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Maliakkal BJ. Pathogenesis of non-alcoholic fatty liver disease and implications on cardiovascular outcomes in liver transplantation. Transl Gastroenterol Hepatol 2020; 5:36. [PMID: 32632387 DOI: 10.21037/tgh.2019.12.02] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 11/05/2019] [Indexed: 12/15/2022] Open
Abstract
Along with the obesity epidemic there has been a major increase in non-alcoholic fatty liver disease (NAFLD) prevalence, paralleling a steady increase in cirrhosis of the liver and hepatocellular cancer (HCC) related to NAFLD. Currently, NAFLD (related HCC and cirrhosis) is the second most common cause for liver transplantation (LT) and it is projected to take the top spot in the next 3-5 years. Patients with NAFLD cirrhosis and HCC have a unique set of comorbidities which potentially increases their risk for cardiovascular disease (CVD) and mortality. However, a review of the published data in NAFLD patients who undergo LT, does not paint a clear picture. While CVD is the most common cause of non-graft related mortality over the long-term, the short and intermediate-term survival post LT in NAFLD cirrhosis appears to be on par with other etiologies when age and comorbidities are factored. The cardiovascular complications are increased in the immediate post-transplant period but there is a shift from ischemic complications to arrhythmias and heart failure (HF). NAFLD recurs in 80-100% patients and occurs de novo in about 50% after LT, potentially impacting their long-term morbidity and mortality. This review summarizes the available data on CVD in NAFLD patients before and after LT, explains what is currently known about the epidemiology and pathogenesis of CVD in NAFLD and posits strategies to improve wait-list and post-transplant survival.
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Esler WP, Bence KK. Metabolic Targets in Nonalcoholic Fatty Liver Disease. Cell Mol Gastroenterol Hepatol 2019; 8:247-267. [PMID: 31004828 PMCID: PMC6698700 DOI: 10.1016/j.jcmgh.2019.04.007] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/09/2019] [Accepted: 04/11/2019] [Indexed: 12/18/2022]
Abstract
The prevalence and diagnosis of nonalcoholic fatty liver disease (NAFLD) is on the rise worldwide and currently has no FDA-approved pharmacotherapy. The increase in disease burden of NAFLD and a more severe form of this progressive liver disease, nonalcoholic steatohepatitis (NASH), largely mirrors the increase in obesity and type 2 diabetes (T2D) and reflects the hepatic manifestation of an altered metabolic state. Indeed, metabolic syndrome, defined as a constellation of obesity, insulin resistance, hyperglycemia, dyslipidemia and hypertension, is the major risk factor predisposing the NAFLD and NASH. There are multiple potential pharmacologic strategies to rebalance aspects of disordered metabolism in NAFLD. These include therapies aimed at reducing hepatic steatosis by directly modulating lipid metabolism within the liver, inhibiting fructose metabolism, altering delivery of free fatty acids from the adipose to the liver by targeting insulin resistance and/or adipose metabolism, modulating glycemia, and altering pleiotropic metabolic pathways simultaneously. Emerging data from human genetics also supports a role for metabolic drivers in NAFLD and risk for progression to NASH. In this review, we highlight the prominent metabolic drivers of NAFLD pathogenesis and discuss the major metabolic targets of NASH pharmacotherapy.
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Key Words
- acc, acetyl-coa carboxylase
- alt, alanine aminotransferase
- aso, anti-sense oligonucleotide
- ast, aspartate aminotransferase
- chrebp, carbohydrate response element binding protein
- ci, confidence interval
- dgat, diacylglycerol o-acyltransferase
- dnl, de novo lipogenesis
- fas, fatty acid synthase
- ffa, free fatty acid
- fgf, fibroblast growth factor
- fxr, farnesoid x receptor
- glp-1, glucagon-like peptide-1
- hdl, high-density lipoprotein
- homa-ir, homeostatic model assessment of insulin resistance
- ldl, low-density lipoprotein
- nafld, nonalcoholic fatty liver disease
- nas, nonalcoholic fatty liver disease activity score
- nash, nonalcoholic steatohepatitis
- or, odds ratio
- pdff, proton density fat fraction
- ppar, peroxisome proliferator-activated receptor
- sglt2, sodium glucose co-transporter 2
- srebp-1c, sterol regulatory element binding protein-1c
- t2d, type 2 diabetes
- t2dm, type 2 diabetes mellitus
- tg, triglyceride
- th, thyroid hormone
- thr, thyroid hormone receptor
- treg, regulatory t cells
- tzd, thiazolidinedione
- vldl, very low-density lipoprotein
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Affiliation(s)
- William P Esler
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts
| | - Kendra K Bence
- Internal Medicine Research Unit, Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts.
