The Role of Bile Acids in Cardiovascular Diseases: from Mechanisms to Clinical Implications

The gut-heart axis: unveiling the roles of gut microbiota in cardiovascular diseases

The gut microbiome refers to the collective genomes of the approximately 1,000-1,150 microbial species found in the human gut, called the gut microbiota. Changing the gut microbiota composition has been shown to affect cardiovascular health significantly. Numerous studies have demonstrated the part that gut microbiota and its metabolites play in the development and course of several illnesses, including colon cancer, heart failure, stroke, hypertension, and inflammatory bowel disease. With cardiovascular diseases responsible for more than 31% of all fatalities globally, conditions like hypertension, atherosclerosis, and heart failure are serious global health issues. Developing preventive measures to fight cardiovascular diseases requires understanding how the gut microbiota interacts with the cardiovascular system. Understanding the distinctive gut microbiota linked to cardiovascular diseases has been made possible by microbial sequencing analysis. The gut microbiota and cardiovascular diseases are closely related, and more profound knowledge of this association may result in treatment strategies and broad guidelines for enhancing cardiovascular health through gut microbiome modification. This review summarizes the role of gut microbiota in cardiovascular diseases, highlighting their influence on disease progression and potential therapeutic implications.

The gut microbiota-inflammation-HFpEF axis: deciphering the role of gut microbiota dysregulation in the pathogenesis and management of HFpEF

Heart failure with preserved left ventricular ejection fraction (HFpEF) is a disease that affects multiple organs throughout the body, accounting for over 50% of heart failure cases. HFpEF has a significant impact on individuals' life expectancy and quality of life, but the exact pathogenesis remains unclear. Emerging evidence implicates low-grade systemic inflammation as a crucial role in the onset and progression of HFpEF. Gut microbiota dysregulation and associated metabolites alteration, including short-chain fatty acids, trimethylamine N-oxides, amino acids, and bile acids can exacerbate chronic systemic inflammatory responses and potentially contribute to HFpEF. In light of these findings, we propose the hypothesis of a "gut microbiota-inflammation-HFpEF axis", positing that the interplay within this axis could be a crucial factor in the development and progression of HFpEF. This review focuses on the role of gut microbiota dysregulation-induced inflammation in HFpEF's etiology. It explores the potential mechanisms linking dysregulation of the gut microbiota to cardiac dysfunction and evaluates the therapeutic potential of restoring gut microbiota balance in mitigating HFpEF severity. The objective is to offer novel insights and strategies for the management of HFpEF.

The Diagnostic Value of Bile Acids and Amino Acids in Differentiating Acute Coronary Syndromes

Purpose

Acute coronary syndrome (ACS), comprising unstable angina and acute myocardial infarction, is the most dangerous and fatal form of coronary heart disease. This study evaluates serum bile acids (BAs) and amino acids (AAs) as potential predictors of AMI in UA patients.

Patients and Methods

A total of 72 Non-Coronary Artery Disease (NCAD) patients, 157 UA patients, and 79 AMI patients were analyzed. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) measured 15 bile acids and 19 amino acids. The data was split into training and validation sets (7:3). Univariate and multivariate analyses were performed. Diagnostic value and clinical benefits were assessed using receiver operating characteristic (ROC) curves, decision curve analysis, and metrics such as the area under the curve (AUC), integrated discrimination improvement (IDI), and net reclassification improvement (NRI).

Results

Orthogonal partial least squares discriminant analysis (OPLS-DA) of serum BAs and AAs effectively differentiated NCAD, UA, and AMI groups. The differences in serum BA and AA profiles between UA and AMI patients were primarily driven by four metabolites: deoxycholic acid (DCA), histidine (His), lysine (Lys), and phenylalanine (Phe). Together, they had an AUC of 0.830 (0.768 in the validation cohort) for predicting AMI in UA patients. After adjusting for multiple confounding factors, DCA, His, Lys, and Phe were independent predictors distinguishing UA from AMI. The results of AUC, IDI, and NRI showed that adding these four biomarkers to a model with clinical variables significantly improved predictive value, which was confirmed in the validation cohort.

