The effects of resveratrol on lipid profiles and liver enzymes in patients with metabolic syndrome and related disorders: a systematic review and meta-analysis of randomized controlled trials

The therapeutic potential of typical plant-derived compounds for the management of metabolic disorders

Obesity and Type 2 diabetes are prevalent metabolic dysfunctions that present significant health challenges worldwide. Available cures for these ailments have constraints with accompanying unwanted effects that persistently exist. Compounds originated from plants have recently been introduced as hopeful remedies to treat metabolic disorders because of their diverse pharmacological activities. This detailed observation gives an introduction into the treatment capacity of plant-derived compounds regarding metabolic syndromes while analyzing various groups alongside their performance in this field despite unique mechanisms designed by nature itself. Interestingly, this study provides some examples including curcumin, resveratrol, quercetin, berberine, epigallocatechin gallate (EGCG), and capsaicin, which highlights potential therapeutic impacts for future testing. However, current clinical trials inspecting human studies investigating efficacies concerning metabolism challenge present limitations. Finally, the review weighs up bad reactions possibly inflicted after administering plant-originated materials though suggestive insights will be provided later. Above all, it outlines the chance to identify novel therapies encapsulated within natural substances based upon recent developments could hold significant promise toward managing misplaced metabolisms globally.

Resveratrol and Gut Microbiota Synergy: Preventive and Therapeutic Effects

The role of an imbalanced high-fat diet in the pathophysiology of common chronic noncommunicable diseases has been known for years. More recently, the concept of 'gut microbiota' and the interaction between their composition and gut metabolites produced from the intake of dietary products have gained the focus of researchers, mostly from the perspective of the prevention of cardiovascular and metabolic disorders, which are still the leading cause of death globally. The aim of this work is to highlight the health benefits of the interaction between resveratrol (RSV), red grape polyphenol, and gut microbiota, through aspects of their therapeutic and preventive potentials. Since changed microbiota (mostly as a consequence of antibiotic overuse) contribute to the persistence of post ('long')-COVID-19 symptoms, these aspects will be covered too. Data were obtained from the electronic databases (MedLine/PubMed), according to specific keywords regarding the protective role of resveratrol, the gut microbiota, and their synergy. RSV exerts beneficial properties in the modulation of cardiovascular, metabolic, and post-COVID-19-related disorders. In healthy individuals, it maintains an ergogenic capacity, prevents oxidative stress, and modulates the inflammatory response. Overall, it improves quality of life. The RSV-gut-microbiota interaction is beneficial in terms of maintaining human health. Along with physical activity, it is key for the prevention of chronic noncommunicable diseases.

Targeting Oxidative Stress with Polyphenols to Fight Liver Diseases

Reactive oxygen species (ROS) are important second messengers in many metabolic processes and signaling pathways. Disruption of the balance between ROS generation and antioxidant defenses results in the overproduction of ROS and subsequent oxidative damage to biomolecules and cellular components that disturb cellular function. Oxidative stress contributes to the initiation and progression of many liver pathologies such as ischemia-reperfusion injury (LIRI), non-alcoholic fatty liver disease (NAFLD), and hepatocellular carcinoma (HCC). Therefore, controlling ROS production is an attractive therapeutic strategy in relation to their treatment. In recent years, increasing evidence has supported the therapeutic effects of polyphenols on liver injury via the regulation of ROS levels. In the current review, we summarize the effects of polyphenols, such as quercetin, resveratrol, and curcumin, on oxidative damage during conditions that induce liver injury, such as LIRI, NAFLD, and HCC.

Lipid-Lowering Nutraceuticals for an Integrative Approach to Dyslipidemia

Dyslipidemia is a treatable risk factor for atherosclerotic cardiovascular disease that can be addressed through lifestyle changes and/or lipid-lowering therapies. Adherence to statins can be a clinical challenge in some patients due to statin-associated muscle symptoms and other side effects. There is a growing interest in integrative cardiology and nutraceuticals in the management of dyslipidemia, as some patients desire or are actively seeking a more natural approach. These agents have been used in patients with and without established atherosclerotic cardiovascular disease. We provide an updated review of the evidence on many new and emerging nutraceuticals. We describe the mechanism of action, lipid-lowering effects, and side effects of many nutraceuticals, including red yeast rice, bergamot and others.

The effect of resveratrol supplementation on biomarkers of liver health: A systematic review and meta-analysis of randomized controlled trials

This study aimed to evaluate the effect of resveratrol on liver biomarkers in adult participants, using systematic review and meta-analysis of randomized controlled trials. PubMed, Scopus, Web of Science and Cochran Library was searched, up to October 2021. The pooled effects were calculated using a random-effects model and expressed as weighted mean difference and 95% confidence interval. The methodological quality of studies as well as certainty of evidence were assessed by standard tools. Thirty-seven relevant trials were found. Although overall analysis found no significant change, subgroup analysis showed a significant improvement in alanine aminotransferase (ALT; -7.79 U/L) and glutamyl transferase (-6.0 U/L) in patients with liver disorders, and ALT (-2.22 U/L) in younger adults; however, high-dose supplementation (>1,000 mg/day) appeared to increase alkaline phosphatase concentration (+5.07 U/L). ALT also increased in older adults (+2.33 U/L) following resveratrol supplementation. We found resveratrol did not have a significant effect on liver health in the general population. However, resveratrol could be effective in patients with liver disorders. Our findings also suggest that high-dose resveratrol administration and supplementation in older adults should be performed with caution. Further high-quality clinical trials are also needed to firmly establish the clinical efficacy of resveratrol.

