Changing Trends in Liver Transplantation: Challenges and Solutions

Sarcopenic obesity in patients awaiting liver transplant: Unique challenges for nutritional recommendations

Sarcopenic obesity increases the risk of mortality in patients with liver disease awaiting liver transplantation and in the post-transplant period. Nutrition recommendations for individuals with sarcopenia differ from recommendations for patients with obesity or sarcopenic obesity. While these nutrition guidelines have been established in non-cirrhotic patients, established guidelines for liver transplant candidates with sarcopenic obesity are lacking. In this paper, we review existing literature on sarcopenic obesity in patients with chronic liver disease and address opportunities to improve nutritional counseling in patients awaiting liver transplantation.

Geographic disparities in access to liver transplant for advanced cirrhosis: Time to ring the alarm!

Decompensated cirrhosis and hepatocellular cancer are major risk factors for mortality worldwide. Liver transplantation (LT), both live-donor LT or deceased-donor LT, are lifesaving, but there are several barriers toward equitable access. These barriers are exacerbated in the setting of critical illness or acute-on-chronic liver failure. Rates of LT vary widely worldwide but are lowest in lower-income countries owing to lack of resources, infrastructure, late disease presentation, and limited donor awareness. A recent experience by the Chronic Liver Disease Evolution and Registry for Events and Decompensation consortium defined these barriers toward LT as critical in determining overall survival in hospitalized cirrhosis patients. A major focus should be on appropriate, affordable, and early cirrhosis and hepatocellular cancer care to prevent the need for LT. Live-donor LT is predominant across Asian countries, whereas deceased-donor LT is more common in Western countries; both approaches have unique challenges that add to the access disparities. There are many challenges toward equitable access but uniform definitions of acute-on-chronic liver failure, improving transplant expertise, enhancing availability of resources and encouraging knowledge between centers, and preventing disease progression are critical to reduce LT disparities.

National Trends in Utilization of Normothermic Machine Perfusion in DCD Liver Transplantation

Background

In liver transplantation, advances in ex situ normothermic machine perfusion (NMP) have improved outcomes compared with traditional static cold storage (SCS) in donation after circulatory death (DCD) organs. We aimed to characterize trends in the utilization of NMP versus SCS in DCD liver transplantation in the United States.

Methods

This retrospective cohort study used data from the United Network for Organ Sharing database to identify recipient-donor adult liver transplant pairs from DCD donors from January 2016 to June 2022. Utilization of NMP and changes in donor risk index (DRI) and components between NMP and SCS were assessed across transplant year eras (2016-2018, 2019-2020, and 2021-2022). Statistical comparisons were made using the Kruskal-Wallis test or the chi-square test.

Results

A total of 3937 SCS and 127 NMP DCD donor transplants were included. Utilization of NMP ranged from ~0.4% to 3.5% from 2016 to 2021 and rose significantly to 11.2% in early 2022. Across transplant eras, median DRI increased significantly for SCS and NMP, but the magnitude of the increase was larger for NMP. With NMP DCDs, there were significant increases in median donor age, national share proportion, and "cold ischemic time" over time. Finally, there was a shift toward including higher DRI donors and higher model for end-stage liver disease score transplant recipients with NMP in later transplant eras.

Conclusions

In recent years, NMP utilization has increased and expanded to donors with higher DRI and recipients with higher model for end-stage liver disease score at transplant, suggesting increasing familiarity and risk tolerance with NMP technology. As NMP remains a relatively new technique, ongoing study of patient outcomes, organ allocation practices, and utilization patterns is critical.

No Improvement in Intention-to-treat Survival and Increasing Liver Nonutilization Rate During the MELD Era

BACKGROUND

Although post liver transplant survival rates have significantly improved during the past 2-3 decades, the trend in intention-to-treat (ITT) survival (survival from waitlist addition) has not been well studied.

METHODS

We conducted a retrospective analysis of Scientific Registry of Transplant Recipients data to determine the trend in ITT survival in liver transplant candidates. Adult (age ≧ 18 y) patients who were on the waitlist between the time period of March 1, 2002, to December 31, 2019 (n = 200 816) and deceased liver donors that were registered between the same time period (n = 152 593) were analyzed.

