LAUSR

R obles-Campos and collaborators reported about the contribution of the deportalized lobe (DL) to liver regeneration of the Future Liver Remant (FLR) in Torniquet-ALPPS. It is already known that the fast regeneration of FLR in the ALPPS procedure is mainly due to the following stimulating pathways: 1) variation in the vascular flow (portal shear stress and arterial buffer response) and 2) release of cytokines and other inflammatory factors. It is still unclear if the DL contributes to the regeneration of the FLR: 1) by supplementing the metabolic function of the liver while the FLR is focused on regeneration, or 2) by additional secretion of stimulating factors which act on the FLR. In the first scenario the DL acts as a transitory auxiliary liver that assists the metabolic, synthetic, and detoxifying functions for the first and critical week after resection. This knowledge has been already applied also in the context of Auxiliary Partial Orthotopic Liver Transplantation and the newly introduced RAPID concept (Resection And Partial Liver Segment 2–3 Transplantation With Delayed Total Hepatectomy). Additionally, the authors suggest that the DL stimulates the regeneration of the FLR through production and excretion of growing factors already 60 minutes after the procedure. All the secreted factors can act on the other liver cells by means of 1) ‘‘endocrine’’ signaling, after passing into the systemic circulation and reentering in the FLR through the left hepatic artery and left portal vein or 2) paracrine signaling, acting locally on nearby hepatocytes. Although this is the first observation in the context of Tourniquet-ALPPS, similar findings have been already reported in both humans and 4–6