Liver transplantation for nonalcoholic steatohepatitis: the new epidemic. Ann Surg. 2012;256:624-633. [PMID: 22964732 DOI: 10.1097/sla.0b013e31826b4b7e]

Donor information based prediction of early allograft dysfunction and outcome in liver transplantation

BACKGROUND & AIMS

Poor initial graft function was recently newly defined as early allograft dysfunction (EAD) [Olthoff KM, Kulik L, Samstein B, et al. Validation of a current definition of early allograft dysfunction in liver transplant recipients and analysis of risk factors. Liver Transpl 2010; 16: 943]. Aim of this analysis was to evaluate predictive donor information for development of EAD.

METHODS

Six hundred and seventy-eight consecutive adult patients (mean age 51.6 years; 60.3% men) who received a primary liver transplantation (LT) (09/2003-12/2011) were included. Standard donor data were correlated with EAD and outcome by univariable/multivariable logistic regression and Cox proportional hazards to identify prognostic donor factors after adjustment for recipient confounders. Estimates of relevant factors were utilized for construction of a new continuous risk index to develop EAD.

RESULTS

38.7% patients developed EAD. 30-day survival of grafts with and without EAD was 59.8% and 89.7% (P < 0.0001). 30-day survival of patients with and without EAD was 68.5% and 93.1% (P < 0.0001) respectively. Donor body mass index (P = 0.0112), gGT (P = 0.0471), macrosteatosis (P = 0.0006) and cold ischaemia time (CIT) (P = 0.0031) were predictors of EAD. Internal cross validation showed a high predictive value (c-index = 0.622).

CONCLUSIONS

Early allograft dysfunction correlates with early results of LT and can be predicted by donor data only. The newly introduced risk index potentially optimizes individual decisions to accept/decline high risk organs. Outcome of these organs might be improved by shortening CIT.

Increasing prevalence of nonalcoholic steatohepatitis as an indication for liver transplantation

BACKGROUND

In Ohio, the obesity rate has increased from 21.5% in 2000 to 30.1% in 2012. Nonalcoholic steatohepatitis is believed to be increasing as an indication for orthotopic liver transplantation.

METHODS

We evaluated the diagnosis of nonalcoholic steatohepatitis as an indication for orthotopic liver transplantation and ensuing outcomes relative to other common hepatic diseases requiring orthotopic liver transplantation in Ohio. We queried 2,356 patients with nonalcoholic steatohepatitis, alcoholic cirrhosis (ETOH), and hepatitis C cirrhosis from the Ohio Solid Organ Transplantation Consortium who were listed for and/or received an orthotopic liver transplant from 2000 to 2012.

RESULTS

The proportion of listed patients with nonalcoholic steatohepatitis increased from 0% to 26% and the proportion of transplanted patients increased from 0% to 23.4%. Compared with patients with hepatitis C and ETOH, patients with nonalcoholic steatohepatitis were older, and more likely to be white, and have private insurance (P < .05 for each). There was no difference in median waiting time among patients with nonalcoholic steatohepatitis, hepatitis C, and ETOH (P = .18) and Model for End-Stage Liver Disease scores at orthotopic liver transplantation among patients with nonalcoholic steatohepatitis, hepatitis C (P = .48), and ETOH (P = .27). Patient and graft survival after orthotopic liver transplantation was comparable between patients with nonalcoholic steatohepatitis and ETOH (P = .79 and P = .86, respectively); however, patients with nonalcoholic steatohepatitis had better patient and graft survival compared with patients with hepatitis C after orthotopic liver transplantation (P < .01 and P = .02, respectively). Additionally, body mass index had no influence on overall or graft survival for patients with nonalcoholic steatohepatitis undergoing orthotopic liver transplantation.

CONCLUSION

This study reflects the growing potential for transplantation in patients with fatty liver disease and suggests the outcomes are equivalent or superior to other common indications for orthotopic liver transplantation.

