Hypothermic machine perfusion versus cold storage in the rescuing of livers from non-heart-beating donor rats

Appropriate timing for hypothermic machine perfusion to preserve livers donated after circulatory death

Hypothermic machine perfusion (HMP) is a method that can be more effective in preserving donor organs compared with cold storage (CS). However, the optimal duration and the exact mechanisms of the protevtive effects of HMP remain unknow. The present study aimed to investigate the adequate perfusion time and mechanisms underlying HMP to protect livers donated after circulatory death (DCD). After circulatory death, adult male Sprague-Dawley rat livers were subjected to 30 min of warm ischemia (WI) and were subsequently preserved by HMP or CS. To determine the optimal perfusion time, liver tissues were analyzed at 0, 1, 3, 5, 12 and 24 h post-preservation to evaluate injury and assess the expression of relevant proteins. WI livers were preserved by HMP or CS for 3 h, and liver viability was evaluated by normothermic reperfusion (NR). During NR, oxygen consumption, bile production and the activities of hepatic enzymes in the perfusate were assessed. Following 2 h of NR, levels of inflammation and oxidative stress were determined in the livers and perfusate. HMP for 3 h resulted in the highest expression of myocyte enhancer factor 2C (MEF2C) and kruppel-like factor 2 (KLF2) and the lowest expression of NF-κB p65, tumor necrosis factor (TNF)-α and interleukin (IL)-1β among the different timepoints, which indicated that 3 h may be the optimal time for HMP induction of the KLF2-dependent signaling pathway. Compared with CS-preserved livers, HMP-preserved livers displayed significantly higher oxygen consumption, lower hepatic enzyme levels in the perfusate following NR. Following HMP preservation, the expression levels of MEF2C, KLF2, endothelial nitric oxide synthase and nitric oxide were increased, whereas the expression levels of NF-κB p65, IL-1β and TNF-α were decreased compared with CS preservation. The results indicated that 3 h may be the optimal time for HMP to protect DCD rat livers. Furthermore, HMP may significantly reduce liver inflammation and oxidative stress injury by mediating the KLF2/NF-κB/eNOS-dependent signaling pathway.

The Novel N,N-bis-2-Hydroxyethyl-2-Aminoethanesulfonic Acid-Gluconate-Polyethylene Glycol-Hypothermic Machine Perfusion Solution Improves Static Cold Storage and Reduces Ischemia/Reperfusion Injury in Rat Liver Transplant

Organ transplantation is the treatment of choice against terminal and irreversible organ failure. Optimal preservation of the graft is crucial to counteract cold ischemia effects. As we developed an N,N-bis-2-hydroxyethyl-2-aminoethanesulfonic acid-gluconate-polyethylene glycol (BGP)-based solution (hypothermic machine perfusion [HMP]), we aimed to analyze the use of this solution on static cold storage (SCS) of rat livers for transplantation as compared with the histidine tryptophan ketoglutarate (HTK) preservation solution. Livers procured from adult male Sprague Dawley rats were preserved with BGP-HMP or HTK solutions. Liver total water content and metabolites were measured during the SCS at 0°C for 24 hours. The function and viability of the preserved rat livers were first assessed ex vivo after rewarming (90 minutes at 37°C) and in vivo using the experimental model of reduced-size heterotopic liver transplantation. After SCS, the water and glycogen content in both groups remained unchanged as well as the tissue glutathione concentration. In the ex vivo studies, livers preserved with the BGP-HMP solution were hemodynamically more efficient and the O₂ consumption rate was higher than in livers from the HTK group. Bile production and glycogen content after 90 minutes of normothermic reperfusion was diminished in both groups compared with the control group. Cellular integrity of the BGP-HMP group was better, and the histological damage was reversible. In the in vivo model, HTK-preserved livers showed a greater degree of histological injury and higher apoptosis compared with the BGP-HMP group. In conclusion, our results suggest a better role of the BGP-HMP solution compared with HTK in preventing ischemia/reperfusion injury in the rat liver model.

Organ Preservation into the 2020s: The Era of Dynamic Intervention

Organ preservation has been of major importance ever since transplantation developed into a global clinical activity. The relatively simple procedures were developed on a basic comprehension of low-temperature biology as related to organs outside the body. In the past decade, there has been a significant increase in knowledge of the sequelae of effects in preserved organs, and how dynamic intervention by perfusion can be used to mitigate injury and improve the quality of the donated organs. The present review focuses on (1) new information about the cell and molecular events impacting on ischemia/reperfusion injury during organ preservation, (2) strategies which use varied compositions and additives in organ preservation solutions to deal with these, (3) clear definitions of the developing protocols for dynamic organ perfusion preservation, (4) information on how the choice of perfusion solutions can impact on desired attributes of dynamic organ perfusion, and (5) summary and future horizons.

