Gut Microbiota and Coronary Artery Disease: Current Therapeutic Perspectives

Synbiotics of encapsulated Limosilactobacillus fermentum K73 promotes in vitro favorable gut microbiota shifts and enhances short-chain fatty acid production in fecal samples of children with autism spectrum disorder

Modulation of the gut microbiota has emerged as a promising approach for addressing the gastrointestinal and neurodevelopmental symptoms associated with autism spectrum disorder (ASD). Consequently, this study aimed to evaluate the impact of four formulated synbiotics comprising Limoscilactobacillus fermentum K73, high-oleic palm oil and whey, on the gut microbiota composition of Colombian children with and without ASD. These components were encapsulated through high-shear emulsification and spray drying. The four synbiotics and their individual components were subjected to in vitro digestion and fermentation using samples of Colombian children gut microbiota. Short-chain fatty acids (SCFAs), including lactic, acetic, propionic, and butyric acids, were quantified using HPLC-DAD, while serotonin was determined by an ELISA kit after in vitro fermentations. Changes in microbial structure were assessed by the sequencing of the 16S rRNA gene via next-generation sequencing (NGS). The results revealed a decrease in the abundance of genera like Bacteroides and Dorea in ASD-associated samples after the treatment with the synbiotics. Conversely, an increase in the relative abundance of probiotic-related genera, including Lactobacillus, Streptococcus, and Anaerostipes, was observed. Furthermore, the analysis of SCFAs and serotonin indicated that the synbiotic intervention resulted in an elevated butyric acid and microbial serotonin synthesis, alongside a decrease in propionic acid, which is changes considered beneficial in the context of ASD. This evidence suggests that synbiotics of L. fermentum K73 could represent a promising live biotherapeutic strategy for modulating the gut microbiota of children with ASD.

Oxidative Stress, Gut Microbiota, and Extracellular Vesicles: Interconnected Pathways and Therapeutic Potentials

Oxidative stress (OS) and gut microbiota are crucial factors influencing human health, each playing a significant role in the development and progression of chronic diseases. This review provides a comprehensive analysis of the complex interplay between these two factors, focusing on how an imbalance between reactive oxygen species (ROS) and antioxidants leads to OS, disrupting cellular homeostasis and contributing to a range of conditions, including metabolic disorders, cardiovascular diseases, neurological diseases, and cancer. The gut microbiota, a diverse community of microorganisms residing in the gastrointestinal tract, is essential for regulating immune responses, metabolic pathways, and overall health. Dysbiosis, an imbalance in the gut microbiota composition, is closely associated with chronic inflammation, metabolic dysfunction, and various diseases. This review highlights how the gut microbiota influences and is influenced by OS, complicating the pathophysiology of many conditions. Furthermore, emerging evidence has identified extracellular vesicles (EVs) as critical facilitators of cellular crosstalk between the OS and gut microbiota. EVs also play a crucial role in signaling between the gut microbiota and host tissues, modulating immune responses, inflammation, and metabolic processes. The signaling function of EVs holds promise for the development of targeted therapies aimed at restoring microbial balance and mitigating OS. Personalized therapeutic approaches, including probiotics, antioxidants, and fecal microbiota transplantation-based strategies, can be used to address OS-related diseases and improve health outcomes. Nonetheless, further research is needed to study the molecular mechanisms underlying these interactions and the potential of innovative interventions to offer novel strategies for managing OS-related diseases and enhancing overall human health.

Mucosal-associated invariant T cells correlate with myocardial ischaemia and remodelling in coronary artery disease

Objectives

Myocardial ischaemia and remodelling are major contributors to the progression and mortality of coronary artery disease (CAD). Previous studies have shown immune cell alterations in CAD patients, but their characteristics and associations with myocardial ischaemia and remodelling remain unclear.

Methods

We compared immune cell changes among patients without CAD, those with CAD and those with CAD and heart failure (HF).

Results

We found a progressive reduction in circulating mucosal-associated invariant T (MAIT) cells across the three patient groups. MAIT cells exhibited increased expression of activation markers (CD69 and PD-1) and cytotoxic molecules (such as granzyme B). The features of MAIT cells were correlated positively with worsening clinical indicators of myocardial ischaemia and remodelling, including the Gensini score, cTnI, NT-proBNP, LVEF and E/e'. Additionally, the reduction, activation and cytotoxicity of MAIT cells were associated with indicators of myocardial fibrosis (sST2, Gal-3, PICP and PIIINP), a central pathological mechanism of myocardial remodelling. Finally, we preliminarily explored potential triggers for MAIT cell abnormalities in CAD patients and found that impaired intestinal barrier function and increased circulating bacterial antigens may contribute to these changes.

