis through microbial intervention.

Infantile infection and antibiotic exposure in association with pediatric psoriasis development: A nationwide nested case-control study

BACKGROUND

Microbiol dysbiosis and antibiotic exposure have been implicated in the pathogenesis of pediatric inflammatory diseases.

OBJECTIVES

To investigate the impacts of infantile infection and antibiotic exposure on pediatric psoriasis development.

METHODS

This is a nationwide nested case-control study. From the National Health Insurance Research Database of Taiwan, a total of 1527 patients with pediatric psoriasis were identified and matched with 15,270 reference individuals without psoriasis, for the period of 2000 to 2017. Demographic characteristics and comorbidities were compared. Conditional stepwise logistic regression analysis was conducted to examine the associations.

RESULTS

The mean ages were 9.9 ± 3.7 years in both groups. Atopic dermatitis (adjusted odds ratio [aOR], 2.07; 95% confidence interval [CI], 1.84-2.32) and family history of psoriasis, especially of the mother (aOR, 9.86; 95% CI, 6.89-14.10) or other first-degree relatives (aOR, 5.49; 95% CI, 3.91-7.70), were independently associated with pediatric psoriasis on multivariate analyses. Skin viral and bacterial infections (aOR, 1.35; 95% CI, 1.13-1.62) and fungal infections (aOR, 1.71; 95% CI, 1.44-2.04) in the first 2 years of life were significantly associated with pediatric psoriasis. Systemic antibiotic exposure was not. These results were consistent at different time periods across sensitivity analyses.

LIMITATION

Information about diet and lifestyle was not available.

CONCLUSION

Skin infections at an early age were associated with pediatric psoriasis development.

Gut-Brain-Skin Axis in Psoriasis: A Review

Introduction

Psoriasis is a common skin disease, with chronic inflammation and a complex etiology. It has long been recognized that chronic skin conditions and mental health disorders are often co-morbid. Thus, the concept of the gut–brain–skin axis emphasized in mental health disorders may also regulate the health of skin.

Results

The gut microbiota has been found to be the bridge between the immune system and nervous system. By leveraging clinical cases and animal models of psoriasis, an important communication pathway has been identified along the gut–brain–skin axis that is associated with the modulation of neurotransmitters from the microbiota. Furthermore, mammalian neurotransmitters, including dopamine, serotonin, or γ-aminobutyric acid (GABA), can be produced and/or consumed by several types of bacteria. Other studies suggest that manipulating these neurotransmitters by bacteria may have an effect on host physiology, and the levels of neurotransmitter can be altered by microbiota-based interventions.

Conclusions

Nonetheless, it is unknown whether or not the manipulation of neurotransmitter levels by bacteria can affect the occurrence and development of psoriasis. Notably, preliminary experiments found that oral consumption of probiotics improves the clinical symptoms in patients with psoriasis, perhaps correlated with the gut microbiome-mediated crosstalk between the immune system and the nervous system by secreting neurotransmitters in psoriasis. In this review, the communication along the gut–brain–skin axis is discussed.

Relationship between intestinal microbiota, diet and biological systems: an integrated view

The health-disease process can be influenced by the intestinal microbiota. As this plays a fundamental role in protecting the organism, the importance of studying the composition and diversity of this community becomes increasingly evident. Changes in the composition of the intestinal bacterial community may result in dysbiosis, and this process may contribute to triggering various diseases in all biological systems. This imbalance of intestinal microbiota homeostasis may alter commensal bacteria and the host metabolism, as well as immune function. Dysbiosis also causes an increase in intestinal permeability due to exposure to molecular patterns associated with the pathogen and lipopolysaccharides, leading to a chronic inflammatory process that can result in diseases for all biological systems. In this context, dietary intervention through the use of probiotics, prebiotics and antioxidant foods can be considered a contribution to the modulation of intestinal microbiota. Probiotics have been used to provide up to 10 billion colony forming units, and probiotic foods, Kefir and fermented natural yogurt are also used. Prebiotics, in turn, are found in supplemental formulations of processed foods and in functional foods that are also sources of phenolic compounds, such as flavonoids, antioxidant and anti-inflammatory substances, polyunsaturated fatty acids, vitamins, and minerals. In this review, we will discuss the relationship between an imbalance in the intestinal microbiota with the development of diseases, besides indicating the need for future studies that can establish bacterial parameters for the gastrointestinal tract by modulating the intestinal microbiota, associated with the adoption of healthy habits during all life cycles.