Nonalcoholic Steatohepatits and Liver Steatosis Modify Partial Hepatectomy Recovery

Effects of chronic liver disease on the outcomes of simultaneous resection of colorectal cancer with synchronous liver metastases: a propensity score matching study

Introduction

Given the rising prevalence of chronic liver disease (CLD), it is increasingly important to understand its impact on surgical outcomes. Our aim was to evaluate the impact of CLD on short-term outcomes in patients with colorectal cancer and synchronous liver metastases undergoing simultaneous surgery.

Methods

We retrospectively reviewed patients with colorectal cancer and liver metastases who underwent simultaneous resection between January 2013 and June 2022. Patients were divided into the CLD and non-CLD groups. Data regarding short-term surgical outcomes were compared between the two groups.

Results

A total of 187 patients were included. After propensity score matching, there were 42 patients in each group, and the basic characteristics of the two groups were similar. Patients with CLD had a significantly greater incidence of postoperative complications (47.6% vs. 26.2%; P = 0.042). The operation times of the CLD and non-CLD groups were similar (297 vs. 307.5 min, P = 0.537), and the blood loss was comparable between the two groups (250 vs. 155 ml, P = 0.066). No significant differences were observed between the two groups in pneumonia (P > 0.999), urinary infection rate (P > 0.999), ileus rate (P = 0.474), wound infection rates (P > 0.999), abdominal infection rate (P = 0.533), anastomotic leakage rate (P > 0.999), digestive hemorrhage rate (P > 0.999), bile leakage rate (P > 0.999), hepatic hemorrhage rate (P > 0.999), reoperation rate (P > 0.999), intensive care rate (P > 0.999), or severe liver failure (P > 0.999). There were no deaths in the two groups. CLD significantly prolonged the length of hospital stay (P = 0.011).

Discussion

CLD is an important factor affecting postoperative complications in patients with colorectal cancer liver metastases undergoing simultaneous surgery. Considering the large number of patients with CLD in China, more attention and medical care should be provided to patients with CLD who require simultaneous resection of colorectal cancer with synchronous liver metastases.

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.

The Role of Physical Activity in Nonalcoholic and Metabolic Dysfunction Associated Fatty Liver Disease

Sedentary behavior constitutes a pandemic health threat contributing to the pathophysiology of obesity and type 2 diabetes (T2D). Sedentarism is further associated with liver disease and particularly with nonalcoholic/metabolic dysfunction associated fatty liver disease (NAFLD/MAFLD). Insulin resistance (IR) represents an early pathophysiologic key element of NAFLD/MAFLD, prediabetes and T2D. Current treatment guidelines recommend regular physical activity. There is evidence, that physical exercise has impact on a variety of molecular pathways, such as AMP-activated protein kinase and insulin signaling as well as glucose transporter 4 translocation, modulating insulin action, cellular substrate flow and in particular ectopic lipid and glycogen storage in a positive manner. Therefore, physical exercise can lead to substantial clinical benefit in persons with diabetes and/or NAFLD/MAFLD. However, experience from long term observational studies shows that the patients’ motivation to exercise regularly appears to be a major limitation. Strategies to integrate everyday physical activity (i.e., nonexercise activity thermogenesis) in lifestyle treatment schedules might be a promising approach. This review aggregates evidence on the impact of regular physical activity on selected molecular mechanisms as well as clinical outcomes of patients suffering from IR and NAFLD/MAFLD.

A proof of concept study on real-time LiMAx CYP1A2 liver function assessment of donor grafts during normothermic machine perfusion

No single reliable parameter exists to assess liver graft function of extended criteria donors during ex-vivo normothermic machine perfusion (NMP). The liver maximum capacity (LiMAx) test is a clinically validated cytochromal breath test, measuring liver function based on 13CO2 production. As an innovative concept, we aimed to integrate the LiMAx breath test with NMP to assess organ function. Eleven human livers were perfused using NMP. After one hour of stabilization, LiMAx testing was performed. Injury markers (ALT, AST, miR-122, FMN, and Suzuki-score) and lactate clearance were measured and related to LiMAx values. LiMAx values ranged between 111 and 1838 µg/kg/h, and performing consecutive LiMAx tests during longer NMP was feasible. No correlation was found between LiMAx value and miR-122 and FMN levels in the perfusate. However, a significant inverse correlation was found between LiMAx value and histological injury (Suzuki-score, R = − 0.874, P < 0.001), AST (R = − 0.812, P = 0.004) and ALT (R = − 0.687, P = 0.028). Furthermore, a significant correlation was found with lactate clearance (R = 0.683, P = 0.043). We demonstrate, as proof of principle, that liver function during NMP can be quantified using the LiMAx test, illustrating a positive correlation with traditional injury markers. This new breath-test application separates livers with adequate cytochromal liver function from inadequate ones and may support decision-making in the safe utilization of extended criteria donor grafts.

