Muscle-specific miRNAs in plasma and skeletal muscle of patients with idiopathic inflammatory myopathy are modulated by disease and training.

Objectives: Objective of this work was to examine myomiR levels in plasma, skeletal muscle, and skeletal muscle cells of patients with idiopathic inflammatory myopathy (IIM), their interrelations with the disease-related clinical phenotypes and with the effects of the disease-modifying 6-month training-intervention.

Methods: Samples of vastus lateralis muscle (n = 12/13) and plasma (n = 20/21) were obtained from IIM patients and healthy controls, respectively. Muscle and plasma were obtained before and after a 6-month training-intervention in 7 patients.

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.

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.

Altered dynamics of lipid metabolism in muscle cells from patients with idiopathic inflammatory myopathy is ameliorated by 6 months of training.

Key Points: Regular exercise improves muscle functional capacity and clinical state of patients with idiopathic inflammatory myopathy (IIM). In our study, we used an in vitro model of human primary muscle cell cultures, derived from IIM patients before and after a 6-month intensive supervised training intervention to assess the impact of disease and exercise on lipid metabolism dynamics. We provide evidence that muscle cells from IIM patients display altered dynamics of lipid metabolism and impaired adaptive response to saturated fatty acid load compared to healthy controls.

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.