A combination of caffeine, arginine, soy isoflavones, and L-carnitine enhances both lipolysis and fatty acid oxidation in 3T3-L1 and HepG2 cells in vitro and in KK mice in vivo

Conjugated linoleic acid and L-carnitine combination effects on obesity-related miRNAs in diet-induced obese rats

OBJECTIVES

Obesity is a major global health issue, resulting in significant costs and increased mortality rates. Finding effective treatments for obesity is therefore essential. This study investigated the combined effects of L-Carnitine (LC) and Conjugated Linoleic Acid (CLA) on weight loss and adipose tissue microRNA levels.

SUBJECTS /METHODS

Forty male Wistar rats weighing 150-200 g and about 8 weeks old were fed either a normal fat diet (NFD) or a high-fat diet (HFD) for 8 weeks. Afterwards, the HFD group was randomly divided into four subgroups: control, LC (200 mg kg-1), CLA (500 mg kg-1), and both (n = 8 in each group). The study lasted for an additional 4 weeks. The animals' weights were recorded regularly, and after 12 weeks, miRNAs were extracted from epididymal adipose tissue and analysed using real-time PCR. The miRNA expression levels of miR-27a and miR-143 were compared between groups using Kolmogorov-Smirnov and one-way ANOVA tests in SPSS software.

RESULTS

At the end of the first 8 weeks, the HFD group weighed significantly more than the NFD group. LC significantly decreased weight gain (4.2%) compared to the control group, whereas CLA alone (3.5%) or in combination with LC (3.1%) did not significantly slow weight gain. Real-time PCR results showed that the HFD group had higher miR-143 levels and lower miR-27a levels compared to the NFD group. LC and CLA increased miR-27a expression after 4 weeks, but their combination decreased miR-27a expression. CLA alone reduced miR-143 expression, whereas LC had almost no effect. Their combination also reduced miR-143 expression.

CONCLUSION

CLA and LC, which are considered weight loss supplements, can potentially regulate metabolism and cellular pathways. However, their combination did not show a synergistic effect on weight loss, possibly due to the reduction in miR-27a expression. Further studies are needed to evaluate the effects of combined fat burners on obesity treatment.

The antioxidant and anti-inflammatory activities of caffeine effectively attenuate nonalcoholic steatohepatitis and thioacetamide-induced hepatic injury in male rats

The antioxidant effect of caffeine, associated with its ability to upregulate the nuclear factor-E2-related factor-2 (Nrf2)-signaling pathway, was explored as a possible mechanism for the attenuation of liver damage. Nonalcoholic steatohepatitis (NASH) was induced in rats by the administration of a high-fat, high-sucrose, high-cholesterol diet (HFSCD) for 15 weeks. Liver damage was induced in rats by intraperitoneal administration of thioacetamide (TAA) for six weeks. Caffeine was administered orally at a daily dose of 50 mg/kg body weight during the period of NASH induction to evaluate its ability to prevent disease development. Meanwhile, rats received TAA for three weeks, after which 50 mg/kg caffeine was administered daily for three weeks with TAA to evaluate its capacity to interfere with the progression of hepatic injury. HFSCD administration induced hepatic steatosis, decreased Nrf2 levels, increased oxidative stress, induced the activation of nuclear factor-κB (NF-κB), and elevated proinflammatory cytokine levels, leading to hepatic damage. TAA administration produced similar effects, excluding steatosis. Caffeine increased Nrf2 levels; attenuated oxidative stress markers, including malondialdehyde and 4-hydroxynonenal; restored normal, reduced glutathione levels; and reduced NF-κB activation, inflammatory cytokine levels, and damage. Our findings suggest that caffeine may be useful in the treatment of human liver diseases.

Replacement Flame-Retardant 2-Ethylhexyldiphenyl Phosphate (EHDPP) Disrupts Hepatic Lipidome: Evidence from Human 3D Hepatospheroid Cell Culture

The present study aims to evaluate the effects of repeated exposure to 2-ethylhexyldiphenyl phosphate (EHDPP) on human liver cells. In vitro three-dimensional (3D) hepatospheroid cell culture was utilized to explore the potential mechanisms of EHDPP-mediated metabolic disruption through morphological, transcriptional, and biochemical assays. Lipidomics analysis was performed on the individual hepatospheroids to investigate the effects on intracellular lipid profiles, followed by hepatospheroid morphology, growth, functional parameters, and cytotoxicity evaluation. The possible mechanisms were delineated using the gene-level analysis by assessing the expression of key genes encoding for hepatic lipid metabolism. We revealed that exposure to EHDPP at 1 and 10 μM for 7 days alters the lipid profile of human 3D hepatospheroids. Dysregulation in several lipid classes, including sterol lipids (cholesterol esters), sphingolipids (dihydroceramide, hexosylceramide, ceramide, sphingomyelin), glycerolipids (triglycerides), glycerophospholipids, and fatty acyls, was noted along with alteration in genes including ACAT1, ACAT2, CYP27A1, ABCA1, GPAT2, PNPLA2, PGC1α, and Nrf2. Our study brings a novel insight into the metabolic disrupting effects of EHDPP and demonstrates the utility of hepatospheroids as an in vitro cell culture model complemented with omics technology (e.g., lipidomics) for mechanistic toxicity studies.

Caffeine Inhibits NLRP3 Inflammasome Activation by Downregulating TLR4/MAPK/NF-κB Signaling Pathway in an Experimental NASH Model

Caffeine elicits protective effects against liver diseases, such as NASH; however, its mechanism of action involving the pyrin domain-containing-3 (NLRP3) inflammasome signaling pathway remains to be elucidated. This study aimed to evaluate the effect of caffeine on the NLRP3 inflammasome signaling pathway in a rat model of NASH. NASH was induced by feeding rats a high-fat, -sucrose, and -cholesterol diet (HFSCD) for 15 weeks along with a weekly low dose (400 mg/kg, i.p.) of CCl₄. Caffeine was administered at 50 mg/kg p.o. The effects of HFSCD+CCl₄ and caffeine on the liver were evaluated using biochemical, ultrastructural, histological, and molecular biological approaches. The HFSCD+CCl₄-treated rats showed fat accumulation in the liver, elevated levels of inflammatory mediators, NLRP3 inflammasome activation, antioxidant dysregulation, and liver fibrosis. Caffeine reduced necrosis, cholestasis, oxidative stress, and fibrosis. Caffeine exhibited anti-inflammatory effects by attenuating NLRP3 inflammasome activation. Moreover, caffeine prevented increases in toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) protein levels and mitigated the phosphorylation of mitogen-activated protein kinase (MAPK). Importantly, caffeine prevented the activation of hepatic stellate cells. This study is the first to report that caffeine ameliorates NASH by inhibiting NLRP3 inflammasome activation through the suppression of the TLR4/MAPK/NF-κB signaling pathway.

Comparative and Combined Effects of Epigallocatechin-3-gallate and Caffeine in Reducing Lipid Accumulation in Caenorhabditis elegans

Epigallocatechin-3-gallate (EGCG) and caffeine, two phytochemicals found in a wide range of natural dietary sources, have been reported to have protective effects against hyperlipidemia, a major risk factor for cardiovascular disease. However, their relative efficacy and synergy in lowering lipid level are unclear. This study intended to compare lipid-lowering activity of EGCG and caffeine and to elucidate their joint action using Caenorhabditis elegans (C. elegans) as a model organism. The worms were exposed to EGCG, caffeine or both agents, and lipid accumulation determined by levels of total lipids, triglycerides and cholesterol was monitored. A 3 × 3 factorial design combined with response surface methodology was used to characterize the nature of interactive effects. Total lipids, triglycerides and cholesterol in C. elegans were reduced by either EGCG or caffeine in a dose-dependent manner, with EGCG displaying a stronger lipid-lowering efficacy than caffeine. Overall, the EGCG/caffeine combination for lowering lipids was more effective than either substance alone. Factorial regression models revealed that the combination was antagonistic for total lipid reduction, perhaps due to a "ceiling" effect, and was synergistic for triglyceride-lowering and additive for cholesterol-lowering. Taken together, our work proposes the use of a combination of EGCG and caffeine as an alternative dietary intervention for the prevention of hyperlipidemia, and additionally highlights the suitability of C. elegans model for evaluating lipid-lowering capacity of natural products.