The effects of phytochemicals on serum triglycerides in subjects with hypertriglyceridemia: A systematic review of randomized controlled trials

This systematic review aimed to evaluate the efficacy of phytochemicals on lipid parameters in patients with hypertriglyceridemia (HTG). A comprehensive search was performed in PubMed/Medline, Scopus, ISI Web of Science, and Google Scholar from inception up to October 2021 to recognize randomized controlled trials (RCTs) assessing the effects of phytochemicals on lipid profiles in patients with HTG. Forty-eight RCTs including 53 arms and comprising 3,478 HTG patients met the eligibility criteria. Phytochemicals significantly reduced the serum levels of triglycerides in 32 out 53 arms, total cholesterol in 22 out of 51, low-density lipoprotein cholesterol in 21 out of 48, very low-density lipoprotein cholesterol in 1 out of 5, apolipoprotein B in 2 out of 4, and lipoprotein(a) levels in 2 out of 4 arms. Furthermore, phytochemicals supplementation increased the levels of high-density lipoprotein cholesterol in 15 out of 48 arms. In brief, phytochemicals supplementation might have beneficial effects on HTG. In most of the studies, phytochemicals had a favorable effect on at least one of the lipid parameters.

δ-Tocotrienol in Combination with Resveratrol Improves the Cardiometabolic Risk Factors and Biomarkers in Patients with Metabolic Syndrome: A Randomized Controlled Trial

Background: Metabolic syndrome (MetS) is a cluster of central obesity, hypertension, hyperglycemia, and dyslipidemia. It is a global health issue with an increased risk of cardiovascular disease. Recently, a few natural products have been reported with promising anti-inflammatory and antioxidative effects. We aimed to evaluate the impact of δ-tocotrienol and resveratrol mixture (TRM) supplementation on cardiometabolic risk factors and biomarkers in patients with MetS. Methods: A randomized controlled trial was conducted at the hospitals of National University of Medical Sciences Rawalpindi, Pakistan. A total of 82 patients with MetS aged 18-60 years were enrolled based on International Diabetes Federation-2005 diagnostic criteria and randomly grouped into TRM (n = 41) and placebo (n = 41). Patients in the TRM group were given a 400 mg capsule (δ-tocotrienol 250 mg; resveratrol 150 mg), and a placebo (cellulose 400 mg) twice daily for 24 weeks. The biochemical tests were analyzed on ADVIA 1800 Chemistry^® analyzer and inflammatory biomarkers by ELISA methods. Results: In the TRM group, a significant reduction in waist circumference, blood pressure, mean (95% confidence interval) of fasting plasma glucose -0.15 mmol/L (-0.22 to -0.08), serum triglyceride -0.32 mmol/L (-0.47 to -0.17), and increment in high-density lipoprotein cholesterol were observed as compared with placebo. TRM supplementation also improved biomarkers: high-sensitive C-reactive protein -0.61 mg/L (-0.89 to -0.33), interleukin-6-1.99 pg/mL (-2.50 to -1.48), tumor necrosis factor-α -2.19 pg/mL (-2.55 to -1.83), malondialdehyde -0.48 μmol/L (-0.65 to -0.30), and total antioxidant capacity 1.71 U/mL (1.29 to 2.13). Conclusion: TRM supplementations improved cardiometabolic risk factors and biomarkers of inflammation and oxidative stress without any significant side effects in the patients with MetS. Clinical Trials Registry: The clinical trial was registered in Sri Lanka Clinical Trials Registry (https://slctr.lk/trials/slctr-2019-021).

Screening for MAFLD: who, when and how?

Metabolic-associated fatty liver disease (MAFLD) is a highly prevalent disease with increasing prevalence worldwide. Currently, no universal screening methods have been standardized, even when this disease poses a major health burden. MAFLD as a spectrum of diseases can range from simple steatosis, and steatohepatitis to fibrosis and hepatocellular carcinoma. Its extra-hepatic manifestations are vast and include cardiovascular diseases, extra-hepatic malignancies, cognitive and respiratory alterations. Given its extensive damage targets as well as its high prevalence, timely identification of the high-risk population presenting metabolic dysfunction should undergo universal non-invasive screening methods, which can be carried out through blood tests, easy and effective imaging techniques, such as ultrasound, score calculation and general clinical information brought together from primary patient-physician contact.

Nutritional supplements improve cardiovascular risk factors in overweight and obese patients: A Bayesian network meta-analysis

Background

Overweight and obesity are considered as one of the major risk factors for cardiovascular diseases (CVD). At present, many studies have proved that multiple nutritional supplements play an active role in metabolic diseases. However, the comparative efficacy of different nutritional supplements in improving indicators of cardiometabolic risk in obese and overweight patients is uncertain.

Methods

Cochrane Library, PubMed, Embase, and Web of Science were searched for the period from January 1990 to March 2022. A random-effect model was built in the Bayesian network meta-analysis. The surface under the cumulative ranking analysis (SUCRA) and clustering rank analysis was performed for ranking the effects.

