Discovery of potential plasma protein biomarkers for acute myocardial infarction via proteomics

Prior Exposure to Experimental Preeclampsia Increases Atherosclerotic Plaque Inflammation in Atherogenic Mice-Brief Report

BACKGROUND

Women with a history of preeclampsia have evidence of premature atherosclerosis and increased risk of myocardial infarction and stroke compared with women who had a normotensive pregnancy. Whether this is due to common risk factors or a direct impact of prior preeclampsia exposure has never been tested in a mouse atherosclerosis model.

METHODS

Pregnant LDLR-KO (low-density lipoprotein receptor knockout; n=35) female mice were randomized in midgestation to sFlt1 (soluble fms-like tyrosine kinase 1)-expressing adenovirus or identical control adenovirus. Postpartum, mice were fed high-fat diet for 8 weeks to induce atherogenesis. Comparison between the control and preeclampsia models was made for metabolic parameters, atherosclerosis burden and composition by histology, plaque inflammation by flow cytometry, and aortic cytokines and inflammatory markers using a cytokine array.

RESULTS

In pregnant LDLR-KO mice, sFlt1 adenovirus significantly induced serum sFlt1, blood pressure, renal endotheliosis, and decreased pup viability. After 8 weeks of postpartum high fat feeding, body weight, fasting glucose, plasma cholesterol, HDL (high-density lipoprotein), and LDL (low-density lipoprotein) were not significantly different between groups with no change in aortic root plaque size, lipid content, or necrotic core area. Flow cytometry demonstrated significantly increased CD45+ aortic arch leukocytes and CD3+T cells and aortic lysate contained more CCL (CC motif chemokine ligand) 22 and fetuin A and decreased expression of IGFBP6 (insulin-like growth factor-binding protein 6) and CCL21 in preeclampsia-exposed mice compared with controls.

CONCLUSIONS

In atherogenic LDLR-KO mice, exposure to sFlt1-induced preeclampsia during pregnancy increases future atherosclerotic plaque inflammation, supporting the concept that preeclampsia directly exacerbates atherosclerotic inflammation independent of preexisting risk factors. This mechanism may contribute to ischemic vascular disease in women after preeclampsia pregnancy.

Discovery of plasma proteins associated with ventricular fibrillation during first ST-elevation myocardial infarction via proteomics

AIMS

The underlying biological mechanisms of ventricular fibrillation (VF) during acute myocardial infarction are largely unknown. To our knowledge, this is the first proteomic study for this trait, with the aim to identify and characterize proteins that are associated with VF during first ST-elevation myocardial infarction (STEMI).

METHODS AND RESULTS

We included 230 participants from a Danish ongoing case-control study on patients with first STEMI with VF (case, n = 110) and without VF (control, n = 120) before guided catheter insertion for primary percutaneous coronary intervention. The plasma proteome was investigated using mass spectrometry-based proteomics on plasma samples collected within 24 h of symptom onset, and one patient was excluded in quality control. In 229 STEMI patients {72% men, median age 62 years [interquartile range (IQR): 54-70]}, a median of 257 proteins (IQR: 244-281) were quantified per patient. A total of 26 proteins were associated with VF; these proteins were involved in several biological processes including blood coagulation, haemostasis, and immunity. After correcting for multiple testing, two up-regulated proteins remained significantly associated with VF, actin beta-like 2 [ACTBL2, fold change (FC) 2.25, P < 0.001, q = 0.023], and coagulation factor XIII-A (F13A1, FC 1.48, P < 0.001, q = 0.023). None of the proteins were correlated with anterior infarct location.

CONCLUSION

Ventricular fibrillation due to first STEMI was significantly associated with two up-regulated proteins (ACTBL2 and F13A1), suggesting that they may represent novel underlying molecular VF mechanisms. Further research is needed to determine whether these proteins are predictive biomarkers or acute phase response proteins to VF during acute ischaemia.