Post-reperfusion hydrogen gas treatment ameliorates ischemia reperfusion injury in rat livers from donors after cardiac death: a preliminary study

BACKGROUND AND PURPOSE

We reported previously that hydrogen gas (H₂) reduced hepatic ischemia and reperfusion injury (IRI) after prolonged cold storage (CS) of livers retrieved from heart-beating donors. The present study was designed to assess whether H₂ reduced hepatic IRI during donation of a cardiac death (DCD) graft with subsequent CS.

METHODS

Rat livers were harvested after 30-min cardiac arrest and stored for 4 h in University of Wisconsin solution. The graft was reperfused with oxygenated buffer, with or without H₂ (H₂ or NT groups, respectively), at 37° for 90 min on isolated perfused rat liver apparatus.

RESULTS

In the NT group, liver enzyme leakage, apoptosis, necrosis, energy depletion, redox status, impaired microcirculation, and bile production were indicative of severe IRI, whereas in the H₂ group these impairments were significantly suppressed. The phosphorylation of cytoplasmic MKK4 and JNK were enhanced in the NT group and suppressed in the H₂ group. NFkB-p65 and c-Fos in the nucleus were unexpectedly unchanged by IRI regardless of H₂ treatment, indicating the absence of inflammation in this model.

CONCLUSION

H₂ was observed to ameliorate IRI in the DCD liver by maintaining microcirculation, mitochondrial functions, and redox status, as well as suppressing the cytoplasmic MKK4-JNK-mediated cellular death pathway.

Hypothermic oxygenated perfusion (HOPE) attenuates ischemia/reperfusion injury in the liver through inhibition of the TXNIP/NLRP3 inflammasome pathway in a rat model of donation after cardiac death

Hypothermic oxygenated perfusion (HOPE) is a relatively new dynamic preservation procedure that has not been widely implemented in liver transplantation despite its advantages. Improved graft protection is one such advantage offered by HOPE and has been attributed to multiple mechanisms, one of which may be the modulation of the thioredoxin-interacting protein (TXNIP)/NOD-like receptor protein 3 (NLRP3) inflammasome pathway. The TXNIP/NLRP3 inflammasome pathway plays a critical role in sterile inflammation under oxidative stress as a result of ischemia/reperfusion injury (IRI). In the current study, we aimed to investigate the graft protection offered by HOPE and its impact on the TXNIP/NLRP3 inflammasome pathway. To simulate conditions of donation after cardiac death (DCD) liver transplantation, rat livers were exposed to 30 min of warm ischemia after cardiac arrest. Livers were then preserved under cold storage (CS) or with HOPE for 3 h. Livers were then subjected to 1 h of isolated reperfusion. Liver injuries were assessed on the isolated perfusion rat liver model system before and after reperfusion. Compared with the CS group, the HOPE group had a significant reduction in liver injury and improvement in liver function. Our findings also revealed that reperfusion injury induced liver damage and activated the TXNIP/NLRP3 inflammasome pathway in DCD rat livers. Pretreatment of DCD rat livers with HOPE inhibited the TXNIP/NLRP3 inflammasome pathway and attenuated liver IRI. Attenuation of oxidative stress as a result of HOPE led to the down-regulation of the TXNIP/NLRP3 inflammasome pathway and thus offered superior protection compared with the traditional CS method of organ preservation.-He, W., Ye, S., Zeng, C., Xue, S., Hu, X., Zhang, X., Gao, S., Xiong, Y., He, X., Vivalda, S., Li, L., Wang, Y., Ye, Q. Hypothermic oxygenated perfusion (HOPE) attenuates ischemia/reperfusion injury in the liver through inhibition of the TXNIP/NLRP3 inflammasome pathway in a rat model of donation after cardiac death.

Hypothermic machine perfusion attenuates ischemia/reperfusion injury against rat livers donated after cardiac death by activating the Keap1/Nrf2‑ARE signaling pathway

