Increased Vitronectin and Endothelin-1 in the Breath Condensate of Patients with Fibrosing Lung Disease

Background: Non-specific interstitial pneumonia (NSIP) and fibrosing alveolitis associated with systemic sclerosis (FASSc) are diseases of unknown aetiology that are characterised by the accumulation of mononuclear cells, followed by the progressive deposition of collagen within the interstitium and subsequent destruction of lung airspace. Better understanding of mediators involved in fibrosis may be useful for early diagnosis and in clinical monitoring of disease progression.

Objective: The aim of this study was to investigate the presence of two profibrotic markers, the vitronectin and the endothelin-1 (ET-1) in the airways of NSIP and FASSc patients.

Methods: Ten NSIP (6 males, age 57 +/- 2 years) and 15 FASSc (8 males, age 55 +/- 4 years) patients were recruited along with 10 normal subjects (4 male, age 52 +/- 2 years). Vitronectin and ET-1 concentrations were measured in their breath condensate, using a specific enzyme immunoassay.

Results: Higher levels of vitronectin and ET-1 were observed in NSIP and FASSc patients [median 92.8 (91.7-93.9) microg/ml; median 8.3 (7.9-9.3) pg/ml] than in control subjects [median 80.3 (89.3-91.4) microg/ml; p < 0.01; median 5.3 (4.9-5.9) pg/ml, p < 0.0001]. We also found increased concentrations of vitronectin in patients with clinical deterioration compared to those remaining stable and in ex-smokers compared to non-smokers and, increased vitronectin and ET-1 in patients treated with steroids compared to untreated patients.

Conclusion: These findings justify further studies of vitronectin and ET-1 levels in exhaled breath condensate, as a means of monitoring activity and predicting progression of pulmonary fibrosis.