De Novo and Recurrence of Nonalcoholic Steatohepatitis After Liver Transplantation

NASH After Liver Transplantation: Impact of Immunosuppression

Non-alcoholic fatty liver disease (NAFLD) has emerged as one of the common causes of cirrhosis and hepatocellular carcinoma (HCC) and is a leading indication for liver transplantation (LT). Patients with NAFLD-related cirrhosis and HCC are at high risk for the development of recurrent NAFLD after LT. NAFLD can also develop de novo post-transplantation in patients subjected to LT for other indications. Besides the pretransplant presence of various components of metabolic syndrome (MS) use of immunosuppressive agents in the post-LT setting forms one of the major drivers for the development of post-LT NAFLD. Individual components of conventional immunosuppressive regimens (corticosteroids, calcineurin inhibitors, and m-TOR inhibitors) are all implicated in the development of post-LT metabolic derangement and follow unique mechanisms of action and degree of disturbances. The development of cardiovascular risk is associated with post-LT NAFLD, although graft outcomes do not seem to be influenced only by the presence of post-LT NAFLD. Measures in consonance with the management of NAFLD, in general, including lifestyle modifications and control of metabolic risk factors, hold true for post-LT NAFLD. Tailoring immunosuppression strategies with early corticosteroid withdrawal and calcineurin inhibitor minimization balancing against the risk of graft rejection constitutes important nuances in the individualized management of post-LT NAFLD.

The plasma degradome reflects later development of NASH fibrosis after liver transplant

Although liver transplantation (LT) is an effective therapy for cirrhosis, the risk of post-LT NASH is alarmingly high and is associated with accelerated progression to fibrosis/cirrhosis, cardiovascular disease and decreased survival. Lack of risk stratification strategies hampers early intervention against development of post-LT NASH fibrosis. The liver undergoes significant remodeling during inflammatory injury. During such remodeling, degraded peptide fragments (i.e., 'degradome') of the ECM and other proteins increase in plasma, making it a useful diagnostic/prognostic tool in chronic liver disease. To investigate whether liver injury caused by post-LT NASH would yield a unique degradome profile that is predictive of severe post-LT NASH fibrosis, a retrospective analysis of 22 biobanked samples from the Starzl Transplantation Institute (12 with post-LT NASH after 5 years and 10 without) was performed. Total plasma peptides were isolated and analyzed by 1D-LC-MS/MS analysis using a Proxeon EASY-nLC 1000 UHPLC and nanoelectrospray ionization into an Orbitrap Elite mass spectrometer. Qualitative and quantitative peptide features data were developed from MSn datasets using PEAKS Studio X (v10). LC-MS/MS yielded ~ 2700 identifiable peptide features based on the results from Peaks Studio analysis. Several peptides were significantly altered in patients that later developed fibrosis and heatmap analysis of the top 25 most significantly changed peptides, most of which were ECM-derived, clustered the 2 patient groups well. Supervised modeling of the dataset indicated that a fraction of the total peptide signal (~ 15%) could explain the differences between the groups, indicating a strong potential for representative biomarker selection. A similar degradome profile was observed when the plasma degradome patterns were compared being obesity sensitive (C57Bl6/J) and insensitive (AJ) mouse strains. The plasma degradome profile of post-LT patients yielded stark difference based on later development of post-LT NASH fibrosis. This approach could yield new "fingerprints" that can serve as minimally-invasive biomarkers of negative outcomes post-LT.

The plasma degradome reflects later development of NASH fibrosis after liver transplant

