Creatine supplementation prevents the accumulation of fat in the livers of rats fed a high-fat diet

Creatine Supplementation Potentiates Exercise Protective Effects against Doxorubicin-Induced Hepatotoxicity in Mice

We tested the hypothesis that creatine supplementation may potentiate exercise’s protective effects against doxorubicin-induced hepatotoxicity. Thirty-eight Swiss mice were randomly allocated into five groups: control (C, n = 7), exercised (Ex, n = 7), treated with doxorubicin (Dox, n = 8), treated with doxorubicin and exercised (DoxEx, n = 8), and treated with doxorubicin, exercised, and supplemented with creatine (DoxExCr, n = 8). Doxorubicin was administered weekly (i.p.) for a total dose of 12 mg/kg. Creatine supplementation (2% added to the diet) and strength training (climbing stairs, 3 times a week) were performed for a total of 5 weeks. The results demonstrated that doxorubicin caused hepatotoxicity, which was evidenced by increased (p < 0.05) hepatic markers of inflammation (i.e., TNF-α and IL-6) and oxidative damage, while the redox status (GSH/GSSG) was reduced. The plasma concentrations of liver transaminases were also significantly (p < 0.05) elevated. Furthermore, doxorubicin-treated animals presented hepatic fibrosis and histopathological alterations such as cellular degeneration and the infiltration of interstitial inflammatory cells. Exercise alone partly prevented doxorubicin-induced hepatotoxicity; thus, when combined with creatine supplementation, exercise was able to attenuate inflammation and oxidative stress, morphological alterations, and fibrosis. In conclusion, creatine supplementation potentiates the protective effects of exercise against doxorubicin-induced hepatotoxicity in mice.

Creatine ameliorates high-fat diet-induced obesity by regulation of lipolysis and lipophagy in brown adipose tissue and liver

Diet-induced obesity in mice and humans is commonly associated with an imbalance between energy intake and expenditure. Reportedly, creatine can enhance energy expenditure in brown adipose tissue and reduce hepatic triglycerides accumulation; however, the molecular mechanism underlying the role of exogenous creatine supplementation in regulating lipid droplet mobilization remains elusive. Herein, we employed a high-fat diet (HFD)- induced mouse model to investigate the role of creatine in regulating lipolysis and lipophagy in brown adipose tissue and the liver. Exogenous creatine supplementation ameliorated HFD-induced obesity, increased insulin sensitivity and improved glucose homeostasis. Creatine supplementation enhanced the expression of uncoupling protein 1 (UCP1), cell death-inducing DNA fragmentation factor alpha-like effector A (CIDEA), and other brown adipose tissue-specific thermogenic genes Cpt1a, Gyk, and Pgc1β in brown adipose tissue. Furthermore, creatine inhibited the expression of CIDEA, which promotes hepatic lipid accumulation. Creatine stimulated the expression of triglyceride lipase adipose triglyceride lipase, and phospho-hormone-sensitive lipase (HSL) induced increased lipolysis in brown adipose tissue and the liver. Meanwhile, reduced LC3B expression was accompanied by an increased level of p62 in HFD-fed mice, indicating diminished basal autophagy in brown adipose tissue and the liver; however, creatine enhanced P62/LC3B induced lipophagy in brown adipose tissue and the liver. Collectively, our results suggest that creatine may function as a brown adipose tissue activator to increase whole-body energy metabolism via coordinated lipolysis and lipophagy in brown adipose tissue and the liver.

Creatine Supplementation to Improve Sarcopenia in Chronic Liver Disease: Facts and Perspectives

Creatine supplementation has been one of the most studied and useful ergogenic nutritional support for athletes to improve performance, strength, and muscular mass. Over time creatine has shown beneficial effects in several human disease conditions. This review aims to summarise the current evidence for creatine supplementation in advanced chronic liver disease and its complications, primarily in sarcopenic cirrhotic patients, because this condition is known to be associated with poor prognosis and outcomes. Although creatine supplementation in chronic liver disease seems to be barely investigated and not studied in human patients, its potential efficacy on chronic liver disease is indirectly highlighted in animal models of non-alcoholic fatty liver disease, bringing beneficial effects in the fatty liver. Similarly, encephalopathy and fatigue seem to have beneficial effects. Creatine supplementation has demonstrated effects in sarcopenia in the elderly with and without resistance training suggesting a potential role in improving this condition in patients with advanced chronic liver disease. Creatine supplementation could address several critical points of chronic liver disease and its complications. Further studies are needed to support the clinical burden of this hypothesis.

Creatine supplementation protects against diet-induced non-alcoholic fatty liver but exacerbates alcoholic fatty liver

AIMS

This work investigated the effects of creatine supplementation on different pathways related to the pathogenesis of non-alcoholic fatty liver disease and alcoholic liver disease.

MAIN METHODS

To induce alcoholic liver disease, male Swiss mice were divided into three groups: control, ethanol and ethanol supplemented with creatine. To induce non-alcoholic fatty liver disease, mice were divided into three groups: control, high-fat diet and high-fat diet supplemented with creatine. Each group consisted of eight animals. In both cases, creatine monohydrate was added to the diets (1 %; weight/vol).

KEY FINDINGS

Creatine supplementation prevented high-fat diet-induced non-alcoholic fatty liver disease progression, demonstrated by attenuated liver fat accumulation and liver damage. On the other hand, when combined with ethanol, creatine supplementation up-regulated key genes related to ethanol metabolism, oxidative stress, inflammation and lipid synthesis, and exacerbated ethanol-induced liver steatosis and damage, demonstrated by increased liver fat accumulation and histopathological score, as well as elevated oxidative damage markers and inflammatory mediators.

SIGNIFICANCE

Our results clearly demonstrated creatine supplementation exerts different outcomes in relation to non-alcoholic fatty liver disease and alcoholic liver disease, namely it protects against high-fat diet-induced non-alcoholic fatty liver disease but exacerbates ethanol-induced alcoholic liver disease. The exacerbating effects of the creatine and ethanol combination appear to be related to oxidative stress and inflammation-mediated up-regulation of ethanol metabolism.

Trend in creatinine determining methods: Conventional methods to molecular‐based methods

Renal failure (RF) disease is ranked as one of the most prevalent diseases with severe morbidity and mortality. Early diagnosis of RF leads to subsequent control of disease to reduce the poor prognosis. The level of sera creatinine is considered as a significant biomarker for kidney biofunction, which is routinely detected by the Jaffe reaction. The normal range for creatinine in the blood may be 0.84‐1.21 mg/dL. Low accuracy, insufficient sensitivity, explosive and toxicity of picric acid, and pseudo‐interaction with nonspecific elements such as ammonium ions in the Jaffe method lead to the development of various techniques for precise detection of creatinine such as spectroscopic, electrochemical, and chromatography approaches and sensors based on enzymes, molecular imprinted polymer and nanoparticles, etc. Based on previously established results, they are trying to construct sensors with high accuracy, optimum sensitivity, acceptable linear/calibration range, and limit of detection, which are small in size and applicable by the patient him/herself (point‐of‐care testing). By comparing the results of research, a molecularly imprinted electrochemiluminescence‐based sensor with linear/calibration range of 5‐1 mMconcentration of creatinine and the detection limit of 0.5 nM has the best detectable resolution with 2 million measurable points. In this paper, we will review the recently developed methods for measuring creatinine concentration and renal biofunction.

S-adenosylmethionine upregulates the angiotensin receptor-binding protein ATRAP via the methylation of HuR in NAFLD

Nonalcoholic fatty liver disease (NAFLD) has emerged globally and is associated with inflammatory signaling. The underlying mechanisms remain poorly delineated, although NAFLD has attracted considerable attention and been extensively investigated. Recent publications have determined that angiotensin II (Ang II) plays an important role in stimulating NAFLD progression by causing lipid metabolism disorder and insulin resistance through its main receptor, Ang II type 1 receptor (AT1R). Herein, we explored the effect of supplementary S-adenosylmethionine (SAM), which is the main biological methyl donor in mammalian cells, in regulating AT1R-associated protein (ATRAP), which is the negative regulator of AT1R. We found that SAM was depleted in NAFLD and that SAM supplementation ameliorated steatosis. In addition, in both high-fat diet-fed C57BL/6 rats and L02 cells treated with oleic acid (OA), ATRAP expression was downregulated at lower SAM concentrations. Mechanistically, we found that the subcellular localization of human antigen R (HuR) was determined by the SAM concentration due to protein methylation modification. Moreover, HuR was demonstrated to directly bind ATRAP mRNA and control its nucleocytoplasmic shuttling. Thus, SAM was suggested to upregulate ATRAP protein expression by maintaining the export of its mRNA from the nucleus. Taken together, our findings suggest that SAM can positively regulate ATRAP in NAFLD and may have various potential benefits for the treatment of NAFLD.