Proteomic analysis of plasma proteins from patients with cardiac rupture after acute myocardial infarction using TMT-based quantitative proteomics approach

BACKGROUND

Cardiac rupture (CR) is a rare but catastrophic mechanical complication of acute myocardial infarction (AMI) that seriously threatens human health. However, the reliable biomarkers for clinical diagnosis and the underlying signaling pathways insights of CR has yet to be elucidated.

METHODS

In the present study, a quantitative approach with tandem mass tag (TMT) labeling and liquid chromatography-tandem mass spectrometry was used to characterize the differential protein expression profiles of patients with CR. Plasma samples were collected from patients with CR (n = 37), patients with AMI (n = 47), and healthy controls (n = 47). Candidate proteins were selected for validation by multiple reaction monitoring (MRM) and enzyme-linked immunosorbent assay (ELISA).

RESULTS

In total, 1208 proteins were quantified and 958 differentially expressed proteins (DEPs) were identified. The difference in the expression levels of the DEPs was more noticeable between the CR and Con groups than between the AMI and Con groups. Bioinformatics analysis showed most of the DEPs to be involved in numerous crucial biological processes and signaling pathways, such as RNA transport, ribosome, proteasome, and protein processing in the endoplasmic reticulum, as well as necroptosis and leukocyte transendothelial migration, which might play essential roles in the complex pathological processes associated with CR. MRM analysis confirmed the accuracy of the proteomic analysis results. Four proteins i.e., C-reactive protein (CRP), heat shock protein beta-1 (HSPB1), vinculin (VINC) and growth/differentiation factor 15 (GDF15), were further validated via ELISA. By receiver operating characteristic (ROC) analysis, combinations of these four proteins distinguished CR patients from AMI patients with a high area under the curve (AUC) value (0.895, 95% CI, 0.802-0.988, p < 0.001).

CONCLUSIONS

Our study highlights the value of comprehensive proteomic characterization for identifying plasma proteome changes in patients with CR. This pilot study could serve as a valid foundation and initiation point for elucidation of the mechanisms of CR, which might aid in identifying effective diagnostic biomarkers in the future.

A Mass Spectrometry-Based Proteome Study of Twin Pairs Discordant for Incident Acute Myocardial Infarction within Three Years after Blood Sampling Suggests Novel Biomarkers

Acute myocardial infarction (AMI) is a major cause of mortality and morbidity worldwide, yet biomarkers for AMI in the short- or medium-term are lacking. We apply the discordant twin pair design, reducing genetic and environmental confounding, by linking nationwide registry data on AMI diagnoses to a survey of 12,349 twins, thereby identifying 39 twin pairs (48-79 years) discordant for their first-ever AMI within three years after blood sampling. Mass spectrometry of blood plasma identified 715 proteins. Among 363 proteins with a call rate > 50%, imputation and stratified Cox regression analysis revealed seven significant proteins (FDR < 0.05): FGD6, MCAM, and PIK3CB reflected an increased level in AMI twins relative to their non-AMI co-twins (HR > 1), while LBP, IGHV3-15, C1RL, and APOC4 reflected a decreased level in AMI twins relative to their non-AMI co-twins (HR < 1). Additional 50 proteins were nominally significant (p < 0.05), and bioinformatics analyses of all 57 proteins revealed biology within hemostasis, coagulation cascades, the immune system, and the extracellular matrix. A protein-protein-interaction network revealed Fibronectin 1 as a central hub. Finally, technical validation confirmed MCAM, LBP, C1RL, and APOC3. We put forward novel biomarkers for incident AMI, a part of the proteome field where markers are surprisingly rare and where additional studies are highly needed.

Common and specific proteins and pathways in heart and cerebral ischemia

OBJECTIVE

To understand the similarities and differences between acute ischemic stroke and acute myocardial infarction (AMI) to help in the development of specific or common treatment strategies.

METHODS

Using an aptamer-based proteomic array, we measured and compared 1310 circulating proteins in the blood of 40 patients with AIS, 9 patients with AMI, and 31 healthy controls. Pathway enrichment analysis was performed using GSEA and g:profiler.

