Prognostic value of leucine/phenylalanine ratio as an amino acid profile of heart failure

Kidney-tonifying blood-activating decoction delays ventricular remodeling in rats with chronic heart failure by regulating gut microbiota and metabolites and p38 mitogen-activated protein kinase/p65 nuclear factor kappa-B/aquaporin-4 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Myocardial infarction has likely contributed to the increased prevalence of heart failure(HF).As a result of ventricular remodeling and reduced cardiac function, colonic blood flow decreases, causing mucosal ischemia and hypoxia of the villous structure of the intestinal wall.This damage in gut barrier function increases bowel wall permeability, leading to fluid metabolism disorder,gut microbial dysbiosis, increased gut bacteria translocation into the circulatory system and increased circulating endotoxins, thus promoting a typical inflammatory state.Traditional Chinese Medicine plays a key role in the prevention and treatment of HF.Kidney-tonifying Blood-activating(KTBA) decoction has been proved for clinical treatment of chronic HF.However,the mechanism of KTBA decoction on chronic HF is still unclear.

AIMS OF THE STUDY

The effect of KTBA decoction on gut microbiota and metabolites and p38MAPK/p65NF-κB/AQP4 signaling in rat colon was studied to investigate the mechanism that KTBA decoction delays ventricular remodeling and regulates water metabolism disorder in rats with HF after myocardial infarction based on the theory of "Kidney Storing Essence and Conducting Water".

MATERIAL AND METHODS

In vivo,a rat model of HF after myocardial infarction was prepared by ligating the left anterior descending coronary artery combined with exhaustive swimming and starvation.The successful modeling rats were randomly divided into five groups:model group, tolvaptan group(gavaged 1.35mg/(kg•D) tolvaptan),KTBA decoction group(gavaged 15.75g/(kg•D) of KTBA decoction),KTBA decoction combined with SB203580(p38MAPK inhibitor) group(gavaged 15.75g/(kg•D) of KTBA decoction and intraperitoneally injected 1.5mg/(kg•D) of SB203580),and KTBA decoction combined with PDTC(p65NF-kB inhibitor) group(gavaged 15.75g/(kg•D) of KTBA decoction and intraperitoneally injected 120mg/(kg•D) of PDTC).The sham-operation group and model group were gavaged equal volume of normal saline.After 4 weeks of intervention with KTBA decoction,the effect of KTBA decoction on the cardiac structure and function of chronic HF model rats was observed by ultrasonic cardiogram.General state and cardiac index in rats were evaluated.Enzyme linked immunosorbent assay(ELISA) was used to measure N-terminal pro-brain natriuretic peptide (NT-proBNP) concentration in rat serum.Hematoxylin and eosin(H&E) staining,and transmission electron microscope(TEM) were used to observe the morphology and ultrastructure of myocardial and colonic tissue,and myocardial fibrosis was measured by Masson's staining.Cardiac E-cadherin level was detected by Western blot.The mRNA expression and protein expression levels of p38MAPK,I-κBα, p65NF-κB,AQP4,Occludin and ZO-1 in colonic tissue were detected by reverse transcription-quantitative real-time polymerase chain reaction(RT-qPCR) and immunohistochemistry. Protein expression of p38MAPK, p-p38MAPK,I-κBα,p-I-κBα,p65NF-κB, p-p65NF-κB,AQP4,Occludin and ZO-1 in rat colon was detected using Western blot.Colonic microbiota and serum metabolites were respectively analyzed by amplicon sequencing and liquid chromatography-mass spectrometry.In vitro, CCD-841CoN cell was placed in the ischemic solution under hypoxic conditions (94%N2,5%CO2,and 1%O2) in a 37 °C incubator to establish an ischemia and hypoxia model.The CCD-841CoN cells were divided into 7 groups, namely blank group and model group with normal rat serum plus control siRNA, tolvaptan group with rat serum containing tolvaptan plus control siRNA, KTBA group with rat serum containing KTBA plus control siRNA, KTBA plus p38MAPK siRNA group, KTBA plus p65NF-κB siRNA group,and KTBA plus AQP4siRNA group.After 24h and 48h of intervention with KTBA decoction,RT-qPCR,immunofluorescence and Western blot was used to detect the mRNA expression and protein expression levels of p38MAPK,I-κBα,p65NF-κB,AQP4, Occludin and ZO-1 in CCD-841CoN cells.

