Green Tea Intake and Parkinson's Disease Progression: A Mendelian Randomization Study

Predicting dementia in people with Parkinson's disease

Parkinson's disease (PD) exhibits a variety of symptoms, with approximately 25% of patients experiencing mild cognitive impairment and 45% developing dementia within ten years of diagnosis. Predicting this progression and identifying its causes remains challenging. Our study utilizes machine learning and multimodal data from the UK Biobank to explore the predictability of Parkinson's dementia (PDD) post-diagnosis, further validated by data from the Parkinson's Progression Markers Initiative (PPMI) cohort. Using Shapley Additive Explanation (SHAP) and Bayesian Network structure learning, we analyzed interactions among genetic predisposition, comorbidities, lifestyle, and environmental factors. We concluded that genetic predisposition is the dominant factor, with significant influence from comorbidities. Additionally, we employed Mendelian randomization (MR) to establish potential causal links between hypertension, type 2 diabetes, and PDD, suggesting that managing blood pressure and glucose levels in Parkinson's patients may serve as a preventive strategy. This study identifies risk factors for PDD and proposes avenues for prevention.

Therapeutic potential of green tea catechins on the development of Parkinson's disease symptoms in a transgenic A53T mouse model

Objectives: This study aimed to evaluate the effects of green tea catechins on the prevention of Parkinson's disease neurobehavioral symptoms and α-synuclein blood plasma concentration in a hemizygous transgenic A53T mouse model.Methods: Thirty 6-month-old male mice were randomly assigned to three groups (n = 10/group): control, low-dose, and high-dose, receiving green tea polyphenol (GTP) treatment in their drinking water at 0%, 0.5%, and 1.5%, respectively, over a 90-day period. The efficacy of ad libitum dosing was assessed by analyzing the bioaccumulation of tea catechins in urine samples collected from metabolic cages on days 0, 30, 60, and 90, using LC/Q-TOF analysis. PD-related behavioral impairments were measured with open field and rotarod performance tests on days 0, 45, and 90. On day 90, plasma α-synuclein levels were analyzed via enzyme-linked immunosorbent assay (ELISA) to assess treatment effects.Results: Circulating tea catechin metabolites were detected in treated groups by day 30, with levels progressively increasing through day 90. By day 90, control mice exhibited significant deficits in rotarod performance, while both low- and high-dose groups maintained or improved their maximum time on the rotarod. Open field testing indicated reduced anxiety-related behavior in control mice compared to treated groups. ELISA analysis revealed significantly lower circulating α-synuclein levels in high-dose mice compared to controls.Conclusion: Our findings indicate that sustained administration of tea catechins significantly reduces circulating α-synuclein levels in blood plasma, improves motor coordination in a dose-dependent manner, and modulates anxiety-related behaviors in a PD mouse model.

Investigating the causal impact of different types of physical activity on psychiatric disorders across life stages: A Mendelian randomization study

BACKGROUND

Psychiatric disorders, including attention-deficit hyperactivity disorder (ADHD), depression, anxiety disorders, and dementia, manifest differently across life stages, impacting cognitive, emotional, and behavioral health. Understanding the causal relationships between various types of physical activity and these disorders is crucial for developing targeted interventions.

METHODS

The summary level data from GWAS was utilized to conduct a two-sample Mendelian Randomization (MR) analysis. We assessed the potential causal relationships between different types of physical activity including light do it yourself (DIY) activities, heavy DIY activities, strenuous sports, and aerobic exercises/other exercises and the prevalence of psychiatric disorders (ADHD, depression, anxiety disorders, and dementia) across different life stages.

RESULTS

The MR analysis showed no causal relationship between light DIY activities and any of the psychiatric disorders studied. Heavy DIY activities showed a significant negative association with anxiety disorders but no links with ADHD, depression, or dementia. Strenuous sports did not demonstrate any causal relationship with the psychiatric disorders examined. Aerobic exercises were notably correlated with a reduced risk of depression, although no significant associations were found with ADHD, anxiety disorders, or dementia.

CONCLUSIONS

The findings indicate that heavy DIY activities might contribute to reducing anxiety disorders, while aerobic exercises potentially lower the risk of depression. These results emphasize the potential benefits of promoting specific types of physical activity to improve mental health outcomes across different life stages. Future research could further investigate the mechanisms underlying these relationships and consider diverse populations and objective measures of physical activity.