Although liver transplantation (LT) is an effective therapy for cirrhosis, the risk of post-LT NASH is alarmingly high and is associated with accelerated progression to fibrosis/cirrhosis, cardiovascular disease, and decreased survival. Lack of risk stratification strategies hamper liver undergoes significant remodeling during inflammatory injury. During such remodeling, degraded peptide fragments (i.e., 'degradome') of the ECM and other proteins increase in plasma, making it a useful diagnostic/prognostic tool in chronic liver disease. To investigate whether inflammatory liver injury caused by post-LT NASH would yield a unique degradome profile, predictive of severe post-LT NASH fibrosis, we performed a retrospective analysis of 22 biobanked samples from the Starzl Transplantation Institute (12 with post-LT NASH after 5 years and 10 without). Total plasma peptides were isolated and analyzed by 1D-LC-MS/MS analysis using a Proxeon EASY-nLC 1000 UHPLC and nanoelectrospray ionization into an Orbitrap Elite mass spectrometer. Qualitative and quantitative peptide features data were developed from MSn datasets using PEAKS Studio X (v10). LC-MS/MS yielded ∼2700 identifiable peptide features based on the results from Peaks Studio analysis. Several peptides were significantly altered in patients that later developed fibrosis and heatmap analysis of the top 25 most significantly-changed peptides, most of which were ECM-derived, clustered the 2 patient groups well. Supervised modeling of the dataset indicated that a fraction of the total peptide signal (∼15%) could explain the differences between the groups, indicating a strong potential for representative biomarker selection. A similar degradome profile was observed when the plasma degradome patterns were compared being obesity sensitive (C57Bl6/J) and insensitive (AJ) mouse strains. Both The plasma degradome profile of post-LT patients yields stark difference based on later development of post-LT NASH fibrosis. This approach could yield new "fingerprints" that can serve as minimally-invasive biomarkers of negative outcomes post-LT.

Growing challenge of post-liver transplantation non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is one of the leading causes of chronic liver disease, cirrhosis, and hepatocellular carcinoma worldwide, with an estimated prevalence of 25%. Post-liver transplantation (LT) recurrent or de novo hepatic steatosis is a common complication in recipients, irrespective of transplantation indication. Risk factors for graft steatosis mainly include obesity, immunosuppression, donor steatosis, and genetic factors. Liver transplant recipients are at high risk of developing insulin resistance, new-onset diabetes, and post-transplantation metabolic syndrome that is highly associated with immunosuppressive treatment. Post-LT NAFLD is often underdiagnosed due to the poor sensitivity of most routine imaging methods. The gold standard for the diagnosis of hepatic steatosis is liver biopsy, which is, however, limited to more complex cases due to its invasive nature. There is no approved pharmacotherapy in NAFLD. Lifestyle modification remains the cornerstone in NAFLD treatment. Other treatment strategies in post-LT NAFLD include lifestyle modifications, pharmacotherapy, bariatric surgery, and tailored immunosuppression. However, these approaches originate from recommendations in the general population, as there is scarce data regarding the safety and efficacy of current management strategies for NAFLD in liver transplant patients. Future prospective studies are required to achieve tailored treatment for these patients.

Gender Differences in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) has currently emerged as the most common liver disorder in both developed and developing countries. It has been observed that NAFLD exhibits sexual dimorphism, and there is limited understanding on the sex differences in adults with NAFLD. Nonalcoholic fatty liver disease shows marked differences in prevalence and severity with regards to gender. There are considerable biological disparities between males and females attributed to differences in the chromosomal makeup and sex hormone levels, distinct from the gender differences resulting from the sociocultural influences that lead to differences in lifestyle, which have a significant impact on the pathogenesis of this complex disorder. A multitude of factors contributes to the gender disparities seen and need to be researched in-depth to better understand the mechanisms behind them and the therapeutic measures that can be taken. In this article, we will review the gender disparities seen in NAFLD, as well as recent studies highlighting certain gender-specific factors contributing to its varying prevalence and severity.

HOW TO CITE THIS ARTICLE

Nagral A, Bangar M, Menezes S, et al. Gender Differences in Nonalcoholic Fatty Liver Disease. Euroasian J Hepato-Gastroenterol 2022;12(Suppl 1):S19-S25.

Extrahepatic organs in the development of non-alcoholic fatty liver disease in liver transplant patients

BACKGROUND AND OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent in patients who undergo liver transplantation (LT). Whereas there is huge data on NAFLD, little is known about NAFLD in LT. In this review, we aim to explore extrahepatic organs and their potential mechanisms in the development of NAFLD in LT patients and discuss current limitations in preclinical and clinical scenarios with suggestions for future study.

METHODS

The following keywords, such as NAFLD, NASH, liver transplant, therapy, pathogenesis and biomarkers, were set for literature retrieval. The articles which were published articles in English till 25th June 2020 in PubMed database were included, and there is no limit for the study design type.

