Performance of transient elastography and serum fibrosis biomarkers for non-invasive evaluation of recurrent fibrosis after liver transplantation: A meta-analysis. PLoS One. 2017;12:e0185192. [PMID: 28953939 PMCID: PMC5617176 DOI: 10.1371/journal.pone.0185192]

Utilizing Machine Learning to Predict Liver Allograft Fibrosis by Leveraging Clinical and Imaging Data

BACKGROUND AND AIM

Liver transplant (LT) recipients may succumb to graft-related pathologies, contributing to graft fibrosis (GF). Current methods to diagnose GF are limited, ranging from procedural-related complications to low accuracy. With recent advances in machine learning (ML), we aimed to develop a noninvasive tool using demographic, clinical, laboratory, and B-mode ultrasound (US) features to predict significant fibrosis (METAVIR≥F2).

METHODS

We used a nested 10-fold cross-validation approach with grid-search for hyperparameter fine-tuning to train an artificial neural network (ANN) and a support vector machine (SVM) to classify mild fibrosis (F0-F1) and significant fibrosis (F2-F4) on 1131 patients. We calculated Shapley values to identify top-ranked features, determining the contribution of each feature to model predictions. For the imaging-based model, we used 4819 images with 892 studies trained on the residual network 18 (ResNet18) model to classify F0-F1 versus F3-F4.

RESULTS

We determined the ANN performed the best when compared to the SVM and standard biomarkers, with an AUC ranging from 0.77 to 0.81. The ResNet18 model was unable to diagnose advanced GF, leading to the training AUCs ranging from 0.89 to 0.97, while the validation and testing AUCs were 0.43-0.63. Shapley analysis highlighted the following top-ranked features associated with significant GF: hepatitis C at transplant, recipient age, recipient sex, and certain blood markers such as creatinine and hemoglobin.

CONCLUSION

Noninvasive approaches using ML for predicting significant GF perform well when considering demographic, clinical, and laboratory data; however, this performance is not enhanced with the use of US images.

Metabolic issues in patients with metabolic dysfunction-associated steatohepatitis (MASH) and their impact on MASH recurrence following liver transplantation: A narrative review

Decompensated cirrhosis secondary to metabolic dysfunction-associated steatohepatitis (MASH) is not only a common indication for liver transplant (LT) but is becoming the leading cause of LT in postmenopausal women in the United States. Given the different complex mechanisms involved in the occurrence of MASH, it is being recognized as the hepatic manifestation of the metabolic syndrome. There are multiple metabolic issues associated with MASH, including obesity, DMT2, cardiovascular disease, and chronic kidney disease, which need to be addressed in the pretransplant and posttransplant setting for better patient outcomes. Recurrence of MASH following LT can occur due to many reasons including reversal of the catabolic state seen in cirrhosis, improvement in appetite, and the effect of certain post-LT medications on the graft; however, managing recurrence can be challenging and thus urges addressing these issues before transplant, in addition to recognizing, and treating them in the posttransplant setting. In this review, we discuss the various metabolic issues that face patients with MASH and the medical and surgical management options available to improve outcomes and reduce chances of recurrence.

Recurrence of Primary Disease After Adult Liver Transplant - Risk Factors, Early Diagnosis, Management, and Prevention

Liver transplantation offers a new lease of life to patients with end-stage liver disease and hepatocellular carcinoma. However, the implantation of an exogenous allograft and the accompanying immunosuppression bring their own challenges. Moreover, the persistence of risk factors for the initial liver insult place the new graft at a higher risk of damage. With the increasing number of liver transplants along with the improvement in survival posttransplant, the recurrence of primary disease in liver grafts has become more common. Pre-2015, the most common disease to recur after transplant was hepatitis C. However, directly acting antivirals have nearly eliminated this problem. The greatest challenge of disease recurrence we now face are those of nonalcoholic steatohepatitis, alcohol-related liver disease, and primary sclerosing cholangitis. We focus on the epidemiology and pathophysiology of the recurrence of primary disease after transplant. We also discuss means of early identification, risk stratification, prevention, and management of recurrent primary disease after liver transplantation.

Elastography-The New Standard in the Assessment of Fibrosis After Pediatric Liver Transplantation?

BACKGROUND

The development of graft fibrosis after pediatric liver transplantation (PLT) remains a major concern as it can lead to graft failure and ultimately graft loss. Elastography is a non-invasive method to assess liver fibrosis, but its role in the posttransplant setting is unclear. The aim of our study was to evaluate shear wave elastography (SWE) in the assessment of liver fibrosis after PLT, including split-liver recipients.

METHODS

We retrospectively analyzed data from PLT recipients who underwent surveillance liver biopsy and concurrent 2D-SWE during the study period from April 2018 to July 2021. Spearman's correlation was used to compare histologic fibrosis stages with liver stiffness measurements (LSM) by 2D-SWE. AUROC analysis was performed to evaluate the performance. One sample t-test was used to compare results with reference values of healthy children.

RESULTS

62 cases were included. 29% showed histologic fibrosis. LSM by 2D-SWE were feasible in all children regardless of age or graft type. There was a significant correlation between LSM and fibrosis stage for all three scoring systems used (Ishak, p = 0.003; METAVIR, p = 0.005; LAF Score, p = 0.003). Patients with a history of biliary complications had increased liver stiffness (p = 0.015). The AUROC of 2D-SWE for predicting significant liver graft fibrosis was 0.81. Liver stiffness after PLT without graft fibrosis was higher than in healthy subjects, but comparable to that in children with chronic liver disease without fibrosis.

CONCLUSION

2D-SWE can reliably detect children with significant liver graft fibrosis, even in split-liver recipients. This study demonstrates the value of a non-invasive tool for fibrosis staging after PLT. 2D-SWE has the potential to improve long-term outcomes after PLT and to reduce the number of surveillance liver biopsies. But elastography is not a substitute for liver biopsy.

Metabolic-Dysfunction-Associated Steatotic Liver Disease (MASLD) after Liver Transplantation: A Narrative Review of an Emerging Issue

The development of steatotic liver disease after liver transplant (LT) is widely described, and epidemiological data have revealed an increased incidence in recent times. Its evolution runs from simple steatosis to steatohepatitis and, in a small proportion of patients, to significant fibrosis and cirrhosis. Apparently, post-LT steatotic disease has no impact on the recipient's overall survival; however, a higher cardiovascular and malignancy burden has been reported. Many donors' and recipients' risk factors have been associated with this occurrence, although the recipient-related ones seem of greater impact. Particularly, pre- and post-LT metabolic alterations are strictly associated with steatotic graft disease, sharing common pathophysiologic mechanisms that converge on insulin resistance. Other relevant risk factors include genetic variants, sex, age, baseline liver diseases, and immunosuppressive drugs. Diagnostic evaluation relies on liver biopsy, although non-invasive methods are being increasingly used to detect and monitor both steatosis and fibrosis stages. Management requires a multifaceted approach focusing on lifestyle modifications, the optimization of immunosuppressive therapy, and the management of metabolic complications. This review aims to synthesize the current knowledge of post-LT steatotic liver disease, focusing on the recent definition of metabolic-dysfunction-associated steatotic liver disease (MASLD) and its metabolic and multisystemic concerns.

Noninvasive assessment of liver fibrosis and portal hypertension

PURPOSE OF REVIEW

The result of ongoing liver injury - and disease, regardless of cause - is fibrosis, and fibrosis appears to be a critically important result of ongoing injury. Further, in a number of different liver diseases, the presence of fibrosis has prognostic value. Therefore, the assessment of fibrosis is of critical clinical importance. Given the importance of fibrosis, there has been a rapid evolution in the use of noninvasive liver tests. This review highlights a number of the core principles surrounding.

RECENT FINDINGS

The use of noninvasive test has progressed rapidly over the last decade and data are rapidly accumulating. New terminology has been adapted by the American Association for the Study of Liver Disease (AASLD) for noninvasive assessment of liver disease and termed 'NILDA' (Non-Invasive Liver Disease Assessment). Blood based such as APRI and or FIB-4 and imaging tests such as liver stiffness measurement (LSM) have moderate to high degrees of accuracy for detection of advanced liver fibrosis (≥ F2) and even higher accuracy for detection of severe fibrosis (F4 or cirrhosis). NILDA are particularly effective at the ends of the liver disease spectrum. For example, a very low LSM (less than 7 kPa) essentially excludes significant fibrosis or portal hypertension, and a very high LSM (> 25 kPa) makes significant fibrosis with portal hypertension (cirrhosis) highly likely.

