Associations of plasma TMAO and its precursors with stroke risk in the general population: A nested case-control study

Association of the gut microbe-dependent trimethylamine N-oxide and its precursors with risk of hypertension: a cross-sectional study in rural northeastern China

BACKGROUND AND AIM

This study investigated the relationship between trimethylamine N-oxide (TMAO), its precursors (choline, betaine, and carnitine), and the prevalence of hypertension in rural northeastern China.

METHODS AND RESULTS

Conducted in 2019, the cross-sectional study involved 1,899 adults aged 35 and older, with serum levels of TMAO and its precursors quantified using high-performance liquid chromatography-mass spectrometry. Hypertension was defined according to blood pressure measurements or the use of antihypertensive medications, based on the 2018 Chinese Hypertension Guidelines. Logistic regression models were utilized to assess the associations between TMAO, its precursors, and hypertension, adjusting for potential confounders such as age, sex, smoking status, and physical activity. The results revealed a significant association between TMAO concentrations and the prevalence of hypertension. Participants in the highest quartile of TMAO (>7.75 μmol/L) exhibited a 36 % increased risk of hypertension (OR = 1.360, 95 % CI: 1.043-1.772, P = 0.023). Choline also showed a positive association with hypertension (OR = 1.426, 95 % CI: 1.092-1.863, P = 0.009), while no significant association was found for betaine. Conversely, carnitine was negatively associated with hypertension risk in the highest quartile. Subgroup analyses indicated that these associations varied by age, gender, and education level.

CONCLUSIONS

Elevated serum levels of TMAO and choline were associated with an increased risk of hypertension. Modulating TMAO metabolism could aid in the prevention of hypertension in the future.

Association between L-α glycerylphosphorylcholine use and delayed dementia conversion: A nationwide longitudinal study in South Korea

BACKGROUND

Alzheimer's disease and vascular dementia are two of the most common causes of dementia. While early diagnosis and intervention are crucial, available treatments and research concerning the mild cognitive impairment stage remain limited. This study aimed to evaluate the real-world effectiveness and safety of L-α glycerylphosphorylcholine in this context.

OBJECTIVES

To investigate the impact of L-α glycerylphosphorylcholine on the risk of conversion from mild cognitive impairment to Alzheimer's disease dementia and vascular dementia, as well as its influence on stroke risk DESIGN: A nationwide, population-based cohort study SETTING: Data from South Korea's National Health Insurance Service PARTICIPANTS: Overall, 508,107 patients newly diagnosed with mild cognitive impairment between 2013 and 2016 were included.

INTERVENTION

Patients were classified as users or non-users of L-α glycerylphosphorylcholine based on prescription records.

MEASUREMENTS

The primary outcomes were the risk of progression to Alzheimer's disease dementia and vascular dementia. Stroke risk was examined as a secondary outcome. A time-dependent Cox regression analysis was used to adjust for demographic and clinical factors.

RESULTS

Compared to non-users, L-α glycerylphosphorylcholine users had a lower risk of progression to Alzheimer's disease dementia (hazard ratio = 0.899, 95 % confidence interval: 0.882-0.918) and vascular dementia (hazard ratio = 0.832, 95 % confidence interval: 0.801-0.865) within 2,435,924 and 662,281.6 person-years, respectively. In patients under 65, L-α glycerylphosphorylcholine significantly reduced the risk of progression to Alzheimer's and vascular dementia. Stroke risk significantly decreased in patients who did not progress to dementia but not in those who did.

CONCLUSIONS

L-α Glycerylphosphorylcholine reduces dementia conversion and stroke risk in patients with mild cognitive impairment, making it a viable early intervention. Future large-scale randomized controlled studies should examine its effects on other dementia subtypes and long-term cognitive outcomes.

Choline metabolism in ischemic stroke: An underappreciated "two-edged sword"

Ischemic stroke (IS) is an important cause of death and disability worldwide, but the molecular mechanisms involved are not fully understood. In this context, choline metabolism plays an increasingly important role in IS due to its multifaceted mechanisms involving neuroprotection, neuroregeneration, inflammatory response, immune regulation, and long-term health effects. With the deepening of the research on choline and its metabolites, such as trimethylamine-N-oxide (TMAO), scientists have gradually realized its key role in the occurrence, development and potential treatment of IS. This review summarizes the importance of choline in neuroprotection and long-term disease management, highlighting the complexity of choline metabolism affecting cerebrovascular health through gut microbes. Although choline and its metabolites exhibit a protective effect, excessive intake and increases in some metabolites may confer risk, suggesting the need to carefully balance dietary choline intake. The purpose of this review is to integrate the existing research results and provide a theoretical basis for further exploring the mechanism, prognosis evaluation and clinical intervention of choline metabolism in ischemic IS, hoping to provide a new perspective and enlightenment for the formulation of effective stroke prevention and treatment strategies, and promote a comprehensive understanding of heart and brain health and optimize intervention methods.