KEY CONTENT AND FINDINGS

Following LT, there are significant shifts in the microbiota and farnesoid X receptor may be a potential therapeutic target for NAFLD in LT settings. The roles of probiotics and diet on NALFD remain inconclusive in LT background. Nevertheless, the adipokines and cytokines disorder and local insulin resistance of adipose tissue may contribute to NAFLD process. Bariatric surgeries are promising in controlling de novo and recurrent NAFLD with significant reduction in abdominal adipose tissue, despite the optimal timing is inconclusive in LT cases. Furthermore, circumstantial evidence indicates that miRNA-33a may function as a mediator bridging sarcopenia and NAFLD of post-LT. β-Hydroxy-β-Methyl-Butyrate treatment could improve muscle status in graft recipients and shows protective potential for NAFLD in LT settings.

CONCLUSIONS

Gut, adipose tissue and muscle are intricately intertwined in promoting NAFLD in LT cases. Further animal studies are needed to deepen our understanding of mechanisms in multi-organ crosstalk. High quality clinical trials are warrant for making guidelines and developing management strategies on NAFLD after LT.

LUM is the hub gene of advanced fibrosis in nonalcoholic fatty liver disease patients

INTRODUCTION

Advanced fibrosis in nonalcoholic fatty liver disease (NAFLD) is associated with a poor prognosis. The genetic factors contributing to fibrosis in NAFLD have been described. However, the genetic mechanism and hub genes of advanced fibrosis have not been elucidated to date. In this study, we performed a weighted gene coexpression network analysis (WGCNA) to identify the hub genes related to advanced fibrosis in NAFLD.

MATERIALS AND METHODS

The datasets GSE89632 and GSE31803 of NAFLD patients were selected from the Gene Expression Omnibus (GEO) database of NCBI and analyzed by WGCNA. The hub genes were selected in the GSE31803 dataset and verified in the GSE31803 dataset. Gene Ontology (GO) term enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of the dataset were also performed.

RESULTS

The gene LUM was identified as the hub gene in the datasets GSE89632 and GSE31803 according to three different algorithms (gene significance and module membership, the pathways of the genes, and protein expressed by the genes). The functional enrichment analysis shows that the identified module is related to the extracellular matrix, regulation of cell proliferation, and the inflammatory response. The metabolic pathway analysis identified metabolic pathways and focal adhesion as the most important pathways.

CONCLUSION

By a variety of methods, LUM was identified as the hub gene of advanced fibrosis in patients with NAFLD. Therefore, further research on the LUM gene is warranted.

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.

Hepatic steatosis and liver fat contents in liver transplant recipients are associated with serum adipokines and insulin resistance

Our data about pathogenesis of hepatic steatosis after liver transplantation is scarce. This study aimed to investigate the association between serum adipokines and insulin resistance with hepatic steatosis in liver transplant recipients. We investigated the association between insulin resistance, serum adiponectin, insulin, and leptin with hepatic steatosis in a cohort of liver transplant recipients. Homeostatic model assessment of insulin resistance 2 (HOMA 2-IR) was used for estimation of insulin resistance. Hepatic steatosis was determined using ultrasound and controlled attenuation parameter (CAP). A total of 178 patients were included. 79 patients (44.4%) had hepatic steatosis. Serum adiponectin (OR: 0.912; 95% CI 0.869–0.957; P < 0.001), serum leptin (OR: 1.060; 95% CI 1.017–1.102; P = 0.005), HOMA2-IR (OR: 1.671; 95% CI 1.049–2.662; P = 0.031), and post-transplant diabetes mellitus (PTDM) (OR: 5.988; 95% CI 1.680–21.276; P = 0.006) were independently associated with hepatic steatosis after liver transplantation. CAP values were negatively correlated with serum adiponectin (P = 0.011) and positively correlated with serum insulin (P = 0.001), leptin (P < 0.001) and HOMA2-IR (P < 0.001). Insulin resistance and alterations in adipokines might have central role in pathogenesis of hepatic steatosis after liver transplantation and can be targeted for diagnostic and therapeutic purposes.

Nonalcoholic steatohepatitis recurrence after liver transplant

Nonalcoholic steatohepatitis (NASH) is the fastest growing indication for liver transplant (LT)worldwide and is deemed to be the foremost indication in the near future. Recurrence of NASH can occur post LT and has been observed to be a common phenomenon. Baseline metabolic co-morbidities and worsening of metabolic profile post LT are the principal drivers of NASH recurrence. Liver biopsy remains the gold standard for establishing the diagnosis. However, noninvasive methods including transient elastography (TE) and magnetic resonance imaging (MRI) seem to be promising. The implications of recurrent NASH on post LT outcomes, graft steatosis, progression to fibrosis, overall survival, and cardiovascular associations warrant careful evaluation. Control of metabolic parameters and weight gain along with tailored immunosuppression remain the cornerstone of management. Extrapolation of the ever-increasing armamentarium of NASH pharmacotherapy specifically in this population of recurrent NAFLD remains a challenge for the future.