SUMMARY

NILDA are currently front and center in terms of assessment of the severity of liver disease. In all patients with known or suspected liver disease, noninvasive blood tests, including APRI and or FIB-4, should be the initial choice to assess the severity of liver fibrosis and/or portal hypertension. In most patients, these tests should be followed with imaging evaluation. The most commonly available imaging is LSM, which appears to be more accurate in predicting fibrosis severity, and is superior to blood tests in the assessment of portal hypertension. In situations in which there is diagnostic uncertainly, liver biopsy with or without HVPG remains an important consideration.

Harnessing Metabolites as Serum Biomarkers for Liver Graft Pathology Prediction Using Machine Learning

Graft injury affects over 50% of liver transplant (LT) recipients, but non-invasive biomarkers to diagnose and guide treatment are currently limited. We aimed to develop a biomarker of graft injury by integrating serum metabolomic profiles with clinical variables. Serum from 55 LT recipients with biopsy confirmed metabolic dysfunction-associated steatohepatitis (MASH), T-cell mediated rejection (TCMR) and biliary complications was collected and processed using a combination of LC-MS/MS assay. The metabolomic profiles were integrated with clinical information using a multi-class Machine Learning (ML) classifier. The model's efficacy was assessed through the Out-of-Bag (OOB) error estimate evaluation. Our ML model yielded an overall accuracy of 79.66% with an OOB estimate of the error rate at 19.75%. The model exhibited a maximum ability to distinguish MASH, with an OOB error estimate of 7.4% compared to 22.2% for biliary and 29.6% for TCMR. The metabolites serine and serotonin emerged as the topmost predictors. When predicting binary outcomes using three models: Biliary (biliary vs. rest), MASH (MASH vs. rest) and TCMR (TCMR vs. rest); the AUCs were 0.882, 0.972 and 0.896, respectively. Our ML tool integrating serum metabolites with clinical variables shows promise as a non-invasive, multi-class serum biomarker of graft pathology.

Assessment of hepatic fibrosis with non-invasive indices in subjects with diabetes before and after liver transplantation

Introduction

One of the most common complications of cirrhosis is diabetes, which prevalence is strictly related to severity of hepatopathy. Actually, there are no data on the persistence of post-transplant glucose abnormalities and on a potential impact of diabetes on development of fibrosis in the transplanted liver. To this aim, we evaluated liver fibrosis in cirrhotic subjects before and after being transplanted.

Methods

The study included 111 individuals who had liver transplantation. The assessment was performed before and two years after surgery to investigate a potential impact of the persistence of diabetes on developing de novo fibrosis in the transplanted liver. The degree of fibrosis was assessed using the Fibrosis Index Based on 4 Factors (FIB-4) and the Aspartate to Platelet Ratio Index (APRI).

Results

At pre-transplant evaluation, 63 out of 111 (56.8%) subjects were diabetic. Diabetic subjects had higher FIB-4 (Geometric mean, 95% confidence interval: 9.74, 8.32-11.41 vs 5.93, 4.71-7.46, P<0.001) and APRI (2.04, 1.69-2.47 vs 1.18, 0.90-1.55, P<0.001) compared to non-diabetic subjects. Two years after transplantation, 39 out of 111 (35.1%) subjects remained with diabetes and continued to show significantly higher FIB-4 (3.14, 2.57-3.82 vs 1.87, 1.55-2.27, P<0.001) and APRI (0.52, 0.39-0.69 vs 0.26, 0.21-0.32, P<0.001) compared to subjects without diabetes.

Discussion

Thus, persistence of diabetes after surgery is a possible risk factor for an evolution to fibrosis in the transplanted liver, potentially leading to worsened long-term outcomes in this population.

Elevated Plasma CXCL8 Concentrations in Significant Fibrosis but Not in Subclinical Rejection After Adult Liver Transplantation

Background

The noninvasive detection of subclinical graft injury including subclinical T cell-mediated rejection (subTCMR) is one of the unresolved challenges after liver transplantation. Recently, serum C-X-C motif chemokine ligand 8 (CXCL8) was proposed as a highly accurate marker of subTCMR in pediatric liver transplant recipients. We aimed to evaluate the accuracy of the quantification of this chemokine for predicting subTCMR in adult liver transplant recipients, as well as its capacity to classify patients who could benefit from immunosuppression reduction.

Methods

Plasma CXCL8 concentrations were measured retrospectively in a prospectively collected cohort of adult liver transplant recipients with well-characterized histologic phenotypes.

Results

In total, 78 patients were included. Median plasma CXCL8 concentrations did not differ (P = 0.24) between patients without histological evidence of rejection (3.6 [0.4-22.0] pg/mL), subTCMR (11.5 [0.4-41.0] pg/mL), clinical TCMR (9.4 [0.4-40.5] pg/mL), and other etiologies of graft injury (8.7 [0.4-31.2] pg/mL). Likewise, plasma CXCL8 concentrations did not discriminate between patients within and outside histologic criteria for immunosuppression reduction that were proposed by the 2016 Banff Working Group on Liver Allograft Pathology (cutoff: 10.9 pg/mL, sensitivity: 0.48, and specificity: 0.79). Furthermore, weak correlation was found between plasma CXCL8 and alanine aminotransferase and aspartate aminotransferase (Spearman ρ = 0.18 and 0.25). Patients with significant fibrosis (17.8 [0.4-40.5] pg/mL) showed higher plasma CXCL8 concentrations than patients without fibrosis (8.2 [0.4-41.0] pg/mL; P = 0.05).

Conclusions

Plasma CXCL8 concentrations are not predictive of subclinical graft injury or of histological criteria for the minimization of immunosuppression in adult liver transplant recipients.

Prospective comparison of an 18-gauge versus 16-gauge needle for percutaneous liver core-needle biopsy in children

PURPOSE

The objective of this study was to analyzed the impact of needle gauge (G) on the adequacy of specimens and hemorrhagic complications in pediatric patients undergoing ultrasound (US)-guided transplanted liver biopsies.

METHODS

The study included 300 consecutive biopsies performed in 282 pediatric patients (mean age 6.75 ± 3.82 years, range 0.84-17.90) between December 2020 and April 2022. All pediatric patients that referred to our institution for US-guided core-needle liver biopsy (CNLB) were randomized to undergo 16-G or 18-G CNLB. Hemorrhagic complications were qualitatively evaluated. The number of complete portal tracts (CPTs) per specimen was counted and specimen adequacy was assessed based on the American Association for the Study of Liver Diseases guidelines.

RESULTS

The incidence of bleeding was 7.00% (n = 21) and adequate specimens for accurate pathological diagnosis were obtained from 98.33% (n = 295) of patients. There was no significant difference in the incidence or amount of bleeding between the 16-G and 18-G groups (11 vs 10, p = 0.821; 35.0 mL vs 31.3 mL, p = 0.705). Although biopsies obtained using a 16-G needle contained more complete portal tracts than those obtained using an 18-G needle (20.0 vs 18.0, p = 0.029), there was no significant difference in specimen inadequacy according to needle gauge (2 vs 3, p = 1.000).

CONCLUSIONS

Biopsy with a 16-G needle was associated with a greater number of CPTs but did not increase the adequate specimen rate. There was no significant difference in the complication rate between 16-G biopsy and 18-G biopsy.

Prospective comparison of liver stiffness measurement methods in surveillance biopsies after liver transplantation

Background

Liver stiffness measurements (LSMs) have proven useful for non-invasive detection of fibrosis. Previous studies of LSMs after transplantation were performed in cohorts dominated by hepatitis C reinfections and indication biopsies for the evaluation of graft dysfunction. However, the diagnostic fidelity of LSMs for fibrosis is biased by inflammation e.g., during replicative hepatitis C or rejection.

Materials and methods

The current study aimed for a head-to-head comparison of two different LSMs, acoustic radiation force impulse (ARFI) and transient elastography (TE), and a determination of cut-off values for the detection of advanced fibrosis (any LAF score component ≥2) in grafts undergoing surveillance biopsies (svLbx) without recurrent hepatitis C.

Results

103 svLbx were paired with valid LSMs at time of biopsy. AUROC analyses showed significant positive correlation with fibrosis for both methods (TE: AUROC = 0.819 (p < 0.001; 95%CI: 0.717-0.921); ARFI: AUROC = 0.771 (p = 0.001; 95%CI: 0.652-0.890). Patients were randomly assigned to training and validation cohorts for both LSM methods. Cut-off values were determined at 1.29 m/s (ARFI) and at 7.5 kPa (TE) in training cohorts. Sensitivity and specificity in training and validation cohorts were: TE: SEN 0.818 and 0.5; SPE 0.742 and 0.885; ARFI: SEN 0.818 and 1.0; SPE 0.75 and 0.586. LSMs were not associated with BANFF criteria for relevant graft injury.

