Free Fatty Acid Β-oxidation Research Articles

Do low skeletal muscle bulk and disturbed body fat mass impact tumor recurrence in stage I/II HCC undergoing surgery? An observational cohort study.

The influence of deranged body composition on stage I/II HCC after surgery remains undetermined. The current study aimed to investigate the impact of low skeletal muscle bulk and disturbed body fat mass on the recurrence outcome of stage I/II HCC patients undergoing liver resection. The associated metabolomic alterations were also assessed. From 2012 to 2021, stage I and II HCC patients who underwent liver resection at our institute were retrospectively reviewed. Their preoperative body composition including skeletal muscle mass and body fat volume was measured by computed tomography (CT). The recurrence outcome was recorded and analyzed. The preoperative serum was collected and subjected to metabolomic analysis. A total of 450 stage I and II HCC patients were included in the current study. Among them, 76% were male and around 60% had HBV infection. After stratified by normal cutoff values obtained from a healthy cohort, 6.4% of stage I/II HCC patients were found to have a low psoas muscle index (PMI), 17.8% a high subcutaneous adipose tissue (SAT) index, and 27.8% a high visceral adipose tissue (VAT) index. Cox regression multivariate analysis further demonstrated that low PMI and high SAT index were independent prognostic factors for time-to-recurrence (TTR) after surgery. Metabolomic analysis discovered that free fatty acid β-oxidation was enhanced in with low PMI or high SAT index. The current study demonstrated that reduced psoas muscle mass may impair while elevated SAT may prolong the TTR of stage I/II HCC patients undergoing liver resections. VAT, on the other hand, was not associated with recurrence outcome after surgery. Further studies are warranted to validate our findings.

Mitochondrial Proteins as Metabolic Biomarkers and Sites for Therapeutic Intervention in Primary and Metastatic Cancers.

Accelerated aerobic glycolysis is one of the main metabolic alterations in cancer, associated with malignancy and tumor growth. Although glycolysis is one of the most studied properties of tumor cells, recent studies demonstrate that oxidative phosphorylation (OxPhos) is the main ATP provider for the growth and development of cancer. In this last regard, the levels of mRNA and protein of OxPhos enzymes and transporters (including glutaminolysis, acetate and ketone bodies catabolism, free fatty acid β-oxidation, Krebs Cycle, respiratory chain, phosphorylating system- ATP synthase, ATP/ADP translocator, Pi carrier) are altered in tumors and cancer cells in comparison to healthy tissues and organs, and non-cancer cells. Both energy metabolism pathways are tightly regulated by transcriptional factors, oncogenes, and tumor-suppressor genes, all of which dictate their protein levels depending on the micro-environmental conditions and the type of cancer cell, favoring cancer cell adaptation and growth. In the present review paper, variation in the mRNA and protein levels as well as in the enzyme/ transporter activities of the OxPhos machinery is analyzed. An integral omics approach to mitochondrial energy metabolism pathways may allow for identifying their use as suitable, reliable biomarkers for early detection of cancer development and metastasis, and for envisioned novel, alternative therapies.

Role of gut-liver axis and glucagon-like peptide-1 receptor agonists in the treatment of metabolic dysfunction-associated fatty liver disease.

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a hepatic manifestation of the metabolic syndrome. It is one of the most common liver diseases worldwide and shows increasing prevalence rates in most countries. MAFLD is a progressive disease with the most severe cases presenting as advanced fibrosis or cirrhosis with an increased risk of hepatocellular carcinoma. Gut microbiota play a significant role in the pathogenesis and progression of MAFLD by disrupting the gut-liver axis. The mechanisms involved in maintaining gut-liver axis homeostasis are complex. One critical aspect involves preserving an appropriate intestinal barrier permeability and levels of intestinal lumen metabolites to ensure gut-liver axis functionality. An increase in intestinal barrier permeability induces metabolic endotoxemia that leads to steatohepatitis. Moreover, alterations in the absorption of various metabolites can affect liver metabolism and induce liver steatosis and fibrosis. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are a class of drugs developed for the treatment of type 2 diabetes mellitus. They are also commonly used to combat obesity and have been proven to be effective in reversing hepatic steatosis. The mechanisms reported to be involved in this effect include an improved regulation of glycemia, reduced lipid synthesis, β-oxidation of free fatty acids, and induction of autophagy in hepatic cells. Recently, multiple peptide receptor agonists have been introduced and are expected to increase the effectiveness of the treatment. A modulation of gut microbiota has also been observed with the use of these drugs that may contribute to the amelioration of MAFLD. This review presents the current understanding of the role of the gut-liver axis in the development of MAFLD and use of members of the GLP-1 RA family as pleiotropic agents in the treatment of MAFLD.

