The Microbial and Metabolic Signatures of Patients with Stable Coronary Artery Disease

Molecular Mechanisms and Emerging Precision Therapeutics in the Gut Microbiota-Cardiovascular Axis

A microbiome in the gut plays a significant role in cardiovascular health and disease. Dysbiosis is an imbalance in the gut microbiome, leading to multiple cardiovascular diseases (CVD) such as atherosclerosis, hypertension, and heart failure. Gut microbe-derived metabolites such as trimethylamine-N-oxide (TMAO) and short-chain fatty acids (SCFAs) are important mediators of the gut-heart axis. Evaluation of the relationship between the gut microbiome and host biomarkers with CVD requires the integration of metagenomics and metabolomics with meta-omics approaches. The literature review found that microbes and metabolic signatures are associated with the risk and progression of CVD. The development of precision therapeutic approaches for targeting gut microbiota includes preventing adverse microbial effects using probiotics, prebiotics, and the drug-as-bug approach to inhibit harmful metabolites of microbiomes, and fecal microbiota transplantation (FMT). However, the implication and practice of these findings in clinical settings face challenges due to the heterogeneity of study designs, difficulty in the determination of causality, and the impact of confounding factors such as diet, medication, and potential inter-individual gut microbiome variability. Future researchers are recommended to conduct longitudinal studies to further establish both gut microbiome associations with CVD and develop successful precision therapeutics approaches based on the microbiome for the treatment of CVD.

Postoperative delirium after cardiac surgery associated with perioperative gut microbiota dysbiosis: Evidence from human and antibiotic-treated mouse model

BACKGROUND

Research links gut microbiota to postoperative delirium (POD) through the gut-brain axis. However, changes in gut microbiota and fecal short-chain fatty acids (SCFAs) in POD patients during the perioperative period and their association with POD are unclear.

METHODS

We conducted a nested case-control study among patients undergoing off-pump coronary artery bypass grafting, focusing on POD as the main outcome. POD patients were matched 1:1 with non-POD patients based on sociodemographic characteristics, health, and diet. Fecal samples were collected pre- and post-surgery to assess gut microbiota and SCFAs changes. Postoperative fecal samples were transplanted into antibiotic-treated mice to evaluate delirium-like behavior and neuroinflammation.

RESULTS

Out of 120 patients, 60 were matched. Before surgery, gut microbiota in both groups was similar. After surgery, POD patients had lower alpha diversity and distinct microbiota compared to non-POD patients. LEfSe analysis showed POD was linked to increased opportunistic pathogens (Enterococcus) and decreased SCFAs producers (Bacteroides, Ruminococcus, etc.). SCFAs were significantly reduced in POD patients and negatively correlated with delirium severity and plasma inflammation. Mice receiving fecal transplants from POD patients exhibited delirium-like behavior and neuroinflammation.

CONCLUSIONS

Postoperative delirium is associated with gut microbiota dysbiosis, marked by an increase in opportunistic pathogens and a decrease in SCFA-producing genera.

REGISTRATION

Chinese Clinical Trial Registry ChiCTR2300070477.

The sentinels of coronary artery disease: heterogeneous monocytes

Monocytes are heterogeneous immune cells that play a crucial role in the inflammatory response during atherosclerosis, influencing the progression and outcome of the disease. In the pathogenesis of atherosclerotic diseases, such as coronary artery disease (CAD), monocytes not only serve as the initial sensors of endogenous and exogenous pathogenic factors, but also function as intermediators that bridge the circulatory system and localized lesions. In the bloodstream, heterogeneous monocytes, acting as sentinels, are rapidly recruited to atherosclerotic lesions, where they exhibit a heightened capacity to respond to various pathological stimuli upon detecting signals from damaged vascular endothelial cells. Clinical studies have demonstrated that the heterogeneity of monocytes in CAD patients presents both diversity and complexity, varying across different disease subtypes and pathological stages. This review explores the heterogeneity of monocytes in CAD, focusing on alterations in monocyte subset numbers, proportions, and the expression of functional receptors, as well as their correlations with clinical features. Additionally, we propose strategies to enhance the clinical utility value of monocyte heterogeneity and outline future research directions in the field of CAD. With the widespread application of high-parameter flow cytometry and single-cell sequencing technologies, it is anticipated that a comprehensive understanding of monocyte heterogeneity in CAD will be achieved, enabling the identification of disease-specific monocyte subtypes. This could offer new opportunities for improving the diagnosis and treatment of CAD.

