The effect of different mean arterial pressures on renal function during ex vivo normothermic machine perfusion of porcine kidneys: towards optimal conditions

T.M. Huijink, L.H. Venema, J.L. Hillebrands, S. P. Berger, H.G.D. Leuvenink

Wednesday 4 march 2020

16:10 - 16:20h at Joep Nicolas zaal

Parallel session: Parallel sessie VII – Basale- en Klinische abstracts

Background: In transplantation settings, machine perfusion aims to reduce the detrimental consequences of IRI. Although machine perfusion is now widely implemented, there are still knowledge gaps around rather basic aspects of machine perfusion. Perfusion pressure is one of these aspects that have not been studied thoroughly, although clinicians rely on it heavily. The aim of this study is to evaluate the effect of different mean arterial pressures on renal function and morphology, during ex vivo normothermic machine perfusion.

Methods: Porcine kidneys, obtained from a local abattoir, were subjected to 35 min of warm ischemia. After a flush of cold 1L saline, kidneys were prepared and placed on oxygenated, pressure controlled (25mmHg), hypothermic machine perfusion for 3 h and transported to the laboratory. Subsequently, kidneys were perfused normothermically for 4 h with a leucocyte depleted, blood based solution. Kidneys were divided into three groups (n=6) with mean arterial pressures (MAPs) of either 55, 75 or 95 mmHg. Perfusate, urine and tissue samples were taken during and after machine perfusion to assess both renal function and morphology.

Results: No significant differences between groups were observed with regard to flow, intrarenal resistance, creatinine clearance or urine production. Moreover, oxygen consumption and oxygen-demanding processes such as fractional sodium excretion were not different between groups. In all groups a decreasing oxygen-consumption trend is seen over time. Total urine protein concentration, reflecting disrupted glomerular integrity, was not significantly different between groups either.

Conclusions: Despite different MAPs during normothermic machine perfusion, no differences in perfusion or functional parameters were observed, which indicate that during NMP vasoreactive processes are not present. The observed trend of decreasing oxygen consumption indicates mitochondrial malfunction, but needs further evaluation. Whether different MAPs also affect morphology will also be examined.