10 °C Storage for the Preservation of Pig Kidney Grafts: A Porcine Autotransplant Model

Optimization of organ storage is essential to improve outcomes in kidney transplantation. Recent studies in lung transplantation highlight the impact of temperature on organ preservation, leading to a shift from traditional 4 °C "on-ice" storage toward 10 °C. We sought to determine whether these findings extend to kidney transplantation using 2 distinct porcine autotransplant models.

The initial donation after circulatory death model consisted of 30 min of warm ischemia followed by a brief 7.5 h storage on-ice (n = 5) or at 10 °C (n = 5). Grafts were retransplanted, the contralateral kidney was removed, and participants were followed up for 3 d. A second model simulating donation after brain death compared 24-h storage at 10 °C (n = 3) to a contemporaneous standard ice storage cohort (n = 3), followed by transplant, contralateral nephrectomy, and 7-d follow-up.

The first model revealed discrete differences in creatinine, blood urea nitrogen, sodium, potassium, urine output, creatinine clearance, and fractional sodium excretion favoring 10 °C (P > 0.05). Histology revealed reduced tubular injury (P = 0.03) and interstitial inflammation (P < 0.05) in the 10 °C group. Urinary neutrophil gelatin-associated lipocalin and thiobarbituric acid reactive substances were also reduced at 10 °C in the postoperative period (P > 0.05). However, prolonged 24-h storage at 10 °C did not benefit kidney function, with significantly worse creatinine and blood urea nitrogen values over time (P < 0.05).

The results of this initial study suggest that 10 °C storage may offer a modest protective effect in a short-storage porcine donation after circulatory death autotransplantation model; however, no benefit was demonstrated with prolonged storage, suggesting that any potential effects may be organ- and preservation solution-specific, as well as time-dependent. Larger studies are needed to draw more definitive conclusions.