Dynamics of inflammation-associated plasma proteins following faecal microbiota transplantation in patients with psoriatic arthritis and healthy controls: exploratory findings from the FLORA trial.

OBJECTIVES: The gut microbiota can mediate both pro and anti-inflammatory responses. In patients with psoriatic arthritis (PsA), we investigated the impact of faecal microbiota transplantation (FMT), relative to sham transplantation, on 92 inflammation-associated plasma proteins. METHODS: This study relates to the FLORA trial cohort, where 31 patients with moderate-to-high peripheral PsA disease activity, despite at least 3 months of methotrexate treatment, were included in a 26-week, double-blind, randomised, sham-controlled trial. Participants were allocated to receive either one gastroscopic-guided healthy donor FMT (n=15) or sham (n=16). Patient plasma samples were collected at baseline, week 4, 12 and 26 while samples from 31 age-matched and sex-matched healthy controls (HC) were collected at baseline. Samples were analysed using proximity extension assay technology (Olink Target-96 Inflammation panel). RESULTS: Levels of 26 proteins differed significantly between PsA and HC pre-FMT (adjusted p<0.05), of which 10 proteins were elevated in PsA: IL-6, CCL20, CCL19, CDCP1, FGF-21, HGF, interferon-γ (IFN-γ), IL-18R1, monocyte chemotactic protein 3, and IL-2. In the FMT group, levels of 12 proteins changed significantly across all timepoints (tumour necrosis factor (TNF), CDCP1, IFN-γ, TWEAK, signalling lymphocytic activation molecule (SLAMF1), CD8A, CD5, Flt3L, CCL25, FGF-23, CD6, caspase-8). Significant differences in protein levels between FMT and sham-treated patients were observed for TNF (p=0.002), IFN-γ (p=0.011), stem cell factor (p=0.024), matrix metalloproteinase-1 (p=0.038), and SLAMF1 (p=0.042). FMT had the largest positive effect on IFN-γ, Axin-1 and CCL25 and the largest negative effect on CCL19 and IL-6. CONCLUSIONS: Patients with active PsA have a distinct immunological plasma protein signature compared with HC pre-FMT. FMT affects several of these disease markers, including sustained elevation of IFN-γ. TRIAL REGISTRATION NUMBER: NCT03058900.

Contemporary outcomes of primary total hip arthroplasty in patients with inflammatory arthritis.

Aims: Contemporary outcomes of primary total hip arthroplasties (THAs) with highly cross-linked polyethylene (HXLPE) liners in patients with inflammatory arthritis have not been well studied. This study examined the implant survivorship, complications, radiological results, and clinical outcomes of THA in patients with inflammatory arthritis. Methods: We identified 418 hips (350 patients) with a primary diagnosis of inflammatory arthritis who underwent primary THA with HXLPE liners from January 2000 to December 2017. Of these hips, 68% had rheumatoid arthritis (n = 286), 13% ankylosing spondylitis (n = 53), 7% juvenile rheumatoid arthritis (n = 29), 6% psoriatic arthritis (n = 24), 5% systemic lupus erythematosus (n = 23), and 1% scleroderma (n = 3). Mean age was 58 years (SD 14.8), 66.3% were female (n = 277), and mean BMI was 29 kg/m2 (SD 7). Uncemented femoral components were used in 77% of cases (n = 320). Uncemented acetabular components were used in all patients. Competing risk analysis was used accounting for death. Mean follow-up was 4.5 years (2 to 18). Results: The ten-year cumulative incidence of any revision was 3%, and was highest in psoriatic arthritis patients (16%). The most common indications for the 15 revisions were dislocations (n = 8) and periprosthetic joint infections (PJI; n = 4, all on disease-modifying antirheumatic drugs (DMARDs)). The ten-year cumulative incidence of reoperation was 6.1%, with the most common indications being wound infections (six cases, four on DMARDs) and postoperative periprosthetic femur fractures (two cases, both uncemented femoral components). The ten-year cumulative incidence of complications not requiring reoperation was 13.1%, with the most common being intraoperative periprosthetic femur fracture (15 cases, 14 uncemented femoral components; p = 0.13). Radiological evidence of early femoral component subsidence was observed in six cases (all uncemented). Only one femoral component ultimately developed aseptic loosening. Harris Hip Scores substantially improved (p < 0.001). Conclusion: Contemporary primary THAs with HXLPE in patients with inflammatory arthritis had excellent survivorship and good functional outcomes regardless of fixation method. Dislocation, PJI, and periprosthetic fracture were the most common complications in this cohort with inflammatory arthritis.

