The paradoxical effects of TNF inhibitors on bone mineral density and radiographic progression in patients with ankylosing spondylitis

Treatment of ankylosing spondylitis with TNFα inhibitors does not affect serum levels of tryptophan metabolites

The imbalance between the kynurenine and serotonin pathways can have serious consequences, e.g., depression. One of the factors leading to the imbalance between the pathways of tryptophan metabolism is inflammation. The aim of our study was to assess the impact of treatment with tumor necrosis factor-alpha (TNFα)-inhibitors on tryptophan metabolism in patients with ankylosing spondylitis (AS). Forty patients with AS (twenty-eight males, twelve females; mean age 40 ± 11 years), qualified to receive anti-TNF-α treatment, were prospectively assessed. As a control group, 20 healthy volunteers (7 males and 13 females, mean age 38 ± 5 years) were recruited from the general population. Patients underwent full clinical and biochemical assessment before and after 6 months of therapy. Disease activity was assessed by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). The presence of depressive disorders was assessed with Beck's Depression Inventory (BDI) scale. Serum concentrations of tryptophan, serotonin, kynurenine, and quinolinic acid were measured. The predominance of the kynurenine pathway in AS patients (compared to the control group) was demonstrated (p < 0.001). Surprisingly, no significant changes in serum levels of tryptophan and its metabolites in AS patients after treatment were found, despite clinical improvement. Moreover, the components of tryptophan metabolism did not correlate significantly with the clinical activity of AS, depression nor laboratory inflammatory markers. Probably some other factors influence the pathways of tryptophan metabolism in patients with ankylosing spondylitis.

Insights into the Role of Macrophage Polarization in the Pathogenesis of Osteoporosis

Millions of people worldwide suffer from osteoporosis, which causes bone fragility and increases the risk of fractures. Osteoporosis is closely related to the inhibition of osteogenesis and the enhancement of osteoclastogenesis. In addition, chronic inflammation and macrophage polarization may contribute to osteoporosis as well. Macrophages, crucial to inflammatory responses, display different phenotypes under the control of microenvironment. There are two major phenotypes, classically activated macrophages (M1) and alternatively activated macrophages (M2). Generally, M1 macrophages mainly lead to bone resorption, while M2 macrophages result in osteogenesis. M1/M2 ratio reflects the "fluid" state of macrophage polarization, and the imbalance of M1/M2 ratio may cause disease such as osteoporosis. Additionally, antioxidant drugs, such as melatonin, are applied to change the state of macrophage polarization and to treat osteoporosis. In this review, we introduce the mechanisms of macrophage polarization-mediated bone resorption and bone formation and the contribution to the clinical strategies of osteoporosis treatment.

Bone Involvement in Patients with Spondyloarthropathies

Spondyloarthropathies (SpA) are common systemic inflammatory rheumatic diseases, in which, as in other rheumatic diseases, levels of markers of bone resorption are elevated, leading to bone loss and elevated risk of vertebral fractures. However, the diseases are also associated with new bone formation in the spine, the so-called syndesmophytes. We tried to unravel the pathogenesis of formation and growth of syndesmophytes and evaluated new diagnostic and treatment options. After a successful meeting of the Working Group on Rheumatic Diseases at the ECTS 2020, we (WL and CR) were excited about the quality of the speakers (CM, JH, AG, and GL) and their complimentary lectures. Given the relative lack of reviews on spondyloarthropathies and bone, we decided to work together on a comprehensive review that might be interesting for basic scientists and clinically relevant for clinicians. Radiographic progression in axSpA is linked to several risk factors, like male sex, smoking, HLA-B-27, increased levels of CRP, presence of syndesmophytes, and marked inflammation on MRI. The potential role of mechanical stress in the context of physically demanding jobs has been also suggested to promote structural damages. Different treatment options from NSAIDs to biologic agents like TNF inhibitors (TNFi) or IL-17inhibitors (IL-17i) result in a reduction of inflammation and symptoms. However, all these different treatment options failed to show clear and reproducible results on inhibition on syndesmophyte formation. The majority of data are available on TNFi, and some studies suggested an effect in subgroups of patients with ankylosing spondylitis. Less information is available on NSAIDs and IL-17i. Since IL-17i have been introduced quite recently, more studies are expected. IL-17 inhibitors (Il-17i) potently reduce signs and symptoms, but serum level of IL-17 is not elevated, therefore, IL-17 probably has mainly a local effect. The failure of anti-IL-23 in axSpA suggests that IL-17A production could be independent from IL-23. It may be upregulated by TNFα, resulting in lower expression of DKK1 and RANKL and an increase in osteogenesis. In active AS markers of bone resorption are increased, while bone formation markers can be increased or decreased. Bone Turnover markers and additional markers related to Wnt such as DKK1, sclerostin, and RANKL are valuable for elucidating bone metabolism on a group level and they are not (yet) able to predict individual patient outcomes. The gold standard for detection of structural lesions in clinical practice is the use of conventional radiographics. However, the resolution is low compared to the change over time and the interval for detecting changes are 2 years or more. Modern techniques offer substantial advantages such as the early detection of bone marrow edema with MRI, the fivefold increased detection rate of new or growing syndesmophytes with low-dose CT, and the decrease in 18F-fluoride uptake during treatment with TNFα-inhibitors (TNFi) in a pilot study in 12 AS patients. Detection of bone involvement by new techniques, such as low-dose CT, MRI and 18-Fluoride PET-scans, and bone turnover markers, in combination with focusing on high-risk groups such as patients with early disease, elevated CRP, syndesmophytes at baseline, male patients and patients with HLA-B27 + are promising options for the near future. However, for optimal prevention of formation of syndesmophytes we need more detailed insight in the pathogenesis of bone formation in axSpA and probably more targeted therapies.

