Role of sirtuins in obesity and osteoporosis: molecular mechanisms and therapeutic targets

The prevalence of obesity and osteoporosis (OP) represents a significant public health concern on a global scale. A substantial body of evidence indicates that there is a complex relationship between obesity and OP, with a correlation between the occurrence of OP and obesity. In recent years, sirtuins have emerged as a prominent area of interest in the fields of aging and endocrine metabolism. Among the various research avenues exploring the potential of sirtuins, the effects of these proteins on obesity and OP have garnered significant attention from numerous researchers. Sirtuins regulate energy balance and lipid balance, which in turn inhibit the process of adipogenesis. Additionally, sirtuins regulate the balance between osteogenic and osteoblastic activity, which protects against the development of OP. However, no study has yet provided a comprehensive discussion of the relationship between the three: sirtuins, obesity, and OP. This paper will therefore describe the relationship between sirtuins and obesity, the relationship between sirtuins and OP, and a discussion focusing on the possibility of treating OP caused by obesity by targeting sirtuins. This will be based on the common influences on the occurrence of obesity and OP (such as mesenchymal stem cells, gut microbiota, and insulin). Finally, the potential of SIRT1, an important member of sirtuins, in polyphenolic natural products for the treatment of obesity and OP will be presented. This will contribute to a better understanding of the interactions between sirtuins and obesity and bone, which will facilitate the development of new therapeutic strategies for obesity and OP in the future.

The Relationship Between Lycopene and Metabolic Diseases

Background: Metabolic syndrome, obesity, and type 2 diabetes are closely related. They are characterized by chronic inflammation and oxidative stress. Obesity is the most important risk factor for metabolic syndrome and type 2 diabetes. Metabolic syndrome is characterized by insulin resistance and elevated blood glucose levels, among other conditions. These disorders contribute to the development of type 2 diabetes, which can exacerbate other metabolic problems. Methods: Numerous studies indicate that diet and nutrients can have a major impact on preventing and treating these conditions. One such ingredient is lycopene. It is a naturally occurring carotenoid with a unique chemical structure. It exhibits strong antioxidant and anti-inflammatory properties due to its conjugated double bonds and its ability to neutralize reactive oxygen species. Its properties make lycopene indirectly affect many cellular processes. The article presents studies in animal models and humans on the activity of this carotenoid in metabolic problems. Results: The findings suggest that lycopene's antioxidant and anti-inflammatory activities make it a promising candidate for the prevention and treatment of metabolic syndrome, obesity, and type 2 diabetes. Conclusions: This review underscores the potential of lycopene as a beneficial dietary supplement in improving metabolic health and reducing the risk of associated chronic diseases. The conditions described are population diseases, so research into compounds with properties such as lycopene is growing in popularity.

Lycopene: A Potent Antioxidant with Multiple Health Benefits

Lycopene is a naturally occurring carotenoid predominantly found in tomatoes and tomato-based products. Like other phytochemicals, it exhibits health beneficial biological activities that can be exploited when it is used as a dietary supplement. In vitro and in vivo, lycopene has been demonstrated to mitigate oxidative stress-induced metabolic dysfunctions and diseases including inflammation, obesity, and diabetes mellitus. Lycopene has been shown to alleviate metabolic diseases that affect the bone, eye, kidney, liver, lungs, heart, and nervous system. This review presents the state of the art regarding lycopene's health benefits and its potential applications in health system delivery. Furthermore, lycopene's protective effects against toxins, safety in its use, and possible toxicity are explored.

Synergistic protection of quercetin and lycopene against oxidative stress via SIRT1-Nox4-ROS axis in HUVEC cells

Oxidative stress is a potential factor in the promotion of endothelial dysfunction. In this research, flavonoids (quercetin, luteolin) combined with carotenoids (lycopene, lutein), especially quercetin-lycopene combination (molar ratio 5:1), prevented the oxidative stress in HUVEC cells by reducing the reactive oxygen species (ROS) and suppressing the expression of NADPH oxidase 4 (Nox4), a major source of ROS production. RNA-seq analysis indicated quercetin-lycopene combination downregulated inflammatory genes induced by H₂O₂, such as IL-17 and NF-κB. The expression of NF-κB p65 was activated by H₂O₂ but inhibited by the quercetin-lycopene combination. Moreover, the quercetin and lycopene combination promoted the thermostability of Sirtuin 1 (SIRT1) and activated SIRT1 deacetyl activity. SIRT1 inhibitor EX-527 attenuated the inhibitory effects of quercetin, lycopene, and their combination on the expression of p65, Nox4 enzyme, and ROS. Quercetin-lycopene combination could interact with SIRT1 to inhibit Nox4 and prevent endothelial oxidative stress, potentially contributing to the prevention of cardiovascular disease.

