Association of Green Tea Consumption and Coronary Arterial Disease Risk in a Chinese Population in Guangzhou

Green tea consumption and the risk of coronary heart disease: A systematic review and meta-analysis of cohort studies

BACKGROUND AND AIMS

Conflicting evidence exists regarding the association between green tea consumption and the risk of coronary heart disease (CHD). We performed a meta-analysis to determine whether an association exists between them in cohort studies.

METHODS AND RESULTS

We searched the PubMed and EMBASE databases for studies conducted until September 2022. Prospective cohort studies that provided relative risk (RR) estimates with 95% confidence intervals (CIs) for the association were included. Study-specific risk estimates were combined using a random-effects model. A total of seven studies, with 9211 CHD cases among 772,922 participants, were included. We observed a nonlinear association between green tea consumption and the risk of CHD (P for nonlinearity = 0.0009). Compared with nonconsumers, the RRs (95% CI) of CHD across levels of green tea consumption were 0.89 (0.83, 0.96) for 1 cup/day (1 cup = 300 ml), 0.84 (0.77, 0.93) for 2 cups/day, 0.85 (0.77, 0.92) for 3 cups/day, 0.88 (0.81, 0.96) for 4 cups/day, and 0.92 (0.82, 1.04) for 5 cups/day.

CONCLUSIONS

This updated meta-analysis of studies from East Asia suggests that green tea consumption may be associated with a reduced risk of CHD, especially among those with low-to-moderate consumption. Additional cohorts are still needed before we could draw a definitive conclusion.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022357687.

Association between tea consumption and prevention of coronary artery disease: A systematic review and dose-response meta-analysis

Background

Evidence from previous studies reporting on the relationship between tea consumption and its preventive effect on coronary artery disease (CAD) has conflicting outcomes. With the accumulation of new clinical evidence, we conducted this meta-analysis to assess tea consumption and CAD risk.

Methods

We searched PubMed, EMBASE, Cochrane Library, and Medline databases for published observational studies from their inception to May 2022. A random-effects model was used to calculate risk ratios with 95% confidence intervals. We also conducted linear and non-linear dose-response meta-analyses to analyze the association. We regarded that one cup equals 237 mL. Subgroup analyses and univariate meta-regression were conducted to explore the source of heterogeneity.

Results

A total of 35 studies, including 24 on green tea and 11 on black tea consumption, were included in this meta-analysis. An inverse association for the risk of CAD was observed for black tea (RR: 0.85; 95% CI: 0.76, 0.96) and green tea (RR: 0.93; 95% CI: 0.88, 0.99). The dose-response meta-analysis showed that drinking less than four cups of black tea daily may effectively prevent CAD, while more than 4-6 cups/d will promote disease risk. Furthermore, the dose-response relationship between green tea consumption and the prevention of CAD showed that the risk of CAD gradually decreased as green tea consumption increased. We also demonstrated that the more cups of green tea consumed, the lower the risk of CAD. In the subgroup analysis by continent, a significant negative correlation between CAD risk and green tea consumption was observed in the Asian population (RR: 0.92; 95% CI: 0.85, 0.99) but not in the western population [North America (RR: 0.97; 95% CI: 0.92, 1.03), Europe/Oceana (RR: 0.91; 95% CI: 0.78, 1.07)].

Conclusions

Higher green tea consumption was associated with reduced CAD risk, but drinking more than 4-6 cups of black tea per day may increase the risk. This study offers new insight into the relationship between tea consumption and its preventive effect on CAD. However, further large prospective cohort studies are needed to validate these findings.

Systematic review registration

The protocol of this systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) system (CRD42022348069).

Systems Approach to Integrating Preclinical Apolipoprotein E-Knockout Investigations Reveals Novel Etiologic Pathways and Master Atherosclerosis Network in Humans

OBJECTIVE

Animal models of atherosclerosis are used extensively to interrogate molecular mechanisms in serial fashion. We tested whether a novel systems biology approach to integration of preclinical data identifies novel pathways and regulators in human disease. Approach and Results: Of 716 articles published in ATVB from 1995 to 2019 using the apolipoprotein E knockout mouse to study atherosclerosis, data were extracted from 360 unique studies in which a gene was experimentally perturbed to impact plaque size or composition and analyzed using Ingenuity Pathway Analysis software. TREM1 (triggering receptor expressed on myeloid cells) signaling and LXR/RXR (liver X receptor/retinoid X receptor) activation were identified as the top atherosclerosis-associated pathways in mice (both P<1.93×10-4, TREM1 implicated early and LXR/RXR in late atherogenesis). The top upstream regulatory network in mice (sc-58125, a COX2 inhibitor) linked 64.0% of the genes into a single network. The pathways and networks identified in mice were interrogated by testing for associations between the genetically predicted gene expression of each mouse pathway-identified human homolog with clinical atherosclerosis in a cohort of 88 660 human subjects. Homologous human pathways and networks were significantly enriched for gene-atherosclerosis associations (empirical P<0.01 for TREM1 and LXR/RXR pathways and COX2 network). This included 12(60.0%) TREM1 pathway genes, 15(53.6%) LXR/RXR pathway genes, and 67(49.3%) COX2 network genes. Mouse analyses predicted, and human study validated, the strong association of COX2 expression (PTGS2) with increased likelihood of atherosclerosis (odds ratio, 1.68 per SD of genetically predicted gene expression; P=1.07×10-6).

