Serum matrix metalloproteinase 3 is an independent predictor of structural damage progression in patients with ankylosing spondylitis

Male spondyloarthritis patients and those with longer disease duration have less severe disc degeneration: propensity score-matched comparison

Objective

Using whole spine sagittal T2 MRI, we aimed to compare the severity and prevalence of disc degeneration (DD) in axial SpA patients vs the general population and to determine any association between spinal inflammation, structural changes, mobility and DD among SpA patients.

Methods

Two prospectively collected cohorts of SpA patients (n = 411) and the general population (n = 2007) were recruited. Eventually, 967 participants from the populational cohort and 304 participants from the SpA cohort were analysed. Two hundred and nineteen matched pairs were generated by propensity score matching. Imaging parameters, including Pfirrmann grading, disc herniation, high-intensity zone, Schmorl's node, Modic change and anterior marrow change were studied and compared from C2/3 to L5/S1. DD was defined as Pfirrmann grade 4 or 5. Demographic factors, including age, sex and BMI, were collected. Multivariable linear regression was used to determine the association between spinal inflammation [Spondyloarthritis Research Consortium of Canada (SPARCC) spine MRI index], structural changes [modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS)] and mobility (BASMI) with lumbar Pfirrmann score.

Results

SpA patients had lower prevalence of DD (P < 0.001). The disease stage-stratified regression model showed that SPARCC spinal MRI index was associated with higher lumbar Pfirrmann scores in early disease (β = 0.196, P = 0.044), whereas mSASSS was associated with lower lumbar Pfirrmann scores in later disease (β = -0.138, P = 0.038). Males had higher mSASSS (P < 0.001) and lower odds of whole spine DD (odds ratio = 0.622, P = 0.028).

Conclusion

SpA patients had lower DD severity than the general population. Males had higher mSASSSs, and increased mSASSS at later disease was associated with less severe DD.

Rapid screening for autoimmune diseases using Fourier transform infrared spectroscopy and deep learning algorithms

Introduce

Ankylosing spondylitis (AS), rheumatoid arthritis (RA), and osteoarthritis (OA) are three rheumatic immune diseases with many common characteristics. If left untreated, they can lead to joint destruction and functional limitation, and in severe cases, they can cause lifelong disability and even death. Studies have shown that early diagnosis and treatment are key to improving patient outcomes. Therefore, a rapid and accurate method for rapid diagnosis of diseases has been established, which is of great clinical significance for realizing early diagnosis of diseases and improving patient prognosis.

Methods

This study was based on Fourier transform infrared spectroscopy (FTIR) combined with a deep learning model to achieve non-invasive, rapid, and accurate differentiation of AS, RA, OA, and healthy control group. In the experiment, 320 serum samples were collected, 80 in each group. AlexNet, ResNet, MSCNN, and MSResNet diagnostic models were established by using a machine learning algorithm.

Result

The range of spectral wave number measured by four sets of Fourier transform infrared spectroscopy is 700-4000 cm-1. Serum spectral characteristic peaks were mainly at 1641 cm-1(amide I), 1542 cm-1(amide II), 3280 cm-1(amide A), 1420 cm-1(proline and tryptophan), 1245 cm-1(amide III), 1078 cm-1(carbohydrate region). And 2940 cm-1 (mainly fatty acids and cholesterol). At the same time, AlexNet, ResNet, MSCNN, and MSResNet diagnostic models are established by using machine learning algorithms. The multi-scale MSResNet classification model combined with residual blocks can use convolution modules of different scales to extract different scale features and use resblocks to solve the problem of network degradation, reduce the interference of spectral measurement noise, and enhance the generalization ability of the network model. By comparing the experimental results of the other three models AlexNet, ResNet, and MSCNN, it is found that the MSResNet model has the best diagnostic performance and the accuracy rate is 0.87.

Conclusion

The results prove the feasibility of serum Fourier transform infrared spectroscopy combined with a deep learning algorithm to distinguish AS, RA, OA, and healthy control group, which can be used as an effective auxiliary diagnostic method for these rheumatic immune diseases.

PRICKLE1 gene methylation and abnormal transcription in Chinese patients with ankylosing spondylitis

BACKGROUND

Ankylosing spondylitis (AS) is a common inflammatory arthritis without a reliable biomarker. The role of methylation and mRNA expression of PRICKLE1 promoter in the pathogenesis of ankylosing spondylitis remains unclear.

METHODS

A two-stage case-control design was used to detect the characteristics of methyl group and transcriptome of PRICKLE1 gene in Ankylosing spondylitis. The methylation degree of PRICKLE1 gene promoter region was tested by phosphate-sequencing, and further analyzed whether there was significant difference in methylation level of PRICKLE1 gene. The expression levels of PRICKLE1 mRNA in 50 AS patients and 50 healthy controls were detected by real-time quantitative PCR (RT-qPCR).

RESULTS

Compared with healthy control group, the intensity of methylation in 4 ponds of PRICKLE1 in patients with Ankylosing spondylitis was low, and the mRNA levels were overexpressed (P = 0.017). ROC results showed that the sensitivity of PRICKLE1 was 68.67% and specificity was 71.43%.

CONCLUSION

There is a significant change in the concentration of serum PRICKLE1 mRNA​in patients with Ankylosing spondylitis, and the degree of gene methylation is significantly reduced, suggesting that PRICKLE1 gene maybe involved in the pathogenesis of Ankylosing spondylitis, which may be useful for predicting the occurrence of AS and finding new early screening indicators.

Matrix Metalloproteinases; A Biomarker of Disease Activity and Prognosis in Spondyloarthritis: A Narrative Review

BACKGROUND

Matrix metalloproteinases, as components of the proteolytic system, are deemed to be implicated in the pathogenesis and progression of several rheumatic diseases. Their role in spondyloarthritis has been investigated by several studies.

OBJECTIVE

This article aims to review and summarize the current knowledge related to metalloproteinases in patients with spondyloarthritis.

METHODS

To examine the association between matrix metalloproteinases and spondyloarthritis, we conducted a narrative review using a literature search in SCOPUS for English-language sources. The search included studies published from the database inception to December 2020.

RESULTS

A total number of 74 articles were included. It was found that levels of matrix metalloproteinases 3 were higher in radiographic axial spondyloarthritis patients and seemed to play a role in the progression of joint damage. The levels of matrix metalloproteinases 1, 2, and 9 were upregulated in psoriatic arthritis patients compared to psoriasis and could identify psoriasis patients who would develop rheumatic manifestations. The levels of matrix metalloproteinases correlated significantly with disease activity in ankylosing spondylitis and decreased upon treatment with Tumor Necrosis Factor inhibitors (TNFi).