Conclusion

LSM is a good non-invasive tool to screen for advanced graft fibrosis but not for relevant graft injury in patients with (near) normal liver enzymes. Fibrosis cut-off values identified and validated in svLbx were lower than in previous cohorts using indication biopsies.

Long Term Complications of Immunosuppression Post Liver Transplant

Improvement in immunosuppression has led to a remarkable improvement in short-term and long-term outcomes post-liver transplant (LT). However, with improvements in long-term survival, complications related to immunosuppressive drugs, either directly or indirectly, have also increased. The adverse events could be drug-specific, class-specific, or generic. Calcineurin inhibitors (cyclosporine and tacrolimus) are the backbone of the immunosuppression after LT and the main culprit associated with most of the complications, including renal failure, post-transplant diabetes mellitus (PTDM), and metabolic syndrome. Steroids are also implicated in the development of diabetes, osteoporosis, and metabolic syndrome post-LT. The development of infections and de novo malignancies (DNMs) is a generic effect linked to the overall cumulative immunosuppression. The development of these complications significantly hampers the quality of life and leads to increased morbidity and mortality post-LT. Thus, it is important to minimize the cumulative immunosuppression dose while simultaneously preventing allograft rejection. This review provides up-to-date, comprehensive knowledge of the complications of long-term immunosuppression post-LT along with associated risk factors and strategies to minimize the risk of complications.

A Comprehensive Review of Liver Allograft Fibrosis and Steatosis: From Cause to Diagnosis

Despite advances in posttransplant care, long-term outcomes for liver transplant recipients remain unchanged. Approximately 25% of recipients will advance to graft cirrhosis and require retransplantation. Graft fibrosis progresses in the context of de novo or recurrent disease. Recurrent hepatitis C virus infection was previously the most important cause of graft failure but is now curable in the majority of patients. However, with an increasing prevalence of obesity and diabetes and nonalcoholic fatty liver disease as the most rapidly increasing indication for liver transplantation, metabolic dysfunction-associated liver injury is anticipated to become an important cause of graft fibrosis alongside alloimmune hepatitis and alcoholic liver disease. To better understand the landscape of the graft fibrosis literature, we summarize the associated epidemiology, cause, potential mechanisms, diagnosis, and complications. We additionally highlight the need for better noninvasive methods to ameliorate the management of graft fibrosis. Some examples include leveraging the microbiome, genetic, and machine learning methods to address these limitations. Overall, graft fibrosis is routinely seen by transplant clinicians, but it requires a better understanding of its underlying biology and contributors that can help inform diagnostic and therapeutic practices.

Fibrosis and steatosis of the liver graft: Are non-invasive tests useful? A short review

As life expectancy of liver transplanted patients improves, new questions are arising to avoid progressive graft loss. The spectrum of chronic inflammation and fibrosis are known to be important triggers in the alteration of graft function. Liver biopsy remains the gold standard to better understand progressive, normal, and abnormal histological modifications of the graft. In parallel, the interest for metabolic steatosis development in post-transplantation is also growing. Long-term survival of these patients involves the management of comorbidities including metabolic syndrome and cardiovascular diseases. Early detection of altered graft parenchyma, and monitoring of its evolution are undoubtedly essential. Non-invasive methods including transient elastography and fibrosis biomarkers are attractive tools to avoid drawbacks and complications of liver biopsy. Accuracy of these methods are well-known in a pre-transplantation setting, but evidence is lacking in post-transplantation setting. We review current knowledge of progressive liver fibrosis and steatosis development after transplantation and non-invasive methods of their assessment.

Using Artificial Intelligence to Predict Cirrhosis From Computed Tomography Scans

INTRODUCTION

Undiagnosed cirrhosis remains a significant problem. In this study, we developed and tested an automated liver segmentation tool to predict the presence of cirrhosis in a population of patients with paired liver biopsy and computed tomography (CT) scans.

METHODS

We used a cohort of 1,590 CT scans within the Morphomics database to train an automated liver segmentation model using 3D-U-Net and Google's DeeplLabv3+. Imaging features were then automatically calculated from an external test cohort of patients with chronic liver disease who had a paired liver biopsy and CT within 6 months of each other in January 2004-2012. Using gradient boosting decision trees, we developed multivariate models to predict the presence of histologic cirrhosis and evaluated with 5-fold cross-validated c-statistic.

RESULTS

Our cohort had 351 patients; 96 patients had cirrhosis. Of the total cohort, 72 were postliver transplant. Both fibrosis (FIB)-4 and liver morphomics alone performed equally well with area under the receiving operating characteristics of 0.76 (95% confidence interval 0.70-0.81) and 0.71 (95% confidence interval 0.65-0.76), respectively ( P = 0.2). However, the combination of liver morphomics with laboratory values or liver morphomics with laboratory and demographic data resulted in significant improved performance with area under the receiving operating characteristics of 0.84 (0.80-0.89) and 0.85 (0.81-0.90), respectively, compared with FIB-4 alone ( P < 0.001). In a subgroup analysis, we also examined performance in patients without liver transplantation and saw similar augmentation of FIB-4.

DISCUSSION

This proof-of-principle study demonstrates that automatically extracted features within CT scans can be combined with classic electronic medical record data to improve the prediction of cirrhosis in patients with liver disease. This tool may be used in both pretransplant and posttransplant patients and has the potential to improve our ability to detect undiagnosed cirrhosis.

Development of a Radiomics-Based Model to Predict Graft Fibrosis in Liver Transplant Recipients: A Pilot Study

Liver Transplantation is complicated by recurrent fibrosis in 40% of recipients. We evaluated the ability of clinical and radiomic features to flag patients at risk of developing future graft fibrosis. CT scans of 254 patients at 3-6 months post-liver transplant were retrospectively analyzed. Volumetric radiomic features were extracted from the portal phase using an Artificial Intelligence-based tool (PyRadiomics). The primary endpoint was clinically significant (≥F2) graft fibrosis. A 10-fold cross-validated LASSO model using clinical and radiomic features was developed. In total, 75 patients (29.5%) developed ≥F2 fibrosis by a median of 19 (4.3-121.8) months. The maximum liver attenuation at the venous phase (a radiomic feature reflecting venous perfusion), primary etiology, donor/recipient age, recurrence of disease, brain-dead donor, tacrolimus use at 3 months, and APRI score at 3 months were predictive of ≥F2 fibrosis. The combination of radiomics and the clinical features increased the AUC to 0.811 from 0.793 for the clinical-only model (p = 0.008) and from 0.664 for the radiomics-only model (p < 0.001) to predict future ≥F2 fibrosis. This pilot study exploring the role of radiomics demonstrates that the addition of radiomic features in a clinical model increased the model's performance. Further studies are required to investigate the generalizability of this experimental tool.

Non-Invasive Measurement of Hepatic Fibrosis by Transient Elastography: A Narrative Review

Transient elastography by FibroScan® (Echosens, Paris, France) is a non-invasive method that can provide a reliable measurement of liver fibrosis through the evaluation of liver stiffness. Despite its limitations and risks, liver biopsy has thus far been the only procedure able to provide data to quantify fibrosis. Scientific evidence and clinical practice have made it possible to use FibroScan® in the diagnostic work-up of several liver diseases to monitor patients' long-term treatment response and for complication prevention. For these reasons, this procedure is widely used in clinical practice and is still being investigated for further applications. The aim of this narrative review is to provide a comprehensive overview of the main applications of transient elastography in the current clinical practice.

A deep learning framework for personalised dynamic diagnosis of graft fibrosis after liver transplantation: a retrospective, single Canadian centre, longitudinal study

BACKGROUND

Recurrent graft fibrosis after liver transplantation can threaten both graft and patient survival. Therefore, early detection of fibrosis is essential to avoid disease progression and the need for retransplantation. Non-invasive blood-based biomarkers of fibrosis are limited by moderate accuracy and high cost. We aimed to evaluate the accuracy of machine learning algorithms in detecting graft fibrosis using longitudinal clinical and laboratory data.

METHODS

In this retrospective, longitudinal study, we trained machine learning algorithms, including our novel weighted long short-term memory (LSTM) model, to predict the risk of significant fibrosis using follow-up data from 1893 adults who had a liver transplantation between Feb 1, 1987, and Dec 30, 2019, with at least one liver biopsy post transplantation. Liver biopsy samples with indefinitive fibrosis stage and those from patients with multiple transplantations were excluded. Longitudinal clinical variables were collected from transplantation to the date of last available liver biopsy. Deep learning models were trained on 70% of the patients as the training set and 30% of the patients as the test set. The algorithms were also separately tested on longitudinal data from patients in a subgroup of patients (n=149) who had transient elastography within 1 year before or after the date of liver biopsy. Weighted LSTM model performance for diagnosing significant fibrosis was compared against LSTM, other deep learning models (recurrent neural network and temporal convolutional network), and machine learning models (Random Forest, Support vector machines, Logistic regression, Lasso regression, and Ridge regression) and aspartate aminotransferase-to-platelet ratio index (APRI), fibrosis-4 index (FIB-4), and transient elastography.