An Electrochemical Approach for the Selective Detection of Cancer Metabolic Creatine Biomarker with Porous Nano-Formulated CMNO Materials Decorated Glassy Carbon Electrode

The facile wet-chemical technique was used to prepare the low-dimensional nano-formulated porous mixed metal oxide nanomaterials (CuO.Mn2O3.NiO; CMNO NMs) in an alkaline medium at low temperature. Detailed structural, morphological, crystalline, and functional characterization of CMNO NMs were performed by X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-vis), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDS) analyses. An efficient and selective creatine (CA) sensor probe was fabricated by using CMNO NMs decorated onto glassy carbon electrode (GCE) as CMNO NMs/GCE by using Nafion adhesive (5% suspension in ethanol). The relation of current versus the concentration of CA was plotted to draw a calibration curve of the CMNO NMs/GCE sensor probe, which was found to have a very linear value (r2 = 0.9995) over a large dynamic range (LDR: 0.1 nM~0.1 mM) for selective CA detection. The slope of LDR by considering the active surface area of GCE (0.0316 cm2) was applied to estimate the sensor sensitivity (14.6308 µAµM-1 cm-2). Moreover, the detection limit (21.63 ± 0.05 pM) of CMNO MNs modified GCE was calculated from the signal/noise (S/N) ratio at 3. As a CA sensor probe, it exhibited long-term stability, good reproducibility, and fast response time in the detection of CA by electrochemical approach. Therefore, this research technique is introduced as a promising platform to develop an efficient sensor probe for cancer metabolic biomarker by using nano-formulated mixed metal oxides for biochemical as well as biomedical research for the safety of health care fields.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) dysregulates hepatic one carbon metabolism during the progression of steatosis to steatohepatitis with fibrosis in mice

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a persistent environmental contaminant, induces steatosis that can progress to steatohepatitis with fibrosis, pathologies that parallel stages in the development of non-alcoholic fatty liver disease (NAFLD). Coincidently, one carbon metabolism (OCM) gene expression and metabolites are often altered during NAFLD progression. In this study, the time- and dose-dependent effects of TCDD were examined on hepatic OCM in mice. Despite AhR ChIP-seq enrichment at 2 h, OCM gene expression was not changed within 72 h following a bolus dose of TCDD. Dose-dependent repression of methionine adenosyltransferase 1A (Mat1a), adenosylhomocysteinase (Achy) and betaine-homocysteine S-methyltransferase (Bhmt) mRNA and protein levels following repeated treatments were greater at 28 days compared to 8 days. Accordingly, levels of methionine, betaine, and homocysteic acid were dose-dependently increased, while S-adenosylmethionine, S-adenosylhomocysteine, and cystathionine exhibited non-monotonic dose-dependent responses consistent with regulation by OCM intermediates and repression of glycine N-methyltransferase (Gnmt). However, the dose-dependent effects on SAM-dependent metabolism of polyamines and creatine could not be directly attributed to alterations in SAM levels. Collectively, these results demonstrate persistent AhR activation disrupts hepatic OCM metabolism at the transcript, protein and metabolite levels within context of TCDD-elicited progression of steatosis to steatohepatitis with fibrosis.

One-Carbon Metabolism in Fatty Liver Disease and Fibrosis: One-Carbon to Rule Them All

Nonalcoholic fatty liver disease (NAFLD) is a term used to characterize a range of disease states that involve the accumulation of fat in the liver but are not associated with excessive alcohol consumption. NAFLD is a prevalent disease that can progress to organ damage like liver cirrhosis and hepatocellular carcinoma. Many animal models have demonstrated that one-carbon metabolism is strongly associated with NAFLD. Phosphatidylcholine is an important phospholipid that affects hepatic lipid homeostasis and de novo synthesis of this phospholipid is associated with NAFLD. However, one-carbon metabolism serves to support all cellular methylation reactions and catabolism of methionine, serine, glycine, choline, betaine, tryptophan, and histidine. Several different pathways within one-carbon metabolism that play important roles in regulating energy metabolism and immune function have received less attention in the study of fatty liver disease and fibrosis. This review examines what we have learned about hepatic lipid metabolism and liver damage from the study of one-carbon metabolism thus far and highlights unexplored opportunities for future research.

Predictors for imaging progression on chest CT from coronavirus disease 2019 (COVID-19) patients

OBJECTIVE

This study aimed to investigate the potential parameters associated with imaging progression on chest CT from coronavirus disease 19 (COVID-19) patients.

RESULTS

The average age of 273 COVID-19 patients enrolled with imaging progression were older than those without imaging progression (p = 0.006). The white blood cells, platelets, neutrophils and acid glycoprotein were all decreased in imaging progression patients (all p < 0.05), and monocytes were increased (p = 0.025). The parameters including homocysteine, urea, creatinine and serum cystatin C were significantly higher in imaging progression patients (all p < 0.05), while eGFR decreased (p < 0.001). Monocyte-lymphocyte ratio (MLR) was significantly higher in imaging progression patients compared to that in imaging progression-free ones (p < 0.001). Logistic models revealed that age, MLR, homocysteine and period from onset to admission were factors for predicting imaging progression on chest CT at first week from COVID-19 patients (all p < 0.05).

CONCLUSION

Age, MLR, homocysteine and period from onset to admission could predict imaging progression on chest CT from COVID-19 patients.

METHODS

The primary outcome was imaging progression on chest CT. Baseline parameters were collected at the first day of admission. Imaging manifestations on chest CT were followed-up at (6±1) days.

Effect of divergence in residual feed intake on expression of lipid metabolism-related genes in the liver of meat-type ducks1

Lipid metabolism is considered one of the important factors affecting residual feed intake (RFI). However, the relationship between RFI and expression of lipid metabolism-related genes is unknown in meat-type ducks. To address this issue, a total of 1,000 male meat-type ducks with similar body weight were randomly selected to measure body weight gain and feed intake from 21 to 42 d of age to estimate RFI. The 8 greatest- (high RFI [HRFI]) and lowest- (low RFI [LRFI]) ranking birds were then selected for the present study. Relative expressions of key genes, namely sirtuin 1 (Sirt1), forkhead box O1 (Foxo1), peroxisome proliferator-activated receptor gamma (PPARγ), sterol regulatory element-binding transcription factor 1c (SREBP-1c), fas cell surface death receptor (FAS), acetyl-CoA carboxylase alpha (ACC), carnitine palmitoyltransferase 1A (CPT1A), and acyl-CoA oxidase 1 (ACOX1), were then determined in the HRFI and LRFI ducks by quantitative PCR. The results showed that RFI, feed conversion ratio (FCR), and average daily feed intake (ADFI) were significantly lower (P < 0.05) in LRFI ducks than in HRFI ducks. In addition, expression of Sirt1, Foxo1, CPT1A, and ACOX1 were significantly higher in LRFI ducks than in HRFI ducks (P < 0.05), whereas PPARγ and FAS expression levels were significantly lower in LRFI ducks than in HRFI ducks (P < 0.01). Correlation analysis showed that Sirt1, CPT1A, and ACOX1 expressions were significantly negatively correlated with FCR (r = -0.81 to -0.93; P < 0.01), whereas PPARγ and FAS expressions were significantly positively correlated with FCR (r = 0.74 to 0.87; P < 0.01). PPARγ expression was significantly positively correlated with RFI (r = 0.83; P < 0.01), whereas CPT1A and ACOX1 expressions were significantly negatively correlated with RFI (r = -0.84 to -0.89; P < 0.01). Sirt1 mRNA expression was positively correlated with Foxo1, CPT1A, and ACOX1 mRNA expression (r = 0.78 to 0.92; P < 0.01). Association of Foxo1 with CPT1A and ACOX1 was positive (r = 0.88 to 0.96; P < 0.01). These results suggest that genes related to fatty acid oxidation are upregulated in the liver of ducks with high feed efficiency, while genes associated with lipid synthesis are downregulated. Furthermore, the inclusion of lipid metabolism-related genes in future breeding programs might be beneficial for selecting ducks with greater feed efficiency phenotype.

