Clinical Evaluation of Effects of Chronic Resveratrol Supplementation on Cerebrovascular Function, Cognition, Mood, Physical Function and General Well-Being in Postmenopausal Women-Rationale and Study Design

Targeting Neurological Disorders with Stilbenes: Bridging the Preclinical-Clinical Gap

Neurological disorders (NDs) encompass a range of debilitating conditions that affect the nervous system, including prevalent illnesses such as Alzheimer's disease, Parkinson's disease, and ischemic stroke. Despite significant ongoing studies, effective therapeutic strategies to halt or slow down the progression of these illnesses are still lacking. Stilbenes, a class of natural polyphenols, have shown potential as candidates for therapeutic strategies due to their capacity to protect the nervous system. Preclinical studies have provided strong evidence that stilbenes can regulate many cellular pathways implicated in neurodegeneration, with resveratrol being a well-studied compound that has shown the ability to reduce oxidative damage, promote neurogenesis, and enhance mitochondrial function - crucial for maintaining brain health. In preclinical animal models, initial research has also shown promise in additional substances such as piceatannol and pterostilbene. Furthermore, clinical studies have explored the therapeutic benefits of stilbenes in NDs. Despite promising results in preclinical research, the use of stilbenes in clinical trials is currently limited, with most studies focusing on resveratrol. Although several clinical studies have demonstrated the beneficial impact of resveratrol supplementation on brain health and degenerative consequences, other investigations have yielded ambiguous findings, underscoring the urgent need for more comprehensive and precisely planned clinical research. This study delves into the potential benefits of stilbenes as neuroprotective agents for NDs. It emphasizes the need for more clinical research to enhance our understanding of their therapeutic effectiveness in specific patient groups.

Latest advances and clinical application prospects of resveratrol therapy for neurocognitive disorders

Neurocognitive disorders, such as Alzheimer's disease, vascular dementia, and postoperative cognitive dysfunction, are non-psychiatric brain syndromes in which a significant decline in cognitive function causes great trauma to the mental status of the patient. The lack of effective treatments for neurocognitive disorders imposes a considerable burden on society, including a substantial economic impact. Over the past few decades, the identification of resveratrol, a natural plant compound, has provided researchers with an opportunity to formulate novel strategies for the treatment of neurocognitive disorders. This is because resveratrol effectively protects the brain of those with neurocognitive disorders by targeting some mechanisms such as inflammation and oxidative stress. This article reviews the status of recent research investigating the use of resveratrol for the treatment of different neurocognitive disorders. By examining the possible mechanisms of action of resveratrol and the shared mechanisms of different neurocognitive disorders, treatments for neurocognitive disorders may be further clarified.

Mechanistic insights into the potential role of dietary polyphenols and their nanoformulation in the management of Alzheimer's disease

Alzheimer's disease (AD) is a very common neurodegenerative disorder associated with memory loss and a progressive decline in cognitive activity. The two major pathophysiological factors responsible for AD are amyloid plaques (comprising amyloid-beta aggregates) and neurofibrillary tangles (consisting of hyperphosphorylated tau protein). Polyphenols, a class of naturally occurring compounds, are immensely beneficial for the treatment or management of various disorders and illnesses. Naturally occurring sources of polyphenols include plants and plant-based foods, such as fruits, herbs, tea, vegetables, coffee, red wine, and dark chocolate. Polyphenols have unique properties, such as being the major source of anti-oxidants and possessing anti-aging and anti-cancerous properties. Currently, dietary polyphenols have become a potential therapeutic approach for the management of AD, depending on various research findings. Dietary polyphenols can be an effective strategy to tackle multifactorial events that occur with AD. For instance, naturally occurring polyphenols have been reported to exhibit neuroprotection by modulating the Aβ biogenesis pathway in AD. Many nanoformulations have been established to enhance the bioavailability of polyphenols, with nanonization being the most promising. This review comprehensively provides mechanistic insights into the neuroprotective potential of dietary polyphenols in treating AD. It also reviews the usability of dietary polyphenol as nanoformulation for AD treatment.

TrkB phosphorylation in serum extracellular vesicles correlates with cognitive function enhanced by ergothioneine in humans

Oral administration of the food-derived antioxidant amino acid ergothioneine (ERGO) results in its efficient distribution in the brain and enhances cognitive function. However, effect of ERGO deficiency on cognitive impairment and the underlying mechanisms remain unknown. We revealed that cognitive function and hippocampal neurogenesis were lower in mice fed an ERGO-free diet than in those fed the control diet. Furthermore, ERGO supplementation to achieve the control diet ERGO levels reversed these effects and restored ERGO concentrations in the plasma and hippocampus. The ERGO-induced recovery of cognitive function and hippocampal neurogenesis was blocked by inhibiting the neurotrophic factor receptor tropomyosin receptor kinase B (TrkB), with a concomitant reduction in hippocampal phosphorylated TrkB, suggesting the involvement of TrkB in these events in mice. Phosphorylated TrkB was also detected in extracellular vesicles (EVs) derived from serum of volunteers who had been orally administered placebo or ERGO-containing tablets. Importantly, the ratio of serum EV-derived phosphorylated TrkB was significantly higher in the ERGO-treated group than in the placebo-treated group and was positively correlated with both serum ERGO concentrations and several cognitive domain scores from Cognitrax. Altogether, TrkB phosphorylation is involved in ERGO-induced cognitive enhancement in mice, and TrkB phosphorylation levels in serum EVs may quantitatively represent ERGO-induced cognitive enhancement in humans.