FINDINGS

1893 people who had a liver transplantation (1261 [67%] men and 632 [33%] women) with at least one liver biopsy between Jan 1, 1992, and June 30, 2020, were included in the study (591 [31%] cases and 1302 [69%] controls). The median age at liver transplantation was 53·7 years (IQR 47·3-59·0) for cases and 55·3 years (48·0 to 61·2) for controls. The median time interval between transplant and liver biopsy was 21 months (5 to 71). The weighted LSTM model (area under the curve 0·798 [95% CI 0·790 to 0·810]) consistently outperformed other methods, including unweighted LSTM (0·761 [0·750 to 0·769]; p=0·031) Recurrent Neural Network (0·736 [0·721 to 0·744]), Temporal Convolutional Networks (0·700 [0·662 to 0·747], and Random Forest 0·679 [0·652 to 0·707]), FIB-4 (0·650 [0·636 to 0·663]) and APRI (0·682 [0·671 to 0·694]) when diagnosing F2 or worse stage fibrosis. In a subgroup of patients with transient elastography results, weighted LSTM was not significantly better at detecting fibrosis (≥F2; 0·705 [0·687 to 0·724]) than transient elastography (0·685 [0·662 to 0·704]). The top ten variables predictive for significant fibrosis were recipient age, primary indication for transplantation, donor age, and longitudinal data for creatinine, alanine aminotransferase, aspartate aminotransferase, total bilirubin, platelets, white blood cell count, and weight.

INTERPRETATION

Deep learning algorithms, particularly weighted LSTM, outperform other routinely used non-invasive modalities and could help with the earlier diagnosis of graft fibrosis using longitudinal clinical and laboratory variables. The list of most important predictive variables for the development of fibrosis will enable clinicians to modify their management accordingly to prevent onset of graft cirrhosis.

FUNDING

Canadian Institute of Health Research, American Society of Transplantation, Toronto General and Western Hospital Foundation, and Paladin Labs.

Quantification of extracellular matrix remodeling for the non-invasive identification of graft fibrosis after liver transplantation

Detecting patients with early post-transplant fibrosis after liver transplantation (LT) is very important. Non-invasive tests are needed to avoid liver biopsies. We aimed to detect fibrosis in liver transplant recipients (LTR) using extracellular matrix (ECM) remodeling biomarkers. ECM biomarkers for type III (PRO-C3), IV (PRO-C4), VI (PRO-C6) and XVIII (PRO-C18L) collagen formation and type IV collagen degradation (C4M) were measured by ELISA in prospectively collected, cryopreserved plasma samples (n = 100) of LTR with paired liver biopsies from a protocol biopsy program. Fibrosis ≥ F2 was present in 29% of patients (median 44 months post-LT). APRI and FIB-4 neither identified significant fibrosis nor were correlated with histopathological fibrosis scores, while ECM biomarkers (AUCs 0.67-0.74) did. The median levels of PRO-C3 (15.7 vs. 11.6 ng/ml; p = 0.002) and C4M (22.9 vs. 11.6 ng/ml; p = 0.006) levels were elevated in T-cell-mediated rejection compared to normal graft function. The median levels of PRO-C4 (178.9 vs. 151.8 ng/ml; p = 0.009) and C4M (18.9 vs. 16.8 ng/ml; p = 0.004) levels were increased if donor-specific antibodies were present. PRO-C6 had the highest sensitivity (100%), NPV (100%) and negative likelihood-ratio (0) for graft fibrosis. To conclude, ECM biomarkers are helpful in identifying patients at risk of relevant graft fibrosis.

Main factors influencing long-term outcomes of liver transplantation in 2022

Liver transplant (LT) outcomes have markedly improved in the recent decades, even if long-term morbidity and mortality are still considerable. Most of late deaths are independent from graft function and different comorbidities, including complications of metabolic syndrome and de novo neoplasms, seem to play a key role in determining long-term outcomes in LT recipients. This review discusses the main factors associated with late mortality and suggests possible strategies to improve long-term management and follow-up after liver transplantation. In particular, the reduction of drug toxicity, the use of tools to identify high-risk patients, and setting up a multidisciplinary team also for long-term management of LT recipients may further improve survival after liver transplantation.

Inevitability of disease recurrence after liver transplantation for NAFLD cirrhosis

Background & Aims

Liver transplantation (LT) is the only available treatment for end-stage non-alcoholic fatty liver disease (NAFLD) (related decompensated cirrhosis and/or hepatocellular carcinoma). The aim of our study was to evaluate the risk of disease recurrence after LT and the factors influencing it.

Method

This retrospective multicenter study included adults transplanted for NAFLD cirrhosis between 2000 and 2019 in 20 participating French-speaking centers. Disease recurrence (steatosis, steatohepatitis and fibrosis) was diagnosed from liver graft biopsies.

Results

We analyzed 150 patients with at least one graft liver biopsy available ≥6 months after transplantation, among 361 patients transplanted for NAFLD. The median (IQR) age at LT was 61.3 (54.4-64.6) years. The median follow-up after LT was 4.7 (2.8-8.1) years. The cumulative recurrence rates of steatosis and steatohepatitis at 5 years were 80.0% and 60.3%, respectively. Significant risk factors for steatohepatitis recurrence in multivariate analysis were recipient age at LT <65 years (odds ratio [OR] 4.214; p = 0.044), high-density lipoprotein-cholesterol <1.15 mmol/L after LT (OR 3.463; p = 0.013) and grade ≥2 steatosis on the graft at 1 year after LT (OR 10.196; p = 0.001). The cumulative incidence of advanced fibrosis (F3-F4) was 20.0% at 5 years after LT and significant risk factors from multivariate analysis were metabolic syndrome before LT (OR 8.550; p = 0.038), long-term use of cyclosporine (OR 11.388; p = 0.031) and grade ≥2 steatosis at 1 year after LT (OR 10.720; p = 0.049). No re-LT was performed for NAFLD cirrhosis recurrence.

Conclusion

Our results strongly suggest that recurrence of initial disease after LT for NAFLD is inevitable and progressive in a large proportion of patients; the means to prevent it remain to be further evaluated.

Impact and implications

Non-alcoholic fatty liver disease (NAFLD) is a growing indication for liver transplantation, but the analysis of disease recurrence, based on graft liver biopsies, has been poorly studied. Cumulative incidences of steatosis, steatohepatitis and NAFLD-related significant fibrosis recurrence at 5 years were 85.0%, 60.3% and 48.0%, respectively. Grade ≥2 steatosis on graft biopsy at 1 year (present in 25% of patients) is highly predictive of recurrence of steatohepatitis and advanced fibrosis: bariatric surgery should be discussed in these patients specifically.

Minimal Development of Liver Fibrosis in Adult Tolerant Liver Transplant Recipients Late After Immunosuppressive Drug Weaning and Transplantation

BACKGROUND

Operationally tolerant liver transplant (LTx)-recipients can be weaned off immunosuppressive (IS) drugs without development of graft rejection. However, it is feared that liver fibrosis might develop after complete IS weaning. The purpose of this small single-center study was to assess liver fibrosis in adult tolerant LTx recipients long after LTx and IS weaning.

METHODS

Liver fibrosis was assessed in adult tolerant LTx-recipients (n = 9) using noninvasive transient elastography and measurements of multiple pro- and antifibrotic serum markers associated with liver fibrosis. The data was collected for 2 subsequent years; 8 and 9 years after IS weaning and 19 and 20 years after transplantation. Healthy individuals (n = 9) matched for age and sex were included as a reference for fibrosis-related serum markers. This study was conducted in accordance with the Declaration of Helsinki and approved by the medical ethics committee of our institution.

RESULTS

Transient elastography indicated that 7 of 9 tolerant LTx recipients had no or minimal liver fibrosis (F0-F1), whereas 2 recipients had moderate or severe liver fibrosis (F2-F3). Most fibrosis-related serum markers in tolerant LTx recipients were within or close to the range obtained for healthy individuals.

CONCLUSIONS

The results from this small, single-center study indicated that most adult tolerant LTx recipients have no or minimal liver graft fibrosis long after transplantation and IS weaning, and their fibrosis-related serum marker profile indicates an absence of a profibrotic status.