Conclusions

During CAD progression, we observed a decrease in circulating MAIT cells. Enhanced activation and cytotoxicity of MAIT cells are associated with myocardial ischaemia and remodelling in CAD patients with heart failure, potentially triggered by gut microbial leakage. Our findings suggest a novel strategy for monitoring and intervention in disease progression.

Utilizing Lactic Acid Bacteria to Improve Hyperlipidemia: A Comprehensive Analysis from Gut Microbiota to Metabolic Pathways

Hyperlipidemia poses significant risks for cardiovascular diseases, with emerging evidence underscoring the critical role of gut microbiota in metabolic regulation. This study explores Lactobacillus casei CAAS36, a probiotic strain with promising cholesterol-lowering capabilities, assessing its impact on hyperlipidemic hamsters. Utilizing 1H NMR-based metabolomics and 16S rRNA gene sequencing, we observed that L. casei CAAS36 treatment not only altered metabolic pathways but also reshaped gut microbiota composition. Notably, the treatment restored the balance between Firmicutes and Bacteroidetes and significantly increased the abundance of propionate-producing Muribaculaceae. Metabolically, L. casei CAAS36 administration led to the normalization of key lipid markers, including reductions in total cholesterol, LDL-C, and triglycerides (29.9%, 29.4% and 32.6%), while enhancing the protective HDL-C levels. These effects were accompanied by significant increases in beneficial metabolites such as propionate and succinate, which are known for their roles in preventing metabolic disorders. These findings highlight the dual regulatory effects of L. casei CAAS36 on the metabolic profile and gut microbiota, suggesting a substantial potential for this probiotic in the management of hyperlipidemia and possibly other metabolic diseases. Future applications may include its use as a natural therapeutic agent in clinical settings, aiming to reduce reliance on conventional pharmaceuticals and their associated side effects.

Gut microbiota changes associated with frailty in older adults: A systematic review of observational studies

BACKGROUND

Frailty is a complex aging-related syndrome characterized by a cumulative loss of physiological reserve and increased vulnerability to adverse clinical outcomes, including falls, disability, incapacity and death. While an increasing number of studies suggest that the gut microbiota may play a key role in the pathophysiology of frailty, direct evaluation of the association between gut microbiome alterations and frailty in older adults remains limited.

AIM

To gain insight into gut dysbiosis in frail older adults.

METHODS

Seven electronic databases (China National Knowledge Infrastructure, VIP, SinoMed, Wanfang, PubMed, Web of Science and EMBASE) were searched for articles published before October 31, 2023 to identify observational studies that compared the microbiomes of older adults with and without frailty. The diversity and composition of the gut microbiota were the main outcomes used to analyze the associations of changes in the gut microbiota with frailty in older adults. The quality of the included studies was assessed via the Newcastle-Ottawa Scale and the Agency for Healthcare Research and Quality.

RESULTS

Eleven observational studies with 912 older adults were included in this review. Consistent results revealed a significant difference in the gut microbiota composition between frail and non-frail older adults, with a significant decrease in α diversity and a significant increase in β diversity in frail older adults. The pooled results revealed that at the phylum level, four microbiota (Actinobacteria, Proteobacteria, Verrucomicrobia and Synergistetes) were significantly enriched, and two microbiota (Firmicutes and Fusobacteria) were significantly depleted in frail older adults. At the family level, the results consistently revealed that the abundances of 6 families, most of which belong to the Actinobacteria or Proteobacteria phylum, were greater in frail than in non-frail older adults. At the genus or species level, consistent results from more than two studies revealed that the abundances of the genera Prevotella, Faecalibacterium, and Roseburia were significantly lower in frail older adults; individual studies revealed that the abundances of some genera or species (e.g., Megamonas, Blautia, and Megasphaera) were significantly lower, whereas those of other genera or species (e.g., Bifidobacterium, Oscillospira, Ruminococcus and Pyramidobacter) were significantly greater in frail older adults.

CONCLUSION

This systematic review suggests that changes in the gut microbiota are associated with frailty in older adults, which is commonly reflected by a reduction in beneficial species and an increase in pathogenic species. However, further studies are needed to confirm these findings.

