Adsorption of α1- and β2-microglobulin by PMMA filters in hemodialysis patients in a randomized crossover open-label comparative study

The prognosis of patients undergoing hemodialysis remains poorer than that of the general population, partly because of the insufficient removal of medium- and high-molecular-weight solutes using conventional filters. Polymethylmethacrylate (PMMA) filters may enhance solute removal via adsorption; however, their detailed properties remain unclear. This study investigated the adsorption and removal of β 2 -microglobulin (β2-MG) and α 1 -microglobulin (α1-MG) using PMMA filters in patients with end-stage kidney disease (ESKD). A randomized crossover study compared PMMA and polysulfone (PS) filters in 10 patients with ESKD. Blood-side clearance, adsorption clearance, and total adsorption of β2-MG and α1-MG were measured during hemodialysis. The adsorption of β2-MG by PMMA was greater than by PS (170.1 ± 84.7 mg vs. − 20.5 ± 34.7 mg, 15–240 min, p = 0.0001 ). The adsorption was higher with PMMA than with PS (248.3 ± 152.5 vs. − 17.7 ± 251.4 mg, p = 0.0033 ), and total α1-MG removal was also greater with PMMA than with PS (290.6 ± 153.4 vs. 31.9 ± 253.8 mg, p = 0.0032 ). Blood-side clearance of α1-MG did not differ significantly between the filters (15.5 ± 16.6 vs. 6.0 ± 12.1 mL/min at 60 min, p = 0.0909 ). PMMA filters showed superior adsorption of β2-MG and α1-MG compared with PS filters, suggesting an effective strategy for removing medium- and high-molecular-weight solutes through adsorption.