Interaction between microbiome and host genetics in psoriatic arthritis

Early psoriatic arthritis: clinical and therapeutic challenges

INTRODUCTION

Psoriatic arthritis (PsA) is a chronic immunoinflammatory disease of the enthesis and adjacent synovium, skin, and nail, which early diagnosis may be crucial for starting a prompt therapeutic intervention. Theoretically, early treatment offers the advantage of acting on the reduction of the articular damage progression since initial phases of the disease.

AREAS COVERED

This review explores the challenges of clinical-diagnostic aspects and the underlying pathophysiology of early PsA phases, as well as the evidence evaluating the impact of early intervention on disease outcomes.

EXPERT OPINION

Main instruments for early PsA diagnosis include recognizing synovial-entheseal inflammatory signs at onset, improving screening PsA high-risk subjects, and increasing disease knowledge of physicians and patients with psoriasis or familial history. PsA continues to significantly impact on the Quality of Life of patients affected by the disease, making necessary to deeply study clinical manifestations, risk factors, and underlying immunoinflammatory mechanisms, as well as to identify biomarkers for early identification. Additionally, it remains a need to increase more evidence on understanding how early treatment of PsA and of psoriasis might influence the course of the disease.

Dysbiosis of the Gut Microbiota in Patients with Psoriatic Arthritis is Closely Related to Lymphocyte Subsets and Cytokines

The purpose of this research was to characterize the microbiota of patients with psoriatic arthritis (PsA) and to compare the relationship between the microbiota and peripheral lymphocyte subsets and cytokines. We collected stool samples from 13 PsA patients and 26 sex- and age-matched healthy controls (HCs) and researched the gut microbiota by sequencing the V3-V4 variable region of the bacterial 16S rRNA gene with the Illumina Miseq PE300 system. Flow cytometry was used to assess the peripheral lymphocyte subsets in these participants. Record measures of disease activity such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Alpha and beta diversity were assessed using results from QIIME2. Panel demonstrated the average relative abundance of the different genera in PsA and HCs. Correlation between clinical parameters and the relative abundance of the genus in samples was assessed by the Pearson correlation analysis using R (version 4.0.1). Compared with HC, the abundance of gut microbiota (Chao 1 and ACE) decreased in patients with PsA, and the diversity of bacteria (Shannon and Simpson indices) also decreased in PsA (Fig. 1a). β Diversity analysis indicated differences in microbial communities between PsA and HC (Fig. 1b, r = 0.039, p = 0.264, ANOSIM). Furthermore, 18 bacterial groups were significantly different at the genus level in PsA compared to HCs (p < 0.05) (Fig. 2).In the phylum and genus, lymphocyte subsets and cytokines are associated with the microbiota. The gut microbiota of patients with PsA differs from HC, which was closely related to lymphocyte subsets.

Recent developments for new investigational JAK inhibitors in psoriatic arthritis

INTRODUCTION

Psoriatic arthritis (PsA) is a chronic inflammatory disease affecting about one-third of subjects with psoriasis. Several treatment modalities targeting Janus Kinase pathways and intracellular inflammatory cascade are now available and under clinical investigation to treat this disease.

AREAS COVERED

This review describes ongoing and recently completed phase 2 and 3 Randomized Clinical Trials (RCTs) evaluating the efficacy and safety of approved JAK (Tofacitinib and Upadacitinib) and investigational JAK inhibitors (JAK1 inhibitors: Filgotinib and Ivarmacitinib (SHR0302); TYK2 inhibitors: Brepocitinib (PF-06700841) Deucravacitinib (BMS-986165), and NDI-034858) in PsA through February 2023.

EXPERT OPINION

Current standard of care has significantly improved the quality of life in PsA. Recently approved JAK inhibitors for PsA have addressed many of the unmet needs of PsA, particularly of those with severe phenotypes. Preliminary results from several RCTs have reported good and fast efficacy and an acceptable safety profile of investigational JAK inhibitors in PsA. Additional clinical trials and long-term outcome data on these agents are necessary for increasing available therapeutic options for PsA.

How Has Molecular Biology Enhanced Our Undertaking of axSpA and Its Management

PURPOSE

This review aims at investigating pathophysiological mechanisms in spondyloarthritis (SpA). Analysis of genetic factors, immunological pathways, and abnormalities of bone metabolism lay the foundations for a better understanding of development of the axial clinical manifestations in patients, allowing physician to choose the most appropriate therapeutic strategy in a more targeted manner.