RESULTS

Ninety-four proteins were differentially expressed in AIS, and 284 were differentially expressed in AMI. Of these, 8 were specific to cerebral ischemia, and 197 were specific to myocardial infarction. Forty-two proteins were altered in both ischemia processes. Most altered pathways in AIS could be classified as immune response, cell cycle processing, molecular transport, or signaling. Pathways altered in AMI were mostly related to lipid metabolism and transport, highlighting cholesterol metabolic processes and estrogen signaling. In both types of ischemia, we found pathways related to metabolism, specifically purine metabolism, and signaling processes, such as TNF signaling or MAPK1/3.

CONCLUSIONS

The present study revealed proteins and pathways that were specifically altered in cerebral ischemia, in cardiac ischemia, or in both diseases, providing information on the similarities and differences of ischemic conditions. The role of common and specific proteins and pathways should be explored in detail to find possible therapeutic targets.

Role of serum CAP1 protein in the diagnosis of patients with first-time acute myocardial infarction

The dysregulation of adenylate cyclase-associated protein 1 (CAP1) is associated with a variety of inflammatory conditions. Here, we aimed to assess the role of serum CAP1 protein in predicting acute myocardial infarction (AMI), and to explore its effect and mechanism in vascular endothelial cells injury. ELISA was utilized to detected CAP1 protein expression in serum from 70 patients with first-time AMI at 0, 6, 12, 24, 48 hours and 7 days of the onset of chest pain. Receiver operating characteristic (ROC) curve analysis was administered to analyze the diagnostic power of CAP1 for AMI. The CCK-8 and 5-BrdU assays were applied to measure cell proliferation and inflammation in a model of oxidized low-density lipoprotein (ox-LDL) induced human umbilical vein endothelial cells (HUVEC). Luciferase reporter gene assay and Western blotting were used to assess the activity of NF-κB pathway. Results showed that serum CAP1 protein expression was upregulated in patients with first-time AMI, its expression was highest at 12 hours of the onset of chest pain. CAP1 protein was positively associated with the levels of cTnI and ox-LDL. CAP1 showed a relatively high diagnostic accuracy in patients with first-time AMI compared with cTnI, and CAP1 combined with cTnI had superior diagnostic value than CAP1 and cTnI alone. The expression of CAP1 protein was increased in supernatants of ox-LDL induced HUVEC in a dose- and time-dependent manner. CAP1 inhibited cell proliferation but promoted inflammation, and induced the activation of NF-κB pathway in vitro. To sum up, increased serum CAP1 expression might serve as a novel diagnostic biomarker for patients with first-time AMI, the mechanism might be related to its induction of NF-κB pathway activation causing abnormal proliferation and inflammation and thus mediating vascular endothelial cell injury.

Identification of novel candidate biomarkers for acute myocardial infarction by the Olink proteomics platform

BACKGROUND

Both pathological and normal processes depend on proteins. In this study, plasma protein profiles were analyzed by a novel proximity extension assay (PEA) to identify potential pathogenic mechanisms and diagnostic biomarkers in patients diagnosed with acute myocardial infarction (AMI).

METHODS

In this study, we identified a total of 92 plasma proteins using the Olink Target 96 Cardiovascular III panel in a cohort consisting of 30 healthy controls (HC), 28 patients with unstable angina (UA) and 30 patients with AMI. Subsequently, we conducted a differential expression analysis to identify protein molecules that were specifically expressed in patients with AMI. To gain insights into the potential functional mechanisms of these differentially expressed molecules, we performed Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Following that, the utilization of least absolute shrinkage and selection operator (LASSO) regression facilitated the identification of potential protein biomarkers, enabling the differentiation between AMI and UA. A diagnostic model was subsequently developed through logistic regression, and the effectiveness of these markers was assessed using receiver operating characteristic (ROC) analysis. Ultimately, the diagnostic capabilities of these potential biomarkers were validated in an independent validation cohort consisting of 30 UA cases and 30 AMI cases.