The Journey of Resveratrol from Vineyards to Clinics

With rising technological advancements, several factors influence the lifestyle of people and stimulate chronic inflammation that severely affects the human body. Chronic inflammation leads to a broad range of physical and pathophysiological distress. For many years, non-steroidal drugs and corticosteroids were most frequently used in treating inflammation and related ailments. However, long-term usage of these drugs aggravates the conditions of chronic diseases and is presented with morbid side effects, especially in old age. Hence, the quest for safe and less toxic anti-inflammatory compounds of high therapeutic potential with least adverse side effects has shifted researchers' attention to ancient medicinal system. Resveratrol (RSV) - 3,4,5^' trihydroxystilbene is one such naturally available polyphenolic stilbene derivative obtained from various plant sources. For over 2000 years, these plants have been used in Asian medicinal system for curing inflammation-associated disorders. There is a wealth of in vitro, in vivo and clinical evidence that shows RSV could induce anti-aging health benefits including, anti-cancer, anti-inflammatory, anti-oxidant, phytoesterogenic, and cardio protective properties. However, the issue of rapid elimination of RSV through the metabolic system and its low bio-availability is of paramount importance which is being studied extensively. Therefore, in this article, we scientifically reviewed the molecular targets, biological activities, beneficial and contradicting effects of RSV as evinced by clinical studies for the prevention and treatment of inflammation-mediated chronic disorders.

Randomised controlled trials for the prevention of cognitive decline or dementia: A systematic review

Dementia prevention research has progressed rapidly in recent years, with publication of several large lifestyle intervention trials, and renewed interest in pharmacological interventions, notably for individuals with Alzheimer's disease biomarkers, warranting an updated review of results and methodology. We identified 112 completed trials testing the efficacy of single-domain pharmacological (n = 33, 29%), nutritional (n = 27, 24%), physical activity (n = 18, 16%) and cognitive stimulation (n = 13, 12%), or multidomain (n = 22, 20%) interventions on incident dementia, or a relevant intermediate marker (e.g. cognitive function, biomarkers or dementia risk scores) in people without dementia. The earliest trials tested pharmacological interventions or nutritional supplements, but lifestyle interventions predominated in the last decade. In total, 21 (19%) trials demonstrated a clear beneficial effect on the pre-specified primary outcome (or all co-primary outcomes), but only two (10%) were large-scale (testing blood pressure lowering (Syst-Eur) or multidomain (FINGER) interventions on incident dementia and cognitive change in cognitive function, respectively). Of the 116 ongoing trials, 40% (n = 46) are testing multidomain interventions. Recent methodological shifts concern target populations, primary outcome measures, and intervention design, but study design remains constant (parallel group randomised controlled trial). Future trials may consider using adaptive trials or interventions, and more targeted approaches, since certain interventions may be more effective in certain subgroups of the population, and at specific times in the life-course. Efforts should also be made to increase the representativeness and diversity of prevention trial populations.

Polyphenols effect on cerebrovascular health

Polyphenols are a wide group of plant components that include a high number of individual compounds and are present in foods, dietary supplements and drugs. Many of them have shown pharmacological effects, are used in cardiovascular disease prevention, and not as many have been assayed in cancer treatment or co-treatment. In the last few years, however, the research on polyphenols implications in a healthy aging and especially in neurodegeneration and cognition improvement has increased dramatically. Most of the results found in this sense are again related with the capacity of some specific polyphenols to regulate the blood flow, but this time at the cerebral level, and to protect the endothelium at this same level. In this thorough review, we want to concentrate precisely on the effect of polyphenols on the cerebrovascular homeostasis, reviewing the mechanisms that underline this effect and the radiological methods and endogenous biomarkers that are used in human trials aimed at showing the beneficial effect of polyphenols or polyphenols rich foods on neuroprotection and cognition function.

Nutrition, Physical Activity, and Other Lifestyle Factors in the Prevention of Cognitive Decline and Dementia

Multiple factors combined are currently recognized as contributors to cognitive decline. The main independent risk factor for cognitive impairment and dementia is advanced age followed by other determinants such as genetic, socioeconomic, and environmental factors, including nutrition and physical activity. In the next decades, a rise in dementia cases is expected due largely to the aging of the world population. There are no hitherto effective pharmaceutical therapies to treat age-associated cognitive impairment and dementia, which underscores the crucial role of prevention. A relationship among diet, physical activity, and other lifestyle factors with cognitive function has been intensively studied with mounting evidence supporting the role of these determinants in the development of cognitive decline and dementia, which is a chief cause of disability globally. Several dietary patterns, foods, and nutrients have been investigated in this regard, with some encouraging and other disappointing results. This review presents the current evidence for the effects of dietary patterns, dietary components, some supplements, physical activity, sleep patterns, and social engagement on the prevention or delay of the onset of age-related cognitive decline and dementia.

Cerebrovascular Function in Hormonal Migraine: An Exploratory Study

Background: Migraineurs, particularly young premenopausal women, are at increased risk of cerebrovascular disease; however, there is currently limited evidence as to whether hormonal migraine is associated with poor cerebrovascular function.

Objectives: The objectives of this study were to: (1) investigate the potential association of cerebrovascular function with hormonal migraine and (2) determine whether abnormalities of cerebrovascular function in hormonal migraineurs are associated with migraine-related disability and/or quality of life.