Characteristics of Selected Antioxidative and Bioactive Compounds in Meat and Animal Origin Products

Meat and meat products have a high nutritional value. Besides major components, meat is rich in bioactive components, primarily taurine, l-carnitine, choline, alpha-lipoic acid, conjugated linoleic acid, glutathione, creatine, coenzyme Q10 and bioactive peptides. Many studies have reported their antioxidant and health-promoting properties connected with their lipid-lowering, antihypertensive, anti-inflammatory, immunomodulatory activity and protecting the organism against oxidative stress. The antioxidant activity of meat components results, among others, from the capability of scavenging reactive oxygen and nitrogen species, forming complexes with metal ions and protecting cells against damage. This review is focused to gather accurate information about meat components with antioxidant and biological activity.

Metabolic signatures suggest o-phosphocholine to UDP-N-acetylglucosamine ratio as a potential biomarker for high-glucose and/or palmitate exposure in pancreatic β-cells

INTRODUCTION

Chronic exposure to high-glucose and free fatty acids (FFA) alone/or in combination; and the resulting gluco-, lipo- and glucolipo-toxic conditions, respectively, have been known to induce dysfunction and apoptosis of β-cells in Diabetes. The molecular mechanisms and the development of biomarkers that can be used to predict similarities and differences behind these conditions would help in easier and earlier diagnosis of Diabetes.

OBJECTIVES

This study aims to use metabolomics to gain insight into the mechanisms by which β-cells respond to excess-nutrient stress and identify associated biomarkers.

METHODS

INS-1E cells were cultured in high-glucose, palmitate alone/or in combination for 24 h to mimic gluco-, lipo- and glucolipo-toxic conditions, respectively. Biochemical and cellular experiments were performed to confirm the establishment of these conditions. To gain molecular insights, abundant metabolites were identified and quantified using ¹H-NMR.

RESULTS

No loss of cellular viability was observed in high-glucose while exposure to FFA alone/in combination with high-glucose was associated with increased ROS levels, membrane damage, lipid accumulation, and DNA double-strand breaks. Forty-nine abundant metabolites were identified and quantified using ¹H-NMR. Chemometric pair-wise analysis in glucotoxic and lipotoxic conditions, when compared with glucolipotoxic conditions, revealed partial overlap in the dysregulated metabolites; however, the dysregulation was more significant under glucolipotoxic conditions.

CONCLUSION

The current study compared gluco-, lipo- and glucolipotoxic conditions in parallel and elucidated differences in metabolic pathways that play major roles in Diabetes. o-phosphocholine and UDP-N-acetylglucosamine were identified as common dysregulated metabolites and their ratio was proposed as a potential biomarker for these conditions.

Creatine supplementation in Walker-256 tumor-bearing rats prevents skeletal muscle atrophy by attenuating systemic inflammation and protein degradation signaling

PURPOSE

The aim of this study was to investigate the effects of creatine supplementation on muscle wasting in Walker-256 tumor-bearing rats.

METHODS

Wistar rats were randomly assigned into three groups (n = 10/group): control (C), tumor bearing (T), and tumor bearing supplemented with creatine (TCr). Creatine was provided in drinking water for a total of 21 days. After 11 days of supplementation, tumor cells were implanted subcutaneously into T and TCr groups. The animals' weight, food and water intake were evaluated along the experimental protocol. After 10 days of tumor implantation (21 total), animals were euthanized for inflammatory state and skeletal muscle cross-sectional area measurements. Skeletal muscle components of ubiquitin-proteasome pathways were also evaluated using real-time PCR and immunoblotting.

RESULTS

The results showed that creatine supplementation protected tumor-bearing rats against body weight loss and skeletal muscle atrophy. Creatine intake promoted lower levels of plasma TNF-α and IL-6 and smaller spleen morphology changes such as reduced size of white pulp and lymphoid follicle compared to tumor-bearing rats. In addition, creatine prevented increased levels of skeletal muscle Atrogin-1 and MuRF-1, key regulators of muscle atrophy.

CONCLUSION

Creatine supplementation prevents skeletal muscle atrophy by attenuating tumor-induced pro-inflammatory environment, a condition that minimizes Atrogin-1 and MuRF-1-dependent proteolysis.

Methyl ferulic acid attenuates ethanol-induced hepatic steatosis by regulating AMPK and FoxO1 Pathways in Rats and L-02 cells

Methyl ferulic acid (MFA) is a biologically active monomer extracted and purified from the Chinese herbal medicine Securidaca inappendiculata hasskarl. The previously studies showed that MFA improved acute liver injury induced by ethanol. However, the effect of MFA on ethanol-induced hepatic steatosis in alcoholic liver disease (ALD) still remains unclear. The current study was aimed at elucidating the effect of MFA on alcohol-induced hepatic steatosis and the underlying mechanisms. Human hepatocyte L-02 cells exposed to 200 mM ethanol for 24 h to simulate alcoholic steatosis in vitro. SD rats were fed a Lieber-DeCarli diet containing 5% (w/v) alcohol for 16 weeks to induce alcoholic liver disease in vivo. We examined the effect of MFA on ethanol-induced lipid deposition in L-02 cells and SD rats. The results showed that MFA reduced the accumulation of lipid in L-02 cells, improved alcoholic liver injury in rats, alleviated hepatic pathological lesions, and reduced lipid deposition in rat serum and liver. Further studies suggest that MFA reduces lipid synthesis by activating AMPK-ACC/MAPK-FoxO1 pathway. In addition, MFA also promotes lipid oxidation by up-regulating the expression of SIRT1, PPAR-α, and CPT-1α. Taken together, MFA ameliorates ethanol-induced hepatic steatosis by activating AMPK-ACC/MAPK-FoxO1 pathway and up-regulating the expression levels of SIRT1, PPAR-α, and CPT-1α.

Acute exercise alters homocysteine plasma concentration in an intensity-dependent manner due increased methyl flux in liver of rats

PURPOSE

We aimed to determine the effects of different intensities of acute exercise on Hcy plasma levels, and the exercise-induced changes in Hcy liver metabolism.

METHOD

First, thirty-two Wistar rats were randomly submitted to an acute bout of swimming exercise carrying a load of 2% (n=8), 4% (n=8) and 6% (n=8) of their total body weight attached in their tail. Control rats remained rested (n=8). Blood samples were taken from tail vein for plasma S-containing amino acids determination before (Rest) and post, 1, 2, 3, 4, 6, and 10h after acute swimming exercise. Second, 56 exercised rats (4% loads) were euthanized before (Rest) and1, 2, 3, 4, 6, and 10h after acute swimming exercise. Blood and liver samples were collected for amino acids and keys genes involved in the Hcy metabolism assay.

RESULTS

Acute exercise increases (P<0.05) plasma Hcy concentration in an intensity-dependent manner (rest 7.7±0.8; 6% load 13.8±3.6; 4% load 12.2±2.9±and 2% load 10.1±2.6, μmol/L); this increase is transient and does not promote hyperhomocysteinemia (<15μmol/L).Exercise-induced increased plasma Hcywas accompanied by the decreased liver S-adenosylmethionine/S-adenosylhomocysteine ratio and elevated MAT1a mRNA content. Acute exercise also caused elevated mRNA of key enzymes of transsulfuration (CBS) and remethylation (BHMT and the MTRR).

CONCLUSION

Our data provided evidence that acute exercise increases plasma Hcy concentration due to the augmented requirement for methylated compounds that increases liver SAM consumption. Also, Hcy remethylation and transsulfuration are coordinately regulated to maintain methyl balance.