RESULTS

We found a constant increase in posttransplant survival rates; however, the ITT survival rates showed no statistically significant improvement through the study period. We observed significant linear increase in waitlist dropout rates over time. We also observed linear increase in liver nonutilization rate in both entire cases and brain-dead cases. Donor risk index increased significantly over the years; however, it was mostly driven by increase in donation after circulatory death cases; without donation after circulatory death cases, donor risk index was stable throughout the 17 y we observed.

CONCLUSIONS

The reason of the increased liver nonutilization rate is unclear; however, it is possible that reluctance to use high-risk organ to maintain better posttransplant outcomes contributed to this increase, which also could have led to increase in waitlist dropout rates and no improvements in ITT survival. Further investigation is warranted on the increased nonutilization rates to improve over all contribution of liver transplant to patient care.

L-GrAFT7 has High Accuracy in Predicting Early Allograft Failure after Liver Transplantation: A Multicenter Cohort Study in China

Background and Aims

Increasing utilization of extended criteria donor leads to an increasing rate of early allograft failure after liver transplantation. However, consensus of definition of early allograft failure is lacking.

Methods

A retrospective, multicenter study was performed to validate the Liver Graft Assessment Following Transplantation (L-GrAFT) risk model in a Chinese cohort of 942 adult patients undergoing primary liver transplantation at three Chinese centers. L-GrAFT (L-GrAFT7 and L-GrAFT10) was compared with existing models: the Early Allograft Failure Simplified Estimation (EASE) score, the model of early allograft function (MEAF), and the Early Allograft Dysfunction (EAD) model. Univariate and multivariate logistic regression were used to find risk factors of L-GrAFT high-risk group.

Results

L-GrAFT7 had an area under the curve of 0.85 in predicting 90-day graft survival, significantly superior to MEAF [area under the curve (AUC=0.78, p=0.044)] and EAD (AUC=0.78, p=0.006), while there was no statistical significance between the predicting abilities of L-GrAFT7 and EASE (AUC=0.84, p>0.05). Furthermore, L-GrAFT7 maintains good predicting ability in the subgroup of high-donor risk index (DRI) cases (AUC=0.83 vs. MEAF, p=0.007 vs. EAD, p=0.014) and recipients of donors after cardiac death (AUC=0.92 vs. EAD, p<0.001). Through multivariate analysis, pretransplant bilirubin level, units of packed red blood cells, and the DRI score were selected as independent risk factors of a L-GrAFT7 high-risk group.

Conclusions

The accuracy of L-GrAFT7 in predicting early allograft failure was validated in a Chinese multicenter cohort, indicating that it has the potential to become an accurate endpoint of clinical practice and transitional study of machine perfusion.

Should AI allocate livers for transplant? Public attitudes and ethical considerations

BACKGROUND

Allocation of scarce organs for transplantation is ethically challenging. Artificial intelligence (AI) has been proposed to assist in liver allocation, however the ethics of this remains unexplored and the view of the public unknown. The aim of this paper was to assess public attitudes on whether AI should be used in liver allocation and how it should be implemented.

METHODS

We first introduce some potential ethical issues concerning AI in liver allocation, before analysing a pilot survey including online responses from 172 UK laypeople, recruited through Prolific Academic.

FINDINGS

Most participants found AI in liver allocation acceptable (69.2%) and would not be less likely to donate their organs if AI was used in allocation (72.7%). Respondents thought AI was more likely to be consistent and less biased compared to humans, although were concerned about the "dehumanisation of healthcare" and whether AI could consider important nuances in allocation decisions. Participants valued accuracy, impartiality, and consistency in a decision-maker, more than interpretability and empathy. Respondents were split on whether AI should be trained on previous decisions or programmed with specific objectives. Whether allocation decisions were made by transplant committee or AI, participants valued consideration of urgency, survival likelihood, life years gained, age, future medication compliance, quality of life, future alcohol use and past alcohol use. On the other hand, the majority thought the following factors were not relevant to prioritisation: past crime, future crime, future societal contribution, social disadvantage, and gender.