Method: A cross-sectional study was undertaken in 50 hormonal migraineurs (mean age: 38.7 ± 1.2 years) and 29 controls (mean age: 35.6 ± 1.8 years). Data were collected at a single point in time from all participants during the inter-ictal period when they were free from migraine and not menstruating. Transcranial Doppler ultrasound was used to measure resting blood flow velocity and cerebrovascular responsiveness (CVR) to hypercapnia and cognitive stimulation (neurovascular coupling) in the left and right middle cerebral artery (MCA). Additionally, hormonal migraineurs completed three questionnaires to assess migraine-related disability and quality of life as well as migraine frequency and intensity: Headache Impact Test-6™, Migraine-Specific Quality of Life and Migraine Disability Assessment.

Results: Hormonal migraineurs had lower resting mean blood flow velocity (MBFV) (P = 0.009) and neurovascular coupling during cognitive stimulation (P = 0.010) in the left MCA than controls. No such differences were found in the right MCA. Additionally, heart rate (P = 0.004) was higher in hormonal migraineurs than controls. However, no differences in CVR to hypercapnia were found between hormonal migraineurs and controls. Multi-variate analysis revealed age to be a significant (P = 0.012) predictor of MBFV in the left MCA. Negative correlations between headache frequency and CVR to hypercapnia in the left (P = 0.026) and right MCA (P = 0.044) were found. Additionally, negative correlations between neurovascular coupling during the 2-Back 1.5 s task in the right MCA and the MSQoL emotional (P = 0.013) and role-function restrictive (P = 0.039) domains were found.

Conclusions: This is the first study to show that hormonal migraineurs have poorer cerebrovascular function, as represented by lower resting MBFV and impaired neurovascular coupling in the left MCA. Future studies should investigate whether improving cerebrovascular function can prevent hormonal migraine and improve quality of life.

Clinical Trial Registration: ACTRN12618001230246.

Long-term administration of resveratrol at low doses improves neurocognitive performance as well as cerebral blood flow and modulates the inflammatory pathways in the brain

There is an increasing prevalence of coincident cerebrovascular deficiency and cognitive dysfunction with aging. Increased oxidative stress as well as inflammation that occurs with aging are associated with the impairment of cerebral vascularization. Interestingly, Resveratrol (RSV), a natural phytoalexin, is known to be a strong antioxidant and possesses anti-inflammatory properties. Collectively, these observations strongly suggest that RSV could protect against cerebral vascularization defect and then improves the decline cognitive function associated with aging. In order to test this hypothesis, we investigated the effect of a long-term RSV treatment (1.25 mg/day for 5 months) on cognitive performances of animals that we have allowed to age normally. Then, we further analyzed the gene expression profile and the cerebral blood flow in the brain. By means of novel object recognition (NOR) test, we observed that RSV enhanced NOR performances of aged rats. In addition, RSV enhanced cerebral blood flow during NOR task in aged rats. Using microarrays experiments, we also showed that several pathways related to inflammation and oxidative stress (Eicosanoid signaling, MIF-mediated innate immunity, NF-kB signaling, TNFR2 signaling, IL6 signaling, Production of nitric oxide and ROS) were down-regulated in the brain of RSV treatments rats compared to control rats. In conclusion, these results support that a long-term treatment with RSV improves cognitive performance in the elderly male rat model. This effect is associated with an increase in cerebral blood flow and a decrease in the expression of several pro-inflammatory pathways in the brain.

Effect of Polyphenols on Cognitive Function: Evidence from Population-Based Studies and Clinical Trials

Due to progressive population aging, a new dementia case occurs at every 3 seconds, placing a heavy burden of disease. Identifying potential risk or preventive factors is emphasized owing to a lack of effective treatment for dementia. There has been emerging evidence on the link of certain dietary components, particularly polyphenols, to brain wellness and cognitive outcomes. Findings from animal and in vitro studies appear more consistent and conclusive. However, such an association has not been investigated in depth in human beings. In this review, we examined studies on the effect of dietary polyphenols (including flavonoids, curcumin, and resveratrol) on cognitive function. Intervention in early stages of dementia/Alzheimer's disease might be a target to slow down age-related cognitive decline before disease onset. We summarized 28 epidemiological studies (8 cross-sectional and 20 cohort studies) and 55 trials in this review. Preliminary evidence from epidemiological data provides the necessity for intervention trials, even though the measures of polyphenol intake tend to be less precise. Clinical trials are in favor of the role of some polyphenols in benefiting specific domains of cognition. This review also describes the divergence of results and current limitations of research in this field.

Resveratrol: A "miracle" drug in neuropsychiatry or a cognitive enhancer for mice only? A systematic review and meta-analysis

BACKGROUND

Over the last decade resveratrol has been trialled for the prevention and treatment of cognitive decline; however, the results have shown a conflict between human studies compared with animal studies, especially on cognition, blood pressure, neuroimaging, and mood.

METHODS

Human clinical trials and animal studies published prior to January 2020, were identified searching across major electronic databases. PRISMA guidelines were used for data extraction, which was independently performed by two authors. Pooled standard mean difference (SMD, random effect model) and odds ratios (ORs) were calculated.

RESULTS

Most publications on animal models reported positive outcomes on cognition and brain function following exposure to resveratrol or grape seed extracts. By contrast, 11 meta-analyses of data from human placebo vs resveratrol, grape or wine treatment trials identified no statistically significant effect on a variety of measures, including cognitive and mood assessments, grey matter volume and blood pressure.