Betaine Supplementation Enhances Lipid Metabolism and Improves Insulin Resistance in Mice Fed a High-Fat Diet

Obesity is a major driver of metabolic diseases such as nonalcoholic fatty liver disease, certain cancers, and insulin resistance. However, there are no effective drugs to treat obesity. Betaine is a nontoxic, chemically stable and naturally occurring molecule. This study shows that dietary betaine supplementation significantly inhibits the white fat production in a high-fat diet (HFD)-induced obese mice. This might be due to betaine preventing the formation of new white fat (WAT), and guiding the original WAT to burn through stimulated mitochondrial biogenesis and promoting browning of WAT. Furthermore, dietary betaine supplementation decreases intramyocellular lipid accumulation in HFD-induced obese mice. Further analysis shows that betaine supplementation reduced intramyocellular lipid accumulation might be associated with increasing polyunsaturated fatty acids (PUFA), fatty acid oxidation, and the inhibition of fatty acid synthesis in muscle. Notably, by performing insulin-tolerance tests (ITTs) and glucose-tolerance tests (GTTs), dietary betaine supplementation could be observed for improvement of obesity and non-obesity induced insulin resistance. Together, these findings could suggest that inhibiting WAT production, intramyocellular lipid accumulation and inflammation, betaine supplementation limits HFD-induced obesity and improves insulin resistance.

Creatine supplementation to total parenteral nutrition improves creatine status and supports greater liver and kidney protein synthesis in neonatal piglets

BackgroundCreatine is not included in commercial pediatric parenteral products; the entire creatine requirement must be met by de novo synthesis from arginine during parenteral nutrition (PN). Poor arginine status is common during PN in neonates, which may compromise creatine accretion. We hypothesized that creatine supplementation will improve creatine status and spare arginine in PN-fed piglets.MethodsPiglets (3-5-day (d) old) were provided PN with or without creatine for 14 d. Tissue concentrations of creatine metabolites and activities of creatine-synthesizing enzymes, as well as tissue protein synthesis rates and liver lipid parameters, were measured.ResultsCreatine provision lowered kidney and pancreas L-arginine:glycine amidinotransferase (AGAT, EC number 2.1.4.1) activities and plasma guanidinoacetic acid (GAA) concentration, suggesting the downregulation of de novo creatine synthesis. Creatine increased plasma creatine concentrations to sow-fed reference levels and increased the creatine concentrations in most tissues, but not in the brain. PN creatine resulted in greater protein synthesis in the liver and the kidney, but not in the pancreas, skeletal muscle, or gut. Creatine supplementation also reduced liver cholesterol concentrations, but not triglyceride or total fat.ConclusionThe addition of creatine to PN may optimize the accretion of creatine and reduce the metabolic burden of creatine synthesis in rapidly growing neonates.

Preventive effects of indole-3-carbinol against alcohol-induced liver injury in mice via antioxidant, anti-inflammatory, and anti-apoptotic mechanisms: Role of gut-liver-adipose tissue axis

Indole-3-carbinol (I3C), found in Brassica family vegetables, exhibits antioxidant, anti-inflammatory, and anti-cancerous properties. Here, we aimed to evaluate the preventive effects of I3C against ethanol (EtOH)-induced liver injury and study the protective mechanism(s) by using the well-established chronic-plus-binge alcohol exposure model. The preventive effects of I3C were evaluated by conducting various histological, biochemical, and real-time PCR analyses in mouse liver, adipose tissue, and colon, since functional alterations of adipose tissue and intestine can also participate in promoting EtOH-induced liver damage. Daily treatment with I3C alleviated EtOH-induced liver injury and hepatocyte apoptosis, but not steatosis, by attenuating elevated oxidative stress, as evidenced by the decreased levels of hepatic lipid peroxidation, hydrogen peroxide, CYP2E1, NADPH-oxidase, and protein acetylation with maintenance of mitochondrial complex I, II, and III protein levels and activities. I3C also restored the hepatic antioxidant capacity by preventing EtOH-induced suppression of glutathione contents and mitochondrial aldehyde dehydrogenase-2 activity. I3C preventive effects were also achieved by attenuating the increased levels of hepatic proinflammatory cytokines, including IL1β, and neutrophil infiltration. I3C also attenuated EtOH-induced gut leakiness with decreased serum endotoxin levels through preventing EtOH-induced oxidative stress, apoptosis of enterocytes, and alteration of tight junction protein claudin-1. Furthermore, I3C alleviated adipose tissue inflammation and decreased free fatty acid release. Collectively, I3C prevented EtOH-induced liver injury via attenuating the damaging effect of ethanol on the gut-liver-adipose tissue axis. Therefore, I3C may also have a high potential for translational research in treating or preventing other types of hepatic injury associated with oxidative stress and inflammation.

Dietary creatine supplementation lowers hepatic triacylglycerol by increasing lipoprotein secretion in rats fed high-fat diet

Recent studies have shown that dietary creatine supplementation can prevent lipid accumulation in the liver. Creatine is a small molecule that plays a large role in energy metabolism, but since the enzyme creatine kinase is not present in the liver, the classical role in energy metabolism does not hold in this tissue. Fat accumulation in the liver can lead to the development of nonalcoholic fatty liver disease (NAFLD), a progressive disease that is prevalent in humans. We have previously reported that creatine can directly influence lipid metabolism in cell culture to promote lipid secretion and oxidation. Our goal in the current study was to determine whether similar mechanisms that occur in cell culture were present in vivo. We also sought to determine whether dietary creatine supplementation could be effective in reversing steatosis. Sprague-Dawley rats were fed a high-fat diet or a high-fat diet supplemented with creatine for 5 weeks. We found that rats supplemented with creatine had significantly improved rates of lipoprotein secretion and alterations in mitochondrial function that were consistent with greater oxidative capacity. We also find that introducing creatine into a high-fat diet halted hepatic lipid accumulation in rats with fatty liver. Our results support our previous report that liver cells in culture with creatine secrete and oxidize more oleic acid, demonstrating that dietary creatine can effectively change hepatic lipid metabolism by increasing lipoprotein secretion and oxidation in vivo. Our data suggest that creatine might be an effective therapy for NAFLD.

Alcohol, microbiome, life style influence alcohol and non-alcoholic organ damage

This paper is based upon the "8th Charles Lieber's Satellite Symposium" organized by Manuela G. Neuman at the Research Society on Alcoholism Annual Meeting, on June 25, 2016 at New Orleans, Louisiana, USA. The integrative symposium investigated different aspects of alcohol-induced liver disease (ALD) as well as non-alcohol-induced liver disease (NAFLD) and possible repair. We revealed the basic aspects of alcohol metabolism that may be responsible for the development of liver disease as well as the factors that determine the amount, frequency and which type of alcohol misuse leads to liver and gastrointestinal diseases. We aimed to (1) describe the immuno-pathology of ALD, (2) examine the role of genetics in the development of alcoholic hepatitis (ASH) and NAFLD, (3) propose diagnostic markers of ASH and non-alcoholic steatohepatitis (NASH), (4) examine age and ethnic differences as well as analyze the validity of some models, (5) develop common research tools and biomarkers to study alcohol-induced effects, 6) examine the role of alcohol in oral health and colon and gastrointestinal cancer and (7) focus on factors that aggravate the severity of organ-damage. The present review includes pre-clinical, translational and clinical research that characterizes ALD and NAFLD. Strong clinical and experimental evidence lead to recognition of the key toxic role of alcohol in the pathogenesis of ALD with simple fatty infiltrations and chronic alcoholic hepatitis with hepatic fibrosis or cirrhosis. These latter stages may also be associated with a number of cellular and histological changes, including the presence of Mallory's hyaline, megamitochondria, or perivenular and perisinusoidal fibrosis. Genetic polymorphisms of ethanol metabolizing enzymes and cytochrome p450 (CYP) 2E1 activation may change the severity of ASH and NASH. Other risk factors such as its co-morbidities with chronic viral hepatitis in the presence or absence of human deficiency virus were discussed. Dysregulation of metabolism, as a result of ethanol exposure, in the intestine leads to colon carcinogenesis. The hepatotoxic effects of ethanol undermine the contribution of malnutrition to the liver injury. Dietary interventions such as micro and macronutrients, as well as changes to the microbiota have been suggested. The clinical aspects of NASH, as part of the metabolic syndrome in the aging population, have been presented. The symposium addressed mechanisms and biomarkers of alcohol induced damage to different organs, as well as the role of the microbiome in this dialog. The microbiota regulates and acts as a key element in harmonizing immune responses at intestinal mucosal surfaces. It is known that microbiota is an inducer of proinflammatory T helper 17 cells and regulatory T cells in the intestine. The signals at the sites of inflammation mediate recruitment and differentiation in order to remove inflammatory inducers and promote tissue homeostasis restoration. The change in the intestinal microbiota also influences the change in obesity and regresses the liver steatosis. Evidence on the positive role of moderate alcohol consumption on heart and metabolic diseases as well on reducing steatosis have been looked up. Moreover nutrition as a therapeutic intervention in alcoholic liver disease has been discussed. In addition to the original data, we searched the literature (2008-2016) for the latest publication on the described subjects. In order to obtain the updated data we used the usual engines (Pub Med and Google Scholar). The intention of the eighth symposia was to advance the international profile of the biological research on alcoholism. We also wish to further our mission of leading the forum to progress the science and practice of translational research in alcoholism.

