Short-Term Exposure to a Western Diet Induces Psoriasiform Dermatitis by Promoting Accumulation of IL-17A-Producing γδ T Cells

The Role of Bile Acid in Immune-Mediated Skin Diseases

Immune-mediated skin disorders arise from dysfunctional immune responses, instigating inflammatory dermatoses and a reduced quality of life. The complex pathogenesis likely involves genetic risks, environmental triggers and aberrant immune activation. An emerging body of evidence suggests that bile acid disturbances may critically promote immune pathology in certain skin conditions. Bile acids synthesised from cholesterol regulate nutrient metabolism and immune cell function via nuclear receptors and G protein-coupled receptors (GPCRs). Altered bile acid profiles and receptor expression have been identified in psoriasis, atopic dermatitis (AD) and autoimmune blistering diseases. Disruptions in bile acid signalling affect the inflammatory and metabolic pathways linked to these disorders. Targeting components of the bile acid axis represents a promising therapeutic strategy. This review elucidates the intricate links between bile acid homeostasis and immune dysfunction in inflammatory skin diseases, synthesising evidence that targeting bile acid pathways may unlock innovative therapeutic avenues. This study compiles clinical and experimental data revealing disrupted bile acid signalling and composition in various immune-mediated dermatoses, highlighting the emerging significance of bile acids in cutaneous immune regulation.

BMI matters: understanding the link between weight and severe psoriasis

This study aims to investigate the causal relationship between Body Mass Index (BMI) and the severity of Psoriasis (PsO) using bidirectional Mendelian Randomization (MR) and regression analyses. We conducted a multicenter study which combined bidirectional MR analyses with regression analyses. The MR analyses included 366,776 individuals from the largest up-to-date published BMI Genome-Wide Association Study (GWAS) data. Regression analyses were performed on 1,979 patients with psoriasis from 12 participating centers (from October 31, 2019, to May 31, 2022). We assessed the impact of BMI on PsO severity using odds ratios (ORs) and regression coefficients for three key measures: the Psoriasis Area and Severity Index (PASI), Body Surface Area (BSA), and Dermatology Life Quality Index (DLQI). Two independent MR analyses revealed a significant causal association between BMI and PsO development. The first MR1 analysis showed that an increased BMI is significantly associated with a higher risk of psoriasis, with odds ratios of 2.28 (95% CI 1.33-3.92; p = 0.003). A subsequent MR2 analysis yielded consistent results, presenting an odds ratio of 2.37 (95% CI 1.16-4.85; p = 0.018) using the inverse-variance weighted method. Logistic regression showed that for every 1-unit increase in BMI (unadjusted covariates), the risk of severe psoriasis (PASI ≥ 10, BSA ≥ 10%, DLQI ≥ 10) increased by 6%, 6%, and 3%, respectively. Linear regression analysis revealed that each unit increase in BMI (not standardised) was associated with an increase of 0.25 units in the mean PASI score (p < 0.001), 0.34 units in the BSA score (p = 0.001), and 0.14 units in the DLQI score (95% CI 0.05-0.23; p = 0.001). From both the genetic and clinical severity assessment perspectives, it has been verified that abnormal weight gain is correlated with the severity of the condition in psoriasis patients. Clinicians should prioritize weight management and nutritional balance in the management of psoriatic disease. Clinicaltrials.gov: ChiCTR1900024852, date of registration: 2019-07-31.

Gut bacterial sphingolipid production modulates dysregulated skin lipid homeostasis

Sphingolipids are an essential lipid component of the skin barrier with alterations in skin sphingolipid composition associated with multiple skin disorders including psoriasis, atopic dermatitis, and ichthyosis. Contributions to skin sphingolipid abundance are not well characterized, thus the main method of modulating skin lipid levels is the topical application of creams rich with sphingolipids at the skin surface. Evidence that diet and gut microbiome function can alter skin biology proposes an intriguing potential for the modulation of skin lipid homeostasis through gut microbial metabolism, but potential mechanisms of action are not well understood. Sphingolipid synthesis by prominent gut microbes has been shown to affect intestinal, hepatic and immune functions with the potential for sphingolipid-producing bacteria to affect skin biology through altering skin sphingolipid levels. To address this question, we used bioorthogonal chemistry to label lipids from the sphingolipid-producing bacteria Bacteroides thetaiotaomicron and trace these lipids to the skin epidermis. Exposing mice to B. thetaiotaomicron strains mutant in the ability to produce sphingolipids resulted in significantly lower transfer of gut microbiome-derived lipids to the skin, while also altering skin biology and altering expression of skin barrier genes. Measurement of skin ceramide levels, a class of sphingolipids involved in skin barrier function, determined that skin sphingolipid levels were altered in the presence of gut sphingolipid-producing bacteria. Together this work demonstrates that gut bacterial lipids can transfer to the skin and provides a compelling avenue for modulating sphingolipid-dominant compartments of the skin using sphingolipid-producing bacteria of the gut microbiome.

Life's Essential 8, genetic susceptibility and the risk of psoriatic disease: a prospective cohort study

BACKGROUND

Psoriatic disease (PsD) is closely associated with cardiovascular (CV) disease. The Life's Essential 8 (LE8) score is a new metric to assess CV health (CVH), where a higher score indicates better CVH. However, the longitudinal association between LE8 score and the risk of PsD remains uncertain.

OBJECTIVES

To investigate, in a cohort study, the association between LE8 score, genetic susceptibility and the risk of PsD.

METHODS

This cohort study included 261 642 participants in the UK Biobank without PsD at baseline. LE8 comprises eight indicators: diet, physical activity, nicotine exposure, sleep health, body mass index, blood lipids, blood glucose and blood pressure. Cox proportional hazard models were used to examine the association between participants' LE8 scores, genetic risk of PsD and the risk of PsD. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated.

RESULTS

During an average follow-up of 12.3 years, 1501 participants developed PsD. Compared with participants with low LE8 scores, the HRs of developing PsD for those with moderate and high LE8 scores were 0.51 (95% CI 0.43-0.59) and 0.34 (95% CI 0.27-0.42) after adjustments, respectively. Dose-response analysis revealed a linear negative association between continuous LE8 score and the risk of developing PsD (P < 0.001), with no evidence of nonlinear association detected. Genetic susceptibility to PsD did not modify this association (P-interaction = 0.63). Subgroup analyses revealed that women had a more pronounced beneficial association between LE8 scores and PsD risk (P-interaction = 0.02).

CONCLUSIONS

Our study suggests that a higher LE8 score, regardless of genetic risk, is associated with a lower risk of PsD, particularly in women. Consequently, maintaining good CVH status is recommended to prevent PsD and assess associated risks.

