Serum Endothelin-1 Is Associated With Interstitial Lung Disease in Idiopathic Inflammatory Myopathy

Previous studies by our research group demonstrated that interstitial lung disease (ILD) associated with idiopathic inflammatory myopathy (IIM) correlates with endothelial cell injury and neutrophil extracellular trap (NETs) formation. This study aimed to investigate the clinical relevance of serum endothelin-1 (ET-1) and NET markers, such as cell-free DNA (cfDNA), in IIM-associated ILD (IIM-ILD).

Peripheral blood samples were collected from 60 patients with IIM (44 with dermatomyositis and 16 with polymyositis) and 20 healthy controls. Among the patients with IIM, 33 were diagnosed with ILD. Serum ET-1 and cfDNA levels were measured, and differences in ET-1 levels across groups, correlations between ET-1 and cfDNA, and diagnostic performance via logistic regression models and receiver operating characteristic (ROC) curves were analyzed.

Serum ET-1 levels were significantly elevated in patients with IIM compared to healthy controls (10.89 ± 3.49 pg/mL vs 2.09 ± 0.56 pg/mL, P < 0.0001). The subgroup with IIM-ILD exhibited a 36.3% increase in ET-1 levels compared to the subgroup with IIM without ILD (12.17 ± 3.67 pg/mL vs 9.34 ± 2.53 pg/mL, P = 0.0012), with a positive correlation between ET-1 and cfDNA (r = 0.374, P = 0.003). Multivariate analysis identified ET-1 as an independent risk factor for ILD (odds ratio 1.442, 95% confidence interval 1.082-1.923). A combined model incorporating ET-1, albumin-globulin ratio, lactate dehydrogenase, and complement C4 achieved an area under the ROC curve of 0.888 (sensitivity 78.8% and specificity 88.9%).

Serum ET-1 levels were elevated in patients with IIM, particularly in those with ILD, suggesting its potential role in the pathogenesis and progression of IIM-ILD.