Serum levels of Dkk-1, sclerostin and VEGF in patients with ankylosing spondylitis and their association with smoking, and clinical, inflammatory and radiographic parameters

Serum concentration of dickkopf-related protein 1 (DKK1) in psoriatic arthritis in the context of bone remodelling

Psoriatic arthritis (PsA) is a chronic inflammatory disease, characterised by the pathological occurrence of two opposite phenomena-osteoresorption and osteogenesis. Dickkopf-related protein 1 (DKK1) which inhibits the Wingless protein (Wnt) signalling pathway has been shown to be a master regulator of bone remodeling in inflammatory rheumatic diseases. However, the exact relationship between DKK1 serum level and bone remodelling is not clear. The goal of this study is to review state-of-the-art knowledge on the association of serum DKK1 with a bone remodelling in PsA. The MEDLINE-PubMed, EMBASE, Scopus, Web of Science and DOAJ databases were searched for appropriate papers. The English terms: 'DKK1', 'Dickkopf-1' 'Dickkopf related protein 1', 'psoriatic arthritis' and 'PsA' were used for search purposes. Eight original articles and two reviews were identified up to August 2023. In four out of 8 discussed studies DKK1 serum level was higher in PsA patients than in healthy controls [Dalbeth, p < 0.01; Diani, p < 0.001; Chung, p < 0.01; Abd el Hamid, p < 0.001)], it was comparable in another (Daousiss, p = 0.430) and was lower in two (Fassio2017, p < 0.05; Fassio2019, p < 0.05). In one study, the comparative groups included patients with axial spondyloarthritis, where DKK1 serum levels were lower in PsA groups [Jadon, peripheral PsA, p = 0.01]. The true relative serum concentration of DKK1 in PsA, as well as its influence on osteogenesis and osteoresorption, is still equivocal. Further studies on this matter with consistent and stringent methodology are warranted.

The Role of Sclerostin in Rheumatic Diseases: A Review

Systemic connective tissue disorders constitute a heterogenous group of autoimmune diseases with the potential to affect a range of organs. Rheumatoid arthritis (RA) is a chronic, progressive, autoimmune inflammatory disease affecting the joints. Systemic lupus erythematosus (SLE) may manifest with multiple system involvement as a result of inflammatory response to autoantibodies. Spondyloarthropathies (SpAs) such as ankylosing spondylitis (AS) or psoriatic arthritis (PsA) are diseases characterised by the inflammation of spinal joints, paraspinal tissues, peripheral joints and enthesitis as well as inflammatory changes in many other systems and organs. Physiologically, sclerostin helps to maintain balance in bone tissue metabolism through the Wnt/β-catenin pathway, which represents a major intracellular signalling pathway. This review article aims to present the current knowledge on the role of sclerostin in the Wnt/β-catenin pathway and its correlation with clinical data from RA, SLE, AS and PsA patients.

Serum DKK-1 level in ankylosing spondylitis: insights from meta-analysis and Mendelian randomization

Objective

The purpose of this study was to precisely evaluate the serum Dickkopf-1 (DKK-1) level in patients with ankylosing spondylitis (AS) relative to that in normal controls and to test the causal relationship between DKK-1 and the risk of AS.

Methods

Embase, PubMed, Web of Science, WANFANG DATA, VIP, and China National Knowledge Infrastructure (CNKI) were comprehensively searched until July 2022 for pertinent studies. The pooled standardized mean difference (SMD) with a 95% confidence interval (CI) was calculated by the fixed or random-effect model. In Mendelian randomization (MR) analysis on the causal relationship between serum DKK-1 level and AS risk, the inverse variance weighting method (IVW), MR-Egger regression, weighted median method, and weighted pattern method were applied. Sensitivity analyses, including the horizontal pleiotropy test, heterogeneity test, and leave-one-out test, were also performed.

Results

The meta-analysis of 40 studies containing 2,371 AS patients and 1,633 healthy controls showed that there was no significant difference in DKK-1 serum level between AS patients and normal controls (pooled SMD=0.207, 95% CI =-0.418-0.832, P=0.516). The subgroup analysis of the CRP ≤ 10 mg/L group showed that AS patients had higher serum DKK-1 concentration than the healthy controls (SMD=2.267, 95% CI = 0.102-4.432, P=0.040). Similarly, MR analysis also demonstrated no significant association between DKK-1 serum level and AS (IVW OR=0.999, 95% CI = 0.989-1.008, P=0.800). All sensitivity analyses revealed consistent results.