The Association Between Life's Essential 8 and Psoriasis in American Adults: A Cross-Sectional NHANES Study

Purpose

Life's Essentials 8 (LE8) is a new indicator developed by the American Heart Association to assess cardiovascular health, including diet, physical activity, nicotine exposure, sleep health, body mass index, blood lipids, blood glucose and blood pressure. And more and more studies have shown that this index can evaluate other diseases, such as chronic kidney disease, abdominal aortic calcification and so on. However, there is no relevant study to evaluate the association between LE8 and psoriasis. The purpose of this study was to investigate the relationship between LE8 and the prevalence of psoriasis in American adults.

Patients and Methods

The data are from the National Health and Nutrition Examination Survey (NHANES) of the United States from 2003 to 2006, 2009 to 2014. Psoriasis was the dependent variable. LE8 is an independent variable and is divided into three levels: high, medium and low. Multivariate logistic regression model was used to explore the relationship between LE8 and psoriasis.

Results

A total of 13430 people were included in this study, including 391 patients with psoriasis and 13039 patients without psoriasis. The prevalence of psoriasis was 2.91%. In the fully adjusted logistic regression model, LE8 score was negatively correlated with psoriasis (OR=0.99; 95% CI, 0.98-0.99, P=0.0003). And this result still exists when LE8 is divided into high, medium and low groups. Compared with the low LE8 group, the high LE8 group had a 61% lower risk of psoriasis (OR=0.39; 95% CI, 0.26-0.57, p <0.0001).

Conclusion

This cross-sectional study suggested that LE8 score was negatively correlated with psoriasis risk.

Effects of Sex and Western Diet on Spatial Lipidomic Profiles for the Hippocampus, Cortex, and Corpus Callosum in Mice Using MALDI MSI

Diet is inextricably linked to human health and biological functionality. Reduced cognitive function among other health issues has been correlated with a western diet (WD) in mouse models, indicating that increases in neurodegeneration could be fueled in part by a poor diet. In this study, we use matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) to spatially map the lipidomic profiles of male and female mice that were fed a high-fat, high-sucrose WD for a period of 7 weeks. Our findings concluded that the cortex and corpus callosum showed significant lipid variation by WD in female mice, while there was little to no variation in the hippocampus, regardless of sex. On the other hand, lipid profiles were significantly affected by sex in all regions. Overall, 83 lipids were putatively identified in the mouse brain; among them, HexCer(40:1;O3) and PE(34:0) were found to have the largest statistical difference based on diet for female mice in the cortex and corpus callosum, respectively. Additional lipid changes are noted and can serve as a metric for understanding the brain's metabolomic response to changes in diet, particularly as it relates to disease.

The spatial impact of a Western diet in enriching Galectin-1-regulated Rho, ECM, and SASP signaling in a novel MASH-HCC mouse model

BACKGROUND

Hepatocellular carcinoma (HCC) arising from metabolic dysfunction-associated steatohepatitis (MASH) presents a significant clinical challenge, particularly given the prevalence of the Western diet (WD). The influence of diet on the tumor microenvironment remains poorly understood. Galectin-1 (Gal-1) is a biomarker for HCC and has a crucial role in liver carcinogenesis. Our previous studies demonstrated that silencing Gal-1 effectively treats mouse HCC. However, the impacts of a WD on Gal-1 signaling on MASH to HCC progression are unknown, and this study addresses these knowledge gaps.

METHODS

We developed a novel MASH-HCC mouse model. Using spatial transcriptomics and multiplex immunohistochemistry (IHC), we studied the effects of a WD on the liver and tumor microenvironment. By modulating Gal-1 expression through silencing and overexpression, we explored the location-specific impacts of WD on Gal-1 signaling.

RESULTS

Pathways such as Rho signaling, extracellular matrix (ECM) remodeling, and senescence-associated secretory phenotypes (SASP) were prominently activated in WD-induced metabolic dysfunction-associated fatty liver disease (MAFLD) and MASH-HCC, compared to healthy livers controls. Furthermore, Rho GTPase effectors, ECM remodeling, neutrophil degranulation, cellular stress, and cell cycle pathways were consistently enriched in human and mouse MASH-HCC. Spatially, these pathways were enriched in the tumor and tumor margins of mouse MASH-HCC. Additionally, there was a notable increase in CD11c and PD-L1-positive cells from non-tumor tissues to the tumor margin and inside the tumor of MASH-HCC, suggesting compromised immune surveillance due to WD intake. Moreover, MASH-HCC exhibited significant Gal-1 induction in N-Cadherin-positive cells, indicating enhanced epithelial-to-mesenchymal transition (EMT). Modulating Gal-1 expression in MASH-HCC further established its specific roles in regulating Rho signaling and SASP in the tumor margin and non-tumor tissues in MASH-HCC.

CONCLUSION

WD intake significantly influences vital cellular processes involved in Gal-1-mediated signaling, including Rho signaling and ECM remodeling, in the tumor microenvironment, thereby contributing to the development of MASH-HCC.

GRAPPA 2023 Basic Science Workshop: What to Expect From Animal Models for Psoriatic Arthritis and Psoriasis

Animal models help to drive research into psoriasis and psoriatic arthritis (PsA), particularly when studies in humans are not feasible. There are no animal models that perfectly mimic psoriatic disease (PsD) and so the pros and cons of each existing model must be considered for appropriate experimental design. Roughly, the existing animal models for PsD can be divided into 4 categories: (1) spontaneous models, (2) transgenic models, (3) inducible models, and (4) xenotransplantation models. Animal models in PsD are extremely important for dissecting and understanding molecular mechanisms of the disease process and for developing novel drugs. Animal models remain highly valuable for research in PsD in 2 scenarios. The first scenario is when complex interventions or analyses are required that are not feasible in humans due to technical, safety, or economic reasons. The second is when well-controlled study environments are required, such as dietary modifications, that would be challenging in humans. This topic was presented as part of the basic science workshops during the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) 2023 annual meeting.

Bile acid signaling in the regulation of whole body metabolic and immunological homeostasis

Bile acids (BAs) play a crucial role in nutrient absorption and act as key regulators of lipid and glucose metabolism and immune homeostasis. Through the enterohepatic circulation, BAs are synthesized, metabolized, and reabsorbed, with a portion entering the vascular circulation and distributing systemically. This allows BAs to interact with receptors in all major organs, leading to organ-organ interactions that regulate both local and global metabolic processes, as well as the immune system. This review focuses on the whole-body effects of BA-mediated metabolic and immunological regulation, including in the brain, heart, liver, intestine, eyes, skin, adipose tissue, and muscle. Targeting BA synthesis and receptor signaling is a promising strategy for the development of novel therapies for various diseases throughout the body.

