Ischaemia-reperfusion injury of the liver: treatment in theory and in practice

The Influence of Donor and Recipient Complement C3 Polymorphisms on Liver Transplant Outcome

Despite early reports of an impact of complement C3 polymorphism on liver transplant patient and graft survival, subsequent evidence has been conflicting. Our aim was to clarify the contributions of donor and recipient C3 genotype, separately and together, on patient and graft outcomes and acute rejection incidence in liver transplant recipients. Eight donor/recipient groups were analyzed according to their genotype and presence or absence of C3 F allele (FFFS, FFSS, FSFF, FSFS, FSSS, SSFF, SSFS, and SSSS) and correlated with clinical outcomes of patient survival, graft survival, and rejection. The further impact of brain death vs. circulatory death during liver donation was also considered. Over a median 5.3 y follow-up of 506 patients with clinical information and matching donor and recipient tissue, five-year patient and graft survival (95% confidence interval) were 90(81-91)% and 77(73-85)%, respectively, and 72(69-94)% were rejection-free. Early disadvantages to patient survival were associated with donor C3 F variant, especially in brain-death donors. Recipient C3 genotype was an independent determinant of graft survival by Cox proportional hazards analysis (hazard ratio 0.26, P = 0.04), and the C3 F donor variant was again associated with worse liver graft survival, particularly in brain-death donors. C3 genotype did not independently determine rejection incidence, but a greater proportion of recipient C3 F carriers were rejection-free in the circulatory death, but not the brain-death cohort. Cox proportional hazards analysis revealed significant effects of acute rejection on patient survival (hazard ratio 0.24, P = 0.018), of retransplantation on rejection risk (hazard ratio 6.3, P = 0.009), and of donor type (circulatory-death vs. brain-death) on rejection incidence (hazard ratio 4.9, P = 0.005). We conclude that both donor and recipient complement C3 genotype may influence patient and graft outcomes after liver transplantation but that the type of liver donor is additionally influential, possibly via the inflammatory environment of the transplant.

Post-reperfusion hydrogen gas treatment ameliorates ischemia reperfusion injury in rat livers from donors after cardiac death: a preliminary study

BACKGROUND AND PURPOSE

We reported previously that hydrogen gas (H₂) reduced hepatic ischemia and reperfusion injury (IRI) after prolonged cold storage (CS) of livers retrieved from heart-beating donors. The present study was designed to assess whether H₂ reduced hepatic IRI during donation of a cardiac death (DCD) graft with subsequent CS.

METHODS

Rat livers were harvested after 30-min cardiac arrest and stored for 4 h in University of Wisconsin solution. The graft was reperfused with oxygenated buffer, with or without H₂ (H₂ or NT groups, respectively), at 37° for 90 min on isolated perfused rat liver apparatus.

RESULTS

In the NT group, liver enzyme leakage, apoptosis, necrosis, energy depletion, redox status, impaired microcirculation, and bile production were indicative of severe IRI, whereas in the H₂ group these impairments were significantly suppressed. The phosphorylation of cytoplasmic MKK4 and JNK were enhanced in the NT group and suppressed in the H₂ group. NFkB-p65 and c-Fos in the nucleus were unexpectedly unchanged by IRI regardless of H₂ treatment, indicating the absence of inflammation in this model.

CONCLUSION

H₂ was observed to ameliorate IRI in the DCD liver by maintaining microcirculation, mitochondrial functions, and redox status, as well as suppressing the cytoplasmic MKK4-JNK-mediated cellular death pathway.

Quercetin dose affects the fate of hepatic ischemia and reperfusion injury in rats: An experimental research

BACKGROUND

Quercetin found in fruits and vegetables has an antioxidative effect. We aimed to investigate the protective effects of quercetin according to different doses on hepatic and ischemia-reperfusion (I/R) injury.

METHODS

Fifty mature male Sprague-Dawley rats were randomly divided into five groups (n = 10 for each). All the animal groups underwent laparotomy. Group 1 rats served as a sham-operated group. Groups 2-5 underwent 1 h hepatic ischemia and were followed by 2 h reperfusion. Group 3-5 animals received an additional intraperitoneal dose of 25, 50 or 100 mg/kg quercetin respectively before I/R operation. Blood samples were collected for determining serum aspartate transaminase (AST), alanine transaminase (ALT) and malondialdehyde (MDA) levels. Also, liver tissue samples were taken for measuring of liver MDA concentration and for histopathology assessment.

RESULTS

The highest levels of biochemical parameters were observed in group 2. In quercetin-treated groups, serum AST, ALT, MDA levels, and tissue MDA concentration were decreased as inversely with increasing quercetin dose. Microscopic evaluation revealed that most conspicuous histological improvement was observed in 50 mg/kg quercetin co-treated rats. 25 and 100 mg/kg quercetin co-treatment could not protect completely against hepatic I/R injury.

CONCLUSION

Quercetin can be effective in preventing of hepatic I/R injury when the correct dose was used.

