Green Tea Catechins Trigger Immediate-Early Genes in the Hippocampus and Prevent Cognitive Decline and Lifespan Shortening

Enhancing healthy aging with small molecules: A mitochondrial perspective

The pursuit of enhanced health during aging has prompted the exploration of various strategies focused on reducing the decline associated with the aging process. A key area of this exploration is the management of mitochondrial dysfunction, a notable characteristic of aging. This review sheds light on the crucial role that small molecules play in augmenting healthy aging, particularly through influencing mitochondrial functions. Mitochondrial oxidative damage, a significant aspect of aging, can potentially be lessened through interventions such as coenzyme Q10, alpha-lipoic acid, and a variety of antioxidants. Additionally, this review discusses approaches for enhancing mitochondrial proteostasis, emphasizing the importance of mitochondrial unfolded protein response inducers like doxycycline, and agents that affect mitophagy, such as urolithin A, spermidine, trehalose, and taurine, which are vital for sustaining protein quality control. Of equal importance are methods for modulating mitochondrial energy production, which involve nicotinamide adenine dinucleotide boosters, adenosine 5'-monophosphate-activated protein kinase activators, and compounds like metformin and mitochondria-targeted tamoxifen that enhance metabolic function. Furthermore, the review delves into emerging strategies that encourage mitochondrial biogenesis. Together, these interventions present a promising avenue for addressing age-related mitochondrial degradation, thereby setting the stage for the development of innovative treatment approaches to meet this extensive challenge.

The relationship between dietary patterns derived from inflammation and cognitive impairment in patients undergoing hemodialysis

Introduction

Dietary patterns were shown to be closely related to inflammation, which was independently associated with cognitive impairment (CI) in patients undergoing hemodialysis (HD). However, it remains unclear the influence of dietary patterns derived from inflammation on CI in this population. This study aimed to examine the association between dietary patterns derived from C-reactive protein (CRP) and interleukin-6 (IL-6) and CI in patients undergoing HD.

Methods

Dietary intake was obtained from the simplified quantitative food frequency questionnaire. Reduced rank regression (RRR) was used to extract two dietary patterns, with IL-6 and CRP as response variables. Cognitive function was examined by the Montreal Cognitive Assessment (Beijing version). Venous blood was drawn for measuring IL-6 and CRP levels. Multivariable logistic regression was used to investigate the association between dietary patterns and CI.

Results

Dietary pattern derived from IL-6 was not significantly associated with CI. The third quartile of dietary pattern, which used CRP as the response variable, significantly contributed to the increased risk of CI (AOR 8.62, 95% CI 1.47-50.67) after controlling age, sex, education level, marital status, and residential pattern (p-for-trend = 0.028). After considering hypertension and diabetes, physical activity level, anxiety and depression, smoking and drinking status, social support, energy intake, and the dietary pattern derived from IL-6 (p-for-trend = 0.026), the relationship between the dietary pattern derived from CRP and CI remained significant (AOR 14.54, 95% CI 1.40-151.13).

Conclusion

Dietary pattern associated with high CRP level, including high intake of rice, liquor, fruit, tea and coffee and low intake of dark vegetables and juice, contributed to the increased risk of CI. The association between the consumption of seafood, sweet beverages, and alcohol and CI is yet to be established. However, they may be dietary contributing factors to inflammation in patients undergoing HD.

Effects of Green Tea Polyphenol Epigallocatechin-3-Gallate on Markers of Inflammation and Fibrosis in a Rat Model of Pulmonary Silicosis

