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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., Author(s): David Nasralla [sup.1] , Constantin C. Coussios [sup.2] , Hynek Mergental [sup.3] , M. Zeeshan Akhtar [sup.1] [sup.4] , Andrew J. Butler [sup.5] , Carlo D. L. Ceresa [sup.1] [...]

Background: The 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. Methods: All 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. Results: Older 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). Conclusions: Older 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. [ABSTRACT FROM AUTHOR]

Using 13 C 6 glucose labeling coupled to gas chromatography-mass spectrometry and 2D 1 H- 13 C heteronuclear single quantum coherence NMR spectroscopy, we have obtained a comparative high-resolution map of glucose fate underpinning β cell function. In both mouse and human islets, the contribution of glucose to the tricarboxylic acid (TCA) cycle is similar. Pyruvate fueling of the TCA cycle is primarily mediated by the activity of pyruvate dehydrogenase, with lower flux through pyruvate carboxylase. While the conversion of pyruvate to lactate by lactate dehydrogenase (LDH) can be detected in islets of both species, lactate accumulation is 6-fold higher in human islets. Human islets express LDH, with low-moderate LDHA expression and β cell-specific LDHB expression. LDHB inhibition amplifies LDHA-dependent lactate generation in mouse and human β cells and increases basal insulin release. Lastly, cis-instrument Mendelian randomization shows that low LDHB expression levels correlate with elevated fasting insulin in humans. Thus, LDHB limits lactate generation in β cells to maintain appropriate insulin release., Competing Interests: Declaration of interests G.A.R. has received grant funding from, and is a consultant for, Sun Pharmaceuticals Industries Ltd. D.J.H. receives licensing revenue from Celtarys Research for provision of chemical probes. D.J.H. has filed patents related to type 1 diabetes and type 2 diabetes therapy, unrelated to the present study., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Normothermic ex situ liver perfusion is increasingly used to assess donor livers, but there remains a paucity of evidence regarding criteria upon which to base a viability assessment or criteria predicting early allograft function., Methods: Perfusate variables from livers undergoing normothermic ex situ liver perfusion were analyzed to see which best predicted the Model for Early Allograft Function score., Results: One hundred fifty-four of 203 perfused livers were transplanted following our previously defined criteria. These comprised 84/123 donation after circulatory death livers and 70/80 donation after brain death livers. Multivariable analysis suggested that 2-h alanine transaminase, 2-h lactate, 11 to 29 mmol supplementary bicarbonate in the first 4 h, and peak bile pH were associated with early allograft function as defined by the Model for Early Allograft Function score. Nonanastomotic biliary strictures occurred in 11% of transplants, predominantly affected first- and second-order ducts, despite selection based on bile glucose and pH., Conclusions: This work confirms the importance of perfusate alanine transaminase and lactate at 2-h, as well as the amount of supplementary bicarbonate required to keep the perfusate pH > 7.2, in the assessment of livers undergoing perfusion. It cautions against the use of lactate as a sole indicator of viability and also suggests a role for cholangiocyte function markers in predicting early allograft function., Competing Interests: C.J.E.W. participated in advisory boards with Nefro Health and Jazz Pharmaceuticals and has received speaker fees from OrganOx. A.J.B. is coholder of a patent on the circuit used in the OrganOx metra. C.D.L.C. has received income from OrganOx Ltd for teaching and training and for carrying out normothermic preservations after normal working hours. The other authors declare no conflicts of interest., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: During pancreatic resections assessing tumour boundaries and identifying the ideal resection margins can be challenging due to the associated pancreatic gland inflammation and texture. This is particularly true in the context of minimally invasive surgery, where there is a very limited or absent tactile feedback. Indocyanine green (ICG) fluorescence imaging can assist surgeons by simply providing valuable real-time intraoperative information at low cost with minimal side effects. This meta-analysis summarises the available evidence on the use of near-infrared fluorescence imaging with ICG for the intraoperative visualization of pancreatic tumours (PROSPERO ID: CRD42021247203)., Methods: MEDLINE, Embase, and Web Of Science electronic databases were searched to identify manuscripts where ICG was intravenously administered prior to or during pancreatic surgery and reporting the prevalence of pancreatic lesions visualised through fluorescence imaging., Results: Six studies with 7 series' reporting data on 64 pancreatic lesions were included in the analysis. MINOR scores ranged from 6 to 10, with a median of 8. The most frequent indications were pancreatic adenocarcinoma and neuroendocrine tumours. In most cases (67.2%) ICG was administered during surgery. ICG fluorescence identified 48/64 lesions (75%) with 81.3% accuracy, 0.788 (95%CI 0.361-0.961) sensitivity, 1 (95%CI 0.072-1) specificity and positive predictive value of 0.982 (95%CI 0.532-1). In line with the literature, ICG fluorescence identified 5/6 (83.3%) of pancreatic lesions during robotic pancreatic resections performed at our Institution., Conclusion: This meta-analysis is the first summarising the results of ICG immunofluorescence in detecting pancreatic tumours during surgery, showing good accuracy. Additional research is needed to define optimal ICG administration strategies and fluorescence intensity cut-offs., (Copyright © 2022 International Hepato-Pancreato-Biliary Association Inc. Published by Elsevier Ltd. All rights reserved.)

The study compares urine recirculation (URC) to urine replacement (UR) with Ringer's lactate in a porcine normothermic kidney machine perfusion (NMP) model using a preclinical prototype device., Methods: Kidney pairs were recovered uninjured (as live-donor nephrectomy) and perfused consecutively. Pig kidneys (n = 10) were allocated to either NMP with URC (n = 5) or NMP with volume replacement (n = 5). Cold ischemia time was either 2 or 27 hours for the first or second perfusion (URC or UR) of a kidney pair. An autologous blood-based perfusate, leukocyte-filtered, was used and NMP performed up to 24 hours. Perfusion parameters, biochemistry/metabolic parameters were monitored and samples collected., Results: Physiological mean arterial pressures and flows were achieved in both groups but were sustainable only with URC. Significantly higher arterial flow was observed with URC (326.7 ± 1.8 versus 242.5 ± 14.3 mL/min, P = 0.001). Perfusate sodium levels were lower with URC, 129.6 ± 0.7 versus 170.3±2.7 mmol/L, P < 0.001). Stable physiological pH levels were only observed with URC. Perfusate lactate levels were lower with URC (2.2 ± 0.1 versus 7.2 ± 0.5 mmol/L, P < 0.001). Furthermore, the hourly rate of urine output was lower with URC and closer to physiological levels (150 versus 548 mL/h, P = 0.008). Normothermic kidney perfusion with URC was associated with longer achievable durations of perfusion: the objective in all experiments was a 24-hour perfusion, but this was not achieved in every case. The mean perfusions were 17.3 ± 9.2 hours with URC versus 5.3 ± 1.3 hours NMP with UR; P = 0.02. There appeared to be no differences in baseline tubular condition with and without URC., Conclusions: URC facilitates long-term kidney NMP in a porcine model. Perfusate homeostasis and stability of renal arterial flow throughout the perfusion period was only achievable with URC, independent of cold ischemia time duration., Competing Interests: This research was supported by the Oxford Centre for Drug Delivery Devices under Programme Grant EP/L024012/1 from the UK’s Engineering and Physical Sciences Research Council., (Copyright © 2020 The Author(s). Transplantation Direct. Published by Wolters Kluwer Health, Inc.)

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.