Results

The study included 65 RCTs with 4,241 patients. In terms of glucose control, probiotic was more conductive to improve FBG (MD: -0.90; 95%CrI: -1.41 to -0.38), FINS (MD: -2.05; 95%CrI: -4.27 to -0.02), HOMA-IR (MD: -2.59; 95%CI -3.42 to -1.76). Probiotic (MD: -11.15, 95%CrI -22.16 to -1.26), omega-3 (MD: -9.45; 95%CrI: -20.69 to -0.93), VD (MD: -17.86; 95%CrI: -35.53 to -0.27), and probiotic +omega-3 (MD: 5.24; 95%CrI: 0.78 to 9.63) were beneficial to the improvement of TGs, TC and HDL-C, respectively. The SUCRA revealed that probiotic might be the best intervention to reduce FBG, FINS, HOMA-IR; Simultaneously, α-lipoic acid, VD, and probiotic + omega-3 might be the best intervention to improve TGs, TC, and HDL-C, respectively. Cluster-rank results revealed probiotic had the best comprehensive improvement effect on glucose metabolism, and probiotic + omega-3 may have a better comprehensive improvement effect on lipid metabolism (cluster-rank value for FBG and FINS: 3290.50 and for TGs and HDL-C: 2117.61).

Conclusion

Nutritional supplementation is effective on CVD risk factors in overweight and obese patients. Probiotic supplementation might be the best intervention for blood glucose control; VD, probiotic + omega-3 have a better impact on improving lipid metabolism. Further studies are required to verify the current findings.

American Association of Clinical Endocrinology Clinical Practice Guideline: Developing a Diabetes Mellitus Comprehensive Care Plan-2022 Update

OBJECTIVE

The objective of this clinical practice guideline is to provide updated and new evidence-based recommendations for the comprehensive care of persons with diabetes mellitus to clinicians, diabetes-care teams, other health care professionals and stakeholders, and individuals with diabetes and their caregivers.

METHODS

The American Association of Clinical Endocrinology selected a task force of medical experts and staff who updated and assessed clinical questions and recommendations from the prior 2015 version of this guideline and conducted literature searches for relevant scientific papers published from January 1, 2015, through May 15, 2022. Selected studies from results of literature searches composed the evidence base to update 2015 recommendations as well as to develop new recommendations based on review of clinical evidence, current practice, expertise, and consensus, according to established American Association of Clinical Endocrinology protocol for guideline development.

RESULTS

This guideline includes 170 updated and new evidence-based clinical practice recommendations for the comprehensive care of persons with diabetes. Recommendations are divided into four sections: (1) screening, diagnosis, glycemic targets, and glycemic monitoring; (2) comorbidities and complications, including obesity and management with lifestyle, nutrition, and bariatric surgery, hypertension, dyslipidemia, retinopathy, neuropathy, diabetic kidney disease, and cardiovascular disease; (3) management of prediabetes, type 2 diabetes with antihyperglycemic pharmacotherapy and glycemic targets, type 1 diabetes with insulin therapy, hypoglycemia, hospitalized persons, and women with diabetes in pregnancy; (4) education and new topics regarding diabetes and infertility, nutritional supplements, secondary diabetes, social determinants of health, and virtual care, as well as updated recommendations on cancer risk, nonpharmacologic components of pediatric care plans, depression, education and team approach, occupational risk, role of sleep medicine, and vaccinations in persons with diabetes.

CONCLUSIONS

This updated clinical practice guideline provides evidence-based recommendations to assist with person-centered, team-based clinical decision-making to improve the care of persons with diabetes mellitus.

The Effect of Resveratrol on Blood Lipid Profile: A Dose-Response Meta-Analysis of Randomized Controlled Trials

(1) Background: The effects of resveratrol on blood lipids are controversial. Whether there is a dose-response of the lipid profile upon resveratrol supplementation is unknown. (2) Methods: This dose-response meta-analysis of randomized controlled trials (RCTs) was performed to explore the effects of resveratrol supplementation on lipid profile. A systematical and comprehensive search of several databases was conducted by 30 June 2022. (3) Results: The results indicated that the intake of resveratrol could significantly decrease the total cholesterol (TC) (mean difference = −10.28; 95%CI: −13.79, −6.76, p < 0.001), triglyceride (TG) (Mean difference = −856; 95%CI: −12.37, −4.75, p < 0.001) and low-density lipoprotein cholesterol (LDL-C) (mean difference = −5.69; 95%CI: −11.07, −0.31, p = 0.038) level, but did not alter the level of high-density lipoprotein cholesterol (HDL-C). In the non-linear dose−response analysis, we observed a significant effect of the supplementation dosage on the level of LDL-C (p-nonlinearity = 0.002). Results from the sub-group analysis showed that the reduction of LDL-C was more significant in the trials with a duration of ≥12 weeks and in subjects with type 2 diabetes mellitus. (4) Conclusion: Findings from this study suggest that resveratrol may be beneficial to reduce TC, TG, and LDL-C levels in the blood. The dosage of the resveratrol intervention is an essential factor that affects the level of LDL-C.