Inhalation of silica particles causes inflammatory changes leading to fibrotizing silicosis. Considering a lack of effective therapy, and a growing information on the wide actions of green tea polyphenols, particularly epigallocatechin-3-gallate (EGCG), the aim of this study was to evaluate the early effects of EGCG on markers of inflammation and lung fibrosis in silicotic rats. The silicosis model was induced by a single transoral intratracheal instillation of silica (50 mg/mL/animal), while controls received an equivalent volume of saline. The treatment with intraperitoneal EGCG (20 mg/kg, or saline in controls) was initiated the next day after silica instillation and was given twice a week. Animals were euthanized 14 or 28 days after the treatment onset, and the total and differential counts of leukocytes in the blood and bronchoalveolar lavage fluid (BALF), wet/dry lung weight ratio, and markers of inflammation, oxidative stress, and fibrosis in the lung were determined. The presence of collagen and smooth muscle mass in the walls of bronchioles and lung vessels was investigated immunohistochemically. Early treatment with EGCG showed some potential to alleviate inflammation, and a trend to decrease oxidative stress-induced changes, including apoptosis, and a prevention of fibrotic changes in the bronchioles and pulmonary vessels. However, further investigations should be undertaken to elucidate the effects of EGCG in the lung silicosis model in more detail. In addition, because of insufficient data from EGCG delivery in silicosis, the positive and eventual adverse effects of this herbal compound should be carefully studied before any preventive use or therapy with EGCG may be recommended.

Therapeutic Effects of Green Tea Polyphenol (‒)-Epigallocatechin-3-Gallate (EGCG) in Relation to Molecular Pathways Controlling Inflammation, Oxidative Stress, and Apoptosis

(‒)-Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenol in green tea. Thanks to multiple interactions with cell surface receptors, intracellular signaling pathways, and nuclear transcription factors, EGCG possesses a wide variety of anti-inflammatory, antioxidant, antifibrotic, anti-remodelation, and tissue-protective properties which may be useful in the treatment of various diseases, particularly in cancer, and neurological, cardiovascular, respiratory, and metabolic disorders. This article reviews current information on the biological effects of EGCG in the above-mentioned disorders in relation to molecular pathways controlling inflammation, oxidative stress, and cell apoptosis.

The therapeutic potential of matcha tea: A critical review on human and animal studies

Matcha is a powdered form of Japanese green tea that has been gaining global popularity recently. Matcha tea has various health benefits, including an enhancing effect on cognitive function, cardio-metabolic health, and anti-tumorogenesis. To date, randomized clinical trials (RCT) showed that matcha decreases stress, slightly enhances attention and memory, and has no effect on mood. Results regarding the effect of matcha on cognitive function are contradictory and more RCTs are warranted. The cardio-metabolic effects of matcha have only been studied in animals, but findings were more homogenous. Consuming matcha with a high-fat diet resulted in decreased weight gain velocity, food intake, improved serum glucose and lipid profile, reduced inflammatory cytokines and ameliorated oxidative stress. Evidence regarding the anti-tumor function of matcha is very limited. Findings showed that matcha can affect proliferation, viability, antioxidant response, and cell cycle regulation of breast cancer cells. Nonetheless, more studies are needed to examine this effect on different types of cancer cells, and there is also a need to verify it using animal models. Overall, the evidence regarding the effect of matcha tea on cognitive function, cardio-metabolic function, and anti-tumor role is still limited, and conclusions cannot be drawn.

The Flavonol Quercitrin Hinders GSK3 Activity and Potentiates the Wnt/β-Catenin Signaling Pathway

The Wnt/β-catenin signaling pathway dictates cell proliferation and differentiation during embryonic development and tissue homeostasis. Its deregulation is associated with many pathological conditions, including neurodegenerative disease, frequently downregulated. The lack of efficient treatment for these diseases, including Alzheimer’s disease (AD), makes Wnt signaling an attractive target for therapies. Interestingly, novel Wnt signaling activating compounds are less frequently described than inhibitors, turning the quest for novel positive modulators even more appealing. In that sense, natural compounds are an outstanding source of potential drug leads. Here, we combine different experimental models, cell-based approaches, neuronal culture assays, and rodent behavior tests with Xenopus laevis phenotypic analysis to characterize quercitrin, a natural compound, as a novel Wnt signaling potentiator. We find that quercitrin potentiates the signaling in a concentration-dependent manner and increases the occurrence of the Xenopus secondary axis phenotype mediated by Xwnt8 injection. Using a GSK3 biosensor, we describe that quercitrin impairs GSK3 activity and increases phosphorylated GSK3β S9 levels. Treatment with XAV939, an inhibitor downstream of GSK3, impairs the quercitrin-mediated effect. Next, we show that quercitrin potentiates the Wnt3a-synaptogenic effect in hippocampal neurons in culture, which is blocked by XAV939. Quercitrin treatment also rescues the hippocampal synapse loss induced by intracerebroventricular injection of amyloid-β oligomers (AβO) in mice. Finally, quercitrin rescues AβO-mediated memory impairment, which is prevented by XAV939. Thus, our study uncovers a novel function for quercitrin as a Wnt/β-catenin signaling potentiator, describes its mechanism of action, and opens new avenues for AD treatments.