RESULTS

In this study, a comprehensive analysis of plasma proteins identified a total of 92 proteins. Further analysis using analysis of variance revealed that 25 proteins exhibited specific expression in the AMI group compared to the HC and UA groups. Additionally, KEGG enrichment analysis indicated that these differentially expressed proteins were primarily associated with the activation of cytokine-cytokine receptor interaction, PI3K-Akt signaling pathway, and GnRH signaling pathway. AGRP, TGM2, IL6, GH1, and CA5A were identified through LASSO regression as prospective protein biomarkers for distinguishing between UA and AMI. The diagnostic model comprising these five proteins exhibited exceptional performance in both the discovery and validation datasets, surpassing AUC values of 0.9.

CONCLUSION

The findings of our study provide additional insights into the involvement of the inflammatory response and AKT cascade response in the development of AMI. Moreover, we have identified potential protein markers that could be utilized for the accurate diagnosis of AMI. These results offer a fresh perspective for clinical decision-making in the context of AMI.

Various Expressions of PIK3C2A and TXNIP Genes and Their Potential Role as Independent Risk Factors for Chronic Stable Angina and Acute Coronary Syndrome

BACKGROUND AND AIM

Genetic factors play a significant role in the onset and progression of coronary artery disease (CAD). PIK3C2A may contribute to the development of acute coronary syndrome (ACS) by affecting blood glucose levels and oxidative stress. The expression levels of TXNIP were significantly higher in patients with unstable angina pectoris. However, the situation is different in ACS. In the current study, we aim to investigate the role of PIK3C2A and TXNIP as independent risk factors for chronic stable angina (CSA) and ACS.

SUBJECTS AND METHODS

This study involved 215 subjects (60 patients with CSA, 55 patients with ACS, and 100 controls). All subjects were exposed for assaying gene expressions of PIK3C2A and TXNIP by quantitative real-time polymerase chain reaction.

RESULTS

It was found that TXNIP was upregulated, whereas PIK3C2A was downregulated in patients with CAD compared to the control group. PIK3C2A was significantly downregulated in patients with ACS compared to that in patients with CSA (p < 0.001), but TXNIP was not (p = 0.7). TXNIP was significantly upregulated in STEMI-ACS patients compared to CSA (p = 0.045) and NSTEMI ACS (p = 0.046), among non-diabetic (p = 0.023) smokers (p = 0.036) with hypertension (p = 0.005) and hypercholesterolemia (p = 0.001). ROC (receiver operating characteristic) curve analysis revealed that PIK3C2A (0.981; p < 0.001; 98.18) was the most sensitive mRNA for discriminating ACS from control, followed by TXNIP (0.775; p < 0.001; 70.91). However, for discriminating ACS from CSA combined mRNAs, (PIK3C2A + TXNIP) (0.893; p < 0.001; 98.18) and PIK3C2A (0.892; p < 0.001; 81.82) are promising biomarkers. On the other hand, the most sensitive mRNA for differentiating CSA from control is mRNAs (PIK3C2A + TXNIP) (0.963; p < 0.001; 95), then TXINP (81.3; p < 0.001; 93.33), and finally, PIK3C2A (0.782; p < 0.001; 81.67). In the multivariate regression model, PIK3C2A ((p = 0.002), 0.118 (0.031-0.445)) and smoking status ((p = 0.034); 0.151 (0.026-0.866)) were independent variables for ACS. Moreover, PIK3C2A ((p < 0.013); 0.706 (0.614-0.812)), Hb ((p = 0.013); 0.525 (0.317-0.871)), and total cholesterol ((p = 0.04); 0.865 (0.784-0.955)) were significantly (p < 0.05) and independently related to the prognosis of CSA. Furthermore, PIK3C2A ((p = 0.002), 0.923 (0.877-0.971)), TXNIP ((p = 0.001); 2.809 (1.558-5.064)) the body weight ((p = 0.033); 1.254 (1.018-1.544)) were independently associated with CSA.

