gms | German Medical Science

132. Kongress der Deutschen Gesellschaft für Chirurgie

Deutsche Gesellschaft für Chirurgie

28.04. - 01.05.2015, München

Visualization of liver regeneration after 70%PH in mice

Meeting Abstract

  • Chichi Xie - Universitätsklinikum Jena, Klinik für Allgemein-, Viszeral- und Gefäßchirurgie, Jena, Deutschland
  • W. Wei - Universitätsklinikum Jena, Jena, Deutschland
  • A. Schenk - Fraunhofer MEVIS, Bremen, Deutschland
  • O. Schwen - Fraunhofer MEVIS, Bremen, Deutschland
  • S. Zarafina - RWTH Aachen, Aachen, Deutschland
  • U. Dahmen - Universitätsklinikum Jena, Jena, Deutschland

Deutsche Gesellschaft für Chirurgie. 132. Kongress der Deutschen Gesellschaft für Chirurgie. München, 28.04.-01.05.2015. Düsseldorf: German Medical Science GMS Publishing House; 2015. Doc15dgch559

doi: 10.3205/15dgch559, urn:nbn:de:0183-15dgch5594

Published: April 24, 2015

© 2015 Xie et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.


Outline

Text

Introduction: Mouse partial hepatectomy (PH) model is the most common used model to investigate liver regeneration. However, little is known about the kinetics of vascular regeneration after liver resection in mice. The aim of this study was to

1.
establish a method to visualize vascular regeneration by injecting a contrast agent (Microfil) and subsequent CT-imaging of the explanted regenerating mouse liver,
2.
observe kinetics of vascular regeneration of portal and hepatic vein after 70% PH in mice.

Material and methods: Specimen preparation: Laparotomy was performed on anesthetized mice before, immediately after and on POD2 and POD7 after 70%PH (n=6/time point). Systemic heparinization was achieved by injecting heparinized saline via penile vein for 5min (300U/kg). Portal veinwas cannulated with 26G heparinized catheter and flushed with heparinized saline to remove the blood in liver and to prevent blood clotting using a speed-controlled perfusion device (0.4 ml/min). The mice were euthanized thereafter. Next, two specimen preparation methods were utilized: (1) portal vein vascular system (n=3/timepoint): Microfil reagent was perfused into portal vein after heparin perfusion via existing catheter (0.2 ml/min). (2) Hepatic vein vascular system: infrahepatic inferior vena cava (IVC) was cannulated with another 26G catheter. Microfil component was perfused into IVC to hepatic vein through this catheter after the branches of IVC were ligated and suprahepatic inferior vena cava was clamped.

Micro-CT scanning: The microfil samples scanned using a dual source micro-CT (Tomoscope Duo, CT-Imaging, Erlangen, Germany) as described by Josef Ehling, 2014. Scans were performed using the scan-protocol HQD-6565-360-90. Each flat panel detector acquired 720 projections (1032 x 1012 pixels) during one full rotation. X-ray sources wer operated at voltage 65 kV with current 0.5 mA. 3D-image analysis was performed via interactive segmentation using the Imalytics Preclinical Software (Gremse-IT, Aachen, Germany).

Results: Micro-CT images: Using the method described above, we could obtain micro-CT images suitable for 3D-reconstruction. Comparing the Micro-CT images obtained on POD2 with those obtained immediately after PH group, the vessel diameter doubled by POD 2. In contrast, the number of third order branches from both portal and hepatic venous tree did increase by POD2, but even more by POD 7, leading to an increased vascular density. Figure 1 [Fig. 1]

Conclusion: CT imaging of explanted livers after microfill contrasting the vascular tree represents a useful tool for visualizing vascular regeneration after partial hepatectomy. Vascular growth consists of enlarging the diameter of the vascular stem with its main branches and outgrowth of additional terminal branches in both the portal venous and hepatic venous tree.