Creatine Supplementation Does Not Prevent the Development of Alcoholic Steatosis

BACKGROUND

Alcohol-induced reduction in the hepatocellular S-adenosylmethionine (SAM):S-adenosylhomocysteine (SAH) ratio impairs the activities of many SAM-dependent methyltransferases. These impairments ultimately lead to the generation of several hallmark features of alcoholic liver injury including steatosis. Guanidinoacetate methyltransferase (GAMT) is an important enzyme that catalyzes the final reaction in the creatine biosynthetic process. The liver is a major site for creatine synthesis which places a substantial methylation burden on this organ as GAMT-mediated reactions consume as much as 40% of all the SAM-derived methyl groups. We hypothesized that dietary creatine supplementation could potentially spare SAM, preserve the hepatocellular SAM:SAH ratio, and thereby prevent the development of alcoholic steatosis and other consequences of impaired methylation reactions.

METHODS

For these studies, male Wistar rats were pair-fed the Lieber-DeCarli control or ethanol (EtOH) diet with or without 1% creatine supplementation. At the end of 4 to 5 weeks of feeding, relevant biochemical and histological analyses were performed.

RESULTS

We observed that creatine supplementation neither prevented alcoholic steatosis nor attenuated the alcohol-induced impairments in proteasome activity. The lower hepatocellular SAM:SAH ratio seen in the EtOH-fed rats was also not normalized or SAM levels spared when these rats were fed the creatine-supplemented EtOH diet. However, a >10-fold increased level of creatine was observed in the liver, serum, and hearts of rats fed the creatine-supplemented diets.

CONCLUSIONS

Overall, dietary creatine supplementation did not prevent alcoholic liver injury despite its known efficacy in preventing high-fat-diet-induced steatosis. Betaine, a promethylating agent that maintains the hepatocellular SAM:SAH, still remains our best option for treating alcoholic steatosis.

Prolonged feeding with guanidinoacetate, a methyl group consumer, exacerbates ethanol-induced liver injury

AIM

To investigate the hypothesis that exposure to guanidinoacetate (GAA, a potent methyl-group consumer) either alone or combined with ethanol intake for a prolonged period of time would cause more advanced liver pathology thus identifying methylation defects as the initiator and stimulator for progressive liver damage.

METHODS

Adult male Wistar rats were fed the control or ethanol Lieber DeCarli diet in the absence or presence of GAA supplementation. At the end of 6 wk of the feeding regimen, various biochemical and histological analyses were conducted.

RESULTS

Contrary to our expectations, we observed that GAA treatment alone resulted in a histologically normal liver without evidence of hepatosteatosis despite persistence of some abnormal biochemical parameters. This protection could result from the generation of creatine from the ingested GAA. Ethanol treatment for 6 wk exhibited changes in liver methionine metabolism and persistence of histological and biochemical defects as reported before. Further, when the rats were fed the GAA-supplemented ethanol diet, similar histological and biochemical changes as observed after 2 wk of combined treatment, including inflammation, macro- and micro-vesicular steatosis and a marked decrease in the methylation index were noted. In addition, rats on the combined treatment exhibited increased liver toxicity and even early fibrotic changes in a subset of animals in this group. The worsening liver pathology could be related to the profound reduction in the hepatic methylation index, an increased accumulation of GAA and the inability of creatine generated to exert its hepato-protective effects in the setting of ethanol.

CONCLUSION

To conclude, prolonged exposure to a methyl consumer superimposed on chronic ethanol consumption causes persistent and pronounced liver damage.

Whey protein supplementation increases methionine intake but not homocysteine plasma concentration in rats

The purpose of this study was to examine the effects of whey protein supplementation on homocysteine (Hcy) metabolism and liver oxidative stress in rats. Twenty-four rats were divided into 3 groups (n = 8) to receive one of the following diets for 4 weeks: control diet (C), whey protein-composed diet (WP), and whey protein-supplemented diet (WPS). The C and WP diets consisted of AIN-93 with 20% casein and 20% whey protein as protein source, respectively. WPS was AIN-93 (20% casein) supplemented by the addition of 20% (w/w) whey protein. Four weeks of ingesting a WPS diet resulted in a significantly higher (P < 0.05) total protein and methionine intakes. Although a significant increase (P < 0.05) in the hepatic S-adenosylmethionine and S-adenosylhomocysteine levels occurred in WPS group compared with C and WP, no significant change was observed in plasma Hcy concentration between groups. Furthermore, the levels of lipid hydroperoxides and advanced oxidation protein products, known liver oxidative stress markers, were increased in the WPS group compared with the C group. In addition, no change in glutathione liver concentration was observed in any of the groups studied. In conclusion, whey protein supplementation increases methionine intake substantially; however, it does not change plasma Hcy concentrations. On the other hand, increased hepatic oxidative stress markers were observed in whey protein supplemented rats were probably due to high protein intake.

The Pediatric Methionine Requirement Should Incorporate Remethylation Potential and Transmethylation Demands

The metabolic demand for methionine is great in neonates. Indeed, methionine is the only indispensable sulfur amino acid and is required not only for protein synthesis and growth but is also partitioned to a greater extent to transsulfuration for cysteine and taurine synthesis and to >50 transmethylation reactions that serve to methylate DNA and synthesize metabolites, including creatine and phosphatidylcholine. Therefore, the pediatric methionine requirement must accommodate the demands of rapid protein turnover as well as vast nonprotein demands. Because cysteine spares the methionine requirement, it is likely that the dietary provision of transmethylation products can also feasibly spare methionine. However, understanding the requirement of methionine is further complicated because demethylated methionine can be remethylated by the dietary methyl donors folate and betaine (derived from choline). Intakes of dietary methyl donors are highly variable, which is of particular concern for newborns. It has been demonstrated that many populations have enhanced requirements for these nutrients, and nutrient fortification may exacerbate this phenomenon by selecting phenotypes that increase methyl requirements. Moreover, higher transmethylation rates can limit methyl supply and affect other transmethylation reactions as well as protein synthesis. Therefore, careful investigations are needed to determine how remethylation and transmethylation contribute to the methionine requirement. The purpose of this review is to support our hypothesis that dietary methyl donors and consumers can drive methionine availability for protein synthesis and transmethylation reactions. We argue that nutritional strategies in neonates need to ensure that methionine is available to meet requirements for growth as well as for transmethylation products.

Creatine supplementation decreases plasma lipid peroxidation markers and enhances anaerobic performance in rats

OBJECTIVE

The study was to investigate the effects of creatine (Cr) supplementation on oxidative stress markers and anaerobic performance in rats.

METHODS

Sixty-four rats (Wistar) were divided into two groups: C, anaerobic exercised group (n = 32) and Cr, anaerobic exercised group supplemented with creatine (n = 32). Cr supplementation consisted of the addition of 2% Cr monohydrate to the diet. After 28 days, the rats performed acute exercise (6 × 30 seconds of vertical jumps in the water with 30 seconds rest and 50% of total body weight load attached in the back). The animals were euthanized before (pre) and at 0, 2, and 6 hours (n = 8) after acute exercise.

RESULTS

Acute exercise induced an increase in plasma malondialdehyde (MDA) and advanced oxidation protein products (AOPP), as well as increased total lipid hydroperoxides and AOPP in gastrocnemius muscle. Cr supplementation inhibited the formation of MDA and lipid hydroperoxides in plasma. However, the antioxidant action of Cr was observed only against AOPP in gastrocnemius muscle. Cr supplementation also increased (P < 0.05) anaerobic performance compared to the C group.