RECENT FINDINGS

In addition to the contribution of MHC system, findings emerged about the role of non-HLA genes (as ERAP1 and 2, whose inhibition could represent a new therapeutic approach) and of epigenetic mechanisms that regulate the expression of genes involved in SpA pathogenesis. Increasing evidence of bone metabolism abnormalities secondary to the activation of immunological pathways suggests the development of various bone anomalies that are present in axSpA patients. SpA are a group of inflammatory diseases with a multifactorial origin, whose pathogenesis is linked to the genetic predisposition, the action of environmental risk factors, and the activation of immune response. It is now well known how bone metabolism leads to long-term structural damage via increased bone turnover, bone loss and osteoporosis, osteitis, erosions, osteosclerosis, and osteoproliferation. These effects can exist in the same patient over time or even simultaneously. Evidence suggests a cross relationship among innate immunity, autoimmunity, and bone remodeling in SpA, making treatment approach a challenge for rheumatologists. Specifically, treatment targets are consistently increasing as new drugs are upcoming. Both biological and targeted synthetic drugs are promising in terms of their efficacy and safety profile in patients affected by SpA.

The Yin-Yang Pharmacomicrobiomics on Treatment Response in Inflammatory Arthritides: A Narrative Review

(1) Background: Gut microbiota (GM) is the set of microorganisms inhabiting the gastroenteric tract that seems to have a role in the pathogenesis of rheumatic diseases. Recently, many authors proved that GM may influence pharmacodynamics and pharmacokinetics of several drugs with complex interactions that are studied by the growing field of pharmacomicrobiomics. The aim of this review is to highlight current evidence on pharmacomicrobiomics applied to the main treatments of Rheumatoid Arthritis and Spondyloarthritis in order to maximize therapeutic success, in the framework of Personalized Medicine. (2) Methods: We performed a narrative review concerning pharmacomicrobiomics in inflammatory arthritides. We evaluated the influence of gut microbiota on treatment response of conventional Disease Modifying Anti-Rheumatic drugs (cDMARDs) (Methotrexate and Leflunomide) and biological Disease Modifying Anti-Rheumatic drugs (bDMARDs) (Tumor necrosis factor inhibitors, Interleukin-17 inhibitors, Interleukin 12/23 inhibitors, Abatacept, Janus Kinase inhibitors and Rituximab). (3) Results: We found a great amount of studies concerning Methotrexate and Tumor Necrosis Inhibitors (TNFi). Conversely, fewer data were available about Interleukin-17 inhibitors (IL-17i) and Interleukin 12/23 inhibitors (IL-12/23i), while none was identified for Janus Kinase Inhibitors (JAKi), Tocilizumab, Abatacept and Rituximab. We observed that microbiota and drugs are influenced in a mutual and reciprocal way. Indeed, microbiota seems to influence therapeutic response and efficacy, whereas in the other hand, drugs may restore healthy microbiota. (4) Conclusions: Future improvement in pharmacomicrobiomics could help to detect an effective biomarker able to guide treatment choice and optimize management of inflammatory arthritides.

Altered Fecal Metabolomics and Potential Biomarkers of Psoriatic Arthritis Differing From Rheumatoid Arthritis

Psoriatic arthritis (PsA) is a chronic inflammatory joint disease, and the diagnosis is quite difficult due to the unavailability of reliable clinical markers. This study aimed to investigate the fecal metabolites in PsA by comparison with rheumatoid arthritis (RA), and to identify potential diagnostic biomarkers for PsA. The metabolic profiles of the fecal samples from 27 PsA and 29 RA patients and also 36 healthy controls (HCs) were performed on ultra-high-performance liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). And differentially altered metabolites were screened and assessed using multivariate analysis for exploring the potential biomarkers of PsA. The results showed that 154 fecal metabolites were significantly altered in PsA patients when compared with HCs, and 45 metabolites were different when compared with RA patients. A total of 14 common differential metabolites could be defined as candidate biomarkers. Furthermore, a support vector machines (SVM) model was performed to distinguish PsA from RA patients and HCs, and 5 fecal metabolites, namely, α/β-turmerone, glycerol 1-hexadecanoate, dihydrosphingosine, pantothenic acid and glutamine, were determined as biomarkers for PsA. Through the metabolic pathways analysis, we found that the abnormality of amino acid metabolism, bile acid metabolism and lipid metabolism might contribute to the occurrence and development of PsA. In summary, our research provided ideas for the early diagnosis and treatment of PsA by identifying fecal biomarkers and analyzing metabolic pathways.