Effects of (-)-epicatechin on hepatic triglyceride metabolism.

(-)-Epicatechin (EC) consumption is associated with an improvement of hyperlipemia and other metabolic changes linked to obesity and western-style diets. This work investigated the effects of EC on triglyceride (TG) metabolism both in vivo, where mice were supplemented with EC (2 and 20 mg EC per kg body weight), and in vitro, when human HepG2 hepatocytes were incubated in the presence of EC and the main EC metabolites found in human plasma. Increased hepatic TG levels were only observed after 24 weeks supplementation with EC (20 mg per kg body weight), with a preserved liver structure and absence of inflammation or oxidative stress. EC caused increased expression of diacylglycerol acyltransferases (DGAT2), key enzymes in TG synthesis, and the upregulation of PPARα, which promotes free fatty acid (FFA) oxidation. On the other hand, incubation of HepG2 cells in the presence of high concentrations of EC (1-10 μM) did not affect TG deposition nor DGAT2 expression. In summary, in mouse liver, EC upregulated mechanisms that can neutralize the potential toxicity of FFA, i.e. TG synthesis and FFA β-oxidation. Results in mouse liver and HepG2 cells stress the safety of EC in terms of TG metabolism and development of hepatopathies in doses within the limits given by a rational time and dose for human consumption.

Alginate oligosaccharides improve high-fat induced hepatic steatosis via PGC-1α-mediated lipophagy and fatty acid β-oxidation pathway

This study explored the lipid-lowering effect and intervention mechanism of alginate oligosaccharides (AOS) on non-alcoholic fatty liver disease (NAFLD). Results showed that both unsaturated (UAOS) and saturated (SAOS) AOS improved the hepatic steatosis of NAFLD mice fed a high-fat diet (HFD). AOS promoted lipid catabolism in vivo and in vitro by activating the lipophagy and free fatty acid (FFA) β-oxidation pathways. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) represented the up-stream target of the FFA β-oxidation pathway and upregulated both in in vivo and in vitro, suggesting it might be the AOS intervention target. By activating or inhibiting PGC-1α, AOS modulated the PGC-1α activity to reduce hepatic lipid accumulation. Therefore, the results indicated that AOS exhibited a lipid-lowering effect via the PGC-1α-mediated lipophagy-FFA β-oxidation transduction signal axis. These findings provided insight into using food-derived ingredients to intervene and treat chronic diseases involving lipid metabolism disorders.

CD36 inhibition partially attenuates myocardial injury in diabetic rats with ischemic postconditioning

IntroductionTo investigate the role of CD36 (fatty acid translocation enzyme) in the myocardial ischemia reperfusion (IR) injury in diabetes with ischemic postconditioning (IPostC).Research design and methodsAdult male Sprague-Dawley rats received...

Mitochondria Matter: Systemic Aspects of Nonalcoholic Fatty Liver Disease (NAFLD) and Diagnostic Assessment of Liver Function by Stable Isotope Dynamic Breath Tests.

