Antioxidant Intervention to Improve Cognition in the Aging Brain: The Example of Hydroxytyrosol and Resveratrol

Resveratrol evokes neuroprotective effects and improves foot stance following kainate-induced excitotoxic damage to the mouse spinal cord

Excitotoxicity, characterized by over-activation of glutamate receptors, is a major contributor to spinal cord injury (SCI) pathophysiology, resulting in neuronal death and loss of locomotor function. In our previous in vitro studies, we showed that excitotoxicity induced by the glutamate analogue kainate (KA) leads to a significant reduction in the number of neurons, providing a model for SCI. Our current objective was to assess the neuroprotective role of resveratrol (RESV), a natural polyphenol, following KA-induced SCI. In vivo excitotoxicity was induced by intraspinal injection of KA immediately followed by RESV administration to Balb/C adult male mice. In neonatal mouse spinal cord preparations, excitotoxicity was transiently induced by bath-applied KA, either with or without RESV. KA administration resulted in a significant deterioration in hindlimb motor coordination and balance during locomotion, which was partially reverted by RESV. Additionally, RESV preserved neurons in both dorsal and ventral regions. Sirtuin 2 (SIRT2) immunoreactive signal was increased by RESV, while the selective SIRT1 inhibitor 6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide (EX-527) attenuated RESV neuroprotective effects. These findings suggest that RESV attenuation of excitotoxic-induced neuronal loss and locomotor deficits is mediated, at least in part, through the activation of SIRT1, potentially involving SIRT2 as well. Indeed, our results highlight the potential use of RESV to enhance neuroprotective strategies for SCI.

Investigating nutrient biomarkers of healthy brain aging: a multimodal brain imaging study

The emerging field of Nutritional Cognitive Neuroscience aims to uncover specific foods and nutrients that promote healthy brain aging. Central to this effort is the discovery of nutrient profiles that can be targeted in nutritional interventions designed to promote brain health with respect to multimodal neuroimaging measures of brain structure, function, and metabolism. The present study therefore conducted one of the largest and most comprehensive nutrient biomarker studies examining multimodal neuroimaging measures of brain health within a sample of 100 older adults. To assess brain health, a comprehensive battery of well-established cognitive and brain imaging measures was administered, along with 13 blood-based biomarkers of diet and nutrition. The findings of this study revealed distinct patterns of aging, categorized into two phenotypes of brain health based on hierarchical clustering. One phenotype demonstrated an accelerated rate of aging, while the other exhibited slower-than-expected aging. A t-test analysis of dietary biomarkers that distinguished these phenotypes revealed a nutrient profile with higher concentrations of specific fatty acids, antioxidants, and vitamins. Study participants with this nutrient profile demonstrated better cognitive scores and delayed brain aging, as determined by a t-test of the means. Notably, participant characteristics such as demographics, fitness levels, and anthropometrics did not account for the observed differences in brain aging. Therefore, the nutrient pattern identified by the present study motivates the design of neuroscience-guided dietary interventions to promote healthy brain aging.

Cellular ROS and Antioxidants: Physiological and Pathological Role

Reactive oxygen species (ROS) are highly reactive oxygen derivatives that include free radicals such as superoxide anion radical (O2•-) and hydroxyl radical (HO•), as well as non-radical molecules hydrogen peroxide (H2O2), peroxynitrite (ONOO-), and hypochlorous acid (HOCl) [...].

Exploring the multimodal health-promoting properties of resveratrol: A comprehensive review

Resveratrol, a natural polyphenol in various plants, has gained significant attention for its potential health-promoting properties. It has been demonstrated, after reviewing various clinical and in vitro studies, that resveratrol possesses potent antioxidant potential. Resveratrol demonstrates cellular component protection by directly neutralizing free radicals (FRs) and enhancing the expression of natural antioxidant enzymes, thereby mitigating oxidative damage to proteins, lipids, and nucleic acids. Clinical trials have shown promising results, indicating that resveratrol supplementation can enhance antioxidant defenses and reduce oxidative damage markers in various populations. In addition to its antioxidant effects, resveratrol exhibits potent anti-inflammatory properties. It can modulate key inflammatory pathways, such as nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs), thereby suppressing the production of pro-inflammatory cytokines and chemokines. Furthermore, resveratrol's multimodal effects extend beyond its antioxidant and anti-inflammatory properties. It has been discovered to exert regulatory effects on various cellular processes, including apoptosis, cell cycle progression, angiogenesis, and immunological responses. The primary aim of this review paper is to provide a thorough overview of the current knowledge on resveratrol, including its chemical composition, bioaccessibility, clinical effectiveness, and utilization in nanotechnology to enhance its bioavailability. From future perspectives, revising the administration methods for certain contexts and understanding the underlying systems responsible for resveratrol's effects will require further inquiry. For the highest potential health results, advanced trial-based research is necessary for combinational nano-delivery of resveratrol.