Clinical Characteristics of Psoriasis Cases Treated by Biologics With an Extended Administration Interval: A Single-Center, Retrospective Observational Study

Background Psoriasis is a chronic inflammatory skin disease with multiple organ manifestations such as arthritis and cardiovascular diseases. While recent therapeutic advancements in systemic biologics have demonstrated efficacy against psoriasis, a complete cure has not been achieved and patients require lifelong treatment to control symptoms. Objective This study aimed to clarify the clinical characteristics of psoriasis patients treated with biologics at an extended interval. Methods This study included patients with psoriasis who were administered biologic therapy for longer than the standard interval (at least a week) and who objectively maintained favorable conditions (static Physician's Global Assessment ≤ 0 to 1). Clinical characteristics, such as body weight (BW), body mass index (BMI), and body fat percentage, were compared to those of patients who were administered biologic therapy at standard intervals. Results Among 162 Japanese patients with psoriasis, 35 were treated with biologics at extended intervals. In the group with extended treatment intervals, patients treated with interleukin (IL)-17 inhibitors (n = 15) presented statistically lower BMI than those treated with IL-23 inhibitors (n = 17) (P < 0.016). The group treated with IL-17 inhibitors at extended intervals showed significantly lower BMI and body fat percentage than the group at standard intervals (P < 0.05). Conclusion Trends in our hospital suggest that psoriasis patients with low BMI and body fat percentage can maintain good status with extended interleukin (IL)-17 inhibitor dosing intervals (static Physician's Global Assessment ≤ 0 to 1).

High glucose intake exacerbates experimental autoimmune prostatitis through mitochondrial reactive oxygen species-dependent TGF-β activation-mediated Th17 differentiation

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a common inflammatory immune disease of the urogenital system. High glucose intake is considered to be a potential promoter of autoimmune diseases. However, the influence of high glucose intake on CP/CPPS is unknown. This research aimed to explore the influences of high glucose intake on experimental autoimmune prostatitis (EAP), a valid animal model of CP/CPPS, and the underlying mechanism. NOD mice received 20% glucose water or normal water treatment during EAP induction. EAP severity and Th17 cell responses were evaluated. Then, we explored the effects of an IL-17A neutralizing antibody, an inhibitor of TGF-β, the reactive oxygen species (ROS) inhibitor NAC, and the mitochondrial ROS (mtROS) antioxidant MitoQ on glucose-fed EAP mice. The results demonstrated that high glucose intake aggravated EAP severity and promoted Th17 cell generation, which could be ameliorated by the neutralization of IL-17A. In vitro experiments showed that high dextrose concentrations promoted Th17 cell differentiation through mtROS-dependent TGF-β activation. Treatment with TGF-β blockade, NAC, or MitoQ suppressed Th17 cell generation both in vivo and in vitro, resulting in the amelioration of EAP manifestations caused by high glucose intake. This study revealed that high glucose intake exacerbates EAP through mtROS-dependent TGF-β activation-mediated Th17 differentiation. Our results may provide insights into the molecular mechanisms underlying the detrimental effects of an environmental factor, such as high glucose intake, on CP/CPPS.

γδ T cells: origin and fate, subsets, diseases and immunotherapy

The intricacy of diseases, shaped by intrinsic processes like immune system exhaustion and hyperactivation, highlights the potential of immune renormalization as a promising strategy in disease treatment. In recent years, our primary focus has centered on γδ T cell-based immunotherapy, particularly pioneering the use of allogeneic Vδ2+ γδ T cells for treating late-stage solid tumors and tuberculosis patients. However, we recognize untapped potential and optimization opportunities to fully harness γδ T cell effector functions in immunotherapy. This review aims to thoroughly examine γδ T cell immunology and its role in diseases. Initially, we elucidate functional differences between γδ T cells and their αβ T cell counterparts. We also provide an overview of major milestones in γδ T cell research since their discovery in 1984. Furthermore, we delve into the intricate biological processes governing their origin, development, fate decisions, and T cell receptor (TCR) rearrangement within the thymus. By examining the mechanisms underlying the anti-tumor functions of distinct γδ T cell subtypes based on γδTCR structure or cytokine release, we emphasize the importance of accurate subtyping in understanding γδ T cell function. We also explore the microenvironment-dependent functions of γδ T cell subsets, particularly in infectious diseases, autoimmune conditions, hematological malignancies, and solid tumors. Finally, we propose future strategies for utilizing allogeneic γδ T cells in tumor immunotherapy. Through this comprehensive review, we aim to provide readers with a holistic understanding of the molecular fundamentals and translational research frontiers of γδ T cells, ultimately contributing to further advancements in harnessing the therapeutic potential of γδ T cells.

Advances in psoriasis and gut microorganisms with co-metabolites

This review summarizes the potential role of gut microbes and their metabolites as novel mediators of psoriasis, including their composition and function in disease pathogenesis, progression, and management. Gut microbiota network analysis, colony construction, and in vivo large-scale interaction experiments showed that different degrees of damage and repair in psoriasis, both in animals and humans, involve cross-border homeostasis of the microbial community. Which gut microbiota interactions are present in psoriasis and how they collaborate with immune cells and influence psoriasis development via the gut-skin axis remain incompletely elucidated. In this article, we review the latest information on the unique patterns of gut microbiota and co-metabolites involved in the pathogenesis of psoriasis and attempt to explore microbial-based therapeutic targets derived from mono-and polymicrobial probiotics, fecal microbiota transplantation, pharmacomicrobiomics, and dietary interventions as diagnostic or therapeutic approaches promising to provide new options and long-term management for psoriasis.

Metabolic influences on T cell in psoriasis: a literature review

Psoriasis is a systemic inflammatory disease that frequently coexists with various other conditions, such as essential hypertension, diabetes, metabolic syndrome, and inflammatory bowel disease. The association between these diseases may be attributed to shared inflammatory pathways and abnormal immunomodulatory mechanisms. Furthermore, metabolites also play a regulatory role in the function of different immune cells involved in psoriasis pathogenesis, particularly T lymphocytes. In this review, we have summarized the current research progress on T cell metabolism in psoriasis, encompassing the regulation of metabolites in glucose metabolism, lipid metabolism, amino acid metabolism, and other pathways within T cells affected by psoriasis. We will also explore the interaction and mechanism between psoriatic metabolites and immune cells. Moreover, we further discussed the research progress of metabolomics in psoriasis to gain a deeper understanding of its pathogenesis and identify potential new therapeutic targets through identification of metabolic biomarkers associated with this condition.