Conclusion

These findings highlight the association of DCA, His, Lys, and Phe with AMI, suggesting their potential role in AMI pathogenesis.

The association of serum total bile acids and deep venous thrombosis

BACKGROUND AND AIM

Bile acid metabolism plays a crucial role in maintaining the delicate balance between coagulation and anticoagulation processes. However, there is a paucity of research exploring the relationship between serum total bile acids (TBA) levels and the risk of deep venous thrombosis (DVT) in Chinese individuals. The primary objective of this study is to investigate the association between TBA levels and DVT occurrence in this population.

METHODS AND RESULTS

A cross-sectional study was conducted involving 4522 patients with suspected DVT, recruited from June 2018 to October 2023, at the First Affiliated Hospital of Xi'an Jiaotong University. After rigorous screening, 3165 patients were included in the final analysis. Participants were categorized into three TBA level groups: low-level (TBA < 2.3 umol/L), moderate-level (2.3 ≤ TBA < 4.3 umol/L), and high-level (TBA ≥ 4.3 umol/L). Logistic regression analysis was utilized to assess the relationship between TBA levels and DVT risk, adjusting for potential confounders. The median age of the study population was 63 years, with a median TBA level of 3.2 (1.9-5.3) umol/L. The findings revealed that, compared to the low-level TBA group, the moderate and high-level TBA groups had significantly higher odds ratios (ORs) for DVT, with ORs of 1.47 (95% CI: 1.21 to 1.78, P < 0.001) and 1.91 (95% CI: 1.58 to 2.32, P < 0.001), respectively. Interestingly, higher TBA levels were also associated with reduced odds of bleeding risk, with ORs of 0.81 (95% CI: 0.63 to 1.03, P < 0.001) and 0.64 (95% CI: 0.5 to 0.81, P < 0.001), respectively.

CONCLUSIONS

Our study provides evidence that serum TBA levels may serve as a risk factor for DVT in Chinese individuals, with higher levels conferring an increased risk. Additionally, unexpectedly, higher TBA levels were found to be associated with a reduced risk of bleeding complications. These findings have significant implications for understanding the complex interplay between bile acid metabolism and deep venous thrombosis, and warrant further investigation.

Microbiome-metabolome analysis insight into the effects of high-salt diet on hemorheological functions in SD rats

The present study examined the effect of two dietary regimens with elevated salt concentrations (4% and 8% salt) on hemorheological functions of SD rats, and explored the underlying mechanisms mainly through microbiome-metabolome analysis. An 8% HSD substantially altered the hemorheological parameters, and compromised intestinal barrier integrity and reduced the short-chain fatty acid levels. The microbiome-metabolome analysis revealed that 49 genus-specific microorganisms and 156 metabolites showed a consistent trend after exposure to both 4% and 8% HSDs. Pathway analysis identified significant alterations in key metabolites within bile acid and arachidonic acid metabolism pathways. A two-sample Mendelian randomization (MR) analysis verified the link between high dietary salt intake and hemorheology. It also suggested that some key microbes and metabolites (such as Ruminococcaceae_UCG-005, Lachnospiraceae_NK4A136, Ruminiclostridium_6, and Ruminococcaceae_UCG-010, TXB-2, 11,12-diHETrE, glycochenodeoxycholate) may involve in abnormalities in blood rheology caused by high salt intake. Collectively, our findings underscored the adverse effects of high dietary salt on hemorheological functions and provide new insight into the underlying mechanism based on microbiome-metabolome analysis.