The Antiaging Activities of Phytochemicals in Dark-Colored Plant Foods: Involvement of the Autophagy- and Apoptosis-Associated Pathways

In the last two decades, human life expectancy has increased by about 10 years, but this has not been accompanied by a corresponding increase in healthy lifespan. Aging is associated with a wide range of human disorders, including cancer, diabetes, and cardiovascular and neurodegenerative diseases. Delaying the aging of organs or tissues and improving the physiological functions of the elderly can reduce the risk of aging-related diseases. Autophagy and apoptosis are crucial mechanisms for cell survival and tissue homeostasis, and may also be primary aging-regulatory pathways. Recent epidemiological studies have shown that eating more colorful plant foods could increase life expectancy. Several representative phytochemicals in dark-colored plant foods such as quercetin, catechin, curcumin, anthocyanins, and lycopene have apparent antiaging potential. Nevertheless, the antiaging signaling pathways of the phytochemicals from dark-colored plant foods remain elusive. In the present review, we summarized autophagy- and apoptosis-associated targeting pathways of those phytochemicals and discussed the core targets involved in the antiaging effects. Further clinical evaluation and exploitation of phytochemicals as antiaging agents are needed to develop novel antiaging therapeutics for preventing age-related diseases and improving a healthy lifespan.

Green Tea Polyphenol (-)-Epigallocatechin-3-Gallate (EGCG): A Time for a New Player in the Treatment of Respiratory Diseases?

(-)-Epigallocatechin-3-gallate (EGCG) is a major polyphenol of green tea that possesses a wide variety of actions. EGCG acts as a strong antioxidant which effectively scavenges reactive oxygen species (ROS), inhibits pro-oxidant enzymes including NADPH oxidase, activates antioxidant systems including superoxide dismutase, catalase, or glutathione, and reduces abundant production of nitric oxide metabolites by inducible nitric oxide synthase. ECGC also exerts potent anti-inflammatory, anti-fibrotic, pro-apoptotic, anti-tumorous, and metabolic effects via modulation of a variety of intracellular signaling cascades. Based on this knowledge, the use of EGCG could be of benefit in respiratory diseases with acute or chronic inflammatory, oxidative, and fibrotizing processes in their pathogenesis. This article reviews current information on the biological effects of EGCG in those respiratory diseases or animal models in which EGCG has been administered, i.e., acute respiratory distress syndrome, respiratory infections, COVID-19, bronchial asthma, chronic obstructive pulmonary disease, lung fibrosis, silicosis, lung cancer, pulmonary hypertension, and lung embolism, and critically discusses effectiveness of EGCG administration in these respiratory disorders. For this review, articles in English language from the PubMed database were used.

Impacts of psychological stress on high dose-rate radiation acute effects in a mouse experimental model

Psychological stress affects health. Radiation workers in the medical field or astronauts living in space have possible risks of exposure to radiation, and psychological stress is considered to be easily induced in them due to activities performed in small areas or stress conditions. The impact of psychological stress on the effects of radiation was evaluated in senescence-accelerated mouse prone 10 (SAMP10) mice and ddY mice using a confrontational housing model, which makes dominant and subordinate mice in a cage live together without severe quarrel. Mice of ddY and SAMP10 have been previously demonstrated to be influenced in terms of acute and late effects, respectively, under psychological stress by this model. In SAMP10 mice, irradiation with 4 Gy induced the death of irradiated mice under psychological stress. In ddY mice, irradiation with 5 Gy X-rays alone had almost no effect on the mouse survival, but irradiation in conditions of psychological stress promoted acute death of irradiated mice. In addition, hypocellular bone marrow was also observed histopathologically in irradiated ddY mice under stress. Psychological stress may promote damage caused by radiation through modulation of radio-sensitivity in bone marrow in mice. This model would be useful for evaluation of modulation of radiation-induced various effects by psychological stress.

