PROTEIN ADSORPTION BY ARTIFICIAL MEMBRANE MATERIALS UNDER FILTRATION CONDITIONS

Elevated plasma levels of numerous low molecular weight proteins (LMWP) in renal insufficiency are likely to contribute to the uremic syndrome. Dialysis-related amyloidosis, caused by the accumulation of beta(2)-microglobulin (beta(2)M), has highlighted the need for a renal replacement therapy that allows the elimination of LMWP in addition to small solutes. Synthetic membrane materials employed under hemofiltration conditions proved to be most effective in lowering elevated beta(2)M plasma levels. In addition to convection, protein adsorption to artificial membrane materials is an important mechanism for beta(2)M removal. Using an in vitro setup, 12 commercially available hemofilters representing 11 different membrane materials were perfused with human blood containing I-125-labeled plasma proteins. Under filtration conditions, total protein adsorption ranged from 338-2,098 mg/m(2) of membrane surface, and the fraction of adsorbed LMWP varied between 14-70% of total protein adsorption and was negatively correlated to total protein adsorption. beta(2)M adsorption showed up to an 8-fold difference between membranes, and was negatively correlated with total protein adsorption and positively correlated with the adsorption of LMWPs.