The potential links between human gut microbiota and cardiovascular health and disease - is there a gut-cardiovascular axis?

Antibiotic-induced gut dysbiosis: unraveling the gut-heart axis and its impact on cardiovascular health

Cardiovascular diseases (CVDs) remain the major cause of morbidity and mortality amongst people of all ages across the world. Research suggests that the initiation and progression of CVDs are associated with antibiotic-induced gut dysbiosis. Antibiotics are primarily intended to be used to treat bacterial infections, which can alter gut microbiota (GM) composition, by lowering the abundance of beneficial bacteria, like Firmicutes, Bacteroidetes, and increasing the profusion of Enterobacteriaceae, leading to harm on gut health. Additionally, it reduces short-chain fatty acids (SCFAs) and bile acid metabolism, increases trimethylamine N-oxide (TMAO) production, intestinal permeability allowing lipopolysaccharide (LPS) and TMAO into systemic circulation. SCFAs play a key role in lipid metabolism, inflammation, and strengthening of the intestinal barrier, and participate in CVDs through FFAR2 and FFAR3 receptors, whereas dysbiosis reduces SCFAs levels and worsens these effects. TMAO enhances oxidative stress, inflammation, endothelial dysfunction, and cholesterol dysregulation, thus worsening CVDs. Furthermore, LPS develops systemic inflammation, insulin resistance, and endothelial dysfunction by activating the NF-κB pathway. Dysbiosis also affects bile acid synthesis, disrupting lipid and glucose metabolism, further participating in the progression of CVDs. This article aims to explore the role of gut dysbiosis in various CVDs, including congenital heart disease, hypertension, valvular heart disease, coronary heart disease, and heart failure. Furthermore, this article aims to bridge the knowledge gap regarding the gut-heart axis by exploring how antibiotics alter the gut microbiota homeostasis, further contributing to the development of CVDs and therapeutic interventions that reduce cardiovascular risks and restore the gut microbiota homeostasis.

Indoleacetylglutamine Pathway Is a Potential Biomarker for Cardiovascular Diseases

Cardiovascular diseases (CVDs) remain a leading cause of global morbidity and mortality. Metabolomics allows for the identification of important biomarkers for CVDs, essential for early detection and risk assessment. This cross-sectional study aimed to identify novel metabolic biomarkers associated with CVDs using non-targeted metabolomics. We compared the metabolic profiles of 112 patients with confirmed CVDs diagnosis and 112 gender- and age-matched healthy controls from the Qatar Biobank database. Orthogonal partial least square discriminate analysis and linear models were used to analyze differences in the level of metabolites between the two groups. We report here a significant association between the indoleacetylglutamine pathway and cardiovascular diseases, expanding the repertoire of gut microbiota metabolites linked to CVDs. Our findings suggest that alterations in gut microbiota metabolism, potentially resulting in increased production of indoleacetate, indoleacetylglutamine, and related compounds at the expense of the cardioprotective indolepropionate, may contribute to this association. Our findings may pave the way for novel approaches in CVD risk assessment and potential therapeutic interventions targeting the gut-heart axis.

Oxygenation and intestinal perfusion and its association with perturbations of the early life gut microbiota composition of children with congenital heart disease

Background

Early life gut microbiota is known to shape the immune system and has a crucial role in immune homeostasis. Only little is known about composition and dynamics of the intestinal microbiota in infants with congenital heart disease (CHD) and potential influencing factors.

Methods

We evaluated the intestinal microbial composition of neonates with CHD (n = 13) compared to healthy controls (HC, n = 30). Fecal samples were analyzed by shotgun metagenomics. Different approaches of statistical modeling were applied to assess the impact of influencing factors on variation in species composition. Unsupervised hierarchical clustering of the microbial composition of neonates with CHD was used to detect associations of distinct clusters with intestinal tissue oxygenation and perfusion parameters, obtained by the "oxygen to see" (O2C) method.