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Kennedy C, Redden D, Gray S, Eckhoff D, Massoud O, McGuire B, Alkurdi B, Bloomer J, DuBay DA. Equivalent survival following liver transplantation in patients with non-alcoholic steatohepatitis compared with patients with other liver diseases. HPB (Oxford) 2012; 14:625-34. [PMID: 22882200 PMCID: PMC3461389 DOI: 10.1111/j.1477-2574.2012.00497.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Orthotopic liver transplantation (LT) in non-alcoholic steatohepatitis (NASH) is increasing in parallel with the obesity epidemic. METHODS This study retrospectively reviewed the clinical outcomes of LTs in NASH (n = 129) and non-NASH (n = 775) aetiologies carried out at a single centre between 1999 and 2009. RESULTS Rates of 1-, 3- and 5-year overall survival in NASH (90%, 88% and 85%, respectively) were comparable with those in non-NASH (92%, 86% and 80%, respectively) patients. Mortality within 4 months of LT was twice as high in NASH as in non-NASH patients (8.5% vs. 4.2%; P = 0.04). Compared with non-NASH patients, post-LT mortality in NASH patients was more commonly caused by infectious (38% vs. 26%; P < 0.05) or cardiac (19% vs. 7%; P < 0.05) aetiologies. Five-year survival was lower in NASH patients with a high-risk phenotype (age >60 years, body mass index >30 kg/m(2), with hypertension and diabetes) than in NASH patients without these characteristics (72% vs. 87%; P = 0.02). Subgroup analyses revealed that 5-year overall survival in NASH was equivalent to that in Laennec's cirrhosis (85% vs. 80%; P 0.87), but lower than that in cirrhosis of cryptogenic aetiology (85% vs. 96%; P = 0.04). CONCLUSIONS Orthotopic LT in NASH was associated with increased early postoperative mortality, but 1-, 3- and 5-year overall survival rates were equivalent to those in non-NASH patients.
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Affiliation(s)
- Christopher Kennedy
- Transplant Surgery, Division of Abdominal Transplant, Department of SurgeryBirmingham, AL, USA
| | - David Redden
- Biostatistics Division, School of Public HealthBirmingham, AL, USA
| | - Stephen Gray
- Transplant Surgery, Division of Abdominal Transplant, Department of SurgeryBirmingham, AL, USA
| | - Devin Eckhoff
- Transplant Surgery, Division of Abdominal Transplant, Department of SurgeryBirmingham, AL, USA
| | - Omar Massoud
- Transplant Surgery, Division of Abdominal Transplant, Department of SurgeryBirmingham, AL, USA
| | - Brendan McGuire
- Transplant Surgery, Division of Abdominal Transplant, Department of SurgeryBirmingham, AL, USA
| | - Basem Alkurdi
- Transplant Surgery, Division of Abdominal Transplant, Department of SurgeryBirmingham, AL, USA
| | - Joseph Bloomer
- Transplant Surgery, Division of Abdominal Transplant, Department of SurgeryBirmingham, AL, USA
| | - Derek A DuBay
- Transplant Surgery, Division of Abdominal Transplant, Department of SurgeryBirmingham, AL, USA
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Abstract
Non-alcoholic fatty liver disease (NAFLD) refers to the accumulation of hepatic steatosis not due to excess alcohol consumption. The prevalence of NAFLD is up to 30% in developed countries and nearly 10% in developing nations, making NAFLD the most common liver condition in the world. The pathogenesis of NAFLD is related to insulin resistance and, thus, it is frequently found in individuals who have central obesity or diabetes. Insulin resistance and excess adiposity are associated with increased lipid influx into the liver and increased de novo hepatic lipogenesis, promoting hepatic triglyceride accumulation. Defects in lipid utilization via mitochondrial oxidation and lipid export may also contribute to hepatic lipid build-up. Adipocytokine alterations, lipotoxicity from saturated fatty acids and fructose have been all been implicated in causing hepatocyte injury in NAFLD through pathways involving oxidative and endoplasmic reticulum stress. Clinically, NAFLD is commonly asymptomatic and frequently detected incidentally by blood liver function tests or imaging performed for other reasons. Subjects with NAFLD have a higher mortality rate than the general population and are at increased risk of developing cardiovascular disease and diabetes in the future. Histologically, NAFLD occurs as a spectrum from mild hepatic steatosis only, to non-alcoholic steatohepatitis (NASH) characterized by hepatocellular injury and inflammation, to cirrhosis. A diagnosis of NASH with associated fibrosis heralds a more significant prognosis as it is more likely to progressive to cirrhosis with complications of hepatic failure and hepatocellular carcinoma. Currently, the diagnosis of NASH requires a liver biopsy, however, serum based markers of hepatocyte apoptosis such as cytokeratin-18 fragments offer promise as accurate non-invasive diagnostic tests. Treatment of NAFLD revolves around addressing concomitant metabolic risk factors and improving insulin resistance through weight loss measures and exercise. Insulin sensitizing agents such as pioglitazone and anti-oxidant agents such as vitamin E show some promise in improving liver histology in patients with NASH, however, the long-term benefit of these medications has not been demonstrated.
