Optimisation of Bile Production during Normothermic Preservation of Porcine Livers

Abstract

Machine perfusion of livers may provide a mechanism for extended preservation of marginal donor organs before transplantation, as well as a method for viability assessment. It has proved possible in a series of experimental porcine liver perfusions to maintain liver viability for up to 72 h. However, a reduction in bile production with associated histological evidence of cholestasis was seen after 10 h of perfusion, damaging the biliary canaliculi during the preservation period and leaving these organs in an unacceptable condition for transplantation. It was proposed that reduction in bile production was the result of a relentless depletion of available bile salts, gut recirculation not being possible and de-novo synthesis being unable to keep up with loss. This was proved by measuring porcine native bile acids within serial perfusate and bile samples using gas chromatography mass spectrophotometry. It was shown that all three native pig bile acids were decreased to 30% of their original value by 20 h of unsupplemented perfusion. An infusion of taurocholate managed to maintain bile production at physiological levels throughout the 20-h period (8 mL/h ∫ 0.75). It was successfully incorporated by the porcine livers into bile. We propose to use this circuit as a novel means of preserving donor livers for transplantation in which the organ is maintained at normal body temperature and perfused with blood. This will reduce ischaemia reperfusion injury and may enable prolonged preservation. The modification described ensures optimal bile production over the entire perfusion period, preventing inspissation and subsequent damage to the canaliculus.

Role of perfusion medium, oxygen and rheology for endoplasmic reticulum stress-induced cell death after hypothermic machine preservation of the liver

“…Consistent with reports from previous studies and that from our laboratory [11,22,23], it was found that HMP significantly improves hepatic parenchymal enzyme release and functional recovery upon reperfusion. Beyond this, we could provide evidence that oxygenation during ex vivo storage by machine perfusion with either preservation medium significantly improved mitochondrial integrity, compared to simple CS, and largely attenuated cleavage of caspase 9, hallmark of the initiation of the intrinsic pathway of apoptosis.…”

Comparing Normothermic Machine Perfusion Preservation With Different Perfusates on Porcine Livers From Donors After Circulatory Death

“…These findings are important for several reasons. First, NMP is rapidly becoming the subject of preclinical and clinical research (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23). Second, different research groups have used various perfusion protocols but none have compared their efficacy.…”

“…Numerous studies have demonstrated the advantage of NMP over CS in the preservation of DCD livers (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18), suggesting that NMP may greatly benefit the practice of liver transplantation. conducted using whole blood (WB) (9)(10)(11)(19)(20)(21). The same group recently introduced NMP in human liver transplantation using blood and additives during perfusion (18).…”

Criteria for Viability Assessment of Discarded Human Donor Livers During Ex-Vivo Normothermic Machine Perfusion.

“…Therefore, we do not believe the addition of bile salts is necessary when livers are perfused for less than 10 hours. In fact, hydrophobic bile salts have been demonstrated to play a role in bile duct epithelial injury after liver transplantation and this could be considered an additional argument not to add bile salts to the perfusion fluid [19], [20], [21], [22]. On the other hand, due to the strong choleric effect of bile salts, bile production during ex vivo NMP will be higher when bile salts are added to the perfusion fluid.…”