Association study of genes related to bone formation and resorption and the extent of radiographic change in ankylosing spondylitis

Association of ERAP1, IL23R and PTGER4 Polymorphisms with Radiographic Severity of Ankylosing Spondylitis

Background:

Radiographic severity of ankylosing spondylitis (AS) shows such great variance that some patients never develop syndesmophytes throughout the entire disease span, whereas some develop bamboo spine relatively early.

Objective:

To study the association between ERAP1, IL23R and PTGER4 single nucleotide polymorphisms (SNPs) and radiographic severity in AS patients.

Methods:

rs27044 and rs30187 (ERAP1), rs11209032 (IL23R) and rs10440635 (PTGER4) SNPs were genotyped in 235 AS patients fulfilling the modified New York criteria. Patients were classified as mild- and severe-AS according to modified Stoke AS spinal score (mSASSS). Mild-AS is defined as having mSASSS of “0” following at least 10 years of disease duration. Severe-AS is defined as having mSASSS of >20 (patients with mild vertebral changes (i.e. squaring or erosions) were omitted for clear stratification) regardless of disease duration.

Results:

The genotype distributions and allele frequencies of ERAP1 rs27044 and rs30187, IL23R rs11209032 and PTGER4 rs10440635 SNPs were similar in mild- (n=171, mSASSS=0, 55.6% HLA-B27 positive) and severe-AS patients (n=64, mSASSS=48.5±17.8, 73.4% HLA-B27 positive). After adjustment for clinical differences between groups (gender, disease duration, HLA-B27 and smoking status) by logistic regression analysis, none of the alleles in the investigated SNPs were found to be associated with radiographic severity of AS.

Conclusion:

In radiographically well-categorized AS patients, ERAP1 rs27044 and rs30187, IL23R rs11209032 and PTGER4 rs10440635 SNPs are not found to be associated with radiographic severity of AS.

The role of Dickkopf-1 in joint remodeling and fibrosis: A link connecting spondyloarthropathies and scleroderma?

BACKGROUND

Dickkopf-1 (Dkk-1) is a soluble inhibitor of the canonical Wnt pathway, which plays critical roles in embryonic development. Evidence suggests that this molecule regulates several aspects of both bone biology and fibrosis.

OBJECTIVES

To provide an overview of our current knowledge of the role of Dkk-1 in joint remodeling and fibrosis.

METHODS

We performed an electronic search (Medline) using the following key words: Dickkopf-1 (or Dkk-1), new bone formation, joint remodeling, ankylosing spondylitis, systemic sclerosis (or scleroderma), and fibrosis, supplemented by a manual search of references from retrieved articles.

RESULTS

Dkk-1 is a master regulator of joint remodeling in animal models of arthritis shifting the balance toward new bone formation when its expression is decreased and toward erosion/joint destruction when its expression is increased. In humans, evidence suggests that Dkk-1 may be dysfunctional in patients with ankylosing spondylitis, a prototype bone forming disease. Moreover, data from animal models indicate that Dkk-1 has a protective role against fibrosis in several organs. Recent data suggest that inhibiting the canonical Wnt pathway by overexpression of Dkk-1 could be a way to target TGF-β signaling in fibrotic diseases. Finally, B-cell depletion therapy in systemic sclerosis may exert its effects through TGF-β dependent upregulation of Dkk-1.

CONCLUSIONS

Dkk-1 appears to play a crucial role in both joint remodeling/ectopic ossification and fibrosis, and may be a prospective therapeutic modality for fibrotic diseases or diseases characterized by pathologic joint remodeling.

Detection of novel diagnostic antibodies in ankylosing spondylitis: An overview

Ankylosing spondylitis (AS) is a debilitating, chronic, rheumatic disease characterized by inflammation and new bone formation resulting in fusion of the spine and sacroiliac joints. Since early treatment is impeded by a delayed diagnosis, it is highly important to find new biomarkers that improve early diagnosis and may also contribute to a better assessment of disease activity, prognosis and therapy response in AS. Because of the absence of rheumatoid factor, AS was long assumed to have a seronegative character and antibodies are thus not considered a hallmark of the disease. However, emerging evidence suggests plasma cells and autoantibodies to be involved in the disease course. In this review, the role of B cells and antibodies in AS is discussed. Furthermore, an overview is provided of antibodies identified in AS up till now, and their diagnostic potential. Many of these antibody responses were based on small study populations and further validation is lacking. Moreover, most were identified by a hypothesis-driven approach and thus limited to antibodies against targets that are already known to be involved in AS pathogenesis. Hence, we propose an unbiased approach to identify novel diagnostic antibodies. The already successfully applied techniques cDNA phage display and serological antigen selection will be used to identify antibodies against both known and new antigen targets in AS plasma. These newly identified antibodies will enhance early diagnosis of AS and provide more insight into the underlying disease pathology, resulting in a more effective treatment strategy and eventually an improved disease outcome.

