Decreased Triglyceride Content Research Articles

Xuezhikang alleviates lipid accumulation via AMPK activation in hepatocellular steatosis model

Xuezhikang (XZK) is an extract of Chinese red yeast rice. It has multiple protective effects in cardiovascular systems. However, the underlying mechanism by which XZK affects free fatty acid (FFA)-induced lipogenesis in hepatocellular steatosis model is still unknown. Herein, we investigated this mechanism in HepG2 cells. The HepG2 cells were treated with palmitate acid (PA) to induce lipogenesis. Then the PA-induced HepG2 cells were subsequently treated with XZK. After 24 h of treatment, we determined the intracellular triglyceride (TG) contents and average areas of lipid droplets. To study the involvement of AMPK signaling pathway, we pre-treated the PA-induced HepG2 cells with Compound C, an AMPK inhibitor, before XZK treatment. Expressions of p-AMPK and AMPK were determined by Western blot. The results showed that XZK decreased TG content and lipid accumulation in hepatocellular steatosis model. Compound C abolished the effects of XZK. These results demonstrated for the first time that XZK protects hepatocytes against lipid accumulation induced by free fatty acids. Its effects may be mediated by the activation of AMPK pathway.

Mendelian randomization analyses support causal relationships between blood metabolites and the gut microbiome.

The gut microbiome has been implicated in a variety of physiological states, but controversy over causality remains unresolved. Here, we performed bidirectional Mendelian randomization analyses on 3,432 Chinese individuals with whole-genome, whole-metagenome, anthropometric and blood metabolic trait data. We identified 58 causal relationships between the gut microbiome and blood metabolites, and replicated 43 of them. Increased relative abundances of fecal Oscillibacter and Alistipes were causally linked to decreased triglyceride concentration. Conversely, blood metabolites such as glutamic acid appeared to decrease fecal Oxalobacter, and members of Proteobacteria were influenced by metabolites such as 5-methyltetrahydrofolic acid, alanine, glutamate and selenium. Two-sample Mendelian randomization with data from Biobank Japan partly corroborated results with triglyceride and with uric acid, and also provided causal support for published fecal bacterial markers for cancer and cardiovascular diseases. This study illustrates the value of human genetic information to help prioritize gut microbial features for mechanistic and clinical studies.

Myostatin suppresses adipogenic differentiation and lipid accumulation by activating crosstalk between ERK1/2 and PKA signaling pathways in porcine subcutaneous preadipocytes.

The current study was undertaken to determine the effect of myostatin (MSTN) on lipid accumulation in porcine subcutaneous preadipocytes (PSPAs) and to further explore the potential molecular mechanisms. PSPAs isolated from Meishan weaned piglets were added with various concentrations of MSTN recombinant protein during the entire period of adipogenic differentiation process. Results showed that MSTN treatment significantly reduced the lipid accumulation, intracellular triglyceride (TG) content, glucose consumption, and glycerol phosphate dehydrogenase activity, while increased glycerol and free fatty acid release. Consistent with above results, the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway was obviously activated and thus key adipogenic transcription factors peroxisome proliferator-activated receptor-gamma (PPAR-γ), CCAAT/enhancer-binding protein-alpha (C/EBP-α), and their downstream enzymes fatty acid synthase and acetyl-CoA carboxylase were all inhibited. However, chemical inhibition of ERK1/2 signaling pathway by PD98059 markedly reversed the decreased TG content by increasing PPAR-γ expression. In addition, MSTN activated the cyclic AMP/protein kinase A (cAMP/PKA) pathway and stimulated lipolysis by reducing the expression of antilipolytic gene perilipin, thus elevated key lipolytic enzymes adipose triglyceride lipase and hormone-sensitive lipase (HSL) expression and enzyme activity. On the contrary, pretreatment with PKA inhibitor H89 significantly reversed TG accumulation by increasing PPAR-γ expression and thus inhibiting ERK1/2, perilipin, and HSL phosphorylation, supporting the crosstalk between PKA and ERK1/2 pathways in both the anti-adipogenic and pro-lipolytic effects. In summary, our results suggested that MSTN suppressed adipogenesis and stimulated lipolysis, which was mainly mediated by activating crosstalk of ERK1/2 and PKA signaling pathways, and consequently decreased lipid accumulation in PSPAs, our findings may provide novel insights for further exploring MSTN as a potent inhibitor of porcine subcutaneous lipid accumulation.