Birkenfeld A, Sponholz C, A. Müller U, von Loeffelholz C. Blood Sugar Targets in Surgical Intensive Care—Management and Special Considerations in Patients With Diabetes

BACKGROUND

30-80% of patients being treated in intensive care units in the perioperative period develop hyperglycemia. This stress hyperglycemia is induced and maintained by inflammatory-endocrine and iatrogenic stimuli and generally requires treatment. There is uncertainty regarding the optimal blood glucose targets for patients with diabetes mellitus.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed and Google Scholar.

RESULTS

Patients in intensive care with pre-existing diabetes do not benefit from blood sugar reduction to the same extent as metabolically healthy individuals, but they, too, are exposed to a clinically relevant risk of hypoglycemia. A therapeutic range from 4.4 to 6.1 mmol/L (79-110 mg/dL) cannot be justified for patients with diabetes mellitus. The primary therapeutic strategy in the perioperative setting should be to strictly avoid hypoglycemia. Neurotoxic effects and the promotion of wound-healing disturbances are among the adverse consequences of hyperglycemia. Meta-analyses have shown that an upper blood sugar limit of 10 mmol/L (180 mg/dL) is associated with better outcomes for diabetic patients than an upper limit of less than this value. The target range of 7.8-10 mmol/L (140-180 mg/dL) proposed by specialty societies for hospitalized patients with diabetes seems to be the best compromise at present for optimizing clinical outcomes while avoiding hypoglycemia. The method of choice for achieving this goal in intensive care medicine is the continuous intravenous administration of insulin, requirng standardized, high-quality monitoring conditions.

CONCLUSION

Optimal blood sugar control for diabetic patients in intensive care meets the dual objectives of avoiding hypoglycemia while keeping the blood glucose concentration under 10 mmol/L (180 mg/dL). Nutrition therapy in accordance with the relevant guidelines is an indispensable pre - requisite.

A Narrative Review on the Role of AMPK on De Novo Lipogenesis in Non-Alcoholic Fatty Liver Disease: Evidence from Human Studies

5′AMP-activated protein kinase (AMPK) is known as metabolic sensor in mammalian cells that becomes activated by an increasing adenosine monophosphate (AMP)/adenosine triphosphate (ATP) ratio. The heterotrimeric AMPK protein comprises three subunits, each of which has multiple phosphorylation sites, playing an important role in the regulation of essential molecular pathways. By phosphorylation of downstream proteins and modulation of gene transcription AMPK functions as a master switch of energy homeostasis in tissues with high metabolic turnover, such as the liver, skeletal muscle, and adipose tissue. Regulation of AMPK under conditions of chronic caloric oversupply emerged as substantial research target to get deeper insight into the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Evidence supporting the role of AMPK in NAFLD is mainly derived from preclinical cell culture and animal studies. Dysbalanced de novo lipogenesis has been identified as one of the key processes in NAFLD pathogenesis. Thus, the scope of this review is to provide an integrative overview of evidence, in particular from clinical studies and human samples, on the role of AMPK in the regulation of primarily de novo lipogenesis in human NAFLD.

Cancer and hepatic steatosis

Non-alcoholic fatty liver disease (NAFLD) is a highly prevalent and increasing liver disease, which encompasses a variety of liver diseases of different severity. NAFLD can lead to liver cirrhosis with all its complications as well as hepatocellular carcinoma (HCC). Steatosis of the liver is not only related to obesity and other metabolic risk factors, but can also be caused by several drugs, including certain cytotoxic chemotherapeutic agents. In patients undergoing liver surgery, hepatic steatosis is associated with an increased risk of post-operative morbidity and mortality. This review paper summarizes implications of hepatic steatosis on the management of patients with cancer. Specifically, we discuss the epidemiological trends, pathophysiological mechanisms, and management of NAFLD, and its role as a leading cause of liver cancer. We elaborate on factors promoting immunosuppression in patients with NAFLD-related HCC and how this may affect the efficacy of immunotherapy. We also summarize the mechanisms and clinical course of chemotherapy-induced acute steatohepatitis (CASH) and its implications on cancer treatment, especially in patients undergoing liver resection.

