Anti-Obesity Effect of Different Opuntia stricta var. dillenii's Prickly Pear Tissues and Industrial By-Product Extracts in 3T3-L1 Mature Adipocytes

Opuntia stricta var. dillenii fruit is a source of phytochemicals, such as betalains and phenolic compounds, which may play essential roles in health promotion. The aim of this research was to study the triglyceride-lowering effect of green extracts, obtained from Opuntia stricta var. dillenii fruit (whole fruit, pulp, peel, and industrial by-products (bagasse)) in 3T3-L1 mature adipocytes. The cells were treated on day 12, for 24 h, after the induction of differentiation with the extracts, at doses of 10, 25, 50, or 100 μg/mL. The expression of genes (PCR-RT) and proteins (Western blot) involved in fatty acid synthesis, fatty acid uptake, triglyceride assembly, and triglyceride mobilisation was determined. The fruit pulp extraction yielded the highest levels of betalains, whereas the peel displayed the greatest concentration of phenolic compounds. The extracts from whole fruit, peel and pulp were effective in reducing triglyceride accumulation at doses of 50 μg/mL or higher. Bagasse did not show this effect. The main mechanisms of action underpinning this outcome encompass a reduction in fatty acids synthesis (de novo lipogenesis), thus limiting their availability for triglyceride formation, alongside an increase in triglyceride mobilisation. However, their reliance is contingent upon the specific Opuntia extract.

Altered Red Blood Cell Fatty Acid and Serum Adipokine Profiles in Subjects with Obesity

BACKGROUND

Adipokines, as well as the fatty acid profile of red blood cell (RBC) membranes, are known to play important roles in the development and progression of metabolic complications induced by obesity. Thus, the objective of this study is to compare the serum adipokine profile and the RBC membrane fatty acid profile of normal-weight and obese adults, and to analyze their relationship with serum biochemical parameters.

METHODS

An observational case-control study was performed in 75 normal-weight and obese adult subjects. Biochemical serum parameters, eight serum adipokines and the RBC membrane fatty acid profiles were measured. Associations between parameters were established using regression analysis.

RESULTS

Subjects with obesity showed increased levels of leptin, fibroblast growth factor 21 (FGF21) and overexpressed nephroblastoma (NOV/CCN3), decreased adiponectin, and similar levels of vaspin and chemerin compared to normal-weight subjects. Significant positive and negative correlations were found with triglycerides and high-density lipoprotein-cholesterol (HDL-c), respectively. An increase in the total ω-6 fatty acids in the RBC membrane fatty acid profiles in subjects with obesity was observed, because of higher levels of both dihomo-γ-linolenic acid (DGLA) and arachidonic acid (AA), and decreased total ω-3 fatty acids, mainly due to lower levels of docosahexaenoic acid (DHA). The ω-6/ω-3 ratio in the RBCs was significantly higher, suggesting an inflammatory status, as was also suggested by a reduced adiponectin level. A negative association between DGLA and adiponectin, and a positive association between DHA and serum triglycerides, was observed.

CONCLUSIONS

Important alterations in serum adipokine and RBC fatty acid profiles are found in subjects with obesity.

Lactobacillus rhamnosus GG administration partially prevents diet-induced insulin resistance in rats: a comparison with its heat-inactivated parabiotic

Insulin resistance and type 2 diabetes are obesity-related health alterations, featuring an ever-increasing prevalence. Besides inadequate feeding patterns, gut microbiota alterations stand out as potential contributors to these metabolic disturbances. The aim of this study was to investigate whether the administration of a probiotic (Lactobacillus rhamnosus GG) effectively prevents diet-induced insulin resistance in rats and to compare these potential effects with those exerted by its heat-inactivated parabiotic. For this purpose, 34 male Wistar rats were fed a standard or a high-fat high-fructose diet, alone or supplemented with viable or heat-inactivated Lactobacillus rhamnosus GG. The body and white adipose tissue weight increases, induced by the obesogenic diet, were prevented by probiotic and parabiotic administration. The trend towards higher basal glucose levels and significantly higher serum insulin concentration observed in the non-treated animals fed with the obesogenic diet were effectively reverted by both treatments. Similar results were also found for serum adiponectin and leptin, whose levels were brought back by the probiotic and parabiotic administration to values similar to those of the control animals. Noteworthily, parabiotic administration significantly reduced skeletal muscle triglyceride content and activated CPT-1b compared to the non-treated animals. Finally, both treatments enhanced Akt and AS160 phosphorylation in the skeletal muscle compared to the non-treated animals; however, only parabiotic administration increased GLUT-4 protein expression in this tissue. These results suggest that heat-inactivated Lactobacillus rhamnosus GG seem to be more effective than its probiotic of origin in preventing high-fat high-fructose diet-induced insulin resistance in rats.

Beneficial Effects of Opuntia spp. on Liver Health

The genus Opuntia spp. includes plants capable of growing in arid, temperate and tropical climates. The vast majority of wild species grow in Mexico, but O. ficus-indica (prickly pear or nopal) is cultivated around the world and it is one of the most studied. This review shows the currently available knowledge concerning the action of O. ficus-indica and other Opuntia species (Opuntia vulgaris, Opuntia robusta, Opuntia streptacantha, Opuntia microdasys, Opuntia dillenii and Opuntia dejecta) on liver health. The available data demonstrate the positive effects of extracts, vinegar, juices or seed oil of the Opuntia genus on the alterations induced in the liver by inadequate feeding patterns or the administration of chemicals. In this regard, the potential beneficial effects of nopal are related to the attenuation of triglyceride accumulation, oxidative stress and/or inflammation. Nevertheless, there is no information concerning the bioactive compound's characterisation in most of these studies; consequently, it is not possible to link the therapeutic effects of these plants to the presence of specific compounds in the nopal extracts. Therefore, further research is needed to confirm if the positive effects observed in animal models are also found in humans, in order to determine whether Opuntia can represent an effective tool to prevent and/or manage hepatic alterations.

Anti-Steatotic Effects of Chlorella vulgaris, Nannochloropsis gaditana and Gracilaria vermiculophylla Algae Extracts in AML-12 Hepatocytes

Non-alcoholic fatty liver disease (NAFLD) is considered the most common chronic liver alteration whose prevalence is increasing in Western countries. Microalgae and macroalgae have attracted great interest due to the high content in bioactive compounds with beneficial effects on health. The aim of the present study is to assess the potential interest of extracts rich in proteins obtained from the microalgae Chlorella vulgaris and Nannochloropsis gaditana and the macroalga Gracilaria vermiculophylla in the prevention of lipid accumulation in AML-12 hepatocytes. Toxicity was not observed at any of the tested doses. Both microalgae and the macroalga were effective in preventing triglyceride accumulation, with Nannochloropsis gaditana being the most effective one. Although the three algae extracts were able to increase different catabolic pathways involved in triglyceride metabolism, the mechanisms underlying the anti-steatotic effect were different in each algae extract. In conclusion, the present study demonstrates that Chlorella vulgaris, Nannochloropsis gaditana and Gracilaria vermiculophylla extracts are able to partially prevent the accumulation of triglycerides induced by palmitic acid in cultured hepatocytes, a model used to mimic the steatosis induced in liver by dietary patterns rich in saturated fat.