Continuous and intermittent exercise training responses in liver and white adipose tissue aquaglyceroporins

PurposeWe analysed the effects of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on hepatic and adipose tissue aquaglyceroporins (AQPs) in rats fed with high-fat diet (HFD).MethodsOverall, 48 male Wistar rats were fed with a normal diet (ND, 10.4 kcal% fat) or HFD (62.1 kcal% fat) over 10 weeks. Then, the animals were divided into 6 groups: ND sedentary (NS), N + MICT, N + HIIT, HS, H + MICT, and H + HIIT. The trained animals performed 10-week matched distances of MICT and HIIT on a motorized treadmill (5 times/week) while maintaining dietary treatments. The liver and epididymal white adipose tissue (eWAT) were investigated to determine triglycerides (TG) and AQP7 and AQP9 levels.ResultsHFD increased body weight, liver and eWAT weight, plasma insulin and glucose levels, and insulin resistance. Both MICT and HIIT were able to decrease body weight and liver and eWAT weight in the HFD-fed group. HFD increased plasma TG, glucose, and insulin levels, attenuated by MICT and HIIT programs. HFD increased TG content and AQP7 and did not alter AQP9. MICT and HIIT programs decreased hepatic TG content and AQP7 and AQP9 levels in ND-fed animals. In HFD-fed animals, only MICT decreased AQP9, and both MICT and HIIT decreased TG content and AQP7 levels in eWAT.ConclusionsOur findings suggest that the regulation of adipose tissue AQP7 and hepatic AQP9 by both MICT and HIIT interventions can have a significant effect on fat metabolism and glucose homeostasis.

Metabolic and Molecular Subacute Effects of a Single Moderate-Intensity Exercise Bout, Performed in the Fasted State, in Obese Male Rats.

Introduction and objectives: Obesity represents a major global public health problem. Its etiology is multifactorial and includes poor dietary habits, such as hypercaloric and hyperlipidic diets (HFDs), physical inactivity, and genetic factors. Regular exercise is, per se, a tool for the treatment and prevention of obesity, and recent studies suggest that the beneficial effects of exercise can be potentiated by the fasting state, thus potentially promoting additional effects. Despite the significant number of studies showing results that corroborate such hypothesis, very few have evaluated the effects of fasted-state exercise in overweight/obese populations. Therefore, the aim of this study was to evaluate the subacute effects (12 h after conclusion) of a single moderate-intensity exercise bout, performed in either a fed or an 8 h fasted state, on serum profile, substrate-content and heat shock pathway–related muscle protein immunocontent in obese male rats. Methods: Male Wistar rats received a modified high-fat diet for 12 weeks to induce obesity and insulin resistance. The animals were allocated to four groups: fed rest (FER), fed exercise (FEE), fasted rest (FAR) and fasted exercise (FAE). The exercise protocol was a 30 min session on a treadmill, with an intensity of 60% of VO2max. The duration of the fasting period was 8 h prior to the exercise session. After a 12 h recovery, the animals were killed and metabolic parameters of blood, liver, heart, gastrocnemius and soleus muscles were evaluated, as well as SIRT1 and HSP70 immunocontent in the muscles. Results: HFD induced obesity and insulin resistance. Soleus glycogen concentration decreased in the fasted groups and hepatic glycogen decreased in the fed exercise group. The combination of exercise and fasting promoted a decreased concentration of serum total cholesterol and triglycerides. In the heart, combination fasting plus exercise was able to decrease triglycerides to control levels. In the soleus muscle, both fasting and fasting plus exercise were able to decrease triglyceride concentrations. In addition, heat shock protein 70 and sirtuin 1 immunocontent increased after exercise in the gastrocnemius and soleus muscles. Conclusions: An acute bout of moderate intensity aerobic exercise, when realized in fasting, may induce, in obese rats with metabolic dysfunctions, beneficial adaptations to their health, such as better biochemical and molecular adaptations that last for at least 12 h. Considering the fact that overweight/obese populations present an increased risk of cardiovascular events/diseases, significant reductions in such plasma markers of lipid metabolism are an important achievement for these populations.

The effect of Cistus incanus herbal tea supplementation on oxidative stress markers and lipid profile in healthy adults.