The liver plays a key role in systemic metabolic processes, which include detoxification, synthesis, storage, and export of carbohydrates, lipids, and proteins. The raising trends of obesity and metabolic disorders worldwide is often associated with the nonalcoholic fatty liver disease (NAFLD), which has become the most frequent type of chronic liver disorder with risk of progression to cirrhosis and hepatocellular carcinoma. Liver mitochondria play a key role in degrading the pathways of carbohydrates, proteins, lipids, and xenobiotics, and to provide energy for the body cells. The morphological and functional integrity of mitochondria guarantee the proper functioning of β-oxidation of free fatty acids and of the tricarboxylic acid cycle. Evaluation of the liver in clinical medicine needs to be accurate in NAFLD patients and includes history, physical exam, imaging, and laboratory assays. Evaluation of mitochondrial function in chronic liver disease and NAFLD is now possible by novel diagnostic tools. “Dynamic” liver function tests include the breath test (BT) based on the use of substrates marked with the non-radioactive, naturally occurring stable isotope 13C. Hepatocellular metabolization of the substrate will generate 13CO2, which is excreted in breath and measured by mass spectrometry or infrared spectroscopy. Breath levels of 13CO2 are biomarkers of specific metabolic processes occurring in the hepatocyte cytosol, microsomes, and mitochondria. 13C-BTs explore distinct chronic liver diseases including simple liver steatosis, non-alcoholic steatohepatitis, liver fibrosis, cirrhosis, hepatocellular carcinoma, drug, and alcohol effects. In NAFLD, 13C-BT use substrates such as α-ketoisocaproic acid, methionine, and octanoic acid to assess mitochondrial oxidation capacity which can be impaired at an early stage of disease. 13C-BTs represent an indirect, cost-effective, and easy method to evaluate dynamic liver function. Further applications are expected in clinical medicine. In this review, we discuss the involvement of liver mitochondria in the progression of NAFLD, together with the role of 13C-BT in assessing mitochondrial function and its potential use in the prevention and management of NAFLD.

440-P: Dual Long-Term Effects of Free Fatty Acid on Human Endothelial Barrier In Vitro Are Mediated by NO, Mitochondrial ROS, and Dicarbonyl Stress

In diabetes-associated hyperlipidemia, free fatty acids (FFAs) are thought to induce insulin resistance and endothelial dysfunction leading to vascular injury and cardiovascular T2DM complications. However, evidence is scarce regarding the effects of FFA on vascular endothelial barrier. We used human umbilical vein endothelial cells (HUVEC) to model, in vitro, the endothelial barrier and reveal its responses to experimental hyperlipidemia induced by long-term treatment with palmitic acid in complex with albumin. Palmitate was continuously present in the growth medium at 0.8 mM to reproduce FFA levels typical for T2DM. We developed conditions to maintain the HUVEC monolayers in the presence of the high palmitate concentration for up to 2 weeks by adding exogenous carnitine to facilitate mitochondrial β-oxidation of FFA. In this model system, palmitate readily augmented the transendothelial electric resistance (TER) of HUVEC via increased NO production by endothelial NO-synthase (eNOS). Western blots showed that palmitate neither disturbed insulin signaling cascade towards eNOS nor upregulated eNOS expression. After the initial 3-4-day rise in TER, further treatment with palmitate led to barrier stabilization and attenuation as compared to FFA-free conditions. This later phase was associated with increased ROS and malondialdehyde (MDA) accumulation, both prevented by the mitochondria-targeted antioxidant SkQ1. Treatment of HUVEC with exogenous MDA impaired the TER and barrier suggesting that accumulation of MDA-modified proteins may contribute to the barrier dysfunction upon long-term experimental hyperlipidemia. Altogether, obtained evidence suggests that prolonged exposure of vascular endothelium to high levels of palmitate compromises endothelium barrier capacity and insulin-mediated eNOS regulation turning the enzyme permanently active. Disclosure M. Samsonov: None. V. P. Shirinsky: None. N. Podkuychenko: None. A. Y. Khapchaev: None. T. Vlasik: None. V. Lankin: None. M. Skulachev: Other Relationship; Self; Mitotech LLC. I. Stafeev: None. A. V. Vorotnikov: None. M. V. Shestakova: None. Funding Russian Science Foundation (19-15-00361)

Nonalcoholic Fatty Liver Disease (NAFLD). Mitochondria as Players and Targets of Therapies?

