The gut in spondyloarthritis

The Gut-Vascular Barrier as a New Protagonist in Intestinal and Extraintestinal Diseases

The intestinal barrier, with its multiple layers, is the first line of defense between the outside world and the intestine. Its disruption, resulting in increased intestinal permeability, is a recognized pathogenic factor of intestinal and extra-intestinal diseases. The identification of a gut-vascular barrier (GVB), consisting of a structured endothelium below the epithelial layer, has led to new evidence on the etiology and management of diseases of the gut-liver axis and the gut-brain axis, with recent implications in oncology as well. The gut-brain axis is involved in several neuroinflammatory processes. In particular, the recent description of a choroid plexus vascular barrier regulating brain permeability under conditions of gut inflammation identifies the endothelium as a key regulator in maintaining tissue homeostasis and health.

Diet and Disease Activity in Patients with Axial Spondyloarthritis: SpondyloArthritis and NUTrition Study (SANUT)

Axial Spondyloarthritis (axSpA) patients with inflamed intestines have higher SpA activity. Diets that modulate microbiota may influence inflammation and SpA activity. Today, data concerning the impact of diet on SpA activity are scarce. SANUT was a single-center, noninterventional, cohort study that assessed dietetic profiles associated with SpA activity in axSpA. Demographic, clinical, SpA-related, quality of life (QoL), fatigue, physical activity, and dietary data were collected. SpA activity was assessed by Ankylosing Spondylitis Disease Activity Score (ASDAS) and by Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). We assessed whether high SpA activity was associated with nutriment consumption. Between 12 February 2018 and 12 February 2020, 278 patients participated. High SpA activity, as measured by ASDAS and BASDAI, was significantly associated with higher body mass index and waist circumference, negative HLA-B27, lower QoL, higher fatigue, and higher digestive-symptom scores. Furthermore, high SpA activity, as measured by BASDAI, was associated with female sex, smoking status, patients who were not actively employed, reduced physical activity, and high intake of ultra-transformed foods, while high SpA activity, as measured by ASDAS, was associated with low intake of omega-3 PUFAs and fiber. Therefore, low intakes of omega-3 PUFAs and fiber, and high intake of ultra-transformed foods, are associated with high SpA activity.

World mortality of ankylosing spondylitis, psoriatic arthritis and inflammatory bowel disease in 2015 and its evolution from 2001 to 2015

OBJECTIVE

There is little epidemiological data on global mortality in spondyloarthritis (SpA) and inflammatory bowel disease. We then determined mortality rates of ankylosing spondylitis (AS), psoriatic arthritis (PsA), Crohn's disease (CD) and ulcerative colitis (UC) both globally and by country, and to describe their evolution between 2001 and 2015.

METHODS

We used mortality data from the World Health Organisation (WHO), which shows the number of deaths classified by age, sex, and cause of death coded by ICD-10. Age-standardized mortality rates (ASMR) were constructed using the 2015 WHO reference population. Temporal trend analyses of ASMR were performed between 2001 and 2015 using joinpoint regression.

RESULTS

Global ASMR was for 0.13 [0.11-0.14] deaths per million inhabitants for AS, 0.04 [0.03-0.05] for PsA, 0.86 [0.82-0.89] for CD and 0.76 [0.73-0.79] for UC. The worldwide trend analysis showed no significant change in ASMR for AS, a statistically significant increase from 2004 to 2015 (mean annual percent change (APC): 5.94%, p<0.001) for PsA, and a statistically significant decrease from 2001 to 2015 for CD (mean APC: -0.82%, p<0.001) and UC (mean APC: -1.29%, p<0.001). Statistically significant geographical disparities were identified.

CONCLUSION

We found significant geographical disparities in SpA and IBD mortality across the world. Further studies seem to be needed to better understand the evolution of mortality over the last twenty years.

Fecal calprotectin as a biomarker of microscopic bowel inflammation in patients with spondyloarthritis

AIM

Microscopic bowel inflammation is present in up to 60% of all patients with spondyloarthritis (SpA) and appears to be associated with more severe joint disease and a higher risk of developing inflammatory bowel disease (IBD). This study aimed to determine the utility of fecal calprotectin (fCAL) in evaluating endoscopic and histological bowel inflammation in SpA patients.

METHODS

Ileocolonoscopies with biopsies and fCAL measurements were performed in 65 patients with SpA.