Nonalcoholic Fatty Liver Disease in Living Donor Liver Transplant Recipients: A Histology-Based Study

Background

Recurrent or de novo nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are common after liver transplantation (LT) and may be associated with rapid progression to fibrosis; however, there is limited data in this regard after living donor liver transplantation (LDLT).

Material and methods

This is a retrospective study at a high volume LDLT center of all liver biopsies performed in patients with post-transplant NAFLD diagnosed on ultrasound of the abdomen. Liver biopsy was indicated for raised transaminases and/or high liver stiffness on TE. The association between these prebiopsy parameters and inflammation and fibrosis on histology was analyzed. Data are shown as mean ± standard deviation or median (25-75 interquartile range).

Results

The study cohort consisted of 31 males and 3 females, aged 43 ± 10 years. The LT to liver biopsy interval was 44 (28-68) months. The prebiopsy AST and ALT were 71 (38-119) and 66 (50-156), respectively. The histology suggested no nonalcoholic steatohepatitis (NASH) in 7 (20%), borderline NASH in 15 (44%), and NASH in 12 (35%) patients. A total of 15 patients (44%) had stage 1 or stage 2 fibrosis. The proportion of patients having fibrosis was significantly higher in patients with NASH (83%) compared to patients with borderline NASH (33%) or no NASH (none had fibrosis, P = 0.001). Among 18 patients who underwent TE (on FibroScan), liver stiffness was significantly higher in patients with fibrosis [18.1 (9.7-22.5)] than in those without fibrosis [9.7 (4.0-12.7); P = 0.043].

Conclusion

Over a third of the LDLT recipients with post-transplant NAFLD developed NASH, and nearly half, borderline NASH 3-5 years after transplant. Most with established NASH also had fibrosis on histology. Prevention of risk factors and early diagnosis is warranted in these patients.

A Diagnostic Test Meta-Analysis Evaluating Imaging-Based and Blood Biomarker-Based Assessment Tools for Fibrosis After Liver Transplantation

Early detection of liver graft fibrosis is crucial for risk stratification to identify patients for liver biopsy and timely treatment. However, diagnostic accuracy of noninvasive tests (NITs) remains unclear. Thus, this study sought to evaluate diagnostic accuracy of NITs in assessing liver allograft fibrosis and compare the differences in specificities and sensitivities among NITs. Medline and Embase databases were searched to include articles on diagnostic tests in liver transplantation (LT) patients with fibrosis. A meta-analysis on diagnostic test accuracy was conducted in a random-effects model. Sensitivities and specificities among the diagnostic tests were compared, and threshold values were calculated where applicable. A total of 25 articles were included. Vibration-controlled transient elastography (VCTE) met the minimum diagnostic accuracy requirements, yielding sensitivity, specificity, and diagnostic odds ratios of 0.9 (CI, 0.8-1.0), 0.9 (CI, 0.8-1.0), and 379.6 (CI, 45.8-1728.7), respectively. In the threshold assessment, the optimal cutoff was 9.30 kPa with a sensitivity, specificity, and area under the curve of 0.7 (CI, 0.5-0.9), 0.9 (CI, 0.8-0.9), and 0.9 (CI, 0.8-0.9), respectively. For significant fibrosis, acoustic radiation force impulse (ARFI) was superior to FibroTest (LabCorp [Burlington, NC]) and magnetic resonance elastography (MRE) in sensitivity. VCTE was superior to FibroTest in specificity. For advanced fibrosis, ARFI was superior to the Fibrosis-4 Index (FIB-4) in sensitivity. VCTE was superior to the AST to Platelet Ratio Index (APRI), MRE, and FIB-4 in specificity. In cirrhosis, VCTE was superior to APRI in specificity (P = 0.004) with comparable sensitivity. This study demonstrates the potential of VCTE and ARFI as diagnostic tools for fibrosis in LT recipients compared with blood-based NITs, which were shown to be less optimal.

Assessment of Liver Fibrosis with the Use of Elastography in Paediatric Patients with Diagnosed Cystic Fibrosis

Background

Complications of cystic fibrosis-associated liver disease (CFLD) are a leading nonpulmonary cause of death. Noninvasive tests enabling early detection of liver changes, especially in children are sought. The aim of the study was to assess the scale of liver fibrosis with the use of elastography in paediatric patients with diagnosed cystic fibrosis (CF) and its comparison with other tests (APRI and Fibrotest).

Methods

We examined 41 children, in the age range 2-21 years, with diagnosed CF. The analysis a included clinical picture, laboratory parameters of liver damage, and cholestasis. Aspartate aminotransferase-to-platelet ratio index (APRI) and Fibrotest were done in all patients. Liver stiffness measurements were acquired using shear-wave elastography (SWE).

Results

CFLD was diagnosed in 16/41 patients (39%). Abnormal elastography was observed in 19/41 patients (46.3%), and in 5/41 (12.2%), the changes were advanced (F4). Abnormal elastography was observed in 12/16 (75%) of the patients with CFLD, and in 7/25 (28%), there were no lesions observed in the liver in the course of cystic fibrosis. In all patients with F4, we observed abnormal results of the APRI and Fibrotest. In most patients with small changes in elastography, we found normal results of the APRI and Fibrotest.

Conclusion

Elastography seems to be a noninvasive examination useful in everyday clinical work in detecting early liver changes and monitoring of progression in paediatric patients with diagnosed cystic fibrosis, ahead of changes in laboratory tests. The cost-effectiveness of this test, the possibility of its repetition, and its availability are additional benefits.

De novo and recurrence of metabolic dysfunction-associated fatty liver disease after liver transplantation

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a new acronym adopted from the consensus of international experts. Given the increasing prevalence of MAFLD in pre-transplant settings, de novo and recurrent graft steatosis/MAFLD are common in post-transplant settings. The impact of graft steatosis on long-term outcomes is unclear. The current knowledge of incidence rate, risk factors, diagnosis, long-term outcomes, and management of graft steatosis (both de novo and recurrent) is discussed in this review.

Nonalcoholic Fatty Liver Disease after Liver Transplant

Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease in the world. The rising prevalence of nonalcoholic steatohepatitis (NASH) has led to a 170% increase in NASH cirrhosis as the listing indication for liver transplantation from 2004 to 2013. As of 2018, NASH has overtaken hepatitis C as an indication for liver transplantation in the USA. After liver transplantation, the allograft often develops recurrent NAFLD among patients with known NASH cirrhosis. In addition to recurrent disease, de novo NAFLD has been reported in patients with other indications for liver transplantation. In this review, we will discuss the risk factors associated with recurrent and de novo NAFLD, natural course of the disease, and management strategies after liver transplantation.

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.

Usefulness of Controlled Attenuation Parameter and Liver Stiffness Measurement for the Identification of Extended-criteria Donors and Risk-assessment in Liver Transplantation

BACKGROUND

Controlled attenuation parameter (CAP) and liver stiffness measurement (LSM) are noninvasive surrogates for hepatic steatosis and fibrosis, respectively, and could help identify extended criteria donors in liver transplantation (LT). We aimed to determine the accuracy of CAP/LSM in deceased donors along with post-LT changes.

METHODS

Accuracy of preprocurement CAP/LSM to grade/stage steatosis/fibrosis was determined using liver biopsy as reference. Transplant outcomes, including primary nonfunction (PNF) and early allograft dysfunction (EAD), were recorded. Recipients underwent CAP/LSM as outpatients. Areas under the receiver operating characteristic curve (AUROC) and regression models were constructed to analyze data.

RESULTS

We prospectively evaluated 160 allografts (138 transplanted). Same-probe paired baseline/post-LT CAP was 231 dB/m (181-277) / 225 (187-261) (p=0.61), and LSM 7.6 kPa (6.3-10.8) / 5.9 (4.6-8.7) (p=0.002), respectively. CAP reading was affected by BMI and LSM by ALT, race and bilirubin. Although CAP did not correlate with steatosis from frozen sections (rho=0.08; p=0.47), it correlated with steatosis from permanent sections (rho=0.32; p<0.001) and with oil red O histomorphometry (rho=0.35, p=0.001). CAP identified moderate-to-severe steatosis with an AUROC curve of 0.79 (0.66-0.91), for a negative predictive value of 100% at a cutoff value of 230 dB/m. LSM correlated with fibrosis staging (rho=0.22, p=0.007) and it identified discarded allografts with advanced fibrosis/cirrhosis. Patients with no to minimal fibrosis had an LSM of 7.6 (6-10.1) kPa.