Non-alcoholic fatty liver disease after liver transplantation in patients with non-alcoholic steatohepatitis and cryptogenic cirrhosis: the impact of pre-transplant graft steatosis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) may occur in liver transplant recipients. This study aimed to investigate the prevalence and risk factors of NAFLD after liver transplantation in patients with NASH and cryptogenic cirrhosis, focusing on the impact of graft steatosis.

METHODS

Patients with NASH and cryptogenic cirrhosis who had undergone liver transplantation in Shiraz transplant center between March 2010 and March 2017 were included. NAFLD was diagnosed after liver transplantation using ultrasonography and transient elastography.

RESULTS

73 patients with NASH and 389 with cryptogenic cirrhosis were included. NAFLD was diagnosed in 33 patients (56.9%) in NASH group and 96 patients (26.7%) in cryptogenic group (OR: 3.61; CI: 2.04-6.39; P-Value < 0.001), using ultrasound. Obesity and post-transplant hyperlipidemia were independent predictors of NAFLD after liver transplantation (P < 0.05). NAFLD was diagnosed in 32.9% of patients with graft macrosteatosis compared to 29.9% in patients without graft macrosteatosis (OR: 1.51; 95%CI: 0.755-1.753). 28% of the patients with macrosteatosis ≥30% had NAFLD after liver transplantation compared to 31.4% with macrosteatosis <30% (OR: 1.175; 95% CI: 0.346-2.091).

CONCLUSION

Liver graft steatosis before transplantation was not associated with the occurrence of NAFLD after liver transplantation.

Minimally Invasive Sleeve Gastrectomy as a Surgical Treatment for Nonalcoholic Fatty Liver Disease in Liver Transplant Recipients

BACKGROUND

Obesity is a major public health burden that affects the transplant community because of its key role in fatty liver disease and transplantation outcomes.

OBJECTIVES

To evaluate the role of sleeve gastrectomy in treating recurrent and de novo nonalcoholic fatty liver disease (NAFLD) in liver transplant recipients.

SETTING

A university hospital.

METHODS

We describe 2 obese liver transplant recipients with recurrent and de novo NAFLD who underwent minimally invasive metabolic and bariatric surgery.

RESULTS

The surgery was performed successfully, with much of the operative time consumed by enterolysis. There were no intraoperative or postoperative complications. At last follow-up appointment (16 months postoperatively), there was a mean reduction in weight (31.98 kg), body mass index (10.2 kg/m²), glycosylated hemoglobin (1.05%), alanine aminotransferase (38 IU/L), steatosis score (0.34), and fibrosis score (0.05). The mean decrease in 6-month postoperative hepatic fat quantification was 6%.

CONCLUSIONS

These cases show that metabolic and bariatric surgery in obese, posttransplant recipients with recurrent and de novo nonalcoholic steatohepatitis lead to improved steatosis and reduced obesity and obesity-associated comorbidities.

Weight Gain and De Novo Metabolic Disorders after Liver Transplantation

The development of nutritional and metabolic abnormalities represents an important burden in patients after liver transplantation (LT). Our study aimed at evaluating the incidence, time of onset, and risk factors for nutritional and metabolic abnormalities in patients after LT. The study was a single-center retrospective study. Consecutive patients undergoing elective LT from 2000 to 2016 were enrolled. The presence of at least two among arterial hypertension (AH), diabetes mellitus (DM), dyslipidemia, and obesity (BMI ≥ 30 Kg/m²) was utilized to define patients with the metabolic disorder (MD). Three hundred and fifteen patients were enrolled; the median age was 56 years (68% males). Non-alcoholic steatohepatitis (NASH) was the origin of liver disease in 10% of patients. During follow-up, 39% of patients developed AH, 18% DM, and 17% dyslipidemia. Metabolic disorders were observed in 32% of patients. The NASH etiology (OR: 6.2; CI 95% 0.5–3; p = 0.003) and a longer follow-up (OR: 1.2; CI 95% 0.004–0.02; p = 0.002) were associated with de novo MD. In conclusion, nutritional and metabolic disorders are a frequent complication after LT, being present in up to one-third of patients. The NASH etiology and a longer distance from LT are associated with de novo MD after LT.