Associations of Plasma Gut Microbiota-Derived TMAO and Precursors in Early Pregnancy with Gestational Diabetes Mellitus Risk: A Nested Case-Control Study

Objectives: Gut microbiota-derived metabolites-trimethylamine N-oxide (TMAO) and its precursors choline, betaine, and carnitine-have been linked to various health outcomes. However, their role in gestational diabetes mellitus (GDM) remains unclear due to inconsistent findings. This study aims to investigate the associations between maternal plasma concentrations of these metabolites during early pregnancy and the risk of GDM. Methods: A nested case-control study was performed in the Shanghai Birth Cohort. GDM cases and non-GDM controls were matched according to maternal age at a ratio of 1:4. Three hundred twenty-one identified GDM cases and 1284 controls were included. Maternal plasma concentrations of TMAO and its precursors were measured between 12 and 16 weeks of gestation in early pregnancy using high-performance liquid chromatography-tandem mass spectrometry. Conditional logistic regression models were applied to assess associations between metabolite levels and GDM risk and to calculate odds ratios (ORs) and their 95% confidence intervals (CIs). Multivariate linear regressions evaluated relationships between metabolite concentrations and glycemic indicators. Stratified and sensitivity analyses were conducted to ensure robustness. Results: Maternal plasma levels of TMAO, choline, betaine, and carnitine in early pregnancy were 1.95 μmol/L (IQR, 1.16-3.20), 9.25 μmol/L (IQR, 7.31-11.98), 20.51 μmol/L (IQR, 16.92-24.79), and 17.13 μmol/L (IQR, 13.33-21.16), respectively. Betaine and carnitine were significantly higher in GDM cases (p = 0.002 and p = 0.042, respectively). No significant associations were identified between TMAO levels and GDM risk and glycemic indicators. Each SD increase in choline was associated with a 16% higher GDM risk (OR = 1.16, 95% CI: 1.01, 1.34, p = 0.039), while increased betaine and carnitine levels were linked to a 19% (OR = 0.81, 95% CI: 0.70, 0.95; p = 0.010) and 20% (OR = 0.80, 95% CI: 0.69, 0.94; p = 0.007) lower risk, respectively. Restricted cubic spline models showed no evidence of non-linear relationships (pfor non-linearity > 0.05). Interaction analyses indicated that the protective effect of betaine may be more pronounced in parous women. Conclusions: Higher early pregnancy levels of betaine and carnitine were associated with a reduced GDM risk, while elevated choline levels increased the risk. The protective association between betaine and GDM was more pronounced in parous women. No significant relationship was found between TMAO and GDM. The roles of choline, betaine, and carnitine in glucose metabolism warrant further investigation.

The Role of Gut Microbiota-Derived Trimethylamine N-Oxide in the Pathogenesis and Treatment of Mild Cognitive Impairment

Mild cognitive impairment (MCI) represents a transitional stage between normal aging and dementia, often considered critical for dementia prevention. Despite its significance, no effective clinical treatment for MCI has yet been established. Emerging evidence has demonstrated a strong association between trimethylamine-N-oxide (TMAO), a prominent metabolite derived from the gut microbiota, and MCI, highlighting its potential as a biomarker and therapeutic target. TMAO has been implicated in increasing MCI risk through its influence on factors such as hypertension, cardiovascular disease, depression, diabetes, and stroke. Moreover, it contributes to MCI by promoting oxidative stress, disrupting the blood-brain barrier, impairing synaptic plasticity, inducing inflammation, causing mitochondrial metabolic disturbances, and facilitating abnormal protein aggregation. This review further explores therapeutic strategies targeting TMAO to mitigate MCI progression.

Systematic Mendelian Randomization Exploring Druggable Genes for Hemorrhagic Strokes

Patients with hemorrhagic stroke have high rates of morbidity and mortality, and drugs for prevention are very limited. Mendelian randomization (MR) analysis can increase the success rate of drug development by providing genetic evidence. Previous MR analyses only analyzed the role of individual drug target genes in hemorrhagic stroke; therefore, we used MR analysis to systematically explore the druggable genes for hemorrhagic stroke. We sequentially performed summary-data-based MR analysis and two-sample MR analysis to assess the associations of all genes within the database with intracranial aneurysm, intracerebral hemorrhage, and their subtypes. Validated genes were further analyzed by colocalization. Only genes that were positive in all three analyses and were druggable were considered desirable genes. We also explored the mediators of genes affecting hemorrhagic stroke incidence. Finally, the associations of druggable genes with other cardiovascular diseases were analyzed to assess potential side effects. We identified 56 genes that significantly affected hemorrhagic stroke incidence. Moreover, TNFSF12, SLC22A4, SPARC, KL, RELT, and ADORA3 were found to be druggable. The inhibition of TNFSF12, SLC22A4, and SPARC can reduce the risk of intracranial aneurysm, subarachnoid hemorrhage, and intracerebral hemorrhage. Gene-induced hypertension may be a potential mechanism by which these genes cause hemorrhagic stroke. We also found that blocking these genes may cause side effects, such as ischemic stroke and its subtypes. Our study revealed that six druggable genes were associated with hemorrhagic stroke, and the inhibition of TNFSF12, SLC22A4, and SPARC had preventive effects against hemorrhagic strokes.

