Response of angiopoietin-like proteins 3 and 4 to hemodialysis.

ABSTRACT

BACKGROUND/AIM: 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. MATERIAL AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.