Free Fatty Acid and Glucose Metabolism during Hypothermic Perfusion of Canine Kidneys

Abstract

Canine kidneys were subjected to continuous nonpulsatile perfusion using 200 ml of a perfusate containing 50 g/l albumin. When optimal oxygenation was achieved, perfusate K⁺ contents were unchanged for 24 h, indicating adequate membrane function but tended to increase thereafter. Lowered oxygen pressures resulted in significant cellular K⁺ loss during the first hours of perfusion. During oxygenated perfusion, glucose and free fatty acids (FFA) were oxidized in considerable amounts with a preferential consumption of octanoate. A capacity for long-chain FFA oxidation became obvious when the octanoate had been used up, but the amount of these FFA in the perfusate depended preferentially on FFA being liberated from tissue lipids during the 1st day of perfusion. Glucose consumption rates were highest during the first 2 days of perfusion but the subsequent reduction of the metabolic rate was not accompanied by an accumulation of lactate. Thus medium-chain FFA and glucose should be supplied to the continuously perfused kidney in hypothermia and optimal oxygenation of the perfusate should be guaranteed. However, it seems to be unnecessary to supply exogenous long-chain FFA.

Adenine Nucleotide Levels of Canine Kidneys during Hypothermic Aerobic or Anaerobic Storage in Collins’ Solution

“…The cause of this SAN reduction, which cannot be addressed to nucleotide washout as in continuous perfusion, may be a lack of substrate supply or an accumulation of wastes. The changes in ECP seem to support this interpretation: while in ROP the ECP decreased after the 24th hour, it could be held at normal values during oxygenated continuous perfusion without substrate supply for 48 h [12] and even for 72 h if glucose and free fatty acids were added to the perfusate [10,12], Adenine nucleotide contents and lactate production have been consid ered to be suitable for viability testing of preserved kidneys by several authors. Some regarded the SAN of the renal cortex to be best suited for viability testing [3,5,15,17], while others even thought that ATP values give enough information [2,6,14].…”

Current Insights into the Metabolome during Hypothermic Kidney Perfusion—A Scoping Review

“…Cooling (2-12 • C) was accomplished by a heat exchanger, ice surrounding the reservoir, or a combination of both. The majority of the circuits used pulsatile perfusion (roller, centrifugal, or peristaltic pump); continuous non-pulsatile perfusion was used in two studies [37,38]. In most studies, perfusion was pressure controlled (25 to 60 mmHg) with a maximal pressure of 30 mmHg in recent studies.…”

“…In the majority of studies, the perfusate was oxygenated (40/52; 77%), most commonly by using a membrane oxygenator (26/40; 65%) (Table S2). In these studies, a mixture of O 2 and CO 2 [17,[19][20][21][22]25,34,[40][41][42][43][44][45] or a mixture of O 2 , CO 2 , and nitrogen [26,27,38,[46][47][48][49] was given. Surface oxygenation with room air or O 2 (13/40; 33%) [20,32,37,38,[41][42][43][50][51][52][53][54][55] was also used.…”

“…In these studies, a mixture of O 2 and CO 2 [17,[19][20][21][22]25,34,[40][41][42][43][44][45] or a mixture of O 2 , CO 2 , and nitrogen [26,27,38,[46][47][48][49] was given. Surface oxygenation with room air or O 2 (13/40; 33%) [20,32,37,38,[41][42][43][50][51][52][53][54][55] was also used. In one article (3%), bubble and surface oxygenation were combined [20].…”

“…Interestingly, Slaattelid et al also found a different perfusate glucose uptake and release pattern when glucose was administered intravenously before kidney procurement [27]. Three studies found a decrease in tissue glucose regardless of whether the perfusion medium was glucose-rich or -poor [27,37,38]. Tracer studies showed active glucose metabolism, with the detection of 14 C-CO 2 and 14 Clactate [27,[46][47][48].…”