Nonalcoholic Fatty Liver Disease: Key Considerations Before and After Liver Transplantation

Exercise Preconditioning of the Donor Liver Decreases Cold Ischemia/Reperfusion Injury in a Mouse Model

BACKGROUND

Liver transplantation stands as the primary treatment for end-stage liver disease, with demand surging in recent decades because of expanded indications. However, hepatic ischemia/reperfusion injury can lead to liver transplant failure in both deceased donor and living donor transplantation. This study explored whether preconditioning donor livers through exercise training (ExT) could mitigate cold ischemic injury posttransplantation.

METHODS

Donor C57BL/6 mice underwent ExT via treadmill running or remained sedentary. After 4 wk, the donor liver underwent cold storage and subsequent orthotopic liver transplantation or ex vivo warm reperfusion.

RESULTS

Donor liver from mice subjected to ExT showed significantly decreased hepatic injury on reperfusion. Tissue histology revealed decreased sinusoidal congestion, vacuolization, and hepatocellular necrosis in livers from ExT mice, and immunofluorescence staining further revealed a decreased number of apoptotic cells in ExT grafts. Livers from ExT donors expressed decreased intragraft inflammatory cytokines cascade, decreased neutrophil infiltration and neutrophil extracellular traps, and increased M2 phenotype of recipient macrophages compared with grafts from sedentary mice. After cold storage, liver grafts from ExT donors showed decreased accumulation of reactive oxygen species and decreased levels of cytochrome c and high mobility group box 1 released in the liver effluent. In addition, ExT grafts showed upregulated peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and higher levels of mitochondrial content. Similar effects of decreased hepatic injury were observed in wild-type mice when pretreated with a PGC-1α stimulator ZLN005 instead of ExT.

CONCLUSIONS

These findings suggest that augmenting hepatocytic mitochondrial content through donor exercise or PGC-1α stimulation may offer therapeutic avenues to mitigate postreperfusion inflammation and improve transplant outcomes.

Availability of living donor optimizes timing of liver transplant in high-risk waitlisted cirrhosis patients

Liver transplant (LT) candidates have become older and frailer, with growing Non-alcoholic steatohepatitis (NASH) and comorbid disease burden in recent years, predisposing them for poor waitlist outcomes. We aimed to evaluate the impact of access to living donor liver transplantation (LDLT) in waitlisted patients at highest risk of dropout. We reviewed all adult patients with decompensated cirrhosis listed for LT from November 2012 to December 2018. Patients with a potential living donor (pLD) available were identified. Survival analyses with Cox Proportional Hazards models and time to LT with Competing risk models were performed followed by prediction model development. Out of 860 patients who met inclusion criteria, 360 (41.8%) had a pLD identified and 496 (57.6%) underwent LT, out of which 170 (34.2%) were LDLT. The benefit of pLD was evident for all, but patients with moderate to severe frailty at listing (interaction p = 0.03), height <160 cm (interaction p = 0.03), and Model for end stage liver disease (MELD)-Na score <20 (interaction p < 0.0001) especially benefited. Our prediction model identified patients at highest risk of dropout while waiting for deceased donor and most benefiting of pLD (time-dependent area under the receiver operating characteristic curve 0.82). Access to LDLT in a transplant program can optimize the timing of transplant for the increasingly older, frail patient population with comorbidities who are at highest risk of dropout.

Clinical and financial outcomes of transplant recipients following emergency general surgery operations

Introduction

Due to immunosuppression and underlying comorbidities, transplant recipients represent a vulnerable population following emergency general surgery (EGS) operations. The present study sought to evaluate clinical and financial outcomes of transplant patients undergoing EGS.

Methods

The 2010-2020 Nationwide Readmissions Database was queried for adults (≥18 years) with non-elective EGS. Operations included bowel resection, perforated ulcer repair, cholecystectomy, appendectomy and lysis of adhesions. Patients were classified by transplant history (Non-transplant, Kidney/Pancreas, Liver, Heart/Lung). The primary outcome was in-hospital mortality while perioperative complications, resource utilization and readmissions were secondarily considered. Multivariable regression models evaluated the association of transplant status on outcomes. Entropy balancing was employed to obtain a weighted comparison to adjust for intergroup differences.

Results

Of 7,914,815 patients undergoing EGS, 25,278 (0.32 %) had prior transplantation. The incidence of transplant patients increased temporally (2010: 0.23 %, 2020: 0.36 %, p < 0.001) with Kidney/Pancreas comprising the largest proportion (63.5 %). Non-transplant more frequently underwent appendectomy and cholecystectomy while transplant patients more commonly received bowel resections. Following entropy balancing, Liver was associated with decreased odds of mortality (AOR: 0.67, 95 % CI: 0.54-0.83, Reference: Non-transplant). Incremental hospitalization duration was longer in Liver and Heart/Lung compared to Non-transplant. Odds of acute kidney injury, readmissions and costs were higher in all transplant types.

Conclusion

The incidence of transplant recipients undergoing EGS operations has increased. Liver was observed to have lower mortality compared to Non-transplant. Transplant recipient status, regardless of organ, was associated with greater resource utilization and non-elective readmissions. Multidisciplinary care coordination is warranted to mitigate outcomes in this high-risk population.

The epidemiology of non-alcoholic steatohepatitis (NASH) in the United States between 2010-2020: a population-based study

INTRODUCTION AND OBJECTIVES

Non-alcoholic steatohepatitis (NASH) is a severe form of non-alcoholic fatty liver disease (NAFLD) that can progress to liver cirrhosis, liver failure and hepatocellular carcinoma. It is the second leading cause of liver transplant in the US. We aim to investigate the prevalence, demographics and risk factors NASH patients in the US.

PATIENTS AND METHODS

We used a large database (Explorys IBM) that aggregates electronic health records from 26 nationwide healthcare systems. We identified adults with NASH between 2010-2020. Demographics including age, gender and race were collected. NASH risk factors including Diabetes Millets (DM), Hyperlipidemia (HLD), Hypertension (HTN) and Obesity were also collected. Cochran-Armitage test was used to assess the statistical significance of year-by-year trend. Univariable and multivariable logistic regression were used to estimate the odds ratio (OR) of risk factors.