Associations of plasma arginine, homoarginine, and ADMA/SDMA levels with risk of ischemic stroke: A nested case-control study

BACKGROUND AND AIMS

Previous studies have linked aberrant nitric oxide (NO) metabolism with vascular diseases. Although arginine, homoarginine, asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA) are involved in NO metabolic pathways, their associations with ischemic stroke (IS) remain unclear.

METHODS AND RESULTS

We conducted a case-control study nested within the Prospective Follow-up Study on Cardiovascular Morbidity and Mortality in China (PFS-CMMC) (2013-2018, n = 16,457; median follow-up time: 5.3 y), which included 321 incident cases of IS and 321 controls matched by age and sex. Plasma arginine, homoarginine, ADMA/SDMA were measured by ultrahigh performance liquid chromatography-tandem mass spectrometry. Conditional logistic regression analyses were used to calculate odds ratios (ORs) and their 95% confidence intervals (CIs) for the association between the plasma metabolites and IS risk. After adjustment for body mass index, educational attainment, smoking, hypertension, hyperlipidemia, diabetes, and family history of stroke, the OR of IS risk for the highest versus the lowest quartile was 2.46 (95% CI: 1.39-4.35, P trend = 0.004) for homoarginine and 2.22 (95% CI: 1.24-3.97, P trend = 0.003) for ADMA/SDMA. Spline regression analyses indicated positive dose-response relationships of homoarginine and ADMA/SDMA with the IS risk (both P for linearity <0.05). No significant association was observed between plasma arginine and IS risk.

CONCLUSIONS

Elevated plasma levels of homoarginine and ADMA/SDMA were associated with a higher risk of IS. Our novel findings suggest a role of NO metabolism in the pathogenesis of IS.

Novel Insight into the Modulatory Effect of Traditional Chinese Medicine on Cerebral Ischemia-Reperfusion Injury by Targeting Gut Microbiota: A Review

Cerebral ischemia-reperfusion injury (CIRI) is clinically characterized by high rates of morbidity, disability, mortality, and recurrence as well as high economic burden. The clinical manifestations of CIRI are often accompanied by gastrointestinal symptoms such as intestinal bacterial dysbiosis and gastrointestinal bleeding. Gut microbiota plays an important role in the pathogenesis of CIRI, and its potential biological effects have received extensive attention. The gut microbiota not only affects intestinal barrier function but also regulates gastrointestinal immunity and host homeostasis. Traditional Chinese medicine (TCM), a multi-component and multi-targeted drug, has shown remarkable effects and few adverse reactions in the prevention and treatment of CIRI. Notably, the effect of TCM on CIRI by regulating gut microbiota and maintaining gastrointestinal homeostasis has gradually become a hot topic. This review summarizes the functional role of the gut microbiota in the development and progression of CIRI and the therapeutic effects of TCM on CIRI by improving gut microbiota dysbiosis, affecting gut microbiota metabolism, and maintaining host immunity. The active ingredients of TCM used for the treatment of CIRI in relevant studies were saponins, triterpenoids, phenolics, and alkaloids. In addition, the clinical effects of TCM used to treat CIRI were briefly discussed. This review established the clinical significance and development prospects of TCM-based CIRI treatments and provided the necessary theoretical support for the further development of TCM resources for the treatment of CIRI.

Serum trimethylamine N-oxide and its precursors are associated with the occurrence of mild cognition impairment as well as changes in neurocognitive status

Background

This study aims to examine the association between gut microbe-dependent trimethylamine N-oxide (TMAO) and its precursors (choline, betaine, and carnitine) levels and mild cognition impairment (MCI), alongside changes in the Chinese version of the Montreal Cognitive Assessment-Basic (ΔMoCA-BC) score in rural adults.

Methods

Drawing data from a large-scale epidemiological study conducted in rural areas of Fuxin County, Liaoning Province, China. 1,535 participants free from brain-related ailments were initially surveyed. MCI was assessed through the MoCA-BC score. Logistic regression models and restricted cubic spline were used to investigate the association between TMAO and its precursors levels and MCI. Additionally, the association between TMAO and its precursors levels and ΔMoCA-BC was analyzed using a generalized linear model in the longitudinal study.

Results

The average age of the study participants was 58.6 ± 9.4 years and the prevalence rate of MCI was 34.5%. With the second quartile as the reference in the logistic regression model, the OR for risk of MCI in the highest quartile for TMAO, betaine, and carnitine was 1.685 (95% CI: 1.232-2.303, p = 0.001), 2.367 (95% CI: 1.722-3.255, p < 0.001), and 2.239 (95% CI: 1.742-3.295, p < 0.001), respectively. The OR of choline for the highest versus lowest quartile was 2.711 (95% CI: 2.012-3.817, p < 0.001) for the risk of MCI. We find a J-shaped association between betaine (P non-linear = 0.001) and carnitine (P non-linear = 0.003) levels and MCI. Furthermore, TMAO and its precursors levels were associated with ΔMoCA-BC in the third and fourth quartiles group (All p < 0.05).