RESULTS

In 47 (72.3%) patients, the fCAL levels were higher than 50 μg/g, whereas in 20 (30.7%), these levels were greater than 250 μg/g. A total of 38 (58.5%) patients presented with microscopic bowel inflammation, and 13 (20%) presented with signs of endoscopic inflammation. fCAL levels were significantly higher in patients with microscopic bowel inflammation than in those without inflammatory findings (P < .001); additionally, these levels were slightly higher in patients with endoscopic signs of bowel inflammation (P = .053). A fCAL cutoff value of 96 μg/g predicted histological bowel inflammation with 73% sensitivity and 67% specificity. No statistically significant difference was observed in the fCAL levels between patients who had been treated or not treated with nonsteroidal anti-inflammatory drugs (NSAIDs).

CONCLUSION

Our findings confirm a high prevalence of microscopic bowel inflammation in SpA patients, regardless of the use of NSAIDs. The evaluation of fCAL levels proved to be useful in the identification of microscopic inflammation and could help in the more judicious indication of ileocolonoscopy. These results support the use of fCAL for the evaluation of microscopic bowel inflammation in SpA patients.

Intestinal permeability in spondyloarthritis and rheumatoid arthritis: A systematic review of the literature

OBJECTIVES

To describe the current methods usable to assess intestinal permeability in spondyloarthritis (SpA) and rheumatoid arthritis (RA), to analyze the available data on intestinal permeability in SpA and RA patients and the effects of drugs such as non-steroidal anti-inflammatory drugs (NSAIDs) on intestinal permeability.

METHODS

A systematic review was conducted. Medline, Embase, and Cochrane Library databases were searched. Studies published in the last 40 years (January 1980-September 2020) with patients with SpA and/or RA assessing the intestinal permeability were selected.

RESULTS

A total of 2916 articles were collected, after discarding 1125 duplicate articles, we analyzed the titles and abstracts of 1791 studies. There were 459 articles that met the inclusion criteria and whose text was read. A total of 23 studies were included in the final analysis. Sample sizes ranged from 6 to 206 participants. In patients with spondyloarthritis, a large majority of studies reported an increase in intestinal permeability regardless of the method used. No increase in intestinal permeability was found in RA patients compared to healthy subject in half of the studies. NSAID treatment does not appear to influence intestinal permeability in SpA and seems to increase the intestinal permeability in RA patients as much as in healthy subjects.

CONCLUSION

The results of our review suggest the existence of increased intestinal permeability in SpA patients even in the absence of NSAIDs use and regardless of the method assessing the intestinal permeability. Studies in RA patients are more controversial.

Dendritic Cells of Mesenteric and Regional Lymph Nodes Contribute to Yersinia enterocolitica O:3-Induced Reactive Arthritis in TNFRp55-/- Mice

Dendritic cells (DCs) participate in the pathogenesis of several diseases. We investigated DCs and the connection between mucosa and joints in a murine model of Yersinia enterocolitica O:3-induced reactive arthritis (ReA) in TNFRp55^-/- mice. DCs of mesenteric lymph nodes (MLN) and joint regional lymph nodes (RLN) were analyzed in TNFRp55^-/- and wild-type mice. On day 14 after Y. enterocolitica infection (arthritis onset), we found that under TNFRp55 deficiency, migratory (MHC^highCD11c⁺) DCs increased significantly in RLN. Within these RLN, resident (MHC^intCD11c⁺) DCs increased on days 14 and 21. Similar changes in both migratory and resident DCs were also detected on day 14 in MLN of TNFRp55^-/- mice. In vitro, LPS-stimulated migratory TNFRp55^-/- DCs of MLN increased IL-12/23p40 compared with wild-type mice. In addition, TNFRp55^-/- bone marrow-derived DCs in a TNFRp55^-/- MLN microenvironment exhibited higher expression of CCR7 after Y. enterocolitica infection. The major intestinal DC subsets (CD103⁺CD11b^-, CD103^-CD11b⁺, and CD103⁺CD11b⁺) were found in the RLN of Y. enterocolitica-infected TNFRp55^-/- mice. Fingolimod (FTY720) treatment of Y. enterocolitica-infected mice reduced the CD11b^- subset of migratory DCs in RLN of TNFRp55^-/- mice and significantly suppressed the severity of ReA in these mice. This result was associated with decreased articular IL-12/23p40 and IFN-γ levels. In vitro FTY720 treatment downregulated CCR7 on Y. enterocolitica-infected bone marrow-derived DCs and purified MLN DCs, which may explain the mechanism underlying the impairment of DCs in RLN induced by FTY720. Taken together, data indicate the migration of intestinal DCs to RLN and the contribution of these cells in the immunopathogenesis of ReA, which may provide evidence for controlling this disease.