RESULTS

Compared with the model, KTBA decoction improved the general state, decraesed the serum NT-proBNP level,HW/BW ratio, LVIDd and LVIDs, increased E-cadherin level,EF and FS,reduced number of collagen fibers deposited in the myocardial interstitium,and recovered irregular arrangement of myofibril and swollen or vacuolated mitochondria with broken crista in myocardium.Moreover, KTBA decoction inhibited the expression of p38MAPK,I-κBα,and p65NF-κB and upregulated AQP4, Occludin and ZO-1 in colon tissues and CCD-841CoN cells.Additionally,p38siRNA or SB203580, p65siRNA or PDTC, and AQP4siRNA partially weakened the protective effects of KTBA in vitro and vivo.Notably,The LEfSe analysis results showed that there were six gut biomaker bacteria in model group, including Allobaculum, Bacillales,Turicibacter, Turicibacterales,Turicibacteraceae,and Bacilli. Besides, three gut biomaker bacteria containing Deltaproteobacteria, Desulfovibrionaceae,and Desulfovibrionales were enriched by KTBA treatment in chronic HF model.There were five differential metabolites, including L-Leucine,Pelargonic acid, Capsidiol,beta-Carotene,and L- Erythrulose, which can be regulated back in the same changed metabolic routes by the intervention of KTBA.L-Leucine had the positive correlation with Bacillales, Turicibacterales,Turicibacteraceae,and Turicibacter.L-Leucine significantly impacts Protein digestion and absorption, Mineral absorption,and Central carbon metabolism in cancer regulated by KTBA, which is involved in the expression of MAPK and tight junction in intestinal epithelial cells.

CONCLUSIONS

KTBA decoction manipulates the expression of several key proteins in the p38MAPK/p65NF-κB/AQP4 signaling pathway, modulates gut microbiota and metabolites toward a more favorable profile, improves gut barrier function, delays cardiomyocyte hypertrophy and fibrosis,and improves cardiac function.

Prognostic Significance of Phenylalanine in Heart Failure: Clinical Insights and Inter-Organ Crosstalk Snapshot

Background: Heart failure (HF) remains a leading cause of morbidity and mortality globally, necessitating the identification of reliable prognostic biomarkers to guide therapeutic interventions. Recent clinical observations have underscored phenylalanine (PHE) as a prognostic marker in HF, although the mechanisms involving inter-organ crosstalk remain understood. Methods: This study adopted a dull approach, with a retrospective analysis of 550 HF patients to establish the prognostic value of pre-discharge PHE levels and a study on the inter-organ crosstalk of PHE among 24 patients. We analyzed the correlations between PHE concentrations and clinical outcomes, alongside a comprehensive examination of PHE metabolism across the skeletal muscle, liver, heart, kidney, and lung. Results: In the clinical prognostic analysis of 550 patients hospitalized for acute decompensated HF, elevated PHE levels (≥65.6 μM) were significantly and independently associated with increased all-cause mortality during a median follow-up of 4.5 years (log rank = 36.7, p < 0.001), underscoring its value as a prognostic marker in HF. The inter-organic crosstalk study elucidated the mechanism associated with PHE elevation in patients with HF, characterized by an increase in PHE output in skeletal muscle and a decrease in hepatic and cardiac PHE uptakes. Notably, PHE concentration gradients across these organs were correlated with HF severity, such as the NYHA functional class, B-type natriuretic peptide levels, and the presence of acute HF. Conclusions: Our findings confirm the prognostic significance of PHE in patients with HF and unveil the complex metabolic interplay among key organs that contribute to PHE dysregulation. These insights not only reinforce the importance of metabolic monitoring in HF management but also open avenues for therapeutic targets.