RESULTS

NASH annual prevalence rate increased from 1.51% in 2010 to 2.79% in 2020 (p < 0.0001). The proportion of patients with NASH by gender was 54.1% female vs 45.9% male (OR 1.04 [0.91-1.11]). Caucasian had higher odds of NASH than non-Caucasian (OR 1.42 [1.31-1.54]). NASH is strongly associated with DM and obesity (OR 18.61 [17.35-19.94]) and (OR 20.97 [17.87-23.21]), respectively. Other components of metabolic syndrome were associated with NASH to a lesser degree; HTN (OR 3.24 [3.20-3.28]) and HLD (OR 4.93 [4.85-4.01]).

CONCLUSION

The prevalence of NASH has significantly increased in the US in the last decade. This is likely related to the increased prevalence of risk factors as well as increased awareness of the disease.

Essential amino acid enriched meal replacement improves body composition and physical function in obese older adults: A randomized controlled trial

BACKGROUND

Older adults are threatened by the risk of muscle atrophy and excess accumulation of adipose tissue. The objective of this study was to determine whether an essential amino acid enriched meal replacement would reduce excess fat and foster skeletal muscle retention, potentially improving physical function in this cohort.

METHODS

Using a double blind, randomized controlled trial, we compared the influence of an experimental meal replacement enriched with essential amino acids (EMR) to a commercially available, widely used meal replacement (Optifast®) provided once/day (q.d.) for four weeks on body composition, skeletal muscle and physical function in obese older participants. Twenty-eight individuals completed either EMR (n = 13) or Optifast® (n = 15) supplementation protocols. Measurements of body composition, thigh skeletal muscle cross-sectional area (CSA), blood panels, intrahepatic lipid, and physical function were completed pre- and post-supplementation.

RESULTS

Body fat mass, visceral fat mass and volume, and intrahepatic lipid were reduced with EMR but not with Optifast®. Thigh muscle CSA increased (Δ 2.4 ± 3.0 cm²) with EMR but not Optifast® (Δ -1.8 ± 6.0 cm²). There was a significant increase in the distance covered during the 6-min walk test with EMR (Δ 23 ± 27 m) but no change in Optifast® (Δ 11 ± 37 m).

CONCLUSIONS

Beneficial alterations in fat and muscle support the use of EMR-based meal replacements in obese older adults.

CLINICAL TRIAL REGISTRATION

ISRCTN registry under Reference Number ISRCTN15814848.

Evaluating Outcomes Related to Donor and Recipient Metabolic Environment: Macrosteatotic Allografts and Nonalcoholic Steatohepatitis

The increasing prevalence of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) affects both recipient and donor populations in liver transplantation. Presently, it is unclear whether transplantation of macrosteatotic allografts is affected by the metabolic milieu of liver transplant recipients. This study investigates fatty liver disease at the intersection of donor and recipient. A retrospective review of the Organ Procurement and Transplantation database identified 5167 NASH and 26,289 non-NASH transplant recipients who received transplants from January 1, 2004, to June 12, 2020. A total of 12,569 donors had allografts with no macrosteatosis (<5%), 16,140 had mild macrosteatosis (5%-29%), and 2747 had moderate to severe macrosteatosis (≥30%). Comparing recipients with NASH to propensity score-matched (PSM) recipients without NASH demonstrated noninferior graft and patient survival up to 10 years in patients with NASH. Similar trends were observed in subgroup analyses of transplants within each strata of allograft macrosteatosis. Assessing allograft macrosteatosis specifically in the NASH population demonstrated that allografts with ≥30% macrosteatosis were associated with reduced early graft survival (30 days, 93.32% versus 96.54% [P = 0.02]; 1 year, 84.53% versus 88.99% [P = 0.05]) compared with PSM grafts with <30% macrosteatosis. Long-term graft survival at 5 and 10 years, however, was similar. The use of carefully selected macrosteatotic allografts can be successful in both recipients with NASH and recipients without NASH. The metabolic environment of patients with NASH does not appear to adversely affect outcomes with regard to the allograft when controlled for numerous confounders. It is, however, important to remain cognizant of the potential for high-risk macrosteatotic allografts to negatively affect outcomes.

High-priority liver transplantation and simultaneous sleeve gastrectomy in MELD 32 end-stage liver disease: a case report with long-term follow-up

BACKGROUND

Morbid obesity is a worldwide epidemic closely linked to Non-Alcoholic Fatty Liver Disease (NAFLD), an ever more relevant indication for Liver Transplantation (LT). Obesity affects an increasing number of LT recipients, but the ideal management of these patients remain unclear. Bariatric surgery (BS) in LT setting is challenging but feasible, although the debate is still open about the best timing of bariatric surgery. Herein we report a case of high-priority LT and simultaneous sleeve gastrectomy (SG) in an obese young adult.

CASE REPORT

A 45 years old man with morbid obesity (BMI 46 kg/m²) and severe NAFLD-related end-stage liver disease (ESLD) underwent simultaneous LT and sleeve gastrectomy (SG) in an emergency setting, due to a MELD score of 32. He had substantial weight loss during long-term follow-up and enjoyed resolution of diabetes and hypertension. At 4 years follow-up, he has normal allograft function with appropriate immunosuppressant blood levels and no ultrasound evidence of steatosis.

CONCLUSION

In selected patients, combined LT and SG present several advantages in terms of transplant outcomes, weight loss and resolution of obesity-related comorbidities. In addition, it can be performed in the high-priority setting in case of severe ESLD with good results in the short- and long-term.