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

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

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

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

Genetics, Epigenetics, and Gender Impact in Axial-Spondyloarthritis Susceptibility: An Update on Genetic Polymorphisms and Their Sex Related Associations

Spondyloarthritis (SpA) is a group of chronic inflammatory rheumatic disease that can be divided into predominantly axial or predominantly peripheral involvement, with or without associated psoriasis, inflammatory bowel disease or previous infection. Axial SpA (axSpA) encompasses ankylosing spondylitis (AS) with radiological sacroiliitis, and a type without radiographic sacroiliitis, called “non-radiographic axial SpA” (nr-axSpA). Males and females show large differences in their susceptibility to SpA, such as distinctions in clinical patterns, phenotypes and in therapeutical response, particularly to TNF inhibitors (TNFi). Several studies indicate that AS women have doubled risk to failure TNFi compared with males. This diversity in drugs’ efficacy among women and men may be caused by differences in the balance of sex hormones and in gene-specific expression likely triggered by X-chromosome instability and gene-specific epigenetic modifications. Evidence reported that polymorphisms in microRNAs on X- and other chromosomes, such as miR-146a, miR-155, miR-125a-5p, miR-151a-3p and miR-22-3p, miR-199a-5p could be involved in the different clinical presentation of SpA, as well as disease activity. In addition, association with non−response to TNFi treatment and presence of IRAK3 and CHUCK genes in SpA patients was recently detected. Finally, polymorphisms in genes involved in IL-23/IL-17 pathway, such as in drug pharmacodynamics and pharmacokinetics may have a role in response to TNFi, IL17i, and IL23i. A major understanding of genomic variability could help in the development of new therapeutic targets or in taking advantages of different mechanisms of action of biological drugs. Moving from the multifactorial etiology of disease, the present review aims at evaluating genetic and epigenetic factors and their relationship with sex and bDMARDs response, helping to investigate the different expression among males and females of genes on X- and other chromosomes, as well as mi-RNA, to highlight relationships between sex and occurrence of specific phenotypes and symptoms of the disease. Moreover, the role of the epigenetic modification in relation to immune-regulatory mechanisms will be evaluated.

The burden of depressive disorders in musculoskeletal diseases: is there an association between mood and inflammation?

IMPORTANCE

Evidence emerged concerning how inflammatory arthritis and mood disorders can often occur in the same patient and show a similar clinical pattern. An overview of the rheumatological and psychiatric aspects of these diseases can certainly be useful for the improvement of patients' clinical and therapeutic management.

OBJECTIVE

The aim of this narrative review was to summarize existing literature about common pathogenetic and clinical aspects as a means of improving management and therapeutic approach in patients affected by rheumatoid arthritis, psoriatic arthritis and spondyloarthritis. Outcomes such as disease activity indexes and patient reported outcomes (PROs) were considered.

FINDINGS

Common pathogenetic pathways emerged between inflammatory arthritis and mood disorders. Pro-inflammatory mechanisms, such as TNFα, IL-6, IL-17 and oxidative stress factors as well as neurotransmitter alterations at the level of CNS and blood-brain barrier (BBB) cells are involved. The activation of these common pathogenetic pathways is, also, affected by the same triggers, such as smoking, stress, lifestyle, and evidence has emerged concerning the possibility of the clinical efficacy of using the same therapeutic approaches.

CONCLUSIONS

The main causes of the variability in clinical studies outcomes are the rheumatological diseases considered, the prevalence of depression in the general population and in patients with rheumatological diseases and the type of depressive symptom examined. Patients affected by inflammatory arthritis can present symptoms and signs in common with mood disorders, leading to possible clinical overlap. There are still few studies analyzing this concept: they are extremely heterogeneous, both in the characteristics of the population taken into consideration and in the methods used for the definition of depressive disorder, but the suggestions of the data obtained so far are promising and deserve to be pursued.