Lycopene alleviates western diet-induced elevations in anthropometrical indices of obesity, adipose lipids, and other nutritional parameters

Objective: Given the unrelenting surge in the prevalence of obesity and the intensified efforts aimed at elucidating underlying mechanisms and proffering effective treatments, this study investigated the effects of lycopene on various anthropometrical indices of obesity. Methods: Thirty female Wistar rats were equally divided into two groups and fed either control diet or Western diet. After eight weeks, obese rats (fed Western diet) were divided into three groups (n=5); obese control received the vehicle, while the other two received lycopene (0.2 and 0.4 mg/kg body weight, respectively). Normal rats were grouped into three (n=5) and treated similarly. This treatment lasted for another two weeks, in addition to their respective diets. Afterwards, anthropometrical indices were taken. Results: The weight gain, adiposity index, abdominal and thoracic circumference, body mass index, and Lee index were significantly increased (p<0.05) in the obese rats compared to the normal control, by 108.3%, 102.1%, 81.5%, 97.6%, 47.4%, and 13.9%, respectively. The obese rats had significantly (p<0.05) higher adipose tissue lipid contents, daily feed (37.4%) and energy intake (66.0%), daily weight gain (108.3%), and feed efficiency (25.5%) compared to control. However, the treatment of obese rats with lycopene occasioned a dose-dependent reduction in the elevated anthropometrical and nutritional parameters. In addition, lycopene elicited significant reductions (p<0.05), ranging from 16-54%, in the adipose lipid contents. Conclusion: The data presented here illustrate the positive effects of lycopene on indices of obesity and other anthropometric parameters in obese female rats.

Efficient HPLC Separation on a Core-C30 Column with MS2 Characterization of Isomers, Derivatives and Unusual Carotenoids from Tomato Products

An efficient and rapid liquid chromatographic method was developed for the separation of carotenoids and their geometrical isomers in tomato products using a core C30 column of 2.6 μm particles with gradient elution of tert-butyl-methyl-ether in 2% water in methanol. Excellent separation of the major carotenoids such as lycopene, β-carotene and lutein as well as their geometrical isomers and oxygen-containing derivatives with resolution factors ranging between 0.78 and 4.0 and selectivity of 1.01-1.63 was achieved. Validation of the developed method met the acceptance criteria concerning linearity, recovery, precision and limit of detection and quantification. Calibrations were linear with correlation coefficient (R2) values between 0.9966 and 0.9999. The limit of detection and quantification values were found to be 0.008 and 0.017 and 0.029 and 0.056 μg/mL, respectively. Recovery of 94.3-99.9%, intraday precision of 1.81-4.45% and interday precision of 3.13-6.86% were obtained. The hyphenation of liquid chromatography with diode-array and mass spectrometry was helpful in the identification of the separated carotenoids particularly the unusual di-hydroxy cyclolycopene adduct and di-methoxy lycopene determined for the first time in tomato products. Commercially available kinds of tomato juice and ketchup were evaluated based on their carotenoid content.

