Comparison of the Outcome of Kidney Transplant After Pulsatile or Continuous Ex Vivo Hypothermic Machine Perfusion of Kidneys Donated After Cardiac Death: Analysis of Kidney Pairs.

BACKGROUND: Hypothermic machine perfusion is used to improve renal perfusion and reduce the rate of early and late graft dysfunction. It has been used in our unit since 2001. It has 2 modes of flow: continuous or pulsatile. The aim of this study is to compare the modes of perfusion in terms of perfusion-related parameters, graft survival, and estimated glomerular filtration rate. METHODS: All donation after cardiac death kidneys between 2002 and 2014 were reviewed. A total of 64 pairs of kidneys were identified of which one kidney underwent pulsatile and the other continuous perfusion. Machine parameters including resistance and perfusion flow index levels at 0, 1, 2, 3, and 4 hours were recorded and glutathione S-transferase was measured in perfusate. Estimated glomerular filtration rate from the first week of transplant until the fifth year and graft survival rates were determined. RESULTS: Machine parameters were similar at all time points. Estimated glomerular filtration rates and graft survival were the same irrespective of perfusion mode. CONCLUSION: Pulsatile perfusion may be regarded as more physiological. However, we could not identify difference in outcome following transplant of kidneys from the same donor that had been perfused under pulsatile or continuous conditions.

Behaviour of transplanted tumours and role of matching in rejection.

BACKGROUND: Tumour transfer/development is one of the more serious risks associated with transplantation. The behaviour of a tumour can be unpredictable in immunosuppressed recipients. We report a highly sensitive method to monitor tumour behaviour in real time in a rodent tumour transplant model. This paper also explores the effect of MHC matching on tumour growth among control and immunosuppressed hosts. METHODS: Luciferase expressing Wistar rat kidney tumour cells were transplanted into either Wistar or Lewis recipients which mimic a well and poorly matched combination to assess the effects of MHC matching on transplanted tumour cells. Experimental groups included controls with no immunosuppression and animals immunosuppressed with cyclosporine. The latter group was further divided into a continuous treatment group which received four weeks of immunosuppression and a treatment withdrawal group where immunosuppression was stopped after two weeks to assess the effects of rejection on tumour growth. RESULTS: All the tumour cells were rejected in the control animals that received no immunosuppression, within 2 weeks among well-matched combination and within one week in the poorly matched combination (p 0.001). The transplanted tumour cells continued to grow in both well-matched and poorly matched groups who were treated with cyclosporine, but growth was significantly faster in the well-matched combination (p 0.033). After treatment withdrawal the tumour cells were rejected in all the animals of the poorly matched group compared to 50% in well matched animals within the four-week study period (p 0.039). CONCLUSION: In the absence of immunosuppression the hosts reject the transplanted tumour cells, and the anti-tumour response is stronger when there is a greater mismatch in MHC with the recipient. In the presence of cyclosporine immunosuppression the tumour continues to grow, however, after withdrawal of the immunosuppression, tumour clearance is quicker in the poorly matched background. This data supports the idea of expansion of the donor pool by using kidneys after ex vivo resection of small renal tumours and that these organs should be transplanted into a less well-matched HLA recipient. We hypothesise that should a tumour recurrence occur a poorly matched recipient could clear the tumour through withdrawal of immunosuppression.

Development of an ex vivo technique to achieve reanimation of hearts sourced from a porcine donation after circulatory death model.

BACKGROUND: This study reports on the development of a novel method for achieving ex vivo reanimation of hearts from a porcine donation after circulatory death (DCD) model without the use of donor pretreatment. METHODS: Porcine hearts (n = 23) were procured 10-29 min after confirmation of asystole. All hearts underwent initial flush with AQIX RS-I solution (London, UK). A 2-h preservation period followed: group 1 hearts (n1-n11) were preserved using static cold storage, group 2 hearts (n12-n17) were preserved using oxygenated, hypothermic machine perfusion (MP), and group 3 hearts (n18-n23) were subjected to retrograde oxygen persufflation. Reperfusion was performed on a Langendorff modification of a Model 33 Functional Circulation circuit. In hearts n16-n23, a dialysis circuit was incorporated into the circuit to facilitate removal of metabolites. The experimental protocol was allowed to follow an evolutionary course, with the aim of achieving greater success with reanimation. RESULTS: In group 1 (static cold storage), 7 of the 11 hearts (63.6%) achieved reanimation on the ex vivo circuit. Two of the six hearts (33.3%) in group 2 (MP) were successfully reanimated. All the six hearts (100%) in group 3 (persufflation) were successfully reanimated. The period of sustained reanimation increased when dialysis was incorporated into the circuit with a maximum of 300 min. CONCLUSIONS: Porcine DCD hearts after 29 min of warm ischemia can be reanimated using the method described. A mechanism of reoxygenation (oxygenated MP or coronary sinus oxygen persufflation) during preservation appears mandatory for hearts from DCDs. Persufflation was associated with a higher probability of successful reanimation. Dialysis in the warm phase was useful in removing metabolites that could interfere with reanimation. The results demonstrate the potential of DCDs to counter the decline affecting heart transplantation.