Effects of the Treatment with Flavonoids on Metabolic Syndrome Components in Humans: A Systematic Review Focusing on Mechanisms of Action

Diets high in bioactive compounds, such as polyphenols, have been used to mitigate metabolic syndrome (MetS). Polyphenols are a large group of naturally occurring bioactive compounds, classified into two main classes: non-flavonoids and flavonoids. Flavonoids are distributed in foods, such as fruits, vegetables, tea, red wine, and cocoa. Studies have already demonstrated the benefits of flavonoids on the cardiovascular and nervous systems, as well as cancer cells. The present review summarizes the results of clinical studies that evaluated the effects of flavonoids on the components of the MetS and associated complications when offered as supplements over the long term. The results show that flavonoids can significantly modulate several metabolic parameters, such as lipid profile, blood pressure, and blood glucose. Only theaflavin and catechin were unable to affect metabolic parameters. Moreover, only body weight and body mass index were unaltered. Thus, the evidence presented in this systematic review offers bases in support of a flavonoid supplementation, held for at least 3 weeks, as a strategy to improve several metabolic parameters and, consequently, reduce the risk of diseases associated with MetS. This fact becomes stronger due to the rare side effects reported with flavonoids.

Neuroprotective Effects of Resveratrol by Modifying Cholesterol Metabolism and Aβ Processing in SAMP8 Mice

Cholesterol metabolism seems dysregulated and linked to amyloid-β (Aβ) formation in neurodegeneration, but the underlying mechanisms are poorly known. Resveratrol (RSV) is a polyphenol with antioxidant activity and neuroprotective properties. Here, we analyzed the effect of age and RSV supplementation on cholesterol metabolism in the brain and blood serum, and its potential link to Aβ processing, in SAMP8 mice—an animal model of aging and Alzheimer’s disease. In the brain, our results revealed an age-related increase in ApoE and unesterified cholesterol in the plasma membrane whereas LDL receptor, HMG-CoA reductase, HMG-CoA-C1 synthase, and ABCA1 transporter remained unaltered. Furthermore, BACE-1 and APP gene expression was decreased. This dysregulation could be involved in the amyloidogenic processing pathway of APP towards Aβ formation. In turn, RSV exhibited an age-dependent effect. While levels of unesterified cholesterol in the plasma membrane were not affected by RSV, several participants in cholesterol uptake, release, and de novo synthesis differed, depending on age. Thus, RSV supplementation exhibited a different neuroprotective effect acting on Aβ processing or cholesterol metabolism in the brain at earlier or later ages, respectively. In blood serum, HDL lipoprotein and free cholesterol were increased by age, whereas VLDL and LDL lipoproteins remained unaltered. Again, the protective effect of RSV by decreasing the LDL or increasing the HDL levels also seems to depend on the intervention’s moment. In conclusion, age is a prominent factor for cholesterol metabolism dysregulation in the brain of SAMP8 mice and influences the protective effects of RSV through cholesterol metabolism and Aβ processing.

Effect of Resveratrol Content in Red Wine on Circulating Sex Hormone-Binding Globulin: Lessons from a Pilot Clinical Trial

SCOPE

Low sex hormone-binding globulin (SHBG) levels are associated with higher risk of developing cardiovascular disease. Epidemiological studies have shown that red wine has beneficial effects on cardiovascular disease. In this work if resveratrol content in red wine increases SHBG levels is explored.

METHODS AND RESULTS

A pilot study aims at testing the effect of drinking for 14 days two types of red wine with different resveratrol content is conducted in 26 healthy volunteers. SHBG levels and several biochemical parameters are measured at the beginning and the end of every period. Results show that consumption of both wines does not change body mass index or biochemical markers of liver injury. The low resveratrol wine does not modify the lipid profile or SHBG levels. By contrast, red wine with high resveratrol content significantly reduces total cholesterol in both men and women. Finally, red wine with high resveratrol content increases circulating SHBG in women but not in men.

CONCLUSIONS

Red wine rich in resveratrol reduces total cholesterol in men and women and increases SHBG only in women. Further research aims at investigating the potential SHBG role enhancement mediated by resveratrol regarding cardiovascular protection that presents women in comparison with men seems warranted.

Effect of resveratrol supplementation on hepatic steatosis and cardiovascular indices in overweight subjects with type 2 diabetes: a double-blind, randomized controlled trial

BACKGROUND

Patients with type 2 diabetes mellitus (T2DM) are prone to develop non-alcoholic fatty liver disease (NAFLD) and cardiovascular diseases (CVD). We aimed to investigate whether the resveratrol supplementation improves novel hepatic and cardiovascular indices in these patients.

METHODS

We conducted a double-blind, randomized controlled trial for 8 weeks. Seventy-six patients with T2DM were randomly assigned to receive 1000 mg/day resveratrol or placebo. Levels of lipid accumulation product (LAP), visceral adiposity index (VAI), Castelli risk index I (CRI-I), CRI-II and atherogenic coefficient (AC) were measured at the beginning and after intervention.

