Biomarker For Myocardial Infarction Research Articles

STUDY OF PANEL OF DIAGNOSTIC CARDIAC MARKERS FOR ACUTE MYOCARDIAL INFARCTION

Objectives: The aim of this study is to estimate the level of creatine kinase-myocardial band (CK-MB), C-reactive protein (CRP), and lactate dehydrogenase (LDH) biomarker in myocardial infarction (MI) (troponin T-positive) and compare with normal healthy individuals (Troponin-T [TnT] negative).
 Methods: A cross-sectional study on 172 patients involving 100 patients with nondiabetic MI and 72 apparently healthy controls with no history of diabetes and/or MI was done from December 2017 to May 2018. The diagnosis of MI was established with electrocardiogram findings and TnT estimation. Blood samples were gathered and processed for the estimation of CK-MB, LDH, and CRP.
 Results: The mean age of the cases was 62.15±7.75 years and in the controls was 61.49±8.35 years (p=0.592). The mean value of CK-MB, LDH, and CRP in the TnT positive group was 111.94±29.59 IU/L, 564.43±110.99 IU/L, and 15.69±4.04 mg/L, whereas in the TnT negative group was 16.36±3.77 IU/L, 223.68±36.23 IU/L, and 6.08±2.02 mg/L, respectively (p<0.0001). CK-MB was deranged in 100% of TnT positive group, and in only 2.78% in TnT negative group (p<0.0001). LDH was deranged in 100% TnT positive group, and in 16.67% in TnT negative group (p<0.0001). CRP was deranged in 4% TnT positive group, and in 0% in TnT negative group (p=0.141).
 Conclusion: This study indicated that CK-MB and LDH are sensitive cardiac markers for the diagnosis of MI.

Simultaneous colorimetric determination of acute myocardial infarction biomarkers by integrating self-assembled 3D gold nanovesicles into a multiple immunosorbent assay.

An improved enzyme-free immunosorbent assay is described for the simultaneous detection of the myocardial infarction biomarkers N-terminal pro B type natriuretic peptide (NT-proBNP), creatine kinase-MB (CK-MB), and cardiac muscle troponin T (cTnT). The assay integrates 3D gold nanovesicles (GNVs) and three allochroic agents (phenolphthalein,methyl red,bromothymol blue). The pH regulated allochroic agents were enwrapped in GNVs to acts as ultrasensitive nanoprobes. Loading can be controlled by adjusting the temperature to efficiently load and release the allochroic agents. This bare-eye multicolor assay has limits of detection of 70pg·mL-1 for NT-proBNP, 910pg·mL-1 for CK-MB, and 7.8pg·mL-1 for cTnT. Other features include (a) a linear range that extends over a wide range and sometimes is better than conventional HRP-based immunoassays, and (b) a precision that is comparable to immunofluorescence assays as used in the clinical laboratory. Graphical abstract Schematic presentation of an improved enzyme-free immunosorbent assay (EFISA). It integrates 3D gold nano-vesicles (GNVs) and allochroic agents for the simultaneous detection of acute myocardial infarction (AMI) biomarkers (N-terminal prohormone of brain natriuretic peptide (NT-proBNP), kinase-muscle/brain test (CK-MB), and cardiac muscle troponin (cTnT)).

Role of high-sensitivity troponin T as a sensitive biomarker for postoperative myocardial infarction and outcome after isolated coronary artery bypass grafting surgery

