Increased mean aliphatic lipid chain length in left ventricular hypertrophy secondary to arterial hypertension: A cross-sectional study

Role of metabolomics in identifying cardiac hypertrophy: an overview of the past 20 years of development and future perspective

Cardiac hypertrophy (CH) is an augmentation of either the right ventricular or the left ventricular mass in order to compensate for the increase of work load on the heart. Metabolic abnormalities lead to histological changes of cardiac myocytes and turn into CH. The molecular mechanisms that lead to initiate CH have been of widespread concern, hence the development of the new field of research, metabolomics: one 'omics' approach that can reveal comprehensive information of the paradigm shift of metabolic pathways network in contrast to individual enzymatic reaction-based metabolites, have attempted and until now only 19 studies have been conducted using experimental animal and human specimens. Nuclear magnetic resonance spectroscopy and mass spectrometry-based metabolomics studies have found that CH is a metabolic disease and is mainly linked to the harmonic imbalance of glycolysis, citric acid cycle, amino acids and lipid metabolism. The current review will summarise the main outcomes of the above mentioned 19 studies that have expanded our understanding of the molecular mechanisms that may lead to CH and eventually to heart failure.

Identification of biomarkers for essential hypertension based on metabolomics

AIM

Essential hypertension (EH) is one of the most important public health problems worldwide. However, the pathogenesis of EH is unclear and early diagnostic methods are lacking. Metabolomics demonstrates great potential for biomarker discovery and the mechanistic exploration of metabolic diseases.

DATA SYNTHESIS

This review included human and animal metabolomics studies related to EH in the PubMed and Web of Science databases between February 1996 and May 2020. The study designs, EH standards, and reported metabolic biomarkers were systematically examined and compared. The pathway analysis was conducted through the online software MetaboAnalyst 4.0. Twenty-two human studies and fifteen animal studies were included in this systematic review. There were many frequently reported biomarkers with consistent trends (e.g., pyruvate, lactic acid, valine, and tryptophan) in human and animal studies, and thus had potential as biomarkers of EH. In addition, several shared metabolic pathways, including alanine, aspartate, and glutamate metabolism, aminoacyl-tRNA biosynthesis, and arginine biosynthesis, were identified in human and animal metabolomics studies. These biomarkers and pathways, closely related to insulin resistance, the inflammatory state, and impaired nitric oxide production, were demonstrated to contribute to EH development.

CONCLUSIONS

This study summarized valuable metabolic biomarkers and pathways that could offer opportunities for the early diagnosis or prediction of EH and the discovery of the metabolic mechanisms of EH.

[Focus on the Myocardial Hypertrophy from the Perspective of Transcriptomics and Metabolomics]

This review presents major directions in studies of myocardial hypertrophy from the aspect of transcriptomics and metabolomics. Understanding of trigger mechanisms of myocardial hypertrophy will permit transition from basic studies to individualized clinical application of innovative technologies in the treatment of heart diseases, such as targeted therapy. At the present time, methods have been developed for diagnostics and prediction of cardiovascular diseases based on the metabolomic profiling and the evaluation of microRNA expression. Progress in studying molecular and genetic processes underlying the development of cardiovascular diseases may provide invaluable information for clinical cardiology.

Application of NMR metabolomics to search for human disease biomarkers in blood

Recently, nuclear magnetic resonance spectroscopy (NMR)-based metabolomics analysis and multivariate statistical techniques have been incorporated into a multidisciplinary approach to profile changes in small molecules associated with the onset and progression of human diseases. The purpose of these efforts is to identify unique metabolite biomarkers in a specific human disease so as to (1) accurately predict and diagnose diseases, including separating distinct disease stages; (2) provide insights into underlying pathways in the pathogenesis and progression of the malady and (3) aid in disease treatment and evaluate the efficacy of drugs. In this review we discuss recent developments in the application of NMR-based metabolomics in searching disease biomarkers in human blood samples in the last 5 years.

Conventional and new electrocardiographic criteria for hypertension-mediated cardiac organ damage: A narrative review

Hypertension-mediated organ damage (HMOD) is frequently observed in hypertensive patients at different cardiovascular (CV) risk profile. This may have both diagnostic and therapeutic implications for the choice of the most appropriate therapies. Among different markers of HMOD, the most frequent functional and structural adaptations can be observed at cardiac level, including left ventricular hypertrophy (LVH), diastolic dysfunction, aortic root dilatation, and left atrial enlargement. In particular, LVH was shown to be a strong and independent risk factor for major CV events, namely myocardial infarction, stroke, congestive heart failure, CV death. Thus, early identification of LVH is a key element for preventing CV events in hypertension. Although echocardiographic assessment of LVH represents the gold standard technique, this is not cost-effective and cannot be adopted in routine clinical practice of hypertension. On the other hand, electrocardiographic (ECG) assessment of HMOD relative to the heart is a simple, reproducible, widely available and cost-effective method to assess the presence of LVH, and could be preferred in large scale screening tests. Several new indicators have been proposed and tested in observational studies and clinical trials of hypertension, in order to improve the relatively low sensitivity of the conventional ECG criteria for LVH, despite high specificity. This article reviews the differences in the use of the main conventional and the new 12 lead ECG criteria of LVH for early assessment of asymptomatic, subclinical cardiac HMOD in a setting of clinical practice of hypertension.

Molecular characterization of particulate organic matter in full scale anaerobic digesters: An NMR spectroscopy study

This study assesses the molecular characteristics of particulate organic matter (POM) in agricultural and food waste digesters and elucidates the molecular properties of the recalcitrant POM fraction, which remains in the digestate after AD process. Molecular properties of POM in influent (substrate) and effluent (digestate) of seven full-scale AD plants (three agricultural waste and four food waste digesters) were characterized and compared using solid-state ¹³C cross-polarization magic angle spinning (CP-MAS) and solution-state ¹H,¹³C heteronuclear single-quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy. Comparison of the POM structural compositions of substrate and digestate from each AD plant revealed an enrichment of protein structures relative to the carbohydrates in most cases, implying a preferential degradation of the carbohydrates over proteins and/or increase of microbial biomass upon AD of agricultural and food wastes. Distinctive molecular structures of labile and recalcitrant fractions of POM, subjected to AD, were identified by comparing the NMR spectra of all substrate and digestate POM. Accordingly, the labile POM fraction in food and agricultural solid wastes is characterized by structural entities of lipids and starch-like carbohydrates, whereas recalcitrant POM structures resemble alkyl and aromatic subunits of amino acids, lignin, and polysaccharides with β-glycosidic linkages. This information serves as a basis to further explore optimization approaches for improving AD of the underutilized POM and the fate of organic matter in digestate-amended arable lands.