RESULTS

A total of 71 participants completed the trial. After adjusting for confounding factors including medications, diabetes duration, energy intake and physical activity, no significant difference was found between the intervention group and the control group in LAP (mean change: - 2.46 ± 23.3 vs. 1.43 ± 14.3; P = 0.43), VAI (mean change: - 0.25 ± 1.1 vs. - 0.02 ± 0.6; P = 0.47), CRI-I (mean change: - 0.25 ± 0.9 vs. - 0.09 ± 0.5; P = 0.79), CRI-II (mean change: - 0.23 ± 0.7 vs. - 0.06 ± 0.6; P = 0.38) and AC (mean change: - 0.25 ± 0.9 vs. - 0.09 ± 0.5; P = 0.79).

CONCLUSIONS

Resveratrol supplementation had no effect on hepatic steatosis and cardiovascular indices. Further clinical trials, especially among subjects with dyslipidemia are needed to reach a firm conclusion. In addition, taking all medications should be controlled in future studies. Trial registration The protocol was registered on 29/12/2017 at the Iranian clinical trials website (IRCT20171118037528N1) with URL: https://en.irct.ir/trial/27734 .

Resveratrol: Potential Application in Sepsis

Sepsis is a life-threatening organ dysfunction syndrome caused by host response disorders due to infection or infectious factors and is a common complication of patients with clinical trauma, burns, and infection. Resveratrol is a natural polyphenol compound that is a SIRT-1 activator with anti-inflammatory, antiviral, antibacterial, antifungal inhibitory abilities as well as cardiovascular and anti-tumor protective effects. In recent years, some scholars have applied resveratrol in animal models of sepsis and found that it has an organ protective effect and can improve the survival time and reduce the mortality of animals with sepsis. In this study, Medline (Pubmed), embase, and other databases were searched to retrieve literature published in 2021 using the keywords “resveratrol” and “sepsis,” and then the potential of resveratrol for the treatment of sepsis was reviewed and prospected to provide some basis for future clinical research.

Effects of garlic extract on lipid profile in patients with coronary artery disease: A systematic review and meta-analysis of randomised clinical trials

This meta-analysis was conducted to evaluate the effects of garlic extract on total cholesterol (TC), triglycerides (TG), low-density lipoprotein-cholesterol (LDL-c) and high-density lipoprotein-cholesterol (HDL-c), among the patients with coronary artery disease (CAD). Literature searches were conducted in EMBASE, Scopus, PubMed, Web of Science and Cochrane Library until Sep18th, 2020. Inter-study heterogeneity was examined using Cochrane's Q and I² tests. The random-effect models were utilised to pool the weighted mean differences (WMDs) and the corresponding 95% confidence intervals (CIs). Six articles were enrolled in the current meta-analysis. Garlic consumption significantly reduced TC levels (WMD -16.32 mg/dL; 95% CI -31.22, -1.43; P = .032). We found no significant effects on TG (WMD -10.93 mg/dL; 95% CI -26.19, 4.32; P = .160), HDL-c (WMD 4.55 mg/dL; 95% CI -1.13, 10.23; P = .116) and LDL-c concentrations (WMD -3.65 mg/dL; 95% CI -13.21, 5.92; P = .455). Significant heterogeneity was observed for HDL-c (I²  = 76.8%). However, the findings of sensitivity analysis revealed that upon exclusion of the potential heterogeneity source, the pooled WMD on HDL-c levels were stable. Garlic supplementation may result in a decrease in TC, but will not affect TG, HDL-c and LDL-c levels among CAD patients.

The effects of resveratrol supplementation in patients with type 2 diabetes, metabolic syndrome, and nonalcoholic fatty liver disease: an umbrella review of meta-analyses of randomized controlled trials

BACKGROUND

Uncertainty remains about the estimates of the effects for resveratrol supplementation, including the certainty of the evidence for each estimate and the magnitude of the observed impact based on the minimal important difference.

OBJECTIVE

We aimed to provide an overview of the effects of resveratrol supplementation, in comparison to control groups, for the management of cardiometabolic risk factors in patients with type 2 diabetes (T2D), metabolic syndrome (MetS), and nonalcoholic fatty liver disease (NAFLD).

METHODS

PubMed, Scopus, and ISI Web of Science were searched from inception to May 2021. For each meta-analysis, the mean difference and its 95% CI were recalculated using a random-effects model. The certainty of evidence was rated using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach.

RESULTS

We identified 11 meta-analyses corresponding to 29 outcomes in 1476 individuals with T2D, 17 meta-analyses reporting 26 outcomes in 727 participants with the MetS, and 10 meta-analyses reporting 24 outcomes in 271 patients with NAFLD. Resveratrol supplementation had beneficial effects on some outcomes such as blood pressure, lipid profile, glycemic control, and insulin resistance in T2D, waist circumference in MetS, and body-weight and inflammation markers in NAFLD; however, for almost all outcomes, the magnitude of the effect was trivial, the certainty of evidence was very low to low, or the number of trials was too few. In the case of glycated hemoglobin (HbA1c), there was evidence that resveratrol can exert favorable and clinically important effects in the short term (<12 wk; mean difference: -1.05%, 95% CI: -2.09%, -0.02%; n = 6; GRADE = moderate).

CONCLUSIONS

Current evidence does not support supplementation with resveratrol for the management of cardiometabolic risk factors in patients with T2D, MetS, and NAFLD. In the case of HbA1c, subject to the limitations such as short-term follow-up and small sample size, there was a clinically important effect. The protocol of the present systematic review was registered in Open Science Framework (https://osf.io/ake85; registration doi: 10.17605/OSF.IO/AKE85).