Nutrition, Bioenergetics, and Metabolic Syndrome

According to the World Health Organization (WHO), the global nutrition report shows that whilst part of the world's population starves, the other part suffers from obesity and associated complications. A balanced diet counterparts these extreme conditions with the proper proportion, composition, quantity, and presence of macronutrients, micronutrients, and bioactive compounds. However, little is known on the way these components exert any influence on our health. These nutrients aiming to feed our bodies, our tissues, and our cells, first need to reach mitochondria, where they are decomposed into CO2 and H2O to obtain energy. Mitochondria are the powerhouse of the cell and mainly responsible for nutrients metabolism, but they are also the main source of oxidative stress and cell death by apoptosis. Unappropriated nutrients may support mitochondrial to become the Trojan horse in the cell. This review aims to provide an approach to the role that some nutrients exert on mitochondria as a major contributor to high prevalent Western conditions including metabolic syndrome (MetS), a constellation of pathologic conditions which promotes type II diabetes and cardiovascular risk. Clinical and experimental data extracted from in vitro animal and cell models further demonstrated in patients, support the idea that a balanced diet, in a healthy lifestyle context, promotes proper bioenergetic and mitochondrial function, becoming the best medicine to prevent the onset and progression of MetS. Any advance in the prevention and management of these prevalent complications help to face these challenging global health problems, by ameliorating the quality of life of patients and reducing the associated sociosanitary burden.

The Antioxidant Activities of Betula etnensis Rafin. Ethanolic Extract Exert Protective and Anti-diabetic Effects on Streptozotocin-Induced Diabetes in Rats

Pathophysiological mechanisms correlating diabetes mellitus with associated complications are still not completely clear, even though oxidative stress seems to play a pivotal role. Literature data suggest that cell damages induced by hyperglycemia, although multifactorial, have a common pathway in oxidative/nitrosative stress. The present study evaluated the effects of Betula etnensis Raf. bark extract, a plant belonging to the Betulaceae family endemic to Sicily, on oxidative stress and in preventing and/or retarding diabetes-associated complications in streptozotocin diabetic rats treated with the extract at dose of 0.5 g/kg body weight per day for 28 consecutive days. The extract administration significant decreased food and water intake, fasting blood glucose, weight loss and polyuria, compared with untreated diabetic animals. Furthermore, oxidative stress markers particularly, lipid hydroperoxides (LOOH) and nitrite/nitrate levels, non-proteic thiol groups (RSH), γ-glutamyl-cysteine-synthetase (γ-GCS) activities and expression, heme oxygenase-1 (HO-1), endothelial and inducible nitric oxide synthases (i-NOS e-NOS) expression, significantly changed by streptozocin treatment, were markedly restored both in plasma and tissues together with nuclear sirtuins activity (Sirt1). Results suggested that B. etnensis bark alcoholic extract is able to counteract oxidative stress and to ameliorate some general parameters related to diabetes.

Effect of lycopene on pain facilitation and the SIRT1/mTOR pathway in the dorsal horn of burn injury rats

To explore the effect of intrathecal injection of lycopene on pain facilitation, glial activation, and the SIRT1/mTOR pathway in the dorsal horn of rats with burn injury pain (BIP). Here we found that the mechanical pain threshold increased in the lycopene group compared with that of the control group, (P < 0.05). Compared with expression in the sham group, mTOR, pS6, p4EBP, GFAP, and Iba-1 decreased and SIRT1 increased in the lycopene group (P < 0.01). Glial activation in the spinal dorsal horn of BIP rats was alleviated by lycopene (P < 0.01). The SIRT1 and mTOR were mainly distributed in neurons in the spinal dorsal horn in the BIP model. Intrathecal injection of 3-MA (a mTOR agonist) or EX-527 (an inhibitor of Sirt1) partially antagonized lycopene-induced analgesia. Intrathecal injection of rapamycin (an mTOR inhibitor) or SRT1720 (an agonist of Sirt1) induced analgesia in BIP rats. 3-MA abrogated the SRT1720-induced analgesic effects. The present data indicated that the SIRT1/mTOR pathway changed in the spinal dorsal horn of BIP rats; Lycopene alleviated the pain sensitization of BIP rats by regulating the SIRT1/mTOR pathway and glial activation in the spinal dorsal horn.

Systemic and Adipose Tissue Redox Status in Sprague-Dawley Rats Fed Normal- and High-Fat Diets Supplemented with Lycopene