Conclusion

The findings suggest the existence of an optimal concentration range for serum levels of TMAO, betaine, and carnitine that mitigates MCI risk, paving the way for enhanced dietary interventions aimed at preventing and treating MCI.

Microbiome-Derived Trimethylamine N-Oxide (TMAO) as a Multifaceted Biomarker in Cardiovascular Disease: Challenges and Opportunities

Biomarkers play a crucial role in various stages of disease management, including screening, diagnosis, prediction, prognosis, treatment, and safety monitoring. Although they are powerful tools in disease diagnosis, management, and drug development, identifying and validating reliable biomarkers remains a significant challenge. Among potential microbiome-derived biomarkers, trimethylamine N-oxide (TMAO) has gained notable attention for its link to atherosclerosis and cardiovascular risk. However, despite the growing body of research on TMAO, its practical application in clinical settings for disease management and patient outcome enhancement is still not a reality. This paper presents recent data on the utility of TMAO as a cardiovascular biomarker, categorized by its various roles: diagnostic, prognostic, susceptibility/risk, monitoring, pharmacodynamic/response, predictive, and safety. It also briefly discusses research on TMAO's potential role in cardiovascular disease development. While TMAO shows promise, particularly in prognostic applications, its reliability as a biomarker has been inconsistent across studies. These variances may result from several confounding factors that affect TMAO plasma levels, including diet, kidney function, and demographic variables. The review aims to elucidate the specific contexts in which TMAO can be valuable, potentially leading to more personalized and effective management of cardiovascular disease.

Gut Microbe-Generated Metabolite Trimethylamine-N-Oxide and Ischemic Stroke

Trimethylamine-N-oxide (TMAO) is a gut microbiota-derived metabolite, the production of which in vivo is mainly regulated by dietary choices, gut microbiota, and the hepatic enzyme flavin monooxygenase (FMO), while its elimination occurs via the kidneys. The TMAO level is positively correlated with the risk of developing cardiovascular diseases. Recent studies have found that TMAO plays an important role in the development of ischemic stroke. In this review, we describe the relationship between TMAO and ischemic stroke risk factors (hypertension, diabetes, atrial fibrillation, atherosclerosis, thrombosis, etc.), disease risk, severity, prognostic outcomes, and recurrence and discuss the possible mechanisms by which they interact. Importantly, TMAO induces atherosclerosis and thrombosis through lipid metabolism, foam cell formation, endothelial dysfunction (via inflammation, oxidative stress, and pyroptosis), enhanced platelet hyper-reactivity, and the upregulation and activation of vascular endothelial tissue factors. Although the pathogenic mechanisms underlying TMAO's aggravation of disease severity and its effects on post-stroke neurological recovery and recurrence risk remain unclear, they may involve inflammation, astrocyte function, and pro-inflammatory monocytes. In addition, this paper provides a summary and evaluation of relevant preclinical and clinical studies on interventions regarding the gut-microbiota-dependent TMAO level to provide evidence for the prevention and treatment of ischemic stroke through the gut microbe-TMAO pathway.

Association of trimethylamine oxide and its precursors with cognitive impairment: a systematic review and meta-analysis

Objectives

The role of trimethylamine oxide (TMAO) in patients with cognitive impairment remains controversial. This study aimed to assess the association between TMAO and its precursors and the prevalence of cognitive impairment.

Methods

PubMed, Embase, and Web of Science databases were searched for studies that met the inclusion criteria from their inception to 14 September 2024, and references were manually searched to identify any additions. Odds ratio (OR) was assessed by random-effects modeling, subgroup analyses to identify potential sources of heterogeneity, and the Newcastle-Ottawa Scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ) Inventory for qualitative evaluation.

Results

Nine studies involving 82,246 participants were included in the analysis. Meta-analyses suggested that elevated TMAO levels were strongly associated with an increased risk of cognitive impairment (OR: 1.39, 95% confidence interval [95%CI]: 1.09-1.77, p < 0.05, I2:60%), and consistent results were obtained across all subgroups examined and sensitivity analyses. However, in the TMAO dose-response meta-analysis and TMAO precursor meta-analyses, the results were not significantly different (dietary choline: OR: 0.93, 95%CI: 0.78-1.10, p = 0.385, I2:68%, plasma choline: OR: 0.65, 95%CI: 0.41-1.02, p = 0.063, I2:76%, plasma betaine: OR: 0.74, 95%CI: 0.52-1.05, p = 0.094, I2:61%).

Conclusion

We found that high TMAO concentrations were positively associated with the risk of cognitive impairment. TMAO is expected to be a potential risk predictor and therapeutic target for cognitive impairment. However, more high-quality studies are needed to further investigate the dose relationship between circulating TMAO concentrations and cognitive impairment.

Systematic review registration

PROSPERO, identifier: CRD42023464543.