Resveratrol on the Metabolic Reprogramming in Liver: Implications for Advanced Atherosclerosis

Background/Aims: Atherosclerosis (AS) is one of the major leading causes of death globally, which is highly correlated with metabolic abnormalities. Resveratrol (REV) exerts beneficial effects on atherosclerosis. Our aim is to clarify the involvement of liver metabolic reprogramming and the atheroprotective effects of REV.

Methods: ApoE-deficient mice were administered with normal diet (N), high-fat diet (H), or HFD with REV (HR). Twenty-four weeks after treatment, Oil Red O staining was used to assess the severity of AS. Non-targeted metabolomics was employed to obtain metabolic signatures of the liver from different groups.

Results: High-fat diet–induced AS was alleviated by REV, with less lipid accumulation in the lesions. The metabolic profiles of liver tissues from N, H, and HR groups were analyzed. A total of 1,146 and 765 differentially expressed features were identified between N and H groups, and H and HR groups, respectively. KEGG enrichment analysis uncovered several metabolism-related pathways, which are potential pathogenesis mechanisms and therapeutic targets including “primary bile acid biosynthesis,” “phenylalanine metabolism,” and “glycerophospholipid metabolism.” We further conducted trend analysis using 555 metabolites with one-way ANOVA, where p < 0.05 and PLS-DA VIP >1. We found that REV could reverse the detrimental effect of high-fat diet–induced atherosclerosis. These metabolites were enriched in pathways including “biosynthesis of unsaturated fatty acids” and “intestinal immune network for IgA production.” The metabolites involved in these pathways could be the potential biomarkers for AS-related liver metabolic reprogramming and the mechanism of REV treatment.

Conclusions: REV exerted atheroprotective effects partially by modulating the liver metabolism.

Caloric Restriction Mimetics in Nutrition and Clinical Trials

The human diet and dietary patterns are closely linked to the health status. High-calorie Western-style diets have increasingly come under scrutiny as their caloric load and composition contribute to the development of non-communicable diseases, such as diabetes, cancer, obesity, and cardiovascular disorders. On the other hand, calorie-reduced and health-promoting diets have shown promising results in maintaining health and reducing disease burden throughout aging. More recently, pharmacological Caloric Restriction Mimetics (CRMs) have gained interest of the public and scientific community as promising candidates that mimic some of the myriad of effects induced by caloric restriction. Importantly, many of the CRM candidates activate autophagy, prolong life- and healthspan in model organisms and ameliorate diverse disease symptoms without the need to cut calories. Among others, glycolytic inhibitors (e.g., D-allulose, D-glucosamine), hydroxycitric acid, NAD+ precursors, polyamines (e.g., spermidine), polyphenols (e.g., resveratrol, dimethoxychalcones, curcumin, EGCG, quercetin) and salicylic acid qualify as CRM candidates, which are naturally available via foods and beverages. However, it is yet unclear how these bioactive substances contribute to the benefits of healthy diets. In this review, we thus discuss dietary sources, availability and intake levels of dietary CRMs. Finally, since translational research on CRMs has entered the clinical stage, we provide a summary of their effects in clinical trials.

Towards resolving the enigma of the dichotomy of resveratrol: cis- and trans-resveratrol have opposite effects on TyrRS-regulated PARP1 activation

Unlike widely perceived, resveratrol (RSV) decreased the average lifespan and extended only the replicative lifespan in yeast. Similarly, although not widely discussed, RSV is also known to evoke neurite degeneration, kidney toxicity, atherosclerosis, premature senescence, and genotoxicity through yet unknown mechanisms. Nevertheless, in vivo animal models of diseases and human clinical trials demonstrate inconsistent protective and beneficial effects. Therefore, the mechanism of action of RSV that elicits beneficial effects remains an enigma. In a previously published work, we demonstrated structural similarities between RSV and tyrosine amino acid. RSV acts as a tyrosine antagonist and competes with it to bind to human tyrosyl-tRNA synthetase (TyrRS). Interestingly, although both isomers of RSV bind to TyrRS, only the cis-isomer evokes a unique structural change at the active site to promote its interaction with poly-ADP-ribose polymerase 1 (PARP1), a major determinant of cellular NAD+-dependent stress response. However, retention of trans-RSV in the active site of TyrRS mimics its tyrosine-bound conformation that inhibits the auto-poly-ADP-ribos(PAR)ylation of PARP1. Therefore, we proposed that cis-RSV-induced TyrRS-regulated auto-PARylation of PARP1 would contribute, at least in part, to the reported health benefits of RSV through the induction of protective stress response. This observation suggested that trans-RSV would inhibit TyrRS/PARP1-mediated protective stress response and would instead elicit an opposite effect compared to cis-RSV. Interestingly, most recent studies also confirmed the conversion of trans-RSV and its metabolites to cis-RSV in the physiological context. Therefore, the finding that cis-RSV and trans-RSV induce two distinct conformations of TyrRS with opposite effects on the auto-PARylation of PARP1 provides a potential molecular basis for the observed dichotomic effects of RSV under different experimental paradigms. However, the fact that natural RSV exists as a diastereomeric mixture of its cis and trans isomers and cis-RSV is also a physiologically relevant isoform has not yet gained much scientific attention.