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Non-alcoholic fatty liver disease can lead to cirrhosis with all its complications, including hepatocellular carcinoma.

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Chemotherapy-associated acute steatohepatitis is a side-effect of chemotherapeutic agents and may limit treatment options.

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In this review we summarize current clinical concepts of NAFLD and CASH that help clinicians in their clinical practice.

Risk of chemotherapy-associated liver injury (CALI) in PNPLA3 p.148M allele carriers: Preliminary results of a transient elastography-based study

BACKGROUND AND AIMS

Liver steatosis is one of the side effects of chemotherapy. The PNPLA3 p.I148M, TM6SF2 p.E167K and MBOAT7 p.G17E variants represent genetic determinants for progressive liver diseases. Here, we investigate their association with chemotherapy-associated steatosis.

PATIENTS AND METHODS

Prospectively, we recruited 87 patients undergoing systemic chemotherapy for gastrointestinal cancers. Hepatic fat (controlled attenuation parameter, CAP) and liver stiffness (LSM) were measured non-invasively before the initiation of chemotherapy (T0) and after at least two (T1) and four cycles (T2). Genetic variants were genotyped using allelic discrimination assays.

RESULTS

In the final dataset (n = 60) patients demonstrated the following CAP values: T0 - 215.0 ± 55.7 dB/m, T1 - 223.3 ± 53.6 dB/m, T2 - 223.4 ± 56.7 dB/m, consistent with mild steatosis. Initial CAP correlated with BMI (P < 0.01) and serum triglyceride concentrations (P = 0.03). Whereas at T0 none of the variants was associated with CAP or LSM, carriers of the prosteatotic PNPLA3 p.148M allele showed significantly (P = 0.008) higher steatosis at T1 as compared to patients carrying the homozygous wild-type genotype [II].

CONCLUSIONS

Our preliminary results show that patients carrying the PNPLA3 p.I148 M risk allele might be prone to hepatic fat accumulation during chemotherapy. Further studies are be needed to validate the clinical value of these findings.

Metabolic impact of partial hepatectomy in the non-alcoholic steatohepatitis animal model of methionine-choline deficient diet

In the liver, obesity is often manifested by the clinical disorder of the Non-Alcoholic Fatty Liver Disease (NAFLD). A proportion of NAFLD patients develop hepatic inflammation, known as Non-Alcoholic Steatohepatitis (NASH), which can end up in cirrhosis, or Hepatocellular Carcinoma (HCC). In this scenario, partial hepatectomy (PH) is an alternative to promote liver regeneration. However, as liver regeneration is impaired in NASH patients, more knowledge about its metabolic condition is needed to improve the regenerative response of the liver in this pathological condition. Although extensively employed, the panoply of molecular alterations involved in the regenerative response of the liver after partial hepatectomy PH is far from being fully characterized. Metabolic fingerprinting (metabolomics) is a powerful tool to help in the elucidation of complex metabolic networks, by means of a blind, naïve approach to study which metabolic nodes (metabolites) show the biggest variations between conditions. The objective of the present study was to gain deeper knowledge about the metabolic processes involved in the NASH animal model, and particularly in the effect of PH by using metabolomics. For achieving such information, twelve 8-week-old male C57BL/6 J mice, fed commercial chow (control diet) or methionine and choline-Deficient diet (MCD) for three weeks were subjected to PH and sacrificed 2 weeks later. Livers were removed and submitted to metabolic profiling analysis through RP-LC/MS (qTOF), GC/MS (qTOF) and CE/MS(TOF). More than 3000 different features were detected and repeated measurements one-way ANOVA analysis was performed to unveil significant features. MCD diet induced changes (p < 0.05) in 46% of the detected features, whereas PH provoked significant changes in 85% of them. Most of the changes were detected through LC/MS and were associated to lipid metabolism. However, changes of metabolites virtually related to other metabolic routes (amino acids, carbohydrates, nucleotides) were found altered and detected by CE/MS and GC/MS. The changes associated to PH show a similar trend regardless of the diet, but in the context of the diet deficient in methionine and choline we have found results that point to a different ratio glycolysis/tricarboxylic acid cycle. Moreover, in the NASH model, the regeneration of the liver structures occurs at the expense of an increased phosphatidylethanolamines/phosphatidylcholines ratio.