Low-Molecular-Weight Compounds Produced by the Intestinal Microbiota and Cardiovascular Disease

Cardiovascular disease is the main cause of mortality in industrialized countries, with over 500 million people affected worldwide. In this work, the roles of low-molecular-weight metabolites originating from the gut microbiome, such as short-chain fatty acids, hydrogen sulfide, trimethylamine, phenylacetic acid, secondary bile acids, indoles, different gases, neurotransmitters, vitamins, and complex lipids, are discussed in relation to their CVD-promoting or preventing activities. Molecules of mixed microbial and human hepatic origin, such as trimethylamine N-oxide and phenylacetylglutamine, are also presented. Finally, dietary agents with cardioprotective effects, such as probiotics, prebiotics, mono- and poly-unsaturated fatty acids, carotenoids, and polyphenols, are also discussed. A special emphasis is given to their gut microbiota-modulating properties.

Sex differences in the association between plasma branched-chain amino acids and risk of ischemic stroke: A nested case-control study from China

OBJECTIVES

The aim of this study was to investigate the prospective associations between plasma branched-chain amino acids (BCAAs) and the risk of ischemic stroke in men and women.

METHODS

We conducted a nested case-control study within a community-based cohort in China. The cohort consisted of 15,926 participants in 2013-2018. A total of 321 ischemic stroke cases were identified during the follow up and individually matched with 321 controls by date of birth (±1 year) and sex. Females accounted for 55.8% (n = 358, 179 cases vs 179 controls) of the study population. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the association between plasma BCAAs and ischemic stroke risk by conditional logistic regression.

RESULTS

Elevated plasma isoleucine was associated with a higher risk of ischemic stroke in women. The OR for the highest compared to the lowest quartile was 2.22 (95% CI: 1.11-4.44, P trend = 0.005) after adjustment for body mass index, education attainment, smoking, hypertension, renal function, menopause and physical activity. A similar association was found for total BCAAs (adjusted OR = 2.03, 95% CI: 1.05-3.95, P trend = 0.04). In contrast, no significant association of plasma BCAAs with ischemic stroke risk was observed in men.

CONCLUSIONS

Plasma isoleucine and total BCAAs were significantly associated with ischemic stroke risk in women, but not in men, highlighting sex differences in BCAAs metabolism and stroke pathogenesis.

The Tryptophan Index Is Associated with Risk of Ischemic Stroke: A Community-Based Nested Case-Control Study

BACKGROUND

The relative availability of the essential amino acid tryptophan in the brain, as indicated by the tryptophan index, which is the ratio of tryptophan to its competing amino acids (CAAs) in circulation, has been related to major depression. However, it remains unknown whether tryptophan availability is involved in the pathogenesis of ischemic stroke.

AIMS

We aimed to investigate the relationship between the tryptophan index and the risk of ischemic stroke.

METHODS

We performed a nested case-control study within a community-based cohort in eastern China over the period 2013 to 2018. The analysis included 321 cases of ischemic stroke and 321 controls matched by sex and date of birth. The plasma levels of tryptophan and CAAs, including tyrosine, valine, phenylalanine, leucine, and isoleucine, were measured by ultra-high-performance liquid chromatography-tandem mass spectrometry. Conditional logistic regression analyses were employed to determine incidence rate ratios (IRRs) and their 95% confidence intervals (CIs).

RESULTS

After adjustment for body mass index, current smoking status, educational attainment, physical activity, family history of stroke, hypertension, diabetes, hyperlipidemia, and estimated glomerular filtration rate, an elevated tryptophan index was significantly associated with a reduced risk of ischemic stroke in a dose-response manner (IRR, 0.76; 95% CI, 0.63-0.93, per standard deviation increment). The plasma tryptophan or CAAs were not separately associated with the risk of ischemic stroke.

CONCLUSIONS

The tryptophan index was inversely associated with the risk of ischemic stroke. Our novel observations suggest that the availability of the essential amino acid tryptophan in the brain is involved in the pathogenesis of ischemic stroke.

Bibliometric analysis of the gut microbiota and stroke from 2002 to 2022

Stroke is the fifth leading cause of death worldwide, and the functional status of the gut plays a key role in patients' prognosis. Recent publications have explored the gut association with stroke, but few articles have been published that specifically address a comprehensive bibliometric analysis of the gut microbiota and its association with stroke. To address this gap, we used bibliometric methods to examine the landscape of research concerning the gut and stroke over approximately two decades, utilizing the Web of Science Core Collection (WoSCC). On November 1, 2022, a search was conducted for English-language articles published between 2002 and 2022, with only including original articles. Visual and statistical analyses were performed using CiteSpace, VOSviewer, and Bibliometrix 4.1.0 Package. After screening relevant articles, the results revealed that the number of articles published in this field has progressively increased during the last two decades. In particular, the total number of publications rapidly increased year by year from 2014. Among them, China ranked first in the world with a total of 227 publications. Authorship analysis highlighted Wang Z as the most prolific author, with 18 publications and an H-index of 14, highlighting significant contributions to this field. Meanwhile, the Southern Medical University of China was identified as the most productive institution. Moreover, analysis of keywords revealed that 'cerebral ischemia', 'intestinal microbiota', 'gut microbiota', and 'trimethylamine N-oxide' were popular topics searched, and research on the relationship between stroke and the gut continues to be a research hotspot. In summary, this study presents an overview of the progress and emerging trends in research on the relationship between stroke and gut health over the past two decades, providing a valuable resource for researchers aiming to understand the current state of the field and identify potential directions for future studies.