The Role of Resveratrol in Liver Disease: A Comprehensive Review from In Vitro to Clinical Trials

Many studies have shown that resveratrol has a lot of therapeutic effects on liver disorders. Its administration can significantly increase the survival rate after liver transplantation, reduce fat deposition and ischemia-induced necrosis and apoptosis in Wistar rats. Resveratrol can provide Liver protection against chemical, cholestatic, and alcohol-mediated damage. It can improve glucose metabolism and lipid profile, reduce liver fibrosis, and steatosis. Additionally, it is capable of altering the fatty acid composition of the liver cells. Resveratrol may be a potential treatment option for the management of non-alcoholic fatty liver disease (NAFLD) due to its anti-inflammatory, antioxidant, and calorie-restricting effects. There are also studies that have evaluated the effect of resveratrol on lipid and liver enzyme profiles among patients with metabolic syndrome (MetS) and related disorders. Based on the extent of liver disease worldwide and the need to find new treatment possibilities, this review critically examines current in vitro and in vivo preclinical studies and human clinical studies related to liver protection.

Natural Bioactive Compounds Useful in Clinical Management of Metabolic Syndrome

Metabolic syndrome (MetS) is a clinical manifestation characterized by a plethora of comorbidities, including hyperglycemia, abdominal obesity, arterial hypertension, and dyslipidemia. All MetS comorbidities participate to induce a low-grade inflammation state and oxidative stress, typical of this syndrome. MetS is related to an increased risk of cardiovascular diseases and early death, with an important impact on health-care costs. For its clinic management a poly-pharmaceutical therapy is often required, but this can cause side effects and reduce the patient's compliance. For this reason, finding a valid and alternative therapeutic strategy, natural and free of side effects, could represent a useful tool in the fight the MetS. In this context, the use of functional foods, and the assumption of natural bioactive compounds (NBCs), could exert beneficial effects on body weight, blood pressure and glucose metabolism control, on endothelial damage, on the improvement of lipid profile, on the inflammatory state, and on oxidative stress. This review focuses on the possible beneficial role of NBCs in the prevention and in the clinical management of MetS and its comorbidities.

Resveratrol confers neuroprotection against high-fat diet in a mouse model of Alzheimer's disease via modulation of proteolytic mechanisms

Cumulative evidence indicates that excessive consumption of calories from saturated fat contributes to the development of Alzheimer's disease (AD). Here, we assess the triggering and progression of AD pathology induced by a high-fat diet (HFD), and the effects of resveratrol, a polyphenol found in common dietary sources with pleiotropic neuroprotective activities. Over 16 weeks, male wild type (WT) and AD transgenic 5XFAD mice were fed a control diet, HFD (60% kcal from fat), or HFD supplemented with 0.1% resveratrol. Resveratrol protected against HFD-induced memory loss in WT mice and prevented memory loss in 5XFAD mice. Resveratrol also reduced the amyloid burden aggravated by HFD in 5XFAD, and protected against HFD-induced tau pathology in both WT and 5XFAD strains. At the mechanistic level, resveratrol inhibited the HFD-increased amyloidogenic processing of the amyloid precursor protein in both strains; it also restored abnormal high levels in the proteolytic activity of the ubiquitin-proteasome system induced by HFD, suggesting the presence of a compensatory mechanism to counteract the accumulation of aberrant proteins. Thus, our data suggest that resveratrol can correct the harmful effects of HFD in the brain and may be a potential therapeutic agent against obesity-related disorders and AD pathology.

The Potential of Resveratrol to Act as a Caloric Restriction Mimetic Appears to Be Limited: Insights from Studies in Mice

Caloric restriction (CR) has been shown repeatedly to prolong the lifespan in laboratory animals, with its benefits dependent on molecular targets forming part of the nutrient signaling network, including the NAD-dependent deacetylase silent mating type information regulation 2 homologue 1 (SIRT1). It has been hypothesized that the stilbene resveratrol (RSV) may counteract age- and obesity-related diseases similarly to CR. In yeast and worms, RSV-promoted longevity also depended on SIRT1. While it remains unclear whether RSV can prolong lifespans in mammals, some studies in rodents supplemented with RSV have reported lowered body weight (BW) and fat mass, improved insulin sensitivity, lowered cholesterol levels, increased fitness, and mitochondrial biogenesis. Molecular mechanisms possibly leading to such changes include altered gene transcription and activation of SIRT1, AMP-activated kinase (AMPK), and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A). However, some mouse models did not benefit from RSV treatment to the same extent as others. We conducted a literature search on PubMed (15 April, 2020) for trials directly comparing RSV application to CR feeding in mice. In most studies retrieved by this systematic PubMed search, mice supplemented with RSV did not show significant reductions of BW, glucose, or insulin. Moreover, in some of these studies, RSV and CR treatments affected molecular targets differently and/or findings on RSV and CR impacts varied between trials. We discuss those RSV-induced changes in gene transcription hypothesized to partly counteract age-related alterations. Although there may be a moderate effect of RSV supplementation on parameters such as insulin sensitivity toward a more CR-like profile in mice, data are inconsistent. Likewise, RSV supplementation trials in humans report controversial findings. While we consider that RSV may, under certain circumstances, moderately mimic some aspects of CR, current evidence does not fully support its use to prevent or treat age- or obesity-related diseases.