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and represents the hepatic expression of several metabolic abnormalities of high epidemiologic relevance. Fat accumulation in the hepatocytes results in cellular fragility and risk of progression toward necroinflammation, i.e., nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Several pathways contribute to fat accumulation and damage in the liver and can also involve the mitochondria, whose functional integrity is essential to maintain liver bioenergetics. In NAFLD/NASH, both structural and functional mitochondrial abnormalities occur and can involve mitochondrial electron transport chain, decreased mitochondrial β-oxidation of free fatty acids, excessive generation of reactive oxygen species, and lipid peroxidation. NASH is a major target of therapy, but there is no established single or combined treatment so far. Notably, translational and clinical studies point to mitochondria as future therapeutic targets in NAFLD since the prevention of mitochondrial damage could improve liver bioenergetics.

Slow-Release H2S Donor Anethole Dithiolethione Protects Liver From Lipotoxicity by Improving Fatty Acid Metabolism.

“Lipotoxicity” induced by free fatty acids (FAs) plays a central role in the pathogenesis of many metabolic diseases, with few treatment options available today. Hydrogen sulfide (H2S), a novel gaseous signaling molecule, has been reported to have a variety of pharmacological properties, but its effect on FAs metabolism remains unclear. The purpose of this study was to investigate the effect and mechanisms of anethole dithiolethione (ADT, a sustained-release H2S donor) on hepatic FAs metabolism. ADT was administered daily for 4 weeks in male Syrian golden hamsters fed a high fat diet (HFD), and FAs profiles of liver tissues were analyzed using GC-MS. The results showed that in HFD-fed hamsters, ADT treatment significantly reduced the accumulation of toxic saturated and monounsaturated fatty acids (C16:0, C18:0, C16:1, and C18:1n9), while increased the content of n-6 and n-3 series polyunsaturated fatty acids (C20:3n6, C20:4n6, and C22:6n3). Mechanistically, ADT obviously inhibited the overexpression of acetyl-CoA carboxylase1 (ACC1), fatty acid synthase (FAS), and stearoyl-CoA desaturase1 (SCD1), and up-regulated the levels of fatty acid transport proteins (FATPs), liver fatty acid binding protein (L-FABP), carnitine palmitoyltransferase 1α (CPT1α), fatty acid desaturase (FADS)1 and FADS2. Notably, ADT administration significantly promoted Mitofusin1-mediated mitochondrial fusion and fatty acid β-oxidation. These findings suggest that ADT plays a beneficial role by regulating the synthesis, desaturation, β-oxidation, uptake, binding/isolation, and transport of FAs. In conclusion, ADT is effective in improving FAs metabolic disorders and liver injuries caused by HFD, which renders ADT a candidate drug for lipotoxicity-induced diseases.

Crocetin Attenuates Sepsis-Induced Cardiac Dysfunction via Regulation of Inflammatory Response and Mitochondrial Function.

Sepsis-induced systemic inflammation can induce cardiac dysfunction, which can result in heart failure and death. Recently, natural drugs/compounds have received increased attention as therapeutic agents to prevent sepsis-induced cardiac dysfunction. Crocetin (CRO) is a natural compound that has been shown to reduce inflammation and cytotoxicity in cardiac ischemia/reperfusion injury. However, the effects of CRO on sepsis-induced cardiac dysfunction have not been evaluated. In this study, we used lipopolysaccharide (LPS)-induced H9c2 cells as an in vitro model to mimic cardiac sepsis. Crocetin significantly alleviated LPS-induced cytotoxicity, cellular apoptosis, and oxidative stress through increased Bcl-2 activity and PI3K-Akt signaling and suppression of caspase 3 and caspase 9 activities. Furthermore, CRO dramatically decreased the mRNA levels of TNF-α, IL-1, IL-6, and IL-8 via suppression of p65/Keap1 signaling and activation of Nrf2/HO-1/NQO1 signaling. In addition, CRO protected mitochondrial respiration, free fatty acid β-oxidation, and mitochondrial morphology in LPS-induced H9c2 cells. This study showed that CRO attenuated LPS-induced cardiac dysfunction via regulation of the inflammatory response and mitochondrial function and potentially had an effect on sepsis-induced cardiac dysfunction.