LC-IMS-HRMS for identification of biomarkers in untargeted metabolomics: The effects of pterostilbene and resveratrol consumption in liver steatosis, animal model

Untargeted metabolomics with the combination of ion mobility separation coupled to high resolution mass spectrometry (IMS-HRMS) was applied to investigate the impact of resveratrol and pterostilbene supplementation on the metabolic fingerprint of the Wistar rats liver with induced liver steatosis. RP-LC and HILIC in both ionisation modes were employed to analyse the liver samples (n = 40) from Wistar rats fed with a high-fat and high-fructose diet, supplemented or not with resveratrol and pterostilbene. After univariate and multivariate statistical analysis, 34 metabolites were highlighted in the different diets and elucidated. Despite the structural similarity, different alterations in liver metabolism were observed by the supplementations. Resveratrol treatment was characterised by the alteration in metabolism of 17 lysophospholipids, while pterostilbene affected some vitamins and derivatives, among others. IMS has demonstrated great potential in the elucidation process thanks to the additional structural descriptor the CCS (Ų), providing more confidence in the identification.

Relationship between changes in microbiota induced by resveratrol and its anti-diabetic effect on type 2 diabetes

Although a general healthy gut microbiota cannot be defined due to numerous internal and external individual factors, such as sex, age, ethnicity, genetics, environment, diet and drugs affect its composition, certain microbial species and gut microbiota compositions seem to be related to the progression of insulin resistance to type 2 diabetes, as well as the development of microvascular and macrovascular complications of diabetes. The present review aimed at gathering the reported information describing how resveratrol induced changes in microbiota composition can mediate the positive effects of this polyphenol on glucose homeostasis under type 2 diabetic conditions, both in animals and humans. Based on the fact that some changes observed in the gut microbiota of type 2 diabetic animals and patients are reversed by resveratrol treatment, and taking into account that some resveratrol mediated changes in gut microbiota composition are similar to those induced by anti-diabetic drugs such as metformin, it can be proposed that four genera, Alistipes, Allobaculum, Desulfovibrio and Blautia could be involved in the benefits of resveratrol on glycameic control. Nevertheless some limitations are observed in this research field: (a) the number of studies analyzing both the effects of resveratrol on glucose homeostasis and microbiota composition in the same cohort of animals, in order to know the potential involvement of microbiota in the anti-diabetic effects of this phenolic compound, are very scarce and practically inexistent in the case of humans., (b) the studies present inconsistencies concerning the effects of resveratrol on gut microbiota changes, (c) the experimental design used do not allow the researchers to establish a causal relationship between the changes in microbiota and the anti-diabetic effect, in the vast majority of the studies, (d) the knowledge about the role of each type of bacteria on glycaemic control is not sufficient so far.

Anti-Obesity Effects of Isorhamnetin and Isorhamnetin Conjugates

Isorhamnetin is a plant-derived secondary metabolite which belongs to the family of flavonoids. This review summarises the main outcomes described in the literature to date, regarding the effects of isorhamnetin on obesity from in vitro and in vivo studies. The studies carried out in pre-adipocytes show that isorhamnetin is able to reduce adipogenesis at 10 μM or higher doses and that these effects are mediated by Pparγ and by Wnt signalling pathway. Very few studies addressed in rodents are available so far. It seems that treatment periods longer than two weeks are needed by isorhamnetin and its glycosides to be effective as anti-obesity agents. Nevertheless, improvements in glycaemic control can be observed even in short treatments. Regarding the underlying mechanisms of action, although some contradictory results have been found, reductions in de novo lipogenesis and fatty acid uptake could be proposed. Further research is needed to increase the scientific evidence referring to this topic; studies in animal models are essential, as well as randomised clinical trials to determine whether the positive results observed in animals could also be found in humans, in order to determine if isorhamnetin and its glycosides can represent a real tool against obesity.

Caffeine, D-glucuronolactone and Taurine Content in Energy Drinks: Exposure and Risk Assessment

The consumption of energy drinks (EDs) is increasing globally while the evidence and concern about the potential health risks are also growing. Caffeine (generally 32 mg/100 mL) together with a wide variety of other active components such as taurine (usually 4000 mg/L) and D-glucuronolactone (generally 2400 mg/L) are the main ingredients of EDs. This study aims to assess the exposures to caffeine, taurine and D-glucuronolactone from EDs in various consumption scenarios and consumer profiles and to characterize the risks by evaluating caffeine and taurine intakes with their reference values and by calculating the margin of safety (MOS) for D-glucuronolactone. While the exposure assessment results showed that caffeine intakes from EDs ranged from 80 to 160 mg (1.14-4 mg/kg b.w.) for the considered scenarios, the risk characterization estimated some risks that could be managed with consumption recommendations such as limiting EDs in 40, 60 and 80 kg b.w. consumers to 175, 262.5 and 350 mL, respectively, to prevent sleep disturbances and to 375, 562.5 and 750 mL to prevent general caffeine adverse health risks, respectively. Dietary exposure to D-glucuronolactone from EDs ranged from 600 to 1200 mg (7.5-30 mg/kg b.w.). As D-glucuronolactone MOS ≥ 100 is only observed when EDs consumption is limited to 250 mL, for individuals weighing above 60 kg, some risks were observed in some of the studied scenarios. A taurine exposure from EDs varied from 1000 to 2000 mg (12.5-50 mg/kg b.w.) and consumptions over 500 mL were estimated to generate intakes above the reference value. In conclusion, the management of these risks requires a European legal framework for EDs with maximum limits for the active components, volume size limitations and labeling improvements along with the development of education and awareness programs and risk communication actions in collaboration with the industry and society.

Resveratrol and Wine: An Overview of Thirty Years in the Digital News

BACKGROUND

Resveratrol's health benefits have received wide media coverage. Since resveratrol is usually associated with wine, informative texts about it should be prepared very carefully, since inaccurate website content could easily change people's wine consumption behavior. This study aimed to assess the quality of informative texts related to resveratrol on science journalism websites.

METHODS

We analyzed 125 resveratrol posts on Science Daily, WebMD, and EurekAlert! published between 1990 and 2020.

RESULTS

A higher number of posts was published in the years in which the number of people looking for information on the internet also increased. The increase can also be related to David Sinclair's notoriety, a fact that we called the "Sinclair effect". Most of the posts are replications of universities' press releases, mainly reporting resveratrol's health benefits, which resulted from preclinical studies and cannot be translated to humans. Most of them mention wine in the text and some in the title.

CONCLUSIONS

Wine is usually mentioned in headline resveratrol news, which could potentially influence wine consumption behavior. Scientists must intensify their efforts to communicate with the public to increase people's health literacy. Online news portals should have science journalists skilled in exploring scientific data and their translation into a simple and accurate language.

Potential usefulness of Mediterranean diet polyphenols against COVID-19-induced inflammation: a review of the current knowledge

The Mediterranean diet is a dietary pattern typical of the populations living in the Mediterranean basin during the 50s-60s of the last century. This diet has demonstrated beneficial effects in the prevention of several pathologies such as cardiovascular diseases, metabolic syndrome, or several cancer types, at least in part, due to its antioxidant compounds. Since the COVID-19 pandemic started, different authors have been studying the effects of certain dietary habits on the presence of COVID-19 and its severity, and the Mediterranean diet is one of them. This review gathers data from studies supporting the potential usefulness of the main phenolic compounds present in the Mediterranean diet, based on their antioxidant and anti-inflammatory effects, as preventive/therapeutic agents against COVID-19. The current evidence supports the potential benefits that hydroxytyrosol, resveratrol, flavonols such as quercetin, flavanols like catechins, and flavanones on the order of naringenin could have on COVID-19. This is due to the increase in the synthesis and translocations of Nrf-2, which increases the activity of antioxidant enzymes and thus reduces ROS production, the scavenging of free radicals, and the suppression of the activity of MMP-9, which is involved in the cytokine storm, and the inhibition of NF-κB.