CONCLUSIONS

Our results are proof-of-concept of the utility of CAP/LSM during organ procurement. Establishing the precise role of these noninvasive tools in the organ allocation process mandates confirmatory studies.

Diagnostic Performance of Vibration-Controlled Transient Elastography in Liver Transplant Recipients

BACKGROUND & AIMS

Vibration-controlled transient elastography (VCTE) is a non-invasive tool for detecting hepatic steatosis and fibrosis in patients who have not received liver transplants. We aimed to evaluate the diagnostic performance of VCTE in detection of hepatic steatosis and fibrosis in patients who have undergone liver transplantation.

METHODS

We performed a prospective study of 99 liver transplant recipients assessed by VCTE using a standard protocol. Controlled attenuation parameter cutoff values for pairwise steatosis grade and liver stiffness measurements (LSM) and cutoff values for pairwise fibrosis stage were determined using cross-validated area under the receiver operating characteristics (AUROC) curve analyses. We calculated sensitivity (fixed at 90%) and specificity (fixed at 90%) values.

RESULTS

A controlled attenuation parameter cutoff value of 270 dB/m detected any hepatic steatosis with an AUROC of 0.88 (95% CI, 0.78-0.93). VCTE detected steatosis grades 2-3 vs 0-1 with an AUROC of 0.94 (95% CI, 0.89-0.99) and steatosis grade 3 vs 0-2 was similar and AUROC of 0.89 (95% CI, 0.83-0.96). When we used an LSM cutoff value of 10.5 kPa, VCTE identified patients with advanced fibrosis (fibrosis stages ≥ 3) with an AUROC of 0.94 (95% CI, 0.88-0.99). At fixed sensitivity, the cutoff LSM value of 10.5k Pa excluded advanced fibrosis with a negative predictive value of 0.99. At fixed specificity, the cutoff LSM value of 16.9 kPa detected advanced fibrosis with a sensitivity of 0.86, a positive predictive value (PPV) of 0.40, and a negative predictive value of 0.99.

CONCLUSIONS

VCTE accurately detects hepatic steatosis and fibrosis in recipients of liver transplants. This non-invasive method might be used to identify patients in need of confirmatory liver biopsy analysis.

Evaluation of Graft Fibrosis, Inflammation and Donor-specific Antibodies at Protocol Liver Biopsies in Pediatric Liver Transplant Patients: a Single Center Experience

BACKGROUND

The impact of graft fibrosis and inflammation on the natural history of pediatric liver transplants (LT) is still debated. Our objectives were to evaluate the evolution of posttransplant fibrosis and inflammation over time at protocol liver biopsies (PLBs), risk factors for fibrosis, presence of donor-specific antibodies (DSAs) and/or their correlation with graft and recipient factors.

METHODS

A single-center, retrospective (2000-2019) cross-sectional study on pediatric LT recipients who had at least one PLB, followed by a longitudinal evaluation in those who had at least two PLBs, was conducted. Fibrosis was assessed by the Liver Allograft Fibrosis Semiquantitative score, inflammation by the Rejection Activity Index, DSAs by Luminex®.

RESULTS

A total of 134 PLBs from 94 patients were included. Fibrosis was detected in 87% (30% mild, 45% moderate, 12% severe), 80% in the portal tracts. There was an increase in fibrosis between the 1-3 and the 4-6 year group (p=0.01), then it was stable. Inflammation was observed in 44% (30% mild, 13% moderate, 1% severe), 90% in the portal tracts. Anti-HLA II (IgG) DSAs were detected in 14/40 (35%). Portal fibrosis was associated with portal inflammation in the 1-3 year group (p=0.04). Low immunosuppression levels were correlated with sinusoidal fibrosis (p=0.04) and DSA positivity (p-value=0.006). There was no statistically significant correlation between DSA positivity and the presence of graft fibrosis or inflammation.

CONCLUSIONS

This study corroborates the concept of an early evolution of silent graft fibrosis. Suboptimal immunosuppression may play a role in the development of fibrosis and DSAs.

Determination of allograft fibrosis by measurement of liver stiffness using transient elastography in children after liver transplantation at Shiraz Organ Transplant Center

AIM

The aim of this study was to determine allograft fibrosis by measuring LS using TE in children after liver transplantation at Shiraz Organ Transplant Center.

BACKGROUND

Liver stiffness (LS) assessment using fibro-scanning (transient elastography-TE) is a non-invasive method for evaluating liver fibrosis.

METHODS

All children undergoing liver transplant from 2012 to 2016 were included in the study. Data on demographics, graft types, immunosuppressive drugs, as well as clinical and paraclinical data were obtained from patients' records. TE was performed to determine LS in all patients. Liver fibrosis was also confirmed based on Metavir score.

RESULTS

During this period, more than 400 liver Tx were done in children, but only 54 patients, comprising 20 (37%) girls and 34 (63%) boys who underwent liver transplantation, were available and willing to participate in this study. The mean age of the patients was 12.96 ± 5.32 years. Correlations between FS score (LS) and AST (p = 0.01), total bilirubin (p = 0.002), albumin (p = 0.001), PT (p = 0.03), and INR (p = 0.001) were significant. There was no significant relationship between FS score (LS) and type of allograft (p = 0.79) and underlying disease (p = 0.36). Positive and significant correlations were observed between Metavir score and AST (p = 0.01), total bilirubin (p = 0.01), INR (p = 0.004), and cholesterol (p = 0.001). The severity of fibrosis significantly and negatively correlated with albumin (p = 0.004) and glucose (p = 0.003). Also, there was no significant relationship between Metavir score and allograft type (p = 0.7).

CONCLUSION

The current study demonstrated that 14.9% of LT patients had a METAVIR ≥ F2. The time between LT and TE was significantly correlated with LS and the degree of liver fibrosis based on Metavir score. However, there was no significant relationship between LS with allograft type or underlying liver disease.

Serum Mac-2 binding protein glycosylation isomer as a biomarker of fibrosis in living donor liver transplant graft

INTRODUCTION

Non-invasive assessment of graft fibrosis is important in liver transplantation. Mac-2 binding protein glycosylation isomer (M2BPGi) has been reported as a diagnostic marker for this purpose, and thus, this predictive ability of M2BPGi was assessed in this study.

PATIENTS AND METHODS

In this retrospective study, 236 patients who received living donor liver transplantation (LDLT) from August 1997 to March 2017 were enrolled. Among them, 94 biopsy patients were analyzed. Further, the predictive ability of fibrotic biopsy using M2BPGi, Fibroscan, and Fib-4 index was compared.

RESULTS

Of 94 LDLT patients (53 men, 41 women), the median ages of recipients and donors were 57.5 and 33.0 years, respectively. The median M2BPGi values in patients with F0 (n = 11), F1 (n = 38), F2 (n = 35), and F3/4 (n = 10) were 0.680, 0.760, 1.240, and 4.110 COI, respectively. There were significant correlations between the fibrotic stage and M2BPGi levels (Kruskal-Wallis test, P < .0001). The area under the ROC curve for the diagnosis of F ≥ 2 in M2BPGi was 0.778, which was superior to Fibroscan (0.701) and Fib-4 index (0.639).

CONCLUSION

M2BPGi is an accurate, non-invasive detection method for significant fibrosis after LDLT.

Diagnostic performance of non-invasive tests for evaluation of hepatic graft fibrosis in pediatric liver transplantation: A scoping review

BACKGROUND

Hepatic graft fibrosis is a common histologic finding of pediatric liver transplant (LT) that might affect long-term graft outcome. However, its diagnosis and staging require an invasive liver biopsy.

AIM

To review the published literature on the diagnostic accuracy of elastography and serum-based fibrosis markers for assessing hepatic graft fibrosis in pediatric LT recipients.

METHODS

A scoping review was conducted using a systematic search of published literature in PubMed (MEDLINE), EMBASE, SCOPUS, and Cochrane Library between 2002 and 2019. We included all English conference abstracts or full-text articles that examined the diagnostic accuracy of the non-invasive test(s) to assess hepatic fibrosis in LT children, using liver biopsy as the reference test.

RESULTS

Eight studies were included, of which 6 examined transient elastography (TE), one investigated acoustic radiation force impulse elastography, and 5 examined serum-based fibrosis markers (AST/ALT ratio, AST-to-platelet ratio index, FibroTest, enhanced liver fibrosis test). TE reportedly had a good AUROC (range: 0.82-0.92) to distinguish children with hepatic graft fibrosis (≥F1) from those with no fibrosis. However, there was considerable overlap of liver stiffness cutoffs in the mild to significant fibrosis groups (≥F1 and ≥F2). Current serum-based fibrosis markers reportedly had an unsatisfactory diagnostic accuracy.