Oxidative stress and dyslipidemia play a critical role in the development of cardiovascular disease (CVD). Regular intake of polyphenol-rich diets is associated with a reduced risk of CVDs. The present study was a pilot study with 24 healthy volunteers and was designed to determine if a 12-week administration of Cistus incanus herbal tea, containing phenolic acids and flavonoids, reduces cardiovascular risk factors including oxidative stress and dyslipidemia in healthy adults. Phenolic compounds profile and antibacterial activity of Cistus incanus infusion were also measured. Herbal infusion led to improvement in lipid profile by increase (D4%, p = 0.033) high-density lipoprotein cholesterol concentration and decrease triglyceride (D14%, p = 0.013) concentrations. In addition, the Cistus incanus diet was associated with decreased serum concentrations of malondialdehyde (D16%, p < 0.01) and advanced oxidation protein products (D18%, p < 0.001). Cistus incanus administration decreases cardiovascular risk factors including oxidative stress and dyslipidemia and this action supports the idea of using Cistus incanus tea on a daily basis as an effective dietary component for prevention of atherosclerotic CVD.

ATF6-DGAT pathway is involved in TLR7-induced innate immune response in Ctenopharyngodon idellus kidney cells

DGAT1 and DGAT2 are two acyl-CoA:diacylglycerol O-acyltransferase (DGAT) enzymes that catalyze the final step in triglyceride (TG) synthesis. TGs are the primary constituents of lipid droplets (LDs). Although it has been demonstrated that LDs modulate immune and inflammatory responses in CIK cells, little is known about whether DGAT1 and DGAT2 involve in this process. Firstly, grass carp DGAT2 was isolated and characterized, encoding 361 amino acids, and all DGAT2 proteins in genomic structures are conserved in vertebrates. Then, using TLR7 agonist, we induced LDs accumulation in CIK cells. Only DGAT1b and DGAT2 were upregulated in forming TLR7 agonist induced-LDs. Next, we utilized small-molecule inhibitors of DGAT1 and DGAT2. The results indicated that DGAT1 inactivation attenuated TG content and the relative expressions of IFNα3, NF-κB, IL-1β, and TNFα genes, whereas DGAT2 inhibition decreased TG content and the relative expressions of MyD88, IRF7, IFNα3, NF-κB, IL-1β, and TNFα genes, implying that DGAT1-generated LDs and DGAT2-generated LDs contribute to TLR7-induced immune response via different signaling pathways. Finally, inhibiting ATF6 effectively decreased DGAT-generated LDs accumulation and the expression of TLR7 signaling-related genes induced by TLR7 agonist, implying that ATF6 UPR pathway may mediate the role of DGAT-generated LDs in TLR7 signaling. Overall, we demonstrate that DGAT1 and DGAT2-catalyzed TAG synthesis may generate different LDs to provide distinct signaling platforms for innate TLR7 signaling.

EEF1D facilitates milk lipid synthesis by regulation of PI3K-Akt signaling in mammals.

Mammal's milk is an abundantly foremost source of proteins, lipids, and micronutrients for human nutrition and health. Understanding the molecular mechanisms underlying synthesis of milk components provides practical benefits to improve the milk quality via systematic breeding program in mammals. Through RNAi with EEF1D in primary bovine mammary epithelial cells, we phenotypically observed aberrant formation of cytoplasmic lipid droplets and significantly decreased milk triglyceride level by 37.7%, and exploited the mechanisms by which EEF1D regulated milk lipid synthesis via insulin (PI3K-Akt), AMPK, and PPAR pathways. In the EEF1D CRISPR/Cas9 knockout mice, incompletely developed mammary glands at 9th day postpartum with small or unformed lumens, and significantly decreased triglyceride concentration in milk by 23.4% were observed, as well as the same gene expression alterations in the three pathways. For dairy cattle, we identified a critical regulatory mutation modifying EEF1D transcription activity, which interpreted 7% of the genetic variances of milk lipid yield and percentage. Our findings highlight the significance of EEF1D in mammary gland development and milk lipid synthesis in mammals.

