NMR-based serum and muscle metabolomics for diagnosis and activity assessment in idiopathic inflammatory myopathies

Abstract

Objectives: Differentiating smoldering disease activity from weakness due to fatty replacement of atrophied muscle can often be a challenge in the idiopathic inflammatory myositis (IIM). We aimed to identify the metabolic disturbances associated with IIM and if these changes can aid in the assessment of disease activity. Methods: Metabolic profiles of sera (N = 99) and muscle (N = 21) from patients with IIM (ACR-EULAR criteria) were compared with healthy control (HC) samples (N = 75 for serum and N = 12 for muscle tissues) employing 800 MHz NMR (Nuclear Magnetic Resonance) spectroscopy. Metabolic disparity between IIM and HC was established based on Partial Least Squares Discriminant Analysis (PLS-DA) and the discriminatory metabolites were identified based on variable importance in projection (VIP) statistics (P-value