Metabolomics: A New Tool in Our Understanding of Congenital Heart Disease

Integrative metabolomics dictate distinctive signature profiles in patients with Tetralogy of Fallot

BACKGROUND

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease (CCHD) with multifactorial etiology. We aimed to investigate the metabolic profiles of CCHD and their independent contributions to TOF.

METHODS

A cohort comprising 42 individuals with TOF and atrial septal defect (ASD) was enrolled. Targeted ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was employed to systematically analyze metabolite levels and identify TOF-associated metabolic profiles.

RESULTS

Of 370 identified metabolites in tissue and 284 in plasma, over one-third of metabolites showed an association with microbiome. Differential metabolic pathways including amino acids biosynthesis, ABC (ATP-binding cassette) transporters, carbon metabolism, and fatty acid biosynthesis, shed light on TOF biological phenotypes. Additionally, ROC curves identified potential biomarkers, such as erythronic acid with an AUC of 0.868 in plasma, and 3-β-hydroxy-bisnor-5-cholenic acid, isocitric acid, glutaric acid, ortho-Hydroxyphenylacetic acid, picolinic acid with AUC close to 1 in tissue, whereas the discriminative performance of those substances significantly improved when combined with clinical phenotypes.

CONCLUSIONS

Distinct metabolic profiles exhibited robust discriminatory capabilities, effectively distinguishing TOF from ASD patients. These metabolites may serve as biomarkers or key molecular players in the intricate metabolic pathways involved in CCHD development.

IMPACT

Distinct metabolic profiles exhibited robust discriminatory capabilities, effectively distinguishing Tetralogy of Fallot from atrial septal defect patients. Similar profiling but inconsistent differential pathways between plasma and tissue. More than one-third metabolites in plasma and tissue are associated with the microbiome. The discovery of biomarkers is instrumental in facilitating early detection and diagnosis of Tetralogy of Fallot. Disturbed metabolism offers insights into interpretation of pathogenesis of Tetralogy of Fallot.

How Will Artificial Intelligence Shape the Future of Decision-Making in Congenital Heart Disease?

Improvements in medical technology have significantly changed the management of congenital heart disease (CHD), offering novel tools to predict outcomes and personalize follow-up care. By using sophisticated imaging modalities, computational models and machine learning algorithms, clinicians can experiment with unprecedented insights into the complex anatomy and physiology of CHD. These tools enable early identification of high-risk patients, thus allowing timely, tailored interventions and improved outcomes. Additionally, the integration of genetic testing offers valuable prognostic information, helping in risk stratification and treatment optimisation. The birth of telemedicine platforms and remote monitoring devices facilitates customised follow-up care, enhancing patient engagement and reducing healthcare disparities. Taking into consideration challenges and ethical issues, clinicians can make the most of the full potential of artificial intelligence (AI) to further refine prognostic models, personalize care and improve long-term outcomes for patients with CHD. This narrative review aims to provide a comprehensive illustration of how AI has been implemented as a new technological method for enhancing the management of CHD.

A Noninvasive Circulating Signature of Combined Right Ventricular Pressure and Volume Overload in Tetralogy of Fallot/Pulmonary Atresia/Major Aortopulmonary Collateral Arteries