Biological DMARDs and disease modification in axial spondyloarthritis: a review through the lens of causal inference

Axial spondyloarthritis (axSpA) is a chronic rheumatic disease characterised by inflammation predominantly involving the spine and the sacroiliac joints. In some patients, axial inflammation leads to irreversible structural damage that in the spine is usually quantified by the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). Available therapeutic options include biological disease-modifying antirheumatic drugs (bDMARDs), which have been proven effective in suppressing inflammation in several randomised controlled trials (RCT), the gold standard for evaluating causal treatment effects. RCTs are, however, unfeasible for testing structural effects in axSpA mainly due to the low sensitivity to change of the mSASSS. The available literature therefore mainly includes observational research, which poses serious challenges to the determination of causality. Here, we review the studies testing the effect of bDMARDs on spinal radiographic progression, making use of the principles of causal inference. By exploring the assumptions of causality under counterfactual reasoning (exchangeability, positivity and consistency), we distinguish between studies that likely have reported confounded treatment effects and studies that, on the basis of their design, have more likely reported causal treatment effects. We conclude that bDMARDs might, indirectly, interfere with spinal radiographic progression in axSpA by their effect on inflammation. Innovations in imaging are expected, so that placebo-controlled trials can in the future become a reality. In the meantime, causal inference analysis using observational data may contribute to a better understanding of whether disease modification is possible in axSpA.

A 2-year longitudinal study of bone health in adolescent patients with axial spondyloarthritis

PURPOSE

Axial spondyloarthritis (axSpA) is a chronic inflammatory disease that primarily affects the axial skeleton and typically has an early onset. Although earlier onset is associated with worse prognosis, there have been few studies of bone mineral density (BMD) in adolescent patients with axSpA.

METHODS

We analysed the clinical characteristics of 43 adolescent patients with axSpA at a baseline assessment and at a follow-up 2 years later. The baseline assessment included age, disease duration, treatment agents, and clinical, radiologic, and laboratory data. BMD of the lumbar spine, femoral neck, and total hip were measured by dual-energy X-ray absorptiometry during both the baseline assessment and the 2-year follow-up. We performed multivariate linear regression analyses to identify factors independently associated with BMD. We analysed the associations between changes in BMD and reductions in inflammatory markers.

RESULTS

The average age of participants was 17.9 years and the mean disease duration was 2.2 years. Of the 43 patients, 10 (23%) had low BMD at any site (lumbar spine, femoral neck, and/or total hip). At baseline, multivariate analysis showed that body mass index (BMI), erythrocyte sedimentation rate (ESR), and spinal structural damage were associated with lumbar spine Z-scores. Increases in BMD in the lumbar spine were correlated with reductions in ESR (r = 0.40, P = 0.02) and C-reactive protein (CRP) (r = 0.40, P = 0.02). Increases in BMD in the total hip were correlated with reductions in CRP (r = 0.38, P = 0.03).

CONCLUSION

In adolescent axSpA patients, bone health was associated with systemic inflammation and the severity of structural damage. Reduced systemic inflammation was associated with improvements in bone health.

Prevalence and factors associated with osteoporosis and bone mineral density testing in psoriatic arthritis

OBJECTIVES

To determine bone mineral density (BMD) in psoriatic arthritis (PsA) patients, factors associated with undergoing BMD testing, and the effect of PsA clinical activity on BMD.

METHODS

Patients attending the University of Toronto PsA Clinic with a BMD from cohort inception to January 2019 were included. Descriptive statistics summarized lumbar spine, femoral neck and total hip T-scores. Cox proportional hazard regression identified predictors for BMD testing. Logistic regression analysis determined odds of having normal (T-score ≥ -1.0) versus osteoporotic range BMD (T-score ≤ -2.5). A multi-state model determined factors associated with BMD state changes over time.

RESULTS

Of the 1479 patients, 214 had BMDs. Mean T-scores at the lumbar spine, femoral neck and total hip were -0.30±0.32, -1.10±1.04 and -0.45±0.42 respectively. Osteopenia and osteoporosis occurred in 45.27% and 12.94% of patients. Increasing age, menopause, elevated acute phase reactants, biologic, methotrexate and systemic glucocorticoid use were associated with a higher chance of undergoing BMD testing. Increased BMI and biologic use were associated with a lower chance of having osteoporotic range BMD. In multi-state analysis, polyarthritis may portend lower BMDs over time, although this did not achieve statistical significance due to low patient numbers.

CONCLUSIONS

The prevalence of osteopenia and osteoporosis in the PsA cohort were similar to the general population. Clinicians are using osteoporosis risk factors and PsA disease severity markers to select patients for BMD testing. Polyarticular disease may portend worse BMDs. Biologic use and increased BMI appear to have a protective effect.

Loss and gain of bone in spondyloarthritis: what drives these opposing clinical features?

The breadth of bone lesion types seen in spondyloarthritis is unprecedented in medicine and includes increased bone turnover, bone loss and fragility, osteitis, osteolysis and erosion, osteosclerosis, osteoproliferation of soft tissues adjacent to bone and spinal skeletal structure weakness. Remarkably, these effects can be present simultaneously in the same patient. The search for a potential unifying cause of effects on the skeleton necessarily focuses on inflammation arising from the dysregulation of immune response to microorganisms, particularly dysregulation of T_H17 lymphocytes, and the dysbiosis of established gut and other microbiota. The compelling notion that a common antecedent pathological mechanism affects existing bone and tissues with bone-forming potential (entheses), simultaneously with variable effect in the former but bone-forming in the latter, drives basic research forward and focuses our awareness on the effects on these bone mechanisms of the increasing portfolio of targeted immunotherapies used in the clinic.