CONCLUSION

Excessive matrix metalloproteinases activity is associated with articular destruction. Their levels can reflect disease activity, structural damage, and response to TNFi in patients with spondyloarthritis. Nevertheless, further studies are needed to confirm these results.

Identification of diagnostic mRNA biomarkers in whole blood for ankylosing spondylitis using WGCNA and machine learning feature selection

Ankylosing spondylitis (AS) is a common inflammatory spondyloarthritis affecting the spine and sacroiliac joint that finally results in sclerosis of the axial skeleton. Aside from human leukocyte antigen B27, transcriptomic biomarkers in blood for AS diagnosis still remain unknown. Hence, this study aimed to investigate credible AS-specific mRNA biomarkers from the whole blood of AS patients by analyzing an mRNA expression profile (GSE73754) downloaded Gene Expression Omnibus, which includes AS and healthy control blood samples. Weighted gene co-expression network analysis was performed and revealed three mRNA modules associated with AS. By performing gene set enrichment analysis, the functional annotations of these modules revealed immune biological processes that occur in AS. Several feature mRNAs were identified by analyzing the hubs of the protein-protein interaction network, which was based on the intersection between differentially expressed mRNAs and mRNA modules. A machine learning-based feature selection method, SVM-RFE, was used to further screen out 13 key feature mRNAs. After verifying by qPCR, IL17RA, Sqstm1, Picalm, Eif4e, Srrt, Lrrfip1, Synj1 and Cxcr6 were found to be significant for AS diagnosis. Among them, Cxcr6, IL17RA and Lrrfip1 were correlated with severity of AS symptoms. In conclusion, our findings provide a framework for identifying the key mRNAs in whole blood of AS that is conducive for the development of novel diagnostic markers for AS.

Effects of targeted therapies on bone in rheumatic and musculoskeletal diseases

Generalized bone loss (osteoporosis) and fragility fractures can occur in rheumatic and musculoskeletal diseases including rheumatoid arthritis and spondyloarthritis (SpA; including ankylosing spondylitis and psoriatic arthritis). In addition, rheumatoid arthritis can involve localized, periarticular bone erosion and, in SpA, local (pathological) bone formation can occur. The RANK-RANKL-osteoprotegerin axis and the Wnt-β-catenin signalling pathway (along with its inhibitors sclerostin and Dickkopf 1) have been implicated in inflammatory bone loss and formation, respectively. Targeted therapies including biologic DMARDs and Janus kinase (JAK) inhibitors can stabilize bone turnover and inhibit radiographic joint damage, and potentially also prevent generalized bone loss. Targeted therapies interfere at various points in the mechanisms of local and generalized bone changes in systemic rheumatic diseases, and they effect biomarkers of bone resorption and formation, bone mass and risk of fragility fractures. Studies on the effects of targeted therapies on rates of fragility fracture are scarce. The efficacy of biologic DMARDs for arresting bone formation in axial SpA is debated. Improved understanding of the most relevant therapeutic targets and identification of important targeted therapies could lead to the preservation of bone in inflammatory rheumatic and musculoskeletal diseases.

Serum RANKL levels in Chinese patients with ankylosing spondylitis: a meta-analysis

Objective

We aimed to determine the association between serum receptor activator of nuclear factor-kappa B ligand (sRANKL) levels and ankylosing spondylitis (AS) in Chinese patients.

Methods

The PubMed, Cochrane Library, Embase, Chinese Biomedical Database, Web of Science, China National Knowledge Infrastructure, VIP, and Wan Fang databases were searched for studies conducted before October 1, 2020, without language restrictions. STATA version 12.0 and Revman version 5.3 were used to analyze the data. The standard mean differences (SMDs) and corresponding 95% confidence intervals (95% CIs) were calculated.

Results

Twelve clinical case–control studies, including 585 patients with AS and 423 healthy controls, were included. The combined SMD for sRANKL suggested that the sRANKL level was significantly higher in Chinese patients with AS than in healthy controls (SMD: 3.27, 95% CI 2.11–4.43, P < 0.00001). Serum RANKL-related factor osteoprotegerin (OPG) levels (SMD: 0.86, 95% CI 0.09–1.64, P < 0.03) were lower in the Chinese patients with AS than in healthy controls, and the RANKL/OPG ratio (SMD = 1.05, 95% CI 0.64–1.46, P < 0.00001) in Chinese patients with AS was approximately the same as that of healthy controls. Subgroup analysis indicated that patients from North and South China had higher sRANKL levels than controls; the sRANKL levels of patients from South China were higher in the subgroup with a Bath Ankylosing Spondylitis Functional Index (BASFI) of > 4 than those of patients in other subgroups. In terms of duration, patients with AS for > 8 years had higher sRANKL levels than health controls. Other subgroup analyses were conducted by region, language, source of control, age, and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). In these subgroups, the sRANKL levels were significantly higher in the patients with AS than in healthy controls. The BASFI and BASDAI were sources of heterogeneity.

Conclusions

The sRANKL levels are higher in Chinese patients with AS, especially among those from South China. sRANKL levels may be positively correlated with the pathogenesis of AS among Chinese patients.

Similarities and Differences Between Juvenile and Adult Spondyloarthropathies

Spondyloarthritis (SpA) encompasses a broad spectrum of conditions occurring from childhood to middle age. Key features of SpA include axial and peripheral arthritis, enthesitis, extra-articular manifestations, and a strong association with HLA-B27. These features are common across the ages but there are important differences between juvenile and adult onset disease. Juvenile SpA predominantly affects the peripheral joints and the incidence of axial arthritis increases with age. Enthesitis is important in early disease. This review article highlights the similarities and differences between juvenile and adult SpA including classification, pathogenesis, clinical features, imaging, therapeutic strategies, and disease outcomes. In addition, the impact of the biological transition from childhood to adulthood is explored including the importance of musculoskeletal and immunological maturation. We discuss how the changes associated with adolescence may be important in explaining age-related differences in the clinical phenotype between juvenile and adult SpA and their implications for the treatment of juvenile SpA.

Elevated serum level of hepatocyte growth factor predicts development of new syndesmophytes in men with ankylosing spondylitis

Objectives

To study baseline serum hepatocyte growth factor (s-HGF) as a predictor of spinal radiographic progression overall and by sex and to analyse factors correlated to changes in s-HGF in patients with AS.

Methods

At baseline and the 5-year follow-up, s-HGF was analysed with ELISA. Spinal radiographs were graded according to modified Stoke Ankylosing Spondylitis Spinal Score. Radiographic progression was defined as ≥2 modified Stoke Ankylosing Spondylitis Spinal Score units/5 years or development of ≥1 syndesmophyte. Logistic regression analyses were used.