Conclusions

There was no significant change in serum DKK-1 concentration between AS patients and healthy controls. In addition, no causal relationship exists between serum DKK-1 levels and AS risk.

Association of vascular endothelial growth factor serum levels with ankylosing spondylitis in Egyptian patients

Background

Ankylosing spondylitis (AS) is one of inflammatory rheumatic diseases which result in wide range of manifestations on the musculoskeletal system and axial joint specifically. Endothelial cell migration and proliferation, as well as subsequent neoangiogenesis and remodelling in autoimmune disorders, are pathogenic mechanisms that are fundamental to inflammation activation and angiogenesis. The development of advanced lesions is thought to involve vascular proliferation as well as vascular endothelial growth factor (VEGF), which serves a regulatory role. It was found that AS patients had increased serum levels of VEGF, which were linked to the disease activity.

Aim of the work

The purpose of this study is to measure serum VEGF levels in Egyptian AS patients and assess their relation to disease-related variables, including radiographic findings.

Results

VEGF serum levels showed a highly significant positive correlation with Bath Ankylosing Spondylitis Functional Index (BASFI) and modified Stroke Ankylosing Spondylitis Spinal Score (MSASS) (p < 0.001); also, there was a significant correlation between the VEGF values and the Ankylosing Spondylitis Disease Activity Index (ASDAS) and the New York x-ray sacroiliac score.

Conclusions

These findings and data illustrate the strong relationship between ASDAS and VEGF and the radiographic score in AS patients. ASDAS combined with VEGF not only is considered a tool for determining the level of disease activity only but also is considered as an indicator for the assessment of the syndesmophytes formation, which performs a crucial role in the prognosis and outcome in AS patients.

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.

Sclerostin and Its Involvement in the Pathogenesis of Idiopathic Scoliosis

Idiopathic scoliosis is a disorder of unknown etiology. Bone biopsies from idiopathic scoliosis patients revealed changes at cellular and molecular level. Osteocytic sclerostin is downregulated, and serum level of sclerostin is decreased. Osteocytes in idiopathic scoliosis appear to be less active with abnormal canaliculi network. Differentiation of osteoblasts to osteocytes is decelerated, while Wnt/β-catenin signaling pathway is overactivated and affects normal bone mineralization that leads to inferior mechanical properties of the bone, which becomes susceptible to asymmetrical forces and causes deformity of the spinal column. Targeting bone metabolism during growth by stimulating sclerostin secretion from osteocytes and restoring normal function of Wnt/β-catenin signaling pathway could, in theory, increase bone strength and prevent deterioration of the scoliotic deformity.

The TNF-NF-kB-DKK1 Axis Promoted Bone Formation in the Enthesis of Ankylosing Spondylitis

Objective

This study aimed to determine the serum Dickkopf 1 (DKK1) levels in ankylosing spondylitis (AS) patients and decipher the mechanism of tumor necrosis factor (TNF)-mediated DKK1 regulation in human AS enthesis cells.

Methods

The sera were obtained from 103 patients with AS and 30 healthy controls (HCs) The enthesis of facet joints were obtained from 4 AS patients and 5 controls The serum levels of DKK1 were measured using ELISA and compared between AS and HCs The impact of TNF on DKK1 expression in human primary spinal enthesis cells was evaluated using various molecular biology techniques and bone formation indicators.

Results

AS patients showed higher serum DKK1 levels than HCs after adjusting for age (9174 [6153∼1,3100] pg/mL vs 8262 [6703∼9278] pg/mL, p=0043) TNF treatment promoted bone formation and DKK1 expression in both control enthesis cells and those of AS This enhanced bone formation by TNF was pronounced in AS-enthesis than those of controls Mechanically, TNF induced NF-kB activation upregulates the DKK1 transcript level While, NF-kB inhibitor led to downregulate DKK1 expression in the enthesis Besides, DKK1 overexpression promoted bone formation in enthesis.

Conclusion

TNF induced DKK1 expression in the enthesis through NF-kB activation TNF-induced DKK1 expression may play a bone formation in the radiologic progression of ankylosing spondylitis.