Gut dysbiosis narrative in psoriasis: matched-pair approach identifies only subtle shifts correlated with elevated fecal calprotectin

Many studies have reported gut microbiome alterations in psoriasis patients, suggesting dysbiosis. While evidence for dysbiosis and its link to pathogenesis remains inconclusive, murine models of psoriasis suggest that gut microbiome alterations develop in response to psoriasis-like inflammation. Hence, the dominant narrative about gut microbiome alterations' impact on disease should be evaluated critically with more data and a well-powered approach. In this case-control study, we used deep sequencing of fecal samples from 53 psoriasis patients and 47 healthy donors to reconstruct the strain/species-level content of the gut microbiome. Unlike previous studies, we first identified matched pairs for each patient with healthy donors to adjust for microbiome variability and increase power. We found no evidence for depleted gut community diversity and apparent divergence in structure between patients and healthy individuals. However, our matched-pair approach identified a subtle but systematic increase in select bacteria among patients, e.g., Megasphaera elsdenii and Eubacterium CAG 180. We next showed that these enriched species were correlated with elevated biomarkers of intestinal and systemic inflammation and liver function. Functionally, one of the top species, Megasphaera elsdenii, is a potent lactate utilizer in the context of intestinal lactic acidosis and inflammation. While our findings hardly support overt dysbiosis in the large intestine, the observed microbial changes correlate with moderately elevated calprotectin, albeit at levels not enough to diagnose ongoing inflammation. Hence, the sources of elevated inflammatory markers in patients' intestines remain unclear and warrant further investigation to clarify their cause-and-effect relationship with the disease.

IMPORTANCE

With sufficient taxonomic resolution and sample size, this study critically evaluates new and published data on the gut microbiome in psoriasis patients. It shows that observed taxonomic changes in patients are modest and do not meet strict criteria for gut dysbiosis, at least in the large intestine. Instead, observed taxonomic changes in psoriasis patients can be explained by the microbial response to possible low-grade inflammation with unknown localization in the intestine and unclear impact on the host. The authors point out that published endoscopic data point to the small intestine as the site of gut inflammation. Therefore, further research focused on the small intestine would be informative to clarify the hypothetical gut-psoriasis link.

Multi-omics evaluation of clinical-grade human umbilical cord-derived mesenchymal stem cells in synergistic improvement of aging related disorders in a senescence-accelerated mouse model

BACKGROUND

The prevalence of age-related disorders, particularly in neurological and cardiovascular systems, is an increasing global health concern. Mesenchymal stem cell (MSC) therapy, particularly using human umbilical cord-derived MSCs (HUCMSCs), has shown promise in mitigating these disorders. This study investigates the effects of HUCMSCs on aging-related conditions in a senescence-accelerated mouse model (SAMP8), with a focus on DNA damage, gut microbiota alterations, and metabolic changes.

METHODS

SAMP8 mice were treated with clinical-grade HUCMSCs via intraperitoneal injections. Behavioral and physical assessments were conducted to evaluate cognitive and motor functions. The Single-Strand Break Mapping at Nucleotide Genome Level (SSiNGLe) method was employed to assess DNA single-strand breaks (SSBs) across the genome, with particular attention to exonic regions and transcription start sites. Gut microbiota composition was analyzed using 16S rRNA sequencing, and carboxyl metabolomic profiling was performed to identify changes in circulating metabolites.

