Genetic deficiency or pharmacological inhibition of miR-33 protects from kidney fibrosis.

Previous work has reported the important links between cellular bioenergetics and the development of chronic kidney disease, highlighting the potential for targeting metabolic functions to regulate disease progression. More recently, it has been shown that alterations in fatty acid oxidation (FAO) can have an important impact on the progression of kidney disease. In this work, we demonstrate that loss of miR-33, an important regulator of lipid metabolism, can partially prevent the repression of FAO in fibrotic kidneys and reduce lipid accumulation. These changes were associated with a dramatic reduction in the extent of fibrosis induced in 2 mouse models of kidney disease. These effects were not related to changes in circulating leukocytes because bone marrow transplants from miR-33-deficient animals did not have a similar impact on disease progression. Most important, targeted delivery of miR-33 peptide nucleic acid inhibitors to the kidney and other acidic microenvironments was accomplished using pH low insertion peptides as a carrier. This was effective at both increasing the expression of factors involved in FAO and reducing the development of fibrosis. Together, these findings suggest that miR-33 may be an attractive therapeutic target for the treatment of chronic kidney disease.

Genetic Dissection of the Impact of miR-33a and miR-33b during the Progression of Atherosclerosis.

As an important regulator of macrophage cholesterol efflux and HDL biogenesis, miR-33 is a promising target for treatment of atherosclerosis, and numerous studies demonstrate that inhibition of miR-33 increases HDL levels and reduces plaque burden. However, important questions remain about how miR-33 impacts atherogenesis, including whether this protection is primarily due to direct effects on plaque macrophages or regulation of lipid metabolism in the liver. We demonstrate that miR-33 deficiency in Ldlr-/- mice promotes obesity, insulin resistance, and hyperlipidemia but does not impact plaque development. We further assess how loss of miR-33 or addition of miR-33b in macrophages and other hematopoietic cells impact atherogenesis. Macrophage-specific loss of miR-33 decreases lipid accumulation and inflammation under hyperlipidemic conditions, leading to reduced plaque burden. Therefore, the pro-atherogenic effects observed in miR-33-deficient mice are likely counterbalanced by protective effects in macrophages, which may be the primary mechanism through which anti-miR-33 therapies reduce atherosclerosis.

Amelioration of diet-induced steatohepatitis in mice following combined therapy with ASO-Fsp27 and fenofibrate.

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease. NAFLD progresses from benign steatosis to steatohepatitis (NASH) to cirrhosis and is linked to hepatocellular carcinoma. No targeted treatment is currently approved for NAFLD/NASH. We previously showed that fat-specific protein 27 (FSP27), a lipid droplet-associated protein that controls triglyceride turnover in the hepatocyte, is required for fasting- and diet-induced triglyceride accumulation in the liver. However, silencing Fsp27 with antisense oligonucleotides (ASOs) did not improve hepatosteatosis in genetic nor nutritional mouse models of obesity. Herein, we tested the therapeutic potential of ASO-Fsp27 when used in combination with the PPARα agonist fenofibrate. C57BL/6 mice were fed a high-trans-fat, high-cholesterol, high-fructose diet for eight weeks to establish NASH, then kept on diet for six additional weeks while dosed with ASOs and fenofibrate, alone or in combination. Data show that ASO-Fsp27 and fenofibrate synergize to promote resistance to diet-induced obesity and hypertriglyceridemia and to reverse hepatic steatosis, inflammation, oxidative stress, and fibrosis. This multifactorial improvement of liver disease noted when combining both drugs suggests that a course of treatment that includes both reduced FSP27 activity and activation of PPARα could provide therapeutic benefit to patients with NAFLD/NASH.

Therapeutic silencing of fat-specific protein 27 improves glycemic control in mouse models of obesity and insulin resistance.