Caffeine mitigates experimental nonalcoholic steatohepatitis and the progression of thioacetamide-induced liver fibrosis by blocking the MAPK and TGF-β/Smad3 signaling pathways

INTRODUCTION AND OBJECTIVES

Caffeine consumption is associated with beneficial effects on hepatic disorders. The objectives of this study were to evaluate the antifibrotic effects of caffeine on experimental nonalcoholic steatohepatitis (NASH) induced with a high-fat, high-sucrose, high-cholesterol diet (HFSCD), as well as to evaluate the ability of caffeine to prevent the progression of experimental liver fibrosis induced by the administration of thioacetamide (TAA) in rats and explore the mechanisms of action.

METHODS

NASH and fibrosis were induced in rats by the administration of an HFSCD for 15 weeks, and liver fibrosis was induced by intraperitoneal administration of 200 mg/kg TAA 3 times per week, for 6 weeks. Caffeine was administered at a dose of 50 mg/kg body weight. The effects of diet, TAA, and caffeine on fibrosis were evaluated by biochemical and histological examinations. The profibrotic pathways were analyzed by western blotting and immunohistochemistry.

RESULTS

Rats exhibited liver fibrosis after HFSCD feeding and the administration of TAA. Caffeine could reduce the hepatic level of collagen and the fibrotic area in the liver. Caffeine prevented the progression of liver fibrosis by decreasing transforming growth factor-beta (TGF-β), connective tissue growth factor (CTGF), and alpha-smooth muscle actin (α-SMA) expression and by inhibiting the activation of mitogen-activated protein kinases (MAPKs) and Smad3 phosphorylation.

CONCLUSIONS

Caffeine attenuates NASH and the progression of liver fibrosis due to its antifibrotic effects and modulating the MAPK and TGF-β pathways. Therefore, caffeine could be a suitable candidate for treating liver diseases associated with fibrosis.

Phytochemical properties and functional characteristics of wild turmeric (Curcuma aromatica) fermented with Rhizopus oligosporus

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Wild turmeric (Curcuma aromatica) was fermented with R. oligosporus.

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Curcuminoid fermented for 5 days and phenolic compound of all fermented wild turmeric increased.

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The l-carnitine content of fermented wild turmeric was newly synthesized.

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The antioxidant activities were enhanced 1.47-fold after fermentation for 3 days.

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Anti-inflammatory, anti-melanogenic, and anti-obesity effects improved with fermentation.

This study investigated the effect of solid-state fermentation of wild turmeric (Curcuma aromatica) with Rhizopus oligosporus, a common fungus found in fermented soy tempeh, on phytochemical and biological properties. Ultra-performance liquid chromatography–tandem mass spectrometry showed that fermented wild turmeric has higher concentrations of curcumin, demethoxycurcumin, bisdemethoxycurcumin, phenolic compounds and total flavonoid-curcuminoid after fermentation for 1-, 3-, and 5-day relative to non-fermented turmeric. The l-carnitine content reached 242 µg g⁻¹ extract after fermentation for 7-day. Wild turmeric had 1.47- and 2.25-fold increases in ORAC and FRAP, respectively, after 3-day fermentation. The inhibitory effects of fermented wild turmeric on lipid accumulation from 3T3-L1 cells, nitric oxide production from lipopolysaccharide-stimulated RAW264.7 murine macrophages, and melanin formation by B16F10 mouse melanoma cells with α-MSH increased 1.08-, 1.44-, and 1.52-fold, respectively, after 3-day fermentation. Based on these results, fermented wild turmeric product can be used as a functional ingredient in the cosmeceutical and nutraceutical industries.

Caffeine as a Factor Influencing the Functioning of the Human Body-Friend or Foe?

Nowadays, caffeine is one of the most commonly consumed substances, which presents in many plants and products. It has both positive and negative effects on the human body, and its activity concerns a variety of systems including the central nervous system, immune system, digestive system, respiratory system, urinary tract, etc. These effects are dependent on quantity, the type of product in which caffeine is contained, and also on the individual differences among people (sex, age, diet etc.). The main aim of this review was to collect, present, and analyze the available information including the latest discoveries on the impact of caffeine on human health and the functioning of human body systems, taking into account the role of caffeine in individual disease entities. We present both the positive and negative sides of caffeine consumption and the healing properties of this purine alkaloid in diseases such as asthma, Parkinson's disease, and others, not forgetting about the negative effects of excess caffeine (e.g., in people with hypertension, children, adolescents, and the elderly). In summary, we can conclude, however, that caffeine has a multi-directional influence on various organs of the human body, and because of its anti-oxidative properties, it was, and still is, an interesting topic for research studies including those aimed at developing new therapeutic strategies.

Anti-Obesity Effects of Soybean Embryo Extract and Enzymatically-Modified Isoquercitrin

Soy isoflavones are bioactive phytoestrogens with known health benefits. Soybean embryo extract (SEE) has been consumed as a source of isoflavones, mainly daidzein, glycitein, and genistein. While previous studies have reported the anti-obesity effects of SEE, this study investigates their molecular mechanisms and the synergistic effects of co-treatment with SEE and enzymatically modified isoquercitrin (EMIQ). SEE upregulated genes involved in lipolysis and brown adipocyte markers and increased mitochondrial content in differentiated C3H10T1/2 adipocytes in vitro. Next, we use a high-fat diet-induced obesity mouse model to determine the anti-obesity effect of SEE. Two weeks of single or combined treatment with SEE and EMIQ significantly reduced body weight gain and improved glucose tolerance. Mechanistically, SEE treatment increased mitochondrial content and upregulated genes involved in lipolysis in adipose tissue through the cAMP/PKA-dependent signaling pathway. These effects required a cytosolic lipase adipose triglyceride lipase (ATGL) expression, confirmed by an adipocyte-specific ATGL knockout mouse study. Collectively, this study demonstrates that SEE exerts anti-obesity effects through the activation of adipose tissue metabolism and exhibits a synergistic effect of co-treatment with EMIQ. These results improve our understanding of the mechanisms underlying the anti-obesity effects of SEE related to adipose tissue metabolism.

Relationship of the Phytochemicals from Coffee and Cocoa By-Products with their Potential to Modulate Biomarkers of Metabolic Syndrome In Vitro

This study aimed to compare the phytochemicals from coffee and cocoa by-products and their relationship with the potential for reducing markers of inflammation, oxidative stress, adipogenesis, and insulin resistance in vitro. We characterized the phytochemical profile of extracts from coffee husk, coffee silverskin, and cocoa shell and evaluated their in vitro biological activity in RAW264.7 macrophages and 3T3-L1 adipocytes. Pearson correlations and principal component regressions were performed to find the contribution of phytochemicals and underlying mechanisms of action. Coffee husk and silverskin extracts were mainly composed of caffeine and chlorogenic acid. Major components in cocoa shell included theobromine and protocatechuic acid. Both coffee and cocoa by-product extracts effectively reduced inflammatory markers in macrophages and adipocytes (NO, PGE2, TNF-α, MCP-1, and IL-6) and the production of reactive oxygen species (21.5-66.4%). Protocatechuic and chlorogenic acids, together with caffeine, were suggested as main contributors against inflammation and oxidative stress. Furthermore, extracts reduced lipid accumulation (4.1-49.1%) in adipocytes by regulating lipolysis and inducing adipocyte browning. Gallic and chlorogenic acids were associated with reduced adipogenesis, and caffeine with adipocyte browning. Extracts from coffee and cocoa by-products also modulated the phosphorylation of insulin receptor signaling pathway and stimulated GLUT-4 translocation (52.4-72.9%), increasing glucose uptake. The insulin-sensitizing potential of the extracts was mainly associated with protocatechuic acid. For the first time, we identified the phytochemicals from coffee and cocoa by-products and offered new insights into their associations with biomarkers of inflammation, oxidative stress, adipogenesis, and insulin resistance in vitro.

