Evaluation of filter membranes by the permeability of low-molecular-weight proteins-a remarkable inferiority to natural glmerular basement membrane

Abstract

Performance of six filters was evaluated by measuring sieving coefficient (SC) and plasma concentration of low-molecular-weight proteins (LMWP); β₂-microglobulin (β₂-mg, MW 11, 800), lysozyme (MW 14, 000), myoglobin (MW 17, 500), retinol-binding protein (RBP, MW 21, 000) and α₁-microglobulin (MW 33, 000), Permeability of LMWP was much lower in filter membranes than that of glomerular basement membrane, For example, SC of lysozyme and myoglobin in most permeable filter, Hemofresh was only 0.32 and 0.17 while they are 0.80 and 0.75 in natural glomerulus. Plasma leveles of β₂-mg, lysozyme and myoglobin were reduced after one hemofiltration procedure by Hemofresh.
But elevated plasma levels of LMWP were not reduced even by the long-term maintenance in hemofiltrationo In conclusion, more permeable filter for LMWP is required to make hemofiltration as a device of artificial kidney more akin to natural kidney.