Effect of cellulose acetate materials on the oxidative burst of human neutrophils

Following adverse clinical events involving seven patients undergoing renal dialysis using 12-year-old cellulose acetate hemodialyzers, this in vitro study was proposed in an effort to characterize the inflammatory response to the constituent cellulose acetate (CA) fiber materials. Chemiluminescence (CL) and apoptosis assays were used to determine whether human neutrophils were activated by CA fiber materials and/or are sensitive to degradation/alteration of these fibers over time. Furthermore, the study examined in vitro assays with human neutrophils using a CA film, the solvents used in the film preparation and CA resin. The film could be cut to identical sized pieces in an effort to compare hemodialysis material effects in standardized amounts. For the CL assays, 60-min exposure was followed by secondary stimulation with n-formyl-met-leu-phe (fMLP) or phorbol-12-myristate-13-acetate (PMA). Short-term exposure (60-min postintroduction to CA materials) increased the inflammatory response as measured by the respiratory burst of neutrophils (p < or =.05), with CA fiber exposure significantly compared with cells alone. There was a trend toward an increased response with exposure to older fibers with secondary PMA stimulation. Apoptosis was increased 12% with exposure to the more aged fibers versus 2% with the new fibers. The fiber storage component, glycerol, significantly inhibited the oxidative response (p < or =.001; > or =80% suppression with concentrations of 5-20%). The solvents used in film preparation, N,N-dimethylacetamide and tetrahydrofuran, produced greater than a 70% and 60% suppression, respectively, of CL activity for all concentrations > or =1%. More work is needed to determine the specific nature of the interaction of inflammatory cells with CA materials, but early evidence suggests that neutrophils are activated by CA and display an altered response to more aged fibers.