The Association of Plasma Trimethylamine N-Oxide with Coronary Atherosclerotic Burden in Patients with Type 2 Diabetes Among a Chinese North Population

Association between plasma trimethylamine N-oxide and coronary heart disease: new insights on sex and age differences

Aim

Elevated plasma trimethylamine N-oxide (TMAO) is related to atherosclerosis. Whether the relationship of TMAO and coronary heart disease (CHD) is influenced by sex or age is uncertain. We aim to explore the sex and age differences in the relationship between plasma TMAO and CHD risk and severity.

Methods

A case-control study was conducted in patients undergoing elective coronary angiography. Matched by sex, age (±2 years), and operation date (±180 days), a total of 429 CHD case-control pairs were included. Plasma TMAO was quantified using liquid chromatography-tandem mass spectrometry. Logistic regression analyses were performed to evaluate the association between plasma TMAO and CHD risk and severity.

Results

The overall median (interquartile range) plasma TMAO level was 0.11 (0.06-0.18) μg/ml. After stratification by sex and age, and adjustment for common CHD risk factors, the association between TMAO and CHD risk was significant in the older (≥65 years) male subgroup [odds ratios (OR) = 1.57, 95% confidence interval (CI): 1.09-2.28, P = 0.016], but not in other sex-age subgroups (all P > 0.05). The relationship of plasma TMAO and CHD risk was modified by age (adjusted P interaction = 0.001) in male individuals. Plasma TMAO was also associated with a higher risk of multi-vessel disease in male patients with CHD (OR = 1.65, 95% CI: 1.18-2.32, P = 0.004), but not in females.

Conclusions

Plasma TMAO is significantly positively associated with the risk and severity of CHD in Chinese men. Age has an interactive effect on the relationship between plasma TMAO and CHD risk in men. Our findings warrant further investigation.

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.

New Modifiable Risk Factors Influencing Coronary Artery Disease Severity

Cardiovascular diseases (CVDs) remain the leading cause of death worldwide with coronary artery disease (CAD) being the first culprit in this group. In terms of CAD, not only its presence but also its severity plays a role in the patient's treatment and prognosis. CAD complexity can be assessed with the indicator named the SYNTAX score (SS). A higher SS is associated with major adverse cardiovascular event (MACE) occurrence in short- and long-term observations. Hence, the risk factors affecting CAD severity based on SS results may help lower the risk among patients with already developed CAD to reduce their impact on coronary atherosclerosis progression. The well-established risk factors of CAD are consistent with those associated with the coronary plaque burden. However, recently, it was shown that new indicators exist, which we present in this paper, that significantly contribute to CAD complexity such as inflammatory parameters, C-reactive protein (CRP), ratios based on blood smear results, and uric acid. Moreover, microbiota alteration, vitamin D deficiency, and obstructive sleep apnea (OSA) also predicted CAD severity. However, sometimes, certain indicators were revealed as significant only in terms of chronic coronary syndromes (CCSs) or specific acute coronary syndromes (ACSs). Importantly, there is a need to apply the interdisciplinary and translational approach to the novel CAD severity risk assessment to maximize the impact of secondary prevention among patients at risk of coronary atherosclerosis progression.

The roles of gut microbiota and its metabolites in diabetic nephropathy

Diabetic nephropathy (DN) is a severe microvascular complication of diabetes, which increases the risk of renal failure and causes a high global disease burden. Due to the lack of sustainable treatment, DN has become the primary cause of end-stage renal disease worldwide. Gut microbiota and its metabolites exert critical regulatory functions in maintaining host health and are associated with many pathogenesis of aging-related chronic diseases. Currently, the theory gut-kidney axis has opened a novel angle to understand the relationship between gut microbiota and multiple kidney diseases. In recent years, accumulating evidence has revealed that the gut microbiota and their metabolites play an essential role in the pathophysiologic processes of DN through the gut-kidney axis. In this review, we summarize the current investigations of gut microbiota and microbial metabolites involvement in the progression of DN, and further discuss the potential gut microbiota-targeted therapeutic approaches for DN.

Association between Plasma Trimethylamine N-Oxide Levels and Type 2 Diabetes: A Case Control Study

Animal and human studies have reported conflicting results on the relationship between circulating trimethylamine N-oxide (TMAO) levels and risk of Type 2 diabetes (T2D). This study aimed to compare plasma TMAO levels in people with or without T2D and explore the association of TMAO and T2D. A prospective case-control study of 297 participants, 164 healthy controls and 133 patients with T2D, was conducted. TMAO levels were quantified by UPLC-MS/MS. Comorbidities, dietary patterns, physical activity, and blood biomarkers were assessed. Median (IQR) plasma TMAO levels were significantly higher in diabetes cases (4.95 (2.84−8.35) µmol/L) compared to healthy controls (3.07 (2.05−4.82) µmol/L) (p < 0.001). The association between TMAO and T2D was significant in the non-adjusted Model 1 (p < 0.001) and after adjusting for confounders of diabetes including age, BMI, and level of education in Model 2 (p = 0.04). When the association was further adjusted for physical activity and diet in Model 3, plasma TMAO levels at only the highest quartile (>6.40 µmol/L) were associated with the risk of diabetes (OR = 3.36, 95% CI [1.26, 9.04], p = 0.02). The results presented suggest an association between plasma TMAO levels and T2D. A significant correlation was found between red meat consumption and increased levels of TMAO in T2D patients. A longitudinal study is warranted to further evaluate the correlation between TMAO and T2D.