Sex hormone levels by presence and severity of cirrhosis in women with chronic hepatitis C virus infection

Cirrhosis is associated with hormonal dysregulation, as evidenced by secondary amenorrhoea in reproductive-aged women, and feminization of cirrhotic men. Whether hormone levels vary by severity of cirrhosis in women is not known. If identified, such changes may have important clinical relevance, particularly, as low sex hormone binding globulin (SHBG) and follicle stimulating hormone (FSH) are known to promote metabolic and cardiovascular disease in women. In a cohort of post-menopausal women with chronic hepatitis C virus (HCV) infection, we compared comprehensive sex hormone levels by presence of cirrhosis, as well as across Child-Turcotte-Pugh (CTP) class. Results: There were n = 18 cirrhotic and n = 21 noncirrhotic women with a median age of 57 years (interquartile range [IQR] 53-62). Compared to noncirrhotics, cirrhotic women had higher oestradiol (11.0 vs 6.0 pg/mL, P = 0.05) and oestrone levels (32.0 vs 8.0 ng/mL, P < 0.001), and lower sex hormone binding globulin (SHBG) (69.2 vs 155.6 nmol/L, P = 0.001), and FSH levels (4.9 vs 89.6 mIU/mL, P < 0.001). Among cirrhotic women, there was a progressive decline in FSH and SHBG and concurrent rise in oestrone levels from CTP class A to C (test of trend, P values ≤0.02). Cirrhosis is associated with lower FSH and SHBG levels in cirrhotic compared to noncirrhotic women with HCV infection. In cirrhotic women, these levels demonstrate steady decline by disease severity. Given known associations of low SHBG and FSH with cardio-metabolic disease, the clinical implications of hormonal changes by cirrhosis severity in HCV-infected women warrants investigation.

Preventive Strategies for Nonalcoholic Fatty Liver Disease After Liver Transplantation

Post-transplant nonalcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis (NASH) is common and can be recurrent or de novo. The available data suggest that progression of fibrosis is accelerated in these patients compared to NASH in general population. The long-term data suggest more risk of metabolic syndrome and associated metabolic comorbidities and cardiovascular disease in these patients. The current review focuses on prevalence and prevention/treatment of post-transplant NAFLD or NASH.

Predictors of De Novo Nonalcoholic Fatty Liver Disease After Liver Transplantation and Associated Fibrosis

Nonalcoholic fatty liver disease (NAFLD) can occur de novo in patients undergoing liver transplantation (LT) for indications other than NAFLD, and it has been increasingly recognized as a complication in the post-LT setting. This study aims to better characterize de novo NAFLD after LT by identifying risk factors for its development, describing incidence and extent of fibrosis, assessing the diagnostic utility of noninvasive serum fibrosis algorithms, and comparing survival to those without NAFLD. This was a retrospective single-center analysis of de novo NAFLD in a post-LT cohort. Those whose primary indication for LT was nonalcoholic steatohepatitis (NASH) were excluded. Risk factors were analyzed by univariate and multivariate analyses. De novo NAFLD and fibrosis were assessed on posttransplant liver biopsies, and noninvasive fibrosis scores were calculated from concomitant blood tests. After applying the exclusion criteria, 430 for-cause post-LT biopsies were evaluated; 33.3% (n = 143) had evidence of de novo steatosis and/or NASH at a median of 3.0 years after transplant. On multivariate analysis, body mass index (BMI; odds ratio [OR], 1.12; P < 0.001), diabetes mellitus (OR, 3.01; P = 0.002), hepatitis C virus (OR, 4.61; P < 0.001), weight gain (OR, 1.03; P = 0.007), and sirolimus use (OR, 3.11; P = 0.02) were predictive of de novo NAFLD after LT. Significant fibrosis (≥F2) was present in almost 40% of the cohort. Noninvasive serum fibrosis scores were not useful diagnostic tests. There was no significant difference in the short-term or longterm survival of patients who developed de novo NAFLD. In conclusion, diabetes, BMI, weight gain after LT, and sirolimus-based immunosuppression, in keeping with insulin resistance, were the only modifiable factors associated with development of de novo NAFLD. A significant proportion of patients with de novo NAFLD had fibrosis and given the limited utility of noninvasive serum fibrosis algorithms, alternative noninvasive tools are required to screen for fibrosis in this population. There was no significant difference in the short-term or longterm survival of patients who developed de novo NAFLD.