Coffee Polyphenol, Chlorogenic Acid, Suppresses Brain Aging and Its Effects Are Enhanced by Milk Fat Globule Membrane Components

Mice feed with coffee polyphenols (CPP, chlorogenic acid) and milk fat globule membrane (MFGM) has increased survival rates and helps retain long-term memory. In the cerebral cortex of aged mice, CPP intake decreased the expression of the proinflammatory cytokine TNF-α, and lysosomal enzyme cathepsin B. The suppression of inflammation in the brain during aging was thought to result in the suppression of the repressor element 1-silencing transcription factor (REST) and prevention of brain aging. In contrast, CPP increased the expression of REST, cAMP-responsive element binding (CREB) and transforming growth factor β1 (TGF-β1) in the young hippocampus. The increased expression of these factors may contribute to the induction of neuronal differentiation and the suppression of memory decline with aging. Taken together, these results suggest that CPP increases CREB in the young hippocampus and suppresses inflammation in the old brain, resulting in a preventive effect on brain aging. The endotoxin levels were not elevated in the serum of aged mice. Although the mechanism of action of MFGM has not yet been elucidated, the increase in survival rate with both CPP and MFGM intake suggests that adding milk to coffee may improve not only the taste, but also the function.

Comprehensive Analysis of lncRNAs, miRNAs and mRNAs in Mouse Hippocampus With Hepatic Encephalopathy

Hepatic encephalopathy (HE) often presents with varying degrees of cognitive impairment. However, the molecular mechanism of its cognitive impairment has not been fully elucidated. Whole transcriptome analysis of hippocampus between normal and HE mice was performed by using RNA sequencing. 229 lncRNAs, 49 miRNAs and 363 mRNAs were differentially expressed in HE mice. The lncRNA-miRNA-mRNA interaction networks were established, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed. Dysregulated RNAs in interaction networks were mainly involved in synaptic plasticity and the regulation of learning and memory. In NH4Cl-treated hippocampal neurons, the dendritic spine density and maturity decreased significantly, the amplitude and frequency of mIPSC increased, while the amplitude and frequency of mEPSC decreased. These manifestations can be reversed by silencing SIX3OS1. Further research on these no-coding RNAs may lead to new therapies for the treatment and management of brain dysfunction caused by HE.

Anti-aging properties of phytoconstituents and phyto-nanoemulsions and their application in managing aging-related diseases

Aging is spontaneous and inevitable process in all living beings. It is a complex natural phenomenon that manifests as a gradual decline of physiological functions and homeostasis. Aging inevitably leads to age-associated injuries, diseases, and eventually death. The research on aging-associated diseases aimed at delaying, preventing or even reversing the aging process are of great significance for healthy aging and also for scientific progress. Numerous plant-derived compounds have anti-aging effects, but their therapeutic potential is limited due to their short shelf-life and low bioavailability. As the novel delivery system, nanoemulsion can effectively improve this defect. Nanoemulsions enhance the delivery of drugs to the target site, maintain the plasma concentration for a longer period, and minimize adverse reaction and side effects. This review describes the importance of nanoemulsions for the delivery of phyto-derived compounds and highlights the importance of nanoemulsions in the treatment of aging-related diseases. It also covers the methods of preparation, fate and safety of nanoemulsions, which will provide valuable information for the development of new strategies in treatment of aging-related diseases.

Green Tea Suppresses Brain Aging

Epidemiological studies have demonstrated that the intake of green tea is effective in reducing the risk of dementia. The most important component of green tea is epigallocatechin gallate (EGCG). Both EGCG and epigallocatechin (EGC) have been suggested to cross the blood–brain barrier to reach the brain parenchyma, but EGCG has been found to be more effective than EGC in promoting neuronal differentiation. It has also been suggested that the products of EGCG decomposition by the intestinal microbiota promote the differentiation of nerve cells and that both EGCG and its degradation products act on nerve cells with a time lag. On the other hand, the free amino acids theanine and arginine contained in green tea have stress-reducing effects. While long-term stress accelerates the aging of the brain, theanine and arginine suppress the aging of the brain due to their anti-stress effect. Since this effect is counteracted by EGCG and caffeine, the ratios between these green tea components are important for the anti-stress action. In this review, we describe how green tea suppresses brain aging, through the activation of nerve cells by both EGCG and its degradation products, and the reductions in stress achieved by theanine and arginine.