Pharmacological inhibition of the chemokine CXCL16 diminishes liver macrophage infiltration and steatohepatitis in chronic hepatic injury

Non-alcoholic fatty liver disease (NAFLD) is a major cause of morbidity and mortality in developed countries, resulting in steatohepatitis (NASH), fibrosis and eventually cirrhosis. Modulating inflammatory mediators such as chemokines may represent a novel therapeutic strategy for NAFLD. We recently demonstrated that the chemokine receptor CXCR6 promotes hepatic NKT cell accumulation, thereby controlling inflammation in experimental NAFLD. In this study, we first investigated human biopsies (n = 20), confirming that accumulation of inflammatory cells such as macrophages is a hallmark of progressive NAFLD. Moreover, CXCR6 gene expression correlated with the inflammatory activity (ALT levels) in human NAFLD. We then tested the hypothesis that pharmacological inhibition of CXCL16 might hold therapeutic potential in NAFLD, using mouse models of acute carbon tetrachloride (CCl4)- and chronic methionine-choline-deficient (MCD) diet-induced hepatic injury. Neutralizing CXCL16 by i.p. injection of anti-CXCL16 antibody inhibited the early intrahepatic NKT cell accumulation upon acute toxic injury in vivo. Weekly therapeutic anti-CXCL16 administrations during the last 3 weeks of 6 weeks MCD diet significantly decreased the infiltration of inflammatory macrophages into the liver and intrahepatic levels of inflammatory cytokines like TNF or MCP-1. Importantly, anti-CXCL16 treatment significantly reduced fatty liver degeneration upon MCD diet, as assessed by hepatic triglyceride levels, histological steatosis scoring and quantification of lipid droplets. Moreover, injured hepatocytes up-regulated CXCL16 expression, indicating that scavenging functions of CXCL16 might be additionally involved in the pathogenesis of NAFLD. Targeting CXCL16 might therefore represent a promising novel therapeutic approach for liver inflammation and steatohepatitis.

External vibration multi-directional ultrasound shearwave elastography (EVMUSE): application in liver fibrosis staging

Shear wave speed can be used to assess tissue elasticity, which is associated with tissue health. Ultrasound shear wave elastography techniques based on measuring the propagation speed of the shear waves induced by acoustic radiation force are becoming promising alternatives to biopsy in liver fibrosis staging. However, shear waves generated by such methods are typically very weak. Therefore, the penetration may become problematic, especially for overweight or obese patients. In this study, we developed a new method called external vibration multi-directional ultrasound shearwave elastography (EVMUSE), in which external vibration from a loudspeaker was used to generate a multi-directional shear wave field. A directional filter was then applied to separate the complex shear wave field into several shear wave fields propagating in different directions. A 2-D shear wave speed map was reconstructed from each individual shear wave field, and a final 2-D shear wave speed map was constructed by compounding these individual wave speed maps. The method was validated using two homogeneous phantoms and one multi-purpose tissue-mimicking phantom. Ten patients undergoing liver magnetic resonance elastography (MRE) were also studied with EVMUSE to compare results between the two methods. Phantom results showed EVMUSE was able to quantify tissue elasticity accurately with good penetration. In vivo EVMUSE results were well correlated with MRE results, indicating the promise of using EVMUSE for liver fibrosis staging.

Debate: A bridge too far--liver transplantation for nonalcoholic steatohepatitis will overwhelm the organ supply

The obesity epidemic is one of the greatest health challenges currently facing the general population, and it will have a major impact on LT because of the associated rise in the incidence of NASH and NASH-related HCC. There is already a severe shortage of available liver allografts, which will be exacerbated by an increased demand for LT with the rising incidence of obesity-related liver disease. Because the obesity crisis also impacts the availability of suitable living and deceased organ donors, the impact will be far more significant. Research and public health initiatives aimed at further elucidating and counteracting obesity in both adults and especially children is paramount.

Living donor liver transplantation for non-alcoholic steatohepatitis: A single center experience

AIM

The number of patients referred for liver transplantation (LT) with non-alcoholic steatohepatitis (NASH) continues to increase, but information about living donor liver transplantation (LDLT) for NASH is scarce. We conducted this study to document the details of LDLT for NASH in a Japanese LT center.

METHODS

Among all LDLT recipients in our institution from March 1996 to March 2013 (n = 425), we identified seven patients that underwent LDLT for NASH.

RESULTS

Of all the seven recipients, most of the patients (86%) were obese. The median follow-up period post-LDLT was 5.3 years. All were alive at the last follow-up. Recurrent NASH was detected in one patient (14%), and no recurrent hepatic steatosis was detected among the remaining six recipients on prospectively performed ultrasonography. No significant comorbidities were observed following donor surgery among the respective living donors during the follow-up period. We also retrospectively reviewed 22 patients with NASH-related end-stage liver disease (ESLD) who were evaluated but rejected for LDLT during the same period. The reasons for rejection for LDLT were presumably associated with the nature of NAFLD/NASH in either potential recipients or donors.