Ectopic localization of autophagosome in fatty liver is a key factor for liver regeneration

Autophagy has a critical role in liver regeneration. However, no studies have demonstrated autophagic flux in the regenerating fatty liver. The aim of this study was to clarify the dynamics of autophagy in the regeneration of the fatty liver. Following 70% partial hepatectomy (PH) in db/db fatty mice, which is a non-alcoholic fatty liver disease (NAFLD) model, we investigated the survival rate and recovery of liver volume. Histological examination of the regenerating liver was examined using electron microscopy. The 7-day survival rate after PH in db/db mice was 20%, which was significantly lower than that in control mice (P< .01). Liver regeneration within 48 h after PH was significantly impaired in db/db mice (P< .05). The number of proliferating cell nuclear antigen (PCNA) positive cells and the expression levels of cell-cycle markers cyclins D, E, and A were lower in db/db mice compared with controls. In the regenerating liver, LC3-II level was higher in db/db mice, but p62 expression was increased and cathepsin D expression, a marker of autophagolysosome proteolysis, was decreased compared with controls. Additionally, electronic microscopy revealed that autophagosomes during liver regeneration in db/db mice were mainly located in lipid droplets. Our findings indicate that the different localization of autophagosomes in db/db mice compared with controls led to impairment of liver regeneration in the fatty liver.

Hepatic CYP1A2 activity in liver tumors and the implications for preoperative volume-function analysis

Dynamic liver function assessment by the [¹³C]methacetin maximal liver function capacity (LiMAx) test reflects the overall hepatic cytochrome P-450 (CYP) 1A2 activity. One proven strategy for preoperative risk assessment in liver surgery includes the combined assessment of the dynamic liver function by the LiMAx test, the volumetric analysis of the liver, and calculation of future liver remnant function. This so-called volume-function analysis assumes that the remaining CYP1A2 activity in any tumor lesion is zero. The here presented study aims to assess the remaining CYP1A2 activities in different hepatic tumor lesions and its consequences for the preoperative volume-function analysis in patients undergoing liver surgery. The CYP1A2 activity analysis of neoplastic lesions and adjacent nontumor liver tissue from resected tumor specimens revealed a significantly higher CYP1A2 activity (median, interquartile range) in nontumor tissues (35.5, 15.9-54.4 µU/mg) compared with hepatocellular adenomas (7.35, 1.2-32.5 µU/mg), hepatocellular carcinomas (0.18, 0.0-2.0 µU/mg), or colorectal liver metastasis (0.17, 0.0-2.1 µU/mg). In nontumor liver tissue, a gradual decline in CYP1A2 activity with exacerbating fibrosis was observed. The CYP1A2 activity differences were also reflected in CYP1A2 protein signals in the assessed hepatic tissues. Volume-function analysis showed a minimal deviation compared with the current standard calculation for hepatocellular carcinomas or colorectal liver metastasis (<1% difference), whereas a difference of 11.9% was observed for hepatocellular adenomas. These findings are important for a refined preoperative volume-function analysis and improved surgical risk assessment in hepatocellular adenoma cases with low LiMAx values. NEW & NOTEWORTHY The cytochrome P-450 (CYP) 1A2-dependent maximal liver function capacity test reflects the overall functional capacity of the liver. To which extent hepatocellular tumors harbor CYP1A2 activity and thus contribute to the maximal liver function capacity test outcome is unknown. We here show that hepatocellular adenomas but not hepatocellular carcinomas or colorectal liver metastasis contain significant residual CYP1A2 activity. These findings are important for an improved preoperative volume-function analysis and an accurate surgical risk assessment in hepatocellular adenoma cases.