Dietary choline intake and health outcomes in U.S. adults: exploring the impact on cardiovascular disease, cancer prevalence, and all-cause mortality

BACKGROUND

Choline, an indispensable nutrient, plays a pivotal role in various physiological processes. The available evidence regarding the nexus between dietary choline intake and health outcomes, encompassing cardiovascular disease (CVD), cancer, and all-cause mortality, is limited and inconclusive. This study aimed to comprehensively explore the relationship between dietary choline intake and the aforementioned health outcomes in adults aged > 20 years in the U.S.

METHODS

This study utilized data from the National Health and Nutrition Examination Survey between 2011 and 2018. Dietary choline intake was evaluated using two 24-h dietary recall interviews. CVD and cancer status were determined through a combination of standardized medical status questionnaires and self-reported physician diagnoses. Mortality data were gathered from publicly available longitudinal Medicare and mortality records. The study utilized survey-weighted logistic and Cox regression analyses to explore the associations between choline consumption and health outcomes. Restricted cubic spline (RCS) analysis was used for dose‒response estimation and for testing for nonlinear associations.

RESULTS

In our study of 14,289 participants (mean age 48.08 years, 47.71% male), compared with those in the lowest quintile (Q1), the adjusted odds ratios (ORs) of CVD risk in the fourth (Q4) and fifth (Q5) quintiles of choline intake were 0.70 (95% CI 0.52, 0.95) and 0.65 (95% CI 0.47, 0.90), respectively (p for trend = 0.017). Each 100 mg increase in choline intake was associated with a 9% reduced risk of CVD. RCS analysis revealed a linear correlation between choline intake and CVD risk. Moderate choline intake (Q3) was associated with a reduced risk of mortality, with an HR of 0.75 (95% CI 0.60-0.94) compared with Q1. RCS analysis demonstrated a significant nonlinear association between choline intake and all-cause mortality (P for nonlinearity = 0.025). The overall cancer prevalence association was nonsignificant, except for colon cancer, where each 100 mg increase in choline intake indicated a 23% reduced risk.

CONCLUSION

Elevated choline intake demonstrates an inverse association with CVD and colon cancer, while moderate consumption exhibits a correlated reduction in mortality. Additional comprehensive investigations are warranted to elucidate the broader health implications of choline.

Trimethylamine N-oxide, β-alanine, tryptophan index, and vitamin B6-related dietary patterns in association with stroke risk

BACKGROUND AND AIMS

The aim of this study was to examine the associations of dietary patterns derived by reduced-rank regression (RRR) model reflecting variation in novel biomarkers (trimethylamine N-oxide, β-alanine, tryptophan index, and vitamin B6) with stroke risk.

METHODS AND RESULTS

We performed analyses based on a community-based cohort study "the Prospective Follow-up Study on Cardiovascular Morbidity and Mortality in China (PFS-CMMC)". Factor loadings were calculated by RRR using 11 food groups collected via a validated food frequency questionnaire and the four response variables based on its nested case-control data (393 cases of stroke vs. 393 matched controls). Dietary pattern scores were derived by applying the factor loadings to the food groups in the entire cohort (n = 15,518). The associations of dietary pattern with the stroke risk were assessed using Cox proportional hazards models. The dietary pattern characterized with higher intakes of red meat and poultry but lower intakes of fresh vegetables, fresh fruits, and fish/seafoods were identified for further analyses. The hazard ratios (HR) for the highest vs. lowest quartile was 1.55 [95 % confidence interval (CI): 1.18-2.03, P trend = 0.001] for total stroke, 2.96 [95 % CI: 1.53-5.71, P trend <0.001] for non-ischemic stroke, after adjustment for sex, age, educational attainment, current smoking, current drinking, body mass index, total energy intake, family history of stroke, hypertension, diabetes, hyperlipidemia, and estimated glomerular filtration rate.

CONCLUSION

Our findings highlight the importance of limited meat intake and increased intakes of fresh vegetables, fruits, and fish/seafoods in the prevention of stroke among Chinese adults.

Plasma levels of urea cycle related amino acids in association with risk of ischemic stroke: Findings from a nested case-control study

OBJECTIVES

The role of urea cycle related amino acids in the development of ischemic stroke (IS) remains unclear. The study aimed to evaluate the association of these amino acids with IS.

