Psoriasis and inflammatory bowel disease: links and risks

Psoriasis and inflammatory bowel disease: concomitant IMID or paradoxical therapeutic effect? A scoping review on anti-IL-12/23 and anti-IL-23 antibodies

Inflammatory bowel diseases (IBD) and psoriasis are chronic inflammatory conditions belonging to the heterogeneous group of immune-mediated inflammatory diseases (IMIDs). A significant bidirectional link between these two entities has been observed, conditioning an increased risk of IBD in patients with psoriasis and vice-versa. Biological therapies used for IBD may lead to the occurrence of psoriasis as a "paradoxical reaction." The objective of this study is to analyze the current evidence on the association between psoriasis and IBD, particularly finding case reports of the appearance or aggravation of psoriasis under therapy with interleukin-12/23 (IL-12/23) and IL-23 inhibitors. We conducted comprehensive research to identify studies examining the association between psoriasis and IBD and to find case presentations that reported the appearance or aggravation of psoriasis under biologic therapy with IL-12/23 and IL-23 inhibitors up to March 2024. Clinical trials for IL-12/23 and IL-23 inhibitors in IBD were analyzed to find cases of paradoxical psoriasis as registered adverse events. The sources of evidence are PubMed and ClinicalTrials.gov. For each included case report, data on patient characteristics concerning their age, sex, and comorbidities were selected. Moreover, information regarding the indication for biologic therapy, time to onset of paradoxical psoriasis after starting treatment, clinical presentation, and management of the paradoxical psoriasis was extracted. We found 10 reported cases of ustekinumab-induced new-onset or worsening psoriasis and one reported case of paradoxical psoriasis induced by risankizumab in the literature. Four cases of paradoxical psoriasis have been also registered in clinical trials involving ustekinumab treatment in IBD. Psoriasis can constitute a rare paradoxical adverse event of ustekinumab treatment, but further studies are needed to better clarify the cytokine imbalance that leads to this phenomenon induced by inhibition of IL-12/23 and IL-23. Still, few real-world data exist to draw any conclusions, but risankizumab may positively treat psoriasis induced by ustekinumab.

Skin as a Reflection of Gut Health: An Overview of Dermatological Manifestations in Primary Neoplastic and Autoimmune Gastrointestinal Disorders

Gastrointestinal (GI) diseases can present with several extraintestinal manifestations, and cutaneous signs and symptoms are most frequent. Although conventionally GI and skin are considered two entirely separate organ systems, they are closely correlated in origin. An increasing amount of data highlights the complex relationship between GI and dermatological conditions. This review article aims to particularly explore the clinical correlation between neoplastic and autoimmune GI disorders and skin manifestations, which serve as clinical indicators of these diseases. Neoplastic diseases including pancreatic cancer, gastric adenocarcinoma, Muir-Torre syndrome, carcinoid syndrome, and malignant and benign colorectal polyposis syndromes can be accompanied by skin conditions like pancreatic panniculitis, acanthosis nigricans, keratoacanthomas, necrolytic migratory erythema, melanotic macules, oral papillomas and osteomas, respectively. Autoimmune diseases including celiac disease, autoimmune liver conditions and inflammatory bowel disease (IBD) have been linked to dermatological manifestations such as xanthomas, morphea, psoriasis, dermatitis herpetiformis, erythema nodosum and epidermolysis bullosa acquisita. The skin manifestations can precede the GI symptoms and indicate the severity of the underlying condition, serving as a significant diagnostic marker earlier in the disease. Resolution of skin findings can also indicate the efficacy of treatment strategies and provide prognostic utility. Further research is essential to outline the underlying mechanisms linking dermatological and GI diseases and there is an immediate need for collaborative efforts between dermatologists and gastroenterologists.

Mitigative Effects of Topical Norfloxacin on an Imiquimod-Induced Murine Model of Psoriasis

Psoriasis is a chronic, inflammatory dermatosis characterized by thickened, reddened, and scaly skin lesions. Norfloxacin is a fluoroquinolone antibiotic with enhanced antioxidant, anti-inflammatory, and immunomodulatory bioactivities. The aim of this study was to figure out the possible impact of topical norfloxacin on an imiquimod-induced model of psoriasis in mice. Thirty albino-type mice were split into five distinct groups of six animals each. The control group included healthy mice that had not received any treatment. The induction group was given the vehicle 2 h after the topical imiquimod, once daily for 8 days. Two hours after receiving topical imiquimod, the treatment groups including calcipotriol, norfloxacin 2.5%, and norfloxacin 5% were given topical ointments containing calcipotriol 0.005%, norfloxacin 2.5%, and norfloxacin 5%, for 8 days. Topical norfloxacin ointment significantly reduced the severity of imiquimod-exacerbated psoriatic lesions including erythema, shiny-white scaling, and acanthosis and fixed histological abnormalities. Furthermore, imiquimod-subjected mice treated with a higher concentration of norfloxacin ointment exhibited dramatically lower skin levels of inflammation-related biomarkers like IFN-γ, TNF-α, IL-6, IL-17A, IL-23, and TGF-β but higher levels of IL-10. They also demonstrated a notable decrease in angiogenesis parameters such as VEGF and IL-8, a substantial reduction in oxidative indicators like MDA and MPO, and a considerable rise in antioxidant enzymes like SOD and CAT. This study offers novel evidence that norfloxacin may assist in controlling inflammatory dermatoses like psoriasis by minimizing the severity of psoriatic plaques, correcting histological alterations, and diminishing the production of inflammatory, oxidative, and angiogenetic parameters.

