Intrahepatic Vascular Anatomy in Rats and Mice—Variations and Surgical Implications

Abstract

IntroductionThe intra-hepatic vascular anatomy in rodents, its variations and corresponding supplying and draining territories in respect to the lobar structure of the liver have not been described. We performed a detailed anatomical imaging study in rats and mice to allow for further refinement of experimental surgical approaches.MethodsLEWIS-Rats and C57Bl/6N-Mice were subjected to ex-vivo imaging using μCT. The image data were used for semi-automated segmentation to extract the hepatic vascular tree as prerequisite for 3D visualization. The underlying vascular anatomy was reconstructed, analysed and used for determining hepatic vascular territories.ResultsThe four major liver lobes have their own lobar portal supply and hepatic drainage territories. In contrast, the paracaval liver is supplied by various small branches from right and caudate portal veins and drains directly into the vena cava. Variations in hepatic vascular anatomy were observed in terms of branching pattern and distance of branches to each other. The portal vein anatomy is more variable than the hepatic vein anatomy. Surgically relevant variations were primarily observed in portal venous supply.ConclusionsFor the first time the key variations of intrahepatic vascular anatomy in mice and rats and their surgical implications were described. We showed that lobar borders of the liver do not always match vascular territorial borders. These findings are of importance for the design of new surgical procedures and for understanding eventual complications following hepatic surgery.

Animal Models of Steatosis (NAFLD) and Steatohepatitis (NASH) Exhibit Hepatic Lobe-Specific Gelatinases Activity and Oxidative Stress

“…The lobe-specific heterogeneity could be ascribed to the differential blood supply: recently Sanger et al described the intrahepatic vascular anatomy in liver rats and mice; of note, the lobar borders of the liver do not always match vascular territorial borders [14]: the ML and the lateral lobe are supplied by the main stem of the portal vein while the right median portal vein (2nd order) supplies the right ML [14]. Furthermore, it might be that a partial mixing of blood from the gastrointestinal tract and spleen occurs leading to difference in delivery of different nutrients or toxins to the liver lobes.…”

“…Animal models used were approved by the Italian Ministry of Health and by the local University Animal Care Commission (Document number 2/2012). At the time of sacrifice, on the basis of rat lobar structure, recently described by Sanger et al [14], liver samples from the superior right lobe (RL), right median lobe (ML), and lateral left lobe (LL) were collected and snap frozen in liquid nitrogen (Figure 1); serum blood samples were also collected.…”

Quantification of Hepatic Vascular and Parenchymal Regeneration in Mice

“…Despite these promising advances for visualization and quantification of vascular regeneration, this technique was not well established for livers in small experimental animals. We previously adapted this technique to rodent livers [ 11 ]. It proved to be very helpful to identify anatomical variants.…”

Closed-Loop Lumped Parameter Modeling of Hemodynamics During Cirrhogenesis in Rats

“…The small paracaval liver lobe (2% of total liver tissue), also called the caudate process and typically nourished by two different portal vein branches, remained undetected. Its impact on the perfusion, however, appears to be very limited as it only becomes important in the case of extended liver resection (90% partial hepatectomy) [19]. A similar branching scheme was observed for the HV.…”