PDGF-AB release during and after haemodialysis procedure

Background. During haemodialysis blood-membrane contact causes the release of the content of platelet alpha-granules, which contain platelet-derived growth factor (PDGF). In view of its possible role in accelerated atherosclerotic processes, we evaluated the intra- and post-dialytic changes in PDGF-AB serum levels during haemodialysis sessions performed using a cellulosic membrane. Methods. Using the ELISA method, PDGF-AB, platelet factor-4 (PF4) and beta-thromboglobulin (beta-TG) levels were determined in peripheral blood, as well as in arterial and venous haemodialyser lines, in 10 patients each of whom underwent five consecutive dialysis sessions with a CU membrane. Blood samples were taken at 0, 15, 30, 60, 120, 180 and 240 min during dialysis and at 1, 4 and 20 h after the end of the session. In the same group of patients the levels of the same molecules were also determined after a heparin bolus injection of 4500 IU, blood samples were taken at 0, 15 and 30 min after injection of the bolus. Results. PDGF-AB serum levels increased, remained consistently high during the haemodialysis session tin particular +134 +/- 20% after 30 min, P < 0.001, and + 140 +/- 5% after 240 min, P < 0.001) and returned to basal values only after 20 h following the end of the session. PF4 and beta-TG showed a similar trend to PDGF. The heparin bolus injection caused only a small increase (+15 +/- 5% at 30 min) in PDGF-AB serum levels. Conclusions. PDGF-AB is released during dialysis mainly as consequence of the blood-membrane contact and it returns only slowly to basal values.