The alleviative effects of canagliflozin on imiquimod-induced mouse model of psoriasis-like inflammation

Psoriasis is a life-long immune-mediated dermatosis with thickened, reddish, and flaky skin patches. Canagliflozin is a gliflozin antidiabetic with non-classical remarkable antioxidative, anti-inflammatory, anti-proliferative, and immune-modulating effects. The aim of this study is to examine the probable effects of topical canagliflozin on a mouse model of imiquimod-provoked psoriasis-like dermatitis. The study evaluated 20 Swiss white mice, sorted haphazardly into 4 groups of 5 animals each. Every mouse, with the exception of the control group, had imiquimod applied topically to their shaved backs for 7 days. The control group included healthy mice that were not given any treatment. Mice in the other three groups underwent topical treatment with vehicle (induction group), 0.05% clobetasol propionate ointment (clobetasol group), or 4% canagliflozin emulgel (canagliflozin 4% group) on exactly the same day as imiquimod cream was administered. Topical canagliflozin markedly lowered the intensity of imiquimod-provoked psoriasis eruptions, featuring redness, glossy-white scales, and acanthosis, while also correcting histopathological aberrations. Canagliflozin administration to imiquimod-exposed animals resulted in significantly decreased cutaneous concentrations of inflammatory mediators such as IL-8, IL-17, IL-23, and TNF-α, with raised levels of IL-10. Canagliflozin further lowered proliferative factors involving Ki-67 and PCNA, diminished oxidative indicators such as MDA and MPO, and augmented the activity of antioxidant markers, notably SOD and CAT. Canagliflozin might alleviate the imiquimod-induced animal model of psoriasis, probably thanks to its profound anti-inflammatory, antioxidant, antiangiogenic, and antiproliferative activities.

Shared Pathophysiology of Inflammatory Bowel Disease and Psoriasis: Unraveling the Connection

Psoriasis (PS) and inflammatory bowel disease (IBD) are immune-mediated chronic conditions that share pathophysiological processes, including immune system dysfunction, microbiome dysbiosis, and inflammatory pathways. These pathways result in increased turnover of epithelial cells and compromised barrier function. The assessment of the literature suggests that immunopathogenic mechanisms, such as tumor necrosis factor (TNF)-α signaling and IL-23/IL-17 axis dysregulation, are shared by PS and IBD. Clinical characteristics and diagnostic approaches overlap significantly, and advances in biomarker identification benefit both conditions. Current treatments, namely biologics that target TNF-α, IL-17, and IL-23, show promising results in decreasing inflammation and controlling symptoms. Precision medicine approaches are prioritized in prospective therapeutic procedures to tailor pharmaceuticals based on specific biomarkers, perhaps improving outcomes and minimizing side effects. This study thoroughly examines and evaluates the body of research on PS and IBD. Several papers were examined to compile data on clinical features, diagnosis, therapies, pathophysiology, epidemiology, and potential future therapeutic developments. The selection of articles was based on three methodological qualities: relevance and addition to the knowledge of IBD and PS. The retrieved data were combined to provide a coherent summary of the state of the knowledge and to spot new trends. The overview of the latest studies demonstrates that both PS and IBD share pathophysiological foundations and therapeutic approaches. With a spotlight on particular biomarkers, advances in precision medicine provide a promising path toward enhancing therapeutic effectiveness and minimizing side effects.

Shared Pathophysiology of Inflammatory Bowel Disease and Psoriasis: Unraveling the Connection