CONCLUSION

Cr supplementation is able to inhibit the increase in plasma lipid peroxidation markers induced by high-intensity and short-duration exercise in rats; equivalent actions, however, were not observed fully in muscle tissue.

The role of dietary creatine

The daily requirement of a 70-kg male for creatine is about 2 g; up to half of this may be obtained from a typical omnivorous diet, with the remainder being synthesized in the body Creatine is a carninutrient, which means that it is only available to adults via animal foodstuffs, principally skeletal muscle, or via supplements. Infants receive creatine in mother's milk or in milk-based formulas. Vegans and infants fed on soy-based formulas receive no dietary creatine. Plasma and muscle creatine levels are usually somewhat lower in vegetarians than in omnivores. Human intake of creatine was probably much higher in Paleolithic times than today; some groups with extreme diets, such as Greenland and Alaskan Inuit, ingest much more than is currently typical. Creatine is synthesized from three amino acids: arginine, glycine and methionine (as S-adenosylmethionine). Humans can synthesize sufficient creatine for normal function unless they have an inborn error in a creatine-synthetic enzyme or a problem with the supply of substrate amino acids. Carnivorous animals, such as lions and wolves, ingest much larger amounts of creatine than humans would. The gastrointestinal tract and the liver are exposed to dietary creatine in higher concentrations before it is assimilated by other tissues. In this regard, our observations that creatine supplementation can prevent hepatic steatosis (Deminice et al. J Nutr 141:1799-1804, 2011) in a rodent model may be a function of the route of dietary assimilation. Creatine supplementation has also been reported to improve the intestinal barrier function of the rodent suffering from inflammatory bowel disease.

Creatine supplementation as a possible new therapeutic approach for fatty liver disease: early findings

Over the last few years, consistent data have demonstrated that creatine (Cr) supplementation prevents the accumulation of fat in rat liver as well as the progression of fatty liver disease in different situations. Studies have demonstrated that Cr is effective and prevents fatty liver in high-fat and choline-deficient diets and in hepatoma cells in vitro. Because Cr synthesis is responsible for a considerable consumption of hepatic methyl groups, studies have tested the idea that Cr supplementation could modulate phospholipid formation and VLDL secretion. Studies have also demonstrated Cr is able to modulate the expression of key genes related to fatty acid oxidation in hepatocyte cell culture and in rat liver. However, to date, the mechanism by which Cr exerts protective effects against fatty liver is poorly understood. Therefore, the present review aims to summarize the studies involving the therapeutic use of Cr supplementation on fatty liver disease and to explore the mechanisms involved in one-carbon and fatty acid metabolism for the preventive effects of Cr supplementation on fat liver accumulation. Although a small number of studies have been conducted to date, we consider Cr as a new and promising therapeutic strategy to control fat accumulation in the liver as well as the progression of fatty liver disease.

E2F8 promotes hepatic steatosis through FABP3 expression in diet-induced obesity in zebrafish

Background

Diet-induced hepatic steatosis is highly associated with nonalcoholic fatty liver disease, which is related to the development of metabolic syndrome. While advanced stage nonalcoholic hepatic steatosis and steatohepatitis (NASH) result ultimately in fibrosis and cirrhosis, the molecular basis for lipid droplet formation is poorly understood. Common pathways underlie the pathology of mammalian obesity and the zebrafish diet-induced obesity model (DIO-zebrafish) used in this study.

Methods

Our analysis involved a combination of transcriptome (DNA microarray) and proteome (two-dimensional electrophoresis) methods using liver tissue from DIO-zebrafish to find candidate genes involved in hepatic steatosis. We conducted intraperitoneal injection (i.p.) of morpholino antisense oligonucleotides (MOs) for each gene into DIO-zebrafish. We also conducted in vitro overexpression in human cells. Additionally, we examined gene expression during feeding experiments involving anti-obesity compounds, creatine and anserine.

Results

We found that fatty acid binding protein 3 (fabp3) and E2F transcription factors were upregulated in hepatic steatosis. E2f8 MO i.p. suppressed fabp3 expression in liver, and ameliorated hepatic steatosis. In human cells (HepG2), E2F8 overexpression promoted FABP3 expression. Additionally, co-administration of creatine and anserine suppressed obesity associated phenotypes including hepatic steatosis as indicated by e2f8 and fabp3 down regulation.

Conclusion

We discovered that the e2f8–fabp3 axis is important in the promotion of hepatic steatosis in DIO-zebrafish. The combination of transcriptome and proteome analyses using the disease model zebrafish allow identification of novel pathways involved in human diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-015-0012-7) contains supplementary material, which is available to authorized users.

Elevated homocysteine levels in human immunodeficiency virus-infected patients under antiretroviral therapy: A meta-analysis

AIM: To evaluate the association between the levels of homocysteine (Hcy), folate, vitamin B12 in human immunodeficiency virus (HIV)-infected patients who were treated with antiretroviral therapy (ART) or not treated with ART.

METHODS: The PubMed and Scielo databases were searched. Eligible studies regarding plasma Hcy level in HIV-infected patients were firstly identified. After careful analysis by two independent researches, the identified articles were included in the review according to two outcomes (1) Hcy, folate and vitamin B12 blood concentration in HIV-infected subjects vs health controls and; (2) Hcy blood concentration in HIV-infected subjects under ART vs not treated with ART. RevMan (version 5.2) was employed for data synthesis.

RESULTS: A total of 12 studies were included in outcome 1 (1649 participants, 932 cases and 717 controls). Outcome 1 meta-analysis demonstrated higher plasma Hcy (2.05 µmol/L; 95%CI: 0.10 to 4.00, P < 0.01) and decreased plasma folate concentrations (-2.74 ng/mL; 95%CI: -5.18 to -0.29, P < 0.01) in HIV-infected patients compared to healthy controls. No changes in vitamin B12 plasma concentration were observed between groups. All studies included in the outcome 2 meta-analysis (1167 participants; 404 HIV-infected exposed to ART and 757 HIV-infected non-ART patients) demonstrated higher mean Hcy concentration in subjects HIV-infected under ART compared to non-ART HIV subjects (4.13 µmol/L; 95%CI: 1.34 to 6.92, P < 0.01).

CONCLUSION: This meta-analysis demonstrated that the levels of Hcy and folate, but not vitamin B12, were associated with HIV infection. In addition, Hcy levels were higher in HIV-infected patients who were under ART compared to HIV-infected patients who were not exposed to ART. Our results suggest that hyperhomocysteinemia should be included among the several important metabolic disturbances that are associated with ART in patients with HIV infection.

Betaine alleviates hepatic lipid accumulation via enhancing hepatic lipid export and fatty acid oxidation in rats fed with a high-fat diet

To assess the effects of betaine on hepatic lipid accumulation and investigate the underlying mechanism, thirty-two male Sprague–Dawley rats weighing 100 (sd 2·50) g were divided into four groups, and started on one of four treatments: basal diet, basal diet with betaine administration, high-fat diet and high-fat diet with betaine administration. The results showed that no significant difference of body weight was found among experimental groups. Compared with high-fat diet-fed rats, a betaine supplementation decreased (P< 0·05) hepatic TAG accumulation induced by high-fat diet, which was also supported by hepatic histology results. Additionally, hepatic betaine–homocysteine methyltransferase activity as well as its mRNA abundance and lecithin level were found increased (P< 0·05) by betaine supplementation in both basal diet-fed rats and high-fat diet-fed rats. Betaine administration in high-fat diet-fed rats exhibited a higher (P< 0·05) activity of hepatic carnitine palmitoyltransferase 1 (CPT1) compared with high-fat diet-fed rats. High-fat diet inhibited (P< 0·05) the gene expression of hepatic PPARα and CPT1. However, betaine administration in high-fat diet-fed rats elevated (P< 0·05) the gene expression of PPARα and CPT1. Moreover, concentration, gene and protein expressions of hepatic fibroblast growth factor 21 (FGF21) were increased (P< 0·05) in response to betaine administration in high-fat diet group; meanwhile the gene expression of hepatic AMP-activated protein kinase was increased (P< 0·05) as well. The results suggest that betaine administration enhanced hepatic lipid export and fatty acid oxidation in high-fat diet-fed rats, thus effectively alleviating fat accumulation in the liver.

