Gut microbiota-derived trimethylamine N-oxide is associated with poor prognosis in patients with heart failure

Trimethylamine-N-Oxide (TMAO) as a Rising-Star Metabolite: Implications for Human Health

The intestinal microbiota, hosting trillions of microorganisms that inhabit the gastrointestinal tract, functions as a symbiotic organism that plays a crucial role in regulating health by producing biologically active molecules that can enter systemic circulation. Among them, trimethylamine-N-oxide (TMAO), an organic compound derived from dietary sources and microbial metabolism, has emerged as a critical biomarker linking diet, the gut microbiota, and the host metabolism to various pathological conditions. This comprehensive review highlights TMAO's biosynthesis, physiological functions, and clinical significance, focusing on its mechanistic contributions to cardiovascular and neurodegenerative diseases. Notably, TMAO-mediated pathways include endothelial dysfunction, inflammation via NLRP3 inflammasome activation, and cholesterol metabolism disruption, which collectively accelerate atherosclerosis and disease progression. Nonetheless, this work underscores the innovative potential of targeting TMAO through dietary, nutraceutical, and microbiota-modulating strategies to mitigate its pathological effects, marking a transformative approach in the prevention and management of TMAO-related disorders.

Gut microbiota and risk of heart failure in European population-A comprehensive Mendelian randomization study

AIMS

Gut dysbiosis is proven to be involved in the pathogenesis and progression of heart failure (HF). Hindering the detrimental effects of gut-heart axis is an emerging trend. Our goal is to investigate the causal relationship between gut microbiota and HF, with the aim of facilitating future exploration of microbiome-targeted approaches to prevent and delay the progression of HF.

METHODS AND RESULTS

Two-sample Mendelian randomization (MR) analysis was applied to investigate the causal association of the gut microbiome with HF among individuals of European ancestry. Genetic variants associated with the 196 bacterial taxa from MiBioGen consortium were used as exposure data, summary statistics for HF derived from Heart Failure Molecular Epidemiology for Therapeutic Targets (HERMES) consortium were used as outcome data. Five MR methods were applied, including inverse variance weighted, maximum likelihood, MR-Egger, weighted median, and weighted mode. Reverse causality of instrumental variables (IVs) was tested by MR Steiger test of directionality. Strength of IVs was evaluated by F-statistics. Cochrane's Q test, MR-Egger regression analysis, and MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO) tests were used to detect heterogeneity and pleiotropy. Leave-one-out method was used for testing the stability of results. Seven microbiomes were found to be associated with HF. Five of them were associated with higher risks of developing HF, these included Order_Selenomonadales (odds ratio [OR] = 1.11, P = 0.024), Family_Peptococcaceae (OR = 1.07, P = 0.045), Genus_Eubacterium eligens group (OR = 1.14, P = 0.022), Genus_Eubacterium oxidoreducens group (OR = 1.12, P = 0.011) and Genus_Flavonifractor (OR = 1.14, P = 0.012). Genus_Anaerostipes and Order_Bacillales were associated with lower risks of HF (OR = 0.90, P = 0.014; OR = 0.95, P = 0.042, respectively). Evidence of pleiotropy or heterogeneity was not observed.

CONCLUSIONS

We identified seven intestinal microbiomes that were causally associated with HF at the level of gene prediction. This study will help with the discovery of potential preventive and therapeutic targets for HF.

Circulating trimethylamine N-oxide and cardiovascular, cerebral, and renal diseases including mortality: Umbrella review of published systematic reviews and meta-analyses

AIMS

Several systematic reviews/meta-analyses of observational studies have demonstrated associations between circulating trimethylamine-N-oxide (TMAO) and cardiovascular, cerebral, and renal diseases, including mortality. However, causal roles for TMAO in these diseases are controversial. Interventions are lacking to show whether lowering TMAO in clinical trials could reduce the risks of these diseases. TMAO could still serve as a prognostic marker for the mentioned outcomes, but investigating this potential role requires robust methodologies. We conducted a systematic search and critical evaluation of published systematic reviews/meta-analyses in the field.

DATA SYNTHESIS

We identified 27 systematic reviews/meta-analyses on the association between TMAO and stroke (n = 7), cardiovascular disease including cause-specific and/or all-cause mortality (n = 14), and other related outcomes (n = 6). The majority of the systematic reviews/meta-analyses found higher blood TMAO concentrations in patients who were positive for the outcomes. Primary studies included populations with multiple risk factors for the given outcomes and did not sufficiently account for potential confounders. Prospective studies examining associations between baseline TMAO and subsequent disease outcomes in healthy populations were entirely absent. Furthermore, we identified serious flaws in methods, conduct and reporting in the majority of the published systematic reviews/meta-analyses, thus leading to critically low confidence in the results.

CONCLUSIONS

High quality systematic reviews/meta-analyses examining the associations between TMAO and cardiovascular or cerebral disease are needed to examine potential causal and/or predictive roles of TMAO in these diseases. This study is registered at the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42024534940).

Association between trimethylamine N-oxide and prognosis of patients with myocardial infarction: a meta-analysis

Background

Trimethylamine N-oxide (TMAO) has been widely explored and considered as a biomarker for adverse cardiovascular events. However, the relationships between TMAO adverse cardiovascular events are inconsistent in patients. Therefore, this meta-analysis aimed to estimate association between TMAO levels and the prognosis of patients with myocardial infarction (MI).

Methods

We searched PubMed, EMBASE, the Cochrane Library, and Web of Science from inception to July 2, 2023, to retrieve all relevant clinical trials. Associations between TMAO levels, major adverse cardiovascular events (MACE), all-cause mortality, recurrent MI, stroke, etc., were systematically addressed. Outcomes included MACE, all-cause mortality, recurrent MI, rehospitalization caused by heart failure, stroke, revascularization, SYNTAX score, and multivessel disease. A fixed/random-effects model should be adopted to calculate the pooled estimates. Besides, funnel plot, Begg's test and Egger' test were used to test publication bias.

Results

A total of nine studies were included in our meta-analysis. Our results indicated that higher TMAO levels were associated with greater risk of MACE (RR = 1.94; 95% CI = 1.39 to 2.73), all-cause mortality (RR = 1.56; 95% CI = 1.00 to 2.44), and MI (RR = 1.21; 95% CI = 1.01 to 1.45). No significant association was found in stroke, SYNTAX, and multivessel disease. Besides, our results reported that the association between TMAO levels and MACE after MI was not affected by the geographic localization.

Conclusion

This study was the first meta-analysis that showed a significant positive association of TMAO levels with MACE, all-cause mortality, and recurrent MI in patients with MI.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=460400, PROSPERO (CRD42023460400).

Gut microbiota metabolite trimethylamine N-oxide promoted NAFLD progression by exacerbating intestinal barrier disruption and intrahepatic cellular imbalance

Non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide, with the gut microbiota and its metabolites are important regulators of its progression. Trimethylamine N-oxide (TMAO), a metabolite of the gut microbiota, has been closely associated with various metabolic diseases, but its relationship with NAFLD remains to be elucidated. In this study, we found that fecal TMAO levels correlated with NAFLD severity. Moreover, TMAO promoted lipid deposition in HepG2 fatty liver cells and exacerbated hepatic steatosis in NAFLD rats. In the colon, TMAO undermined the structure and function of the intestinal barrier at various levels, further activated the TLR4/MyD88/NF-κB pathway, and inhibited the WNT/β-catenin pathway. In the liver, TMAO induced endothelial dysfunction with capillarization of liver sinusoidal endothelial cells, while modulating macrophage polarization. In conclusion, our study suggests that gut microbiota metabolite TMAO promotes NAFLD progression by impairing the gut and liver and that targeting TMAO could be an alternative therapeutic strategy for NAFLD.

Healthy and unhealthy plant-based diets and the risk of cardiovascular diseases: The Rotterdam study and updated meta-analysis

BACKGROUND

Consumption of more plant-based foods is gaining popularity, but the role of healthy versus unhealthy plant-based diets in cardiovascular disease (CVD) risk remains inconclusive.

OBJECTIVES

We investigated associations of plant-based diet indices (PDIs) with incident CVDs in a prospective cohort study and conducted an updated meta-analysis.

METHODS

We included 3507 men and 5345 women of the population-based Rotterdam Study. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for CVD, coronary heart disease (CHD) and stroke per SD increment of an overall PDI, healthy PDI (hPDI) and unhealthy PDI (uPDI), among men and women separately. We combined our findings with previously published effect estimates in an updated meta-analysis.

RESULTS

We documented 2015 CVD cases (1231 CHD and 952 stroke) during 107,290 person-years follow-up. Among men, the PDI and hPDI were associated with a 7 % (HR 0.93, 95 % CI 0.87-0.99) and 8 % (HR 0.92, 95 % CI 0.86-0.98) lower CVD risk. Among women, there was evidence suggesting a U-shaped association of the PDI with stroke (pnon-linearity < 0.01). In meta-analyses including up to 43,067 incident CVD cases among 359,740 participants from nine studies, the PDI and hPDI, were associated with a lower CVD riskand the uPDI with a higher CVD risk (pooled HRs [95 % CI], per SD, PDI: 0.94 [0.91-0.97], I2 = 50.4 %; hPDI: 0.94 [0.91-0.98], I2 = 74.7 %; uPDI: 1.03 [1.01-1.06], I2 = 49.0 %).