Psoriatic Arthritis: Pathogenesis and Targeted Therapies.

Psoriatic arthritis (PsA), a heterogeneous chronic inflammatory immune-mediated disease characterized by musculoskeletal inflammation (arthritis, enthesitis, spondylitis, and dactylitis), generally occurs in patients with psoriasis. PsA is also associated with uveitis and inflammatory bowel disease (Crohn's disease and ulcerative colitis). To capture these manifestations as well as the associated comorbidities, and to recognize their underlining common pathogenesis, the name of psoriatic disease was coined. The pathogenesis of PsA is complex and multifaceted, with an interplay of genetic predisposition, triggering environmental factors, and activation of the innate and adaptive immune system, although autoinflammation has also been implicated. Research has identified several immune-inflammatory pathways defined by cytokines (IL-23/IL-17, TNF), leading to the development of efficacious therapeutic targets. However, heterogeneous responses to these drugs occur in different patients and in the different tissues involved, resulting in a challenge to the global management of the disease. Therefore, more translational research is necessary in order to identify new targets and improve current disease outcomes. Hopefully, this may become a reality through the integration of different omics technologies that allow better understanding of the relevant cellular and molecular players of the different tissues and manifestations of the disease. In this narrative review, we aim to provide an updated overview of the pathophysiology, including the latest findings from multiomics studies, and to describe current targeted therapies.

Risk of incident type 2 diabetes in patients with psoriatic arthritis: A systematic review and meta-analysis of cohort studies.

OBJECTIVES: To determine the risk of type 2 diabetes among patients with psoriatic arthritis (PsA). METHODS: Electronic database searches of PubMed, EMBASE and Cochrane Library were performed from inception to June 2020 and updated in May 2022. Cohort studies were included if they reported hazard ratios (HR) or relative risks with 95% confidence interval (CI) of incident diabetes in patients with PsA compared with non-rheumatic populations. Pooled HR and 95% CI were calculated using a DerSimonian and Laird method random-effects model. RESULTS: A total of 5 studies comprising 37 811 PsA patients with 174 825 patient-years and 476 838 non-rheumatic controls with 2 945 358 patient-years were identified and included in our data analysis. During the follow-up, 2335 and 23 035 incident diabetes were observed in PsA and non-rheumatic control groups, corresponding to a crude incidence rate of 13.4 and 7.8 per 1000 patient-years, respectively. The pooled age- and gender-adjusted, and fully adjusted HR of incident diabetes in patients with PsA compared with non-rheumatic populations were 1.54 (95% CI: 1.43-1.67, I2  = 50.8%) and 1.38 (95% CI: 1.31-1.47, I2  = 0.0%), respectively. CONCLUSIONS: Our study indicates a 38% increase in the risk of type 2 diabetes among patients with PsA, with an incidence rate of 13.4 per 1000 patients-years. These findings suggest the awareness of managing diabetes with careful screening of PsA patients in daily practice.

Beyond plaque psoriasis - pathogenesis and treatment of other psoriasis phenotypes.

PURPOSE OF REVIEW: Psoriasis vulgaris is the commonest presentation of psoriatic disease, but morphologic variants such as pustular psoriasis (PP) and a closely related disease, pityriasis rubra pilaris (PRP), have been known for a long time, have been associated with rheumatologic manifestations indistinguishable from psoriatic arthritis (PsA) that may go unrecognized, and often represent a therapeutic conundrum. There is recent evidence that underlying genetic and pathogenetic differences may provide the basis for newer therapeutic approaches. RECENT FINDINGS: This narrative review highlights the clinical, genetic and pathogenetic characteristics of PP and PRP, their association with PsA and recent developments in their treatment, especially with biologic agents targeting IL-36 and other cytokines of pathogenic relevance. SUMMARY: The clinical manifestations of PP and PRP are less well known to rheumatologists than those of psoriasis, and recent advances in our insight on their pathogenesis may eventually overcome the therapeutic difficulties faced by dermatologists and rheumatologists in the management of these diseases and their rheumatologic manifestations.

Association of Structural Entheseal Lesions With an Increased Risk of Progression From Psoriasis to Psoriatic Arthritis.

