Introduction: Donation after brain death (BD) is still the main source of organs for transplant and several strategies have been developed to improve organ quality. Machine perfusion is a tool to assess function and allows organs to be treated before transplantation. Also, the use of hormonal replacement in the donor is common practice with positive results. In that sense, our aim was to investigate the use of combined administration of methylprednisolone (MP) and 17β-estradiol (E2) during isolated kidney perfusion (IPK) in BD animals.
Methods: Females and males Wistar rats were submitted to BD and maintained for 4h. After 4h of BD, animals were exsanguinated and a whole-body flush was performed using 40 ml of cold saline (NaCl 0,9%). In the same animal, the right kidney (RK – no IPK) was removed and stored, while the left kidney (LK – with IPK) had the ureter and the renal artery cannulated, and flushed with 5 ml of cold saline. The LK was then taken directly to the IPK system for 90 minutes. Experimental groups were performed in both male and female: BD+IPK (without treatment) and BD+IPK+T (with treatment (T): MP, 40 mg; E2: 5 µg/mL added to the perfusate). Perfusion was performed with a constant pressure of 100 mmHg, using William’s Medium E supplemented with HEPES, creatinine and albumin as perfusate. Perfusate and urine were collected and flow measurements were recorded. After IPK, the LK was stored. IL-6 was measured in RK and LK homogenates and perfusate samples. Creatinine was also quantified in perfusate and urine samples. All stored kidneys were stained for morphological analysis.
Results: All groups presented reduced concentrations of IL-6 in the LK in comparison to respective RK, regardless of treatment (p<0.0001). Interestingly, in perfusate, female BD+IPK+T presented lower levels of IL-6 in comparison to female BD+IPK (p=0.0195), while no difference was observed in the male groups. Female BD+IPK+T also presented reduced perfusion flow in comparison to all other groups (p<0.0001). Creatinine clearance was reduced in both treated and non-treated males in comparison to respective female groups (p=0.0012). In regard to renal morphology, all groups presented an increased glomerular space in the LK in comparison to RK (p<0.0001). On the other hand, necrosis of the proximal (p<0.0001) and distal (p=0.0001) tubule was reduced on treated and non-treated perfused kidneys in comparison to kidneys that were not placed on the IPK.
Conclusion: Our data point to an improvement on renal inflammation after IPK, specially on the female treated group, marked by the reduction of IL-6 in perfusate samples. These results could suggest that the associated treatment of MP and E2 is beneficial to female subjects and could arise as a treatment strategy to improve organ quality during kidney perfusion.