Normothermic blood perfusion of isolated rabbit kidneys. III. In vitro physiology of kidneys after perfusion with Euro-Collins solution or 7.5 M cryoprotectant (VS4).

Cryopreservation of solid organs might be possible using a mixture of cell-permeable agents, cryoprotectants (CPA), which are designed to completely preclude ice crystal formation during cooling to cryogenic temperatures. The effects of a specific prototype solution (VS4) were evaluated by normothermic blood perfusion in vitro. Rabbit kidneys were divided into three groups: untreated controls ( n=7), Euro-Collins (EC)-perfused controls ( n=6) and VS4 (49%, w/v) CPA-perfused kidneys ( n=7). After a 2-h blood perfusion, five of the seven CPA-perfused kidneys developed polyuria (0.21 mlxmin(-1)xg(-1)) relative to untreated controls (0.07 mlxmin(-1)xg(-1)) or EC-perfused kidneys (0.06 mlxmin(-1)xg(-1)), owing to the lower reabsorption of water (34.3%), Na(+) (34.2%) and glucose (35.6%). Furthermore, two kidneys were non-functional with virtually no urine production. Reduced tubular function was associated with reduced oxygen consumption (3.6 versus 2.3 versus 2.0 micromolexmin(-1)xg(-1) for controls, EC- and CPA-perfused kidneys, respectively) and increased weight gain (17% versus 20% versus 30%, respectively) after blood perfusion. Therefore, the current results provide insight into both the physiological effects of VS4 and the limits of reversibility of renal pathophysiological states. Our results also indicate that in vitro monitoring of oxygen consumption and weight gain of perfused organs could be used as predictors of renal function.

Using tandem scanning confocal microscopy to predict the status of donor kidneys.

Tandem scanning confocal microscopy (TSCM) is a noninvasive form of vital microscopy that can be used to evaluate superficial uriniferous tubules in living kidneys. Because TSCM has a number of advantages over conventional microscopic examination of renal biopsies, the present study was undertaken to determine whether the histopathological images obtained by TSCM correlate with post-transplant renal function. The kidneys of New Zealand male rabbits were harvested, flushed with Euro-Collins solution, and stored at 0-2 degrees C for periods of 24, 48, 67 and 72 h prior to transplantation. TSCM observation of the kidneys prior to their transplantation revealed characteristic histopathological changes of the superficial proximal convoluted tubules that correlated closely with subsequent post-transplant renal function. These observations indicate that TSCM may be of significant value in evaluating the status of donor kidneys prior to their transplantation.