Liver regeneration after portal vein embolization using absorbable and permanent embolization materials in a rabbit model.

To compare the safety and hypertrophy response after portal vein embolization (PVE) using 2 absorbable and 3 permanent embolization materials. Portal vein embolization is used to increase future remnant liver volume preoperatively. Application of temporary, absorbable embolization materials could be advantageous in some situations, provided sufficient hypertrophy is achieved from the nonembolized lobe. Six groups of rabbits (n = 5) underwent PVE of 80% of the total liver volume using saline (sham), gelatin sponge, fibrin glue, polyvinyl alcohol particles with coils, n-butyl cyanoacrylate, or polidocanol. The rabbits were killed after 7 days. Portography, computed tomographic volumetry, Doppler ultrasonography, laboratory liver function and damage parameters (nonembolized) liver-to-body weight ratio, immunohistochemistry, and cytokine and growth factor tissue levels were assessed to examine the differences in the liver regeneration response. Polidocanol was discontinued because of toxic reactions in 3 rabbits. Gelatin sponge was the only material that was absorbed after 7 days and resulted in less hypertrophy of the nonembolized lobe than the other 3 materials. There were no significant differences in hypertrophy response between the other 3 embolization groups. Volumetric data obtained from computed tomography were supported by liver-to-body weight ratio and the amount of proliferating hepatocytes. The volume gain of the nonembolized lobe was proportional to the volume loss of the embolized liver lobes. The number of Kupffer cells in the embolized liver lobe was significantly higher in the fibrin glue, polyvinyl alcohol particles with coils, and n-butyl cyanoacrylate groups than in the sham and gelatin sponge groups. However, the levels of interleukin-6, tumor necrosis factor-α, hepatocyte growth factor, and transforming growth factor-β1 were significantly lower. Temporary occlusion using gelatin sponge for PVE resulted in significantly less hypertrophy response than the use of permanent embolization materials. Except for polidocanol, none of the embolization materials exhibited evident hepatotoxicity.