Plasma amino acid metabolomic pattern in heart failure patients with either preserved or reduced ejection fraction: The relation to established risk variables and prognosis

Microbial metabolites associated in stool and left ventricle of heart failure patients revealed by meta-analysis

Heart Failure (HF) impacts approximately 64 million people globally. While overall incidence of HF is relatively stable across countries, the overall number of HF patients is increasing due to aging populations. Many articles examine the microbiome in HF, however, studies from humans have not been analyzed systematically. The aim of this meta-analysis is to bridge this gap by analyzing previously published data on human HF patients with untargeted metabolomics to understand whether microbially-mediated metabolites are consistently important for HF status. A systematic survey of the literature identified 708 articles discussing HF, the microbiome, and metabolomics. Of these, 82 were primary studies of HF patients, 61 studied human adults, 23 included an untargeted metabolomics measure, and 3 studies had data that was usable and publicly accessible. These studies include a GCMS study from stool, NMR of saliva and exhaled breath condensate, and LCMS from left ventricle of HF patients undergoing transplantation and unused donor hearts. Significant differences were observed from PCA between HF and controls for stool and left ventricle, but not saliva or EBC samples. OPLS-DA was conducted for stool and ventricle samples, and further revealed significant group differences. Univariate testing with FDR correction revealed 8 significant microbially-relevant metabolites (p < 0.005 after correction), most notably asparagine from left ventricle and 2-methylbutyryl carnitine from stool. Though there is much discussion of the microbiome in health outcomes in HF, there is limited research from human populations. Some microbial co-metabolites from both stool and heart were significantly associated with HF.

A High-Fat Diet Induces Epigenetic 1-Carbon Metabolism, Homocystinuria, and Renal-Dependent HFpEF

BACKGROUND/OBJECTIVES

Chronic gut dysbiosis due to a high-fat diet (HFD) instigates cardiac remodeling and heart failure with preserved ejection fraction (HFpEF), in particular, kidney/volume-dependent HFpEF. Studies report that although mitochondrial ATP citrate lyase (ACLY) supports cardiac function, it decreases more in human HFpEF than HFrEF. Interestingly, ACLY synthesizes lipids and creates hyperlipidemia. Epigenetically, ACLY acetylates histone. The mechanism(s) are largely unknown.

METHODS/RESULTS

One hypothesis is that an HFD induces epigenetic folate 1-carbon metabolism (FOCM) and homocystinuria. This abrogates dipping in sleep-time blood pressure and causes hypertension and morning heart attacks. We observed that probiotics/lactobacillus utilize fat/lipids post-biotically, increasing mitochondrial bioenergetics and attenuating HFpEF. We suggest novel and paradigm-shift epigenetic mitochondrial sulfur trans-sulfuration pathways that selectively target HFD-induced HFpEF. Previous studies from our laboratory, using a single-cell analysis, revealed an increase in the transporter (SLC25A) of s-adenosine-methionine (SAM) during elevated levels of homocysteine (Hcy, i.e., homocystinuria, HHcy), a consequence of impaired epigenetic recycling of Hcy back to methionine due to an increase in the FOCM methylation of H3K4, K9, H4K20, and gene writer (DNMT) and decrease in eraser (TET/FTO). Hcy is transported to mitochondria by SLC7A for clearance via sulfur metabolomic trans-sulfuration by 3-mercaptopyruvate sulfur transferase (3MST).

CONCLUSIONS

We conclude that gut dysbiosis due to HFD disrupts rhythmic epigenetic memory via FOCM and increases in DNMT1 and creates homocystinuria, leading to a decrease in mitochondrial trans-sulfuration and bioenergetics. The treatment with lactobacillus metabolites fat/lipids post-biotically and bi-directionally produces folic acid and lactone-ketone body that mitigates the HFD-induced mitochondrial remodeling and HFpEF.

