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Background: Normothermic machine perfusion (NMP) has been proposed to preserve liver grafts in a less pro‐inflammatory environment. However, the effect of NMP on liver inflammation remains unclear. Therefore, we aimed at characterizing the inflammatory response during continuous NMP with a comprehensive investigation of cytokine release during perfusion. Methods: Ten porcine livers underwent either 24 h NMP or whole blood‐based NMP (WB‐NMP) immediately after procurement. WB‐NMP was used as a positive control to mimic early post‐reperfusion inflammation. High mobility group box‐1 (HMGB1), interleukin 1‐beta (IL‐1beta), tumor necrosis factor‐alpha (TNFalpha), interleukin 6 (IL‐6), 8 (IL‐8), and 10 (IL‐10), transforming growth factor‐beta (TGFbeta), aspartate transferase (AST), and hyaluronic acid were measured in the perfusate. The area under the curve (AUC) of their perfusate concentration was compared between groups. Median (IQR) is given. Results: The AUC of HMGB1 and IL‐1beta was similar between groups. Compared to WB‐NMP, NMP inhibited the release of TNFalpha [NMP: 20275 (18402–32 152), WB‐NMP: 242100 (203511–244 238); p = 0.01], IL‐6 [NMP: 1206 (338.9–1686), WB‐NMP: 8444 (7359–10 087); p = 0.03], and IL‐8 [NMP: 1635 (106.90–2130), WB‐NMP: 3951 (3090–4116); p = 0.008]. The release of TGFbeta remained unchanged but IL‐10 release was lower in NMP [1612 (1313–1916), WB‐NMP: 5591 (4312–6421); p = 0.01]. The ratios TGFbeta:TNFalpha and IL‐10:TNFalpha were significantly higher in the NMP than in the WB‐NMP group. Importantly, the AUC of AST was significantly lower during NMP [1960 (1950–2893)] than WB‐NMP [6812 (6370–7916); p = 0.02]. Conclusions: Continuous NMP leads to the release of detectable levels of cytokines with a slow, linear increase over time and a shift toward anti‐inflammatory signaling. [ABSTRACT FROM AUTHOR]

Background: Liver donation after cardiac death (DCD) makes up a small percentage of the organs used in transplantation and poses a higher risk of graft loss compared to donation after brain death (DBD); this is a result of ischemia reperfusion for which the exact injury mechanisms are currently not fully understood. However, reperfusion injury has been shown to lead to necrosis as well as apoptosis through oxidative stress and mitochondrial dysfunction. In this work, we propose that use of the pro-survival, anti-apoptotic CEPT cocktail in post-ischemia normothermic machine perfusion (NMP) may improve recovery in rat livers subjected to extended durations of warm ischemia. Materials and Methods: Livers procured from male Lewis rats were subjected to 90 min of warm ischemia, followed by 6 h of NMP where they were treated either with the survival-enhancing anti-apoptotic cocktail (CEPT), the vehicle (DMSO) or the base media with no additives. Results: The CEPT-treated group exhibited lower expression of hepatic injury biomarkers, and improvement in a range of hepatocellular symptoms associated with the hepatic parenchyma, biliary epithelium and the sinusoidal endothelium, including recovery of bile secretion and lowered vascular resistance. Conclusions: This study's findings suggest apoptosis plays a more significant role in ischemia-reperfusion injury than previously understood, and provide useful insight for further investigation of the specific underlying mechanisms and development of novel treatment methods.