Therapeutic Effects of Catechins in Less Common Neurological and Neurodegenerative Disorders

In recent years, neurological and neurodegenerative disorders research has focused on altered molecular mechanisms in search of potential pharmacological targets, e.g., imbalances in mechanisms of response to oxidative stress, inflammation, apoptosis, autophagy, proliferation, differentiation, migration, and neuronal plasticity, which occur in less common neurological and neurodegenerative pathologies (Huntington disease, multiple sclerosis, fetal alcohol spectrum disorders, and Down syndrome). Here, we assess the effects of different catechins (particularly of epigalocatechin-3-gallate, EGCG) on these disorders, as well as their use in attenuating age-related cognitive decline in healthy individuals. Antioxidant and free radical scavenging properties of EGCG -due to their phenolic hydroxyl groups-, as well as its immunomodulatory, neuritogenic, and autophagic characteristics, makes this catechin a promising tool against neuroinflammation and microglia activation, common in these pathologies. Although EGCG promotes the inhibition of protein aggregation in experimental Huntington disease studies and improves the clinical severity in multiple sclerosis in animal models, its efficacy in humans remains controversial. EGCG may normalize DYRK1A (involved in neural plasticity) overproduction in Down syndrome, improving behavioral and neural phenotypes. In neurological pathologies caused by environmental agents, such as FASD, EGCG enhances antioxidant defense and regulates placental angiogenesis and neurodevelopmental processes. As demonstrated in animal models, catechins attenuate age-related cognitive decline, which results in improvements in long-term outcomes and working memory, reduction of hippocampal neuroinflammation, and enhancement of neuronal plasticity; however, further studies are needed. Catechins are valuable compounds for treating and preventing certain neurodegenerative and neurological diseases of genetic and environmental origin. However, the use of different doses of green tea extracts and EGCG makes it difficult to reach consistent conclusions for different populations.

Theaflavin-regulated Imd condensates control Drosophila intestinal homeostasis and aging

Black tea is the most widely consumed tea drink in the world and has consistently been reported to possess anti-aging benefits. However, whether theaflavins, one type of the characteristic phytochemicals in black tea extracts, are involved in regulating aging and lifespan in consumers remains largely unknown. In this study, we show that theaflavins play a beneficial role in preventing age-onset intestinal leakage and dysbiosis, thus delaying aging in Drosophila. Mechanistically, theaflavins regulate the condensate assembly of Imd to negatively govern the overactivation of Imd signals in fruit fly intestines. In addition, theaflavins prevent DSS-induced colitis in mice, suggesting theaflavins play a role in modulating intestinal integrity. Overall, our study reveals a molecular mechanism by which theaflavins regulate gut homeostasis likely through controlling Imd coalescence.

Matcha consumption maintains attentional function following a mild acute psychological stress without affecting a feeling of fatigue: A randomized placebo-controlled study in young adults

Tea is a beverage commonly consumed worldwide. Matcha is a type of green tea produced by drying and grinding tea leaves (Camellia sinensis L.) into a fine powder. Matcha contains catechin, theanine, and caffeine, which affect cognitive function. Epidemiological studies conducted in Japan have shown that green tea consumption improves cognitive impairment. Previously, we found that daily matcha intake improves attention and executive function in middle-aged and older people. However, its effect on cognitive function in younger adults remains unclear. Moreover, it is unclear which cognitive functions are impaired by stress. This study aimed to clarify whether the administration of matcha improves the attentional function of young adults after mild acute stress and which cognitive function is improved. We included 42 participants aged 25 to 34 years who consumed 2 g of matcha daily for 2 weeks. The Uchida-Kraepelin test was used to induce mild acute psychological stress. Memory, attention, facial expression recognition, working memory, visual information, and motor function were evaluated. Reaction times on the Stroop test for attentional function were significantly lower in the matcha group than in the placebo group. Correct hits in the emotion perception test increased significantly for participants in the matcha group compared to those in the placebo group. We found no significant between-group differences in the other tests. In conclusion, after 2 weeks of matcha intake, the attentional function was maintained after mild acute psychological stress. Thus, matcha might improve cognitive function during or after stress conditions in young adults.