Analysis of Safety, Medical Resource Utilization, and Treatment Costs by Drug Class for Management of Inflammatory Bowel Disease in the United States Based on Insurance Claims Data

INTRODUCTION

Conventional pharmaceutical interventions for inflammatory bowel disease (IBD) provide limited disease/symptom control and are associated with an increased risk of adverse events (AEs). These limitations increase patient morbidity, medical resource utilization (MRU), and costs.

METHODS

The IQVIA™ Real-World Data Adjudicated Claims-US database was leveraged to identify adult patients (> 18 years) with Crohn's disease (Crohn's) or ulcerative colitis (UC), who were new and chronic users (≥ 60 days) of oral corticosteroids (OCS), immunosuppressants (IS), anti-tumor necrosis factor agents (anti-TNF) or combinations thereof. Using aminosalicylate-treated patients as a reference, we compared AE incidence, MRU, and medical costs across drug classes.

RESULTS

The analysis included 30,676 patients (Crohn's: n = 14,528; UC: n  = 16,148). OCS monotherapy was the strongest predictor of any AE occurring [Crohn's: hazard ratio 1.62 (1.51-1.73); UC: hazard ratio 1.57 (1.49-1.66)]. A similar pattern was observed for severe infection and bone-related conditions. Patients with UC or Crohn's receiving OCS or IS plus OCS were more likely to have emergency department visits, IBD-related hospitalizations/visits/procedures, and gastrointestinal surgery than were patients receiving other therapies. Annualized total medical costs (pharmacy plus hospital service costs) were greatest for anti-TNF plus IS or anti-TNF therapy in both Crohn's and UC. Annualized medical service costs (excluding IBD drug costs) were highest for patients initiating OCS-containing therapies [Crohn's: OCS, $27,041 (24,882-29,200) and OCS plus IS, $23,332 (19,889-26,775); UC: OCS, $19,659 (17,977-21,340)].

CONCLUSION

Although biologic therapies have higher pharmacy costs, treatment decisions should consider the increased AE risks and long-term MRU costs associated with chronic use of OCS-containing therapies.

FUNDING

This study was funded by F. Hoffmann-La Roche Ltd. The journal's Rapid Service Fee and Open Access publication were paid for by ApotheCom on behalf of Genentech, a member of the Roche group who funded the study.

Effect of Gut Involvement in Patients with High Probability of Early Spondyloarthritis: Data from the DESIR Cohort

OBJECTIVE

Inflammatory bowel disease (IBD) is a well-known extraarticular feature of spondyloarthritis (SpA). The aims of this study were to evaluate factors associated with IBD and incidence over 5 years of followup in the DESIR cohort.

METHODS

DESIR is a prospective observational cohort of patients with recent-onset inflammatory back pain suggestive of axial SpA. All available variables in the database were compared between patients with and without IBD at baseline and 5 years, and occurrence over 5 years of followup, with uni- and then multivariable analysis.

RESULTS

At baseline, of 708 patients, 35 had IBD (prevalence 4.94%, CI 95% 3.3-6.5). IBD was associated (multivariable) with history of uveitis, levels of Dickkopf-1, and tumor necrosis factor, but not with phenotypic presentation (peripheral arthritis, enthesitis, dactylitis, uveitis) or baseline serum levels of other cytokines. At 5 years, 480 patients were analyzed, 58 with IBD. IBD was associated (multivariable) with fulfillment of modified New York criteria, sick leave, Bath Ankylosing Spondylitis Disease Activity Index, and smoking. There was no association with magnetic resonance imaging scores, enthesitis, psoriasis, and bone mineral density. Twenty-three incident cases of IBD were recorded: estimated occurrence rate of 0.95/100 (95% CI 0.57-1.35) patient-years (PY). Incidence of IBD is associated (multivariable) with HLA-B27 (OR 0.36, 95% CI 0.22-0.59), fulfillment of modified New York criteria (OR 3.35, 95% CI 1.85-6.08), and familial history of IBD (OR 3.31, 95% CI 1.62-6.77).