Anti-Inflammatory and Anti-Obesity Properties of Food Bioactive Components: Effects on Adipose Tissue

Obesity is an epidemic and costly disease affecting 13% of the adult population worldwide. Obesity is associated with adipose tissue hypertrophy and hyperplasia, as well as pathologic endocrine alterations of adipose tissue including local and chronic systemic low-grade inflammation. Moreover, this inflammation is a risk factor for both metabolic syndrome (MetS) and insulin resistance. Basic and clinical studies demonstrate that foods containing bioactive compounds are capable of preventing both obesity and adipose tissue inflammation, improving obesity-associated MetS in human subjects and animal models of obesity. In this review, we discuss the anti-obesity and anti-inflammatory protective effects of some bioactive polyphenols of plant origin and omega-3 polyunsaturated fatty acids, available for the customers worldwide from commonly used foods and/or as components of commercial food supplements. We review how these bioactive compounds modulate cell signaling including through the nuclear factor-κB, adenosine monophosphate-activated protein kinase, mitogen-activated protein kinase, toll-like receptors, and G-protein coupled receptor 120 intracellular signaling pathways and improve the balance of pro- and anti-inflammatory mediators secreted by adipose tissue and subsequently lower systemic inflammation and risk for metabolic diseases.

Glucagon-induced extracellular cAMP regulates hepatic lipid metabolism

Hormonal signals help to maintain glucose and lipid homeostasis in the liver during the periods of fasting. Glucagon, a pancreas-derived hormone induced by fasting, promotes gluconeogenesis through induction of intracellular cAMP production. Glucagon also stimulates hepatic fatty acid oxidation but the underlying mechanism is poorly characterized. Here we report that following the acute induction of gluconeogenic genes Glucose 6 phosphatase (G6Pase) and Phosphoenolpyruvate carboxykinase (Pepck) expression through cAMP-response element-binding protein (CREB), glucagon triggers a second delayed phase of fatty acid oxidation genes Acyl-coenzyme A oxidase (Aox) and Carnitine palmitoyltransferase 1a (Cpt1a) expression via extracellular cAMP. Increase in extracellular cAMP promotes PPARα activity through direct phosphorylation by AMP-activated protein kinase (AMPK), while inhibition of cAMP efflux greatly attenuates Aox and Cpt1a expression. Importantly, cAMP injection improves lipid homeostasis in fasted mice and obese mice, while inhibition of cAMP efflux deteriorates hepatic steatosis in fasted mice. Collectively, our results demonstrate the vital role of glucagon-stimulated extracellular cAMP in the regulation of hepatic lipid metabolism through AMPK-mediated PPARα activation. Therefore, strategies to improve cAMP efflux could serve as potential new tools to prevent obesity-associated hepatic steatosis.

Combination therapy with catechins and caffeine inhibits fat accumulation in 3T3-L1 cells

Catechins and caffeine, which are green tea components, have a slimming effect; however, the combinational effect of fat metabolism in 3T3-L1 cells remains unclear. In the present study, 3T3-L1 cells were treated with catechins and caffeine in combination, and it was found that combination therapy with catechins and caffeine markedly reduced intracellular fat accumulation, mRNA expression levels of peroxisome proliferator-activated receptor-γ and CCAAT/enhancer-binding protein α in the early stage of cell differentiation were significantly reduced, and mRNA expression of fatty acid synthetase(FAS) andglycerol-3-phosphate dehydrogenase protein expression levels of FAS were downregulated. Noradrenaline-induced lipolysis was enhanced by caffeine, which markedly increased the protein expression of adipose triglyceride lipase and hormone sensitive lipase. These results indicated that combination therapy with catechins and caffeine synergistically inhibited lipid accumulation by regulating the gene and protein expression levels of lipid metabolism-related enzymes. Therefore, catechins and caffeine combination therapy has potential as a functional food that may be used to prevent obesity and lifestyle-associated diseases.

A review on possible therapeutic targets to contain obesity: The role of phytochemicals

The prevalence and severity of obesity has increased markedly in recent decades making it a global public health concern. Since obesity is a potential risk factor in the development of hypertension, type-2 diabetes, cardiovascular diseases, infertility, etc., it is no more viewed as a cosmetic issue. Currently, only a few FDA-approved anti-obesity drugs like Orlistat, Lorcaserin and Phentermine-topiramate are available in the market, but they have considerable side effects. On the other hand, bariatric surgery as an alternative is associated with high risk and expensive. In view of these there is a growing trend towards natural product-based drug intervention as one of the crucial strategies for management of obesity and related ailments. In Asian traditional medicine and Ayurvedic literature a good number of plant species have been used and quoted for possible lipid-lowering and anti-obesity effects; however, many of them have not been evaluated rigorously for a definite recommendation and also lack adequate scientific validation. This review explores and updates on various plant species, their used parts, bioactive components and focuses multiple targets/pathways to contain obesity which may pave the way to develop novel and effective drugs. We also summarised different drugs in use to treat obesity and their current status. Nature is future promise of our wellbeing.

Germinated waxy black rice extract inhibits lipid accumulation with regulation of multiple gene expression in 3T3-L1 adipocytes

The aim of this study was to investigate the anti-obesity effects of germinated waxy black rice (GWBR) extract in 3T3-L1 adipocytes. The inhibitory effect of GWBR extract against adipocyte differentiation was evaluated using Oil Red O staining and glycerol-3-phosphate dehydrogenase (GPDH) assay. GWBR extract inhibited adipocyte differentiation, but was not found to elicit any cytotoxicity. The mRNA levels of adipogenic transcriptional factors such as C/EBP-α and -β, PPAR-γ, and SREBP-1c, as well as adipogenic enzymes, including aP2, LPL, and FAS were significantly downregulated by treatment with GWBR extract compared to untreated control cells. However, mRNA levels of lipolytic genes such as HSL and ATGL, β-oxidation related genes CPT1, and UCP2 involved in thermogenesis were significantly up-regulated by treatment with GWBR extract. These data suggest that GWBR extract may be a potential functional food, and may have pharmacological applications in both the prevention and treatment of obesity.

Soy Isoflavones Regulate Lipid Metabolism through an AKT/mTORC1 Pathway in Diet-Induced Obesity (DIO) Male Rats

The pandemic tendency of obesity and its strong association with serious co-morbidities have elicited interest in the underlying mechanisms of these pathologies. Lipid homeostasis, closely involved in obesity, has been reported to be regulated by multiple pathways. mTORC1 is emerging as a critical regulator of lipid metabolism. Here, we describe that the consumption of soy isoflavones, with a structural similarity to that of estradiol, could mitigate obesity through an AKT/mTORC1 pathway. Fed with soy isoflavones, the diet-induced obesity (DIO) male rats exhibited decreased body weight, accompanied with suppressed lipogenesis and adipogenesis, as well as enhanced lipolysis and β‑oxidation. The phosphorylation of AKT and S6 were decreased after soy isoflavone treatment in vivo and in vitro, suggesting an inhibition effect of soy isoflavones on mTORC1 activity. Our study reveals a potential mechanism of soy isoflavones regulating lipid homeostasis, which will be important for obesity treatment.