Relationship between smoking, clinical, inflammatory, and radiographic parameters in patients with ankylosing spondylitis

Background

Ankylosing spondylitis (AS) is an autoimmune multisystemic disease that attacks the spine, sacroiliacs, and often causes asymmetrical peripheral oligoarthritis. It results from the interaction between the genetic factors mainly Human Leukocyte Antigen B27 (HLA B27) and environmental factors. Current smoking has been reported to be a major risk factor for the incidence and progression of ankylosing spondylitis. So, we aim to explore the relationship between smoking and each of the clinical, inflammatory markers, functional limitation, and radiographic progression in ankylosing spondylitis patients.

Results

Fifty ankylosing spondylitis patients were included in this study. Comparisons of clinical data, radiographic, and inflammatory markers among smokers and nonsmokers revealed that AS current smokers showed a statistically significant decrease in chest expansion, increase in the occiput to wall distance (p < 0.001**), higher inflammatory marker, higher disease activity indices (Ankylosing Spondylitis Disease Activity Score, Bath Ankylosing Spondylitis Disease Activity Index), higher Bath Ankylosing Spondylitis functional index, and modified Stoke Ankylosing Spondylitis Spine Score than nonsmokers (P < 0.001**). The smoking index was positively correlated with BASFI, ASDAS, (mSASSS) (r = 0.584, p = 0.005*) and negatively correlated with chest expansion.

Conclusions

Current smoking in ankylosing spondylitis patients is associated with higher disease activity, inflammatory markers, functional disability, and radiological progression. This may add to the disease burden and thus interferes with the personal daily activities, physical mobility, life quality, and the response to TNFi therapy. So, stopping smoking is a mandatory step in controlling the disease activity and having favorable outcome.

Association of Circulating Vascular Endothelial Growth Factor Levels With Autoimmune Diseases: A Systematic Review and Meta-Analysis

Background

Autoimmune diseases (ADs) are characterized by immune-mediated tissue damage, in which angiogenesis is a prominent pathogenic mechanism. Vascular endothelial growth factor (VEGF), an angiogenesis modulator, is significantly elevated in several ADs including rheumatoid arthritis (RA), systemic sclerosis (SSc), and systemic lupus erythematosus (SLE). We determined whether circulating VEGF levels were associated with ADs based on pooled evidence.

Methods

The analyses included 165 studies from the PubMed, EMBASE, Cochrane Library, and Web of Science databases and fulfilled the study criteria. Comparisons of circulating VEGF levels between patients with ADs and healthy controls were performed by determining pooled standard mean differences (SMDs) with 95% confidence intervals (CIs) in a random-effect model using STATA 16.0. Subgroup, sensitivity, and meta-regression analyses were performed to determine heterogeneity and to test robustness.

Results

Compared with healthy subjects, circulating VEGF levels were significantly higher in patients with SLE (SMD 0.84, 95% CI 0.25-1.44, P = 0.0056), RA (SMD 1.48, 95% CI 0.82-2.15, P <0.0001), SSc (SMD 0.56, 95% CI 0.36-0.75, P <0.0001), Behcet's disease (SMD 1.65, 95% CI 0.88-2.41, P <0.0001), Kawasaki disease (SMD 2.41, 95% CI 0.10-4.72, P = 0.0406), ankylosing spondylitis (SMD 0.78, 95% CI 0.23-1.33, P = 0.0052), inflammatory bowel disease (SMD 0.57, 95% CI 0.43-0.71, P <0.0001), psoriasis (SMD 0.98, 95% CI 0.62-1.34, P <0.0001), and Graves' disease (SMD 0.69, 95% CI 0.20-1.19, P = 0.0056). Circulating VEGF levels correlated with disease activity and hematological parameters in ADs.

Conclusion

Circulating VEGF levels were associated with ADs and could predict disease manifestations, severity and activity in patients with ADs.

Systematic Review Registration

PROSPERO, identifier CRD42021227843.

Vascular Endothelial Growth Factor Biology and Its Potential as a Therapeutic Target in Rheumatic Diseases

Rheumatic diseases constitute a diversified group of diseases distinguished by arthritis and often involve other organs. The affected individual has low quality of life, productivity even life-threatening in some severe conditions. Moreover, they impose significant economic and social burdens. In recent years, the patient outcome has been improved significantly due to clearer comprehension of the pathology of rheumatic diseases and the effectiveness of "treat to target" therapies. However, the high cost and the adverse effects are the concerns and full remissions are not often observed. One of the main processes that contributes to the pathogenesis of rheumatic diseases is angiogenesis. Vascular endothelial growth factor (VEGF), a central mediator that regulates angiogenesis, has different isoforms and functions in various physiological processes. Increasing evidence suggests an association between the VEGF system and rheumatic diseases. Anti-VEGF and VEGF receptor (VEGFR) therapies have been used to treat several cancers and eye diseases. This review summarizes the current understanding of VEGF biology and its role in the context of rheumatic diseases, the contribution of VEGF bioavailability in the pathogenesis of rheumatic diseases, and the potential implications of therapeutic approaches targeting VEGF for these diseases.