Background: Despite surgical advances, children with tetralogy of Fallot/pulmonary atresia/major aortopulmonary collaterals (TOF/PA/MAPCAs) are subject to chronic right ventricular (RV) pressure and volume overload. Current diagnostic tools do not identify adverse myocardial remodeling and cannot predict progression to RV failure. We sought to identify a noninvasive, circulating signature of the systemic response to right heart stress to follow disease progression. Methods: Longitudinal data were collected from patients with TOF/PA/MAPCAs (N = 5) at the time of (1) early RV pressure overload and (2) late RV pressure and volume overload. Plasma protein and microRNA expression were evaluated using high-throughput data-independent mass spectroscopy and Agilent miR Microarray, respectively. Results: At the time of early RV pressure overload, median patient age was 0.34 years (0.02-9.37), with systemic RV pressures, moderate-severe hypertrophy, and preserved systolic function. Late RV pressure and volume overload occurred at a median age of 4.08 years (1.51-10.83), with moderate RV hypertrophy and dilation, and low normal RV function; 277 proteins were significantly dysregulated (log2FC ≥0.6/≤-0.6, FDR≤0.05), predicting downregulation in lipid transport (apolipoproteins), fibrinolytic system, and extracellular matrix structural proteins (talin 1, profilin 1); and upregulation in the respiratory burst. Increasing RV size and decreasing RV function correlated with decreasing structural protein expression. Similarly, miR expression predicted downregulation of extracellular matrix-receptor interactions and upregulation in collagen synthesis. Conclusion: To our knowledge, we show for the first time a noninvasive protein and miR signature reflecting the systemic response to adverse RV myocardial remodeling in TOF/PA/MAPCAs which could be used to follow disease progression.

Metabolomics in Pulmonary Hypertension-A Useful Tool to Provide Insights into the Dark Side of a Tricky Pathology

Pulmonary hypertension (PH) is a multifaceted illness causing clinical manifestations like dyspnea, fatigue, and cyanosis. If left untreated, it often evolves into irreversible pulmonary arterial hypertension (PAH), leading to death. Metabolomics is a laboratory technique capable of providing insights into the metabolic pathways that are responsible for a number of physiologic or pathologic events through the analysis of a biological fluid (such as blood, urine, and sputum) using proton nuclear magnetic resonance spectroscopy or mass spectrometry. A systematic review was finalized according to the PRISMA scheme, with the goal of providing an overview of the research papers released up to now on the application of metabolomics to PH/PAH. So, eighty-five papers were identified, of which twenty-four concerning PH, and sixty-one regarding PAH. We found that, from a metabolic standpoint, the hallmarks of the disease onset and progression are an increase in glycolysis and impaired mitochondrial respiration. Oxidation is exacerbated as well. Specific metabolic fingerprints allow the characterization of some of the specific PH and PAH subtypes. Overall, metabolomics provides insights into the biological processes happening in the body of a subject suffering from PH/PAH. The disarranged metabolic pathways underpinning the disease may be the target of new therapeutic agents. Metabolomics will allow investigators to make a step forward towards personalized medicine.

Comparative Metabolomics in Single Ventricle Patients after Fontan Palliation: A Strong Case for a Targeted Metabolic Therapy

Most studies on single ventricle (SV) circulation take a physiological or anatomical approach. Although there is a tight coupling between cardiac contractility and metabolism, the metabolic perspective on this patient population is very recent. Early findings point to major metabolic disturbances, with both impaired glucose and fatty acid oxidation in the cardiomyocytes. Additionally, Fontan patients have systemic metabolic derangements such as abnormal glucose metabolism and hypocholesterolemia. Our literature review compares the metabolism of patients with a SV circulation after Fontan palliation with that of patients with a healthy biventricular (BV) heart, or different subtypes of a failing BV heart, by Pubmed review of the literature on cardiac metabolism, Fontan failure, heart failure (HF), ketosis, metabolism published in English from 1939 to 2023. Early evidence demonstrates that SV circulation is not only a hemodynamic burden requiring staged palliation, but also a metabolic issue with alterations similar to what is known for HF in a BV circulation. Alterations of fatty acid and glucose oxidation were found, resulting in metabolic instability and impaired energy production. As reported for patients with BV HF, stimulating ketone oxidation may be an effective treatment strategy for HF in these patients. Few but promising clinical trials have been conducted thus far to evaluate therapeutic ketosis with HF using a variety of instruments, including ketogenic diet, ketone esters, and sodium-glucose co-transporter-2 (SGLT2) inhibitors. An initial trial on a small cohort demonstrated favorable outcomes for Fontan patients treated with SGLT2 inhibitors. Therapeutic ketosis is worth considering in the treatment of Fontan patients, as ketones positively affect not only the myocardial energy metabolism, but also the global Fontan physiopathology. Induced ketosis seems promising as a concerted therapeutic strategy.

