Removal of trypsin complexed alpha-2 macroglobulin by plasma fractionation

The aim of this study is to assess in vitro the efficacy of a plasma fractionator to remove trypsin complexed alpha 2MG (alpha-2 macroglobulin) from human plasma in a manner analogous to the reticuloendothelial system (RES). Eval filter type "4A" (Kuraray Co., Osaka, Japan) was chosen as a plasma fractionator. Two and one half liters of bovine trypsin spiked human plasma was perfused in vitro through the fractionator in a single pass mode (n = 5). The concentrations of complexed alpha 2MG, total alpha 2MG, albumin, and IgM were measured before and after fractionation, and the concentration of free alpha 2MG and the sieving coefficients of each solute were calculated. The concentration of the trypsin complexed alpha 2MG measured by ELISA was significantly decreased by fractionation with Eval "4A" from 103.7 +/- 16.7 to 13.8 +/- 8.2 mg/L (reduction of 86.7%). Mean sieving coefficients of each solute were 0.133 +/- 0.079 in complexed alpha 2MG, 0.203 +/- 0.065 in free alpha 2MG, 0.203 +/- 0.065 in total alpha 2MG, 0.770 +/- 0.130 in albumin, and 0.070 +/- 0.010 in IgM. Although in vivo study will be required in patients with acute pancreatitis, in vitro study shows the feasibility of membrane plasma fractionation in eliminating trypsin complexed alpha 2MG.