Daria V. Cherkashina

Reversible mitochondrial uncoupling in the cold phase during liver preservation/reperfusion reduces oxidative injury in the rat model☆

Reversible uncoupling of the mitochondrial electron-transport chain may be one strategy to prevent intracellular oxidative stress during liver cold preservation/warm reperfusion (CP/WR) injury. 2,4-Dinitrophenol (DNP) is a potent water-soluble uncoupling agent for supplementation of the hepatic CP solution. The aim of this work was to investigate the possible influence of DNP in the CP solution on the isolated rat liver state during CP/WR. Livers were subjected to CP at 4 degrees C in sucrose-phosphate based solution (SPS) for 18 h, followed by WR for 60 min in vitro. The final concentration of DNP was 100 microM. DNP presence during the CP stage led to partial ATP level decrease accompanied by a significant diminution in liver TBARS and a prevention of antioxidant enzyme activity decrease (catalase, GSH-PO, GSH-Red) when compared with livers stored without DNP. After DNP wash-out during WR, an improvement in the mitochondrial functional state (higher respiratory control indices and ATP levels, and a decrease in V(4) respiration rates) were observed. This was concurrent with lower TBARS levels, higher antioxidant enzyme activities and significant increase of bile production. The results suggest that reversible uncoupling may be one way to influence oxidative stress associated with hepatic cold preservation.

Mitochondria-targeted plastoquinone derivative SkQ 1 decreases ischemia-reperfusion injury during liver hypothermic storage for transplantation

The ability of the mitochondria-targeted plastoquinone derivative 10-(6′-plastoquinonyl)decyl triphenylphosphonium (SkQ1) to decrease ischemia-reperfusion injury in isolated liver during hypothermic storage (HS) was studied. Rat liver was stored for 24 h at 4°C without or in the presence of 1 μM SkQ1 with following reperfusion for 60 min at 37°C. The presence in the storage medium of SkQ1 significantly decreased spontaneous production of reactive oxygen species and intensity of lipid peroxidation in the liver during HS and reperfusion. The GSH level after HS in solution with SkQ1 was reliably higher, but reperfusion leveled this effect. At all stages of experiment the presence of SkQ1 did not prevent the decrease of antioxidant enzyme activities such as catalase, GSH peroxidase, GSH reductase, and glucose-6-phosphate dehydrogenase. The addition of SkQ1 to the storage medium improved energetic function of the liver, as was revealed in increased respiratory control index of mitochondria and ATP level. SkQ1 exhibited positive effect on the liver secretory function and morphology after HS as revealed in enhanced bile flow rate during reperfusion and partial recovery of organ architectonics and state of liver sinusoids and hepatocytes. The data point to promising application of mitochondria-targeted antioxidants for correction of the ischemia-reperfusion injury of isolated liver during long-term cold storage before transplantation.

Bioregulators of stem and progenitor cells in preservation solution reduce cold ischemia‐reperfusion injury of isolated rat livers

The effects of bioregulators of stem and progenitor cells (BSPC) of fetal tissue cytosol on rat liver during 24h hypothermic storage (HS) and following normothermic reperfusion (NR) were investigated. It was shown that BSPC presence in the preservation medium stabilized pro-oxidant-antioxidant balance impaired in liver after HS and NR, prevented the uncoupling of mitochondrial oxidative phosphorylation and ATP level decline. These consequences led to significant improvement of hepatic morphological integrity and functional state. Powerful protective effect of BSPC on liver at sub-zero temperatures can serve as basis for new approaches to extend safe time for organ preservation and foster understanding of pathways of stem and progenitor cell paracrine action.