Metabolism in the Hypothermically Perfused Dog Kidney

Abstract

The incorporation of [¹⁴C]leucine and [¹⁴C]threonine into kidney cortex proteins was studied during 6 days’ hypothermic perfusion of dog kidneys at 8–10 °C and during in vitro incubation of dog kidney cortex slices at 37 °C. Leucine carbon was incorporated into proteins at a higher rate than threonine carbon both during in vitro incubation of kidney cortex slices and during hypothermic kidney perfusion. The incorporation of leucine and threonine during hypothermic perfusion was linear for 6 days but 50–100 times lower than the incorporation of leucine and threonine in kidney cortex slices at 37 °C. During hypothermic perfusion there was a decrease in specific activity of leucine and threonine in the perfusate corresponding to a degradation of proteins which was greater than protein synthesis as calculated from the incorporation of label into proteins. Leucine carbon was recovered in CO₂ during hypothermic perfusion and in vitro incubation of kidney cortex slices at 37 °C. The incorporation of threonine carbon into CO₂ was about 10% of the corresponding value for leucine both during hypothermic kidney perfusion and during in vitro incubation of kidney cortex slices at 37 °C. It is concluded that there is a turnover of kidney proteins during hypothermic perfusion with a perfusate containing amino acids.

Unraveling metabolism during kidney perfusion using tracer studies: a systematic review

“…Baseline characteristics (animal strain, sex, weight, or diet) were mostly well described. In five studies (5/30, 17%), the different groups did not have similar baseline characteristics or analyses were not adjusted for confounders 35,38,48,51,55 . Performance bias was rated as high in three studies, 31,34,40 low in one study, 42 and unclear in all others (26/30, 87%) 27–30,32,33,35–39,41,43–55 .…”

“…Performance bias was rated as high in three studies, 31,34,40 low in one study, 42 and unclear in all others (26/30, 87%) 27–30,32,33,35–39,41,43–55 . Random housing of animals was not performed in two studies (2/30, 7%) 31,40 and was not reported in the remaining studies 27–30,32–39,41–56 . Due to the nature of the paired study set‐up used by Patel et al, animal caregivers were automatically blinded 42 .…”

“… 38 Although Skrede et al mentioned the use of an oxygenator, no further details were given 48 . In pigs, Patel et al investigated whether adding oxygen (95%) versus exposure to air (21%) via a membrane oxygenator would result in metabolic changes 38,48 . In the study of Nath et al, no additional oxygen was added to the circuit 41 .…”

“…The length of perfusion ranged from 18 h 42 to 6 days. 37,38,44 Lundstam et al set the perfusion target pressure at 60 mm Hg. No (ischemic) damage to the kidneys was mentioned.…”

“…38,48 In the study of Nath et al, no additional oxygen was added to the circuit. 41 In both pig studies, Kidney Perfusion Solution-1, 41,42 a specific hypothermic perfusion solution designed for the preservation of human kidneys for transplantation, or human serum albumin 37,38,44,48 were used as priming solution (Table 3). None of these studies added extra amino acidsn to the perfusate.…”