Plasma proteomics implicate glutamic oxaloacetic transaminases as potential markers for acute myocardial infarction

AIM

To provide a novel perspective on the pathogenesis of acute myocardial infarction (AMI) patients with respect to glutamic oxaloacetic transaminase (GOT).

METHODS

The plasma proteome of 20 patients with AMI were matched for age and sex and compared with 10 healthy individuals. We analyzed the mass spectrum data and compared the signal intensity of the corresponding peptides which related to their corresponding proteins. A sample-specific protein database was constructed and a quality control analysis was conducted to screen out the key regulatory proteins under specific experimental conditions. The data from 37 new AMI patients and 13 healthy adults were subjected to parallel reaction monitoring (PRM) to verify the target proteins found. Finally, the survival status of the key genes (> 1.5-fold) in the PPI were analyzed.

RESULTS

2589 and 2162 proteins were identified and quantified, respectively, and 143 differentially expressed proteins (DEPs) (≥1.5-fold) were found between the AMI and control groups. Of these 90 and 53 were significantly up-regulated and down-regulated, respectively. Gene ontology, KEGG enrichment, protein domain and cluster analysis as well as PPI networks of the DEPs revealed a central role of acute inflammatory response processes in patients with AMI. A cluster of proteins were found to be related to cysteine, methionine, arginine, proline, phenylalanine and propanoate metabolism as well as the cAMP signaling pathway. PPI network analysis showed CHI3L1, COPB2, GOT2, MB, CYCS, GOT1, CKM, SAA1 and PRKCD and RPS3 were in key positions, but only MB, CKM, GOT1, PRKCD, CYCS and GOT2 were found in a cluster. PRM verified the high levels of MB, CKM, GOT1 and GOT2 in 37 AMI patients but there was no statistical difference in the survival status for patients with either high or low expression levels of these proteins.

CONCLUSIONS

Our findings showed that acute inflammatory response processes play a central role in patients with AMI. Cysteine and methionine metabolism was also activated, in which GOT1 and GOT2 were key proteins. These pathways might be potential targets for diagnosis and novel therapies to improve the poor outcomes observed in patients with heart failure.

SGLT-2 inhibitors in chronic peritoneal dialysis patients: a follow-up study

BACKGROUND

Sodium-glucose transporter-2 inhibitors (SGLT-2i) are recommended for use in patients with type 2 diabetes comorbid atherosclerotic cardiovascular disease, heart failure, or chronic kidney disease. Limited reports are currently available for their use in dialysis patients. In an observational, retrospective follow-up study, we reported the clinical characteristics of chronic peritoneal dialysis (PD) patients on SGLT-2i.

METHODS

We enrolled 50 diabetic chronic PD patients, and 11 continued SGLT-2i after PD treatment. We reported the patients' ultrafiltration, HbA1c, urinary tract infection episodes, and venous CO2 during follow-up and compared the differences in these factors between patients with and without SGLT-2i.

RESULTS

The mean age of the patients was 65 ± 15 years, and 16 (32%) patients were female. The age, gender, heart failure, and primary kidney disease were not different between patients with and without SGLT-2i at enrollment. In an average of 31 months follow-up, patients with SGLT-2i had higher ultrafiltration (1322 ± 200 ml/day vs. 985 ± 415 ml/day, p = 0.013), hemoglobin (11.2 ± 1.7 vs. 10.2 ± 1.7 g/dl), white blood cell count (9.2 ± 3.7 vs. 7.4 ± 2.1 109/L), and a lower venous CO2 (p = 0.036). The urine amount, the overall survival, the technical survival, and the chance of UTI were not different between patients with and without SGLT2i.

CONCLUSION

SGLT-2i may increase ultrafiltration volume and hemoglobin levels in chronic PD patients. SGLT-2i did not increase urinary tract infection but was linked to subclinical metabolic acidosis.

WHAT WAS KNOWN

The effect of SGLT-2i in chronic PD patients is not clear?

THIS STUDY ADDS

SGLT-2i is associated with increased ultrafiltration, hemoglobin, white blood cell counts, and a decreased CO2 in PD patient.

POTENTIAL IMPACT

SGLT-2i may increase ultrafiltration in PD patients.

