Use of fatty donor liver is associated with diminished early patient and graft survival

Comprehensive Evaluation of Human Donor Liver Viability with Polarization-Sensitive Optical Coherence Tomography

Human liver transplantation is severely constrained by a critical shortage of donor livers, with approximately one quarter of patients on the waiting list dying due to the scarcity of viable organs. Current liver viability assessments, which rely on invasive pathological methods, are hampered by limited sampling from biopsies, particularly in marginal livers from extended criteria donors (ECD) intended to expand the donor pool. Consequently, there is a pressing need for more comprehensive and non-invasive evaluation techniques to meet the escalating demand for liver transplants. In this study, we propose the use of polarization-sensitive optical coherence tomography (PS-OCT) to perform a thorough viability evaluation across the entire surface of donor livers. PS-OCT imaging was conducted on multiple regions, achieving near-complete coverage of the liver surface, and the findings were cross-validated with histopathological evaluations. The analysis of hepatic parameters derived from pathology highlighted tissue heterogeneity. Leveraging machine learning and texture analysis, we quantified hepatic steatosis, fibrosis, inflammation, and necrosis, and established strong correlations (≥ 80%) between PS-OCT quantifications and pathological assessments. PS-OCT offers a non-invasive assessment of liver viability by quantifying hepatic parenchymal parameters across the entire donor liver, significantly complementing current pathological analysis. These results suggest that PS-OCT provides a robust, non-invasive approach to assessing donor liver viability, which could potentially decrease the discard rate of higher risk livers, thereby expanding the donor pool and reducing the inadvertent use of those livers unsuitable for transplantation.

Effects of Desflurane versus sevoflurane on graft outcome of patients with cirrhosis receiving steatotic liver graft in deceased donor liver transplantation

STUDY OBJECTIVE

This study aimed to analyze the effects of two volatile anesthetic agents, desflurane and sevoflurane, on graft outcomes in patients undergoing deceased donor liver transplantation (DDLT) for cirrhosis, with a specific focus on fatty grafts.

DESIGN

A retrospective observational study.

SETTING

A tertiary hospital (Severance Hospital, Korea).

PATIENTS

This study included 151 patients with liver cirrhosis who underwent DDLT for cirrhosis between January 2006 and December 2022.

INTERVENTIONS

Patients were grouped according to maintenance anesthesia received (desflurane or sevoflurane), the model for end-stage liver disease (MELD) score, and macrovesicular steatosis (MVS) of the liver graft.

MEASUREMENTS

Survival curves were constructed from the date of surgery to graft failure or death. After propensity score matching (PSM), Cox regression analysis was used to compare hazards ratios (HR) for 5-year graft and overall survival. Subgroup analyses were performed for the MELD score and MVS of the liver graft. Incidences of 1-month acute rejection and early allograft dysfunction (EAD) were also compared between the two groups.

MAIN RESULTS

Among 151 eligible patients, 49 patients remained in each group after PSM, with 14 (28.6 %) graft failures and deaths occurring in each group. In matched analysis, sevoflurane showed poorer 5-year graft and overall survival compared to desflurane in recipients of graft with ≥10 % MVS, and this trend was significant in patients with MELD score of ≥35. In Cox regression model, compared to desflurane sevoflurane showed a propensity score-matched HR of 5.8 (95 % CI, 1.13-30.50 for both 5-year graft and overall survival. Additionally, sevoflurane showed an increased risk of 1-month acute rejection; however, no difference was observed for EAD.

CONCLUSIONS

Sevoflurane as a maintenance agent during DDLT in recipients with high MELD scores and fatty grafts may be associated with poorer outcomes compared to desflurane.

Current Understanding of Marginal Grafts in Liver Transplantation

End-stage liver disease (ESLD), stemming from a spectrum of chronic liver pathologies including chronic liver failure, acute cirrhosis decompensation and hepatocellular carcinoma, imposes a significant global healthcare burden. Liver transplantation (LT) remains the only treatment for ESLD. However, the escalating mortality on transplant waitlists has prompted the utilization of marginal liver grafts in LT procedures. These grafts primarily encompass elderly livers, steatotic livers, livers from donation after circulatory death, split livers and those infected with the hepatitis virus. While the expansion of the donor pool offers promise, it also introduces concomitant risks. These encompass graft failure, biliary and cardiovascular complications, the recurrence of liver disease and reduced patient and graft survival. Consequently, various established strategies, ranging from improved donor-recipient matching to surgical interventions, have emerged to mitigate these risks. This article undertakes a comprehensive assessment of the current landscape, evaluating the viability of diverse marginal liver grafts. Additionally, it synthesizes approaches aimed at enhancing the quality of such marginal liver grafts. The overarching objective is to augment the donor pool and ameliorate the risk factors associated with the shortage of liver grafts.

Dynamic changes in the mouse hepatic lipidome following warm ischemia reperfusion injury

Liver failure secondary to metabolic dysfunction-associated steatotic liver disease (MASLD) has become the most common cause for liver transplantation in many parts of the world. Moreover, the prevalence of MASLD not only increases the demand for liver transplantation, but also limits the supply of suitable donor organs because steatosis predisposes grafts to ischemia-reperfusion injury (IRI). There are currently no pharmacological interventions to limit hepatic IRI because the mechanisms by which steatosis leads to increased injury are unclear. To identify potential novel mediators of IRI, we used liquid chromatography and mass spectrometry to assess temporal changes in the hepatic lipidome in steatotic and non-steatotic livers after warm IRI in mice. Our untargeted analyses revealed distinct differences between the steatotic and non-steatotic response to IRI and highlighted dynamic changes in lipid composition with marked changes in glycerophospholipids. These findings enhance our knowledge of the lipidomic changes that occur following IRI and provide a foundation for future mechanistic studies. A better understanding of the mechanisms underlying such changes will lead to novel therapeutic strategies to combat IRI.

Lifestyle Optimization Leads to Superior Liver Regeneration in Live Liver Donors and Decreases Early Allograft Dysfunction in Recipients: A Randomized Control Trial

INTRODUCTION

The aim of the current randomized control trial was to assess the efficacy of donor lifestyle optimization on liver regeneration and outcome following live donor liver transplantation.

METHODS

Live liver donors (LLDs) who were fit with no or minimal steatosis were randomized to receive either a customized low-calorie diet with calorie intake equalling their basal requirement along with exercise for 2 weeks before surgery versus to continue their normal routine lifestyle. Primary objectives were the difference in the day of normalization of serum bilirubin and PT-International normalized ratio and the percentage growth of the liver at postoperative day 7 and 14. Secondary objectives were differences in intraoperative liver biopsy, liver-regeneration markers, blood loss, hospital stay, the complication rate in LLDs, and rates of early graft dysfunction (EGD) in recipients.

RESULTS

Sixty-two consecutive LLDs were randomized (28 in intervention vs. 34 in control). Baseline parameters and graft parameters were similar in both groups. LLDs in the intervention arm had significantly decreased calorie intake ( P <0.005), abdominal girth ( P <0.005), BMI ( P =0.05), and weight ( P <0.0005). The mean blood loss ( P =0.038), day of normalization of bilirubin ( P =0.005) and International normalized ratio ( P =0.061), postoperative peak aspartate transaminase ( P =0.003), Alanine transaminase ( P =0.025), and steatosis ( P <0.005) were significantly less in the intervention group. There was significantly higher volume regeneration ( P =0.03) in donors in the intervention arm. The levels of TNF-α, IL-6, and IL-10 levels were significantly higher, while the TGF-β level was lower in donors in the intervention group. The rate of EGD was significantly higher in recipients in the control group ( P =0.043).

CONCLUSION

Lifestyle optimization of LLD is simple to comply with, improves liver regeneration in LLDs, and decreases EGD in recipients, thus can enhance donor safety and outcomes in live donor liver transplantation.

Impact of Donor Liver Macrovesicular Steatosis on Deceased Donor Yield and Posttransplant Outcome

BACKGROUND

The Scientific Registry of Transplant Recipients (SRTR) had not traditionally considered biopsy results in risk-adjustment models, yet biopsy results may influence outcomes and thus decisions regarding organ acceptance.

METHODS

Using SRTR data, which includes data on all donors, waitlisted candidates, and transplant recipients in the United States, we assessed (1) the impact of macrovesicular steatosis on deceased donor yield (defined as number of livers transplanted per donor) and 1-y posttransplant graft failure and (2) the effect of incorporating this variable into existing SRTR risk-adjustment models.

RESULTS

There were 21 559 donors with any recovered organ and 17 801 liver transplant recipients included for analysis. Increasing levels of macrovesicular steatosis on donor liver biopsy predicted lower organ yield: ≥31% macrovesicular steatosis on liver biopsy was associated with 87% to 95% lower odds of utilization, with 55% of these livers being discarded. The hazard ratio for graft failure with these livers was 1.53, compared with those with no pretransplant liver biopsy and 0% to 10% steatosis. There was minimal change on organ procurement organization-specific deceased donor yield or program-specific posttransplant outcome assessments when macrovesicular steatosis was added to the risk-adjustment models.