CONCLUSION

The post-transplant outcome of LDLT for NASH-related ESLD in our institution was feasible, although the sample size was small. Further studies in a larger patient cohort are warranted to investigate the long-term outcome of LDLT for NASH, both for recipients and living donors.

Weight gain after orthotopic liver transplantation: is nonalcoholic fatty liver disease cirrhosis a risk factor for greater weight gain?

Posttransplant weight gain is common after orthotopic liver transplantation. We sought to determine the extent of weight gain at 5 years after transplantation in patients with nonalcoholic fatty liver disease (NAFLD) cirrhosis versus patients with other types of cirrhosis (non-NAFLD). We studied 126 liver transplants performed between 2005 and 2007 at Saint Luc Hospital, University of Montreal. Seventeen of the 126 patients (13.5%) had NAFLD cirrhosis. Ascites volume was difficult to assess, so we used the body mass index (BMI) at 3 months as the reference BMI. All patients gained weight after transplantation, but BMI increased significantly more and earlier among the NAFLD patients [4.8 versus 1.5 kg/m(2) at 1 year (P = 0.001), 5.0 versus 2.3 kg/m(2) at 2 years (P = 0.01), and 5.6 versus 2.6 kg/m(2) at 5 years (P = 0.009)] in comparison with non-NAFLD patients in unadjusted analyses. The greatest BMI increase over time was investigated with univariate and multivariate logistic regression analyses. The BMI increase was divided into tertiles for each period of time observed. The greatest BMI increase over time was defined as the top tertile of BMI increase. After adjustments for potential confounders (ie, total cholesterol, diabetes, and length of hospital stay), NAFLD was no longer associated with a risk of a greater BMI increase [odds ratio (OR) = 3.73 at 1 year (P = 0.11), OR = 2.15 at 2 years (P = 0.34), and OR = 2.87 at 5 years (P = 0.30)]. These findings suggest the need for multidisciplinary, early, and close weight monitoring for all patients. All patients could benefit from pretransplant counseling regarding weight gain and its consequences.

Early life exposure to maternal insulin resistance has persistent effects on hepatic NAFLD in juvenile nonhuman primates

The origins of nonalcoholic fatty liver disease (NAFLD) may lie in early intrauterine exposures. Here we examined the maternal response to chronic maternal high-fat (HF) diet and the impact of postweaning healthy diet on mechanisms for NAFLD development in juvenile nonhuman primate (NHP) offspring at 1 year of age. Pregnant females on HF diet were segregated as insulin resistant (IR; HF+IR) or insulin sensitive (IS; HF+IS) compared with control (CON)-fed mothers. HF+IR mothers have increased body mass, higher triglycerides, and increased placental cytokines. At weaning, offspring were placed on a CON or HF diet. Only offspring from HF+IR mothers had increased liver triglycerides and upregulated pathways for hepatic de novo lipid synthesis and inflammation that was irreversible upon switching to a healthy diet. These juvenile livers also showed a combination of classical and alternatively activated hepatic macrophages and natural killer T cells, in the absence of obesity or insulin resistance. Our findings suggest that maternal insulin resistance, including elevated triglycerides, insulin, and weight gain, initiates dysregulation of the juvenile hepatic immune system and development of de novo lipogenic pathways that persist in vitro and may be an irreversible "first hit" in the pathogenesis of NAFLD in NHP.

Liver disease in the morbidly obese: a review of 1000 consecutive patients undergoing weight loss surgery

BACKGROUND

Liver disease among the morbidly obese is increasingly prevalent, contributing to significant morbidity. Obesity-related liver pathologies including nonalcoholic steatohepatitis (NASH) have become a leading cause for liver transplant. However, risk factors for developing severe liver disease in the morbidly obese remain unknown. The objective of this study was to determine the frequency of abnormal liver pathology and any relationship to patient-related factors.

METHODS

One thousand consecutive patients undergoing weight loss surgery were reviewed. All patients had a liver biopsy at the time of surgery. Frequency of benign pathology, steatosis, NASH, and fibrosis on pathologic examination of liver biopsy specimens were recorded. Pathologic findings were compared and analyzed to age and body mass index (BMI) of all patients.