Extracorporeal membrane oxygenation for resuscitation of deceased cardiac donor livers for hepatocyte isolation.

BACKGROUND: Deceased cardiac donors (DCDs) have become a useful source of organs for liver transplantation; nevertheless, there are concerns about the longevity of these grafts. The aim of this study was to evaluate the use of extracorporeal membrane oxygenation (ECMO) to resuscitate DCD porcine livers as a preclinical model using hepatocyte isolation and viability as a marker to assess whole-graft preservation. MATERIALS AND METHODS: We randomized Landrace pigs into three groups after cardiac death and 30 min of warm ischemia: group 1, peritoneal cooling with intravascular cooling for 2 h; group 2, ECMO for 2 h; and group 3, control (conventional intravascular cooling and retrieval). We then reperfused group 1 and 2 livers for 2 h on an ex vivo reperfusion circuit and isolated hepatocytes. RESULTS: After reperfusion, hepatocyte viability was significantly improved in the ECMO group compared to the cooling groups, as measured by trypan blue, methylthiazolyldiphenyl-tetrazolium bromide, and seeding efficiency. Glycogen and reduced glutathione content were significantly used in the ECMO group both before and after reperfusion compared with group 2. The adenosine diphosphate:adenosine triphosphate ratio showed an improved trend (lower) in the ECMO group compared with the cooling group but did not reach statistical significance either before or after reperfusion. CONCLUSIONS: This preclinical study suggests that ECMO is a viable technique for liver preservation that gives an improved yield of hepatocytes when isolated from a DCD liver, suggesting improved liver preservation.

Analysis of peripheral blood T-cell subsets in active thyroid-associated ophthalmopathy: absence of effect of octreotide-LAR on T-cell subsets in patients with thyroid-associated ophthalmopathy.

Thyroid-associated ophthalmopathy (TAO) is thought to be a T-cell-mediated autoimmune disorder. We sought to characterize abnormalities in the peripheral blood T-cell subsets in patients with TAO, and examine whether the long-acting somatostatin analogue, octreotide-LAR, treatment affects these cells. We analyzed peripheral blood T-cell subsets by flow cytometry in 26 euthyroid patients with moderately severe active TAO and 24 controls. Twenty-five of the patients with TAO were enrolled in a randomized trial to receive either 30 mg of octreotide-LAR (n = 11) or placebo (n = 14) every 4 weeks for 16 weeks; all 25 patients subsequently received octreotide-LAR 30 mg every 4 weeks from week 16 to 32. T-cell subsets were analysed at baseline, week 16, and week 32. At baseline, the relative percentage of CD4+ helper T-cells (p = 0.0003) and the CD4+/CD8+ ratio (p = 0.008) were significantly higher in patients with TAO compared to controls. Patients with TAO had higher naïve active T cells (CD45RA+, CD45RA+ CD4+) and lower memory T cells (CD45RO+, CD45RO+ CD4+) than controls. At weeks 16 and 32, there were no significant differences in any T-cell subsets between the octreotide-LAR-treated and placebo groups. These results support a role of T cell in the pathogenesis of TAO, and show that octreotide-LAR has no effect on T-cell subsets during 32-weeks of treatment.

Transplantation from non heart beating donors in Newcastle upon Tyne.

Donor shortage has led transplant surgeons to reevaluate the concept of non heart beating donation. Organs from such donors are exposed to anoxia prior to harvesting and a portion of them will consequently present with delayed graft function. There is a need for dependable viability testing of organs from less than ideal NHBD donors and machine perfusion of kidneys provides such a tool. Our experience with own design machine perfusion device, studied parameters, perfusion solutions and outcomes is presented. Emphasis is placed on the incomparability of results obtained from different perfusion systems and the need to establish local criteria of kidney viability.