CONCLUSIONS

Our study concluded that the dysregulated mRNA PIK3C2A and TXNIP gene expressions may be useful in diagnosis of CAD and prediction of ACS development.

Curcumin nanoemulsion counteracts hepatic and cardiac complications associated with high-fat/high-fructose diet in rats

The relationship between the incidence of cardiovascular abnormalities and non-alcoholic fatty liver disease (NAFLD) has long been postulated. Curcumin (CUR) is a potential anti-atherosclerotic agent but its poor water solubility hinders its pharmacological use. Therefore, the present study aimed to investigate the effect of formulation of CUR nanoemulsion prepared using the spontaneous emulsification technique on high fat high fructose (HFHF)-induced hepatic and cardiac complications. Fifty Wistar rats were divided into five groups. CUR nanoemulsion at doses of 5 and 10 mg/kg and conventional powdered CUR at a dose of 50 mg/kg were orally administered daily to rats for two weeks, and compared with normal control and HFHF control. Results revealed that the high dose level of CUR nanoemulsion was superior to conventional CUR in ameliorating the HFHF-induced insulin resistance status and hyperlipidemia, with beneficial impact on rats' recorded electrocardiogram (ECG), serum aspartate aminotransferase (ALT) and alanine aminotransferase (AST) levels, leptin, adiponectin, creatine phosphokinase, lactate dehydrogenase and cardiac troponin-I. In addition, hepatic and cardiac oxidative and nitrosative stresses, oxidative DNA damage and disrupted cellular energy statuses were counteracted. Results were also confirmed by histopathological examination. PRACTICAL APPLICATIONS: The use of curcumin nanoemulsion could be beneficial in combating hepatic and cardiac complications resulting from HFHF diets.

IGFBP-6: At the Crossroads of Immunity, Tissue Repair and Fibrosis

Insulin-like growth factors binding protein-6 (IGFBP-6) is involved in a relevant number of cellular activities and represents an important factor in the immune response, particularly in human dendritic cells (DCs). Over the past several years, significant insights into the IGF-independent effects of IGFBP-6 were discovered, such as the induction of chemotaxis, capacity to increase oxidative burst and neutrophils degranulation, ability to induce metabolic changes in DCs, and, more recently, the regulation of the Sonic Hedgehog (SHH) signaling pathway during fibrosis. IGFBP-6 has been implicated in different human diseases, and it plays a rather controversial role in the biology of tumors. Notably, well established relationships between immunity, stroma activity, and fibrosis are prognostic and predictive of response to cancer immunotherapy. This review aims at describing the current understanding of mechanisms that link IGFBP-6 and fibrosis development and at highlighting the multiple roles of IGFBP-6 to provide an insight into evolutionarily conserved mechanisms that can be relevant for inflammation, tumor immunity, and immunological diseases.

Screening and identification of potential protein biomarkers for the early diagnosis of acute myocardial infarction

Background

Acute myocardial infarction (AMI) is the most serious type of heart disease. Clinically, there is an urgent need to discover diagnostic biomarkers for the early diagnosis of AMI.

Methods

Serum proteomic profiles in AMI patients, healthy controls, and stable angina pectoris (SAP) patients were explored and compared by iTRAQ-2DLC-MS/MS. The clinical data of AMI patients were also analyzed. Differentially expressed proteins were validated by enzyme linked immunosorbent assay (ELISA), and diagnostic models were constructed.

