Does cardiac impairment develop in ischemic renal surgery in rats depending on the reperfusion time?

BackgroundRenal dysfunction is known to cause heart failure. However, renal dysfunction associated with kidney surgeries (mediated by reperfusion injury) that affects the cardiac physiological function, especially during the recovery and repair phase of renal surgery is unknown.MethodMale Wistar rats (238±18g) were subjected to renal sham and ischemia-reperfusion (IR-bilateral clamping for 15 minutes/45 minutes and reperfusion for 24 hours/ 48 hours/ 7 days) surgeries. At the end of the experiment, the heart was isolated from the animal (to exclude neurohormonal influence) and perfused for 60 minutes with Krebs-Hanseleit buffer to study the physiological changes.ResultRenal artery bilateral occlusion for 45 minutes that creates ischemia, followed by 24 hours of reperfusion did not impart any significant cardiac physiological functional decline but 48 hours of reperfusion exhibited a significant decline in cardiac hemodynamic indices (Rate pressure product in x104 mmHg*beats/min: Sham- 3.53 ± 0.19, I45_R48- 2.82 ± 0.21) with mild tissue injury. However, 7 days of reperfusion inflict significant physiological decline (Rate pressure product in x104 mmHg*beats/min - 2.5 ± 0.14) and tissue injury (Injury score- 4±1.5) in isolated rat hearts. Interestingly, when the renal artery bilateral occlusion time was reduced to 15 minutes the changes in the hearts were negligible after 7 days. Cellular level exploration reveals a positive relation between functional deterioration of mitochondria and elevated mitochondrial oxidative stress and inflammation with cardiac physiological decline and injury linked with renal ischemia-reperfusion surgeryConclusionCardiac functional decline associated with renal surgery is manifested during renal repair or recovery. This decline depends on cardiac mitochondrial health, which is negatively influenced by the renal IR mediators and kidney function