mROS­calcium feedback loop promotes lethal ventricular arrhythmias and sudden cardiac death in early myocardial ischemia.

Lethal ventricular arrhythmia­sudden cardiac death (LVA­SCD) occurs frequently during the early stage of myocardial ischemia (MI). However, the mechanism underlying higher LVA­SCD incidence is still poorly understood. The present study aimed to explore the role of mitochondrial reactive oxygen species (mROS) and Ca2+ crosstalk in promoting LVA­SCD in early MI. RyR2 S2814A mice and their wild­type littermates were used. MitoTEMPO was applied to scavenge mitochondrial ROS (mROS). Mice were subjected to severe MI and the occurrence of LVA­SCD was evaluated. Levels of mitochondrial ROS and calcium (mitoCa2+), cytosolic ROS (cytoROS), and calcium (cytoCa2+), RyR2 Ser­2814 phosphorylation, CaMKII Met­282 oxidation, mitochondrial membrane potential (MMP), and glutathione/oxidized glutathione (GSH/GSSG) ratio in the myocardia were detected. Dynamic changes in mROS after hypoxia were investigated using H9c2 cells. Moreover, the myocardial phosphoproteome was analyzed to explore the related mechanisms facilitating mROS­Ca2+ crosstalk and LVA­SCD. There was a high incidence (~33.9%) of LVA­SCD in early MI. Mice who underwent SCD displayed notably elevated levels of myocardial ROS and mROS, and the latter was validated in H9c2 cells. These mice also demonstrated overloads of cytoplasmic and mitochondrial Ca2+, decreased MMP and reduced GSH/GSSG ratio, upregulated RyR2­S2814 phosphorylation and CaMKII­M282 oxidation and transient hyperphosphorylation of mitochondrial proteomes in the myocardium. mROS­specific scavenging by a mitochondria­targeted antioxidant agent (MitoTEMPO) corrected these SCD­induced alterations. S2814A mice with a genetically inactivated CaMKII phosphorylation site in RyR2 exhibited decreased overloads in cytoplasmic and mitochondrial Ca2+ and demonstrated similar effects as MitoTEMPO to correct SCD­induced changes and prevent SCD post­MI. The data confirmed crosstalk between mROS and Ca2+ in promoting LVA­SCD. Therefore, we provided evidence that there is a higher incidence of LVA­SCD in early MI, which may be attributed to a positive feedback loop between mROS and Ca2+ imbalance.

Integrating serum proteomics and metabolomics to compare the common and distinct features between acute aggressive ischemic stroke (APIS) and acute non-aggressive ischemic stroke (ANPIS).

Understanding common and distinct pathophysiological features between acute progressive ischemic stroke (APIS) and acute non-progressive ischemic stroke (ANPIS) is a prerequisite to making clear the mechanism to determine the prognosis of acute ischemic stroke (AIS). Here, we recruited three independent sets of subjects, all of which included the APIS, ANPIS, and control groups. They were used for serum proteomic and metabolomic analyses, and validation of the critical pathophysiological processes and potential biomarkers of APIS, respectively. Results showed that there were both common and distinct metabolome and proteome between APIS and ANPIS. APIS and ANPIS shared basic processes of AIS in inflammation and oxidative stress response. Coagulation and lipid metabolism disorder, activation of the complement system, and inflammation may enhance with each other in the symptom worsening of APIS. The contents of serum amyloid A1 (SAA1) and S100 calcium-binding protein A9 (S100-A9) in the validation set confirmed the key pathophysiological processes indicated by omics data; they also jointly conferred a moderate value to distinguish APIS from ANPIS. Collectively, disturbance in coagulation and lipid metabolism, complement activation, and inflammation may be synergistically involved in symptom deterioration in APIS. SAA1 and S100-A9 serve as a potential biomarker panel to distinguish APIS from ANPIS. THE SIGNIFICANCE: In this study, we integrated serum proteomics and metabolomics to explore the similarities and differences in pathophysiological processes between APIS and ANPIS. The global metabolic networks have been constructed, and the crucial common pathophysiological processes and the key distinct pathophysiological features between APIS and ANPIS were investigated based on the differentially expressed proteins and metabolites (DEPs/DEMs). Furthermore, pivotal serum proteins (SAA1 and S100A9) were detected in a dependent set to validate the key pathophysiological characteristics, as well as to assess the possibility of them being used as a biomarker panel. Taken together, the multi-omics integration strategy used in this clinical study shows potential to comprehensively interpret and compare the pathophysiological processes of AIS in various conditions, as well as to screen a reliable new biomarker panel.

Serum metabolic characteristics and biomarkers of early-stage heart failure.

