Removing Substances from Blood by Affinity Chromatography

Abstract

A B S T R A C T In vitro studies indicate that bilirubin and other albumin-bound substances can be efficiently removed from plasma by filtration over albumin-conjugated agarose beads. The effectiveness of this technique in vivo was investigated in rats by using a closed extracorporeal hemoperfusion system. Five Gunn rats whose endogenous bilirubin pool had been labeled with ['H]bilirubin and five Sprague Dawley rats with surgically created biliary obstruction were chosen as models of unconjugated and conjugated hyperbilirubinemia. Indocyanine green was injected into rats and its removal also studied. In the Gunn rats, 98% of the bilirubin was removed from plasma during the initial pass over the column as determined isotopically and chemically. Plasma bilirubin levels fell more than 70% from 8.2±1.6 mg/ 100 ml (mean±+SD) to 2.6±0.5 mg/100 ml during a 1-h hemoperfusion. An average of 1,061 yg of bilirubin was recovered from the columns, representing 22.5± 4.2% of the total exchangeable bilirubin pool and 96± 36.4% of the plasma pool. Results were similar in the rats with biliary obstruction and in those given indocyanine green. Normal Sprague Dawley rats experience minimal changes in formed blood elements, electrolytes, and proteins as the result of hemoperfusion. When the total volume of the column did not exceed 51% of the estimated blood volume of the animal, the survival rate was 100% in 20 studies, and the procedure was without observable ill effect. Extrapolation of both in vitro and in vivo data to man suggests that extracorporeal hemo-

Interactions of bilirubin and other ligands with ligandin

“…The results of the present study may predict competitive relationships in vivo for net hepatic uptake of various ligands. For example, bilirubin reduces hepatic uptake of sulfobromophthalein, Indocyanine Green, triiodothyronine, and penicillin (Scharschmidt et al, 1974;Lichter and Arias, 1975;Arias, 1972). Although Evans Blue (T-1824) is poorly transferred from plasma into the liver, it binds readily to ligandin in vitro (Levi et al, 1969).…”

Immobilized replicates of sequence 136–148 of human serum albumin as adsorbents for bilirubin

“…However, none of the existing adsorbents is entirely satisfactory for clinical use, their main shortcomings being nonspecificity and low capacity. Indeed, the most selective adsorbent thus far investigated, in terms of plasma components, has been immobilized H S A (6). However, the utility of this material is severely limited because of a low capacity, binding only two bilirubin molecules on a molecule of molecular weight in excess of 66 000.…”

Editorial: Haemoperfusion for jaundice.

“…Two recent papers,12 13 however, have described the removal of bilirubin by a completely different type of particle. Albumin was bound to agarose beads by a technique for coupling proteins to insoluble polysaccharides,14 and bilirubin was effectively removed from blood passed in vitro through a column of these beads without damaging either red cells or platelets.…”