Dietary patterns high in fat influence local and systemic oxidative stress through adipose tissue (AT) accrual and increased reactive oxygen species generation. Lycopene, a carotenoid with antioxidant functionality, may mitigate excess oxidative stress, yet the lipophilic nature of this compound may limit its functionality if sequestered by AT. Thus, it is critical to elucidate whether lycopene's efficacy is limited based on adiposity. The purpose of this study was to investigate the influence of lycopene-supplemented normal- and high-fat diets on systemic and AT redox status. Male Sprague-Dawley rats (n = 18) were fed a 30% normal-fat (NFD) or 60% high-fat (HFD) purified diet supplemented with 100 mg of lycopene/day. Body weight and visceral AT mass, as well as serum and AT lycopene, lipid peroxides, and antioxidant capacity (AC), were assessed after 3, 7, and 10 weeks of supplementation. At week 10, AT mass was significantly higher (P = .028) in the HFD group, yet there were no significant differences in serum or AT lycopene concentrations or lipid peroxides between groups. Additionally, AT in the HFD group exhibited significantly greater lipophilic AC (27.6% higher, P = .031). Results suggest that excess adiposity did not negatively influence circulating lycopene, nor did it limit its antioxidant functionality.

Lycopene in protection against obesity and diabetes: A mechanistic review

Lycopene, a natural pigment that mainly exists in the mature fruit of tomatoes, has gained increasing attention due to its protective effects against obesity and diabetes. The aim of this review is to summarize the potential mechanisms in which lycopene exerts protection against obesity and diabetes, along with highlighting its bioavailability, synthesis and safety. Literature sources used in this review were from the PubMed Database, China Knowledge Resource Integrated Database, China Science and Technology Journal Database, National Science and Technology Library, Wanfang Data, and the Web of Science. For the inquiries, keywords such as lycopene, properties, synthesis, diabetes, obesity, and safety were used in various combinations. About 200 articles and reviews were evaluated. Lycopene exhibits anti-obesity and anti-diabetic activities in different organs and/or tissues, including adipose tissue, liver, kidney, pancreas, brain, ovaries, intestine, and eyes. The underlying mechanism may be attributed to its anti-oxidant and anti-inflammatory properties and through its ability to regulate of AGE/RAGE, JNK/MAPK, PI3K/Akt, SIRT1/FoxO1/PPARγ signaling pathways and AchE activity. The epidemiological investigations support that lycopene consumption may contribute to lowering the risk of obesity and diabetes. The cis-isomers of lycopene are more bioavailable and better absorbed than trans-lycopene, and mainly distribute in liver and adipose tissue. Lycopene exhibits a good margin of safety and can be obtained by plant extraction, chemical synthesis and microbial fermentation. In summary, lycopene consumption beneficially contributes to protecting against diabetes and obesity in animal studies and epidemiological investigations, which supports the potential of this compound as a preventive/therapeutic agent against these disorders. Well-designed, prospective clinical studies are warranted to evaluate the potential therapeutic effect of lycopene against common metabolic diseases.

Carotenoids and carotenoid conversion products in adipose tissue biology and obesity: Pre-clinical and human studies

Antiobesity activities of carotenoids and carotenoid conversion products (CCPs) have been demonstrated in pre-clinical studies, and mechanisms behind have begun to be unveiled, thus suggesting these compounds may help obesity prevention and management. The antiobesity action of carotenoids and CCPs can be traced to effects in multiple tissues, notably the adipose tissues. Key aspects of the biology of adipose tissues appear to be affected by carotenoid and CCPs, including adipogenesis, metabolic capacities for energy storage, release and inefficient oxidation, secretory function, and modulation of oxidative stress and inflammatory pathways. Here, we review the connections of carotenoids and CCPs with adipose tissue biology and obesity as revealed by cell and animal intervention studies, studies addressing the role of endogenous retinoid metabolism, and human epidemiological and intervention studies. We also consider human genetic variability influencing carotenoid and vitamin A metabolism, particularly in adipose tissues, as a potentially relevant aspect towards personalization of dietary recommendations to prevent or manage obesity and optimize metabolic health. This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.