CONCLUSIONS

Donor livers with macrovesicular steatosis are disproportionately not transplanted relative to their risk for graft failure. To avoid undue risk aversion, SRTR now accounts for macrovesicular steatosis in the SRTR risk-adjustment models to help facilitate use of these higher-risk organs. Increased recognition of this variable may also encourage further efforts to standardize the reporting of liver biopsy results.

Expanding donor pool for live donor liver transplantation: utilization of donors with non-alcoholic steatohepatitis after optimization

INTRODUCTION

Potential live liver donors with non-alcoholic steatohepatitis (NASH) are rejected upfront for donation in live donor liver transplantation (LDLT). Herein, we share our experience of the feasibility of live liver donation in donors with NASH after successful donor optimization.

MATERIALS AND METHODS

Prospectively collected data of 410 consecutive donor hepatectomies from June 2011 to January 2018 were analyzed.

RESULTS

During the study period, NASH was diagnosed histopathologically in 17 donors. Four donors were rejected in view of grade 2 fibrosis on histology. Out of remaining 13 donors, six became eligible for donation following lifestyle changes, dietary modifications, and target weight reduction of ≥5%. Reversal of NASH was confirmed on repeat liver biopsy in all the 6 donors. Five out of 6 underwent right lobe (without MHV) donor hepatectomies, while one had left lobe donation. These donors had significantly higher peak bilirubin levels in the immediate post-operative period as compared to other non-NASH donors (4.00 ± 0.32 vs. 2.57 ± 1.77 mg/dL, p = 0.043). In addition, post-hepatectomy normalization of hyperbilirubinemia, if any, was slower in donors with NASH (7 ± 1.3 vs. 5 ± 1.7 days, p = 0.016). However, none of these donors had post-hepatectomy liver failure. All these donors were discharged after an average hospital stay of 8 ± 1.7 days. Their respective recipients had uneventful post-operative courses without complications. Both the recipients and donors are having satisfactory liver functions after 46.7 ± 10.2 months of follow-up.

CONCLUSION

Scrupulous selection of live liver donors with NASH can open a door for expanding the organ pool in LDLT after a successful donor optimization program.

Hepatic macrosteatosis in the US pediatric deceased liver donor population

INTRODUCTION

The pediatric obesity epidemic is associated with early development of hepatic macrosteatosis, a hallmark of non-alcoholic fatty LI disease, which is thought to be more rapidly progressive in children than adults. Macrosteatosis in adult allografts is associated with allograft loss, but this has not been examined in pediatric donors.

METHODS

We studied all pediatric potential whole LI donors (2005-2018) who had a LI biopsy in the SRTR (n = 862) and whose LI was transplanted (n = 862). Macrosteatosis was abstracted from biopsy reports and compared to values in the SRTR standard analytic file. Recipients of macrosteatotic pediatric allografts were matched 1:1 to recipients of non-macrosteatotic pediatric allografts by propensity score matching on donor/recipient variables. All-cause allograft loss was estimated via Kaplan-Meier analysis and Cox proportional hazards model.

RESULTS

From 2005 to 2018, the proportion of pediatric donors (age ≥2 years) with obesity increased (14.8% to 21.7%; p < .001), as did the proportion of pediatric deceased whole LI-only donor allografts with macrosteatosis (n = 10 648; 1.8% to 3.9%; p < .001). The median degree of macrosteatosis among macrosteatotic donors was 10% (IQR 5-30). There were no significant differences in all-cause allograft loss between recipients of pediatric LI allografts with and without macrosteatosis at 90 days (p = .11) or 1 year (p = .14) post-transplant in Kaplan-Meier analysis or a Cox proportional hazards model (p > .05).

CONCLUSION

Obese pediatric LI donors have increased over time and were more likely to have hepatic macrosteatosis; however, pediatric macrosteatosis did not appear to adversely affect recipient outcomes.

Impact of Donor and Recipient Clinical Characteristics and Hepatic Histology on Steatosis/Fibrosis Following Liver Transplantation

BACKGROUND

Deceased donor and recipient predictors of posttransplant steatosis/steatohepatitis and fibrosis are not well known. Our aim was to evaluate the prevalence and assess donor and recipient predictors of steatosis, steatohepatitis, and fibrosis in liver transplantation recipients.

METHODS

Using the immune tolerance network A-WISH multicenter study (NCT00135694), donor and recipient demographic and clinical features were collected. Liver biopsies were taken from the donor liver at transplant, and from recipients per protocol and for-cause (ie, abnormal transaminases and to rule out rejection) and were interpreted by a central pathologist.

RESULTS

One hundred eighty-three paired donor/recipients liver biopsies at the time of transplant and posttransplant follow-up (median time 582 d; average time to last biopsies was 704 d [SD ± 402 d]) were analyzed. Donor steatosis did not influence recipient steatosis or fibrosis. Ten of 183 recipients had steatohepatitis on the last biopsy. Recipient body mass index at the time of liver biopsy was the most influential factor associated with posttransplant steatosis. Both donor and recipient metabolic syndrome features were not associated with graft steatosis. Untreated hepatitis C viral (HCV) infection was the most influential factor associated with the development of allograft fibrosis.

CONCLUSIONS

In a large experience evaluating paired donor and recipient characteristics, recipient body mass index at the time of liver biopsy was most significantly associated with posttransplant steatosis. Untreated HCV etiology influenced graft fibrosis. Thus relative to untreated HCV, hepatic fibrosis in those with steatosis/steatohepatitis is less common though long-term follow-up is needed to determine the course of posttransplant fibrosis. Emphasis on recipient weight control is essential.

Single-cell profiling reveals distinct immune phenotypes that contribute to ischaemia-reperfusion injury after steatotic liver transplantation

OBJECTIVES

The discrepancy between supply and demand of organ has led to an increased utilization of steatotic liver for liver transplantation (LT). Hepatic steatosis, however, is a major risk factor for graft failure due to increased susceptibility to ischaemia-reperfusion (I/R) injury during transplantation.

MATERIALS AND METHODS

To assess the plasticity and phenotype of immune cells within the microenvironment of steatotic liver graft at single-cell level, single-cell RNA-sequencing (scRNA-Seq) was carried out on 23 675 cells from transplanted rat livers. Bioinformatic analyses and multiplex immunohistochemistry were performed to assess the functional properties, transcriptional regulation, phenotypic switching and cell-cell interactions of different cell subtypes.

RESULTS

We have identified 11 different cell types in transplanted livers and found that the highly complex ecosystem was shaped by myeloid-derived cell subsets that transit between different states and interact mutually. Notably, a pro-inflammatory phenotype of Kupffer cells (KCs) with high expression of colony-stimulating factor 3 (CSF3) that was enriched in transplanted steatotic livers was potentially participated in fatty graft injury. We have also detected a subset of dendritic cells (DCs) with highly expressing XCR1 that was correlated with CD8+ T cells, mediating the severer steatotic liver damage by I/R injury.

CONCLUSIONS

The findings of our study provide new insight into the mechanisms by which steatosis exacerbates liver damage from I/R injury. Interventions based on these observations create opportunities in attenuating fatty liver graft injury and expanding the donor pool.

Weight loss interventions in living donor liver transplantation as a tool in expanding the donor pool: A systematic review and meta-analysis

BACKGROUND

With increasing rates of liver transplantation and a stagnant donor pool, the annual wait list removals have remained high. Living donor liver transplantation (LDLT) is an established modality in expanding the donor pool and is the primary method of liver donation in large parts of the world. Marginal living donors, including those with hepatic steatosis, have been used to expand the donor pool. However, due to negative effects of steatosis on graft and recipient outcomes, current practice excludes overweight or obese donors with more than 10% macro vesicular steatosis. This has limited a potentially important source to help expand the donor pool. Weight loss is known to improve or resolve steatosis and rapid weight loss with short-term interventions have been used to convert marginal donors to low-risk donors in a small series of studies. There is, however, a lack of a consensus driven standardized approach to such interventions.

AIM

To assess the available data on using weight loss interventions in potential living liver donors with steatotic livers and investigated the feasibility, efficacy, and safety of using such donors on the donor, graft and recipient outcomes. The principal objective was to assess if using such treated donor livers, could help expand the donor pool.

METHODS

We performed a comprehensive literature review and meta-analysis on studies examining the role of short-term weight loss interventions in potential living liver donors with hepatic steatosis with the aim of increasing liver donation rates and improving donor, graft, and recipient outcomes.

RESULTS

A total of 6 studies with 102 potential donors were included. Most subjects were males (71). All studies showed a significant reduction in body mass index post-intervention with a mean difference of -2.08 (-3.06, 1.10, I 2 = 78%). A significant reduction or resolution of hepatic steatosis was seen in 93 of the 102 (91.2%). Comparison of pre- and post-intervention liver biopsies showed a significant reduction in steatosis with a mean difference of -21.22 (-27.02, -15.43, I 2 = 56%). The liver donation rates post-intervention was 88.5 (74.5, 95.3, I 2 = 42%). All donors who did not undergo LDLT had either recipient reasons or had fibrosis/steatohepatitis on post intervention biopsies. Post-operative biliary complications in the intervention group were not significantly different compared to controls with an odds ratio of 0.96 [(0.14, 6.69), I 2 = 0]. The overall post-operative donor, graft, and recipient outcomes in treated donors were not significantly different compared to donors with no steatosis.

