Response of Angiopoietin-like Proteins 3 and 4 to Hemodialysis

Abstract

Patients on chronic hemodialysis (cHD) have decreased activity of lipoprotein lipase (LPL). Angiopoietin-like proteins (ANGPTL) 3 and 4 have been shown to inactivate LPL. The aim of this study was to investigate the levels of the ANGPTLs in plasma of cHD-patients and to evaluate if cHD may alter these levels. Baseline data were collected from cHD patients (n = 23), and controls (n = 23) and samples were analyzed from 17 patients during low-flux or high-flux HD, and from ultrafiltrate (n = 5). The levels of ANGPTL3 and 4, LPL and triglycerides were studied in a cross-over design on cHD with local citrate compared to tinzaparin as anticoagulant. The level of ANGPTL3 was higher than ANGPTL4 in patients and controls (p<0.01); the ANGPTL3 was 2.0 and ANGPTL4 was 3.3-fold higher in cHD versus controls. The levels of ANGPTL4 increased during cHD. After 180 min of HD the values had decreased again. When the dialysis was performed with high-flux filter, the mean level of ANGPTL4 at 180 min was below the value observed before cHD (p = 0.003). There was immunoreaction for ANGPTL4 in UFs when using high-flux, but not with low-flux, filter. ANGPTL3 was not detectable in UF. On cHD with citrate, no LPL activity was released into the blood. ANGPTL3 and ANGPTL4 were increased in HD patients. Anticoagulation with tinzaparin during cHD causes release of ANGPTL4 from tissues into blood. cHD using high-flux filters, to some extent, removed ANGPTL4. With citrate the levels of ANGPTL4 decreased.