Sex-related differences in plasma amino acids of patients with ST-elevation myocardial infarction and glycine as risk marker of acute heart failure with preserved ejection fraction

Nowadays, the problem of preventing acute heart failure (AHF) in patients with ST-elevation myocardial infarction (STEMI) and preserved left-ventricular ejection fraction (pLVEF) is still not completely resolved, especially in late-presented patients. The purpose of study was: (1) assessment of free plasma amino acid (PAA) alterations in STEMI patients [not receiving reperfusion therapy (RT)], depending on sex and LVEF; (2) analysis of development of late/persistent AHF more than 48 h after admission (pAHF) in STEMI patients with pLVEF depending on PAA levels. This prospective cohort study included 92 STEMI patients (33 women and 59 men), not receiving RT. The free PAA were investigated by ion-exchange liquid-column chromatography. The women had significantly higher PAA levels than men in general cohort and cohort with pLVEF (n = 69). There were associations between female sex and pAHF in general cohort (OR 3.7, p = 0.004) and cohort with pLVEF (OR 11.4, p = 0.0001) by logistic regression. The association between pAHF and glycine level [OR 2.5, p < 0.0001; AUC 0.84, p < 0.0001; 86.7% sensitivity and 77.8% specificity for > 2.6 mg/dL] was revealed in cohort with pLVEF (including female and male). Glycine remained a predictor of pAHF with pLVEF by multivariable logistic regression adjusting for comorbidities, demographic and clinical variables. Higher rate of pAHF in female than in male STEMI patients with pLVEF is associated with higher plasma glycine in women. The glycine level may be genetically determinated by female sex. The plasma glycine > 2.6 mg/dL is a predictor of pAHF in STEMI with pLVEF (including female and male).

Lead (Pb) exposure and heart failure risk

Lead (Pb) is a heavy metal with widespread industrial use, but it is also a widespread environmental contaminant with serious toxicological consequences to many species. Pb exposure adversely impacts the cardiovascular system in humans, leading to cardiac dysfunction, but its effects on heart failure risk remain poorly elucidated. To better understand the pathophysiological effects of Pb, we review potential mechanisms by which Pb exposure leads to cardiac dysfunction. Adverse effects of Pb exposure on cardiac function include heart failure risk, pressure overload, arrhythmia, myocardial ischemia, and cardiotoxicity. The data reviewed clearly establish that Pb exposure can play an important role in the occurrence and development of heart failure. Future epidemiological and mechanistic studies should be developed to better understand the involvement of Pb exposure in heart failure.

Relationship between serum homocysteine levels and long-term outcomes in patients with ST-segment elevation myocardial infarction

BACKGROUND

The mortality of cardiovascular disease is constantly rising, and novel biomarkers help us predict residual risk. This study aimed to evaluate the predictive value of serum homocysteine (HCY) levels on prognosis in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

The 419 consecutive patients with STEMI, treated at one medical center, from March 2010 to December 2015 were retrospectively investigated. Peripheral blood samples were obtained within 24 h of admission and HCY concentrations were measured using an enzymatic cycling assay. The patients were divided into high HCY level (H-HCY) and low HCY level (L-HCY) groups. Short- and long-term outcomes were compared, as were age-based subgroups (patients aged 60 years and younger vs. those older than 60 years). Statistical analyses were mainly conducted by Student t-test, Chi-squared test, logistic regression, and Cox proportional-hazards regression.

RESULTS

The H-HCY group had more males (84.6% vs. 75.4%, P = 0.018), and a lower prevalence of diabetes (20.2% vs. 35.5%, P < 0.001), compared with the L-HCY group. During hospitalization, there were seven mortalities in the L-HCY group and 10 in the H-HCY group (3.3% vs. 4.8%, P = 0.440). During the median follow-up period of 35.8 (26.9-46.1) months, 33 (16.2%) patients in the L-HCY group and 48 (24.2%) in the H-HCY group experienced major adverse cardiovascular and cerebrovascular events (MACCE) (P = 0.120). History of hypertension (hazard ratio [HR]: 1.881, 95% confidence interval [CI]: 1.178-3.005, P = 0.008) and higher Killip class (HR: 1.923, 95% CI: 1.419-2.607, P < 0.001), but not HCY levels (HR: 1.007, 95% CI: 0.987-1.027, P = 0.507), were significantly associated with long-term outcomes. However, the subgroup analysis indicated that in older patients, HCY levels were significantly associated with long-term outcomes (HR: 1.036, 95% CI: 1.011-1.062, P = 0.005).