CONCLUSIONS

Based on currently available data, the promising effects of resveratrol in animal models is not replicated in human clinical trials. The effects, if any, of resveratrol on human cognition are likely to be small. This work may be useful for the design and implementation of future pre-clinical and clinical studies using resveratrol in a neurological setting.

Evaluation of Cognitive Performance following Fish-Oil and Curcumin Supplementation in Middle-Aged and Older Adults with Overweight or Obesity

BACKGROUND

Obesity accelerates age-related cognitive decline, which is partly mediated by vascular dysfunction.

OBJECTIVE

The aim was to test the hypothesis that supplementation with fish oil and curcumin can enhance cognitive performance by improving cerebral circulatory function in overweight or obese middle-aged to older adults.

METHODS

In a 16-wk double-blind, placebo-controlled intervention trial, adults [50-80 y; BMI (kg/m2): 25-40] were randomly assigned to either fish oil (2000 mg/d DHA + 400 mg/d EPA), curcumin (160 mg/d), or a combination. Effects on cerebrovascular function (primary outcome) and cardiovascular risk factors were reported previously. Effects on cognitive performance and cerebrovascular responsiveness (CVR) to cognitive stimuli are reported herein. One-factor ANOVA with post hoc analyses was conducted between groups in the whole cohort and in males and females separately. Two-factor ANOVA was conducted to assess independent effects of fish oil and curcumin and a potential interaction. Correlations between outcomes (those obtained herein and previously reported) were also examined.

RESULTS

Compared with placebo, fish oil improved CVR to a processing speed test (4.4% ± 1.9% vs. -2.2% ± 2.1%; P = 0.023) and processing speed in males only (Z-score: 0.6 ± 0.2 vs. 0.1 ± 0.2; P = 0.043). Changes in processing speed correlated inversely with changes in blood pressure (R = -0.243, P = 0.006) and C-reactive protein (R = -0.183, P = 0.046). Curcumin improved CVR in a working memory test (3.6% ± 1.2% vs. -0.2% ± 0.2%, P = 0.026) and, in males only, performance of a verbal memory test compared with placebo (Z-score: 0.2 ± 0.1 vs. -0.5 ± 0.2, P = 0.039). Combining fish oil with curcumin did not produce additional benefits.

CONCLUSIONS

Improvements in processing speed following fish-oil supplementation in middle-aged to older males might be mediated by improvements in circulatory function. Mechanisms underlying the cognitive benefit seen with curcumin are unknown. As cognitive benefits were found in males only, further evaluation of sex differences in responsiveness to supplementation is warranted. This trial was registered at the Australian and New Zealand Clinical Trial Register at https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=370788 as ACTRN12616000732482p.

Grapes and their derivatives in modulation of cognitive decline: a critical review of epidemiological and randomized-controlled trials in humans

With an increase in life expectancy, the incidence of chronic degenerative pathologies such as dementia has progressively risen. Cognitive impairment leads to the gradual loss of skills, which results in substantial personal and financial cost at the individual and societal levels. Grapes and wines are rich in healthy compounds, which may help to maintain homeostasis and reduce the risk of several chronic illnesses, including dementia. This review analyzed papers that were systematically searched in PubMed, MEDLINE, Embase, and CAB-Abstract, using the association between grapes (or their derivatives) and their effects on cognitive functions in humans. Analysis was restricted to epidemiological and randomized-controlled studies. Consumption of grape juice (200-500 mL/day) and/or light-to-moderate wine (one to four glasses/day) was generally associated with improved cognitive performance, while the results for other alcoholic beverages were controversial and inconclusive. Bioactive molecules contained in grapes and wine were also considered, with particular attention paid to resveratrol. Due to the relatively high doses required (150-1000 mg/day) for bioactivity coupled with its low bioavailability, resveratrol is only one of the possible grape-derived compounds that may partly underpin the beneficial effects of grapes on the central nervous system.

Sexual hormones regulate the redox status and mitochondrial function in the brain. Pathological implications

Compared to other organs, the brain is especially exposed to oxidative stress. In general, brains from young females tend to present lower oxidative damage in comparison to their male counterparts. This has been attributed to higher antioxidant defenses and a better mitochondrial function in females, which has been linked to neuroprotection in this group. However, these differences usually disappear with aging, and the incidence of brain pathologies increases in aged females. Sexual hormones, which suffer a decrease with normal aging, have been proposed as the key factors involved in these gender differences. Here, we provide an overview of redox status and mitochondrial function regulation by sexual hormones and their influence in normal brain aging. Furthermore, we discuss how sexual hormones, as well as phytoestrogens, may play an important role in the development and progression of several brain pathologies, including neurodegenerative diseases such as Alzheimer's and Parkinson's diseases, stroke or brain cancer.

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Sex hormones are reduced with aging, especially in females, affecting redox balance.

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Normal aging is associated to a worse redox homeostasis in the brain.

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Young females show better mitochondrial function and higher antioxidant defenses.

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Development of brain pathologies is influenced by sex hormones and phytoestrogens.

Impact of Red Wine Consumption on Cardiovascular Health

BACKGROUND

The devastating effects of heavy alcohol drinking have been long time recognized. In the last decades, potential benefits of modest red wine drinking were suggested. In European countries in which red wide intake is not negligible (such as France), the association between cholesterol and cardiovascular (CV) risk was less evident, suggesting the action of some protective molecules in red wine or other foods and drinks.