The Role of Branched-chain Amino Acids and Their Metabolism in Cardiovascular Diseases

Branched-chain amino acids (BCAAs), including leucine, isoleucine, and valine, are essential amino acids for protein synthesis. Recent studies have yielded new insights into their diverse physiological and pathological roles in health and disease. Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality globally. An increasing number of clinical studies have demonstrated that high levels of circulating BCAAs are associated with an increased risk of CVDs. Animal studies have provided preliminary evidence linking BCAA intake and metabolism with cardiovascular diseases. Despite these insights, the causal relationship between BCAA metabolism and CVD remains poorly established, and the underlying mechanisms remain incompletely understood. Here, we aim to provide an update on the current understanding of the roles of BCAAs and their metabolism in the development and progression of various CVDs. We also discuss the potential strategies targeting BCAA nutrition and metabolism for the prevention and treatment of CVDs.

Unveiling the relationship between gut microbiota and heart failure: Recent understandings and insights

Gut microbiota, which comprises a broad range of bacteria inhabiting the human intestines, plays a crucial role in establishing a mutually beneficial relationship with the host body. Dysbiosis refers to the perturbations in the composition or functioning of the microbial community, which can result in a shift from a balanced microbiota to an impaired state. This alteration has the potential to contribute to the development of chronic systemic inflammation. Heart failure (HF) is a largely prevalent clinical condition that has been demonstrated to have variations in the gut microbiome, indicating a potential active involvement in the pathogenesis and advancement of the disease. The exploration of the complex interplay between the gut microbiome and HF presents a potential avenue for the discovery of innovative biomarkers, preventive measures, and therapeutic targets. This review aims to investigate the impact of gut bacteria on HF.

Low Valine Serum Levels Predict Increased 1-Year Mortality in Acute Heart Failure Patients

Considering the relationship between disease severity and the extent of metabolic derangement in heart failure, we hypothesized that the serum levels of metabolites may have prognostic value for 1-year mortality in acute heart failure (AHF). The AHF study was a prospective, observational study enrolling consecutive patients hospitalized due to AHF. Metabolites were measured in serum collected at admission using NMR spectroscopy. Out of 315 AHF patients, 118 (37.5%) died within 1 year after hospitalization for AHF. The serum levels of 8 out of 49 identified metabolites were significantly different between patients who were alive and those who died within 1 year after hospitalization for AHF. Of these, only valine was significantly associated with 1-year mortality (hazard ratio 0.73 per 1 standard deviation increase, 95% confidence interval: 0.59-0.90, p = 0.003) in the multivariable Cox regression analyses. Kaplan-Maier analysis showed significantly higher survival rates in AHF patients with valine levels above the median (>279.2 µmol/L) compared to those with valine levels ≤ 279.2 µmol/L. In a receiver operating characteristics curve analysis, valine was able to discriminate between the two groups with an area under the curve of 0.65 (95% CI 0.59-0.72). We conclude that valine serum levels might be of prognostic value in AHF.

Elevated branched-chain amino acid promotes atherosclerosis progression by enhancing mitochondrial-to-nuclear H2O2-disulfide HMGB1 in macrophages