Results

A total of 39 differentially expressed proteins were identified in AMI patients. The results showed that the serum levels of apolipoprotein E (APOE) in AMI patients were notably higher than those in the healthy controls (P=0.0172). The serum levels of aspartate aminotransferase (AATC) in AMI patients were markedly higher than those in the healthy controls and SAP patients (P<0.0001 and P<0.0001, respectively). The serum levels of fibronectin (FINC) in SAP patients were significantly higher than those in the healthy controls and AMI patients (P=0.0043 and P=0.0044, respectively). Clinical data analysis showed a considerable difference in blood glucose levels, troponin I (TNI), and creatine kinase (CK) in AMI patients compared with SAP patients and healthy controls. A diagnostic model consisting of AATC and clinical indicators [lactate dehydrogenase (LDH) and CK] was established to distinguish between AMI patients and healthy controls, with an area under the curve (AUC) value of 0.993 sensitivity and specificity of 96.2% and 96.3%, respectively. A diagnostic model consisting of AATC and CK was established to distinguish between AMI patients and SAP patients, with an AUC value of 0.975 and a sensitivity and specificity of 85.2% and 79.30%, respectively.

Conclusions

In this study, differentially expressed proteins in AMI patients were combined with clinical indexes, LDH and CK, and two diagnostic models were constructed. This study may provide meaningful data for the early diagnosis of AMI.

Identification and analysis of key genes associated with acute myocardial infarction by integrated bioinformatics methods

BACKGROUND

Acute myocardial infarction (AMI) is a common disease leading threat to human health around the world. Here we aimed to explore new biomarkers and potential therapeutic targets in AMI through adopting integrated bioinformatics tools.

METHODS

The gene expression Omnibus (GEO) database was used to obtain genes data of AMI and no-AMI whole blood. Furthermore, differentially expressed genes (DEGs) were screened using the "Limma" package in R 3.6.1 software. Functional and pathway enrichment analyses of DEGs were performed via "Bioconductor" and "GOplot" package in R 3.6.1 software. In order to screen hub DEGs, the STRING version 11.0 database, Cytoscape and molecular complex detection (MCODE) were applied. Correlation among the hub DEGs was evaluated using Pearson's correlation analysis.

RESULTS

By performing DEGs analysis, 289 upregulated and 62 downregulated DEGs were successfully identified from GSE66360, respectively. And they were mainly enriched in the terms of neutrophil activation, immune response, cytokine, nuclear factor kappa-B (NF-κB) signaling pathway, IL-17 signaling pathway, and tumor necrosis factor (TNF) signaling pathway. Based on the data of protein-protein interaction (PPI), the top 10 hub genes were ranked, including interleukin-8 (CXCL8), TNF, N-formyl peptide receptor 2 (FPR2), growth-regulated alpha protein (CXCL1), transcription factor AP-1 (JUN), interleukin-1 beta (IL1B), platelet basic protein (PPBP), matrix metalloproteinase-9 (MMP9), toll-like receptor 2 (TLR2), and high affinity immunoglobulin epsilon receptor subunit gamma (FCER1G). What's more, the results of correlation analysis demonstrated that there was positive correlation between the 10 hub DEGs.

CONCLUSION

Ten DEGs were identified as potential candidate diagnostic biomarkers for patients with AMI in present study. However, further experiments are needed to confirm the functional pathways and hub genes associated with AMI.

Diagnostic and Prognostic Biomarkers for Myocardial Infarction

The incidence of myocardial infarction (MI) increases every year worldwide. Better diagnostic and prognostic biomarkers for clinical applications are the consistent pursuit of MI research. In addition to electrocardiogram, echocardiography, coronary angiography, etc., circulating biomarkers are essential for the diagnosis, prognosis, and treatment effect monitoring of MI patients. In this review, we assessed both strength and weakness of MI circulating biomarkers including: (1) originated from damaged myocardial tissues including current golden standard cardiac troponin, (2) released from non-myocardial tissues due to MI-induced systems reactions, and (3) preexisted in blood circulation before the occurrence of MI event. We also summarized newly reported MI biomarkers. We proposed that the biomarkers preexisting in blood circulation before MI incidents should be emphasized in research and development for MI prevention in near future.

Circulating miR-130 is a potential bio signature for early prognosis of acute myocardial infarction

Background

As distinctive leading reasons of death globally, acute myocardial infarction (AMI). Accounts for major death ratio, caused by coronary artery disease (CAD). Its diagnosis relies on the presenting clinical symptoms, electrocardiograms (ECGs), and levels of circulating biomarkers. Recent studies have implicated microRNAs (miRNAs) in the pathogenesis of many diseases, including AMI. The present study inquire into feature value of miR-130 in AMI patients.

