Is Psoriasis Treatment a Risk Factor for Inflammatory Bowel Disease?

Paradoxical Reactions to Anti-TNFα and Anti-IL-17 Treatment in Psoriasis Patients: Are Skin and/or Gut Microbiota Involved?

Psoriasis is a chronic, immune-mediated, inflammatory disease primarily affecting the skin. It is currently coming to light that patients with psoriasis have disrupted intestinal barrier and often suffer from comorbidities associated with the gastrointestinal tract. Moreover, there is growing evidence of both cutaneous and intestinal paradoxical reactions during biologic treatment in patients with psoriasis. This review focuses on barrier defects and changes in immune responses in patients with psoriasis, which play an important role in the development of the disease but are also influenced by modern biological treatments targeting IL-17 and TNFα cytokines. Here, we highlight the relationship between the gut-skin axis, microbiota, psoriasis treatment, and the incidence of paradoxical reactions, such as inflammatory bowel disease in patients with psoriasis. A better understanding of the interconnection of these mechanisms could lead to a more personalized therapy and lower the incidence of treatment side effects, thereby improving the quality of life of the affected patients.

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 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.

Causal Biological Network Model for Inflammasome Signaling Applied for Interpreting Transcriptomic Changes in Various Inflammatory States

Virtually any stressor that alters the cellular homeostatic state may result in an inflammatory response. As a critical component of innate immunity, inflammasomes play a prominent role in the inflammatory response. The information on inflammasome biology is rapidly growing, thus creating the need for structuring it into a model that can help visualize and enhance the understanding of underlying biological processes. Causal biological network (CBN) models provide predictive power for novel disease mechanisms and treatment outcomes. We assembled the available literature information on inflammasome activation into the CBN model and scored it with publicly available transcriptomic datasets that address viral infection of the lungs, osteo- and rheumatoid arthritis, psoriasis, and aging. The scoring inferred pathway activation leading to NLRP3 inflammasome activation in these diverse conditions, demonstrating that the CBN model provides a platform for interpreting transcriptomic data in the context of inflammasome activation.

Very low-calorie ketogenic diet (VLCKD) in patients with psoriasis and obesity: an update for dermatologists and nutritionists

Psoriasis is a chronic skin immune-mediated disease with systemic pro-inflammatory activation; both genetic and lifestyles factors contribute to its pathogenesis and severity. In this context, nutrition plays a significant role, per se, in psoriasis' pathogenesis. Obesity is another important risk factor for psoriasis, and weight reduction may improve psoriasis' clinical severity. The excess body weight, particularly visceral fat mass, can affect both drug's pharmacokinetics and pharmacodynamics. Therefore, psoriasis and obesity share a certain degree of synergy, and the chronic inflammatory state represents the basis of this vicious cycle. Evidence reported that nutrition has different impact on the clinical severity of psoriasis, though some specific diets have been more investigated in clinical studies compared to others. Diets with systemic anti-inflammatory properties seem to have a higher effect on improving the clinical severity of psoriasis. Of interest, very-low-calorie ketogenic diet (VLCKD), through the production of ketone bodies, has been associated with both a significant reduction of body weight and inflammatory state. VLCKD leading to both weight loss and reduction of systemic inflammation may decrease the exacerbation of the clinical manifestations or even it may block the trigger of psoriatic disease. This dietary pattern could represent a potential first-line treatment in psoriatic patients with obesity. The review aims to summarize the current evidence regarding VLCKD and psoriasis with specific reference to antioxidant and anti-inflammatory effects of this dietary pattern.