As the essential amino acids, branched-chain amino acid (BCAA) from diets is indispensable for health. BCAA supplementation is often recommended for patients with consumptive diseases or healthy people who exercise regularly. Latest studies and ours reported that elevated BCAA level was positively correlated with metabolic syndrome, diabetes, thrombosis and heart failure. However, the adverse effect of BCAA in atherosclerosis (AS) and its underlying mechanism remain unknown. Here, we found elevated plasma BCAA level was an independent risk factor for CHD patients by a human cohort study. By employing the HCD-fed ApoE^-/- mice of AS model, ingestion of BCAA significantly increased plaque volume, instability and inflammation in AS. Elevated BCAA due to high dietary BCAA intake or BCAA catabolic defects promoted AS progression. Furthermore, BCAA catabolic defects were found in the monocytes of patients with CHD and abdominal macrophages in AS mice. Improvement of BCAA catabolism in macrophages alleviated AS burden in mice. The protein screening assay revealed HMGB1 as a potential molecular target of BCAA in activating proinflammatory macrophages. Excessive BCAA induced the formation and secretion of disulfide HMGB1 as well as subsequent inflammatory cascade of macrophages in a mitochondrial-nuclear H₂O₂ dependent manner. Scavenging nuclear H₂O₂ by overexpression of nucleus-targeting catalase (nCAT) effectively inhibited BCAA-induced inflammation in macrophages. All of the results above illustrate that elevated BCAA promotes AS progression by inducing redox-regulated HMGB1 translocation and further proinflammatory macrophage activation. Our findings provide novel insights into the role of animo acids as the daily dietary nutrients in AS development, and also suggest that restricting excessive dietary BCAA consuming and promoting BCAA catabolism may serve as promising strategies to alleviate and prevent AS and its subsequent CHD.

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.

Understanding How Heart Metabolic Derangement Shows Differential Stage Specificity for Heart Failure with Preserved and Reduced Ejection Fraction

Heart failure (HF) is a clinical condition defined by structural and functional abnormalities in the heart that gradually result in reduced cardiac output (HFrEF) and/or increased cardiac pressures at rest and under stress (HFpEF). The presence of asymptomatic individuals hampers HF identification, resulting in delays in recognizing patients until heart dysfunction is manifested, thus increasing the chance of poor prognosis. Given the recent advances in metabolomics, in this review we dissect the main alterations occurring in the metabolic pathways behind the decrease in cardiac function caused by HF. Indeed, relevant preclinical and clinical research has been conducted on the metabolite connections and differences between HFpEF and HFrEF. Despite these promising results, it is crucial to note that, in addition to identifying single markers and reliable threshold levels within the healthy population, the introduction of composite panels would strongly help in the identification of those individuals with an increased HF risk. That said, additional research in the field is required to overcome the current drawbacks and shed light on the pathophysiological changes that lead to HF. Finally, greater collaborative data sharing, as well as standardization of procedures and approaches, would enhance this research field to fulfil its potential.

Prognostic value of malnutrition evaluated using the Global Leadership Initiative on Malnutrition criteria and its association with psoas muscle volume in non-ischemic dilated cardiomyopathy

Heart failure (HF) is a systemic inflammatory disease that causes hypotrophy and skeletal muscle loss. The Global Leadership Initiative on Malnutrition (GLIM) criteria have been developed as a novel evaluation index for malnutrition, with reported usefulness in HF caused by ischemic heart disease. However, reports on the usefulness of malnutrition evaluated by the GLIM criteria in non-ischemic dilated cardiomyopathy (NIDCM) and its relationship with psoas muscle volume are lacking. We investigated the prognostic value of malnutrition evaluated using the GLIM criteria and its association with psoas muscle volume in patients with NIDCM. We enrolled 139 consecutive patients with NIDCM between December 2000 and June 2020. Malnutrition was evaluated using the GLIM criteria on admission. The median follow-up period was 4.7 years. Cardiac events were defined as a composite of cardiac death, hospitalization for worsening HF, and lethal arrhythmia. Furthermore, we measured the psoas muscle volume using computed tomography volumetry in 48 patients. At baseline, the median age was 50 years, and 132 patients (95.0%) had New York Heart Association functional class I or II HF. The median psoas muscle volume was 460.8 cm³. A total of 26 patients (18.7%) were malnourished according to the GLIM criteria. The Kaplan-Meier survival analysis showed that malnourished patients had more cardiac events than non-malnourished patients (log-rank, P < 0.001). The multivariate Cox proportional hazards regression analysis revealed that GLIM criteria-based malnutrition was an independent determinant of cardiac events (hazard ratio, 2.065; 95% confidence interval, 1.166-3.656; P = 0.014). Psoas muscle volume, which was assessed in a total of 48 patients, was lower in malnourished than in non-malnourished patients (median, 369.0 vs. 502.3 cm³; P = 0.035) and correlated with body mass index (r = 0.441; P = 0.002). Nutritional screening using the GLIM criteria may be useful in predicting future cardiac events in patients with NIDCM, reflecting a potential relationship between malnutrition and a low psoas muscle volume.