CONCLUSIONS

TE in LT children has similar diagnostic value and limitations as in the non-transplant setting. Prospective studies are warranted to validate an optimal liver stiffness cutoff for predicting significant hepatic graft fibrosis (≥F2) and to determine if a meaningful change in liver stiffness from baseline could identify patients at risk for fibrosis progression.

Elevated liver stiffness without histological evidence of liver fibrosis in rural Ugandans

Liver fibrosis may be assessed noninvasively with transient electrography (TE). Data on the performance of TE for detecting liver fibrosis in sub-Saharan Africa are limited. We evaluated the diagnostic accuracy of TE by performing liver biopsies on persons with liver fibrosis indicated by TE. We enrolled HIV-infected and HIV-uninfected participants with TE scores consistent with at least minimal disease (liver stiffness measurement [LSM]≥7.1 kPa). Biopsies were performed and staged using the Ishak scoring system. A concordant result was defined using accepted thresholds for significant fibrosis by TE (LSM ≥ 9.3 kPa) and liver biopsy (Ishak score ≥ 2). We used modified Poisson regression methods to quantify the univariate and adjusted prevalence risk ratios (PRR) of the association between covariates and the concordance status of TE and liver biopsy in defining the presence of liver fibrosis. Of 131 participants with valid liver biopsy and TE data, only 5 participants (3.8%) had Ishak score ≥ 2 of whom 4 had LSM ≥ 9.3 kPa (sensitivity = 80%); of the 126 (96.2%) with Ishak score < 2, 76 had LSM < 9.3 kPa (specificity = 61%). In multivariable analysis, discordance was associated with female gender (adjPRR = 1.80, 95%CI 1.1-2.9; P = .019), herbal medicine use (adjPRR 1.64, 95% CI = 1.0-2.5; P = .022), exposure to lake or river water (adjPRR 2.05, 95% CI = 1.1-3.7; P = .016), and current smoking (adjPRR 1.72, 95%CI 1.0-2.9; P = .045). These data suggest that TE among rural Ugandans has low specificity for detection of histologically confirmed liver fibrosis. Caution should be exercised when using this tool to confirm significant liver fibrosis.

A New Visual Transient Elastography Technique for Grading Liver Fibrosis in Patients With Chronic Hepatitis B

ABSTRACT

Liver fibrosis is evaluated to assess the prognosis and guide the treatment of chronic hepatitis B (CHB). To compare the efficiency of 2 transient elastography techniques for grading liver fibrosis in CHB: visual transient elastography (ViTE) with real-time image guidance and FibroScan (FS) with no image guidance. All of the CHB patients in this study underwent both FS and ViTE examinations. The final diagnosis was based on the histological findings of a liver biopsy. According to the severity of liver fibrosis (based on the Scheuer criteria), the area under the receiver operating characteristic curve values for diagnostic efficiency were calculated for the 2 elastography techniques. This study enrolled 227 patients (79 [39.1%] women; mean age, 45.8 ± 16.8 years). The ViTE and FS liver elasticity measurements were highly correlated with liver fibrosis stage (r = 0.852 and r = 0.813, respectively). The area under the receiver operating characteristic curve value was larger for ViTE compared with FS, with respect to differentiating liver fibrosis stage, but not significantly (P > 0.05). The ViTE and FS can be used to detect and stage liver fibrosis. ViTE, easier and quicker to perform with superior interoperator reproducibility, is a stable and reliable elastography technique that benefits from real-time visual guidance.

Non-invasive screening for subclinical liver graft injury in adults via donor-specific anti-HLA antibodies

The majority of liver grafts exhibit abnormal histological findings late after transplantation, even when liver enzymes are normal. Such subclinical graft injuries were associated with rejection and fibrosis progression in recent studies. The identification of non-invasive biomarkers for subclinical graft injury might help to individualize immunosuppression. Therefore, graft injury was assessed in 133 liver biopsies with normal/near normal liver enzymes from a prospective liver biopsy program. Cytokeratin-18 cell death marker (M65) and donor specific anti-HLA antibodies (DSA) were measured as non-invasive markers in paired plasma samples in addition to routine parameters. M65 was associated with subclinical graft injury but this association was too weak for reasonable clinical application. DSA positivity was associated with more graft inflammation (OR = 5.4) and more fibrosis (OR = 4.2). Absence of DSA excluded fibrosis in 87–89%, while presence of DSA excluded histological criteria for immunosuppression minimization attempts in 92–97%. While CK18 cell death marker had no diagnostic value for the detection of subclinical liver graft injury, DSA testing can help to preselect patients for immunosuppression reduction in case of DSA negativity, while DSA positivity should prompt elastography or liver biopsy for the assessment of subclinical graft injury.

Efficient and targeted chemo-gene delivery with self-assembled fluoro-nanoparticles for liver fibrosis therapy and recurrence

The treatment options of liver fibrosis remain limited except for liver transplantation due to the complexity and slow development in its progression. Besides, liver fibrosis recurrence and intervention time have not been reported as significant indicators to affect the anti-fibrotic efficacy of tested drugs/strategies. Herein, a novel fluoropolymer is developed to achieve high drug loading of sorafenib and efficient delivery of miR155 inhibitor (anti-miR155) for dual-targeting of hepatic stellate cells (HSCs) and kupffer cells (KCs), and we report a detailed plan on the design of treatment regimen to reveal the relationship between chemogene therapy, intervention time and fibrosis recurrence. Such a combined chemo-gene therapy of sorafenib and anti-miR155 can achieve superior therapeutic efficiency by polarizing the pro-inflammatory M1 to anti-inflammatory M2 of KCs and inhibiting the proliferation of HSCs. Importantly, efficacy and recurrence prevention of chemogene therapy earlier in the liver fibrosis will be more effective than the treatment at later stage. In conclusion, this work proposes a novel strategy to improve the efficacy and prevent recurrence of liver fibrosis by dual-regulating of KCs and HSCs, and emphasizes the importance of therapy earlier in the treatment of liver fibrosis.

The Utility of Assessing Liver Allograft Fibrosis and Steatosis Post-Liver Transplantation Using Transient Elastography With Controlled Attenuation Parameter

AIM

Allograft steatosis is an emerging concern after liver transplantation (LT). The use of transient elastography (TE) with controlled attenuation parameter (CAP) may facilitate early detection of and intervention for allograft steatosis. This study aimed to evaluate the prevalence and risk factors of allograft steatosis using TE and CAP.

METHODS

The presence of steatosis and severe steatosis were defined by CAP ≥222 and ≥290 dB/m, respectively. Demographics and clinical characteristics were compared between patients with and without severe steatosis. Regression analyses were performed to determine factors associated with severe steatosis.

RESULTS

Of 150 patients, 105 (70%) had steatosis while 40% of these had severe steatosis. Thirty-four (81.0%) patients with severe steatosis had normal alanine transaminase at the time of TE. In multivariable analyses, age at LT (odds ratio [OR] 1.05, 95% confidence interval [CI] 1.01-1.08), post-LT obesity (OR 5.34, 95% CI 1.53-18.65), and alcoholic liver disease (OR 12.86, 95% CI 2.24-73.74) were significant predictors of severe steatosis. Five patients underwent liver biopsies as a result of advance fibrosis seen on TE and were later diagnosed with chronic allograft rejection. Two of these patients had normal liver chemistries, and the remaining 3 had mild elevation of alkaline phosphatase.

CONCLUSION

Steatosis was present in 70% of patients who underwent TE after LT. Advanced age at LT, post-LT obesity, and alcoholic liver disease were significant predictors for severe steatosis. The majority of patients with severe steatosis had normal liver enzymes. TE should be considered as a screening modality for allograft steatosis and fibrosis even when liver chemistries are normal.