Effects of Resveratrol Administration in Liver Injury Prevention as Induced by an Obesogenic Diet: Role of Ruminococcaceae

Gut microbiota dysbiosis has been described in several metabolic disruptions, such as non-alcoholic fatty liver disease (NAFLD). Administration of resveratrol has been claimed to elicit benefits against NAFLD along with modulating gut microbiota composition. This investigation aims to study the putative mediating role of gut microbiota in the potential hepato-protective effects of resveratrol in a diet-induced NAFLD rat model. The involvement of bacteria from the Ruminococcaceae family in such effects was also addressed. Resveratrol administration resulted in lowered liver weight and serum total and non-HDL cholesterol concentrations, as well as in increased serum HDL cholesterol levels. The administration of this polyphenol also prevented obesogenic diet-induced serum transaminase increases. In addition, histopathological analysis revealed that resveratrol administration ameliorated the dietary-induced liver steatosis and hepatic inflammation. Gut microbiota sequencing showed an inverse relationship between some bacteria from the Ruminococcaceae family and the screened hepatic markers, whereas in other cases the opposite relationship was also found. Interestingly, an interaction was found between UBA-1819 abundance and resveratrol induced liver weight decrease, suggesting that for this marker resveratrol induced effects were greater when the abundance of this bacteria was high, while no actions were found when UBA-1819 abundance was low.

Role of chemerin in the control of glucose homeostasis

Chemerin is an adipokine produced by the white adipose tissue and other tissues, which plays various roles in the pathogenesis of inflammatory and metabolic diseases in multiple organs. The present review aims at gathering scientific evidence reported in the last ten years, concerning the relationship of chemerin with alterations of glycaemic control, such as insulin resistance, type 2 diabetes and gestational diabetes in humans. Although the vast majority of the studies have shown a positive correlation between the chemerin level and a bad glycaemic control, a general consensus has not been reached. The reported results come from case-control and observational longitudinal studies, thereby limiting their interpretation. In fact, it cannot be stated whether insulin resistance and diabetes lead to an increase in chemerin levels or, on the contrary, if high levels of chemerin contribute to an impaired glycaemic control. Elevated levels of circulating chemerin are also associated with gestational diabetes mellitus. Chemerin gene polymorphisms could be proposed as mediators of glucose-related diseases. Nevertheless, to date very little is known about their implication in glucose metabolism. With regard to the mechanisms of action, chemerin impairs insulin cascade signaling by acting on several proteins of this cascade and by inducing inflammation.

Left atrial strain improves echocardiographic classification of diastolic function in patients with metabolic syndrome and overweight-obesity

BACKGROUND

Current recommendations for echocardiographic assessment of diastolic function (2016 guidelines of the American Society of Echocardiography (ASE)/European Association of Cardiovascular Imaging (EACVI) in patients with metabolic syndrome and overweight/obesity result in a significant number of patients with indeterminate diastolic dysfunction (LVDD). The aim of this article is to study whether the use of the left atrial strain criterion (LALS) reduces the number of indeterminate patients.

METHODS

229 patients were studied with a complete echocardiographic study that included left ventricular longitudinal strain (LVLS) analysis, LALS and a maximal ergospirometry test with assessment of oxygen uptake (VO_2max).

RESULTS

The mean age was 65 ± 5 years, 153 (67%) males, with a mean EF of 60 ± 5%. The mean LVLS was -19.4 ± 2% and the LALS Reservoir was 23.8 ± 7%. There were 140 patients who did not meet LVDD criteria and 82 who did meet the indeterminate LVDD criterion. When the left atrial volume index (LAVI) >34 ml/m² criterion was replaced in the 2016 ASE/EACVI algorithm by LALS Reservoir ≤20%, the number of indeterminate patients was reduced from 36% to 23% (p < 0.001) at the expense of increasing normal studies (61% and 74%). Adding the LALS Reservoir criterion ≤23% in the 82 patients of the indeterminate group resulted in two groups with a different VO_2max (11.6 ± 3 and 18 ± 5 ml/kg/min, p:0.081).

CONCLUSIONS

This study confirms the low prevalence of diastolic dysfunction in overweight/obese patients with metabolic syndrome. Adding left atrial strain criterion to the current recommendations significantly reduces the number of indeterminate patients by reclassifying them as normal.

Food-Based Dietary Guidelines around the World: A Comparative Analysis to Update AESAN Scientific Committee Dietary Recommendations

Food-Based Dietary Guidelines (FBDG) include dietary recommendations based on food groups according to the general and accepted nutrition principles and current scientific evidence. Adoption of FBDG contributes to the prevention of malnutrition in all its forms, promotes human health, and reduces environmental impact. The present review aims to perform an international comparative analysis of the FBDG adopted in different countries from three different continents (America, Asia, and Europe), with particular reference to the Spanish Food Safety and Nutrition Agency (AESAN, Agencia Española de Seguridad Alimentaria y Nutrición) Scientific Committee dietary recommendations. A total of twelve countries with the most updated FBDG and/or closest to the traditional and cultural preferences of Spain were finally selected. All the reviewed FBDG provided recommendations for fruits, vegetables, cereals, legumes, nuts, milk and dairy products, meat and derivatives, fish, eggs, water, and oil; however, remarkable differences regarding recommended amounts were found among countries.

Potential Relationship between the Changes in Circulating microRNAs and the Improvement in Glycaemic Control Induced by Grape Pomace Supplementation

MicroRNAs (miRNAs) represent important tools in medicine and nutrition as new biomarkers, and can act as mediators of nutritional and pharmacological interventions. The aim of the present study was to analyse the effect of grape pomace supplementation on the expression of seven selected miRNAs and their potential relationship with the observed positive effect on glycaemic control, in order to shed light on the mechanism underlying the beneficial effect of this dietary intervention. For this purpose, plasma samples were obtained from 49 subjects with metabolic syndrome. After supplementation with grape pomace (6 weeks), these subjects were categorised as responders (n = 23) or non-responders (n = 26) according to the changes in their fasting insulin rate. MiRNA expression at baseline and at the end of the supplementation was analysed by RT-PCR, and the MiRecords Database was used to identify potential target genes for the studied miRNAs. The increase observed in miR-23a in the whole cohort was present in both subgroups of participants. The increase in miR-181a was significant among non-responders but not responders. The decrease in miR-30c and miR-222 was found in the responders, but not in the non-responders. No changes were observed in miR-10a, miR-151a, miR-181a, and miR-let-7a expressions. After analysing these results, a potential involvement of the reduced expression of miR-30c and miR-222, two microRNAs associated with insulin resistance and diabetes, in the improvement of glycaemic control produced by grape pomace administration, can be proposed. Further research is needed to confirm the involvement of glycolytic enzymes, PI3K, AMPK, and IRS-1 in the effect of grape pomace, as suggested by the changes induced in microRNAs.

An Overview of Adipose Tissue ACE2 Modulation by Diet and Obesity. Potential Implications in COVID-19 Infection and Severity

The present review is aimed at analysing the current evidence concerning the potential modulation of obesity and/or diet in adipose tissue ACE2. Additionally, the potential implications of these effects on COVID-19 are also addressed. The results published show that diet and obesity are two factors that effectively influence the expression of Ace2 gene in adipose tissue. However, the shifts in this gene do not always occur in the same direction, nor with the same intensity. Additionally, there is no consensus regarding the implications of increased adipose tissue ACE2 expression in health. Thus, while in some studies a protective role is attributed to ACE2 overexpression, other studies suggest otherwise. Similarly, there is much debate regarding the role played by ACE2 in COVID-19 in terms of degree of infection and disease outcomes. The greater risk of infection that may hypothetically derive from enhanced ACE2 expression is not clear since the functionality of the enzyme seems to be as important as the abundance. Thus, the greater abundance of ACE2 in adipose tissue of obese subjects may be counterbalanced by its lower activation. In addition, a protective role of ACE2 overexpression has also been suggested, associated with the increase in anti-inflammatory factors that it may produce.