CONCLUSION

Use of appropriate short term weight loss interventions in living liver donors is an effective tool in turning marginal donors to low-risk donors and therefore in expanding the donor pool. It is feasible and safe, with comparable donor, graft, and recipient outcomes, to non-obese donors. Larger future prospective studies are needed.

Moderately Macrosteatotic Livers Have Acceptable Long-Term Outcomes but Higher Risk of Immediate Mortality

BACKGROUND AND AIMS

Liver transplantation is the most effective treatment for end-stage liver disease (ESLD). Whether moderately macrosteatotic livers (30%-60%) represent a risk for worsened graft function is controversial. The uncertainty, in large part, is owing to the heterogeneous steatosis grading. Our aim was to determine the short- and long-term outcomes of moderately macrosteatotic allografts that were graded according to a standardized institutional protocol.

METHODS

We performed a retrospective analysis of transplants performed between 1994 and 2014. All patients with allografts biopsied pretransplantation were included. Relevant donor and recipient variable were recorded. Moderately macrosteatotic livers were compared with mildly macrosteatotic and nonsteatotic livers. Primary outcomes of interest were patient survival at 90 days, 1 year, and 5 years. Cox regression analyses were carried out to compare survival between the 2 groups.

RESULTS

We compared 65 allografts with moderate macrosteatosis and 810 with no or mild macrosteatosis. Patients with moderately macrosteatotic allografts were 2.69 times as likely to die within the first 90 days after transplant (75.1% vs 91.6% survival) after adjusting for donor age, donor race, recipient age, recipient race, recipient body mass index, recipient diabetes, presence of hepatocellular carcinoma, days on waitlist, Model for End-Stage Liver Disease (MELD) score at transplantation, cold ischemia time. However, for recipients who survive 90 days, moderately macrosteatotic allografts had comparable long-term survival.

CONCLUSION

Our study shows that moderate macrosteatosis is a strong predictor of early but not late mortality. Further studies are needed to distinguish the specific cohort of patients for whom moderately macrosteatotic allografts will lead to acceptable outcomes.

Evolution of the liver biopsy and its future

Liver biopsies are commonly used to evaluate a wide variety of medical disorders, including neoplasms and post-transplant complications. However, its use is being impacted by improved clinical diagnosis of disorders, and non-invasive methods for evaluating liver tissue and as a result the indications of a liver biopsy have undergone major changes in the last decade. The evolution of highly effective treatments for some of the common indications for liver biopsy in the last decade (e.g., viral hepatitis B and C) has led to a decline in the number of liver biopsies in recent years. At the same time, the emergence of better technologies for histologic evaluation, tissue content analysis and genomics are among the many new and exciting developments in the field that hold great promise for the future and are going to shape the indications for a liver biopsy in the future. Recent advances in slide scanners now allow creation of "digital/virtual" slides that have image of the entire tissue section present in a slide [whole slide imaging (WSI)]. WSI can now be done very rapidly and at very high resolution, allowing its use in routine clinical practice. In addition, a variety of technologies have been developed in recent years that use different light sources and/or microscopes allowing visualization of tissues in a completely different way. One such technique that is applicable to liver specimens combines multiphoton microscopy (MPM) with advanced clearing and fluorescent stains known as Clearing Histology with MultiPhoton Microscopy (CHiMP). Although it has not yet been extensively validated, the technique has the potential to decrease inefficiency, reduce artifacts, and increase data while being readily integrable into clinical workflows. Another technology that can provide rapid and in-depth characterization of thousands of molecules in a tissue sample, including liver tissues, is matrix assisted laser desorption/ionization (MALDI) mass spectrometry. MALDI has already been applied in a clinical research setting with promising diagnostic and prognostic capabilities, as well as being able to elucidate mechanisms of liver diseases that may be targeted for the development of new therapies. The logical next step in huge data sets obtained from such advanced analysis of liver tissues is the application of machine learning (ML) algorithms and application of artificial intelligence (AI), for automated generation of diagnoses and prognoses. This review discusses the evolving role of liver biopsies in clinical practice over the decades, and describes newer technologies that are likely to have a significant impact on how they will be used in the future.

Sequential Protocol Biopsies Post-Liver Transplant From Donors With Moderate Macrosteatosis: What Happens to the Fat?

The number of steatotic deceased donor livers encountered has continued to rise as a result of the obesity epidemic. Little is known about the histological characteristics of moderately macrosteatotic livers over time in the recipient following liver transplantation (LT). All recipients undergoing LT at Mayo Clinic Florida with donor livers with moderate macrosteatosis (30%-60%) from 2000-2017 were identified (n = 96). Routine protocol liver biopsies were performed 1-week and 6-months following LT. All liver donor and protocol biopsies were read by an experienced liver pathologist. Of the 96 moderate macrosteatosis LTs, 70 recipients had post-LT protocol liver biopsies available and comprised the study cohort. Median donor allograft macrosteatosis at the time of transplant was 33% (IQR, 30%-40%) compared with 0% (IQR, 0%-2%) at 1-week (P < 0.001) and 0% (IQR, 0%-0%) at 6-months (P < 0.001) following LT. Biopsies at 1-week post-LT displayed pericentral necrosis in 57.1% of recipients and lipopeliosis in 34.3% of recipients. In the 6-month post-LT biopsies, cholestasis was seen in 3 (4.3%) of the recipients, whereas grade 2 fibrosis was seen in 6 recipients (8.6%). Graft survival at 5 years in the present cohort was 74.0%. Moderate macrosteatosis (30%-60%) in the donor allograft demonstrates complete reversal on liver biopsies performed as early as 7 days following LT and remains absent at 6-months following LT. Both pericentral necrosis and lipopeliosis are common features on day 7 biopsies. Despite these encouraging findings, the perioperative risks of using these livers (postreperfusion cardiac arrest and primary nonfunction) should not be understated. Long-term graft survival is acceptable in patients who are able to overcome the immediate perioperative risk of using moderately steatotic donor livers.

Monoacylglycerol Acyltransferase 1 Knockdown Exacerbates Hepatic Ischemia/Reperfusion Injury in Mice With Hepatic Steatosis

Nonalcoholic fatty liver disease (NAFLD) is becoming the most common indication for liver transplantation. The growing prevalence of NAFLD not only increases the demand for liver transplantation, but it also limits the supply of available organs because steatosis predisposes grafts to ischemia/reperfusion injury (IRI) and many steatotic grafts are discarded. We have shown that monoacylglycerol acyltransferase (MGAT) 1, an enzyme that converts monoacylglycerol to diacylglycerol, is highly induced in animal models and patients with NAFLD and is an important mediator in NAFLD-related insulin resistance. Herein, we sought to determine whether Mogat1 (the gene encoding MGAT1) knockdown in mice with hepatic steatosis would reduce liver injury and improve liver regeneration following experimental IRI. Antisense oligonucleotides (ASO) were used to knockdown the expression of Mogat1 in a mouse model of NAFLD. Mice then underwent surgery to induce IRI. We found that Mogat1 knockdown reduced hepatic triacylglycerol accumulation, but it unexpectedly exacerbated liver injury and mortality following experimental ischemia/reperfusion surgery in mice on a high-fat diet. The increased liver injury was associated with robust effects on the hepatic transcriptome following IRI including enhanced expression of proinflammatory cytokines and chemokines and suppression of enzymes involved in intermediary metabolism. These transcriptional changes were accompanied by increased signs of oxidative stress and an impaired regenerative response. We have shown that Mogat1 knockdown in a mouse model of NAFLD exacerbates IRI and inflammation and prolongs injury resolution, suggesting that Mogat1 may be necessary for liver regeneration following IRI and that targeting this metabolic enzyme will not be an effective treatment to reduce steatosis-associated graft dysfunction or failure.

Predictive role of vitamin B12 in acute kidney injury in living donor liver transplantation: a propensity score matching analysis

OBJECTIVES

We examine the association between vitamin B₁₂ level and risk for acute kidney injury (AKI) in patients undergoing living donor liver transplantation (LDLT).

DESIGN

Retrospective observational cohort study.

SETTING

University hospital, from January 2009 to December 2018.

PARTICIPANTS

A total of 591 patients who underwent elective LDLT were analysed in this study. Those with a preoperative history of kidney dysfunction, vitamin B₁₂ supplementation due to alcoholism, low vitamin B₁₂ (<200 pg/mL) or missing laboratory data were excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES

The population was classified into AKI and non-AKI groups according to Kidney Disease Improving Global Outcomes (KDIGO) criteria, and associations between perioperative factors and AKI were analysed. After 1:1 propensity score (PS) matching, the association between high vitamin B₁₂ (>900 pg/mL) and postoperative AKI was evaluated.