Experimental and Investigational Pharmacotherapy for Psoriatic Arthritis: Drugs of the Future

In recent years, different studies have shown in psoriatic arthritis (PsA), the pathogenetic role of multiple cytokines other than tumor necrosis factor-α, such as interleukin-17 (IL-17), and IL-23 and dysfunction of Janus kinase (JAK)-signal family pathway. These molecules also represent the target of recently developed biologic (bDMARDs) and targeted synthetic disease modifying antirheumatic drugs (DMARDs) (tsDMARDs) currently investigated in several Phase II and III randomized controlled trials (RCTs). This review examines the therapeutic efficacy and safety of most recent developed IL-17, IL-23 and JAK inhibitors and highlights how these new PsA therapies are going to revolutionize the management of PsA in the next few years. Ongoing RCTs of these molecules in PsA are also described. Available literature on new anti-IL-17 and anti-IL-23 agents and JAK inhibitors demonstrates the potential role of these molecules as effective therapeutic strategies across multiple PsA clinical domains, along with an acceptable tolerability and safety profile, thus expanding the treatment options available for PsA patients. Of note, other molecules are under investigation, and among those, potential therapeutic strategies seem to be represented by single antibodies blocking simultaneously two cytokines, the agents inhibiting mammalian target of rapamycin (mTOR), receptor retinoic acid receptor-related orphan receptor gamma (RORγt), A3 adenosine receptor (A3 AR), and K⁺ channel voltage channel inhibitors. Remarkable progress has been made in PsA pharmacotherapy, and novel bDMARDs targeting IL17A and tsDMARDs (JAK-inhibitors) represent promising therapies. More clinical trials are needed to better characterize the efficacy and safety profile of these therapeutic agents in PsA treatment.

An Update for the Clinician on Biologics for the Treatment of Psoriatic Arthritis

Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy typically associated with psoriasis (PsO). The pathogenesis is strictly related to the association among the presence of genetic risk alleles and innate and acquired immune response with dramatic consequences on bone remodeling. Clinically, PsA patients may present heterogenicity of articular and periarticular manifestations that may be associated with the presence of comorbidities making treatment decision challenging in patients management. The identification of patient-targeted therapies is still a critical issue. Actually, several biological and synthetic drugs are promising in terms of efficacy and safety profile. National and international treatment recommendations support clinicians in the decision of the best treatment, although they may have limits basically related to updates and different outcomes included in the clinical studies evaluated. The aim of this narrative review is therefore to give guidance for clinicians for PsA patients treatment. For this purpose, we evaluated evidence on biological therapies efficacy used for PsA treatment. Specifically, we reviewed data on biological therapies, Janus kinases (JAK) inhibitors, and drugs with a new mechanism of action that are part of the treatment pipeline. The concept of "switching" and "swapping" is also described, as well as data concerning special populations such as pregnant women and elderly patients.

Tackling the autoimmune side in Spondyloarthritis: A systematic review

Spondyloarthritis (SpA) are a heterogeneous group of inflammatory chronic diseases characterized by sharing common pathogenic, clinical and radiologic features. The aim of this review is to support clinicians in understanding and managing this complex disease, from pathogenesis to therapeutic targets, through a systematic review of the current literature in accordance with PRISMA guidelines and checklist. HLA-B27 has been found to be associated with axial involvement either in SA and in PsA patients: it might be involved through presentation of an "arthritogenic peptide" to autoreactive CD8+ T cells or might accumulate in misfolded form and induce production pro-inflammatory cytokines by binding to several innate immune receptors. This genetic background in combination with mechanical stress leads to the activation of both innate and acquired immune responses as well as a possible role of autoimmunity in SpA pathogenesis. The release of IL-23 and IL-17 is relevant for their systemic and local effect on bone, inducing the activation of osteoclasts. Thus, the regulatory role of IL-17 on fibroblasts, osteoblasts and chondrocytes has an impact in both synovial inflammation and joint destruction. Innovative therapies targeting IL-12/23 and IL-17 and the use of small targeted synthetic molecules, as JAK-inhibitors, proved to be effective in SpA patients representing an alternative strategy to TNF-inhibitors.