Background: Recently, the method of machine perfusion of a liver transplant, which has been gaining popularity, justifies the hopes placed on it. At the same time, the existence of many perfusion schemes confirms the need to find the optimal one. The purpose of this study was to experimentally develop a perfusion scheme for long-term preservation of the liver outside the body by perfusion with normothermic oxygenated blood. Materials and methods: To create a perfusion device, we used a roller blood pump console, a standard pediatric oxygenator, venous and arterial filters, polyvinyl chloride and silicone lines, and a constant-flow-to-pulsating (external pulsator) converter of our own design. In the perfusion scheme after the roller pump, the blood flow was divided into two streams. The first was sent to the oxygenator. Then, having passed the pulsator, the flow was fed through the aortic stump into the hepatic artery. The second flow was directed to the upper soft-walled tank. As an experimental model, 5 pigs weighing up to 20 kg were used. Under general endotracheal anesthesia under conditions of thoraco-laparotomy, the liver was explanted along with a section of the caudal vena cava and aorta. Injection cannulas were inserted into the aorta and portal vein, and a draining cannula was inserted into the distal end of the vena cava. The cannulas were connected to the perfusion machine and perfusion of the organ was started. Sensors for monitoring blood flow volume, pressure, temperature, and blood oxygen saturation were located at different parts of the perfusion scheme. Results and discussion: All experiments were carried out for 12 hours. The temperature of the perfusate was maintained within the range up to 37°C; volumetric blood flow in the portal vein was 450-500 ml/min; pressure was maintained within 12-24 mm Hg; the pulse rate in the arterial line did not exceed 100 beats/world; volumetric blood flow in the hepatic artery averaged 80-120 ml/min; the average pressure was maintained within 70 mm Hg. Dosing clamps located on the lines provided the opportunity to optimally redistribute the perfusate flows. So in the caudal vena cava, the pressure was maintained with in the physiological norm. At the same time, the required level of perfusate for gravitational injection into the portal vein was stabilized in the soft-walled reservoir. Conclusion: The developed scheme for machine perfusion liver preservation allows stabilizing two blood (arterial and venous) flows of different characteristics during a prolonged experiment. In parallel with the liver, the kidney, which is adequately perfused in the general blood flow, can function as a controller of hemohydrobalance, a stabilizer of acid-base balance, and an eliminator of metabolic wastes. [ABSTRACT FROM AUTHOR]

Purpose: This paper presents an assessment of a low-cost organ perfusion machine designed for use in research settings. The machine is modular and versatile in nature, built on a robotic operating system (ROS2) pipeline allowing for the addition of specific sensors for different research applications. Here we present the system and the development stages to achieve viability of the perfused organ. Methods: The machine's perfusion efficacy was assessed by monitoring the distribution of perfusate in livers using methylene blue dye. Functionality was evaluated by measuring bile production after 90 min of normothermic perfusion, while viability was examined using aspartate transaminase assays to monitor cell damage throughout the perfusion. Additionally, the output of the pressure, flow, temperature, and oxygen sensors was monitored and recorded to track the health of the organ during perfusion and assess the system's capability of maintaining the quality of data over time. Results: The results show the system is capable of successfully perfusing porcine livers for up to three hours. Functionality and viability assessments show no deterioration of liver cells once normothermic perfusion had occurred and bile production was within normal limits of approximately 26 ml in 90 min showing viability. Conclusion: The developed low-cost perfusion system presented here has been shown to keep porcine livers viable and functional ex vivo. Additionally, the system is capable of easily incorporating several sensors into its framework and simultaneously monitor and record them during perfusion. The work promotes further exploration of the system in different research domains. [ABSTRACT FROM AUTHOR]

Organ transplantation remains the only treatment option for patients with end-stage organ failure. The last decade has seen a flurry of activity in improving organ preservation technologies, which promise to increase utilization in a dramatic fashion. They also bring the promise of extending the preservation duration significantly, which opens the doors to sharing organs across local and international boundaries and transforms the field. In this work, we review the recent literature on machine perfusion of livers across various protocols in development and clinical use, in the context of extending the preservation duration. We then review the next generation of technologies that have the potential to further extend the limits and open the door to banking organs, including supercooling, partial freezing, and nanowarming, and outline the opportunities arising in the field for researchers in the short and long term.