Association Between Diet and Seborrheic Dermatitis: A Case-Control Study

Introduction Seborrheic dermatitis (SD) is a chronic, inflammatory papulosquamous skin disease. The symptoms and signs of SD are typically managed by topical ketoconazole and topical corticosteroids. However, they don't provide a cure for SD, which explains the disease's chronic nature. With this study, we aimed to identify specific dietary modifications that can be implemented as an adjunctive to traditional treatment of SD. Methods A case-control retrospective study. Data was obtained from medical records of patients diagnosed with SD. Patients were invited to participate in an online self-reported questionnaire, and dietary intake was assessed using a validated food frequency questionnaire. The controls were collected by distributing the same questionnaire to healthy adult residents living in Jeddah via social media. Results Two hundred sixty-seven participants were included in the study, 59 of whom were SD patients. Participants who reported consuming the following food types once daily had a higher percentage of SD compared to those without SD: a slice of white bread (p=0.002), a cup of rice or pasta (p<0.001), non-acidic fruits (p=0.014), leafy green vegetables (p=0.007), other types of vegetables (p=0.001), roasted or fried nuts (p=0.047), raw nuts (p=0.022) and a cup of coffee (p=0.041). When asked about their impression of what food types triggered or relieved their disease, 29 (49.2%) of the diseased participants reported no flare-ups with any kind of food. On the other hand, the following food types were commonly reported to be associated with SD exacerbation: spicy food (16.9%), sweets (16.9%), fried food (13.5%), dairy products (11.9%), and citrus fruits (10.2%). In contrast, citrus fruits, leafy green vegetables (8.5% for each), and the other types of vegetables (6.8%) were frequently observed with SD improvement. Conclusion Several dietary factors have been associated with SD in our cohort. Thus, our findings could offer new insights into the application of adjuvant dietary measures that might play a role in the improvement of SD symptoms and potentially enhance therapeutic outcomes.

Impact of Gut Bacterial Metabolites on Psoriasis and Psoriatic Arthritis: Current Status and Future Perspectives

There is growing evidence that supports a role of gut dysbiosis in the pathogenesis of psoriasis (Pso). Thus, probiotic supplementation and fecal microbiota transplantation may serve as promising preventive and therapeutic strategies for patients with Pso. One of the basic mechanisms through which the gut microbiota interacts with the host is through bacteria-derived metabolites, usually intermediate or end products produced by microbial metabolism. In this study, we provide an up-to-date review of the most recent literature on microbial-derived metabolites and highlight their roles in the immune system, with a special focus on Pso and one of its most common comorbidities, psoriatic arthritis.

Co-occurrence of non-alcoholic steatohepatitis exacerbates psoriasis associated with decreased adiponectin expression in a murine model

Introduction

Clinical studies have suggested a bidirectional association between non-alcoholic steatohepatitis (NASH) and psoriasis, affecting each other's development and severity. Here, we explored bidirectional causal linkages between NASH and psoriasis using a murine model.

Methods

NASH was induced in mice by streptozotocin injection at 2 days of age and by high-fat diet feeding (STAM™ model). Psoriasis was induced by topical application of imiquimod (IMQ) on the ear. The severities of liver damage and psoriatic skin changes were determined using histological analysis. Gene expression in the skin tissues was evaluated using quantitative PCR analysis. Serum cytokine levels were determined using enzyme-linked immunosorbent assay. To examine the innate immune responses of normal human epidermal keratinocytes (NHEKs), the cells were treated with interleukin (IL)-17A, tumor necrosis factor (TNF)-α, and AdipoRon, an adiponectin receptor agonist.

Results and Discussion

There were no differences in the degree of liver tissue damage (fat deposition, inflammation, and fibrosis) between NASH mice with and those without psoriasis. Conversely, the co-occurrence of NASH significantly augmented psoriatic skin changes, represented by epidermal hyperplasia, in psoriatic mice. Pro-inflammatory cytokines were expressed in the inflamed skin of psoriatic mice, and the expression of genes, especially Il23a, Il1b, Il36g, and Mip2, was significantly upregulated by the co-occurrence of NASH. The expression of keratinocyte activation marker genes Defb4b and Krt16 was also upregulated by the co-occurrence of NASH. The serum TNF-α and IL-17 levels were increased by the co-occurrence of NASH and psoriasis. The serum adiponectin levels decreased in NASH mice compared with that in non-NASH mice. In NHEK culture, TNF-α and IL-17A synergistically upregulated CXCL1, CXCL8, and IL1B expression. The upregulated pro-inflammatory gene expression was suppressed by AdipoRon treatment, reflecting the anti-inflammatory capacity of adiponectin.

Conclusion

The co-occurrence of NASH exacerbated psoriatic skin changes associated with increased serum inflammatory cytokine levels and decreased serum adiponectin levels. Combined with in vitro findings, increased inflammatory cytokine levels and decreased adiponectin levels likely promote innate immune responses in epidermal keratinocytes in psoriatic skin lesions. Overall, therapeutic intervention for co-occurring NASH is essential to achieve a favorable prognosis of psoriasis in clinical practice.

Insights into Nutritional Strategies in Psoriasis

Psoriasis, an autoimmune chronic inflammatory skin condition, has a high incidence in the general population, reaching 2-4%. Its pathogenesis involves an interplay of genetic factors, immune disturbances, and environmental factors. Within the environmental factors that aid the appearance of this autoimmune skin disease, the Western lifestyle and overall diet play important roles in the steady growth in psoriasis prevalence. Furthermore, psoriasis is associated with comorbidities such as psoriatic arthritis, cardiovascular disease, metabolic syndrome, and obesity. Accumulating evidence suggests that obesity is an important risk factor for psoriasis. Moreover, obesity aggravates established psoriasis, and a reduction in the body mass index can improve the clinical outcomes of psoriasis and increase the efficacy of standard psoriasis therapies. The possible connection between this autoimmune disease and obesity relies on the fact that white adipose tissue is an essential endocrine organ that secretes an array of immune mediators and inflammatory and metabolic factors with pro-inflammatory action. Thus, immune-mediated mechanisms in both psoriasis and obesity conditions are common factors. This paper describes the factors that link obesity with skin autoimmune disease and highlights the importance of the stimulatory or regulatory effects of nutrients and food in psoriasis and the possible improvement of psoriasis through nutritional strategies.

The Emerging Potential of Bile Acids as a Modulator of Psoriatic Inflammation

Background

Bile acids (BAs) are cholesterol-based amphipathic surfactants that are most widely known for their contributions to lipid metabolism, but more recently have been increasingly recognized as a key signaling molecule in inflammatory diseases as well as, potentially, psoriatic disease.

Objective

This brief review reviews relevant literature in order to briefly describe the synthesis of bile acids and their subsequent metabolism and to analyze recent animal and human data that supports anti-inflammatory activity of some BAs in psoriasiform dermatitis.

Methods

Pubmed and other public sources were used to survey the literature relevant to the topic of bile acids and their potential use in psoriasis.

Conclusion

There is clinical and preclinical evidence to support a potential role for BA Supplementation (or modulation BA metabolism and signaling) in the treatment of psoriasis.

