Biomarkers in Psoriatic Arthritis: Recent Progress

Risk factors and early detection of joint damage in patients with psoriasis: a case-control study

BACKGROUND

Our aim was to target the unsatisfied need for early detection of the at-risk population and determine the subgroup of patients whose psoriasis (PsO) could transform into psoriatic arthritis (PsA).

METHODS

A retrospective and longitudinal case-control study was conducted at Beijing Chao-yang Hospital. It included 75 patients who were clinically diagnosed with PsA in the case group and 345 who solely suffered from PsO without PsA in the control group. A variety of baseline covariates were gathered from every patient with PsO. Univariate and multivariate analyses and receiver operating characteristic (ROC) curves were used to identify underlying risk factors and determine whether it was necessary to examine the imaging of PsO patients.

RESULTS

In multivariate logistic regression analysis, age ≥40 (odds ratio (OR): 1.04, 95% confidence interval (CI): 1.02-1.06, P < 0.01), nail involvement (OR: 1.17, 95% CI: 1.09-1.32, P < 0.01), erythrocyte sedimentation rate (ESR) (OR: 1.03, 95% CI: 1.01-1.06, P < 0.05) and elevated high-sensitivity C-reactive protein (hs-CRP) (OR: 1.31, 95% CI: 1.13-1.53, P < 0.01) were perceived to be risk factors for the transformation from PsO into clinical PsA. By combining magnetic resonance imaging (MRI)-detected enthesitis with tenosynovitis, combined predictors demonstrated better diagnostic efficacy, with an improvement in specificity (94.3% vs. 69%) and similarities in sensitivity (89% vs. 84.6%). The areas under the ROC curve (AUCs) amounted to 0.925 (95% CI: 0.882-0.967, P < 0.01) and 0.858 (95% CI: 0.814-0.903, P < 0.01).

CONCLUSIONS

It was identified that age ≥40, nail involvement, as well as an elevated ESR, and hs-CRP served as independent risk factors for PsO transforming into PsA. Additionally, MRI provides additional value for the early recognition of PsA.

Recent Advances in Biosensors for Diagnosis of Autoimmune Diseases

Over the last decade, autoimmune diseases (ADs) have undergone a significant increase because of genetic and/or environmental factors; therefore, their simple and fast diagnosis is of high importance. The conventional diagnostic techniques for ADs require tedious sample preparation, sophisticated instruments, a dedicated laboratory, and qualified personnel. For these reasons, biosensors could represent a useful alternative to these methods. Biosensors are considered to be promising tools that can be used in clinical analysis for an early diagnosis due to their high sensitivity, simplicity, low cost, possible miniaturization (POCT), and potential ability for real-time analysis. In this review, recently developed biosensors for the detection of autoimmune disease biomarkers are discussed. In the first part, we focus on the main AD biomarkers and the current methods of their detection. Then, we discuss the principles and different types of biosensors. Finally, we overview the characteristics of biosensors based on different bioreceptors reported in the literature.

Integrated RNA-Seq Analysis Uncovers the Potential Mechanism of the “Kidney Governing Bones” Theory of TCM

Background. As in philosophy of traditional Chinese medicine (TCM), the theory of “kidney governing bones” has been demonstrated by a series of scientific studies. Furthermore, many groups including ours have explored the molecular mechanisms related to bone development, growth, and regeneration using modern biology technologies, such as RNA sequencing (RNA-Seq) and isobaric tags for relative and absolute quantification (ITRAQ), and have demonstrated that the underlying molecular mechanisms were highly consistent with the “kidney governing bones” theory. Objective. Kidney-yang deficiency (YD), as a pathological condition, has a passive effect on the skeleton growth; more specifically, it is a state of skeletal metabolic disorder. However, the exact molecular mechanisms related to the “kidney governing bones” theory under the control of multiple organs and systems are still unknown. Methods. In this study, we performed RNA-Seq analysis to investigate and compare the gene expression patterns of six types of tissue (bone, cartilage, kidney, testicle, thyroid gland, and adrenal gland) from YD rats and normal rats and analyzed the interaction effects controlled by multiple functional genes and signaling pathways between those tissues. Results. Our results showed that, in the state of YD, the functions of bone and cartilage were inhibited. Furthermore, multiple organs involving the reproductive, endocrine, and urinary systems were also investigated, and our results showed that YD could cause dysfunctions of these systems by downregulating multiple functional genes and signaling pathways that positively regulate the homeostasis of these tissues. Conclusion. We ensure that “kidney governing bones” was not a simple change in a single gene but the changes in complex biological networks caused by functional changes in multiple genes. This also coincides with the holistic view of TCM, which holds that the human body itself is an organic whole and the functional activities of each organ coordinate with each other.