No signs of inflammation during knee surgery with ischemia: a study involving inhaled nitric oxide

Nitric oxide donors and inhaled nitric oxide (iNO) may decrease ischemia/reperfusion injury as reported in animal and human models. We investigated whether the attenuation of reperfusion injury, seen by others, in patients undergoing knee arthroplasty could be reproduced when patients had spinal anesthesia. 45 consecutive patients were randomized into three groups (n = 15). Groups 1 and 3 were receiving iNO 80 ppm or placebo (nitrogen, N₂) throughout the entire operation, and group 2 only received iNO in the beginning and at the end of the operation. Blood samples were collected before surgery, at the end of the surgery, and 2 hours postoperatively. Muscle biopsies were taken from quadriceps femoris muscle before and after ischemia. There were no increases in plasma levels of soluble adhesion molecules: ICAM, VCAM, P-selectin, E-selectin, or of HMGB1, in any of the groups. There were low numbers of CD68+ macrophages and of endothelial cells expression of ICAM, VCAM, and P-selectin in the muscle analyzed by immunohistochemistry, prior to and after ischemia. No signs of endothelial cell activation or inflammatory response neither systemically nor locally could be detected. The absence of inflammatory response questions this model of ischemia/reperfusion, but may also be related to the choice of anesthetic method EudraCTnr.

Intrahepatic cholestasis after liver transplantation

Cholestasis is a common sequela of liver transplantation. Although the majority of cases remain subclinical, severe cholestasis may be associated with irreversible liver damage, requiring retransplantation. Therefore, it is essential that clinicians be able to identify and treat the syndromes associated with cholestasis. In this review, we consider causes of intrahepatic cholestasis. These may be categorized by time of occurrence, namely, within 6 months of liver transplantation (early) and thereafter (late), although there may be an overlap in their causes. The causes of intrahepatic cholestasis include ischemia/reperfusion injury, bacterial infection, acute cellular rejection, cytomegalovirus infection, small-for-size graft, drugs for hepatotoxicity, intrahepatic biliary strictures, chronic rejection, hepatic artery thrombosis, ABO blood group incompatibility, and recurrent disease. The mechanisms of cholestasis in each category and the clinical presentation, diagnosis, treatment, and outcome are discussed in detail.

Orthogonal polarization spectral imaging as a tool for the assessment of hepatic microcirculation: a validation study

BACKGROUND

Quantitative analysis of liver microcirculation using intravital fluorescence microscopy in animals has increased our knowledge about ischemia-reperfusion injury. However, because of the size of the instrumentation and the necessity of fluochromes for contrast enhancement, human liver microcirculation cannot be observed. Orthogonal Polarization Spectral (OPS) imaging is a recently introduced technique that can be used to visualize the microcirculation without the need for fluorescent dyes. It is a small, hand-held device and could potentially be used to study the microcirculation of the human liver in a clinical setting. However, before implementation into clinical use its ability to quantitatively measure microcirculatory parameters must be validated.

METHODS

The livers of Spraque-Dawley rats (n=9) were exteriorized, and images were obtained using OPS imaging and intravital fluorescence microscopy of the identical microvascular regions before and after the induction of a 20-min warm lobar ischemia. Images were videotaped for later computer-assisted off-line analysis.

RESULTS

OPS imaging can be used to accurately quantify the sinusoidal perfusion rate, vessel diameter, and venular red blood cell velocity. Correlation parameters were significant and Bland-Altman analyses showed good agreement for data obtained from the two methods at baseline as well as during reperfusion.

CONCLUSION

OPS imaging can be used to quantitatively measure microcirculatory parameters in the rat liver under both physiological and pathophysiological conditions. Thus, OPS imaging has the potential to be used to make quantitative measurements of the microcirculation in the human liver.

Interspecies differences in hepatic Ca(2+)-ATPase activity and the effect of cold preservation on porcine liver Ca(2+)-ATPase function

The accumulation of intracellular calcium ([Ca(2+)](i)) caused by ischemia-reperfusion during liver transplantation has been implicated as a factor leading to primary graft nonfunction. Plasma membrane (PM) and endoplasmic reticulum (ER) Ca(2+)-adenosinetriphosphatases (ATPases) are the primary transporters that maintain [Ca(2+)](i) homeostasis in the liver. We hypothesized that the porcine liver is better than the rat liver as a model for the study of human liver Ca(2+)-ATPase activity. We also hypothesized that cold preservation would depress Ca(2+)-ATPase activity in the porcine liver. Pig and rat livers were harvested, and human liver samples were obtained from surgical resection specimens. All were preserved with University of Wisconsin solution, and porcine livers were also preserved on ice for 2 to 18 hours. Ca(2+)-ATPase activity was measured after incubation with (45)Ca(2+) and adenosine triphosphate in the presence of specific Ca(2+)-ATPase inhibitors. Porcine PM and ER Ca(2+)-ATPase activities were 0.47 +/- 0.03 and 1.57 +/- 0.10 nmol of Ca(2+)/mg of protein/min, respectively. This was not significantly different from human liver, whereas rat liver was significantly greater at 2.60 +/- 0.03 and 9.2 +/- 0.9 nmol of Ca(2+)/mg of protein/min, respectively. We conclude that the Ca(2+)-ATPase activity in the pig liver is equivalent to that of human liver, and thus, the pig liver is a better model than the rat liver. Cold preservation studies showed a significant decrease in porcine hepatic PM Ca(2+)-ATPase activity after 4 hours of storage and near-total inhibition after 12 hours. Porcine hepatic ER Ca(2+)-ATPase activity showed a 45% decrease in activity by 12 hours and a 69% decrease by 18 hours. We conclude that cold ischemia at clinically relevant times depresses PM Ca(2+)-ATPase more than ER Ca(2+)-ATPase activity in pig liver homogenates.