CONCLUSIONS

There are good reasons to use AI in liver allocation, and our sample of participants appeared to support its use. If confirmed, this support would give democratic legitimacy to the use of AI in this context and reduce the risk that donation rates could be affected negatively. Our findings on specific ethical concerns also identify potential expectations and reservations laypeople have regarding AI in this area, which can inform how AI in liver allocation could be best implemented.

Defatting of Human Livers During Long-Term e x situ Normothermic Perfusion: Novel Strategy to Rescue Discarded Organs for Transplantation

OBJECTIVE

To develop a protocol for the defatting of steatotic liver grafts during long-term ex situ normothermic machine perfusion.

BACKGROUND

Despite the alarming increase in donor organ shortage, the highly prevalent fatty liver grafts are often discarded due to the risk of primary nonfunction. Effective strategies preventing such outcomes are currently lacking. An exciting new avenue is the introduction of ex situ normothermic machine perfusion (NMP), enabling a liver to remain fully functional for up to 2 weeks and providing a unique window of opportunity for defatting before transplantation.

METHODS

Over a 5-year period, 23 discarded liver grafts and 28 partial livers from our resection program were tested during ex situ normothermic machine perfusion. The steatosis degree was determined on serial biopsies by expert pathologists, and triglyceride contents were measured simultaneously.

RESULTS

Of 51 liver grafts, 20 were steatotic, with up to 85% macrovesicular steatosis, and were perfused for up to 12 days. Ten livers displayed marked (5 of which almost complete) loss of fat, while the other 10 did not respond to long-term perfusion. Successful defatting was related to prolonged perfusion, automated glucose control, circadian nutrition, and L-carnitine/fenofibrate supplementation. Pseudopeliotic steatosis and the associated activation of Kupffer/stellate cells were unexpected processes that might contribute to defatting. Synthetic and metabolic functions remained preserved for most grafts until perfusion ended.

CONCLUSION

Ex situ long-term perfusion effectively reduces steatosis while preserving organ viability and may in the future allow transplantation of primarily unusable high-risk grafts, significantly increasing the number of organs available for transplantation.

Liver Transplantation in People Living with HIV: Still an Experimental Procedure or Standard of Care?

Liver transplantation (LT) is the only curative treatment for various liver diseases, including acute liver failure, end-stage liver disease, and selected unresectable liver malignancies. Combination antiretroviral therapy has improved outcomes for people living with HIV (PLWH), transforming the status of acquired immune deficiency syndrome from a fatal disease to a chronic and manageable condition. These powerful antiviral therapies have not only increased the number of HIV+ enlisted patients by improving their survival but also made the use of HIV+ organs a viable option. In this review, we summarise current knowledge on the peculiarities of liver transplantation in PLWH. In particular, we focus on the indications, contraindications, specific considerations for treatment, and outcomes of LT in PLWH. Finally, we present available preliminary data on the use of HIV+ liver allografts.

Mycosis Fungoides in Solid-Organ Transplant Recipients: A Multicenter Retrospective Cohort Study

BACKGROUND

Mycosis fungoides (MF) in solid-organ transplant recipients (SOTRs) is rare, with limited data on disease characteristics.

OBJECTIVE

The aim was to study the characteristics of MF in SOTRs with an emphasis on the immunosuppressive therapy.

METHODS

A retrospective cohort of patients diagnosed with MF, who were also SOTRs, were followed at 3 cutaneous lymphoma outpatient clinics, between January 2010 and February 2022.

RESULTS

Ten patients were included (7 male; median ages at transplantation and at diagnosis of MF were 33 and 48 years, respectively; 40% were diagnosed before the age of 18 years). Median time from transplantation to diagnosis of MF was 8 years (range 0.5-22). Transplanted organs and immunosuppressive treatments included: liver (n = 5; 4 treated with tacrolimus, 1 with tacrolimus and prednisone), kidney (n = 3), liver and kidney (n = 1), and heart (n = 1), all treated with mycophenolic acid, tacrolimus, and prednisone. Nine had early-stage MF (IA - 4, IB - 5; 40% with early folliculotropic MF), treated with skin-directed therapies, in 2 combined with acitretin, achieving partial/complete response. One patient had advanced-stage MF (IIIA) with folliculotropic erythroderma, treated with ultraviolet A and narrow-band ultraviolet B with acitretin, achieving partial response. Immunosuppression was modified in 3. At last follow-up (median 4 years, range 1-8), no stage progression was observed; 5 had no evidence of disease, 5 had active disease (IA/IB - 4, III - 1).