Results

Of 204 baseline participants, 163 (80%) completed all examinations at the 5-year follow-up (54% men). Baseline s-HGF was significantly higher in men who developed ≥1 syndesmophyte compared with non-progressors, median (interquartile range) baseline s-HGF 1551 (1449–1898) vs 1436 (1200–1569) pg/ml, P = 0.003. The calculated optimal cut-off point for baseline s-HGF ≥1520 pg/ml showed a sensitivity of 70%, a specificity of 69% and univariate odds radio (95% CI) of 5.25 (1.69, 14.10) as predictor of development of ≥1 new syndesmophyte in men. Baseline s-HGF ≥1520 pg/ml remained significantly associated with development of ≥1 new syndesmophyte in men in an analysis adjusted for the baseline variables age, smoking, presence of syndesmophytes and CRP, odds radio 3.97 (1.36, 11.60). In women, no association with HGF and radiographic progression was found. Changes in s-HGF were positively correlated with changes in ESR and CRP.

Conclusion

In this prospective cohort study elevated s-HGF was shown to be associated with development of new syndesmophytes in men with AS.

Autoantibodies against Protein Phosphatase Magnesium-Dependent 1A as a Biomarker for Predicting Radiographic Progression in Ankylosing Spondylitis Treated with Anti-Tumor Necrosis Factor Agents

BACKGROUND

Patients with ankylosing spondylitis (AS) have increased levels of protein phosphatase magnesium-dependent 1A (PPM1A) and autoantibodies. We evaluated the usefulness of serum anti-PPM1A antibodies as a biomarker for AS.

METHODS

Serum samples from 58 AS patients were obtained from a multicenter registry prior to the initiation of anti-TNF agents. The serum levels of anti-PPM1A antibodies were measured using ELISA. Spinal radiographic progression was defined as an increase in the modified stoke ankylosing spondylitis spinal score (mSASSS) by ≥2 units or a newly developed syndesmophyte. The role of exogenous PPM1A on bone mineralization was evaluated using primary osteoprogenitors acquired from patients with AS and non-inflammatory controls.

RESULTS

The baseline levels of anti-PPM1A antibodies and mSASSS were higher in the radiographic progression group than in the non-progression group. In logistic regression analysis, baseline mSASSS and serum anti-PPM1A antibodies were associated with a higher risk of progression. The level of anti-PPM1A antibodies for predicting progression had an AUC of 0.716 (cut-off value: 43.77 ng/mL). PPM1A stimulation increased matrix mineralization in AS-osteoprogenitors but not in controls.

CONCLUSION

Along with mSASSS, the serum levels of anti-PPM1A antibodies might be useful as a predictor of radiographic progression after treatment with anti-TNF agents.

Biomarker development for axial spondyloarthritis

The term axial spondyloarthritis (axSpA) encompasses a heterogeneous group of diseases that have variable presentations, extra-articular manifestations and clinical outcomes, and that will respond differently to treatments. The prototypical type of axSpA, ankylosing spondylitis, is thought to be caused by interaction between the genetically primed host immune system and gut microbiota. Currently used biomarkers such as HLA-B27 status, C-reactive protein and erythrocyte sedimentation rate have, at best, moderate diagnostic and predictive value. Improved biomarkers are needed for axSpA to assist with early diagnosis and to better predict treatment responses and long-term outcomes. Advances in a range of 'omics' technologies and statistical approaches, including genomics approaches (such as polygenic risk scores), microbiome profiling and, potentially, transcriptomic, proteomic and metabolomic profiling, are making it possible for more informative biomarker sets to be developed for use in such clinical applications. Future developments in this field will probably involve combinations of biomarkers that require novel statistical approaches to analyse and to produce easy to interpret metrics for clinical application. Large publicly available datasets from well-characterized case-cohort studies that use extensive biological sampling, particularly focusing on early disease and responses to medications, are required to establish successful biomarker discovery and validation programmes.

An update on serum biomarkers to assess axial spondyloarthritis and to guide treatment decision

Axial spondyloarthritis (axSpA) is a group of debilitating, chronic, rheumatic conditions characterized by inflammation and new bone formation, mainly involving the spine and the sacroiliac joints. The lack of biomarkers in axSpA is well known. Despite significant treatment advances in recent years thanks to the introduction of drugs with a new mode of action, such as new biologic and targeted synthetic disease-modifying antirheumatic drugs, no relevant improvement in the identification of disease biomarkers has been achieved. Common parameters, such as erythrocyte sedimentation rate and C-reactive protein, which are routinely used to measure systemic inflammation, are the sole markers available to date and are not adequate to assess disease activity in all patients. The aim of this study is to review the most promising serum biomarkers that may help treatment decision in axSpA via a proper assessment of disease activity and identification of negative prognostic factors.

Added value of biomarkers compared with clinical parameters for the prediction of radiographic spinal progression in axial spondyloarthritis

OBJECTIVES

The objective of this study was to examine whether adding biomarkers to routine clinical parameters improves prediction of radiographic spinal progression in axial spondyloarthritis.

METHODS

One hundred and seventeen patients with ankylosing spondylitis who completed the Effects of NSAIDs on RAdiographic Damage in Ankylosing Spondylitis (ENRADAS) trial were included. Radiographic spinal progression was defined as worsening of the modified Stoke Ankylosing Spondylitis Spine Score by ⩾2 points after 2 years. A clinical prediction model was constructed out of baseline syndesmophytes, elevated CRP, cigarette smoking and male sex. The following serum biomarkers were measured at baseline by ELISA: MMP3, VEGF, calprotectin, leptin, high molecular weight adiponectin, osteoprotegerin, sclerostin, N-terminal telopeptide, procollagen type II N-terminal propeptide and serum amyloid A.

RESULTS

Repeated cross-validation analyses revealed one biomarker combination with potential added predictive value in addition to the clinical model: leptin + high molecular weight adiponectin + VEGF. This biomarker combination showed an area under the curve (AUC)Biomarkers = 0.731 (95% CI: 0.614, 0.848), which was numerically superior to the clinical model [AUCClinical = 0.665 (95% CI: 0.553, 0.776)]. A combination of clinical parameters + biomarkers showed an improved predictive value compared with the clinical model reflected by AUCClinical+Biomarkers = 0.768 (95% CI: 0.666, 0.871), though not statistically significant (P = 0.051). However, by considering the part of the receiver operating characteristic curve with a specificity ⩾75% resulting in partial AUC (pAUC), the improvement becomes significant (pAUCClinical+Biomarkers = 0.119; pAUCClinical = 0.053; P = 0.01).

CONCLUSION

Biomarkers show potential to improve the prediction of radiographic spinal progression in axial spondyloarthritis when used in addition to the clinical parameters, though the added value seems to be rather small.