CONCLUSIONS

Our findings support recommendations to consume relatively more healthy plant-based foods for CVD prevention. Potential differences by sex and non-linear associations warrant further investigation.

Trimethylamine N-oxide: a meta-organismal axis linking the gut and fibrosis

BACKGROUND

Tissue fibrosis is a common pathway to failure in many organ systems and is the cellular and molecular driver of myriad chronic diseases that are incompletely understood and lack effective treatment. Recent studies suggest that gut microbe-dependent metabolites might be involved in the initiation and progression of fibrosis in multiple organ systems.

MAIN BODY OF THE MANUSCRIPT

In a meta-organismal pathway that begins in the gut, gut microbiota convert dietary precursors such as choline, phosphatidylcholine, and L-carnitine into trimethylamine (TMA), which is absorbed and subsequently converted to trimethylamine N-oxide (TMAO) via the host enzyme flavin-containing monooxygenase 3 (FMO3) in the liver. Chronic exposure to elevated TMAO appears to be associated with vascular injury and enhanced fibrosis propensity in diverse conditions, including chronic kidney disease, heart failure, metabolic dysfunction-associated steatotic liver disease, and systemic sclerosis.

CONCLUSION

Despite the high prevalence of fibrosis, little is known to date about the role of gut dysbiosis and of microbe-dependent metabolites in its pathogenesis. This review summarizes recent important advances in the understanding of the complex metabolism and functional role of TMAO in pathologic fibrosis and highlights unanswered questions.

Relationship between coagulopathy score and ICU mortality: Analysis of the MIMIC-IV database

Objective

Coagulopathy score has been applied as a new prognostic indicator for sepsis, heart failure and acute respiratory failure. However, its ability to forecast intensive care unit (ICU) mortality in patients with an acute cerebral hemorrhage (ICH) has not been assessed. The purpose of this study was to clarify the relationship between ICU mortality and early coagulation problem score.

Methods

Data from the Medical Information Mart for Intensive Care (MIMIC-IV) (v2.0) database were used in this retrospective cohort analysis. The association between the coagulation disorder score and ICU mortality was examined using multivariate logistic regression. Furthermore, the impact of additional variables on the results was investigated by a subgroup analysis.

Results

3174 patients (57.3 % male) were enrolled in total. The ICU mortality reached 18.2 %. After adjusting for potential confounders, the ICU mortality of patients rose with the increase of coagulation disorder score. The ROC curve revealed the predictive accuracy of coagulation dysfunction score to mortality in patients with ICU. The coagulation disorder score had a lower AUC value (0.601, P < 0.001) than the SAPSII(AUCs of 0.745[95 % CI, 0.730-0.761]) and the combined indicators(AUCs of 0.752[95 % CI, 0.737-0.767]), but larger than single indicators platelet, INR and APTT. In the subgroup analysis, most subgroups showed no significant interaction, but only age showed significant interaction in the adjusted model.

Conclusion

The coagulopathy score and ICU mortality were found to be strongly positively correlated in this study, and its ability to predict ICU mortality was better than that of a single measure (platelet, INR, or APTT), but worse than that of the SAPSII score, GCS system.

Human Gut Microbiota in Cardiovascular Disease

The gut ecosystem, termed microbiota, is composed of bacteria, archaea, viruses, protozoa, and fungi and is estimated to outnumber human cells. Microbiota can affect the host by multiple mechanisms, including the synthesis of metabolites and toxins, modulating inflammation and interaction with other organisms. Advances in understanding commensal organisms' effect on human conditions have also elucidated the importance of this community for cardiovascular disease (CVD). This effect is driven by both direct CV effects and conditions known to increase CV risk, such as obesity, diabetes mellitus (DM), hypertension, and renal and liver diseases. Cardioactive metabolites, such as trimethylamine N -oxide (TMAO), short-chain fatty acids (SCFA), lipopolysaccharides, bile acids, and uremic toxins, can affect atherosclerosis, platelet activation, and inflammation, resulting in increased CV incidence. Interestingly, this interaction is bidirectional with microbiota affected by multiple host conditions including diet, bile acid secretion, and multiple diseases affecting the gut barrier. This interdependence makes manipulating microbiota an attractive option to reduce CV risk. Indeed, evolving data suggest that the benefits observed from low red meat and Mediterranean diet consumption can be explained, at least partially, by the changes that these diets may have on the gut microbiota. In this article, we depict the current epidemiological and mechanistic understanding of the role of microbiota and CVD. Finally, we discuss the potential therapeutic approaches aimed at manipulating gut microbiota to improve CV outcomes. © 2024 American Physiological Society. Compr Physiol 14:5449-5490, 2024.

The Mediterranean Diet, Its Microbiome Connections, and Cardiovascular Health: A Narrative Review

The Mediterranean diet (MD), rich in minimally processed plant foods and in monounsaturated fats but low in saturated fats, meat, and dairy products, represents one of the most studied diets for cardiovascular health. It has been shown, from both observational and randomized controlled trials, that MD reduces body weight, improves cardiovascular disease surrogates such as waist-to-hip ratios, lipids, and inflammation markers, and even prevents the development of fatal and nonfatal cardiovascular disease, diabetes, obesity, and other diseases. However, it is unclear whether it offers cardiovascular benefits from its individual components or as a whole. Furthermore, limitations in the methodology of studies and meta-analyses have raised some concerns over its potential cardiovascular benefits. MD is also associated with characteristic changes in the intestinal microbiota, mediated through its constituents. These include increased growth of species producing short-chain fatty acids, such as Clostridium leptum and Eubacterium rectale, increased growth of Bifidobacteria, Bacteroides, and Faecalibacterium prausnitzii species, and reduced growth of Firmicutes and Blautia species. Such changes are known to be favorably associated with inflammation, oxidative status, and overall metabolic health. This review will focus on the effects of MD on cardiovascular health through its action on gut microbiota.

Pulmonary Hypertension and the Gut Microbiome

The gut microbiome and its associated metabolites are integral to the maintenance of gut integrity and function. There is increasing evidence that its alteration, referred to as dysbiosis, is involved in the development of a systemic conditions such as cardiovascular disease (e.g., systemic hypertension, atherosclerosis). Pulmonary hypertension (PH) is a condition characterised by progressive remodelling and vasoconstriction of the pulmonary circulation, ultimately leading to right ventricular failure and premature mortality if untreated. Initial studies have suggested a possible association between dysbiosis of the microbiome and the development of PH. The aim of this article is to review the current experimental and clinical data with respect to the potential interaction between the gut microbiome and the pathophysiology of pulmonary hypertension. It will also highlight possible new therapeutic targets that may provide future therapies.

Host-microbe tryptophan partitioning in cardiovascular diseases

The functional interdependencies between the molecular components of a biological process demand for a network medicine platform that integrates systems biology and network science, to explore the interactions among biological components in health and disease. Access to large-scale omics datasets (genomics, transcriptomics, proteomics, metabolomics, metagenomics, phenomics, etc.) has significantly advanced our opportunity along this direction. Studies utilizing these techniques have begun to provide us with a deeper understanding of how the interaction between the intestinal microbes and their host affects the cardiovascular system in health and disease. Within the framework of a multiomics network approach, we highlight here how tryptophan metabolism may orchestrate the host-microbes interaction in cardiovascular diseases and the implications for precision medicine and therapeutics, including nutritional interventions.

Insights into the associations between the gut microbiome, its metabolites, and heart failure

Heart failure (HF) is the end stage of most cardiovascular diseases and remains a significant health problem globally. We aimed to assess whether patients with left ventricular ejection fraction ≤45% had alterations in both the gut microbiome profile and production of associated metabolites when compared with a healthy cohort. We also examined the associated inflammatory, metabolomic, and lipidomic profiles of patients with HF. This single center, observational study, recruited 73 patients with HF and 59 healthy volunteers. Blood and stool samples were collected at baseline and 6-mo follow-up, along with anthropometric and clinical data. When compared with healthy controls, patients with HF had reduced gut bacterial alpha diversity at follow-up (P = 0.004) but not at baseline. The stool microbiota of patients with HF was characterized by a depletion of operational taxonomic units representing commensal Clostridia at both baseline and follow-up. Patients with HF also had significantly elevated baseline plasma acetate (P = 0.007), plasma trimethylamine-N-oxide (TMAO) (P = 0.003), serum soluble CD14 (sCD14; P = 0.005), and soluble CD163 (sCD163; P = 0.004) levels compared with healthy controls. Furthermore, patients with HF had a distinct metabolomic and lipidomic profile at baseline when compared with healthy controls. Differences in the composition of the gut microbiome and the levels of associated metabolites were observed in patients with HF when compared with a healthy cohort. This was also associated with an altered metabolomic and lipidomic profile. Our study identifies microorganisms and metabolites that could represent new therapeutic targets and diagnostic tools in the pathogenesis of HF.NEW & NOTEWORTHY We found a reduction in gut bacterial alpha diversity in patients with heart failure (HF) and that the stool microbiota of patients with HF was characterized by depletion of operational taxonomic units representing commensal Clostridia at both baseline and follow-up. Patients with HF also had altered bacterial metabolites and increased inflammatory profiles compared with healthy controls. A distinct metabolomic and lipidomic profile was present in patients with HF at baseline when compared with healthy controls.

