Glucose Supplementation Does Not Interfere With Fasting-Induced Protection Against Renal Ischemia/Reperfusion Injury in Mice

Background. Preoperative fasting induces robust protection against renal ischemia/reperfusion (I/R) injury in mice but is considered overcautious and possibly detrimental for postoperative recovery in humans. Furthermore, fasting seems to conflict with reported benefits of preoperative nutritional enhancement with carbohydrate-rich drinks. Here, we investigated whether preoperative ingestion of a glucose solution interferes with fasting-induced protection against renal I/R injury. Methods. Mice were randomized into the following groups: fasted for 3 days with access to water (fasted) or a glucose solution (fasted + glc) and fed ad libitum with water (fed) or a glucose solution (fed + glc). After induction of bilateral renal I/R injury, all animals had free access to food and water. Calorie intake, body weight, insulin sensitivity, kidney function, and animal survival were determined. Results. Fed + glc mice had a comparable daily calorie intake as fed mice, but 50% of those calories were obtained from the glucose solution. Fasted + glc mice had a daily calorie intake of approximately 75% of the intake of both fed groups. This largely prevented the substantial body weight loss seen in fasted animals. Preoperative insulin sensitivity was significantly improved in fasted + glc mice versus fed mice. After I/R injury, kidney function and animal survival were superior in both fasted groups. Conclusions. The benefits of fasting and preoperative nutritional enhancement with carbohydrates are not mutually exclusive and may be a clinically feasible regimen to protect against renal I/R injury.