The Effects of Sex and Estrogen on Radiographic Progression of Ankylosing Spondylitis in Korean Patients

Objective

Ankylosing spondylitis (AS) is a chronic inflammatory disease with obvious male preponderance Males show more severe radiographic manifestations compared with females This study aimed to evaluate the effects of sex and estrogen on the radiographic progression of AS.

Methods

A total of 101 patients with AS were included in this study All of the radiographs were scored using the modified Stoke AS Spine Score (mSASSS) Serum levels of 17β-estradiol (E2), dickkopf-1 (Dkk1), and leptin were detected by enzyme-linked immunosorbent assay The generalized estimating equations model was used to evaluate factors associated with spinal radiographic progression.

Results

The mean age at disease onset was 273±107 years, and 16 patients (158%) were female In the multivariable analysis, body mass index (β-coefficient=012; p=0047) and levels of Dkk1 (β-coefficient=-011; p<0001), and female (β-coefficient=-140; p=0001) were associated with radiographic progression Among male patients with AS, baseline C-reactive protein (β=011; p=0005) and mSASSS (β=021; p=0030) were also associated with radiographic progression E2 and leptin levels were not significantly related to the radiographic progression.

Conclusion

Although female patients were associated with less radiographic progression in AS, there was no significant relationship between serum estrogen level and radiographic progression Results of current study suggests that genetic factors or other environmental factors associated with female may influence radiographic progression in patients with AS.

Cytokine "fine tuning" of enthesis tissue homeostasis as a pointer to spondyloarthritis pathogenesis with a focus on relevant TNF and IL-17 targeted therapies

A curious feature of axial disease in ankylosing spondylitis (AS) and related non-radiographic axial spondyloarthropathy (nrAxSpA) is that spinal inflammation may ultimately be associated with excessive entheseal tissue repair with new bone formation. Other SpA associated target tissues including the gut and the skin have well established paradigms on how local tissue immune responses and proven disease relevant cytokines including TNF and the IL-23/17 axis contribute to tissue repair. Normal skeletal homeostasis including the highly mechanically stressed entheseal sites is subject to tissue microdamage, micro-inflammation and ultimately repair. Like the skin and gut, healthy enthesis has resident immune cells including ILCs, γδ T cells, conventional CD4+ and CD8+ T cells and myeloid lineage cells capable of cytokine induction involving prostaglandins, growth factors and cytokines including TNF and IL-17 that regulate these responses. We discuss how human genetic studies, animal models and translational human immunology around TNF and IL-17 suggest a largely redundant role for these pathways in physiological tissue repair and homeostasis. However, disease associated immune system overactivity of these cytokines with loss of tissue repair “fine tuning” is eventually associated with exuberant tissue repair responses in AS. Conversely, excessive biomechanical stress at spinal enthesis or peripheral enthesis with mechanically related or degenerative conditions is associated with a normal immune system attempts at cytokine fine tuning, but in this setting, it is commensurate to sustained abnormal biomechanical stressing. Unlike SpA, where restoration of aberrant and excessive cytokine “fine tuning” is efficacious, antagonism of these pathways in biomechanically related disease may be of limited or even no value.

Gene-gene interaction and association of Wnt/&Beta;-catenin signalling pathway gene polymorphisms with ankylosing spondylitis susceptibility in the Chinese Han population