Pharmacological treatment for managing bone health in axial spondyloarthropathy: systematic review and meta-analysis

Axial spondyloarthropathy (axSpA) is associated with an increased prevalence of osteoporosis, but no recommendations exist to guide management. This systematic review and meta-analysis aim to assess the efficacy of pharmacological and non-pharmacological interventions on bone mineral density (BMD) in axSpA. Electronic databases were searched from inception to June 2019 for randomised controlled trials (RCTs) and quasi (q)-RCTs with pharmacological and non-pharmacological interventions. Independent reviewers undertook screening, and risk of bias and quality assessments. Primary outcomes of interest were BMD at spine and hip. Eight studies (two RCTs and six qRCTs) were included (602 participants). Moderate level evidence favoured alendronate over placebo at femoral neck [mean difference (MD) 2.01, 95% CI 0.67 to 3.35], but there was low-level evidence showing no effect at the spine. There was moderate level evidence showing no effect of tumour necrosis factor inhibitors (TNFi) on BMD at total hip (MD - 0.01, 95% CI - 0.06 to 0.04). Very low-level evidence demonstrated no effect of TNFi on spine or femoral neck. Moderate level evidence favoured neridronate over infliximab at the spine (MD 3.26, 95% CI 1.14 to 5.38), but low-level evidence showed no effect at the total hip (MD 2.75, 95% CI - 0.21 to 5.71). There were no eligible studies investigating the efficacy of non-pharmacological interventions. We conditionally recommend alendronate for management of low BMD in axSpA. The balance of evidence does not recommend the use of TNF-inhibitors for treating low BMD. There is a lack of high-quality evidence guiding clinicians treating osteoporosis in axSpA.

Effect of Therapy on Radiographic Progression in Axial Spondyloarthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

To investigate the effect of therapies on radiographic progression in patients with axial spondyloarthritis (SpA).

METHODS

A comprehensive database search for studies assessing radiographic progression in axial SpA (particular treatment versus no treatment of interest) was performed. Study-specific standardized mean differences in treatment outcomes at 2 and ≥4 years were estimated and combined using random-effects models.

RESULTS

Twenty-four studies in patients with axial SpA were identified, of which 18 involved tumor necrosis factor inhibitors (TNFi), 8 involved nonsteroidal antiinflammatory drugs (NSAIDs), and 1 involved secukinumab. Spinal radiographic progression, as measured by the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS), was not significantly different between TNFi-treated and biologics-naive patients at 2 years (mSASSS difference -0.73 [95% confidence interval (95% CI) -1.52, 0.12], I2 = 28%) and ≥4 years (mSASSS difference -2.03 [95% CI -4.63, 0.72], I2 = 63%). Sensitivity analyses restricted to studies with a low risk of bias showed a significant difference in spinal radiographic progression between TNFi-treated and biologics-naive patients at ≥4 years (mSASSS difference -2.17 [95% CI -4.19, -0.15]). No significant difference in spinal radiographic progression was observed between NSAID-treated and control patients (mSASSS difference -0.30 [95% CI -2.62, 1.31], I2 = 71%) or between secukinumab-treated and biologics-naive patients (mSASSS difference -0.34 [95% CI -0.85, 0.17]). With regard to treatment differences in patients with nonradiographic axial SpA or in patients with radiographic progression measured using the sacroiliac joint score, an insufficient number of studies were available for analysis.

CONCLUSION

Although no significant protective effect of TNFi treatment on spinal radiographic progression was seen over the course of 2 years or ≥4 years in patients with axial SpA, our analysis restricted to studies with a low risk of bias showed a protective effect of TNFi after ≥4 years. Therefore, long-term TNFi exposure might confer beneficial effects on spinal radiographic progression in axial SpA. No difference in radiographic progression at 2 years was seen in either the NSAID or secukinumab treatment groups compared to their controls. Future studies should explore the effects of biologic treatment on radiographic progression, as well as the effects of long-term biologics exposure, in patients with early axial SpA or those with nonradiographic axial SpA.

The effect of tumour necrosis factor inhibitors on radiographic progression in axial spondyloarthritis: a systematic literature review

The effect of TNF-α inhibitors (TNFi), with or without concomitant NSAIDs, on radiographic progression in axial SpA remains unclear. Therefore, we performed a systematic literature review up to January 2019 to determine whether longer use of standard dose TNFi is superior vs lower duration or lower dose TNFi therapy, conventional synthetic DMARDs alone, or no therapy in inhibiting radiographic progression in patients with axial SpA. Our search yielded 373 titles of which 14 full text articles and five abstracts were eligible for quantitative analysis. Studies had an overall moderate to critical risk of bias. Data could not be pooled due to clinical and methodological heterogeneity. Individual studies showed conflicting results with mainly no significant difference in radiographic progression when comparing effect of TNFi therapy to no TNFi therapy or when comparing to less TNFi therapy until 2 years of follow-up. Results that are more significant are shown after 2 years’ follow-up, mainly in subgroups with baseline syndesmophytes. Data on the additional or synergistic effect of concomitant NSAID use were inconclusive.

Long-Term Treatment With TNF-Alpha Inhibitors Improves Bone Mineral Density But Not Vertebral Fracture Progression in Ankylosing Spondylitis

The aim of this cohort study was to evaluate the long-term effects of TNF inhibitors (TNFis) on BMD and the incidence of vertebral fractures (VFxs) in patients with ankylosing spondylitis (AS). Consecutive patients with active AS with TNFi treatment duration up to 4 years with available DXA scans and spine X-rays were included. BMD (classified according to the WHO criteria for osteoporosis) of the hip and lumbar spine, the VFx (classified as a Genant score >1/>20% height loss), and radiological progression (modified stoke ankylosing spondylitis spinal score [mSASSS]) scores were obtained at baseline and at 4 years of TNFi treatment. Overall, 135 AS patients were included. At baseline, 40.1% of patients had low BMD of the hip and 40.2% of the lumbar spine. This decreased to 38.1% (p = 0.03) with low hip BMD and 25.3% (p < 0.001) of the lumbar spine BMD after 4 years of TNFi treatment. VFxs were present at baseline in 11.1% of the 131 patients, which increased to 19.6% after 4 years of TNFi treatment. A Genant score ≥2, was found at baseline in 3 out of 14 VFx (21.4%) patients, which increased to 7 out of 27 VFx (25.9%) patients after 4 years. All disease activity parameters-the ankylosing spondylitis disease activity scale, the C-reactive protein, the erythrocyte sedimentation rate, and the bath ankylosing spondylitis disease activity index-decreased significantly (p < 0.001). The mean radiological progression (n = 80) increased significantly from a median mSASSS of 4.0 (1.5 to 16.0) at baseline to 6.5 (2.1 to 22.9) after 4 years of TNFi treatment (p < 0.001). Despite the improvement in BMD and the decrease in disease activity, we still found new VFxs, an increase in severity in the number and grade of VFxs, and radiographic progression during 4 years of treatment with TNFis in AS patients with long disease duration. © 2019 American Society for Bone and Mineral Research.