From heart failure and kidney dysfunction to cardiorenal syndrome: TMAO may be a bridge

The study of trimethylamine oxide (TMAO), a metabolite of gut microbiota, and heart failure and chronic kidney disease has made preliminary achievements and been summarized by many researchers, but its research in the field of cardiorenal syndrome is just beginning. TMAO is derived from the trimethylamine (TMA) that is produced by the gut microbiota after consumption of carnitine and choline and is then transformed by flavin-containing monooxygenase (FMO) in the liver. Numerous research results have shown that TMAO not only participates in the pathophysiological progression of heart and renal diseases but also significantly affects outcomes in chronic heart failure (CHF) and chronic kidney disease (CKD), besides influencing the general health of populations. Elevated circulating TMAO levels are associated with adverse cardiovascular events such as HF, myocardial infarction, and stroke, patients with CKD have a poor prognosis as well. However, no study has confirmed an association between TMAO and cardiorenal syndrome (CRS). As a syndrome in which heart and kidney diseases intersect, CRS is often overlooked by clinicians. Here, we summarize the research on TMAO in HF and kidney disease and review the existing biomarkers of CRS. At the same time, we introduced the relationship between exercise and gut microbiota, and appropriately explored the possible mechanisms by which exercise affects gut microbiota. Finally, we discuss whether TMAO can serve as a biomarker of CRS, with the aim of providing new strategies for the detection, prognostic, and treatment evaluation of CRS.

Gut microbiota metabolite TMAO promoted lipid deposition and fibrosis process via KRT17 in fatty liver cells in vitro

Non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide but still lacks specific treatment modalities. The gut microbiota and its metabolites have been shown to be intimately involved in NAFLD development, participating in and regulating disease progression. Trimethylamine N-oxide (TMAO), a metabolite highly dependent on the gut microbiota, has been shown to play deleterious regulatory roles in cardiovascular disease, but the relationship between it and NAFLD lacks validation from basic experiments. This research applied TMAO intervention by constructing fatty liver cell models in vitro to observe its effect on fatty liver cells and potential key genes and performed siRNA interference on the gene to verify the action. The results showed that TMAO intervention promoted the appearance of more red-stained lipid droplets in Oil-red O staining results, increased triglyceride (TG) levels and increased mRNA levels of liver fibrosis-related genes, and also identified one of the key genes, keratin17 (KRT17) via transcriptomics. Following the reduction in its expression level, under the same treatment, there were decreased red-stained lipid droplets, decreased TG levels, decreased indicators of impaired liver function as well as decreased mRNA levels of liver fibrosis-related genes. In conclusion, the gut microbiota metabolite TMAO could promote lipid deposition and fibrosis process via the KRT17 gene in fatty liver cells in vitro.

Prognostic Nutritional Index (PNI) as a Predictor in Patients with Metabolic Syndrome and Heart Failure

Purpose

There is a lack of research on nutritional status and poor prognosis in patients with metabolic syndrome and heart failure. This study evaluated the relationship between nutritional status as defined by the PNI and adverse outcomes in patients with metabolic syndrome and heart failure.

Methods

A total of 1048 heart failure patients with metabolic syndrome admitted to the Heart Center of the First Affiliated Hospital of Xinjiang Medical University from January 2015 to December 2019 were consecutively. PNI was used to assess their nutritional status.

Results

A total of 51.0% of the patients were in the nonmalnutrition group (PNI≥45), 27.9% were in the mild malnutrition group (40≤PNI<45), and 21.1% of patients were in the malnutrition group (PNI<40). At 36 months of follow-up, after adjusting for other confounding factors, malnutrition (PNI<40) was independently associated with all-cause death (HR: 1.787, 95% CI: 1.451-2.201, P<0.001) and cardiovascular death (HR: 1.837, 95% CI: 1.467-2.301, P<0.001). PNI showed additional prognostic predictive value when included in the established risk factor model, both for all-cause death (AUC: 0.620, 95% CI: 0.579-0.661, P<0.001) and cardiovascular death (AUC: 0.596, 95% CI: 0.555-0.636, P<0.001).

Conclusion

In patients with metabolic syndrome and heart failure, malnutrition assessed by PNI is an independent predictor for all-cause death and cardiovascular death, and PNI is negatively correlated with the occurrence of adverse outcomes.

Mechanisms, therapeutic implications, and methodological challenges of gut microbiota and cardiovascular diseases: a position paper by the ESC Working Group on Coronary Pathophysiology and Microcirculation

The human gut microbiota is the microbial ecosystem in the small and large intestines of humans. It has been naturally preserved and evolved to play an important role in the function of the gastrointestinal tract and the physiology of its host, protecting from pathogen colonization, and participating in vitamin synthesis, the functions of the immune system, as well as glucose homeostasis and lipid metabolism, among others. Mounting evidence from animal and human studies indicates that the composition and metabolic profiles of the gut microbiota are linked to the pathogenesis of cardiovascular disease, particularly arterial hypertension, atherosclerosis, and heart failure. In this review article, we provide an overview of the function of the human gut microbiota, summarize, and critically address the evidence linking compositional and functional alterations of the gut microbiota with atherosclerosis and coronary artery disease and discuss the potential of strategies for therapeutically targeting the gut microbiota through various interventions.

Diet-Related and Gut-Derived Metabolites and Health Outcomes: A Scoping Review

We conducted a scoping review to map available evidence about the health impact of gut microbiota-derived metabolites. We searched PubMed and Embase for studies that assessed the health impact of ten metabolites on any health condition: deoxycholate or deoxycholic acid (DCA), lithocholate or lithocholic acid (LCA), glycolithocholate or glycolithocholic acid, glycodeoxycholate or glycodeoxycholic acid, tryptamine, putrescine, d-alanine, urolithins, N-acetylmannosamine, and phenylacetylglutamine. We identified 352 eligible studies with 168,072 participants. Most (326, 92.6%) were case-control studies, followed by cohort studies (14, 4.0%), clinical trials (8, 2.3%), and cross-sectional studies (6, 1.7%). Most studies assessed the following associations: DCA on hepatobiliary disorders (64 studies, 7976 participants), colorectal cancer (19 studies, 7461 participants), and other digestive disorders (27 studies, 2463 participants); LCA on hepatobiliary disorders (34 studies, 4297 participants), colorectal cancers (14 studies, 4955 participants), and other digestive disorders (26 studies, 2117 participants); putrescine on colorectal cancers (16 studies, 94,399 participants) and cancers excluding colorectal and hepatobiliary cancers (42 studies, 4250 participants). There is a need to conduct more prospective studies, including clinical trials. Moreover, we identified metabolites and conditions for which systemic reviews are warranted to characterize the direction and magnitude of metabolite-disease associations.

Association between trimethylamine N-oxide and prognosis of patients with acute myocardial infarction and heart failure

AIMS

This study aimed to investigate the association between trimethylamine N-oxide (TMAO) and the prognosis and association between high-sensitivity C-reactive protein (hsCRP) and TMAO-associated cardiovascular risk in patients with acute myocardial infarction (AMI) complicated by heart failure (HF).

METHODS AND RESULTS

A total of 985 patients presenting with AMI and HF were consecutively enrolled at the Fuwai Hospital between March 2017 and January 2020. Patients were stratified into groups according to tertiles of TMAO levels and the median hsCRP levels. The primary endpoint was major adverse cardiac events (MACE), including all-cause death, recurrence of myocardial infarction, and rehospitalization due to HF. During a median follow-up of 716 days, 138 (14.0%) patients experienced MACE. Cox regression analyses showed that the adjusted hazard ratio (HR) for MACE was higher in patients in tertile 3 [TMAO > 9.52 μmol/L, HR: 1.85, 95% confidence interval (CI): 1.18-2.89; P = 0.007] than in tertile 1 (TMAO < 4.74 μmol/L), whereas no significant differences were detected between the patients in tertiles 1 and 2 (TMAO = 4.74-9.52 μmol/L, HR: 0.96, 95% CI: 0.59-1.58; P = 0.874). Restricted cubic spline regression depicted an S-shaped association between TMAO and MACE (P for nonlinearity = 0.012). In the setting of hsCRP above the median level (6.68 mg/L), per unit increase of TMAO was associated with a 20% increase of MACE risk (HR: 1.20, 95% CI: 1.05-1.37, P = 0.009); increasing tertiles of TMAO were significantly associated with a higher risk of MACE (adjusted P = 0.007 for interaction; P < 0.001 for trend across tertiles). The Kaplan-Meier analysis indicated that patients in tertile 3 had a significantly lower event-free survival (P = 0.001) when the hsCRP level was above the median level. No similar association between TMAO and MACE was observed when the hsCRP level was below the median level.

CONCLUSIONS

High plasma TMAO levels were independently correlated with poor prognosis in patients with AMI complicated by HF, especially in those with higher hsCRP levels. There was an S-shaped relationship between TMAO and HR for MACE.