RESULTS

Preoperative vitamin B₁₂ was higher in the AKI group. Potentially significant perioperative factors from univariate analyses were entered into multivariate analyses, including preoperative factors (vitamin B₁₂, diabetes), intraoperative factors (hourly urine output) and donor graft fatty change in LDLT patients. PS matching analyses with adjustment using PS revealed that high serum vitamin B₁₂ (>900 pg/mL) was associated with risk for AKI, and the risk was 2.8-fold higher in patients with high vitamin B₁₂ than in those with normal vitamin B₁₂. Higher vitamin B₁₂ was also related to a higher AKI stage. In addition, inflammatory factors (C reactive protein, white blood cells and albumin) were associated with vitamin B₁₂ level.

CONCLUSIONS

Our study may improve the accuracy of predicting postoperative AKI by introducing preoperative vitamin B₁₂ into risk assessments for patients undergoing LDLT.

Donor PNPLA3 and TM6SF2 Variant Alleles Confer Additive Risks for Graft Steatosis After Liver Transplantation

BACKGROUND

The rs58542926 polymorphism in transmembrane 6 superfamily member 2 (TM6SF2) is a genetic factor predisposing to nonalcoholic fatty liver disease. We aimed to explore the effect of recipient and donor TM6SF2 rs58542926 genotypes on liver graft fat content after liver transplantation.

METHODS

Steatosis was evaluated in liver biopsies from 268 adult recipients. The influence of recipient and donor TM6SF2 genotypes, patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 genotypes, and nongenetic factors on the steatosis grade assessed 6-30 months after transplantation was analyzed by ordinal logistic regression.

RESULTS

The presence of the TM6SF2 c.499A allele in the donor (P = 0.014), PNPLA3 c.444G allele in the donor (P < 0.001), posttransplant body mass index (P < 0.001), and serum triglycerides (P = 0.047) independently predicted increased liver fat content on multivariable analysis, whereas noncirrhotic liver disease, as an indication for liver transplantation, was associated with lower risk of steatosis (P = 0.003). The effects of the donor TM6SF2 A and PNPLA3 G alleles were additive, with an odds ratio of 4.90 (95% confidence interval, 2.01-13.00; P < 0.001), when both minor alleles were present compared with an odds ratio of 2.22 (95% confidence interval, 1.42-3.61; P = 0.002) when only one of these alleles was present.

CONCLUSIONS

The donor TM6SF2 c.499A allele is an independent risk factor of liver graft steatosis after liver transplantation that is additive to the effects of donor PNPLA3 c.444G allele.

Efficacy and Safety of Weight Reduction of the Donor in Hepatic Steatosis for Living Donor Liver Transplantation

Background

Use of steatotic livers is a known risk factor for increased primary nonfunction after liver transplantation. This study investigated the efficacy and clinical outcome of simple weight reduction of steatosis for donors undergoing living-donor liver transplantation (LDLT).

Material/Methods

We defined two groups: the reduction group, which included donors with >30% macrovesicular steatosis and body mass index (BMI) >25 kg/m², and the conventional group, which included donors with <30% macrovesicular steatosis. Donors in the reduction group were educated about the goal of voluntary weight reduction to lose 5% of body weight, not exceeding 1.6 kg/week, and attempted to maintain weight reduction for at least 8 weeks.

Results

Weight reduction significantly improved steatosis (40.71±14.56 vs. 7.867±2.67, p=0.000). Body weight and BMI were reduced in the weight reduction group (85.40±8.254 kg vs. 76.27±7.556 kg, p=0.052; and 28.89±2.303 kg/m²vs. 26.16±1.629 kg/m², p=0.025, respectively). The transplanted grafts of recipients and remnant livers of donors showed intact liver function, and there was no difference in liver function tests between the conventional and reduction groups. No significant difference in graft survival was observed.

Conclusions

Simple weight reduction improves steatosis and contributes to safer LDLT for both recipient and donor. Importantly, according to our results, even steatotic livers can be used for LDLT after patients follow a simple weight reduction protocol.

Early Allograft Dysfunction Following Liver Transplant: Impact of Obesity, Diabetes, and Red Blood Cell Transfusion

PURPOSE

We examined the role of obesity and intraoperative red blood cell (RBC) and platelet transfusion in early allograft dysfunction (EAD) following liver transplantation (LT).

METHODS

This is a retrospective analysis of 239 adult deceased-donor LT recipients over a 10-year period. EAD was defined by Olthoff's criteria. Data collection included donor (D) and recipient (R) age, body mass index (BMI) ≥ 35 kg/m², diabetes mellitus, allograft macrosteatosis, and intraoperative (RBC) and platelet administration. We employed logistic regression to evaluate associations of these factors with EAD. Results are presented as odds ratios (OR) and 95% confidence intervals (CI) with corresponding P values. A P ≤ .05 was considered statistically significant.

RESULTS

EAD occurred in 85 recipients (36%). Macrosteatosis data were available for 199 donors. In the multivariate analyses, BMI-D ≥ 35 kg/m² increased the odds of developing EAD by 156% in the entire cohort (OR 2.56, 95% CI 1.09-6.01) and by 187% in recipients with macrosteatosis data (n = 199, OR 2.87, 95% CI 1.15-7.15). Each unit of RBCs increased the odds for EAD by 8% (OR 1.08, 95% CI 1.02-1.14) and, for the subgroup of 238 recipients with macrosteatosis data, by 9% (OR 1.09, 95% CI 1.02-1.16).

CONCLUSION

We found a significant independent association of donor obesity and intraoperative RBC transfusion with EAD but no such association for platelet administration, MELD score, age, recipient obesity, and diabetes.

Dynamic Metabolomics Study of the Bile Acid Pathway During Perioperative Primary Hepatic Carcinoma Following Liver Transplantation

Background

There are many situations of abnormal metabolism influencing liver graft function. This study aims to provide data for the development of liver function recovery after liver transplantation by dynamically analyzing metabolites of bile acids pathway in serum.

Material/Methods

A comprehensive metabolomics profiling of serum of 9 liver transplantation patients before transplantation, on the 1^st, 3^rd, and 7^th days after liver transplantation, and healthy individuals were performed by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Multivariate data and dynamic analysis were used to search for biomarkers between the metabolomics profiles present in perioperative liver transplantation and normal controls.

Results

Thirty-three differential endogenous metabolites were screened by the threshold of variable importance in the projection (VIP) from an orthogonal partial least square discriminant analysis (OPLS-DA) greater than 1.0, q-value <0.05, and fold change (FC) ≤0.8 or ≥1.2 between the preoperative group and the normal controls in negative mode. The metabolite intensities of taurocholic acid, taurochenodeoxycholic acid, chenodeoxycholic acid glycine conjugate, and glycocholic acid pre-transplantation were significantly higher than those of normal controls. The average metabolite intensities of taurocholic acid and taurochenodesoxycholic acid on the first day after liver transplantation were lower than those observed pre-transplantation. The average metabolite intensities on day 3 after liver transplantation showed a sudden increase and then decreased after 7 postoperative days. The average metabolite intensities of glycocholic acid and chenodeoxycholic acid glycine conjugate showed an increasing trend on the 1^st, 3^rd, and 7^th days after liver transplantation.

Conclusions

Use of taurocholic acid and taurochenodeoxycholic acid-related bile secretion, liver regeneration, and de novo bile acid synthesis may help clinical evaluation and provide data for the development of liver function recovery after liver transplantation.

N-Acetylcysteine Reduced Ischemia and Reperfusion Damage Associated with Steatohepatitis in Mice

N-acetylcysteine (NAC) is a pharmacological alternative with great potential for reducing the deleterious effects of surgical procedures on patients with steatohepatitis. We evaluated the effect of NAC on hepatic ischemia/reperfusion (I/R) injury in C57BL/6J mice, 8 weeks-old, weighing 25-30 g, with steatohepatitis induced by a methionine- and choline-deficient (MCD) diet. Groups: MCD group (steatohepatitis), MCD-I/R group (steatohepatitis plus 30 min of 70% liver ischemia and 24 h of reperfusion), MCD-I/R+NAC group (same as MCD-I/R group plus 150 mg/kg NAC 15 min before ischemia), and control group (normal AIN-93M diet). Liver enzymes and histopathology; nitrite and TBARS (thiobarbituric acid reactive substances) levels; pro-inflammatory cytokines; antioxidants enzymes; Nrf2 (nuclear factor erythroid-2-related factor 2) expression; and apoptosis were evaluated. In the group treated with NAC, reductions in inflammatory infiltration; AST (aspartate aminotransferase), nitrite, and TBARS levels; GPx (gutathione peroxidase) activity; cytokines synthesis; and number of apoptotic cells were observed while the GR (glutathione reductase) activity was increased. No differences were observed in Nfr2 expression or in SOD (superoxide dismutase), CAT (catalase), and GST (glutathione S-transferase) activities. Thus, it may be concluded that NAC exerts beneficial effects on mice livers with steatohepatitis submitted to I/R by reducing oxidative stress, inflammatory response, and cell death.

Liver Steatosis in Brain-Dead Donors: Progression Pattern and Affecting Factors

OBJECTIVES

No study has investigated the short-term effect of acute insulin resistance on liver steatosis in critically ill condition. We analyzed the effects of critically ill conditions of brain-dead donors (BDDs) on the development and progression of liver steatosis to investigate the influencing factors.