Inflammatory bowel disease (IBD) and psoriasis are both chronic autoimmune diseases with a unique set of characteristics. Interestingly, both conditions share considerable overlap in their pathophysiological mechanisms and immune dysregulation. Epidemiological studies validate the relationship by showing a greater prevalence of co-occurrence of the two disorders. At the genetic level, there is a confirmation of a link between shared susceptibility loci and DNA polymorphism, particularly interleukin-23 receptor (IL23R), interleukin-12 subunit beta (IL12B), tumor necrosis factor (ligand) superfamily member 15 (TNFSF15), and signal transducer and activator of transcription 3 (STAT3). In addition, epigenetic factors have a role in genetic predisposition in the development and progression through processes such as DNA methylation and histone modification adding another layer of genetic susceptibility. The relationship between psoriasis and IBD is emphasized by a comparable immunopathogenesis, which involves delicate relationships between the innate and adaptive immune responses. The primary interest is on the T-helper 17 (Th17) cell pathway and the cytokines interleukin-17 (IL-17), interleukin-23 (IL-23), and tumor necrosis factor-alpha (TNF-α). Consequently, both disorders exhibit chronic inflammation and tissue restructuring, resulting from similar cellular and molecular processes. The presence of overlapping pathophysiology highlights the significance of implementing integrated management strategies and employing multidisciplinary techniques for both diagnosis and therapy. Hence, understanding the mutual processes might facilitate the advancement of precise biologic treatments that aim at these commonly shared inflammatory pathways.

IL-17A inhibitors alleviate Psoriasis with concomitant restoration of intestinal/skin microbiota homeostasis and altered microbiota function

Background

Disturbed gut microbiota and associated metabolic dysfunction exist in Psoriasis. Despite the growing use of interleukin-17 inhibitor (anti-IL17) therapy, the effect of anti-IL17 on gut/skin microbiota function is not fully understood in patients with Psoriasis.

Objective

Therefore, we explored whether Psoriasis is associated with alterations in selected gut/skin microbiota in a study cohort, and a longitudinal cohort study to reveal the effects of IL-17A inhibitor treatment on gut microbiota in Psoriasis.

Methods

In a case-control study, 14 patients with Psoriasis and 10 age, sex and body mass index-matched Healthy Controls were recruited. Longitudinal mapping of the gut microbiome was performed using 16S rRNA gene sequencing. Mouse models were used to further study and validate the interrelationship between the skin microbiome and the gut microbiome in Psoriasis. PICRUST2 was applied to predict the function of the bacterial community.

Results

In Psoriasis patients, gut microbiota dysbiosis was present with increased heterogeneity: decreased Bacteroidota and increased Firmicutes as well as Actinobacteriota predominating in Psoriasis. Escherichia-Shigella enrichment was associated with reduction in serum levels of total bile acid and markers in Apoptotic pathways. After IL-17A inhibitor treatment in Psoriasis patients, longitudinal studies observed a trend toward a normal distribution of the gut microbiome and modulation of apoptosis-related metabolic pathways. Results from a mouse model showed dysregulation of the skin microbiota in Psoriasis characterized by Staphylococcus colonization.

Conclusion

The psoriatic gut/skin microbiota exhibits loss of community stability and pathogen enrichment. IL-17A inhibitors restore microbiota homeostasis and metabolic pathways, reduce pro-inflammatory cytokine expression, and alleviate symptoms in patients with Psoriasis.

Evidence for the gut-skin axis: Common genetic structures in inflammatory bowel disease and psoriasis

BACKGROUND

Inflammatory bowel disease (IBD) and psoriasis (Ps) are common immune-mediated diseases that exhibit clinical comorbidity, possibly due to a common genetic structure. However, the exact mechanism remains unknown.

METHODS

The study population consisted of IBD and Ps genome-wide association study (GWAS) data. Genetic correlations were first evaluated. Then, the overall evaluation employed LD score regression (LDSC), while the local assessment utilized heritability estimation from summary statistics (HESS). Causality assessment was conducted through two-sample Mendelian randomization (2SMR), and genetic overlap analysis utilized the conditional false discovery rate/conjunctional FDR (cond/conjFDR) method. Finally, LDSC applied to specifically expressed genes (LDSC-SEG) was performed at the tissue level. For IBD and Ps-specific expressed genes, genetic correlation, causality, shared genetics, and trait-specific associated tissues were methodically examined.

RESULTS

At the genomic level, both overall and local genetic correlations were found between IBD and Ps. MR analysis indicated a positive causal relationship between Ps and IBD. The conjFDR analysis with a threshold of < 0.01 identified 43 loci shared between IBD and Ps. Subsequent investigations into disease-associated tissues indicated a close association of IBD and Ps with whole blood, lung, spleen, and EBV-transformed lymphocytes.

CONCLUSION

The current research offers a novel perspective on the association between IBD and Ps. It contributes to an enhanced comprehension of the genetic structure and mechanisms of comorbidities in both diseases.

Inflammation and Psoriasis: A Comprehensive Review

Psoriasis is an immune-mediated disease with a strong genetic component that brings many challenges to sick individuals, such as chronic illness, and which has multiple associated comorbidities like cardiovascular disease, metabolic syndrome, inflammatory bowel disease, and psychological disorders. Understanding the interplay between the innate and adaptative immune system has led to the discovery of specific cytokine circuits (Tumor Necrosis Factor-alpha (TNF-α), IL-23, IL-17), which has allowed scientists to discover new biomarkers that can be used as predictors of treatment response and pave the way for personalized treatments. In this review, we describe the footprint psoriasis leaves on the skin and beyond, key pathophysiological mechanisms, current available therapeutic options, and drawbacks faced by existing therapies, and we anticipate potential future perspectives that may improve the quality of life of affected individuals.