Objectives: To explore the genetic interaction between Wnt/β-catenin signalling pathway genes and ankylosing spondylitis (AS) in the Chinese population.Methods: Six single-nucleotide polymorphisms (SNPs) in DKK1, LRP5, LRP6, and SOST genes were genotyped in 673 AS patients and 687 healthy controls by using SNPs can Technic. Single marker genetic association analysis was performed. Haplotypes were constructed after linkage disequilibrium analysis; additive, multiplicative, and higher-order interactions were analysed.Results: The DKK1 gene rs1569198 polymorphism was significantly associated with AS susceptibility in females (χ² = 4.55, p = .03), but the association disappeared after Bonferroni correction. Moreover, a haplotype (T-G) in the DKK1 gene showed a protective role in AS susceptibility in females (p = .04). Significant additive interactions were observed between DKK1: rs1896368 and LRP5: rs3736228, relative excess risk due to interaction (RERI) = 0.40, 95% CI = 0.08 - 0.71; attributable proportion due to interaction (AP) = 51%, 95% CI = 0.07 - 0.94, DKK1: rs1569198 and LRP5: rs3736228 (RERI = 0.49, 95% CI = 0.12 - 0.86; AP = 49%, 95% CI = 0.17 - 0.82), LRP5: rs3736228 and SOST: rs4792909 (RERI = 0.33, 95% CI = 0.002 - 0.65; AP = 41%, 95% CI = 0.01 - 0.81) in the dominant model.Conclusions: Our research implies a potential gene-gene interaction, thus revealing the importance of the Wnt/β-catenin signalling pathway for understanding the genetic architecture of AS.

Serum Sclerostin and Bone Morphogenetic Protein-2 Levels in Patients with Ankylosing Spondylitis: A Meta-Analysis

Various studies have investigated the serum sclerostin and bone morphogenetic protein-2 (BMP-2) levels in patients with ankylosing spondylitis (AS), but the results were inconsistent. The aim of this meta-analysis was to synthetically assess the associations of serum levels of sclerostin and BMP-2 with AS. Multiple electronic databases were searched to locate relevant articles published before November 2018. Pooled standard mean difference (SMD) with 95% confidence interval (CI) was calculated by the random-effect model. Totally, 21 studies were included. Meta-analysis results showed no significant difference between AS group and control group in serum sclerostin levels (SMD = 0.098, 95% CI - 0.395 to 0.591, p = 0.697). Nevertheless, serum BMP-2 levels in AS patients were higher than that in controls (SMD = 1.184, 95% CI 0.209 to 2.159, p = 0.017). Subgroup analysis demonstrated that European and South American AS patients had lower serum levels of sclerostin than controls. AS patients with age ≥ 40 years, erythrocyte sedimentation rate (ESR) ≤ 20 mm/h and Bath Ankylosing Spondylitis Functional Index (BASFI) < 4 had statistically significant lower serum sclerostin concentrations compared to controls. Chinese and Korean AS patients as well as patients with lower CRP had higher serum BMP-2 levels than controls, and country may be a source of heterogeneity across the studies. No publication bias existed and sensitivity analysis confirmed the stability of results. Serum BMP-2, but not sclerostin levels may be closely related to the development of AS.

Association of Genetic Variants of RANK, RANKL, and OPG with Ankylosing Spondylitis Clinical Features in Taiwanese

Ankylosing spondylitis (AS) is a chronic inflammatory disease that leads to spinal ankylosis. The receptor activator of the nuclear factor-kappa (RANK), RANK ligand, and osteoprotegerin (OPG) (RANK/RANKL/OPG) pathway plays critical roles in bone metabolism and the immune system. The current study was aimed at investigating whether six single-nucleotide polymorphisms (SNPs) within the RANK, RANKL, and OPG genes essential for bone homeostasis are associated with AS. Genotype distributions, allele and haplotype frequencies, were compared between 1120 AS patients and 1435 healthy controls and among AS patients with stratification by syndesmophyte formation, onset age, and HLA-B27 positivity. We found that RANKL SNPs were associated with AS syndesmophyte formation. Notably, the RANKL SNP haplotype rs7984870C/rs9533155G/rs9525641C was negatively associated with AS susceptibility and appeared to protect against syndesmophyte formation in AS. Functionally, RANKL promoter SNPs (rs9525641 C/T and rs9533155 G/C) affected DNA-protein complex formation and promoter activity in promoter reporter analyses. The OPG SNP haplotype rs2073618G/rs3102735T was significantly associated with HLA-B27 negativity in AS patients. Furthermore, AS patients with syndesmophyte formation had significantly lower levels of soluble RANKL levels than those without syndesmophyte formation. Our data suggested a role for RANKL in AS susceptibility and severity.

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.