Metabolic associated fatty liver disease and acute-on-chronic liver failure: common themes for common problems

Metabolic associated fatty liver disease (MAFLD) affects 20-30% of the worldwide population and is becoming the most common cause of chronic liver disease, cirrhosis and hepatocellular carcinoma (HCC). MAFLD is the hepatic expression of metabolic dysfunction correlated with a variety of metabolic comorbidities including obesity, dyslipidemia, hypertension and type 2 diabetes (T2DM). Obesity, altered gut permeability, chronic inflammation and dysbiosis related to MAFLD might predispose patients with cirrhosis to the development of acute-on-chronic liver failure (ACLF); however, this relationship remains unclear. ACLF is a syndrome with high short-term mortality, presenting with acute hepatic decompensation associated with organ failures in patients with underlying chronic liver disease with or without an identifiable precipitating event. While this syndrome can occur in any patient with cirrhosis, the increasing prevalence of cirrhosis due to MAFLD is of great concern because, in a recent analysis, MAFLD was the fastest rising cause of cirrhosis associated with ACLF among patients listed for LT in the US. In this review, we will discuss the current knowledge on MAFLD and the development of ACLF.

Non-alcoholic fatty liver disease and obesity among adult donors are major challenges to living donor liver transplantation: A single-centre experience

OBJECTIVES

Obesity and non-alcoholic fatty liver disease (NAFLD) are rampant in South East Asia. There is paucity of data exploring its' impact on donor suitability for living donor liver transplantation (LDLT). We aimed to describe and examine the factors related to non-utilization of potential donors in our LDLT programme.

METHODS

This is an analysis of prospectively collected data on potential donors for an adult LDLT programme, between January 2017 and December 2019.

RESULTS

Fifty-five donors for 33 potential recipients were evaluated. The mean age was 31.6 ± 8.5 years, 52.7% were female and the ethnic divisions were: Chinese (50.9%), Indian (25.5%) and Malay (23.6%). The mean body mass index (BMI) among potential donors was 25.1 ± 4.0 kg/m²; 25.5% of donors had normal BMI, 23.6% were overweight and 50.9% were obese. Using the CAP modality of Fibroscan®, we identified the following grades of hepatic steatosis: 36.6% S0, 19.5% S1, 2.4% S2 and 41.5% S3. The non-utilization rate of our donors was 74.5% (41/55) and the main reasons were significant hepatic steatosis and/or obesity. Compared to suitable donors, unsuitable donors had significantly greater mean BMI, mean CAP scores, higher rates of dyslipidaemia and NAFLD.

CONCLUSION

NAFLD and obesity represent major challenges to an emerging LDLT programme in Malaysia.

Trends in indications and outcomes of liver transplantation in Canada: A multicenter retrospective study

The liver transplantation (LT) landscape is continuously evolving. We sought to evaluate trends in indications for LT in Canada and the impact of primary liver disease on post-LT outcomes using a national transplant registry. Adult patients who underwent a primary LT between 2000 and 2018 were retrospectively identified in the Canadian Organ Replacement Registry. Outcomes included post-LT patient and graft survival. A total of 5,722 LTs were identified. The number of LT per year increased from 251 in 2000 to 349 in 2018. The proportion of patients transplanted for HCV decreased from 31.5% in 2000 to 3.4% in 2018. In contrast, the percentage of transplants for HCC increased from 2.3% in 2000 to 32.4% in 2018, and those performed for NASH increased from 0.4% in 2005 to 12.6% in 2018. Year of transplant (per 1 year) was protective for both patient (HR:0.96,95%CI:0.94-0.97; P < 0.001) and graft survival (HR:0.97, 95%CI: 0.96-0.99; P = 0.001). Post-LT outcomes have improved over time in this nationwide analysis spanning 18 years. Moreover, trends in the indications for LT have changed, with HCC becoming the leading etiology. The decrease in the proportion of HCV patients and increase in those with NASH has implications on the evolving management of LT patients.

Non-alcoholic fatty liver disease: a review of epidemiology, risk factors, diagnosis and management

Due to the rising prevalence of obesity and type II diabetes mellitus, non-alcoholic fatty liver disease is becoming the leading cause of chronic liver disease in the Western world. In some patients, simple steatosis can result in non-alcoholic steatohepatitis which over time can lead to liver cirrhosis and its associated sequelae, including hepatocellular carcinoma. Early identification and management of patients at risk with intensive dietary and lifestyle modification are essential to prevent the development of advanced liver disease and its complications. In this review, we will discuss the epidemiology of non-alcoholic fatty liver disease, pathogenesis, diagnosis, management and surveillance strategies to offset the morbidity and mortality of this disease, as well as liver and non-liver-related complications.

Noninvasive markers of liver steatosis and fibrosis after liver transplantation - Where do we stand?

In the last two decades, advances in immunosuppressive regimens have led to fewer complications of acute rejection crisis and consequently improved short-term graft and patient survival. In parallel with this great success, long-term post-transplantation complications have become a focus of interest of doctors engaged in transplant medicine. Metabolic syndrome (MetS) and its individual components, namely, obesity, dyslipidemia, diabetes, and hypertension, often develop in the post-transplant setting and are associated with immuno-suppressive therapy. Nonalcoholic fatty liver disease (NAFLD) is closely related to MetS and its individual components and is the liver manifestation of MetS. Therefore, it is not surprising that MetS and its individual components are associated with recurrent or "de novo" NAFLD after liver transplantation (LT). Fibrosis of the graft is one of the main determinants of overall morbidity and mortality in the post-LT period. In the assessment of post-LT steatosis and fibrosis, we have biochemical markers, imaging methods and liver biopsy. Because of the significant economic burden of post-LT steatosis and fibrosis and its potential consequences, there is an unmet need for noninvasive methods that are efficient and cost-effective. Biochemical scores can overestimate fibrosis and are not a good method for fibrosis evaluation in liver transplant recipients due to frequent post-LT thrombocytopenia. Transient elastography with controlled attenuation parameter is a promising noninvasive method for steatosis and fibrosis. In this review, we will specifically focus on the evaluation of steatosis and fibrosis in the post-LT setting in the context of de novo or recurrent NAFLD.