OBJECTIVE: To test whether the presence of structural entheseal lesions in psoriasis patients influences the risk of progression to psoriatic arthritis (PsA). METHODS: We conducted a prospective cohort study of psoriasis patients without clinical evidence of musculoskeletal involvement who underwent baseline assessment of structural entheseal lesions and volumetric bone mineral density (vBMD) at entheseal and intraarticular sites by high-resolution peripheral quantitative computed tomography. Adjusted relative risks of developing PsA associated with baseline vBMD and the presence of structural entheseal lesions were calculated using multivariable Cox regression models. RESULTS: The cohort included 114 psoriasis patients (72 men and 42 women) with a mean ± SD follow-up duration of 28.2 ± 17.7 months, during which 24 patients developed PsA (9.7 per 100 patient-years [95% confidence interval (95% CI) 6.2-14.5]). Patients with structural entheseal lesions were at higher risk of developing PsA compared to patients without such lesions (21.4 per 100 patient-years [95% CI 12.5-34.3]; hazard ratio [HR] 5.10 [95% CI 1.53-16.99], P = 0.008). With respect to vBMD, a 1-SD increase in entheseal, but not intraarticular, vBMD was associated with an ~30% reduced risk of progression to PsA. Especially, higher cortical vBMD at entheseal segments was associated with a lower risk of developing PsA (HR 0.32 per 1 SD [95% CI 0.14-0.71]), and the association remained robust after multiple imputation of missing data (HR 0.64 [95% CI 0.42-0.98]). CONCLUSION: The presence of structural entheseal lesions as well as low cortical vBMD at entheseal segments are associated with an increased risk of developing PsA in patients with psoriasis.

Being overweight is associated with not reaching low disease activity in women but not men with psoriatic arthritis.

OBJECTIVE: To assess sex differences in disease activity parameters and health-related quality of life in PsA, and to assess whether determinants associated with not reaching treatment target differed between men and women. METHODS: Routine practice data of 855 PsA patients, who were all tightly monitored and treated, was used. Sex differences including, but not limited to, PsA Disease Activity Score (PASDAS), skin/nail disease, SF-12 PCS/MCS, and inflammatory back pain (IBP) were assessed. Multivariate analyses were used to examine determinants associated with not reaching treatment target (PASDAS ≤ 3.2) in men and women. RESULTS: Women had worse scores for-among others-swollen and tender joints, CRP, enthesitis and function (all P < 0.001). Higher PASDAS scores were found for women [3.5 (1.5)] than men [2.7 (1.5), P < 0.001]. Likewise, women were more often not at PASDAS treatment target (OR = 2.03, P < 0.001). No difference in current medication use was found. Nail disease, IBP, number of DMARDs used (past and current), and BMI were associated with not reaching treatment target in the overall sample. For women, but not men, BMI was associated with not reaching PASDAS low disease activity (LDA) (OR between 2.41 and 3.43, P < 0.001). CONCLUSIONS: Women with PsA in a tightly monitored and treated setting have more severe disease than men. This is demonstrated by worse scores for women in both subjective and objective disease activity measures, in addition to women less often reaching the treatment target. Notably, being overweight is associated with higher disease activity in women, but not men.

Using Bayesian networks to identify musculoskeletal symptoms influencing the risk of developing psoriatic arthritis in people with psoriasis.

OBJECTIVES: The aim of this study was to explore the use of Bayesian networks (BNs) to understand the relationships between musculoskeletal symptoms and the development of PsA in people with psoriasis. METHODS: Incident cases of psoriasis were identified for 1998 to 2015 from the UK Clinical Research Practice Datalink. Musculoskeletal symptoms (identified by Medcodes) were concatenated into primary groups, each made up of several subgroups. Baseline demographics for gender, age, BMI, psoriasis severity, alcohol use and smoking status were also extracted. Several BN structures were composed using a combination of expert knowledge and data-oriented modelling based on: (i) primary musculoskeletal symptom groups; (ii) musculoskeletal symptom subgroups and (iii) demographic variables. Predictive ability of the networks using the area under the receiver operating characteristic curve was calculated. RESULTS: Over one million musculoskeletal symptoms were extracted for the 90 189 incident cases of psoriasis identified, of which 1409 developed PsA. The BN analysis yielded direct relationships between gender, BMI, arthralgia, finger pain, fatigue, hand pain, hip pain, knee pain, swelling, back pain, myalgia and PsA. The best BN, achieved by using the more site-specific musculoskeletal symptom subgroups, was 76% accurate in predicting the development of PsA in a test set and had an area under the receiver operating characteristic curve of 0.73 (95% CI: 0.70, 0.75). CONCLUSION: The presented BN model may be a useful method to identify clusters of symptoms that predict the development of PsA with reasonable accuracy. Using a BN approach, we have shown that there are several symptoms which are predecessors of PsA, including fatigue, specific types of pain and swelling.