Effect of anti-tumor necrosis factor α treatment on radiographic progression in patient with ankylosing spondylitis: A systematic review and meta-analysis

BACKGROUND

Efficacy of anti-tumor necrosis factor (anti-TNF)α treatment in patient with active ankylosing spondylitis (AS) had been proved by many clinical studies. Inflammation and new bone formation in spine were two pivotal aspects in AS. TNF α inhibitor could eliminate inflammation including clinical and laboratory inflammatory manifestation. Paradoxical results whether TNF α antagonist could delay radiographic progression in AS were often been reported simultaneously.

OBJECTIVES

To review the literature about the effect of TNF α inhibitor on radiographic progression and disease activity in patient with AS.

METHODS

We conducted a comprehensive search including Medline, EMBASE and the Cochrane Library from 1 January 2000 to 15 August 2017. Two reviewers independently supplemented with hand searching for the reference lists of inclusion. All trials focusing on radiographic progression or disease activity in patients with AS treated with anti-TNF α agents. Primary outcomes were modified Stokes AS Spinal Score (mSASSS), as well as Bath AS disease activity index (BASDAI) and Bath AS functional index (BASFI). Two reviewers independently selected studies and analyzed data. Methodological quality was assessed using the Newcastle-Ottawa scale (NOS). We pooled effects recorded on different scales as Standardized mean differences (SMDs) with 95% confidence intervals (CIs) using random-effects models.

RESULTS

We included 14 studies of low to moderate risk of bias with 3,186 patients, compared with control group, there was no effect of mSASSS changes (SMD = -0.12, 95% CI: -1.17-0.93, p value = .82, I² = 95%) and follow-up (SMD = 0.03, 95% CI: 0.21-0.26, p value = .82, I² = 36%) estimation in anti-TNF α group. However anti-TNF α agent treatment led to remarkable improvements on both Bath AS disease activity index (BASDAI) (SMD = 1.06, 95% CI: 0.22-1.89, p value = .01, I² = 96%) and Bath AS functional index (BASFI) (SMD = 0.93, 95% CI: 0.24-1.92, p value = .01, I² = 97%) scores at 12 weeks.

CONCLUSION

Our meta-analysis found no significant effect on delaying radiographic progression in AS treated with TNF α inhibitor, although TNF α inhibitor could do improve significantly disease activity and physical function in AS.

Cortical bone loss is an early feature of nonradiographic axial spondyloarthritis

Background

In the present study, we investigated bone geometry, microstructure, and volumetric bone mineral density (vBMD) in a cohort of patients with nonradiographic axial spondyloarthritis (nr-axSpA) in order to define the early bone changes occurring in axial spondyloarthritis (axSpA) and to define potential factors for deterioration of bone microstructure.

Methods

Patients with axSpA (n = 107) and healthy control subjects (n = 50) of similar age and sex were assessed for geometric, volumetric, and microstructural parameters of bone using high-resolution peripheral quantitative computed tomography (HR-pQCT) at the radius. Additionally, demographic and disease-specific characteristics of patients with axSpA were recorded.

Results

Patients with nr-axSpA and control subjects were comparable in age, sex, and body mass index. Geometric and microstructural analysis by HR-pQCT revealed a significantly reduced cortical area (p = 0.022) and cortical thickness (p = 0.006) in patients with nr-axSpA compared with control subjects. Total and cortical vBMD were significantly reduced in patients with nr-axSpA (p = 0.042 and p = 0.007, respectively), whereas there was no difference in trabecular vBMD. Patients with a short disease duration (< 2 years; n = 46) also showed significant reduction of cortical thickness and cortical area compared with control subjects. Patients with disease duration > 2 years (n = 55) additionally developed a decrease of cortical and total vBMD. Multiple regression models identified male sex to be associated with lower cortical vBMD and female sex to be associated with lower trabecular vBMD.

Conclusions

Bone microstructure in patients with nr-axSpA is characterized primarily by deterioration of cortical bone. Cortical bone loss starts early and is evident within the first 2 years of the disease.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1620-1) contains supplementary material, which is available to authorized users.

Osteoporosis in psoriatic arthritis: a cross-sectional study of an outpatient clinic population

Background

The risk of osteoporosis in patients with psoriatic arthritis (PsA) still remains unclear. The aim of this study was to investigate bone mineral density (BMD) at the hip and lumbar spine measured by dual-energy X-ray absorptiometry in patients with PsA.

Methods

From an outpatient clinic in southern Norway, 140 patients with PsA were consecutively recruited and assessed for osteoporosis as part of a prospective study from January 2013 to May 2014. An extensive data collection was performed including demographic data and measures reflecting disease activity and health status.

Results

Mean age was 52.4 years and 71 (50.7%) were women. Median disease duration was 7.8 years. The proportion of patients with low BMD (defined as Z score≤-1.0 SD) was comparable to the expected value of 16%, according to the normal distribution of the Z score in the population. Osteoporosis was only found in 6.4% (95% CI3% to 11%) of the patients. No significant associations were found between BMD and disease activity measures.

Conclusion

The prevalence of PsA patients with osteoporosis or low BMD was low and in the range seen in the reference population. This supports that patients with PsA are not at high risk for osteoporosis compared with the general population. Therefore, clinicians may follow the general population guidelines for monitoring of osteoporosis for patients with PsA.

Role of Stem Cells in Pathophysiology and Therapy of Spondyloarthropathies-New Therapeutic Possibilities?

Considerable progress has been made recently in understanding the complex pathogenesis and treatment of spondyloarthropathies (SpA). Currently, along with traditional disease modifying anti-rheumatic drugs (DMARDs), TNF-α, IL-12/23 and IL-17 are available for treatment of such diseases as ankylosing spondylitis (AS) and psoriatic arthritis (PsA). Although they adequately control inflammatory symptoms, they do not affect the abnormal bone formation processes associated with SpA. However, the traditional therapeutic approach does not cover the regenerative treatment of damaged tissues. In this regards, stem cells may offer a promising, safe and effective therapeutic option. The aim of this paper is to present the role of mesenchymal stromal cells (MSC) in pathogenesis of SpA and to highlight the opportunities for using stem cells in regenerative processes and in the treatment of inflammatory changes in articular structures.