Hypothermic machine perfusion (HMP) has been demonstrated to be a more effective method for preserving livers donated after circulatory death (DCD) than cold storage (CS); however, the underlying mechanisms remain unclear. The aim of the present study was to investigate the protective effects of HMP on rat DCD livers and the possible role of the nuclear factor erythroid 2‑related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway. A total of 18 adult male rats were randomly divided into three groups: Control, HMP and CS (n=6 per group). To simulate the conditions of DCD liver transplantation, rat livers in the CS and HMP groups were subjected to 30 min warm ischemia following cardiac arrest and were then preserved by CS or HMP for 3 h. Subsequently, after 1 h of isolated reperfusion, the extent of ischemia/reperfusion injury (IRI) and cellular functions were assessed. During reperfusion, intrahepatic resistance and bile production were measured, and the perfusion fluid was collected for liver enzyme analysis. The liver tissues were then harvested for the assessment of malondialdehyde (MDA) production, superoxide dismutase (SOD) activity, ATP levels, as well as for histological analysis, immunohistochemistry and a terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Finally, the expression levels of the components associated with the Nrf2‑ARE signaling pathway were analyzed via western blotting and reverse transcription‑quantitative polymerase chain reaction. The results of the present study revealed that, compared with in the CS group, the HMP group exhibited higher levels of ATP, bile production and SOD activity, and improved histological results; however, lower levels of liver enzymes, apoptosis and MDA were detected. Additionally, the findings of the present study also suggested that the Nrf2‑ARE signaling pathway may be activated by the steady laminar flow of HMP. In conclusion, HMP may attenuate ischemia‑reperfusion injury to rat DCD livers via activation of the Nrf2‑ARE signaling pathway.

A novel hypothermic machine perfusion system using a LifePort Kidney Transporter for the preservation of rat liver

The protective mechanisms for liver preservation associated with hypothermic machine perfusion (HMP) remain unclear. However, the lack of a common and portable HMP system for rat livers limits the study of HMP. The present study aimed to develop a novel, modified HMP system using a LifePort Kidney Transporter for preserving rat livers. A simple ‘Y’ shunt combined with a pressoreceptor for flow and pressure regulation was adapted to perfuse rat livers via the portal vein continuously using a LifePort Kidney Transporter under its ‘prime mode’ setting. An electronic scale was installed under the liver container to calculate the portal inflow according to the association with weight, density and volume of the perfusate. A total of 10 rat livers underwent 6 h of HMP using histidine-tryptophan-ketoglutarate solution enriched with acridine orange (AO) and propidium iodide (PI). The perfusion status of HMP was assessed by comparison of AO+PI-positive cell count in core region (CR) and peripheral region (PR) of rat liver under fluorescence microscopy. The dynamics (inflow, pressure and intrahepatic resistance of perfusion) were assessed to identify whether this system met the demands for HMP of rat livers. Biochemical [alanine transaminase (ALT), lactate dehydrogenase (LDH) and endothelin levels] and histological parameters (sinusoidal dilatation, endothelial cell detachment and vacuolization) were measured to determine cellular damage associated with HMP. No significant difference was observed between the CR and PR according to the comparison of the AO+PI-positive cell count, which indicated that complete perfusion was achieved. Intrahepatic resistance significantly decreased during the initial 3 h of HMP (P<0.01), but remained stable during the final 3 h. ALT and LDH levels significantly increased over the 6 h HMP duration: ALT (0 h, 42.67±5.81 U/l; 3 h, 90.67±6.74 U/l; 6 h, 164.33±7.31 U/l; P<0.01) and LDH (0 h, 492.90±90.20 U/l; 3 h, 973.53±97.4; 6 h, 1,843.40±85.78 U/l; P<0.01) However, the levels of endothelin and oxygen consumption were constant throughout HMP. Furthermore, histological analysis indicated sinusoidal dilation was significantly increased in the post-HMP group compared with the pre-HMP group (P<0.01); however, no other significant differences were observed. Combined with the results of ATP test (640.64±29.46 nmol/l) and bile production (4.88±0.69 µl/h/g of liver) at the end of HMP, the present results demonstrated minimal cellular injury associated with HMP while retaining the dependability and portability of the LifePort Kidney Transporter, which suggests the modified HMP system met the demands required and may be suitable for rat liver preservation.

Hypothermic machine perfusion ameliorates inflammation during ischemia‑reperfusion injury via sirtuin‑1‑mediated deacetylation of nuclear factor‑κB p65 in rat livers donated after circulatory death

