Normothermic Ex Vivo Liver Perfusion Prevents Intrahepatic Platelet Sequestration After Liver Transplantation.

BACKGROUND: The detrimental role of platelets in sinusoidal endothelial cell (SEC) injury during liver transplantation (LT) has been previously addressed after static cold storage (SCS), however, it is currently unknown after normothermic ex vivo liver perfusion (NEVLP). METHODS: Pig LT was performed with livers from heart-beating donors or donation after circulatory death (DCD) donors subjected to SCS or NEVLP (n = 5/group). RESULTS: All pigs except for 1 (DCD-SCS-group) survived 4 days. The heart-beating donor- and DCD-NEVLP-groups showed significantly lower aspartate transaminase-levels compared with the SCS-groups 3 hours post-LT (P = 0.006), on postoperative day (POD) 2 (P = 0.005), POD3 (P = 0.007), and on POD4 (P = 0.012). Post-LT total platelet count recovered faster in the NEVLP than in the SCS-groups at 12 hours (P = 0.023) and 24 hours (P = 0.0038). Intrahepatic sequestration of platelets was significantly higher in the SCS-groups 3 hours postreperfusion and correlated with severity of SEC injury. In both SCS-groups, levels of tumor growth factor-ß were higher 3 hours post-LT, on POD1 and on POD3. Moreover, platelet factor 4 levels and platelet-derived extracellular vesicles were increased in the SCS-groups. Hyaluronic acid levels were significantly higher in the SCS-groups, indicating a higher grade of endothelial cell dysfunction. Platelet inhibition achieved by pretreatment with clopidogrel (n = 3) partly reversed the detrimental effects on SEC injury and therefore provided further evidence of the important role of platelets in ischemia/reperfusion injury and SEC injury. CONCLUSIONS: Normothermic perfusion of liver grafts before transplantation effectively reduced platelet aggregation and SEC injury, which translated into an improved posttransplant organ function.

Normothermic Ex Vivo Kidney Perfusion Improves Early DCD Graft Function Compared With Hypothermic Machine Perfusion and Static Cold Storage.

BACKGROUND: Better preservation strategies for the storage of donation after circulatory death grafts are essential to improve graft function and to increase the kidney donor pool. We compared continuous normothermic ex vivo kidney perfusion (NEVKP) with hypothermic anoxic machine perfusion (HAMP) and static cold storage (SCS) in a porcine kidney autotransplantation model. METHODS: Porcine kidneys were exposed to 30 minutes of warm ischemia and then reimplanted following either 16 hours of either SCS, HAMP (LifePort 1.0), or NEVKP before autotransplantation (n = 5 per group). The contralateral kidney was removed. Animals were followed for 8 days. RESULTS: Grafts preserved by NEVKP demonstrated improved function with more rapid recovery compared with HAMP and SCS (mean peak serum creatinine: 3.66 ± 1.33 mg/dL [postoperative d 1 [(POD1)], 8.82 ± 3.17 mg/dL [POD2], and 12.90 ± 2.19 mg/dL [POD3], respectively). The NEVKP group demonstrated significantly increased creatinine clearance calculated on POD3 (63.6 ± 19.0 mL/min) compared with HAMP (13.5 ± 10.3 mL/min, P = 0.001) and SCS (4.0 ± 2.6 mL/min, P = 0.001). Histopathologic injury scores on POD8 were lower in both perfused groups (NEVKP and HAMP, score: 1-1.5) compared with SCS (score: 1-3, P = 0.3), without reaching statistical significance. CONCLUSIONS: NEVKP storage significantly improved early kidney function compared with both cold preservation strategies, although HAMP also demonstrates improvement over SCS. NEVKP may represent a novel, superior preservation option for donation after circulatory death renal grafts compared with conventional hypothermic methods.

Normothermic Ex Vivo Kidney Perfusion Reduces Warm Ischemic Injury of Porcine Kidney Grafts Retrieved After Circulatory Death.

