C Ceresa

A randomized trial of normothermic preservation in liver transplantation

Liver transplantation is a highly successful treatment, but is severely limited by the shortage in donor organs. However, many potential donor organs cannot be used; this is because sub-optimal livers do not tolerate conventional cold storage and there is no reliable way to assess organ viability preoperatively. Normothermic machine perfusion maintains the liver in a physiological state, avoids cooling and allows recovery and functional testing. Here we show that, in a randomized trial with 220 liver transplantations, compared to conventional static cold storage, normothermic preservation is associated with a 50% lower level of graft injury, measured by hepatocellular enzyme release, despite a 50% lower rate of organ discard and a 54% longer mean preservation time. There was no significant difference in bile duct complications, graft survival or survival of the patient. If translated to clinical practice, these results would have a major impact on liver transplant outcomes and waiting list mortality.Normothermic machine perfusion of the liver improved early graft function, demonstrated by reduced peak serum aspartate transaminase levels and early allograft dysfunction rates, and improved organ utilization and preservation times, although no differences were seen in graft or patient survival.

Outcomes following renal transplantation in older people: a retrospective cohort study

BackgroundThe mean age of renal transplant recipients is rising, with age no longer considered a contraindication. Outcomes in older patients have not, however, been fully defined. The aim of our study is to evaluate outcomes in older people following renal transplantation at a Scottish regional transplant unit.MethodsAll renal transplants from January 2001 to December 2010 were analysed (n = 762). Outcomes following renal transplantation in people over 65 years old were compared to those in younger patients. Outcome measures were: delayed graft function (DGF), primary non-function (PNF), biopsy proven acute rejection (BPAR), serum creatinine at 1 year and graft and recipient survival. Lengths of initial hospital stay and re-admission rates were also assessed. Student’s T-Test was used to analyse continuous variables, Pearson’s Chi-Squared test for categorical variables and the Kaplan-Meier estimator for survival analysis.ResultsOlder recipients received proportionately more kidneys from older donors (27.1% vs. 6.3%; p  <  0.001). Such kidneys were more likely to have DGF (40.7% vs. 16.9%; p < 0.001). Graft loss at 1 year was higher in kidneys from older donors (15.3% vs. 7.6%; p = 0.04). There was no significant difference in patient survival at 1 year based on the age of the donor kidney. Recipient age did not affect DGF (16.9% vs. 18.5%; p = 0.77) or graft loss at 1 year (11.9% vs. 7.8%; p = 0.28). Older recipients were, however, more likely to die in the first year post transplant (6.8% vs. 2.1%; p = 0.03). BPAR was less common in older patients (6.8% vs. 22%; p < 0.01). Older recipients were more likely to be readmitted to hospital (31.8% vs. 10.9%; p < 0.001).ConclusionsOlder patients experience good outcomes following renal transplantation and donor or recipient age alone should not preclude this treatment. An awareness of this in clinicians managing older patients is important since the prevalence of End Stage Renal Disease is increasing in this age group.

The case for normothermic machine perfusion in liver transplantation.

In recent years, there has been growing interest in normothermic machine perfusion (NMP) as a preservation method in liver transplantation. In most countries, because of a donor organ shortage, an unacceptable number of patients die while awaiting transplantation. In an attempt to increase the number of donor organs available, transplant teams are implanting a greater number of high‐risk livers, including those from donation after circulatory death, older donors, and donors with steatosis. NMP maintains the liver ex vivo on a circuit by providing oxygen and nutrition at 37°C. This permits extended preservation times, the ability to perform liver viability assessment, and the potential for liver‐directed therapeutic interventions during preservation. It is hoped that this technology may facilitate the enhanced preservation of marginal livers with improved posttransplant outcomes by reducing ischemia/reperfusion injury. Clinical trials have demonstrated its short‐term superiority over cold storage in terms of early biochemical liver function, and it is anticipated that it may result in increased organ utilization, helping to reduce the number of wait‐list deaths. However, further studies are required to demonstrate longer‐term efficacy and the impact on biliary complications as well as further knowledge to exploit and maximize the potential of this exciting new technology. Liver Transplantation 24 269–275 2018 AASLD.

Cold storage or normothermic perfusion for liver transplantation: probable application and indications.