MATERIALS AND METHODS

We conducted a case-control study nested within a cohort study in Changshu, Eastern China. A total of 321 cases and 321 controls matched by age and gender were finally included. Plasma levels of ornithine, arginine, spermidine, and proline were measured using ultra-high performance liquid chromatography-tandem mass-spectrometry (UHPLC-MS/MS). Odds ratios (ORs) and their 95 % confidence intervals (CIs) were calculated by conditional logistic regression analyses.

RESULTS

Plasma ornithine was inversely associated with risk of IS [crude OR: 0.62 (95 % CI: 0.40-0.97)]. After adjustment for body mass index, smoking, hypertension, family history of stroke, estimated glomerular filtration rate, and total cholesterol, the corresponding ORs for the highest compared to the lowest quartiles was essentially unchanged [adjusted OR: 0.62 (95 % CI: 0.39-0.99)]. The risk association remained significant after repeating the analyses by excluding the first two years of follow-up. Plasma arginine, spermidine, and proline were not associated with the risk of IS.

CONCLUSION

We observed that higher plasma levels of ornithine were associated with a lower risk of incident IS. Our novel findings suggest a protective role of ornithine in the pathogenesis of IS.

Effect of TMAO on the incidence and prognosis of cerebral infarction: a systematic review and meta-analysis

Objective

This study aimed to evaluate the effect of trimethylamine oxide (TMAO) on the incidence and prognosis of cerebral infarction.

Methods

We searched PubMed, Embase, and Cochrane databases for all clinical studies on the association of TMAO with cerebral infarction incidence and prognosis from inception to April 2023. A systematic review and meta-analysis were conducted using the meta-analysis of observational studies in epidemiology (MOOSE) declaration list. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the study. This study protocol was registered on the PROSPERO database with the ID: CRD42023459661. The extracted data included the OR value of the effect of TMAO on the incidence and prognosis of cerebral infarction, the HR value between TMAO and underlying diseases, the RR value, 95% confidence intervals, and the AUC value of TMAO in the prediction model of cerebral infarction.

Results

Fifteen studies including 40,061 patients were included. All the patients were from China or Germany. The TMAO level was significantly correlated with the Modified Rankin Score (mRS) 3 months after the onset of cerebral infarction (OR, 1.581; 95% CI, 1.259-1.987; p < 0.01). The TMAO level was significantly correlated with the rate of first-time incidence and recurrence of cerebral infarction (OR, 1.208; 95% CI, 1.085-1.344; p < 0.01 and HR, 1.167; 95% CI, 1.076-1.265; p < 0.01, respectively). The TMAO level was also highly correlated with disease severity at onset (National Institutes of Health Stroke Scale, NIHSS >5) (OR, 5.194; 95% CI, 1.206-22.363; p < 0.05), but had no significant correlation with mortality after cerebral infarction (p > 0.05). Correlation analysis of TMAO with underlying diseases in the population indicated that TMAO had a significant correlation with histories of hypertension, diabetes mellitus, coronary artery disease, and cerebral infarction (p < 0.05), but not with hyperlipidemia (p > 0.05). Six risk prediction models of TMAO for cerebral infarction reported in four studies were systematically evaluated; five of them had good predictive value (AUC ≥ 0.7).

Conclusion

TMAO is an independent risk factor affecting the onset, prognosis, and severity of cerebral infarction.

Stroke and Vascular Cognitive Impairment: The Role of Intestinal Microbiota Metabolite TMAO

The gut microbiome interacts with the brain bidirectionally through the microbiome-gutbrain axis, which plays a key role in regulating various nervous system pathophysiological processes. Trimethylamine N-oxide (TMAO) is produced by choline metabolism through intestinal microorganisms, which can cross the blood-brain barrier to act on the central nervous system. Previous studies have shown that elevated plasma TMAO concentrations increase the risk of major adverse cardiovascular events, but there are few studies on TMAO in cerebrovascular disease and vascular cognitive impairment. This review summarized a decade of research on the impact of TMAO on stroke and related cognitive impairment, with particular attention to the effects on vascular cognitive disorders. We demonstrated that TMAO has a marked impact on the occurrence, development, and prognosis of stroke by regulating cholesterol metabolism, foam cell formation, platelet hyperresponsiveness and thrombosis, and promoting inflammation and oxidative stress. TMAO can also influence the cognitive impairment caused by Alzheimer's disease and Parkinson's disease via inducing abnormal aggregation of key proteins, affecting inflammation and thrombosis. However, although clinical studies have confirmed the association between the microbiome-gut-brain axis and vascular cognitive impairment (cerebral small vessel disease and post-stroke cognitive impairment), the molecular mechanism of TMAO has not been clarified, and TMAO precursors seem to play the opposite role in the process of poststroke cognitive impairment. In addition, several studies have also reported the possible neuroprotective effects of TMAO. Existing therapies for these diseases targeted to regulate intestinal flora and its metabolites have shown good efficacy. TMAO is probably a new target for early prediction and treatment of stroke and vascular cognitive impairment.