RESULTS

All patients in the study population had a BMI>35 kg/m2. Of these patients, 80.2% had liver disease related to obesity on pathology, including 65.9% with steatosis (grade 1-3), and 14.3% with NASH and/or fibrosis. Mean BMI of patients with liver disease was 48.1 compared to a BMI of 47.7 with benign pathology (P=.523). Mean age of patients with and without abnormal pathology was 48.3 and 47.3, respectively (P=.294).

CONCLUSION

Liver disease is highly prevalent in the obese, but is not associated with increased age or BMI. Although all morbidly obese patients appear at significant risk for developing severe liver pathology, further risk factors are unknown.

Association of non-alcoholic fatty liver disease with chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

Chronic kidney disease (CKD) is a frequent, under-recognized condition and a risk factor for renal failure and cardiovascular disease. Increasing evidence connects non-alcoholic fatty liver disease (NAFLD) to CKD. We conducted a meta-analysis to determine whether the presence and severity of NAFLD are associated with the presence and severity of CKD.

METHODS AND FINDINGS

English and non-English articles from international online databases from 1980 through January 31, 2014 were searched. Observational studies assessing NAFLD by histology, imaging, or biochemistry and defining CKD as either estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2 or proteinuria were included. Two reviewers extracted studies independently and in duplicate. Individual participant data (IPD) were solicited from all selected studies. Studies providing IPD were combined with studies providing only aggregate data with the two-stage method. Main outcomes were pooled using random-effects models. Sensitivity and subgroup analyses were used to explore sources of heterogeneity and the effect of potential confounders. The influences of age, whole-body/abdominal obesity, homeostasis model of insulin resistance (HOMA-IR), and duration of follow-up on effect estimates were assessed by meta-regression. Thirty-three studies (63,902 participants, 16 population-based and 17 hospital-based, 20 cross-sectional, and 13 longitudinal) were included. For 20 studies (61% of included studies, 11 cross-sectional and nine longitudinal, 29,282 participants), we obtained IPD. NAFLD was associated with an increased risk of prevalent (odds ratio [OR] 2.12, 95% CI 1.69-2.66) and incident (hazard ratio [HR] 1.79, 95% CI 1.65-1.95) CKD. Non-alcoholic steatohepatitis (NASH) was associated with a higher prevalence (OR 2.53, 95% CI 1.58-4.05) and incidence (HR 2.12, 95% CI 1.42-3.17) of CKD than simple steatosis. Advanced fibrosis was associated with a higher prevalence (OR 5.20, 95% CI 3.14-8.61) and incidence (HR 3.29, 95% CI 2.30-4.71) of CKD than non-advanced fibrosis. In all analyses, the magnitude and direction of effects remained unaffected by diabetes status, after adjustment for other risk factors, and in other subgroup and meta-regression analyses. In cross-sectional and longitudinal studies, the severity of NAFLD was positively associated with CKD stages. Limitations of analysis are the relatively small size of studies utilizing liver histology and the suboptimal sensitivity of ultrasound and biochemistry for NAFLD detection in population-based studies.

CONCLUSION

The presence and severity of NAFLD are associated with an increased risk and severity of CKD. Please see later in the article for the Editors' Summary.

Effects of resveratrol and other polyphenols in hepatic steatosis

Non-alcoholic fatty liver disease covers a wide spectrum of liver pathologies which range from simple steatosis to non-alcoholic steatohepatitis. Polyphenols are members of a very large family of plant-derived compounds that can have beneficial effects on human health, and thus their study has become an increasingly important area of human nutrition research. The aim of the present review is to compile published data concerning the effects of both isolated polyphenols as well as polyphenol extracts, on hepatocyte and liver fat accumulation under different steatosis-inducing conditions. The results reported clearly show that this group of biomolecules is able to reduce fat accumulation, but further studies are needed to establish the optimal dose and treatment period length. With regard to the potential mechanisms of action, there is a good consensus. The anti-lipidogenic effect of polyphenols is mainly due to reduced fatty acid and triacylglycerol synthesis, increased in fatty acid oxidation, and reduced of oxidative stress and inflammation. As a general conclusion, it can be stated that polyphenols are biomolecules which produce hepatoprotective effects. To date, these beneficial effects have been demonstrated in cultured cells and animal models. Thus, studies performed in humans are needed before these molecules can be considered as truly useful tools in the prevention of liver steatosis.

Metabolic syndrome and non-alcoholic fatty liver disease in liver surgery: The new scourges?

