Effects of portal vein arterialization on regeneration and morphology in liver transplantation: investigations using the rat model.
BACKGROUND
Portal vein arterialization (PVA) has been proposed as a technical variant in liver transplantation in the case of non-recanalizable thrombosis. The present study investigates the effects of the arterialized portal vein on the function, morphology, and regenerative behavior of the liver.


METHODS
Different PVA techniques, including orthotopic liver transplantation, were used in a rat model. Portal blood flow was measured using a ultrasonic flowmeter. The regeneration capacity was determined on the basis of the increase of liver weight and the proliferating cell nuclear antigen index. The amount of hydroxyproline and the transcript levels of procollagen I were measured to determine the degree of fibrosis. The extracellular matrix was visualized with Picro-Sirius staining.


RESULTS
The measurements obtained with an ultrasonic probe revealed a significant increase in portal blood flow after PVA. The regeneration capacity in the groups after PVA with no flow reduction was comparable to that of the control. Liver transplantation and PVA with no flow reduction was followed by a significant increase (four- to sixfold) in the amount of hydroxyproline and the level of the mRNA for procollagen I. In the Picro-Sirius staining, periportal and perivascular fibrosis with incipient formation of septa was seen. After reduction of the portal blood flow, these effects were significantly less pronounced.


CONCLUSIONS
These operative techniques represent an excellent small animal model for studying the mechanism of liver regeneration and the genesis of fibrosis in liver and vessel tissue. The presenting findings indicate that the negative effects of "overarterialization" may be largely avoided by reducing portal blood flow. This implies that permanent PVA in clinical liver transplantation should be performed only in conjunction with a down-regulation of portal flow.
Müller
Volker
V
Department of Surgery, University of Erlangen-Nuremberg, Krankenhausstrasse 12, D-91054 Erlangen, Germany. volker.mueller@chir.imed.uni-erlangen.de
Brummer
Daniela
D
Kissler
Hermann
H
Yedibela
Süleyman
S
Bauer
Michael
M
Erhardt
Wolf
W
Henke
Julia
J
Amann
Kerstin
K
Tannapfel
Andrea
A
Hohenberger
Werner
W
Ott
Rudolf
R
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001166:Arteriovenous Shunt, Surgical; D001391:Azo Compounds; D004396:Coloring Agents; D022781:Hepatocytes / Q000378:metabolism; D006909:Hydroxyproline / Q000378:metabolism; D008026:Ligation; D008099:Liver / Q000378:metabolism / Q000473:pathology; D008115:Liver Regeneration; D016031:Liver Transplantation; D008297:Male; D009929:Organ Size; D011167:Portacaval Shunt, Surgical; D011169:Portal Vein / Q000503:physiopathology / Q000601:surgery*; D011184:Postoperative Period; D011347:Procollagen / Q000235:genetics; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D012039:Regional Blood Flow; D012077:Renal Artery / Q000601:surgery*; D016019:Survival Analysis
D001391:Azo Compounds; D004396:Coloring Agents; D011347:Procollagen; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; C009798:C.I. direct red 80; D000410:Alanine Transaminase; D006909:Hydroxyproline