Effects of amino acid derivatives on physical, mental, and physiological activities

Nutritional ergogenic aids have been in use for a long time to enhance exercise and sports performance. Dietary components that exhibit ergogenic activity are numerous and their consumption is common and popular among athletes. They often come under scrutiny by legal authorities for their claimed benefits and safety concerns. Amino acid derivatives are propagated as being effective aids to enhance physical and mental performance in many ways, even though studies have pointed out that individuals who are deficient are more likely to benefit from dietary supplementation of amino acid derivatives than normal humans. In this review, some of the most common and widely used amino acids derivatives in sports and athletics namely creatine, tyrosine, carnitine, HMB, and taurine have been discussed for their effects on exercise performance, mental activity as well as body strength and composition. Creatine, carnitine, HMB, and taurine are reported to delay the onset of fatigue, improve exercise performance, and body strength. HMB helps in increasing fat-free mass and reduce exercise induced muscle injury. Taurine has been found to reduce oxidative stress during exercise and also act as an antihypertensive agent. Although, studies have not been able to find any favorable effect of tyrosine administration on exercise performance, it has been proved to be very effective in fighting stress, improving mood and cognitive performance particularly in sleep-deprived subjects. While available data from published studies and findings are equivocal about the efficacy of creatine, tyrosine, and HMB, more comprehensive researches on carnitine and taurine are necessary to provide evidence for the theoretical basis of their ergogenic role in nutritional modification and supplementation.

Oral intake of a combination of glucosyl hesperidin and caffeine elicits an anti-obesity effect in healthy, moderately obese subjects: a randomized double-blind placebo-controlled trial

Background

We have previously shown that a combination of glucosyl hesperidin (G-hesperidin) plus caffeine reduces accumulation of body fat, whereas G-hesperidin or caffeine alone shows little effect on high-fat diet-induced obesity in mice. The aim of this study is to evaluate the anti-obesity effect of G-hesperidin plus caffeine on body fat and serum TG in healthy subjects with moderately high body mass index (BMI) and serum TG. Since we considered that there are individual differences in caffeine sensitivity, we conducted dose-finding study of caffeine combined with G-hesperidin.

Methods

Seventy-five healthy subjects with moderately high BMI (24–30 kg/m²) and serum TG (100–250 mg/dl) were divided and assigned to 12-week intervention with daily intakes of 500 mg of G-hesperidin with or without 25, 50, or 75 mg of caffeine, or placebo in a randomized double-blind placebo-controlled design .

Results

After intervention, decreases in abdominal fat area (AFA), especially subcutaneous fat area (SFA), were significantly greater in the G-hesperidin with 50-mg caffeine group (AFA:-8.4 ± 21.9 v.s. 16.3 ± 34.1 cm²; p < 0.05, SFA: -9.3 ± 17.1 v.s. 11.2 ± 18.3 cm²; p < 0.01) and in the G-hesperidin with 75-mg caffeine group (AFA:-17.0 ± 31.4 v.s. 16.3 ± 34.1 cm²; p < 0.01, SFA: -12.4 ± 18.7 v.s. 11.2 ± 18.3 cm²; p < 0.01) than in the placebo group. Fat-decreasing effects of G-hesperidin were enhanced dose-dependently by caffeine addition. BMI decreases were significantly greater in the G-hesperidin with 75-mg caffeine group than in the placebo group (-0.56 ± 0.74 v.s. -0.02 ± 0.58 kg/m²; p < 0.05). G-hesperidin with/without caffeine had no effect on serum TG (p > 0.05 v.s. placebo).

Conclusions

These data suggested that a combination of 500-mg G-hesperidin with 50- or 75-mg caffeine may be useful for the prevention or treatment of obesity.

Trial registration

UMIN Clinical Trials Registry 000019241.

Efeito da suplementação aguda com cafeína na resposta bioquímica durante exercício de endurance em ratos

RESUMO Introdução: A cafeína é atualmente a substância mais consumida no mundo, e associada ao exercício físico, vem trazendo importantes ganhos no desempenho. Objetivo: Investigar efeitos bioquímicos da suple-mentação aguda de cafeína após um exercício de endurance em ratos Wistar. Métodos: Foram utilizados 27 ratos Wistar machos, pesando 357 ± 73 g, distribuídos de forma aleatória em três grupos: 1) Controle (sem suplementação e exercício); 2) Salina (salina + exercício); 3) Cafeína (6 mg/Kg de cafeína + exercício). As suple-mentações foram administradas com antecedência de 50 minutos da natação com duração de 60 minutos. Logo após a natação, os animais foram sacrificados para coleta de sangue e biópsia de tecido hepático e muscular. Foram analisados os níveis de glicose sanguínea, triglicerídeos, lactato sérico e concentrações de glicogênio hepático e muscular. Todos os resultados foram representados como média ± EPM. Para a análise estatística foi usado o teste ANOVA one way, sendo considerada diferença estatística somente para P<0,05. Resultados: O glicogênio muscular e o lactato não diferiram entre os grupos. A cafeína preservou os níveis de glicose sanguínea e glicogênio hepático (P<0,05). A cafeína elevou os níveis de glicerol plasmático em 31,2% (P<0,05) quando comparado ao grupo exercitado sem suplementação. Conclusão: O estudo reporta que o uso da cafeína pré-exercício promove alterações bioquímicas que podem melhorar a eficiência metabólica durante o exercício de endurance.

Improvement of Nonalcoholic Fatty Liver Disease With Carnitine-Orotate Complex in Type 2 Diabetes (CORONA): A Randomized Controlled Trial

OBJECTIVE

We aimed to evaluate the effects of carnitine-orotate complex in patients with nonalcoholic fatty liver disease (NAFLD) and diabetes.

RESEARCH DESIGN AND METHODS

Eight hospitals in Korea participated in this randomized, controlled, double-blind trial of patients with diabetes and NAFLD. Seventy-eight patients were randomly assigned in a 1:1 ratio to receive carnitine-orotate complex (824 mg, three times daily) or matching placebo. The primary study outcome was decline in alanine aminotransferase (ALT) to the normal range. Secondary study outcomes were change in ALT, radiological hepatic steatosis, parameters for anthropometry, liver function, lipid profiles, and glycemic control. Hepatic steatosis was assessed using Hounsfield units on noncontrast computed tomography (CT) imaging with hepatic attenuation.

RESULTS

After 12 weeks of treatment, compared with placebo group, carnitine-orotate complex-treated participants had a significantly higher rate of normalization of serum ALT level (17.9% vs. 89.7%, P < 0.001). On hepatic CT analysis, participants treated with carnitine-orotate complex showed an increased liver attenuation index (0.74 ± 8.05 vs. 6.21 ± 8.96, P < 0.008). A significant decrease in HbA1c was observed in the carnitine-orotate complex group (-0.33 ± 0.82% [-3.6 ± 9.0 mmol/mol], P = 0.007), but no significant change was seen in the placebo group.

CONCLUSIONS

Treatment with carnitine-orotate complex improves serum ALT and may improve hepatic steatosis as assessed by CT in patients with diabetes and NAFLD. Further studies using more advanced magnetic resonance imaging and liver histology as an end point are needed to assess its efficacy in NAFLD.