Revisiting the Role of Carnitine in Heart Disease Through the Lens of the Gut Microbiota

L-Carnitine, sourced from red meat, dairy, and endogenous synthesis, plays a vital role in fatty acid metabolism and energy production. While beneficial for cardiovascular, muscular, and neural health, its interaction with the gut microbiota and conversion into trimethylamine (TMA) and trimethylamine N-oxide (TMAO) raise concerns about heart health. TMAO, produced through the gut-microbial metabolism of L-carnitine and subsequent liver oxidation, is associated with cardiovascular risks, including atherosclerosis, heart attacks, and stroke. It contributes to cholesterol deposition, vascular dysfunction, and platelet aggregation. Omnivorous diets, rich in L-carnitine, are associated with higher TMAO levels compared to plant-based diets, which are linked to lower cardiovascular disease risks. Dietary interventions, such as increasing fiber, polyphenols, and probiotics, can modulate the gut microbiota to reduce TMAO production. These strategies seek to balance L-carnitine's benefits with its potential risks related to TMAO production. Future research should focus on personalized approaches to optimize L-carnitine use while mitigating its cardiovascular impacts, exploring microbial modulation and dietary strategies to minimize the TMAO levels and associated risks.

Intestinal fatty acid binding protein is associated with coronary artery disease in long-term type 1 diabetes-the Dialong study

BACKGROUND

Individuals with type 1 diabetes are at increased risk of accelerated atherosclerosis, causing coronary artery disease (CAD). The underlying mechanisms remain unclear, but new theories proposed are damage of gut mucosa causing leakage and translocation of gut microbiota products into the circulation, leading to inflammatory responses and atherosclerosis. We therefore aimed to study the associations between gut related inflammatory biomarkers and coronary atherosclerosis in individuals with long-term type 1 diabetes.

METHODS

In this cross-sectional, controlled study of 102 participants with type 1 diabetes and 63 control subjects, we measured circulating levels of intestinal fatty acid binding protein (I-FABP), soluble cluster of differentiation 14 (sCD14), lipopolysaccharide binding protein (LBP) and interleukin 18 (IL-18) by enzyme-linked immunosorbent assay (ELISA), and further gene expression of CD14 and toll-like receptor 4 (TLR4) by real time PCR in circulating leukocytes and peripheral blood mononuclear cells (PBMCs). The participants had either established coronary heart disease (CHD) or underwent computed tomography coronary angiography (CTCA) to assess for coronary atherosclerosis, including total, calcified and soft/mixed plaque volumes.

RESULTS

In the diabetes group, the levels of I-FABP were significantly higher in participants with established CHD or significant stenosis on CTCA compared to the participants with normal arteries or non-significant stenosis, with median 1.67 ng/ml (interquartile range [IQR] 1.02-2.32) vs. median 1.09 ng/ml (IQR 0.82-1.58), p = 0.003. I-FABP was associated with significant coronary artery stenosis by CTCA (> 50%) or previously established CHD in the adjusted analysis (odds ratio [OR] = 2.32, 95% confidence interval [CI]: 1.09-4.95; p = 0.029). The levels of I-FABP correlated also to total coronary plaque volume (r = 0.22, p < 0.05). This association remained significant after adjusting for age, sex, persistent albuminuria, eGFR, statin treatment, diabetes duration and mean time-weighted variables; HbA1c, LDL-cholesterol and systolic blood pressure (OR = 1.97, 95% CI: 1.28-3.01; p = 0.002).

CONCLUSIONS

In this cohort of individuals with long-term type 1 diabetes I-FABP associated significantly with coronary artery stenosis, suggesting a potential role of gut mucosa damage in the process of atherosclerosis in type 1 diabetes.

Gut barrier dysfunction, endotoxemia and inflammatory response in STEMI patients and effect of primary PCI

BACKGROUND

Gut-derived bacterial and endotoxin translocation induce systemic inflammation, which exerts a pivotal pathogenetic role in all phases of atherosclerosis.

OBJECTIVES

To investigate prospectively the gut barrier function, endotoxin translocation and inflammatory response in ST-elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary artery intervention (PPCI).

METHODS

Twenty-seven patients with STEMI that underwent successful PPCI were subjected to peripheral blood sampling at 3-time points; before PPCI (day0), 24 h (day1) and 96 h (day4) after PPCI and were compared with 20 chronic coronary syndrome (CCS) patients and 11 healthy controls. Serum ZO-1, I-FABP and endotoxin concentrations were determined by ELISA. Concentrations of cytokines IL-1β, -6, -8, -10 and TNF-α were determined by flow cytometry.

