Rat Model of the Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS) Procedure

Summary

Inducing rapid liver hypertrophy using Associating Liver Partition and Portal vein ligation for a Staged hepatectomy (ALPPS) has been proposed for resection of borderline resectable liver tumors. This model may elucidate mechanisms involved in rapid hypertrophy and allows testing of drugs that promote or block the acceleration of regeneration.

Abstract

Recent clinical data support an aggressive surgical approach to both primary and metastatic liver tumors. For some indications, like colorectal liver metastases, the amount of liver tissue left behind after liver resection has become the main limiting factor of resectability of large or multiple liver tumors. A minimal amount of functional tissue is required to avoid the severe complication of post-hepatectomy liver failure, which has high morbidity and mortality. Inducing liver growth of the prospective remnant prior to resection has become more established in liver surgery, either in the form of portal vein embolization by interventional radiologists or in the form of portal vein ligation several weeks prior to resection. Recently, it was shown that liver regeneration is more extensive and rapid, when the parenchymal transection is added to portal vein ligation in a first stage and then, after only one week of waiting, resection performed in a second stage (Associating Liver Partition and Portal vein ligation for Staged hepatectomy = ALPPS). ALPPS has rapidly become popular across the world, but has been criticized for its high perioperative mortality. The mechanism of accelerated and extensive growth induced by this procedure has not been well understood. Animal models have been developed to explore both the physiological and molecular mechanisms of accelerated liver regeneration in ALPPS. This protocol presents a rat model that allows mechanistic exploration of accelerated regeneration.

Introduction

The size of the liver remnant limits the resectability of liver tumors.¹ In general, when less than 25% liver tissue is left behind, the patient is at increased risk of death from acute liver failure due to the lack of metabolic function for the entire organism ("too small for size syndrome").² This post-hepatectomy liver failure is the most devastating complication after liver resection. Therefore clinicians have tried to induce liver regeneration prior to resection of the liver by manipulating the flow of the portal vein.³ It was found that, once the portal vein is occluded, the remainin....

Protocol

All experiments in this protocol were approved by the Veterinary Authorities of the Canton of Zürich, Switzerland (number 60/2014). Furthermore, all experimental steps were performed in strict compliance with the Guidelines on Experiments with Animals by the Swiss Academy of Medical Sciences (SAMS) and Guidelines of the Federation of European Laboratory Animal Science Associations (FELASA).

1. Animal Husbandry, Operating Room Equipment and Instruments, Anesthesia

1. Keep male Wistar rats with a weight of 250-300 g in ventilated cages under standard pathogen-free conditions in a 12/12 h light/dark cycle. Give animals free acces....

Results

The two different surgical procedures portal vein ligation (PVL) and PVL with transection (PVL+T) result in distinctly different growth kinetics. PVL induces moderate volume increase within 3 days, whereas in PVL+T a much larger right median lobe (RML) can be seen (Figure 5). This can be verified by daily volumetry. The volume of the RML roughly doubles within 3 days in PVL, while it triples in PVL+T.¹⁷

Discussion

This protocol presents an animal model of ALPPS with its rapid hypertrophy induced by PVL+T, that roughly doubles volume increase within 3 days compared to PVL alone.¹⁷ The right middle hepatic lobe is used as a model for the growing liver lobe because the middle hepatic lobe is one contiguous parenchymal mass supplied by two separate portal veins to its left and to its right side, as shown in Figure 1 in a recently published work.¹⁷ Compared t.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Isoflurane, 250 mL bottles	Attane, Piramal, Mumbai, India	LDNI 22098	Standard vet. equipment
Tec-3 Isofluorane Vaporizer	Ohmeda, GE-Healthcare, Chicago, IL	not available anymore	Standard vet. equipment
Buprenorphine (Temgesic)	Indivior, Baar, Switzerland	7680419310353	GTIN-number
Vitamine A ointment	Bausch&Lomp, Zug, Switzerland	7680223980247	GTIN-number
Atropine sulfate 0.5 mg/mL	Sintetica SA, Mendrisio, Switzerland	7680565330045	GTIN-number
Microsurgery microscope	Olympus, Tokio, Japan	SZX10	Standard vet. equipment
Betadine	Mundipharma, Basel, Switzerland	7680342821377	GTIN-number
Sponges	Carl Roth GmbH, Karlsruhe, Germany	NK83.1	Mini-sponges
Abdominal Wall retractors	N/A	N/A	Self-made from paper clips and Q-Tips
3-0 silk	Ethicon, Sommerville, NJ	K872H	Standard surgical
Scissors	World precision instruments (WPI), Sarasota, FL	503371	Standard microsurgical
Adson forceps	World precision instruments (WPI), Sarasota, FL	501244-G	Standard microsurgical
Fine tips microforceps	World precision instruments (WPI), Sarasota, FL	501976	Tips need to be polished regularly
Curved fine tips microforceps	World precision instruments (WPI), Sarasota, FL	504513	Essential to go around the portal vein branches
6-0 LOOK black braided silk	Surgical Specalities Corporation, Wyomissing, PA	SP114	Spool, precut prior to the procedure
2-0 silk sutures	Ethicon, Sommerville, NJ	K833	Standard surgical
5-0 maxon sutures	Covidien, Dublin, Ireland	6608-21	Standard surgical
Bipolar microforceps	Sutter, Freiburg, Germany	780148SGS	Essential for parenchymal transection
Q-tips small	Carl Roth GmbH, Karlsruhe, Germany	EH11.1	Standard surgical
Q-tips big	Carl Roth GmbH, Karlsruhe, Germany	XL54.1	Standard surgical
G30 needle	Terumo, Tokyo, Japan	NN-3013R	Standard anesthesia equipment
2 mm volume flow probe	Transonic Systems, Ithaca, NY	MA-2PS	Smallest available probe for HAT-311 flow meter
Transonic flow meter	Transonic Systems, Ithaca, NY	HAT-311 Transsonic flow QC meter	One of the  first generation flow flow meters for surgery
ExiTron nano 12,000	Miltenyi Biotech, Bergisch Gladbach, Germany	130-095-698	Nanomoloecular contrast medium that opacifies liver and spleen
G26 intravenous catheter	Becton Dickinson, Franklin Lakes, NJ	391349	Standard anesthesia equipment
Quantum FX MicroCT	Perkin Elmer, Waltham, MA	N/A	Standard small animal CT scanner at the institute of physiology, University of Zürich
OsiriX 8.0	Pixmeo Sarl, Geneva, Switzerland	N/A	Public domain software : www.pixmeo.com