Purpose of review Preservation of the liver via normothermic machine perfusion (NMP) is rapidly becoming an area of great academic and clinical interest. This review focuses on the benefits and limitations of NMP and where the role for static cold storage may lie. Recent findings Clinical studies have recently been published reporting the use of NMP in liver preservation for transplantation. They have described the technology to be well tolerated and feasible with potentially improved posttransplant outcomes. NMP facilitates extended preservation times as well as the potential to increase organ utilization through viability assessment and regeneration. However, this technology is considerably more costly than cold storage and carries significant logistical challenges. Cold storage remains the gold standard preservation for standard criteria livers with good long-term patient and graft survival. Summary NMP is an exciting new technological advancement in liver preservation, which is likely to have a positive impact in liver transplantation. However, randomized controlled trials are required to justify its inclusion into standard practice and provide evidence to support its efficacy.

Normothermic Machine Preservation of the Liver: State of the Art.

Purpose of ReviewThis review aims to introduce the concept of normothermic machine perfusion (NMP) and its role in liver transplantation. By discussing results from recent clinical studies and highlighting the potential opportunities provided by this technology, we aim to provide a greater insight into NMP and the role it can play to enhance liver transplantation.Recent FindingsNMP has recently been shown to be both safe and feasible in liver transplantation and has also demonstrated its superiority to traditional cold storage in terms of early biochemical liver function. Through the ability to perform a viability assessment during preservation and extend preservation times, it is likely that an increase in organ utilisation will follow. NMP may facilitate the enhanced preservation with improved outcomes from donors after cardiac death and steatotic livers. Furthermore, it provides the exciting potential for liver-directed therapeutic interventions.SummaryEvidence to date suggests that NMP facilitates the enhanced preservation of liver grafts with improved early post-transplant outcomes. The key role for this technology is to increase the number and quality of liver grafts available for transplantation and to reduce waiting list deaths.

Outcomes of Renal Transplantation in Patients With Major Lower Limb Amputation

INTRODUCTION The impact of severe peripheral vascular disease on graft survival in patients undergoing renal transplantation is poorly defined. The aim of our study is to establish outcomes in renal transplant recipients who have severe peripheral vascular disease necessitating major lower limb amputation. METHODS Data for patients undergoing renal transplantation from January 2001-December 2010 was extracted from a regional transplantation database. Patients undergoing lower limb amputation pre- and post-transplantation were identified and outcome measures including delayed graft function, biopsy-proven acute rejection, serum creatinine level at 1 year, and graft loss and recipient survival at 1 year and long-term were compared with patients who did not undergo amputation. Student t and Pearsons chi-squared tests were used to compare patients with and without amputation and Kaplan-Meier curves were used for survival analysis. A P value < .05 is considered statistically significant. RESULTS A total of 762 patients underwent renal transplantation. Four (0.5%) patients had an amputation before transplantation and 16 (2.1%) underwent amputation after transplantation. Serum creatinine levels at 1 year were significantly higher in patients who had amputation after transplantation (308.5 ± 60.8 μmol/l vs 177.6 ± 6.4 μmol/l; P = .03). During longer follow-up (mean: 2053.1 ± 58.3 days), patients who underwent amputation after transplantation had a higher rate of graft loss (P < .01) and higher death rate (P < .01). CONCLUSION The requirement for amputation after renal transplantation is associated with poor long-term graft and patient survival and higher serum creatinine levels at 1 year. Patients at increased risk of severe peripheral vascular disease should be identified and measures taken to reduce the long-term risk.

Studying non-alcoholic fatty liver disease: the ins and outs of in vivo, ex vivo and in vitro human models.

Abstract The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing. Determining the pathogenesis and pathophysiology of human NAFLD will allow for evidence-based prevention strategies, and more targeted mechanistic investigations. Various in vivo, ex situ and in vitro models may be utilised to study NAFLD; but all come with their own specific caveats. Here, we review the human-based models and discuss their advantages and limitations in regards to studying the development and progression of NAFLD. Overall, in vivo whole-body human studies are advantageous in that they allow for investigation within the physiological setting, however, limited accessibility to the liver makes direct investigations challenging. Non-invasive imaging techniques are able to somewhat overcome this challenge, whilst the use of stable-isotope tracers enables mechanistic insight to be obtained. Recent technological advances (i.e. normothermic machine perfusion) have opened new opportunities to investigate whole-organ metabolism, thus ex situ livers can be investigated directly. Therefore, investigations that cannot be performed in vivo in humans have the potential to be undertaken. In vitro models offer the ability to perform investigations at a cellular level, aiding in elucidating the molecular mechanisms of NAFLD. However, a number of current models do not closely resemble the human condition and work is ongoing to optimise culturing parameters in order to recapitulate this. In summary, no single model currently provides insight into the development, pathophysiology and progression across the NAFLD spectrum, each experimental model has limitations, which need to be taken into consideration to ensure appropriate conclusions and extrapolation of findings are made.