STUDIES OF BIOCOMPATIBILITY OF DIFFERENT DIALYZER MEMBRANES - ROLE OFCOMPLEMENT-SYSTEM, INTRACELLULAR CALCIUM AND INOSITOL-TRIPHOSPHATE

PMNLs are activated during extracorporeal circulation. The aim of this cross-over biocompatibility study was to investigate the role of comp lement system, intracellular calcium [Ca2+](i) and inositol-triphospha te (IP3) on PMNL degranulation during hemodialysis (HD) with following membranes: polyamide, hemophane and cuprophane. In a second study the effect of complement system, intracellular calcium and IP3 on lactofe rrin release during HD with polysulfone and polymethylmethacrylate (PM MA) was also investigated. HD with cuprophane leads to the highest for mation of terminal complement component (TCC) followed by PMMA and hem ophane. There was a strong correlation between maximal arterial TCC fo rmation and procentual increase of plasma lactoferrin during hemodialy sis treatment with all membranes. Both HD with PMMA and hemophane lead s to a significant increase of resting [Ca2+](i) after 30 minutes of H D. Lowest TCC formation and lowest rise in [Ca2+](i) were observed wit h polysulfone and polyamide. Procentual and absolute increase of [Ca2](i) did also correlate with maximal TCC formation during HD using PMM A, hemophane, polyamide and polysulfone. Since cuprophane induces an i nitial drop of PMNLs, these cells could not be isolated during HD with cuprophane membranes. Resting PMNL IP3 values were similar before and 30 minutes after begin of hemodialysis and comparable with all membra nes used. These data indicate that TCC and intracellular calcium are i mportant signals for PMNL degranulation during HD with cuprophane, PMM A and hemophane. However, mild degranulation of specific PMNL granules can also occur in the absence of significant change in TCC, [Ca2+](i) or IP3 levels during HD with polyamide or polysulfone.