Increased Liver Fatty Acid Uptake Is Partly Reversed and Liver Fat Content Normalized After Bariatric Surgery

“…For this study, we aimed to assess the effects of bariatric surgery on NEFA uptake, on triglyceride content and on the proportion of brown fat in the supraclavicular fat depot of morbidly obese patients. Abdominal adipose tissue, pancreas and liver NEFA uptake rates concerning the same study patients have been published previously.…”

Section: Introductionmentioning

confidence: 98%

Brown adipose tissue lipid metabolism in morbid obesity: Effect of bariatric surgery‐induced weight loss

Dadson

Hannukainen

U-Din

et al. 2018

Diabetes Obesity Metabolism

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“…Although often suggested to be the major contributor to liver TAG, Donnelly et al (8) using stable-isotope tracer methodology, reported that plasma NEFA contributed between 45 and 74 % to liver TAG (after a 4 d stable-isotope labelling procedure); thus it is plausible that some, but not all, individuals develop NAFLD due to an increased fatty acid flux from adipose tissue to the liver. Positron emission tomography/computed tomography in combination with labelled palmitate ( 11 C) or a palmitate analogue fluoro-6-thia-heptadecanoic acid have been used to assess hepatic fatty acid uptake (17,18) . It was found that hepatic fatty acid uptake was higher, although not significantly different, in obese compared with overweight control subjects (17) whilst in morbidly obese individuals hepatic fatty acid uptake is significantly higher before and 6 months after bariatric surgery than in lean controls, despite liver fat content being normalised (18) .…”

Section: Fatty Acid Sources: Adipose Tissuementioning

confidence: 99%

Hepatic fatty acid synthesis and partitioning: the effect of metabolic and nutritional state

Hodson

2018

Proc. Nutr. Soc.

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When we consume dietary fat, a series of complex metabolic processes ensures that fatty acids are absorbed, transported around the body and used/stored appropriately. The liver is a central metabolic organ within the human body and has a major role in regulating fat and carbohydrate metabolism. Studying hepatic metabolism in human subjects is challenging; the use of stable isotope tracers and measurement of particles or molecules secreted by the liver such as VLDL-TAG and 3-hydroxybutyrate offers the best insight into postprandial hepatic fatty acid metabolism in human subjects. Diet derived fatty acids are taken up by the liver and mix with fatty acids coming from the lipolysis of adipose tissue, and those already present in the liver (cytosolic TAG) and fatty acids synthesised de novo within the liver from non-lipid precursors (known as de novo lipogenesis). Fatty acids are removed from the liver by secretion as VLDL-TAG and oxidation. Perturbations in these processes have the potential to impact on metabolic health. Whether fatty acids are partitioned towards oxidation or esterification pathways appears to be dependent on a number of metabolic factors; not least ambient insulin concentrations. Moreover, along with the phenotype and lifestyle factors (e.g. habitual diet) of an individual, it is becoming apparent that the composition of the diet (macronutrient and fatty acid composition) may play pivotal roles in determining if intra-hepatic fat accumulates, although what remains to be elucidated is the influence these nutrients have on intra-hepatic fatty acid synthesis and partitioning. Liver: VLDL-TAG: Fatty acid partitioning: Fatty acid oxidationThe liver has a major role in regulating metabolic homeostasis; it is a central cross-road for fatty acid and glucose metabolism. It serves as an intermediary organ between dietary (exogenous) and endogenous energy sources and other extra-hepatic organs/tissues that consume energy; perturbations in its metabolism have the potential to impact widely on metabolic disease risk. In health, the liver rapidly adapts to alterations in nutritional state and the nutrient fluxes that occur from a fasted (postabsorptive) to fed (postprandial) state. However, the deposition of fat (ectopic fat) in nonadipose tissues such as the liver has been suggested to be an important factor in the development of obesity related metabolic abnormalities (1,2) . The net retention of intra-hepatic fat is a prerequisite for the development of non-alcoholic fatty liver disease (NAFLD) (3) , which is now recognised as the hepatic manifestation of the metabolic syndrome (2) . A well-recognised risk factor for NAFLD is obesity, and both are risk factors for more severe metabolic diseases such as type-2 diabetes and CVD; the prevalence of NAFLD parallels that of type-2 diabetes (4) . Why the liver starts to accumulate fat is not well understood but is likely to occur when fatty acid input and synthesis exceed the liver's capacity for removal (e.g. for secretion or oxidation) (5)(6)(7) . The intra-hepa...

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“…In a recent study in morbidly obese subjects, Immonen and coworkers, using a palmitate analog, [ 18 F]-fluoro-6-thiaheptadecanoic acid ( 18 F-FTHA), found morbidly obese subjects to have elevated hepatic fatty acid uptake (HFU) before bariatric surgery that decreased after surgery, though it did not normalize relative to lean subjects. Intriguingly, HFU and liver fat content in these patients were not related[ 78 ]. Iozzo et al[ 79 ] using 11 C-palmitate-PET scanning showed that obese subjects have higher rate of fatty acid oxidation than lean subjects.…”

Section: Pet To Study Liver Metabolismmentioning

confidence: 99%

“…According to these authors, the assessment of fatty acid oxidation is of major importance in characterizing subjects with NAFLD, since fatty acid oxidation is a significant source of reactive oxygen species in obesity-related hepatic lipotoxicity. Finally, with appropriate modeling, PET like MRI can be used in the quantification of liver perfusion in humans[ 78 , 80 ].…”

Section: Pet To Study Liver Metabolismmentioning

confidence: 99%

Digital liver biopsy: Bio-imaging of fatty liver for translational and clinical research

Mancini¹,

Summers²,

Faita³

et al. 2018

WJH

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The rapidly growing field of functional, molecular and structural bio-imaging is providing an extraordinary new opportunity to overcome the limits of invasive liver biopsy and introduce a “digital biopsy” for in vivo study of liver pathophysiology. To foster the application of bio-imaging in clinical and translational research, there is a need to standardize the methods of both acquisition and the storage of the bio-images of the liver. It can be hoped that the combination of digital, liquid and histologic liver biopsies will provide an innovative synergistic tri-dimensional approach to identifying new aetiologies, diagnostic and prognostic biomarkers and therapeutic targets for the optimization of personalized therapy of liver diseases and liver cancer. A group of experts of different disciplines (Special Interest Group for Personalized Hepatology of the Italian Association for the Study of the Liver, Institute for Biostructures and Bio-imaging of the National Research Council and Bio-banking and Biomolecular Resources Research Infrastructure) discussed criteria, methods and guidelines for facilitating the requisite application of data collection. This manuscript provides a multi-Author review of the issue with special focus on fatty liver.

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Increased Liver Fatty Acid Uptake Is Partly Reversed and Liver Fat Content Normalized After Bariatric Surgery

Abstract: The findings suggest that in a postoperative state, intrahepatic fatty acids are not stored in the liver but are used for oxidation to provide energy. Changes in perfusion may contribute to improved liver metabolism postoperatively.

Cited by 24 publications

References 12 publications

Brown adipose tissue lipid metabolism in morbid obesity: Effect of bariatric surgery‐induced weight loss

Brown adipose tissue lipid metabolism in morbid obesity: Effect of bariatric surgery‐induced weight loss

Hepatic fatty acid synthesis and partitioning: the effect of metabolic and nutritional state

Digital liver biopsy: Bio-imaging of fatty liver for translational and clinical research

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