Plasma endocannabinoidome and fecal microbiota interplay in people with HIV and subclinical coronary artery disease: Results from the Canadian HIV and Aging Cohort Study

Chronic HIV infection is associated with accelerated coronary artery disease (CAD) due to chronic inflammation. The expanded endocannabinoid system (eCBome) and gut microbiota modulate each other and are key regulators of cardiovascular functions and inflammation. We herein investigated the interplay between plasma eCBome mediators and gut microbiota in people with HIV (PWH) and/or subclinical CAD versus HIV-uninfected individuals. CAD was determined by coronary computed tomography (CT) angiography performed on all participants. Plasma eCBome mediator and fecal microbiota composition were assessed by tandem mass spectrometry and 16S rDNA sequencing, respectively. HIV infection was associated with perturbed plasma eCBome mediators characterized by an inverse relationship between anandamide and N-acyl-ethanolamines (NAEs) versus 2-AG and 2-monoacylglycerols (MAGs). Plasma triglyceride levels were positively associated with MAGs. Several fecal bacterial taxa were altered in HIV-CAD+ versus controls and correlated with plasma eCBome mediators. CAD-associated taxonomic alterations in fecal bacterial taxa were not found in PWH.

Exposure of Ldlr-/- Mice to a PFAS Mixture and Outcomes Related to Circulating Lipids, Bile Acid Excretion, and the Intestinal Transporter ASBT

BACKGROUND

Previous epidemiological studies have repeatedly found per- and polyfluoroalkyl substances (PFAS) exposure associated with higher circulating cholesterol, one of the greatest risk factors for development of coronary artery disease. The main route of cholesterol catabolism is through its conversion to bile acids, which circulate between the liver and ileum via enterohepatic circulation. Patients with coronary artery disease have decreased bile acid excretion, indicating that PFAS-induced impacts on enterohepatic circulation may play a critical role in cardiovascular risk.

OBJECTIVES

Using a mouse model with high levels of low-density and very low-density lipoprotein (LDL and VLDL, respectively) cholesterol and aortic lesion development similar to humans, the present study investigated mechanisms linking exposure to a PFAS mixture with increased cholesterol.

METHODS

Male and female L d l r - / - mice were fed an atherogenic diet (Clinton/Cybulsky low fat, 0.15% cholesterol) and exposed to a mixture of 5 PFAS representing legacy, replacement, and emerging subtypes (i.e., PFOA, PFOS, PFHxS, PFNA, GenX), each at a concentration of 2 mg / L , for 7 wk. Blood was collected longitudinally for cholesterol measurements, and mass spectrometry was used to measure circulating and fecal bile acids. Transcriptomic analysis of ileal samples was performed via RNA sequencing.

RESULTS

After 7 wk of PFAS exposure, average circulating PFAS levels were measured at 21.6, 20.1, 31.2, 23.5, and 1.5 μ g / mL in PFAS-exposed females and 12.9, 9.7, 23, 14.3, and 1.7 μ g / mL in PFAS-exposed males for PFOA, PFOS, PFHxS, PFNA, and GenX, respectively. Total circulating cholesterol levels were higher in PFAS-exposed mice after 7 wk (352 mg / dL vs. 415 mg / dL in female mice and 392 mg / dL vs. 488 mg / dL in male mice exposed to vehicle or PFAS, respectively). Total circulating bile acid levels were higher in PFAS-exposed mice (2,978  pg / μ L vs. 8,496  pg / μ L in female mice and 1,960  pg / μ L vs. 4,452  pg / μ L in male mice exposed to vehicle or PFAS, respectively). In addition, total fecal bile acid levels were lower in PFAS-exposed mice (1,797  ng / mg vs. 682  ng / mg in females and 1,622  ng / mg vs. 670  ng / mg in males exposed to vehicle or PFAS, respectively). In the ileum, expression levels of the apical sodium-dependent bile acid transporter (ASBT) were higher in PFAS-exposed mice.

DISCUSSION

Mice exposed to a PFAS mixture displayed higher circulating cholesterol and bile acids perhaps due to impacts on enterohepatic circulation. This study implicates PFAS-mediated effects at the site of the ileum as a possible critical mediator of increased cardiovascular risk following PFAS exposure. https://doi.org/10.1289/EHP14339.