Bariatric Surgery Outcomes in Patients with Previous Organ Transplant: Scoping Review and Analysis of the MBSAQIP

BACKGROUND

Obesity is a major risk factor for transplant. Laparoscopic bariatric surgery (LBS) offers transplant patient benefits including improved comorbidities, graft function, and longevity. We completed a scoping review and analyzed the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) to determine the risk-benefit profile of LBS after transplant. We also compared laparoscopic sleeve gastrectomy (LSG) to laparoscopic Roux-en-Y gastric bypass (LRYGB) following transplant.

METHODS

Univariate analysis determined between group differences with subgroup analysis comparing LSG versus LRYGB in transplant patients. Multivariable analysis assessed whether prior transplant was independently associated with major complications or mortality.

RESULTS

A total of 469 (0.1%) patients had previous transplant and had more comorbidities and more often underwent LSG. Operative time (93.9 min vs 83 min, p < 0.001) and length of stay were longer. Major complications were threefold higher in patients with a transplant history (9.6% vs 3.2%; p < 0.001. Previous transplant was the second greatest independent predictor for major complication (OR 2.14 [1.54-2.98], p = < 0.001) but was not predictive of death (OR 1.06 [0.14-8.13] p = 0.956). Amongst transplant patients, LRYGB demonstrated higher rates of leak (n = 1), VTE, AKI, unplanned intubation, and readmission.

CONCLUSIONS

The 30-day complication rate from LBS is three times higher amongst patients with a transplant. LSG is likely the best surgical approach. Despite risks, post-transplant patients incur important benefits from LBS. Surgeons must be aware of this risk-benefit profile when determining LBS candidacy.

Transplant Outcomes in Older Patients With Nonalcoholic Steatohepatitis Compared to Alcohol-related Liver Disease and Hepatitis C

BACKGROUND

Patients with nonalcoholic steatohepatitis (NASH) are waitlisted at older ages than individuals with other liver diseases, but the effect of age on liver transplantation (LT) outcomes in this population and whether it differs from other etiologies is not known. We aimed to evaluate the impact of age on LT outcomes in NASH.

METHODS

The United Network for Organ Sharing database was used to identify adults with NASH, hepatitis C virus (HCV) infection, and alcohol-related liver disease (ALD) listed for LT during 2004-2017. Patients were split into age groups (18-49, 50-54, 55-59, 60-64, 65-69, ≥70), and their outcomes were compared.

RESULTS

From 2004 to 2017, 14 197 adults with NASH were waitlisted, and the proportion ≥65 increased from 15.8% to 28.9%. NASH patients ages 65-69 had an increased risk of waitlist and posttransplant mortality compared to younger groups, whereas the outcomes in ages 60-64 and 55-59 were similar. The outcomes of individuals with NASH were similar to patients of the same age group with ALD or HCV. Functional status and dialysis were predictors of posttransplant mortality in individuals ≥65 with NASH, and cardiovascular disease was the leading cause of death.

CONCLUSIONS

Older NASH patients (≥65) have an increased risk of waitlist and posttransplant mortality compared to younger individuals, although outcomes were similar to patients with ALD or HCV of corresponding age. These individuals should be carefully evaluated prior to LT, considering their functional status, renal function, and cardiovascular risk. Further studies are needed to optimize outcomes in this growing population of transplant candidates.

Liver transplantation and aging

An increase in the average life expectancy, paralleled by a demographic shift in the population with end-stage liver disease lies behind the rising demand for liver transplantation (LT) among the elderly. Some of the most common indications for LT including hepatocellular carcinoma, alcohol-related liver disease, chronic hepatitis C and non-alcoholic fatty liver disease tend to affect older patients. Transplant professionals are faced with an increasing demand for LT among elderly patients in an age of organ shortage and it is important that risk and benefits are carefully weighed in order to achieve the optimum use of precious liver grafts.

Mechanisms of nonalcoholic fatty liver disease and implications for surgery

Background

Nonalcoholic fatty liver disease (NAFLD) has become the most common form of chronic liver disease in both adults and children worldwide. Understanding the pathogenic mechanisms behind NAFLD provides the basis for identifying risk factors, such as metabolic syndrome, pancreatoduodenectomy, and host genetics, that lead to the onset and progression of the disease. The progression from steatosis to more severe forms, such as steatohepatitis, fibrosis, and cirrhosis, leads to an increased number of liver and non-liver complications.

Purpose

NAFLD-associated end-stage liver disease (ESLD) and hepatocellular carcinoma (HCC) often require surgery as the only curative treatment. In particular, the presence of NAFLD together with the coexisting metabolic comorbidities that usually occur in these patients requires careful preoperative diagnosis and peri-/postoperative management. Bariatric surgery, liver resection, and liver transplantation (LT) have shown favorable results for weight loss, HCC, and ESLD in patients with NAFLD. The LT demand and the increasing spread of NAFLD in the donor pool reinforce the already existing lack of donor organs.

Conclusion

In this review, we will discuss the diverse mechanisms underlying NAFLD, its implications for surgery, and the challenges for patient management.

Liver transplantation and cardiac illness: Current evidences and future directions

Contraindications to liver transplantation are gradually narrowing. Cardiac illness and chronic liver disease may manifest independently or may be superimposed on each other due to shared pathophysiology. Cardiac surgery involving the cardiopulmonary bypass in patients with Child-Pugh Class C liver disease is associated with a high risk of perioperative morbidity and mortality. Liver transplantation involves hemodynamic perturbations, volume shifts, coagulation abnormalities, electrolyte disturbances, and hypothermia, which may prove fatal in patients with cardiac illness depending upon the severity. Additionally, cardiovascular complications are the major cause of adverse postoperative outcomes after liver transplantation even in the absence of cardiac pathologies. Clinical decision-making has remained an unsettled issue in these clinical scenarios. The absence of randomized clinical studies has further crippled our endeavours for a consensus on the management of patients with end-stage liver disease with cardiac illness. This review seeks to address this complex clinical setting by gathering information from published literature. The management algorithm in this review may facilitate clinical decision making and augur future research.