METHODS

This study was conducted retrospectively between January 2003 and December 2017. BDDs were for organ procurement. BDDs with body mass indexes (BMIs) < 18.5 kg/m² and ≥ 30 kg/m² were excluded. Liver steatosis was defined as ≥5% of the fat vacuole. The serum glucose level (SGL) was used to reflect insulin resistance.

RESULTS

Of the 179 BDDs, 87 (48.6%) had liver steatosis. BMI (r = 0.176, P = .019) and SGL (r = 0.267, P < .001) were correlated with steatosis. The length of the predonation period (LPDP) was negatively correlated with steatosis (r = -0.379, P < .001). BMI (odds ratio 1.266, P = .002), SGL ≥180 mg/dL (odds ratio 2.825, P = .003), and LPDP (odds ratio 0.885, P = .001) were independent risk factors for liver steatosis.

CONCLUSION

Liver steatosis is related to the SGL and BMI. Liver steatosis develops acutely in the early phase of critical illness and patients recover gradually.

Non-alcoholic Fatty Liver Disease: Growing Burden, Adverse Outcomes and Associations

Nonalcoholic fatty liver disease (NAFLD) is a systemic disorder with a complex multifactorial pathogenesis and heterogenous clinical manifestations. NAFLD, once believed to be an innocuous condition, has now become the most common cause of chronic liver disease in many countries worldwide. NAFLD is already highly prevalent in the general population, and owing to a rising incidence of obesity and diabetes mellitus, the incidence of NAFLD and its impact on global healthcare are expected to increase in the future. A subset of patients with NAFLD develops progressive liver disease leading to cirrhosis, hepatocellular carcinoma, and liver failure. NAFLD has emerged as one of the leading causes of cirrhosis and hepatocellular carcinoma in recent years. Moreover, HCC can occur in NAFLD even in absence of cirrhosis. Compared with the general population, NAFLD increases the risk of liver-related, cardiovascular and all-cause mortality. NAFLD is bidirectionally associated with metabolic syndrome. NAFLD increases the risk and contributes to aggravation of the pathophysiology of atherosclerosis, cardiovascular diseases, diabetes mellitus, and chronic kidney disease. In addition, NAFLD is linked to colorectal polyps, polycystic ovarian syndrome, osteoporosis, obstructive sleep apnea, stroke, and various extrahepatic malignancies. Extended resection of steatotic liver is associated with increased risk of liver failure and mortality. There is an increasing trend of NAFLD-related cirrhosis requiring liver transplantation, and the recurrence of NAFLD in such patients is almost universal. This review discusses the growing burden of NAFLD, its outcomes, and adverse associations with various diseases.

Outcome of Living-Donor Liver Transplantation Using Grafts from Donors Treated for Fatty Liver

Background

The aim of this study was to determine the efficacy of treating donors’ fatty liver (FL) and to assess early graft function in recipients who received treated FL grafts in living-donor liver transplantation (LDLT).

Material/Methods

Data were collected for adult-to-adult LDLTs. Donors diagnosed with FL (FL group) received diet–exercise and pharmacological treatment. The perioperative findings and early transplanted graft function were compared with those of donors without FL (non-FL group) during the same period.

Results

Of 30 donors, 8 were determined to have FL. The median duration of treatment for FL was 58 days. The liver-to-spleen attenuation ratios on CT scan in the FL group were significantly improved after treatment: 0.95 (0.62–1.06) to 1.2 (1.12–1.46) (P=0.003). Liver biopsy prior to donor surgery showed ≤10% fatty infiltration. Postoperative laboratory findings of the donors in the FL group were comparable to those in the non-FL group: maximum alanine transaminase (189.6±94.7 IU/L vs. 196.8±57.4) and maximum total bilirubin (2.2±1.1 mg/dL vs. 1.7±0.5 mg/dL). No major complications were observed after donor hepatectomy in either group. There were no significant differences between the 2 groups in early graft function, as evaluated by laboratory data, ascites volume, and bile production 2 weeks postoperatively. Graft and patient survival were 100% in both groups at 3 months.

Conclusions

Preoperative intentional treatment for FL was effective. Early graft function and donor postoperative course were comparable in the 2 groups. These results suggest that well-treated steatotic grafts can be used without jeopardizing donor safety.

Rapid Decrease in Liver Graft Steatosis in the Early Post-transplant Period: A Blinded and Randomized Study

AIMS

Previous research suggests a rapid post-transplant decrease in liver steatosis. With increased use of liver grafts with steatosis, better understanding of this post-transplant change will facilitate successful liver transplantation. This study compares liver reperfusion biopsies with early post-transplant surveillance biopsies to evaluate and quantitate change in steatosis.

METHODS

All liver grafts with ≥ 10% steatosis were extracted for analysis. Allograft biopsies on day 0 and day 3 post-transplant were randomly read, in a blinded fashion, by a single, experienced liver pathologist. Ten non-steatotic grafts were interspersed as controls. Slides were scored for macro-, micro-, and total steatosis.

RESULTS

Overall, 151 subjects with steatosis were available for study. A decrease in steatosis was seen for most grafts: microvesicular (69%), macrovesicular (64%), and total steatosis (77%). There was a greater decrease in steatosis for grafts with high baseline steatosis (> 40% baseline steatosis with -30% reduction; 20%-39% baseline steatosis with -15% reduction; and < 20% baseline steatosis with -5% reduction).

CONCLUSIONS

These results confirm a marked post-transplant decrease in steatosis that occurs within 3 to 5 days for most liver grafts with steatosis. These findings support the continued use of liver grafts with steatosis as this pathology appears to resolve quickly after transplant.

Impact of Donor Obesity on Outcomes After Orthotopic Heart Transplantation

Background

The impact of donor obesity on the outcome of orthotopic heart transplantation has not been studied. The aim of this study was to investigate the impact of donor obesity on the outcomes of adult orthotopic heart transplantation recipients.

Methods and Results

Data were obtained from the United Network for Organ Sharing database. All adult (age ≥18 years) patients undergoing orthotopic heart transplantation from 2000 through 2016 were included (n=31 920). We stratified the cohort by donor body mass index (BMI); 13 015 patients (40.8%) received a heart from a normal‐weight donor (BMI 18.5–24.9), 11 271 patients (35.3%) received a heart from an overweight donor (BMI 25.0–29.9), 4910 patients (15.4%) received a heart from an obese donor (BMI 30.0–34.9), and 2724 patients (8.5%) received a heart from an extremely obese donor (BMI ≥35). The cohort of obese donors was older, included a higher incidence of diabetes mellitus, and had a higher creatinine. Our data also showed that the recipients of obese donor grafts were older, had a higher BMI, creatinine, percentage of diabetes mellitus, and longer total waiting period. There was no significant difference detected in the survival likelihood (P=0.08) of patients based on a donor's BMI‐based categorized cohort. There were no significant differences found in the overall survival probability among 4 groups in the adjusted survival analyses (P=0.25).

Conclusions

This study demonstrated that patients receiving higher BMI donor hearts might not be subjected to an increased risk of death, at least during the short term after transplant, compared with those using the normal‐weight donors.

Serum miR-33a is associated with steatosis and inflammation in patients with non-alcoholic fatty liver disease after liver transplantation

Background & aims

MiR-33a has emerged as a critical regulator of lipid homeostasis in the liver. Genetic deficiency of miR-33a aggravates liver steatosis in a preclinical model of non-alcoholic fatty liver disease (NAFLD), and relative expression of miR-33a is increased in the livers of patients with non-alcoholic steatohepatitis (NASH). It was unknown whether miR-33a is detectable in the serum of patients with NAFLD. We sought to determine whether circulating miR-33a is associated with histological hepatic steatosis, inflammation, ballooning or fibrosis, and whether it could be used as a serum marker in patients with NAFLD/NASH.

Methods

We analysed circulating miR-33a using quantitative PCR in 116 liver transplant recipients who underwent post-transplant protocol liver biopsy. Regression analysis was used to determine association of serum miR-33a with hepatic steatosis, inflammation, ballooning and fibrosis in liver biopsy.

Results

Liver graft steatosis and inflammation, but not ballooning or fibrosis, were significantly associated with serum miR-33a, dyslipidemia and insulin resistance markers on univariate analysis. Multivariate analysis showed that steatosis was independently associated with serum miR-33a, ALT, glycaemia and waist circumference, whereas inflammation was independently associated with miR-33a, HbA1 and serum triglyceride levels. Receiver operating characteristic analysis showed that exclusion of serum miR-33a from multivariate analysis resulted in non-significant reduction of prediction model accuracy of liver steatosis or inflammation.

Conclusions

Our data indicate that circulating miR-33a is an independent predictor of liver steatosis and inflammation in patients after liver transplantation. Although statistically significant, its contribution to the accuracy of prediction model employing readily available clinical and biochemical variables was limited in our cohort.

Omega-3 fatty acids are protective in hepatic ischemia reperfusion injury in the absence of GPR120 signaling

BACKGROUND

A single dose of IV fish oil (FO) before hepatic ischemia reperfusion injury (HIRI) increases hepatocyte proliferation and reduces necrosis in wild type (WT) mice. It has been suggested that the GPR120 receptor on Kupffer cells mediates FO's ability to reduce HIRI. The purpose of this study was to determine whether GPR120 is required for FO to reduce HIRI.