Obesity is a component of the metabolic syndrome, mechanistically linked to diabetes, fatty liver disease, and cardiovascular disease. Proteins that regulate the metabolic fate of intracellular lipid droplets are potential therapeutic candidates to treat obesity and its related consequences. CIDEC (cell death-inducing DFFA-like effector C), also known in mice as Fsp27 (fat-specific protein 27), is a lipid droplet-associated protein that prevents lipid mobilization and promotes intracellular lipid storage. The consequences of complete loss of FSP27 on hepatic metabolism and on insulin resistance are controversial, as both healthy and deleterious lipodystrophic phenotypes have been reported in Fsp27-/- mice. To test whether therapeutic silencing of Fsp27 might be useful to improve obesity, fatty liver, and glycemic control, we used antisense oligonucleotides (ASOs) in both nutritional (high-fat diet) and genetic (leptin-deficient ob/ob) mouse models of obesity, hyperglycemia, and hepatosteatosis. We show that partial silencing Fsp27 in either model results in the robust decrease in visceral fat, improved insulin sensitivity and whole-body glycemic control, and tissue-specific changes in transcripts controlling lipid oxidation and synthesis. These data suggest that partial reduction of FSP27 activity (e.g., using ASOs) might be exploited therapeutically in insulin-resistant obese or overweight patients.

A combination of resveratrol and quercetin induces browning in white adipose tissue of rats fed an obesogenic diet.

OBJECTIVE: To analyze whether a combination of quercetin (Q) and resveratrol (RSV) would induce a white adipose tissue (WAT) browning effect. METHODS: Thirty-six rats were fed an obesogenic diet and divided into four groups: control, treated with RSV (15 mg/kg body weight/day; RSV group), treated with Q (30 mg/kg body weight/day; Q group), or treated with both polyphenols (RSV + Q group). RESULTS: After 6 weeks, body and WAT weights were significantly reduced in the RSV + Q group. In perirenal WAT of the control, RSV, and Q groups, white unilocular adipocytes appeared in the majority of cells, while in the RSV + Q group numerous multilocular adipocytes with positive immunostaining for UCP1 were observed. The presence of UCP1 was confirmed by Western blot. This group also revealed increased mRNA levels of Cidea, Hocx9, Bmp4, Slc27a1, Pat2, Atgl, and Atp5d. Interscapular brown adipose tissue weight showed no differences between groups, but the Cidea mRNA level was increased in the RSV group, the Cox-2 mRNA level in the RSV + Q group, and UCP1 protein expression in the RSV and the RSV + Q groups. CONCLUSIONS: This study demonstrated that the RSV + Q combination produces a brown-like remodeling effect in perirenal WAT, as well as increased UCP1 protein expression in interscapular brown adipose tissue.

The combination of resveratrol and quercetin enhances the individual effects of these molecules on triacylglycerol metabolism in white adipose tissue.

PURPOSE: The aim of this study was to analyze whether the combination of resveratrol and quercetin showed additive or synergic effects on body fat accumulation and triacylglycerol metabolism in adipose tissue from rats fed an obesogenic diet. METHODS: Rats were divided into four dietary groups: a control group and three groups each treated with either resveratrol (15 mg/kg/day; RSV), quercetin (30 mg/kg/day; Q), or both (15 mg resveratrol/kg/day and 30 mg quercetin/kg/day; RSV + Q) for 6 weeks. White adipose tissues from several anatomical locations were dissected. Serum parameters were analyzed by using commercial kits. The activities of fatty acid synthase and heparin-releasable lipoprotein lipase (HR-LPL) were measured using spectrophotometric and fluorimetric methods, and protein expression of acetyl-CoA carboxylase (ACC), adipose tissue triglyceride lipase (ATGL), and hormone-sensitive lipase (HSL) by western blot. RESULTS: The administration of either resveratrol or quercetin separately did not induce significant reductions in adipose tissue weights. By contrast, the combination of both molecules led to a significant reduction in all the fat depots analyzed. The percentage of reduction in each tissue was greater than the calculated additive effect. HR-LPL activity was reduced in RSV and RSV + Q groups. The activity of HSL was not modified. By contrast, ACC was inhibited and ATGL increased only by the combination of both polyphenols. CONCLUSION: The results obtained demonstrate a synergistic effect between resveratrol and quercetin and suggest that when these molecules are combined, a great number of metabolic pathways involved in adipose tissue triacylglycerol accumulation are affected.