Methods

levels of expression of miR-130 in patient plasma, considered through simultaneous quantitative polymerase chain reaction (qRT-PCR). The method used for determining Plasma cardiac troponin I (cTnI) & creatine kinase-MB(CK-MB) degree set on by enzyme-linked immunosorbent assay (ELISA). The diagnostic value of miR-130 was measured using a receiver operating characteristic (ROC) curve.

Results

Plasma miR-130, cTnI, and CK-MB levels exist remarkably inflated in the AMI classification in comparison with control category (P<0.05). MiR-130 expression peaked 6 hours after disease onset, earlier than cTnI and CK-MB. The level of expression of miR-130 6 hours after disease onset was positively correlated with cTnI and CK-MB levels 12 hours after onset. The optimal cut-off point for miR-130 in peripheral blood, sensitivity, and specificity were 1.58 ng/mL, 82.5% and 77.5%, respectively. The area under curve (AUC) was 0.922.

Conclusions

These results indicate that circulating miR-130 holds great promise as an effective biomarker for diagnosing AMI earlier.

New Approaches to Identify Sepsis Biomarkers: The Importance of Model and Sample Source for Mass Spectrometry

Septic shock is a systemic inflammatory response syndrome associated with circulatory failure leading to organ failure with a 40% mortality rate. Early diagnosis and prognosis of septic shock are necessary for specific and timely treatment. However, no predictive biomarker is available. In recent years, improvements in proteomics-based mass spectrometry have improved the detection of such biomarkers. This approach can be performed on different samples such as tissue or biological fluids. Working directly from human samples is complicated owing to interindividual variability. Indeed, patients are admitted at different stages of disease development and with signs of varying severity from one patient to another. All of these elements interfere with the identification of early, sensitive, and specific septic shock biomarkers. For these reasons, animal models of sepsis, although imperfect, are used to control the kinetics of the development of the pathology and to standardise experimentation, facilitating the identification of potential biomarkers. These elements underline the importance of the choice of animal model used and the sample to be studied during preclinical studies. The aim of this review is to discuss the relevance of different approaches to enable the identification of biomarkers that could indirectly be relevant to the clinical setting.

Role of Adiponectin Gene and Receptor Polymorphisms and Their mRNA Levels with Serum Adiponectin Level in Myocardial Infarction

Background and Aim

Genetic factors are vital participants in the development and progression of myocardial infarction (MI). Adiponectin has been assumed to have a protective role in MI and adiponectin receptors variants could be a determinant for atherosclerosis. We aimed to evaluate the prevalence of ADIPOQ (rs2241766) and ADIPOR2 (rs10773989) polymorphisms and their association with mRNA levels and circulatory adiponectin levels in patients with MI.

Subjects and Methods

A total of 220 participants were classified into two groups: group 1 included 120 patients with MI, and group 2 involved 100 healthy participants as controls. Genotyping of ADIPOQ (rs2241766) and ADIPOR2 (rs10773989) polymorphisms were analyzed using an allele discrimination assay with real-time PCR and their relative expression or mRNA levels were determined by real-time PCR. Serum adiponectin level was determined using an ELISA technique.

Results

The ADIPOQ rs2241766 GG genotype and G allele and the CC genotype and C allele of ADIPOR2 rs10773989 were significantly prevalent in patients with MI and associated with increased risk of MI. We detected a marked reduction in serum adiponectin, ADIPOQ and ADIPOR2 mRNA levels in patients than control. The GG genotype of ADIPOQ rs2241766 and the CC genotype of ADIPOR2 rs10773989 had the lowest levels of their mRNA and adiponectin level in both patients and controls.

Conclusion

Adiponectin gene and receptor variants are potentially related to MI risk; furthermore, their expressions were markedly depressed in MI which suggests their use as potential biomarkers for MI.

