Liver preservation with HTK: salutary effect of hypothermic aerobiosis by either gaseous oxygen or machine perfusion

Abstract

The aim of the present study was to improve the viability of marginal livers from non-heart beating donors upon cold preservation using two different techniques for the provision of tissue aerobiosis. Livers from male Wistar rats (250-300 g bw) were harvested after 60 min of cardiac arrest, flushed via the portal vein with 20 mL of heparinized Ringer's solution and 60 mL of histidine-tryptophan-ketoglutarate (HTK) preservation solution. Control livers were then stored submerged in HTK for 24 h at 4 degrees C while other organs were subjected to aerobic conditions by either insufflation of gaseous oxygen via the venous vascular system of the cold stored organ (VSOP) or pulsatile machine perfusion (MP) with oxygenated HTK at 5 mL/min at 4 degrees C. Superoxide dismutase (SOD) (7500 IU) was added to the last 10 mL of HTK in order to prevent adverse effects of high oxygen tensions at hypothermia. Viability of the livers was assessed upon isolated perfusion in vitro with oxygenated Krebs-Henseleit buffer at constant flow. VSOP or MP, both significantly improved vascular conductivity upon reperfusion as evaluated by portal venous pressure, reduced hepatic enzyme release and led to a rise in hepatic bile production upon reperfusion. Induction of apoptosis was also looked for in tissue homogenates by Western analysis for cleavage of poly(ADP-ribose)polymerase (PARP). Expression of cleaved PARP fragment could be found in reperfused control livers but also, though to a lesser extend, after VSOP or MP. In conclusion, provision of oxygen during cold preservation significantly contributes to improve organ viability upon reperfusion and must be regarded as a useful adjunct for marginal or pre-damaged livers. HTK has been shown for the first time to be also suitable for long-term MP preservation of the liver, but, as inferred from these data, simple insufflation of gaseous O2 may be considered a feasible alternative.

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.…”

Development of a normothermic extracorporeal liver perfusion system toward improving viability and function of human extended criteria donor livers

“…Animal liver transplantation models have successfully used HMP with donation after cardiac death (DCD) livers. (8)(9)(10)(11) The major drawback of HMP is that prolonged perfusion during hypothermia may injure the sinusoidal endothelial cells due to increased vascular resistance and imposed shear stress, (12,13) so only short, 1-3 hour perfusion durations are feasible. In addition, HMP seems to offer reduced protection with marginal grafts.…”

Optimising post-conditioning time of marginal donor livers

“…Therefore, over the past years, aerobic preservation methods were investigated as an alternative to the conventional cold storage (CS). It was demonstrated that aerobic preservation via continuous oxygenated machine perfusion (MP) or venous oxygen persufflation (VSOP) are superior to classical CS in many aspects [4][5][6][7][8][9][10]. The major drawback of MP lies in its comparatively cumbersome applicability, the necessity of being timely available at the place of organ retrieval and the need of continuous surveillance thereafter.…”