Effect of Microalgae and Macroalgae Extracts on Non-Alcoholic Fatty Liver Disease

The present review aims to gather scientific evidence regarding the beneficial effects of microalgae and macroalgae extracts on non-alcoholic fatty liver disease (NAFLD). The described data show that both microalgae and macroalgae improved this alteration. The majority of the reported studies analysed the preventive effects because algae were administered to animals concurrent with the diet that induced NAFLD. The positive effects were demonstrated using a wide range of doses, from 7.5 to 300 mg/kg body weight/day or from 1 to 10% in the diet, and experimental periods ranged from 3 to 16 weeks. Two important limitations on the scientific knowledge available to date are that very few studies have researched the mechanisms of action underlying the preventive effects of microalgae on NAFLD and that, for the majority of the algae studied, a single paper has been reported. For these reasons, it is not possible to establish the best conditions in order to know the beneficial effects that these algae could bring. In this scenario, further studies are needed. Moreover, the beneficial effects of algae observed in rodent need to be confirmed in humans before we can start considering these products as new tools in the fight against fatty liver disease.

Current Knowledge on Beetroot Bioactive Compounds: Role of Nitrate and Betalains in Health and Disease

An increase in the prevalence of noncommunicable chronic diseases has been occurring in recent decades. Among the deaths resulting from these conditions, cardiovascular diseases (CVD) stand out as the main contributors. In this regard, dietary patterns featuring a high content of vegetables and fruits, such as the Mediterranean and the DASH diets, are considered beneficial, and thus have been extensively studied. This has resulted in growing interest in vegetable-derived ingredients and food-supplements that may have potential therapeutic properties. Among these supplements, beetroot juice, which is obtained from the root vegetable Beta vulgaris, has gained much attention. Although a significant part of the interest in beetroot juice is due to its nitrate (NO₃^-) content, which has demonstrated bioactivity in the cardiovascular system, other ingredients with potential beneficial properties such as polyphenols, pigments and organic acids are also present. In this context, the aim of this review article is to analyze the current knowledge regarding the benefits related to the consumption of beetroot and derived food-supplements. Therefore, this article focuses on nitrate and betalains, which are considered to be the major bioactive compounds present in beetroot, and thus in the derived dietary supplements.

Epigenetic landscape in blood leukocytes following ketosis and weight loss induced by a very low calorie ketogenic diet (VLCKD) in patients with obesity

BACKGROUND

The molecular mechanisms underlying the potential health benefits of a ketogenic diet are unknown and could be mediated by epigenetic mechanisms.

OBJECTIVE

To identify the changes in the obesity-related methylome that are mediated by the induced weight loss or are dependent on ketosis in subjects with obesity underwent a very-low calorie ketogenic diet (VLCKD).

METHODS

Twenty-one patients with obesity (n = 12 women, 47.9 ± 1.02 yr, 33.0 ± 0.2 kg/m²) after 6 months on a VLCKD and 12 normal weight volunteers (n = 6 women, 50.3 ± 6.2 yrs, 22.7 ± 1.5 kg/m²) were studied. Data from the Infinium MethylationEPIC BeadChip methylomes of blood leukocytes were obtained at time points of ketotic phases (basal, maximum ketosis, and out of ketosis) during VLCKD (n = 10) and at baseline in volunteers (n = 12). Results were further validated by pyrosequencing in representative cohort of patients on a VLCKD (n = 18) and correlated with gene expression.

RESULTS

After weight reduction by VLCKD, differences were found at 988 CpG sites (786 unique genes). The VLCKD altered methylation levels in patients with obesity had high resemblance with those from normal weight volunteers and was concomitant with a downregulation of DNA methyltransferases (DNMT)1, 3a and 3b. Most of the encoded genes were involved in metabolic processes, protein metabolism, and muscle, organ, and skeletal system development. Novel genes representing the top scoring associated events were identified, including ZNF331, FGFRL1 (VLCKD-induced weight loss) and CBFA2T3, C3orf38, JSRP1, and LRFN4 (VLCKD-induced ketosis). Interestingly, ZNF331 and FGFRL1 were validated in an independent cohort and inversely correlated with gene expression.

CONCLUSIONS

The beneficial effects of VLCKD therapy on obesity involve a methylome more suggestive of normal weight that could be mainly mediated by the VLCKD-induced ketosis rather than weight loss.

Pterostilbene modifies triglyceride metabolism in hepatic steatosis induced by high-fat high-fructose feeding: a comparison with its analog resveratrol

The use of phenolic compounds as a new therapeutic approach against NAFLD has emerged recently. In the present study, we aim to study the effect of pterostilbene in the prevention of liver steatosis developed as a consequence of high-fat (saturated) high-fructose feeding, by analysing the changes induced in metabolic pathways involved in triglyceride accumulation. Interestingly, a comparison with the anti-steatotic effect of its parent compound resveratrol will be made for the first time. Rats were distributed into 5 experimental groups and fed either a standard laboratory diet or a high-fat high-fructose diet supplemented with or without pterostilbene (15 or 30 mg per kg per d) or resveratrol (30 mg per kg per d) for 8 weeks. Serum triglyceride, cholesterol, NEFA and transaminase levels were quantified. Liver histological analysis was carried out by haematoxylin-eosin staining. Different pathways involved in liver triglyceride metabolism, including fatty acid synthesis, uptake and oxidation, triglyceride assembly and triglyceride release, were studied. Pterostilbene was shown to partially prevent high-fat high-fructose feeding induced liver steatosis in rats, demonstrating a dose-response pattern. In this dietary model, it acts mainly by reducing de novo lipogenesis and increasing triglyceride assembly and release. Improvement in mitochondrial functionality was also appreciated. At the same dose, the magnitude of pterostilbene and resveratrol induced effects, as well as the involved mechanisms of action, were similar.

Metabolically healthy obesity and metabolically obese normal weight: a review

Despite the general relationship between obesity and its co-morbidities, there are both obese individuals who scarcely present the associated pathologies (metabolically healthy obese; MHO) and individuals who present obesity alterations despite having normal weight (metabolically obese normal weight; MONW). It is still difficult to define metabolically MHO and MONW individuals because different classifications have been used in the studies reported. Indeed, different inclusion criteria have been used to discriminate between metabolically healthy and metabolically unhealthy subjects. Due to this and other reasons, such as differences in ethnicity, genetics, and lifestyle of the populations, data concerning the prevalence of MHO and MONW are very variable. The main determinants of MHO are type of growth (hypertrophy or hyperplasia), anatomical location, inflammation of adipose tissue, ectopic fat accumulation, genetic factors, and lifestyles factors. In the case of MONW, the main determinants are genetic background and lifestyle factors. With regard to treatment, it is not clear whether MHO subjects would benefit from traditional lifestyle interventions, based on diet energy restriction and increased physical activity. For MONW subjects, there is still no specialized treatment, and the therapies are the same as those used in obese subjects.