Aim: We aimed to identify metabolic characteristics of early-stage heart failure (HF) and related biomarkers. Patients & methods: One hundred and forty-three patients with New York Heart Association class I-IV HF and 34 healthy controls were recruited. Serum metabolic characteristics of class I HF were analyzed and compared with those of class II-IV HF. Potential biomarkers of class I HF with normal N-terminal-pro-B-type natriuretic peptide (NT-proBNP) level were screened and validated in additional 72 subjects (46 class I patients and 26 controls). Results & conclusion: Eleven metabolites were found disturbed in class I HF, and five of which were also disturbed in class II-IV HF. Glutamine and tyrosine showed high value to identify class I HF with normal NT-proBNP level. The diagnostic potential of glutamine was partially confirmed in the validate set, holding a promise to detect early HF with normal NT-proBNP level.

GC-MS-based metabolomics identifies an amino acid signature of acute ischemic stroke.

Ischemic stroke is a serious public health problem worldwide. Here, we characterized the metabolite features of acute ischemic stroke (AIS) using a gas chromatography-mass spectrometry-based metabolomics. Forty AIS patients and 29 sex and age-matched controls were recruited. The serum metabolic profiles were significantly different between the two groups. Compared to the controls, the patients had elevated levels of lactate, carbonate and glutamate (P<0.01), and lowered levels of alanine, citrate, glycine, isoleucine, leucine, serine, tyrosine, methionine, tryptophan, erythronic acid, urea, purine, hypoxanthine, and proline in the serum (P<0.05). Amino acids are the most important disturbed metabolites. Most dysregulated metabolites are closely correlated with each other and with several biochemical indices. The differential metabolites reflect pathophysiological processes of inflammation, energy deficit, oxidative stress, neurotoxicity, neuro excitation and injury. Tyrosine, lactate, and tryptophan were screened as a panel of potential biomarkers of AIS, jointly enabling a high precision (91.7%) to diagnose AIS by classification and regression tree (CRT). Collectively, we discovered a marked perturbation of metabolome of AIS in the serum, mainly associated with amino acid-related metabolism. Tyrosine, lactate, and tryptophan may be considered as potential biomarkers of AIS.

GC-MS-Based metabolomics discovers a shared serum metabolic characteristic among three types of epileptic seizures.

OBJECTIVE: Understanding the overall and common metabolic changes of seizures can provide novel clues for their control and prevention. Here, we aim to investigate the global metabolic feature of serum for three types of seizures. METHODS: We recruited 27 patients who had experienced a seizure within 48h (including 11 who had a generalized seizure, nine who had a generalized seizure secondary to partial seizure and seven who had a partial seizure) and 23 healthy controls. We analyzed the global metabolic changes of serum after seizures using gas chromatography-mass spectrometry-based metabolomics. Based on differential metabolites, the metabolic pathways and their potential to diagnose seizures were analyzed, and metabolic differences among three types of seizures were compared. RESULTS: The metabolic profiles of serum were distinctive between the seizure group and the controls but were not different among the three types of seizures. Compared to the controls, patients with seizures had higher levels of lactate, butanoic acid, proline and glutamate and lower levels of palmitic acid, linoleic acid, elaidic acid, trans-13-octadecenoic acid, stearic acid, citrate, cysteine, glutamine, asparagine, and glyceraldehyde in the serum. Furthermore, these differential metabolites had common change trends among the three types of seizures. Related pathophysiological processes reflected by these metabolites are energy deficit, inflammation, nervous excitation and neurotoxicity. Importantly, transamination inhibition is suspected to occur in seizures. Lactate, glyceraldehyde and trans-13-octadecenoic acid in serum jointly enabled a precision of 92.9% for diagnosing seizures. CONCLUSIONS: There is a common metabolic feature in three types of seizures. Lactate, glyceraldehyde and trans-13-octadecenoic acid levels jointly enable high-precision seizure diagnosis.

Small Molecule Copper and Its Relative Metabolites in Serum of Cerebral Ischemic Stroke Patients.

BACKGROUND: Copper is a strong pro-oxidant. The most important pro-oxidative form in serum is small molecule copper (SMC), which is copper that is loosely bound to small molecules, such as amino acids and polypeptides. The association between copper and atherosclerotic diseases has been confirmed, but that between SMC and cerebral ischemic stroke (CIS), one of the most principal manifestations and causes of death of atherosclerotic disease, is not yet clear. METHODS: We recruited 45 CIS patients and 25 age- and gender-matched healthy controls. We detected their serum levels of SMC, total copper, homocysteine (Hcy), and ceruloplasmin (CP), as well as urinary total copper, and analyzed the relationship of SMC with these aforementioned metabolites or compounds in CIS patients. RESULTS: SMC was 4.2 ± .5 µg/L and 2.1 ± .9 µg/L; total copper in sera was 1345.5 ± 308.2 µg/L and 1180.3 ± 134.0 µg/L; and total copper in urine was 27.6 ± 9.3 µg/L and 18.8 ± 8.1 µg/L in patients and controls, respectively (all P < .05). Serum CP activity in CIS patients was 59.92 ± 12.11 U/L versus 37.76 ± 5.71 U/L in controls (P = .0001). The concentration of SMC was positively correlated with CP activity, Hcy concentration in sera, and urinary total copper. CONCLUSION: The serum level of SMC and total copper is remarkably elevated, and SMC positively correlates with Hcy, CP activity, and urinary total copper in CIS patients.