Assessment of Selected Matrix Metalloproteinases (MMPs) and Correlation with Cytokines in Psoriatic Patients

Metalloproteinases (MMPs) and cytokines have a great impact on the pathogenesis of psoriasis. Cytokines, as key mediators of inflammation and autoimmune processes, play a crucial role in the regulation of MMP expression in different cell types. Parallel, MMPs have an influence on cytokine production. This interaction was not well recognized in psoriatic patients. Our study is aimed at assessing the selected serum MMP levels and their correlations with cytokine levels in the serum of psoriatic patients. We observed a significantly elevated level of pro-MMP-1 and MMP-9 in psoriatic patients' serum in comparison to the control group. We did not observe any statistically significant differences of MMP-3 and pro-MMP-10 between the psoriatic patients and the control group. We did not observe any statistically significant differences in all the studied MMP levels between the patients with and without psoriatic arthritis (PsA). MMP-3 level correlated positively with proinflammatory cytokines, i.e., IL-12p/70, IL-17A, and TNF-α as well as MMP-3 and pro MMP-1 correlated positively with IL-4 in the psoriatic patients. In the control group, a positive correlation between pro-MMP-1 and TNF-α was found. These results confirm MMPs and Th1 and Th17 cytokine interaction in the inflammatory regulation in psoriasis.

The influence of tumour necrosis factor α inhibitors treatment - etanercept on serum concentration of biomarkers of inflammation and cartilage turnover in psoriatic arthritis patients

INTRODUCTION

Effective treatment in psoriatic arthritis (PsA) patients can protect them from severe musculoskeletal complications. For appropriate monitoring of anti-tumour necrosis factor α (anti-TNF-α) treatment in PsA, specific biomarkers are needed.

AIM

To investigate whether biological treatment with anti-TNF-α (etanercept 50 mg once a week subcutaneously) affects the activity of selected mediators of inflammation and destruction of articular cartilage: interleukin-6 (IL-6), interleukin-18 (IL-18), matrix metalloproteinases 1 and 3 (MMP-1, MMP-3), cartilage oligomeric matrix protein (COMP), human cartilage glycoprotein (YKL-40) in serum of patients with PsA.

MATERIAL AND METHODS

The study included 25 patients with PsA. The concentration of IL-6, IL-18, MMP-1, MMP-3, COMP and YKL-40 in serum was determined before, and 6 and 12 weeks after the beginning of anti-TNF-α treatment. Clinical severity of the disease according to the Body Surface Area, Psoriasis Area and Severity Index and Dermatology Life Quality Index as well as tender and swollen joint count (TJC, SJC) were also evaluated.

RESULTS

The study disclosed a statistically significant reduction in the serum concentration of IL-6, MMP-1 and YKL-40 in PsA patients after 6 and 12 weeks from the beginning of anti-TNF-α treatment (p = 0.00018 for IL-6; p = 0.01242 for MMP-1; p = 0.03263 for YKL-40).

CONCLUSIONS

IL-6, MMP-1 and YKL-40 may be useful for monitoring the effectiveness of anti-TNF-α treatment.

Psoriatic arthritis screening: a systematic review and meta-analysis

OBJECTIVE

To systematically review the accuracy and characteristics of different questionnaire-based PsA screening tools.

METHODS

A systematic review of MEDLINE, Excerpta Medical Database, Cochrane Central Register of Controlled Trials and Web of Science was conducted to identify studies that evaluated the accuracy of self-administered PsA screening tools for patients with psoriasis. A bivariate meta-analysis was used to pool screening tool-specific accuracy estimates (sensitivity and specificity). Heterogeneity of the diagnostic odds ratio was evaluated through meta-regression. All full-text records were assessed for risk of bias with the QUADAS 2 tool.