Tyrosine to threonine ratio was related to heart failure with reduced or mildly reduced ejection fraction

AIMS

We aim to explore the associations between serum tyrosine (Tyr) to threonine (Thr) ratio and chronic heart failure (HF) with reduced or mildly reduced ejection fraction (EF) (HFrEF or HFmrEF).

METHODS AND RESULTS

The study recruited 418 subjects (77.5% males, mean age 65.2 ± 12.5 years), including 318 HF subjects (HFrEF or HFmrEF) and 100 cardiovascular subjects without acute or chronic HF [including heart failure with preserved ejection fraction (HFpEF)] as controls. Serum levels of 21 kinds of amino acids (AAs) were measured by mass spectrometry. Logistic regression analysis was conducted to measuring the association between the AAs levels and the presence of HF. Event-free survival was determined by Kaplan-Meier curves and differences in survival were assessed using log-rank tests. Cox regression analysis was used to assess the prognostic value of AAs in HF. Receiver-operating characteristic (ROC) curve was performed to further confirm regression analysis. Along with the control, HFmrEF, and HFrEF subjects, serum tyrosine (Tyr) gradually increased (64.43 ± 15.28 μmol/L vs. 71.79 ± 18.74 μmol/L vs. 77.32 ± 25.90 μmol/L, P < 0.001) while serum threonine (Thr) decreased (165.21 ± 40.09 μmol/L vs. 144.93 ± 44.56 μmol/L vs. 135.25 ± 41.25 μmol/L, P < 0.001). Tyr/Thr ratio was the independent risk factor for the presence of HF in all subjects [odds ratio (OR), 3.510; 95% confidence interval (CI): 2.445-5.040; P < 0.001]. After following up for a mean year (11.10 ± 2.80 months) in 269 HF subjects (75.1% males, mean age 65.2 ± 12.8 years), the higher Tyr/Thr ratio was associated with a higher risk of HF endpoint events in HF subjects [hazard ratio (HR), 2.901; 95% CI: 1.228-6.851; P = 0.015]. By comparing the area under the receiver-operating characteristic curve (AUC), Tyr/Thr ratio was superior to Fischer's ratio (FR) in predicting HF occurrence (0.767:0.573, P < 0.001) or cardiovascular (CV) death (0.715:0.550, P = 0.047).

CONCLUSIONS

Circulating elevated Tyr/Thr ratio confer an increased risk for the presence of HF and poor prognosis. Tyr/Thr index outweighs FR index in predicting HF occurrence or CV death.

Metabolomic insights in advanced cardiomyopathy of chronic chagasic and idiopathic patients that underwent heart transplant

Heart failure (HF) studies typically focus on ischemic and idiopathic heart diseases. Chronic chagasic cardiomyopathy (CCC) is a progressive degenerative inflammatory condition highly prevalent in Latin America that leads to a disturbance of cardiac conduction system. Despite its clinical and epidemiological importance, CCC molecular pathogenesis is poorly understood. Here we characterize and discriminate the plasma metabolomic profile of 15 patients with advanced HF referred for heart transplantation - 8 patients with CCC and 7 with idiopathic dilated cardiomyopathy (IDC) - using gas chromatography/quadrupole time-of-flight mass spectrometry. Compared to the 12 heart donor individuals, also included to represent the control (CTRL) scenario, patients with advanced HF exhibited a metabolic imbalance with 21 discriminating metabolites, mostly indicative of accumulation of fatty acids, amino acids and important components of the tricarboxylic acid (TCA) cycle. CCC vs. IDC analyses revealed a metabolic disparity between conditions, with 12 CCC distinctive metabolites vs. 11 IDC representative metabolites. Disturbances were mainly related to amino acid metabolism profile. Although mitochondrial dysfunction and loss of metabolic flexibility may be a central mechanistic event in advanced HF, metabolic imbalance differs between CCC and IDC populations, possibly explaining the dissimilar clinical course of Chagas' patients.