Evaluation of alanine aminotransferase/aspartate aminotransferase ratio and high-density lipoprotein for predicting neonatal adverse outcomes associated with intrahepatic cholestasis of pregnancy

Background

To determine the association between lipid metabolism and intrahepatic cholestasis of pregnancy (ICP), and explore the value of maternal alanine aminotransferase/aspartate aminotransferase (ALT/AST) and high-density lipoprotein (HDL) in predicting adverse neonatal outcomes in women with ICP.

Methods

A total of 147 pregnant women with ICP admitted to The Fourth Hospital of Shijiazhuang and 120 normal pregnant women in the same period were selected in this study. The Mann-Whitney U test and Chi-square tests were used to compare the differences in clinical data. Multivariate logistic regression was used to analyze the relationship between ALT/AST and the occurrence of adverse pregnancy outcomes in patients with ICP. The combined predictive value of ALT/AST and HDL was determined by receiver operating characteristic (ROC) curve analysis.

Results

Among 147 women with ICP, 122 women had total bile acid (TBA) levels of 10-39.9 µmol/L, and 25 had TBA ≥ 40 µmol/L. There was significantly lower gestational age in patients with severe ICP than in those with mild and control groups (all p < 0.05), and the weight of newborns in the maternal ICP group was significantly lower than in the control group (p < 0.05). Increasing TBA levels was associated with higher AST, ALT, ALT/AST, and lower HDL level (all p < 0.05). Meanwhile, higher levels of ALT/AST was positively associated with neonatal hyperbilirubinemia [adjusted odds ratio (AOR) = 4.019, 95% CI [1.757-9.194, p = 0.001] and cardiac injury [AOR = 3.500, 95% CI [1.535-7.987], p = 0.003]. HDL was a significant protective factor for neonatal hyperbilirubinemia and cardiac injury [AOR = 0.315, 95% CI [0.126-0.788], p = 0.014; AOR = 0.134 (0.039-0.461), p = 0.001]. The area under the ROC curve (AUC) for prediction of neonatal hyperbilirubinemia by ALT/AST combined with HDL was 0.668 [95% CI [56.3-77.3%], p = 0.002], and the sensitivity and specificity were 47.1% and 84.0%, respectively. To predict neonatal cardiac injury, the AUC value was 0.668 [95% CI [56.4-77.1%], p = 0.002], with sensitivity and specificity were 41.2% and 87.1%, respectively.

Conclusions

The levels of higher ALT/AST and lower HDL were significantly associated with the risk of ICP-related adverse neonatal outcomes. Moreover, ALT/AST combined with HDL has moderate clinical value in predicting the adverse outcomes of neonatal hyperbilirubinemia and cardiac injury.

Relationships between Habitual Polyphenol Consumption and Gut Microbiota in the INCLD Health Cohort

While polyphenol consumption is often associated with an increased abundance of beneficial microbes and decreased opportunistic pathogens, these relationships are not completely described for polyphenols consumed via habitual diet, including culinary herb and spice consumption. This analysis of the International Cohort on Lifestyle Determinants of Health (INCLD Health) cohort uses a dietary questionnaire and 16s microbiome data to examine relationships between habitual polyphenol consumption and gut microbiota in healthy adults (n = 96). In this exploratory analysis, microbial taxa, but not diversity measures, differed by levels of dietary polyphenol consumption. Taxa identified as exploratory biomarkers of daily polyphenol consumption (mg/day) included Lactobacillus, Bacteroides, Enterococcus, Eubacterium ventriosum group, Ruminococcus torques group, and Sutterella. Taxa identified as exploratory biomarkers of the frequency of polyphenol-weighted herb and spice use included Lachnospiraceae UCG-001, Lachnospiraceae UCG-004, Methanobrevibacter, Lachnoclostridium, and Lachnotalea. Several of the differentiating taxa carry out activities important for human health, although out of these taxa, those with previously described pro-inflammatory qualities in certain contexts displayed inverse relationships with polyphenol consumption. Our results suggest that higher quantities of habitual polyphenol consumption may support an intestinal environment where opportunistic and pro-inflammatory bacteria are represented in a lower relative abundance compared to those with less potentially virulent qualities.