Protective effects of epigallocatechin-3 gallate on atrial electrical and structural remodeling in a rabbit rapid atrial pacing model

Unraveling tea and coffee consumption effects on cardiovascular diseases risk factors: A narrative review

Backgrounds and Aims

Daily lifestyle plays a vital role in modifying the risk for cardiovascular diseases (CVDs). Our daily life isn't inseparable from nutrition intake. As such, tea and coffee are often regarded as the most consumed beverages worldwide. There have been a lot of debates on the adverse effects and benefits of consuming these popular beverages. This comprehensive review explores the different types of tea and coffee and their mechanism of action. It delves deeper into their roles in reducing CVD risk, aiding CVD recovery, lowering CVD mortality, and their varying effects across populations and regions.

Methods

An extensive literature search was conducted on PubMed. Relevant articles were identified through cross-referencing and manual searches. Excluded from the study were commentaries, case reports, clinical vignettes, and non-English articles.

Results

Tea and coffee contain varying levels of caffeine and other bioactive compounds with cardioprotective effects against oxidative stress, inflammation, and more. Genetic factors further modulate their effects. Tea flavonoids benefit cholesterol, blood pressure, and endothelial function, while coffee constituents impact oxidative stress, metabolism, insulin sensitivity, and gut flora. Moderate consumption of both beverages may offer cardiovascular benefits, but outcomes vary depending on populations and conditions. Tea and coffee consumption may influence CVD recovery by reducing mortality and improving survival, however, it must be noted that it has the potential to be harmful to some individuals.

Conclusion

Evidence suggests that moderate consumption of these beverages may be linked to reduced cardiovascular mortality, although individual characteristics and pre-existing conditions can influence outcomes. Excessive caffeine consumption, found in both beverages, may pose risks such as arrhythmias, hypertension, and cardiovascular mortality in CVD patients, with a dose-dependent nature. Future research should delve into mechanisms, genetic factors, and diverse cultural impacts of its use. Health care providers should consider individual characteristics when advising on tea and coffee consumption in the context of cardiovascular health.

Low-dose green tea intake reduces incidence of atrial fibrillation in a Chinese population

The aim of the present study was to assessthe association between green tea intake and incidence of atrial fibrillation (AF) in a Chinese population. A total of 801 (mean age: 62 years; 56% male) subjects were enrolled: 401 AF patients and 400 controls. All subjects completed a questionnaire and the associations between their green tea drinking habits and incidence of AF were assessed using the odds ratio (OR) and binary logistic regression. After multivariate adjustment, green tea intake presented as a protective factor against the incidence of AF (OR: 0.349, 95% CI: 0.253-0.483, P < 0.001). The green tea protection showed downward trend with increasing green tea intake (P for the trend= 0.001). Low frequency, low concentration, short-term tea consumption was classified as low-dose green tea intake. Green tea intake decreased the incidence of both paroxysmal AF (OR: 0.307, 95% CI: 0.216-0.436, P < 0.001) and persistent AF (OR: 0.355, 95% CI: 0.261-0.482, P < 0.001) and may be associated with a decreased incidence of AF. This study suggests that low-dose green tea intake strongly protects against AF.

Epigallocatechin-3-gallate modulates arrhythmogenic activity and calcium homeostasis of left atrium

BACKGROUND

Atrial fibrillation (AF) is the commonest sustained arrhythmia, and increases the risk of stroke, heart failure, and mortality. Calcium (Ca²⁺) overload and oxidative stress are thought to participate in the pathogenesis of AF. Epigallocatechin-3-gallate (EGCG) has an antioxidative effect and been shown to be beneficial in promoting cardiovascular health. However, it is not clear if EGCG directly modulates the electrophysiological characteristics and Ca²⁺ homeostasis of the left atrium (LA).

METHODS AND RESULTS

Conventional microelectrodes, whole-cell patch-clamp, and Fluo-3 fluorometric ratio technique were performed using the isolated rabbit LA preparations or isolated single LA cardiomyocytes before and after EGCG treatment. EGCG (0.01, 0.1, 1, and 10μM) which concentration-dependently decreased the APD₂₀ by 13±8%, 25±5%, 31±6%, and 37±5%, APD₅₀ by 9±8%, 22±6%, 32±7%, and 40±4%, and APD₉₀ by 2±12%, 9±8%, 24±10%, and 34±5% in LA preparations. EGCG (0.1μM) decreased the late sodium (Na⁺) current, L-type Ca²⁺ current, nickel-sensitive Na⁺-Ca²⁺ exchanger current, and transient outward current, but did not change the Na⁺ current and ultra-rapid delayed rectifier potassium current in LA cardiomyocytes. EGCG decreased intracellular Ca²⁺ transient and sarcoplasmic reticulum Ca²⁺ content in LA cardiomyocytes. Furthermore, EGCG decreased isoproterenol (ISO, 1μM)-induced burst firing. KT5823 (1μM) or KN93 (1μM) decreased the incidences of ISO-induced LA burst firing, which became lower with EGCG treatment. H89 (10μM) and KN92 (1μM) did not suppress the incidence of ISO-induced LA burst firing. However, EGCG decreased the incidences of ISO-induced LA burst firing in the presence of H89 or KN92.

CONCLUSION

EGCG directly regulates LA electrophysiological characteristics and Ca²⁺ homeostasis, and suppresses ISO-induced atrial arrhythmogenesis through inhibiting Ca²⁺/calmodulin or cGMP-dependent protein kinases.

Laminin Receptor-Avid Nanotherapeutic EGCg-AuNPs as a Potential Alternative Therapeutic Approach to Prevent Restenosis

In our efforts to develop new approaches to treat and prevent human vascular diseases, we report herein our results on the proliferation and migration of human smooth muscles cells (SMCs) and endothelial cells (ECs) using epigallocatechin-3-gallate conjugated gold nanoparticles (EGCg-AuNPs) as possible alternatives to drug coated stents. Detailed in vitro stability studies of EGCg-AuNPs in various biological fluids, affinity and selectivity towards SMCs and ECs have been investigated. The EGCg-AuNPs showed selective inhibitory efficacy toward the migration of SMCs. However, the endothelial cells remained unaffected under similar experimental conditions. The cellular internalization studies have indicated that EGCg-AuNPs internalize into the SMCs and ECs within short periods of time through laminin receptor mediated endocytosis mode. Favorable toxicity profiles and selective affinity toward SMCs and ECs suggest that EGCg-AuNPs may provide attractive alternatives to drug coated stents and therefore offer new therapeutic approaches in treating cardiovascular diseases.