Pediatric liver tumors with portal vein obstruction are often candidates for liver transplantation. However, lifelong use of immunosuppressants and invasiveness to healthy donors in the case of living-donor liver transplantation is inevitable. Moreover, when lung metastasis is involved, the lung recurrence rate after liver transplantation is still high. Therefore, transplantation should be avoided as much as possible. In cases of tumors in the right lobe of the liver, complete resection of the portal vein trunk may be possible by creating a Rex bypass, but with the original method, end-to-side anastomosis to the umbilical portal vein is difficult in small children. We report a case of a 2-year-old girl with hepatoblastoma in whom a Rex shunt was created by end-to-end anastomosing the recanalized umbilical vein to the portal vein stump with interposing a vein graft, and the right lobe was successfully resected along with the tumor.

Background: Normothermic regional perfusion (NRP) and machine perfusion (MP) are variously used in many European centers to improve the outcomes after liver transplantation from donation after circulatory death (DCD). In Italy, a combination of NRP and subsequent MP has been used since the start of the activity. While NRP is mandatory for every DCD recovery, the subsequent use of MP is left to each center. Methods: We have designed a national survey to investigate practices and policies of these techniques. The questionnaire included 46 questions and was distributed to all the 21 Italian centers using an online form between June and July 2021. Results: The overall response rate was 100%. A local NRP program for controlled Maastricht type 3 DCD was active in 11/21 (52.4%) centers. Organization and availability of personnel were perceived as the main difficulties in starting such a program. Between 2015 and 2020, 119 DCD livers were transplanted, with an overall utilization rate of 69.2%. Pump flow and gross aspect were considered the most reliable parameters in liver selection during NRP. Eight (72.7%) centers adopted subsequent hypothermic MP, 1 (9.1%) center normothermic MP, and the remaining 2 (18.2%) used both MP types. Conclusion: This first snapshot survey shows that NRP with subsequent MP is the most used protocol in Italy for DCD livers, although some heterogeneity exists in the type and purpose of MP between centers. Overall, this policy ensures a high utilization rate, considering the high risk of the DCD donor population in Italy. [ABSTRACT FROM AUTHOR]

Although short-term machine perfusion (-24 h) allows for resuscitation and viability assessment of high-risk donor livers, the donor organ shortage might be further remedied by long-term perfusion machines. Extended preservation of injured donor livers may allow reconditioning, repairing, and regeneration. This review summarizes the necessary requirements and challenges for long-term liver machine preservation, which requires integrating multiple core physiological functions to mimic the physiological environment inside the body. A pump simulates the heart in the perfusion system, including automatically controlled adjustment of flow and pressure settings. Oxygenation and ventilation are required to account for the absence of the lungs combined with continuous blood gas analysis. To avoid pressure necrosis and achieve heterogenic tissue perfusion during preservation, diaphragm movement should be simulated. An artificial kidney is required to remove waste products and control the perfusion solution's composition. The perfusate requires an oxygen carrier, but will also be challenged by coagulation and activation of the immune system. The role of the pancreas can be mimicked through closed-loop control of glucose concentrations by automatic injection of insulin or glucagon. Nutrients and bile salts, generally transported from the intestine to the liver, have to be supplemented when preserving livers long term. Especially for long-term perfusion, the container should allow maintenance of sterility. In summary, the main challenge to develop a long-term perfusion machine is to maintain the liver's homeostasis in a sterile, carefully controlled environment. Long-term machine preservation of human livers may allow organ regeneration and repair, thereby ultimately solving the shortage of donor livers. [ABSTRACT FROM AUTHOR]