Serological Biomarkers in Early Axial Spondyloarthritis During 24-Months Follow Up (Italian Arm of Space Study)

Objectives: The study aimed to evaluate biomarkers facilitating early axial-spondyloarthritis (axSpA) diagnosis and disease activity and imaging indices correlated. Materials and Methods: Seventy-five patients with low back pain (LBP) (≥3 months, ≤2 years, onset ≤45 years) participating in the Italian arm of the SpondyloArthritis-Caught-Early (SPACE) study underwent a physical examination, questionnaires, laboratory tests, spine, and sacroiliac joints (SIJ) X-rays and magnetic resonance imaging (MRI) at baseline and during a 24-months follow-up. Two expert rheumatologists formulated axSpA diagnosis and assessed fulfillment of Assessment of SpondyloArthritis International Society (ASAS) criteria. Disease activity and physical functioning were assessed using imaging, clinical, and serological indices. Spine and SIJ MRI and X-rays were scored independently by 2 readers following the Spondyloarthritis Research Consortium of Canada (SPARCC), mSASSS, and mNY-criteria. Patients were classified in accordance to ASAS criteria as: 21 patients classified according to axSpA imaging arm; 29 patients classified according to axSpA clinical ± imaging arm; 25 patients not fulfilling ASAS criteria. Results: At baseline biomarker levels were not significantly increased in any of the patient groups. Instead, a significant decrease of all functional and disease activity indices from baseline to 24 months was observed in all the three groups. In the same period, there were no significant variation in the serological markers values within each group. The correlations between IL-17 and IL-23 and clinical and functional indices were not significant. On the other hand, significant correlations were found between IL-22 and Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Patient Global Score (BASG1), Health Assessment Questionnaire (HAQ), Visual Analog Scale (VAS pain); MMP3 and mSASSS; MMP3 and hsCRP. Conclusions: Although not significantly higher in any of the cohorts, IL-22, MMP3, and hsCRP values correlated with some disease activity indices and with mSASSS. Further studies are warranted to confirm these preliminary findings.

Metabolites of type I, II, III, and IV collagen may serve as markers of disease activity in axial spondyloarthritis

Local inflammation in axial spondyloarthritis (axSpA) leads to the release of collagen metabolites from the disease-affected tissue. We investigated whether collagen metabolites were associated with disease activity and could distinguish non-radiographic(nr)-axSpA from ankylosing spondylitis (AS). A total of 193 axSpA patients (nr-axSpA, n = 121 and AS, n = 72) and asymptomatic controls (n = 100) were included. Serum levels of metalloproteinase (MMP)-degraded collagen type I (C1M), type II (C2M), type III (C3M) and type IV (C4M2) were quantified by enzyme-linked immunosorbent assay (ELISA). All metabolites were higher in axSpA than in controls (all p < 0.001). Serum levels of C1M, C3M, and C4M2 were increased in AS compared to nr-axSpA (43.4 ng/mL vs. 34.6; p < 0.001, 15.4 vs. 12.8; p = 0.001, and 27.8 vs. 22.4; p < 0.001). The best metabolite to differentiate between axSpA and controls was C3M (AUC 0.95; specificity 92.0, sensitivity 83.4). C1M correlated with ASDAS-CRP in nr-axSpA (ρ = 0.37; p < 0.001) and AS (ρ = 0.57; p < 0.001). C1M, C3M, and C4M2 were associated with ASDAS-CRP in AS and nr-axSpA after adjustment for age, gender, and disease duration. Serum levels of collagen metabolites were significantly higher in AS and nr-axSpA than in controls. Moreover, the present study indicates that collagen metabolites reflect disease activity and are useful biomarkers of axSpA.

Physiologic facet capsule stretch can induce pain & upregulate matrix metalloproteinase-3 in the dorsal root ganglia when preceded by a physiological mechanical or nonpainful chemical exposure

BACKGROUND

Neck pain from cervical facet loading is common and induces inflammation and upregulation of nerve growth factor (NGF) that can sensitize the joint afferents. Yet, the mechanisms by which these occur and whether afferents can be pre-conditioned by certain nonpainful stimuli are unknown. This study tested the hypothesis that a nonpainful mechanical or chemical insult predisposes a facet joint to generate pain after a later exposure to typically nonpainful distraction.

METHODS

Rats were exposed to either a nonpainful distraction or an intra-articular subthreshold dose of NGF followed by a nonpainful distraction two days later. Mechanical hyperalgesia was measured daily and C6 dorsal root ganglia (DRG) tissue was assayed for NGF and matrix metalloproteinase-3 (MMP-3) expression on day 7.

FINDINGS

The second distraction increased joint displacement and strains compared to its first application (p = 0.0011). None of the initial exposures altered behavioral sensitivity in either of the groups being pre-conditioned or in controls; but, sensitivity was established in both groups receiving a second distraction within one day that lasted until day 7 (p < 0.024). NGF expression in the DRG was increased in both groups undergoing a pre-conditioning exposure (p < 0.0232). Similar findings were observed for MMP-3 expression, with a pre-conditioning exposure increasing levels after an otherwise nonpainful facet distraction.

INTERPRETATION

These findings suggest that nonpainful insults to the facet joint, when combined, can generate painful outcomes, possibly mediated by upregulation of MMP-3 and mature NGF.

Role of oral flora in chemotherapy-induced oral mucositis in vivo

OBJECTIVE

To determine if commensal oral microflora impacts the severity of chemotherapy-induced oral mucositis (OM).

DESIGN

Specific-pathogen-free (SPF) and germ-free Swiss Webster mice in the experimental groups were dosed with 5-fluorouracil (5-FU) to induce OM. Mice in the control group received phosphate buffered saline. Comparative analyses of the epithelial thickness and cell proliferation/turnover rates, as well as the expression levels of metalloproteinases and pro-inflammatory mediators in the oral mucosa between the control and experimental groups were determined by histopathological and immunohistochemical analyses.

RESULTS

5-FU-treated SPF and germ-free mice showed characteristic features of OM with reduced oral epithelial thickness, presence of inflammatory cells in the connective tissues, and increased levels of expression of metalloproteinases and pro-inflammatory cytokines compared to the respective control groups. When 5-FU-treated SPF and germ-free mice were compared, 5-FU-treated germ-free mice exhibited less severe epithelial destruction with higher expression of the cell proliferation marker Ki67, coupled with lower expression levels of metalloproteinases and pro-inflammatory cytokine in the oral mucosa.

CONCLUSION

This study provides the first histopathological evidence that oral flora has a detrimental effect on chemotherapy-induced OM in vivo.

