Trophic Factor Supplementation Protects Kidney Tubule Cells from Cold Ischemic Injury and Decreases Free Radical Production during Rewarming

Trophic factor supplementation (TFS) of University of Wisconsin (UW) solution has been previously shown to enhance kidney viability after cold storage. Here, an in vitro model was used to study the effect of TFS on oxidative stress and cell viability of primary canine kidney tubule cells. Primary canine kidney tubule cells were harvested and cultured in RK-1 media until 3-day cold ischemic storage in UW or UW + TFS. Cell viability following 3-day cold ischemic storage was measured using an esterase cleavage assay. Oxidative stress was estimated using a commercial H₂O₂ assay of cells following 3-day cold ischemic storage in UW or UW + TFS with and without rewarming in RK-1 media. A significant increase in cell viability of cells stored in UW + TFS for 3 days was measured using an esterase cleavage assay. A significant decrease in H₂O₂ was observed in cells stored in UW + TFS for 3 days and rewarmed in RK-1 for 90 min, respectively. This study is the first to show a link with use of TF in cold storage between protection of kidney tubule cell viability and significantly reduced oxidant stress during storage and reperfusion. While direct scavenging effects of TFs on ROS cannot be ruled out at this point, it seems more likely that mechanisms mediating this effect may be due to impacts on antioxidant system protein stability, expression, or through mitochondrial protection.