128-LB: Effects of Glucagon Receptor Antagonism (GRA) on Ketone Body Formation during Insulinopenia in Type 1 Diabetes (T1D)

Background: Diabetic ketoacidosis is a common and life-threatening complication of T1D. Glucagon stimulates ketogenesis via peripheral lipolysis and hepatic β-oxidation of free fatty acids (FFA). Blocking glucagon action may decrease ketone formation and reduce the risk of DKA. Methods: In this pilot study, 4 participants with T1D underwent 6 hours of insulin withdrawal before and after 4 weeks of monoclonal GRA treatment (REMD-477, 70mg weekly). Serial measurements of plasma glucose, FFA, and β-hydroxybutyrate (BHB) were collected to determine the efficacy of GRA therapy in reducing ketone formation in the setting of insulinopenia. Results: Pre- vs. post-treatment concentrations (mean ± SD; paired two-tailed t-test) after 6-hour insulin withdrawal were: Glucose (263 ± 63 vs. 235 ± 109 mg/dL; P = 0.53), FFA (1.37 ± 0.60 vs. 1.09 ± 0.77 mmol/L; P = 0.07), and BHB (1.30 ± 0.70 vs. 0.63 ± 0.54 mmol/L; P = 0.08). Glucagon concentrations increased (26.8 ± 9.9 vs. 454 ± 245 pg/mL; P = 0.04) with blockade of glucagon action. Frequent insulin draws confirmed insulinopenia. Conclusions: These preliminary results suggest that GRA treatment may reduce ketogenesis in the clinical setting in which DKA occurs (insulinopenia). These trends will be tested in a larger, randomized study. If confirmed, this would represent a novel therapy to reduce the risk of life-threatening DKA in T1D. Disclosure S.C. Boeder: Consultant; Self; Cecelia Health, Science 37. Research Support; Self; Dexcom, Inc. D.G. Ines: None. L. Carter: None. E.R. Giovannetti: None. D. Armstrong: None. P. Burke: None. J. Pettus: Consultant; Self; Diasome Pharmaceuticals, Inc., Lexicon Pharmaceuticals, Inc., MannKind Corporation, Novo Nordisk Inc., Sanofi. Funding National Institutes of Health (UL1TR001442, P30DK063491)

Novel defatting strategies reduce lipid accumulation in primary human culture models of liver steatosis.

ABSTRACTNormothermic perfusion provides a means to rescue steatotic liver grafts, including by pharmacological defatting. In this study, we tested the potential of new drug combinations to trigger defatting in three human culture models, primary hepatocytes with induced steatosis, primary hepatocytes isolated from steatotic liver, and precision-cut liver slices (PCLS) of steatotic liver. Forskolin, L-carnitine and a PPARα agonist were all combined with rapamycin, an immunosuppressant that induces autophagy, in a D-FAT cocktail. D-FAT was tested alone or in combination with necrosulfonamide, an inhibitor of mixed lineage kinase domain like pseudokinase involved in necroptosis. Within 24 h, in all three models, D-FAT induced a decrease in triglyceride content by 30%, attributable to an upregulation of genes involved in free fatty acid β-oxidation and autophagy, and a downregulation of those involved in lipogenesis. Defatting was accompanied by a decrease in endoplasmic reticulum stress and in the production of reactive oxygen species. The addition of necrosulfonamide increased the efficacy of defatting by 8%-12% in PCLS, with a trend towards increased autophagy. In conclusion, culture models, notably PCLS, are insightful to design strategies for liver graft rescue. Defatting can be rapidly achieved by combinations of drugs targeting mitochondrial oxidative metabolism, macro-autophagy and lipogenesis.

