MyomiRs in cultured muscle cells from patients with idiopathic inflammatory myopathy are modulated by disease but not by 6-month exercise training.

OBJECTIVES: Idiopathic inflammatory myopathies/IIM are associated with changes in muscle-specific microRNA/miR. Exercise improves muscle function and metabolism in parallel with changes in miR expression. We investigated the effects of disease and exercise on miRs in differentiated muscle cells/myotubes from IIM patients and controls. METHODS: Samples of m. vastus lateralis were obtained by needle biopsy from IIM patients before/after 6-month training and from matched sedentary healthy controls. Muscle cell cultures were established and exposed to saturated fatty acid during differentiation. MiR-133a,-133b,-206,-1 and their target genes (qPCR), fat oxidation (FOx), lipids (chromatography) and mitochondrial oxidative phosphorylation (OxPHOS) complexes (immunoblotting) were measured. Interrelations between in vitro miRs and metabolism of myotubes as well as clinical parameters and disease activity/MITAX were explored. RESULTS: Levels of miRs were higher in myotubes derived from IIM patients compared to healthy controls (up to 3.5-fold, p<0.05). Neither 6-month training (IIM patients) nor in vitro palmitate treatment modulated myomiRs in myotubes. However, miR-133a,-133b, and miR-1 correlated negatively with FOx (p<0.01), triacylglycerols (p<0.05) and OxPHOS complex-V (p<0.05) and positively with OxPHOS complex-I (p<0.05) in myotubes. MiR-133a and miR-133b in myotubes were related to disease activity and fasting glycaemia in vivo (both p<0.05). CONCLUSIONS: Upregulation of microRNAs involved in myogenesis and regeneration in muscle cells derived from IIM patients indicates activation of compensatory epigenetic mechanisms, potentially aimed to counteract disease progression. Relationships of microRNAs with in vitro metabolic profile of muscle cells as well as with clinical parameters support the role of muscle-specific microRNAs in modulating muscle metabolism and clinical state of patients.

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.

[Cardiovascular risk in patients with rheumatic disease and its management]. / Kardiovaskulární riziko u pacientu s revmatickými chorobami a jeho management.

Cardiovascular disease (CVD) risk in patients with rheumatic diseases is increased by 50 % compared to the general population. This is a result of the increased inflammatory activity as well as modification of traditional CVD risk factors by the primary disease. So called lipid paradox, paradoxical decrease of concentrations of atherogenic plasma lipids due to increased inflammatory activity and their rise with successful anti-inflammatory treatment, is of particular importance. CVD risk in rheumatic diseases is further modified by drugs used for their treatment: while some treatment modalities increase the risk (e.g. glucocorticoids), others may act in an opposite direction (methotrexate, biological therapies). CVD risk stratification in patients with rheumatic diseases is uneasy; so far none of the specific scoring systems has been shown superior to traditional ones designed for the general population. Principles of cardiovascular risk intervention remain the same as for the general population: the management starts with lifestyle measures (healthy diet, increase in physical activity and smoking cessation) complemented with pharmacotherapy when indicated. Blood pressure as well as lipid lowering therapies should be led according to the same principles as in the general population and, also, to the same treatment goals. To improve CVD prevention outcomes in patients with rheumatic diseases it seems feasible to work in interdisciplinary teams led by a rheumatologist cooperating with a specialist in CVD prevention strategies (general practitioner, cardiologist, internist, diabetes specialist). A nutritional therapist and a physiotherapist are important members of the team, too. Interdisciplinary and complex CVD prevention in patients with rheumatic diseases decreases CVD morbidity.Key words: cardiovascular risk - intervention - lipid paradox - rheumatic diseases - risk factors - risk stratification.