METHODS

This narrative review is based on the material searched for and obtained via PubMed up to May 2016. The search terms we used were: "red wine, cardiovascular, alcohol" in combination with "polyphenols, heart failure, infarction".

RESULTS

Epidemiological and mechanistic evidence of a J-shaped relationship between red wine intake and CV risk further supported the "French paradox". Specific components of red wine both in vitro and in animal models were discovered. Polyphenols and especially resveratrol largely contribute to CV prevention mainly through antioxidant properties. They exert beneficial effects on endothelial dysfunction and hypertension, dyslipidemia, metabolic diseases, thus reducing the risk of adverse CV events such as myocardial infarction ischemic stroke and heart failure. Of interest, recent studies pointed out the role of ethanol itself as a potential cardioprotective agent, but a clear epidemiological evidence is still missing. The aim of this narrative review is to update current knowledge on the intracellular mechanism underlying the cardioprotective effects of polyphenols and ethanol. Furthermore, we summarized the results of epidemiological studies, emphasizing their methodological criticisms and the need for randomized clinical trials able to clarify the potential role of red wine consumption in reducing CV risk.

CONCLUSION

Caution in avowing underestimation of the global burden of alcohol-related diseases was particularly used.

Aging, lifestyle and dementia

Aging is the greatest risk factor for most diseases including cancer, cardiovascular disorders, and neurodegenerative disease. There is emerging evidence that interventions that improve metabolic health with aging may also be effective for brain health. The most robust interventions are non-pharmacological and include limiting calorie or protein intake, increasing aerobic exercise, or environmental enrichment. In humans, dietary patterns including the Mediterranean, Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) and Okinawan diets are associated with improved age-related health and may reduce neurodegenerative disease including dementia. Rapamycin, metformin and resveratrol act on nutrient sensing pathways that improve cardiometabolic health and decrease the risk for age-associated disease. There is some evidence that they may reduce the risk for dementia in rodents. There is a growing recognition that improving metabolic function may be an effective way to optimize brain health during aging.

Health benefits of resveratrol: Evidence from clinical studies

Resveratrol is a polyphenolic nutraceutical that exhibits pleiotropic activities in human subjects. The efficacy, safety, and pharmacokinetics of resveratrol have been documented in over 244 clinical trials, with an additional 27 clinical trials currently ongoing. Resveretrol is reported to potentially improve the therapeutic outcome in patients suffering from diabetes mellitus, obesity, colorectal cancer, breast cancer, multiple myeloma, metabolic syndrome, hypertension, Alzheimer's disease, stroke, cardiovascular diseases, kidney diseases, inflammatory diseases, and rhinopharyngitis. The polyphenol is reported to be safe at doses up to 5 g/d, when used either alone or as a combination therapy. The molecular basis for the pleiotropic activities of resveratrol are based on its ability to modulate multiple cell signaling molecules such as cytokines, caspases, matrix metalloproteinases, Wnt, nuclear factor-κB, Notch, 5'-AMP-activated protein kinase, intercellular adhesion molecule, vascular cell adhesion molecule, sirtuin type 1, peroxisome proliferator-activated receptor-γ coactivator 1α, insulin-like growth factor 1, insulin-like growth factor-binding protein 3, Ras association domain family 1α, pAkt, vascular endothelial growth factor, cyclooxygenase 2, nuclear factor erythroid 2 like 2, and Kelch-like ECH-associated protein 1. Although the clinical utility of resveratrol is well documented, the rapid metabolism and poor bioavailability have limited its therapeutic use. In this regard, the recently produced micronized resveratrol formulation called SRT501, shows promise. This review discusses the currently available clinical data on resveratrol in the prevention, management, and treatment of various diseases and disorders. Based on the current evidence, the potential utility of this molecule in the clinic is discussed.

Resveratrol: from enhanced biosynthesis and bioavailability to multitargeting chronic diseases

Resveratrol, a phytoalexin with a wide range of pharmacological properties is synthesised by plants in response to stress, injury, infection or UV radiations. As it is a secondary metabolite with many health promoting properties, various methods employing microorganisms and genetic manipulation of different synthetic enzymes, have been comprehensively studied to increase its production. Its rapid metabolism and low bioavailability have been addressed by the use of bio enhancers and nano-formulations. This flavonoid is extensively researched due to its pharmacological properties such as anti-oxidative, anti-inflammatory and immuno-modulating effects. Knowledge of these properties of resveratrol has led to elaborate studies on its effect on diabetes, neurodegenerative diseases, cancer, ageing, obesity and cardiovascular diseases. At molecular level it targets sirtuin, adenosine monophosphate kinase, nuclear Factor-κB, inflammatory cytokines, anti-oxidant enzymes along with cellular processes such as angiogenesis, apoptosis, mitochondrial biogenesis, gluconeogenesis and lipid metabolism. This review discusses the properties of resveratrol and the different approaches of addressing the unfavourable synthesis and pharmacokinetics of this stilbene. Pre-clinical evaluations of resveratrol on diabetes mellitus, cardiovascular and neurological diseases are elaborately discussed and the underlying pathways involved in its therapeutic activity have been given paramount importance. Following the pre-clinical studies, clinical trials on the same reveal the efficacy of resveratrol in the effective management of these diseases. This review provides an intricate insight on resveratrol's significance from a dietary component to a therapeutic agent.