Inhibition of CXCR4 inhibits the proliferation and osteogenic potential of fibroblasts from ankylosing spondylitis via the Wnt/β‑catenin pathway

Ankylosing spondylitis (AS) is an autoimmune condition characterized by chronic inflammation and abnormal ossification as the primary features of the disease. The aim of the present study was to investigate the role of C‑X‑C chemokine receptor type 4 (CXCR4) in ossification from patients with AS. CXCR4 expression was assessed by western blot analysis and immunohistochemistry analysis of tissues obtained from patients with AS and controls. Fibroblasts were isolated, cultured and incubated with AMD 3100 and stromal cell‑derived factor‑1 to inhibit and promote CXCR4 levels, respectively. CXCR4 was upregulated in hip synovial tissues from patients with AS compared with that observed in controls. AS fibroblasts exhibited increased proliferation and growth rates. Inhibition of CXCR4 increased the phosphorylation of β‑catenin and downregulated the expression of β‑catenin, v‑myc avian myelocytomatosis viral oncogene homolog, cyclin D1 and osteocalcin. Alizarin red staining demonstrated a decrease in biomineralization activity following the inhibition of CXCR4. These data support the hypothesis that inhibiting CXCR4 in patients with AS may suppress the ossification of fibroblasts.

Unmet Needs in Axial Spondyloarthritis

During the past decade, the well-known disease called ankylosing spondylitis has come to be considered as a subset of the broader entity referred as axial spondyloarthritis (axSpA), which also includes non-radiographic axSpA. The need of this new classification was aimed to improve the sensitivity for an early diagnosis, to reduce diagnostic delay, and to allow an early treatment. Although there is improvement in the recognition, the management of patients, and the treatment strategies of axSpA, unmet needs persist. There is still a substantial gap of 5-8 years between the onset of symptoms and the diagnosis of axSpA and, even in patients diagnosed early, 20-40% of them do not respond or have a loss of response to anti-TNF treatment. Moreover, the pathogenesis of the disease and, in particular, the mechanisms of new bone formation are far to be completely understood. Nevertheless, the discovery of IL-23/IL-17 axis with the development of biologic inhibitors, the identification of new subsets of effector cells, together with the interest in the detection of potential biomarkers of bone formation brought the approach to axSpA into a new era. This review is intended to enhance awareness and understanding of axSpA and to identify and discuss the current unmet needs in axSpA, including diagnosis, classification, biomarkers, pathogenesis, management, and treatment strategies.

Hepatocyte growth factor is a potential biomarker for osteoproliferation and osteoporosis in ankylosing spondylitis

We explored relations between serum hepatocyte growth factor (HGF), disease activity, osteoproliferation, and bone mineral density (BMD) in ankylosing spondylitis (AS), in comparison with healthy controls. HGF was increased especially in male AS patients and smokers and associated with both lower BMD and more chronic radiographic changes in the spine.

INTRODUCTION

Ankylosing spondylitis (AS) is characterized by both osteoproliferation and increased bone loss. Biomarkers are requested to predict the processes. The aims of this study were to compare serum levels of hepatocyte growth factor (HGF), matrix metalloproteinase-3 (MMP-3), and vascular endothelial growth factor (VEGF) in AS patients with healthy controls (HC) and to explore the associations with disease activity, osteoproliferation, and bone mineral density (BMD).

METHODS

Serum from AS patients (modified NY-criteria) and HC was analyzed for HGF, MMP-3, and VEGF with ELISA. Disease activity parameters were collected. Osteoproliferation was assessed with modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) and BMD was measured in femoral neck.

RESULTS

Totally, 204 AS patients and 80 sex and age matched HC were included. Serum HGF was higher in the AS patients compared with the HC, whereas serum MMP-3 and VEGF were not. Serum HGF was also higher in smokers and in the male AS patients positively correlated with age, BASMI, and mSASSS, and negatively correlated with BMD. The biomarkers were all positively associated with ESR, CRP, and WBC. In multiple linear regression analysis serum HGF remained associated with higher mSASSS and lower BMD, after adjusting for age, sex, CRP, smoking, and body mass index.

CONCLUSIONS

Serum HGF was increased in male AS patients and associated with higher mSASSS and lower BMD. In addition, serum HGF was positively associated with risk factors for osteoproliferation such as age, CRP and smoking. HGF could be a potential biomarker of importance for the bone metabolism in AS.

TRIAL REGISTRATION

NCT00858819.

Resveratrol displays anti-inflammatory properties in an ex vivo model of immune mediated inflammatory arthritis

Background

Resveratrol is a natural polyphenol found in berries, roots and wine that is well known to have anti-inflammatory and anti-oxidative properties. The anti-inflammatory effect has been reported for both immune cells and connective tissues, but only few studies have investigated effects on immune mediated inflammatory arthritis. None of which have studied this effect when combining resveratrol with methotrexate or adalimumab, two major drugs in the treatment of immune mediated inflammatory arthritis.

We therefore aimed to investigate the anti-inflammatory effect of resveratrol alone and in combination with methotrexate or adalimumab in ex vivo models of immune mediated inflammatory arthritis. We furthermore aimed to describe any variations in this effect based on disease activity and cellular composition of the synovial fluid infiltrate.

Methods

Synovial fluid mononuclear cells from patients with rheumatoid arthritis (n = 7) and spondyloarthritis (n = 7) were cultured for either 48 h or 21 days. In both models, synovial fluid mononuclear cells were treated with resveratrol alone or in combination with methotrexate or adalimumab. Monocyte chemoattractant protein 1, matrix metalloproteinase 3 and tartrate resistant acidic phosphatase were measured to quantify inflammation, enzymatic degradation and osteoclast differentiation, respectively.

Results

Resveratrol reduced monocyte chemoattractant protein 1 production by synovial fluid mononuclear cells significantly (p = 0.005) compared to untreated controls. The effect of resveratrol was greatest in cultures from patients with low disease activity, i.e. DAS28CRP ≤ 3.2 (p = 0.022), and in cultures dominated by lymphocytes (p = 0.03). Further, the combination of methotrexate and resveratrol significantly reduced monocyte chemoattractant protein 1 levels compared with methotrexate alone in cultures from patients with low disease activity (p = 0.016), and in cultures with high lymphocyte count (p = 0.011). Resveratrol did not significantly affect matrix metalloproteinase 3 and tartrate resistant acidic phosphatase production.

Conclusion

Resveratrol has anti-inflammatory properties in our ex vivo model of immune mediated inflammatory arthritis. Results show an additive effect of resveratrol, when combined with methotrexate in samples dominated by lymphocytes and samples from patients with low disease activity. This suggests further investigations in vitro and whether this effect may also be present in a clinical setting.

Electronic supplementary material

The online version of this article (10.1186/s41927-018-0036-5) contains supplementary material, which is available to authorized users.