Liver delipidating effect of a combination of resveratrol and quercetin in rats fed an obesogenic diet

Liver steatosis is characterized by an abnormal accumulation of triacylglycerols in this organ. This metabolic disorder is closely associated with obesity. In the present study, we aimed to analyse the effect of a combination of resveratrol and quercetin on liver steatosis in an animal model of dietetic obesity, and to compare it with one induced by the administration of each polyphenol separately. Rats were divided into four dietary groups of nine animals each and fed a high-fat, high-sucrose diet: an untreated control group and three groups treated either with resveratrol (RSV; 15 mg/kg/day), with quercetin (Q; 30 mg/kg/day), or with both (RSV + Q; 15 mg resveratrol/kg/day and 30 mg quercetin/kg/day) for 6 weeks. Liver weight and triacylglycerol content decreased only in the RSV + Q group. A significant reduction in acetyl-CoA carboxylase activity was observed in RSV and RSV + Q groups, without changes in fatty acid synthase activity. A significant increase in carnitine palmitoyltransferase-1a activity was observed only in rats treated with the combination of resveratrol and quercetin, suggesting increased fatty acid oxidation. Citrate synthase, a marker of mitochondrial density, remained unchanged in all groups. No significant changes were observed in the expression of peroxisome proliferator-activated receptor alpha (PPARalpha), nuclear respiratory factor 1 (NRF-1) and transcription factor A mitochondrial (TFAM). In conclusion, resveratrol and quercetin together, combining two doses which were shown to be ineffective singly, is an interesting tool to prevent liver steatosis associated with high-fat high-sucrose feeding. The delipidating effect seems to be mediated by increased fatty acid oxidation not associated with increased mitochondriogenesis, and by reduced de novo lipogenesis

Metabolic faecal fingerprinting of trans-resveratrol and quercetin following a high-fat sucrose dietary model using liquid chromatography coupled to high-resolution mass spectrometry.

Faecal non-targeted metabolomics deciphers metabolic end-products resulting from the interactions among food, host genetics, and gut microbiota. Faeces from Wistar rats fed a high-fat sucrose (HFS) diet supplemented with trans-resveratrol and quercetin (separately or combined) were analysed by liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). Metabolomics in faeces are categorised into four clusters based on the type of treatment. Tentative identification of significantly differing metabolites highlighted the presence of carbohydrate derivatives or conjugates (3-phenylpropyl glucosinolate and dTDP-D-mycaminose) in the quercetin group. The trans-resveratrol group was differentiated by compounds related to nucleotides (uridine monophosphate and 2,4-dioxotetrahydropyrimidine D-ribonucleotide). Marked associations between bacterial species (Clostridium genus) and the amount of some metabolites were identified. Moreover, trans-resveratrol and resveratrol-derived microbial metabolites (dihydroresveratrol and lunularin) were also identified. Accordingly, this study confirms the usefulness of omics-based techniques to discriminate individuals depending on the physiological effect of food constituents and represents an interesting tool to assess the impact of future personalized therapies.

Liver delipidating effect of a combination of resveratrol and quercetin in rats fed an obesogenic diet.