Effects of Pterostilbene on Diabetes, Liver Steatosis and Serum Lipids

Pterostilbene, a phenolic compound derived from resveratrol, possesses greater bioavailability than its parent compound due to the presence of two methoxyl groups. In this review, the beneficial effects of pterostilbene on diabetes, liver steatosis and dyslipidemia are summarized. Pterostilbene is a useful bioactive compound in preventing type 1 diabetes, insulin resistance and type 2 diabetes in animal models. Concerning type 1 diabetes, the main mechanisms described to justify the positive effects of this phenolic compound are increased liver glycogen content and hepatic glucokinase and phosphofructokinase activities, the recovery of pancreatic islet architecture, cytoprotection and a decrease in serum and pancreatic pro-inflammatory cytokines. As for type 2 diabetes, increased liver glucokinase and glucose-6-phosphatase and decreased fructose-1,6-biphosphatase activities are reported. When insulin resistance is induced by diets, a greater activation of insulin signaling cascade has been reported, increased cardiotrophin-1 levels and liver glucokinase and glucose- 6-phosphatase activities, and a decreased fructose-1,6-biphosphatase activity. Data concerning pterostilbene and liver steatosis are scarce so far, but the reduction in oxidative stress induced by pterostilbene may be involved since oxidative stress is related to the progression of steatosis to steatohepatitis. Finally, pterostilbene effectively reduces total cholesterol, LDL-cholesterol and serum triglyceride levels, while increases HDL-cholesterol in animal models of dyslipidemia.

Key Aspects in Nutritional Management of COVID-19 Patients

This review deals with the relationship among nutrition, the immune system, and coronavirus disease 2019 (COVID-19). The influence of nutrients and bioactive molecules present in foodstuffs on immune system activity, the influence of COVID-19 on the nutritional status of the patients, and the dietary recommendations for hospitalized patients are addressed. Deficient nutritional status is probably due to anorexia, nausea, vomiting, diarrhea, hypoalbuminemia, hypermetabolism, and excessive nitrogen loss. There is limited knowledge regarding the nutritional support during hospital stay of COVID-19 patients. However, nutritional therapy appears as first-line treatment and should be implemented into standard practice. Optimal intake of all nutrients, mainly those playing crucial roles in immune system, should be assured through a diverse and well-balanced diet. Nevertheless, in order to reduce the risk and consequences of infections, the intakes for some micronutrients may exceed the recommended dietary allowances since infections and other stressors can reduce micronutrient status. In the case of critically ill patients, recently published guidelines are available for their nutritional management. Further, several natural bioactive compounds interact with the angiotensin-converting enzyme 2 (ACE2) receptor, the gateway for severe acute respiratory syndrome (SARS) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Natural bioactive compounds can also reduce the inflammatory response induced by SARS-CoV-2. These compounds are potential beneficial tools in the nutritional management of COVID-19 patients.

Anti-Obesity Effects of Macroalgae

Macroalgae have attracted great interest for their potential applications in nutraceutical and pharmaceutical industries as source of bioactive medicinal products and food ingredients. This review gathers data from in vitro and in vivo studies addressing the anti-obesity effects of macroalgae. Great consensus exists in all reported in vitro studies concerning the reduction induced by seaweed extracts in the expression of transcriptional factors controlling adipogenesis. In animals, macroalgae reduced body fat accumulation and prevented other obesity features, such as dyslipidemia, insulin resistance and fatty liver. These effects are not due to food intake reduction, since few studies have reported such event. Indeed, the effects on metabolic pathways in target tissues/organs seem to play a more relevant role. Macroalgae can reduce de novo lipogenesis, limiting fatty acid availability for triglyceride synthesis in white adipose tissue. This effect has been observed in both cell cultures and adipose tissue from animals treated with macroalgae extracts. In addition, increased fatty acid oxidation and thermogenic capacity, as well as a shift towards healthier gut microbiota composition may contribute to the body fat-lowering effect of macroalgae. Studies in humans are needed to determine whether macroalgae can represent a feasible tool to prevent and/or manage overweight and obesity.

An energy restriction-based weight loss intervention is able to reverse the effects of obesity on the expression of liver tumor-promoting genes

The epidemiological evidence regarding the association of obesity with liver disease and possibly hepatocellular carcinoma highlights the need for investigations of whether obesity itself could induce the differential expression of genes commonly associated with the initial phase of liver tumorigenesis, and whether such phenomenon could be reversed after a weight loss intervention. In this study, obese Zucker rats were found to have dysregulated cell proliferation, antioxidative defenses, and tumor suppressor gene expression in association with liver dysfunction parameters, as well as oxidative stress and inflammation. Importantly, after a 4-week weight loss protocol of energy restriction and/or exercise, this effect on the liver carcinogenesis-related genes was reversed concomitantly with reductions in the fat mass, hepatic lipid content, oxidative stress, and inflammation. The findings indicate that the oxidative stress and inflammation associated with excess adiposity promote dysregulation of the genes involved in liver tumorigenesis. This is clinically relevant because these effects were detectable in the liver without evidence of a tumoral mass and were reversed after weight loss. Consequently, this study reveals the susceptibility of obese individuals to the initiation of a hepatocarcinogenic process, and how this can be prevented by achieving a healthy body weight.

Effect of a Very-Low-Calorie Ketogenic Diet on Circulating Myokine Levels Compared with the Effect of Bariatric Surgery or a Low-Calorie Diet in Patients with Obesity

: The preservation of muscle mass and muscle function after weight loss therapy is currently a considerable challenge in the fight against obesity. Muscle mass secretes proteins called myokines that have relevant functions in the regulation of metabolism and health. This study was aimed to evaluate whether a very low-calorie ketogenic (VLCK) diet may modulate myokine levels, in addition to changes in body composition, compared to a standard, balanced low-calorie (LC) diet or bariatric surgery in patients with obesity. Body composition, ketosis, insulin sensitivity and myokines were evaluated in 79 patients with overweight/obesity after a therapy to lose weight with a VLCK diet, a LC diet or bariatric surgery. The follow-up was 6 months. The weight loss therapies induced changes in myokine levels in association with changes in body composition and biochemical parameters. The effects on circulating myokine levels compared to those at baseline were stronger after the VLCK diet than LC diet or bariatric surgery. Differences reached statistical significance for IL-8, MMP2 and irisin. In conclusion, nutritional interventions or bariatric surgery to lose weight induces changes in circulating myokine levels, being this effect potentially most notable after following a VLCK diet.

Has the adipokine profile an influence on the catch-up growth type in small for gestational age infants?

Infants born small for gestational age (SGA) are at increased risk of perinatal morbidity, persistent short stature, and metabolic alterations in later life. Moreover, the post-natal growth pattern of SGA infants may be an important contributor to health outcomes later in life, which can be influenced by adipokines. The aims of this study were to compare plasma adipokine profiles (leptin, adiponectin, vaspin, chemerin, and nephroblastoma overexpressed (NOV/CCN3)) among SGA newborns aged 3 months, with low, normal, or high catch-up, to search for potential differences between males and females and to analyze the evolution of several adipokines in plasma from SGA newborns between 3 and 24 months. This prospective, longitudinal study was addressed in SGA Caucasian subjects at Hospital Universitario de Álava-Txagorritxu. We observed that infants with fast catch-up showed significantly lower birth weight than the other two groups. As far as adipokines are concerned, they could have an influence on catch-up type because differences among the three experimental groups were found. It may be proposed that health prognoses in infants with slow and fast catch-up are opposite, not only in adulthood but also during their first months. Finally, adipokine evolution patterns during the first 24 months of age differ, depending on the adipokine, and 24-month-old males show lower levels of leptin, adiponectin, and omentin than females.

