Peritoneal effluent MMP-2 and PAI-1 in encapsulating peritoneal sclerosis.

Background: Recently, the use of effluent matrix metalloproteinase 2 (MMP-2) and plasminogen activator inhibitor 1 (PAI-1) as potential biomarkers of peritoneal fibrosis has been demonstrated during longitudinal follow-up of incident peritoneal dialysis (PD) patients. This study focuses on effluent MMP-2 and PAI-1 as early diagnostic markers in the preceding years of patients who develop encapsulating peritoneal sclerosis (EPS).

Study Design: Diagnostic test study.

Settings & Participants: PD patients who developed EPS were compared with controls using a 1:3 case-control design with a minimum PD duration of 57 months.

Index Tests: Dialysate appearance rates of MMP-2 and PAI-1.

Reference Test: EPS cases identified by 2 experienced nephrologists and a radiologist based on predefined criteria.

Results: 11 patients developed EPS within our center. The time course of MMP-2 appearance rates, studied by means of a linear repeated-measures model 4 years prior to the diagnosis of EPS, showed no difference between long-term controls and patients with EPS. In contrast, higher PAI-1 appearance rates were found in patients with EPS compared with controls (P=0.01). At a lag time of 1 year prior to EPS diagnosis, time-specific receiver operating characteristic curve analyses indicated a discriminative ability for PAI-1 appearance rate of 0.77 (95% CI, 0.63-0.91). A discriminative capacity was absent for those of MMP-2.

Limitations: Low event rate of EPS prevented independent validation in this single-center study.

Conclusions: Elevated levels of PAI-1 appearance rates are present in patients who develop EPS, pointing to progressive peritoneal fibrosis and sclerosis. The PAI-1 appearance rate has fair discriminative capacity from 3 years prior to EPS diagnosis. Therefore, effluent PAI-1 may aid in monitoring peritoneal fibrosis and serve as a biomarker for EPS.