Liver steatosis is characterized by an abnormal accumulation of triacylglycerols in this organ. This metabolic disorder is closely associated with obesity. In the present study, we aimed to analyse the effect of a combination of resveratrol and quercetin on liver steatosis in an animal model of dietetic obesity, and to compare it with one induced by the administration of each polyphenol separately. Rats were divided into four dietary groups of nine animals each and fed a high-fat, high-sucrose diet: an untreated control group and three groups treated either with resveratrol (RSV; 15 mg/kg/day), with quercetin (Q; 30 mg/kg/day), or with both (RSV + Q; 15 mg resveratrol/kg/day and 30 mg quercetin/kg/day) for 6 weeks. Liver weight and triacylglycerol content decreased only in the RSV + Q group. A significant reduction in acetyl-CoA carboxylase activity was observed in RSV and RSV + Q groups, without changes in fatty acid synthase activity. A significant increase in carnitine palmitoyltransferase-1a activity was observed only in rats treated with the combination of resveratrol and quercetin, suggesting increased fatty acid oxidation. Citrate synthase, a marker of mitochondrial density, remained unchanged in all groups. No significant changes were observed in the expression of peroxisome proliferator-activated receptor α (PPARα), nuclear respiratory factor 1 (NRF-1) and transcription factor A mitochondrial (TFAM). In conclusion, resveratrol and quercetin together, combining two doses which were shown to be ineffective singly, is an interesting tool to prevent liver steatosis associated with high-fat high-sucrose feeding. The delipidating effect seems to be mediated by increased fatty acid oxidation not associated with increased mitochondriogenesis, and by reduced de novo lipogenesis.

Resveratrol: anti-obesity mechanisms of action.

Resveratrol is a non-flavonoid polyphenol which belongs to the stilbenes group and is produced naturally in several plants in response to injury or fungal attack. Resveratrol has been recently reported as preventing obesity. The present review aims to compile the evidence concerning the potential mechanisms of action which underlie the anti-obesity effects of resveratrol, obtained either in cultured cells lines and animal models. Published studies demonstrate that resveratrol has an anti-adipogenic effect. A good consensus concerning the involvement of a down-regulation of C/EBPα and PPARγ in this effect has been reached. Also, in vitro studies have demonstrated that resveratrol can increase apoptosis in mature adipocytes. Furthermore, different metabolic pathways involved in triacylglycerol metabolism in white adipose tissue have been shown to be targets for resveratrol. Both the inhibition of de novo lipogenesis and adipose tissue fatty acid uptake mediated by lipoprotein lipase play a role in explaining the reduction in body fat which resveratrol induces. As far as lipolysis is concerned, although this compound per se seems to be unable to induce lipolysis, it increases lipid mobilization stimulated by ß-adrenergic agents. The increase in brown adipose tissue thermogenesis, and consequently the associated energy dissipation, can contribute to explaining the body-fat lowering effect of resveratrol. In addition to its effects on adipose tissue, resveratrol can also acts on other organs and tissues. Thus, it increases mitochondriogenesis and consequently fatty acid oxidation in skeletal muscle and liver. This effect can also contribute to the body-fat lowering effect of this molecule.

¿Son los isómeros del ácido linolénico conjugado una alternativa a isómeros del ácido linoleico conjugado en la prevención de la obesidad? / Are conjugated linolenic acid isomers an alternative to conjugated linoleic acid isomers in obesity prevention?

Pese a sus efectos beneficiosos, se desconoce si el ácido linoleico conjugado (conjugated linoleic acid, CLA) podría producir efectos adversos al ser administrado de forma crónica. Considerando este hecho y dada la controvertida eficacia del CLA en humanos, en los últimos años el ácido linolénico conjugado (CLNA, conjugated linolenic acid) se ha descrito como alternativa al CLA, con un potencial funcional para la prevención de la obesidad, además de tener otros efectos positivos relacionados con la misma. A la vista de los resultados descritos, en lo que respecta a la obesidad, no parece que el CLNA sea una molécula más prometedora que el CLA, dado que el efecto generalmente tiene lugar a dosis más elevadas que las dosis efectivas de CLA. No obstante, dado el escaso número de estudios realizados hasta la fecha, todavía resulta difícil llegar a conclusiones claras acerca del potencial uso de estos CLNA en obesidad y alteraciones relacionadas con ella (resistencia a la insulina, dislipidemias o inflamación)