MMP-8 single-nucleotide polymorphisms are related to ankylosing spondylitis in Chinese Han population

Ankylosing spondylitis (AS) is an extreme form of inflammatory arthritis which always leads to bony fusion of vertebral and chronic pain of back. A lot of genes including interleukin, matrix metalloproteinases (MMPs), and endoplasmic reticulum aminopeptidase were found associated with AS. MMP family members were involved in the autoimmune disease and orthopedic diseases such as rheumatoid arthritis and osteoarthritis, while few studies concentrated on the correlation between single-nucleotide polymorphisms (SNPs) in MMP and AS. In addition, there is no report on the relationship between MMP-8 and AS. To investigate the association between SNPs in MMP-8 and AS, we recruited 268 patients with AS and 654 healthy people to conduct a case-control study. Five SNPs including rs3740938, rs2012390, rs1940475, rs11225394, and rs11225395 of MMP-8 gene were genotyped. It was found rs3740938 of MMP-8 was associated with an increased risk of AS under the dominant model and additive model after adjustment for gender and age by performing logistic regression analysis (odds ratio [OR] = 1.49, 95% confidence interval [CI] = 1.02-2.18, P = .038; OR = 1.37, 95% CI = 1.01-1.87, P = .042, respectively). Moreover, haplotype "GGTCA" was associated with an increased risk of AS without adjustment for age and gender (OR = 1.75, 95% CI = 1.05-2.92, P = .032), while no positive result was found after adjustment for age and gender. Based on our results, our study indicates significant association between SNPs of MMP-8 and AS risk in a Chinese Han population and these results provide the first evidence that MMP-8 is correlated with AS.

Functional relevance of radiographic spinal progression in axial spondyloarthritis: results from the GErman SPondyloarthritis Inception Cohort

Objectives

The aim of the study was to investigate the functional relevance of the development of structural damage in the spine in patients with early axial spondyloarthritis (axSpA).

Methods

Altogether, 210 patients with early axSpA (symptom duration ⩽10 years) who completed a 2-year clinical and radiographic follow-up in the GErman SPondyloarthritis Inception Cohort were included. An association between structural damage in the spine [modified Stoke AS Spine Score (mSASSS)] and functional status (the BASFI) or spinal mobility (the BASMI) was assessed in a longitudinal linear mixed model analysis; both unstandardized (β) and standardized (βstand) regression coefficients were calculated.

Results

There was an association between mSASSS and BASFI: β = 0.05 (95% CI: 0.03, 0.08) and βstand = 0.20 (95% CI: 0.11, 0.59) adjusted for disease activity parameters (the BASDAI and CRP), the presence of definite radiographic sacroiliitis and sex. An association between mSASSS and BASMI was stronger: β = 0.08 (95% CI: 0.05, 0.11) and βstand = 0.41 (95% CI: 0.25, 0.57) adjusted for the same parameters. These data indicate that, over time, an increase of 20 or 12 mSASSS points would be responsible for an increase of one BASFI or one BASMI point, respectively. Disease activity (BASDAI) also showed a significant association with BASFI [β = 0.79 (95% CI: 0.71, 0.86) and βstand = 0.71 (95% CI: 0.63, 0.77)] and BASMI [β = 0.22 (95% CI: 0.15, 0.30) and βstand = 0.28 (95% CI: 0.18, 0.37)].

Conclusion

Structural damage in the spine and disease activity are both determinants of the functional status and spinal mobility in early axSpA.

Axial spondyloarthritis

The term axial spondyloarthritis covers both patients with non-radiographic and radiographic axial spondyloarthritis, which is also termed ankylosing spondylitis. The disease usually starts in the third decade of life with a male to female ratio of two to one for radiographic axial spondyloarthritis and of one to one for non-radiographic axial spondyloarthritis. More than 90% heritabilty has been estimated, the highest genetic association being with HLA-B27. The pathogenic role of HLA-B27 is still not clear although various hypotheses are available. On the basis of evidence from trials the cytokines tumour necrosis factor (TNF)-α and interleukin-17 appear to have a relevant role in pathogenesis. The mechanisms of interaction between inflammation and new bone formation is still not completely understood but clarification will be important for the prevention of long-term structural damage of the bone. The development of new criteria for classification and for screening of patients with axial spondyloarthritis have been crucial for the early indentification and treatment of such patients, with MRI being the most important existing imaging method. Non-steroidal anti-inflammatory drugs and TNF blockers are effective therapies. Blockade of interleukin-17 is a new and relevant treatment option.

Serum levels of leptin and high molecular weight adiponectin are inversely associated with radiographic spinal progression in patients with ankylosing spondylitis: results from the ENRADAS trial

Background

Previous research indicates a role of adipokines in inflammation and osteogenesis. Hence adipokines might also have a pathophysiological role in inflammation and new bone formation in patients with ankylosing spondylitis (AS). The aim of this study was to investigate the role of adipokine serum levels as predictors of radiographic spinal progression in patients with AS.

Methods

A total of 120 patients with definite AS who completed a 2-year follow up in the ENRADAS trial were included in the current study. Radiographic spinal progression was defined as: (1) worsening of the modified Stoke Ankylosing Spondylitis spine (mSASSS) score by ≥2 points and/or (2) new syndesmophyte formation or progression of existing syndesmophytes after 2 years. Serum levels of adipokines (adiponectin (APN) and its high molecular weight form (HMW-APN), chemerin, leptin, lipocalin-2, omentin, resistin, visfatin) were measured using enzyme-linked immunosorbent assays.

Results

There was a significant association between radiographic spinal progression and both leptin and HMW-APN. Baseline serum levels of both adipokines were lower in patients who showed radiographic spinal progression after 2 years. This association was especially evident in men; they had generally lower leptin and HMW-APN serum levels as compared to women. The inverse association between adipokines and radiographic spinal progression was confirmed in the logistic regression analysis: the odds ratios (OR) for the outcome “no mSASSS progression ≥2 points” were 1.16 (95% CI 1.03 to 1.29) and 1.17 (95% CI 0.99 to 1.38), for leptin and HMW-APN, respectively; for “no syndesmophyte formation/progression” the respective OR were 1.29 (95% CI 1.11 to 1.50) and 1.18 (95% CI 0.98 to 1.42), adjusted for the presence of syndesmophytes at baseline, C-reactive protein at baseline, sex, body mass index (BMI), non-steroidal anti-inflammatory drugs intake score over 2 years, and smoking status at baseline.

Conclusion

Serum leptin and HMW-APN predict protection from spinal radiographic progression in patients with AS. Women generally have higher leptin and HMW-APN serum levels that might explain why they have less structural damage in the spine as compared to male patients with AS.

Trial registration

EudraCT: 2007-007637-39. ClinicalTrials.gov, NCT00715091. Registered on 14 July 2008.

