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Abstract
PURPOSE OF REVIEW This article reviews the mechanisms leading to the development of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) and the effects of hypoglycaemic and lipid-lowering therapies on NAFLD/NASH. RECENT FINDINGS The interaction of lipogenesis, fatty acid oxidation, inflammation, endoplasmic reticulum stress and hepatic insulin resistance contribute to the pathogenesis of NAFLD/NASH. Few large scale clinical trials exist with biopsy or magnetic resonance endpoints as opposed to ultrasonographic and transaminase endpoints. Trial evidence that exists supports the utility of weight loss, metformin, thiazolidinediones, fibrates, niacin, ezetimibe and statins in improving the steatosis component of NAFLD/NASH though with less or minimal effects on the fibrotic component of NASH. SUMMARY Hypoglycaemic and lipid-lowering therapies may have a role in the treatment of NAFLD/NASH but large scale endpoint trials remain to be performed.
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Affiliation(s)
- Anthony S Wierzbicki
- Department of Metabolic Medicine/Chemical Pathologyemical Pathology, Guy's and St. Thomas' Hospitals, London, UK.
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202
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Wan H, Zhao Y, Wei X, Hui K, Giesy J, Wong CK. PFOS-induced hepatic steatosis, the mechanistic actions on β-oxidation and lipid transport. Biochim Biophys Acta Gen Subj 2012; 1820:1092-101. [DOI: 10.1016/j.bbagen.2012.03.010] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 03/15/2012] [Accepted: 03/16/2012] [Indexed: 02/06/2023]
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203
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The Current Knowledge of the Role of PPAR in Hepatic Ischemia-Reperfusion Injury. PPAR Res 2012; 2012:802384. [PMID: 22675337 PMCID: PMC3363006 DOI: 10.1155/2012/802384] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 03/16/2012] [Indexed: 12/15/2022] Open
Abstract
Strategies to improve the viability of steatotic livers could reduce the risk of dysfunction after surgery and increase the number of organs suitable for transplantation. Peroxisome proliferator-activated receptors (PPARs) are major regulators of lipid metabolism and inflammation. In this paper, we review the PPAR signaling pathways and present some of their lesser-known functions in liver regeneration. Potential therapies based on PPAR regulation will be discussed. The data suggest that further investigations are required to elucidate whether PPAR could be a potential therapeutic target in liver surgery and to determine the most effective therapies that selectively regulate PPAR with minor side effects.
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205
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Ramirez T, Tong M, Ayala CA, Monfils PR, McMillan PN, Zabala V, Wands JR, de la Monte SM. Structural Correlates of PPAR Agonist Rescue of Experimental Chronic Alcohol-Induced Steatohepatitis. ACTA ACUST UNITED AC 2012; 2. [PMID: 26339530 PMCID: PMC4554760 DOI: 10.4172/2161-0681.1000114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Chronic alcoholic liver disease is associated with hepatic insulin resistance, inflammation, oxidative and ER stress, mitochondrial dysfunction, and DNA damage. Peroxisome-proliferator activated receptor (PPAR) agonists are insulin sensitizers that have anti-inflammatory/anti-oxidant effects. We previously showed that PPAR agonists can restore hepatic insulin responsiveness in chronic ethanol-fed rats with steatohepatitis. Herein, we furthered our investigations by characterizing the histological and ultrastructural changes mediated by PPAR agonist rescue of alcohol-induced steatohepatitis. Adult male Long Evans rats were pair fed with isocaloric liquid diets containing 0% or 37% ethanol (caloric) for 8 weeks. After 3 weeks on the diets, rats were treated with vehicle, or a PPAR-α, PPAR-δ, or PPAR-γ agonist twice weekly by i.p. injection. Ethanol-fed rats developed steatohepatitis with disordered hepatic chord architecture, mega-mitochondria, disruption of the RER, increased apoptosis, and increased 4-hydroxynonenal (HNE) and 3-nitrotyrosine (NTyr) immunoreactivity. PPAR-δ and PPAR-γ agonists reduced the severity of steatohepatitis, and restored the hepatic chord-like architectural, mitochondrial morphology, and RER organization, and the PPAR-δ agonist significantly reduced hepatic HNE. On the other hand, prominent RER tubule dilation, which could reflect ER stress, persisted in ethanol-exposed, PPAR-γ treated but not PPAR-δ treated livers. The PPAR-α agonist exacerbated both steatohepatitis and formation of mega-mitochondria, and it failed to restore RER architecture or lower biochemical indices of oxidative stress. In conclusion, improved hepatic insulin responsiveness and decreased inflammation resulting from PPAR-δ or PPAR-γ agonist treatments of alcohol-induced steatohepatitis are likely mediated by enhanced signaling through metabolic pathways with attendant reductions in ER stress, oxidative stress, and mitochondrial dysfunction.
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Affiliation(s)
- Teresa Ramirez
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Ming Tong
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Carol A Ayala
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Paul R Monfils
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Paul N McMillan
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Valerie Zabala
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Jack R Wands
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Suzanne M de la Monte
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
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