Serum autotaxin levels in chronic disease and acute exacerbation of fibrosing interstitial lung disease

BACKGROUND: Autotaxin (ATX) is an ecto-enzyme that catalyses the hydrolysis of lysophospholipids to the lipid mediator lysophosphatidic acid (LPA). LPA/ATX signalling has emerged as a new therapeutic target for pulmonary fibrosis; however, the serum levels and dynamics of ATX during the clinical course of fibrosing interstitial lung disease (ILD) remain unknown. This study sought to examine the serum ATX levels in fibrosing ILD in the chronic phase and in acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF). We aimed to elucidate the association between serum ATX level and clinical characteristics including disease progression and prognosis. METHODS: In total, 119 patients with fibrosing ILD and 38 healthy volunteers as controls were enrolled in the study and their serum ATX activity was analysed. We also included six male patients with AE-IPF in order to analyse the changes in serum ATX at the onset of AE-IPF. RESULTS: Patients with fibrosing ILD showed significantly higher serum ATX levels compared with healthy controls in both sexes. Per cent change in forced vital capacity after 1 year correlated with serum ATX levels in female patients. High serum ATX levels (>0.721 mg· L(−1)) were associated with worse outcome in survival curve and multivariate analysis of male patients. Serum ATX activity decreased after the onset of AE-IPF. CONCLUSION: Serum ATX levels were significantly higher in patients with fibrosing ILD compared with healthy controls, and this was associated with disease progression and outcome. This suggests the potential of serum ATX as a promising biomarker for the treatment of fibrosing ILD.