M2 polarization of monocytes in ankylosing spondylitis and relationship with inflammation and structural damage

The aim of this study was to evaluate the polarization of peripheral blood monocytes in the patients with ankylosing spondylitis (AS) and to determine the correlations between monocyte polarization and inflammation and structural damage. A total of 120 AS patients, 50 rheumatoid arthritis (RA) patients and 100 healthy controls were enrolled in the study. M1 (CD68+CD192+) and M2 (CX3CR1+CD163+) monocytes were characterized by flow cytometry. Demographic, clinical, radiographic and laboratory data were collected and analyzed. A large increase in M2 (CX3CR1+CD163+) monocytes was observed in AS, and M2/M1 ratio was 7.18 ± 6.12, 2.54 ± 3.14 and 35.61 ± 20.04 in control, RA and AS, respectively. The M2/M1 ratio correlated with modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) (r = 0.565; p < 0.001), ESR (r = -0.321; p < 0.001, CRP (r = -0.265; p < 0.001) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) (r = -0.201; p = 0.028). Anti-TNF-α therapy induced a significant reduction in the percentage of M1 monocyte, ESR, CRP and BASDAI in AS patients. The present results demonstrated that M2 type polarized monocytes are predominant in the peripheral blood in AS and the M2/M1 ratio is correlated with structural damage (mSASSS), inflammatory biomarkers (ESR and CRP) and BASDAI.

Osteoporosis Management in Ankylosing Spondylitis

Low bone mineral density (BMD) is increasingly recognized as a common comorbid condition in ankylosing spondylitis (AS). As low BMD increases fracture risk, it is important to identify and treat low BMD in patients with AS who have been shown to be at increased risk for fractures above the population normal. Since low BMD occurs early in disease, we screen during the first year of diagnosis with dual energy x-ray absorptiometry (DXA). If patients are found to have osteoporosis by T-score of less than -2.5 or if their Z-score on DXA is more than two standard deviations below the mean, we initiate therapy with bisphosphonates in males and in females who are not planning any future pregnancies. While reduction in fracture risk with bisphosphonate therapy has not been clearly defined in patients with AS, reduction in vertebral and hip fractures has been well established in primary osteoporosis and thus it is our first line treatment. If there are contraindications to the use of bisphosphonates in the treatment of low BMD, we will consider the use of denosumab. If the patient is not receiving a TNF-alpha inhibitor (TNFi) and has active disease, we also favor early initiation of TNFi due to their positive effects on BMD though the outcome on reduction in vertebral fractures remains unclear. We counsel all patients regarding the importance of adequate intake of vitamin D and calcium per the Institute of Medicine guidelines. All patients should be encouraged to participate in weight-bearing activities with a focus on core strength and gait training.

Alteration of Bone Turnover Markers in Canonical Wingless Pathway in Patients With Ankylosing Spondylitis

Objectives

This study aims to determine the levels of bone turnover markers in canonical wingless pathway in patients with ankylosing spondylitis (AS) and the correlation with disease activity indexes.

Patients and methods

We recruited a total of 43 AS patients (34 males, 8 females; mean age 36.8±9.3 years; range 22 to 62 years) and age- and sex-matched 42 healthy controls (32 males, 10 females; mean age 36.1±9.7; range 24 to 59 years). Serum levels of components of canonical wingless pathway including Dickkopf-1, glycogen synthase kinase-3β, β-catenin, alkaline phosphatase, and osteocalcin were detected using enzyme- linked immunosorbent assay method. All patients were assessed in terms of erythrocyte sedimentation rate, C-reactive protein, Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Functional Index, Ankylosing Spondylitis Disease Activity Score, and the modified Stoke's Ankylosing Spondylitis Spine Score. Pearson's correlation test was used to analyze the correlation between serum bone turnover markers and clinical assessment indexes.

Results

No significant difference was observed between AS patients and healthy controls for the levels of glycogen synthase kinase-3β, β-catenin, alkaline phosphatase, and osteocalcin, respectively (p>0.05). The level of Dickkopf-1 was significantly higher in AS patients (1914.5±407.8 pg/mL) than in healthy controls (1729.1±352.9 pg/mL) (p<0.05). There was no correlation between high Dickkopf-1 level and any of the clinical parameters contributing to inflammation or bone formation. However, the correlation between osteocalcin and disease duration was significant in AS patients (r=0.323, p=0.034).

Conclusion

Alteration of bone turnover markers in canonical wingless pathway was observed in AS. This might partially explain the complicated mechanism of bone formation in the disease.

Decreased Serotonin Levels and Serotonin-Mediated Osteoblastic Inhibitory Signaling in Patients With Ankylosing Spondylitis

Evidence suggests that serotonin is an inhibitor of bone formation. We aimed to assess: 1) serum serotonin levels in patients with ankylosing spondylitis (AS), a prototype bone-forming disease, compared with patients with rheumatoid arthritis (RA) and healthy subjects; 2) the effect(s) of TNFα blockers on serum serotonin levels in patients with AS and RA; and 3) the effect(s) of serum of AS patients on serotonin signaling. Serum serotonin levels were measured in 47 patients with AS, 28 patients with RA, and 40 healthy subjects by radioimmunoassay; t test was used to assess differences between groups. The effect of serum on serotonin signaling was assessed using the human osteoblastic cell line Saos2, evaluating levels of phospho-CREB by Western immunoblots. Serotonin serum levels were significantly lower in patients with AS compared with healthy subjects (mean ± SEM ng/mL 122.9 ± 11.6 versus 177.4 ± 24.58, p = 0.038) and patients with RA (mean ± SEM ng/mL 244.8 ± 37.5, p = 0.0004). Patients with AS receiving TNFα blockers had significantly lower serotonin levels compared with patients with AS not on such treatment (mean ± SEM ng/mL 95.8 ± 14.9 versus 149.2 ± 16.0, p = 0.019). Serotonin serum levels were inversely correlated with pCREB induction in osteoblast-like Saos-2 cells. Serotonin levels are low in patients with AS and decrease even further during anti-TNFα treatment. Differences in serotonin levels are shown to have a functional impact on osteoblast-like Saos-2 cells. Therefore, serotonin may be involved in new bone formation in AS.