Triglyceride-induced cardiac lipotoxicity is mitigated by Silybum marianum

Background and aimsSilybum marianum (SM) is an herbal product with cytoprotective and antioxidant properties. We have previously demonstrated that SM ameliorates ventricular remodeling and improves cardiac performance. Here, we evaluated whether SM could exert beneficial effects against cardiac lipotoxicity in a pig model of closed-chest myocardial infarction (MI). MethodsStudy 1 investigated the effect of SM administration on lipid profile and any potential SM-related adverse effects. Animals received SM or placebo during 10 days and were afterward sacrificed. Study 2 evaluated the effectiveness of SM daily administration in reducing cardiac lipotoxicity in animals subjected to a 1.5h myocardial infarction (MI), who were subsequently reperfused for 2.5h and euthanized or kept under study for three weeks and then sacrificed. ResultsAnimals administered a 10-day SM regime presented a sharp decline in plasma triglyceride levels vs. controls, with no other modifications in lipid profile. The decrease in triglyceride concentration was accompanied by a marked reduction in triglyceride intestinal absorption and glycoprotein-P expression. Three weeks post-MI the triglyceride content in the ischemic myocardium of the SM-treated animals was significantly lower than in the ischemic myocardium of placebo-controls. This effect was associated with an enhanced cardiac expression of PPARγ and triglyceride clearance receptors. This long-term SM-administration induced a lower expression of lipid receptors in subcutaneous adipose tissue. No SM-related side-effects were registered. ConclusionSM administration reduces plasma triglyceride levels through attenuation of triglyceride intestinal absorption and modulates cardiac lipotoxicity in the ischemic myocardium, likely contributing to improve ventricular remodeling.

Blood pressure lowering, antidyslipidemic and nitric oxide modulatory effects of methanol extract of struchium sparganophora leaves on dexamethasone-salt model of hypertension in rats

ABSTRACT The use of glucocorticoids causes elevation of blood pressure (BP) in man and experimental rats. We evaluated the antihypertensive potential of methanol leaf extract ofStruchium sparganophora (SPA) on dexamethasone-salt-induced hypertension in rats. Rats were assigned randomly to six groups (n=4/group). Group A represented control, while BP elevation (BP≥140/90) was induced in groups B-F via single subcutaneous administration of dexamethasone at a dose of 2 mg/kg with 4% NaCl substituted as drinking water for 5 days. Groups B was left untreated and treatments of other groups twice daily (C-F) for 10 days were as follows: C: nifedipine 3 mg/kg D: nifedipine 3 mg/kg + SPA l300 mg/kg, E: SPA 300 mg/kg and F: SPA 600 mg/kg. BP was read using a noninvasive method, lipid profile and nitric oxide (NO) concentration were determined with appropriate procedures. SPA at 300 and 600 mg/kg markedly decreased the systolic and diastolic BP below suboptimal value of 140/90. Treatment with SPA caused increase (P<0.05) in the levels of HDL-cholesterol and NO as well as concomitant decrease in triglyceride concentration. This study revealed that SPA might lower blood pressure by increasing NO concentration and maintaining lipid homeostasis in hypertensive rats.

Enhancement of Lipolysis in 3T3-L1 Adipocytes by Nitroarene Capsaicinoid Analogs

Transient receptor potential vanilloid 1 (TRPV1) activation by capsaicin binding increased intracellular calcium influx and stimulated adipocyte-to-adipocyte communication, leading to lipolysis. Generally, enhancement of π-stacking capabilities improves certain binding interactions. Notably, nitroarenes exhibit strong binding interactions with aromatic amino acid side chains in proteins. New capsaicinoid analogs were designed by substitution of the OCH3 group with a nitrogen dioxide (NO2) group on the vanillyl ring to investigate how π-stacking interactions in capsaicinoid analogs contribute to lipolysis. Capsaicinoid analogs, nitro capsaicin (5), and nitro dihydrocapsaicin (6) were prepared in moderate yields via coupling of a nitroaromatic amine salt and fatty acids. Oil Red O staining and triglyceride assays with 10 µM loading of capsaicin (CAP), dihydrocapsaicin (DHC), 5, and 6 were performed to investigate their effect on lipolysis in 3T3-L1 adipocytes. Both assay results indicated that 5 and 6 decreased lipid accumulation by 13.6% and 14.7%, respectively, and significantly reduced triglyceride content by 26.9% and 28.4%, respectively, in comparison with the control experiment. Furthermore, the decrease in triglyceride content observed in response to nitroarene capsaicinoid analogs was approximately 2-folds higher than that of CAP and DHC. These results arose from the NO2 group augmented π-π stacking with Tyr511 and the attractive charge interaction with Glu570 affecting binding interactions with TRPV1 receptors.