Exploring the hub Genes and Potential Mechanisms of Complement system-related Genes in Parkinson Disease: Based on Transcriptome Sequencing and Mendelian Randomization

An accurate diagnosis of Parkinson's disease (PD) remains challenging and the exact cause of the disease is unclean. The aims are to identify hub genes associated with the complement system in PD and to explore their underlying molecular mechanisms. Initially, differentially expressed genes (DEGs) and key module genes related to PD were mined through differential expression analysis and WGCNA. Then, differentially expressed CSRGs (DE-CSRGs) were obtained by intersecting the DEGs, key module genes and CSRGs. Subsequently, MR analysis was executed to identify genes causally associated with PD. Based on genes with significant MR results, the expression level and diagnostic performance verification were achieved to yield hub genes. Functional enrichment and immune infiltration analyses were accomplished to insight into the pathogenesis of PD. qRT-PCR was employed to evaluate the expression levels of hub genes. After MR analysis and related verification, CD93, CTSS, PRKCD and TLR2 were finally identified as hub genes. Enrichment analysis indicated that the main enriched pathways for hub genes. Immune infiltration analysis found that the hub genes showed significant correlation with a variety of immune cells (such as myeloid-derived suppressor cell and macrophage). In the qRT-PCR results, the expression levels of CTSS, PRKCD and TLR2 were consistent with those we obtained from public databases. Hence, we mined four hub genes associated with complement system in PD which provided novel perspectives for the diagnosis and treatment of PD.

Causal association between common rheumatic diseases and arrhythmia: a Mendelian randomization study

Background

Observational studies have suggested a link between rheumatic diseases and arrhythmias. However, these studies have been limited by confounding factors and reverse causality, leaving the causal relationship between rheumatic diseases and arrhythmias uncertain. This study addresses this inquiry using genetic evidence.

Methods

Selected single nucleotide polymorphisms (SNPs) from genome-wide association study (GWAS) data were employed as instrumental variables. Inverse variance weighting (IVW), MR-Egger regression, and the weighted median method were utilized in the two-sample Mendelian randomization analysis. Horizontal pleiotropy was identified and rectified through the MR-PRESSO test and MR-Egger regression. The stability and reliability of the Mendelian randomization results were appraised using the remain-one method, Cochran Q-test, and funnel plot. Odds ratios (OR) were utilized to assess the causal relationship between six rheumatic diseases and five types of arrhythmias.

Results

The Inverse Variance Weighted (IVW) method indicated a significant association between rheumatoid arthritis (RA) and an elevated risk of right bundle branch block (RBBB) (OR: 1.10, 95% CI: 1.02-1.18, p = 0.009). Additionally, gout was significantly correlated with an augmented risk of RBBB (OR: 1.28, 95% CI: 1.09-1.51, p = 0.003). Conversely, dermatomyositis (DM) exhibited a negative association with the risk of atrioventricular block (AVB) (OR: 0.94, 95% CI: 0.90-0.99, p = 0.020). No significant associations were observed between other rheumatic diseases and arrhythmias.

Conclusion

A two-sample Mendelian Randomization (MR) study provides data indicating that in European populations, a genetically predicted gout or rheumatoid arthritis (RA) may increase the incidence of right bundle branch block (RBBB). To clarify and investigate the processes behind these causal links, more research is necessary. Because racial genetic variability exists, care should be used when interpreting our findings.

Evaluating the effect of green tea intake on cardiovascular diseases: A Mendelian randomization study in European and East Asian populations

Previous research shows that more than 70% of cardiovascular diseases (CVDs) are attributed to modifiable risk factors. Here, we investigated relationship between consumption of green tea in European and East Asian populations and risk of CVDs using Mendelian randomization (MR). Instrumental variables for green tea intake were obtained from genome-wide association studies (GWASs) of 64,949 Europeans and 152,653 East Asians. GWASs for CVDs were derived from UK BioBank and BioBank Japan projects. The main method selected for MR analysis was either the inverse variance weighted (IVW) or Wald ratio, depending on the quantity of single nucleotide polymorphisms. Furthermore, we performed sensitivity analyses to confirm the reliability of the findings. Based on the results of IVW, there is no causal relationship between consumption of green tea and risk of 4 CVDs among Europeans (atrial fibrillation: OR = 1.000, 95% CI: 0.995-1.005, P = .910; heart failure: OR = 1.003, 95% CI: 0.994-1.012, P = .542; ischemic stroke: OR = 1.002, 95% CI: 0.993-1.011, P = .690; coronary artery disease: OR = 1.001, 95% CI: 0.996-1.007, P = .677). Sensitivity analyses and supplementary MR analyses also verify the robustness of the findings. Likewise, there was no correlation between the consumption of green tea and the occurrence of CVDs in East Asians. The consumption of green tea is not associated with a reduced risk of CVDs in populations from Europe and East Asia. This means that those who are trying to reduce their risk of CVDs by drinking more green tea may not benefit from doing so.