Beneficial Effects of Plant-Based Diets on Skin Health and Inflammatory Skin Diseases

The human skin is a crucial organ that protects the organism from the outer environment. Skin integrity and health depend on both extrinsic and intrinsic factors. Intrinsic factors such as aging and genetic background contribute to weakened skin and disease susceptibility. Meanwhile, extrinsic factors including UV radiation, pollution, smoking, humidity, and poor diet also affect skin health and disease. On the other hand, healthy dietary patterns such as plant-based diets have gained popularity as a complementary therapy for skin health. A plant-based diet is defined as all diets based on plant foods, including an abundance of vegetables, fruits, beans, lentils, legumes, nuts, seeds, fungi, and whole grains, with limited or no animal products or processed foods. However, some authors also exclude or limit processed foods in the definition. Recent research has shown that these diets have beneficial effects on inflammatory skin diseases. This review explored the beneficial effects of plant-based diets on inflammatory skin diseases and plant-based functional foods on healthy skin. In conclusion, plant-based diets and plant-based functional foods may have beneficial effects on skin health through the gut microbiome.

Topical histone deacetylase 1 inhibitor Entinostat ameliorates psoriasiform dermatitis through suppression of IL-17A response

BACKGROUND

Biologics against IL-17A, IL-23 and TNF-α achieve a great success in treating psoriasis. However, the majority of patients still have some residual lesions left and require combination therapy to reach complete clearance. Topical medicine is an optional choice but only has limited categories. Besides, drug resistance is very often. Thus, topical medicine targeting new signaling pathway is still in an urgent need in the biologics era.

OBJECTIVE

To investigate the role of topical Entinostat, a selective inhibitor of histone deacetylases 1 (HDAC1) that has been tested in clinic trials to treat solid tumors and hematological malignancies, in psoriasis therapy.

METHODS

Efficacious Entinostat were tested in a mouse imiquimod (IMQ)-induced psoriasiform dermatitis (PsD) model. An in vitro model consisting of human CD4 + T cell, murine T cells and NHEKs were used to screen Entinostat for inhibition of cutaneous inflammatory genes.

RESULTS

Topical application of Entinostat significantly improved psoriasiform inflammation in imiquimod-induced mice model with great reduction of IL-17A+ γδT cell infiltration in skin. Entinostat is powerful agent in inhibition of Th17 cell generation and the expression of psoriasis-related inflammatory mediators by primary keratinocytes upon CD4⁺ T cells stimulation.

CONCLUSION

Our findings suggest Entinostat is a promising topical medicine for psoriasis treatment.

Food, gut barrier dysfunction, and related diseases: A new target for future individualized disease prevention and management

Dysfunction of gut barrier is known as "leaky gut" or increased intestinal permeability. Numerous recent scientific evidences showed the association between gut dysfunction and multiple gastrointestinal tract (GI) and non-GI diseases. Research also demonstrated that food plays a crucial role to cause or remedy gut dysfunction related to diseases. We reviewed recent articles from electronic databases, mainly PubMed. The data were based on animal models, cell models, and human research in vivo and in vitro models. In this comprehensive review, our aim focused on the relationship between dietary factors, intestinal permeability dysfunction, and related diseases. This review synthesizes currently available literature and is discussed in three parts: (a) the mechanism of gut barrier and function, (b) food and dietary supplements that may promote gut health, and food or medication that may alter gut function, and (c) a table that organizes the synthesized information by general mechanisms for diseases related to leaky gut/intestinal permeability and associated dietary influences. With future research, dietary intervention could be a new target for individualized disease prevention and management.

Mendelian Randomization Studies in Psoriasis and Psoriatic Arthritis: A Systematic Review

Psoriasis (PSO) and psoriatic arthritis (PSA) are inflammatory diseases with complex genetic and environmental contributions. Although studies have identified environmental and clinical associations with PSO/PSA, causality is difficult to establish. Mendelian randomization (MR) employs the random assortment of genetic alleles at birth to evaluate the causal impact of exposures. We systematically reviewed 27 MR studies in PSO/PSA examining health behaviors, comorbidities, and biomarkers. Exposures, including smoking, obesity, cardiovascular disease, and Crohn's disease, were causal for PSO and PSA, whereas PSO was causally associated with several comorbidities. These findings provide insights that can guide preventive counseling and precision medicine.

Anti-inflammatory and immunomodulatory effects of polysaccharide extracted from Wuguchong (maggot) on 2,4-dinitrochlorobenzene-induced atopic dermatitis in mice

Atopic dermatitis (AD) is an inflammatory, heterogeneous, chronic skin disorder characterized by recurrent eczematous lesions and intense pruritus, and the pathophysiology mechanism of AD is known for immune dysregulation and inflammatory responses. Wuguchong (maggot) has been widely used in the wound field and found with pharmacological properties of the anti-inflammatory and immunomodulatory function. Recently, some polysaccharides were proven to have beneficial effects on AD skin lesions in mice and humans. However, the effect of the polysaccharide extracted from Wuguchong (PEW) on AD remains to be investigated. In the present study, we examined the anti-inflammatory and immunomodulatory effects of PEW on AD and explored the potential mechanisms. Balb/c mice were orally administrated with PEW to evaluate the therapeutic effect of PEW on 2,4-dinitrochlorobenzene (DNCB)-induced AD. Oral PEW administration significantly ameliorated the lesions and symptoms in AD mice, such as the ear thickness and ear swelling degree, epidermal and dermal thickness, and the infiltration of mast cells. In addition, PEW treatment decreased the levels of serum IgE and histamine, the frequencies of Th1 and Th17 cells, as well as the mRNA expression levels of Th1 and Th17 cytokines and nuclear transcript factors (IFN-γ, T-bet, IL-17A, and ROR-rt). Furthermore, the activation of the NF-κB pathway and the phosphorylation of MAPKs (p38, ERK, and JNK) were significantly suppressed by PEW treatment. Taken together, our study suggests that PEW exerts anti-inflammatory and immunomodulatory effects through inhibition of Th1 and Th17 responses and downregulation of NF-κB and MAPK pathways, PEW would be developed as a promising immune therapy for AD.

Do Sleep Disorders and Western Diet Influence Psoriasis? A Scoping Review

Western diet may trigger sleep disorders and vice versa, but their single and mutual effects on systemic inflammatory diseases (i.e., psoriasis) are far from being fully elucidated. At the same time, psoriatic patients display a great burden of sleep disorders and dysmetabolisms related to an unhealthy lifestyle (i.e., diet). These patients are also affected by a chronic disorder deeply modulated by environmental factors (i.e., sleep and diet) capable to influence drug-response and disease progression. Thus, we aimed to summarize the evidence in the literature that may highlight a potential link among psoriasis-diet-sleep in order to further promote a multidisciplinary approach to psoriatic patients in the scientific community.