Nuclear ATR lysine-tyrosylation protects against heart failure by activating DNA damage response

Dysregulated amino acid increases the risk for heart failure (HF) via unclear mechanisms. Here, we find that increased plasma tyrosine and phenylalanine levels are associated with HF. Increasing tyrosine or phenylalanine by high-tyrosine or high-phenylalanine chow feeding exacerbates HF phenotypes in transverse aortic constriction and isoproterenol infusion mice models. Knocking down phenylalanine dehydrogenase abolishes the effect of phenylalanine, indicating that phenylalanine functions by converting to tyrosine. Mechanistically, tyrosyl-tRNA synthetase (YARS) binds to ataxia telangiectasia and Rad3-related gene (ATR), catalyzes lysine tyrosylation (K-Tyr) of ATR, and activates the DNA damage response (DDR) in the nucleus. Increased tyrosine inhibits the nuclear localization of YARS, inhibits the ATR-mediated DDR, accumulates DNA damage, and elevates cardiomyocyte apoptosis. Enhancing ATR K-Tyr by overexpressing YARS, restricting tyrosine, or supplementing tyrosinol, a structural analog of tyrosine, promotes YARS nuclear localization and alleviates HF in mice. Our findings implicate facilitating YARS nuclear translocation as a potential preventive and/or interfering measure against HF.

Dysregulated amino acid metabolism in heart failure: role of gut microbiome

PURPOSE OF REVIEW

The importance of amino acid metabolism in heart failure has often been overlooked, especially in advanced stages. Metabolism of dietary compounds by gut microbiota generates a wide range of metabolites that can directly or indirectly modulate end-organ functions in their hosts. Herein, we describe recently discovered mechanistic links between various gut microbial metabolic pathways of amino acids and their derivatives in the pathophysiology of heart failure.

RECENT FINDINGS

Growing evidence points to incremental prognostic value in amino acid profiling in patients with heart failure. Reducing branched-chain amino acid levels in the failing heart may have a cardioprotective role. Gut microbiome-related amino acid, including amino acid supplementation, dietary interventions, or microbial enzyme inhibition, can be targeted to modify cardiovascular risks.

SUMMARY

Interplay between the gut microbiome and amino acid metabolism may contribute to disease progression in heart failure. Further investigations are warranted to uncover opportunities for intervention.

Identification of metabolomic profile related to adult Fontan pathophysiology

Background

Metabolic disorders are important pathophysiologies that can cause multiple organ dysfunction and worsen prognosis in Fontan patients. This study aimed to comprehensively evaluate the metabolomic profile of adult Fontan patients and characterize its pathophysiology in relation to 2 control groups.

Methods and Results

We performed metabolomic analysis of 31 plasma samples using capillary electrophoresis time-of-flight mass spectrometry. This observational cross-sectional study compared plasma metabolites of 14 heterogeneous adult Fontan patients with those of control groups, including 9 patients with congenital heart disease after biventricular repair and 8 normal healthy controls. Fontan patients exhibited significant differences in intermediate metabolite concentrations related to glycolysis, the tricarboxylic acid (TCA) cycle, and the urea cycle. The plasma concentrations of lactic acid, 2-oxoglutarate, isocitric acid, malic acid, cis-aconitic acid, arginine, citrulline, and the ratio of ornithine/citrulline showed significantly differences among the groups. Multiple logistic regression analysis with a stepwise selection-elimination method identified 2-oxoglutaric acid (odds ratio [OR] 1.98, 95% confidence interval [CI] 1.05–3.76) and cis-aconitic acid (OR 2.69, 95% CI 1.04–6.99) as independently associated with Fontan patients. After adjustment for the covariates of age and gender, 2-oxoglutaric acid (OR 1.97, 95% CI 0.98–3.93) and cis-aconitic acid (OR 3.88, 95% CI 0.99–15.2) showed remarkable relationships with Fontan patients.

Conclusions

The present findings suggest that abnormalities in the TCA cycle and amino acid metabolism are distinguishing features in the pathophysiology of Fontan patients. Future metabolomic studies will assist in developing biomarkers for the early prediction of “silent” Fontan pathophysiologies.