The Interleukin 4 Receptor-α Potentiates the Effect of Oncostatin M Receptor on the Release of FGF23 by Cardiomyocytes

are combined, there are concerns regarding delays to institution of liver cold preservation. The aim of this study was to develop a combined DCD heart and liver retrieval protocol in a pig model with subsequent normothermic machine perfusion (NMP) of both organs to mitigate warm ischemic damage. Methods: Pigs (n= 12; 60-70 kg) were anesthetised. Baseline observations were recorded. After sternotomy, and laparotomy, ventilatory support was withdrawn to mimic DCD conditions. Death was defined as equalisation of central venous and mean arterial pressures. After a 5-minute standoff period, 1.5-2 L blood was collected from a right atrial cannula then a cardiac preservation flush (4°C) commenced via the proximal ascending aorta. The inferior vena cava was cut to vent the organs. The thoracic cavity was kept cold with saline ice slush. The heart was explanted and prepared on back-table for NMP. Liver preservation was begun immediately after blood collection by cold preservation solution flush via the infra-renal aorta and portal vein. The hepatic artery, portal vein and common bile duct were transected, and the liver explanted for back-table NMP preparation. Results: Warm ischaemic time (WIT) and back-table time (BTT) was 21 + 5 and 29 + 6 min for the heart; 20 + 6 (commencement of flush) and 33 + 19 min for the liver. The average blood volume collected was 1.6 L: 1:1 dilution with Krebs resulted in significant hemodilution (from 23 + 5% to 15 + 6%) and hypocalcemia (1.30 + 0.15 to 0.64 + 0.32 mM). This resulted in sub-optimal cardiac contractile recovery despite a favourable lactate profile. Liver enzyme release, bile production, and lactate and pH profiles were favourable during the first 4-6 hours of NMP but deteriorated thereafter. Conclusion: Heart and liver retrieval under standard DCD protocol is possible without excessively extending the WIT for either organ. However, there is insufficient donor blood to support NMP of both organs.