Serum Zonulin and Endotoxin Levels in Exceptional Longevity versus Precocious Myocardial Infarction

Risk factors and prognostic value of endotoxemia in patients with acute myocardial infarction

Background

There is increasing evidence regarding the association between endotoxemia and the pathogenesis of atherosclerosis and myocardial infarction (MI). During the acute phase of MI, endotoxemia might increase inflammation and drive adverse cardiovascular (CV) outcomes. We aimed to explore the risk factors and prognostic value of endotoxemia in patients admitted for acute MI.

Methods

Patients admitted to the coronary care unit of Dijon University Hospital for type 1 acute MI between 2013 and 2015 were included. Endotoxemia, assessed by plasma lipopolysaccharide (LPS) concentration, was measured by mass spectrometry. Major adverse CV events were recorded in the year following hospital admission.

Results

Data from 245 consecutive MI patients were analyzed. LPS concentration at admission markedly increased with age and diabetes. High LPS concentration was correlated with metabolic biomarkers (glycemia, triglyceride, and total cholesterol) but not with CV (troponin Ic peak and N-terminal pro-brain natriuretic peptide) or inflammatory biomarkers (C-reactive protein, IL6, IL8, and TNFα). LPS concentration was not associated with in-hospital or 1-year outcomes.

Conclusions

In patients admitted for MI, higher levels of endotoxins were related to pre-existing conditions rather than acute clinical severity. Therefore, endotoxins measured on the day of MI could reflect metabolic chronic endotoxemia rather than MI-related acute gut translocation.

The Impacts of Animal-Based Diets in Cardiovascular Disease Development: A Cellular and Physiological Overview

Cardiovascular disease (CVD) is the leading cause of death in the United States, and diet plays an instrumental role in CVD development. Plant-based diets have been strongly tied to a reduction in CVD incidence. In contrast, animal food consumption may increase CVD risk. While increased serum low-density lipoprotein (LDL) cholesterol concentrations are an established risk factor which may partially explain the positive association with animal foods and CVD, numerous other biochemical factors are also at play. Thus, the aim of this review is to summarize the major cellular and molecular effects of animal food consumption in relation to CVD development. Animal-food-centered diets may (1) increase cardiovascular toll-like receptor (TLR) signaling, due to increased serum endotoxins and oxidized LDL cholesterol, (2) increase cardiovascular lipotoxicity, (3) increase renin-angiotensin system components and subsequent angiotensin II type-1 receptor (AT1R) signaling and (4) increase serum trimethylamine-N-oxide concentrations. These nutritionally mediated factors independently increase cardiovascular oxidative stress and inflammation and are all independently tied to CVD development. Public policy efforts should continue to advocate for the consumption of a mostly plant-based diet, with the minimization of animal-based foods.

Microbiome-metabolome reveals that the Suxiao Jiuxin pill attenuates acute myocardial infarction associated with fatty acid metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

The Suxiao Jiuxin pill (SJP) is a Chinese medical patent drug on the national essential drug list of China, with well-established cardiovascular protective effects in the clinic. However, the mechanisms underlying the protective effects of SJP on cardiovascular disease have not yet been elucidated clearly, especially its relationship with the gut microbiota.

AIM OF THE STUDY

This study aimed to investigate the cardioprotective effect of SJP against isoproterenol-induced acute myocardial infarction (AMI) by integrating the gut microbiome and metabolome.

METHODS

A rat model of AMI was generated using isoproterenol. Firstly, the effect of antibiotic (ABX) treatment on the blood absorption and excretion of the main components of SJP were studied. Secondly, 16S rRNA sequencing and untargeted metabolomics were used to discover the improvement of SJP treatment on gut microbiota and host metabolism in AMI rats. Finally, targeted metabolomics was used to verify the effects of SJP treatment on host metabolism in AMI rats.

RESULT

The results showed that ABX treatment could affect the blood absorption and fecal excretion of the main active components of SJP. At the same time, SJP can restore the richness and diversity of gut microbiota, and multiple gut microbiota (including Jeotgalicoccus, Lachnospiraceae, and Blautia) are significantly associated with fatty acids. Untargeted metabolomics also found that SJP could restore the levels of various fatty acid metabolites in serum and cecal contents (p < 0.01, FC > 1.5 and VIP >1). Targeted metabolomics further confirmed that 41, 21, and 39 fatty acids were significantly altered in serum, cecal contents, and heart samples, respectively. Interestingly, these fatty acids belong to the class of eicosanoids, and SJP can significantly downregulate these eicosanoids in AMI rats.