Alleviation of the Adverse Effect of Dietary Carbohydrate by Supplementation of Myo-Inositol to the Diet of Nile Tilapia (Oreochromis niloticus).

Simple SummaryRecently, the price escalation of fishmeal has made aquaculture nutritionists to consider using carbohydrate in aquafeed to spare the use of dietary protein. However, the high carbohydrate diet could induce lipid metabolism disorder, impair antioxidant capacity, reduce nonspecific immunity and decrease resistance to a pathogen in farmed fish. Myo-inositol is regarded as a vitamin-like essential nutrient for most aquatic animals. Previous studies have shown that dietary supplementation with myo-inositol can reduce lipid accumulation in tissues and decrease the chance of becoming a fatty liver. To explore the mechanism of myo-inositol on alleviating the adverse effect of the high carbohydrate diet in Nile tilapia, six diets contained either low carbohydrate (30%) or high carbohydrate (45%) with three levels of myo-inositol supplementation (0, 400 and 1200 mg/kg diet) to each level of the carbohydrate diet. After an 8-week trial, the result showed that additive myo-inositol in the diet could significantly improve the growth performance and increase the crude protein content of fish. The addition of myo-inositol could effectively decrease the lipid accumulation induced by the high carbohydrate diet by accelerating the transportation of cholesterol back to the liver and promoting the lipid decomposition.This study investigated the effect of dietary myo-inositol (MI) on alleviating the adverse effect of the high carbohydrate diet in Nile tilapia (Oreochromis niloticus). Six diets contained either low carbohydrate (LC 30%) or high carbohydrate (HC 45%) with three levels of MI supplementation (0, 400 and 1200 mg/kg diet) to each level of the carbohydrate diet. After an 8-week trial, the fish fed 400 mg/kg MI under HC levels had the highest weight gain and fatness, but the fish fed 1200 mg/kg MI had the lowest hepatosomatic index, visceral index and crude lipid in the HC group. The diet of 1200 mg/kg MI significantly decreased triglyceride content in the serum and liver compared with those fed the MI supplemented diets regardless of carbohydrate levels. Dietary MI decreased triglyceride accumulation in the liver irrespective of carbohydrate levels. The content of malondialdehyde decreased with increasing dietary MI at both carbohydrate levels. Fish fed 1200 mg/kg MI had the highest glutathione peroxidase, superoxide dismutase, aspartate aminotransferase and glutamic-pyruvic transaminase activities. The HC diet increased the mRNA expression of key genes involved in lipid synthesis (DGAT, SREBP, FAS) in the fish fed the diet without MI supplementation. Dietary MI significantly under expressed fatty acid synthetase in fish fed the HC diets. Moreover, the mRNA expression of genes related to lipid catabolism (CPT, ATGL, PPAR-α) was significantly up-regulated with the increase of dietary MI levels despite dietary carbohydrate levels. The gene expressions of gluconeogenesis, glycolysis and MI biosynthesis were significantly down-regulated, while the expression of the pentose phosphate pathway was up-regulated with the increase of MI levels. This study indicates that HC diets can interrupt normal lipid metabolism and tend to form a fatty liver in fish. Dietary MI supplement can alleviate lipid accumulation in the liver by diverging some glucose metabolism into the pentose phosphate pathway and enhance the antioxidant capacity in O. niloticus.

A Randomized Controlled Trial of Long-Term (R)-α-Lipoic Acid Supplementation Promotes Weight Loss in Overweight or Obese Adults without Altering Baseline Elevated Plasma Triglyceride Concentrations