BACKGROUND: The cold ischemia –reperfusion injury may lead to microcirculatory disturbances, hepatocellular swelling, inflammation, and organ dysfunction. Nicorandil is an anti-ischemic, ATP-sensitive potassium (KATP) channel opener drug and has proved its effectiveness against hepatic Ischemia/Reperfusion (I/R) injury. OBJECTIVE: This study aimed to investigate the effect of Nicorandil on mitochondrial apoptosis, oxidative stress, inflammation, histopathological changes, and cold ischemic tolerance of the liver in an ex vivo experimental isolated-organ-perfusion model. METHODS: We used an ex vivo isolated rat liver perfusion system for this study. The grafts were retrieved from male Wistar rats (n = 5 in each), preserved in cold storage (CS) for 2 or 4 hours (group 1, 2), or perfused for 2 or 4 hours (group 3, 4) immediately after removal with Krebs Henseleit Buffer (KHB) solution or Nicorandil containing KHB solution under subnormothermic (22–25°C) conditions (group 5, 6). After 15 minutes incubation at room temperature, the livers were reperfused with acellular, oxygenated solution under normothermic condition for 60 minutes. RESULTS: In the Nicorandil perfused groups, significantly decreased liver enzymes, GLDH, TNF-alpha, and IL-1ß were measured from the perfusate. Antioxidant enzymactivity was higher in the perfused groups. Histopathological examination showed ameliorated tissue deterioration, preserved parenchymal structure, decreased apoptosis, and increased Bcl-2 activity in the Nicorandil perfused groups. CONCLUSIONS: Perfusion with Nicorandil containing KHB solution may increase cold ischemic tolerance of the liver via mitochondrial protection which can be a potential therapeutic target to improve graft survival during transplantation. [ABSTRACT FROM AUTHOR]

The advantages of oxygenated perfusion are continuing to be demonstrated by many groups focused on improving the efficacy of tissue preservation for transplant, bioreactors for studies of basic tissue physiology, and closed-loop resuscitation. This work presents a novel and portable device that supplies oxygenated and pulsatile perfusion, both of which are regulated by a single pump-oxygenator component comprised of silicone tubes that are cyclically inflated/deflated with compressed oxygen. In this study, pump variables (oxygen supply pressure and length of a silicone tube) were evaluated against hydraulic elements that mimicked the vascular resistance of kidneys, livers, and hearts. The perfusion pressures, flow rates, and oxygenation rates produced by the device were characterized for all configurations of pump variables, and the pulse rates were tuned to improve performance. The device supplied perfusion pressures ranging from 3.5 to 109 mmHg, flow rates ranging from 1.4 to 71.8 mL min−1, and oxygenation rates up to 316.6 µmol min−1. From those results, it was determined that the device was capable of achieving perfusion parameters used in previous kidney, liver, and heart preservation studies. Ultimately, this research demonstrated the efficacy of a novel device that is designed to supply oxygenated perfusion across a range of applications. [ABSTRACT FROM AUTHOR]

Background: Liver donation after cardiac death (DCD) makes up a small percentage of the organs used in transplantation and poses a higher risk of graft loss compared to donation after brain death (DBD); this is a result of ischemia reperfusion for which the exact injury mechanisms are currently not fully understood. However, reperfusion injury has been shown to lead to necrosis as well as apoptosis through oxidative stress and mitochondrial dysfunction. In this work, we propose that use of the pro-survival, anti-apoptotic CEPT cocktail in post-ischemia normothermic machine perfusion (NMP) may improve recovery in rat livers subjected to extended durations of warm ischemia., Materials and Methods: Livers procured from male Lewis rats were subjected to 90 min of warm ischemia, followed by 6 h of NMP where they were treated either with the survival-enhancing anti-apoptotic cocktail (CEPT), the vehicle (DMSO) or the base media with no additives., Results: The CEPT-treated group exhibited lower expression of hepatic injury biomarkers, and improvement in a range of hepatocellular symptoms associated with the hepatic parenchyma, biliary epithelium and the sinusoidal endothelium, including recovery of bile secretion and lowered vascular resistance., Conclusions: This study's findings suggest apoptosis plays a more significant role in ischemia-reperfusion injury than previously understood, and provide useful insight for further investigation of the specific underlying mechanisms and development of novel treatment methods., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Korkut Uygun reports financial support was provided by 10.13039/100005294Massachusetts General Hospital. Korkut Uygun reports a relationship with 10.13039/100000002National Institutes of Health that includes: funding grants. Some authors declare competing interests. Drs. Uygun, Tessier, Yeh and Toner have patent applications relevant to this study. Drs. Uygun, Tessier and Toner have a financial interest in and serve on the Scientific Advisory Board for Sylvatica Biotech Inc., a company focused on developing high subzero organ preservation technology. Competing interests for MGH investigators are managed by the MGH and MGB in accordance with their conflict-of-interest policies. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Since the advent of University of Wisconsin preservation solution in the 1980s, clinicians have learned to work within its confines. While affording improved outcomes, considerable limitations still exist and contribute to the large number of livers that go unused each year, often for fear they may never work. The last 10 years have seen the widespread availability of new perfusion modalities which provide an opportunity for assessing organ viability and prolonged organ storage. This review will discuss the role of in situ normothermic regional perfusion for livers donated after circulatory death. It will also describe the different modalities of ex situ perfusion, both normothermic and hypothermic, and discuss how they are thought to work and the opportunities afforded by them. [Display omitted] [ABSTRACT FROM AUTHOR]