Pharmacokinetics of Hydroxytyrosol and Its Sulfate and Glucuronide Metabolites after the Oral Administration of Table Olives to Sprague-Dawley Rats

The pharmacokinetics (PK) of hydroxytyrosol and its metabolites were characterized following oral administration to Sprague-Dawley rats of 3.85 and 7.70 g of destoned Arbequina table olives/kg. Plasma samples were analyzed using a fully validated method consisting of liquid extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Noncompartmental PK analysis of hydroxytyrosol demonstrated linear PK between doses of 2.95 and 5.85 mg hydroxytyrosol/kg. Half-life was approximately 2.5 h, while mean residence time was around 4 h. Clearance occurred by conversion to two sulfate and two glucuronide conjugates. The area under the plasma concentration-time curve (AUC) ratios of metabolites versus parent hydroxytyrosol was approximately 7-9-fold for the sulfate and below 0.25 for the glucuronide, indicating sulfation as the predominant metabolic pathway. Despite extensive metabolism, hydroxytyrosol remained in plasma for up to 8 h with AUCs of 4293 and 8919 min·nmol/L for the doses of 3.85 and 7.70 g/kg, respectively. Therefore, table olives provide a more sustained plasma profile than other foods containing hydroxytyrosol, which may enhance its health-protecting activities.

[Effect of resveratrol on cognitive functions in older adults: a systematic review and meta-analysis]

Introduction

Introduction: resveratrol has multiple beneficial effects on different body systems, including the central nervous system, however, the results reported on the effect on cognitive functions in older adults are inconsistent. Therefore, the purpose of this systematic review is to present a synthesis of knowledge about the effect of resveratrol on cognitive functions in older adults. Method: a systematic review was carried out according to the PRISMA-2009 criteria. The search for articles was carried out until September 7, 2021 in PubMed, Scopus, Web of Science, PsycINFO, SciELO, and TESIUNAM. The outcome variables were delayed, immediate, and working memory, and processing speed. The standardized mean difference (SMD) was estimated to assess the effect. Results: one thousand sixty-five studies were found, of which six met the eligibility criteria for the systematic review and meta-analysis. No significant effect was found on delayed memory (SMD = 0.69, 95 % CI: 0.85-2.23, p = 0.38), immediate memory (SMD = 0.56, 95 % CI: -0.20-1.31, p = 0.15), working memory (SMD = -0.21, 95 % CI: -0.74-0.32, p = 0.43) and processing speed (SMD = 0.25, 95 % CI: -0.58-1.07, p = 0.55). Conclusion: our results suggest that resveratrol does not have an effect on cognitive functions in older adults, however, it is necessary to carry out more studies with different doses, type of nutraceutical formulation and treatment time.

Survival and longevity of European rulers: geographical influences and exploring potential factors, including the Mediterranean diet - a historical analysis from 1354 to the twentieth century

Significant regional variability in lifespan in Europe is influenced by environmental factors and lifestyle behaviors, including diet. This study investigates the impact of geographical region on the lifespan of European rulers spanning from the fourteenth century to the present day. By analyzing historical records and literature, we aim to identify region-specific dietary patterns and lifestyle factors that may have contributed to longer lifespans among rulers. The hypothesis to be tested is that rulers from Southern European countries, where the traditional Mediterranean diet is consumed by the local people, may exhibit longer lifespans compared to rulers from other regions, due to the well-documented health benefits associated with this dietary pattern. We extracted comprehensive information for each ruler, encompassing their sex, birth and death dates, age, age of enthronement, duration of rulership, country, and cause of death (natural vs. non-natural). To determine their nationality, we coded rulers based on their hypothetical present-day residence (2023). Utilizing the EuroVoc Geographical classification, we categorized the countries into four regions: Northern, Western, Southern, Central and Eastern Europe. While Cox regression models did not find significant differences in survival rates among regions, further analysis stratified by time periods revealed intriguing trends. Contrary to our initial predictions, the Northern region displayed better survival rates compared to the Southern region between 1354 and 1499, whereas survival rates were similar across regions from 1500 to 1749. However, after 1750, all regions, except the Southern region, exhibited significantly improved survival rates, suggesting advancements in healthcare and lifestyle factors. These findings underscore the dynamic influence of both region and time period on health and longevity. Interestingly, despite the prevalence of the Mediterranean diet in the Southern region of Europe, rulers from this region did not demonstrate longer lifespans compared to their counterparts in other regions. This suggests that additional lifestyle factors may have played a more prominent role in their longevity. In conclusion, our study sheds light on the intricate relationship between region, time period, and lifespan among European rulers. Although the Mediterranean diet is often associated with health benefits, our findings indicate that it alone may not account for differences in ruler longevity across regions. Further research is warranted to explore the impact of other lifestyle factors on the health and lifespan of European rulers throughout history.

