Objective: We sought to investigate the biological effects of pre-reperfusion treatments of the liver after warm and cold ischemic injuries in a porcine donation after circulatory death model. Summary of Background Data: Donation after circulatory death represents a severe form of liver ischemia and reperfusion injury that has a profound impact on graft function after liver transplantation. Methods: Twenty donor pig livers underwent 60 minutes of in situ warm ischemia after circulatory arrest and 120 minutes of cold static preservation prior to simulated transplantation using an ex vivo perfusion machine. Four reperfusion treatments were compared: Control-Normothermic (N), Control- Subnormothermic (S), regulated hepatic reperfusion (RHR)-N, and RHR-S (n = 5 each). The biochemical, metabolic, and transcriptomic profiles, as well as mitochondrial function were analyzed. Results: Compared to the other groups, RHR-S treated group showed significantly lower post-reperfusion aspartate aminotransferase levels in the reperfusion effluent and histologic findings of hepatocyte viability and lesser degree of congestion and necrosis. RHR-S resulted in a significantly higher mitochondrial respiratory control index and calcium retention capacity. Transcriptomic profile analysis showed that treatment with RHR-S activated cell survival and viability, cellular homeostasis as well as other biological functions involved in tissue repair such as cytoskeleton or cytoplasm organization, cell migration, transcription, and microtubule dynamics. Furthermore, RHR-S inhibited organismal death, morbidity and mortality, necrosis, and apoptosis. Conclusion: Subnormothermic RHR mitigates IRI and preserves hepatic mitochondrial function after warm and cold hepatic ischemia. This organ resuscitative therapy may also trigger the activation of protective genes against IRI. Sub- normothermic RHR has potential applicability to clinical liver transplantation.
Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)
1
Background. Cholestasis is a sign of hepatic ischemia-reperfusion injury (IRI), which is caused by the dysfunction of hepatocyte membrane transporters (HMTs). As transcriptional regulation of HMTs during oxidative stress is mediated by nuclear factor erythroid 2-related factor 2, we hypothesized that bardoxolone methyl (BARD), a nuclear factor erythroid 2-related factor 2 activator, can mitigate cholestasis associated with hepatic IRI. Methods. BARD (2 mg/kg) or the vehicle was intravenously administered into rats immediately before sham surgery, 60 min of ischemia (IR60), or 90 min of ischemia (IR90); tissue and blood samples were collected after 24 h to determine the effect on key surrogate markers of bile metabolism and expression of HMT genes (Mrp (multidrug resistance-associated protein) 2, bile salt export pump, Mrp3, sodium-taurocholate cotransporter, and organic anion-transporting polypeptide 1). Results. Significantly decreased serum bile acids were detected upon BARD administration in the IR60 group but not in the IR90 group. Hepatic tissue analyses revealed that BARD administration increased mRNA levels of Mrp2 and Mrp3 in the IR60 group, and it decreased those of bile salt export pump in the IR90 group. Protein levels of multidrug resistance–associated protein 2, multidrug resistance–associated protein 3, and sodium-taurocholate cotransporter were higher in the IR90 group relative to those in the sham or IR60 groups, wherein the difference was notable only when BARD was administered. Immunohistochemical and morphometric analyses showed that the area of expression for multidrug resistance–associated protein 2 and for sodium-taurocholate cotransporter was larger in the viable tissues than in the necrotic area, and the area for multidrug resistance–associated protein 3 was smaller; these differences were notable upon BARD administration. Conclusions. BARD may have the potential to change HMT regulation to mitigate cholestasis in hepatic IRI.