RESULTS

Patients with STEMI before PPCI (day0) had increased serum ZO-1 and endotoxin, both at significantly higher levels compared to CCS patients. STEMI induced also significant increases of the cytokines IL-6, -8 and -10. After PPCI, a significant improvement of gut barrier integrity (ZO-1) and endotoxemia was observed from the first day. At day4 post PPCI, systemic endotoxin and cytokines IL-6, -8 and -10 levels were reduced to control levels. Serum ZO-1 levels were positively correlated with systemic IL-10 concentrations (r = 0.471).

CONCLUSION

STEMI is associated with gut barrier dysfunction, systemic endotoxemia and inflammatory response, which improve rapidly following successful PPCI.

Pan-genome insights into adaptive evolution of bacterial symbionts in mixed host-microbe symbioses represented by human gut microbiota Bacteroides cellulosilyticus

Animal hosts harbor diverse assemblages of microbial symbionts that play crucial roles in the host's lifestyle. The link between microbial symbiosis and host development remains poorly understood. In particular, little is known about the adaptive evolution of gut bacteria in host-microbe symbioses. Recently, symbiotic relationships have been categorized as open, closed, or mixed, reflecting their modes of inter-host transmission and resulting in distinct genomic features. Members of the genus Bacteroides are the most abundant human gut microbiota and possess both probiotic and pathogenic potential, providing an excellent model for studying pan-genome evolution in symbiotic systems. Here, we determined the complete genome of an novel clinical strain PL2022, which was isolated from a blood sample and performed pan-genome analyses on a representative set of Bacteroides cellulosilyticus strains to quantify the influence of the symbiotic relationship on the evolutionary dynamics. B. cellulosilyticus exhibited correlated genomic features with both open and closed symbioses, suggesting a mixed symbiosis. An open pan-genome is characterized by abundant accessory gene families, potential horizontal gene transfer (HGT), and diverse mobile genetic elements (MGEs), indicating an innovative gene pool, mainly associated with genomic islands and plasmids. However, massive parallel gene loss, weak purifying selection, and accumulation of positively selected mutations were the main drivers of genome reduction in B. cellulosilyticus. Metagenomic read recruitment analyses showed that B. cellulosilyticus members are globally distributed and active in human gut habitats, in line with predominant vertical transmission in the human gut. However, existence and/or high abundance were also detected in non-intestinal tissues, other animal hosts, and non-host environments, indicating occasional horizontal transmission to new niches, thereby creating arenas for the acquisition of novel genes. This case study of adaptive evolution under a mixed host-microbe symbiosis advances our understanding of symbiotic pan-genome evolution. Our results highlight the complexity of genetic evolution in this unusual intestinal symbiont.

Gut microbiota connects the brain and the heart: potential mechanisms and clinical implications

Nowadays, high morbidity and mortality of cardiovascular diseases (CVDs) and high comorbidity rate of neuropsychiatric disorders contribute to global burden of health and economics. Consequently, a discipline concerning abnormal connections between the brain and the heart and the resulting disease states, known as psychocardiology, has garnered interest among researchers. However, identifying a common pathway that physicians can modulate remains a challenge. Gut microbiota, a constituent part of the human intestinal ecosystem, is likely involved in mutual mechanism CVDs and neuropsychiatric disorder share, which could be a potential target of interventions in psychocardiology. This review aimed to discuss complex interactions from the perspectives of microbial and intestinal dysfunction, behavioral factors, and pathophysiological changes and to present possible approaches to regulating gut microbiota, both of which are future directions in psychocardiology.

Targeting the Gut Microbiome to Treat Cardiometabolic Disease

PURPOSE OF REVIEW

Cardiometabolic diseases, which include obesity, type 2 diabetes, and cardiovascular diseases, constitute a worldwide health crisis of unparalleled proportions. The human gut microbiota has emerged as a prominent topic of inquiry in the search for novel treatment techniques. This review summarizes current research on the potential of addressing the gut microbiota to treat cardiometabolic disease.