Bilirubin and Redox Stress in Age-Related Brain Diseases

Cellular redox status has a crucial role in brain physiology, as well as in pathologic conditions. Physiologic senescence, by dysregulating cellular redox homeostasis and decreasing antioxidant defenses, enhances the central nervous system's susceptibility to diseases. The reduction of free radical accumulation through lifestyle changes, and the supplementation of antioxidants as a prophylactic and therapeutic approach to increase brain health, are strongly suggested. Bilirubin is a powerful endogenous antioxidant, with more and more recognized roles as a biomarker of disease resistance, a predictor of all-cause mortality, and a molecule that may promote health in adults. The alteration of the expression and activity of the enzymes involved in bilirubin production, as well as an altered blood bilirubin level, are often reported in neurologic conditions and neurodegenerative diseases (together denoted NCDs) in aging. These changes may predict or contribute both positively and negatively to the diseases. Understanding the role of bilirubin in the onset and progression of NCDs will be functional to consider the benefits vs. the drawbacks and to hypothesize the best strategies for its manipulation for therapeutic purposes.

Effects of Desert Olive Tree Pearls Containing High Hydroxytyrosol Concentrations on the Cognitive Functions of Middle-Aged and Older Adults

The Japanese population has the world's longest life expectancy but faces the challenge of extending the healthy life expectancy without developing chronic diseases. Therefore, the effectiveness of products derived from olives used in the Mediterranean diet as a potential dietary solution has attracted attention. This study examined the effects of desert olive tree pearls (DOTPs), which contain 162 times more polyphenol hydroxytyrosol than olive oil, on the cognitive function of middle-aged and older adults using the Cognitrax test. Participants (aged 51-82 years) were assigned to the DOTP intake (n = 36) or placebo group (n = 36) in a randomized, double-blind, placebo-controlled, parallel-group study. The participants received 3 g of DOTPs or placebo in olive oil twice daily for 12 weeks. Among cognitive domains, complex attention had a significant time × group interaction effect (p = 0.049) between the DOTP and placebo groups. The simple main effect for this item was significantly different (p < 0.001 and p = 0.572, respectively). Time effects were significant (p < 0.05) for the psychomotor speed, reaction time, cognitive flexibility, processing speed, and executive function domains. Therefore, DOTPs have the potential to alleviate cognitive problems faced by middle-aged and older adults in Japan.

Hydroxytyrosol Interference with Inflammaging via Modulation of Inflammation and Autophagy

Inflammaging refers to a chronic, systemic, low-grade inflammation, driven by immune (mainly macrophages) and non-immune cells stimulated by endogenous/self, misplaced or altered molecules, belonging to physiological aging. This age-related inflammatory status is characterized by increased inflammation and decreased macroautophagy/autophagy (a degradation process that removes unnecessary or dysfunctional cell components). Inflammaging predisposes to age-related diseases, including obesity, type-2 diabetes, cancer, cardiovascular and neurodegenerative disorders, as well as vulnerability to infectious diseases and vaccine failure, representing thus a major target for anti-aging strategies. Phenolic compounds-found in extra-virgin olive oil (EVOO)-are well known for their beneficial effect on longevity. Among them, hydroxytyrosol (HTyr) appears to greatly contribute to healthy aging by its documented potent antioxidant activity. In addition, HTyr can modulate inflammation and autophagy, thus possibly counteracting and reducing inflammaging. In this review, we reference the literature on pure HTyr as a modulatory agent of inflammation and autophagy, in order to highlight its possible interference with inflammaging. This HTyr-mediated activity might contribute to healthy aging and delay the development or progression of diseases related to aging.

Mitochondrial Complex I, a Possible Sensible Site of cAMP Pathway in Aging

In mammals during aging, reactive oxygen species (ROS), produced by the mitochondrial respiratory chain, cause oxidative damage of macromolecules leading to respiratory chain dysfunction, which in turn increases ROS mitochondrial production. Many efforts have been made to understand the role of oxidative stress in aging and age-related diseases. The complex I of the mitochondrial respiratory chain is the major source of ROS production and its dysfunctions have been associated with several forms of neurodegeneration, other common human diseases and aging. Complex I-ROS production and complex I content have been proposed as the major determinants for longevity. The cAMP signal has a role in the regulation of complex I activity and the decrease of ROS production. In the last years, an increasing number of studies have attempted to activate cAMP signaling to treat age-related diseases associated with mitochondrial dysfunctions and ROS production. This idea comes from a long-line of studies showing a main role of cAMP signal in the memory consolidation mechanism and in the regulation of mitochondrial functions. Here, we discuss several evidences on the possible connection between complex I and cAMP pathway in the aging process.