CONCLUSION

Serum HCY levels did not independently predict in-hospital or long-term outcomes in patients with STEMI; however, among elderly patients with STEMI, this study revealed a risk profile for late outcomes that incorporated HCY level.

Is hyperhomocysteinemia a causal factor for heart failure? The impact of the functional variants of MTHFR and PON1 on ischemic and non-ischemic etiology

BACKGROUND

Hyperhomocysteinemia was found to be uniformly associated with the development of heart failure (HF) and HF mortality; however, it is uncertain whether this relation is causative or not. We used Mendelian randomization to examine the associations of the methylene tetrahydrofolate gene (MTHFR) and paraoxonase 1 gene (PON1) variants as a proxy for lifelong exposure to high Hcy and Hcy-thiolactone concentrations with the development of HF in men aged ≤60years and the occurrence of adverse effects at one-year follow-up.

METHODS

The study enrolled 172 men with HF: 117 with ischemic etiology (iHF) related to coronary artery disease (CAD) and 55 with non-ischemic etiology (niHF) related to dilated cardiomyopathy (DCM). The reference group of 329 CAD patients without HF and the control group of 384 men were also analyzed.

RESULTS

Hyperhomocysteinemia (OR=2.0, P<0.05) and the MTHFR 677TT/1298AA, 677CC/1298CC genotypes (OR=1.6, P=0.03) were associated with HF regardless of its etiology, especially among normotensives (OR=4.6, P=0.001 and OR=2.3, P=0.003, respectively). In niHF, the PON1 162AA (OR=2.3, P=0.03) and 575AG+GG (OR=0.46, P=0.01) genotypes also influenced the risk. The interaction between HDLC<1mmol/L and the PON1 575GG genotype was found to influence the risk of iHF (OR=7.2, P=0.009). Hyperhomocysteinemia improved the classification of niHF patients as 'high-risk' by 10.1%. Ejection fraction <30% and DCM increased the probability of HF death or re-hospitalization within one year.

CONCLUSION

Our results provide evidence that hyperhomocysteinemia is a causal factor for niHF in DCM, while dysfunctional HDL could contribute to the pathogenesis of iHF.

Methoxistasis: integrating the roles of homocysteine and folic acid in cardiovascular pathobiology

Over the last four decades, abnormalities in the methionine-homocysteine cycle and associated folate metabolism have garnered great interest due to the reported link between hyperhomocysteinemia and human pathology, especially atherothrombotic cardiovascular disease. However, clinical trials of B-vitamin supplementation including high doses of folic acid have not demonstrated any benefit in preventing or treating cardiovascular disease. In addition to the fact that these clinical trials may have been shorter in duration than appropriate for modulating chronic disease states, it is likely that reduction of the blood homocysteine level may be an oversimplified approach to a complex biologic perturbation. The methionine-homocysteine cycle and folate metabolism regulate redox and methylation reactions and are, in turn, regulated by redox and methylation status. Under normal conditions, a normal redox-methylation balance, or “methoxistasis”, exists, coordinated by the methionine-homocysteine cycle. An abnormal homocysteine level seen in pathologic states may reflect a disturbance of methoxistasis. We propose that future research should be targeted at estimating the deviation from methoxistasis and how best to restore it. This approach could lead to significant advances in preventing and treating cardiovascular diseases, including heart failure.

Emerging families of biomarkers for coronary artery disease: inflammatory mediators

Introduction

Inflammation has been implicated in the development of atherosclerosis in patients with acute coronary syndrome. C-reactive protein is an established nonspecific prognostic inflammatory biomarker for patients with acute coronary syndrome in the medical literature. This has led to a concerted effort to identify circulating inflammatory biomarkers to facilitate predicting the risk for and diagnosing coronary artery disease in at-risk subjects. The objective of this study was to search after novel inflammatory biomarkers reported as useful for diagnosing coronary artery disease.

