Validation of the prognostic value of MMP-7 in idiopathic pulmonary fibrosis

Respirology. 2017 Apr;22(3):486-493. doi: 10.1111/resp.12920. Epub 2016 Oct 19.

Abstract

Background and objective: Idiopathic pulmonary fibrosis (IPF) is a progressive disease with poor prognosis and variable clinical course. Although matrix metalloproteinase-7 (MMP-7) is emerging as an important IPF biomarker, reproducibility across studies is unclear. We aimed to determine whether a previously reported prognostic threshold for MMP-7 was predictive of mortality in an independent cohort of IPF patients.

Methods: MMP-7 concentrations obtained from heparinized plasma samples were determined by ELISA in 97 patients with IPF and 41 healthy controls. The association of the previously published heparin plasma MMP-7 threshold of 12.1 ng/mL with all-cause mortality or transplant-free survival (TFS) was determined, either as an independent biomarker or as part of the modified personal clinical and molecular mortality index (m-PCMI).

Results: MMP-7 plasma concentrations were significantly higher in IPF patients compared to healthy controls (14.40 ± 6.55 ng/mL vs 6.03 ± 2.51 ng/mL, P < 0.001). The plasma MMP-7 threshold of 12.1 ng/mL was significantly associated with both all-cause mortality and TFS (unadjusted Cox proportional hazard ratio (HR) = 25.85 and 15.49, 95% CI: 10.91-61.23 and 5.41-44.34, respectively, P < 0.001). MMP-7 concentrations, split by 12.1 ng/mL, were significantly (P < 0.05) predictive of mortality and TFS after adjusting for age, gender, smoking and baseline pulmonary function parameters, in a multivariate Cox proportional hazards model. MMP-7 concentrations were negatively correlated with diffusing lung capacity of carbon monoxide (DLCO ) (r = -0.21, P = 0.02), and positively with a mortality risk scoring system (GAP) that combines age, gender, forced vital capacity (FVC) and DLCO (r = 0.32, P = 0.001).

Conclusion: This study confirms that MMP-7 concentrations could be used to accurately predict outcomes across cohorts and centres, when similar collection protocols are applied.

Keywords: heparin plasma; idiopathic pulmonary fibrosis; matrix metalloproteinase-7; prognostic biomarker.

Publication types

  • Validation Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Biomarkers / blood
  • Case-Control Studies
  • Cohort Studies
  • Female
  • Humans
  • Idiopathic Pulmonary Fibrosis / blood*
  • Idiopathic Pulmonary Fibrosis / mortality*
  • Idiopathic Pulmonary Fibrosis / physiopathology
  • Idiopathic Pulmonary Fibrosis / surgery
  • Lung Transplantation
  • Male
  • Matrix Metalloproteinase 7 / blood*
  • Middle Aged
  • Prognosis
  • Proportional Hazards Models
  • Pulmonary Diffusing Capacity
  • Reproducibility of Results
  • Survival Rate

Substances

  • Biomarkers
  • Matrix Metalloproteinase 7