CONCLUSION

The results of this study suggest that SJP may exert its cardioprotective effects by remodeling the gut microbiota and host fatty acid metabolism.

Low Grade Endotoxemia and Oxidative Stress in Offspring of Patients with Early Myocardial Infarction

Background and aims: Offspring of patients with early myocardial infarction are at higher cardiovascular risk, but the underlying physio-pathological mechanism is unclear. NADPH oxidase-type 2 (NOX-2) plays a pivotal role as mediator of oxidative stress and could be involved in activating platelets in these patients. Furthermore, altered intestinal permeability and serum lipopolysaccharide (LPS) could be a trigger to promote NOX-2 activation and platelet aggregation. This study aims to evaluate the behavior of low grade endotoxemia, oxidative stress and platelet activation in offspring of patients with early myocardial infarction. Methods: We enrolled, in a cross-sectional study, 46 offspring of patients with early myocardial infarction and 86 healthy subjects (HS). LPS levels and gut permeability (assessed by zonulin), oxidative stress (assessed by serum NOX-2-derived peptide (sNOX2-dp) release, hydrogen peroxide (H₂O₂) production and isoprostanes), serum nitric oxide (NO) bioavailability and platelet activation (by serum thromboxane B2 (TXB2) and soluble P-Selectin (sP-Selectin)) were analyzed. Results: Compared to HS, offspring of patients with early myocardial infarction had higher values of LPS, zonulin, serum isoprostanes, sNOX2-dp H₂O₂, TXB2, p-selectin and lower NO bioavailability. Logistic regression analysis showed that the variables associated with offspring of patients with early myocardial infarction were LPS, TXB2 and isoprostanes. The multiple linear regression analysis confirmed that serum NOX-2, isoprostanes, p-selectin and H₂O₂ levels were significantly associated to LPS. Furthermore, serum LPS, isoprostanes and TXB2 levels were significantly associated with sNOX-2-dp. Conclusions: Offspring of patients with early myocardial infarction have a low grade endotoxemia that could generate oxidative stress and platelet activation increasing their cardiovascular risk. Future studies are needed to understand the role of dysbiosis in this population.

Zonulin as a Potential Therapeutic Target in Microbiota-Gut-Brain Axis Disorders: Encouraging Results and Emerging Questions

The relationship between dysbiosis and central nervous diseases has been proved in the last 10 years. Microbial alterations cause increased intestinal permeability, and the penetration of bacterial fragment and toxins induces local and systemic inflammatory processes, affecting distant organs, including the brain. Therefore, the integrity of the intestinal epithelial barrier plays a central role in the microbiota-gut-brain axis. In this review, we discuss recent findings on zonulin, an important tight junction regulator of intestinal epithelial cells, which is assumed to play a key role in maintaining of the blood-brain barrier function. In addition to focusing on the effect of microbiome on intestinal zonulin release, we also summarize potential pharmaceutical approaches to modulate zonulin-associated pathways with larazotide acetate and other zonulin receptor agonists or antagonists. The present review also addresses the emerging issues, including the use of misleading nomenclature or the unsolved questions about the exact protein sequence of zonulin.

Food, gut barrier dysfunction, and related diseases: A new target for future individualized disease prevention and management

Dysfunction of gut barrier is known as "leaky gut" or increased intestinal permeability. Numerous recent scientific evidences showed the association between gut dysfunction and multiple gastrointestinal tract (GI) and non-GI diseases. Research also demonstrated that food plays a crucial role to cause or remedy gut dysfunction related to diseases. We reviewed recent articles from electronic databases, mainly PubMed. The data were based on animal models, cell models, and human research in vivo and in vitro models. In this comprehensive review, our aim focused on the relationship between dietary factors, intestinal permeability dysfunction, and related diseases. This review synthesizes currently available literature and is discussed in three parts: (a) the mechanism of gut barrier and function, (b) food and dietary supplements that may promote gut health, and food or medication that may alter gut function, and (c) a table that organizes the synthesized information by general mechanisms for diseases related to leaky gut/intestinal permeability and associated dietary influences. With future research, dietary intervention could be a new target for individualized disease prevention and management.