Excessive intake of sugar: An accomplice of inflammation

High sugar intake has long been recognized as a potential environmental risk factor for increased incidence of many non-communicable diseases, including obesity, cardiovascular disease, metabolic syndrome, and type 2 diabetes (T2D). Dietary sugars are mainly hexoses, including glucose, fructose, sucrose and High Fructose Corn Syrup (HFCS). These sugars are primarily absorbed in the gut as fructose and glucose. The consumption of high sugar beverages and processed foods has increased significantly over the past 30 years. Here, we summarize the effects of consuming high levels of dietary hexose on rheumatoid arthritis (RA), multiple sclerosis (MS), psoriasis, inflammatory bowel disease (IBD) and low-grade chronic inflammation. Based on these reported findings, we emphasize that dietary sugars and mixed processed foods may be a key factor leading to the occurrence and aggravation of inflammation. We concluded that by revealing the roles that excessive intake of hexose has on the regulation of human inflammatory diseases are fundamental questions that need to be solved urgently. Moreover, close attention should also be paid to the combination of high glucose-mediated immune imbalance and tumor development, and strive to make substantial contributions to reverse tumor immune escape.

Crossbred Sows Fed a Western Diet during Pre-Gestation, Gestation, Lactation, and Post-Lactation Periods Develop Signs of Lean Metabolic Syndrome That Are Partially Attenuated by Spirulina Supplementation

Excessive dietary intake of fats and sugars (“Western diet”, WD) is one of the leading causes of obesity. The consumption of the microalga Arthrospira platensis (spirulina, Sp) is increasing due to its presumed health benefits. Both WD and Sp are also consumed by pregnant and breastfeeding women. This study investigated if gestating and lactating domestic pigs are an appropriate model for WD-induced metabolic disturbances similar to those observed in humans and if Sp supplementation may attenuate any of these adverse effects. Pigs were fed a WD high in fat, sugars, and cholesterol or a control diet. Half of the animals per diet group were supplemented with 20 g Sp per day. The WD did not increase body weight or adipose tissue accumulation but led to metabolic impairments such as higher cholesterol concentration in plasma, lower IGF1 plasma levels, and signs of hepatic damage compared to the control group. Spirulina supplementation could not reduce all the metabolic impairments observed in WD-fed animals. These findings indicate limited suitability of gestating and lactating domestic pigs as a model for WD but a certain potential of low-dose Sp supplementation to partially attenuate negative WD effects.

The Role of Lifestyle and Nutrition in Psoriasis: Current Status of Knowledge and Interventions

Extrinsic environmental factors, including patient lifestyle (alcohol intake, smoking, stress, sleep disturbances, and sedentary habit), diet and single nutrients intake may affect psoriasis clinical presentation, severity, and course. All English language articles dealing with psoriasis and lifestyle factors or diet gathered by an extensive PubMed search were carefully examined in order to explore their impact on the disease. Current authoritative knowledge confirms that low‐calories, Mediterranean, and protein restricted/vegetarian diets may be beneficial. Psoriatic patients are also recommended to engage regular physical activity, to avoid alcohol intake and to consume fish rich in omega‐3 polyunsaturated fatty acids, as well as fruit and vegetables. Prebiotics and probiotics may also provide potential benefit, whereas vitamin D supplementation and gluten‐free diet are useful in selected cases only. Changing of dietary and lifestyle habits alone does not replace conventional treatment, but must be considered as an adjuvant. Physicians may play a crucial role, by adequately acknowledging psoriatic patients on the advantages of proper lifestyle and diet habits as well as providing clues to reliable sources of dietary advice.

Dietary Intervention and Supplements in the Management of Psoriasis: Current Perspectives

Nutrition is a complex topic encompassing diet and a variety of supplements including vitamins, fish oil, herbal products, and probiotics. Patients with psoriasis display high interest in understanding the potential impact of nutritional modifications on their psoriasis. In this review, we examine the evidence for nutritional interventions in psoriasis and summarize important concepts. We found that certain diets, such as low-calorie diets for obese patients, gluten-free diets for patients with comorbid celiac disease, and the Mediterranean diet, may have benefits for psoriasis patients. Supplements in general do not show strong evidence of benefit, though more studies are required given the heterogeneity of these trials. Finally, the gut microbiome has drawn considerable interest in recent years, with specific probiotics showing promising results for psoriasis patients and warranting further exploration.

The role of γδ T cells in the interaction between commensal and pathogenic bacteria in the intestinal mucosa

The intestinal mucosa is an important structure involved in resistance to pathogen infection. It is mainly composed of four barriers, which have different but interrelated functions. Pathogenic bacteria can damage these intestinal mucosal barriers. Here, we mainly review the mechanisms of pathogen damage to biological barriers. Most γδ T cells are located on the surface of the intestinal mucosa, with the ability to migrate and engage in crosstalk with microorganisms. Commensal bacteria are involved in the activation and migration of γδ T cells to monitor the invasion of pathogens. Pathogen invasion alters the migration pattern of γδ T cells. γδ T cells accelerate pathogen clearance and limit opportunistic invasion of commensal bacteria. By discussing these interactions among γδ T cells, commensal bacteria and pathogenic bacteria, we suggest that γδ T cells may link the interactions between commensal bacteria and pathogenic bacteria.

Insights into hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic, debilitating, inflammatory skin disorder with a prevalence of around 1% and a profound impact on patients' quality of life. Characteristic lesions such as inflammatory nodules, abscesses, and sinus tracts develop in the axillae, inguinal, and gluteal areas, typically during or after puberty. A complex interplay of genetic predisposition, hormonal factors, obesity, and smoking contributes to development and maintenance of the disease. HS is considered to arise from an intrinsic defect within the hair follicle, leading to follicular plugging, cyst formation, and subsequent rupture that in turn induce an acute inflammatory response characterized by elevated levels of IL-1β, IL-17, and TNF. Over time, acute lesions transition into chronic disease, with active draining sinus tracts accompanied by extensive fibrosis. HS is associated with other immune-mediated inflammatory diseases, metabolic and cardiovascular disorders, and psychiatric comorbidities. Treatment of HS often requires a combination of antibiotic or immunosuppressing therapies and surgical intervention. Nonetheless, the currently available treatments are not universally effective, and many drugs, which are often repurposed from other inflammatory diseases, are under investigation. Studies into the early stages of HS may yield treatments to prevent disease progression; yet, they are hampered by a lack of appropriate in vitro and animal models.

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.

Processed Food and Atopic Dermatitis: A Pooled Analysis of Three Cross-Sectional Studies in Chinese Adults

Objective: The effect of processed foods on atopic dermatitis (AD) in adults is unclear. This study was to evaluate the association between processed foods and AD in the Chinese adult population.

Design: This study included three population-based cross-sectional studies using cluster sampling by villages, institutions, or factories. Participants underwent dermatological examinations by certificated dermatologists and a food frequency questionnaire survey. A spot urine sample was collected to estimate the daily sodium intake. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were presented as the effect size.

Setting: Shiyan city of Hubei province, and Huayuan, Shimen, Hengyang, Zhuzhou, and Changsha of Hunan province.

