A novel ex-vivo porcine renal xenotransplantation model using a pulsatile machine preservation system.

BACKGROUND: Animal models to investigate pathophysiology and xenotransplantation require complex techniques and significant animal utilization. The aim of the study was to develop a reliable ex-vivo technique to test xenotransplant interventions. MATERIAL/METHODS: Miniature Swine being utilized for a nonsurvival study acted as donor animals. Kidneys were flushed and rapidly explanted and chilled to 4°C. Kidneys were assigned to be the control (CK) (n=3) and the mate were used as a Xenograft Kidneys (XK) (n=3). Kidneys were perfused on separate Waters RM 3 perfusion devices. Perfusion temperature was 35-37°C and pressure was 100-110/60-70 mmHg at 60 pulses per minute. CKs were reperfused with autologous blood collected at the time of organ procurement. XKs were reperfused using freshly donated whole human blood. Physical characteristics, urine output were recorded. Core needle biopsies were obtained and examined by a blinded pathologist for evidence of antibody mediated rejection. RESULTS: XK kidneys demonstrated homogenous reperfusion which rapidly became patchy at 5-7 minutes. XK kidneys had become complete black and thrombosed by 60-70 minutes. XK biopsies demonstrated peritubular capillaritis. CK kidneys demonstrated homogenous reperfusion and urine production. H&E stain of CKs only demonstrated nonspecific inflammation. CONCLUSIONS: Our ex-vivo porcine xenotransplant model shows early promise as a tool for studying Xeno- associated hyperacute rejection. This technique saves resources and animal utilization.

Hypothermic machine preservation attenuates ischemia/reperfusion markers after liver transplantation: preliminary results.

BACKGROUND: Hypothermic machine perfusion (HMP) has shown significant benefits in renal transplantation but is still in its infancy in liver transplantation. Potential benefits include diminished preservation injury and improved early graft function. METHODS: We analyzed liver tissue and effluent collected during our Phase 1 trial of liver HMP. Liver allografts underwent HMP for 4-7 h using dual centrifugal perfusion with Vasosol solution at 4-8°C were transplanted and compared with cold stored (CS) transplant controls. Histology, reverse transcription-polymerase chain reaction (RT-PCR), and immunohistochemistry on liver biopsies compared histology and expression of early proinflammatory cytokines, IL-8 and TNF-α, and intracellular adhesion molecule-1 (ICAM-1). Gel electrophoresis was used to evaluate effluent protein content representing residual metabolism. RESULTS: We saw no differences between HMP and CS in early histologic findings after reperfusion. RT-PCR of reperfusion biopsy samples in the CS group showed high expression of proinflammatory cytokines and ICAM-1. This up-regulation was significantly attenuated by HMP (ICAM-1; P = 0.0152) (IL-8; P = 0.0014) (TNF-α; P = 0.0284). This was confirmed with immunohistochemistry. Albumin was identified in the perfusate throughout HMP. CONCLUSIONS: HMP significantly reduced proinflammatory cytokine expression compared with CS controls. Further studies of human liver HMP with detailed molecular investigations are now warranted to elucidate benefits of HMP in liver transplantation.