The association between trimethylamine N-oxide levels and ischemic stroke occurrence: a meta-analysis and Mendelian randomization study

BACKGROUND

Trimethylamine-N-oxide (TMAO), an intestinal microbiota-derived choline metabolite, has been found to be associated with ischemic stroke (IS) in more and more studies. However, the causal role of TMAO on IS occurrence remains perplexing.

METHODS

We comprehensively screened the related clinical studies on PubMed, Web of Science, and Embase. Case-control and cohort studies that reported the TMAO levels of both IS patients and healthy controls were included, and the risk of bias was assessed according to the criteria by the Centre for Evidence-Based Medicine in Oxford, UK. A meta-analysis of the retrieved publications was performed with a random-effect model to analyze the connection between TMAO levels and IS events. Besides, a Mendelian randomization (MR) analysis was performed to study the causal effect of TMAO on IS, with pooled data of TMAO and IS obtained from genome-wide association studies (GWAS). The following methods were used: MR-Egger, weighted median, inverse-variance weighted, simple mode, and weighted mode. The study has been registered in INPLASY (Registration number: INPLASY2023100027).

RESULTS

Eight cohort or case-control studies covering 2444 cases and 1707 controls were identified. The pooled data indicated that the IS patients tended to have higher TMAO levels compared with the controls (mean difference: 1.97 μM; 95% confidence interval [CI]: 0.87, 3.07; P = 0.0005), while distinctive heterogeneity (I2 = 96%, P < 0.00001) was observed. Sub-group analysis revealed that the heterogeneity of the studies might be derived from the studies themselves. However, no causal effect of TMAO on IS was observed (P > 0.05) in the Mendelian randomization analysis of this study.

CONCLUSION

We confirmed that IS patients tend to have higher TMAO levels than healthy individuals, while our findings of MR analysis did not support the causal role of TMAO in IS occurrence. Therefore, more studies are required for a better understanding of the relationship between TMAO levels and IS onset.

The relationship between trimethylamine-N-oxide and the risk of acute ischemic stroke: A dose‒response meta-analysis

BACKGROUND

Although trimethylamine-N-oxide (TMAO) shows a notable correlation with cardiovascular disease, its association with acute ischemic stroke (AIS) remains uncertain and necessitates further investigation.

OBJECTIVE

A meta-analysis was conducted to assess the relationship between trimethylamine-N-oxide and acute ischemic stroke.

METHODS

We conducted a comprehensive search in PubMed, Embase, Cochrane, CNKI, VIP, Wanfang, and CBM, spanning from their inception to 23 September 2023. The search was consistently updated and supplemented by bibliographies of retrieved articles and previous reviews. A total of 20 eligible studies, including 17 case‒controls and 3 cohort studies, were selected, involving 9141 participants (5283 case group, 3858 control group). For the dose‒response analysis, three case-control studies were eligible. We extracted and pooled TMAO mean and standard deviation from observational studies for control and ischemic stroke groups. The effect sizes were combined using the random-effects model. Where possible, dose‒response analysis was performed.

RESULT

Overall, the pooled standardized mean difference (SMD) demonstrated significantly higher concentrations of serum/plasma TMAO in AIS compared to the control group (SMD = 1.27; 95% CI: 0.9, 1.61, P<0.001). Additionally, the dose‒response meta-analysis revealed a 12.1% relative increase in the risk of acute ischemic stroke per 1 μmol/L rise in TMAO concentration (RR = 1.12; 95% CI 1.07-1.17; P<0.05; I2 = 1.6%, P = 0.4484).

CONCLUSION

These findings indicate a potential increased risk of AIS associated with elevated TMAO levels.

Plasma β-Alanine is Positively Associated With Risk of Ischemic Stroke: a Nested Case-Control Study

BACKGROUND

Previous studies suggested that β-alanine as a neurotransmitter could affect the pathogenesis of ischemic damage. However, the association between circulating β-alanine and risk of ischemic stroke (IS) has not been evaluated in populations.

OBJECTIVES

We aimed to examine the association between β-alanine and IS risk in a nested case-control study.

METHODS

We performed a case-control study nested within a prospective community-based cohort (n = 16457; median follow-up time: 5.3 y), which included 321 incident IS cases and 321 controls matched by age and sex. Β-alanine and other metabolites were measured in plasma after overnight fasting by LC-MS/MS. The association of β-alanine with risk of IS was evaluated by conditional logistic regression. BMI, current smoking, educational attainment, physical activity, total energy intake, family history of stroke, hypertension, diabetes, hyperlipidemia, and estimated GFR were adjusted in multivariable models.

RESULTS

There was a significant Spearman partial correlation between β-alanine and 4-pyridoxic acid (ρ = 0.239; P < 0.001). Participants with elevated β-alanine levels were more likely to develop IS with an adjusted OR of 1.26 (95% CI: 1.06-1.51; P = 0.011) (per standard deviation increment). This association remained significant after excluding the first 2 y of follow-up, and after further adjustment for red meat intake, total protein intake, medication use, or vitamin B6 indicators.

CONCLUSIONS

Our novel findings revealed that plasma β-alanine at baseline were positively associated with risk of IS and may function as an early biomarker of IS risk.