Idiopathic Pulmonary Arterial Hypertension in Paediatrics Represents Still a Serious Challenge: A Case Series Study

Introduction: Paediatric pulmonary hypertension (PH) represents a heterogeneous illness that is responsible for high morbidity and mortality if left without treatment. Idiopathic pulmonary arterial hypertension (IPAH) is a subtype of PAH rarely seen in paediatrics. Limited long-term data are available. Methods: Over a period of 20 years, 10 paediatric patients were enrolled at two tertiary centres. Their clinical, echocardiographic, and right heart catheterisation (RHC) features and outcome were evaluated. Results: The mean age at first diagnosis was 5.7 ± 5.7 years. The age at the last follow-up was 12.4 ± 6.1 years. The average follow-up was 6.6 ± 0.8 years. There was a female prevalence of 60% (p < 0.05) in this case series. Regarding the NYHA functional class, 80% of IPAH subjects were in class III or IV. The mean saturation was 91 ± 5%. In this regard, 70% of the patients were on a combination of three drugs, with sildenafil (90%) included. On echocardiography, longitudinal right ventricular contractility (TAPSE) was slightly reduced (13.4 ± 2.6 mm), whilst RVSP was severely elevated (101 ± 19 mmHg). The RHC data showed that mPAP was 61.8 ± 23.1 mmHg (p = 0.0017 with RVSP on echocardiography), mRAP was 10.7 ± 3.8 mmHg, CI was 2.6 ± 1 L·min−1·m−2, PVRi was 16.8 ± 12.6 WU·m2, and SVO2 was 63.6 ± 14.8%. Regarding the outcome, two male IPAH patients (20%) died, and 50% underwent lung transplant or were on transplant assessment or already on the waiting list for lung transplantation. One patient underwent a ductus arteriosus stenting (reverse Potts shunt) and another underwent atrial septostomy and stenting. Conclusions: Notwithstanding the progress in medical therapy, IPAH continues to represent a serious challenge, particularly in the paediatric population, with the need for lung transplantation and significant mortality.

Competing Endogenous RNA Regulatory Networks of hsa_circ_0126672 in Pathophysiology of Coronary Heart Disease

Coronary heart disease (CHD) is a global health concern, and its molecular origin is not fully elucidated. Dysregulation of ncRNAs has been linked to many metabolic and infectious diseases. This study aimed to explore the role of circRNAs in the pathogenesis of CHD and predicted a candidate circRNA that could be targeted for therapeutic approaches to the disease. circRNAs associated with CHD were identified and CHD gene expression profiles were obtained, and analyzed with GEO2R. In addition, differentially expressed miRNA target genes (miR-DEGs) were identified and subjected to functional enrichment analysis. Networks of circRNA/miRNA/mRNA and the miRNA/affected pathways were constructed. Furthermore, a miRNA/mRNA homology study was performed. We identified that hsa_circ_0126672 was strongly associated with the CHD pathology by competing for endogenous RNA (ceRNA) mechanisms. hsa_circ_0126672 characteristically sponges miR-145-5p, miR-186-5p, miR-548c-3p, miR-7-5p, miR-495-3p, miR-203a-3p, and miR-21. Up-regulation of has_circ_0126672 affected various CHD-related cellular functions, such as atherosclerosis, JAK/STAT, and Apelin signaling pathways. Our results also revealed a perfect and stable interaction for the hybrid of miR-145-5p with NOS1 and RPS6KB1. Finally, miR-145-5p had the highest degree of interaction with the validated small molecules. Henchashsa_circ_0126672 and target miRNAs, notably miR-145-5p, could be good candidates for the diagnosis and therapeutic approaches to CHD.