Randomised Clinical Trial: Calorie Restriction Regimen with Tomato Juice Supplementation Ameliorates Oxidative Stress and Preserves a Proper Immune Surveillance Modulating Mitochondrial Bioenergetics of T-Lymphocytes in Obese Children Affected by Non-Alcoholic Fatty Liver Disease (NAFLD)

Fatty liver disease is a serious complication of childhood obesity. Calorie-restricted regimen (RCR) is one of the effective therapy for this condition. Aim of the study was to evaluate the effect of lycopene-rich tomato sauce with oregano and basil extracts in obese children with fatty liver on RCR. 61 obese children with fatty liver were enrolled, 52 completed the study. A randomized cross over clinical trial was performed. Participants were assigned to RCR alone or with a supplement of lycopene-rich tomato juice for 60 days; subsequently, the groups were switched to the alternative regimen for the next 60 days. Reduction in BMI, HOMA-IR, cholesterol, triglycerides, liver size, and steatosis was more profound in tomato-supplemented group. Leptin decreased in both groups whereas adiponectin raised only after tomato supplementation. RCR is associated with the impaired engagement of T-cells glycolysis and proliferation, tomato-supplementation resulted in glycolytic metabolic activation of T-cells. Tomato juice ameliorates glucose and lipid metabolism in obese children, improve oxidative and inflammatory state and modulates the mitochondrial metabolism of T-cells contributing to a maintenance of a proper immune surveillance in children, impaired by RCR. The addition of tomato to RCR could be considered a protective and preventive support to obese child.

Protective Effect of Tomato-Oleoresin Supplementation on Oxidative Injury Recoveries Cardiac Function by Improving β-Adrenergic Response in a Diet-Obesity Induced Model

The system redox imbalance is one of the pathways related to obesity-related cardiac dysfunction. Lycopene is considered one of the best antioxidants. The aim of this study was to test if the tomato-oleoresin would be able to recovery cardiac function by improving β-adrenergic response due its antioxidant effect. A total of 40 animals were randomly divided into two experimental groups to receive either the control diet (Control, n = 20) or a high sugar-fat diet (HSF, n = 20) for 20 weeks. Once cardiac dysfunction was detected by echocardiogram in the HSF group, animals were re- divided to begin the treatment with Tomato-oleoresin or vehicle, performing four groups: Control (n = 6); (Control + Ly, n = 6); HSF (n = 6) and (HSF + Ly, n = 6). Tomato oleoresin (10 mg lycopene/kg body weight (BW) per day) was given orally every morning for a 10-week period. The analysis included nutritional and plasma biochemical parameters, systolic blood pressure, oxidative parameters in plasma, heart, and cardiac analyses in vivo and in vitro. A comparison among the groups was performed by two-way analysis of variance (ANOVA). Results: The HSF diet was able to induce obesity, insulin-resistance, cardiac dysfunction, and oxidative damage. However, the tomato-oleoresin supplementation improved insulin-resistance, cardiac remodeling, and dysfunction by improving the β-adrenergic response. It is possible to conclude that tomato-oleoresin is able to reduce the oxidative damage by improving the system’s β-adrenergic response, thus recovering cardiac function.

Lycopene Modulates Pathophysiological Processes of Non-Alcoholic Fatty Liver Disease in Obese Rats

Background: The higher consumption of fat and sugar are associated with obesity development and its related diseases such as non-alcoholic fatty liver disease (NAFLD). Lycopene is an antioxidant whose protective potential on fatty liver degeneration has been investigated. The aim of this study was to present the therapeutic effects of lycopene on NAFLD related to the obesity induced by a hypercaloric diet. Methods: Wistar rats were distributed in two groups: Control (Co, n = 12) and hypercaloric (Ob, n = 12). After 20 weeks, the animals were redistributed into the control group (Co, n = 6), control group supplemented with lycopene (Co+Ly, n = 6), obese group (Ob, n = 6), and obese group supplemented with lycopene (Ob+Ly, n = 6). Ob groups also received water + sucrose (25%). Animals received lycopene solution (10 mg/kg/day) or vehicle (corn oil) via gavage for 10 weeks. Results: Animals which consumed the hypercaloric diet had higher adiposity index, increased fasting blood glucose, hepatic and blood triglycerides, and also presented in the liver macro and microvesicular steatosis, besides elevated levels of tumor necrosis factor-α (TNF-α). Lycopene has shown therapeutic effects on blood and hepatic lipids, increased high-density lipoprotein cholesterol (HDL), mitigated TNF-α, and malondialdehyde (MDA) and further improved the hepatic antioxidant capacity. Conclusion: Lycopene shows therapeutic potential to NAFLD.