A combination of glucosyl hesperidin and caffeine exhibits an anti-obesity effect by inhibition of hepatic lipogenesis in mice

To develop an anti-obesity agent, we examined the combination effect of glucosyl hesperidin (G-hesperidin) and caffeine on obesity in mice. High-fat diet-induced obese KK mice were fed a low-fat diet with or without G-hesperidin, caffeine, or their combination for 2 weeks. Decreases in body weight and significantly lower adipose tissue weight were observed in the combination-fed mice but not in the G-hesperidin-fed or caffeine-fed mice. DNA microarray analysis of mouse liver suggested that the feeding of G-hesperidin + caffeine was associated with lower lipogenesis. Therefore, we examined the anti-lipogenic effect of G-hesperidin + caffeine in fasted-refed KK mice. Hepatic triglyceride levels were significantly lower in the mice fed G-hesperidin + caffeine during the refeeding period but not in the mice fed each alone. In addition, hepatic expressions of genes related to lipogenesis, such as sterol regulatory element-binding protein-1c or fatty acid synthase, were significantly lower in the mice fed G-hesperidin + caffeine compared with that in the control mice. These results suggested that G-hesperidin + caffeine is effective for controlling obesity partly by the inhibition of hepatic lipogenesis.

Sulfonylurea induction of caffeine-enhanced insulin secretion and reduction of glycemic levels in diabetic rats

CONTEXT

Caffeine can stimulate insulin secretion by attenuating hyperglycemia in diabetes models with significant reduction of pancreatic functional β cells. Knowledge of these mechanisms could contribute to new strategies for treating diabetes.

OBJECTIVE

This study evaluated the effects of caffeine and physical exercise on glycemic and insulin responses in diabetic rats.

MATERIALS AND METHODS

The diabetes model was induced by intraperitoneal administration of 60 mg/kg of streptozotocin (STZ). Animals were divided into six groups: control, caffeine, STZ control, STZ caffeine, STZ sulfonylurea, and STZ caffeine + sulfonylurea. Acutely, control animals received 6 mg of caffeine and 10 mg/kg sulfonylurea or 10 mg/kg saline. Animals were sacrificed after physical exercise; blood samples were collected for glucose, glycerol, lactate, and insulin analyses. Cardiovascular responses were recorded before and after treatments. A one-way ANOVA and the post hoc Student-Newman-Keuls test were used to analyze statistical differences between treatments (p < 0.05).

RESULTS

About 6 mg/kg of caffeine did not alter cardiovascular responses, but promoted blood glucose reduction after 60 min of exercise when compared to animals in the control groups (387-187 mg/dL; p < 0.05). Insulin levels increased significantly (0.6-10 µU/mL; p < 0.05) in rats that received acute caffeine treatment associated with sulfonylurea compared to rats in the other groups.

DISCUSSION AND CONCLUSION

Acute caffeine intake with exercise can increase glucose uptake enhancing insulin secretion stimulated by sulfonylurea in β cells-deficient pancreas. The results indicate the potential use of caffeine as a strategy for glycemic and insulin control in diabetes.

Elevated sensitivity of macrosteatotic hepatocytes to hypoxia/reoxygenation stress is reversed by a novel defatting protocol

Macrosteatotic livers exhibit elevated intrahepatic triglyceride (TG) levels in the form of large lipid droplets (LDs), reduced adenosine triphosphate (ATP) levels, and elevated reactive oxygen species (ROS) levels, and this contributes to their elevated sensitivity to ischemia/reperfusion injury during transplantation. Reducing macrosteatosis in living donors through dieting has been shown to improve transplant outcomes. Accomplishing the same feat for deceased donor grafts would require ex vivo exposure to potent defatting agents. Here we used a rat hepatocyte culture system exhibiting a macrosteatotic LD morphology, elevated TG levels, and an elevated sensitivity to hypoxia/reoxygenation (H/R) to test for such agents and ameliorate H/R sensitivity. Macrosteatotic hepatocyte preconditioning for 48 hours with a defatting cocktail that was previously developed to promote TG catabolism reduced the number of macrosteatotic LDs and intracellular TG levels by 82% and 27%, respectively, but it did not ameliorate sensitivity to H/R. Supplementation of this cocktail with l-carnitine, together with hyperoxic exposure, yielded a similar reduction in the number of macrosteatotic LDs and a 57% reduction in intrahepatic TG storage, likely by increasing the supply of acetyl coenzyme A to mitochondria, as indicated by a 70% increase in ketone body secretion. Furthermore, this treatment reduced ROS levels by 32%, increased ATP levels by 27% (to levels near those of lean controls), and completely abolished H/R sensitivity as indicated by approximately 85% viability after H/R and the reduction of cytosolic lactate dehydrogenase release to levels seen in lean controls. Cultures maintained for 48 hours after H/R were approximately 83% viable and exhibited superior urea secretion and bile canalicular transport in comparison with untreated macrosteatotic cultures. In conclusion, these findings show that the elevated sensitivity of macrosteatotic hepatocytes to H/R can be overcome by defatting agents, and they suggest a possible route for the recovery of discarded macrosteatotic grafts.

Effect of carnitine-orotate complex on glucose metabolism and fatty liver: a double-blind, placebo-controlled study

BACKGROUND AND AIM

Effective medicines have not been introduced for insulin resistance-related fatty liver. The efficacy and safety of treatment between a combination of metformin and carnitine-orotate complex and metformin alone in a 12-week, double-blind, randomized, placebo-controlled study on drug-naïve patients with impaired glucose metabolism and fatty liver were compared.

METHODS

Fifty-two patients with fasting glucose 100-240 mg/dL or glycosylated hemoglobin (HbA1c) ≥ 6.0% and alanine aminotransferase (ALT) 40-250 IU/L were randomized to receive metformin (250 mg t.i.d.), or metformin (250 mg t.i.d.) and carnitine-orotate complex (300 mg t.i.d.) for 12 weeks (n = 26 per group). The primary end-point was a change from baseline ALT level. Secondary end-points were changes in fasting glucose, HbA1c, aspartate aminotransferase levels, mitochondrial DNA (mtDNA) copy number in the peripheral blood, and urinary output of 8-hydroxy-2'-deoxyguanosine, a marker of oxidative stress.

RESULTS

The combined treatment reduced ALT level significantly more than metformin alone (-51.5 ± 33.2 IU/L vs -16.7 ± 31.3 IU/L, P = 0.001). The HbA1c levels also decreased significantly in both groups but there was no significant difference between them (-0.9% ± 1.0% vs -0.7% ± 0.9%). Treatment with the complex decreased the urinary 8-hydroxy-2'-deoxyguanosine level and increased mtDNA copy number significantly compared with metformin alone (both P < 0.05). No severe adverse events were observed.

CONCLUSION

A 12-week treatment with metformin and carnitine-orotate complex significantly improved liver function enzyme levels. This was associated with changes in oxidative stress and mtDNA copy number compared with metformin alone in patients with impaired glucose metabolism and fatty liver (clinical trial number: KCT0000193).

Nutraceuticals and regulation of adipocyte life: premises or promises

Obesity is the actual worldwide health threat, that is associated with an increased number of metabolic disorders and diseases. Following the traditional hypothesis stating that in obesity hypertrophic adipocytes trigger the adipose tissue hyperplasia, strategies to treat obesity have increased fat researches of the molecular processes that achieve adipocyte enlargement and formation that finally increase body fat mass. Moreover, a new cell type was recently identified, the "brite" adipocyte that presents a unique gene expression profile of compared to both brown and white adipocytes. Therapies against obesity, targeting these cells and their pathways, would include the induction of lipolysis and apoptosis or the inhibition of differentiation and adipogenesis. However, it should be noted that both the increase of adipocyte size and number take place in association with positive energy balance. According to the adipose tissue expansion hypothesis, adipogenesis could be related with improved metabolic health of obese people, taking back the adipose mass to a traditionally site of lipid storage. Furthermore, new perspectives in fat biology suggest that the conversion of white-to-brown adipocytes and their metabolism could be exploited for the development of therapeutic approaches against obesity-associated diseases and for the regulation of energy balance. Drugs currently available to treat obesity generally have unpleasant side effects. A novel promising approach is the usage of dietary supplements and plant products that could interfere on the life cycle of adipocyte. Here, various dietary bioactive compounds that target different stages of adipocyte life cycle and molecular and metabolic pathways are reviewed.