RESULTS

A total of 2280 references were identified and 130 records were assessed for full-text review, of which 42 were included for synthesis. Of these, 27 were included in quantitative syntheses. Of the records, 37% had an overall low risk of bias. Fourteen different screening tools and 104 separate accuracy estimates were identified. Pooled sensitivity and specificity estimates were calculated for the Psoriatic Arthritis Screening and Evaluation (cut-off = 44), Psoriatic Arthritis Screening and Evaluation (47), Toronto Psoriatic Arthritis Screening (8), Psoriasis Epidemiology Screening Tool (3) and Early Psoriatic Arthritis Screening Questionnaire (3). The Early Psoriatic Arthritis Screening Questionnaire reported the highest sensitivity and specificity (0.85 each). The I2 for the diagnostic odds ratios varied between 76 and 90.1%. Meta-regressions were conducted, in which the age, risk of bias for patient selection and the screening tool accounted for some of the observed heterogeneity.

CONCLUSIONS

Questionnaire-based tools have moderate accuracy to identify PsA among psoriasis patients. The Early Psoriatic Arthritis Screening Questionnaire appears to have slightly better accuracy compared with the Toronto Psoriatic Arthritis Screening, Psoriasis Epidemiology Screening Tool and Psoriatic Arthritis Screening and Evaluation. An economic evaluation could model the uncertainty and estimate the cost-effectiveness of PsA screening programs that use different tools.

Differentiating Psoriatic Arthritis From Psoriasis Without Psoriatic Arthritis Using Novel Serum Biomarkers

OBJECTIVE

There is a high prevalence of undiagnosed psoriatic arthritis (PsA) in patients with psoriasis. Identifying soluble biomarkers for PsA will help in screening psoriasis patients for appropriate rheumatology referral. We therefore aimed to investigate whether serum levels of novel markers previously discovered by quantitative mass spectrometric analysis of synovial fluid and skin biopsies performs better than the C-reactive protein (CRP) level in differentiating PsA patients from those with psoriasis without PsA (PsC).

METHODS

In this case-control study, serum samples were obtained from 100 subjects with PsA, 100 with PsC, and 100 healthy controls. Patients with PsA and PsC were group matched for age, sex, psoriasis duration, and Psoriasis Area and Severity Index and were not currently receiving biologic treatment. Using enzyme-linked immunosorbent assay, 4 high-priority markers (Mac-2-binding protein [M2BP], CD5-like protein [CD5L], myeloperoxidase [MPO], and integrin β5 [ITGβ5]), as well as previously established markers (matrix metalloproteinase 3 [MMP-3] and CRP level) were assayed. Data were analyzed using logistic regression. Receiver operating characteristic (ROC) curves were plotted.

RESULTS

In comparisons to controls, CD5L, ITGβ5, M2BP, MPO, MMP-3, and CRP level were independently associated with PsA, while only CD5L, M2BP, and MPO were independently associated with PsC alone. In comparisons to PsC, ITGβ5, M2BP, and CRP level were independently associated with PsA. ROC analysis of this model shows an area under the curve (AUC) of 0.85 (95% confidence interval [95% CI] 0.80-0.90). The model that included CRP level alone had an AUC of 0.71 (95% CI 0.64-0.78).

CONCLUSION

CD5L, ITGβ5, M2BP, MPO, MMP-3, and CRP level are markers for PsA. The combination of ITGβ5, M2BP, and CRP level differentiates PsA from PsC, and performs better than CRP level alone.

Recent advances in understanding and managing psoriatic arthritis

This article reviews recent advances in psoriatic arthritis (PsA) over the past several years with emphasis on early diagnosis, better understanding of pathogenesis, and new therapeutic approaches. Early diagnosis is important, since people who present late do not fare as well. There are a number of clinical, laboratory, and ultrasound features that can help identify patients destined to develop PsA, and several screening tools have been developed. It is recognized that genetic and epigenetic factors, as well as T cells and cytokines, play a role in the pathogenesis of PsA, and several targets have been identified for therapeutic interventions. New therapies have been developed and tested in PsA and have been found to be highly effective for both skin and joint manifestations of the disease. The expectation is that, in the future, PsA patients will be treated early and more aggressively and that there will not be significant progression of joint damage. Moreover, with effective treatment of the skin and joint disease and management of risk factors for the comorbidities, we can expect to reduce their occurrence and further reduce the excess mortality and reduced quality of life and function in these patients.