Creatine supplementation prevents fatty liver in rats fed choline-deficient diet: a burden of one-carbon and fatty acid metabolism

AIM

To examine the effects of creatine (Cr) supplementation on liver fat accumulation in rats fed a choline-deficient diet.

METHODS

Twenty-four rats were divided into 3 groups of 8 based on 4 weeks of feeding an AIN-93 control diet (C), a choline-deficient diet (CDD) or a CDD supplemented with 2% Cr. The CDD diet was AIN-93 without choline.

RESULTS

The CDD significantly increased plasma homocysteine and TNFα concentration, as well as ALT activity. In liver, the CDD enhanced concentrations of total fat (55%), cholesterol (25%), triglycerides (87%), MDA (30%), TNFα (241%) and decreased SAM concentrations (25%) and the SAM/SAH ratio (33%). Cr supplementation prevented all these metabolic changes, except for hepatic SAM and the SAM/SAH ratio. However, no changes in PEMT gene expression or liver phosphatidylcholine levels were observed among the three experimental groups, and there were no changes in hepatic triglyceride transfer protein (MTP) mRNA level. On the contrary, Cr supplementation normalized expression of the transcription factors PPARα and PPARγ that were altered by the CDD. Further, the downstream targets and fatty acids metabolism genes, UCP2, LCAD and CPT1a, were also normalized in the Cr group as compared to CDD-fed rats.

CONCLUSION

Cr supplementation prevented fat liver accumulation and hepatic injures in rats fed with a CDD for 4 weeks. Our results demonstrated that one-carbon metabolism may have a small role in mitigating hepatic fat accumulation by Cr supplementation. The modulation of key genes related to fatty acid oxidation pathway suggests a new mechanism by which Cr prevents liver fat accumulation.

Free triiodothyronine levels are positively associated with non-alcoholic fatty liver disease in euthyroid middle-aged subjects

BACKGROUND

Studies on the relationship between thyroid function and non-alcoholic fatty liver disease (NAFLD) among euthyroid subjects have produced conflicting results.

OBJECTIVES

The aim of this study was to investigate the association between thyroid function and the presence of NAFLD in a large-sample middle-aged euthyroid subjects.

METHODS

A total of 2576 euthyroid subjects who underwent health check-up were included. NAFLD was diagnosed by hepatic ultrasonography. Conventional risk factors for NAFLD were assessed as well as serum levels of TSH, FT3 and FT4.

RESULTS

Levels of FT3 were significantly higher in NAFLD group (5.12 ± 0.58 versus 4.84 ± 0.58 pmol/L, adjusted p = 0.000) than non-NAFLD group, while levels of TSH and FT4 were comparable between NAFLD and non-NAFLD groups (TSH: 2.13 ± 0.90 versus 2.20 ± 0.93 mIU/L, adjusted p = 0.190; FT4: 16.41 ± 2.04 versus 16.18 ± 2.06 pmol/L, adjusted p = 0.146, respectively). Levels of FT3 were positively correlated with components of metabolic syndrome. Multivariate logistic regression analysis revealed that high level of FT3 was an independent predictor for NAFLD (odds ratio: 1.253, p = 0.040). The relationship between FT4 and NAFLD in women was different according to menopausal status, with negative association in pre-menopausal women (OR: 0.777, 95% CI: 0.617-0.979, p = 0.032) and null association in post-menopausal women (OR: 1.037, 95% CI: 0.841-1.277, p = 0.736).

CONCLUSIONS

Our findings suggested that high levels of FT3 were significantly associated with NAFLD among middle-aged euthyroid subjects independently of known metabolic risk factors. A negative correlation of serum FT4 level with NAFLD was only observed in pre-menopausal women.

Creatine reduces hepatic TG accumulation in hepatocytes by stimulating fatty acid oxidation

Non-alcoholic fatty liver disease encompasses a wide spectrum of liver damage including steatosis, non-alcoholic steatohepatitis, fibrosis and cirrhosis. We have previously reported that creatine supplementation prevents hepatic steatosis and lipid peroxidation in rats fed a high-fat diet. In this study, we employed oleate-treated McArdle RH-7777 rat hepatoma cells to investigate the role of creatine in regulating hepatic lipid metabolism. Creatine, but not structural analogs, reduced cellular TG accumulation in a dose-dependent manner. Incubating cells with the pan-lipase inhibitor diethyl p-nitrophenylphosphate (E600) did not diminish the effect of creatine, demonstrating that the TG reduction brought about by creatine does not depend on lipolysis. Radiolabeled tracer experiments indicate that creatine increases fatty acid oxidation and TG secretion. In line with increased fatty acid oxidation, mRNA analysis revealed that creatine-treated cells had increased expression of PPARα and several of its transcriptional targets. Taken together, this study provides direct evidence that creatine reduces lipid accumulation in hepatocytes by the stimulation of fatty acid oxidation and TG secretion.

Diets enriched in trans-11 vaccenic acid alleviate ectopic lipid accumulation in a rat model of NAFLD and metabolic syndrome

Trans11-18:1 (vaccenic acid, VA) is one of the most predominant naturally occurring trans fats in our food chain and has recently been shown to exert hypolipidemic effects in animal models. In this study, we reveal new mechanism(s) by which VA can alter body fat distribution, energy utilization and dysfunctional lipid metabolism in an animal model of obesity displaying features of the metabolic syndrome (MetS). Obese JCR:LA-cp rats were assigned to a control diet that included dairy-derived fat or the control diet supplemented with 1% VA. VA reduced total body fat (-6%), stimulated adipose tissue redistribution [reduced mesenteric fat (-17%) while increasing inguinal fat mass (29%)] and decreased adipocyte size (-44%) versus control rats. VA supplementation also increased metabolic rate (7%) concomitantly with an increased preference for whole-body glucose utilization for oxidation and increased insulin sensitivity [lower HOMA-IR (-59%)]. Further, VA decreased nonalcoholic fatty liver disease activity scores (-34%) and reduced hepatic (-27%) and intestinal (-39%) triglyceride secretion relative to control diet, while exerting differential transcriptional regulation of SREBP1 and FAS amongst other key genes in the liver and the intestine. Adding VA to dairy fat alleviates features of MetS potentially by remodeling adipose tissue and attenuating ectopic lipid accumulation in a rat model of obesity and MetS. Increasing VA content in the diet (naturally or by fortification) may be a useful approach to maximize the health value of dairy-derived fats.

Alcohol consumption decreases rat hepatic creatine biosynthesis via altered guanidinoacetate methyltransferase activity

BACKGROUND

We have previously shown that decreased S-adenosylmethionine (SAM):S-adenosylhomocysteine (SAH) ratio generated in livers of alcohol-fed rats can impair the activities of many SAM-dependent methyltransferases. One such methyltransferase is guanidinoacetate methyltransferase (GAMT) that catalyzes the last step of creatine synthesis. As GAMT is the major utilizer of SAM, the purpose of the study was to examine the effects of ethanol (EtOH) on liver creatine levels and GAMT activity.

METHODS

Male Wistar rats were pair-fed the Lieber-DeCarli control and EtOH diet for 4 to 5 weeks. At the end of the feeding regimen, the liver, kidney, and blood were removed from these rats for subsequent biochemical analyses.

RESULTS

We observed ~60% decrease in creatine levels in the livers from EtOH-fed rats as compared to controls. The reduction in creatine levels correlated with lower SAM:SAH ratio observed in the livers of the EtOH-fed rats. Further, in vitro experiments with cell-free system and hepatic cells revealed it is indeed elevated SAH and lower SAM:SAH ratio that directly impairs GAMT activity and significantly reduces creatine synthesis. EtOH intake also slightly decreases the hepatocellular uptake of the creatine precursor, guanidinoacetate (GAA), and the GAMT enzyme expression that could additionally contribute to reduced liver creatine synthesis. The consequences of impaired hepatic creatine synthesis by chronic EtOH consumption include (i) increased toxicity due to GAA accumulation in the liver; (ii) reduced protection due to lower creatine levels in the liver, and (iii) reduced circulating and cardiac creatine levels.

CONCLUSIONS

Chronic EtOH consumption affects the hepatic creatine biosynthetic pathway leading to detrimental consequences not only in the liver but could also affect distal organs such as the heart that depend on a steady supply of creatine from the liver.

