Removal of digoxin and doxorubicin by multidrug resistance protein-overexpressed cell culture in hollow fiber.
BACKGROUND
Drug removal by hemoperfusion is not effective because of its lower capacity and nonspecificity. We invented a new hybrid type of hemodialysis system.


METHODS
An immortalized proximal tubular cell line (PCTL) overexpressing human multidrug resistance protein-1 (MDR-1) was cultured either on polus filter membranes or on hollow fiber modules. The modules were incubated in an incubator conditioned with 95% O2/5% CO2 that was kept at 37 degrees C. At 10 days on culture, the drug-transporting capacity of these systems was examined.


RESULTS
MDR was successfully expressed in the PCTL as evaluated by Western blot. Basolateral to apical transport of 3H-digoxin, a substrate of MDR, was examined by using the cells cultured on a microporous membrane. PCTL-MDR showed a 10-fold increase in MDR protein and a 12-fold increase of 3H-digoxin transport through a cell layer on a microporous membrane. The increase of the transport was abolished by the addition of 5 microM verapamil, an inhibitor of MDR, to the apical side. When digoxin or doxorubicin was infused in the capillary side of the hollow fiber modules after 10 days on culture, the largest portion of the drugs was transported to the pericapillary side (P < 0.001). This transport was also abolished by an addition of verapamil to the pericapillary side. Transport of para-aminohippurate was not different between two cells, and inulin was not transported in this system.


CONCLUSIONS
The hybrid hollow fiber system can selectively remove a significant amount of drugs that have an affinity to MDR from the medium, and perfuse them to the capillary side in vitro.
Department of Clinical Pharmacology and Pharmacology, Jichi Medical School, Tochigi, Japan.
S
S
Tsuruoka
K I
KI
Sugimoto
K
K
Ueda
M
M
Suzuki
M
M
Imai
A
A
Fujimura
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D002478:Cells, Cultured; D004077:Digoxin / Q000493:pharmacokinetics*; D004317:Doxorubicin / Q000493:pharmacokinetics*; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000378:metabolism; D011817:Rabbits; D006435:Renal Dialysis / Q000295:instrumentation* / Q000379:methods*
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D004077:Digoxin; D004317:Doxorubicin