S100A8/A9, a potent serum and molecular imaging biomarker for synovial inflammation and joint destruction in seronegative experimental arthritis

Background

Seronegative joint diseases are characterized by a lack of well-defined biomarkers since autoantibodies are not elevated. Calprotectin (S100A8/A9) is a damage-associated molecular pattern (DAMP) which is released by activated phagocytes, and high levels are found in seronegative arthritides. In this study, we investigated the biomarker potential of systemic and local levels of these S100 proteins to assess joint inflammation and joint destruction in an experimental model for seronegative arthritis.

Methods

Serum levels of S100A8/A9 and various cytokines were monitored during disease development in interleukin-1 receptor antagonist (IL-1Ra)^–/– mice using ELISA and multiplex bead-based immunoassay, and were correlated to macroscopic and microscopic parameters for joint inflammation, bone erosion, and cartilage damage. Local expression of S100A8 and S100A9 and matrix metalloproteinase (MMP)-mediated cartilage damage in the ankle joints were investigated by immunohistochemistry. In addition, local S100A8 and activated MMPs were monitored in vivo by optical imaging using anti-S100A8-Cy7 and AF489-Cy5.5, a specific tracer for activated MMPs.

Results

Serum levels of S100A8/A9 were significantly increased in IL-1Ra^–/– mice and correlated with macroscopic joint swelling and histological inflammation, while serum levels of pro-inflammatory cytokines did not correlate with joint swelling. In addition, early serum S100A8/A9 levels were prognostic for disease outcome at a later stage. The increased serum S100A8/A9 levels were reflected by an increased expression of S100A8 and S100A9 within the ankle joint, as visualized by molecular imaging. Next to inflammatory processes, serum S100A8/A9 also correlated with histological parameters for bone erosion and cartilage damage. In addition, arthritic IL-1Ra^–/– mice with increased synovial S100A8 and S100A9 expression showed increased cartilage damage that coincided with MMP-mediated neoepitope expression and in vivo imaging of activated MMPs.

Conclusions

Expression of S100A8 and S100A9 in IL-1Ra^–/– mice strongly correlates with synovial inflammation, bone erosion, and cartilage damage, underlining the potential of S100A8/A9 as a systemic and local biomarker in seronegative arthritis not only for assessing inflammation but also for assessing severity of inflammatory joint destruction.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1121-z) contains supplementary material, which is available to authorized users.

The Assessment of Selected Bone and Cartilage Biomarkers in Psoriatic Patients from Poland

Background. Psoriasis is an inflammatory disease in which joints involvement may be insidious and difficult to detect. Bone and cartilage biomarkers may be helpful in screening patients with psoriasis for psoriatic arthritis (PsA). Objectives. To assess bone and cartilage serum biomarkers in psoriasis. Methods. The study was conducted in 2014 and included 61 psoriatic patients and 30 healthy individuals. In both groups, the serum concentrations of soluble receptor activator of nuclear factor-κB ligand (sRANKL), cartilage oligomeric matrix protein (COMP), osteoprotegerin (OPG), and interleukin-20 (IL-20) were examined. Severity of skin lesions was assessed by Psoriasis Area and Severity Index (PASI), body surface area (BSA), and Physician Global Assessment (PGA) scores. Results. The duration of psoriasis was from 1 year to 45 years. 22 patients suffered from concomitant PsA. The mean value of PASI was 23.1 ± 12.0 and BSA was 27.6 ± 20.6%. COMP, OPG, and IL-20 concentrations in psoriatic patients were significantly higher than in the control group. OPG/sRANKL ratio was significantly lower in PsA patients than in psoriatic patients without arthritis. Conclusions. Results of the conducted study suggest that COMP, OPG, IL-20, and OPG/sRANKL ratio may appear useful biomarkers of bone and cartilage involvement in psoriasis.

The translational revolution and use of biologics in patients with inflammatory skin diseases

Psoriasis and atopic dermatitis (AD) are common inflammatory skin diseases characterized by immune-mediated inflammation and abnormal keratinocyte differentiation. Although T-cell infiltration characterizes both diseases, T-cell polarization differs. Psoriasis is currently the best model for translational medicine because many targeted therapeutics have been developed and testing of targeted therapeutics has cemented psoriasis as IL-23/TH17 polarized. In patients with AD, although therapeutic development is approximately a decade behind that in patients with psoriasis, there is now active development and testing of targeted therapeutics against various immune axes (TH2, TH22, and IL-23/TH17). These clinical trials and subsequent molecular analyses using human samples will be able to clarify the relative roles of polar cytokines in patients with AD.