RESULTS

HUCMSC treatment significantly improved motor coordination and reduced anxiety in SAMP8 mice. SSiNGLe analysis revealed a notable reduction in DNA SSBs in MSC-treated mice, especially in critical genomic regions, suggesting that HUCMSCs may mitigate age-related DNA damage. The functional annotation of the DNA breaktome indicated a potential link between reduced DNA damage and altered metabolic pathways. Additionally, beneficial alterations in gut microbiota were observed, including an increase in short-chain fatty acid (SCFA)-producing bacteria, which correlated with improved metabolic profiles.

CONCLUSION

The administration of HUCMSCs in SAMP8 mice not only reduces DNA damage but also induces favorable changes in gut microbiota and metabolism. The observed alterations in DNA break patterns, along with specific changes in microbiota and metabolic profiles, suggest that these could serve as potential biomarkers for evaluating the efficacy of HUCMSCs in treating age-related disorders. This highlights a promising avenue for the development of new therapeutic strategies that leverage these biomarkers, to enhance the effectiveness of HUCMSC-based treatments for aging-associated diseases.

Metformin's dual impact on Gut microbiota and cardiovascular health: A comprehensive analysis

Cardiovascular diseases (CVD) cause significant global morbidity, mortality and public health burden annually. CVD alters richness, diversity, and composition of Gut microbiota along with RAS and histopathological differences. Present study explores Metformin role in mitigating doxorubicin induced cardiovascular toxicity/remodeling. Animals were divided into 4 groups with n=6: Group I (N. Control) free access to diet and water; Group II (MET. Control) on oral Metformin (250 mg/kg) daily; Group III (DOX. Control) alternate day intraperitoneal Doxorubicin (3 mg/kg) totaling 18 mg/kg; Group IV (DOX. MET. Control) received both daily oral Metformin (250 mg/kg) and alternate day Doxorubicin (3 mg/kg). Gut microbial analysis was made from stool before animals were sacrificed for biochemical and histopathological analysis. Significant alterations were observed in ɑ and β-diversity with new genus from Firmicutes, specifically Clostridia_UCG-014, Eubacterium ruminantium, and Tunicibacter, were prevalent in both the DOX. Control and DOX.MET groups. Proteobacteria, represented by Succinivibrio, were absent in all groups. Additionally, Parabacteroides from the Bacteroidia phylum was absent in all groups except the N. control. In the DOX.MET Control group, levels of Angiotensin II ( 7.75± 0.49 nmol/min, p<0.01) and Renin (2.60±0.26 ng/ml/hr) were significantly reduced. Conversely, levels of CK-MB, Fibrinogen, Troponin, CRP ( p < 0.0001), and TNFɑ (p < 0.05) were elevated. Histopathological examination revealed substantial cardiac changes, including Fibrinogen and fat deposition and eosinophilic infiltration, as well as liver damage characterized by binucleated cells and damaged hepatocytes, along with altered renal tissues in the DOX.MET.Control group. The findings suggest that MET. significantly modifies gut microbiota, particularly impacting the Firmicutes and Proteobacteria phyla. The reduction in Angiotensin II levels, alongside increased inflammatory markers and myocardial damage, highlights the complex interactions and potential adverse effects associated with MET therapy on cardiovascular health.

Unravelling the Gut Microbiome Role in Cardiovascular Disease: A Systematic Review and a Meta-Analysis