The aim of this topic highlight is to review relevant evidence regarding the influence of the metabolic syndrome (MS) and its associated liver manifestation, non-alcoholic fatty liver disease (NAFLD), on the development of liver cancer as well as their impact on the results of major liver surgery. MS and NAFLD, whose incidences are significantly increasing in Western countries, are leading to a changing profile of the patients undergoing liver surgery. A MEDLINE search was performed for relevant articles using the key words "metabolic syndrome", "liver resection", "liver transplantation", "non alcoholic fatty liver disease", "non-alcoholic steatohepatitis" and "liver cancer". On one hand, the MS favors the development of primary liver malignancies (hepatocellular carcinoma and cholangiocarcinoma) either through NAFLD liver parenchymal alterations (steatosis, steatohepatitis, fibrosis) or in the absence of significant underlying liver parenchyma changes. Also, the existence of NAFLD may have a specific impact on colorectal liver metastases recurrence. On the other hand, the postoperative period following partial liver resection and liver transplantation is at increased risk of both postoperative complications and mortality. These deleterious effects seem to be related to the existence of liver specific complications but also higher cardio-vascular sensitivity in a setting of MS/NAFLD. Finally, the long-term prognosis after curative surgery joins that of patients operated on with other types of underlying liver diseases. An increased rate of patients with MS/NAFLD referred to hepatobiliary units has to be expected. The higher operative risk observed in this subset of patients will require specific improvements in their perioperative management.

Where to begin and where to end? Preoperative assessment for patients undergoing metabolic surgery

Bariatric surgery is the most effective treatment of obesity and its associated diseases like type 2 diabetes mellitus. Given the obesity epidemic and the efficacy of surgical treatment, the number of surgical weight loss procedures has grown in recent years. Nevertheless, there is little consensus regarding the extent of preoperative investigations required prior to patients undergoing surgery. This article aims to discuss the available evidence on which preoperative tests are useful for the detection and treatment of conditions such as venous thromboembolism, obstructive sleep apnea syndrome and Helicobacter pylori-positive gastritis prior to an operation. The present literature suggests that only a few preoperative investigations are essential, but that preoperative multidisciplinary care is beneficial.

Outcomes of liver transplantation for nonalcoholic steatohepatitis: a systematic review and meta-analysis

BACKGROUND & AIMS

Little is known about outcomes of patients with nonalcoholic steatohepatitis (NASH) who receive liver transplants. We performed a systematic review and meta-analysis to estimate post-transplant outcomes, survival times, and mortality from cardiovascular complications, sepsis, and graft failure in these patients.

METHODS

We searched PubMed and EMBASE, and Cochrane library and Web of Science databases for studies published through September 1, 2012 of patients who underwent liver transplantation for NASH or nonalcoholic fatty liver disease (NAFLD). All original studies from single institutions that reported outcomes of patients with or without NASH after liver transplantation were considered. Odds ratios (ORs) were calculated for patients with NASH, compared with patients without NASH; 95% confidence intervals (CIs) were calculated.

RESULTS

Our final analysis included 9 publications, on 717 patients with NASH and 3520 without, all of whom underwent liver transplantation. Similar proportions of patients with and without NASH who received liver transplants survived for 1, 3, and 5 years (OR for survival of patient with NASH 1 year after liver transplantation, 0.77; 95% CI, 0.59-1.00; P = .05; OR 3 years after transplantation, 0.97; 95% CI, 0.67-1.40; P = .86; OR 5 years after transplantation, 1.09; 95% CI, 0.77-1.56; P = .63). Patients with NASH had a greater risk of death from cardiovascular complications after liver transplantation (OR, 1.65; 95% CI, 1.01-2.70; P = .05) and from sepsis (OR, 1.71; 95% CI, 1.17-2.50; P = .006). However, patients with NASH were at lower risk of graft failure compared with patients without NASH (OR, 0.21; 95% CI, 0.05-0.89; P = .03).

CONCLUSIONS

Similar proportions of patients with and without NASH survive for 1, 3, and 5 years after liver transplantation. However, patients with NASH are more likely to die from cardiovascular complications or sepsis. More attention and careful consideration are therefore required in selecting patients with NASH for liver transplantation, along with aggressive management of cardiovascular complications and sepsis after transplantation.

Hepatic steatosis and steatohepatitis: Are they really two distinct entities?

