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 syndro me. Dialysis-related amyloidosis, caused by the accumulation of beta(2 )-microglobulin (beta(2)M), has highlighted the need for a renal repla cement therapy that allows the elimination of LMWP in addition to smal l solutes. Synthetic membrane materials employed under hemofiltration conditions proved to be most effective in lowering elevated beta(2)M p lasma levels. In addition to convection, protein adsorption to artific ial membrane materials is an important mechanism for beta(2)M removal. Using an in vitro setup, 12 commercially available hemofilters repres enting 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 su rface, and the fraction of adsorbed LMWP varied between 14-70% of tota l protein adsorption and was negatively correlated to total protein ad sorption. beta(2)M adsorption showed up to an 8-fold difference betwee n membranes, and was negatively correlated with total protein adsorpti on and positively correlated with the adsorption of LMWPs.