Pathogenesis of psoriatic arthritis.

Psoriatic arthritis (PsA) is a heterogenous systemic inflammatory disorder which affects peripheral joints (PsA) and skin (psoriasis (Ps)), but also causes inflammation at entheseal sites, digits (dactylitis) and the axial skeleton. Over the past decade, there have been considerable advances both in our understanding of the pathogenesis of PsA and in the treatment of its diverse manifestations. This article reviews our current knowledge of the pathogenesis of PsA, and how genetic pre-disposition coupled with mechanical stress may influence the development of the pathognomonic features of PsA including enthesitis and osteoproliferation, with concomitant osteoporosis and erosive disease. We consider factors that influence the development of PsA in patients with Ps, and how improving our knowledge of the phenotypes of PsA may ultimately facilitate our goal of precision medicine, a key unmet need as defined by the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis.

Navigating the diverse immune landscapes of psoriatic arthritis.

The goal of remission in psoriatic arthritis (PsA) has remained elusive despite the influx of a range of new therapies over the last 20 years. In contrast, therapeutic responses to agents that inhibit IL-23 or IL-17 have demonstrated impressive efficacy in psoriasis. In part, the divergent responses in these two disorders are likely related to the heterogeneity of tissue involvement in PsA and the interplay of multiple different cell populations and molecular pathways. In this narrative review, we will examine the plasticity of the immune response in PsA from the perspective of the Th17 cell and monocyte and discuss recent findings regarding the importance of CD8+ T resident cells in disease pathogenesis. We will then examine the effects of cytokines on epithelial cell and stromal populations and finally discuss new data regarding immune cell and tissue resident cell cross-talk in entheses and bone. Lastly, the potential therapeutic targets that have emerged from these investigations will be discussed.

IL-12p40/IL-23p40 Blockade With Ustekinumab Decreases the Synovial Inflammatory Infiltrate Through Modulation of Multiple Signaling Pathways Including MAPK-ERK and Wnt.

Background: Psoriatic arthritis (PsA) is a chronic inflammatory joint disease within the spondyloarthritis spectrum. IL-12p40/IL-23p40 blockade reduces PsA disease activity, but its impact on synovial inflammation remains unclear. Objectives: To investigate the cellular and molecular pathways affected by IL-12p40/IL-23p40 blockade with ustekinumab in the synovium of PsA patients. Methods: Eleven PsA patients with at least one inflamed knee or ankle joint were included in a 24-week single-center open-label study and received ustekinumab 45 mg/sc according to standard care at week 0, 4, and 16. Besides clinical outcomes, synovial tissue (ST) samples were obtained by needle arthroscopy from an inflamed knee or ankle joint at baseline, week 12 and 24 and analyzed by immunohistochemistry, RNA-sequencing and real-time quantitative polymerase chain reaction (qPCR). Results: We obtained paired baseline and week 12, and paired baseline, week 12 and 24 ST samples from nine and six patients, respectively. Eight patients completed 24 weeks of clinical follow-up. At 12 weeks 6/11 patients met ACR20, 2/11 met ACR50 and 1/11 met ACR70 improvement criteria, at 24 weeks this was 3/8, 2/8 and 1/8 patients, respectively. Clinical and serological markers improved significantly. No serious adverse events occurred. We observed numerical decreases of all infiltrating cell subtypes at week 12, reaching statistical significance for CD68+ sublining macrophages. For some cell types this was even more pronounced at week 24, but clearly synovial inflammation was incompletely resolved. IL-17A and F, TNF, IL-6, IL-8, and IL-12p40 were not significantly downregulated in qPCR analysis of W12 total biopsies, only MMP3 and IL-23p19 were significantly decreased. RNA-seq analysis revealed 178 significantly differentially expressed genes between baseline and 12 weeks (FDR 0.1). Gene Ontology and KEGG terms enrichment analyses identified overrepresentation of biological processes as response to reactive oxygen species, chemotaxis, migration and angiogenesis as well as MAPK-ERK and PI3K-Akt signaling pathways among the downregulated genes and of Wnt signaling pathway among the upregulated genes. Furthermore, ACR20 responders and non-responders differed strikingly in gene expression profiles in a post-hoc exploratory analysis. Conclusions: Ustekinumab suppresses PsA synovial inflammation through modulation of multiple signal transduction pathways, including MAPK-ERK, Wnt and potentially PI3K-Akt signaling rather than by directly impacting the IL-17 pathway.