Lycopene protects against pressure overload-induced cardiac hypertrophy by attenuating oxidative stress

Oxidative stress is considered an important pathogenic process of cardiac hypertrophy. Lycopene is a kind of carotenoid antioxidant that protects the cardiovascular system, so we hypothesized that lycopene might inhibit cardiac hypertrophy by attenuating oxidative stress. Phenylephrine and pressure overload were used to set up the hypertrophic models in vitro and in vivo respectively. Our data revealed that treatment with lycopene can significantly block pressure overload-induced cardiac hypertrophy in in vitro and in vivo studies. Further studies demonstrated that lycopene can reverse the increase in reactive oxygen species (ROS) generation during the process of hypertrophy and can retard the activation of ROS-dependent pro-hypertrophic MAPK and Akt signaling pathways. In addition, protective effects of lycopene on the permeability transition pore opening in neonatal cardiomyocytes were observed. Moreover, we demonstrated that lycopene restored impaired antioxidant response element (ARE) activity and activated ARE-driven expression of antioxidant genes. Consequently, our findings indicated that lycopene inhibited cardiac hypertrophy by suppressing ROS-dependent mechanisms.

Let food be your medicine: nutraceutical properties of lycopene

In this review, we highlight research and clinical trials involving lycopene and its impact on human health.

FoxO1-miRNA interacting networks as potential targets for mitochondrial diseases

Mitochondrial homeostasis is important for the health and well-being of organ systems and organisms. Mitochondrial dysfunction is known to be the cause and consequence of metabolic diseases, including obesity, diabetes, cancer, neurodegeneration, cerebrovascular, and cardiovascular disease. For cardiovascular tissue, which relies mostly on oxidative phosphorylation, the role of mitochondria is inevitable. Rather than being biomarkers of mitochondrial health, miRNAs are now known as bioregulators of this important feature. Recent studies have shown a close interaction between Forkhead box other 1 (FoxO1) transcription factors and miRNAs in the cardiovascular system. These interactions have also been shown to regulate mitochondrial homeostasis. In this review, I highlight how understanding FoxO1 and miRNA interacting networks could enable us to limit mitochondrial dysfunction and associated pathologies.

Phenolic Plant Extracts Induce Sirt1 Activity and Increase Antioxidant Levels in the Rabbit's Heart and Liver

Background

Several dietary phytochemicals potentially regulate the equilibrium between oxidant and antioxidant species. The aim of this study was to evaluate the effects of Lippia citriodora, Raphanus sativus, and Solanum lycopersicum on blood parameters, oxidative/antioxidant status, and SIRT1 activity in the rabbit's heart and liver.

Methods

Twenty rabbits were divided into 4 groups of 5 animals each. The control group (CN) received a feed without any additives. One intervention group received a supplement containing verbascoside (VB), another Raphanus sativus extract (RAP), and lastly lycopene (LYC). Oxidant-antioxidant parameters and SIRT1 activity were measured in plasma and in the heart and liver, respectively.

Results

The treatment with VB, RAP, and LYC resulted in a marked improvement in the blood lipid and glycaemic profile in respect to CN. VB was the most effective, but all three plant extracts induced a significant reduction in oxidant parameters as well as an increase in antioxidant tissue activity and vitamin A and E levels. SIRT1 activity was significantly increased in both VB and LYC compared to CN, but the increased levels in the VB group were far the highest. The multivariate analysis suggests that the benefits of VB, particularly the antiglycaemic and antioxidant effects, might be mediated by increasing SIRT1 activity.

Tomato Powder Inhibits Hepatic Steatosis and Inflammation Potentially Through Restoring SIRT1 Activity and Adiponectin Function Independent of Carotenoid Cleavage Enzymes in Mice

SCOPE

Beta-carotene-15,15'-oxygenase (BCO1) and beta-carotene-9',10'-oxygenase (BCO2) metabolize lycopene to biologically active metabolites, which can ameliorate nonalcoholic fatty liver disease (NAFLD). We investigate the effects of tomato powder (TP containing substantial lycopene (2.3 mg/g)) on NAFLD development and gut microbiome in the absence of both BCO1 and BCO2 in mice.