Resveratrol and Related Stilbenoids, Nutraceutical/Dietary Complements with Health-Promoting Actions: Industrial Production, Safety, and the Search for Mode of Action

This paper reviews the potential of stilbenoids as nutraceuticals. Stilbenoid compounds in wine are considered key factors in health-promoting benefits. Resveratrol and resveratrol-related compounds are found in a large diversity of vegetal products. The stilbene composition varies from wine to wine and from one season to another. Therefore, the article also reviews how food science and technology and wine industry may help in providing wines and/or food supplements with efficacious concentrations of stilbenes. The review also presents results from clinical trials and those derived from genomic/transcriptomic studies. The most studied stilbenoid, resveratrol, is a very safe compound. On the other hand, the potential benefits of stilbene intake are multiple and are apparently due to downregulation more than upregulation of gene expression. The field may take advantage from identifying the mechanism of action(s) and from providing useful data to show evidence for specific health benefits in a given tissue or for combating a given disease.

Resveratrol provides benefits in mice with type II diabetes-induced chronic renal failure through AMPK signaling pathway

Type II diabetes-induced ischemic injuries are known to lead to the rapid degeneration of the kidneys as a result of chronic renal failure. Chronic renal failure is a condition, which typically manifests with symptoms including cardiovascular system and left ventricular hypertrophy, atherosclerosis as well as arterial and aortic stiffness. Resveratrol is a multifunctional compound that has been reported to produce beneficial outcomes for patients with type-II diabetes due to prevention of oxidative stress and apoptosis. However, the beneficial effects of resveratrol in chronic renal failure and the underlying mechanisms have remained to be fully elucidated. The present study investigated the therapeutic effects of resveratrol in mice with chronic renal failure induced by type-II diabetes and assessed the mechanism of action. Oxidative stress, apoptosis and adenosine monophosphate-activated protein kinase (AMPK) in the renal cells of the model mice were assessed. Changes in inflammatory factors renal cells from experimental mice as well as insulin resistance were also analyzed. Morphological changes and immunocytes in renal cells were determined by immunostaining. The results demonstrated that resveratrol treatment decreased the apoptotic rate of renal cells from experimental mice. Oxidative stress also improved in renal cells, as indicated by inhibition of superoxide dismutase and reduced glutathione and 4-hydroxy-2-nonenal levels. In addition, insulin resistance was improved after an 8-week treatment with resveratrol. Inflammatory factors were decreased and factors promoting kidney function were increased after resveratrol treatment. Furthermore, morphological changes were observed to be ameliorated, indicating the therapeutic efficacy of resveratrol. In addition, immunocyte precipitation in renal cells was markedly decreased in resveratrol-treated mice. Importantly, the AMPK signaling pathway was found to be involved in the beneficial effect of resveratrol on the model mice. In conclusion, the present study suggested that resveratrol may be an ideal agent for the treatment of chronic renal failure induced by type-II diabetes through regulation of the AMPK signaling pathway, which should be further investigated in clinical trials.

Resveratrol supplementation reduces pain experience by postmenopausal women

OBJECTIVE

Pain is a common complaint among postmenopausal women. It has been postulated that vascular dysfunction caused by estrogen decline at menopause plays a key role in the initiation and progression of degradative joint disease, namely age-related osteoarthritis. We evaluated whether supplementation with resveratrol, a phytoestrogen, could improve aspects of well-being such as chronic pain that is commonly experienced by postmenopausal women.

METHODS

A 14-week randomized, double-blind, placebo-controlled intervention with trans-resveratrol (75 mg, twice daily) was conducted in 80 healthy postmenopausal women. Aspects of well-being, including pain, menopausal symptoms, sleep quality, depressive symptoms, mood states, and quality of life were assessed by Short form-36 at baseline and at the end of treatment. Rating scales were averaged to provide a composite score representing overall well-being. Cerebral vasodilator responsiveness to hypercapnia was also assessed as a surrogate marker for cerebrovascular function.

RESULTS

Compared with placebo treatment, there was a significant reduction in pain and an improvement in total well-being after resveratrol supplementation. Both benefits, including measures of quality of life, correlated with improvements in cerebrovascular function.

CONCLUSIONS

Our preliminary findings indicate potential for resveratrol treatment to reduce chronic pain in age-related osteoarthritis. Resveratrol consumption may also boost perceptions of well-being in postmenopausal women. Further investigation to elucidate underlying mechanisms is warranted.

Estrogen Interactions With Lipid Rafts Related to Neuroprotection. Impact of Brain Ageing and Menopause