The Role of Gut Microbiota in Heart Failure: When Friends Become Enemies

Heart failure is a complex health issue, with important consequences on the overall wellbeing of patients. It can occur both in acute and chronic forms and, in the latter, the immune system appears to play an important role in the pathogenesis of the disease. In particular, in the forms with preserved ejection fraction or with only mildly reduced ejection fraction, some specific associations with chronic inflammatory diseases have been observed. Another interesting aspect that is worth considering is the role of microbiota modulation, in this context: given the importance of microbiota in the modulation of immune responses, it is possible that changes in its composition may somewhat influence the progression and even the pathogenesis of heart failure. In this narrative review, we aim to examine the relationship between immunity and heart failure, with a special focus on the role of microbiota in this pathological condition.

The association between heart failure and risk of fractures: Pool analysis comprising 260,410 participants

Background

HF and osteoporosis shared many common etiological risk factors. However, studies exploring whether patients with HF were associated with a higher risk of osteoporotic fracture resulted in inconsistent findings. This meta-analysis aimed to summarize the association between HF and the risk of incident fracture.

Methods

Following the Meta-analysis of Observational Studies in Epidemiology group recommendations, we searched multiple electronic databases (PubMed, Cochran Library, and EMBASE) for related studies from inception to April 30, 2021. Studies evaluating the risk of incident fracture in patients with HF compared with those without HF were included for analysis. The random-effects models were used to combine the estimated hazard ratios (HRs) of incident fracture associated with HF.

Results

We included 8 observational studies for meta-analysis. The sample size ranged from 5,613 to 87,748 participants, with a total of 260,410 participants included. The median follow-up duration was 5.0 years. Random-effects model analyses showed that compared with control groups, patients with HF were associated with a higher risk of all incident fractures (HR = 1.67, 95% CI = 1.30–2.16, P < 0.001) and hip fracture (HR = 2.20, 95% CI = 1.28–3.77, P < 0.001). The risk of all incident fractures was increased in all subgroup analyses according to age, sample size, sex, and follow-up duration.

Conclusions

Patients with HF were associated with a higher risk of incident fracture, as well as hip fracture.

A retrospective cohort study on the association between early coagulation disorder and short-term all-cause mortality of critically ill patients with congestive heart failure

Purpose

Coagulation disorder in congestive heart failure (CHF) has been well-documented. The prognostic value of a composite coagulation disorder score, which combines the absolute platelet count, international normalized ratio (INR), and activated partial thromboplastin time (APTT), has not been assessed in CHF. The present study endeavored to explore the association between the coagulation disorder score and adverse outcomes of critically ill patients with CHF.

Methods

Patients diagnosed with CHF in the Medical Information Mart for Intensive Care III (MIMIC-III) database were included in the present retrospective cohort study. The coagulation disorder score was calculated according to the abnormalities of the absolute platelet count, INR, and APTT within 24 h after intensive care unit admission. The primary outcomes were the short-term all-cause mortality, including 30-, 90-day and in-hospital mortalities. The Kaplan-Meier (K-M) survival curve and the Cox proportional hazard model were performed to assess the correlation between coagulation disorder score and outcome events.

Results

A total of 6,895 patients were enrolled in this study and divided into four groups according to the coagulation disorder score. K-M survival curve preliminarily indicated that subjects with higher coagulation disorder score presented lower survival rate and shorter survival time. After adjustment for potential confounders, the multivariate Cox analysis further illustrated that elevated coagulation disorder score as a quartile variable was significantly associated with increased all-cause mortality (quartile 4 vs. quartile 1, 30-day: HR [95% CI], 1.98 [1.50, 2.62], 90-day: HR [95% CI], 1.88 [1.49, 2.37], in-hospital: HR [95%CI], 1.93 [1.42, 2.61]).

Conclusion

In critically ill patients with CHF, ones with high coagulation disorder score tend to be worse clinical prognosis, which would be a promising biomarker and helpful for the management of CHF patients.

Gastrointestinal Microbiome and Multiple Health Outcomes: Umbrella Review

In recent years, there has been growing concern about the impact of the gastrointestinal microbiome on human health outcomes. To clarify the evidence for a link between the gastrointestinal microbiome and a variety of health outcomes in humans, we conducted an all-encompassing review of meta-analyses and systematic reviews that included 195 meta-analyses containing 950 unique health outcomes. The gastrointestinal microbiome is related to mortality, gastrointestinal disease, immune and metabolic outcomes, neurological and psychiatric outcomes, maternal and infant outcomes, and other outcomes. Existing interventions for intestinal microbiota (such as probiotics, fecal microbiota transplant, etc.) are generally safe and beneficial to a variety of human health outcomes, but the quality of evidence is not high, and more detailed and well-designed randomized controlled trials are necessary.

Association between non-alcoholic fatty liver disease and risk of incident heart failure: a meta-analysis of observational studies

BACKGROUND AND AIMS

Recent research has associated non-alcoholic fatty liver disease (NAFLD) with an increased risk of atherosclerotic cardiovascular disease. Previous studies that evaluated the association between NAFLD and risk of heart failure (HF) yielded inconsistent results, however. This meta-analysis aimed to evaluate the association between NAFLD and the risk of HF.

METHODS

We searched multiple electronic databases, including PubMed, Google Scholar, Embase and Web of Science for potential studies published from inception until 30 October 2021. Cohort studies reported multivariable-adjusted risks of incident HF in NAFLD patients comparing those without NAFLD were included.

RESULTS

Six cohort studies comprising 10,979,967 participants (women = 55.5%) were included in the study. The median prevalence of NAFLD in these studies was 22.2%. During a median follow-up duration of 7.0 years, 92,915 HF cases were detected. In the unadjusted model, patients with NAFLD had a greater risk of incident HF [random-effect hazard ratio (HR) = 1.47, 95% confidence interval (CI) = 1.25-1.75, I 2 = 99%], compared with those without NAFLD. After multivariable adjustment of confounding risk factors, NAFLD was still linked with a higher risk of HF incidence (random-effect HR = 1.36, 95% CI = 1.16-1.58, I 2 = 98%). The risk of HF was increased not only in patients with progressive NAFLD severity but also in those with simple steatosis. The absolute risk difference of HF in NAFLD patients compared with those without NAFLD was 11.0 (95% CI = 4.9-17.7) per 10,000 person-years after multivariable adjustment.

CONCLUSION

This meta-analysis suggests that NAFLD may be associated with an increased risk of incident HF. Owing to the high heterogeneity of the published studies, however, further high-quality studies are still needed.

The controlling nutritional status score and clinical outcomes in patients with heart failure: Pool analysis of observational studies

Background and aims

Malnutrition is very common in patients with heart failure (HF) and is associated with a worse clinical outcome. The Controlling Nutritional Status (CONUT) score is an easily derived index for the evaluation of malnutrition. This study aimed to evaluate the association between the CONUT score and the prognosis in patients with HF.

Methods and results

Electronic databases were searched for potential studies from inception up to February 15, 2022. Observational cohort studies included adult participants with HF, and reported the associations between the CONUT score and the adjusted relative risk (RR) of all-cause mortality, and patients with composite major adverse cardiac outcomes (MACEs) were included. We finally included 18 studies comprising 12,532 participants with HF for analysis. The median age of the patients was 70.5 years old, and 35.4% were women. After a median follow-up duration of 32.5 months, patients with HF with a higher CONUT score were associated with a higher risk of all-cause mortality (per 1 increment of the CONUT score: RR, 1.21, 95% CI, 1.13–1.29, I² = 68%, P for heterogeneity = 0.002) and MACEs (per 1 increment of the CONUT score: RR, 1.14, 95% CI, 1.06–1.23, I² = 81%, P for heterogeneity <0.0001) after adjusting for other prognostic factors. When the CONUT score was divided into the normal nutritional status and malnourished status, malnourished patients with HF were associated with increased risks of all-cause death (RR, 1.61, 95% CI, 1.40–1.85, I² = 17%, P for heterogeneity = 0.29) and MACEs (RR, 2.12, 95% CI, 1.49–3.02, I² = 87%, P for heterogeneity <0.0001), compared with those with normal nutritional status.

Conclusions

The CONUT score is associated with the clinical outcomes in patients with HF, and can be used as a screening tool of nutritional status in HF to improve prognosis.

Development of Prediction Model to Estimate the Risk of Heart Failure in Diabetes Mellitus

Background

Heart failure (HF) is a leading cause of mortality and disability in patients with diabetes mellitus (DM). The aim of the study is to predict the risk of HF incidence in patients with DM by developing a risk prediction model.

Methods

We constructed a regression model based on 270 inpatients with DM between February 2018 and January 2019. Binary logistic regression was applied to develop the final model incorporating the predictors selected by least absolute shrinkage and selection operator regression. The nomogram was estimated with an area under the receiver operator characteristic curve and calibration diagram and validated with the bootstrap method.

Results

Risk factors including age, coronary heart disease (CHD), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) were incorporated in the final model as predictors. Age ≥ 61 years old, LDL, and CHD were risk factors for DM with HF, with odds ratios (ORs) of 32.84 (95% CI: 6.74, 253.99), 1.33 (95% CI: 1.06, 1.72), and 3.94 (95% CI: 1.43, 13.43), respectively. HDL was a protective factor with an OR of 0.11 (95% CI: 0.04, 0.28). The area under curve of the model was 0.863 (95% confidence interval, 0.812∼0.913). The plot of the calibration showed that there was a good consistency between predicted probability and actual probability. Harrell’s C-index of the nomogram was 0.845, and the model showed satisfactory calibration in the internal validation cohort.