METHOD AND RESULTS

BCO1^-/- /BCO2^-/- double knockout mice were fed a high fat diet (HFD) alone (n = 9) or with TP feeding (n = 9) for 24 weeks. TP feeding significantly reduced pathological severity of steatosis and hepatic triglyceride levels in BCO1^-/- /BCO2^-/- mice (p < 0.04 vs HFD alone). This was associated with increased SIRT1 activity, nicotinamide phosphoribosyltransferase expression and AMP-activated protein kinase phosphorylation, and subsequently decreased lipogenesis, hepatic fatty acid uptake, and increasing fatty acid β-oxidation (p < 0.05). TP feeding significantly decreased mRNA expression of proinflammatory genes (tnf-α, il-1β, and il-6) in both liver and mesenteric adipose tissue, which were associated with increased plasma adiponectin and hepatic adiponectin receptor-2. Multiplexed 16S rRNA gene sequencing was performed using DNA extracted from cecum fecal samples. TP feeding increased microbial richness and decreased relative abundance of the genus Clostridium.

CONCLUSION

Dietary TP can inhibit NAFLD independent of carotenoid cleavage enzymes, potentially through increasing SIRT1 activity and adiponectin production and decreasing Clostridium abundance.

A global perspective on FOXO1 in lipid metabolism and lipid-related diseases

Lipid metabolism is a complex physiological process that is involved in nutrient adjustment, hormone regulation, and homeostasis. An unhealthy lifestyle and chronic nutrient overload can cause lipid metabolism disorders, which may lead to serious lipid-related diseases, including obesity, non-alcoholic fatty liver disease (NAFLD), and type 2 diabetes mellitus (T2DM). Therefore, tools for preventing dysfunctional lipid metabolism are urgently needed. The transcription factor forkhead box protein O1 (FOXO1) is involved in lipid metabolism and plays a critical role in the development of lipid-related diseases. In this review, we provide a global perspective on the role of FOXO1 in lipid metabolism and lipid-related diseases. The information included here may be useful for the design of future studies and advancing investigations of FOXO1 as a therapeutic target.

Combinations of bio-active dietary constituents affect human white adipocyte function in-vitro

Background

Specific bio-active dietary compounds modulate numerous metabolic processes in adipose tissue (AT), including pre-adipocyte proliferation and differentiation. AT dysfunction, rather than an increased fat mass per se, is strongly associated with the development of insulin resistance and is characterized by impaired adipogenesis, hypertrophic adipocytes, inflammation, and impairments in substrate metabolism. A better understanding of mechanisms underlying AT dysfunction may provide new strategies for the treatment of obesity-associated metabolic diseases. Here we evaluated the role of (all-E)-lycopene (Lyc), eicosapentaenoic acid (EPA) or trans-resveratrol (Res) and combinations thereof on human white adipocyte function.

Methods

In-vitro differentiating human pre-adipocytes were treated with EPA, Lyc and Res or their combinations for 14 days. The effects on intracellular lipid droplet (LD) accumulation, secreted anti- and pro-inflammatory cyto-/adipokines (e.g. adiponectin, IL-6, IL-8/CXCL-8 and MCP-1/CCL2) and on gene expression of markers of adipocyte differentiation and substrate metabolism (e.g. PPAR-gamma, C/EBP-alpha, GLUT-4, FAS, ATGL, HSL, and PLIN-1) were measured by fluorescent microscopy (Cellomics™), multi-parametric LiquiChip® technology and quantitative RT-PCR, respectively.

Results

Treatment of differentiating adipocytes for 14 days with the combination of Lyc/Res and EPA/Res resulted in significantly inhibited LD formation (~ -25 and -20%, respectively) compared to the effects of the single compounds. These morphological changes were accompanied by increased mRNA levels of the adipogenic marker PPAR-gamma and the lipase ATGL and by decreased expression levels of lipogenic markers (LPL, FAS, GLUT-4) and the LD-covering protein PLIN-1. In addition, a blunted adipocyte secretion of pro-inflammatory cytokines (IL-6 and MCP-1) and adiponectin was observed following treatment with these compounds.

Conclusion

The combination of the dietary bio-actives Lyc and EPA with Res might influence adipocyte function by affecting the balance between adipogenic, lipogenic and lipolytic gene expression, resulting in a reduced LD storage and a less inflammatory secretion profile. Taken together, our results indicate that combinations of dietary compounds may be beneficial for the prevention and treatment of metabolic disorders via effects on human white adipocyte function.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-016-0143-5) contains supplementary material, which is available to authorized users.