Estrogens (E2) exert a plethora of neuroprotective actions against aged-associated brain diseases, including Alzheimer's disease (AD). Part of these actions takes place through binding to estrogen receptors (ER) embedded in signalosomes, where numerous signaling proteins are clustered. Signalosomes are preferentially located in lipid rafts which are dynamic membrane microstructures characterized by a peculiar lipid composition enriched in gangliosides, saturated fatty acids, cholesterol, and sphingolipids. Rapid E2 interactions with ER-related signalosomes appear to trigger intracellular signaling ultimately leading to the activation of molecular mechanisms against AD. We have previously observed that the reduction of E2 blood levels occurring during menopause induced disruption of ER-signalosomes at frontal cortical brain areas. These molecular changes may reduce neuronal protection activities, as similar ER signalosome derangements were observed in AD brains. The molecular impairments may be associated with changes in the lipid composition of lipid rafts observed in neurons during menopause and AD. These evidences indicate that the changes in lipid raft structure during aging may be at the basis of alterations in the activity of ER and other neuroprotective proteins integrated in these membrane microstructures. Moreover, E2 is a homeostatic modulator of lipid rafts. Recent work has pointed to this relevant aspect of E2 activity to preserve brain integrity, through mechanisms affecting lipid uptake and local biosynthesis in the brain. Some evidences have demonstrated that estrogens and the docosahexaenoic acid (DHA) exert synergistic effects to stabilize brain lipid matrix. DHA is essential to enhance molecular fluidity at the plasma membrane, promoting functional macromolecular interactions in signaling platforms. In support of this, DHA detriment in neuronal lipid rafts has been associated with the most common age-associated neuropathologies, namely AD and Parkinson disease. Altogether, these findings indicate that E2 may participate in brain preservation through a dual membrane-related mechanism. On the one hand, E2 interacting with ER related signalosomes may protect against neurotoxic insults. On the other hand, E2 may exert lipostatic actions to preserve lipid balance in neuronal membrane microdomains. The different aspects of the emerging multifunctional role of estrogens in membrane-related signalosomes will be discussed in this review.

Resveratrol, human health and winemaking perspectives

Resveratrol, (3, 5, 4'-trihydroxystilbene) is a non-flavonoid polyphenol stilbene synthesized by plants when damaged by infectious diseases or ionizing radiation. Although present in more than seventy plant species, grapes and wine are the major dietary contributors of resveratrol, responsible for 98% of the daily intake. In 1992, Renaud and De Lorgeril first linked wine polyphenols, including resveratrol, to the potential health benefits ascribed to regular and moderate wine consumption (the so called "French Paradox"). Since then, resveratrol has received increasing scientific interest, leading to research on its biological actions, and to a large number of published papers, which have been collected and discussed in this review. The relatively low amounts of resveratrol measured in wine following moderate consumption, however, may be insufficient to mitigate biological damage, such as that due to oxidative stress. On this basis, the authors also highlight the importance of viticulture and the winemaking process to enhance resveratrol concentrations in wine in order to bolster potential health benefits.

Effect of resveratrol on cognitive and memory performance and mood: A meta-analysis of 225 patients

Resveratrol is a natural dietary phenolic compound which is extensively present in many edible fruits, including grape, berries, pomegranates, and peanuts. Reseveratrol has a broad spectrum of biological activities including anti-aging, chemopreventive, anti-carcinogenic, anti-inflammatory and antioxidant effects and thus it is effective in related diseases. Particularly, the positive effects of resveratrol in neuropsychological diseases have been proven in in-vitro and in-vivo studies. Some clinical trials have reported that resveratrol possesses preventive and therapeutic effects in cognitive disorders. Therefore, the current systematic review and meta-analysis aimed to assess the effects of resveratrol on cognition and memory performance as well as mood state. Electronic databases including Scopus, PubMed, Science Direct, and Cochrane library were searched with the keywords "Memory", "Cognitive", "Cognition" or "Mood" with "Resveratrol" until June 2017. Only clinical studies were included in this review. We have provided the most reliable evidence to date counting results obtained from 226 individuals from four randomized clinical trials evaluating the mentioned specific effects of resveratrol. The results of this meta-analysis showed that resveratrol has no significant effect on memory and cognitive performance assessed by auditory verbal learning tests. Two parameters of Profile of Mood States (POMS) including vigor and fatigue, decreased significantly by resveratrol. However, decrease in other parameters of POMS including tense/anxiety, depression, anger, and confusion by resveratrol was not significant. The key findings from this meta-analysis are that resveratrol has no significant impact on factors related to memory and cognitive performance, including learning ability, delayed recall, retention, and recognition with all effect sizes non-significant and effectively at zero. However, it has the potential to enhance mood. Further randomized, controlled trials are needed to achieve more conclusive results.

Effects of Resveratrol on Cognitive Performance, Mood and Cerebrovascular Function in Post-Menopausal Women; A 14-Week Randomised Placebo-Controlled Intervention Trial

We tested whether chronic supplementation with resveratrol (a phytoestrogen) could improve cerebrovascular function, cognition and mood in post-menopausal women. Eighty post-menopausal women aged 45–85 years were randomised to take trans-resveratrol or placebo for 14 weeks and the effects on cognitive performance, cerebral blood flow velocity and pulsatility index (a measure of arterial stiffness) in the middle cerebral artery (using transcranial Doppler ultrasound), and cerebrovascular responsiveness (CVR) to both cognitive testing and hypercapnia were assessed. Mood questionnaires were also administered. Compared to placebo, resveratrol elicited 17% increases in CVR to both hypercapnic (p = 0.010) and cognitive stimuli (p = 0.002). Significant improvements were observed in the performance of cognitive tasks in the domain of verbal memory (p = 0.041) and in overall cognitive performance (p = 0.020), which correlated with the increase in CVR (r = 0.327; p = 0.048). Mood tended to improve in multiple measures, although not significantly. These results indicate that regular consumption of a modest dose of resveratrol can enhance both cerebrovascular function and cognition in post-menopausal women, potentially reducing their heightened risk of accelerated cognitive decline and offering a promising therapeutic treatment for menopause-related cognitive decline.

Influence of equol and resveratrol supplementation on health-related quality of life in menopausal women: A randomized, placebo-controlled study

OBJECTIVE

This study was designed to evaluate the effects of equol and resveratrol supplementation on health-related quality of life (HRQoL) in otherwise healthy menopausal women with hot flashes, anxiety and depressive symptoms.