Pterostilbene Reduces Liver Steatosis and Modifies Hepatic Fatty Acid Profile in Obese Rats

Excessive fat accumulation within the liver is known as “simple hepatic steatosis”, which is the most benign form of non-alcoholic fatty liver disease (NAFLD). The aim of the present study was to determine whether pterostilbene improves this hepatic alteration in Zucker (fa/fa) rats. Animals were distributed in two experimental groups (n = 10) and fed a standard laboratory diet. Rats in the pterostilbene group were given a dose of 30 mg/kg body weight/d for six weeks. After sacrifice, serum glucose, transaminase, and insulin concentrations were quantified and the liver triacylglycerol content and fatty acid profile was analyzed. Different pathways of triacylglycerol metabolism in liver were studied, including fatty acid synthesis and oxidation, triglyceride assembly, fatty acid uptake, and glucose uptake. With pterostilbene administration, a reduction in insulin concentrations (consequently in the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR)) and hepatic triacylglycerol content were observed. No effects were observed in pterostilbene-treated rats in the activity of de novo lipogenesis enzymes. An improvement in the fatty acid profile was observed in pterostilbene-treated rats. In conclusion, pterostilbene is a useful molecule to reduce liver steatosis. Its delipidating effect is due, at least in part, to reduced fatty acid availability and triacylglycerol synthesis, as well as to an increased very low-density lipoprotein assembly and fatty acid oxidation.

Diastolic dysfunction and exercise capacity in patients with metabolic syndrome and overweight/obesity

Background

Left ventricle diastolic dysfunction (LVDD) is a common finding in high risk individuals, its presence being associated with reduced exercise capacity (EC). We assessed the prevalence of LVDD, applying the 2016 guidelines of the American Society of Echocardiography (ASE)/European Association of Cardiovascular Imaging (EACVI), in a population with overweight/obesity and metabolic syndrome and its association with EC.

Methods and results

This was a prospective, cross-sectional study of a cohort of 235 patients (mean age of 65 ± 5 years old and 33% female) without heart disease and an ejection fraction >50% who underwent a complete echocardiographic assessment and cardiopulmonary exercise testing. Individuals meeting three or more criteria of the 2016 ASE/EACVI guidelines are considered to have LVDD, while tests are considered indeterminate in those meeting only two. Overall, 178 (76%) of our patients met one echocardiographic cutoff value for LVDD, 91 (39%) met two and 7 (3%) three or more. Patients meeting three cutoffs values showed a significant reduction in maximal oxygen uptake (16 ± 3 vs. 19.6 ± 5 ml/kg/min, p < .05), unlike those with indeterminate tests. In multiple regression analysis, meeting three cutoffs was associated with number of METS (ß = −2.2, p = .018). In exploratory analysis, using two criteria based on cutoffs different from those proposed in the guidelines, we identified groups with different EC.

Conclusions

The application of 2016 ASE/EACVI guidelines limited the prevalence of LVDD to 3%. This group showed a clear reduction of the EC. New echocardiographic cutoff values proposed in this study allow us to establish subgroups with different levels of EC.

Association between maximal oxygen consumption and physical activity and sedentary lifestyle in metabolic syndrome. Usefulness of questionnaires

INTRODUCTION AND OBJECTIVES

To analyze whether variations in physical activity (PA) and sedentary behaviors are accompanied by differences in maximal oxygen consumption (VO_2max).

METHODS

We conducted a prospective cross-sectional study of 243 participants (82 women), aged 65.0±4.9 years old, with metabolic syndrome and overweight/obesity who performed a maximal exercise test with expired gas analysis. PA was evaluated using subjective methods, the REGICOR and RAPA 1 self-reported questionnaires, and objective methods, the chair test and accelerometry. Sedentariness was analyzed with the Nurses' Health Study questionnaire and accelerometry.

RESULTS

VO_2max was higher in participants who reported they adhered to the recommendations of the PA guidelines in the REGICOR questionnaire (21.3±4.6 vs 18.0±4.4 mL/kg/min; P <.001) and was 18% higher in those who reported more PA in the RAPA 1 questionnaire than the less active group (P <.001). The chair test (> 15 vs ≤ 15 repetitions) also showed significant differences in VO_2max (21.2±4.8 vs 18.7±4.5 ml/kg/min; P <.001). Correlations between PA variables and VO_2max were significant but low (r: 0.2 to 0.4). Sedentary activities showed less relationship with VO_2max.

CONCLUSIONS

Participants with metabolic syndrome and overweight/obesity who reported adhering to PA recommendations achieved higher VO_2max. The self-reported questionnaires and the chair test identified significant variations in VO_2max. Sedentary activities do not appear to modify VO_2max.

Involvement of 5'-Activated Protein Kinase (AMPK) in the Effects of Resveratrol on Liver Steatosis

This review focuses on the role of 5′AMP-activated protein kinase (AMPK) in the effects of resveratrol (RSV) and some RSV derivatives on hepatic steatosis. In vitro studies, performed in different hepatic cell models, have demonstrated that RSV is effective in preventing liver TG accumulation by activating AMPK, due to its phosphorylation. These preventive effects have been confirmed in studies conducted in animal models, such as mice and rats, by administering the phenolic compound at the same time as the diet which induces TG accumulation in liver. The literature also includes studies focused on other type of models, such as animals showing alcohol-induced steatosis or even steatosis induced by administering chemical products. In addition to the preventive effects of RSV on hepatic steatosis, other studies have demonstrated that it can alleviate previously developed liver steatosis, thus its role as a therapeutic tool has been proposed. The implication of AMPK in the delipidating effects of RSV in in vivo models has also been demonstrated.

Hesperidin and capsaicin, but not the combination, prevent hepatic steatosis and other metabolic syndrome-related alterations in western diet-fed rats

We aimed to assess the potential effects of hesperidin and capsaicin, independently and in combination, to prevent the development of obesity and its related metabolic alterations in rats fed an obesogenic diet. Three-month-old male Wistar rats were divided into 5 groups: Control (animals fed a standard diet), WD (animals fed a high fat/sucrose (western) diet), HESP (animals fed a western diet + hesperidin (100 mg/kg/day)), CAP (animals fed a western diet + capsaicin (4 mg/kg/day)), and HESP + CAP (animals fed a western diet + hesperidin (100 mg/kg/day) + capsaicin (4 mg/kg/day)). Hesperidin and capsaicin were administered by gavage. Capsaicin decreased body fat gain and prevented insulin resistance, whereas hesperidin showed little effect on body fat gain and no apparent effects on insulin resistance. No additive effects were observed with the combination. Capsaicin and hesperidin, separately, improved blood lipid profile, diminished hepatic lipid accumulation, and prevented non-alcoholic steatohepatitis in western diet-fed rats, but the combination showed lower effects. Hesperidin alone, and to a lesser extent capsaicin or the combination, displayed hypotensive effects in western diet-fed rats. In conclusion, capsaicin and hesperidin, separately, exhibit health beneficial effects on metabolic syndrome-related alterations in western diet-fed rats, but the effects are mitigated with the combination.

Combination of Capsaicin and Hesperidin Reduces the Effectiveness of Each Compound To Decrease the Adipocyte Size and To Induce Browning Features in Adipose Tissue of Western Diet Fed Rats

We explored the potential of hesperidin and capsaicin, separately and in combination, to induce white adipose tissue (WAT) browning and to help body weight management in Western diet-fed rats. Adult male Wistar rats were fed for 8 weeks with Western diet and treated daily with hesperidin (100 mg/kg/day), capsaicin (4 mg/kg/day), hesperidin (100 mg/kg/day) + capsaicin (4 mg/kg/day), or the vehicle. Hesperidin and capsaicin separately, but not (or to a lesser extent) the combination, resulted in a decreased size of adipocytes and induced emergence of multilocular brown-like adipocytes positive for UCP1 and CIDEA in retroperitoneal WAT. Expression levels of browning markers, such as Prdm16, in inguinal WAT also increased with capsaicin treatment compared with the vehicle (145% ± 17% vs 92% ± 21%, P < 0.05), but no significant effects were found with the combination (106% ± 12%). Thus, the combination of both bioactives reduces the effectiveness of each compound to decrease the adipocyte size and induce WAT browning.