The cardiosplenic axis: the prognostic role of the spleen in heart failure

Despite the number of available methods to predict prognosis in patients with heart failure, prognosis remains poor, likely because of marked patient heterogeneity and varied heart failure etiologies. Thus, identification of novel prognostic indicators to stratify risk in patients with heart failure is of paramount importance. The spleen is emerging as a potential novel prognostic indicator for heart failure. In this article, we provide an overview of the current prognostic tools used for heart failure. We then introduce the spleen as a potential novel prognostic indicator, before outlining the structure and function of the spleen and introducing the concept of the cardiosplenic axis. This is followed by a focused discussion on the function of the spleen in the immune response and in hemodynamics, as well as a review of what is known about the usefulness of the spleen as an indicator of heart failure. Expert insight into the most effective spleen-related measurement indices for the prognostication of patients with heart failure is provided, and suggestions on how these could be measured in clinical practice are considered. In future, studies in humans will be required to draw definitive links between specific splenic measurements and different heart failure manifestations, as well as to determine whether splenic prognostic measurements differ between heart failure classes and etiologies. These contributions will provide a step forward in our understanding of the usefulness of the spleen as a prognostic predictor in heart failure.

U-Shape Relationship between Plasma Leucine Level and Mortality in the Intensive Care Unit

Patients in the intensive care unit (ICU) are at high risk of mortality which is not well predicted. Previous studies noted that leucine has prognostic value in a variety of diseases. This study investigated whether leucine concentration was a useful biomarker of metabolic and nutritional status and 6-month mortality in ICU. We recruited 454 subjects admitted to ICU (348 and 106 in the initiation and validation cohorts, respectively) with an acute physiology and chronic health evaluation (APACHE II) score ≥ 15. We measured plasma leucine concentrations, traditional biomarkers, and calculated APACHE II and sequential organ failure assessment (SOFA) scores. Leucine levels were weakly correlated with albumin, prealbumin, and transferrin levels (r = 0.30, 0.12, and 0.15, p = 0.001, 0.029, and 0.007, respectively). During follow-up, 116 (33.3%) patients died. Compared to patients with leucine levels between 109 and 174 μM, patients with leucine > 174 μM or <109 μM had a lower cumulative survival rate. Death was also associated with age, higher APACHE II and SOFA scores, C-reactive protein, and longer stays in the ICU, but with lower albumin, prealbumin, and transferrin. Patients with leucine levels > 174 μM had higher alanine aminotransferase levels, but no significant differences in other variables; patients with leucine levels < 109 μM had higher APACHE II and SOFA scores, higher incidence of using inotropic agents, longer ICU and hospital stays, but lower albumin and transferrin levels. Multivariable analysis demonstrated that leucine > 174 μM was an independent predictor of mortality, especially early mortality. However, among patients who stayed in ICU longer than two weeks, leucine < 109 μM was an independent predictor of mortality. In addition, leucine < 109 μM was associated with worse ventilator weaning profiles. These findings were similar in the validation cohort. Our study demonstrated a U-shape relationship between leucine levels and mortality rate in ICU.

In-vivo production of branched-chain amino acids, branched-chain keto acids, and β-hydroxy β-methylbutyric acid

PURPOSE OF REVIEW

The branched-chain amino acids (BCAA), branched-chain keto acids (BCKA), and β-hydroxy β-methylbutyric acid (HMB) have regained interest as food ingredients in health and disease. To support nutritional strategies, it is critical to gain insight into the whole body and transorgan kinetics of these components. We, therefore, reviewed the most recent literature in this field on in vivo analysis of BCAA, BCKA, and HMB kinetics in health and disease.

