Clusterin is upregulated in serum and muscle tissue in idiopathic inflammatory myopathies and associates with clinical disease activity and cytokine profile.

OBJECTIVES: The aim of this cross-sectional study was to explore the circulating and skeletal muscle expression of clusterin (CLU) in inflammatory myopathies (IIM) and its potential implication in pathogenetic mechanisms of the disease. METHODS: A total of 85 IIM patients and 86 healthy controls (HC) were recruited. In addition, 20 IIM patients and 21 HC underwent a muscle biopsy. Circulating CLU was measured by ELISA. Serum cytokine profile of patients and HC was assessed by Cytokine 27-plex Assay. Immunohistochemical localisation of CLU was assessed in 10 IIM and 4 control muscle tissue specimens. The expression of CLU and myositis related cytokines in muscle was determined by qPCR. RESULTS: Serum levels of CLU were significantly increased in IIM patients compared to controls (86.2 (71.6-99.0) vs. 59.6 (52.6-68.4) µg/mL, p<0.0001) and positively correlated with myositis disease activity assessment (MYOACT) (r=0.337, p=0.008), myositis intention-to-treat activity index (MITAX) (r=0.357, p=0.004) and global disease assessment evaluated by physician (r=0.309, p=0.015). Moreover, serum CLU correlated with cytokines and chemokines involved in IIM and their combined effect on disease activity was revealed by multivariate redundancy analysis. In muscle tissue, CLU mRNA was increased in IIM patients compared to controls (p=0.032) and CLU accumulated in the cytoplasm of regenerating myofibres. CONCLUSIONS: We suggest that the up-regulation of clusterin in circulation and skeletal muscle of IIM patients may be an inflammation and atrophy induced response of the organism intended to limit the environment, favouring further muscle damage.

Alterations in activin A-myostatin-follistatin system associate with disease activity in inflammatory myopathies.

OBJECTIVES: The aim of this study was to investigate the systemic and skeletal muscle levels of atrophy-associated myokines in patients with idiopathic inflammatory myopathies (IIM) and their association with clinical characteristics of myositis. METHODS: A total of 94 IIM patients and 162 healthy controls were recruited. Of those, 20 IIM patients and 28 healthy controls underwent a muscle biopsy. Circulating concentrations of myostatin, follistatin, activin A and TGF-ß1 were assessed by ELISA. The expression of myokines and associated genes involved in the myostatin signalling pathway in muscle tissue was determined by real-time PCR. RESULTS: We report decreased levels of circulating myostatin (median 1817 vs 2659 pg/ml; P = 0.003) and increased follistatin (1319 vs 1055 pg/ml; P = 0.028) in IIM compared with healthy controls. Activin A levels were also higher in IIM (414 vs 309 pg/ml; P = 0.0005) compared with controls. Myostatin was negatively correlated to muscle disease activity assessed by physician on visual analogue scale (MDA) (r = -0.289, P = 0.015) and positively to manual muscle testing of eight muscles (r = 0.366, P = 0.002). On the other hand, follistatin correlated positively with MDA (r = 0.235, P = 0.047). Gene expression analysis showed higher follistatin (P = 0.003) and myostatin inhibitor follistatin-like 3 protein (FSTL3) (P = 0.008) and lower expression of activin receptor type 1B (ALK4) (P = 0.034), signal transducer SMAD3 (P = 0.023) and atrophy marker atrogin-1 (P = 0.0009) in IIM muscle tissue compared with controls. CONCLUSION: This study shows lower myostatin and higher follistatin levels in circulation and attenuated expression of myostatin pathway signalling components in skeletal muscle of patients with myositis, a newly emerging pattern of the activin A-myostatin-follistatin system in muscle wasting diseases.

Pro-inflammatory S100A11 is elevated in inflammatory myopathies and reflects disease activity and extramuscular manifestations in myositis.