METHODS

Sixty recently menopausal women aged 50-55 years were randomized in a 12-week, placebo-controlled trial to receive 200mg of fermented soy containing 10mg of equol and 25mg of resveratrol (1 tablet/day). The primary outcome was the change in score on the Menopause Rating Scale (MRS), used to evaluate the severity of age-/menopause-related complaints. Additional outcome measures included the subject-reported score on the Hamilton Rating Scale for Depression (HAM-D) and Nottingham Health Profile (NHP), which was used specifically to assess sleep quality.

RESULTS

The symptoms assessed by the MRS improved during treatment in the active group. Comparison between placebo and treatment groups revealed statistically significant improvement in particular for dryness of vagina (-85.7%) (p<0.001), heart discomfort (-78.8%; p<0.001) and sexual problems (-73.3%; p<0.001). On the HAM-D significant improvements at week 12 were seen in work and activities (-94.1%) (p<0.001). Subjects treated with equol and resveratrol also had significant differences in the sleep domain of the NHP (p<0.001).

CONCLUSION

These findings provide evidence that 12 weeks of dietary supplementation with equol and resveratrol may improve menopause-related quality of life in healthy women.

Poor cerebrovascular function is an early marker of cognitive decline in healthy postmenopausal women

INTRODUCTION

Impairment of cerebrovascular function becomes evident after menopause. No study has yet explored relationships between deficits in cerebrovascular function, cognitive performance, and mood in postmenopausal women.

METHOD

Cerebrovascular function was assessed in 80 healthy postmenopausal women by monitoring blood flow velocity (BFV) in the middle and posterior cerebral arteries using transcranial Doppler ultrasound at rest, following a hypercapnic challenge, and during performance of a cognitive test battery; the latter assessed domains of memory and executive functions. Various measures of mood (i.e., Profile of Mood States and Center for Epidemiological Studies Depression Scale) were also assessed.

RESULTS

Cerebral artery elasticity and BFV responsiveness to cognitive tests (neurovascular coupling) correlated with cognitive performance but not with depressive symptoms or mood states. Mood deficits were related to poor cognitive performance.

CONCLUSION

These results highlight the importance of adequate cerebral perfusion for optimized cognitive function in healthy postmenopausal women. Preventative strategies to attenuate accelerated cognitive decline should also consider restoring cerebrovascular function.

Acute Resveratrol Consumption Improves Neurovascular Coupling Capacity in Adults with Type 2 Diabetes Mellitus

Background: Poor cerebral perfusion may contribute to cognitive impairment in type 2 diabetes mellitus (T2DM). We conducted a randomized controlled trial to test the hypothesis that resveratrol can enhance cerebral vasodilator function and thereby alleviate the cognitive deficits in T2DM. We have already reported that acute resveratrol consumption improved cerebrovascular responsiveness (CVR) to hypercapnia. We now report the effects of resveratrol on neurovascular coupling capacity (CVR to cognitive stimuli), cognitive performance and correlations with plasma resveratrol concentrations. Methods: Thirty-six T2DM adults aged 40–80 years were randomized to consume single doses of resveratrol (0, 75, 150 and 300 mg) at weekly intervals. Transcranial Doppler ultrasound was used to monitor changes in blood flow velocity (BFV) during a cognitive test battery. The battery consisted of dual-tasking (finger tapping with both Trail Making task and Serial Subtraction 3 task) and a computerized multi-tasking test that required attending to four tasks simultaneously. CVR to cognitive tasks was calculated as the per cent increase in BFV from pre-test basal to peak mean blood flow velocity and also as the area under the curve for BFV. Results: Compared to placebo, 75 mg resveratrol significantly improved neurovascular coupling capacity, which correlated with plasma total resveratrol levels. Enhanced performance on the multi-tasking test battery was also evident following 75 mg and 300 mg of resveratrol. Conclusion: a single 75 mg dose of resveratrol was able to improve neurovascular coupling and cognitive performance in T2DM. Evaluation of benefits of chronic resveratrol supplementation is now warranted.

Resveratrol and Cardiovascular Diseases

The increased incidence of cardiovascular diseases (CVDs) has stimulated research for substances that could improve cardiovascular health. Among them, resveratrol (RES), a polyphenolic compound notably present in grapes and red wine, has been involved in the “French paradox”. RES is known for its antioxidant and anti-inflammatory properties and for its ability to upregulate endothelial NO synthase (eNOS). RES was able to scavenge ^•OH/O₂^•− and peroxyl radicals, which can limit the lipid peroxidation processes. Moreover, in bovine aortic endothelial cells (BAEC) under glucose-induced oxidative stress, RES restored the activity of dimethylargininedimethylaminohydrolase (DDAH), an enzyme that degrades an endogenous inhibitor of eNOS named asymmetric dimethylarginine (ADMA). Thus, RES could improve ^•NO availability and decrease the endothelial dysfunction observed in diabetes. Preclinical studies have made it possible to identify molecular targets (SIRT-1, AMPK, Nrf2, NFκB…); however, there are limited human clinical trials, and difficulties in the interpretation of results arise from the use of high-dose RES supplements in research studies, whereas low RES concentrations are present in red wine. The discussions on potential beneficial effects of RES in CVDs (atherosclerosis, hypertension, stroke, myocardial infarction, heart failure) should compare the results of preclinical studies with those of clinical trials.