The decreasing predictive power of MELD in an era of changing etiology of liver disease

The field of liver transplantation has shifted considerably in the MELD era, including changing allocation, immunosuppression, and liver failure etiologies, as well as better supportive therapies. Our aim was to evaluate the predictive accuracy of the MELD score over time. The United Network for Organ Sharing provided de-identified data on 120 156 patients listed for liver transplant from 2002-2016. The ability of the MELD score to predict 90-day mortality was evaluated by a concordance (C-) statistic and corroborated with competing risk analysis. The MELD score's concordance with 90-day mortality has downtrended from 0.80 in 2003 to 0.70 in 2015. While lab MELD scores at listing and transplant climbed in that interval, score at waitlist death remained steady near 35. Listing age increased from 50 to 54 years. HCV-positive status at listing dropped from 33 to 17%. The concordance of MELD and mortality does not differ with age (>60 = 0.73, <60 = 0.74), but is lower in diseases that are increasing most rapidly-alcoholic liver disease and non-alcoholic fatty liver disease-and higher in those that are declining, particularly in HCV-positive patients (HCV positive = 0.77; negative = 0.73). While MELD still predicts mortality, its accuracy has decreased; changing etiology of disease may contribute.

The Perception of Medical Students at King Abdulaziz University Hospital Regarding the Liver Transplant Allocation System

Background: The benefit of liver transplantation is not only to increase the patient’s lifetime but also for persistent relief of pain and anxiety. Shortage of the organ is the main hindrance of transplantation around the world, leading authorities to pass a general law for the reasonable distribution of organs and come up with the Model for End-Stage Liver Disease (MELD) system which scores the severity of liver disease and risk of mortality in order to detect the mechanism of allocation. 

Objective: This study aims to assess medical students’ perception of the liver transplant and allocation system.

Methods: A cross-sectional survey was carried out among 402 medical students at King Abdulaziz University in Jeddah, Saudi Arabia.

Results: The majority of the medical students (84.4%) believed that a successful liver transplant improves both lifetime and quality of life. Most of the students also saw that the minimum survival rate should be five years after transplantation and that the patient should recover to be at least ambulatory, even if restricted by strenuous physical activity. When asked whether urgency or prospect of success defined a successful transplant, most of the students who chose urgency were preclinical (50.7%), while the prospect of success was the dominant answer chosen by students in their clinical years of study (66.1%).

Conclusion: The criteria determining the success of a liver transplant include a gain in both lifetime and quality of life. The majority of respondents wanted the capacity to benefit to be considered in the liver allocation system.

Potential Therapeutic Application of Estrogen in Gender Disparity of Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) caused by fat accumulation in the liver is globally the most common cause of chronic liver disease. Simple steatosis can progress to nonalcoholic steatohepatitis (NASH), a more severe form of NAFLD. The most potent driver for NASH is hepatocyte death induced by lipotoxicity, which triggers inflammation and fibrosis, leading to cirrhosis and/or liver cancer. Despite the significant burden of NAFLD, there is no therapy for NAFLD/NASH. Accumulating evidence indicates gender-related NAFLD progression. A higher incidence of NAFLD is found in men and postmenopausal women than premenopausal women, and the experimental results, showing protective actions of estradiol in liver diseases, suggest that estrogen, as the main female hormone, is associated with the progression of NAFLD/NASH. However, the mechanism explaining the functions of estrogen in NAFLD remains unclear because of the lack of reliable animal models for NASH, the imbalance between the sexes in animal experiments, and subsequent insufficient results. Herein, we reviewed the pathogenesis of NAFLD/NASH focused on gender and proposed a feasible association of estradiol with NAFLD/NASH based on the findings reported thus far. This review would help to expand our knowledge of the gender differences in NAFLD and for developing gender-based treatment strategies for NAFLD/NASH.

Inflammasome-Mediated Inflammation in Liver Ischemia-Reperfusion Injury

Ischemia-reperfusion injury is an important cause of liver damage occurring during surgical procedures including hepatic resection and liver transplantation, and represents the main underlying cause of graft dysfunction and liver failure post-transplantation. To date, ischemia-reperfusion injury is an unsolved problem in clinical practice. In this context, inflammasome activation, recently described during ischemia-reperfusion injury, might be a potential therapeutic target to mitigate the clinical problems associated with liver transplantation and hepatic resections. The present review aims to summarize the current knowledge in inflammasome-mediated inflammation, describing the experimental models used to understand the molecular mechanisms of inflammasome in liver ischemia-reperfusion injury. In addition, a clear distinction between steatotic and non-steatotic livers and between warm and cold ischemia-reperfusion injury will be discussed. Finally, the most updated therapeutic strategies, as well as some of the scientific controversies in the field will be described. Such information may be useful to guide the design of better experimental models, as well as the effective therapeutic strategies in liver surgery and transplantation that can succeed in achieving its clinical application.

Nonalcoholic steatohepatitis: the new frontier for liver transplantation

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is a growing cause of chronic liver disease globally and nonalcoholic steatohepatitis is projected to become the most common indication for liver transplantation. The purpose of this review is to highlight key issues surrounding NAFLD as an indication for liver transplantation, including its increasing prevalence, outcomes related to liver transplantation, development of post liver transplant NAFLD and NAFLD in the liver donor pool.

RECENT FINDINGS

With the advent of direct-acting antiviral therapies, the proportion of patients on the liver transplant list or undergoing liver transplant for chronic hepatitis C infection is steadily decreasing. In contrast, the number transplants performed for NAFLD is increasing. By 2030, it is estimated that the incidence of decompensated cirrhosis and hepatocellular carcinoma will increase by 168 and 137%, respectively, and the number of deaths will increase by 178%.

SUMMARY

Liver transplantation cures cirrhosis but does not treat the underlying metabolic disease associated with NAFLD. Thus, strategies to control comorbidities in patients with NAFLD prior to transplant are needed to decrease waitlist mortality and the recurrence of NAFLD after liver transplant. NAFLD in the donor pool is also a growing concern. Strategies to minimize steatosis and expand the number of donors are critical to meet the growing demand for liver transplantation.