Dietary regulation of adiponectin by direct and indirect lipid activators of nuclear hormone receptors

Adiponectin is an adipokine mainly secreted by adipocytes that presents antidiabetic, anti-inflammatory, and antiatherogenic functions. Therefore, modulation of adiponectin expression represents a promising target for prevention or treatment of several diseases including insulin resistance and type II diabetes. Pharmacological agents such as the nuclear hormone receptor synthetic agonists like peroxisome proliferator activated receptor γ agonists are of particular interest in therapeutic strategies due to their ability to increase the plasma adiponectin concentration. Nutritional approaches are also of particular interest, especially in primary prevention, since some active compounds of our diet (notably vitamins, carotenoids, or other essential nutrients) are direct or indirect lipid-activators of nuclear hormone receptors and are modifiers of adiponectin expression and secretion. The aim of the present review is to summarize current knowledge about the nutritional regulation of adiponectin by derivatives of active compounds naturally present in the diet acting as indirect or direct activators of nuclear hormone receptors.

Isocaloric Pair-Fed High-Carbohydrate Diet Induced More Hepatic Steatosis and Inflammation than High-Fat Diet Mediated by miR-34a/SIRT1 Axis in Mice

To investigate the different effects of isocaloric high-fat diet (HFD) and high-carbohydrate diet (HCD) on hepatic steatosis and the underlying mechanisms, especially the role of microRNA-34a/silent information regulator T1 (SIRT1) axis, C57BL/6J mice (n = 12/group) were isocaloric pair-fed with Lieber-DeCarli liquid diet containing either high fat (HFLD) or high carbohydrate (HCLD) for 16 weeks. As compared to the HFLD fed mice, despite the similar final body weights, HCLD feeding: (1) induced more severe hepatic steatosis; (2) up-regulated hepatic expression of miR-34a accompanied with significant decrease of SIRT1 and nicotinamide phosphoribosyltransferase (NAMPT), SIRT1 activity and phosphorylation of AMPK; (3) up-regulated de novo lipogenesis (DNL) related proteins expression (ACC, SCD1), and down-regulated expressions of miR-122, miR-370 and miR-33; (4) decreased mRNA expressions of genes Cpt1, Pparα and Pgc1α related to fatty acid oxidation; (5) increased hepatic total cholesterol concentration and decreased expression of cholesterol metabolism related genes Abcg5, Abcg8, Abcg11, Cyp7a1 and Cyp8b1; and (6) induced higher hepatic inflammatory response accompanied with significant increased mRNA expressions of Il1β, Tnfα and Mcp1. Thus, isocaloric HCLD feeding induced greater severity in hepatic steatosis and inflammatory response than HFLD feeding, potentially through miR-34a/SIRT1 axis mediated promotion of DNL, inhibition of fatty acid oxidation and cholesterol metabolism.

Tomato (Lycopersicon esculentum) Supplementation Induces Changes in Cardiac miRNA Expression, Reduces Oxidative Stress and Left Ventricular Mass, and Improves Diastolic Function

The aim of this study was to evaluate the effects of tomato supplementation on the normal rat heart and the role of oxidative stress in this scenario. Male Wistar rats were assigned to two groups: a control group (C; n = 16), in which animals received a control diet + 0.5 mL of corn oil/kg body weight/day, and a tomato group (T; n = 16), in which animals received a control diet supplemented with tomato +0.5 mL of corn oil/kg body weight/day. After three months, morphological, functional, and biochemical analyses were performed. Animals supplemented with tomato had a smaller left atrium diameter and myocyte cross-sectional area (CSA) compared to the control group (C group: 474 (415–539); T group: 273 (258–297) µm²; p = 0.004). Diastolic function was improved in rats supplemented with tomato. In addition, lipid hydroperoxide was lower (C group: 267 ± 46.7; T group: 219 ± 23.0 nmol/g; p = 0.039) in the myocardium of rats supplemented with tomato. Tomato intake was also associated with up-regulation of miR-107 and miR-486 and down-regulation of miR-350 and miR-872. In conclusion, tomato supplementation induces changes in miRNA expression and reduces oxidative stress. In addition, these alterations may be responsible for CSA reduction and diastolic function improvement.