Metabolic Syndrome and psoriatic arthritis: considerations for the clinician

Introduction: Metabolic Syndrome (MetS) is strictly interconnected with systemic inflammation, and increased evidence has described a close link between this condition and Psoriatic Arthritis (PsA).Areas covered: This review summarizes main studies exploring clinical aspects and prevalence of MetS in PsA cohorts. Further, there is accumulating evidence showing shared inflammatory pathways between MetS, its components, and PsA.Expert opinion: The high prevalence of MetS in PsA highlights the need for screening, evaluation, and close monitoring of MetS and its components (namely, diabetes mellitus, obesity, hypertension, and dyslipidemia) in psoriatic patients.Further studies should focus on the pathogenetic link between MetS and PsA. More studies are required to identify appropriate algorithms for the assessment and management of MetS in PsA patients.

A Multimodal Eye Assessment in Psoriatic Arthritis Patients sine-Psoriasis: Evidence for a Potential Association with Systemic Inflammation

Background: Ocular involvement in Psoriatic Arthritis (PsA) patients is mainly associated with uveitis but there remains a paucity of data on dry eye and retinal abnormalities. We aimed to analyze dry eye and subclinical retinal abnormalities in a cohort of PsA patients sine-psoriasis (PsO). Methods: PsA patients sine-PsO were enrolled. Best-corrected-visual-acuity, ocular-surface-disease-index (OSDI), Schirmer test, tear film breakup-time, standard-automated-perimetry (SAP, mean deviation—MD, pattern standard deviation—PSD), fundus-perimetry (FP), and spectral-domain-optical-coherence-tomography (SD-OCT) were performed. Results: A total of 80 eyes from 40 PsA patients with moderate-severe disease activity, and 70 eyes from 35 healthy control (HC) were evaluated. Higher dry eye prevalence occurred in PsA than HC (p < 0.0001). ESR was positively related with OSDI (p < 0.001) and negatively related with Schirmer (p = 0.007). In PsA, SAP registered higher MD (p < 0.0001) and higher PSD (p = 0.005) in comparison with HC. PSD resulted positively correlated with ESR (p = 0.04) and CRP (p = 0.01), while MD showed a negative correlation with CRP (p = 0.01). Both FP mean differential sensitivity and mean defect were lower in PsA then HC (p < 0.0001). In PsA, FP differential sensitivity was directly related with cumulative steroids (p = 0.02). Conclusions: In PsA patients sine-PsO, dry eye and subclinical abnormalities in visual functions occurred being potentially related to systemic inflammation.

Biologic therapy and spinal radiographic progression in patients with axial spondyloarthritis: A structured literature review

We aimed to perform a structured literature review of spinal radiographic progression, as assessed by the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS), in patients with ankylosing spondylitis (AS) or nonradiographic axial spondyloarthritis (nr-axSpA) treated with biologic therapy. Searches were limited to English language manuscripts published in the 11 years prior to 9 July 2019. Randomized controlled trials, open-label extensions (OLEs) and observational studies reporting mSASSS progression in patients with AS or nr-axSpA treated with biologics were eligible for inclusion. Bias was assessed using the methodological index for nonrandomized studies (MINORS) tool. Among the 322 studies identified in the literature search, 23 (11 OLEs and 12 cohort studies) met the eligibility criteria and were selected for inclusion. Most studies reported mSASSS progression in patients with AS receiving tumor necrosis factor inhibitor (TNFi) treatment. One study reported mSASSS progression in patients with AS treated with secukinumab, an interleukin-17A inhibitor. The mean (range) MINORS score was 11.3 (7-15) for the 15 noncomparative studies and 15 (12-22) for the 8 comparative studies. Although results of the individual studies were variable, mSASSS progression in patients with AS was generally minimal and slow with long-term TNFi therapy. Moreover, odds ratios for the likelihood of mSASSS progression with/without TNFi favoured TNFi therapy in several of the cohort studies. The rate of mSASSS progression following continuous secukinumab treatment was low and remained stable over 4 years. Of two studies reporting progression in patients with nr-axSpA treated with TNFis, one showed no mSASSS progression; however, the lack of control limited comparative conclusions.

Enteropathic spondyloarthritis: Results from a large nationwide database analysis

INTRODUCTION

Spondyloarthrits (SpA) share clinical, genetic and immunological features with Inflammatory Bowel Diseases (IBD), and enteropathic SpA (eSpA) represent the clinical evidence of the association between gut and joint diseases. This cross-sectional study aimed to report data of eSpA patients collected from the first Italian database.

PATIENTS AND METHODS

A specific web-based interface has been created to insert and collect the main clinical, serologic and imaging data from patients with eSpA, as well as disease activity, comorbidities and treatment, in a real-life scenario.