Use of Steatotic Grafts in Liver Transplantation: Current Status

In the field of liver transplantation, the demand for adequate allografts greatly exceeds the supply. Therefore, expanding the donor pool to match the growing demand is mandatory. The present review summarizes current knowledge of the pathophysiology of ischemia/reperfusion injury in steatotic grafts, together with recent pharmacological approaches aimed at maximizing the utilization of these livers for transplantation. We also describe the preclinical models currently available to understand the molecular mechanisms controlling graft viability in this specific type of donor, critically discussing the heterogeneity in animal models, surgical methodology, and therapeutic interventions. This lack of common approaches and interventions makes it difficult to establish the pathways involved and the relevance of isolated discoveries, as well as their transferability to clinical practice. Finally, we discuss how new therapeutic strategies developed from experimental studies are promising but that further studies are warranted to translate them to the bedside.

Low fat but not soy protein isolate was an effective intervention to reduce nonalcoholic fatty liver disease progression in C57BL/6J mice: monitored by a novel quantitative ultrasound (QUS) method

Untreated nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) lead to irreversible liver damage. We hypothesized that a low-fat diet (LFD) or a high-fat diet (HFD) with soy protein isolate (SPI) would be an effective intervention to halt or reverse NAFLD progression. To test these hypotheses, we conducted 2 studies. In the first study, we fed an HFD to 7-week-old C57BL/6J mice to induce NAFLD compared to an LFD (control). Hepatic steatosis was monitored by quantitative ultrasound (QUS) scans (in vivo and ex vivo). Animals were euthanized after 0, 2, 4, and 6 weeks of feeding. In the second study, 7-week-old mice were randomized onto an LFD or HFD with SPI intervention after 4 weeks of feeding HFD. Animals from each group were scanned with QUS and euthanized after 4, 9, and 12 weeks of feeding. Animals fed the HFD developed NAFLD (100%) and NASH (80%) characterized by increased liver weight, lipid accumulation, and histological scores for inflammation by 4 weeks in the first study. In the second study, the LFD ameliorated this NAFLD phenotype after 5 weeks of feeding; however, the SPI intervention failed to significantly attenuate NAFLD. QUS parameters were significantly increased with the HFDs (P < .05) and steatosis grade (P < .05) and were positively correlated with hepatic lipid concentrations. In conclusion, dietary modification may be effective at reversing NAFLD and NASH at early stages. Furthermore, QUS may become a valuable tool to track hepatic steatosis. Additional studies are needed to further evaluate the effectiveness of these interventions.

The Mexican consensus on nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) affects nearly one third of the population worldwide. Mexico is one of the countries whose population has several risk factors for the disease and its prevalence could surpass 50%. If immediate action is not taken to counteract what is now considered a national health problem, the medium-term panorama will be very bleak. This serious situation prompted the Asociación Mexicana de Gastroenterología and the Asociación Mexicana de Hepatología to produce the Mexican Consensus on Fatty Liver Disease. It is an up-to-date and detailed review of the epidemiology, pathophysiology, clinical forms, diagnosis, and treatment of the disease, whose aim is to provide the Mexican physician with a useful tool for the prevention and management of nonalcoholic fatty liver disease.

Nonalcoholic Fatty Liver Disease: Epidemiology, Liver Transplantation Trends and Outcomes, and Risk of Recurrent Disease in the Graft

In parallel with the rising prevalence of metabolic syndrome globally, nonalcoholic fatty liver (NAFL) disease is the most common chronic liver disease in Western countries and nonalcoholic steatohepatitis (NASH) has become increasingly associated with hepatocellular carcinoma. Recent studies have identified NASH as the most rapidly growing indication for liver transplantation (LT). As a hepatic manifestation of the metabolic syndrome, NAFL disease can be histologically divided into NAFL and NASH. NAFL is considered a benign condition, with histological changes of hepatocyte steatosis but without evidence of hepatocellular injury or fibrosis. This is distinct from NASH, which is characterized by hepatocyte ballooning and inflammation, and which can progress to fibrosis and cirrhosis, hepatocellular carcinoma, and liver failure. As for any other end-stage liver disease, LT is a curative option for NASH after the onset of decompensated cirrhosis or hepatocellular carcinoma. Although some studies have suggested increased rates of sepsis and cardiovascular complications in the immediate postoperative period, the long-term posttransplant survival of NASH cases is similar to other indications for LT. Recurrence of NAFL following LT is common and can be challenging, although recurrence rates of NASH are lower. The persistence or progression of metabolic syndrome components after LT are likely responsible for NASH recurrence in transplanted liver. Therefore, while maintaining access to LT is important, concerted effort to address the modifiable risk factors and develop effective screening strategies to identify early stages of disease are paramount to effectively tackle this growing epidemic.

Liver Transplantation (LT) for Cryptogenic Cirrhosis (CC) and Nonalcoholic Steatohepatitis (NASH) Cirrhosis: Data from the Scientific Registry of Transplant Recipients (SRTR): 1994 to 2016

Nonalcoholic steatohepatitis (NASH)-related cirrhosis and cryptogenic cirrhosis (CC) have become leading indications for liver transplantation (LT) in the US. Our aim was to compare the trends, clinical presentation, and outcomes for transplant candidates with NASH and CC.The Scientific Registry of Transplant Recipients (1994-2016) was used to select adult LT candidates and recipients with primary diagnoses of NASH and CC without hepatocellular carcinoma.Two lakh twenty-three thousand three hundred ninety-one LT candidates were listed between 1994 and 2016. Of these, 16,214 (7.3%) were listed for CC and 11,598 (5.2%) for NASH. Before 2004, NASH was seldom coded for an indication for LT, but became more common after 2009. Averaged across the study period, CC candidates compared with NASH candidates were younger and had fewer conditions of metabolic syndrome (MS). CC patients were more likely to have MS components in comparison to candidates with other chronic liver diseases (CLDs) (all P < .0001). For most of the study period, patients with CC or NASH were similarly more likely to be taken off the list due to deterioration or death, with to patients with other CLDs. Post-LT data were available for 14,052 transplant recipients with NASH or CC. With the exception of post-transplant diabetes, the outcomes of patients transplanted for CC and NASH were similar to those of other CLD patients.Number of LT due to CC and NASH cirrhosis is increasing. In the past decade, there is a shift from LT listing diagnosis from CC to NASH potentially related to increased awareness about NASH in transplant centers in the US.