Insights into the pathogenesis of psoriatic arthritis from genetic studies.

Psoriatic arthritis (PsA) is a relatively common inflammatory arthritis, a spondyloarthritis (SpA), that occurs most often in patients with psoriasis, a common immune-mediated inflammatory skin disease. Both psoriasis and PsA are highly heritable. Genetic and recent genomic studies have identified variants associated with psoriasis and PsA, but variants differentiating psoriasis from PsA are few. In this review, we describe recent developments in understanding the genetic burden of PsA, linkage, association and epigenetic studies. Using pathway analysis, we provide further insights into the similarities and differences between PsA and psoriasis, as well as between PsA and other immune-mediated inflammatory diseases, particularly ankylosing spondylitis, another SpA. Environmental factors that may trigger PsA in patients with psoriasis are also reviewed. To further understand the pathogenetic differences between PsA and psoriasis as well as other SpA, larger cohort studies of well-phenotyped subjects with integrated analysis of genomic, epigenomic, transcriptomic, proteomic and metabolomic data using interomic system biology approaches are required.

Predicting the Risk of Psoriatic Arthritis in Plaque Psoriasis Patients: Development and Assessment of a New Predictive Nomogram.

Objective: This study aimed to develop a risk of psoriatic arthritis (PsA) predictive model for plaque psoriasis patients based on the available features. Methods: Patients with plaque psoriasis or PsA were recruited. The characteristics, skin lesions, and nail clinical manifestations of the patients have been collected. The least absolute shrinkage was used to optimize feature selection, and logistic regression analysis was applied to further select features and build a PsA risk predictive model. Calibration, discrimination, and clinical utility of the prediction model were evaluated by using the calibration plot, C-index, the area under the curve (AUC), and decision curve analysis. Internal validation was performed using bootstrapping validation. The model was subjected to external validation with two separate cohorts. Results: Age at onset, duration, nail involvement, erythematous lunula, onychorrhexis, oil drop, and subungual hyperkeratosis were presented as predictors to perform the prediction nomogram. The predictive model showed good calibration and discrimination (C-index: 0.759; 95% CI: 0.707-0.811). The AUC of this prediction model was 0.7578092. Excellent performances of the C-index were reached in the internal validation and external cohort validation (0.741, 0.844, and 0.845). The decision curve indicated good effect of the PsA nomogram in guiding clinical practice. Conclusion: This novel PsA nomogram could assess the risk of PsA in plaque psoriasis patients with good efficiency.

The causal effect of interleukin-17 on the risk of psoriatic arthritis: a Mendelian randomization study.

OBJECTIVE: To determine causal associations between genetically predicted TNF-α, IL-12p70 and IL-17 levels and risk of PsA. METHODS: The publicly available summary-level findings from genome-wide association studies (GWAS) was used to identify loci influencing normal physiological concentrations of TNF-α, IL-12p70 and IL-17 (n = 8293) among healthy individuals as exposure and a GWAS for PsA from the UK Biobank (PsA = 900, control = 462 033) as the outcome. A two-sample Mendelian randomization (MR) analysis was performed using the inverse-variance weighted (IVW), weighted median and MR-Egger regression methods. Sensitivity analysis and MR-Egger regression analysis were performed to evaluate the heterogeneity and pleiotropic effects of each variant. RESULTS: Single-nucleotide polymorphisms (SNPs) at genome-wide significance from GWASs on TNF-α, IL-12p70 and IL-17 were identified as the instrumental variables. The IVW method indicated a causal association between increased IL-17 level and risk of PsA (ß = -0.00186 per allele, s.e. = 0.00043, P = 0.002). Results were consistent in the weighted median method (ß = -0.00145 per allele, s.e. = 0.00059, P = 0.014) although the MR-Egger method suggested a non-significant association (ß = -0.00133 per allele, s.e. = 0.00087; P = 0.087). Single SNP MR results revealed that the C allele of rs117556572 was robustly associated with risk of PsA (ß = 0.00210, s.e. = 0.00069, P = 0.002). However, no evidence for a causal effect was observed between TNF-α, IL-12p70, decreased IL-17 levels and risk of PsA. CONCLUSION: Our findings provide preliminary evidence that genetic variants predisposing to higher physiological IL-17 level are associated with decreased risk of PsA.