Neuroprotective effect of green tea extract (-)-epigallocatechin-3-gallate in a preformed fibril-induced mouse model of Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disease characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra (SN). The main bioactive component of green tea polyphenols (-)-epigallocatechin-3-gallate (EGCG) exerts protective effects against diseases such as neurodegenerative diseases and cancer. Therefore, this study investigated the effect of EGCG on the amelioration of neural damage in a chronic PD mouse model induced by α-synuclein preformed fibrils (α-syn-PFFs). A total of 20 C57BL/6J female mice were randomly divided into 3 groups: control group (saline, n = 6), model group (PFFs, n = 7), and prevention group (EGCG+PFFs, n = 7). A chronic PD mouse model was obtained by the administration of α-syn-PFFs by stereotaxic localization in the striatum. Behavioral tests were performed to evaluate PD-related anxiety-like behavior and motor impairments in the long-term PD progression. Tyrosine hydroxylase (TH) immuno-positive neurons and Ser129-phosphorylated α-syn (p-α-syn) were identified by immunohistochemistry. Pro-inflammatory and anti-inflammatory cytokines were measured by real-time quantitative PCR. EGCG pretreatment reduced anxiety-like behavior and motor impairments as revealed by the long-term behavioral test (2 weeks, 1 month, 3 months, and 6 months) on PD mice. EGCG also ameliorated PFF-induced degeneration of TH immuno-positive neurons and accumulation of p-α-syn in the SN and striatum at 6 months. Additionally, EGCG reduced the expression of pro-inflammatory cytokines while promoting the release of anti-inflammatory cytokines. EGCG exerts a neuroprotective effect on long-term progression of the PD model.

Risk factors associated with age at onset of Parkinson's disease in the UK Biobank

Substantial evidence shown that the age at onset (AAO) of Parkinson's disease (PD) is a major determinant of clinical heterogeneity. However, the mechanisms underlying heterogeneity in the AAO remain unclear. To investigate the risk factors with the AAO of PD, a total of 3156 patients with PD from the UK Biobank were included in this study. We evaluated the effects of polygenic risk scores (PRS), nongenetic risk factors, and their interaction on the AAO using Mann-Whitney U tests and regression analyses. We further identified the genes interacting with nongenetic risk factors for the AAO using genome-wide environment interaction studies. We newly found physical activity (P < 0.0001) was positively associated with AAO and excessive daytime sleepiness (P < 0.0001) was negatively associated with AAO, and reproduced the positive associations of smoking and non-steroidal anti-inflammatory drug intake and the negative association of family history with AAO. In the dose-dependent analyses, smoking duration (P = 1.95 × 10-6), coffee consumption (P = 0.0150), and tea consumption (P = 0.0008) were positively associated with AAO. Individuals with higher PRS had younger AAO (P = 3.91 × 10-5). In addition, we observed a significant interaction between the PRS and smoking for AAO (P = 0.0316). Specifically, several genes, including ANGPT1 (P = 7.17 × 10-7) and PLEKHA6 (P = 4.87 × 10-6), may influence the positive relationship between smoking and AAO. Our data suggests that genetic and nongenetic risk factors are associated with the AAO of PD and that there is an interaction between the two.

Causal association between adiponectin and the risk of Alzheimer's disease: A Mendelian randomization study

Background

Numerous observational studies have revealed that circulating adiponectin (ADPN) is associated with Alzheimer's disease (AD) risk. However, the causality remains unknown. We aimed to assess the causality of circulating ADPN on AD risk using Mendelian randomization (MR).

Methods

Fourteen single nucleotide polymorphisms (SNPs) significantly associated with ADPN were selected from publicly available genetic abstract data. We applied these SNPs to two recent large-scale genome-wide association studies (GWAS) of AD, one from the FinnGen consortium and the other from a large meta-analysis. The inverse variance weighted method, MR-Egger method, the weighted median method, the Cochran Q statistic, the MR-Pleiotropy Residual Sum and Outlier methods, and the leave-one-out analysis were applied for MR analyses.

Results

In MR analysis, no significant genetic association was found between plasma ADPN levels and AD risk by analyzing the FinnGen consortium GWAS database in the inverse variance weighted method [odds ratio (OR): 0.874, 95% confidence interval (CI): 0.701-1.089, p = 0.230], MR-Egger (OR: 0.944, 95% CI: 0.692-1.288, p = 0.721), and weighted median method (OR: 0.900, 95% CI: 0.678-1.194, p = 0.449). Additionally, the same analysis was conducted for the meta-analysis database, and we found no significant association (OR: 1.000, 95% CI: 0.999-1.001, p = 0.683).

Conclusion

Our findings reveal no significant causal association between circulating ADPN and AD risk.