Alternative approaches for preservation methods are being studied to extend preservation time and minimize damage. This can enable the use of organs that are being discarded, especially donation after cardiac death (DCD) organs. Preventing complete energy depletion of the organ by providing gaseous oxygen using persufflation has the potential to prevent ischemic damage that occurs during and after preservation. For this study, kidneys from porcine donors were persufflated at hypothermic conditions while the other served as a static cold storage control, and subnormothermic liquid perfusion was performed for organ flushing and quality assessments.
Porcine kidneys were procured post euthanasia to mimic a DCD model. After the isolated kidneys were exposed to 30 minutes of warm ischemia time (WIT), they were flushed with SPS-1 and preserved at 4°C for 24 hours in their respective conditions. After the preservation period, the organs were gradually rewarmed for 30 minutes to subnormothermic temperatures. Whole organ oxygen consumption rate (WOOCR) and glomerular filtration rate (GFR) were measured at 25°C to assess renal viability and function. Renal perfusate and biopsies were collected post preservation to evaluate renal damage using molecular analyses, biomarkers and histology.
Results show significantly higher WOOCR of 281.8 nmol/(min*g) in the persufflated kidney compared to 225.5 nmol/(min*g) of the static cold storage control. The GFR was on average higher in the persufflated kidney at 17.7 ml/min and 3.67 ml/min in the cold storage group. Accumulated lactate levels overnight were significantly higher in the cold storage group at 3.17 nmol/L and 1.5 nmol/L in the persufflated group. Glutathione s-transferase levels were on average higher in the cold storage kidneys at 1.24 ug/ml with 1.01 ug/ml in the persufflated kidneys. Hematoxylin and eosin stained renal biopsies show that static cold storage kidneys on average exhibit more renal damage such as tubular epithelial necrosis, nephritis, tubulitis and multifocal, subcortical early infarct.
Persufflated kidneys trend towards having more viable, oxygen consuming tissue and increased filtration activity and less indication of renal damage post preservation. Persufflation is a promising tool that has the potential to find a niche as a preservation method, especially since organs with a wide range of cold and warm ischemic damage are being used for transplantation.