Characterization of differentially expressed plasma proteins in patients with acute myocardial infarction

Acute myocardial infarction (AMI) remains a leading cause of morbidity and mortality worldwide. Novel biomarkers are needed to identify NSTEMI in AMI patients. The study objective was to use proteomics to identify novel plasma biomarkers for STEMI and NSTEMI patients. iTRAQ analysis was performed on pooled samples from 8 healthy controls and 12 STEMI and 12 NSTEMI patients. Bioinformatics analysis identified 95 differentially expressed proteins that were differentially expressed in the plasma of AMI patients and healthy controls; 28 of these proteins were found in STEMI/Con (22 upregulated and 6 downregulated), 48 in NSTEMI/Con (12 upregulated and 36 downregulated), and 44 in NSTEMI/STEMI (11 upregulated and 33 downregulated). Protein network analysis was then performed using STRING software. Functional analysis revealed that the identified plasma proteins were mainly involved with carbon metabolism, toll-like receptor signaling pathway, and hypertrophic cardiomyopathy. Nine of the proteins (SSA1, MDH1, FCN2, GPI, S100A8, LBP, vinculin, VDBP, and RBP4) that changed levels during AMI progression were further validated by ELISA. The constructed plasma proteome could reflect the AMI pathogenesis molecular mechanisms and provide a method for the early identification of NSTEMI in AMI patients. SIGNIFICANCE: The aim of this study was to use proteomics to identify novel predictive plasma biomarkers for patients with acute myocardial infarction (AMI), which would allow for either identification of individuals at risk of an infarction, and early identification of NSTEMI in patients with AMI. Using an approach that combined iTRAQ with LC-MS/MS, we found 95 proteins that showed significant differences in expression levels among the AMI patients and healthy controls. The proteins SSA1, MDH1, FCN2, GPI, S100A8, LBP, vinculin, VDBP, and RBP4 were found to play crucial roles in the pathogenesis of AMI. Using bioinformatics analysis, we found that dysregulation of carbon metabolism, toll-like receptor signaling pathway, and hypertrophic cardiomyopathy may be the major driving forces for cardiac damage during myocardial infarction. However, further investigations are needed to verify the mechanisms involved in the development of AMI especially NSTEMI. Taken together, our findings lay the foundation for understanding the molecular mechanisms underlying the pathogenic processes of AMI, and suggest potential applications for specific biomarkers in early diagnosis and determination of prognosis.

Quantitative Analysis of the Seminal Plasma Proteome in Secondary Hypogonadism

In the grey zone of testosterone levels between 8 and 12 nmol/L, the usefulness of therapy is controversial; as such, markers of tissue action of androgens may be helpful in adjusting clinical decisions. To better understand the effect of the hypothalamic-pituitary-testicular axis on male accessory secretion, we performed a proteomic quantitative analysis of seminal plasma in patients with secondary hypogonadism, before and after testosterone replacement therapy (TRT). Ten male patients with postsurgical hypogonadotrophic hypogonadism were enrolled in this study, and five of these patients were evaluated after testosterone treatment. Ten men with proven fertility were selected as a control group. An aliquot of seminal plasma from each individual was subjected to an in-solution digestion protocol and analyzed using an Ultimate 3000 RSLC-nano HPLC apparatus coupled to a LTQ Orbitrap Elite mass spectrometer. The label-free quantitative analysis was performed via Precursor Ions Area Detector Node. Eleven proteins were identified as decreased in hypogonadic patients versus controls, which are primarily included in hydrolase activity and protein binding activity. The comparison of the proteome before and after TRT comes about within the discovery of six increased proteins. This is the primary application of quantitative proteomics pointed to uncover a cluster of proteins reflecting an impairment not only of spermatogenesis but of the epididymal and prostate epithelial cell secretory function in male hypogonadism. The identified proteins might represent putative clinical markers valuable within the follow-up of patients with distinctive grades of male hypogonadism.