RECENT FINDINGS

Recent studies have highlighted a complex link between the gut microbiota and host physiology, shedding light on the several processes through which gut microorganisms impact metabolic health, inflammation, and cardiovascular function. Furthermore, a growing corpus of research is available on microbiome-based therapies such as dietary interventions, probiotics, prebiotics, synbiotics, and fecal microbiota transplantation. These therapies show promise as methods for reshaping the gut microbiota and, as a result, improving cardiometabolic outcomes. However, hurdles remain, ranging from the intricacies of microbiome research to the necessity for tailored treatments that take individual microbial variations into consideration, emphasizing the significance of furthering research to bridge the gap between microbiome science and clinical practice. The gut microbiome is a beacon of hope for improving the management of cardiometabolic disease in the age of precision medicine, since its association with their pathophysiology is constantly being unraveled and strengthened. Available studies point to the potential of gut microbiome-based therapeutics, which remains to be tested in appropriately designed clinical trials. Further preclinical research is, however, essential to provide answers to the existing obstacles, with the ultimate goal of enhancing patient care.

Bergamot Polyphenolic Extract Combined with Albedo and Pulp Fibres Counteracts Changes in Gut Microbiota Associated with High-Fat Diet: Implications for Lipoprotein Size Re-Arrangement

Evidence exists that the gut microbiota contributes to the alterations of lipid metabolism associated with high-fat diet (HFD). Moreover, the gut microbiota has been found to modulate the metabolism and absorption of dietary lipids, thereby affecting the formation of lipoproteins occurring at the intestinal level as well as systemically, though the pathophysiological implication of altered microbiota composition in HFD and its role in the development of atherosclerotic vascular disease (ATVD) remain to be better clarified. Recently, evidence has been collected indicating that supplementation with natural polyphenols and fibres accounts for an improvement of HFD-associated intestinal dysbiosis, thereby leading to improved lipidaemic profile. This study aimed to investigate the protective effect of a bergamot polyphenolic extract (BPE) containing 48% polyphenols enriched with albedo and pulp-derived micronized fibres (BMF) in the gut microbiota of HFD-induced dyslipidaemia. In particular, rats that received an HFD over a period of four consecutive weeks showed a significant increase in plasma cholesterol, triglycerides and plasma glucose compared to a normal-fat diet (NFD) group. This effect was accompanied by body weight increase and alteration of lipoprotein size and concentration, followed by high levels of MDA, a biomarker of lipid peroxidation. Treatment with a combination of BPE plus BMF (50/50%) resulted in a significant reduction in alterations of the metabolic parameters found in HFD-fed rats, an effect associated with increased size of lipoproteins. Furthermore, the effect of BPE plus BMF treatment on metabolic balance and lipoprotein size re-arrangement was associated with reduced gut-derived lipopolysaccharide (LPS) levels, an effect subsequent to improved gut microbiota as expressed by modulation of the Gram-negative bacteria Proteobacteria, as well as Firmicutes and Bacteroidetes. This study suggests that nutraceutical supplementation of HFD-fed rats with BPE and BMP or with their combination product leads to restored gut microbiota, an effect associated with lipoprotein size re-arrangement and better lipidaemic and metabolic profiles.

Interactions between Mediterranean Diet Supplemented with Dairy Foods and the Gut Microbiota Influence Cardiovascular Health in an Australian Population

The impact of a Mediterranean diet on the intestinal microbiome has been linked to its health benefits. We aim to evaluate the effects of a Mediterranean diet supplemented with dairy foods on the gut microbiome in Australians at risk of cardiovascular disease. In a randomised controlled cross-over study, 34 adults with a systolic blood pressure ≥120 mmHg and with risk factors for cardiovascular disease were randomly allocated to a Mediterranean diet with 3-4 daily serves of dairy foods (Australian recommended daily intake (RDI) of 1000-1300 mg per day (MedDairy)) or a low-fat (LFD) control diet. Between each 8-week diet, participants underwent an 8-week washout period. Microbiota characteristics of stool samples collected at the start and end of each diet period were determined by 16S rRNA amplicon sequencing. MedDairy-associated effects on bacterial relative abundance were correlated with clinical, anthropometric, and cognitive outcomes. No change in the overall faecal microbial structure or composition was observed with either diet (p > 0.05). The MedDairy diet was associated with changes in the relative abundance of several bacterial taxa, including an increase in Butyricicoccus and a decrease in Colinsella and Veillonella (p < 0.05). Increases in Butyricicoccus relative abundance over 8 weeks were inversely correlated with lower systolic blood pressure (r = -0.38, p = 0.026) and positively correlated with changes in fasting glucose levels (r = 0.39, p = 0.019), specifically for the MedDairy group. No significant associations were observed between the altered taxa and anthropometric or cognitive measures (p > 0.05). Compared to a low-fat control diet, the MedDairy diet resulted in changes in the abundance of specific gut bacteria, which were associated with clinical outcomes in adults at risk of CVD.