Multinomial machine learning identifies independent biomarkers by integrated metabolic analysis of acute coronary syndrome.

A multi-class classification model for acute coronary syndrome (ACS) remains to be constructed based on multi-fluid metabolomics. Major confounders may exert spurious effects on the relationship between metabolism and ACS. The study aims to identify an independent biomarker panel for the multiclassification of HC, UA, and AMI by integrating serum and urinary metabolomics. We performed a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based metabolomics study on 300 serum and urine samples from 44 patients with unstable angina (UA), 77 with acute myocardial infarction (AMI), and 29 healthy controls (HC). Multinomial machine learning approaches, including multinomial adaptive least absolute shrinkage and selection operator (LASSO) regression and random forest (RF), and assessment of the confounders were applied to integrate a multi-class classification biomarker panel for HC, UA and AMI. Different metabolic landscapes were portrayed during the transition from HC to UA and then to AMI. Glycerophospholipid metabolism and arginine biosynthesis were predominant during the progression from HC to UA and then to AMI. The multiclass metabolic diagnostic model (MDM) dependent on ACS, including 2-ketobutyric acid, LysoPC(18:2(9Z,12Z)), argininosuccinic acid, and cyclic GMP, demarcated HC, UA, and AMI, providing a C-index of 0.84 (HC vs. UA), 0.98 (HC vs. AMI), and 0.89 (UA vs. AMI). The diagnostic value of MDM largely derives from the contribution of 2-ketobutyric acid, and LysoPC(18:2(9Z,12Z)) in serum. Higher 2-ketobutyric acid and cyclic GMP levels were positively correlated with ACS risk and atherosclerosis plaque burden, while LysoPC(18:2(9Z,12Z)) and argininosuccinic acid showed the reverse relationship. An independent multiclass biomarker panel for HC, UA, and AMI was constructed using the multinomial machine learning methods based on serum and urinary metabolite signatures.

Identification of the metabolic remodeling profile in the early-stage of myocardial ischemia and the contributory role of mitochondrion.

Cardiac remodeling is the primary pathological feature of chronic heart failure. Prompt inhibition of remodeling in acute coronary syndrome has been a standard procedure, but the morbidity and mortality are still high. Exploring the characteristics of ischemia in much earlier stages and identifying its biomarkers are essential for introducing novel mechanisms and therapeutic strategies. Metabolic and structural remodeling of mitochondrion is identified to play key roles in ischemic heart disease. The mitochondrial metabolic features in early ischemia have not previously been described. In the present study, we established a mouse heart in early ischemia and explored the mitochondrial metabolic profile using metabolomics analysis. We also discussed the role of mitochondrion in the global cardiac metabolism. Transmission electron microscopy revealed that mitochondrial structural injury was invoked at 8 minutes post-coronary occlusion. In total, 75 metabolites in myocardium and 26 in mitochondria were screened out. About 23% of the differentiated metabolites in mitochondria overlapped with the differentiated metabolites in myocardium; Total 81% of the perturbed metabolic pathway in mitochondria overlapped with the perturbed pathway in myocardium, and these pathways accounted for 50% of the perturbed pathway in myocardium. Purine metabolism was striking and mechanically important. In conclusion, in the early ischemia, myocardium exacerbated metabolic remodeling. Mitochondrion was a contributor to the myocardial metabolic disorder. Purine metabolism may be a potential biomarker for early ischemia diagnosis. Our study introduced a perspective for prompt identification of ischemia.

Extensive mitochondrial proteome disturbance occurs during the early stages of acute myocardial ischemia.

Mitochondrial malfunction leads to the remodeling of myocardial energy metabolism during myocardial ischemia (MI). However, the alterations to the mitochondrial proteome profile during this period has not yet been clarified. An acute MI model was established by high position ligation of the left anterior descending artery in 8-week-old C57BL/6N mice. After 15 min of ligation, the animals were euthanized, and their hearts were collected. The myocardial ultrastructure was observed using transmission electron microscopy (TEM). The cardiac mitochondrial proteome profile was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and bioinformatics analyses. TEM showed that the outer membrane of the mitochondria was dissolved, and the inner membrane (cristae) was corrupted and broken down extensively in the MI group. The mitochondrial membrane potential was decreased. More than 1,700 mitochondrial proteins were identified by LC-MS/MS analysis, and 119 were differentially expressed. Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis showed that endopeptidase activity regulation, the mitochondrial inner membrane, oxidative phosphorylation, the hypoxia-inducible factor-1 signaling pathway, the pentose phosphate pathway and the peroxisome proliferator-activated receptor signaling pathway were involved in the pathophysiological process in the early stage of acute MI. Extensive and substantial changes in the mitochondrial proteins as well as mitochondrial microstructural damage occur in the early stages of acute MI. In the present study, the series of proteins crucially involved in the pathways of mitochondrial dysfunction and metabolism were identified. Further studies are needed to clarify the roles of these proteins in myocardial metabolism remodeling during acute MI injury.

[Astragaloside â £'s Therapeutic Effect on Myocardial Infarction via Affecting Autophagy and the Mechanism Study].

OBJECTIVE: The purpose of this study was to investigate the protective effect of astragaloside Ⅳ (AS-Ⅳ) on neonatal rats' hypoxic/reoxygenated (H/R) injured myocardial cells and to explore its underlying mechanism. METHODS: Cardiac cells were extracted from newborn rats and divided into control, H/R, H/R-low AS-Ⅳ (0.1 µmol/L AS-Ⅳ), H/R-medium AS-Ⅳ (1 µmol/L AS-Ⅳ), H/R-high AS-Ⅳ (10 µmol/L AS-Ⅳ) and H/R-high AS-Ⅳ-AKT (10 µmol/L AS-Ⅳ+5 µmol/L AKT) groups. After 48 h of treatment, the contents of LC3-Ⅱ, p62, AKT, pAKT, rapamycin (mTOR) mammalian targets and uncoordinated 51-like kinase 1 (ULK1) in cardiac myocytes were compared. Immunofluorescence staining was used to detect the expression of P62 in myocardium autophagosome. RESTULTS: AS-Ⅳ improved the proliferative activity of cardio AS-Ⅳ improved the proliferative activity of cardiomyocytes in H/R injury in a dose-dependent manner and inhibited the level of cell autophagy. However, when AKT inhibitors were added, the effect of AS-Ⅳ was partially inhibited ( P<0.05). Gene and protein expression showed that AS-Ⅳ had no significant effect on the expression of AKT and mTOR genes ( P>0.05), but could significantly promote the phosphorylation of AKT and mTOR ( P<0.05). Immunofluorescence staining results showed that high concentrations of the AS - Ⅳ can reverse H/R injury induced the expression of autophagy body P62. CONCLUSION: AS-Ⅳ showed protection effect on H/R injured myocardial cells. The possible mechanism is by reducing the autophagy level via activating the mTOR signal in the PI3K/AKT pathway, thereby preventing H/R damage in neonatal rat cardiomyocytes.