Differential Effects of a Glucagon-Like Peptide 1 Receptor Agonist in Non-Alcoholic Fatty Liver Disease and in Response to Hepatectomy

Non-alcoholic fatty liver disease (NAFLD) is associated with post-operative liver failure (PLF) and impaired liver regeneration. We investigated the effects of a glucagon-like peptide-1 (GLP-1) receptor agonist on NAFLD, PLF and liver regeneration in mice fed chow diet or methionine/choline-deficient diet (MCD) or high fat diet (HFD). Fc-GLP-1 decreased transaminases, reduced intrahepatic triglycerides (TG) and improved MCD-induced liver dysfuction. Macrophage/Kupffer cell-related markers were also reduced although Fc-GLP-1 increased expression of genes related to natural killer (NK), cytotoxic T lymphocytes and hepatic stellate cell (HSC) activation. After partial hepatectomy (PH), survival rates increased in mice receiving Fc-GLP-1 on chow or MCD diet. However, the benefit of Fc-GLP-1 on NASH-like features was attenuated 2 weeks post-PH and liver mass restoration was not improved. At this time-period, markers of NK cells and cytotoxic T lymphocytes were further elevated in Fc-GLP-1 treated mice. Increased HSC related gene expression in livers was observed together with decreased retinyl ester content and increased retinal and retinoic acid, reflecting HSC activation. Similar effects were found in mice fed HFD receiving Fc-GLP-1. Our results shed light on the differential effects of a long-acting GLP-1R agonist in improving NAFLD and PLF, but not enhancing liver regeneration in mice.

Randomized clinical trial comparing liver resection with and without perioperative assessment of liver function

Background

Liver function tests may help to predict outcomes after liver surgery. The aim of this study was to evaluate the clinical impact on postoperative outcome and patient management of perioperative liver function testing using the LiMAx^® test.

Methods

A multicentre RCT was conducted in six academic liver centres. Patients with intrahepatic tumours scheduled for open liver resection of at least one segment were eligible. Patients were randomized to undergo additional perioperative liver function tests (LiMAx^® group) or standard care (control group). Patients in the intervention arm received two perioperative LiMAx^® tests, one before the operation for surgical planning and another after surgery for postoperative management. The primary endpoint was the proportion of patients transferred directly to a general ward. Secondary endpoints were severe complications, length of hospital stay (LOS) and length of intermediate care/ICU (LOI) stay.

Results

Some 148 patients were randomized. Thirty‐six of 58 patients (62 per cent) in the LiMAx^® group were transferred directly to a general ward, compared with one of 60 (2 per cent) in the control group (P < 0·001). The rate of severe complications was significantly lower in the LiMAx^® group (14 per cent versus 28 per cent in the control group; P = 0·022). LOS and LOI were significantly shorter in the LiMAx^® group (LOS: 10·6 versus 13·3 days respectively, P = 0·012; LOI: 0·8 versus 3·0 days, P < 0·001).

Conclusion

Perioperative use of the LiMAx^® test improves postoperative management and reduces the incidence of severe complications after liver surgery. Registration number: NCT01785082 ( https://clinicaltrials.gov).

Fibroblast growth factors 19 and 21 in acute liver damage

Currently there are very few pharmacological options available to treat acute liver injury. Because its natural exposure to noxious stimuli the liver has developed a strong endogenous hepatoprotective capacity. Indeed, experimental evidence exposed a variety of endogenous hepatic and systemic responses naturally activated to protect the hepatic parenchyma and to foster liver regeneration, therefore preserving individual's survival. The fibroblast growth factor (FGF) family encompasses a range of polypeptides with important effects on cellular differentiation, growth survival and metabolic regulation in adult organisms. Among these FGFs, FGF19 and FGF21 are endocrine hormones that profoundly influence systemic metabolism but also exert important hepatoprotective activities. In this review, we revisit the biology of these factors and highlight their potential application for the clinical management of acute liver injury.