Matrix Metalloproteinases and Synovial Joint Pathology

Matrix metalloproteinases (MMPs) are zinc-dependent enzymes. These enzymes play a critical role in the destruction of articular cartilage in rheumatoid arthritis (RA), osteoarthritis (OA), psoriatic arthritis (PsA), and the spondyloarthropathies. MMP gene expression is upregulated in these synovial joint pathologies in response to elevated levels of proinflammatory cytokines and soluble mediators such as tumor necrosis factor-α, interleukin-1 (IL-1), IL-6, IL-17, and interferon-γ. These molecules are capable of activating the mitogen-activated protein kinase and Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathways by binding the cytokine to their respective receptors on immune cells, macrophages, chondrocytes, synoviocytes, and osteocytes leading to increased synthesis of MMPs. Biologic drugs and/or small-molecule inhibitors designed to block cytokine to cytokine receptor interactions or to selectively inhibit JAKs have clinical efficacy in RA, PsA, and ankylosing spondylitis which correlated with a reduction in MMPs. Although there are currently no OA-selective drugs, it is likely that such a drug would have to reduce MMP gene expression to have clinical efficacy.

Correlation of serum MMP3 and other biomarkers with clinical outcomes in patients with ankylosing spondylitis: a pilot study

The studies aimed to assess a set of biomarkers for their correlations with disease activity/severity of patients with ankylosing spondylitis (AS). A total of 24 AS patients were treated with etanercept and prospectively followed for 12 weeks. Serum levels of TNF-α, IFN-γ, TGF-β, IL6, IL15, IL17, MMP3, and MICA were measured at baseline and after treatment. The change of these biomarkers was analyzed for correlations with MRI indices for joint inflammation, Bath Ankylosing Spondylitis Disease Activity Index, Bath Ankylosing Spondylitis Functional Index, AS Disease Activity Score, serum CRP, and ESR. The Wilcoxon rank sum test was used to compare the biomarker levels between pre- and post-treatment and between pre-treatment and controls. Both step-wise procedures based on the Akaike information criterion (AIC) and least absolute shrinkage and selection operator with fivefold cross-validation were used to select the best model for pairwise correlations between the above clinical measures and the serum biomarkers. Serum levels of both MMP3 and IL6 were significantly higher in AS patients at baseline. After treatment, the levels of MMP3 decreased, but TGF-β and TNF-α increased significantly. The changes of serum MMP3 and MICA were significantly associated with MRI sacroiliac joint (SIJ) scores. CRP was positively correlated with serum MMP3 and IL6. The pattern of combined changes of serum MICA, MMP3, TGF-β, IL17, TNF-α, and IFN-γ predicted the MRI score of SIJ by logistic regression analysis. Specific serum biomarkers were significantly associated with clinical measures of AS. Most prominently, serum MMP3 level was found to have a positive correlation with the MRI score of SIJ and CRP. Serum MICA level negatively correlated with disease remission.

Spondyloarthritis: Matrix Metalloproteinasesas Biomarkers of Pathogenesis and Response to Tumor Necrosis Factor (TNF) Inhibitors

The term spondyloarthritis (SpA) is used to describe a group of multifactorial chronic inflammatory diseases characterized by a predisposing genetic background and clinical manifestations typically involving the sacroiliac joint. The absence of pathognomonic clinical and/or laboratory findings generally results in a delay in diagnosis and, consequently, in treatment. In addition, 20–40% of SpA patients are non-responders to tumor necrosis factor (TNF) inhibitor therapies. Given these considerations, it is important to identify biomarkers that can facilitate the diagnosis and assessment of disease activity. As inflammation plays a key role in the pathogenesis of SpA, inflammatory mediators have been investigated as potential biomarkers for diagnosing the disease and predicting response to therapy. Some investigators have focused their attention on the role of matrix metalloproteinases (MMPs), which are known to be markers of synovial inflammation that is generated in the joint in reaction to inflammatory stimuli. Several studies have been carried out to verify if serum MMPs levels could be useful to diagnose SpA, to assess disease severity, and to predict response to TNF inhibitor therapy. The current review focuses on MMPs’ role in SpA pathogenesis, diagnosis and therapeutic implications.

Low prevalence of knee chondrocalcinosis and its catabolic association with serum matrix metalloproteinase 3: A rural Japanese population study

AIM

This study aimed to elucidate the prevalence of radiographic knee chondrocalcinosis (CC) and to clarify whether CC is correlated with self-reported knee symptoms and a serum catabolic biomarker.

METHODS

A total of 1278 volunteers participated. Plain radiographs of both knees were obtained. Identification of a linear calcification in the knee joint space was defined as CC. Patients with a Kellgren-Lawrence grade of 2 or more were considered to have knee osteoarthritis (OA). Symptoms were evaluated using the Knee injury and Osteoarthritis Outcome Score (KOOS) Pain scale, and serum matrix metalloproteinase-3 (MMP-3) concentration was determined. Multiple regression analysis was conducted to determine whether CC was correlated with OA, the KOOS Pain scale and MMP-3 concentration.

RESULTS

Twenty-eight subjects were found to have CC (2.2%), and 389 had OA (30.4%). CC was correlated with OA (odds ratio: 5.797; P = 0.006). Additionally, CC was correlated with MMP-3 concentration (B = 11.415, β = 0.059, P = 0.014), but not with KOOS Pain scale.

CONCLUSIONS

The prevalence of CC was low in the Japanese population evaluated in this study. While CC was not correlated with self-reported knee symptoms, it was positively correlated with serum MMP-3 concentration.

Serum inflammatory biomarkers fail to identify early axial spondyloarthritis: results from the SpondyloArthritis Caught Early (SPACE) cohort

Introduction

Decreasing the diagnostic delay in axial spondyloarthritis (axSpA) remains a major challenge. Here, we assessed the value of serum inflammatory biomarkers to distinguish early axSpA from other pathologies in a large cohort of patients referred with early back pain.

Methods

Serum c reactive protein (CRP), erythrocyte sedimentation rate (ESR) and calprotectin were determined in the SPondyloArthritis Caught Early (SPACE) cohort (n=310), an early back pain inception cohort. Additionally, explorative serum biomarkers derived from the literature (interleukin-27 (IL-27), human β-defensin-2 (hBD-2) and lipcolin-2 (LCN-2)) were determined by ELISA in full-blown patients with ankylosing spondylitis (AS) (n=21) and healthy controls (n=20).

Results

Serum CRP and ESR levels were not elevated in early axSpA versus ‘control’ back pain patients. Serum calprotectin was elevated in early axSpA versus controls (p=0.01) but failed to identify early axSpA at the individual level (positive predictive value of 38.7%). As to explorative biomarkers, serum levels of IL-27 were not detectable, and hBD-2 and LCN-2 serum levels were not elevated in full-blown AS versus healthy controls (p=0.572, p=0.562, respectively). Therefore, these markers were not further determined in the SPACE cohort.