α-Lipoic acid (LA) is a dietary supplement for maintaining energy balance, but well-controlled clinical trials in otherwise healthy, overweight adults using LA supplementation are lacking. The primary objective was to evaluate whether LA supplementation decreases elevated plasma triglycerides in overweight or obese adults. Secondary aims examined if LA promotes weight loss and improves oxidative stress and inflammation. Overweight adults [n=81; 57% women; 21-60 y old; BMI (in kg/m2)≥25] with elevated plasma triglycerides ≥100mg/dL were enrolled in a 24-wk, randomized, double-blind, controlled trial, assigned to either (R)-α-lipoic acid (R-LA; 600mg/d) or matching placebo, and advised not to change their diet or physical activity. Linear models were used to evaluate treatment effects from baseline for primary and secondary endpoints. R-LA did not decrease triglyceride concentrations, but individuals on R-LA had a greater reduction in BMI at 24 wk than the placebo group (-0.8; P=0.04). The effect of R-LA on BMI was correlated to changes in plasma triglycerides (r = +0.50, P=0.004). Improvement in body weight was greater at 24 wk in R-LA subgroups than in placebo subgroups. Women and obese participants (BMI≥35) showed greater weight loss (-5.0% and -4.8%, respectively; both P<0.001) and loss of body fat (-9.4% and -8.6%, respectively; both P<0.005). Antioxidant gene expression in mononuclear cells at 24 wk was greater in the R-LA group (Heme oxygenase 1 [HMOX1] : +22%; P=0.02) than in placebo. Less urinary F2-isoprostanes (-25%; P=0.005), blood leukocytes (-10.1%; P=0.01), blood thrombocytes (-5.1%; P=0.03), and ICAM-1 (-7.4%; P=0.04) at 24 wk were also observed in the R-LA group than in placebo. Long-term LA supplementation results in BMI loss, greater antioxidant enzyme synthesis, and less potential for inflammation in overweight adults. Improved cellular bioenergetics is also evident in some individuals given R-LA.This trial was registered at clinicaltrials.gov as NCT00765310.

74-OR: The Effect of SERCA2 Activation on Liver Metabolism and Diet-Induced Steatohepatitis in Mice

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver disease, but its progression to the severe form of nonalcoholic steatohepatitis (NASH) is unpredictable. Hepatocyte steatosis alters endoplasmic reticulum (ER) calcium stores and induces mitochondrial dysfunction leading to hepatocellular inflammation and apoptosis. Moreover, obese mice have impaired sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2) function, responsible for transporting Ca2+ from the cytoplasm to ER. We thus hypothesized that restoration of SERCA2 activity may improve hepatocyte function during lipotoxicity. To test this hypothesis, 8-week-old male C57Bl/6J (wild type, WT) or melanocortin-4 receptor knockout (MC4R-/-) mice were placed on either chow or Western diet (WD) for 8 weeks. Half of the WD-fed mice were also given injections of CDN1163 once every two weeks to activate SERCA2. Sodium [13C3]lactate was infused intravenously into conscious, unrestrained mice for 2 hours and 13C-enrichments of plasma glucose and liver metabolites were measured by GC-MS, then used to regress liver metabolic fluxes using the INCA modeling platform. CDN1163 treatment significantly decreased weight and fat mass of both WT and MC4R-/- WD-fed mice without affecting food intake or lean mass. Moreover, CDN1163 improved insulin sensitivity of WT and MC4R-/- mice. CDN1163 decreased NAFLD activity score in WT, but failed to reduce histological features of NASH in MC4R-/- mice. Liver free fatty acids, diglycerides and ceramides were not affected; however, CDN1163 decreased triglyceride content in WT mice. Liver metabolic fluxes analysis revealed that CDN1163 accelerated pyruvate cycling in WT and MC4R-/- mice, which may explain how CDN1163 helped hepatocytes adapt to an excess of energy substrates. Taken together, these data suggest that SERCA2 activation had a protective effect on liver when NAFLD was less severe (WT) but was insufficient to rescue lipotoxicity after progression to NASH had occurred (MC4R-/-). Disclosure T. Bednarski: None. M. Rahim: None. J. Young: Board Member; Self; Metalytics. Consultant; Self; Pfizer Inc. Funding National Institutes of Health (R01DK106348)

(−)-Hydroxycitric acid regulates energy metabolism by activation of AMPK - PGC1α - NRF1 signal pathway in primary chicken hepatocytes