Effect of nutrients and exhaustive exercise on brain function.

Epidemiological evidence suggests that health-oriented eating habits are associated with maintaining optimal cognitive ability. Nutrients are functional bioactive molecules promoting human health and essential components as well. Docosahexaenoic acid (DHA; 22:6n-3), one of polyunsaturated fatty acids (PUFAs) is synthesized through elongation pathway from linolenic acid (81:3n-3) which is recognized as important source of brain function. Endurance physical exercise and energy restriction was also recognized of cardiovascular stress adjustment by enhancing brainstem cholinergic activity as well as brain function. However, we even do not know the exact neuronal mechanisms about the nutrients, β-hydroxybutyrate (β-HB) and myokine impacts on brain-derived neurotropic factor (BDNF) activation. Therefore, this review focuses on recent evidence that explains how nutrients and prolonged exercise can affect nervous system pathways that are associated with improving brain function. The results revealed that frequent consumption of polyphenols and n-3 PUFAs could modify gastrointestinal environment with beneficial microorganisms. It may suggest a new hypothesis that gastrointestinal microbiome could influence cognitive function in addition to the traditional etiological pathway. And moreover, prolonged physical exercise includes open skill sports which is induced by β-oxidation of free fatty acids stimulate BDNF. And also β-HB production which is induced by carbohydrate depletion, hypoglycemia, or fasting stimulate BDNF production that acts an significantly important roles in cognitive function and acting on brain function with brain metabolism.

Lactate in cardiogenic shock - current understanding and clinical implications.

Adenosine triphosphate (ATP) is an essential substrate metabolite in human beings. Mitochondrial oxidative phosphorylation provides > 95% of ATP with the remainder derived from glycolysis or tricarboxylic acid cycle (TCA). In normal hearts, acetyl-CoA is synthesized from the β-oxidation of free fatty acids (FFA) and the oxidation of pyruvate. Pyruvate is synthesized from glycolysis and can be submitted either for decarboxylation to acetyl-CoA or for dehydrogenation to lactate. Moreover, pyruvate, as well as lactate, plays a key role in aerobic glucose metabolism which is highly dependent on ubiquitous regulatory mechanisms. Many recent advances in molecular biology, genetics, and physiology have revealed new insights into the metabolic flux of lactate. The initial perception characterized by increased lactate production and accumulation in peripheral tissues in anaerobic conditions has been recently contested. The paradigm of increased lactate concentration in the anaerobic setting is discussed according to contemporary reports. Nevertheless, the clinical role of lactate as a prognostic factor in cardiovascular diseases is undisturbed, especially in the field of innovative technology of left/bi ventricular-assist devices and biochips where it reassured its diagnostic and prognostic impact on the cardiovascular system.

Tributyrin Administration Targets Alcohol‐induced Pathogenic Mechanisms in the Gut‐liver Axis: Relevance to the Development of Therapeutic Strategies in Alcoholic Liver Disease

