A NEW METHOD TO EVALUATE THE VIABILITY OF PRESERVED KIDNEY BY MYO-INOSITOL LEVELS IN THE EARLY EFFLUENT PERFUSATE

Abstract

The correct prediction of the viability of the isolated or preserved kidney is very important in cadaver transplantation. At present, while there are various methods for evaluating the viability of renal graft, none is complete. Furthermore, the assessment of its viability is frequently based on the duration of warm or cold ischemia in simple cold storage. Therefore, an accurate, rapid and complete method for the prediction of renal viability is desirable.
The author recently found that myo-inositol, a kind of cyclic polyol contained abundantly in the organ, is plentiful in the early effluent perfusate washed out from the preserved kidney. Based on these findings, attempts were made to develop for evaluating the viability of the preserved kidney by measuring the free myo-inositol (F. m-I) levels in the early effluent perfusate (EEP).
Herewith the satisfactory results of my experiments, in vitro and in auto-transplantation of the canine kidney, and clinical renal transplantation by the method are reported.
The canine kidney was kept in ischemic condition for various periods at 4°C or 37°C and it was washed out with 4°C lactated Ringer's solution (200ml). The first effluent perfusate of 25ml (EEP) was collected. As for the perfusate, F. m-I was trimethylsililated and measured by gas-chromatography using a 2m column of 5% ucon coated.
In vitro, the relationship between F. m-I levels (Y) and cold ischemic time (X, hrs) for kidney was Y=0.03X²-0.04X+17.72 (μg/ml), the coefficient of correlation (r) being 0.858. The relationship between F. m-I levels (Y) and warm ischemic time (X, hrs) came to Y=17.9X²-16.5X+15.6 (μg/ml), r=0.808, showing that F. m-I levels were correlated markedly with the ischemic time of the preserved kidney.
In auto-transplantation, the animals were classificated into the following three groups according to the graft function. I, the S - Cr is less than 5mg/dl. II, the S - Cr rises up to ca 10ml/dl but thereafter falls off gradually. III, the S - Cr rises transiently and animals die within a week. The mean F. m-I levels in EEP of those groups were I; 15.6±2.2 II; 32.2±3.5 and III; 67.1±14.5 μg/ml (mean±S. E), respectively. And the relationship between F. m-I in EEP and max. S-Cr levels of animals was Y=0.168X+1.70, r=0.815. In control kidneys, the mean F. m -I level in supernate of whole, cortex and medulla were 9.54±1.28, 2.85±0.38 and 21.20±2.32 μg/mg (mean±S. D). On the other hand, in a 3hr warm ischemic kidney, the mean F. m-I level in supernate of those were 5.90±1.07, 2.63±0.36 and 16.00±2.17μg/mg, respectively. F. m-I in renal tissue is contained mainly in its medulla. And F. m-I in renal medulla declines with long ischemia, although that of renal cortex dose not change.
In clinical renal transplantation, the mean F. m-I levels in total effluent perfusate of living and cadaver donor graft were 509.1±245.7 and 1138±130μg (mean±S. D). The mean F. m-I levels in total effluent perfusate per 1g of graft kidney were 3.08±1.35 and 7.57±1.40μg/g (mean±S. D). The mean F. m-I levels in total effluent perfusate of early postoperative good and bad function grafts were 483±231 and 1079±153μg.
The mean F. m-I levels in total effluent perfusate in per 1g of graft kidney were 2.95±1.28 and 6.95±1.62μg/g, respectively.
In summary, F. m-I levels in EEP were markedly correlated with the duration of cold and warm ischemia, with the renal graft function after auto - and clinical transplantation, suggesting that preserved kidney viability may be predicted by EEP - F. m-I determination.