CONCLUSION

In early SpA, IBD occurs with an incidence of 1/100 PY, and is associated with poor outcome, familial history of IBD, absence of HLA-B27, and fulfillment of modified New York criteria.

IL-17 inhibition in axial spondyloarthritis: current and future perspectives

INTRODUCTION

Interleukin (IL)-17 is a proinflammatory cytokine considered to play a significant role in the immunopathogenesis of ankylosing spondylitis (AS)/axial spondyloarthritis (axSpA) as well as of other spondyloarthritides. There is a number of substances targeting IL-17, which are at different stages of development in the axSpA indication.

AREAS COVERED

This review summarizes the current evidence on the role of IL-17 in the pathophysiology of axSpA and provided a comprehensive review of clinical and radiographic outcomes as well as of safety data from studies with IL-17A inhibitors secukinumab and ixekizumab. Ongoing studies on other IL-17 inhibitors (bimekizumab, brodalumab and BCD-085) that are being developed are also summarized.

EXPERT OPINION

The development of the IL-17 inhibitors has expanded AS treatment with effective options and confirmed the pathophysiological role of IL-17 in axSpA. IL-17 inhibition showed sufficient efficacy against signs and symptoms of the disease even after the failure of tumor necrosis factor inhibitors, being at the same time reasonably safe.

Spondyloarthritis patients with and without intestinal symptoms - searching for discriminating biomarkers

Spondyloarthritis (SpA) is often complicated with subclinical gut inflammation. This study was aimed at searching for biomarkers discriminating SpA patients with and without intestinal symptoms. A group of 29 SpA patients and 33 healthy volunteers (control) were included in the study. Based on clinical evaluation, the patient cohort was subdivided into two groups: 1) SpA accompanied by various intestinal symptoms suggesting gut inflammation (group 2, n = 14) and 2) without such complications (group 1, n = 15). Serum concentrations of interleukins (IL) (IL-10, IL-17A/F, IL-22, IL-23), tumour necrosis factor (TNF), bone-homeostasis-related factors (osteoprotegerin – OPG and Dickkopf-1 – DKK-1), and the concentrations of selected gut inflammation-associated factors (intestinal fatty acid binding protein – iFABP, claudin 3 – CLDN3 and calprotectin) in samples of sera and/or urine or stool, respectively, were measured by specific ELISA. Serum concentrations of tested factors were similar in SpA patients and control. Faecal calprotectin level was higher in patients but did not discriminate between group 1 and 2. Compared to group 1, group 2 was characterized by elevated erythrocyte sedimentation rate (ESR), higher serum CLDN3 and DKK-1 levels. In SpA patients, serum DKK-1 concentrations correlated with systemic inflammation markers (R = 0.6, p < 0.01), while serum CLDN3 was found to be an independent risk factor (OR = 4.5, p = 0.021) for the occurrence of intestinal symptoms. We conclude that in SpA patients, up-regulated circulating levels of CLDN3 seem to be related to intestinal complication, while the quantity of circulating DKK-1 reflects the intensity of systemic inflammation.

Whodunit? The Contribution of Interleukin (IL)-17/IL-22-Producing γδ T Cells, αβ T Cells, and Innate Lymphoid Cells to the Pathogenesis of Spondyloarthritis

γδ T cells, αβ T cells, and innate lymphoid cells (ILCs) are capable of producing interleukin (IL)-17A, IL-17F, and IL-22. Among these three families of lymphocytes, it is emerging that γδ T cells are, at least in rodents, the main source of these key pro-inflammatory cytokines. γδ T cells were implicated in multiple inflammatory and autoimmune diseases, including psoriasis, experimental autoimmune encephalomyelitis and uveitis, colitis, and rheumatoid arthritis. Recent findings pointed toward a central role of γδ T cells in the pathogenesis of spondyloarthritis (SpA), a group of inflammatory rheumatic diseases affecting the axial skeleton. SpA primarily manifests as inflammation and new bone formation at the entheses, which are connecting tendons or ligaments with bone. In SpA patients, joint inflammation is frequently accompanied by extra-articular manifestations, such as inflammatory bowel disease or psoriasis. In humans, genome-wide association studies could link the IL-23/IL-17 cytokine axis to SpA. Accordingly, antibodies targeting IL-23/IL-17 for SpA treatment already showed promising results in clinical studies. However, the contribution of IL-17-producing γδ T cells to SpA pathogenesis is certainly not an open-and-shut case. Indeed, the cell types that are chiefly involved in local inflammation in human SpA still remain largely unclear. Some studies focusing on blood or synovium from SpA patients reported augmented IL-17-producing and IL-23 receptor-expressing γδ T cells, but other cell types might contribute as well. Here, we summarize the current understanding of how γδ T cells, αβ T cells, and ILCs contribute to the pathogenesis of human and experimental SpA.