IntroductionEmerging evidence has established the important role of the “gut‐liver” axis in the development of alcoholic liver disease (ALD). Alcohol‐induced enteric dysbiosis plays an essential role in the pathogenesis of alcoholic liver disease on the gut liver axis. Tributyrin (Tb) is a triglyceride that is rapidly absorbed and metabolized to butyrate by pancreatic lipases. Butyrate is the primary fuel source for colonocytes and improves gut barrier function. Moreover, butyrate is a known HDAC inhibitor.ObjectiveTributyrin modulates alcohol‐induced gut microbiome and barrier function and prevents hepatic steatosis via HDAC inhibition at CPT‐1 promoterMethodsMice were fed liquid Lieber‐DeCarli diet without or with alcohol (5% v/v) for a duration 7 weeks. A subset of mice were administered tributyrin (orally gavaged). Metagenomic analysis of the gut microbiome was performed by analyzing the fecal DNA by amplification of the V3–V5 regions of the 16S rRNA gene and large‐scale parallel sequencing on the Illumina MiSeq platform. Primary rat hepatocytes were exposed to alcohol (50 mM) with/without butyrate pre‐treatment for 24 hrs. Isolation of RNA was carried out using Trizol. Chromatin immunoprecipitation (ChIP) analysis was performed to examine the epigenetic modifications occurring in response to alcohol and butyrate at CPT‐1 promoter.ResultsEffect of tributyrin on alcohol‐induced intestinal dysbiosis and hepatic injury was evaluated. Tributyrin co‐administration prevented chronic alcohol‐induced i) microbial dysbiosis as documented by decrease in the diversity of the gut microbiome, ii) increase in systemic endotoxemia iii) hepatic steatosis and injury. Additionally, pharmacokinetic studies showed increase in plasma butyrate concentration in the hepato‐portal vein after tributyrin gavage. Notably, tributyrin prevented the ethanol‐induced down‐regulation of hepatic CPT‐1, a key enzyme in free fatty acid β‐oxidation. Specifically the effect of butyrate as HDAC inhibitor was evaluated in primary rat hepatocytes by examining CPT‐1 promoter region. Hepatocytes exposed to alcohol showed an increase in HDAC1 recruitment at the CPT‐1 promoter, which was prevented by butyrate. Correspondently, butyrate led to an increase in p300 recruitment with a subsequent increase in transcriptionally permissive histone acetylation at the proximal region of CPT‐1 promoter. This butyrate induced open chromatin configuration further allowed recruitment of RNA‐Pol II leading to CPT‐1 transcription.ConclusionsIn conclusion, tributyrin administration increases the diversity of the bacterial communities and prevents alcohol induced gut dysbiosis. Moreover, Tb attenuates hepatic steatosis by affecting alcohol‐induced, HDAC‐mediated epigenetic mechanisms the down regulate CPT‐1 gene expression. Taken together, these data also support that Tb supplementation is a potential therapeutic strategy in the treatment of ALD.Support or Funding InformationThis work is supported by NIH/NIAAA grants.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Modulating the metabolism by trimetazidine enhances myoblast differentiation and promotes myogenesis in cachectic tumor-bearing c26 mice.

Trimetazidine (TMZ) is a metabolic reprogramming agent able to partially inhibit mitochondrial free fatty acid β-oxidation while enhancing glucose oxidation. Here we have found that the metabolic shift driven by TMZ enhances the myogenic potential of skeletal muscle progenitor cells leading to MyoD, Myogenin, Desmin and the slow isoforms of troponin C and I over-expression. Moreover, similarly to exercise, TMZ stimulates the phosphorylation of the AMP-activated protein kinase (AMPK) and up-regulates the peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC1α), both of which are known to enhance the mitochondrial biogenesis necessary for myoblast differentiation. TMZ also induces autophagy which is required during myoblast differentiation and promotes myoblast alignment which allows cell fusion and myofiber formation. Finally, we found that intraperitoneally administered TMZ (5mg/kg) is able to stimulate myogenesis in vivo both in a mice model of cancer cachexia (C26 mice) and upon cardiotoxin damage. Collectively, our work demonstrates that TMZ enhances myoblast differentiation and promotes myogenesis, which might contribute recovering stem cell blunted regenerative capacity and counteracting muscle wasting, thanks to the formation of new myofibers; TMZ is already in use in humans as an anti-anginal drug and its repositioning might impact significantly on aging and regeneration-impaired disorders, including cancer cachexia, as well as have implications in regenerative medicine.

Identification of Estrogen-Related Receptor α Agonists in the Tox21 Compound Library.