Despite its benefits, conjugated linoleic acid (CLA) may cause side effects after long-term administration. Because of this and utsthe controversial efficacy of CLA in humans, alternative biomolecules that may be used as functional ingredients have been studied in recent years. Thus, conjugated linolenic acid (CLNA) has been reported to be a potential anti-obesity molecule which may have additional positive effects related to obesity. According to the results reported in obesity, CLNA needs to be given at higher doses than CLA to be effective. However, because of the few studies conducted so far, it is still difficult to reach clear conclusions about the potential use of these CLNAs in obesity and its related changes (insulin resistance, dyslipidemia, or inflammation)

Are conjugated linolenic acid isomers an alternative to conjugated linoleic acid isomers in obesity prevention?

Despite its benefits, conjugated linoleic acid (CLA) may cause side effects after long-term administration. Because of this and the controversial efficacy of CLA in humans, alternative biomolecules that may be used as functional ingredients have been studied in recent years. Thus, conjugated linolenic acid (CLNA) has been reported to be a potential anti-obesity molecule which may have additional positive effects related to obesity. According to the results reported in obesity, CLNA needs to be given at higher doses than CLA to be effective. However, because of the few studies conducted so far, it is still difficult to reach clear conclusions about the potential use of these CLNAs in obesity and its related changes (insulin resistance, dyslipidemia, or inflammation).

Effects of resveratrol on changes induced by high-fat feeding on clock genes in rats.

In mammals, the main component of the circadian system is the suprachiasmatic nucleus in the hypothalamus. However, circadian clocks are also present in most peripheral tissues, such as adipose tissue. The aim of the present study was to analyse the potential effects of resveratrol on changes induced by high-fat feeding in the expression of clock genes and clock-controlled genes in the white adipose tissue from rats. For this purpose, rats were divided into three groups: a control group, fed a standard diet, and two other groups, either fed a high-fat diet supplemented with resveratrol (RSV) or no resveratrol (HF). The expression of clock genes and clock-controlled genes was analysed by RT-PCR. Protein expression and fatty acid synthase (FAS) activity were also analysed. When comparing the controls, the RSV group showed similar patterns of response to the HF group, except for reverse erythroblastosis virus α (Rev-Erbα), which was down-regulated. The expression of this gene reached the same levels as in control rats. The response pattern of protein expression for Rev-Erbα was similar to that found for gene expression. High-fat feeding up-regulated all adipogenic genes and resveratrol did not modify them. In the HF group, the activity of FAS tended to increase, while resveratrol decreased. In conclusion, resveratrol reverses the change induced by high-fat feeding in the expression of Rev-Erbα in adipose tissue, which means that clock machinery is a target for this polyphenol. This change seems to be related to reduced lipogenesis, which might be involved in the body fat-lowering effect of this molecule.

The combination of resveratrol and conjugated linoleic acid is not useful in preventing obesity

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Scientific research is constantly looking for new molecules to be used as functional ingredients to combat obesity. The aim of the present study was to analyse whether resveratrol and conjugated linoleic acid (CLA) together could reduce body fat more efficiently than their separate administration. Thirty-six male Wistar rats were randomly divided into four groups: controls rats (C), rats treated with resveratrol (RSV), rats treated with CLA (CLA) and rats treated with a combination of resveratrol and CLA (RSV+CLA). All rats were fed on an obesogenic diet. In RSV and RSV+CLA groups, the rats received 30 mg resveratrol/kg body weight/day. In CLA and RSV+CLA groups, an equimolecular mixture of trans-10,cis-12 and cis-9,trans-11 was added to the diet to reach 0.5% of the active isomer trans-10,cis-12. After 6 weeks of treatment, white adipose tissue from different anatomical locations was dissected and weighed. Serum triacylglycerols, total and HDL cholesterols, glucose, insulin, fructosamine and TNF-á were measured. A glucose tolerance test was also performed. Separately, resveratrol and CLA significantly reduced body fat but did not do so when combined: 20% in the RSV group and 18% in CLA group but 7% in the RSV+CLA group. Resveratrol reduced serum triacylglycerols. No differences were found among groups in serum cholesterol. Resveratrol, as well as the combination RSV+CLA, improved glycaemic control. These results demonstrate that the combination RSV+CLA reduces the effectiveness of each compound on body fat-lowering action, but it maintains the positive effect of resveratrol on glycaemic control. Consequently, this combination has no usefulness in obesity prevention (AU)