Genetic causal relationship between gut microbiome and psoriatic arthritis: a bidirectional two-sample Mendelian randomization study

Background

Several observational studies have suggested a potential relationship between gut microbiome and psoriatic arthritis (PsA). However, the causality of this relationship still remains unclear. We aim to explore if the specific gut microbiome is causally associated with PsA at the genetic level and offer valuable insights into the etiology of PsA.

Methods

In this study, we employed a bidirectional two-sample Mendelian randomization (MR) analysis to investigate the causal effects of the gut microbiome on PsA. Publicly accessible genome-wide association study summary data of gut microbiome were obtained from the MiBioGen consortium (n = 14,306), while the summary statistics of psoriatic arthropathies were sourced from the FinnGen consortium R8 release data (2,776 cases and 221,323 controls). The primary analytical method employed was inverse variance weighted (IVW), complemented by supplementary methods including MR-Egger, weighted median, weighted mode, maximum likelihood, MR-PRESSO, and cML-MA. Reverse MR analysis was performed on the bacteria that were found to be causally associated with PsA in forward MR analysis. Cochran's IVW Q statistic was utilized to assess the heterogeneity of instrumental variables among the selected single nucleotide polymorphisms.

Results

IVW estimates revealed that Ruminococcaceae_UCG-002 (odds ratio (OR) = 0.792, 95% confidence interval (CI), 0.643-0.977, p = 0.029) exhibited a protective effect on PsA. Conversely, Blautia (OR = 1.362, 95% CI, 1.008-1.842, p = 0.044), Eubacterium_fissicatena_group (OR = 1.28, 95% CI, 1.075-1.524, p = 0.006), and Methanobrevibacter (OR = 1.31, 95% CI, 1.059-1.621, p = 0.013) showed a positive correlation with the risk of PsA. No significant heterogeneity, horizontal pleiotropy, or outliers were observed, and the results of the MR analysis remained unaffected by any single nucleotide polymorphisms. According to the results of reverse MR analysis, no significant causal effect of PsA was found on gut microbiome.

Conclusion

This study establishes for the first time a causal relationship between the gut microbiome and PsA, providing potential valuable strategies for the prevention and treatment of PsA. Further randomized controlled trials are urgently warranted to support the targeted protective mechanisms of probiotics on PsA.

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.

Skin microbiota signature distinguishes IBD patients and reflects skin adverse events during anti-TNF therapy

Crohn's disease (CD) and ulcerative colitis (UC) are two forms of inflammatory bowel disease (IBD), where the role of gut but not skin dysbiosis is well recognized. Inhibitors of TNF have been successful in IBD treatment, but up to a quarter of patients suffer from unpredictable skin adverse events (SkAE). For this purpose, we analyzed temporal dynamics of skin microbiota and serum markers of inflammation and epithelial barrier integrity during anti-TNF therapy and SkAE manifestation in IBD patients. We observed that the skin microbiota signature of IBD patients differs markedly from healthy subjects. In particular, the skin microbiota of CD patients differs significantly from that of UC patients and healthy subjects, mainly in the retroauricular crease. In addition, we showed that anti-TNF-related SkAE are associated with specific shifts in skin microbiota profile and with a decrease in serum levels of L-FABP and I-FABP in IBD patients. For the first time, we showed that shifts in microbial composition in IBD patients are not limited to the gut and that skin microbiota and serum markers of the epithelium barrier may be suitable markers of SkAE during anti-TNF therapy.

New onset severe ulcerative colitis following Ixekizumab therapy

Ixekizumab is one of the three biologic agents including Secukinumab and Brodalumab that targets the Interleukin-17 (IL-17) pathway to reduce inflammation in psoriasis and ankylosing spondylitis. In this report we present the case of 42-year-old woman, who was diagnosed with psoriasis and psoriatic arthritis. One week after first administration of Ixekizumab, she developed diffuse abdominal pain, bloody diarrhea (7-8 stools/day) and fever. Following imaging (colonoscopy, computed tomography) and laboratory investigations, she was diagnosed with acute severe ulcerative colitis complicated with toxic megacolon. The medical treatment (first corticotherapy, then infliximab) has failed and the patient needed emergency colectomy. Based on the immunological mechanisms and the observation from other studies, Ixekizumab should be considered an etiology for new-onset inflammatory bowel disease.