Non-alcoholic fatty liver disease affects nearly 30% of Americans. A histopathological spectrum exists from simple steatosis to NASH which may progress to cirrhosis and HCC. NASH is currently the third most common indication for liver transplant with increasing incidence. Steatosis can be considered the hepatic manifestation of the metabolic syndrome as insulin resistance is a major risk factor for its development. While liver biopsy is the gold standard for diagnosis, non-invasive methods are currently being developed to appropriately determine who needs histologic evaluation. Management focuses on mitigation of risk factors, since targeted therapies to halt progression of fibrosis have not been validated. Simple steatosis does not affect overall survival, but NASH conveys increased mortality. Because of this, non-invasive strategies to diagnose patients and management algorithms are needed. This review supports the definitions of simple steatosis and NASH as two distinct entities based on pathophysiology, diagnosis, management, and prognosis.

Nonalcoholic fatty liver disease epidemic and its implications for liver transplantation

Nonalcoholic steatohepatitis (NASH) is increasingly recognized as the most common chronic liver disease worldwide. The aim of this study is to investigate the transplantation trends of liver transplant (LT) recipients with NASH. Using the United Network for Organ Sharing database, we found a steady increase in LT rate especially in those more than 65 years old. We identified differences across ethnic groups and United Network for Organ Sharing regions. This study highlights the impact of the rising prevalence of NASH on the demand for LT and provides invaluable information to healthcare policymakers and the transplant community about the target groups and geographic location for focused and early intervention.

Developmental origins of nonalcoholic fatty liver disease

Obese pregnant women may transmit their metabolic phenotype to offspring, leading to a cycle of obesity and diabetes over generations. Early childhood obesity predicts nonalcoholic fatty liver disease (NAFLD), the most common chronic human liver disease. The fetus may be vulnerable to steatosis because immature fetal adipose depots are not available to buffer the excess transplacental lipid delivery in maternal obesity. In animal models, in utero high-fat diet exposure results in an increase in the accumulation of liver triglycerides in offspring and increased hepatic oxidative stress and apoptosis, perhaps priming the liver for later development of NAFLD. Innate immune dysfunction and necroinflammatory changes have been observed in postnatal offspring liver of animals born to high-fat-fed dams. Postweaning, livers of offspring exposed to maternal high-fat feeding in utero share pathophysiologic features with human NAFLD, including increased de novo lipogenesis and decreased free fatty acid oxidation. Human studies using magnetic resonance imaging have shown that maternal BMI predicts infant intrahepatocellular lipid storage, as seen in animal models. The generational transfer of NAFLD may occur via epigenetic changes in offspring liver. Transmission of microbiota from mother to infant may impact energy retention and immune function that contribute to a predisposition to NAFLD.

Non-alcoholic fatty liver disease and liver transplantation: Outcomes and advances

Non-alcoholic fatty liver disease (NAFLD) is one of the most prevalent causes of chronic liver disease worldwide. In the last decade it has become the third most common indication for liver transplantation in the United States. Increasing prevalence of NAFLD in the general population also poses a risk to organ donation, as allograft steatosis can be associated with non-function of the graft. Post-transplant survival is comparable between NAFLD and non-NAFLD causes of liver disease, although long term outcomes beyond 10 year are lacking. NAFLD can recur in the allograft frequently although thus far post transplant survival has not been impacted. De novo NAFLD can also occur in the allograft of patients transplanted for non-NAFLD liver disease. Predictors for NAFLD post-transplant recurrence include obesity, hyperlipidemia and diabetes as well as steroid dose after liver transplantation. A polymorphism in PNPLA3 that mediates triglyceride hydrolysis and is linked to pre-transplant risk of obesity and NAFLD has also been linked to post transplant NAFLD risk. Although immunosuppression side effects potentiate obesity and the metabolic syndrome, studies of immunosuppression modulation and trials of specific immunosuppression regimens post-transplant are lacking in this patient population. Based on pre-transplant data, sustained weight loss through diet and exercise is the most effective therapy for NAFLD. Other agents occasionally utilized in NAFLD prior to transplantation include vitamin E and insulin-sensitizing agents. Studies of these therapies are lacking in the post-transplant population. A multimodality and multidisciplinary approach to treatment should be utilized in management of post-transplant NAFLD.