Serum DKK-1 level in the development of ankylosing spondylitis and rheumatic arthritis: a meta-analysis

To explore the association of serum Dickkopf-1 (DKK-1) levels with the development of ankylosing spondylitis (AS) and rheumatic arthritis (RA) in humans, databases including PubMed, EBSCO, Springerlink, Ovid, WANFANG and China National Knowledge Infrastructure (CNKI) were searched to identify relevant studies. On the basis of rigorous inclusion and exclusion criteria, case–control studies of the relationships between serum DKK-1 levels and AS and RA published before December 2014 were enrolled. Statistical analyses were performed using Comprehensive Meta-analysis 2.0 (CMA 2.0). Seven case–control trials with a total of 300 AS patients, 136 RA patients and 232 healthy controls were included in this study. Meta-analysis results revealed that DKK-1 serum levels were significantly higher in AS patients than in normal controls (standard mean differences (s.m.d.)=0.301, 95% confidence interval (CI)=0.094–0.507, P=0.004), whereas no significant difference in DKK-1 serum levels was observed between RA patients and healthy controls (s.m.d.=0.798, 95% CI=−2.166–3.763, P=0.598). Serum DKK-1 level may be closely related to the development of AS but not of RA.

IL-23/Th17 axis is not influenced by TNF-blocking agents in ankylosing spondylitis patients

Background

Advances in pathophysiology and treatment of ankylosing spondylitis (AS) was recently demonstrated. However, the effect of anti-TNF in the newly described inflammatory pathways involved pathogenesis of this disease remains to be determined. The aim of our study was, therefore, to investigate long-term influence of anti-TNF drugs in IL-23/IL-17 axis of AS patients and their possible correlation with treatment, clinical, laboratory and radiographic parameters.

Methods

Eighty-six AS anti-TNF naïve patients, 47 referred for anti-TNF therapy (active-AS; BASDAI ≥ 4) and 39 with BASDAI < 4 (control-AS) were included. The active group was evaluated at baseline, 12-months and 24-months after TNF blockade and compared at baseline to control-AS group and to 47 healthy age- and gender-matched controls. Plasma levels of IL-17A, IL-22, IL-23 and PGE2 were measured. Non-steroidal anti-inflammatory drugs (NSAIDs) intake were recorded every 6 months. Radiographic severity and progression was assessed by mSASSS at baseline and 24 months after therapy.

Results

At baseline, active-AS group presented higher IL-23 and PGE2 levels compared to control-AS group (p < 0.001 and p = 0.008) and to healthy controls (p < 0.001 and p = 0.02). After 24-months of TNF blockade, IL-23 and PGE2 remained elevated with higher levels compared with the healthy group (p < 0.001 and p = 0.03) in spite of significant improvements in all clinical/inflammatory parameters (p < 0.001). Further analysis of 27 anti-TNF-treated patients who achieved a good response (ASDAS-CRP < 2.1,with a drop ≥ 1.1) at 24-months revealed that IL-23 plasma levels remained higher than healthy controls (p < 0.001) and higher than control-AS group with similar disease activity (ASDAS-CRP < 2.1, p = 0.01). In active-AS group (n = 47), there was a strong correlation between IL-23 and IL-17A at baseline, 12-months and 24-months after anti-TNF therapy (p ≤ 0.001).

Conclusion

This study provides novel data demonstrating that the IL-23/IL-17 axis is not influenced by TNF blockade in AS patients despite clinical and inflammation improvements and NSAID intake.

Ankylosing spondylitis: A state of the art factual backbone

Ankylosing spondylitis (AS) is a chronic inflammatory disease that affects 1% of the general population. As one of the most severe types of spondyloarthropathy, AS affects the spinal vertebrae and sacroiliac joints, causing debilitating pain and loss of mobility. The goal of this review is to provide an overview of AS, from the pathophysiological changes that occur as the disease progresses, to genetic factors that are involved with its onset. Considering the high prevalence in the population, and the debilitating life changes that occur as a result of the disease, a strong emphasis is placed on the diagnostic imaging methods that are used to detect this condition, as well as several treatment methods that could improve the health of individuals diagnosed with AS.

Increase in Dickkopf-1 Serum Level in Recent Spondyloarthritis. Data from the DESIR Cohort

OBJECTIVES

To investigate DKK-1 and SOST serum levels among patients with recent inflammatory back pain (IBP) fulfilling ASAS criteria for SpA and associated factors.