Etanercept Increases Bone Mineral Density in Ankylosing Spondylitis, but Does Not Prevent Vertebral Fractures: Results of a Prospective Observational Cohort Study

OBJECTIVE

Ankylosing spondylitis (AS) is characterized by chronic inflammation leading to ankylosis, but also to low bone mineral density (BMD) and vertebral fractures (VFx). Treatment with tumor necrosis factor-α blockers decreases inflammation and has shown to be effective in increasing BMD. We studied the effects of etanercept (ETN) on BMD and VFx in patients with AS after 2 years of treatment. Further, we studied changes in bone turnover markers and radiological damage.

METHODS

Patients with active AS, treated with ETN for 2 years, were included. BMD lumbar spine and hip were measured at baseline and after 2 years, as well as radiological damage (modified Stoke Ankylosing Spondylitis Spinal Score with the addition of the thoracic spine), VFx (Genant method), and change in bone turnover markers.

RESULTS

Forty-nine patients with AS were included. After 2 years of ETN, hip BMD increased by 2.2% (p = 0.014) and lumbar spine BMD by 7.0% (p < 0.001). The Bath Ankylosing Spondylitis Disease Activity Index decreased significantly (p < 0.001), as well as C-reactive protein and erythrocyte sedimentation rate (p < 0.001). Despite ETN therapy, the number of patients with VFx more than doubled (from 6 to 15 patients, p = 0.003). Also, the radiological damage increased significantly over time (from 12.1 to 18.5, p < 0.001); however, no significant change in bone turnover markers was found.

CONCLUSION

This prospective longitudinal observational cohort study showed that after 2 years of ETN, BMD of the hip and spine increased significantly, but the number of patients with VFx and the severity of VFx increased as well. Besides that, radiological progression, including the thoracic spine, increased significantly. Thus, the favorable bone-preserving effect is accompanied by unfavorable outcomes on VFx and radiological damage.

Effect of Tumor Necrosis Factor Inhibitor Therapy on Osteoclasts Precursors in Ankylosing Spondylitis

Introduction

Ankylosing Spondylitis (AS) is characterized by excessive local bone formation and concomitant systemic bone loss. Tumor necrosis factor (TNF) plays a central role in the inflammation of axial skeleton and enthesis of AS patients. Despite reduction of inflammation and systemic bone loss, AS patients treated with TNF inhibitors (TNFi) have ongoing local bone formation. The aim of this study was to assess the effect of TNFi in the differentiation and activity of osteoclasts (OC) in AS patients.

Methods

13 AS patients treated with TNFi were analyzed at baseline and after a minimum follow-up period of 6 months. 25 healthy donors were recruited as controls. Blood samples were collected to assess receptor activator of nuclear factor kappa-B ligand (RANKL) surface expression on circulating leukocytes and frequency and phenotype of monocyte subpopulations. Quantification of serum levels of bone turnover markers and cytokines, in vitro OC differentiation assay and qRT-PCR for OC specific genes were performed.

Results

RANKL⁺ circulating lymphocytes (B and T cells) and IL-17A, IL-23 and TGF-β levels were decreased after TNFi treatment. We found no differences in the frequency of the different monocyte subpopulations, however, we found decreased expression of CCR2 and increased expression of CD62L after TNFi treatment. OC number was reduced in patients at baseline when compared to controls. OC specific gene expression was reduced in circulating OC precursors after TNFi treatment. However, when cultured in OC differentiating conditions, OC precursors from AS TNFi-treated patients showed increased activity as compared to baseline.

Conclusion

In AS patients, TNFi treatment reduces systemic pro osteoclastogenic stimuli. However, OC precursors from AS patients exposed to TNFi therapy have increased in vitro activity in response to osteoclastogenic stimuli.

Wnt5a is expressed in spondyloarthritis and exerts opposite effects on enthesis and bone in murine organ and cell cultures

Spondyloarthritis (SpA) is a chronic inflammatory joint disorder that initiates at the enthesis, where tendons attach to bone through a fibrocartilage zone. At late stages, excessive bone apposition appears within the diseased enthesis. Because Wnt5a participates to normal bone formation and appears related to inflammatory processes, we investigated the role of this Wnt growth factor in inflammation-associated ossification in SpA. The concentration of Wnt5a assessed by enzyme-linked immunosorbent assay in synovial fluids of patients with SpA (2.58 ± 0.98 ng/mL) was higher than in osteoarthritic patients (1.33 ± 0.71 ng/mL). In murine primary cultures of tendon cells, chondrocytes, and osteoblasts and in an organotypic model of mouse ankle, we showed that tumor necrosis factor α reversibly diminished Wnt5a expression and secretion, respectively. Wnt5a decreased gene expression of differentiation markers and mineralization in cultured chondrocytes and reduced alkaline phosphatase activity in Achilles tendon enthesis (-14%) and osteocalcin protein levels released by ankle explants (-36%). On the contrary, Wnt5a stimulated ossification markers' expression in cultured osteoblasts and increased the bone volume of the tibial plateau of the cultured explants (+19%). In conclusion, our results suggest that Wnt5a is expressed locally in the joints of patients with SpA. Wnt5a appears more associated with ossification than with inflammation and tends to inhibit mineralization in chondrocytes and enthesis, whereas it seems to favor the ossification process in osteoblasts and bone. Further studies are needed to decipher the opposing effects observed locally in enthesis and systemically in bone in SpA.

Factors associated with bone mineral density loss in patients with spondyloarthropathies: A 4-year follow-up study

OBJECTIVE

To explore the relationship between laboratory, functional, disease activity markers and bone mineral density (BMD) loss in patients with spondyloarthropathies (SpAs).

METHODS

A cohort of 41 SpA patients were followed up for 4 years. Disease activity indices, spinal mobility and laboratory tests, BMD using were monitored at the baseline and 4-year follow-up. The 4% BMD loss at either of the proximal femurs was defined as significant.