The Treatment with Interleukin 17 Inhibitors and Immune-Mediated Inflammatory Diseases

IL-17 inhibitors (IL-17i) are medicines used to treat dermatological and rheumatic diseases They belong to a class of medicines called biological disease-modifying anti-rheumatic drugs (bDMARDs). This class of drugs has had a major impact on the therapy of autoimmune diseases, being much safer and more effective than treatment with small molecules. At the same time, they have highly beneficial effects on skin and joint changes, and their efficacy has been extensively monitored and demonstrated in numerous clinical trials. More and more such drugs are still being discovered today to ensure the best possible treatment of these patients, but more frequently and relatively constantly three agents are used. Two of them (Secukinumab and Ixekizumab) inhibit IL-17A directly, and the third, Brodamulab, inhibits the IL-17A receptor. Although they are extremely effective in the treatment of these diseases, sometimes their administration has been associated with paradoxical effects, i.e., there is an exacerbation of the inflammatory process. Tough, clinical trials of IL-17i have described cases of exacerbation or even onset of inflammatory bowel disease (IBD), such as Crohn's disease and ulcerative colitis, after administration of these drugs in patients previously diagnosed with psoriasis (PS), psoriatic arthritis (PsA), or ankylosing spondylitis (AS). The pathophysiological mechanism of action is not well understood at present. One explanation would be that this hyperreactive inflammatory process would be triggered by Interferon 1 derived from dendritic plasma cells. Even though there are many reports in the recent literature about the role of IL17i in the onset of IBD, conclusions of studies do not converge. Some of them show an increased incidence of IBD in patients treated with IL17i, while some others affirm their safety of them. In the near future we will surely have more data emerging from ongoing meta-analyses regarding safety of use IL17i in patients who are at risk of developing IBD. Clinical and paraclinical evaluation (inflammatory intestinal markers) are carefully advised before recommending treatment with IL-17i and after initiation of treatment, and prospective surveillance by clinical and biomarkers of patients treated with IL-17i is absolutely essential to capture the onset of IBD.

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.

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.

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

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

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.

Skin inflammation activates intestinal stromal fibroblasts and promotes colitis

Inflammatory disorders of the skin are frequently associated with inflammatory bowel diseases (IBDs). To explore mechanisms by which these organs communicate, we performed single-cell RNA-Seq analysis on fibroblasts from humans and mice with IBD. This analysis revealed that intestinal inflammation promoted differentiation of a subset of intestinal stromal fibroblasts into preadipocytes with innate antimicrobial host defense activity. Furthermore, this process of reactive adipogenesis was exacerbated if mouse skin was inflamed as a result of skin wounding or infection. Since hyaluronan (HA) catabolism is activated during skin injury and fibroblast-to-adipocyte differentiation is dependent on HA, we tested the hypothesis that HA fragments could alter colon fibroblast function by targeted expression of human hyaluronidase-1 in basal keratinocytes from mouse skin. Hyaluronidase expression in the skin activated intestinal stromal fibroblasts, altered the fecal microbiome, and promoted excessive reactive adipogenesis and increased inflammation in the colon after challenge with dextran sodium sulfate. The response to digested HA was dependent on expression of TLR4 by preadipocytes. Collectively, these results suggest that the association between skin inflammation and IBD may be due to recognition by mesenchymal fibroblasts in the colon of HA released during inflammation of the skin.

The Temporal Relationships and Associations between Cutaneous Manifestations and Inflammatory Bowel Disease: A Nationwide Population-Based Cohort Study

The temporal relationships between inflammatory bowel disease (IBD)-associated cutaneous manifestations and IBD remain uncertain, with existing evidence mostly from separate cross-sectional studies. We sought to determine the risks of IBD-related dermatologic diseases before and after the diagnosis of IBD. We identified 2847 cases of IBD and 14,235 matched controls from the Taiwan National Health Insurance Research Database between 2003 and 2014. The risks of cutaneous manifestations before and after the diagnosis of IBD were estimated with multivariable-adjusted analyses. At diagnosis, IBD was associated with atopic dermatitis (odds ratio (OR) = 1.61; 95% confidence interval (CI), 1.14-2.28), erythema nodosum (OR = 7.44; 95%CI, 3.75-14.77), aphthous stomatitis (OR = 2.01; 95%CI, 1.72-2.35), polyarteritis nodosa (OR = 5.67; 95%CI, 2.69-11.98), rosacea (OR = 1.67, 95%CI = 1.19-2.35), and cutaneous T cell lymphoma (OR = 21.27; 95%CI, 2.37-191.00). IBD was associated with the subsequent development of pyoderma gangrenosum (hazard ratio (HR) = 17.79; 95%CI, 6.35-49.86), erythema nodosum (HR = 6.54; 95%CI, 2.83-15.13), polyarteritis nodosa (HR = 2.69; 95%CI, 1.05-6.90), hidradenitis suppurativa (HR = 2.48; 95%CI, 1.03-5.97), psoriasis (HR = 2.19; 95%CI, 1.27-3.79), rosacea (HR = 1.92; 95%CI, 1.39-2.65), and aphthous stomatitis (HR = 1.45; 95%CI, 1.22-1.72). This study clarified the associations and temporal relationships between cutaneous manifestations and IBD, highlighting the need for interdisciplinary care in the patient with specific dermatologic diseases presenting with abdominal symptoms, or the IBD patients with cutaneous lesions.