Liver transplantation is the only effective treatment for end-stage liver disease. Currently, the shortage of high-quality donors has led to the exploration of the use of marginal organs. However, several factors limit the in vitro long-term preservation and long-distance transport of livers, which can also lead to ischemia-reperfusion injuries, resulting in poor prognosis. Therefore, an efficient and convenient strategy to improve this situation is urgently required. Normothermic machine perfusion (NMP) is expected to improve the liver environment in vitro and provide better evaluation indices for organ repair mechanisms. Mesenchymal stem cells (MSCs) can repair damaged hepatocytes or exert their protective effects via paracrine mechanisms, such as the release of extracellular vesicles (EVs). We hypothesized that combining the regenerative ability of MSCs and the significant advantages of NMP may improve the quality and utilization rate of organs, especially marginal organs. In this study, we review different strategies for liver preservation in vitro, as well as their strengths and weaknesses. We also introduce MSCs, derived EVs, and MSCs applications in liver preservation in vitro. Finally, we discuss the current challenges and future trends of MSCs applications for in vitro liver preservation. We envision novel bioreactor designs that employ 3D cell culturing and offer the possibility to reconstruct MSCs microenvironments to promote cell growth and biofunction expression. Large-scale MSCs production can be combined with normothermic machine perfusion to enhance in vitro liver preservation, thereby promoting donor organ function to benefit recipients in need of liver transplantation., (© The Author(s) 2023. Published by Oxford University Press.)

Organ transplantation remains the only treatment option for patients with end-stage organ failure. The last decade has seen a flurry of activity in improving organ preservation technologies, which promise to increase utilization in a dramatic fashion. They also bring the promise of extending the preservation duration significantly, which opens the doors to sharing organs across local and international boundaries and transforms the field. In this work, we review the recent literature on machine perfusion of livers across various protocols in development and clinical use, in the context of extending the preservation duration. We then review the next generation of technologies that have the potential to further extend the limits and open the door to banking organs, including supercooling, partial freezing, and nanowarming, and outline the opportunities arising in the field for researchers in the short and long term., Competing Interests: Some authors declare competing interests. KU, JB, and MT have patent applications relevant to this study. KU and MT have a financial interest in and serve on the Scientific Advisory Board for Sylvatica Biotech Inc., a company focused on developing high subzero organ preservation technology. Competing interests for MGH investigators are managed by MGH and MGB in accordance with their conflict-of-interest policies. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. KU declares that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (© 2023 Ozgur, Namsrai, Pruett, Bischof, Toner, Finger and Uygun.)

The realm of extended criteria liver transplantation created the 'adjacent possible' for dynamic organ preservation. Machine perfusion of the liver greatly expanded donor organ preservation possibilities, reaching before unattainable goals, including the mitigation of ischemia-reperfusion injury, viability assessment, and organ reconditioning prior to transplantation. However, current scientific evidence lacks uniformity between studies, perfusion protocols, and acceptance criteria. Construction of collaborative research networks for sharing knowledge should, therefore, enable the development of high-level evidence and guidelines for machine perfusion utilization, including donor acceptance criteria. Finally, this approach shall guarantee conditions for further progress to occur., Competing Interests: Conflict-of-interest statement: The authors have no conflicts of interest to disclose., (©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.)