Sclerostin rather than Dickkopf-1 is associated with mSASSS but not with disease activity score in patients with ankylosing spondylitis

OBJECTIVE

To determine the serum levels of Dickkopf-1 (DKK-1) and sclerostin, as well as their correlations with the structural damage assessed by modified stoke ankylosing spondylitis spine score (mSASSS) and the disease activity evaluated by ankylosing spondylitis disease activity score (ASDAS) in patients with ankylosing spondylitis (AS).

METHODS

Eighty-eight AS patients, 26 rheumatoid arthritis (RA) patients, and 26 age- and gender-matched healthy controls (HC) were collected from rheumatic clinic of the Second Affiliated Hospital of Zhejiang University, School of Medicine, between March 2015 and July 2015. Demographic data, parameters of ASDAS, and image evaluations of spine (i.e., mSASSS) were collected. The serum levels of DKK-1 and sclerostin were measured using commercially available ELISA kits.

RESULTS

Both DKK-1 and sclerostin were significantly higher in the AS patients than in the controls (1855 ± 84.58 vs. 1406 ± 99.76 pg/ml and 106 ± 6.75 vs. 62.78 ± 6.39 pmol/l, respectively, P < 0.05). The correlation analysis suggested a negative correlation between serum sclerostin and mSASSS (P = 0.019, r² = 0.062). DKK-1 had a trend of positive correlation with mSASSS, but was not statistically significant (P > 0.05). There was no association between the serum levels of DKK-1 or sclerostin and disease activity assessed by ASDAS (P > 0.05). DKK-1 and sclerostin had a negative correlation (P = 0.013, r² = 0.07).

CONCLUSION

In the present study, the expressions of serum DKK-1 and sclerostin were independent of disease activity. Sclerostin was negatively correlated with the mSASSS, which suggests that sclerostin may be a potential marker indicating the spine ossification process in AS. The specific mechanism remains to be investigated.

Serum VEGF Level Is Different in Adolescents Smoking Waterpipe versus Cigarettes: The Irbid TRY

Waterpipe (Wp) use is associated with most devastating diseases and particularly popular among adolescents. Vascular endothelium growth factor (VEGF) is essential for generating new vessels. The effect of smoking tobacco on VEGF is controversial and unknown among adolescents. Therefore, the current study compared serum VEGF in adolescents smoking cigarettes (Cg) only (9.3%), Wp only (19.6%), and dual (Wp and Cg) (36.4%) versus nonsmokers (34.6%) in adolescents. A self-reported questionnaire and enzyme-linked immunosorbent assay (ELISA) were used to obtain smoking status and serum VEGF, respectively, in 475 (age: 14.6 ± 1.0 years) boys (n = 263) and girls (n = 212) from Irbid, Jordan. The analysis showed that smoking status (R² = 0.021; p = 0.001) and gender (R² = 0.035; p = 0.000) can predict VEGF. Furthermore, 2-way-ANCOVA revealed that VEGF was lower in the dual cohort versus the Cg (33.4%; p = 0.04) and nonsmoker (29.6%; p = 0.003) cohorts; VEGF in smokers, was lower (33.6%; p = 0.04) in the Wp versus nonsmokers in the boys but not the girls. These results are unique and suggest that smoking lowers VEGF, which might adversely affect vascular growth and function. This is alarming given that adolescents are still in the development stage and smoking, particularly Wp, is popular among them. Therefore, interventions targeting smoking among schoolchildren are urgently needed to avoid the negative effects of smoking, especially on vascular health.

Parathyroid hormone is a determinant of serum Dickkopf-1 levels in ankylosing spondylitis

Available studies reported contradictory results about serum levels Dickkopf-1 (DKK1), an inhibitor of Wnt signaling in patients with ankylosing spondylitis (AS). In previous studies, we observed in other conditions that parathyroid hormone (PTH) serum levels were an important determinant of DKK1 serum levels. The aim of the present study was to investigate it in patients with AS. We recruited 71 patients diagnosed with AS. Levels of C-reactive protein (CRP), DKK1, PTH, 25OH-vitamin D, and bone turnover markers (intact N-propeptide of type I collagen, P1NP, and C-terminal telopeptide of type I collagen, CTX) were measured and compared to healthy controls (HC). Dual X-ray absorptiometry at lumbar spine and proximal femoral site was used for bone mineral density (BMD) assessment and spine X-rays were also performed. PTH serum levels were found to be significantly higher in AS patients than in HC (33.8 ± 14.11 vs 24.8 ± 13 pg/ml, p = 0.002), while mean DKK1 serum levels were lower than in HC (23.3 ± 13.1 vs 29.8 ± 15.9 pmol/l, p = 0.009). A positive correlation between DKK1 and PTH (correlation coefficient + 0.25, p = 0.03) was observed; it remained significant in a multivariate analysis. In patients with longer disease duration, DKK1 was also positively correlated with CTX (coefficient 0.42, p = 0.01), and PTH was higher in those patients with low BMD (Z-score ≤ - 1) at any site (p = 0.04). Also in AS, PTH is an important determinant of DKK1 serum levels and should be evaluated in studies on DKK1. PTH might have a role in bone involvement in AS, also through the Wnt pathway.