CONCLUSIONS

MF in SOTRs is usually diagnosed at an early stage, with overrepresentation of folliculotropic MF, and of children. Immunosuppressive therapy alterations, not conducted in most patients, should be balanced against the risk of organ compromise/rejection. Disease course was similar to MF in immunocompetent patients, during the limited time of follow-up.

Evaluating the outcomes of donor-recipient age differences in young adults undergoing liver transplantation

The current liver allocation system may be disadvantaging younger adult recipients as it does not incorporate the donor-recipient age difference. Given the longer life expectancy of younger recipients, the influences of older donor grafts on their long-term prognosis should be elucidated. This study sought to reveal the long-term prognostic influence of the donor-recipient age difference in young adult recipients. Adult patients who received initial liver transplants from deceased donors between 2002 and 2021 were identified from the UNOS database. Young recipients (patients 45 years old or below) were categorized into 4 groups: donor age younger than the recipient, 0-9 years older, 10-19 years older, or 20 years older or above. Older recipients were defined as patients 65 years old or above. To examine the influence of the age difference in long-term survivors, conditional graft survival analysis was conducted on both younger and older recipients. Among 91,952 transplant recipients, 15,170 patients were 45 years old or below (16.5%); these were categorized into 6,114 (40.3%), 3,315 (21.9%), 2,970 (19.6%), and 2,771 (18.3%) for groups 1-4, respectively. Group 1 demonstrated the highest probability of survival, followed by groups 2, 3, and 4 for the actual graft survival and conditional graft survival analyses. In younger recipients who survived at least 5 years post-transplant, inferior long-term survival was observed when there was an age difference of 10 years or above (86.9% vs. 80.6%, log-rank p <0.01), whereas there was no difference in older recipients (72.6% vs. 74.2%, log-rank p =0.89). In younger patients who are not in emergent need of a transplant, preferential allocation of younger aged donor offers would optimize organ utility by increasing postoperative graft survival time.

Beyond donation to organ utilization in the USA

PURPOSE OF REVIEW

The deceased donor organ pool has broadened beyond young, otherwise healthy head trauma victims. But an abundance of donated organs only benefits patients if they are accepted, expeditiously transported and actually transplanted. This review focuses on postdonation challenges and opportunities to increase the number of transplants through improved organ utilization.

RECENT FINDINGS

We build upon recently proposed changes in terminology for measuring organ utilization. Among organs recovered for transplant, the nonuse rate (NUR REC ) has risen above 25% for kidneys and pancreata. Among donors, the nonuse rate (NUR DON ) has risen to 40% for livers and exceeds 70% for thoracic organs. Programme-level variation in offer acceptance rates vastly exceeds variation in the traditional, 1-year survival benchmark. Key opportunities to boost utilization include donation after circulatory death and hepatitis C virus (HCV)+ organs; acute kidney injury and suboptimal biopsy kidneys; older and steatotic livers.

SUMMARY

Underutilization of less-than-ideal, yet transplant-worthy organs remains an obstacle to maximizing the impact of the U.S. transplant system. The increased risk of inferior posttransplant outcomes must always be weighed against the risks of remaining on the waitlist. Advanced perfusion technologies; tuning allocation systems for placement efficiency; and data-driven clinical decision support have the potential to increase utilization of medically complex organs.

Real-time assessment of liver fat content using a filter-based Raman system operating under ambient light through lock-in amplification

During liver procurement, surgeons mostly rely on their subjective visual inspection of the liver to assess the degree of fatty infiltration, for which misclassification is common. We developed a Raman system, which consists of a 1064 nm laser, a handheld probe, optical filters, photodiodes, and a lock-in amplifier for real-time assessment of liver fat contents. The system performs consistently in normal and strong ambient light, and the excitation incident light penetrates at least 1 mm into duck fat phantoms and duck liver samples. The signal intensity is linearly correlated with MRI-calibrated fat contents of the phantoms and the liver samples.