RESULTS

Data were collected in 14 Italian centers (7 rheumatology and 7 gastroenterology units). A total of 347 eSpA patients were enrolled in the study. Type 1 peripheral eSpA was the most frequent form. Crohn' Disease (CD) was the most represented IBD. CD activity was similar among eSpA, whereas UC activity was slightly higher in the axial and mixed form than in the peripheral eSpA. The disease was active in less than half of axial eSpA patients and in only 18% of patients with peripheral eSpA. Furthermore, most of the patients had an inactive IBD. Nineteen percent of the total eSpA patients were free of therapy at the time of the enrollment and 61% of the patients were receiving biotechnological agents.

CONCLUSIONS

The multidisciplinary management of eSpA patients, favored by this ad hoc created web-based platform, allowed to obtain data from the largest eSpA cohort. The information coming of this database might advance knowledge of eSpA and improve their standard of care.

Mediterranean diet and Psoriatic Arthritis activity: a multicenter cross-sectional study

Diet is a modifiable factor implicated in chronic systemic inflammation, and the mediterranean dietary pattern is considered to be a healthy model in terms of morbidity and mortality. The main aim of this study was to evaluate the adherence to the mediterranean diet in patients with Psoriatic Arthritis (PsA) and its impact on disease activity. A cross-sectional observational study was conducted in a cohort of 211 consecutive PsA patients. We evaluated PsA activity by disease activity index for PSoriatic Arthritis (DAPSA) and composite psoriatic disease activity index (CPDAI). The NCEP-ACT III criteria were used to identify subjects with MetS, and in each subject, we evaluated body mass index (BMI). A validated 14-item questionnaire for the assessment of adherence to the mediterranean diet (PREDIMED) was recorded for all the enrolled subjects. Patients showed a median age of 55 (48-62) and disease duration was 76 (36-120) months. 27.01% of patients were classified as having MetS. The median of the mediterranean diet score (MDS) was 7 (6-9). A moderate adherence to mediterranean diet was found in 66.35% of the entire cohort; 15.64% and 18.01% of the patients showed low- and high adherence to the dietary pattern, respectively. We found a negative association between DAPSA and adherence to mediterranean diet (B = - 3.291; 95% CI - 5.884 to - 0.698). DAPSA was positively associated with BMI (B = 0.332; 95% CI 0.047-0.618) and HAQ ( B = 2.176; 95% CI 0.984-3.368). Results from our study evidenced that in PsA patients, higher levels of disease activity as measured by DAPSA correlated with low adherence to mediterranean diet, suggesting potential benefit of antinflammatory properties of this dietary pattern.

The Gut Microbiome in Inflammatory Bowel Disease: Lessons Learned From Other Immune-Mediated Inflammatory Diseases

There is a growing appreciation for the role of the gut microbiome in human health and disease. Aided by advances in sequencing technologies and analytical methods, recent research has shown the healthy gut microbiome to possess considerable diversity and functional capacity. Dysbiosis of the gut microbiota is believed to be involved in the pathogenesis of not only diseases that primarily affect the gastrointestinal tract but also other less obvious diseases, including neurologic, rheumatologic, metabolic, hepatic, and other illnesses. Chronic immune-mediated inflammatory diseases (IMIDs) represent a group of diseases that share many underlying etiological factors including genetics, aberrant immunological responses, and environmental factors. Gut dysbiosis has been reported to be common to IMIDs as a whole, and much effort is currently being directed toward elucidating microbiome-mediated disease mechanisms and their implications for causality. In this review, we discuss gut microbiome studies in several IMIDs and show how these studies can inform our understanding of the role of the gut microbiome in inflammatory bowel disease.

Interactions between microbiota, diet/nutrients and immune/inflammatory response in rheumatic diseases: focus on rheumatoid arthritis

Rheumatic and musculoskeletal diseases (RMDs) are chronic systemic immune/inflammatory conditions characterized by the interaction between gene predisposition, autoimmunity and environmental factors. A growing scientific interest has focused on the role of diet in RMDs, suggesting its significant contribution to the pathogenesis and prognosis of these diseases. It is now clear that diet can directly modulate the immune response by providing a wide range of nutrients, which interfere with multiple pathways at both the gastro-intestinal and systemic level. Moreover, diet critically shapes the human gut microbiota, which is recognized to have a central role in the modulation of the immune response and in RMD pathogenesis. We hereby provide an in-depth analysis on the role of the microbiota in RMDs and on nutritional intervention as an integral part of a multidisciplinary approach. Particular attention will be given to the Mediterranean diet, as the only diet proven to support substantial benefits in RMD management.