As the most important bioactive substance in Garcinia cambogia, (−)-hydroxycitric acid (HCA) is widely used in food additives to regulate obesity and diabetes in animals or humans, while the mechanism is poorly understood. The purpose of this study was to elucidate the regulatory effect and mechanism of (−)-HCA in regulating glucose and lipid metabolism in chicken primary hepatocytes. The results showed that (−)-HCA obviously decreased triglyceride content through inhibiting the fatty acid synthase protein level, and enhancing the protein level of phosphorylated acetyl CoA carboxylase, enoyl coenzyme A hydratase short chain 1 and carnitine palmitoyltransferase 1A in hepatocytes. Moreover, (−)-HCA markedly enhanced the protein level of phosphofructokinase-1, pyruvate dehydrogenase, succinate dehydrogenase A and complex IV, and which led to the enhancing of glucose uptake and catabolism in hepatocytes. Importantly, the regulation of (−)-HCA on these key factors associated with lipid and glucose metabolism in hepatocytes was mainly achieved through activation of AMP-activated protein kinase/peroxisome proliferator-activated receptor gamma coactivator 1α-nuclear respiratory factor 1 signaling pathway. These results convincingly demonstrated the mechanism of (−)-HCA's regulating on glucose and lipid metabolism, and provided a strategy in prevention of diseases associated with glycolipid metabolic abnormalities in animals, even in humans.

Flavonoids from Acer okamotoanum Inhibit Adipocyte Differentiation and Promote Lipolysis in the 3T3-L1 Cells.

Flavonoids, quercitrin, isoquercitrin (IQ), and afzelin, were isolated from ethyl acetate fraction of Acer okamotoanum. We investigated anti-obesity effects and mechanisms of three flavonoids from A. okamotoanum in the differentiated 3T3-L1 cells. The differentiated 3T3-L1 cells increased triglyceride (TG) contents, compared with non-differentiated normal group. However, treatments of three flavonoids from A. okamotoanum decreased TG contents without cytotoxicity. In addition, they showed significant down-regulation of several adipogenic transcription factors, such as γ-cytidine-cytidine-adenosine-adenosine-thymidine/enhancer binding protein -α, -β, and peroxisome proliferator-activated receptor-γ, compared with non-treated control group. Furthermore, treatment of the flavonoids inhibited expressions of lipogenesis-related proteins including fatty acid synthase, adipocyte protein 2, and glucose transporter 4. Moreover, IQ-treated group showed significant up-regulation of lipolysis-related proteins such as adipose triglyceride lipase and hormone-sensitive lipase. In addition, flavonoids significantly activated 5′-adenosine monophosphate-activated protein kinase (AMPK) compared to control group. In particular, IQ showed higher inhibition of TG accumulation by regulation of pathways related with both adipogenesis and lipolysis, than other flavonoids. The present results indicated that three flavonoids of A. okamotoanum showed anti-obesity activity by regulation of adipocyte differentiation, lipolysis, and AMPK signaling, suggesting as an anti-obesity functional agents.

Human Sperm Express the Receptor for Glucagon-like Peptide-1 (GLP-1), Which Affects Sperm Function and Metabolism.

Glucagon-like peptide-1 (GLP-1) produces pleiotropic effects binding to the GLP-1 receptor (GLP1-R), potentiating insulin secretion in the pancreas. GLP1-R is expressed in peripheral tissues and evidence for its role in reproduction has come from knockout mice, although the relationship between GLP-1 and male fertility needs to be clarified. Given that human sperm is an insulin-sensitive and insulin-secreting cell, we hypothesized that the GLP-1/GLP1-R axis may be expressed and functional in these cells. We revealed the presence of GLP1-R by Western blotting and immunofluorescence analyses. Because Exendin-4 (Ex-4) displays similar functional properties to native GLP-1, we used this agonist to perform a dose-response study on progressive motility and cholesterol efflux, showing that 300 pM Ex-4 was the most effective treatment. These actions are mediated by GLP1-R and independent from sperm-secreted insulin. The exposure to Ex-4 fueled phosphatidylinositol-3-kinase (PI3K)/AKT signaling and was reversed by H89, indicating a protein kinase A (PKA)-dependence of GLP-1/GLP1-R signaling. It emerged that in sperm, insulin secretion regulated by Ex-4 did not occur in a strictly glucose-dependent manner. A stimulatory action of Ex-4/GLP1-R on lactate dehydrogenase and glucose-6-phosphate dehydrogenase (G6PDH) activities was observed. Ex-4/GLP1-R decreased triglycerides content concomitantly to enhanced lipase and acyl-coenzyme A (acyl-CoA) dehydrogenase activities, addressing a lipolytic effect. Collectively, we discovered that human sperm is a new GLP1 incretin target, broadening our knowledge about the effects of the GLP1-R agonist in the male reproductive field. Further findings in humans should be conducted in the future to confirm it and to improve the translational aspect of this study.