Conclusion

The prediction nomogram we developed can estimate the possibility of HF in patients with DM according the predictor items.

Gut microbiota-derived metabolite trimethylamine-N-oxide and multiple health outcomes: an umbrella review and updated meta-analysis

BACKGROUND

Trimethylamine-N-oxide (TMAO) is a gut microbiota-derived metabolite produced from dietary nutrients. Many studies have discovered that circulating TMAO concentrations are linked to a wide range of health outcomes.

OBJECTIVES

This study aimed to summarize health outcomes related to circulating TMAO concentrations.

METHODS

We searched the Embase, Medline, Web of Science, and Scopus databases from inception to 15 February, 2022 to identify and update meta-analyses examining the associations between TMAO and multiple health outcomes. For each health outcome, we estimated the summary effect size, 95% prediction CI, between-study heterogeneity, evidence of small-study effects, and evidence of excess-significance bias. These metrics were used to evaluate the evidence credibility of the identified associations.

RESULTS

This umbrella review identified 24 meta-analyses that investigated the association between circulating TMAO concentrations and health outcomes including all-cause mortality, cardiovascular diseases (CVDs), diabetes mellitus (DM), cancer, and renal function. We updated these meta-analyses by including a total of 82 individual studies on 18 unique health outcomes. Among them, 14 associations were nominally significant. After evidence credibility assessment, we found 6 (33%) associations (i.e., all-cause mortality, CVD mortality, major adverse cardiovascular events, hypertension, DM, and glomerular filtration rate) to present highly suggestive evidence.

CONCLUSIONS

TMAO might be a novel biomarker related to human health conditions including all-cause mortality, hypertension, CVD, DM, cancer, and kidney function. Further studies are needed to investigate whether circulating TMAO concentrations could be an intervention target for chronic disease.This review was registered at www.crd.york.ac.uk/prospero/ as CRD42021284730.

The Relationship Between Atrial Fibrillation and Intestinal Flora With Its Metabolites

Atrial fibrillation (AF) is characterized by high morbidity and disability rate. The incidence of AF has rapidly increased due to increased aging population, causing a serious burden on society and patients. Therefore, it is necessary to determine the prevention and treatment of AF. Several studies have assessed the occurrence, development mechanism, and intervention measures of AF. The human gut has several non-pathogenic microorganisms forming the gut flora. The human gut microbiota plays a crucial role in the construction and operation of the metabolic system and immune system. Emerging clinical studies and basic experiments have confirmed that intestinal flora and its metabolites have a role in some metabolic disorders and chronic inflammatory diseases. Moreover, the gut microbiota has a role in cardiovascular diseases, such as hypertension and heart failure. However, the relationship between AF and gut microbiota is unclear. This review summarizes the relevant literature on the relationship between AF and intestinal flora with its metabolites, including Trimethylamine N-Oxide, short-chain fatty acids, lipopolysaccharide and bile acids. Therefore, this review may enhance further development of related research.

Biomarkers of Oxidative Stress Tethered to Cardiovascular Diseases

Cardiovascular disease (CVD) is a broad term that incorporated a group of conditions that affect the blood vessels and the heart. CVD is a foremost cause of fatalities around the world. Multiple pathophysiological mechanisms are involved in CVD; however, oxidative stress plays a vital role in generating reactive oxygen species (ROS). Oxidative stress occurs when the concentration of oxidants exceeds the potency of antioxidants within the body while producing reactive nitrogen species (RNS). ROS generated by oxidative stress disrupts cell signaling, DNA damage, lipids, and proteins, thereby resulting in inflammation and apoptosis. Mitochondria is the primary source of ROS production within cells. Increased ROS production reduces nitric oxide (NO) bioavailability, which elevates vasoconstriction within the arteries and contributes to the development of hypertension. ROS production has also been linked to the development of atherosclerotic plaque. Antioxidants can decrease oxidative stress in the body; however, various therapeutic drugs have been designed to treat oxidative stress damage due to CVD. The present review provides a detailed narrative of the oxidative stress and ROS generation with a primary focus on the oxidative stress biomarker and its association with CVD. We have also discussed the complex relationship between inflammation and endothelial dysfunction in CVD as well as oxidative stress-induced obesity in CVD. Finally, we discussed the role of antioxidants in reducing oxidative stress in CVD.

The heart and gut relationship: a systematic review of the evaluation of the microbiome and trimethylamine-N-oxide (TMAO) in heart failure

There is an expanding body of research on the bidirectional relationship of the human gut microbiome and cardiovascular disease, including heart failure (HF). Researchers are examining the microbiome and gut metabolites, primarily trimethylamine-N-oxide (TMAO), to understand clinically observed outcomes. This systematic review explored the current state of the science on the evaluation and testing of the gut biome in persons with HF. Using electronic search methods of Medline, Embase, CINAHL, and Web of Science, until December 2021, we identified 511 HF biome investigations between 2014 and 2021. Of the 30 studies included in the review, six were 16S rRNA and nineteen TMAO, and three both TMAO and 16S rRNA, and two bacterial cultures. A limited range of study designs were represented, the majority involving single cohorts (n = 10) and comparing individuals with HF to controls (n = 15). Patients with HF had less biodiversity in fecal samples compared to controls. TMAO is associated with age, BNP, eGFR, HF severity, and poor outcomes including hospitalizations and mortality. Inconsistent across studies was the ability of TMAO to predict HF development, the independent prognostic value of TMAO when controlling for renal indices, and the relationship of TMAO to LVEF and CRP. Gut microbiome dysbiosis is associated with HF diagnosis, disease severity, and prognostication related to hospitalizations and mortality. Gut microbiome research in patients with HF is developing. Further longitudinal and multi-centered studies are required to inform interventions to promote clinical decision-making and improved patient outcomes.

Association Between Prognostic Nutritional Index and Prognosis in Patients With Heart Failure: A Meta-Analysis

Background

The prognostic nutritional index (PNI) has been proposed as a marker of malnutrition and associated with the prognosis of cardiovascular disease. However, whether PNI can serve as a potential biomarker for the prognosis of heart failure (HF) upon those established risk factors were still controversial. This meta-analysis aimed to generate comprehensive evidence on the prognostic value of PNI in patients with HF.

Methods

Multiple databases (PubMed, Embase, the Cochrane Library, and Google Scholar) were searched for related studies up to January 31, 2022. Observational studies accessed associations between PNI levels and the prognosis in patients with HF were included for meta-analysis. The hazard ratios (HRs) and 95% confidence intervals (CI) were calculated.

Results

Fourteen studies, comprising 19,605 patients with HF were included for meta-analysis. The median follow-up duration was 18.5 months. Compared with those with higher PNI (normal nutritional status), patients with HF with lower PNI (malnourished) were associated with a higher risk of all-cause mortality (HR 1.53, 95% CI 1.27–1.85) and composite major adverse cardiac outcomes (MACEs; HR 2.26, 95% CI 1.54–3.31) in the multivariable-adjusted model. Furthermore, when PNI was defined as per 1 increment as a continuous metric, higher PNI was associated with a decrease in all-cause mortality (per 1 increment of PNI: HR 0.94, 95% CI 0.88–0.96) and MACEs (per 1 increment of PNI: HR 0.97, 95% CI 0.95–0.98).

Conclusions

The PNI can serve as an easily calculated bedside “malnutrition-inflammation” biomarker in HF. Lower PNI was associated with a worse prognosis in patients with HF.

Nutritional biomarkers and heart failure requiring hospitalization in patients with type 2 diabetes: the SURDIAGENE cohort

Background

Heart failure (HF) is a growing complication and one of the leading causes of mortality in people living with type 2 diabetes (T2D). Among the possible causes, the excess of red meat and the insufficiency of vegetables consumption are suspected. Such an alimentation is associated with nutritional biomarkers, including trimethylamine N-oxide (TMAO) and its precursors. Here, we aimed to study these biomarkers as potential prognostic factors for HF in patients with T2D.

Methods

We used the SURDIAGENE (SURvival DIAbetes and GENEtics) study, a large, prospective, monocentric cohort study including 1468 patients with T2D between 2001 and 2012. TMAO and its precursors (trimethylamine [TMA], betaine, choline, and carnitine) as well as thio-amino-acids (cysteine, homocysteine and methionine) were measured by liquid chromatography-tandem mass spectrometry. The main outcome was HF requiring Hospitalization (HFrH) defined as the first occurrence of acute HF leading to hospitalization and/or death, established by an adjudication committee, based on hospital records until 31st December 2015. The secondary outcomes were the composite event HFrH and/or cardiovascular death and all-cause death. The association between the biomarkers and the outcomes was studied using cause-specific hazard-models, adjusted for age, sex, history of coronary artery disease, NT-proBNP, CKD-EPI-derived eGFR and the urine albumin/creatinine ratio. Hazard-ratios (HR) are expressed for one standard deviation.