Therapeutic Implications of Diet in Inflammatory Bowel Disease and Related Immune-Mediated Inflammatory Diseases

Despite being a focal issue to patients, the effect of diet on adult inflammatory bowel disease (IBD) remains underexplored with limited guidance. While promising clinical trials are currently underway, there is a need for further evidence-based recommendations. As such, we summarize the current evidence on various diets used in the treatment of IBD and also explore the potential applications of dietary data from related immune-mediated inflammatory diseases (IMIDs), such as rheumatoid arthritis and psoriasis, to provide additional information to inform IBD providers. To date, there have been multiple diets investigated as adjunctive therapy in IBD, but many associated studies are small, non-randomized, and not controlled. Mediterranean, vegetarian/vegan, and reduced-calorie/fasting diets have been studied and have shown some positive results in other IMIDs, which may suggest potential applicability to those with IBD, but larger, well-designed clinical trials are needed for further guidance. Gluten-free and low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP)diets do not appear to have an impact on IBD disease activity, but low FODMAP may potentially be helpful for those with concurrent functional gastrointestinal symptoms. Specific carbohydrate diets have been mainly assessed in children but show some potential in small adult studies.

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.

Crohn's disease exacerbated by IL-17 inhibitors in patients with psoriasis: a case report

BACKGROUND

Previous studied revealed that psoriasis and Inflammatory bowel disease (IBD) have highly overlapping epidemiological characteristics, genetic susceptibility loci, disease risk factors, immune mechanisms, and comorbidities. More and more biologics have been used to treat psoriasis and IBD. Interleukin (IL)-17 inhibitors played an important role in the treatment of psoriasis, but induced and aggravated inflammatory bowel disease in some patients. IL-23 inhibitors have shown to be effective to both psoriasis and CD.

CASE PRESENTATION

Forty-one year old Chinese male patient who came to the hospital for psoriasis, developed severe gastrointestinal symptoms after using an IL-17 inhibitor, and was diagnosed with Crohn's disease (CD). The patient eventually used an IL-23 inhibitor to relieve both psoriasis and CD.

CONCLUSION

IBD patients and psoriasis patients have increased probability of suffering from the other disease. The case that patients had suffered from psoriasis and CD before the use of IL-17 inhibitor is quite rare. This case suggests that physicians need to be careful when treating patients with psoriasis and CD with biologics, and it is necessary to evaluate the gastrointestinal tract.

The Diagnostic-Therapeutic Care Pathway in Psoriasis: Towards ISO 9001:2015 Certification

Background and objectives: Psoriasis (Pso) is a common skin condition characterized by a strong psychosocial impact, and is nowadays accepted as a systemic immune-mediated inflammatory disease. Diagnostic–Therapeutic Care Pathways (DTCPs) represent a predefined sequence of diagnostic, therapeutic, and assistance activities that integrate the participation of several specialists to obtain, for each patient, the correct diagnosis and thus the most appropriate therapy. A DTCP was validated in our dermatology clinic (AOU Maggiore della Carità, Novara, Italy). The validation process included the detailed elaboration of a protocol of diagnosis, staging of care, therapies, and follow-up of the patient with Pso. The formalization and adaptation of our DTCP resulted in ISO 9001: 2015 certification in May 2019. Materials and methods: This process involved several stages, including analysis of context and the identification of (i) targets, (ii) indicators, and (iii) service providers. The evaluation was based on a cohort of over 200 patients affected by moderate to severe Pso, who were treated and followed-up at our institution from September 2017 to April 2019. Results: The ISO 9001:2015 quality certification process allowed us to identify our weaknesses, i.e., the long waiting times for the first visit and the reduced physician–patient ratio, but also our strengths, such as the commitment to clinical research, effective collaboration with other specialists, the efficient use of technological and human resources, and attention to ensuring patient follow-up. Conclusions: In qualifying for and achieving the ISO Quality Management System (QMS) certification we were heartened to realize that our basic methodology and approach were fit for purpose. The implementation of the ISO QMS helped us to reorganize our priorities by placing the patient at the center of the process and raising awareness that Pso is not just a skin disease.