METHODS

The DESIR cohort is a prospective, multicenter French cohort of 708 patients with early IBP (duration >3 months and <3 years) suggestive of AxSpA. DKK-1 and SOST serum levels were assessed at baseline and were compared between the subgroup of patients fulfilling ASAS criteria for SpA (n = 486; 68.6%) and 80 healthy controls.

RESULTS

Mean SOST serum levels were lower in ASAS+ patients than healthy controls (49.21 ± 25.9 vs. 87.8 ± 26 pmol/L; p<0.0001). In multivariate analysis, age (p = 5.4 10-9), CRP level (p<0.0001) and serum DKK-1 level (p = 0.001) were associated with SOST level. Mean DKK-1 serum levels were higher in axial SpA patients than controls (30.03 ± 15.5 vs. 11.6 ± 4.2 pmol/L; p<0.0001). In multivariate analysis, DKK-1 serum levels were associated with male gender (p = 0.03), CRP level (p = 0.006), SOST serum level (p = 0.002) and presence of sacroiliitis on radiography (p = 0.05). Genetic association testing of 10 SNPs encompassing the DKK-1 locus failed to demonstrate a significant contribution of genetics to control of DKK-1 serum levels.

CONCLUSIONS

DKK-1 serum levels were increased and SOST levels were decreased among a large cohort of patients with early axial SpA compared to healthy controls. DKK-1 serum levels were mostly associated with biological inflammation and SOST serum levels.

Genetic Variants in Cyclooxygenase-2 Contribute to Post-treatment Pain among Endodontic Patients

INTRODUCTION

Nonsteroidal anti-inflammatory drugs (NSAIDs) have a well-established analgesic efficacy for inflammatory pain. These drugs exert their effect by inhibiting the enzyme cyclooxygenase (COX) and are commonly used for the management of pain after endodontic treatment. There are 2 distinct isoforms of COX: COX-1, which is constitutively expressed, and COX-2, which is primarily induced by inflammation. Previous studies have shown that functional human genetic variants of the COX-2 gene may explain individual variations in acute pain. The present study extends this work by examining the potential contribution of the 2 COX isoforms to pain after endodontic treatment.

METHODS

Ninety-four patients treated by endodontic residents at the University of North Carolina School of Dentistry were enrolled into a prospective cohort study. Data on potential predictors of post-treatment pain were collected, and all patients submitted saliva samples for genetic analysis. Nonsurgical root canal therapy was performed, and participants recorded pain levels for 5 days after.

RESULTS

In this study, 63% of patients experienced at least mild pain after root canal therapy, and 24% experienced moderate to severe pain. The presence of pretreatment pain was correlated with higher post-treatment pain (P = .01). Elevated heart rate (P = .02) and higher diastolic blood pressure (P = .024) were also correlated with decreased post-treatment pain. Finally, we identified genetic variants in COX-2 (haplotype composed of rs2383515 G, rs5277 G, rs5275 T, and rs2206593 A) associated with post-treatment pain after endodontic treatment (P = .025).

CONCLUSIONS

Understanding the genetic basis of pain after endodontic treatment will advance its prevention and management.

Biomarkers for diagnosis, monitoring of progression, and treatment responses in ankylosing spondylitis and axial spondyloarthritis

With the growing awareness of the impact of chronic back pain and axial spondyloarthritis and recent breakthroughs in genetics and the development of novel treatments which may impact best on early disease, the need for markers that can facilitate early diagnosis and profiling those individuals at the highest risk for a bad outcome has never been greater. The genetic basis of ankylosing spondylitis has been considerably advanced, and HLA-B27 testing has a role in the diagnosis. Knowledge is still incomplete of the rest of the genetic contribution to disease susceptibility, and it is likely premature to use extensive genetic testing (other than HLA-B27) for diagnosis. Serum and plasma biomarkers have been examined extensively in assessing disease activity, treatment response, and as predictors or radiographic severity. For assessing disease activity, other than C-reactive protein and erythrocyte sedimentation rate, the most work has been in examining cytokines (particularly interleukin 17 and 23), matrix metalloproteinase (MMP) markers (particularly MMP3). For assessing those at the highest risk for radiographic progression, biomarkers of bony metabolism, cartilage and connective tissue degradation products, and adipokines have been most extensively assessed. The problem is that no individual biomarkers has been reproducibly shown to assess disease activity or predict outcome, and this area still remains an unmet need, of relevance to industry stakeholders, to regulatory bodies, to the healthcare system, to academic investigators, and finally to patients and providers.