The estrogen-related receptor α (ERRα) is an orphan nuclear receptor (NR) that plays a role in energy homeostasis and controls mitochondrial oxidative respiration. Increased expression of ERRα in certain ovarian, breast, and colon cancers has a negative prognosis, indicating an important role for ERRα in cancer progression. An interaction between ERRα and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) has also recently been shown to regulate an enzyme in the β-oxidation of free fatty acids, thereby suggesting that ERRα plays an important role in obesity and type 2 diabetes. Therefore, it would be prudent to identify compounds that can act as activators of ERRα. In this study, we screened ∼10,000 (8311 unique) compounds, known as the Tox21 10K collection, to identify agonists of ERRα. We performed this screen using two stably transfected HEK 293 cell lines, one with the ERRα-reporter alone and the other with both ERRα-reporter and PGC-1α expression vectors. After the primary screening, we identified more than five agonist clusters based on compound structural similarity analysis (e.g., statins). By examining the activities of the confirmed ERRα modulators in other Tox21 NR assays, eliminating those with promiscuous NR activity, and performing follow-up assays (e.g., small interfering RNA knockdown), we identified compounds that might act as endocrine disrupters through effects on ERRα signaling. To our knowledge, this study is the first comprehensive analysis in discovering potential endocrine disrupters that affect the ERRα signaling pathway.

Impaired β-Oxidation and Altered Complex Lipid Fatty Acid Partitioning with Advancing CKD.

Studies of lipids in CKD, including ESRD, have been limited to measures of conventional lipid profiles. We aimed to systematically identify 17 different lipid classes and associate the abundance thereof with alterations in acylcarnitines, a metric of β-oxidation, across stages of CKD. From the Clinical Phenotyping Resource and Biobank Core (CPROBE) cohort of 1235 adults, we selected a panel of 214 participants: 36 with stage 1 or 2 CKD, 99 with stage 3 CKD, 61 with stage 4 CKD, and 18 with stage 5 CKD. Among participants, 110 were men (51.4%), 64 were black (29.9%), and 150 were white (70.1%), and the mean (SD) age was 60 (16) years old. We measured plasma lipids and acylcarnitines using liquid chromatography-mass spectrometry. Overall, we identified 330 different lipids across 17 different classes. Compared with earlier stages, stage 5 CKD associated with a higher abundance of saturated C16-C20 free fatty acids (FFAs) and long polyunsaturated complex lipids. Long-chain-to-intermediate-chain acylcarnitine ratio, a marker of efficiency of β-oxidation, exhibited a graded decrease from stage 2 to 5 CKD (P<0.001). Additionally, multiple linear regression revealed that the long-chain-to-intermediate-chain acylcarnitine ratio inversely associated with polyunsaturated long complex lipid subclasses and the C16-C20 FFAs but directly associated with short complex lipids with fewer double bonds. We conclude that increased abundance of saturated C16-C20 FFAs coupled with impaired β-oxidation of FFAs and inverse partitioning into complex lipids may be mechanisms underpinning lipid metabolism changes that typify advancing CKD.

Resveratrol improves high-fat diet induced fatty liver and insulin resistance by concomitantly inhibiting proteolytic cleavage of sterol regulatory element-binding proteins, free fatty acid oxidation, and intestinal triglyceride absorption

Resveratrol (RES) has the ability to ameliorate nonalcoholic fatty liver disease (NAFLD) and the mechanism remains unclear. Hence, using high-fat diet (HFD) obese rat model, we investigated the effect of a low dose of RES (20 mg/kg) on the hepatic sterol regulatory element-binding protein (SREBPs) - lipogenesis pathway, enzymes involved in β-oxidation and activity of pancreatic lipase. Four groups of rats (n = 8) of control (12% of calories as fat) and HFD (40% of calories as fat) were administered orally with either normal saline as a vehicle or RES as a concomitant treatment for 8 weeks on a daily basis. Then, various biochemical, histological, and molecular experiments were carried out. RES prevented the development and progression of NAFLD and significantly improved insulin sensitivity through (1) inhibiting the proteolytic cleavage of SREBPs-1 and SREBPs-2 without affecting their precursor mRNA or protein levels, (2) inhibiting free fatty acid β-oxidation and generation of reactive oxygen species through significant inhibition of CPT-1 and UCP-2, and (3) decreasing activity of pancreatic lipase in vivo and in vitro. In conclusion, our findings are the first in the literature to show new mechanisms of the hepatoprotective effect of RES against HFD induced NAFLD in rats.