BIOCOMPATIBILITY OF MEMBRANES USED IN THE TREATMENT OF RENAL-FAILURE

Haemodialysis membranes with a wide range of solute and hydraulic perm eabilities are used clinically. Such membranes are manufactured from e ither cellulose or synthetic co-polymers and their biocompatibility is commonly characterized by the complement activation and white cell ch anges observed during their use. The cellobiosic unit may be modified by the partial or total replacement of the hydroxyl groups by diethyla minoethyl (Hemophan(TM)), acetate (cellulose acetate), triacetate (cel lulose triacetate) or 2,5-acetate (Diaphan(TM)). We have undertaken a prospective study in which such renal membranes have been studied in t erms of the complement activation and neutropenia produced with the ai m of investigating the relationship between modification of the cellob iosic unit and the magnitude of neutropenia and complement activation, and the extent to which membrane base material influences these param eters, by comparing the changes observed in modified cellulose membran es with that for a synthetic membrane (polysulphone). Our findings sho w that, while the degree of substitution varies between <1% and total substitution, there is no correlation between the numbers of hydroxyl groups replaced and alteration of complement activation and neutropeni a. However, by modification of the cellobiosic unit it is possible to produce a membrane whose biocompatibility is similar to that of a memb rane manufactured from a synthetic co-polymer such as polysulphone.