Nonalcoholic fatty liver disease and liver transplantation - Where do we stand?

Nonalcoholic fatty liver disease/nonalcoholic steatohepatitis (NAFLD/NASH) is a challenging and multisystem disease that has a high socioeconomic impact. NAFLD/NASH is a main cause of macrovesicular steatosis and has multiple impacts on liver transplantation (LT), on patients on the waiting list for transplant, on post-transplant setting as well as on organ donors. Current data indicate new trends in the area of chronic liver disease. Due to the increased incidence of metabolic syndrome (MetS) and its components, NASH cirrhosis and hepatocellular carcinoma caused by NASH will soon become a major indication for LT. Furthermore, due to an increasing incidence of MetS and, consequently, NAFLD, there will be more steatotic donor livers and less high quality organs available for LT, in addition to a lack of available liver allografts. Patients who have NASH and are candidates for LT have multiple comorbidities and are unique LT candidates. Finally, we discuss long-term grafts and patient survival after LT, the recurrence of NASH and NASH appearing de novo after transplantation. In addition, we suggest topics and areas that require more research for improving the health care of this increasing patient population.

Clinical relevance of liver histopathology and different histological classifications of NASH in adults

Nonalcoholic fatty liver disease (NAFLD) encompasses simple steatosis and steatohepatitis (NASH) with or without fibrosis/cirrhosis and hepatocellular carcinoma. NAFLD occurs epidemically in most areas of the world, contributes to cardiovascular events and liver-related mortality and therefore exacts a major economic toll. Areas covered: Here we summarize what clinicians should know about NAFLD histopathology in adults. We report on the individual histological features and scoring systems of NAFLD: the NAFLD activity score (NAS) introduced by the NASH-Clinical Research Network, the 'Fatty Liver Inhibition of Progression' algorithm and Steatosis, Activity, and Fibrosis (SAF) score. Pros and cons of histological classifications in NASH are discussed. Special emphasis is given to liver histopathology in some high-risk patient groups, such as those with severe obesity and type 2 diabetes. Moreover, we also examine the relationship between liver histopathology and clinical features, and the impact of liver histopathology on the long-term prognosis of NAFLD. Finally, we propose an integrated diagnostic approach which utilizes both non-invasive tools and liver biopsy in those individual patients with suspected NAFLD. Expert commentary: Based on expert opinions, we conclude with a research agenda on NAFLD which focuses on the most burning topics to be addressed over the next five years.

Management of portal hypertension before and after liver transplantation

Orthotopic liver transplantation (OLT) represents a curative treatment option for end-stage liver disease (ESLD). Although epidemiology of ESLD has recently changed due to the rising prevalence of nonalcoholic fatty liver disease and the decreased burden of hepatitis C virus infections due to highly effective antiviral regimens, the management of portal hypertension (PHT) remains a clinical challenge in the pre- and post-OLT setting. The measurement of the hepatic venous pressure gradient represents the most reliable but invasive tool for assessment of the severity of PHT. Although novel liver ultrasound and magnetic resonance-based elastography methods have been developed, their value to screen for liver fibrosis and PHT in transplanted patients remains to be established. Nonselective beta-blockers represent the cornerstone of medical treatment of PHT, but more studies on their effects on clinical endpoints after OLT are needed. Statins are widely used to treat hyperlipidemia, which is a common condition after OLT. Although a growing body of evidence suggests that statins decrease portal pressure and PHT-related complications in ESLD, studies on potential benefits of statins after OLT are lacking. Finally, transjugular intrahepatic portosystemic shunts (TIPS) are effective in decreasing PHT and seem to decrease mortality on the OLT waiting list. Moreover, TIPS does not have an impact on liver function nor complicate the transplant surgical procedures. TIPS may also be used after OLT, but the evidence is limited. In conclusion, whereas the management of PHT in patients with ESLD is based on strong evidence, further data on the value of noninvasive monitoring tools as well as on medical and invasive treatment options in the post-OLT setting are needed to improve management strategies in patients with recurrent PHT after liver transplantation. Liver Transplantation 24 112-121 2018 AASLD.

Outcome of liver transplantation in patients with prior bariatric surgery

Nonalcoholic fatty liver disease is becoming the leading cause of disease resulting in liver transplantation (LT). As a result of this trend, more LT candidates are presenting with prior history of bariatric surgery (BS). Over the last decade, 960 patients underwent LT at our institution; 11 (1.1%) had prior BS. The most common type of BS was Roux-en-Y gastric bypass (n = 9) with 1 sleeve gastrectomy and 1 jejunoileal bypass. A total of 9 patients underwent LT alone, and 2 underwent simultaneous liver-kidney transplantation. The most common indication for LT was nonalcoholic steatohepatitis (n = 10) with 5 having additional diagnosis of alcoholic liver disease. The 30-day reoperation rate was 36.4% (n = 4); indications were bile duct repair (n = 3) and wound repair (n = 1). In the first 6 months after LT, biliary complications were seen in 54.5% (n = 6) of the patients. Both patient and graft survival rates at 1 and 2 years were 81.8% (n = 9) and 72.7% (n = 8), respectively. A total of 8 patients (72.7%) had indications for liver biopsy after LT; significant macrovesicular steatosis was found in 2 (18.2%). In patients with a history of alcohol consumption, 2 (40.0%) relapsed after LT. Two patients (18.2%) had a history of diet-controlled diabetes before LT; 1 of these patients became insulin dependent after LT. Mean body mass index (BMI) at LT was 31.0 ± 5.7 kg/m² . Mean BMI at 1, 6, and 12 months after LT was 28.3 ± 5.8, 28.0 ± 3.2, and 31.0 ± 6.6 kg/m² , respectively. Mean preoperative albumin was 2.6 ± 0.6 mg/dL. Patients showed improvement in albumin after LT, with mean albumin of 2.7 ± 0.6 and 3.2 ± 0.5 mg/dL at 1 and 3 months, respectively. The liver profile was stable after LT, with mean aspartate aminotransferase of 32.9 ± 18.4 and 26.6 ± 19.8 IU/L and alanine aminotransferase of 28.0 ± 17.5 and 30.2 ± 17.0 IU/L at 6 and 12 months, respectively. In conclusion, outcomes of LT patients with prior BS are comparable with other transplant recipients with regards to patient and graft survival and post-LT complication rates. Liver Transplantation 23 1415-1421 2017 AASLD.