Current status of liver transplantation for non-B non-C liver cirrhosis and hepatocellular carcinoma

Recently, non-B non-C chronic liver diseases, including alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH), have markedly increased worldwide. Liver transplantation (LT) is an effective curative therapy for hepatocellular carcinoma (HCC) as well as decompensated liver cirrhosis. In Japan, where the source of liver grafts is strongly dependent on living donors, efforts have been made to unify the indications for eligibility of HCC patients for LT, leading to the development of 5-5-500 criteria. Along with the expansion of eligibility for LT, the current changing trends in underlying liver diseases of LT recipients, which are related to the rising tide of non-B non-C cirrhosis and HCC, are highlighting the importance of peri-transplant management of patients with various comorbidities. The post-LT prognosis of patients with ALD is significantly affected by de novo malignancies and metabolic syndrome-related complications as well as posttransplant alcohol relapse. NAFLD/NASH patients often suffer from obesity, type 2 diabetes mellitus, and other metabolic syndrome-related disorders, and nonneoplastic factors such as cardiovascular events and recurrence of NAFLD/NASH have a significant impact on post-LT outcomes. Patient management in the peri-transplant period as well as risk assessment for LT are key to improving post-LT outcomes in the era of a growing number of cases of LT for non-B non-C liver diseases.

A new detection system for serum fragmented cytokeratin 18 as a biomarker reflecting histologic activities of human nonalcoholic steatohepatitis

Caspase-generated fragmented cytokeratin 18 (fCK18) is recognized as a useful noninvasive biomarker in the diagnosis of nonalcoholic fatty liver disease (NAFLD), particularly nonalcoholic steatohepatitis (NASH). However, fCK18 measurement is not applied clinically due to widely variable cut-off values under the current enzyme-linked immunosorbent assay platform. Therefore, we developed a highly sensitive chemiluminescent enzyme immunoassay using newly developed monoclonal antibodies against fCK18 and investigated its relevance in NASH diagnosis. Serum fCK18 levels were measured in the derivation and validation cohort. The correlation between serum fCK18 levels and NAFLD activity score (NAS), fibrosis stage, and liver function was examined. Serum fCK18 levels were significantly correlated with alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase. Serum fCK18 levels were significantly associated with NAS, Brunt's grade/stage, Matteoni's classification, portal inflammation, and fat accumulation in the liver. Notably, hepatocyte ballooning was the only independent variable significantly associated with serum fCK18 in the multivariate linear regression analysis. Serum fCK18 levels were significantly elevated in patients with NAFLD and nonalcoholic fatty liver (NAFL) compared to healthy individuals. They were also significantly elevated in patients with NAFL compared to NASH defined by NAS or Matteoni's classification, with area under the curve values being 0.961 (NAFLD vs. healthy), 0.913 (NAFL vs. healthy), 0.763 (NASH vs. NAFL), and 0.796 (NASH type 3-4 vs. NAFL type 1-2). These results were confirmed by a validation cohort. Notably, changes over time in serum fCK18 levels were significantly correlated with changes in ALT, AST, and the fibrosis-4 index in 25 patients who underwent lifestyle modification. Serum fCK18 levels were significantly correlated with liver damage associated with NASH pathology. Serum fCK18 levels are accurate in distinguishing patients with NAFL or NASH from healthy individuals and may be useful to monitor NASH over time.

HBV-positive and HIV-positive organs in transplantation: A clinical guide for the hepatologist

Organ transplantation is a life-saving treatment for patients with end-stage organ disease, a severe condition associated with a high risk of waitlist mortality. It is primarily limited by a shortage of available organs. Maximising available donors can increase access to transplantation. Transplantation from donors positive for HBV and HIV has increased in many countries. However, antiviral therapies need to be readily available for recipients after transplantation to prevent possible reactivation of the virus following the administration of immunosuppressive therapies. Furthermore, the intentional transmission of a virus has practical, ethical, and clinical implications. In this review, we summarise the current research, focusing on grafts from donors positive for the HBV surface antigen, antibodies against the HBV core antigen, and HIV, to help hepatologists and physicians interested in transplantation to select the best antiviral and/or prophylactic regimens for after transplantation.