Background Uncertainty exists about the diagnosis of post-coronary artery bypass grafting (CABG) Perioperative myocardial infarction (PMI) owing to nonconsensus for elevated biomarkers diagnostic levels and associated criteria. Post-CABG studies concerning high-sensitivity troponin (hs-TnT) and its role in the diagnosis of postoperative MI are few. Aim We are aiming to figure out the diagnostic and prognostic role of hs-TnT in individuals undergoing isolated coronary artery bypass graft surgery and whether it has relations to other diagnostic criteria. Patients and methods A total of 50 patients with multivessel coronary artery disease who elected for isolated CABG were enrolled in the study. Our exclusion criteria included individuals with chronic renal impairment, sepsis, and pre-existing high level of hs-TnT (unless >50% increment significantly raises its postoperative difference). Moreover, patients who experienced marked intraoperative hypotension (mean arterial blood pressure 5 min) were excluded. Levels of 140 ng/l (10 times 99th percentile upper reference limit) and 500 ng/l (10 times coefficient of variation of 10% for fourth-generation troponin T applied to hs-TnT) were predetermined. Results We enrolled 50 patients who underwent elective CABG. Their mean age was 59.8 ± 6.5 years, and there were 30 (60%) males. hs-TnT level was significantly associated with a higher incidence of off-pump CABG, higher cardiopulmonary bypass time, and higher aortic cross-clamp time. The composite morbidity was significantly higher in patients with hs-TnT level more than 500 (P Conclusion The occurrence of post-CABG MI is associated with a higher level of hs-TnT as well as a higher incidence of morbidity and mortality. The use of hs-TnT to diagnose post-CABG MI with a cut point of 10 times 99th percentile upper reference limit especially if associated with ECG and/or echocardiographic criteria predicts 30-day mortality.

Smartphone-app based point-of-care testing for myocardial infarction biomarker cTnI using an autonomous capillary microfluidic chip with self-aligned on-chip focusing (SOF) lenses.

Cardiovascular disease is one of the most common causes of mortality in the world. Most of the diagnostic processes usually require bulky instruments and trained professionals, which cannot meet the demand for fast, early and regular bedside diagnosis. In this paper, a bespoke app on a smartphone and an autonomous capillary microfluidic chip (ACMC) are combined to realize the point-of-care testing of cardiac troponin I (cTnI). The smartphone-app-ACMC platform was based on the sandwich immunofluorescence principle and featured self-aligned on-chip focusing (SOF) lenses which can avoid the complex optical coupling process. The operator only needs to introduce 100 μl sample into the ACMC, where the priming, time-delaying, mixing and washing steps for the assay can be accomplished automatically. With the help of the bespoke app and a palm-sized optical attachment, the smartphone can capture fluorescence images, process fluorescence intensity information, output detection results and save the results for long-term monitoring. Our results showed that within 12 min, the detection limit of 78 pg ml-1 and 94 pg ml-1 for cTnI was attained in buffer and spiked human serum, respectively. Our proposed platform has the potential to be applied in the POCT field especially for some resource-limited settings.

A Cardiac Troponin T Biosensor Based on Aptamer Self-assembling on Gold.

In this study, a sensitive and accurate aptasensor was designed for early detection of myocardial infarction through the determination of troponin T (TnT). The successful immobilization of a specific aptamer sequence on the surface of gold that had a high affinity toward TnT was accomplished. TnT was electrochemically quantified. The results indicated that the aptasensor detected TnT in a range of 0.05-5 ng mL, and with a detection limit of 0.01 ng/mL. The performance of the aptasensor was investigated by analyzing 99 human serum samples. Both diagnostic specificity and sensitivity of the aptasensor were found to be 95%. The use of the designed aptamer-based biosensor could be an essential achievement in health policy, preventing deaths caused by myocardial infarction, and reducing patients with heart failure. The extensive use of this aptamer-based biosensor can also reduce costs, enhance speed, and improve accuracy in the diagnosis of TnT as an important myocardial infarction biomarker.

