Mouse erythrocytes as carriers for coencapsulated alcohol and aldehyde dehydrogenase obtained by electroporation - In vivo survival rate in circulation, organ distribution and ethanol degradation

Alcohol dehydrogenase and aldehyde dehydrogenase (ADH and ALDH) have been c oencapsulated into mouse erythrocytes by an electroporation technique. The optimal conditions were achieved as follows: 420 V, four pulses of 1 ms eve ry 15 min. at 37 degreesC, completed by resealing: 1 h at 37 degreesC. An e ncapsulation yield ranging from 11-12% was obtained for ADH + ALDH-loaded e rythrocytes. Carrier cell recovery was 52%. Electroporated-RBCs observed un der Scanning electron microscopy exhibited a tendency toward invaginated sp hero-stomatocytes. These invaginations were not found in electroporated/res ealed RBCs, The intravenous administration of Cr-51-RBCs manifested a bimod al pharmacokinetic profile: an initial phase (t(1/2 alpha)) with a rapid de crease of plasma Cr-51-RBCs followed by a slow and prolonged elimination ph ase (t(1/2 beta)), The values corresponding to in vivo survival rate during the elimination phase indicated that the survival rate of Cr-51-electropor ated loaded-RBCs was slightly lower (t(1/2 beta), 4.5 days) than Cr-51-nati ve RBCs (t(1/2 beta), 5.3 days). The mean clearance values from blood of el ectroporated Cr-51-RBCs (unloaded and loaded) were higher (0.51 %Cr-51/day and 0.54 %Cr-51/day, respectively) than the obtained for native Cr-51-RBCs (0.18 % Cr-51/day). The target organs for electroporated RBCs proved to be the same as for native RBCs. However, electroporated RBCs showed highest ac cumulation in liver, spleen and lung, since they were promptly recognized b y the reticuloendothelium system. Mice induced to the state of acute ethano l intoxication and treated with ADH + ALDH-RBCs clearly showed a lower leve l of ethanol concentration in plasma (less than 43% ethanol) than the intox icated mice treated with native RBCs. En consequence the clearance values o f ethanol from blood in intoxicated mice treated with ADH + ALDH-RBCs (0.39 ml/min) were higher than the treated with native RBCs (0.20 ml/min). The r esults obtained suggest that ADH + ALDH-loaded erythrocytes could be used a s a potential carrier system for in vivo removal of high levels of ethanol from blood caused by excessive alcohol consumption. (C) 2001 Elsevier Scien ce inc. All rights reserved.