Correlation between Antibodies to Bacterial Lipopolysaccharides and Barrier Proteins in Sera Positive for ASCA and ANCA

Individuals with intestinal barrier dysfunction are more prone to autoimmunity. Lipopolysaccharides (LPS) from gut bacteria have been shown to play a role in systemic inflammation, leading to the opening of the gut and blood-brain barrier (BBB). This study aims to measure antibodies against LPS and barrier proteins in samples positive for anti-Saccharomyces cerevisiae antibodies (ASCA) and anti-neutrophil cytoplasmic antibodies (ANCA) and compare them with these same antibodies in controls to determine whether a correlation between LPS and barrier proteins could be found. We obtained 94 ASCA- and 94 ANCA-positive blood samples, as well as 188 blood samples from healthy controls. Samples were assessed for antibodies to LPS, zonulin+occludin, S100B, and aquaporin-4 (AQP4). Results show significant elevation in antibodies in about 30% of ASCA- and ANCA-positive sera and demonstrate positive linear relationships between these antibodies. The findings suggest that individuals positive for ASCA and ANCA have increased odds of developing intestinal and BBB permeability compared to healthy subjects. The levels of LPS antibodies in both ASCA- and ANCA-positive and negative specimens showed from low and moderate to high correlation with antibodies to barrier proteins. This study shows that LPS, by damaging the gut and BBBs, contribute to the extra-intestinal manifestation of IBD. We conclude that IBD patients should be screened for LPS antibodies in an effort to detect or prevent possible barrier damage at the earliest stage possible to abrogate disease symptoms in IBS and associated disorders.

Asymptomatic Crohn's disease identified in a patient being treated with secukinumab: A case report

IL-17 antagonism is among the most potent treatments for psoriasis. Generally safe, new onset and exacerbations of inflammatory bowel disease may occur in association with IL-17 therapy. We describe a patient with long-standing history of psoriasis and psoriatic arthritis in whom asymptomatic Crohn’s disease was identified during treatment with secukinumab. The patient underwent an elective colonoscopy for colorectal cancer screening which revealed inflammation and multiple ulcers in the terminal ileum suggestive of Crohn’s disease. While the patient did not have any gastrointestinal symptoms, he was diagnosed as having asymptomatic Crohn’s disease. Given the association of inflammatory bowel disease with secukinumab treatment, secukinumab was discontinued. Although in this patient, Crohn’s disease was identified during treatment with secukinumab, a direct causal relationship cannot be assumed. Medications that are effective for both psoriasis and inflammatory bowel disease may be a good choice in patients with psoriasis who have comorbid Crohn’s disease or develop inflammatory bowel disease during treatment with another biologic.

Interleukin-22 and Its Correlation with Disease Activity in Plaque Psoriasis

Psoriasis is a chronic debilitating skin disease with an estimated prevalence reaching 2% of the worldwide population. Psoriatic disease is driven by a network of complicated reciprocal interactions among innate and adaptive mechanisms of immune system with structural components of the skin. Interleukin (IL)-22 mediates keratinocyte proliferation and epidermal hyperplasia, inhibits terminal differentiation of keratinocytes, and induces the production of antimicrobial proteins. The aim of this study was the assessment of IL-22 levels and its correlation with disease activity in plaque psoriasis. The study group included 64 patients with mild, moderate and severe psoriasis. Control group was composed of 24 sex- and age-matched healthy volunteers. IL-22 concentration was assessed in supernatants of T-cell cultures as well as in the plasma of study and control group with the use of ELISA method. Statistical analysis showed that concentration of IL-22 in cultures exposed to staphylococcal enterotoxin B was significantly higher than in control samples (p = 0.005) and cultures treated with IL-12 (p = 0.005). Patients with psoriasis presented significantly higher concentrations of IL-22 than healthy individuals (p = 0.0000001). In conclusion, IL-22 may collaborate with other soluble factors and cells together forming inflammatory circuits that otherwise exist as constitutive or inducible pathways in normal skin and become pathologically amplificated in psoriasis. Targeting IL-22 may be promising as a potential therapeutic for plaque psoriasis.

Incidence rates of inflammatory bowel disease in patients with psoriasis, psoriatic arthritis and ankylosing spondylitis treated with secukinumab: a retrospective analysis of pooled data from 21 clinical trials

OBJECTIVES

Here, we present the reported incidence rates of inflammatory bowel disease (IBD) in patients receiving treatment with secukinumab for psoriasis (PsO), psoriatic arthritis (PsA) or ankylosing spondylitis (AS), in a pooled analysis of 21 clinical trials.

METHODS

Data from all patients who had received at least one dose of secukinumab were included. Safety analyses were conducted to evaluate cumulative IBD rates as well as per-year rates, by indication. Crohn's disease (CD), ulcerative colitis (UC) and IBD unclassified (IBDU) events were analysed using exposure-adjusted incidence rates (patient incidence rates per 100 patient-years (PY)).

RESULTS

A total of 7355 patients with a cumulative exposure of 16 226.9 PY were included in the pooled analysis. Among 5181 patients with PsO, there were 14 cases of UC, 5 cases of CD and 1 case of IBDU, with exposure adjusted incidence rates (EAIRs) of 0.13, 0.05 and 0.01, respectively. Of these 20 cases, 14 were new-onset. In 1380 patients with PsA, there were 3 cases of UC, 3 cases of CD and 2 cases of IBDU (EAIRs 0.08, 0.08 and 0.05); 7 of these represented new-onset cases. Among 794 patients with AS, there were 4 cases of UC, 8 cases of CD and 1 case of IBDU (EAIRs 0.2, 0.4 and 0.1); 9 were new-onset cases. In the per year analysis, the EAIRs for each indication did not increase over time with secukinumab treatment.