Results

The data of interest were available for 1349/1468 of SURDIAGENE participants (91.9%), including 569 (42.2%) women, with a mean age of 64.3 ± 10.7 years and a median follow-up of 7.3 years [25th–75th percentile, 4.7–10.8]. HFrH was reported in 209 patients (15.5%), HFrH and/or cardiovascular death in 341 (25.3%) and all-cause death in 447 (33.1%). In unadjusted hazard-models, carnitine (HR = 1.20, 95% CI [1.05; 1.37]), betaine (HR = 1.34, [1.20; 1.50]), choline (HR = 1.35, [1.20; 1.52]), TMAO (HR = 1.32, [1.16; 1.50]), cysteine (HR = 1.38, [1.21; 1.58]) and homocysteine (HR = 1.28, [1.17; 1.39]) were associated with HFrH, but not TMA and methionine. In the fully adjusted models, none of these associations was significant, neither for HFrH nor for HFrH and/or CV death, when homocysteine only was positively associated with all-cause death (HR = 1.16, [1.06; 1.27]).

Conclusions

TMAO and its precursors do not appear to be substantial prognosis factors for HFrH, beyond usual cardiac- and kidney-related risk factors, whereas homocysteine is an independent risk factor for all-cause death in patients with T2D.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01505-9.

Association Between Dietary Fiber Intake and Heart Failure Among Adults: National Health and Nutrition Examination Survey 2009–2018

Objective

To explore the association between dietary fiber and heart failure (HF).

Methods

Data were collected from the 2009–2018 National Health and Nutrition Examination Survey. Dietary fiber intake data were obtained from two 24-h dietary recall interviews. Logistic regression and restricted cubic spline models were used to explore the association of dietary intakes of total, cereal, fruit, and vegetable fiber with HF prevalence.

Results

A total of 21869 adults were included in this study. After adjusting for multiple confounding factors, the odds ratios (OR) and 95% confidence intervals (CI) for HF was 0.49 (0.28 to 0.87, P for trend = 0.016) for the highest tertile versus lowest tertile of total fiber intake. Similar results were observed for cereal but not fruit and vegetable fiber intake. Dose-response analysis indicated that dietary intake of total and cereal fiber were inversely associated with HF in a linear manner.

Conclusion

Intakes of total and cereal fiber were inversely associated with HF in adults.

Associations between the gut microbiome, gut microbiology and heart failure: Current understanding and future directions

The role of the gut microbiome in pathophysiology, prognostication and clinical management of heart failure (HF) patients is of great clinical and research interest. Both preclinical and clinical studies have shown promising results, and the gut microbiome has been implicated in other cardiovascular conditions that are risk factors for HF. There is an increasing interest in the use of biological compounds produced as biomarkers for prognostication as well as exploration of therapeutic options targeting the various markers and pathways from the gut microbiome that are implicated in HF. However, study variations exist, and targeted research for individual putative biomarkers is necessary. There is also limited evidence pertaining to decompensated HF in particular. In this review, we synthesize current understandings around pathophysiology, prognostication and clinical management of heart failure (HF) patients, and also provide an outline of potential areas of future research and scientific advances.

Knowledge Mapping of the Links Between the Gut Microbiota and Heart Failure: A Scientometric Investigation (2006–2021)

Background

There is considerable research value and extensive application perspectives to explore the link between gut microbiota and heart failure. The purpose of this study is to provide an overview of overall characteristics, evolutionary pathways, frontier research hotspots, and future trends in this field.

Methods

Research datasets were acquired from the Web of Science Core Collection (WoSCC) between January 1, 2006 and December 31, 2021. Three different analysis tools including one online platform, VOS viewer V1.6.17.0, and CiteSpace V5.8.R2 software were used in order to conduct collaboration network analysis, co-cited analysis, co-occurring analysis, and citation burst detection.

Results

A total of 873 publications in the WoSCC database met the requirement. The overall characteristics analysis showed that a steady growth trend in the number of publications and citations, with the predominant literature type being articles and the most frequent subject category being cardiac cardiovascular systems. The United States was the most prolific country and the center of national collaboration. Cleveland Clinic and Nathalie M. Delzenne provided the leading influence with publications, the cooperation between the institutes and authors were relatively weak. Moreover, gut microbiota, heart failure, risk factor, obesity, and inflammation were the keywords that appeared more frequently in the clustering analysis of reference co-citation and keyword co-occurrence. Burst detection analysis of top keywords showed that trimethylamine N-oxide (TMAO), bile acid, blood pressure, hypertension, and fermentation were the new research foci on the association between gut microbiota and heart failure. Strategies to improve gut microbiota hold promise as a new approach to treat heart failure.

Conclusion

The comprehensive bibliometric study indicates that the structured information may be helpful in understanding research trends in the link between gut microbiota and heart failure, and locating research hotspots and gaps in this domain, especially further advances in this field will lead to significant breakthroughs in the development of novel therapeutic tools for metabolic modulation of heart failure.

Long-chain omega-3 polyunsaturated fatty acids and the risk of heart failure

AIMS

Adequate intake of long-chain (LC) omega-3 polyunsaturated fatty acids (n-3 PUFAs) is considered important for cardiovascular health. However, the effects of LC n-3 PUFAs on the risk of heart failure (HF) remain unclear. This systematic review and meta-analysis aimed to determine the role of LC n-3 PUFAs in the incidence of HF.

MATERIALS AND METHODS

Electronic databases were searched for studies up to 31 July 2021. Studies were included for the meta-analysis if they reported the adjusted associations between different dietary intakes or circulating concentrations of LC n-3 PUFAs and the risk of HF. A random-effect model was used to calculate the pooled estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for higher LC n-3 PUFA concentrations.

RESULTS

Thirteen studies were included in the meta-analysis. Eight studies comprising 316,698 individuals (11,244 incident HF cases), with a median follow-up of 10.7 years, showed that a higher dietary intake of LC n-3 PUFAs was associated with a lower risk of HF (highest versus lowest quintile: HR = 0.84, 95% CI = 0.75-0.94). Six studies, comprising 17,163 participants (2520 HF cases) with a median follow-up of 9.7 years, showed that higher circulating LC n-3 PUFA concentrations were associated with a lower risk of HF (highest versus lowest quintile: HR = 0.59, 95% CI = 0.39-0.91). Higher circulating docosahexaenoic acid concentrations were associated with a decreased risk of HF (top versus bottom quintile: HR = 0.44, 95% CI = 0.26-0.77). The associations between eicosapentaenoic acid (HR = 0.58, 95% CI = 0.26-1.25), docosahexaenoic acid (HR = 0.66, 95% CI = 0.24-1.82), and the risk of HF were not significant.

CONCLUSION

High LC n-3 PUFA concentrations measured by dietary intake or circulating biomarkers are associated with a lower risk of developing HF.

Trimethylamine N-Oxide in Heart Failure: A Meta-Analysis of Prognostic Value

Objective

The present study aimed to explore the prognostic value of trimethylamine N-oxide (TMAO) in heart failure (HF).

Methods

PubMed, Excerpta Medica Database (EMBASE), Cochrane Library, Web of Science, Wanfang Database, SINOMED, China Science and Technology Journal Database (VIP), and China National Knowledge Infrastructure (CNKI) were searched up to June 1, 2021. Studies recording the major adverse cardiovascular events (MACEs) or all-cause mortality in HF patients and their circulating TMAO concentrations were included. Meta-analysis was performed using Stata 13.0.

Results

Ten articles (12 studies) involving 13,425 participants from 2014 to 2021 were considered. Compared to low-level TMAO, elevated TMAO was correlated with MACEs and all-cause mortality in HF (RR: 1.28, 95% CI: 1.17, 1.39, P < 0.0001, random-effects model and RR: 1.35, 95% CI: 1.28, 1.42, P < 0.0001, random-effects model, respectively). Consistent results were obtained in all examined subgroups as well as in the sensitivity analysis.

Conclusion

Elevated TMAO may be an adverse prognostic indicator in patients with HF.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=267208

Prognostic Value of β1 Adrenergic Receptor Autoantibody and Soluble Suppression of Tumorigenicity-2 in Patients With Acutely Decompensated Heart Failure

Background

Both β1 adrenergic receptor autoantibody (β1-AA) and soluble suppression of tumorigenicity-2 (sST2) take a role in the pathological remodeling of heart failure. However, limited studies investigated the correlation between the expression of β1-AA and sST2 in patients with acutely decompensated heart failure (ADHF).

Objective

To explore the correlation between β1-AA and sST2, and evaluate their prognostic value in patients with ADHF.

Methods

Patients who were admitted for ADHF were included. The N-terminal pro-brain natriuretic peptide (NT-proBNP), sST2, and β1-AA in blood samples were tested at hospital admission and then followed up for assessing the outcomes. Pearson correlation analysis was used to explore the correlation between β1-AA and sST2. The effects of β1-AA, sST2, or the combination of them on the all-cause mortality of patients with ADHF were assessed by Multivariate Cox regression analysis.

