Effects of In Vivo Hepatic Ischemia-Reperfusion Injury on the Hepatobiliary Disposition of Rhodamine 123 and its Metabolites in Isolated Perfused Rat Livers

Abstract

-Purpose.A few studies have shown that normothermic hepatic ischemia-reperfusion (IR) injury may affect the mRNA and/or protein levels of canalicular transporters P-glycoprotein (P-gp) and multidrug resistance-associated protein 2 (Mrp2). However, the effects of the injury on the functions of these canalicular transporters with respect to the biliary excretion of drugs remain largely unknown. Therefore, the purpose of this study was to investigate the effects of warm hepatic IR on the hepatobiliary disposition of rhodamine 123 (RH-123), a P-gp substrate, and its glucuronidated metabolite (RH-Glu), an Mrp2 substrate, in rats. Methods. Twenty four or 72 h following a 60-min partial ischemia or sham operation in rats, livers were isolated and perfused ex vivo with a constant concentration (~100 ng/mL) of RH-123. The concentration of RH-123 and its glucuronidated (RH-Glu) and deacylated (RH-110) metabolites were determined in the outlet perfusate, bile, and the liver tissue using HPLC, and relevant pharmacokinetic parameters were estimated. Results. Twentyfour-h IR caused a significant reduction in the hepatic extraction ratio of RH-123 (IR: 0.857 ± 0.078; Sham: 0.980 ± 0.017) and the biliary recovery of the parent drug and RH-Glu by 43% and 44%, respectively. The reductions in the biliary recovery were associated with significant reductions in the apparent biliary clearance of RH-123 and RH-Glu. Mass balance data showed that the formation of the glucuronidated or deacylated metabolite was not significantly affected by the 24-h IR injury. In contrast to the 24-h IR, the injury did not have any effect on the hepatobiliary disposition of RH-123 or its metabolites following 72 h of reperfusion. Conclusions. It is concluded that the pharmacokinetics of drugs that are subject to biliary excretion by the canalicular P-gp and Mrp2 transporters may be altered shortly after hepatic IR injury.

Assessing Steatotic Liver Function after Ischemia-Reperfusion Injury by In Vivo Multiphoton Imaging of Fluorescein Disposition

“…Because fluorescein is mainly metabolized in the hepatocyte to FG through glucuronidation, conjugating to a single glucuronic acid molecule (Chahal et al, 1985), it is likely that the increased metabolism (increased k met ) reflects an increased glucuronidation of fluorescein in the diseased 160 Thorling et al liver. This result is consistent with the previous report of the increased glucuronidation in obese humans (Hanley et al, 2010) and in hepatic I/R injury (Parasrampuria et al, 2012).…”

Effects of Long-Term Hepatic Ischemia-Reperfusion Injury on the Function of P-glycoprotein in vivo in Rats

“…This coincided with another study of hepatic I/R injury, where the bile flow rate was 30 % lower in the I/R group compared to sham (48). In addition, another study of I/R injury reported significantly decreased bile flow at 24 h, which returned to normal values at 72 h (20). It is possible that the decreased bile flow is a result of impaired microcirculation in the liver.…”

“…As a consequence, biliary excretion rate of Rh123 was significantly decreased at 4 h of reperfusion (p<0.05). A reduced biliary excretion rate as well as decreased recovery of Rh123 was previously reported in I/R injury at 24 h of reperfusion (20,48). The reduced biliary excretion rate found in our study may also be a consequence of posttranscriptional regulation or factors such as Pgp in vivo half-life (51,52).…”

“…Limited studies have investigated protein expression of transporters on I/R injury (11,12,18,19), however, only one recent paper has investigated the function of Pgp by examining the biliary excretion pattern of Rh123 in the isolated perfused rat liver (20). Our study adds to these reports by utilizing multiphoton microscopy (MPM) to visualize the change in intracellular drug concentration of Rh123 in space and time in vivo following I/R injury.…”

Intravital multiphoton microscopy can model uptake and excretion of fluorescein in hepatic ischemia-reperfusion injury

“…37 Another recent study also found a reduced uptake and clearance of perfused rhodamine 123 in the rat liver after I/R injury. 38 To our knowledge, we are the first to use intravital imaging to visualize and model the uptake and clearance of a fluorescent compound to assess liver function following I/R injury.…”