Mesenchymal stem cells seeded on a human amniotic membrane improve liver regeneration and mouse survival after extended hepatectomy

Liver failure remains the leading cause of post-operative mortality after hepatectomy. This study investigated the effect of treatment with allogenic mesenchymal stem cells (MSCs) on survival and liver regeneration 48 hr and 7 days after 80% hepatectomy in C57Bl/6 mice. To optimize their biodistribution, MSCs were grown on acellular human amniotic membranes (HAM) and applied as a patch on the remnant liver. This approach was compared with MSC infusion and HAM patch alone. Hepatectomized mice without any treatment were used as control group. Survival rate was calculated and biological and histopathological parameters were analysed to monitor liver function and regeneration. MSCs grown on HAM retained their ability to proliferate, to differentiate into osteoblasts and adipocytes and to respond to pro-inflammatory stimuli. Extended hepatectomy (80%) led to liver failure that resulted in death within 72 hr in 76% of mice. MSC infusion showed an early but transitory positive effect on survival. MSC/HAM patches stimulated regeneration and significantly improved survival rate (54% vs. 24% in the control group at 7 days). They also decreased the severity of hepatectomy-induced steatosis, suggesting a modulation of lipid metabolism in hepatocytes. MSCs were still present on HAM at Days 2 and 7 posthepatectomy. In conclusion, engineered tissue constructs that combine MSCs and HAM improve survival and liver regeneration after 80% hepatectomy in mice. These encouraging results pave the way to potential clinical application.

Feasibility of modified Dixon MRI techniques for hepatic fat quantification in hepatic disorders: validation with MRS and histology

OBJECTIVE

To assess the feasibility of proton density fat fraction (PDFF) MRI for estimating hepatic fat fraction with magnetic resonance spectroscopy (MRS) and histology as references and to investigate intrahepatic fat distribution and variability.

METHODS

Between November 2014 and September 2015, 85 adults (48 males, 47 females) who underwent MRI-PDFF (n = 139), MRS-PDFF (n = 49) and liver biopsy (n = 29) were enrolled in this study. Data were compared using linear regression. MRI-PDFF and standard deviations (variability) and differences between maximum and minimum PDFF (PDFF range) for whole liver, the lobes, and segment levels were calculated for each subject.

RESULTS

Whole-liver MRI-PDFF showed good correlation with MRS-PDFF (r = 0.961) and histologic degree of hepatic steatosis (σ = 0.809). Hepatic fat fraction is different between lobes and segments. Mean PDFF and mean PDFF range of the right lobe were higher than for the left lobe, whereas variability in the right lobe was lower than in the left lobe.

CONCLUSION

MRI-PDFF is an accurate non-invasive method for quantifying hepatic fat for various hepatic disorders, and may be preferable for measuring fat fraction in the right liver for more precise values in longitudinal monitoring, while avoiding FF measurement in the left liver. Advances in knowledge: MRI-PDFF provides a non-invasive and accurate quantification of hepatic steatosis in various hepatic disorders. It would be preferable to measure FF in the right liver than in the left liver.

Bile acids, FGF15/19 and liver regeneration: From mechanisms to clinical applications

The liver has an extraordinary regenerative capacity rapidly triggered upon injury or resection. This response is intrinsically adjusted in its initiation and termination, a property termed the "hepatostat". Several molecules have been involved in liver regeneration, and among them bile acids may play a central role. Intrahepatic levels of bile acids rapidly increase after resection. Through the activation of farnesoid X receptor (FXR), bile acids regulate their hepatic metabolism and also promote hepatocellular proliferation. FXR is also expressed in enterocytes, where bile acids stimulate the expression of fibroblast growth factor 15/19 (FGF15/19), which is released to the portal blood. Through the activation of FGFR4 on hepatocytes FGF15/19 regulates bile acids synthesis and finely tunes liver regeneration as part of the "hepatostat". Here we review the experimental evidences supporting the relevance of the FXR-FGF15/19-FGFR4 axis in liver regeneration and discuss potential therapeutic applications of FGF15/19 in the prevention of liver failure. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.

A novel glucagon-like peptide 1/glucagon receptor dual agonist improves steatohepatitis and liver regeneration in mice