Regulation of adipocyte lipolysis

In adipocytes the hydrolysis of TAG to produce fatty acids and glycerol under fasting conditions or times of elevated energy demands is tightly regulated by neuroendocrine signals, resulting in the activation of lipolytic enzymes. Among the classic regulators of lipolysis, adrenergic stimulation and the insulin-mediated control of lipid mobilisation are the best known. Initially, hormone-sensitive lipase (HSL) was thought to be the rate-limiting enzyme of the first lipolytic step, while we now know that adipocyte TAG lipase is the key enzyme for lipolysis initiation. Pivotal, previously unsuspected components have also been identified at the protective interface of the lipid droplet surface and in the signalling pathways that control lipolysis. Perilipin, comparative gene identification-58 (CGI-58) and other proteins of the lipid droplet surface are currently known to be key regulators of the lipolytic machinery, protecting or exposing the TAG core of the droplet to lipases. The neuroendocrine control of lipolysis is prototypically exerted by catecholaminergic stimulation and insulin-induced suppression, both of which affect cyclic AMP levels and hence the protein kinase A-mediated phosphorylation of HSL and perilipin. Interestingly, in recent decades adipose tissue has been shown to secrete a large number of adipokines, which exert direct effects on lipolysis, while adipocytes reportedly express a wide range of receptors for signals involved in lipid mobilisation. Recently recognised mediators of lipolysis include some adipokines, structural membrane proteins, atrial natriuretic peptides, AMP-activated protein kinase and mitogen-activated protein kinase. Lipolysis needs to be reanalysed from the broader perspective of its specific physiological or pathological context since basal or stimulated lipolytic rates occur under diverse conditions and by different mechanisms.

Caffeine stimulates hepatic lipid metabolism by the autophagy-lysosomal pathway in mice

Caffeine is one of the world's most consumed drugs. Recently, several studies showed that its consumption is associated with lower risk for nonalcoholic fatty liver disease (NAFLD), an obesity-related condition that recently has become the major cause of liver disease worldwide. Although caffeine is known to stimulate hepatic fat oxidation, its mechanism of action on lipid metabolism is still not clear. Here, we show that caffeine surprisingly is a potent stimulator of hepatic autophagic flux. Using genetic, pharmacological, and metabolomic approaches, we demonstrate that caffeine reduces intrahepatic lipid content and stimulates β-oxidation in hepatic cells and liver by an autophagy-lysosomal pathway. Furthermore, caffeine-induced autophagy involved down-regulation of mammalian target of rapamycin signaling and alteration in hepatic amino acids and sphingolipid levels. In mice fed a high-fat diet, caffeine markedly reduces hepatosteatosis and concomitantly increases autophagy and lipid uptake in lysosomes.

CONCLUSION

These results provide novel insight into caffeine's lipolytic actions through autophagy in mammalian liver and its potential beneficial effects in NAFLD.

Caffeine attenuates lipid accumulation via activation of AMP-activated protein kinase signaling pathway in HepG2 cells

The main purpose of this study is to examine the effect of caffeine on lipid accumulation in human hepatoma HepG2 cells. Significant decreases in the accumulation of hepatic lipids, such as triglyceride (TG), and cholesterol were observed when HepG2 cells were treated with caffeine as indicated. Caffeine decreased the mRNA level of lipogenesis-associated genes (SREBP1c, SREBP2, FAS, SCD1, HMGR and LDLR). In contrast, mRNA level of CD36, which is responsible for lipid uptake and catabolism, was increased. Next, the effect of caffeine on AMP-activated protein kinase (AMPK) signaling pathway was examined. Phosphorylation of AMPK and acetyl-CoA carboxylase were evidently increased when the cells were treated with caffeine as indicated for 24 h. These effects were all reversed in the presence of compound C, an AMPK inhibitor. In summary, these data indicate that caffeine effectively depleted TG and cholesterol levels by inhibition of lipogenesis and stimulation of lipolysis through modulating AMPK-SREBP signaling pathways. [BMB Reports 2013; 46(4): 207-212]

Kefir inhibits 3T3-L1 adipocyte differentiation through down-regulation of adipogenic transcription factor expression

BACKGROUND

Kefir, a traditional fermented milk composed of microbial symbionts, is reported to have various health benefits such as anti-tumour, anti-inflammatory, anti-neoplastic and pro-digestive effects. In this study, to elucidate the effects of kefir on adipocyte differentiation and lipid accumulation, three fractions were prepared from kefir culture broth. The inhibitory effects of kefir liquid culture broth fraction (Fr-1), soluble fraction (Fr-2) and insoluble fraction (Fr-3), prepared by sonication of kefir solid culture broth, on adipocyte differentiation in 3T3-L1 preadipocytes were examined.

RESULTS

Fr-3 (0.1 mg mL(-1)) significantly decreased lipid accumulation and glycerol-3-phosphate dehydrogenase (GPDH) activity by 60 and 68% respectively without affecting cell viability. In addition, Fr-3 treatment down-regulated the mRNA expression of adipogenic transcription factors including C/EBPα (32%), PPARγ (46%) and SREBP-1c (34%) during adipocyte differentiation compared with untreated control cells. The mRNA expression of adipocyte-specific genes (aP2, FAS and ACC) was also clearly decreased.

CONCLUSION

The results suggest that the insoluble fraction of kefir (Fr-3) mediates anti-adipogenic effects through the inhibition of adipocyte differentiation, partly via suppression of the C/EBPα-, SREBP-1c- and PPARγ-dependent pathways.

Liver defatting: an alternative approach to enable steatotic liver transplantation

Macrovesicular steatosis in greater than 30% of hepatocytes is a significant risk factor for primary graft nonfunction due to increased sensitivity to ischemia reperfusion (I/R) injury. The growing prevalence of hepatic steatosis due to the obesity epidemic, in conjunction with an aging population, may negatively impact the availability of suitable deceased liver donors. Some have suggested that metabolic interventions could decrease the fat content of liver grafts prior to transplantation. This concept has been successfully tested through nutritional supplementation in a few living donors. Utilization of deceased donor livers, however, requires defatting of explanted organs. Animal studies suggest that this can be accomplished by ex vivo warm perfusion in a time scale of a few hours. We estimate that this approach could significantly boost the size of the donor pool by increasing the utilization of steatotic livers. Here we review current knowledge on the mechanisms whereby excessive lipid storage and macrosteatosis exacerbate hepatic I/R injury, and possible approaches to address this problem, including ex vivo perfusion methods as well as metabolically induced defatting. We also discuss the challenges ahead that need to be addressed for clinical implementation.