CONCLUSIONS

PRESCIANT (Preclinical Science Integration and Translation) leverages published preclinical investigations to identify high-confidence pathways, networks, and regulators of human disease.

Multi-residue analytical method development and risk assessment of 56 pesticides and their metabolites in tea by chromatography tandem mass spectroscopy

A modified QuEChERS method coupled to chromatography tandem mass spectroscopy was established and used to identify 56 pesticides and 21 metabolites residues in tea samples. The average recoveries for the target compounds ranged from 71% to 109% with RSDs of 1-17%. Pesticides and metabolites residues in 248 tea samples from China were investigated by the developed method, and the dietary intake risk for consumers was estimated. The results showed that 36 pesticides and 14 metabolites were detected with concentrations of 0.0050-7.7 mg/kg. There are unlikely to present a public health concern for Chinese consumers. The acute risk of pesticides would be exaggerated when calculated by the residue level in tea instead of tea infusion. The unauthorized and banned pesticide contributed to the chronic and acute hazard index by 68% and 36%, respectively. The cumulative risk of residual pesticides and their metabolites on human health deserve further attention.

Epigallocatechin-3-gallate protects cardiomyocytes from hypoxia-reoxygenation damage via raising autophagy related 4C expression

Myocardial ischemia/reperfusion (I/R) injury is a serious issue during the therapy of myocardial infarction. Herein, we explored the beneficial influence of Epigallocatechin-3-gallate (EGCG) on hypoxia/reoxygenation (H/R)-stimulated cardiomyocyte H9c2 cells damage, along with possible internal molecular mechanism related autophagy related 4C (ATG4C). H9c2 cells were subjected to H/R stimulation and/or EGCG treatment. ATG4C mRNA expression was measured via q-PCR assay. ATG4C overexpression plasmid (OE-ATG4C) was transfected to arise ATG4C level. Cell viability, apoptosis, reactive oxygen species (ROS) production, ATP level were tested via CCK-8 assay, Annexin V-FITC/PI staining, DCFH-DA staining and ATP Assay Kit, respectively. Western blotting was performed to test Cleaved-caspase 3, Cleaved-caspase 9, cytochrome C, and LC3B protein levels. H/R stimulation resulted in H9c2 cell viability loss, promoted cell apoptosis, and ROS overproduction, as well as lowered ATP level in cells. EGCG treatment alleviated H/R-resulted H9c2 cell viability loss, cell apoptosis, ROS overproduction, and reduction of ATP level. Moreover, H/R stimulation reduced the ATG4C expression in H9c2 cells, while EGCG raised the ATG4C expression. Overexpression of ATG4C strengthened the beneficial influence of EGCG on H/R-stimulated H9c2 cell viability, apoptosis and ROS production. Besides, ATG4C overexpression weakened the H/R-stimulated H9c2 cell autophagy via reducing LC3B II/I expression. EGCG exerted beneficial influence on H/R-stimulated cardiomyocytes, which protected cardiomyocytes from H/R-stimulated viability loss, apoptosis, and ROS overproduction via enhancing ATG4C expression.

Protective Effect of Epigallocatechin Gallate on Endothelial Disorders in Atherosclerosis

Healthy vascular endothelial cells regulate vascular tone and permeability, prevent vessel wall inflammation, enhance thromboresistance, and contribute to general vascular health. Furthermore, they perform important functions including the production of vasoactive substances such as nitric oxide (NO) and endothelium-derived hyperpolarizing factors, as well as the regulation of smooth muscle cell functions. Conversely, vascular endothelial dysfunction leads to atherosclerosis, thereby enhancing the risk of stroke, myocardial infarction, and other cardiovascular diseases (CVDs). Observational studies and randomized trials showed that green tea intake was inversely related to CVD risk. Furthermore, evidence indicates that epigallocatechin gallate (EGCG) found in green tea might exert a preventive effect against CVDs. EGCG acts as an antioxidant, inducing NO release and reducing endothelin-1 production in endothelial cells. EGCG enhances the bioavailability of normal NO by reducing levels of the endogenous NO inhibitor asymmetric dimethylarginine. Furthermore, it inhibits the enhanced expression of adhesion molecules such as vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 and attenuates monocyte adhesion. In addition, EGCG prevents enhanced oxidative stress through the Nrf2/HO-1 pathway. These effects indicate that it might prevent the production of reactive oxygen species, inhibit inflammation, and reduce endothelial cell apoptosis during the initial stages of atherosclerosis. The current review summarizes recent research in this area and discusses novel findings regarding the protective effect of EGCG on endothelial dysfunction and CVDs in general.