Resveratrol diminishes bisphenol A-induced oxidative stress through TRPM2 channel in the mouse kidney cortical collecting duct cells

Bisphenol A (BisPH-A) is a latent danger that threatens our health, which we frequently exposure in our modern life (e.g. the widespread use of drinking water in plastic pet bottles). But the BisPH-A induced transient receptor potential melastatin 2 (TRPM2)-mediated oxidative stress and apoptosis in these cells has not been studied yet. Calcium (Ca²⁺) plays an important role in a versatile intracellular signal transduction that works over a wide range to regulate oxidative stress processes. TRPM2 is activated by oxidative stress and it has emerged as an important Ca²⁺ signaling mechanism in a variety of cells, contributing many cellular functions including cell death. Resveratrol (RESV), which belongs to the polyphenol group, acts as an antioxidant, eliminating cellular oxidative stress and increasing the body's resistance to diseases. The current study aimed to elucidate the effect of antioxidant resveratrol on TRPM2-mediated oxidative stress induced by BisPH-A exposure in the mouse kidney cortical collecting duct cells (mpkCCD_cl4). The cells were divided into four groups as control, resveratrol (50 µM for 24 h), BisPH-A (100 µM for 24 h) and BisPH-A + RESV. Intracellular free Ca²⁺ concentrations and TRPM2 channel currents were high in BisPH-A treated cells, but decreased with resveratrol treatment. In addition, BisPH-A induced mitochondrial membrane depolarization, reactive oxygen species (ROS), caspase 3, caspase 9 and apoptosis values were decreased by the resveratrol treatment. In conclusion, resveratrol protected cells from BisPH-A induced oxidative damage. In this study, we showed that TRPM2 channel mediates this protective effect of resveratrol.

The Effects of Polyphenol Supplementation in Addition to Calorie Restricted Diets and/or Physical Activity on Body Composition Parameters: A Systematic Review of Randomized Trials

Background: Both, calorie restricted diets (CRD) and physical activity (PA) are conventional obesity therapies but their effectiveness is usually limited in the long-term. Polyphenols are bioactive compounds that have shown to possess some anti-obesity properties. The synergic effects between dietary polyphenols and CRD or PA on body weight and fat are supported by several animal studies, but evidence in human is still inconsistent. Thus, our aim was to review the combined effects of polyphenol supplementation with CRD and/or PA on body weight and fat, body mass index (BMI) and waist circumference (WC) in overweight or obese adults. Methods: Electronic databases (PubMed, Web of Science and Cochrane CENTRAL) were searched for randomized clinical trials (RCT) examining the combination of polyphenols with CRD and/or PA (up to December 31st, 2019). Articles were included if they had a duration of intervention ≥ 4 weeks. Both, quality and risk of bias of the included studies were assessed using the Cochrane RoB2 Tool. Results: The review included 4 and 11 RCTs investigating the anti-obesity effects of polyphenol supplementation combined with CRD and PA, respectively. Isoflavone supplementation may increase fat loss during exercise among post-menopausal women in non-Asian studies. In the rest of RCTs regarding polyphenol supplementation and CRD or PA, no additive changes were found. Conclusion: The results do not yet support polyphenol supplementation as a complementary strategy for enhancing the effectiveness of CRD and PA on weight and fat loss. However, this review suggests that isoflavone and soy products combined with lifestyle changes, especially exercise, provide additional anti-obesity effects in postmenopausal women. The potential role of polyphenols alone or, especially, in addition to conventional therapies (CRD and PA) mostly remains uncertain; and therefore, larger and longer RCTs examining these effects are needed. Protocol Registration: PROSPERO CRD42020159890.

Resveratrol Regulates the Expression of Genes Involved in CoQ Synthesis in Liver in Mice Fed with High Fat Diet

Resveratrol (RSV) is a bioactive natural molecule that induces antioxidant activity and increases protection against oxidative damage. RSV could be used to mitigate damages associated to metabolic diseases and aging. Particularly, RSV regulates different aspects of mitochondrial metabolism. However, no information is available about the effects of RSV on Coenzyme Q (CoQ), a central component in the mitochondrial electron transport chain. Here, we report for the first time that RSV modulates COQ genes and parameters associated to metabolic syndrome in mice. Mice fed with high fat diet (HFD) presented a higher weight gain, triglycerides (TGs) and cholesterol levels while RSV reverted TGs to control level but not weight or cholesterol. HFD induced a decrease of COQs gene mRNA level, whereas RSV reversed this decrease in most of the COQs genes. However, RSV did not show effect on CoQ₉, CoQ₁₀ and total CoQ levels, neither in CoQ-dependent antioxidant enzymes. HFD influenced mitochondrial dynamics and mitophagy markers. RSV modulated the levels of PINK1 and PARKIN and their ratio, indicating modulation of mitophagy. In summary, we report that RSV influences some of the metabolic adaptations of HFD affecting mitochondrial physiology while also regulates COQs gene expression levels in a process that can be associated with mitochondrial dynamics and turnover.