Pathogenetic Therapy of Psoriasis by Muramyl Peptide

Psoriasis is a multifactorial disease with a dysregulation in immune system. The aim of this study was to survey the clinical efficacy and safety of muramyl peptide—the ligand of the receptors of innate immunity (drug Licopid, AO Peptek, Moscow, Russia) in patients with psoriasis. The effect of muramyl peptide on 86 patients with different severity of plaque psoriasis was tested. The Psoriasis Area and Severity Index (PASI), cytokine status and production of nitric oxide in blood serum, and the subsequent course of psoriasis have been evaluated. Evaluation of significance of observed differences was presented by the Student's t-test. As a result of the treatment, clinical cure or improvement was detected in 98.2% of patients (p < 0.05), while 24.4% had a complete cure. Subsequent observations during 4 years showed that patients who received muramyl peptide statistically significantly increased relapse-free period. Moreover, subsequent relapses of the disease after treatment with muramyl peptide were in much more milder form in the cases of mild psoriasis. The conducted studies showed that monotherapy with muramyl peptide stopped the clinical manifestations of psoriasis, normalized the processes of cytokine-dependent [interleukin (IL)−4, IL-10, IL-12, tumor necrosis factor alpha (TNF-α)] regulation of the immune response and nonspecific resistance, expressed in a decreasing amount of serum antigens sCD54 [soluble intercellular adhesion molecule-1 (sICAM-1)] to reference values (p ≤ 0.01). Taken together, our research demonstrated the effectiveness of therapy with muramyl peptide and moreover, that elevated levels of sCD54 and MIF (p ≤ 0.01) in the serum of patients with psoriasis considered as potential biomarkers of the severityof psoriasis and control over their dynamics have prognostic significance in determining the effectiveness of the therapy.

An update on pathogenesis of psoriatic arthritis and potential therapeutic targets

Introduction: Innate immune response and bone remodeling are key factors contributing to the pathogenesis of psoriatic arthritis (PsA). Moreover, the evidence of autoantibodies in patients' sera suggests an autoimmune side in PsA. Besides the immune pathways, studies strongly support the role of genetic risk alleles in affecting the clinical heterogeneity of PsA as well as the response to therapy. A good clinical response to treatment, indeed, represents a challenge in PsA patients and the identification of patient-targeted therapies is still a critical issue. Areas covered: We performed a systematic review aiming at describing new evidence on PsA pathogenesis and treatments. Reported items for systematic reviews (PRISMA checklist) were analyzed. Studies included from the PubMed database addressed the following items: innate immunity, autoimmunity, bone remodeling, and therapeutic targets in PsA; time frame of research 1970-2019. Specifically, we reviewed data on IL-17 inhibitors, abatacept, JAK inhibitors, ABT 122, and A (3) adenosine receptors agonist, CF101. Expert opinion: In PsA an intriguing pathogenetic network has been documented. Several biological and synthetic drugs are promising in terms of efficacy and safety profile.

Pain and affective distress in arthritis: relationship to immunity and inflammation

INTRODUCTION

Most arthritides are associated with pain and psychological distress (clinically significant depression and anxiety). Pain and depression are mutually exacerbating; both may continue even when joint involvement appears well controlled. Area covered: There is strong evidence that arthritis-related stress impacts the central nervous system and, together with peripheral inflammatory changes, can cause central sensitization that can lead to chronic pain and worsening of affective distress. Cytokines and chemokines participate both in joint inflammation and in central sensitization. We review evidence of these relationships in five arthritides, namely rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, gout, and in osteoarthritis of the hips and knees. Central sensitization in these conditions results in long-lasting pain and psychological distress. Expert commentary: Chronic pain and depression are important but often neglected in the clinical assessment and treatment of arthritis. The potential role of biologic cytokines and Janus kinase inhibitors in dealing with these symptoms needs further study.