BACKGROUND: S100A11 (calgizzarin), a member of the S100 family, is associated with oncogenesis, inflammation and myocardial damage. Our aim was to analyse S100A11 in idiopathic inflammatory myopathies (IIMs) and its association with disease activity features and cancer development. METHODS: S100A11 in muscle was determined by immunohistochemistry in polymyositis (PM), dermatomyositis (DM), myasthenia gravis (MG) and in subjects without autoimmune inflammatory disease (HC). S100A11 in plasma was measured in 110 patients with IIMs (PM, DM, and cancer associated myositis (CAM) patients) and in 42 HC. Disease activity was assessed by myositis disease activity assessment (MYOACT), muscle enzymes and C-reactive protein (CRP) were measured by routine laboratory techniques; autoantibodies by immunoprecipitation or by immunoblot. RESULTS: We observed an accumulation of S100A11 in the cytoplasm of regenerating and necrotizing muscle fibres of PM and DM patients. S100A11 was increased in plasma of all myositis patients compared to HC (3.8 (1.5-16.8) vs 2.8 (1.7-11.2) ng/ml, p = 0.011) and in DM and CAM patients compared to HC (4.0 (2.2-14.9) and 4.5 (1.5-9.1) vs 2.8 (1.7-11.2) ng/ml, p < 0.001 and p = 0.022, respectively). In all myositis patients, S100A11 correlated with the levels of lactate dehydrogenase (r = 0.256, p = 0.011), aspartate aminotransferase (AST) (r = 0.312, p = 0.002), CRP (r = 0.254, p = 0.022) and MYOACT (r = 0.245, p = 0.022). S100A11 was associated with MYOACT (r = 0.377, p = 0.030) and pulmonary and cutaneous disease activity in DM patients (r = 0.408, p = 0.017 and r = 0.417, p = 0.01, respectively). S100A11 was related to the levels of AST (r = 0.412, p = 0.027) in PM and to the levels of creatine phosphokinase (r = 0.432, p = 0.028) in CAM patients. CONCLUSIONS: We show for a first time a potential implication of S100A11 in the local inflammatory and tissue remodelling processes in myositis and an association of circulating S100A11 with disease activity and extra muscular manifestations in DM.

Serum visfatin levels in patients with axial spondyloarthritis and their relationship to disease activity and spinal radiographic damage: a cross-sectional study.

The purpose of this cross-sectional study was to assess the visfatin levels in patients with axial spondyloarthritis (axSpA) and to investigate the association between visfatin, disease activity and radiographic spinal damage. Serum visfatin levels were determined by enzyme-linked immunosorbent assay in 64 patients with axSpA (46 with radiographic axSpA (r-axSpA) and 18 with non-radiographic axSpA (nr-axSpA)) and 61 age-/sex-matched healthy individuals. Patients with r-axSpA were further divided into two subsets based on radiographic spinal damage using modified Stoke Ankylosing Spondylitis Spine Score (mSASSS = 0 and mSASSS ≥ 1). The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) was used to assess disease activity. C-reactive protein (CRP) levels and human leukocyte antigen (HLA)-B27 were determined. Visfatin levels were significantly higher in patients with axSpA and in the subgroup of patients with r-axSpA than in healthy individuals (p = 0.010 and p = 0.005, respectively), with no difference between patients with r-axSpA and with nr-axSpA. In general, disease activity was high (mean BASDAI 5.01) and was moderately correlated with visfatin levels (r = 0.585; p = 0.011) in patients with nr-axSpA. Visfatin levels correlated with mSASSS (r = 0.281; p = 0.026) and were significantly higher in axSpA patients with mSASSS ≥ 1 than in those with mSASSS = 0 (p = 0.025). Our study showed that circulating visfatin levels are elevated in axSpA patients, may be associated with disease activity in early phase of the disease and with the degree of radiographic spinal involvement.

Lower serum clusterin levels in patients with erosive hand osteoarthritis are associated with more pain.

BACKGROUND: The aims of this study were to analyse the serum concentrations of clusterin (CLU) in patients with hand osteoarthritis (OA) and in healthy controls, to compare CLU levels between patients with erosive and non-erosive disease, and to examine the association of CLU levels with clinical and laboratory parameters. METHODS: A total of 135 patients with hand OA (81 with erosive and 54 with non-erosive disease) and 53 healthy individuals were included in this study. All patients underwent clinical and hand joint ultrasound examination. The Australian/Canadian (AUSCAN) hand osteoarthritis index, algofunctional index and a visual analogue scale (VAS) for the measurement of pain were assessed. Serum levels of CLU were measured by an enzyme-linked immunosorbent assay (ELISA). RESULTS: Serum levels of CLU were significantly lower in patients with hand OA than in control subjects (p < 0.0001). In addition, patients with erosive hand OA had significantly lower CLU levels than those with non-erosive disease (p = 0.044). Negative correlations between CLU levels and pain as assessed by the AUSCAN score and the VAS were found in patients with erosive hand OA (r = - 0.275; p = 0.013 and r = - 0.220; p = 0.049, respectively). CONCLUSION: The present study demonstrates that lower concentrations of CLU are found in hand OA patients than in healthy individuals, especially in those with erosive disease, and that CLU concentrations have a negative association with hand pain.

