Liver regeneration and recanalization time course following reversible portal vein embolization

Background/Aims Permanent portal vein embolization (PVE) is a widely practised technique. The use of an absorbable material would be safer in clinical situations in which the embolized liver is not resected. We evaluated the efficiency of reversible PVE in terms of liver regeneration and analyzed the precise time course of portal recanalization. Methods Nine monkeys underwent PVE of the left and right anterior portal branches using powdered absorbable material. Repeated portograms were carried out until complete revascularization of the embolized liver. Hepatocyte proliferation rates were assessed by BrdU incorporation. Liver segment volumes were determined by CT scans performed before embolization, then 1 month and 1 year after embolization. Results Reversible PVE induced significant hepatocyte proliferation in the non-embolized segments (13.5 ± 1.0%, 10.5 ± 0.8% and 9.1 ± 2.0% of cells on days 3, 5 and 7, respectively). One month after the embolization, the non-embolized liver volume had increased from 38.4 ± 1.3% to 54.8 ± 0.5% of total liver volume. Proximal and complete revascularization occurred 6–8 and 12–16 days, respectively. Conclusions Reversible PVE efficiently induces liver regeneration. The use of absorbable material avoids long-term liver scarring. Such material may be suitable for several clinical indications, including cell transplantation.