Hypothermic machine perfusion (HMP) effectively reduces ischemia-reperfusion injury (IRI) in livers donated after circulatory death (DCD) when compared with cold storage (CS). However, the underlying mechanisms remain unclear. The current study aimed to investigate the cellular mechanisms by which HMP ameliorates the inflammatory response during IRI. Adult male Sprague-Dawley rat livers were exposed to 30 min of warm ischemia following cardiac arrest and preserved by CS or HMP for 3 h (n=3 per group). The severity of IRI was assessed in vitro on normothermic reperfusion for 2 h, and intrahepatic resistance (IHR) and bile production were subsequently recorded. The perfusate was analyzed for transaminase leakage and oxygen consumption. Livers were subsequently subjected to histological examination, and measurement of adenosine triphosphate (ATP) levels, malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, nicotinamide adenine dinucleotide (NAD)⁺ levels and the ratio of NAD⁺/NADH. In addition, the protein expression of sirtuin-1 (SIRT-1), acetylated-nuclear factor-κB (NF-κB) p65 and NF-κB p65 was detected by western blotting, and the mRNA expression of the inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α was determined by reverse transcription-quantitative polymerase chain reaction. Compared with CS, HMP resulted in significantly lower IHR, transaminase leakage and MDA levels, and higher oxygen consumption, ATP levels and SOD activity. In addition, improved preservation of hepatic histology was observed in HMP compared with CS. The mRNA expression of NF-κB p65, IL-6 and TNF-α was significantly decreased in the HMP group compared with CS samples. Under HMP preservation, SIRT-1 activity and protein expression were increased, while the protein expression of acetylated-NF-κB p65 was decreased, compared with CS. These results indicate that HMP may reduce the inflammatory response during IRI via SIRT-1-mediated deacetylation of NF-κB p65. These findings may provide a theoretical basis for the clinical application of HMP as an effective strategy to preserve DCD livers.

Machine perfusion versus cold storage of livers: a meta-analysis

Different organ preservation methods are key factors influencing the results of liver transplantation. In this study, the outcomes of experimental models receiving donation after cardiac death (DCD) livers preserved through machine perfusion (MP) or static cold storage (CS) were compared by conducting a meta-analysis. Standardized mean difference (SMD) and 95% confidence interval (CI) were calculated to compare pooled data from two animal species. Twenty-four studies involving MP preservation were included in the meta-analysis. Compared with CS preservation, MP can reduce the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and hyaluronic acid (HA) and the changes in liver weight. By contrast, MP can enhance bile production and portal vein flow (PVF). Alkaline phosphatase (ALP) levels and histological changes significantly differed between the two preservation methods. In conclusion, MP of DCD livers is superior to CS in experimental animals.

Machine Perfusion of Donor Livers for Transplantation: A Proposal for Standardized Nomenclature and Reporting Guidelines

With increasing demand for donor organs for transplantation, machine perfusion (MP) promises to be a beneficial alternative preservation method for donor livers, particularly those considered to be of suboptimal quality, also known as extended criteria donor livers. Over the last decade, numerous studies researching MP of donor livers have been published and incredible advances have been made in both experimental and clinical research in this area. With numerous research groups working on MP, various techniques are being explored, often applying different nomenclature. The objective of this review is to catalog the differences observed in the nomenclature used in the current literature to denote various MP techniques and the manner in which methodology is reported. From this analysis, we propose a standardization of nomenclature on liver MP to maximize consistency and to enable reliable comparison and meta-analyses of studies. In addition, we propose a standardized set of guidelines for reporting the methodology of future studies on liver MP that will facilitate comparison as well as clinical implementation of liver MP procedures.

Organ preservation review: history of organ preservation

PURPOSE OF REVIEW

To summarize the history of organ preservation and place into this context the current trends in preservation.

RECENT FINDINGS

Multiple large retrospective studies have analyzed cold preservation solutions in an attempt to determine superiority with largely negative results. Experimental and some clinical studies have examined machine perfusion of procured grafts, in both hypothermic and normothermic contexts with variable, but promising, results. Lastly, there are experimental efforts to evaluate mesenchymal stem cell therapy on rehabilitation of marginal donor organs.

SUMMARY

New trends in organ preservation may soon translate into more efficient use of the limited donor pool.

Artificial Organs 2013: a year in review

In this Editor's Review, articles published in 2013 are organized by category and briefly summarized. We aim to provide a brief reflection of the currently available worldwide knowledge that is intended to advance and better human life while providing insight for continued application of technologies and methods of organ Replacement, Recovery, and Regeneration. As the official journal of The International Federation for Artificial Organs, The International Faculty for Artificial Organs, the International Society for Rotary Blood Pumps, the International Society for Pediatric Mechanical Cardiopulmonary Support, and the Vienna International Workshop on Functional Electrical Stimulation, Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level". Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide so meaningful suggestions to the author's work whether eventually accepted or rejected and especially to those whose native tongue is not English. Without these excellent and dedicated reviewers the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, Wiley Periodicals, for their expert attention and support in the production and marketing of Artificial Organs. We look forward to recording further advances in the coming years.

Organomatics and organometrics: Novel platforms for long-term whole-organ culture

Organ culture systems are instrumental as experimental whole-organ models of physiology and disease, as well as preservation modalities facilitating organ replacement therapies such as transplantation. Nevertheless, a coordinated system of machine perfusion components and integrated regulatory control has yet to be fully developed to achieve long-term maintenance of organ function ex vivo. Here we outline current strategies for organ culture, or organomatics, and how these systems can be regulated by means of computational algorithms, or organometrics, to achieve the organ culture platforms anticipated in modern-day biomedicine.