Endotoxemia in Acute Heart Failure and Cardiogenic Shock: Evidence, Mechanisms and Therapeutic Options

Acute heart failure and cardiogenic shock are frequently occurring and deadly conditions. In patients with those conditions, endotoxemia related to gut injury and gut barrier dysfunction is usually described as a driver of organ dysfunction. Because endotoxemia might reciprocally alter cardiac function, this phenomenon has been suggested as a potent vicious cycle that worsens organ perfusion and leading to adverse outcomes. Yet, evidence beyond this phenomenon might be overlooked, and mechanisms are not fully understood. Subsequently, even though therapeutics available to reduce endotoxin load, there are no indications to treat endotoxemia during acute heart failure and cardiogenic shock. In this review, we first explore the evidence regarding endotoxemia in acute heart failure and cardiogenic shock. Then, we describe the main treatments for endotoxemia in the acute setting, and we present the challenges that remain before personalized treatments against endotoxemia can be used in patients with acute heart failure and cardiogenic shock.

Can increased intestinal permeability and low-grade endotoxemia be the triggering pathogenesis in isolated coronary artery ectasia?

PURPOSE

Isolated coronary artery ectasia (ICAE) is a rare coronary artery disease (CAD) encountered during coronary angiography. Although many mechanisms have been suggested today that may be associated with ICAE, the underlying pathogenesis has not been fully understood. In this study, we aimed to reveal the possible relationship between intestinal permeability and ICAE.

METHODS

Of the 12 850 patients who underwent coronary angiography, 138 consecutive patients with ICAE and 140 age- and sex-matched subjects with normal coronary arteries as the control group and 140 subjects with stenotic CAD were included in the study.

RESULTS

Serum zonulin and lipopolysaccharide levels were significantly higher in patients with ICAE than in the control group and CAD group. Additionally, zonulin and lipopolysaccharide levels were significantly higher in the CAD group than in the ICAE group. In the correlation analysis, serum zonulin levels were correlated with the mean diameter and length of the ecstatic segment. In multivariate analysis, zonulin and lipopolysaccharide were identified as independent predictors for ICAE.

CONCLUSION

These results suggest that there may be a pathophysiological relationship between increased intestinal permeability and ICAE.

Targeting the gut to prevent and counteract metabolic disorders and pathologies during aging

Impairment of gut function is one of the explanatory mechanisms of health status decline in elderly population. These impairments involve a decline in gut digestive physiology, metabolism and immune status, and associated to that, changes in composition and function of the microbiota it harbors. Continuous deteriorations are generally associated with the development of systemic dysregulations and ultimately pathologies that can worsen the initial health status of individuals. All these alterations observed at the gut level can then constitute a wide range of potential targets for development of nutritional strategies that can impact gut tissue or associated microbiota pattern. This can be key, in a preventive manner, to limit gut functionality decline, or in a curative way to help maintaining optimum nutrients bioavailability in a context on increased requirements, as frequently observed in pathological situations. The aim of this review is to give an overview on the alterations that can occur in the gut during aging and lead to the development of altered function in other tissues and organs, ultimately leading to the development of pathologies. Subsequently is discussed how nutritional strategies that target gut tissue and gut microbiota can help to avoid or delay the occurrence of aging-related pathologies.

Sivelestat Alleviates Atherosclerosis by Improving Intestinal Barrier Function and Reducing Endotoxemia

Emerging evidence suggests that atherosclerosis, one of the leading phenotypes of cardiovascular diseases, is a chronic inflammatory disease. During the atherosclerotic process, immune cells play critical roles in vascular inflammation and plaque formation. Meanwhile, gastrointestinal disorder is considered a risk factor in mediating the atherosclerotic process. The present study aimed to utilize sivelestat, a selective inhibitor of neutrophil elastase, to investigate its pharmacological benefits on atherosclerosis and disclose the gastrointestinal–vascular interaction. The activation of intestinal neutrophil was increased during atherosclerotic development in Western diet-fed ApoE^-/- mice. Administration of sivelestat attenuated atherosclerotic phenotypes, including decreasing toxic lipid accumulation, vascular monocyte infiltration, and inflammatory cytokines. Sivelestat decreased intestinal permeability and endotoxemia in atherosclerotic mice. Mechanistically, sivelestat upregulated the expression of zonula occludens-1 in the atherosclerotic mice and recombinant neutrophil elastase protein-treated intestinal epithelial cells. Meanwhile, treatment of sivelestat suppressed the intestinal expression of inflammatory cytokines and NF-κB activity. In contrast, administration of lipopolysaccharides abolished the anti-atherosclerotic benefits of sivelestat in the Western diet-fed ApoE^-/- mice. Further clinical correlation study showed that the circulating endotoxin level and intestinal neutrophil elastase activity were positively correlated with carotid intima-medial thickness in recruited subjects. In conclusion, sivelestat had pharmacological applications in protection against atherosclerosis, and intestinal homeostasis played one of the critical roles in atherosclerotic development.