RECENT FINDINGS

With a new comprehensive metabolic flux analysis BCAA, BCKA, and HMB whole body production, interconversion and disposal rates can be measured simultaneously. Recent studies have provided us with a better understanding of whole-body and transorgan kinetics under postabsorptive, postprandial, hibernating, and lactating conditions. In human pathophysiological conditions like COPD, obesity, and diabetes, the added value of BCAA kinetic measurements over the commonly used concentration measurements only, is discussed.

SUMMARY

This article highlights the importance of implementing BCAA, BCKA, and HMB kinetic studies to further advance the field by gaining more mechanistic insights and providing direction to the development of new targeted (nutritional) strategies.

Metabolite G-Protein Coupled Receptors in Cardio-Metabolic Diseases

G protein-coupled receptors (GPCRs) have originally been described as a family of receptors activated by hormones, neurotransmitters, and other mediators. However, in recent years GPCRs have shown to bind endogenous metabolites, which serve functions other than as signaling mediators. These receptors respond to fatty acids, mono- and disaccharides, amino acids, or various intermediates and products of metabolism, including ketone bodies, lactate, succinate, or bile acids. Given that many of these metabolic processes are dysregulated under pathological conditions, including diabetes, dyslipidemia, and obesity, receptors of endogenous metabolites have also been recognized as potential drug targets to prevent and/or treat metabolic and cardiovascular diseases. This review describes G protein-coupled receptors activated by endogenous metabolites and summarizes their physiological, pathophysiological, and potential pharmacological roles.

Plasma amino acid profiling improves predictive accuracy of adverse events in patients with heart failure

Aims

The clinical outcome of heart failure (HF) is complicated by the presence of multiple comorbidities including malnutrition and cachexia, and prediction of the outcome is still difficult in each patient. Metabolomics including amino acid profiling enables detection of alterations in whole body metabolism. The aim of this study was to determine whether plasma amino acid profiling improves prediction of clinical outcomes in patients with HF.

Methods and results

We retrospectively examined 301 HF patients (70 ± 15 years old; 59% male). Blood samples for measurements of amino acid concentrations were collected in a fasting state after stabilization of HF. Plasma amino acid concentrations were measured using ultraperformance liquid chromatography. Clinical endpoint of this study was adverse event defined as all‐cause death and unscheduled readmission due to worsening HF or lethal arrhythmia. During a mean follow‐up period of 380 ± 214 days, 40 patients (13%) had adverse events. Results of analyses of variable importance in projection score, a measure of a variable's importance in partial least squares–discriminant analysis (PLS‐DA) showed that the top five amino acids being associated with adverse events were 3‐methylhistidine (3‐Me‐His), β‐alanine, valine, hydroxyproline, and tryptophan. Multivariate Cox‐proportional hazard analyses indicated that a high 3‐Me‐His concentration and low β‐alanine and valine concentrations were independently associated with adverse events. When HF patients were divided according to the cut‐off values of amino acids calculated from receiver operating characteristic curves, Kaplan–Meier survival curves showed that event‐free survival rates were lower in HF patients with high 3‐Me‐His than in HF patients with low 3‐Me‐His (68% vs. 91%, P < 0.01). In a subgroup with high 3‐Me‐His, HF patients with low β‐alanine and those with low valine had significantly lower event‐free survival rates than did HF patients with high β‐alanine and those with high valine, respectively. On the other hand, Kaplan–Meier curves of event‐free survival rates did not differ between HF patients with and those without low β‐alanine and low valine in subgroups of patients with low 3‐Me‐His. Inclusion of both high 3‐Me‐His and low β‐alanine or low valine into the adjustment model including N‐terminal pro‐brain natriuretic peptide improved the accuracy of prediction of adverse events after discharge. 3‐Me‐His concentration was associated with muscle mass and nutritional status.

Conclusions

Simple measurement of 3‐Me‐His with either β‐alanine or valine improved the predictive ability for adverse events, indicating the utility of plasma amino acid profiling in risk stratification of hospitalized HF patients.