Results

Overall, neonates with CHD showed an intestinal core microbiota dominated by the genera Enterococcus (27%) and Staphylococcus (20%). Furthermore, a lower abundance of the genera Bacteroides (8% vs. 14%), Parabacteroides (1% vs. 3%), Bifidobacterium (4% vs. 12%), and Escherichia (8% vs. 23%) was observed in CHD compared to HCs. CHD patients that were born by vaginal delivery showed a lower fraction of the genera Bacteroides (15% vs. 21%) and Bifidobacterium (7% vs. 22%) compared to HCs and in those born by cesarean section, these genera were not found at all. In infants with CHD, we found a significant impact of oxygen saturation (SpO2) on relative abundances of the intestinal core microbiota by multivariate analysis of variance (F[8,2] = 24.9, p = 0.04). Statistical modeling suggested a large proportional shift from a microbiota dominated by the genus Streptococcus (50%) in conditions with low SpO2 towards the genus Enterococcus (61%) in conditions with high SpO2. We identified three distinct compositional microbial clusters, corresponding neonates differed significantly in intestinal blood flow and global gut perfusion.

Conclusion

Early life differences in gut microbiota of CHD neonates versus HCs are possibly linked to oxygen levels. Delivery method may affect microbiota stability. However, further studies are needed to assess the effect of potential interventions including probiotics or fecal transplants on early life microbiota perturbations in neonates with CHD.

The gut microbiota and its role in the development of cardiovascular disease

INTRODUCTION

The pathophysiology of cardiovascular diseases encompasses a complex interplay of genetic and environmental risk factors. Even if traditional risk factors are treated to target, there remains a residual risk.

AREAS COVERED

This manuscript reviews the potential role of gut microbiota in the development of cardiovascular disease, and as potential target. A systematic search was conducted until 30 October 2024 on PubMed (MEDLINE), using the MeSH terms [Gut microbiota] + [Dysbiosis] + [Cardiovascular] + [TMAO] + [bile acids] + [short-chain fatty acids].

EXPERT OPINION

The term dysbiosis implies changes in equilibrium, with modifications in the composition and functionality of microbiota and a series of additional factors: reduced diversity and uniformity of microorganisms; reduced short-chain fatty acid-producing bacteria; increased gut permeability; release of metabolites, such as trimethylamine N-oxide, betaine, phenylalanine, tryptophan-kynurenine, phenylacetylglutamine, and lipopolysaccharides; and reduced secondary bile acid excretion, leading to inflammation, oxidative stress, and endothelial dysfunction and facilitating the onset of pathological conditions, including obesity, hypertension, diabetes, atherosclerosis, and heart failure. Attempts to restore gut microbiota balance through different interventions, mainly changes in diet, have been shown to positively affect individual components and metabolites and reduce the risk of cardiovascular disease. In addition, probiotics and prebiotics are potentially useful. Fecal microbiota transplantation is a promising therapy.

Intestinal Insights: The Gut Microbiome's Role in Atherosclerotic Disease: A Narrative Review

Recent advances have highlighted the gut microbiota as a significant contributor to the development and progression of atherosclerosis, which is an inflammatory cardiovascular disease (CVD) characterized by plaque buildup within arterial walls. The gut microbiota, consisting of a diverse collection of microorganisms, impacts the host's metabolism, immune responses, and lipid processing, all of which contribute to atherosclerosis. This review explores the complex mechanisms through which gut dysbiosis promotes atherogenesis. We emphasize the potential of integrating microbiota modulation with traditional cardiovascular care, offering a holistic approach to managing atherosclerosis. Important pathways involve the translocation of inflammatory microbial components, modulation of lipid metabolism through metabolites such as trimethylamine-N-oxide (TMAO), and the production of short-chain fatty acids (SCFAs) that influence vascular health. Studies reveal distinct microbial profiles in atherosclerosis patients, with increased pathogenic bacteria (Megamonas, Veillonella, Streptococcus) and reduced anti-inflammatory genera (Bifidobacterium, Roseburia), highlighting the potential of these profiles as biomarkers and therapeutic targets. Probiotics are live microorganisms that have health benefits on the host. Prebiotics are non-digestible dietary fibers that stimulate the growth and activity of beneficial gut bacteria. Interventions targeting microbiota, such as probiotics, prebiotics, dietary modifications, and faecal microbiota transplantation (FMT), present effective approaches for restoring microbial equilibrium and justifying cardiovascular risk. Future research should focus on longitudinal, multi-omics studies to clarify causal links and refine therapeutic applications.