Results

There were 96 patients with ADHF and 96 control populations enrolled. The β1-AA was significantly higher in ADHF than in the control group (0.321 ± 0.06 vs. 0.229 ± 0.04, P = 0.000). Pearson correlation analysis showed that β1-AA was positively correlated with sST2 (r = 0.593), NT-proBNP (r = 0.557), Procalcitonin (r = 0.176), and left ventricular end-diastolic diameter (r = 0.315), but negatively correlated with triglycerides (r = −0.323), and left ventricular ejection fraction (r = −0.430) (all P < 0.05) in ADHF. Patients with ADHF, complicated with both high β1-AA and sST2, showed the highest all-cause mortality during an average of 25.5 months of follow-up. Multivariate Cox regression showed the combination of both high β1-AA and sST2 independently correlated with the all-cause mortality after adjustment for other risk factors (hazard ratio 3.348, 95% CI 1.440 to 7.784, P = 0.005). After adding with β1-AA and sST2, the area under the curves for the prognostic all-cause mortality could increase from 0.642 to 0.748 (P = 0.011).

Conclusion

The β1-AA is positively correlated with sST2 in patients with ADHF. Elevated plasma β1-AA and sST2 level in patients with ADHF are associated with poorer prognoses.

Association Between Serum Galectin-3 Levels and Coronary Stenosis Severity in Patients With Coronary Artery Disease

Background

The relationship between galectin-3 (Gal-3) and coronary artery disease (CAD) has not been fully elucidated.

Aim

This study aimed to determine the relationship between the presence and severity of CAD and serum Gal-3 levels.

Patients and Methods

Three-hundred thirty-one consecutive CAD patients were enrolled as the study group. An additional 62 patients without CAD were enrolled as the control group. Serum Gal-3 levels were separately compared between the non-CAD and CAD groups, among the stable CAD and Acute coronary syndrome (ACS) groups, and between CAD patients with low and high SYNTAX scores (SSs). The 1-year cumulative rate of major adverse cardiac events (MACEs) was also compared among ACS patients by Gal-3 levels.

Results

Serum Gal-3 was significantly higher in the CAD group than in the non-CAD group 3.89 (0.16–63.67) vs. 2.07 (0.23–9.38) ng/ml, P < 0.001. Furthermore, serum Gal-3 was significantly higher in the non-ST-segment elevation ACS (NSTE-ACS) group than that in the stable CAD group, 4.72 (1.0–16.14) vs. 2.23 (0.65–23.8) ng/ml, P = 0.04 and higher in the ST-segment elevation myocardial infarction (STEMI) group than that in the stable CAD group 7.87 (0.59–63.67) vs. 2.23 (0.65–23.8) ng/ml, P < 0.001. Serum Gal-3 level was an independent predictor of ACS compared with stable CAD group (OR = 1.131, 95% CI: 1.051–1.217, P = 0.001) as well as high SS (OR = 1.030, 95% CI: 1.021–1.047, P = 0.038) after adjust other confounding risk factors. Acute coronary syndrome patients with Gal-3 levels above the median (gal-3 = 4.78 ng/ml) showed a higher cumulative MACE rate than those with Gal-3 levels below the median. After adjusting other confounding risk factors, Gal-3 remained an independent risk factor for the cumulative rate of MACEs in ACS patients (6% higher rate of MACEs incidence per 1 ng/ml increment of Gal-3).

Conclusion

Galectin-3 correlated with the presence of CAD as well as coronary stability and complexity. Galectin-3 may be valuable in predicting mid-term prognosis in ACS patients.

Circulating trimethylamine N-oxide levels following fish or seafood consumption

PURPOSE

Some species of fish and seafood are high in trimethylamine N-oxide (TMAO), which accumulates in muscle where it protects against pressure and cold. Trimethylamine (TMA), the metabolic precursor to TMAO, is formed in fish during bacterial spoilage. Fish intake is promoted for its potential cardioprotective effects. However, numerous studies show TMAO has pro-atherothrombotic properties. Here, we determined the effects of fish or seafood consumption on circulating TMAO levels in participants with normal renal function.

METHODS

TMAO and omega-3 fatty acid content were quantified across multiple different fish or seafood species by mass spectrometry. Healthy volunteers (n = 50) were recruited for three studies. Participants in the first study consented to 5 consecutive weekly blood draws and provided dietary recall for the 24 h preceding each draw. In the second study, TMAO levels were determined following defined low and high TMAO diets. Finally, participants consumed test meals containing shrimp, tuna, fish sticks, salmon or cod. TMAO levels were quantified by mass spectrometry in blood collected before and after dietary challenge.

RESULTS

TMAO + TMA content varied widely across fish and seafood species. Consumption of fish sticks, cod, and to a lesser extent salmon led to significant increases in circulating TMAO levels. Within 1 day, circulating TMAO concentrations in all participants returned to baseline levels.

CONCLUSIONS

We conclude that some fish and seafood contain high levels of TMAO, and may induce a transient elevation in TMAO levels in some individuals. Selection of low TMAO content fish is prudent for subjects with elevated TMAO, cardiovascular disease or impaired renal function.

The Nonlinear Relationship Between Total Bilirubin and Coronary Heart Disease: A Dose-Response Meta-Analysis

Background: Evidence suggests that the total bilirubin has a protective effect on coronary heart disease (CHD), but the dose-response relationship remains controversial, and there is no meta-analysis to assess the relationship.

Methods: As of October 1, 2021, relevant literature was selected from four databases (PubMed, Web of Science, Cochrane Library, and Embase) by using a retrieval strategy. The dose-response curve between the total bilirubin and CHD was fitted by a restricted cubic spline. Stata 12.0 was used for statistical analysis.

Results: A total of 170,209 (6,342 cases) participants from 7 prospective studies were analyzed in our meta-analysis. We calculated the pooled relative risks (RRs) and 95% CIs for the association between serum bilirubin level and risk of CHD using random-effects models. Compared with the first quantile, the bilirubin level in the third quantile had a protective effect on the risk of CHD (RR, 0.90; 95% CI, 0.82–0.99). The restricted cubic spline functions depicted a U-type curve relationship between bilirubin (3.42–49 μmol/L) and CHD (P_linear < 0.001). When the bilirubin level was in the range of 3.42–13μmol/L, the protective effect of bilirubin on CHD was enhanced with increasing bilirubin levels. When the bilirubin level exceeded 13μmol/L, the protective effect of bilirubin weakened, and a dangerous effect gradually appeared with further increases in bilirubin levels.

Conclusions: Compared with a low bilirubin level, a high bilirubin level has a protective effect on the risk of CHD, and there was a U-shaped dose-response relationship between them.

α-Linolenic Acid and Risk of Heart Failure: A Meta-Analysis

Background: The α-linolenic acid is a plant origin n-3 fatty acid that may reduce the risk of cardiovascular disease. However, the effect of α-linolenic acid (ALA) on the risk of heart failure (HF) remains unclear. In this meta-analysis, we aimed to determine the role of ALA in the risk of incident HF. Methods: Electronic databases were searched for studies up to August 10, 2021. Studies were included for meta-analysis if the adjusted risk of HF in different dietary intake or circulating levels of ALA was reported. We used the random-effects model to calculate the estimated hazard ratios (HRs) and 95% CI for higher ALA. Results: A total of 6 studies (7 cohorts) comprising 135,270 participants were included for meta-analysis. After a median follow-up duration of 10 years, 5,905 cases of HF were recorded. No significant heterogeneity was observed among all the included studies. Random-effects model analyses showed that there was no significant association between ALA and the risk of incident HF, either assessed as quintiles (highest quintile vs. lowest quintile: HR = 0.95, 95% CI = 0.86-1.06) or per 1 SD increment (HR = 0.99, 95% CI = 0.95-1.01). Furthermore, we did not observe any association between ALA and the risk of HF in subgroup analyses performed according to age, sex, follow-up duration, and measuring method of ALA. Conclusions: We found no association between ALA and the risk of incident HF, suggesting that ALA might not be effective in the prevention of HF.

Spermidine Affects Cardiac Function in Heart Failure Mice by Influencing the Gut Microbiota and Cardiac Galectin-3

Spermidine, which can be synthesized by the gut microbiota, can prevent cardiac hypertrophy and delay the progression to heart failure (HF). However, it is not clear whether the effect of spermidine on cardiac function is mediated by modulating the gut microbiota when HF occurs. Female HF Kunming mice induced by transverse aortic constriction were administered spermidine (HF+S group) or its antagonist (HF+SR group). Echocardiography, messenger ribonucleic acid (RNA) and protein expression of galectin-3 in the heart, cardiomyocyte apoptosis assays and gut microbiota analysis were detected. Left ventricular end-diastolic volume and diameter (LVVd and LVDd), and left ventricular end-systolic volume and diameter in the HF+SR group were significantly enlarged compared with those in the HF group (all P < 0.05). The HF+S group had a smaller LVDd and LVVd than the HF+SR group (5.01 ± 0.67 vs. 6.13 ± 0.45 mm, P = 0.033; 121.44 ± 38.74 vs. 189.94 ± 31.42 μL, P = 0.033). The messenger RNA and protein expression of galectin-3 and the number of apoptotic cardiomyocytes increased significantly in the HF+SR group compared to the HF group. Gut microbiota analysis showed that spermidine antagonists reduced the Firmicutes/Bacteroidetes ratio and changed the microbial community richness and diversity. In conclusion, spermidine can improve cardiac function in HF, and the regulation of gut microbiota and cardiac fibrosis may be a factor in the effect of spermidine on the improvement of cardiac function.

