Intra- and post-dialytic platelet activation and PDGF-AB release: Cellulose diacetate vs polysulfone membranes

Background. During haemodialysis the blood-membrane contact causes a release of platelet granule content, which contains platelet-derived growth factor AB (PDGF-AB). In view of the potential role of this in altering biocompatibility during haemodialysis, we evaluated the intra- and post-dialytic changes in PDGF-AB serum levels during haemodialysis sessions performed with cellulose diacetate (CDA) and polysulfone (PS) membranes respectively. Methods. PDGF-AB, platelet factor 4 (PF4), beta thromboglobulin (βTG), and mean platelet volume (MPV) levels were determined in 30 patients, each of whom underwent six dialysis sessions: three with a CDA and three with a PS membrane. Blood samples were taken at times 0, 15, 30, 120, 180, and 240 min during dialysis and at 1, 4, and 20 h after the end of the session. Statistical analysis was performed using a one-way ANOVA and Student's t test. Results. PDGF-AB at 15 min was increased to +41±9% with CDA vs +20±5% with PS (P<0.001) from the T0 values, and at 120 min it was +19±8% with CDA vs -25±9% with PS (P<0.001) from T0 levels. At 240 min it was +95±14% with CDA vs +49±15% with PS (P<0.001) from the T0 values, returning to basal only 20 h after the end of the session. βTG at 15 min was +60±8% for CDA vs +24±7.5% for PS (P<0.001) from the T0 values. PF4 showed a similar trend to βTG. MPV at 30 min from the start of dialysis was 7.4±0.3 fl with CDA and 8±0.3 fl with PS (P<0.001), and at 240 min MPV was 7.9±0.3 fl with CDA and 8.4±0.3 fl with PS (P<0.001). Conclusions. Platelet activation and platelet release reactions are lower with PS than with CDA membranes. PDGF-AB, released during and after dialysis, represents a clear biocompatibility marker. Its slow return to basal values and its action on vascular cells make it a potential risk factor for atherosclerosis in uraemic patients.