MiRNA-1, miRNA-145 as a Myocardial Infarction Diagnostic Biomarker

Many myocardial infarction biomarkers currently available but they are a lack of specificity, therefore present study suggests to evaluate the significant importance of miRNA-1, miRNA-145 as biomarkers for early diagnosis of myocardial infarction. A blood sample was collected from three groups. The first group was patients with acute myocardial infarction (MI), the Second group was patients who have a risk factor for MI, and the Third group included healthy volunteers. Serum blood of this sample used to RNA purification and cDNA application with stem-loop specific primer then miRNA-1, and miRNA-145 was quantitated by using RT-PCR. The level of miR-1 fold change was significantly highest in the MI group followed by risk group and then by control group (P<0.05). while of miRNA-145 fold change was significantly lowest in the MI group followed by risk group and then by control group (P<0.05). A receiver operator characteristic (ROC) analysis; the cut off value was identified at miRNA-1 of >5.28 fold change with a sensitivity of 91.67 % and a specificity of 90.7%, while the cut off value of miRNA-145 has cut off ≤ 0.7 fold change with a sensitivity of 95.83 % and a specificity of 89.47%. miRNA-1, miR145 has high sensitivity and Specificity in this study which was bushed to using them as an alone biomarker or supported for Another biomarker in AMI diagnosis.

Nanomaterials‐based Electrochemical Sensing of Cardiac Biomarkers for Acute Myocardial Infarction: Recent Progress

AbstractThe development of the methods for early and accurate diagnosis of acute myocardial infarction are needed to facilitate immediate treatment of patients. One of the ways to achieve that is the detection of cardiac biomarkers for myocardial infarction, such as thrombin, cardiac troponins (I and T), myoglobin, etc. Nanotechnology has played an important role in the development of sensitive and efficient electrochemical sensors for cardiac biomarkers. In this review, we discuss recent progress on nanomaterial‐based electrochemical sensing of various cardiac biomarkers for acute myocardial infarction.

Screening and Identification of Pregnancy Zone Protein and Leucine-Rich Alpha-2-Glycoprotein as Potential Serum Biomarkers for Early-Onset Myocardial Infarction using Protein Profile Analysis.

The present study aims to discover novel serum biomarkers of early-onset myocardial infarction (MI) using proteomic analysis. In the first stage, the iTRAQ-coupled LC-MS/MS technique is utilized to investigate protein profiles of patients with early-onset MI. In the second stage, these candidate proteins are validated using ELISA. A total of 538 proteins are quantified, with pregnancy zone protein (PZP), leucine-rich α-2-glycoprotein (LRG) and Apolipoprotein C-I (Apo C-I) being upregulated and Apolipoprotein A-I (Apo A-I) and Apolipoprotein A-IV (Apo A-IV) downregulated in early-onset MI patients. Results from the validation stage demonstrate that the serum concentrations of PZP and LRG are significantly increased in the early-onset MI group. The correlation between the concentrations of C-reactive protein (CRP) and the two candidate biomarkers is positive. Area under the curve values used to diagnose early-onset MI for LRG and PZP are 0.939 and 0.874, respectively. Five differential serum proteins are identified in early-onset MI using proteomic analysis. Lipoprotein-related biomarkers further demonstrate the close relationship between lipid metabolism and the disease. Inflammation-associated LRG and PZP may be novel biomarkers of the disease. In addition, changes in these proteins may partly reveal the possible mechanisms in the pathogenesis and pathophysiology of early-onset MI.

Characterisation of a myocardial infarction biomarker, brain-type natriuretic peptide, as a biomarker of cognitive dysfunction

Characterisation of a myocardial infarction biomarker, brain-type natriuretic peptide, as a biomarker of cognitive dysfunction