METHODS

Sixty-four (n = 8/group) adult male WT (C57BL/6) and GPR120 knockout (KO) mice received IV FO (1 g/kg) or saline 1 h prior to HIRI or sham operation. Mice were euthanized 24 h postoperatively for analysis of hepatic histology, NFκB activity, and serum alanine transaminase (ALT) levels.

RESULTS

FO pretreated livers had less necrosis after HIRI than saline pretreated livers in both WT (mean ± SEM 25.9 ± 7.3% less, P = 0.007) and KO (36.6 ± 7.3% less, P < 0.0001) mice. There was no significant difference in percent necrosis between WT-FO and KO-FO groups. Sham groups demonstrated minimal necrosis (0-1.9%). Mean [95% CI] ALT after HIRI was significantly higher (P = 0.04) in WT-Saline mice (1604 U/L [751-3427]) compared to WT-FO (321 U/L [150-686]) but was not significantly higher in KO-Saline mice compared to KO-FO. There were no differences in ALT between WT-FO and KO-FO mice who underwent HIRI or between groups who underwent sham surgery. There were no differences in NFκB or IKKβ activation among groups as measured by Western blot analysis.

CONCLUSIONS

IV FO pretreatment was able to reduce HIRI in GPR120 KO mice, suggesting the hepatoprotective effects of FO are not mediated by GPR120 alone.

Body Mass Index and Unenhanced CT as a Predictor of Hepatic Steatosis in Potential Liver Donors

BACKGROUND

In living-donor liver transplantation, donor hepatic steatosis is crucial for both the donor and the recipient. Body mass index (BMI) and the unenhanced computed tomography liver attenuation index (CT LAI) are noninvasive methods to predict hepatic steatosis in living-donor liver candidates.

AIM

To analyze the diagnostic accuracy of CT LAI in conjunction with different BMI values for macrovesicular steatosis in living-donor liver candidates.

METHODS

A total of 264 potential liver donors were included. The diagnostic accuracy of 2 CT LAI cut-offs and 3 BMI cut-off values for the assessment of hepatic steatosis ≥15% and ≤5% was determined.

RESULTS

Using CT LAI, the area under the receiver operating characteristic curve was 0.97 (95% CI = 0.89-0.99) for hepatic steatosis ≥15% in donors with BMI <25 kg/m². For detecting hepatic steatosis ≥15%, a CT LAI ≤0 had specificities of 100%, 76.2%, and 55.6% and positive predictive values of 100%, 95.5%, and 93.5% for patients with BMI values <25 kg/m², 25 to 29.9 kg/m², and ≥30 kg/m², respectively. According to logistic regression analyses, only CT LAI ≤0 was found to be independently associated with hepatic steatosis ≥15%.

CONCLUSIONS

In donors with BMI <30 kg/m² and a CT LAI value >6, liver biopsy might be avoided. Biopsy may be reserved solely for donors with CT LAI value >0 and BMI ≥30 kg/m² as the diagnostic accuracy of computed tomography for predicting hepatic steatosis decreases with increasing BMI.

The Impact of Steatosis on the Outcome of Liver Transplantation: A Meta-Analysis

Background and Aims

Liver transplantation is one of the most effective treatments for end-stage liver disease as well as for cases of acute liver failure. Facing organ donor shortage, liver transplant teams had to use marginal organs. Thus, increasing availability is a key concern of donor liver grafts including steatotic livers. However, the use of steatotic liver is still controversial. The aim of this systematic review and meta-analysis was to analyze the impact of steatosis on the outcome of liver transplantation.

Methods

We searched PubMed, Cochrane Library, Embase, Web of knowledge, and so on for studies published through May 31, 2018, in which patients experienced liver transplantation using fatty liver. All studies extracted outcome indicators, and we draw conclusions by contrasting outcome indicators in different groups of steatosis. Odds ratios and 95% confidence intervals were calculated. P<0.05 was considered as statistically significant difference.

Results

19 publications were included. There was no significant difference between the group of no steatosis and mild group in primary nonfunction rate (P=0.605) or early graft dysfunction rate (P=0.44). The PNF rate was significantly higher in moderate group (P=0.003) and severe group (P <0.001) compared with that in no steatosis group. The same results were seen in early graft dysfunction rate. However, graft survival rate and patient survival rate did not differ between groups.

Conclusions

Livers with mild steatosis, even with moderate or severe steatosis, could be suitable donor under strict control of transplant conditions.

Feasibility of non-enhanced CT for assessing longitudinal changes in hepatic steatosis

To evaluate the feasibility of computed tomography (CT) in the assessment of the change in hepatic steatosis (HS) in longitudinal follow-up by employing pathological HS as the reference standard.We retrospectively evaluated 38 living liver donor candidates (27 men and 11 women; mean age, 29.5 years) who underwent liver biopsy twice and had liver CT scans within 1 week of each biopsy. Four readers independently calculated CTL-S index by subtracting spleen attenuation from liver attenuation on non-enhanced CT images. The changes in pathological HS (ΔHS) and CTL-S (ΔCTL-S) between the 1st and 2nd examinations were assessed. The correlation between ΔHS and ΔCTL-S was assessed using the linear regression analysis. Inter-observer measurement error for ΔCTL-S among the 4 readers was assessed using the repeatability coefficient.ΔCTL-S showed a significant correlation with ΔHS in all readers (r = 0.571-0.65, P < .001). The inter-observer measurement error for ΔCTL-S was ±8.9. The ΔCTL-S values beyond the measurement error were associated with a consistent change in HS in 83.3% (13/15) to 100% (15/15), with sensitivities of 47.8 to 79.9% and specificities of 86.7 to 100% for detecting an absolute change of ≥10% in HS among the 4 readers. However, ΔCTL-S values within the measurement error were associated with a consistent change in HS in 43.5% (8/19) to 61.5% (16/26).The change in CTL-S roughly reflects the change in HS during longitudinal follow-up. A small change in CTL-S should not be considered meaningful, while a larger change in CTL-S beyond the measurement error strongly indicates a true change in HS.

Interleukin-33 / Cyclin D1 imbalance in severe liver steatosis predicts susceptibility to ischemia reperfusion injury

Transplanting donor livers with severe macrosteatosis is associated with increased risk of primary non-function (PNF). The purpose of this study was to identify steatosis-driven biomarkers as a predisposition to severe liver damage and delayed recovery following ischemia reperfusion injury. Wistar rats were fed a methionine- and choline-deficient (MCD) diet for up to three weeks to achieve severe macrosteatosis (>90%). Animals underwent diet withdrawal to control chow and/or underwent ischemia reperfusion and partial hepatectomy injury (I/R-PHx) and reperfused out to 7 days on control chow. For animals with severe macrosteatosis, hepatic levels of IL-33 decreased while Cyclin D1 levels increased in the absence of NF-κB p65 phosphorylation. Animals with high levels of nuclear Cyclin D1 prior to I/R-PHx either did not survive or had persistent macrosteatosis after 7 days on control chow. Survival 7 days after I/R-PHx fell to 57% which correlated with increased Cyclin D1 and decreased liver IL-33 levels. In the absence of I/R-PHx, withdrawing the MCD diet normalized IL-33, Cyclin D1 levels, and I/R-PHx survival back to baseline. In transplanted grafts with macrosteatosis, higher Cyclin D1 mRNA expression was observed. Shifts in Cyclin D1 and IL-33 expression may identify severely macrosteatotic livers with increased failure risk if subjected to I/R injury. Clinical validation of the panel in donor grafts with macrosteatosis revealed increased Cyclin D1 expression corresponding to delayed graft function. This pre-surgical biomarker panel may identify the subset of livers with increased susceptibility to PNF.

CXCR6 deficiency ameliorates ischemia-reperfusion injury by reducing the recruitment and cytokine production of hepatic NKT cells in a mouse model of non-alcoholic fatty liver disease

Fatty liver is used for transplantation due to organ shortage, but prone to cause complications like ischemia-reperfusion injury (IRI). NKT cells as a bridge between innate and adaptive immunity were reported to infiltrate the liver at the early phase of IRI induced in normal liver. However, the localization mechanism of NKT cells is not precise, and the role of NKT cells in fatty liver IRI is poorly understood. In present murine IRI model of non-alcoholic fatty liver disease, we demonstrated that although the number reduced in fatty liver, NKT cells still activated and accumulated to fatty liver following IRI, and contributed to IRI by producing inflammatory cytokine IFN-γ. We revealed that NKT cells in fatty liver expressed more CXCR6, a vital chemokine receptor; meanwhile, the ligand CXCL16 mRNA expression level in fatty liver was up-regulated. The up-regulation of the CXCR6/CXCL16 axis in fatty liver happened in IRI, which maybe endow NKT cells more chemotaxis. We further found CXCR6 deficiency reduced the recruitment of NKT cells in a tissue-dependent manner, and impaired the IFN-γ producing capacity of hepatic NKT cells. Serum ALT level and hepatic histology were both improved in CXCR6 deficient mice. The results provide evidence of the pathogenic role of NKT cells in fatty liver IRI, and important localization mechanism involving up-regulated CXCR6/CXCL16. Deficiency of CXCR6 protects the fatty liver from IRI by reducing the recruitment and cytokine production of hepatic NKT cells.