Intestinal barrier dysfunction as a therapeutic target for cardiovascular disease

The gut microbiome and intestinal dysfunction have emerged as potential contributors to the development of cardiovascular disease (CVD). Alterations in gut microbiome are well documented in hypertension, atherosclerosis, and heart failure and have been investigated as a therapeutic target. However, a perhaps underappreciated but related role for intestinal barrier function has become evident. Increased intestinal permeability is observed in patients and mouse models of CVD. This increased intestinal permeability can enhance systemic inflammation, alter gut immune function, and has been demonstrated as predictive of adverse cardiovascular outcomes. The goal of this review is to examine the evidence supporting a role for intestinal barrier function in cardiovascular disease and its prospect as a novel therapeutic target. We outline key studies that have investigated intestinal permeability in hypertension, coronary artery disease, atherosclerosis, heart failure, and myocardial infarction. We highlight the central mechanisms involved in the breakdown of barrier function and look at emerging evidence for restored barrier function as a contributor to promising treatment strategies such as short chain fatty acid, probiotic, and renin angiotensin system-targeted therapeutics. Recent studies of more selective targeting of the intestinal barrier to improve disease outcomes are also examined. We suggest that although current data supporting a contribution of intestinal permeability to CVD pathogenesis are largely associative, it appears to be a promising avenue for further investigation. Additional studies of the mechanisms of barrier restoration in CVD and testing of intestinal barrier-targeted compounds will be required to confirm their potential as a new class of CVD therapeutic.

Intestinal fatty acid-binding protein mediates atherosclerotic progress through increasing intestinal inflammation and permeability

Atherosclerosis is one of leading phenotypes of cardiovascular diseases, featured with increased vascular intima‐media thickness (IMT) and unstable plaques. The interaction between gastrointestinal system and cardiovascular homeostasis is emerging as a hot topic. Therefore, the present study aimed to explore the role of an intestinal protein, intestinal fatty acid‐binding protein (I‐FABP/FABP2) in the atherosclerotic progress. In western diet–fed ApoE^−/− mice, FABP2 was highly expressed in intestine. Silence of intestinal Fabp2 attenuated western diet–induced atherosclerotic phenotypes, including decreasing toxic lipid accumulation, vascular fibrosis and inflammatory response. Mechanistically, intestinal Fabp2 knockdown improved intestinal permeability through increasing the expression of tight junction proteins. Meanwhile, intestinal Fabp2 knockdown mice exhibited down‐regulation of intestinal inflammation in western diet–fed ApoE^−/− mice. In clinical patients, the circulating level of FABP2 was obviously increased in patients with cardiovascular disease and positively correlated with the value of carotid intima‐media thickness, total cholesterol and triglyceride. In conclusion, FABP2‐induced intestinal permeability could address a potential role of gastrointestinal system in the development of atherosclerosis, and targeting on intestinal FABP2 might provide a therapeutic approach to protect against atherosclerosis.

All disease begins in the (leaky) gut: role of zonulin-mediated gut permeability in the pathogenesis of some chronic inflammatory diseases

Improved hygiene leading to reduced exposure to microorganisms has been implicated as one possible cause for the recent "epidemic" of chronic inflammatory diseases (CIDs) in industrialized countries. That is the essence of the hygiene hypothesis that argues that rising incidence of CIDs may be, at least in part, the result of lifestyle and environmental changes that have made us too "clean" for our own good, so causing changes in our microbiota. Apart from genetic makeup and exposure to environmental triggers, inappropriate increase in intestinal permeability (which may be influenced by the composition of the gut microbiota), a "hyper-belligerent" immune system responsible for the tolerance-immune response balance, and the composition of gut microbiome and its epigenetic influence on the host genomic expression have been identified as three additional elements in causing CIDs. During the past decade, a growing number of publications have focused on human genetics, the gut microbiome, and proteomics, suggesting that loss of mucosal barrier function, particularly in the gastrointestinal tract, may substantially affect antigen trafficking, ultimately influencing the close bidirectional interaction between gut microbiome and our immune system. This cross-talk is highly influential in shaping the host gut immune system function and ultimately shifting genetic predisposition to clinical outcome. This observation led to a re-visitation of the possible causes of CIDs epidemics, suggesting a key pathogenic role of gut permeability. Pre-clinical and clinical studies have shown that the zonulin family, a group of proteins modulating gut permeability, is implicated in a variety of CIDs, including autoimmune, infective, metabolic, and tumoral diseases. These data offer novel therapeutic targets for a variety of CIDs in which the zonulin pathway is implicated in their pathogenesis.