Troponin Structure and Function in Health and Disease

<h3>ABSTRACT</h3> Troponin (Tn) is a heterotrimeric protein containing 3 subunits (C, T, and I) with different molecular weights and distinctive functions. The subunits of Tn work cohesively to regulate the contraction and relaxation activities of striated muscles: troponin-C (TnC) binds calcium (Ca²⁺); troponin-T (TnT) interacts with tropomyosin (Tm) and anchors Tn to actin; and troponin-I (TnI) inhibits the adenosine triphosphatase (ATPase) activity of the actomyosin cross-bridge and effectively blocks the myosin-binding site on actin subunits. At a genetic level, there are 8 distinctive Tn genes (isoforms) that code for tissue-specific heart and skeletal muscle protein subunits: TNNI1, TNNI2, TNNI3, TNNT1, TNNT2, TNNT3, TNNC1, and TNNC2. The gene isoforms are regulated throughout development via posttranscriptional and posttranslational modifications. Genetic mutations in any of the 3 protein subunits could be linked to hypertrophic, dilated, and restrictive cardiomyopathies. Tn release by damaged cardiomyocytes is clinically used as a biomarker for myocardial infarction (MI), and its release into the serum is measured at specific times postinjury for diagnostic or prognostic purposes. Current tests that measure serum Tn are fifth generation assays, which have improved sensitivity and specificity compared with previous assays. However, increased serum Tn levels have been seen in chronic diseases such as Fabry disease and chronic renal disease. It is important to remember, when clinically examining a patient, that Tn levels are only one piece of the puzzle. A patient’s history or symptoms are essential for making an accurate diagnosis.

Abstract 460: Diabetes Impairs Reparative Property of Bone Marrow-derived Endothelial Progenitor Cells: Role of Mir-499-mediated Hydrogen Sulfide Deficiency

Background: miR-499 has been considered as a potential biomarker for myocardial infarction. Overexpression of miR-499 impaired heart function and induced cardiac hypertrophy in mice. Recent studies suggested miR-499 suppresses tumor growth through the inhibition of vascular endothelial growth factor (VEGF) mediated angiogenesis. Furthermore, emerging evidences indicate that miR-499 is increased in heart of diabetic rodents and patients. Here, we tested the hypotheses that miR-499 impairs angiogenic ability of endothelial cells (ECs) under diabetic conditions. Methods and Results: miR-499 levels were examined in endothelial progenitor cells (EPCs), microvascular endothelial cells (MVECs) and plasma in diabetic db/db mice (8-week, male). Gender- and age-matched non-diabetic db/+ mice served as controls. EPCs were isolated from bone marrow density-gradient centrifugation. MVECs were isolated using collagenase. We found that miR-499 levels were significantly increased in EPCs, MVECs as well as plasma of db/db mice. miR-499 antagomiR rescued high glucose (25 mM D-glucose for 48 h)-impaired tube formation and migration of human cardiac microvascular endothelial cells (HCMVECs). Mechanistically, by luciferase assay, we found that miR-499 directly targets cystathionine γ-lyase (CSE), a major hydrogen sulfide (H 2 S)-synthesizing enzyme in cardiovascular cells. Overexpression of miR-499 by transfection of miR-499 mimics decreased CSE protein levels and intracellular H 2 S production in HCMVECs. Conclusions: Our results suggest that miR-499-induced CSE downregulation/inactivation thus H 2 S reduction may play an important role in diabetes-impaired angiogenic capacity. Silencing miR-499 in diabetic EPCs/ECs may provide a novel tool for the treatment of ischemic tissue injury in patients with diabetes.

MiRNome analysis in search of potential myocardial infarction biomarker

miRNome analysis in search of potential myocardial infarction biomarker

Isolation and Quantification of Nanovesicles in Isoproterenol-Induced Myocardial Infarcted Rats

