Effect of remote ischemic preconditioning on hepatic microcirculation and function in a rat model of hepatic ischemia reperfusion injury.

Background: Liver transplantation involves a period of ischemia and reperfusion to the graft which leads to primary non-function and dysfunction of the liver in 5-10% of cases. Remote ischemic preconditioning (RIPC) has been shown to reduce ischemia reperfusion injury (IRI) injury to the liver and increase hepatic blood flow. We hypothesized that RIPC may directly modulate hepatic microcirculation and have investigated this using intravital microscopy.

Methods: A rat model of liver IRI was used with 45 min of partial hepatic ischemia (70%) followed by 3 h of reperfusion. Four groups of animals (Sham, IRI, RIPC+IRI, RIPC+Sham) were studied (n= 6, each group). Intravital microscopy was used to measure red blood cell (RBC) velocity, sinusoidal perfusion, sinusoidal flow and sinusoidal diameter. Neutrophil adhesion was assessed by rhodamine labeling of neutrophils and cell death using propidium iodide.

Results: RIPC reduced the effects of IRI by significantly increasing red blood cell velocity, sinusoidal flow and sinusoidal perfusion along with decreased neutrophil adhesion and cell death.

Conclusions: Using intravital microscopy, this study demonstrates that RIPC modulates hepatic microcirculation to reduce the effects of IRI. HO-1 may have a key role in the modulation of hepatic microcirculation and endothelial function.