Energy status in anoxic rat hepatocytes: Effects of isoflurane, solution composition, and hypothermia

Abstract

Both cold and warm ischemia occur during liver transplantation. Hypothermia and Wisconsin solution preserve adenine nucleotide energy status, which is crucial to hepatic function and viability. The volatile anesthetic isoflurane has been shown to preserve energy status in anoxic isolated hepatocytes in warm Krebs solution. The present study examined isoflurane effects on energy status during incubation also in Wisconsin or Krebs-plusadenosine solution at 37" or 4". Hepatocytes were isolated from rat liver after perfusion with Krebs + collagenase. In 25-mL flasks, 12.5 million cells in 2.5 mL of Krebs, Krebs plus 5 mmol/L adenosine, or Wisconsin solution were incubated under an atmosphere of 02/C02 or N2/CO2(19:1) & isoflurane (3 volumes% = 2ED50), for 30 minutes at 37°C or 4°C. Adenine nucleotides were measured uring liver transplantation, both cold and warm D anoxia and ischemia occur during procurement and implantation of the donor liver. Lack of oxygen inhibits adenosine triphosphate (ATP) formation by oxidative phosphorylation. Anaerobic glycolysis, even though maximally activated, is less efficient at forming ATP; consequently, there is a decline in cellular ATP levels and other measures of energy status such as energy charge (EC) and total adenine nucleotide level (TAN). The importance of these changes is indicated by evidence that the liver's ability to maintain or regain energy balance during and after surgical or anoxic insult predicts subsequent function and viability. have not been correspondingly well studied. Such information could be important to understanding the mechanism(s) by which UW preserves liver during ischemia and anoxia.6The volatile anesthetic isoflurane, at concentrations used clinically, has been shown to partially preserve energy status in isolated hepatocytes in Krebs buffer during warm anoxia.' During both short/reversible (30 minutes) and long/irreversible (90 minutes) anoxia, ATP, EC, and TAN values were significantly higher in the presence than in the absence of isoflurane (1.5 to 3 volumes per cent [vol%] ; 1-2 ED50; 1-2 MAC [mean alveolar concentration for surgical anesthesia]).* We studied how energy status was affected by exposure to isoflurane along with different incubation solutions and temperatures. Materials and MethodsApproval was obtained from the institutional animal care and use committee for preparation of hepatocytes from the livers of fed adult male Sprague Dawley rats weighing 275 g to 350 g. Animals were allowed free access to food and water before being anesthetized with pentobarbital 50 mg/kg intraperitoneally (IP). Recirculating perfusion of the liver was established in situ, with the portal vein cannulated for inflow and the inferior vena cava (using a transatrial approach) for outflow. Perfusion was camed out for 5 minutes at a flow rate of 35 to 40 mL/min using Ca2+-free Krebs-Henseleit buffer equilibrated with Or/C02(95/5 ~01%) at

Protection of the rat liver against rewarming ischemic injury by University of Wisconsin solution

“…On the other hand, our results are highly consistent with the study of Howard et al [24] and with the findings of Hannoun et al [8]. In the former study, it was shown that UW solution reduced cell damage in isolated rat hepatocyters during warm anoxia [24]. In the latter study, cooling of the liver with UW solution allowed Hannoun et al [8] to perform major hepatic resection in patients with diseased livers using hepatic vascular exclusion for longer than 1 h without increased morbidity or mortality.…”

“…While under hypoxic perfusion UW solution appeared to reduce liver injury, oxygenated reperfusion led to cell death in UW-treated livers, comparable with that found in control livers perfused with Krebs-Henseleit solution [23]. On the other hand, our results are highly consistent with the study of Howard et al [24] and with the findings of Hannoun et al [8]. In the former study, it was shown that UW solution reduced cell damage in isolated rat hepatocyters during warm anoxia [24].…”

The effects of N-acetylcysteine on hepatic function during isoflurane anaesthesia for laparoscopic surgery patients

“…[3132] Especially in hypoxic environments, halothane has been shown to cause more histopathological injury than does isoflurane in studies conducted on rat livers. [3334] In the present study, we eliminated the risk of a hypoxic liver by holding the MAP over 80 mmHg.…”