Methods

The PubMed database was searched for reports published from January 1, 2000 to June 30, 2012 of novel circulating biomarkers for coronary artery disease in addition to the established biomarker, C-reactive protein. The search terms used were “infarction”, “biomarkers”, and “markers”, and only original articles describing clinical trials that were written in English were included. All published articles were separately examined carefully after novel inflammatory markers for acute coronary syndrome. All irrelevant publications without content pertaining to inflammatory biomarkers for acute coronary syndrome were excluded from this study. Our results reflect all articles concerning biomarkers in humans.

Results

The PubMed search yielded 4,415 research articles. After further analysis, all relevant published original articles examining 53 biomarkers were included in this review, which identified 46 inflammation biomarkers useful for detecting coronary artery disease.

Conclusion

The emergence of diverse novel biomarkers for coronary artery disease has provided insight into the varied pathophysiology of this disease. Inflammatory biomarkers have tremendous potential in aiding the prediction of acute coronary syndrome and recurrent ischemic episodes, and will eventually help improve patient care and management.

Analysis of factors related to short-term prognosis in patients undergoing percutaneous coronary intervention for acute myocardial infarction

The present study aimed to investigate the factors related to short-term prognosis in patients undergoing direct percutaneous coronary intervention (PCI) for acute ST-segment elevation myocardial infarction (STEMI). A total of 805 patients were included and divided into a control group and an adverse cardiovascular events group based on the prognosis, to compare risk factors and coronary angiographic characteristics in the two groups. In the adverse events group, the ages, admission blood glucose, uric acid (UA), homocysteine (HCY), creatine kinase (CK) and peak creatine kinase-MB (CKMB) isozyme levels were clearly higher compared with those in the control group, while the levels of total cholesterol (TC), triglycerides (TGs) and low-density lipoprotein (LDL) were lower compared with those in the control group. The incidence of hypertension in females in the adverse events group was markedly higher compared with that in the control group, while the diabetes rate was lower compared with that in the control group. Logistic regression analysis revealed that age, gender, hypertension, diabetes and admission blood glucose, HCY, TC and UA levels were independent risk factors of short-term prognosis in patients undergoing emergency PCI. The majority of the patients in the adverse events group were elderly females with hypertension, a large area of myocardial infarction and increased admission blood glucose, UA and HCY levels, as well as a low diabetes rate and decreased levels of acute-phase TC and LDL.

Myocardium proteome remodelling after nutritional deprivation of methyl donors

Methyl donor (MD: folate, vitamin B12 and choline) deficiency causes hyperhomocysteinemia, a risk factor for cardiovascular diseases. However, the mechanisms of the association between MD deficiency, hyperhomocysteinemia, and cardiomyopathy remain unclear. Therefore, we performed a proteomic analysis of myocardium of pups from rat dams fed a MD-depleted diet to understand the impact of MD deficiency on heart at the protein level. Two-dimension gel electrophoresis and mass spectrometry-based analyses allowed us to identify 39 proteins with significantly altered abundance in MD-deficient myocardium. Ingenuity Pathway Analysis showed that 87% of them fitted to a single protein network associated with developmental disorder, cellular compromise and lipid metabolism. Concurrently increased protein carbonylation, the major oxidative post-translational protein modification, could contribute to the decreased abundance of many myocardial proteins after MD deficiency. To decipher the effect of MD deficiency on the abundance of specific proteins identified in vivo, we developed an in vitro model using the cardiomyoblast cell line H9c2. After a 4-day exposure to a MD-deprived (vs. complete) medium, cells were deficient of folate and vitamin B12, and released abnormal amounts of homocysteine. Western blot analyses of pup myocardium and H9c2 cells yielded similar findings for several proteins. Of specific interest is the result showing increased and decreased abundances of prohibitin and α-crystallin B, respectively, which underlines mitochondrial injury and endoplasmic reticulum stress within MD deficiency. The in vitro findings validate the MD-deficient H9c2 cells as a relevant model for studying mechanisms of the early metabolic changes occurring in cardiac cells after MD deprivation.