The Nutritional Supplement L-Alpha Glycerylphosphorylcholine Promotes Atherosclerosis

L-alpha glycerylphosphorylcholine (GPC), a nutritional supplement, has been demonstrated to improve neurological function. However, a new study suggests that GPC supplementation increases incident stroke risk thus its potential adverse effects warrant further investigation. Here we show that GPC promotes atherosclerosis in hyperlipidemic Apoe-/- mice. GPC can be metabolized to trimethylamine N-oxide, a pro-atherogenic agent, suggesting a potential molecular mechanism underlying the observed atherosclerosis progression. GPC supplementation shifted the gut microbial community structure, characterized by increased abundance of Parabacteroides, Ruminococcus, and Bacteroides and decreased abundance of Akkermansia, Lactobacillus, and Roseburia, as determined by 16S rRNA gene sequencing. These data are consistent with a reduction in fecal and cecal short chain fatty acids in GPC-fed mice. Additionally, we found that GPC supplementation led to an increased relative abundance of choline trimethylamine lyase (cutC)-encoding bacteria via qPCR. Interrogation of host inflammatory signaling showed that GPC supplementation increased expression of the proinflammatory effectors CXCL13 and TIMP-1 and activated NF-κB and MAPK signaling pathways in human coronary artery endothelial cells. Finally, targeted and untargeted metabolomic analysis of murine plasma revealed additional metabolites associated with GPC supplementation and atherosclerosis. In summary, our results show GPC promotes atherosclerosis through multiple mechanisms and that caution should be applied when using GPC as a nutritional supplement.

Association of Systemic Immune-Inflammation Index With Short-Term Mortality of Congestive Heart Failure: A Retrospective Cohort Study

Purpose: The present study aimed to clarify the potential predictive significance of Systemic immune-inflammation index (SII) in assessing the poor prognosis of critically ill patients with congestive heart failure (CHF). Methods: Detailed clinical data were extracted from the Multiparameter Intelligent Monitoring in Intensive Care III database after gaining access and building the local platform. The 30- and 90-day and hospital all-cause mortalities of the patient was the primary outcome, and the readmission rate and the occurrence of major cardiovascular adverse events (MACEs) were the secondary outcomes. the Cox proportional hazard model and Logistic regression analysis were selected to reveal the relationship between SII level and the research outcome. Further, the propensity score matching (PSM) analysis was performed to improve the reliability of results by reducing the imbalance across groups. Results: There were a total of 4,606 subjects who passed the screening process and entered the subsequent analysis. Multivariate regression analysis showed that after adjusting for possible confounders, including age, heart rate, and albumin, etc., the high level of SII was independently associated with 30- and 90-day and hospital mortalities (tertile 3 vs. tertile 1: HR, 95% CIs: 1.23, 1.04-1.45; 1.21, 1.06-1.39; 1.26, 1.05-1.50) and the incidence of MACEs (tertile 3 vs. tertile 1: OR, 95% CI: 1.39, 1.12-1.73) in critically ill patients with CHF, but no significant correlation was found between SII and the readmission rate. Consistently, patients with high SII level still presented a significantly higher short-term mortality than patients with low SII in the PSM subset. Conclusion: In critically ill patients with CHF, high level of SII could effectively predict high 30- and 90-day and hospital mortalities, as well as the high risk of occurrence of MACEs.

Interplay Between Gut Microbiota and Amino Acid Metabolism in Heart Failure

Heart failure (HF) is a complex clinical syndrome of which the incidence is on the rise worldwide. Cardiometabolic disorders are associated with the deterioration of cardiac function and progression of HF. Recently, there has been renewed interest in gut microbiota (GM) and its metabolites in the cardiovascular disease. HF-caused hypoperfusion could increase intestinal permeability, and a “leaky” bowel leads to bacterial translocation and make its metabolites more easily enter the circulation. Considerable evidence shows that the composition of microbiota and amino acids (AAs) has been altered in HF patients, and AAs could serve as a diagnostic and prognostic biomarker in HF. The findings indicate that the gut–amino acid–HF axis may play a key role in the progression of HF. In this paper, we focus on the interrelationship between the AA metabolism and GM alterations during the development of heart failure. We also discuss the potential prognostic and therapeutic value of the gut–amino acid–HF axis in the cortex of HF.

Heart failure in type 2 diabetes: current perspectives on screening, diagnosis and management

Type 2 diabetes is one of the most relevant risk factors for heart failure, the prevalence of which is increasing worldwide. The aim of the review is to highlight the current perspectives of the pathophysiology of heart failure as it pertains to type 2 diabetes. This review summarizes the proposed mechanistic bases, explaining the myocardial damage induced by diabetes-related stressors and other risk factors, i.e., cardiomyopathy in type 2 diabetes. We highlight the complex pathology of individuals with type 2 diabetes, including the relationship with chronic kidney disease, metabolic alterations, and heart failure. We also discuss the current criteria used for heart failure diagnosis and the gold standard screening tools for individuals with type 2 diabetes. Currently approved pharmacological therapies with primary use in type 2 diabetes and heart failure, and the treatment-guiding role of NT-proBNP are also presented. Finally, the influence of the presence of type 2 diabetes as well as heart failure on COVID-19 severity is briefly discussed.

Dietary Intake and Biomarkers of α-Linolenic Acid and Mortality: A Meta-Analysis of Prospective Cohort Studies

Background: The association between α-linolenic acid (ALA) and mortality is inconsistent and has not been summarized systematically. Objective: The purpose was to conduct a meta-analysis that synthesized the results of prospective cohort studies to investigate associations between ALA intake and mortality. Methods: We conducted a comprehensive search on PubMed, Embase, and Web of Science databases on May 1, 2021, for relevant prospective cohort studies which reported associations of ALA (assessed by dietary surveys and/or ALA concentrations in body tissues) with mortality from all-cause, cardiovascular disease (CVD), and other diseases. Multivariable-adjusted relative risks (RRs) were pooled by a random or fixed-effects model. Results: A total of 34 prospective cohort studies, of which 17 reported dietary ALA intake, 14 for ALA biomarkers, and the remaining 3 reported both of intake and biomarkers. The studies included 6,58,634 participants, and deaths were classified into all-cause mortality (56,898), CVD mortality (19,123), and other diseases mortality (19,061). Pooled RRs of ALA intake were 0.93 (95% CI: 0.86, 1.01, I 2 = 71.2%) for all-cause mortality, 0.90 (95% CI: 0.83, 0.98, I 2 = 22.1%) for CVD mortality, and 0.94 (95% CI: 0.83, 1.06, I 2 = 73.3%) for other diseases mortality. The two-stage random-effects dose-response analysis showed a linear relationship between dietary ALA intake and CVD-mortality and each 0.5% energy increment of ALA intake was associated with a 5% lower risk of CVD-mortality (RR: 0.95; 95% CI: 0.90, 1.00). Pooled RRs per SD increment of ALA biomarkers were 0.99 (95% CI: 0.96, 1.01, I 2 = 27%) for all-cause mortality, 1.00 (95% CI: 0.98, 1.03, I 2 = 0%) for CVD mortality and 0.98 (95% CI: 0.95, 1.01, I 2 = 0%) for other diseases mortality. Conclusions: This meta-analysis summarizing the available prospective cohort studies indicated that ALA intake was associated with reduced risk of mortality, especially CVD mortality. Our findings suggest that ALA consumption may be beneficial for death prevention. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO; identifier: CRD42021264532.

Association between prediabetes and adverse outcomes in heart failure

AIMS

Patients with heart failure (HF) and with diabetes experienced significantly worse outcomes than those without diabetes. However, data on the prognostic impact of prediabetes in HF are inconclusive. This meta-analysis aimed to explore the association between prediabetes and the risk of all-cause mortality and adverse cardiac outcomes in patients with HF.

MATERIALS AND METHODS

We searched multiple electronic databases (PubMed, Embase and Google Scholar) for relevant studies up to 31 March 2021. Studies were included for analysis if multivariable adjusted relative risks of adverse outcomes were reported in patients with prediabetes and with HF compared with those with normoglycaemia. Random-effects models were used to calculate the pooled hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Twelve studies comprising 28 643 patients with HF reported the risk of all-cause mortality and cardiac outcomes associated with prediabetes. The prevalence of prediabetes ranged from 9.6% to 37.2%. After a median follow-up duration of 2.3 years, patients with HF and with prediabetes were associated with an increased risk of all-cause mortality (HR 1.29, 95% CI 1.06-1.58), cardiovascular mortality (HR 1.59, 95% CI 1.09-2.32), HF hospitalization (HR 1.33, 95% CI 1.09-1.61), all-cause mortality and/or HF hospitalization (HR 1.22, 95% CI 1.01-1.47), as well as cardiovascular mortality and/or HF hospitalization (HR 1.21, 95% CI 1.07-1.37).

CONCLUSIONS

Prediabetes is associated with a worse prognosis in patients with HF. Further risk stratification and effective treatment strategies are needed in patients with prediabetes and with HF to improve the prognosis.