Abstract P291: Effects of a Multidisciplinary Lifestyle Intervention on HDL Cholesterol Efflux Capacities in Adolescents With Obesity

Studies have suggested that a reduced HDL cholesterol efflux capacities (CECs) may be associated with an increased risk of coronary heart disease. However, only few studies have evaluated the impact of a lifestyle modification program on HDL-CEC in adolescents with obesity. The objective of this study was to determine if a 16-week lifestyle modification program would improve HDL-CECs in adolescents with obesity. Twenty-nine adolescents with obesity (16 boys and 13 girls) from 11 to 16 years of age (14.0 ± 1.6 years) were selected to participate in this study. The aim of the lifestyle modification program was to improve eating habits and physical activity levels. During the study, each adolescent was followed by a multidisciplinary team and trained three sessions per week for 16 weeks. The exercise program focused on endurance type activities and all training sessions were supervised and performed in groups. Anthropometric data, metabolic variables and HDL-CECs were measured at baseline and at the end of the intervention. HDL-CECs were measured using ( 3 H)cholesterol-labeled J774 macrophages and HepG2 hepatocytes. Body mass index (33.6 to 32.7 kg/m 2 , p&lt;0.0001) and waist circumference (102.4 to 100.5 cm, p=0.001) were significantly reduced after the 16-week intervention program. We also found a significant decrease in triglyceride concentrations (1.28 to 1.04 mmol/L, p=0.02) as well as in total cholesterol/HDL cholesterol ratio (4.42 to 3.91, p=0.0007) whereas HDL cholesterol levels increased (1.03 to 1.14 mmol/L, p=0.002). J774-HDL-CECs and HepG2-HDL-CECs were not significantly modified after the intervention. In order to further explore the impact of intervention-induced changes in HDL cholesterol levels on exercise-induced changes in HDL-CECs, adolescents were divided into two groups according to their changes in HDL cholesterol levels during the study (low or high intervention-induced changes in HDL cholesterol levels). Adolescents with low HDL cholesterol levels intervention-induced changes did not show an increased in HepG2-HDL-CECs. However, a significant improvement in HepG2-HDL-CEC after the intervention was observed among adolescents characterized by the highest intervention-induced changes in HDL cholesterol levels (p=0.03). Intervention-induced changes in HDL cholesterol levels were also significantly associated with changes in HepG2-HDL-CEC (r=0.55; p=0.002). No association was found between changes in HDL cholesterol levels and changes in J774-HDL-CECs. In conclusion, we found that a structured lifestyle modification program leads to significant improvements in cardiometabolic risk profile and in HepG2-HDL-CEC in obese adolescents.

Opuntia cladode powders inhibit adipogenesis in 3\u2009T3-F442A adipocytes and a high-fat-diet rat model by modifying metabolic parameters and favouring faecal fat excretion

BackgroundObesity is a major public health concern worldwide. A sedentary life and a nutritional transition to processed foods and high-calorie diets are contributing factors to obesity. The demand for nutraceutical foods, such as herbal weight-loss products, which offer the potential to counteract obesity, has consequently increased. We hypothesised that Opuntia cladodes consumption could assist weight management in an obesity prevention context.MethodsThis study was designed to explore the anti-adipogenic effects of lyophilised Opuntia cladode powders (OCP) in an in vitro cellular model for adipocyte differentiation and an in vivo high-fat-diet (HFD)-induced obesity rat model. Two OCP were tested, one from wild species O. streptacantha and the second from the most known species O. ficus-indica.ResultsPre-adipocytes 3 T3-F442A were treated by OCP during the differentiation process by insulin. OCP treatment impaired the differentiation in adipocytes, as supported by the decreased triglyceride content and a low glucose uptake, which remained comparable to that observed in undifferentiated controls, suggesting that an anti-adipogenic effect was exerted by OCP. Sprague–Dawley rats were fed with a normal or HFD, supplemented or not with OCP for 8 weeks. OCP treatment slightly reduced body weight gain, liver and abdominal fat weights, improved some obesity-related metabolic parameters and increased triglyceride excretion in the faeces. Taken together, these results showed that OCP might contribute to reduce adipogenesis and fat storage in a HFD context, notably by promoting the faecal excretion of fats.ConclusionsOpuntia cladodes may be used as a dietary supplement or potential therapeutic agent in diet-based therapies for weight management to prevent obesity.Graphical abstract

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

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