Prädiktoren für erfolgreiche Lebertransplantationen und Risikofaktoren

Die Lebertransplantation ist die einzige kurative Therapieoption einer chronischen Leberinsuffizienz im Endstadium. Daneben stellen onkologische Lebererkrankungen wie das HCC eine weitere Indikation für die Lebertransplantation dar, ebenso wie das akute Leberversagen.

Seit der ersten erfolgreichen Lebertransplantation durch Professor Thomas E. Starzl im Jahr 1967 haben sich nicht nur die chirurgischen, immunologischen und anästhesiologischen Techniken und Möglichkeiten geändert, sondern auch die Indikationen und das Patientengut. Hinzu kommt, dass die Empfänger ein zunehmendes Lebensalter und damit einhergehend mehr Begleiterkrankungen aufweisen.

Die Zahl an Lebertransplantationen ist weltweit weiter ansteigend. Es benötigen aber mehr Menschen eine Lebertransplantation, als Organe zur Verfügung stehen. Dies liegt am zunehmenden Bedarf an Spenderorganen bei gleichzeitig weiter rückläufiger Zahl postmortaler Organspenden.

Diese Diskrepanz zwischen Spenderorganen und Empfängern kann nur zu einem kleinen Teil durch Split-Lebertransplantationen oder die Leberlebendspende kompensiert werden.

Um den Spenderpool zu erweitern, werden zunehmend auch marginale Organe, die nur die erweiterten Spenderkriterien („extended donor criteria [EDC]“) erfüllen, allokiert. In manchen Ländern zählen hierzu auch die sogenannten DCD-Organe (DCD: „donation after cardiac death“), d. h. Organe, die erst nach dem kardiozirkulatorischen Tod des Spenders entnommen werden.

Es ist bekannt, dass marginale Spenderorgane mit einem erhöhten Risiko für ein schlechteres Transplantat- und Patientenüberleben nach Lebertransplantation einhergehen.

Um die Qualität marginaler Spenderorgane zu verbessern, hat sich eine rasante Entwicklung der Techniken der Organkonservierung über die letzten Jahre gezeigt. Mit der maschinellen Organperfusion besteht beispielsweise die Möglichkeit, die Organqualität deutlich zu verbessern. Insgesamt haben sich die Risikokonstellationen von Spenderorgan und Transplantatempfänger deutlich geändert.

Aus diesem Grunde ist es von großer Bedeutung, spezifische Prädiktoren für eine erfolgreiche Lebertransplantation sowie die entsprechenden Risikofaktoren für einen schlechten postoperativen Verlauf zu kennen, um das bestmögliche Transplantat- und Patientenüberleben nach Lebertransplantation zu ermöglichen.

Diese Einflussfaktoren, inklusive möglicher Risiko-Scores, sollen hier ebenso wie die neuen technischen Möglichkeiten in der Lebertransplantation beleuchtet werden.

Hyperspectral Imaging as a Tool for Viability Assessment During Normothermic Machine Perfusion of Human Livers: A Proof of Concept Pilot Study

Normothermic machine perfusion (NMP) allows for ex vivo viability and functional assessment prior to liver transplantation (LT). Hyperspectral imaging represents a suitable, non-invasive method to evaluate tissue morphology and organ perfusion during NMP. Liver allografts were subjected to NMP prior to LT. Serial image acquisition of oxygen saturation levels (StO2), organ hemoglobin (THI), near-infrared perfusion (NIR) and tissue water indices (TWI) through hyperspectral imaging was performed during static cold storage, at 1h, 6h, 12h and at the end of NMP. The readouts were correlated with perfusate parameters at equivalent time points. Twenty-one deceased donor livers were included in the study. Seven (33.0%) were discarded due to poor organ function during NMP. StO2 (p < 0.001), THI (p < 0.001) and NIR (p = 0.002) significantly augmented, from static cold storage (pre-NMP) to NMP end, while TWI dropped (p = 0.005) during the observational period. At 12-24h, a significantly higher hemoglobin concentration (THI) in the superficial tissue layers was seen in discarded, compared to transplanted livers (p = 0.036). Lactate values at 12h NMP correlated negatively with NIR perfusion index between 12 and 24h NMP and with the delta NIR perfusion index between 1 and 24h (rs = -0.883, p = 0.008 for both). Furthermore, NIR and TWI correlated with lactate clearance and pH. This study provides first evidence of feasibility of hyperspectral imaging as a potentially helpful contact-free organ viability assessment tool during liver NMP.