CONCLUSIONS

In this pooled secukinumab safety analysis of 7355 patients across 21 clinical trials, cases of IBD events (including CD, UC and IBDU) were uncommon.

Psoriasis Features in Patients with Inflammatory Bowel Disease

BACKGROUND:

Psoriasis and inflammatory bowel diseases (IBD) share common pathways based on immune dysregulation with an important role of tumour necrosis factor-α and Th17 cells, as well as the genetic background. Several studies showed an increased prevalence of psoriasis in IBD patients. However, data regarding psoriasis features in IBD patients are still lacking.

AIM:

We aimed to conduct an observational study to assess psoriasis clinical features and its severity in a group of patients with IBD.

METHODS:

Dermatological assessment was performed consecutively in 200 IBD patients (123 with CD and 77 with UC) attending the IBD Care Centre of Gastroenterology at the University of Naples Federico II from 2015 to 2016.

RESULTS:

A group of 32 from 200 IBD patients (16%) had a familiar history positive for psoriasis, whereas, medical history and dermatologic examination revealed that 18 (9%) IBD patients were affected by psoriasis: 11 out of these 18 subjects (61.2%) had CD, and 7 had UC (38.2%); no significant differences were found between CD and UC groups. Concerning psoriasis severity, the mean psoriasis area severity index score was 3.7.

CONCLUSION:

This one-year retrospective study showed that psoriasis and IBD both require the use of immunosuppressive drugs so; we can count on a better treatment outcome for both diseases.

Crucial Role of Microbiota in Experimental Psoriasis Revealed by a Gnotobiotic Mouse Model

Psoriatic patients have altered microbiota, both in the intestine and on the skin. It is not clear, however, whether this is a cause or consequence of the disease. In this study, using an experimental mouse model of psoriasis induced by imiquimod (IMQ), we show that oral treatment with a broad spectrum of antibiotics (MIX) or metronidazole (MET) alone mitigates the severity of skin inflammation through downregulation of Th17 immune response in conventional mice. Since some antibiotics, including MET, can influence immune system reactivity, we also evaluated the effect of MIX in the same model under germ-free (GF) conditions. GF mice treated with MET did not show milder signs of imiquimod-induced skin inflammation (IISI) which supports the conclusion that the therapeutic effect is mediated by changes in microbiota composition. Moreover, compared to controls, mice treated with MIX had a significantly higher abundance of the genus Lactobacillus in the intestine and on the skin. Mice treated with MET had a significantly higher abundance of the genera Bifidobacterium and Enterococcus both on the skin and in the intestine and of Parabacteroides distasonis in the intestine. Additionally, GF mice and mice monocolonized with either Lactobacillus plantarum or segmented filamentous bacteria (SFB) were more resistant to IISI than conventional mice. Interestingly, compared to GF mice, IMQ induced a higher degree of systemic Th17 activation in mice monocolonized with SFB but not with L. plantarum. The present findings provide evidence that intestinal and skin microbiota directly regulates IISI and emphasizes the importance of microbiota in the pathogenesis of psoriasis.

Digestive system in psoriasis: an update

Psoriasis is a chronic inflammatory immune-mediated disorder associated and often coexisting with many other immune-related clinical conditions including those affecting the gastrointestinal tract. Data obtained from the reviewed literature suggest an association between psoriasis and pathologies of the oral cavity, both psoriasis-specific lesions, as well as non-specific, such as geographic tongue or fissured tongue. These findings show the importance of thorough examination of oral mucosa in psoriatic patients. Inflammatory bowel diseases (IBD) are also linked with psoriasis. Crohn’s disease and ulcerative colitis share a common genetic background, inflammatory pathways and have an evident iatrogenic anti-TNF treatment link, necessitating dermatological or gastroenterological care in patients with IBD or psoriasis, respectively, as well as treatment adjusted to manifestations. The presence of celiac disease-specific antibodies in psoriatic patients and their correlation with the severity of the disease show the association between these disorders. The linking pathogenesis comprises vitamin D deficiency, immune pathway, genetic background and increase in the intestinal permeability, which suggests a potential benefit from gluten-free diet among psoriatic patients. The link between psoriasis and non-alcoholic fatty liver disease implies screening patients for components of metabolic syndrome and lifestyle changes necessity. Some studies indicate increased prevalence of cancer in patients with psoriasis, probably due to negative influence of skin lesion impact on lifestyle rather than the role of psoriasis in carcinogenesis. However, there are no sufficient data to exclude such an oncogenic hit, which is yet to be confirmed. Therefore, all psoriasis-associated comorbidities establish the importance of a multidisciplinary approach in the treatment of these patients.