Introduction and Aim: Myocardial infarction (MI) is one of the leading causes of death worldwide. The pathogenesis and aetiology of MI is still unclear and there is currently no cure for MI. Cardiac troponin is the only well-known cardiac-specific marker for the diagnosis of MI but due to the delayed release of troponin in the circulation, a novel cardiac biomarker is needed in the early stages of development of MI to reduce MI mortality. Recently, it has been reported that exosome concentration is highly regulated by stress and cardiovascular diseases (CVDs). We assessed the hypothesis that exosome secretion by the injured cardiomyocytes is increased during MI and thereby serve as biomarker for MI. The aim of this study was to quantify exosomes in an isoproterenol (ISO)-induced MI rats. Method: Twelve rats were divided into two groups (group A and B). Group-A (n=6) was the normal control rats and group-B (n=6) was the ISO-treated group. Group-B animals were injected with isoproterenol (85mg/kg/bw) for two consecutive days to induce MI. Blood pressure (BP), heart rate (HR) and body weight were monitored for 7 days in all animals prior the ISO injection and throughout the experiment. After second ISO-injection, all animals were sacrificed and blood, heart tissues were obtained. Histopathological analysis was performed in heart tissue samples and levels of cardiac markers (creatine kinase-MB, lactate dehydrogenase and troponin T) were measured from the serum. Exosomes were isolated from the plasma by differential ultracentrifugation. Exosomes were quantified and characterized using nanoparticle tracking analysis (NTA), transmission electron microscope (TEM) study and ELISA for the quantification of circulating exosomal protein (CD63). Result and Discussion: ISO injection caused the development of MI and was confirmed by the increase in BP, Cardiac markers (cardiac troponin T, lactate dehydrogenase and creatine kinase). NTA together with TEM analysis revealed particle sizes of the exosome and showed an elevated number of the exosome in ISO-treated animals. Levels of exosomal protein (CD63) were also increased in ISO-treated animals. Conclusion: The concentration of exosomes was increased in MI rats indicating that circulating exosomes may be used as a novel diagnostic marker for MI.

Coreactant-Free and Label-Free Eletrochemiluminescence Immunosensor for Copeptin Based on Luminescent Immuno-Gold Nanoassemblies.

In this work, the eletrochemiluminescence (ECL) behavior of Cu2+/cysteine complexes and N-(aminobutyl)- N-(ethylisoluminol) (ABEI) functionalized gold nanoparticles combined with chitosan (Cu2+-Cys-ABEI-GNPs-CS) were studied by cyclic voltammetry and a double-step potential, which exhibited excellent ECL properties without any coreactant. It was found that the ECL intensity of Cu2+-Cys-ABEI-GNPs-CS could increase at least 1 order of magnitude compared with that of Cu2+-Cys-ABEI-GNPs. Furthermore, a coreactant-free and label-free ECL immunosensor has been established for the determination of early acute myocardial infarction biomarker copeptin based on luminescent immuno-gold nanoassemblys consisting of Cu2+-Cys-ABEI-GNPs-CS and immuno-gold nanoparticles prepared by connecting copeptin antibody with trisodium citrate stabilized gold nanoparticles. In the presence of copeptin, an obvious decrease in ECL intensity was observed due to the formation of antibody-antigen immunocomplex, which could be used for the determination of copeptin in the range of 2.0 × 10-14-1.0 × 10-11 mol/L with a detection limit of 5.18 × 10-15 mol/L. The detection limit of the ECL immunosensor is at least 2 orders of magnitude lower than that of sandwich immunoassays based on labeling technology. Also, the ECL immunosensor does not need any coreactant and avoids complicated labeling and purification procedure. It is ultrasensitive, simple, specific, and low-cost. This work reveals that the proposed luminescent immuno-gold nanoassemblies are ideal nanointerfaces for the construction of immunosensors. The proposed strategy may be used for the determination of other antigens if corresponding antibodies are available.

Comprehensive Characterization of Swine Cardiac Troponin T Proteoforms by Top-Down Mass Spectrometry.