The Effect of Tobacco Smoking on Musculoskeletal Health: A Systematic Review

This systematic review explored associations between smoking and health outcomes involving the musculoskeletal system. AMSTAR criteria were followed. A comprehensive search of PubMed, Web of Science, and Science Direct returned 243 articles meeting inclusion criteria. A majority of studies found smoking has negative effects on the musculoskeletal system. In research on bones, smoking was associated with lower BMD, increased fracture risk, periodontitis, alveolar bone loss, and dental implant failure. In research on joints, smoking was associated with increased joint disease activity, poor functional outcomes, and poor therapeutic response. There was also evidence of adverse effects on muscles, tendons, cartilage, and ligaments. There were few studies on the musculoskeletal health outcomes of secondhand smoke, smoking cessation, or other modes of smoking, such as waterpipes or electronic cigarettes. This review found evidence that suggests tobacco smoking has negative effects on the health outcomes of the musculoskeletal system. There is a need for further research to understand mechanisms of action for the effects of smoking on the musculoskeletal system and to increase awareness of healthcare providers and community members of the adverse effects of smoking on the musculoskeletal system.

Serum CCL11 level is associated with radiographic spinal damage in patients with ankylosing spondylitis

The clinical significance of C-C motif chemokine11 (CCL11) in bone metabolism in ankylosing spondylitis (AS) is not clearly elucidated. Thus, this cross-sectional study aimed to compare serum levels of CCL11 between patients with AS and healthy controls and to investigate the relationship between serum levels of CCL11 and radiographic spinal damage in patients with AS. We consecutively recruited 55 male patients with AS and 26 age- and sex-matched healthy controls. Serum levels of CCL11, tumor necrosis factor-α (TNF-α), interleukin-17, and Dickkopf-1 (DKK-1) were measured with commercially available enzyme-linked immunosorbent assay kits. Radiographs were scored according to the modified Stoke ankylosing spondylitis spine score (mSASSS), and syndesmophytes were defined as mSASSS ≥ 2. The serum levels of CCL11 in AS patients with syndesmophytes were significantly higher than those in AS patients without syndesmophytes (p = 0.007) and healthy controls (p = 0.006). In AS patients, the serum levels of CCL11 were significantly and positively correlated with mSASSS (p = 0.006), number of syndesmophytes (p = 0.029). After adjusting for confounding factors, elevated serum levels of CCL11 were associated with increased mSASSS (β = 0.007, p = 0.03) and higher risk for the presence of syndesmophytes (OR 2.34 per 50 pg/ml increase, p = 0.012) in AS patients. We found that the serum level of CCL11 was associated with structural damage in patients with AS, suggesting that CCL11 may serve as a promising biomarker for new bone formation in AS.

Predisposition of six well-characterized microRNAs to syndesmophytes among Chinese patients with ankylosing spondylitis

OBJECTIVES

We quantified the expression of six well-characterized microRNAs (miRNAs) in peripheral blood mononuclear cells to see whether they can predispose to syndesmophytes in ankylosing spondylitis (AS) patients.

METHODS

This is a cross-sectional study involving 46 AS patients (23/23 with/without syndesmophytes) and 22 healthy controls. miRNAs expression was quantified by real-time PCR.

RESULTS

Six examined miRNAs were comparably expressed between AS patients without syndesmophytes and healthy controls (p > .05). Relative to AS patients without syndesmophytes, patients with syndesmophytes had significantly higher levels of miR-29a, miR-335-5p, miR-27a and let-7i (p = .001, .002, .013 and .029, respectively). Nine significant contributors associated with syndesmophytes in AS, including smoking, AS duration, human leukocyte antigen B27, erythrocyte sedimentation rate, C-reactive protein, miR-335-5p, miR-27a, miR-218 and sacroiliitis, were identified. The addition of miR-335-5p, miR-27a and miR-218 can significantly improve the accuracy of baseline risk factors. Based on the nine significant contributors, a nomogram was constructed, with good prediction accuracy (C-index: 0.86, p < .001).