N-3 long-chain PUFA supplementation prevents high fat diet induced mouse liver steatosis and inflammation in relation to PPAR-α upregulation and NF-κB DNA binding abrogation

SCOPE

Dietary n-3 long-chain PUFAs (n-3 LCPUFAs) supplementation was studied in an HFD-induced (HFD is high-fat diet) steatosis and inflammation in relation to peroxisome proliferator-activated receptor alpha (PPAR-α) and nuclear factor κB (NF-κB) signaling.

METHODS AND RESULTS

Male C57BL/6J mice received (i) control diet (10% fat, 20% protein, 70% carbohydrate), (ii) control diet plus n-3 LCPUFAs (daily doses of 108 mg/kg body weight of eicosapentaenoic acid plus 92 mg/kg body weight of docosahexaenoic acid), (iii) HFD (60% fat, 20% protein, 20% carbohydrate), or (iv) HFD plus n-3 LCPUFAs for 12 wk. PPAR-α, tumor necrosis factor alpha (TNF-α), and IL-1β mRNA expression, acyl-CoA oxidase 1 (ACOX1), and carnitine-acyl-CoA transferase 1 (CAT-I) protein contents, and NF-κB DNA binding activity were measured. HFD significantly decreased liver PPAR-α, ACOX1, and CAT-I levels with NF-κB activation, higher TNF-α and IL-1β expression, and steatosis development. These changes were either reduced or normalized to control values in animals subjected to HFD plus n-3 LCPUFAs, with establishment of an inverse association between NF-κB activation and PPAR-α mRNA expression (r = -0.66, p < 0.0001).

CONCLUSION

Data presented indicate that n-3 LCPUFAs supplementation prevents liver steatosis and inflammation induced by HFD, with underlying mechanisms involving enhanced PPAR-α signaling and diminished NF-κB activation.

S-adenosylmethionine is associated with fat mass and truncal adiposity in older adults

S-adenosylmethionine (SAM) is synthesized from methionine, which is abundant in animal-derived protein, in an energy-consuming reaction. SAM and S-adenosylhomocysteine (SAH) correlate with body mass index (BMI). Plasma total concentration of the SAM-associated product cysteine (tCys) correlates with fat mass in humans and cysteine promotes adiposity in animals. In a cross-sectional study of 610 participants, we investigated whether SAM and SAH are associated with BMI via lean mass or fat mass and dietary protein sources as determinants of SAM and tCys concentrations. Plasma SAM was not associated with lean mass, but mean adjusted fat mass increased from 24 kg (95% CI: 22.6, 25.1) to 30 kg (95% CI: 28.7, 31.3) across SAM quartiles (P < 0.001) and trunk fat:total fat ratio increased from 0.48 to 0.52 (P < 0.001). Erythrocyte SAM was also positively associated with fat mass and trunk fat:total fat ratio. The association of SAM with fat mass was not weakened by adjustment for serum tCys, lipids, creatinine, or dietary or lifestyle confounders. Concentrations of the SAM precursor, methionine, and the SAM product, SAH, were not independently associated with adiposity. Intake of animal-derived protein was not related to serum methionine but was positively associated with plasma SAM (partial r = 0.11) and serum tCys (partial r = 0.13; P < 0.05 for both after adjustment for age, gender, and total energy intake). In conclusion, plasma SAM, but not methionine, is independently associated with fat mass and truncal adiposity, suggesting increased conversion of methionine to SAM in obese individuals. Prospective studies are needed to investigate the interactions among dietary energy and animal protein content, SAM concentrations, and change in body weight and cardiometabolic risk.

Evidence-based treatment of guanidinoacetate methyltransferase (GAMT) deficiency

BACKGROUND

Guanidinoacetate methyltransferase (GAMT) deficiency causes cerebral creatine deficiency. Patients can have autistic behavior, seizures, intellectual disability, and severe speech delay. The goal of therapy is to increase creatine while reducing potentially neurotoxic guanidinoacetate concentrations. Here we evaluate how different therapies affect plasma guanidinoacetate levels in patients with GAMT deficiency.

METHODS

Retrospective analysis of data from five new patients with GAMT deficiency (four with delays and seizures, one diagnosed at birth).

RESULTS

The four symptomatic patients had decreased brain creatine by magnetic resonance spectroscopy and three also had abnormal globi pallidi by MRI. GAMT sequencing identified four previously reported mutations and one novel missense mutation (c.233T>A/p.V78E). Treatment with creatine (250-1000 mg/kg/day), ornithine (100-800 mg/kg/day), and sodium benzoate (50-135 mg/kg/day) supplements along with dietary protein restriction (0.8-1.5 g/kg/day) improved seizures and development with all patients becoming verbal. The patient treated at birth remains developmentally normal. Reduction in glycine and increase in ornithine levels significantly decreased plasma guanidinoacetate, with glycine levels being the best predictor of guanidinoacetate levels. In contrast, arginine levels were not significantly correlated with plasma guanidinoacetate.

CONCLUSIONS

Our results show that supplements of creatine, sodium benzoate (to reduce glycine) and ornithine reduce guanidinoacetate levels in patients with GAMT deficiency (dietary therapy was not evaluated in our study). Normal development with early therapy renders GAMT deficiency an ideal candidate for inclusion in newborn screening panels.

Plasma homocysteine levels in HIV-infected men with and without lipodystrophy

OBJECTIVE

Lipodystrophy syndrome is an unexpected clinical manifestation in patients infected with HIV and might be a clinical marker of increased risk for cardiovascular diseases (CVDs). Because hyperhomocysteinemia has been associated with CVD, the goal of the present study was to investigate homocysteine (Hcy) levels and their association with the factors of lipodystrophy syndrome in men with HIV.

METHODS

Hcy metabolism-related molecules were determined in 13 men infected with HIV with lipodystrophy (HIV+LIP), 10 men with HIV without lipodystrophy (HIV), and 10 healthy controls (C).

RESULTS

Significant (P < 0.05) increased Hcy plasma levels were found in HIV (20.5%) and in HIV+LIP (35.2%) compared with the control group. Plasma levels of vitamin B12 (HIV, 26.5%; HIV+LIP, 28.8%) and folate (HIV, 39.1% and HIV+LIP, 49.4%) were significantly (P < 0.05) lower in the two groups of HIV patients compared with control. HIV+LIP men presented raised plasma total sulfur-containing amino acids (20.1%) and lower total plasma thiol (11.3%) than controls. The same was not observed in the HIV group. Spearman's correlation test revealed significant (P < 0.05) association between plasma Hcy and duration of highly active antiretroviral therapy (HAART) and plasma insulin, as well as plasma adiponectin levels.

CONCLUSION

Our results demonstrated that HIV+LIP men were more susceptible to disturbances in Hcy metabolism compared with men infected with HIV without lipodystrophy characteristics. Duration of HAART treatment, elevated plasma insulin, and low levels of adiponectin seem to be relevant for the appearance of these Hcy metabolic disorders.

Metabolic Consequences of TGFb Stimulation in CulturedPrimary Mouse Hepatocytes Screened from Transcript Data with ModeScore

TGFβ signaling plays a major role in the reorganization of liver tissue upon injury and is an important driver of chronic liver disease. This is achieved by a deep impact on a cohort of cellular functions. To comprehensively assess the full range of affected metabolic functions, transcript changes of cultured mouse hepatocytes were analyzed with a novel method (ModeScore), which predicts the activity of metabolic functions by scoring transcript expression changes with 987 reference flux distributions, which yielded the following hypotheses. TGFβ multiplies down-regulation of most metabolic functions occurring in culture stressed controls. This is especially pronounced for tyrosine degradation, urea synthesis, glucuronization capacity, and cholesterol synthesis. Ethanol degradation and creatine synthesis are down-regulated only in TGFβ treated hepatocytes, but not in the control. Among the few TGFβ dependently up-regulated functions, synthesis of various collagens is most pronounced. Further interesting findings include: down-regulation of glucose export is postponed by TGFβ, TGFβ up-regulates the synthesis capacity of ketone bodies only as an early response, TGFβ suppresses the strong up-regulation of Vanin, and TGFβ induces re-formation of ceramides and sphingomyelin.