Participants: Automobile manufacture workers from Shiyan of Hubei province, and rural residents and civil servants from Hunan.

Results: A total of 15,062 participants, including 3,781 rural residents, 5,111 civil servants, and 6,170 workers, completed all evaluations. Compared to those hardly consumed pickles, consumption of pickles 1–3 times per week was significantly associated with AD (aOR: 1.35; 95% CI: 1.06–1.70). The intake of processed meats 1–3 times per month (aOR: 1.29; 95% CI: 1.05–1.58) and 1–3 times per week (aOR: 1.44; 95% CI: 1.11–1.87) were associated with AD dose-dependently when compared with those who rarely ate processed meats. Compared with non-consumers, the consumption of any processed foods 1–3 times per week (aOR: 1.39; 95% CI: 1.08–1.80) and ≥4 times per week (aOR: 1.41; 95% CI: 1.05–1.89) showed increased risks of AD. A positive association of estimated sodium intake with AD was also observed.

Conclusion: Intake of processed foods is associated with AD in Chinese adults.

Mouse Models of Psoriasis: A Comprehensive Review

The use of preclinical animal models of psoriasis has significantly increased over the last three decades, with each model having unique strengths and limitations. Some models translate better to human disease, and many have provided unique insight into psoriasis disease pathogenesis. In this comprehensive review, we present a comparative description and discussion of genetic mouse models, xenograft approaches, and elicited methods using cytokine injections into and topical imiquimod onto mice. We provide an inclusive list of genetically modified animals that have had imiquimod applied to or cytokines injected into their skin and describe the outcomes of these manipulations. This review will provide a valuable resource for those interested in working with psoriasis animal models.

Fad Diets Past and Present - Including Taurine for Psoriasis, Diet Therapy for Atopic Dermatitis and the Role of Elimination Diets

The impact of diets and foods on cutaneous afflictions has never been a moot point. The number of enquiries from patients and the wider public about how certain foods have impacted upon, or indeed, caused their skin eruption is increasing. While this inquisition is at the forefront of people's and physicians mind in today's modern practice, this has long been a discussion in the scientific world. Metchnikoff alluded to this at the turn of the 20^th century. How foods and certain dietary programs impact on diseases has been postulated, although there is still more to learn, despite the patient's advocacy for a particular dietary regime. The study of the role of the microbiome is increasing. Gut dysbiosis, along with the interaction of the gastrointestinal tract, skin, and brain - gut-skin-brain axis is discussed . The role and impact of neuroendocrine transmitters and the skin are explored.

Homemade Kefir Consumption Improves Skin Condition-A Study Conducted in Healthy and Atopic Volunteers

Diet has a fundamental role in the homeostasis of bodily functions, including the skin, which, as an essential protective barrier, plays a crucial role in this balance. The skin and intestine appear to share a series of indirect metabolic pathways, in a dual relationship known as the “gut-skin axis”. Hence, the gut-skin axis might be receptive to modulation via dietary modification, where probiotics can be included, thus representing a potential therapeutic target in inflammatory skin diseases, such as atopic dermatitis (AD), in order to control and/or ameliorate symptoms. Kefir is one of the most ancient fermented foods, with probiotic characteristics that have been associated with a wide variety of health-promoting benefits, and it presents a microbiological diversity that makes its application as a probiotic in the gut-skin relationship of the utmost interest. However, the impact of a diet containing kefir on skin health has yet to be reported in scientific literature. This study aimed to assess the impact of the intake of homemade kefir in the skin of healthy and atopic volunteers. The intervention resulted in a boost on barrier function in both skin types verified only in the respective kefir intake groups. An improvement in the degree of severity of AD was also confirmed for the kefir intake group. Atopic individuals may benefit from kefir intake, especially in regard to their skin hydration. Finally, the effects observed on skin barrier function in this study probably culminate from the effects of all the ingredients in kefir, including the complex microbiota, its metabolites and macro- and micronutrients resulting from the fermentation. This work opens the way for more advanced research on the impact of the probiotic kefir on cutaneous health, further clarifying its mechanism of action namely via gut-skin axis.

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.

Western Diet and Psoriatic-Like Skin and Joint Diseases: A Potential Role for the Gut Microbiota

Shi et al. (2021) in "Short-term Western diet intake promotes IL-23-mediated skin and joint inflammation accompanied by changes to the gut microbiota in mice" show that Western diet (WD) exacerbates an IL-23 minicircle‒mediated model of psoriasis and psoriatic arthritis, with an expansion of IL-17A‒expressing γδ T cells and shifts to the gut microbial community. WD-associated inflammation is mitigated by diet manipulation or antibiotic administration. These results suggest that dietary manipulation may be useful in the treatment of IL-23‒mediated disease, possibly through the modulation of the gut microbiota.

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.

Short-Term Western Diet Intake Promotes IL-23‒Mediated Skin and Joint Inflammation Accompanied by Changes to the Gut Microbiota in Mice

We previously showed that exposure to a high-sugar and moderate-fat diet (i.e., Western diet [WD]) in mice induces appreciable skin inflammation and enhances the susceptibility to imiquimod-induced psoriasiform dermatitis, suggesting that dietary components may render the skin susceptible to psoriatic inflammation. In this study, utilizing an IL-23 minicircle-based model with features of both psoriasiform dermatitis and psoriatic arthritis, we showed that intake of WD for 10 weeks predisposed mice not only to skin but also to joint inflammation. Both WD-induced skin and joint injuries were associated with an expansion of IL-17A‒producing γδ T cells and increased expression of T helper type 17 cytokines. After IL-23 minicircle delivery, WD-fed mice had reduced microbial diversity and pronounced dysbiosis. Treatment with broad-spectrum antibiotics suppressed IL-23‒mediated skin and joint inflammation in the WD-fed mice. Strikingly, reduced skin and joint inflammation with a partial reversion of the gut microbiota were noted when mice switched from a WD to a standard diet after IL-23 minicircle delivery. These findings reveal that a short-term WD intake‒induced dysbiosis is accompanied by enhanced psoriasis-like skin and joint inflammation. Modifications toward a healthier dietary pattern should be considered in patients with psoriatic skin and/or joint disease.

Dysregulated bile acid receptor-mediated signaling and IL-17A induction are implicated in diet-associated hepatic health and cognitive function

BACKGROUND

Chronic consumption of high sugar and high fat diet associated with liver inflammation and cognitive decline. This paper tests a hypothesis that the development and resolution of diet-induced nonalcoholic fatty liver disease (NAFLD) has an impact on neuroplasticity and cognition.

METHODS

C57BL/6 wild-type mice were fed with either a healthy control diet (CD) or a fructose, palmitate, and cholesterol (FPC)-enriched diet since weaning. When mice were 3-months old, FPC diet-fed mice were randomly assigned to receive either FPC-enriched diet with or without 6% inulin supplementation. At 8 months of age, all three groups of mice were euthanized followed by analysis of inflammatory signaling in the liver and brain, gut microbiota, and cecal metabolites.