Anti-CD74 antibodies have no diagnostic value in early axial spondyloarthritis: data from the spondyloarthritis caught early (SPACE) cohort

BACKGROUND

Anti-CD74 IgG antibodies are reported to be elevated in patients with axial spondyloarthritis (axSpA). This study assessed the diagnostic value of anti-CD74 antibodies in patients with early axSpA.

METHODS

Anti-CD74 IgG and IgA antibodies were first measured in an exploratory cohort of patients with radiographic axSpA (138 patients with ankylosing spondyloarthritis (AS)) and 57 healthy controls and then were measured in patients with early axSpA (n = 274) and with non-SpA chronic back pain (CBP) (n = 319), participating in the spondyloarthritis caught early (SPACE) prospective cohort study of patients under 45 years old with early back pain (for ≥ 3 months, but ≤ 2 years).

RESULTS

In the exploratory cohort, anti-CD74 IgG antibodies were present in 79.7% of patients with AS vs. 43.9% of healthy controls (p < 0.001). Anti-CD74 IgA antibodies were present in 28.5% of patients with AS vs. 5.3% of healthy controls (p < 0.001). In the SPACE cohort, anti-CD74 IgG antibody levels were present in 46.4% of the patients with axSpA vs. 47.9% of the patients with CBP (p = 0.71). Anti-CD74 IgA antibodies were present in 54.7% of the patients with axSpA and 37.0% of the patients with CBP (p < 0.001). This resulted in a positive predictive value of 58.8% (compared to a prior probability of 46.2%) and a negative predictive value of 59.1% (compared to a prior probability of 53.8%). In a regression model, total serum IgA was associated with axSpA odds ratio (OR) 1.19, p < 0.001) whereas anti-CD74 IgA was not (OR) 1.01, p = 0.33). Furthermore, anti-CD74 IgA was associated with sacroiliitis on magnetic resonance imaging (MRI) (OR) = 2.50, p = 0.005) and heel enthesitis (OR) = 2.56, p = 0.002).

CONCLUSIONS

Albeit anti-CD74 IgA is elevated in patients with early axSpA, this elevation is not sufficiently specific to yield significant diagnostic value in patients under 45 years old presenting with early back pain.

Cytokines and integrins related to inflammation of joint and gut in patients with spondyloarthritis and inflammatory bowel disease

Objectives

Inflammatory bowel disease (IBD) and spondyloarthritis (SpA) have some overlapping clinical features, i.e. gut and joint inflammation. Cytokines of interleukin 17(IL-17)/IL-23 axis play a pathogenic role in both diseases. Integrins (ITGs) regulate migration of immune cells to inflamed tissues (ITGβ7 into gut, ITGβ2 into gut and also to other tissues). In this study, we search for differences in the serum concentrations of these cytokines and integrins between patients suffering from SpA or IBD with and without overlapping symptoms.

Material and methods

Patients with SpA (n = 30), IBD (n = 68), and healthy volunteers (n = 28) were included in the study. Fourteen SpA patients reported symptoms characteristic for IBD. Spondyloarthritis symptoms were diagnosed in 50% of IBD patients, while other patients of this group reported arthralgia only. Serum concentrations of IL-17, IL-22, IL-23, ITGβ2, and ITGβ7 were measured by specific enzyme-linked immunosorbent assay using commercially available sets. The Mann-Whitney and Spearman’s rank tests were used for intergroup comparison and correlation assessment, respectively.

Results

Comparison of patient groups showed significantly higher serum concentrations of IL-17, IL-22, and ITGβ7 in SpA, and up-regulated levels of IL-23 in IBD patients. Similar differences were observed between patient subgroups, both with and without overlapping symptoms. In SpA but not in IBD patients, serum concentrations of ITGβ7 inversely correlated (r = –0.552) with C-reactive protein.

Conclusions

Patients with SpA and IBD differ in the circulating concentrations of IL-17/IL-23 axis cytokines and ITGβ7, irrespectively of the presence or absence of overlapping symptoms. Therefore, we conclude that observed differences are attributed rather to underlying than concurrent disease.