Resveratrol and Pterostilbene, Two Analogue Phenolic Compounds, Affect Aquaglyceroporin Expression in a Different Manner in Adipose Tissue

Aquaglyceroporins (AQPs) are transmembrane channels that mediate glycerol release and glycerol uptake. They are involved in fat metabolism, with implications in obesity. The aim was to determine whether the administration of resveratrol and pterostilbene during the six weeks of the experimental period would modify AQPs expression in white and brown adipose tissues from Wistar rats fed an obesogenic diet, and to establish a potential relationship with the delipidating properties of these compounds. Consequently, thirty-six rats were divided into four groups: (a) group fed a standard diet; and three more groups fed a high-fat high-sucrose diet: (b) high-fat high-sucrose group: (c) pterostilbene-treated group (30 mg/kg/d): (d) resveratrol-treated group (30 mg/kg/d). Epididymal, subcutaneous white adipose tissues and interscapular brown adipose tissue were dissected. AQPs gene expression (RT-PCR) and protein expression (western-blot) were measured. In white adipose tissue, pterostilbene reduced subcutaneous adipose tissue weight and prevented the decrease in AQP9 induced by obesogenic feeding, and thus glycerol uptake for triglyceride accumulation. Resveratrol reduced epididymal adipose tissue weight and avoided the decrease in AQPs related to glycerol release induced by high-fat high-sucrose feeding, suggesting the involvement of lipolysis in its body-fat lowering effect. Regarding brown adipose tissue, AQP7 seemed not to be involved in the previously reported thermogenic activity of both phenolic compounds.

Yerba Mate Stimulates Mitochondrial Biogenesis and Thermogenesis in High-Fat-Diet-Induced Obese Mice

SCOPE

The potential effects of yerba mate (YM) on mitochondrial biogenesis and thermogenesis are evaluated.

METHODS AND RESULTS

The in vitro effects of YM on mitochondrial respiration are assessed in C2C12 cells. The expression of genes related to mitochondrial biogenesis and thermogenesis are analyzed by quantitative PCR. The in vivo experiments are performed on mice fed a high-fat diet (HFD) and treated with YM extract. Indirect calorimetry was performed, and the expression of genes and proteins related to mitochondrial biogenesis, thermogenesis, and de novo lipogenesis is determined by quantitative PCR and western blot. Our in vitro data indicate that YM increases mtDNA copy number as well as mitochondrial spare respiratory capacity and coupling efficiency. The gene expression profile reinforces this evidence, indicating a modulation of genes downstream of Ampk. In vivo, it is found that YM partially prevents diet-induced obesity by increasing energy expenditure and enhancing mitochondrial biogenesis via the AMPK/SIRT1/PGC1α pathway.

CONCLUSIONS

YM stimulates mitochondriogenesis and Ucp expression, leading to an increase in the spare respiratory capacity and energy dissipation. These effects may help to better understand the potential use of YM for obesity treatment.

Screening of potential anti-adipogenic effects of phenolic compounds showing different chemical structure in 3T3-L1 preadipocytes

This study was designed to analyze the anti-adipogenic effect of fifteen phenolic compounds from various chemical groups in 3T3-L1 pre-adipocytes. Cells were treated with 25 μM, 10 μM or 1 μM of apigenin, luteolin, catechin, epicatechin, epigallocatechin, genistein, daizein, naringenin, hesperidin, quercetin, kaempferol, resveratrol, vanillic acid, piceatannol and pterostilbene for 8 days. At 25 μM lipid accumulation was reduced by all the compounds, with the exception of catechin, epicatechin and epigallocatechin. At a dose of 10 μM apigenin, luteolin, naringenin, hesperidin, quercetin and kaempferol induced significant reductions, and at 1 μM only naringenin, hesperidin and quercetin were effective. The expression of c/ebpα was not. C/ebpβ was significantly reduced by genistein and kaempferol, pparγ by genistein and pterostilbene, srebp1c by luteolin, genistein, hesperidin, kaempferol, pterostilbene and vanillic acid, and lpl by kaempferol. In conclusion, the most effective phenolic compounds are naringenin, hesperidin and quercetin. Differences were found in terms of effects on the expression of genes involved in adipogenesis among the analyzed compounds.

Involvement of autophagy in the beneficial effects of resveratrol in hepatic steatosis treatment. A comparison with energy restriction

Involvement of autophagy in the liver delipidating effects of resveratrol and energy restriction.

Resveratrol-Induced Effects on Body Fat Differ Depending on Feeding Conditions

Science constantly seeks to identify new molecules that could be used as dietary functional ingredients in the fight against obesity and its co-morbidities. Among them, polyphenols represent a group of molecules of increasing interest. One of the most widely studied polyphenols is resveratrol (trans-3,4',5-trihydroxystilbene), which has been proposed as an "energy restriction mimetic" because it can exert energy restriction-like effects. The aim of this review is to analyze the effects of resveratrol on obesity under different feeding conditions, such as overfeeding, normal feeding, and energy restriction, in animals and humans. The vast majority of the studies reported have addressed the administration of resveratrol to animals alongside an obesogenic diet. Under these experimental conditions usually a decreased body weight amount was found. To date, studies that focus on the effects of resveratrol under normal feeding or energy restriction conditions in animals and humans are scarcer. In these studies no changes in body fat were reported. After analyzing the results obtained under overfeeding, normal feeding, and energy restriction conditions, it can be stated that resveratrol is useful in reducing body fat accumulation, and thus preventing obesity. Nevertheless, for ethical reasons, these results have been obtained in animals. By contrast, there are no evidences showing the usefulness of this phenolic compound in reducing previously accumulated body fat. Consequently, as of yet, there is not scientific support for proposing resveratrol as a new anti-obesity treatment tool.

Role of Omentin, Vaspin, Cardiotrophin-1, TWEAK and NOV/CCN3 in Obesity and Diabetes Development

Adipose tissue releases bioactive mediators called adipokines. This review focuses on the effects of omentin, vaspin, cardiotrophin-1, Tumor necrosis factor-like Weak Inducer of Apoptosis (TWEAK) and nephroblastoma overexpressed (NOV/CCN3) on obesity and diabetes. Omentin is produced by the stromal-vascular fraction of visceral adipose tissue. Obesity reduces omentin serum concentrations and adipose tissue secretion in adults and adolescents. This adipokine regulates insulin sensitivity, but its clinical relevance has to be confirmed. Vaspin is produced by visceral and subcutaneous adipose tissues. Vaspin levels are higher in obese subjects, as well as in subjects showing insulin resistance or type 2 diabetes. Cardiotrophin-1 is an adipokine with a similar structure as cytokines from interleukin-6 family. There is some controversy regarding the regulation of cardiotrophin-1 levels in obese -subjects, but gene expression levels of cardiotrophin-1 are down-regulated in white adipose tissue from diet-induced obese mice. It also shows anti-obesity and hypoglycemic properties. TWEAK is a potential regulator of the low-grade chronic inflammation characteristic of obesity. TWEAK levels seem not to be directly related to adiposity, and metabolic factors play a critical role in its regulation. Finally, a strong correlation has been found between plasma NOV/CCN3 concentration and fat mass. This adipokine improves insulin actions.