Assessment of Selected Parameters of Liver Fibrosis and Inflammation in Patients with Diagnosed Cystic Fibrosis

Changes in the liver and bile ducts observed in patients diagnosed with cystic fibrosis result from inflammatory processes as well as fibrosis, remodeling, apoptosis, and cholestasis. As a consequence, portal hypertension, cirrhosis, and hepatic failure may develop. So far, the complexity of these processes has not been elucidated. Study Objectives. The aim of the study was to evaluate the selected parameters of hepatitis and fibrosis (Fibrotest, Actitest, and APRI) in patients diagnosed with cystic fibrosis. Material and Methods. The study included 79 patients with cystic fibrosis, aged 1 to 20 years (mean age 9.8 years), 49 girls (62%) and 30 boys (38%). The analysis involved the following: age, sex, clinical manifestations, laboratory tests evaluating pancreas function, parameters of liver damage, and cholestasis. Fibrotest, Actitest, and APRI were performed in all subjects. Results. Elevated parameters of hepatic cell damage (hypertransaminasemia) were found in 31/79 (39.2%) patients, while abnormal cholestasis parameters in 21/79 (26.6%). The abnormal results of Fibrotest were reported in 15% of patients (12/79), while of Actitest in 10% (8/79). In contrast, elevated APRI values were found in only 7.6% (6/79) of subjects. There was a statistically significant correlation between APRI and age (higher values were observed in younger children) and between Fibrotest and Actitest and pancreatic insufficiency (higher values were found in subjects without this abnormality). Moreover, Fibrotest values were significantly higher in girls. There was no correlation between Fibrotest, Actitest, and APRI values and the type of mutation. Conclusion. It appears that Fibrotest may be used as an early marker of liver fibrosis in patients with cystic fibrosis. Increased APRI values were only found in subjects with advanced hepatic lesions, most often in the form of portal hypertension.

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.

The Reliability of Fibro-test in Staging Orthotopic Liver Transplant Recipients with Recurrent Hepatitis C

Background and Aims: Liver biopsy remains the gold standard for staging of chronic liver disease following orthotopic liver transplantation. Noninvasive assessment of fibrosis with Fibro-test (FT) is well-studied in immunocompetent populations with chronic hepatitis C virus infection. The aim of this study is to investigate the diagnostic value of FT in the assessment of hepatic fibrosis in the allografts of liver transplant recipients with evidence of recurrent hepatitis C. Methods: We retrospectively compared liver biopsies and FT performed within a median of 1 month of each other in orthotopic liver transplantation recipients with recurrent hepatitis C. Results: The study population comprised 22 patients, most of them male (19/22), and with median age of 62 years. For all patients, there was at least a one-stage difference in fibrosis as assessed by liver biopsy compared to FT, while for the majority (16/22) there was at least a two-stage difference. The absence of correlation between the two modalities was statistically demonstrated (Mann-Whitney U test, p = 0.01). In detecting significant fibrosis (a METAVIR stage of F2 and above), an FT cut-off of 0.5 showed moderate sensitivity (77%) and negative predictive value (80%), but suboptimal specificity (61%) and positive predictive value (58%). Conclusions: In post-transplant patients with recurrent hepatitis C, FT appears to be inaccurately assessing the degree of allograft fibrosis, therefore limiting its reliability as a staging tool.

TIM-4 interference in Kupffer cells against CCL4-induced liver fibrosis by mediating Akt1/Mitophagy signalling pathway

OBJECTIVES

T-cell immunoglobulin domain and mucin domain-4 (TIM-4) is selectively expressed on antigen-presenting cells (APCs) and modulates various immune responses. However, the role of TIM-4 expressed by Kupffer cells (KCs) in liver fibrosis remains unclear. The present study aimed to explore whether and how TIM-4 expressed by KCs is involved in liver fibrosis.

MATERIALS AND METHODS

Mice chronic liver fibrosis models were established and divided into the olive-induced control group, CCL4-induced control group, olive-induced TIM-4 interference group and CCL4-induced TIM-4 interference group. Different techniques were used to monitor the fibrotic effects of TIM-4, including histopathological assays, Western blotting, ELISA and transmission electron microscopy. Additionally, mice liver transplant models were established to determine the fibrotic effects of TIM-4 on fibrosis after liver transplantation (LT).

RESULTS

We found that the induction of liver fibrosis by CCL4 was associated with TIM-4 expression in KCs. TIM-4 interference essentially contributed to liver fibrosis resolution. KCs from the TIM-4 interference group had decreased levels of pro-fibrotic markers, reduced TGF-β1 secretion and inhibited hepatic stellate cell (HSC) differentiation into myofibroblast-like cells. In addition, we used GdCl3 to verify that KCs are the primary source of TGF-β1 during fibrosis progression. Moreover, KCs from CCL4-induced mice showed increased ROS production, mitophagy activation and TGF-β1 secretion. However, TIM-4 interference in the KCs inhibited Akt1-mediated ROS production, resulting in the suppression of PINK1, Parkin and LC3-II/I activation and the reduction of TGF-β1 secretion during liver fibrosis. Additionally, TIM-4 interference potentially attenuated development of fibrosis after LT.

CONCLUSIONS

Our findings revealed the underlying mechanisms of TIM-4 interference in KCs to mitigate liver fibrosis.

A review of the use of transient elastography in the assessment of fibrosis and steatosis in the post-liver transplant patient

Liver biopsy is considered the gold standard method for diagnosing and staging liver disease, particularly in the post-liver transplant setting. Given the invasive nature of biopsy, alternate means for accurately assessing liver fibrosis and steatosis are preferred especially as the number of patients with fatty liver disease is increasing. Transient elastography has been validated as a useful tool for evaluation of liver fibrosis, as has controlled attenuation parameter index as a tool for assessing steatosis. It is a non-invasive, rapid, and highly reproducible approach to demonstrate the presence of fibrosis among non-transplant patients with chronic liver disease of various etiologies. However, it has not yet found wide acceptance in liver transplant recipients. There are few published studies evaluating the merits and applicability of transient elastography to assess allografts after liver transplantation. We review the published data on the use of transient elastography with concurrent controlled attenuation parameter in liver transplant recipients and recommend its greater use to follow allograft function over time.

Liver Graft and Spleen Elastography After Living Liver Transplantation: Our First Results

AIM OF THE STUDY

Liver transplantation is widely applied as a standard and effective management of end-stage liver diseases, hepatocellular carcinoma, and acute liver failure. Investigation of morphologic and functional changes in the transplanted graft, gastrointestinal system, and spleen after transplantation is an important ground for assessment of post-transplantation results, early changes related to complications, and evaluation of response to treatment modalities. The aim of this study was to investigate the dynamics of changes in elastography of the liver graft and spleen after living-related liver transplantation.

MATERIAL AND METHODS

The study included 14 cirrhotic patients after living-related liver graft transplantation. Stiffness of the spleen and liver was evaluated before transplantation and at 1, 3, and 6 months after transplantation with a Supersonic Aixplorer Multi Wave device. Each procedure consisted of measuring the density in 10 points (spots) of the organ. The final result was calculated as the mean value of successful measurements (must have been > 60% of all measurements) and expressed in kilopascals.

RESULTS

The mean value of the liver and spleen stiffness before transplantation was 27 kPa (14-31 kPa) and 51 kPa (38-92 kPa), respectively. The stiffness of the spleen gradually reduced after transplantation to 40.3, 35.4, and 24.1 kPa (P = .001) at 1, 3, and 6 months. The stiffness of the liver graft in patients without complications was stable at 4-5 kPa, whereas the same value in patients with complications was increased (≥ 7.5 kPa). In 5 patients, endoscopic investigation confirmed the significant reduction of varicose veins after surgery.

CONCLUSION

Elastography of the liver graft and spleen after liver transplantation can be recommended as a useful-for-patient 1-off method of investigation.

Quantitative Ultrasound in Ex Vivo Fibrotic Rabbit Livers

Liver fibrosis is the common result of chronic liver disease. Diagnosis and grading liver fibrosis for patient management is mainly based on blood tests and hepatic puncture-biopsy, which is particularly invasive. Quantitative ultrasound (QUS) techniques provide insight into tissue microstructure and are based on the frequency-based analysis of the signals from biologic tissues. This study aims to quantify how spectral-based QUS parameters change with fibrosis grade. The changes in QUS parameters of healthy and fibrotic rabbit liver samples were investigated and were compared with the changes in liver stiffness, using shear wave elastography. Overall, the acoustic concentration was found to decrease with increasing fibrosis grade, and the effective scatterer size was found to be higher in fibrotic livers when compared with normal liver. The result of this study indicates that the combination of three QUS parameters (stiffness, effective scatterer size and acoustic concentration) provides the best classification performance, especially for classifying healthy and fibrotic livers.

Management of Recurrent and De Novo NAFLD/NASH After Liver Transplantation

Nonalcoholic steatohepatitis (NASH) is a growing indication for liver transplant whether the primary or secondary cause of liver disease, and it is expected to be the leading indication in the years to come. Nonalcoholic steatohepatitis recurs after transplant but the impact of the recurrence on allograft and patient outcomes is unclear. A group of multidisciplinary transplant practice providers convened at the International Liver Transplantation Society NASH consensus conference with the purpose of determining the current knowledge and future directions for understanding the recurrence rates, risk and management of NASH in the transplant allograft. Specific questions relating to posttransplant NASH were proposed and reviewed in detail with recommendations on future actions to fill the knowledge gaps.