In vitro plasma perfusion through adsorbents and plasma ultrafiltration to remove endotoxin and cytokines

In vitro plasma perfusion experiments were performed using small columns containing either resin or charcoal adsorbents to assess the removal of cytokines and endotoxin. 125I-labelled tumor necrosis factor-alpha (TNF-alpha; 500 pg/ml) and interleukin-6 (IL-6; 10 ng/ml) were added individually to human plasma. Over 4 hr of perfusion, Amberlite XAD-7 resin removed 32.5% +/- 3.3% (n = 5) of the initial amount of TNF-alpha and 71.4% +/- 3.8% (n = 5) of the initial amount of IL-6. DHP-1 polyhema-coated activated charcoal removed 17.2% +/- 6.2% (n = 5) of TNF-alpha and 48.5% +/- 7.4% (n = 5) of IL-6. Preliminary experiments were performed with lipopolysaccharide (LPS; 100 ng/ml) and interleukin-1 alpha (IL-1 alpha; 500 pg/ml), which showed that, over 4 hr, Amberlite XAD-7 removed 10.3% of the initial LPS and 29.1% of IL-1 alpha, whereas DHP-1 charcoal removed 23.2% of the initial LPS and 65.3% of IL-1 alpha. In vitro plasma ultrafiltration with either polysulfone or polyacrylonitrile membranes, as used clinically in haemodialysis, was performed with recirculation of plasma containing LPS or TNF-alpha. Neither of the substances was filtered to a significant degree. In conclusion, direct removal of these inflammatory mediators from the circulation of patients with multiorgan failure due to fulminant hepatic failure or sepsis would be possible by perfusion of plasma through adsorbents but not by haemodialysis.