BACKGROUND: Cold storage is poorly tolerated by kidney grafts retrieved after donation after circulatory death. It has been determined that normothermic ex vivo kidney perfusion (NEVKP) preservation decreases injury by minimizing cold ischemic storage. The impact of NEVKP on warm ischemic injury is unknown. METHODS: We compared pig kidneys retrieved after 30 minutes warm ischemia and immediate transplantation (no-preservation) with grafts that were exposed to 30 minutes of warm ischemia plus 8-hour NEVKP or plus 8-hour static cold storage (SCS). RESULTS: After transplantation, the NEVKP group demonstrated lower daily serum creatinine levels indicating better early graft function compared with no-preservation (P = 0.02) or SCS group (P < 0.001). In addition, NEVKP preserved grafts had a significantly lower grade of tubular injury and interstitial inflammation 30 minutes after reperfusion compared to grafts without any storage (injury score, NEVKP 1-2 vs no-preservation, 2-2, P = 0.029; inflammation score, NEVKP, 0-0.5 vs no-preservation, 1-2; P = 0.002), although it did not reach significance level when compared to the SCS group (injury score, 1-2, P = 0.071; inflammation score, 1-1; P = 0.071). Regeneration was assessed 30 minutes after reperfusion by Ki-67 staining. The NEVKP group demonstrated significantly higher number of Ki-67-positive cells: 9.2 ± 3.7 when compared with SCS group (3.9 ± 1.0, P = 0.015) and no-preservation group (4.2 ± 0.7, P = 0.04). CONCLUSIONS: In this porcine model of donation after circulatory death kidney transplantation NEVKP reduced kidney injury and improved graft function when compared with no-preservation. The results suggest that NEVKP does not cause additional damage to grafts during the preservation period, but may reverse the negative effects of warm ischemic insult itself and promotes regeneration.

Eight-Hour Continuous Normothermic Ex Vivo Kidney Perfusion Is a Safe Preservation Technique for Kidney Transplantation: A New Opportunity for the Storage, Assessment, and Repair of Kidney Grafts.

BACKGROUND: Hypothermic kidney storage causes preservation injury and is poorly tolerated by renal grafts. We investigated whether static cold storage (SCS) can be safely replaced with a novel technique of pressure-controlled normothermic ex vivo kidney perfusion (NEVKP) in heart-beating donor kidney transplantation. METHODS: Right kidneys were removed from 30 kg Yorkshire pigs in a model of heart-beating donation and either preserved in cold histidine-tryptophan-ketoglutarate solution for 8 hours (n = 5), or subjected to 8 hours of pressure-controlled NEVKP (n = 5) followed by renal heterotopic autotransplantation. RESULTS: During NEVKP, physiologic perfusion conditions were maintained with low intrarenal resistance and normal electrolyte and pH parameters. Aspartate aminotransferase and lactate dehydrogenase as injury markers were below the detectable analyzer range (<4 and <100 U/L, respectively). Perfusate lactate concentration decreased from baseline until the end of perfusion (10.38 ± 0.76 mmol/L vs 1.22 ± 0.26 mmol/L; P < 0.001). Posttransplantation, animals transplanted with NEVKP versus SCS grafts demonstrated similar serum creatinine peak levels (NEVKP, 2.0 ± 0.5 vs SCS 2.7 ± 0.7 mg/dL; P = 0.11) and creatinine clearance on day 10 (NEVKP, 65.9 ± 18.8 mL/min vs SCS 61.2 ± 15.6 mL/min; P = 0.74). After 10 days of follow-up, animals transplanted with NEVKP grafts had serum creatinine and blood urea nitrogen values comparable to their basal levels (P = 0.49 and P = 0.59), whereas animals transplanted with SCS grafts had persistently elevated serum creatinine and blood urea nitrogen when compared with basal levels (P = 0.01 and P = 0.03). CONCLUSIONS: Continuous pressure-controlled NEVKP is feasible and safe in good quality heart-beating donor kidney grafts. It maintains a physiologic environment and excellent graft function ex vivo during preservation without causing graft injury.