Overproduction of Tenascin-C Driven by Lipid Accumulation in the Liver Aggravates Hepatic Ischemia/Reperfusion Injury in Steatotic Mice

The purpose of this study was to assess the significance of tenascin-C (Tnc) expression in steatotic liver ischemia/reperfusion injury (IRI). The critical shortage in donor organs has led to the use of steatotic livers in transplantation regardless of their elevated susceptibility to hepatic IRI. Tnc is an endogenous danger signal extracellular matrix molecule involved in various aspects of immunity and tissue injury. In the current study, mice were fed with a steatosis-inducing diet and developed approximately 50% hepatic steatosis, predominantly macrovesicular, before being subjected to hepatic IRI. We report here that lipid accumulation in hepatocytes inflated the production of Tnc in steatotic livers and in isolated hepatic stellate cells. Moreover, we show that the inability of Tnc-/- deficient steatotic mice to express Tnc significantly protected these mice from liver IRI. Compared with fatty controls, Tnc-/- steatotic mice showed significantly reduced serum transaminase levels and enhanced liver histological preservation at both 6 and 24 hours after hepatic IRI. The lack of Tnc expression resulted in impaired lymphocyte antigen 6 complex, locus (Ly6G) neutrophil and macrophage antigen-1 (Mac-1) leukocyte recruitment as well as in decreased expression of proinflammatory mediators (interleukin 1β, tumor necrosis factor α, and chemokine [C-X-C motif] ligand 2) after liver reperfusion. Myeloperoxidase (MPO) is the most abundant cytotoxic enzyme secreted by neutrophils and a key mediator of neutrophil-induced oxidative tissue injuries. Using an in vitro model of steatosis, we also show that Tnc markedly potentiated the effect of steatotic hepatocytes on neutrophil-derived MPO activity. In conclusion, our data support the view that inhibition of Tnc is a promising therapeutic approach to lessen inflammation in steatotic livers and to maximize their successful use in organ transplantation.

The Macrophage Activation Marker Soluble CD163 is Associated With Early Allograft Dysfunction After Liver Transplantation

BACKGROUND/OBJECTIVES

Soluble CD163 (sCD163), a macrophage activation marker, is upregulated in conditions of macrophage proliferation and activation. Elevated sCD163 levels have been associated with liver disease severity and progression. During liver transplantation, the implanted liver is exposed to ischaemia and reperfusion injury, resulting in an acute inflammatory response and macrophage activation. The relationship between sCD163 levels during liver transplantation and the development of early allograft dysfunction (EAD) has not been investigated.

METHODS

We included 27 cirrhosis patients (age 55 [range 32-72] years, 23 men) on the waiting list for liver transplantation. Alcohol consumption and viral hepatitis were the most frequent causes for cirrhosis. Patients were characterised by standard biochemical analysis and based on clinical disease severity scores. Information about donor, graft and course of the liver transplantation was recorded. sCD163 levels were measured at the time of liver transplantation before surgery, 2 h after reperfusion, and then at 24 h after transplantation.

RESULTS

We observed above-normal sCD163 levels at baseline (5.9 mg/L [4.7-8.8]). Two hours after reperfusion, sCD163 levels increased significantly from baseline (8.4 mg/L [7.4-10.9]; P < 0.01). Twenty-four hours after transplantation, sCD163 levels were significantly reduced compared with baseline (3.7 mg/L [2.9-5.5]; P < 0.01). However, in patients with EAD (n = 16), sCD163 levels were increased compared with patients without EAD (4.1 [3.2-7.4] vs. 3.1 [2.8-3.8] mg/L; P = 0.03).

CONCLUSIONS

We observed elevated sCD163 levels in patients with EAD after liver transplantation, confirming macrophage activation to play a role in EAD. Thus, sCD163 may be used as an early marker for EAD after liver transplantation, but larger studies are warranted to validate these findings.

CT indices for the diagnosis of hepatic steatosis using non-enhanced CT images: development and validation of diagnostic cut-off values in a large cohort with pathological reference standard

OBJECTIVES

To compare the performances of CT indices for diagnosing hepatic steatosis (HS) and to determine and validate the CT index cut-off values.

METHODS

Three indices were measured on non-enhanced CT images of 4413 living liver donor candidates (2939 men, 1474 women; mean age, 31.4 years): hepatic attenuation (CT_L), hepatic attenuation minus splenic attenuation (CT_L-S), and hepatic attenuation divided by splenic attenuation (CT_L/S). The performances of these CT indices in diagnosing HS, relative to pathologic diagnosis, were compared in the development cohort of 3312 subjects by receiver operating characteristic (ROC) analysis. The cut-off values for diagnosing HS > 33% in the development cohort were determined at 95% specificity and 95% sensitivity using bootstrap ROC analysis, and the diagnostic performance of these cut-off values was validated in the test cohort of 1101 subjects.

RESULTS

CT_L-S showed the highest performance for diagnosing HS ≥ 5% and HS > 33% (areas under the curve (AUCs) = 0.737 and 0.926, respectively), followed by CT_L/S (AUCs = 0.732 and 0.925, respectively) and CT_L (AUCs = 0.707 and 0.880, respectively). For CT scans using 120 kVp, the CT_L-S cut-off values for highly specific (i.e., - 2.1) and highly sensitive (i.e., 7.6) diagnosis of HS > 33% resulted in a specificity of 96.4% with a sensitivity of 64.0% and a sensitivity of 97.3% with a specificity of 54.9%, respectively, in the test cohort.

CONCLUSION

CT indices using liver and spleen attenuations have higher performance for diagnosing HS than indices using liver attenuation alone. The CT_L-S cut-off values in this study may have utility for diagnosing HS in clinical practice and research.

KEY POINTS

• CT indices based on both liver attenuation and spleen attenuation (CT_L-Sand CT_L/S) have higher diagnostic performance than CT_Lbased on liver attenuation alone in diagnosing HS using various CT techniques. • The CT index cut-off values determined in this study can be utilized for reliable diagnosis or to rule out subjects with moderate to severe HS in clinical practice and research, including the selection of living liver donors and the development of cohorts with HS or healthy controls.

Oil Red O Is a Useful Tool to Assess Donor Liver Steatosis on Frozen Sections During Transplantation

Oil Red O is a useful tool to assess donor liver steatosis on frozen sections during transplantation. Steatosis is a frequent finding in liver evaluation during transplantation, accounting for 9% to 26% of biopsied donor liver. The degree of macrovesicular steatosis is classified as mild, moderate, and severe; the latter is considered an absolute contraindication to liver transplantation because it is associated with poor allograft outcome. Because of the scarcity of organs, there is a debate whether livers with less severe macrovesicular steatosis are still suitable for transplant. Consequently, tools or methods that allow a more accurate intraoperative assessment of steatosis on frozen sections are mandatory. The aim of this study is to improve intraoperative evaluation of steatosis during transplantation using Oil Red O stain on liver biopsies.

METHODS

Twenty consecutive liver biopsies of donors were collected during transplantation procedures from September 2017 to February 2018 at the Institute of Pathology of the University and Hospital Trust of Verona, Italy. Each liver biopsy was cut at a different thickness (3, 5, and 8 μm) and stained with both Oil Red O and conventional hematoxylin and eosin for intraoperative consultation. The degree (percentage of hepatocytes involved) of fatty changes was recorded. The results obtained during the intraoperative consultation were finally compared with the formalin-fixed and paraffin-embedded permanent section.

RESULTS

Assessment of steatosis on hematoxylin and eosin frozen sections was reported as mild in 17 cases (85%), moderate in 2 cases (10%) and severe in 1 case (5%). Oil Red O frozen sections reported the following results: mild steatosis in 16 cases (80%), moderate in 2 cases (10%), and severe in 2 cases (10%). The percentage of liver steatosis obtained with Oil Red O was consistent in all cases with that of the permanent sections. The staining procedure for Oil Red O required approximately 18 minutes.

CONCLUSIONS

Oil Red O special stain is a fast and inexpensive tool to improve the assessment of steatosis on frozen biopsies during liver transplantation.

Recombinant Human Soluble Thrombomodulin Attenuates Hepatic Ischemia and/or Reperfusion Injury by Inhibiting Leukocyte Accumulation in Mice With Normal and Fatty Liver

In an attempt to increase the number of donor livers, there has been an increased use of marginal donor livers, such as steatotic (fatty) livers that increase susceptibility to ischemia and reperfusion injury (IRI). Inflammatory cell accumulation has a greater role in IRI in steatotic liver than in normal liver. Although the recombinant human soluble thrombomodulin (rhsTM) attracts attention as a new treatment for disseminated intravascular coagulation, the therapeutic efficacy of rhsTM in hepatic IRI remains uncertain, especially in fatty livers. We aimed to demonstrate the effect of rhsTM on hepatic IRI using well-established in vivo experimental models with steatotic liver.