RESULTS

Over the 4-year study period, 27% of SpA patients experienced femoral BMD loss. Baseline BMD>0.85g/cm(2) (p=0.011) was the baseline factor associated with BMD loss at 4-year follow-up. Several clinical and functional tests were helpful in identifying the BMD loss at follow-up: CRP>15.6mg/L (sens. 91%, spec. 70%), ESR>29mm/h (sens. 82%, spec. 73%), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI)>4.75 (sens. 91%, spec. 62%). At follow-up anti-TNFα treatment history, stable or improved lateral flexion and intermalleolar distance (NPV, accordingly, 95%, 88% and 87%), made BMD loss unlikely. Deterioration of the physician assessment of global disease activity (PAGDA) score from baseline to follow-up was a remarkable predictor of BMD loss (PPV=0.83), while stable or improved score excluded the BMD loss (NPV=0.83). According to multiple logistic regression analysis, baseline BMD value and follow-up CRP levels, when considered together, identify BMD status correctly in 85% of SpA patients (Nagelkerke R(2)=0.676).

CONCLUSION

Baseline BMD, anti-TNFα treatment, PAGDA score, spinal mobility tests and disease activity markers are useful factors in predicting the BMD loss in SpA patients and can provide surrogate information on BMD status.

Bone mass in axial spondyloarthritis: A literature review

AIM: To review the published literature reporting bone loss in patients with axial spondyloarthritis (SpA) particularly those studies using dual X-ray absorptiometry (DXA) methods.

METHODS: This literature review examines the reported bone mass in patients with ax-SpA, particularly those using the DXA methods. The MEDLINE, Web of Science and Scopus databases were searched for relevant articles published between September 1992 and November 2013. Some of used search terms were ankylosing spondylitis (AS), SpA, spondyloarthropathy, bone loss, bone mass, osteopenia, bone mineral density, osteoporosis (OP), densitometry. Studies in which bone loss was investigated by using DXA in patients with SpA were eligible. Each article was reviewed and the key elements were noted.

RESULTS: There were 286 hits on MEDLINE, 200 on Web of Science and 476 on Scopus. After applying inclusion and exclusion criteria, we identified 55 articles in our systematic search. The sample size of the studies varied from 14 to 332 patients with SpA. The reported age range varied from 25 to 56 years in the reviewed studies. The symptom duration of patients with axSpA varied from 1.6 to 49 years. There were more males than females in these studies. Most of the recruited females were premenopausal women. Reported HLA-B27 positivity changed between 19% to 95%. The prevalence of OP and osteopenia in patients with SpA varied from 3%-47% to 5%-88%, respectively, in the included studies. In particular, the prevalence of OP and osteopenia ranged from 2.0%-47.0% and 5.0%-78.3%, respectively, in patients with AS. There are conflicting results regarding the relationship among disease activity, acute phase response and bone mass. Some studies suggest good correlation of bone mass with disease activity and acute phase reactants.

CONCLUSION: Bone loss may be determined in patients with axSpA at the lumbar spine or proximal femur even in the early phase of the disease and may be associated with inflammation (bone marrow edema) at the vertebral colon.

Ankylosing spondylitis confers substantially increased risk of clinical spine fractures: a nationwide case-control study

Ankylosing spondylitis (AS) leads to osteopenia/osteoporosis and spine rigidity. We conducted a case-control study and found that AS-affected patients have a 5-fold and 50% increased risk of clinical spine and all clinical fractures, respectively. Excess risk of both is highest in the first years and warrants an early bone health assessment after diagnosis.

INTRODUCTION

Ankylosing spondylitis (AS) is related to spine rigidity and reduced bone mass, but data on its impact on fracture risk are scarce. We aimed to study the association between AS and clinical fractures using a case-control design.

METHODS

From the Danish Health Registries, we identified all subjects who sustained a fracture in the year 2000 (cases) and matched up to three controls by year of birth, gender and region. Clinically diagnosed AS was identified using International Classification of Diseases, 8th revision (ICD-8; 71249), and International Classification of Diseases, 10th revision (ICD-10; M45) codes. We also studied the impact of AS duration. Conditional logistic regression was used to estimate crude and adjusted odds ratios (ORs) for non-traumatic fractures (any site, clinical spine and non-vertebral) according to AS status and time since AS diagnosis. Multivariate models were adjusted for fracture history, socio-economic status, previous medical consultations, alcoholism and use of oral glucocorticoids.

RESULTS

We identified 139/124,655 (0.11%) AS fracture cases, compared to 271/373,962 (0.07%) AS controls. Unadjusted (age- and gender-matched) odds ratio (OR) were 1.54 [95% confidence interval (95%CI) 1.26-1.89] for any fracture, 5.42 [2.50-11.70] for spine and 1.39 [1.12-1.73] for non-vertebral fracture. The risk peaked in the first 2.5 years following AS diagnosis: OR 2.69 [1.84-3.92] for any fracture.

CONCLUSIONS

Patients with AS have a 5-fold higher risk of clinical spine fracture and a 35% increased risk of non-vertebral fracture. This excess risk peaks early, in the first 2.5 years of AS disease. Patients should be assessed for fracture risk early after AS diagnosis.

Clinical studies on bone-related outcome and the effect of TNF-α blocking therapy in ankylosing spondylitis

PURPOSE OF REVIEW

To provide an overview of clinical trials and observational studies investigating the effect of tumor necrosis factor-alpha (TNF-α) blocking therapy on bone formation and bone loss in patients with ankylosing spondylitis (AS).

RECENT FINDINGS

The effect of TNF-α blocking therapy on excessive bone formation or osteoproliferation remains inconclusive. Radiographic assessment of spinal osteoproliferation is complicated by the overall slow rate of progression and the high variability between individual AS patients. Multiple studies demonstrated that TNF-α blocking therapy results in a significant increase in bone mineral density (BMD) at the lumbar spine and hip. Based on bone turnover marker (BTM) analysis, this can mainly be explained by an increase in mineralization and decrease in bone resorption.