Lack of Additive Effects of Resveratrol and Energy Restriction in the Treatment of Hepatic Steatosis in Rats

The aims of the present study were to analyze the effect of resveratrol on liver steatosis in obese rats, to compare the effects induced by resveratrol and energy restriction and to research potential additive effects. Rats were initially fed a high-fat high-sucrose diet for six weeks and then allocated in four experimental groups fed a standard diet: a control group, a resveratrol-treated group, an energy restricted group and a group submitted to energy restriction and treated with resveratrol. We measured liver triacylglycerols, transaminases, FAS, MTP, CPT1a, CS, COX, SDH and ATP synthase activities, FATP2/FATP5, DGAT2, PPARα, SIRT1, UCP2 protein expressions, ACC and AMPK phosphorylation and PGC1α deacetylation. Resveratrol reduced triacylglycerols compared with the controls, although this reduction was lower than that induced by energy restriction. The mechanisms of action were different. Both decreased protein expression of fatty acid transporters, thus suggesting reduced fatty acid uptake from blood stream and liver triacylglycerol delivery, but only energy restriction reduced the assembly. These results show that resveratrol is useful for liver steatosis treatment within a balanced diet, although its effectiveness is lower than that of energy restriction. However, resveratrol is unable to increase the reduction in triacylglycerol content induced by energy restriction.

Low Oxygen Consumption is Related to a Hypomethylation and an Increased Secretion of IL-6 in Obese Subjects with Sleep Apnea-Hypopnea Syndrome

Background: Deoxyribonucleic acid (DNA) methylation is an epigenetic modification involved in gene expression regulation, usually via gene silencing, which contributes to the risks of many multifactorial diseases. The aim of the present study was to analyze the influence of resting oxygen consumption on global and gene DNA methylation as well as protein secretion of inflammatory markers in blood cells from obese subjects with sleep apnea-hypopnea syndrome (SAHS). Methods: A total of 44 obese participants with SAHS were categorized in 2 groups according to their resting oxygen consumption. DNA methylation levels were evaluated using a methylation-sensitive high resolution melting approach. Results: The analyzed interleukin 6 (IL6) gene cytosine phosphate guanine (CpG) islands showed a hypomethylation, while serum IL-6 was higher in the low compared to the high oxygen consumption group (p < 0.05). Moreover, an age-related loss of DNA methylation of tumor necrosis factor (B = -0.82, 95% CI -1.33 to -0.30) and long interspersed nucleotide element 1 (B = -0.46; 95% CI -0.87 to -0.04) gene CpGs were found. Finally, studied CpG methylation levels of serpin peptidase inhibitor, clade E member 1 (r = 0.43; p = 0.01), and IL6 (r = 0.41; p = 0.02) were positively associated with fat-free mass. Conclusions: These findings suggest a potential role of oxygen in the regulation of inflammatory genes. Oxygen consumption measurement at rest could be proposed as a clinical biomarker of metabolic health.

Comparative effects of energy restriction and resveratrol intake on glycemic control improvement

Resveratrol (RSV) has been proposed as an energy restriction mimetic. This study aimed to compare the effects of RSV and energy restriction on insulin resistance induced by an obesogenic diet. Any additive effect of both treatments was also analyzed. Rats were fed a high-fat high-sucrose diet for 6 weeks. They were then distributed in four experimental groups which were either fed a standard control diet (C), or treated with RSV (30 mg/kg/d), or submitted to energy restriction (R, 15%), or treated with RSV and submitted to energy restriction (RR). A glucose tolerance test was performed, and serum glucose, insulin, fructosamine, adiponectin, and leptin concentrations determined. Muscle triacylglycerol content and protein expression of insulin receptor (IRβ), protein kinase B (Akt), Akt substrate of 160 kDa (AS160) and glucose transporter 4 (GLUT-4) were measured. In RSV rats, fructosamine concentrations were reduced, HOMA-IR remained unchanged, but glucose tolerance was improved, without changes in phosphorylation of IRβ, Akt, and AS160 or in GLUT-4 protein expression. Rats under energy restriction showed an improvement in all the markers related to glycemic control, as well as increased phosphorylation of AS160 and protein expression of GLUT-4. In rats from RR group the results were similar to R group, with the exception of IRβ and Akt phosphorylation, which were increased. In conclusion, mild energy restriction is more efficient than intake of RSV within a standard balanced diet, and acts by means of a different mechanism from that of RSV. No additive effects between RSV and energy restriction were observed. © 2017 BioFactors, 43(3):371-378, 2017.

Olive oil in the prevention and management of type 2 diabetes mellitus: a systematic review and meta-analysis of cohort studies and intervention trials

Background/Objectives:

Olive oil (OO) as food is composed mainly of fatty acids and bioactive compounds depending from the extraction method. Both had been discussed as health promoting with still open questions. Thus, we conducted a meta-analysis to illustrate the impact of this food on type 2 diabetes (T2D) by investigating the association between OO intake and risk of T2D, and the effect of OO intake in the management of T2D.

Subjects/Methods:

Searches were performed in PubMed, Cochrane Library and google scholar. First, we conducted a random effect meta-analysis of prospective cohort studies and trials investigating the association between OO and risk of T2D. Second, a meta-analysis was performed to detect the effects of olive oil on glycemic control in patients with T2D.

Results:

Four cohort studies including 15 784 T2D cases and 29 trials were included in the meta-analysis. The highest OO intake category showed a 16% reduced risk of T2D (RR: 0.84; 95% CI: 0.77, 0.92) compared with the lowest. However, we observed evidence for a nonlinear relationship. In T2D patients OO supplementation resulted in a significantly more pronounced reduction in HbA1c (MD: −0.27% 95% CI: −0.37, −0.17) and fasting plasma glucose (MD: −0.44 mmol l⁻¹; 95% CI −0.66, −0.22) as compared with the control groups.

Conclusions:

This meta-analysis provides evidence that the intake of OO could be beneficial for the prevention and management of T2D. This conclusion regards OO as food, and might not been valid for single components comprising this food.

Effects of pterostilbene in brown adipose tissue from obese rats

In recent years, much attention has been paid by the scientific community to phenolic compounds as active biomolecules naturally present in foods. Pterostilbene is a resveratrol dimethylether derivative which shows higher bioavailability. The aim of the present study was to analyze the effect of pterostilbene on brown adipose tissue thermogenic markers in a model of genetic obesity, which shows reduced thermogenesis. The experiment was conducted with 30 Zucker (fa/fa) rats that were distributed in three experimental groups: control and two groups orally administered with pterostilbene at 15 and 30 mg/kg body weight/day for 6 weeks. Gene expression of uncoupling protein 1 (Ucp1), peroxisome proliferator-activated receptor γ co-activator 1 α (Pgc-1α), carnitine palmitoyl transferase 1b (Cpt1b), peroxisome proliferator-activated receptor α (Pparα), nuclear respiratory factor 1 (Nfr1), and cyclooxygenase-2 (Cox-2); protein expression of PPARα, PGC-1α, p38 mitogen-activated protein kinase (p38 MAPK), UCP1 and glucose transporter (GLUT4); and enzyme activity of CPT 1b and citrate synthase (CS) were assessed in interscapular brown adipose tissue. With the exception of Pgc-1α expression, all these parameters were significantly increased by pterostilbene administration. These results show for the first time that pterostilbene increases thermogenic and oxidative capacity of brown adipose tissue in obese rats. Whether these effects effectively contribute to the antiobesity properties of these compound needs further research.

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.