Potential Role of Cytochrome c and Tryptase in Psoriasis and Psoriatic Arthritis Pathogenesis: Focus on Resistance to Apoptosis and Oxidative Stress

Psoriasis (PsO) is an autoimmune disease characterized by keratinocyte proliferation, chronic inflammation and mast cell activation. Up to 42% of patients with PsO may present psoriatic arthritis (PsA). PsO and PsA share common pathophysiological mechanisms: keratinocytes and fibroblast-like synoviocytes are resistant to apoptosis: this is one of the mechanism facilitating their hyperplasic growth, and at joint level, the destruction of articular cartilage, and bone erosion and/or proliferation. Several clinical studies regarding diseases characterized by impairment of cell death, either due to apoptosis or necrosis, reported cytochrome c release from the mitochondria into the extracellular space and finally into the circulation. The presence of elevated cytochrome c levels in serum has been demonstrated in diseases as inflammatory arthritis, myocardial infarction and stroke, and liver diseases. Cytochrome c is a signaling molecule essential for apoptotic cell death released from mitochondria to the cytosol allowing the interaction with protease, as the apoptosis protease activation factor, which lead to the activation of factor-1 and procaspase 9. It has been demonstrated that this efflux from the mitochondria is crucial to start the intracellular signaling responsible for apoptosis, then to the activation of the inflammatory process. Another inflammatory marker, the tryptase, a trypsin-like serine protease produced by mast cells, is released during inflammation, leading to the activation of several immune cells through proteinase-activated receptor-2. In this review, we aimed at discussing the role played by cytochrome c and tryptase in PsO and PsA pathogenesis. To this purpose, we searched pathogenetic mechanisms in PUBMED database and review on oxidative stress, cytochrome c and tryptase and their potential role during inflammation in PsO and PsA. To this regard, the cytochrome c release into the extracellular space and tryptase may have a role in skin and joint inflammation.

Intestinal barrier integrity in patients with plaque psoriasis

Psoriasis is a chronic inflammatory systemic disease. Growing evidence suggests that human homeostasis depends on a mutualistic relationship with gut bacteria that produce a number of biologically active compounds. Therefore, enteric microbiota dysbiosis with gut barrier disruption may be an important factor in the development of chronic inflammatory diseases. The aim of our study was to assess non-invasive markers of intestinal barrier integrity in patients with moderate to severe psoriasis. Concentrations of claudin-3 (intestinal epithelial tight junction structure) and intestinal fatty acid binding protein (I-FABP; marker of enterocyte damage) were determined in the blood of patients with chronic plaque psoriasis (n = 20) and healthy individuals (n = 20) using commercially available enzyme-linked immunoassay test kits. Claudin-3 concentration was higher in patients with psoriasis compared with healthy control (median, 54.07 vs 42.36 ng/mL; P < 0.001). Patients with psoriasis also had elevated concentration of plasma I-FABP (median, 708.8 vs 147.1 pg/mL; P < 0.05). Our results support the hypothesis that dysfunction of the intestinal barrier in psoriasis disturbs the homeostatic equilibrium between the microbiota and immune system. Further studies are needed in order to develop new therapeutic interventions based on modulation of intestinal permeability.

Nature versus nurture in the spectrum of rheumatic diseases: Classification of spondyloarthritis as autoimmune or autoinflammatory

Spondyloarthritides (SpA) include inflammatory joint diseases with various clinical phenotypes that may also include the axial skeleton and/or entheses. SpA include psoriatic arthritis, reactive arthritis, enteropathic arthritis and ankylosing spondylitis; the latter is frequently associated with extra-articular manifestations, such as uveitis, psoriasis, and inflammatory bowel disease. SpA are associated with the HLA-B27 allele and recognize T cells as key pathogenetic players. In contrast to other rheumatic diseases, SpA affect women and men equally and are not associated with detectable serum autoantibodies. In addition, but opposite to rheumatoid arthritis, SpA are responsive to treatment regimens including IL-23 or IL-17-targeting biologics, yet are virtually unresponsive to steroid treatment. Based on these differences with prototypical autoimmune diseases, such as rheumatoid arthritis or connective tissue diseases, SpA may be better classified among autoinflammatory diseases, with a predominant innate immunity involvement. This would rank SpA closer to gouty arthritis and periodic fevers in the spectrum of rheumatic diseases, as opposed to autoimmune-predominant diseases. We herein provide available literature on risk factors associated with SpA in support of this hypothesis with a specific focus on genetic and environmental factors.