Patients with liver cirrhosis due to nonalcoholic steatohepatitis have lesser chances for liver transplantation

BACKGROUND

The main causes of liver cirrhosis have changed over the past decade. In Japan, the number of deceased donors is increasing but is still insufficient relative to the number of patients awaiting a liver transplant. This study aimed to assess the outcomes of candidates for liver transplantation.

METHODS

This was a retrospective study of adult patients who visited our department for consultation regarding liver transplantation from January 2009 to December 2020. Of a total of 601 patients, 336 were followed-up. The following data were collected and analyzed: patient's characteristics, liver etiology, Child-Pugh and MELD scores, and the eventual outcome, that is, whether liver transplantation was performed.

RESULTS

Only 153 of 336 (45.5%) patients underwent liver transplantation, of which 42 (27.5%) received deceased donor liver transplantation, and 129 (38.4%) died without transplantation. The proportion of patients who underwent liver transplantation was low among patients with nonalcoholic steatohepatitis (NASH) (10.7%) (P<0.001). The rate of qualified living donors was the lowest for patients with NASH (28.6%) and that for the other etiologies ranged from 55.6% to 67.4% (P=0.050).

CONCLUSION

Patients with liver cirrhosis due to NASH may have a lesser chance of undergoing liver transplantation from both living and deceased donors.

Lipoxygenases in chronic liver diseases: current insights and future perspectives

Chronic liver diseases (CLDs) caused by viral infections, alcohol/drug abuse, or metabolic disorders affect millions of people globally and have increased mortality owing to the lack of approved therapies. Lipoxygenases (LOXs) are a family of multifaceted enzymes that are responsible for the oxidation of polyunsaturated fatty acids (PUFAs) and are implicated in the pathogenesis of multiple disorders including liver diseases. This review describes the three main LOX signaling pathways - 5-, 12-, and 15-LOX - and their involvement in CLDs. We also provide recent insights and future perspectives on LOX-related hepatic pathophysiology, and discuss the potential of LOXs and LOX-derived metabolites as diagnostic biomarkers and therapeutic targets in CLDs.

The Need to Update Endpoints and Outcome Analysis in the Rapidly Changing Field of Liver Transplantation

Liver transplantation (LT) survival rates have continued to improve over the last decades, mostly due to the reduction of mortality early after transplantation. The advancement is facilitating a liberalization of access to LT, with more patients with higher risk profiles being added to the waiting list. At the same time, the persisting organ shortage fosters strategies to rescue organs of high-risk donors. This is facilitated by novel technologies such as machine perfusion. Owing to these developments, reconsideration of the current and emerging endpoints for the assessment of the efficacy of existing and new therapies is warranted. While conventional early endpoints in LT have focused on the damage induced to the parenchyma, the fate of the bile duct and the recurrence of the underlying disease have a stronger impact on the long-term outcome. In light of this evolving landscape, we here attempt to reflect on the appropriateness of the currently used endpoints in the field of LT trials.

A Simple and Quick Screening Method for Intrapulmonary Vascular Dilation in Cirrhotic Patients Based on Machine Learning

Background and Aims

Screening for hepatopulmonary syndrome in cirrhotic patients is limited due to the need to perform contrast enhanced echocardiography (CEE) and arterial blood gas (ABG) analysis. We aimed to develop a simple and quick method to screen for the presence of intrapulmonary vascular dilation (IPVD) using noninvasive and easily available variables with machine learning (ML) algorithms.

Methods

Cirrhotic patients were enrolled from our hospital. All eligible patients underwent CEE, ABG analysis and physical examination. We developed a two-step model based on three ML algorithms, namely, adaptive boosting (termed AdaBoost), gradient boosting decision tree (termed GBDT) and eXtreme gradient boosting (termed Xgboost). Noninvasive variables were input in the first step (the NI model), and for the second step (the NIBG model), a combination of noninvasive variables and ABG results were used. Model performance was determined by the area under the curve of receiver operating characteristics (AUCROCs), precision, recall, F1-score and accuracy.