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Affiliation(s)
- Briohny W Smith
- School of Medicine and Pharmacology, Sir Charles Gairdner Hospital Unit, University of Western Australia, Nedlands, Australia
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Saigal S, Nayak NC, Jain D, Kumaran V, Mohanka R, Saraf N, Rastogi A, Mehta N, Nundy S, Soin A. Non-cirrhotic portal fibrosis related end stage liver disease in adults: evaluation from a study on living donor liver transplant recipients. Hepatol Int 2011; 5:882-9. [PMID: 21484137 DOI: 10.1007/s12072-010-9246-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2010] [Accepted: 12/20/2010] [Indexed: 11/30/2022]
Abstract
BACKGROUND That non-cirrhotic portal fibrosis (NCPF) can lead to end stage chronic liver disease (CLD) has been convincingly demonstrated only recently after the study of explant livers from clinically cirrhosis cases. AIMS This study attempted to determine the frequency of NCPF among adults transplanted for end stage CLD and to identify parameters for a pre-transplant diagnosis of NCPF. METHODS Several parameters were analyzed in three categories of cases: pure NCPF (n = 10), overlap NCPF (n = 10), and NAFLD cirrhosis controls (n = 44). Morphologic features of NCPF were looked for in explant livers of all these. RESULTS Explant livers in the pure NCPF group were non-cirrhotic and showed histologic features of NCPF. These features were also present in all cases of overlap NCPF in the background of established cirrhosis of other etiologies but absent in the NAFLD cirrhosis controls. Values of seven objective and two subjective parameters showed significant differences between pure NCPF and NAFLD control groups. Compared to NAFLD controls, the model for end stage liver disease (MELD) score, body mass index (BMI), bilirubin, albumin, aspartate amino transferase (AST), and international normalized ratio (INR) were significantly less, whereas variceal grade was higher in the pure NCPF group. CONCLUSIONS The study concludes that in our population, NCPF constitutes about 5% of the subset of end stage CLD considered eligible for liver transplantation (LT), presenting mostly as cryptogenic cirrhosis (CC). A diagnosis of NCPF should be considered when patients presumed to have cryptogenic or other cirrhosis become eligible for LT even in the presence of relatively well-preserved liver function and low MELD scores. End stage CLD manifests at earlier age, when cirrhosis of another etiology supervenes on pre-existent NCPF.
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Affiliation(s)
- Sanjiv Saigal
- Department of Liver Transplant, Sir Ganga Ram Hospital, New Delhi, India
| | - Nabeen C Nayak
- Department of Pathology, Sir Ganga Ram Hospital, New Delhi, India
| | - Deepali Jain
- Department of Pathology, Sir Ganga Ram Hospital, New Delhi, India.
| | - Vinay Kumaran
- Department of Liver Transplant, Sir Ganga Ram Hospital, New Delhi, India
| | - Ravi Mohanka
- Department of Liver Transplant, Sir Ganga Ram Hospital, New Delhi, India
| | - Neeraj Saraf
- Department of Liver Transplant, Sir Ganga Ram Hospital, New Delhi, India
| | - Amit Rastogi
- Department of Liver Transplant, Sir Ganga Ram Hospital, New Delhi, India
| | - Naimesh Mehta
- Department of Liver Transplant, Sir Ganga Ram Hospital, New Delhi, India
| | - Samiran Nundy
- Department of Liver Transplant, Sir Ganga Ram Hospital, New Delhi, India
| | - Arvinder Soin
- Department of Liver Transplant, Sir Ganga Ram Hospital, New Delhi, India
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Adams LA, Feldstein AE. Nonalcoholic steatohepatitis: risk factors and diagnosis. Expert Rev Gastroenterol Hepatol 2010; 4:623-35. [PMID: 20932147 DOI: 10.1586/egh.10.56] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Nonalcoholic steatohepatitis (NASH) represents the progressive form of nonalcoholic fatty liver disease with greater potential to lead to liver-related morbidity and mortality. Diagnosing NASH mandates more intensive clinical management and consideration for clinical trials. Currently, the diagnosis of NASH requires a liver biopsy, which is invasive, with drawbacks in sampling and interpretation error. Clinical risk factors for NASH include diabetes and the metabolic syndrome; however, these are not sufficiently predictive of the condition by themselves. Routine liver aminotransaminase levels are not reliable; however, novel plasma hepatocyte apoptosis markers, either alone or in combination with clinical risk factors, are potential noninvasive diagnostic tools for the future.
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Affiliation(s)
- Leon A Adams
- School of Medicine and Pharmacology, University of Western Australia, Sir Charles Gairdner Hospital Unit, Nedlands, WA 6009, Australia
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