Changes in white adipose tissue metabolism induced by resveratrol in rats.

BACKGROUND: A remarkable range of biological functions have been ascribed to resveratrol. Recently, this polyphenol has been shown to have body fat lowering effects. The aim of the present study was to assess some of the potential underlying mechanisms of action which take place in adipose tissue. METHODS: Sixteen male Sprague-Dawley rats were randomly divided into two groups: control and treated with 30 mg resveratrol/kg body weight/d. All rats were fed an obesogenic diet and after six weeks of treatment white adipose tissues were dissected. Lipoprotein lipase activity was assessed by fluorimetry, acetyl-CoA carboxylase by radiometry, and malic enzyme, glucose-6P-dehydrogenase and fatty acid synthase by spectrophotometry. Gene expression levels of acetyl-CoA carboxylase, fatty acid synthase, lipoprotein lipase, hormone-sensitive lipase, adipose triglyceride lipase, PPAR-gamma, SREBP-1c and perilipin were assessed by Real time RT-PCR. The amount of resveratrol metabolites in adipose tissue was measured by chromatography. RESULTS: There was no difference in the final body weight of the rats; however, adipose tissues were significantly decreased in the resveratrol-treated group. Resveratrol reduced the activity of lipogenic enzymes, as well as that of heparin-releasable lipoprotein lipase. Moreover, a significant reduction was induced by this polyphenol in hormone-sensitive lipase mRNA levels. No significant changes were observed in other genes. Total amount of resveratrol metabolites in adipose tissue was 2.66 ± 0.55 nmol/g tissue. CONCLUSIONS: It can be proposed that the body fat-lowering effect of resveratrol is mediated, at least in part, by a reduction in fatty acid uptake from circulating triacylglycerols and also in de novo lipogenesis.

The combination of resveratrol and conjugated linoleic acid is not useful in preventing obesity.

Scientific research is constantly looking for new molecules to be used as functional ingredients to combat obesity. The aim of the present study was to analyse whether resveratrol and conjugated linoleic acid (CLA) together could reduce body fat more efficiently than their separate administration. Thirty-six male Wistar rats were randomly divided into four groups: controls rats (C), rats treated with resveratrol (RSV), rats treated with CLA (CLA) and rats treated with a combination of resveratrol and CLA (RSV+CLA). All rats were fed on an obesogenic diet. In RSV and RSV+CLA groups, the rats received 30 mg resveratrol/kg body weight/day. In CLA and RSV+CLA groups, an equimolecular mixture of trans-10,cis-12 and cis-9,trans-11 was added to the diet to reach 0.5% of the active isomer trans-10,cis-12. After 6 weeks of treatment, white adipose tissue from different anatomical locations was dissected and weighed. Serum triacylglycerols, total and HDL cholesterols, glucose, insulin, fructosamine and TNF-α were measured. A glucose tolerance test was also performed. Separately, resveratrol and CLA significantly reduced body fat but did not do so when combined: 20% in the RSV group and 18% in CLA group but 7% in the RSV+CLA group. Resveratrol reduced serum triacylglycerols. No differences were found among groups in serum cholesterol. Resveratrol, as well as the combination RSV+CLA, improved glycaemic control. These results demonstrate that the combination RSV+CLA reduces the effectiveness of each compound on body fat-lowering action, but it maintains the positive effect of resveratrol on glycaemic control. Consequently, this combination has no usefulness in obesity prevention.