Results

A total of 193 cirrhotic patients were ultimately analyzed. The AUCROCs of the NI and NIBG models were 0.850 (0.738–0.962) and 0.867 (0.760–0.973), respectively, and both had an accuracy of 87.2%. For both negative and positive cases, the recall values of the NI and NIBG models were both 0.867 (0.760–0.973) and 0.875 (0.771–0.979), respectively, and the precisions were 0.813 (0.690–0.935) and 0.913 (0.825–1.000), respectively.

Conclusions

We developed a two-step model based on ML using noninvasive variables and ABG results to screen for the presence of IPVD in cirrhotic patients. This model may partly solve the problem of limited access to CEE and ABG by a large numbers of cirrhotic patients.

Hyperspectral Imaging and Machine Perfusion in Solid Organ Transplantation: Clinical Potentials of Combining Two Novel Technologies

Organ transplantation survival rates have continued to improve over the last decades, mostly due to reduction of mortality early after transplantation. The advancement of the field is facilitating a liberalization of the access to organ transplantation with more patients with higher risk profile being added to the waiting list. At the same time, the persisting organ shortage fosters strategies to rescue organs of marginal donors. In this regard, hypothermic and normothermic machine perfusion are recognized as one of the most important developments in the modern era. Owing to these developments, novel non-invasive tools for the assessment of organ quality are on the horizon. Hyperspectral imaging represents a potentially suitable method capable of evaluating tissue morphology and organ perfusion prior to transplantation. Considering the changing environment, we here discuss the hypothetical combination of organ machine perfusion and hyperspectral imaging as a prospective feasibility concept in organ transplantation.

Emerging therapeutic approaches for the treatment of NAFLD and type 2 diabetes mellitus

Non-alcoholic fatty liver disease (NAFLD) has emerged as the most prevalent liver disease in the world, yet there are still no approved pharmacological therapies to prevent or treat this condition. NAFLD encompasses a spectrum of severity, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). Although NASH is linked to an increased risk of hepatocellular carcinoma and cirrhosis and has now become the leading cause of liver failure-related transplantation, the majority of patients with NASH will ultimately die as a result of complications of type 2 diabetes mellitus (T2DM) and cardiometabolic diseases. Importantly, NAFLD is closely linked to obesity and tightly interrelated with insulin resistance and T2DM. Thus, targeting these interconnected conditions and taking a holistic attitude to the treatment of metabolic disease could prove to be a very beneficial approach. This Review will explore the latest relevant literature and discuss the ongoing therapeutic options for NAFLD focused on targeting intermediary metabolism, insulin resistance and T2DM to remedy the global health burden of these diseases.

Intent-to-treat survival in liver transplantation has not improved in 3 decades due to donor shortage relative to waitlist growth

BACKGROUND

Liver Transplantation has advanced over the past 3 decades, with 1-year survival rates improving 25%. Survival rates for those transplanted has increased to remarkable levels, but survival from the time of listing may not be as revolutionary.

METHODS

Kaplan-Meier with log-rank test as well as Cox regression analysis was used to retrospectively analyze 211 610 adults listed for LT and 116 299 adult transplant recipients from 1987 to 2016. Our primary endpoints were survival from time of listing to waitlist death or posttransplant death.

RESULTS

One-year survival following LT improved dramatically (68% in 1987-1988 vs. 93% in 2016, P < .001). There was no improvement in 1-year intent-to-treat survival: 78.4% for those listed in 1987 and 81.8% for those listed in 2016 (P = .1). Also observed were decreases in the percentage of transplanted candidates from 74.8% in 1987-1988 to 54.7% in 2016 (P < .001) and increased 1-year wait-list mortality from 12.5% in 1987-1988 to 22.6% in 2016 (P = .002).

CONCLUSION

As transplant rate has decreased while waitlist mortality has increased, no improvements have been made in intent-to-treat survival of patients listed for transplant over the past 3 decades. We speculate this observation to be resultant of a relative donor shortage outpaced by waitlist growth.

SUMMARY

Liver Transplantation has experienced vast increases in survival rates over the past 3 decades; however, due to an increased donor supply outpaced by waitlist growth, the rate of transplantation has decreased significantly while the waitlist mortality has increased, leading to no improvement in 1-year intent-to-treat survival rates.