Cirrhotic cardiomyopathy: Implications for liver transplantation

The majority of patients on a waiting list for liver transplantation have end-stage liver disease. Because of the marked peripheral vasodilatation of end-stage cirrhosis that masks a latent myocardial dysfunction, cardiac abnormalities in the resting state are usually subclinical and escape the attention of physicians. However, when challenged, the systolic and diastolic contractile responses are attenuated. In addition to these contractile abnormalities, morphological changes, such as enlargement or hypertrophy of cardiac chambers, and electrophysiological repolarization changes, including a prolonged QT interval, can be observed. The constellation of these cardiac abnormalities is termed cirrhotic cardiomyopathy. Liver transplantation induces significant cardiovascular stress. Clamping of the inferior vena cava and portal vein, hemorrhage and blood/volume infusion, and ischemia/reperfusion all cause hemodynamic fluctuation. The changing cardiac preload and afterload status increases the cardiac workload, and thus, the previously subclinical ventricular dysfunction may manifest as overt heart failure during the operative and perioperative periods. Cardiac dysfunction contributes to morbidity and mortality associated with liver transplantation. Cardiovascular events are the third leading cause of death in liver recipients. However, because liver transplantation is the only definitive treatment for end-stage liver failure and also appears to reverse cardiac abnormalities, it is important to understand the challenges of the heart in liver transplantation. This review focuses on cardiac status before, during, and after liver transplantation. Liver Transplantation 23 826-835 2017 AASLD.

Cardiovascular assessment in liver transplant for non-alcoholic steatohepatitis patients: What we do, what we should do

Non-alcoholic fatty liver disease (NAFLD) is increasing considerably due to the current lifestyle, which means that it is becoming one of the main indications for liver transplantation. On the other hand, there is a strong association between NAFLD and cardiovascular disease. This has been evidenced in many studies revealing a higher presence of carotid plaques or carotid intima-media thickness, leading to cardiovascular events and, ultimately, mortality. According to the liver transplant guidelines, screening for heart disease in transplant candidates should be performed by electrocardiogram and transthoracic echocardiography while a stress echocardiogram should be reserved for those with more than two cardiovascular risk factors or greater than 50 years old. However, there are no specific recommendations in NAFLD patients requiring a liver transplantation, despite its well-known cardiovascular risk association. Many studies have shown that these patients probably require a more exhaustive assessment and a global approach including other specialists such as cardiologists or nutritionists. Also, the incidence of cardiovascular disease is also increased in NAFLD patients in the post-transplantation period in comparison with other etiologies, because of the pre-existent risk factors together with the immunosuppressive therapy. Therefore, an early intervention on the lifestyle and the individualized selection of the immunosuppressive regimen could lead to a modification of the cardiovascular risk factors in NAFLD patients requiring a liver transplantation.

Liver Transplantation and Bariatric Surgery: Best Approach

Obesity has become increasingly prevalent, and the number of obese patients in need of liver transplant is expected to continue to increase. In addition, liver disease due to nonalcoholic fatty liver disease is expected to become the leading cause of liver transplantation in the near future. However, obesity remains a relative contraindication in liver transplant. New strategies in managing this patient population are clearly needed. To this end, the authors review the current literature on the efficacy of bariatric surgery in the setting of liver transplantation in obese patients.

Bariatric Surgery and Liver Transplantation

Obesity is an important public health and medical concern in the United States. The rate of obesity has steadily risen for the past several decades. Obesity is associated with the development of nonalcoholic steatohepatitis, which is one of the leading indications for liver transplantation. After liver transplantation, recipients tend to gain weight and develop recurrent fatty liver. Over time, recurrent fatty liver may impact patient and graft survival. A bariatric surgical approach may be beneficial in select patients.

The role of extended criteria donors in liver transplantation for nonalcoholic steatohepatitis

BACKGROUND

Nonalcoholic steatohepatitis is expected to become the leading indication for liver transplantation. Use of extended criteria donors (ECD) may help with donor allocation in these patients. The objective of this study was to determine the use of ECDs in patients with nonalcoholic steatohepatitis undergoing liver transplantation to stimulate a liver-specific predictive model for ECD use.

METHODS

The United Network for Organ Sharing database was used to identify patients undergoing liver transplantation for nonalcoholic steatohepatitis (2002-2014). Cox hazards models were created using (1) United Network for Organ Sharing ECD criteria (based on kidney allocation), (2) individual donor characteristics (age, sex, race, cause of death, body mass index, cold ischemic time), and (3) the Kidney Donor Profile Index (KDPI) to examine the effect of ECDs on mortality and graft failure.

RESULTS

A total of 4,387 patients underwent liver transplantation for nonalcoholic steatohepatitis; 1,359 (30.9%) patients received an ECD. Transplantation with ECD livers had comparable patient survival (hazard ratio [HR] 1.06, 95% confidence interval [CI] 0.91-1.23) between donor types but an increased risk of graft failure (HR 1.18, 95% CI 1.03-1.36) compared to standard donors. Individual characteristics did not affect patient survival or graft failure. A 10% increase in KDPI was associated with a 28% increase in patient mortality (HR 1.28, 95% CI 1.02-1.60) and 45% increase in graft failure (HR 1.45, 95% CI 1.18-1.80).

CONCLUSION

Based on the current United Network for Organ Sharing definition, ECDs in nonalcoholic steatohepatitis were associated with similar overall survival but increased risk of graft failure. Given the shortage of organs, creation of an easily calculated, liver-specific model similar to the KDPI may help risk stratify patients and improve organ allocation.