Because nonalcoholic steatohepatitis (NASH) is associated with impaired liver regeneration, we investigated the effects of G49, a dual glucagon-like peptide-1/glucagon receptor agonist, on NASH and hepatic regeneration. C57Bl/6 mice fed chow or a methionine and choline-deficient (MCD) diet for 1 week were divided into 4 groups: control (chow diet), MCD diet, chow diet plus G49, and M+G49 (MCD diet plus G49). Mice fed a high-fat diet (HFD) for 10 weeks were divided into groups: HFD and H+G49 (HFD plus G49). Following 2 (MCD groups) or 3 (HFD groups) weeks of treatment with G49, partial hepatectomy (PH) was performed, and all mice were maintained on the same treatment schedule for 2 additional weeks. Analysis of liver function, hepatic regeneration, and comprehensive genomic and metabolic profiling were conducted. NASH was ameliorated in the M+G49 group, manifested by reduced inflammation, steatosis, oxidative stress, and apoptosis and increased mitochondrial biogenesis. G49 treatment was also associated with replenishment of intrahepatic glucose due to enhanced gluconeogenesis and reduced glucose use through the pentose phosphate cycle and oxidative metabolism. Following PH, G49 treatment increased survival, restored the cytokine-mediated priming phase, and enhanced the proliferative capacity and hepatic regeneration ratio in mice on the MCD diet. NASH markers remained decreased in M+G49 mice after PH, and glucose use was shifted to the pentose phosphate cycle and oxidative metabolism. G49 administered immediately after PH was also effective at alleviating the pathological changes induced by the MCD diet. Benefits in terms of liver regeneration were also found in mice fed HFD and treated with G49.

CONCLUSION

Dual-acting glucagon-like peptide-1/glucagon receptor agonists such as G49 represent a novel therapeutic approach for patients with NASH and particularly those requiring PH. (Hepatology 2017;65:950-968).

Application of the Liver Maximum Function Capacity Test in Acute Liver Failure: A Helpful Tool for Decision-Making in Liver Transplantation?

Background. Despite aggressive intensive medical management acute liver failure (ALF) may require high-urgency liver transplantation (LTx). Available prognostic scores do not apply for all patients; reliable tools to identify individuals in need of LTx are highly required. The liver maximum function capacity test (LiMAx) might represent an appropriate option. Referring to a case of ALF after Amanita phalloides-intoxication the potential of the LiMAx-test in this setting is discussed. Presentation of Case. LiMAx was performed in a 27-year-old patient prior to and after high-urgency LTx. In accordance with clinical appearance of hepatic encephalopathy, coagulopathy, and acute kidney failure, the LiMAx-test constituted a fulminant course of ALF with hardly any detectable metabolic activity. Following LTx with a marginal donor organ (95% hepatosteatosis), uptake of liver function was demonstrated by postoperative increase of the LiMAx-value. The patient was discharged from hospital on postoperative day 26. Discussion. ALF often is associated with a critical state of the patient that requires almost immediate decision-making regarding further therapy. Application of a noninvasive liver function test might help to determine the prognosis of ALF and support decision-making for or against LTx as well as acceptance of a critical donor organ in case of a critically ill patient.

Fetuin A is a Predictor of Liver Fat in Preoperative Patients with Nonalcoholic Fatty Liver Disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) are frequent comorbidities in perioperative patients. However, the predictive role of the hepatokine fetuin A was not evaluated in this collective.

OBJECTIVE

To study fetuin A as predictor of NAFLD/NASH in preoperative patients.

METHODS

58 subjects were included. Fetuin A was studied in patients undergoing open abdominal surgery and in a subset with acute liver failure. Blood and liver specimens were sampled. NAFLD was histologically evaluated. Liver fat was additionally analyzed by an enzymatic approach, circulating fetuin A by enzyme linked-immunosorbent assay, fetuin A mRNA by reverse-transcription PCR.

RESULTS

Univariate correlation studies linked fetuin A to liver steatosis (r = 0.40, p = .029) and hepatocellular ballooning degeneration (r = 0.34, p = .026). Compared to non-NAFLD subjects fetuin A was increased in NAFLD (p = .009) and in NASH (p = .029). However, when corrected for main confounders by linear modeling, fetuin A remained related to hepatic steatosis, but not to ballooning degeneration or other NAFLD features. In support of this, biochemically analyzed liver lipids correlated with fetuin A in plasma (r = 0.34, p = .033) and with hepatic fetuin A mRNA (r = 0.54, p < .001). In addition, plasma fetuin A was related to hepatic mRNA (r = 0.32, p = .036), while circulating levels were reduced by 64% with acute liver failure (p < .001), confirming the liver as main fetuin A source.

CONCLUSION

Fetuin A is suggested as noninvasive biomarker of hepatic steatosis in preoperative settings.