Caffeine dose-dependently induces thermogenesis but restores ATP in HepG2 cells in culture

Caffeine has been hypothesised as a thermogenic agent that might help to maintain a healthy body weight. Since very little is known about its actions on cellular energy metabolism, we investigated the effect of caffeine on mitochondrial oxidative phosphorylation, cellular energy supply and thermogenesis in HepG2 cells, and studied its action on fatty acid uptake and lipid accumulation in 3T3-L1 adipocytes at concentrations ranging from 30-1500 μM. In HepG2 cells, caffeine induced a depolarisation of the inner mitochondrial membrane, a feature of mitochondrial thermogenesis, both directly and after 24 h incubation. Increased concentrations of uncoupling protein-2 (UCP-2) also indicated a thermogenic activity of caffeine. Energy generating pathways, such as mitochondrial respiration, fatty acid oxidation and anaerobic lactate production, were attenuated by caffeine treatment. Nevertheless, HepG2 cells demonstrated a higher energy charge potential after exposure to caffeine that might result from energy restoration through attenuation of energy consuming pathways, as typically found in hibernating animals. In 3T3-L1 cells, in contrast, caffeine increased fatty acid uptake, but did not affect lipid accumulation. We provide evidence that caffeine stimulates thermogenesis but concomitantly causes energy restoration that may compensate enhanced energy expenditure.

The anti-obesity effect of Lethariella cladonioides in 3T3-L1 cells and obese mice

The aim of this study was to investigate whether a water extract of L. cladonioides (LC) has an anti-obesity effect in 3T3-L1 cells and obese mice. Treatment of differentiated 3T3-L1 adipocytes with LC caused a significant increase in glycerol release and reduced the protein expression of the adipogenic transcription factors, PPARγ and C/EBPα. In an animal model, obese mice were artificially induced by a high fat diet for 10 weeks. Experimental groups were treated with LC (100 mg/kg/day) by gavage for the next 10 weeks. At the end of experiment, the body weight of the LC group mice was reduced by 14.2% compared to the high fat diet (HFD) group. The treatment also decreased liver (31.0%), epididymal (18.0%) and retroperitoneal (19.3%) adipose tissue, and kidney (6.7%) weights, respectively, compared with those of the HFD group. LC prevented diet-induced increases in the serum level of TC (22.6%), TG (11.6%), and glucose (35.0%), respectively, compared with the HFD group. However, the HDL-C level was higher in the LC group (26.1%) than the HFD group. The results of this study thus suggest that LC suppressed lipid accumulation and expression of adipogenic transcription factors, and increased the amount of glycerol release. LC also indicated an anti-obese and anti-hyperlipidemic effect.

Prevention of free fatty acid-induced hepatic lipotoxicity by carnitine via reversal of mitochondrial dysfunction

BACKGROUND

Mitochondria are the main sites for fatty acid oxidation and play a central role in lipotoxicity and nonalcoholic steatohepatitis.

AIMS

We investigated whether carnitine prevents free fatty acid (FFA)-induced lipotoxicity in vitro and in vivo.

METHODS

HepG2 cells were incubated with FFA, along with carnitine and carnitine complexes. Mitochondrial β-oxidation, transmembrane potential, intracellular ATP levels and changes in mitochondrial copy number and morphology were analysed. Otsuka Long-Evans Tokushima Fatty and Long-Evans Tokushima Otsuka rats were segregated into three experimental groups and fed for 8 weeks with (i) normal chow, (ii) a methionine choline-deficient (MCD) diet or (iii) an L-carnitine-supplemented MCD diet.

RESULTS

Carnitine prevented FFA-induced apoptosis (16% vs. 3%, P < 0.05). FFA treatment resulted in swollen mitochondria with increased inner matrix density and loss of cristae. However, mitochondria co-treated with carnitine had normal ultrastructure. The mitochondrial DNA copy number was higher in the carnitine treatment group than in the palmitic acid treatment group (375 vs. 221 copies, P < 0.05). The carnitine group showed higher mitochondrial β-oxidation than did the control and palmitic acid treatment groups (597 vs. 432 and 395 ccpm, P < 0.05). Carnitine treatment increased the mRNA expression of carnitine palmitoyltransferase 1A and peroxisome proliferator-activated receptor-γ, and carnitine-lipoic acid further augmented the mRNA expression. In the in vivo model, carnitine-treated rats showed lower alanine transaminase levels and lesser lobular inflammation than did the MCD-treated rats.

CONCLUSIONS

Carnitine and carnitine-lipoic acid prevent lipotoxicity by increasing mitochondrial β-oxidation and reducing intracellular oxidative stress.

Improvement of high-fat diet-induced obesity by a mixture of red grape extract, soy isoflavone and L-carnitine: implications in cardiovascular and non-alcoholic fatty liver diseases

In the present study, we examined the effect of a mixture of dietary components, including red grape extract, soy isoflavone and L-carnitine (RISC), on obesity. RISC substantially inhibited high-fat diet (HFD)-induced increase in body weight in a dose-dependent manner in C57BL/6 mice. The amount of subcutaneous and mesenteric fat was also significantly decreased by RISC treatment in HFD-fed C57BL/6 mice, whereas epididymal fat was not affected. Moreover, HFD-induced plasma leptin levels were down-regulated by RISC treatment. In these mice, RISC treatment significantly increased the plasma level of high density lipoprotein cholesterol without affecting the level of low density lipoprotein cholesterol and triglycerides. In addition, HFD-induced increase in liver weight and lipid accumulation in liver was significantly suppressed by RISC treatment in C57BL/6mice. Plasma level of glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase was also inhibited by RISC treatment. These results demonstrate that RISC suppresses HFD-induced obesity and suggest that RISC supplementation might be a promising adjuvant therapy for the treatment of obesity and its complications, such as cardiovascular and non-alcoholic fatty liver diseases.

Caffeine induction of sulfotransferases in rat liver and intestine

Sulfotransferases (SULTs) are important phase II drug-metabolizing enzymes. Regulation of SULTs by hormones and other endogenous molecules is relatively well understood, while xenobiotic induction of SULTs is not well studied. Caffeine is one of the most widely consumed psychoactive substances. However, SULT regulation by caffeine has not been reported. In this report, male and female rats were treated with different oral doses of caffeine (2, 10, 50 mg kg⁻¹ per day) for 7 days. Western blot and real-time RT-PCR were used to investigate the changes in SULT protein and mRNA expression following the caffeine treatment. Caffeine induced both rat aryl sulfotransferase (rSULT1A1, AST-IV) and rat hydroxysteroid sulfotransferase (rSULT2A1, STa) in the liver and intestine of female rats in a dose-dependent manner. Caffeine induction of rSULT1A1 and rSULT2A1 in the female rat intestine was much stronger than that in the liver. Although caffeine induced rSULT1A1 significantly in the male rat liver, it did not significantly induce rSULT2A1. In male rat intestine, caffeine significantly induced rSULT2A1. The different SULTs induction patterns in male and female rats suggest that the regulation of rat SULTs by caffeine may be affected by different hormone secretion patterns and levels. Our results suggest that consumption of caffeine can induce drug metabolizing SULTs in drug detoxification tissues.

A combination of grape extract, green tea extract and L-carnitine improves high-fat diet-induced obesity, hyperlipidemia and non-alcoholic fatty liver disease in mice

To develop a therapeutic agent for obesity-related metabolic disorders, a mixture of dietary components was prepared, including grape extract, green tea extract and l-carnitine (RGTC), and its effects on obesity, hyperlipidemia and non-alcoholic fatty liver disease examined. The RGTC dramatically inhibited the high-fat diet (HFD)-induced increase in body weight and fat in C57BL/6 mice, whereas food consumption was not affected by RGTC treatment. The RGTC also concentration-dependently suppressed the HFD-induced increase in plasma lipids, such as low-density lipoprotein cholesterol and triglycerides. In addition, increases in liver weight and liver steatosis were returned to normal by RGTC treatment in HFD-fed C57BL/6 mice. The plasma levels of glutamic-oxaloacetic transaminase and glutamic-pyruvic transaminase were also significantly down-regulated by RGTC treatment. These results suggest that RGTC suppressed HFD-induced obesity, hyperlipidemia and non-alcoholic fatty liver disease, suggesting that RGTC supplementation might be a promising adjuvant therapy for the treatment of these metabolic disorders.