A notable shift in understanding the human microbiome's influence on cardiovascular disease (CVD) is underway, although the causal association remains elusive. A systematic review and meta-analysis were conducted to synthesise current knowledge on microbial taxonomy and metabolite variations between healthy controls (HCs) and those with CVD. An extensive search encompassing three databases identified 67 relevant studies (2012-2023) covering CVD pathologies from 4707 reports. Metagenomic and metabolomic data, both qualitative and quantitative, were obtained. Analysis revealed substantial variability in microbial alpha and beta diversities. Moreover, specific changes in bacterial populations were shown, including increased Streptococcus and Proteobacteria and decreased Faecalibacterium in patients with CVD compared with HC. Additionally, elevated trimethylamine N-oxide levels were reported in CVD cases. Biochemical parameter analysis indicated increased fasting glucose and triglycerides and decreased total cholesterol and low- and high-density lipoprotein cholesterol levels in diseased individuals. This study revealed a significant relationship between certain bacterial species and CVD. Additionally, it has become clear that there are substantial inconsistencies in the methodologies employed and the reporting standards adhered to in various studies. Undoubtedly, standardising research methodologies and developing extensive guidelines for microbiome studies are crucial for advancing the field.

Gut Microbiota and Its Metabolites: The Emerging Bridge Between Coronary Artery Disease and Anxiety and Depression?

The increasing studies indicated that cardiovascular diseases, such as coronary artery disease (CAD), usually induce and exacerbate psychological problems, including anxiety and depression. These psychological issues are admitted as independent risk factors of heart disease as well. The interaction between CAD and anxiety and depression deteriorates the development and prognosis of CAD, which severely threatens the quality of life of patients. Although the existing mechanisms revealed the pathological relationship between CAD and anxiety and depression, there are few studies investigating the correlation between CAD and anxiety and depression from the aspect of gut microbiota (GM) and its metabolites. Therefore, in this review, we summarized whether GM and its metabolites are the emergent bridge between CAD and anxiety and depression. The results showed that there are four kinds of jointly up-regulated bacteria (i.e., Staphylococcus, Escherichia coli, Helicobacter pylori, and Shigella) and five kinds of jointly down-regulated bacteria (i.e., Prevotella, Lactobacillus, Faecalibacterium prausnitzii, Collinsella, and Bifidobacterium) in CAD as well as anxiety and depression. In addition, in CAD and anxiety and depression, the dysbiosis of the former four kinds of bacterium frequently leads to the outburst of inflammatory response, and the dysbiosis of the latter five kinds of bacterium is usually related to the metabolic abnormality of short-chain fatty acids, bile acids, and branched-chain amino acids. Therefore, we believe that GM and its metabolites act as the emergent bridge between CAD and anxiety and depression. The findings of this review provide novel insights and approaches for the clinical treatment of patients with both CAD and anxiety and depression.

The Dynamic Changes of Brassica napus Seed Microbiota across the Entire Seed Life in the Field

The seed microbiota is an important component given by nature to plants, protecting seeds from damage by other organisms and abiotic stress. However, little is known about the dynamic changes and potential functions of the seed microbiota during seed development. In this study, we investigated the composition and potential functions of the seed microbiota of rapeseed (Brassica napus). A total of 2496 amplicon sequence variants (ASVs) belonging to 504 genera in 25 phyla were identified, and the seed microbiota of all sampling stages were divided into three groups. The microbiota of flower buds, young pods, and seeds at 20 days after flowering (daf) formed the first group; that of seeds at 30 daf, 40 daf and 50 daf formed the second group; that of mature seeds and parental seeds were clustered into the third group. The functions of seed microbiota were identified by using PICRUSt2, and it was found that the substance metabolism of seed microbiota was correlated with those of the seeds. Finally, sixty-one core ASVs, including several potential human pathogens, were identified, and a member of the seed core microbiota, Sphingomonas endophytica, was isolated from seeds and found to promote seedling growth and enhance resistance against Sclerotinia sclerotiorum, a major pathogen in rapeseed. Our findings provide a novel perspective for understanding the composition and functions of microbiota during seed development and may enhance the efficiency of mining beneficial seed microbes.

miMatch: a microbial metabolic background matching tool for mitigating host confounding in metagenomics research