RESULTS

Our data showed that FPC diet intake induced hepatic steatosis and inflammation in the liver and brain along with elevated RORγ and IL-17A signaling. Accompanied by microglia activation and reduced hippocampal long-term potentiation, FPC diet intake also reduced postsynaptic density-95 and brain derived neurotrophic factor, whereas inulin supplementation prevented diet-reduced neuroplasticity and the development of NAFLD. In the gut, FPC diet increased Coriobacteriaceae and Erysipelotrichaceae, which are implicated in cholesterol metabolism, and the genus Allobaculum, and inulin supplementation reduced them. Furthermore, FPC diet reduced FXR and TGR5 signaling, and inulin supplementation reversed these changes. Untargeted cecal metabolomics profiling uncovered 273 metabolites, and 104 had significant changes due to FPC diet intake or inulin supplementation. Among the top 10 most affected metabolites, FPC-fed mice had marked increase of zymosterol, a cholesterol biosynthesis metabolite, and reduced 2,8-dihydroxyquinoline, which has known benefits in reducing glucose intolerance; these changes were reversible by inulin supplementation. Additionally, the abundance of Barnesiella, Coprobacter, Clostridium XIVa, and Butyrivibrio were negatively correlated with FPC diet intake and the concentration of cecal zymosterol but positively associated with inulin supplementation, suggesting their benefits.

CONCLUSION

Taken together, the presented data suggest that diet alters the gut microbiota and their metabolites, including bile acids. This will subsequently affect IL-17A signaling, resulting in systemic impacts on both hepatic metabolism and cognitive function.

Association of Pathogenic Th17 Cells with the Disease Severity and Its Potential Implication for Biological Treatment Selection in Psoriasis Patients

Psoriasis is an inflammatory autoimmune disease characterized by cutaneous lesions in plaques. It has been proposed that the immune response has a key role in the disease progression. Particularly, the Th17 cells through IL-17 can contribute to maintain the inflammatory process. The pathogenic Th17 phenotype has been described in human diseases and associated with high severity in inflammatory experimental models. However, it is not clear if the pathogenic phenotype could be present in the skin and peripheral blood as well as its possible association to severity in psoriasis. In the lesional skin, we found high infiltration of Th17 cells and the pathogenic phenotype, finding a correlation between the frequency of Th17 cells and the Psoriasis Area and Severity Index (PASI) score. In peripheral blood, we observed a pool of Th17 lymphocytes with potential to acquire pathogenic features. Interestingly, the percentage of pathogenic Th17 cells (CD4⁺ RORγt⁺ IFN-γ⁺) correlates with disease severity. Moreover, we distinguished three groups of patients based on their IL-17/IFN-γ production by Th17 lymphocytes, which seems to be related with a dynamic or stable potential to express these cytokines. Remarkably, we evaluated the cytokine production by Th17 cells as an immunological marker for the adequate selection of biologic therapy. We found that patients analyzed by this immunological approach and treated with antibodies against IL-17 and TNFα showed great improvement depicted by reduction in PASI and Dermatology Life Quality Index (DLQI) score as well as the percentage of Body Surface Area (BSA). Altogether, our results highlight the importance of the assessment of the pathogenic phenotype in Th17 cells as an immune personalized analysis with the potential to support the therapy choice in the clinical practice.

Nutrition and Psoriasis

Psoriasis is a chronic inflammatory skin disease characterized by accelerated tumor necrosis factor-α/interleukin-23/interleukin-17 axis, hyperproliferation and abnormal differentiation of epidermal keratinocytes. Psoriasis patients are frequently associated with obesity, diabetes, dyslipidemia, cardiovascular diseases, or inflammatory bowel diseases. Psoriasis patients often show unbalanced dietary habits such as higher intake of fat and lower intake of fish or dietary fibers, compared to controls. Such dietary habits might be related to the incidence and severity of psoriasis. Nutrition influences the development and progress of psoriasis and its comorbidities. Saturated fatty acids, simple sugars, red meat, or alcohol exacerbate psoriasis via the activation of nucleotide-binding domain, leucine-rich repeats containing family, pyrin domain-containing-3 inflammasome, tumor necrosis factor-α/interleukin-23/interleukin-17 pathway, reactive oxygen species, prostanoids/leukotrienes, gut dysbiosis or suppression of regulatory T cells, while n-3 polyunsaturated fatty acids, vitamin D, vitamin B12, short chain fatty acids, selenium, genistein, dietary fibers or probiotics ameliorate psoriasis via the suppression of inflammatory pathways above or induction of regulatory T cells. Psoriasis patients are associated with dysbiosis of gut microbiota and the deficiency of vitamin D or selenium. We herein present the update information regarding the stimulatory or regulatory effects of nutrients or food on psoriasis and the possible alleviation of psoriasis by nutritional strategies.

Diet-induced obesity exacerbates imiquimod-mediated psoriasiform dermatitis in anti-PD-1 antibody-treated mice: Implications for patients being treated with checkpoint inhibitors for cancer

BACKGROUND

An ever-increasing number of cancer patients are being treated with checkpoint inhibitors such as anti-PD-1 antibodies, and a small percentage of these patients develop a psoriasis-like skin eruption or severe flares of prior psoriasis.

OBJECTIVE

We investigated the role of obesity in immune checkpoint inhibitors-exacerbated psoriasiform eruption.

METHODS

We fed female C57BL/6 mice a so-called Western diet (WD) or a control diet (CD). Imiquimod (IMQ) was applied topically on ears for 5 consecutive days to induce psoriasiform dermatitis (PsD). Psoriasis-related markers were examined by quantitative real-time PCR. Then we induced PsD in WD- and CD-fed mice in the presence or absence of systemic treatment of anti-PD-1 antibodies to examine if obese mice are more susceptible to anti-PD-1 related PsD than lean mice.

RESULTS

WD-fed mice showed higher baseline mRNA expression levels of psoriasis-associated cytokines such as IL-17, S100A8, and S100A9 compared to mice fed with CD. Furthermore, WD-fed mice had more γδ low (GDL) T cells in the whole skin and higher expression of PD-1 on GDL T cells than CD-fed mice. WD-fed mice receiving anti-PD-1 had more prominent ear swelling than lean mice receiving anti-PD-1 during the 5-day IMQ course (2-fold increase, P < 0.0001 on day 5).

CONCLUSION

WD-induced obesity enhances IMQ-induced psoriasiform inflammation. The finding that WD-fed mice have a more dramatic response to anti-PD-1 than lean mice in terms of IMQ-induced ear swelling suggests that obesity could be a risk factor in the development of psoriasiform eruption during anti-PD-1 therapy.