SUMMARY

Both osteoproliferation (e.g. syndesmophytes and ankylosis of vertebrae) and excessive bone loss resulting in osteoporosis and vertebral fractures are frequently present in AS. Previous studies showed that BMD increases during TNF-α blocking therapy. Long-term follow-up in a large cohort of patients is needed to investigate whether TNF-α blockers can consolidate or stop spinal osteoproliferation and prevent vertebral fractures. Future studies should focus on the effect of these agents on bone-related outcome in AS patients with early vs. advanced disease.

Radiographic Hip Involvement in Ankylosing Spondylitis: Factors Associated with Severe Hip Diseases

Objective.

To determine the factors associated with severe radiographic hip involvement in patients with ankylosing spondylitis (AS).

Methods.

A cross-sectional retrospective study was performed. The patients were classified into 3 groups based on the Bath Ankylosing Spondylitis Radiology Hip Index (BASRI-hip): minimal hip disease, moderate hip disease, and severe hip disease. Demographic, clinical, radiographic, and laboratory data were collected and analyzed. To identify factors associated with severe hip disease, ordinal regression analyses were performed.

Results.

A total of 256 patients were involved in the study. There were differences in the age at onset, delay in diagnosis, bilateral hip involvement, sacroiliitis, Schober’s index, and occiput-to-wall distance among the 3 groups (p < 0.05). The patients with severe hip disease had lower C-reactive protein and erythrocyte sedimentation rate levels than did the minimal group (p < 0.05). The functional status based on the Bath Ankylosing Spondylitis Functional Index and the Harris Hip Score showed significant differences (p < 0.05). The results of the ordinal regression analyses showed that bilateral hip involvement, sacroiliitis, delay in diagnosis, age at onset, and spinal involvement were associated with a higher BASRI-hip (p < 0.05).

Conclusion.

Bilateral hip involvement, severe sacroiliitis, longer delay in diagnosis, early disease onset, and spinal involvement are associated with severe hip disease in patients with AS. The severity of hip involvement is associated with the functional status in AS.

Incidence and predictors of morphometric vertebral fractures in patients with ankylosing spondylitis

Introduction

Ankylosing spondylitis (AS) is associated with an increased incidence of vertebral fractures (VFs); however the actual incidence and predictors of morphometric VFs are unknown. The present study examined the incidence and predictors of new VFs in a large AS cohort.

Methods

In total, 298 AS patients who fulfilled the modified New York criteria were enrolled and spinal radiographs were evaluated biennially. Clinical and laboratory data and radiographic progression were assessed according to the Bath AS Disease Activity Index, erythrocyte sedimentation rate, C-reactive protein (CRP), and the Stoke AS spine score (SASSS). VF was defined according to the Genant criteria. The incidence of VFs at 2 and 4 years was evaluated using the Kaplan-Meier method. The age-specific standardized prevalence ratio (SPR) for AS patients in comparison with the general population was calculated.

Results

Of 298 patients, 31 (10.8%) had previous VFs at baseline. A total of 30 new VFs occurred in 26 patients over 4 years. The incidence of morphometric VFs was 4.7% at 2 years and 13.6% at 4 years. Multivariate logistic regression analysis showed that previous VFs at baseline and increased CRP levels at 2 years were predictors of new VFs (odds ratio (OR) =12.8, 95% confidence interval (CI) = 3.6-45.3 and OR = 5.4, 95% CI = 1.4–15.9). The age-specific specific standardized prevalence ratio of morphometric VFs in AS was 3.3 (95% CI 2.1–4.5).

Conclusions

The incidence of morphometric VFs increased in AS. Previous VFs and increased CRP levels predicted future VFs. Further studies are needed to identify the effects of treatment interventions on the prevention of new VFs.

Effect of TNF-alpha inhibitor treatment on bone mineral density in patients with ankylosing spondylitis: a systematic review and meta-analysis

OBJECTIVES

Ankylosing spondylitis (AS) is a chronic inflammatory disease associated with an increased risk of osteoporosis and fractures. TNF inhibitors have been used to treat AS, but their effect on bone is unclear. Thus, we conducted a meta-analysis to study the effect of TNF inhibitors on spine and hip BMD in patients with AS.

METHODS

Two authors independently searched MEDLINE and PubMed for longitudinal studies that had assessed the effect of TNF inhibitors on BMD in patients with AS. Studies with a minimum follow-up period of 1 year were included.

RESULTS

Seven longitudinal studies and one randomized control trial were included, with a total of 568 AS patients (mean age range of 36-48 years and disease duration of 9-17 years). Lumbar spine BMD increased by 5.1% (95% CI: 4.0-6.1%, p = 0.00000) after 1 year of treatment with TNF inhibitors and by 8.6% (95% CI: 6.8-10.3%, p < 0.00001) after 2 years. Significant improvements in total hip BMD were also noted after 1 [1.8% (1.0-2.5%)] and 2 years [2.5% (1.9-3.0%)]. Compared to baseline, femoral neck BMD remained stable after 1 year [0.7% (-0.8% to 2.2%), p = 0.34]. No significant heterogeneity was noted amongst the included studies.

CONCLUSIONS

TNF inhibitors can increase lumbar spine and total hip BMD and maintain femoral neck BMD for up to 2 years in patients with AS. More research is needed to assess the effect of TNF inhibitors on bone quality and fracture risk.

Prevention and treatment of bone changes associated with exposure to glucocorticoids

Rheumatologic diseases are associated with a proinflammatory state, which is thought to lead to many of the bone changes seen in treatment-naive patients. However, glucocorticoids remain a common treatment option for rheumatologic diseases and are known to have a negative impact on bone through direct effects on bone cells and indirect effects on calcium absorption. Despite the anti-inflammatory effect of glucocorticoids, fracture risk rises within the first 3 months of treatment. As such, osteoporosis prevention and treatment needs to be considered in all patients started on chronic glucocorticoids (≥3 months of treatment). For very low risk patients, conservative management with non-pharmacologic strategies may be appropriate. For the moderate to high fracture risk patients treated with glucocorticoids, pharmacologic treatment with 1 of the 4 approved medications should be considered. The challenge of educating physicians and patients of the risks of glucocorticoid induced osteoporosis remain.