Metagenomic research faces a persistent challenge due to the low concordance across studies. While matching host confounders can mitigate the impact of individual differences, the influence of factors such as genetics, environment, and lifestyle habits on microbial profiles makes it exceptionally challenging to create fully matched cohorts. The microbial metabolic background, which modulates microbial composition, reflects a cumulative impact of host confounders, serving as an ideal baseline for microbial sample matching. In this study, we introduced miMatch, an innovative metagenomic sample-matching tool that uses microbial metabolic background as a comprehensive reference for host-related variables and employs propensity score matching to build case-control pairs, even in the absence of host confounders. In the simulated datasets, miMatch effectively eliminated individual metabolic background differences, thereby enhancing the accuracy of identifying differential microbial patterns and reducing false positives. Moreover, in real metagenomic data, miMatch improved result consistency and model generalizability across cohorts of the same disease. A user-friendly web server (https://www.biosino.org/iMAC/mimatch) has been established to promote the integration of multiple metagenomic cohorts, strengthening causal relationships in metagenomic research.

Relationship of Acylcarnitines to Myocardial Ischemic Remodeling and Clinical Manifestations in Chronic Heart Failure

BACKGROUND

Progressive myocardial remodeling (MR) in chronic heart failure (CHF) leads to aggravation of systolic dysfunction (SD) and clinical manifestations. Identification of metabolomic markers of these processes may help in the search for new therapeutic approaches aimed at achieving reversibility of MR and improving prognosis in patients with CHF.

METHODS

To determine the relationship between plasma acylcarnitine (ACs) levels, MR parameters and clinical characteristics, in patients with CHF of ischemic etiology (n = 79) and patients with coronary heart disease CHD (n = 19) targeted analysis of 30 ACs was performed by flow injection analysis mass spectrometry.

RESULTS

Significant differences between cohorts were found for the levels of 11 ACs. Significant positive correlations (r > 0.3) between the medium- and long-chain ACs (MCACs and LCACs) and symptoms (CHF NYHA functional class (FC); r = 0.31-0.39; p < 0.05); negative correlation (r = -0.31-0.34; p < 0.05) between C5-OH and FC was revealed. Positive correlations of MCACs and LCACs (r = 0.31-0.48; p < 0.05) with the left atrium size and volume, the right atrium volume, right ventricle, and the inferior vena cava sizes, as well as the pulmonary artery systolic pressure level were shown. A negative correlation between C18:1 and left ventricular ejection fraction (r = -0.31; p < 0.05) was found. However, a decrease in levels compared to referent values of ACs with medium and long chain lengths was 50% of the CHF-CHD cohort. Carnitine deficiency was found in 6% and acylcarnitine deficiency in 3% of all patients with chronic heart disease.

CONCLUSIONS

ACs may be used in assessing the severity of the clinical manifestations and MR. ACs are an important locus to study in terms of altered metabolic pathways in patients with CHF of ischemic etiology and SD. Further larger prospective trials are warranted and needed to determine the potential benefits to treat patients with CV diseases with aberrate AC levels.

Oxidative Stress, Inflammation, Gut Dysbiosis: What Can Polyphenols Do in Inflammatory Bowel Disease?

Inflammatory bowel disease (IBD) is a long-term, progressive, and recurrent intestinal inflammatory disorder. The pathogenic mechanisms of IBD are multifaceted and associated with oxidative stress, unbalanced gut microbiota, and aberrant immune response. Indeed, oxidative stress can affect the progression and development of IBD by regulating the homeostasis of the gut microbiota and immune response. Therefore, redox-targeted therapy is a promising treatment option for IBD. Recent evidence has verified that Chinese herbal medicine (CHM)-derived polyphenols, natural antioxidants, are able to maintain redox equilibrium in the intestinal tract to prevent abnormal gut microbiota and radical inflammatory responses. Here, we provide a comprehensive perspective for implementing natural antioxidants as potential IBD candidate medications. In addition, we demonstrate novel technologies and stratagems for promoting the antioxidative properties of CHM-derived polyphenols, including novel delivery systems, chemical modifications, and combination strategies.