Rapid chromatographic method to decipher distinct alterations in lipid classes in NAFLD/NASH

AIM: To establish a simple method to quantify lipid classes in liver diseases and to decipher the lipid profile in p62/IMP2-2/IGF2BP2-2 transgenic mice.

METHODS: Liver-specific overexpression of the insulin-like growth factor 2 mRNA binding protein p62/IMP2-2/IGF2BP2-2 was used as a model for steatosis. Steatohepatitis was induced by feeding a methionine-choline deficient diet. Steatosis was assessed histologically. For thin layer chromatographic analysis, lipids were extracted from freeze-dried tissues by hexane/2-propanol, dried, redissolved, and chromatographically separated by a two-solvent system. Dilution series of lipid standards were chromatographed, detected, and quantified. The detection was performed by either 2’,7’-dichlorofluoresceine or a sulfuric acid/ethanol mixture.

RESULTS: Histological analyses confirmed steatosis and steatohepatitis development. The extraction, chromatographic, and detection method showed high inter-assay reproducibility and allowed quantification of the different lipid classes. The analyses confirmed an increase of triglycerides and phosphatidylethanolamine and a decrease in phosphatidylcholine in the methionine-choline deficient diet. The method was used for the first time to asses the lipid classes induced in the p62-overexpressing mouse model and showed a significant increase in all detected lipid species with a prominent increase of triglycerides by 2-fold. Interestingly, the ratio of phosphatidylcholine to phosphatidylethanolamine was decreased, as previously suggested as a marker in the progression from steatosis to steatohepatitis.

CONCLUSION: The thin layer chromatography analysis allows a reliable quantification of lipid classes and provides detailed insight into the lipogenic effect of p62.

Prediction of non-alcoholic fatty-liver disease and liver fat content by serum molecular lipids

AIMS/HYPOTHESIS

We examined whether analysis of lipids by ultra-performance liquid chromatography (UPLC) coupled to MS allows the development of a laboratory test for non-alcoholic fatty-liver disease (NAFLD), and how a lipid-profile biomarker compares with the prediction of NAFLD and liver-fat content based on routinely available clinical and laboratory data.

METHODS

We analysed the concentrations of molecular lipids by UPLC-MS in blood samples of 679 well-characterised individuals in whom liver-fat content was measured using proton magnetic resonance spectroscopy ((1)H-MRS) or liver biopsy. The participants were divided into biomarker-discovery (n = 287) and validation (n = 392) groups to build and validate the diagnostic models, respectively.

RESULTS

Individuals with NAFLD had increased triacylglycerols with low carbon number and double-bond content while lysophosphatidylcholines and ether phospholipids were diminished in those with NAFLD. A serum-lipid signature comprising three molecular lipids ('lipid triplet') was developed to estimate the percentage of liver fat. It had a sensitivity of 69.1% and specificity of 73.8% when applied for diagnosis of NAFLD in the validation series. The usefulness of the lipid triplet was demonstrated in a weight-loss intervention study.

CONCLUSIONS/INTERPRETATION

The liver-fat-biomarker signature based on molecular lipids may provide a non-invasive tool to diagnose NAFLD, in addition to highlighting lipid molecular pathways involved in the disease.

Simple noninvasive systems predict long-term outcomes of patients with nonalcoholic fatty liver disease

BACKGROUND & AIMS

Some patients with nonalcoholic fatty liver disease (NAFLD) develop liver-related complications and have higher mortality than other patients with NAFLD. We determined the accuracy of simple, noninvasive scoring systems in identification of patients at increased risk for liver-related complications or death.

METHODS

We performed a retrospective, international, multicenter cohort study of 320 patients diagnosed with NAFLD, based on liver biopsy analysis through 2002 and followed through 2011. Patients were assigned to mild-, intermediate-, or high-risk groups based on cutoff values for 2 of the following: NAFLD fibrosis score, aspartate aminotransferase/platelet ratio index, FIB-4 score, and BARD score. Outcomes included liver-related complications and death or liver transplantation. We used multivariate Cox proportional hazard regression analysis to adjust for relevant variables and calculate adjusted hazard ratios (aHRs).