Clusterin serum levels are elevated in patients with early rheumatoid arthritis and predict disease activity and treatment response.

Clusterin (CLU) is a molecular chaperone that participates in a variety of biological processes. Recent studies indicate its possible involvement in the development of bone erosions and autoimmunity. The aim of this study was to investigate its serum concentrations in patients with early rheumatoid arthritis (RA) and to explore their potential relationship with disease activity and treatment response. Serum levels of CLU were measured in 52 patients before and 3 months after the initiation of treatment and in 52 healthy individuals. CLU levels at baseline were significantly increased in patients with early RA compared with healthy subjects (p < 0.0001). After 3 months of treatment, the levels of CLU decreased and reached concentrations comparable to those in controls. Even though there was no relationship between CLU levels and disease activity at baseline, CLU levels positively correlated with disease activity at months 3, 6 and 12 after treatment initiation. Using ROC analysis, lower CLU baseline levels predicted achieving the therapeutic target of low disease activity and remission at months 3, 6 and 12. In summary, we found increased serum concentrations of clusterin in treatment-naïve patients with early rheumatoid arthritis, and we suggest clusterin as a predictive biomarker of disease activity and treatment response.

Chemokine and Cytokine Profiles in Patients with Hand Osteoarthritis.

BACKGROUND: The development of hand osteoarthritis (HOA) and its progression into the erosive subset are unclear, but inflammation is suspected to be the main source. To verify the involvement of inflammation in HOA pathogenesis, we evaluate serum inflammatory mediators and their association with HOA-related clinical features in patients. METHODS: 153 participants (50 non-erosive HOA patients, 54 erosive HOA patients, and 49 healthy control subjects) were included in this study. All patients underwent clinical examination, which included assessment of tender and swollen small hand joints, ultrasound (US) examination, and self-reported measures (e.g., AUSCAN or algofunctional indexes). Serum inflammatory mediators were quantified using human cytokine 27-plex immunoassay. We employed linear modelling, correlation analysis, and resampling statistics to evaluate the association of these mediators to HOA. RESULTS: We identified increased levels of nine inflammatory mediators (e.g., eotaxin, monocyte chemoattractant protein 1, interleukin-8, and tumour necrosis factor) in HOA patients compared to healthy controls. Increased mediators correlated with ultrasound findings as well as with clinically tender and swollen joint counts in patients with erosive HOA. However, none of the mediators distinguished between erosive and non-erosive HOA subtypes. CONCLUSION: Our findings support the hypothesis on the involvement of inflammation in HOA.

S100A4 is elevated in axial spondyloarthritis: a potential link to disease severity.

BACKGROUND: S100A4 is a member of calcium binding S100 protein family well known for its role in cancer progression and metastasis. Nevertheless, S100A4 also serves as a negative regulator of bone formation. Dickkopf-1 (DKK-1), marker of bone remodelling, is also implicated in the process of syndesmophyte formation in ankylosing spondylitis. The aim of our study was to evaluate plasma levels of S100A4 in patients with axial spondyloarthritis and to determine the potential association of S100A4 with disease severity, clinical manifestations and with bone changes in a cross-sectional study. METHODS: Fifty-eight patients with axial spondyloarthritis and 40 healthy controls were studied. Biological samples were analysed for S100A4 and Dickkopf-1. Disease activity was assessed according to the Bath Ankylosing Spondylitis Disease Activity Index. C-reactive protein (CRP) was used as a marker of inflammation. Radiographic damage was assessed using the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). RESULTS: The plasma levels of S100A4 were significantly higher in patients with axial spondyloarthritis compared to heathy controls (p < 0.0001). The levels of S100A4 were higher in early stages of the disease and lower in patients with the presence of syndesmophytes (p = 0.009). Furthermore, we found weak but significant inverse correlation of plasma S100A4 with the mSASSS (r = - 0.363, p = 0.030). Levels of S100A4 were negatively associated with disease duration (r = - 0.404, p = 0.002) and positively with Dickkopf-1 binding capacity (r = 0.312, p = 0.023). CONCLUSIONS: This is the first study showing elevated circulating levels of S100A4 in patients with axial spondyloarthritis, particularly in early stages of the disease prior to spinal involvement, and its significantly lower levels in patients with syndesmophytes. The role of S100A4 in the pathogenesis of axial spondyloarthritis can be suggested.