Reduction of hepatic ischemia/reperfusion injury by a soluble P-selectin glycoprotein ligand-1.
OBJECTIVE
The authors' goal was to determine the effects of specific binding and blockade of P- and E-selectins by a soluble P-selectin glycoprotein ligand-1 (PSGL-1) in rat models of hepatic in vivo warm ischemia and ex vivo cold ischemia. The authors also sought to determine the effect of selectin blockade on isograft survival in a syngeneic rat orthotopic liver transplant model.


BACKGROUND
Ischemia/reperfusion (I/R) injury is a major factor in poor graft function after liver transplantation, which may profoundly influence early graft function and late changes. It is hypothesized that I/R injury leads to the upregulation of P-selectin, which is then rapidly translocated to endothelial cell surfaces within 5 minutes of reperfusion of the liver, initiating steps leading to tethering of polymorphonuclear neutrophil leukocytes to the vascular intima. Local production by leukocytes of interleukin-1, tumor necrosis factor-alpha, or both induces P-selectin expression on the endothelium and continues the cascade of events, which increases cell adherence and infiltration of the organ.


METHODS
To examine directly the effects of selectins in a warm hepatic I/R injury model, 100 microg of PSGL-1 or saline was given through the portal vein at the time of total hepatic inflow occlusion. The effects of PSGL-1 in cold ischemia were assessed using an isolated perfused rat liver after 6 hours of 4 degrees C storage in University of Wisconsin (UW) solution, with or without the instillation of PSGL-1 before the storage. To evaluate the effect of selectin blockade on liver transplant survival, syngeneic orthotopic liver transplants were performed between inbred male Sprague-Dawley rats after 24 hours of cold ischemic storage in UW solution. A separate group of animals received two doses of 100 microg of PSGL-1 through the portal vein before storage and before reperfusion of the transplanted liver. Recipient survival was assessed at 7 days, and the Kaplan-Meier product limit estimate method was used for univariate calculations of time-dependent recipient survival events.


RESULTS
In an in vivo warm rat liver ischemia model, perfusion with PSGL-1 afforded considerable protection from I/R injury, as demonstrated by decreased transaminase release, reduced histologic hepatocyte damage, and suppressed neutrophil infiltration, versus controls (p < 0.05). When cold stored livers were reperfused, PSGL-1 reduced the degree of hepatocyte transaminase release, reduced neutrophil infiltration, and decreased histologic hepatocyte damage (p < 0.05 vs. UW-only controls). On reperfusion, livers treated with PSGL-1 demonstrated increased portal vein blood flow and bile production (p < 0.05 vs. UW-only controls). In addition, 90% of the rats receiving liver isografts stored in UW solution supplemented with PSGL-1 survived 7 days versus 50% of those whose transplanted syngeneic livers had been stored in UW alone (p < 0.05).


CONCLUSIONS
Selectins play an important role in I/R injury of the liver. Early modulation of the interaction between P-selectin and its ligand decreases hepatocyte injury, neutrophil adhesion, and subsequent migration in both warm and cold rat liver ischemia models. In addition, the use of PSGL-1 before ischemic storage and before transplantation prevents hepatic injury, as documented by a significant increase in liver isograft survival. These findings have important clinical ramifications: early inhibition of alloantigen-independent mechanisms during the I/R damage may influence both short- and long-term survival of liver allografts.
Dulkanchainun
T S
TS
University of California-Irvine Department of Surgery, Orange, USA.
Goss
J A
JA
Imagawa
D K
DK
Shaw
G D
GD
Anselmo
D M
DM
Kaldas
F
F
Wang
T
T
Zhao
D
D
Busuttil
A A
AA
Kato
H
H
Murray
N G
NG
Kupiec-Weglinski
J W
JW
Busuttil
R W
RW
D000818:Animals; D001219:Aspartate Aminotransferases / Q000378:metabolism; D002448:Cell Adhesion; D008024:Ligands; D008107:Liver Diseases / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*; D016031:Liver Transplantation; D008297:Male; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D009077:Mucins; D019007:P-Selectin / Q000096:biosynthesis / Q000187:drug effects*; D009195:Peroxidase / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*; D012995:Solubility; D015854:Up-Regulation
D008024:Ligands; D008562:Membrane Glycoproteins; D009077:Mucins; D019007:P-Selectin; C084882:P-selectin ligand protein; D009195:Peroxidase; D001219:Aspartate Aminotransferases