RESULTS

During a median follow-up period of 104.8 months (range, 3-317 months), 14% of patients developed liver-related events and 13% died or underwent liver transplantation. The aHRs for liver-related events in the intermediate-risk and high-risk groups, compared with the low-risk group, were 7.7 (95% confidence interval [CI]: 1.4-42.7) and 34.2 (95% CI: 6.5-180.1), respectively, based on NAFLD fibrosis score; 8.8 (95% CI: 1.1-67.3) and 20.9 (95% CI: 2.6-165.3) based on the aspartate aminotransferase/platelet ratio index; and 6.2 (95% CI: 1.4-27.2) and 6.6 (95% CI: 1.4-31.1) based on the BARD score. The aHRs for death or liver transplantation in the intermediate-risk and high-risk groups compared with the low-risk group were 4.2 (95% CI: 1.3-13.8) and 9.8 (95% CI: 2.7-35.3), respectively, based on the NAFLD fibrosis scores. Based on aspartate aminotransferase/platelet ratio index and FIB-4 score, only the high-risk group had a greater risk of death or liver transplantation (aHR = 3.1; 95% CI: 1.1-8.4 and aHR = 6.6; 95% CI: 2.3-20.4, respectively).

CONCLUSIONS

Simple noninvasive scoring systems help identify patients with NAFLD who are at increased risk for liver-related complications or death. NAFLD fibrosis score appears to be the best indicator of patients at risk, based on HRs. The results of this study require external validation.

Comparable graft and patient survival in lean and obese liver transplant recipients

Obesity is among the great health problems facing Americans today. More than 32% of the US population is considered obese on the basis of a body mass index (BMI) exceeding 30 kg/m(2) . Obesity increases the risk for numerous perioperative complications, but how obesity affects the outcome of liver transplantation remains unclear. We compared graft/patient survival after orthotopic liver transplantation performed at the Cleveland Clinic between April 2005 and June 2011 in 2 groups: obese patients with a BMI ≥ 38 kg/m(2) and lean patients with a BMI between 20 and 26 kg/m(2) . We included 47 obese patients and 183 lean patients, whose demographics and baseline characteristics were well balanced after weighting with the inverse propensity score. After we controlled for observed confounding, no significant differences were observed in graft/patient survival between obese and lean patients (P = 0.30). The estimated hazard ratio for obese patients to experience graft failure or death was 1.19 [95% confidence interval (CI) = 0.85-1.67]. There were 134 patients who had follow-up for more than 3 years, and they included 27 obese patients and 107 lean patients. Within this subset, the odds of having metabolic syndrome were significantly greater for obese patients (46%) versus lean patients (21%; odds ratio = 4.76, 99.5% CI = 1.66-13.7, P < 0.001). However, no significant association between obesity and any other long-term adverse outcomes was found. In conclusion, this study shows that transplant outcomes were comparable for lean and obese recipients. We thus recommend that even morbid obesity per se should not exclude patients from consideration for transplantation.

Liver transplantation: past, present and future

The first human liver transplant operation was performed by Thomas Starzl in 1963. The next two decades were marked by difficulties with donor organ quality, recipient selection, operative and perioperative management, immunosuppression and infectious complications. Advances in each of these areas transformed liver transplantation from an experimental procedure to a standard treatment for end-stage liver disease and certain cancers. From the handful of pioneering programmes, liver transplantation has expanded to hundreds of programmes in >80 countries. 1-year patient survival rates have exceeded 80% and outcomes continue to improve. This success has created obstacles. Ongoing challenges of liver transplantation include those concerning donor organ shortages, recipients with more advanced disease at transplant, growing need for retransplantation, toxicities and adverse effects associated with long-term immunosuppression, obesity and NASH epidemics, HCV recurrence and the still inscrutable biology of hepatocellular carcinoma. This Perspectives summarizes this transformation over time and details some of the challenges ahead.

Gastrointestinal complications of obesity: non-alcoholic fatty liver disease (NAFLD) and its sequelae

Obesity is a major risk factor for malign and non-malign diseases of the gastrointestinal tract. Non-alcoholic fatty liver disease (NAFLD) is an outstanding example for the complex pathophysiology of the metabolic system and represents both source and consequence of the metabolic syndrome. NAFLD has a growing prevalence and will become the leading cause of advanced liver disease and cirrhosis. Obesity has a negative impact on NAFLD at all aspects and stages of the disease. The growing epidemic will strain health care resources and demands new concepts for prevention, screening and therapeutic approaches. A better understanding of the interplay of liver, gut and hormonal system is necessary for new insights in the underlying mechanisms of NAFLD and the metabolic syndrome including obesity. Identification of patients at risk for progressive liver disease will allow a better adaption of treatment strategies.