Acute and subchronic toxicity of FCD, a soybean extract combined with L-carnitine, in Sprague-Dawley rats

Soy products are primarily composed of proteins, phytochemicals such as isoflavones, soy lipids, and carbohydrates. Recently, soy isoflavones with L-carnitine were reported to exhibit anti-obesity effects in mice. FCD, a combination of soybean extract and L-carnitine, is a newly developed food substance. As a part of its safety assessment, acute and 13-week subchronic toxicity studies were performed in a total of 100 Sprague-Dawley (SD) rats. In the acute study, a single limit dose of 2000 mg/kg was orally administered to five male and five female rats. No adverse effects or mortality was observed during a 14-day period or upon gross pathological examination. In the subchronic study, FCD was orally administered in daily doses of 500, 1000, and 2000 mg/kg for 13 weeks, resulting in no mortality, and no changes in hematological and serum biochemistry parameters, gross pathology or histopathology. However, body weights of females were significantly decreased 10 weeks after treatment at an average of 2000 mg/kg. In addition, a slight decrease in mean food and water consumption was observed at the same dose level for 13 weeks. Therefore, the no-observed-adverse-effect-level (NOAEL) of FCD was considered to be 2000 mg/kg for male and 1000 mg/kg for female SD rats.

Lotus leaf extract and L-carnitine influence different processes during the adipocyte life cycle

Background

The cellular and molecular mechanisms of adipose tissue biology have been studied extensively over the last two decades. Adipose tissue growth involves both an increase in fat cell size and the formation of mature adipocytes from precursor cells. To investigate how natural substances influence these two processes, we examined the effects of lotus leaf extract (Nelumbo nucifera-extract solution obtained from Silab, France) and L-carnitine on human preadipocytes and adipocytes.

Methods

For our in vitro studies, we used a lotus leaf extract solution alone or in combination with L-carnitine. Utilizing cultured human preadipocytes, we investigated lotus leaf extract solution-induced inhibition of triglyceride incorporation during adipogenesis and possible effects on cell viability. Studies on human adipocytes were performed aiming to elucidate the efficacy of lotus leaf extract solution to stimulate lipolytic activity. To further characterize lotus leaf extract solution-mediated effects, we determined the expression of the transcription factor adipocyte determination and differentiation factor 1 (ADD1/SREBP-1c) on the RNA- and protein level utilizing qRT-PCR and immunofluorescence analysis. Additionally, the effect of L-carnitine on beta-oxidation was analyzed using human preadipocytes and mature adipocytes. Finally, we investigated additive effects of a combination of lotus leaf extract solution and L-carnitine on triglyceride accumulation during preadipocyte/adipocyte differentiation.

Results

Our data showed that incubation of preadipocytes with lotus leaf extract solution significantly decreased triglyceride accumulation during adipogenesis without affecting cell viability. Compared to controls, adipocytes incubated with lotus leaf extract solution exhibited a significant increase in lipolysis-activity. Moreover, cell populations cultivated in the presence of lotus leaf extract solution showed a decrease in adipocyte differentiation capacity as indicated by a decrease in the ADD1/SREBP-1c signal. Importantly, our results demonstrated that a combination of lotus leaf extract solution and L-carnitine reduced triglyceride accumulation to a greater extent compared to incubation with either substance alone.

Conclusions

Overall, our data demonstrate that a combination of lotus leaf extract and L-carnitine reduced triglyceride accumulation in human (pre)adipocytes by affecting different processes during the adipocyte life cycle. For this reason, this combination might represent a treatment option for obesity-related diseases.

Chronic consumption of fructose rich soft drinks alters tissue lipids of rats

BACKGROUND

Fructose-based diets are apparently related to the occurrence of several metabolic dysfunctions, but the effects of the consumption of high amounts of fructose on body tissues have not been well described. The aim of this study was to analyze the general characteristics and the lipid content of different tissues of rats after chronic ingestion of a fructose rich soft drink.

METHODS

Forty-five Wistar rats were used. The rats were divided into three groups (n = 15) and allowed to consume water (C), light Coca Cola (R) (L) or regular Coca Cola(R) (R) as the sole source of liquids for eight weeks.

RESULTS

The R group presented significantly higher daily liquid intake and significantly lower food intake than the C and L groups. Moreover, relative to the C and L groups, the R group showed higher triglyceride concentrations in the serum and liver. However, the L group animals presented lower values of serum triglycerides and cholesterol than controls.

CONCLUSIONS

Based on the results, it can be concluded that daily ingestion of a large amount of fructose- rich soft drink resulted in unfavorable alterations to the lipid profile of the rats.

Anti-metabolic syndrome effects of adenosine ingestion in stroke-prone spontaneously hypertensive rats fed a high-fat diet

We have demonstrated previously that both acute and chronic oral administration of adenosine have novel functions such as anti-hypertensive effects and improved hyperlipidaemia in stroke-prone spontaneously hypertensive rats (SHRSP) fed a normal diet. The purpose of the present study was to investigate the effect of adenosine administration on metabolic syndrome-related parameters in SHRSP fed a high-fat diet. Six-week-old rats were divided into three groups, and were administered either water (control) or adenosine (10 or 100 mg/l) for 8 weeks. During this period, the rats had free access to a high-fat diet based on AIN-93M. The results showed that hypertension, plasma lipid, NO, insulin, glucose and urinary 8-hydroxy-2'-deoxyguanosine levels improved significantly in both adenosine groups. The mRNA expression levels of genes involved in anti-oxidative activity and adenosine receptors were also altered in the adenosine groups. Administration of adenosine also increased plasma adiponectin levels, accompanied by upregulation of mRNA expression level of adiponectin and adiponectin receptor 1 in perirenal fat and adiponectin receptor 2 in the liver. In conclusion, oral administration of adenosine is effective for improving metabolic syndrome-related parameters in SHRSP, and accordingly it may prevent the progression of the metabolic syndrome.

Adenosine signaling contributes to ethanol-induced fatty liver in mice

Fatty liver is commonly associated with alcohol ingestion and abuse. While the molecular pathogenesis of these fatty changes is well understood, the biochemical and pharmacological mechanisms by which ethanol stimulates these molecular changes remain unknown. During ethanol metabolism, adenosine is generated by the enzyme ecto-5'-nucleotidase, and adenosine production and adenosine receptor activation are known to play critical roles in the development of hepatic fibrosis. We therefore investigated whether adenosine and its receptors play a role in the development of alcohol-induced fatty liver. WT mice fed ethanol on the Lieber-DeCarli diet developed hepatic steatosis, including increased hepatic triglyceride content, while mice lacking ecto-5'-nucleotidase or adenosine A1 or A2B receptors were protected from developing fatty liver. Similar protection was also seen in WT mice treated with either an adenosine A1 or A2B receptor antagonist. Steatotic livers demonstrated increased expression of genes involved in fatty acid synthesis, which was prevented by blockade of adenosine A1 receptors, and decreased expression of genes involved in fatty acid metabolism, which was prevented by blockade of adenosine A2B receptors. In vitro studies supported roles for adenosine A1 receptors in promoting fatty acid synthesis and for A2B receptors in decreasing fatty acid metabolism. These results indicate that adenosine generated by ethanol metabolism plays an important role in ethanol-induced hepatic steatosis via both A1 and A2B receptors and suggest that targeting adenosine receptors may be effective in the prevention of alcohol-induced fatty liver.