CONCLUSION

We provide evidence for the predisposition of miR-335-5p, miR-27a and miR-218 to syndesmophytes in AS patients, indicating a contributory role of miRNAs in the pathogenesis of syndesmophytes. Further validation is warranted.

Dickkopf-1 in ankylosing spondylitis: Review and meta-analysis

BACKGROUND

Current findings regarding serum Dickkopf-1 (DKK-1) concentration in ankylosing spondylitis (AS) have proven inconsistent. This meta-analysis was performed to provide a better understanding of serum DKK-1 and AS.

METHODS

Online electronic databases were used to retrieve all relevant articles published before November 2017. The pooled standardized mean difference (SMD) with 95% confidence interval (CI) was calculated by the random-effect model.

RESULTS

23 studies, containing 1348 AS patients and 909 healthy controls, were included in this meta-analysis. No significant difference in serum DKK-1 concentration was found between AS patients and healthy controls (pooled SMD = 0.488, 95%CI = -0.176 to 1.152, p = 0.150). Subgroup analyses suggested that serum DKK-1 in patients with increased C-reactive protein (CRP) (CRP > 10 mg/L) and high modified Stroke AS Spine Score (mSASSS) (mSASSS > 30) were significantly lower than healthy controls. Serum DKK-1 was, however, increased in patients with normal CRP (CRP≤ 10 mg/L).

CONCLUSION

Although serum DKK-1 concentration was not significantly different in AS vs. healthy controls, it may be used as a biomarker of inflammation and radiographic damage in AS.

Dkk1: A key molecule in joint remodelling and fibrosis

Dickkopf-1 (Dkk-1) is a Wnt signaling pathway inhibitor that has been shown to play an important role in joint remodeling, in experimental models of arthritis and in humans. Recent data suggest that this molecule is involved in the fibrotic process as well.

Serum Sclerostin Levels in Patients with Ankylosing Spondylitis and Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

Objective. Current studies of serum sclerostin levels in AS and RA patients are inconsistent. This meta-analysis was performed to identify the association of serum sclerostin level with AS and RA patients. Methods. Embase, PubMed, MEDLINE, and Cochrane Library databases (up to 25 January 2017) were used to collect all relevant published articles. Studies were pooled and standard mean difference (SMD) with 95% confidence interval (CI) was calculated. All data analyses were performed using RevMan 5.3. Results. Totally eight studies of AS including 420 AS patients and 317 healthy controls (HC) and three studies of RA including 145 RA patients and 127 HC were finally included in this meta-analysis. The results revealed that the serum sclerostin levels in both AS patients (SMD = −0.14; 95% CI = [−0.39,0.11]; P = 0.28) and RA patients (SMD = −0.10; 95% CI = [−0.34,0.15]; P = 0.43) were not significantly different from those in HC. Conclusion. The difference of serum sclerostin levels in AS and RA patients was not significantly different from HC, indicating that the sclerostin may not associate with the development of AS and RA.

Pathogenesis of ligaments ossification in spondyloarthritis: insights and doubts

Despite intensive research in spondyloarthritis pathogenesis, some important questions still remain unanswered, particularly concerning enthesis new bone formation. Several evidences suggest that it prevalently occurs by endochondral ossification, however it remains to identify factors that can induce and influence its initiation and progression. Recent progress, achieved in animal models and in vitro and genetic association studies, has led us to hypothesize that several systemic factors (adipokines and gut hormones) and local factors (BMP and Wnt signaling) as well as angiogenesis and mechanical stress are involved. We critically review and summarize the available data and delineate the possible mechanisms involved in enthesis ossification, particularly at spinal ligament level. KEY MESSAGES Complete understanding of spondyloarthritis pathophysiology requires insights into inflammation, bone destruction and bone formation, which are all located in entheses and lead all together to ankylosis and functional disability. Several factors probably play a role in the pathogenesis of bone formation in entheses including not only cytokines but also several systemic factors such as adipokines and gut hormones, and local factors, such as BMP and Wnt signaling, as well as angiogenesis and mechanical stress. Data available about pathophysiology of new bone formation in spondyloarthritis are limited and often conflicting and future studies are needed to better delineate it and to develop new therapeutic approaches.