Conclusions

None of the candidate serum inflammatory markers were useful as diagnostic markers in the early phase of axSpA.

Ultrasonographic evaluation of femoral cartilage thickness in patients with psoriatic arthritis

BACKGROUND

Psoriatic arthritis (PsA) is a common form of arthritis that may vary from asymmetric oligoarthritis to symmetric polyarthritis and spondyloarthritis.

OBJECTIVES

To evaluate femoral cartilage thickness using ultrasonography in patients with PsA.

METHODS

Thirty-three patients (24 female, 9 male) with a diagnosis of PsA and 31 age-, sex- and body mass index-similar healthy subjects were enrolled in this study. Demographic and clinical characteristics of the patients were recorded, including disease duration, morning stiffness and medications. The femoral cartilage thicknesses of both knees (while held in maximum flexion) were measured with a 7-12 MHz linear probe. Three mid-point measurements were taken from both knees (at the lateral condyle, intercondylar area and medial condyle).

RESULTS

Cartilage thicknesses were similar between PsA patients and healthy control subjects. However, there were significant correlations between cartilage thickness and the Maastricht Ankylosing Spondylitis Enthesitis Score, Bath AS functional index and Bath AS disease activity index scores.

CONCLUSION

Femoral cartilage thickness is similar between PsA patients and healthy controls. The femoral cartilage thickness in PsA patients is associated with disease activity, functional inadequacy, and enthesopathy scores.

18F-fluoride PET/CT for detection of axial involvement in ankylosing spondylitis: correlation with disease activity

OBJECTIVES

Aim of the current study was to evaluate the relationships between the findings of 18F-fluoride PET/CT (F-PET/CT) reflecting osteo-proliferative processes and the clinical indexes related to the disease activity. The clinical indexes are Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score (ASDAS).

METHODS

We studied 29 AS patients aged 26-69 years with a wide range of disease activity using F-PET/CT. The number of regions of high bone turnover or osteoarthritis features at the spine and at sacroiliac joints was counted.

RESULTS

The number of F-PET/CT positive sites was significantly higher in patients with severe functional impairment and higher disease activity and it was positively related to both BASDAI (r = 0.336; P = 0.036) and ASDAS (r = 0.408; P = 0.014) while the number of degenerative features (osteoarthritis) was related neither with functional impact nor with disease activity.

CONCLUSIONS

With a single examination, F-PET/CT accurately identifies the functional impairment and the clinical involvement of AS. The good correlation we found between the number of F-PET/CT positive sites and disease activity candidates this technique also for follow-up of AS.

Biomarkers in axial spondyloarthritis

PURPOSE OF REVIEW

To assess the literature for biomarker validation studies that address key unmet needs related to the evaluation and management of patients with axial spondyloarthritis (SpA). This review focused on biomarkers facilitating early diagnosis and reflecting disease activity, structural damage on radiography, and clinical response to major therapies.

RECENT FINDINGS

Early diagnosis may be facilitated by measurement of antibodies to the human leukocyte antigen class II-associated invariant chain peptide (anti-CD74) but sensitivity declines with increasing duration of disease. No disease activity biomarkers have demonstrated consistent superiority over standard C-reactive protein (CRP), and future validation should employ multivariate analysis aimed at demonstrating the added value of any associated biomarkers beyond available clinical parameters of disease activity and the use of magnetic resonance imaging inflammation as the primary endpoint. Several biomarkers reflecting inflammation (CRP and calprotectin), angiogenesis (vasoactive endothelial growth factor), and connective tissue turnover (C2 M, C3 M, and citrullinated metalloproteinase degraded fragment of vimentin ) have recently been shown to reflect radiographic progression in multivariate studies adjusted for baseline severity. Future studies should be prospective and demonstrate that predictive capacity adds to the information provided by known predictors such as CRP and baseline modified Stoke AS Spine Score. Calprotectin is a promising predictor of response to major therapies for axial SpA.

SUMMARY

Several promising biomarkers addressing major unmet clinical needs require further validation in prospective studies.

Syndesmophyte growth in ankylosing spondylitis

PURPOSE OF REVIEW

Syndesmophytes are characteristic components of the spine disorder of ankylosing spondylitis. Understanding their growth may reveal insights to pathogenesis and potential treatment. We review recent studies on rates of development of syndesmophytes, patient characteristics associated with more rapid syndesmophyte growth, local vertebral abnormalities that precede syndesmophytes, systemic biomarkers of syndesmophytes, and studies of medications.

RECENT FINDINGS

New syndesmophytes develop in one-third of patients over 2 years. Consistent clinical predictors are male sex, elevated serum C-reactive protein levels, and preexisting syndesmophytes. Concomitant vertebral inflammation and fat dysplasia on MRI predict future syndesmophytes at the same vertebral location, but most syndesmophytes do not have recognized antecedents. Associations with serum levels of Wingless pathway proteins are inconsistent, as are the results of observational studies of tumor necrosis factor-alpha inhibitors.

SUMMARY

Although there is better understanding of the frequency of syndesmophyte development, the pathogenesis of syndesmophytes remains unclear.

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.

Changes of serum levels of MMP-3, sRANKL, and OPG in juvenile-onset ankylosing spondylitis patients carrying different HLA-B27 subtypes

Ankylosing spondylitis (AS) patients whose symptom onset occurs before 16 years of age are termed juvenile-onset ankylosing spondylitis (JAS). Investigations suggested that JAS had worse functional outcome, and abnormality of bone metabolism can appear in early stage of AS. The objectives of this study are to compare changes of serum inflammatory and bone metabolic markers and to explore the relationship between these biomarkers and disease activity in JAS with different HLA-B27 subtypes. Serum matrix metallopeptidase-3 (MMP-3), soluble receptor activator of nuclear factor-κB ligand (sRANKL), and osteoprotegerin (OPG) were detected by ELISA in 56, 62, and 68 JAS patients, respectively, and 32 healthy individuals were as controls. Serum MMP-3 and sRANKL were significantly higher and OPG in JAS was slightly higher than those in controls. There was no significant difference in the level of MMP-3, sRANKL, and OPG among JAS patients with B27 negativity, B*2704, B*2705, and B*2715, respectively. Serum levels of MMP-3 showed positive correlation with BASDAI and BASFI (Bath Ankylosing Spondylitis Disease Activity Index and Functional Index). Serum level of sRANKL showed positive correlation with MMP-3 and negative correlation with disease duration. The significantly higher sRANKL expression suggested the enhanced osteoclast function and imbalance of RANKL/OPG system in the inflammatory process of JAS patients carrying different B27 subtypes. It should be paid attention to the abnormality of bone metabolism during the treatment of JAS.