METHODS

C57/BL6 mice were divided into 2 groups: normal liver (NL) group and fatty liver (FL) group, in which the steatotic liver was induced by high-fat diet for 9 weeks. The mice in the NL and FL groups were premedicated with venous injection of rhsTM (TM) or saline (Control) as control groups. All 4 groups (NL-Control vs NL-TM, FL-Control vs FL-TM) were subjected to partial hepatic warm ischemia followed by reperfusion.

RESULTS

rhsTM significantly attenuated liver injury in the FL group as well as the NL group, as evidenced by transaminase levels and histologic finding after hepatic IRI. rhsTM remarkably decreased the accumulation of inflammatory cells, such as macrophages and neutrophils, in both NL and FL tissue after IRI. Furthermore, rhsTM depressed mRNA and protein expressions of adhesion molecules such as intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 in both NL and FL groups after IRI.

CONCLUSION

Our results demonstrate that rhsTM has a protective effect on fatty liver as well as normal liver after hepatic IRI. They also suggest that rhsTM contributes to attenuation of leukocyte accumulation caused by depressing expressions of adhesion molecules that facilitate accumulation of leukocytes in liver tissue in hepatic IRI.

The impact of diet-induced hepatic steatosis in a murine model of hepatic ischemia/reperfusion injury

The prevalence of obesity-associated nonalcoholic fatty liver disease has significantly increased over the past decade, and end-stage liver disease secondary to nonalcoholic steatohepatitis has become 1 of the most common indications for liver transplantation. This both increases the demand for organs and decreases the availability of donor livers deemed suitable for transplantation. Although in the past many steatotic livers were discarded due to concerns over enhanced susceptibility to ischemia/reperfusion injury (IRI) and organ failure, the discrepancy between supply and demand has resulted in increasing use of expanded criteria donor organs including steatotic livers. However, it remains controversial whether steatotic livers can be safely used for transplantation and how best to improve the performance of steatotic grafts. We aimed to evaluate the impact of diet-induced hepatic steatosis in a murine model of IRI. Using a diet of high trans-fat, fructose, and cholesterol (HTF-C) and a diet high in saturated fats, sucrose, and cholesterol (Western diet), we were able to establish models of mixed macrovesicular and microvesicular steatosis (HTF-C) and microvesicular steatosis (Western). We found that the presence of hepatic steatosis, whether it is predominantly macrovesicular or microvesicular, significantly worsens IRI as measured by plasma alanine aminotransferase levels and inflammatory cytokine concentration, and histological evaluation for necrosis. Additionally, we report on a novel finding in which hepatic IRI in the setting of steatosis results in the induction of the necroptosis factors, receptor interacting protein kinase (RIPK) 3, RIPK1, and mixed-lineage kinase domain-like. These data lay the groundwork for additional experimentation to test potential therapeutic approaches to limit IRI in steatotic livers by using a genetically tractable system. Liver Transplantation 24 908-921 2018 AASLD.

Grading fatty liver by ultrasound time-domain radiofrequency signal analysis: an in vivo study of rats

This study aimed to assess the severity of fatty liver (FL) by analyzing ultrasound radiofrequency (RF) signals in rats. One hundred and twenty rats (72 in the FL group and 48 in the control group) were used for this purpose. Histological results were the golden standard: 42 cases had normal livers (N), 30 cases had mild FL (L1), 25 cases had moderate FL (L2), 13 cases presented with severe FL (L3), and 10 cases were excluded from the study. Four RF parameters (Mean, Mean/SD ratio [MSR], skewness [SK], and kurtosis [KU] were extracted. Univariate analysis, spearman correlation analysis, and stepwise regression analysis were used to select the most powerful predictors. Receiver operating characteristic (ROC) analysis was used to compare the diagnostic efficacy of single indexes with a combined index (Y) expressed by a regression equation. Mean, MSR, SK, and KU were significantly correlated with FL grades (r=0.71, P<0.001; r=0.81, P<0.001; r=-0.79, P<0.001; and r=-0.74, P<0.001). The regression equation was Y=-4.48 + 3.20 × 10-2X1 + 3.15X2 (P<0.001), where Y=hepatic steatosis grade, X1 =Mean, and X2 =MSR. ROC analysis showed that the curve areas of the combined index (Y) were superior to simple indexes (Mean, MSR, SK, and KU) in evaluating hepatic steatosis grade, and they were 0.95 (L≥L1), 0.98 (L≥L2), and 0.99 (L≥L3). Ultrasound radiofrequency signal quantitative technology was a new, noninvasive, and promising sonography-based approach for the assessment of FL.

Liver cell therapy: is this the end of the beginning?

The prevalence of liver diseases is increasing globally. Orthotopic liver transplantation is widely used to treat liver disease upon organ failure. The complexity of this procedure and finite numbers of healthy organ donors have prompted research into alternative therapeutic options to treat liver disease. This includes the transplantation of liver cells to promote regeneration. While successful, the routine supply of good quality human liver cells is limited. Therefore, renewable and scalable sources of these cells are sought. Liver progenitor and pluripotent stem cells offer potential cell sources that could be used clinically. This review discusses recent approaches in liver cell transplantation and requirements to improve the process, with the ultimate goal being efficient organ regeneration. We also discuss the potential off-target effects of cell-based therapies, and the advantages and drawbacks of current pre-clinical animal models used to study organ senescence, repopulation and regeneration.

Pretreatment with intravenous fish oil reduces hepatic ischemia reperfusion injury in a murine model

BACKGROUND

Ischemia reperfusion injury is a barrier to liver surgery and transplantation, particularly for steatotic livers. The purpose of this study was to determine if pretreatment with a single dose of intravenous fish oil decreases hepatic ischemia reperfusion injury and improves recovery of injured livers.

METHODS

Sixty adult male C57BL/6 mice received 1 g/kg intravenous fish oil (Omegaven, Fresenius Kabi) or isovolumetric 0.9% NaCl (saline) via tail vein 1 hour before 30 minutes of 70% hepatic ischemia. Animals were killed 4, 8, or 24 hours postreperfusion, and livers were harvested for histologic analysis.

RESULTS

Four hours postreperfusion, saline-treated livers demonstrated marked ischemia diffusely around the central veins, while intravenous fish oil-treated livers demonstrated only patchy necrosis with intervening normal parenchyma. Eight hours postreperfusion, all livers demonstrated pale areas of cell loss with surrounding regenerating hepatocytes. Ki67 staining confirmed 14.4/10 high-powered field (95% confidence interval, 3.2-25.6) more regenerating hepatocytes around areas of necrosis in intravenous fish oil-treated livers. Twenty-four hours postreperfusion, all livers demonstrated patchy areas of necrosis, with an 89% (95% confidence interval, 85-92) decrease in the area of necrosis in intravenous fish oil-treated livers.

CONCLUSION

Intravenous fish oil treatment prior to hepatic ischemia reperfusion injury decreased the area of hepatic necrosis and increased hepatocyte regeneration compared to saline treatment in a mouse model.

Grade of donor liver microvesicular steatosis does not affect the postoperative outcome after liver transplantation

BACKGROUND

The potential effect of graft steatosis on the postoperative liver function is discussed controversially. The present study aimed to evaluate the effect of the donor liver microvesicular steatosis on the postoperative outcome after liver transplantation.

METHODS

Ninety-four patients undergoing liver transplantation at the University Hospital Aachen were included in this study. The patient cohort was divided into three groups according to the grade of microvesicular steatosis (MiS): MiS <30% (n=27), MiS 30%-60% (n=41) and MiS >60% (n=26). The outcomes after liver transplantation were evaluated, including the 30-day and 1-year patient and graft survival rates and the incidences of early allograft dysfunction (EAD) and primary nonfunction (PNF).

RESULTS

The incidences of EAD and PNF did not differ significantly between the groups. We observed 5 cases of PNF, one occurred in the MiS <30% group and 4 in the MiS 30%-60% group. The 30-day and 1-year graft survivals did not differ significantly between groups. The 30-day patient survival rates were 100% in all groups. The 1-year patient survival rates were 94.4% in the MiS <30% group, 87.9% in the MiS 30%-60% group and 90.9% in the MiS >60% group.

CONCLUSION

Microvesicular steatosis of donor livers has no negative effect on the postoperative outcome after liver transplantation.

Nutritional Therapy in Liver Transplantation

Protein-energy malnourishment is commonly encountered in patients with end-stage liver disease who undergo liver transplantation. Malnutrition may further increase morbidity, mortality and costs in the post-transplantation setting. The importance of carefully assessing the nutritional status during the work-up of patients who are candidates for liver replacement is widely recognized. The metabolic abnormalities induced by liver failure render the conventional assessment of nutritional status to be challenging. Preoperative loss of skeletal muscle mass, namely, sarcopenia, has a significant detrimental impact on post-transplant outcomes. It is essential to provide sufficient nutritional support during all phases of liver transplantation. Oral nutrition is preferred, but tube enteral nutrition may be required to provide the needed energy intake. Herein, the latest currently employed perioperative nutritional interventions in liver transplant recipients are thoroughly illustrated including synbiotics, micronutrients, branched-chain amino acid supplementation, immunonutrition formulas, fluid and electrolyte balance, the offering of nocturnal meals, dietary counselling, exercise and rehabilitation.