Cardiac troponin T (cTnT) regulates the Ca2+-mediated interaction between myosin thick filaments and actin thin filaments during cardiac contraction and relaxation. cTnT is released into the blood following injury, and increased serum levels of the protein are used clinically as a biomarker for myocardial infarction. Moreover, mutations in cTnT are causative in a number of familial cardiomyopathies. With the increasing use of large animal (swine) model to recapitulate human diseases, it is essential to characterize species-dependent protein sequence variants, alternative RNA splicing, and post-translational modifications (PTMs), but challenges remain due to the incomplete database and lack of validation of the predicted splicing isoforms. Herein, we integrated top-down mass spectrometry (MS) with online liquid chromatography (LC) and immunoaffinity purification to comprehensively characterize miniature swine cTnT proteoforms, including those arising from alternative RNA splicing and PTMs. A total of seven alternative splicing isoforms of cTnT were identified by LC/MS from swine left ventricular tissue, with each isoform containing un-phosphorylated and mono-phosphorylated proteoforms. The phosphorylation site was localized to Ser1 for the mono-phosphorylated proteoforms of cTnT1, 3, 4, and 6 by online MS/MS combining collisionally activated dissociation (CAD) and electron transfer dissociation (ETD). Offline MS/MS on Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer with CAD and electron capture dissociation (ECD) was then utilized to achieve deep sequencing of mono-phosphorylated cTnT1 (35.2kDa) with a high sequence coverage of 87%. Taken together, this study demonstrated the unique advantage of top-down MS in the comprehensive characterization of protein alternative splicing isoforms together with PTMs. Graphical Abstract ᅟ.

High sensitive and multiple detection of acute myocardial infarction biomarkers based on a dual-readout immunochromatography test strip

Immunochromatography test strip (ICTS) displayed high advantages in screening acute myocardial infarction (AMI) biomarkers. However, the low sensitivity and nonquantitative results seriously limited its clinical application. Herein, we designed a highly sensitive, quantitative and dual-readout ICTS for assaying multiple AMI biomarkers based on magnetic nanoparticles (MNPs) quenching the fluorescence of Cy5, which was labeled on capture antibodies on test (T) lines. The changes of fluorescent intensity caused by MNPs nanoprobes enabled us to sensitively quantify cTnI and CK-MB for early diagnosis of AMI in 15 min with a corresponding detection limit of 0.049 ng/mL and 0.085 ng/mL, respectively. Meanwhile, the aggregations of MNPs on T lines allowed colorimetric readout in 2 min for rapid diagnosis of emergent and severe AMI patients. Furthermore, the detection results of 30 clinical serum samples were coincident with those by electrochemiluminescence immunoassay. So this approach is promising a new avenue for clinical diagnosis and prognosis of AMI.

Circulating miR-23b as a Novel Biomarker for Early Risk Stratification After ST-Elevation Myocardial Infarction.

BackgroundmiR-23b overexpression can promote cardiomyocyte apoptosis and reduce cell growth under hypoxic conditions, suggesting that miR-23b acts as a biomarker for ST-elevation myocardial infarction (STEMI). The aim of this study was to investigate the effect of miR-23b on STEMI patients.Material/MethodsWe enrolled 80 eligible patients with STEMI and 60 control subjects. Blood samples were obtained at 6 h, 12 h, 24 h, 48 h, 3 days, and 7 days after the onset of symptoms. Another blood sample was collected before and after percutaneous coronary intervention (PCI). The samples were used for real-time quantitative PCR analysis. A Siemens Immulite2000 detector (Germany) was used for cTnI detection, and the serum CK-MB content was detected by electrochemical luminescence method.ResultsThe expression level of miR-23b was increased in patients with STEMI (P<0.05). No significance difference was observed among risk factors, although the clinical data was comparable (P>0.05). The level of miR-23b in STEMI patients after PCI was lower (P<0.05). The ROC curve of plasma miR-23b showed a separation, with an AUC of 0.809 (95%CI, 0.737–0.936, P<0.05), compared to CK-MB with an AUC of 0.753 (95%CI, 0.707–0.896) and cTnI with an AUC of 0.783 (95%CI, 0.723–0.917).ConclusionsThe present study reveals that miR-23b is a useful biomarker of STEMI, providing a novel insight for the diagnosis for STEMI.

Characterization of dysregulated lncRNA-mRNA network based on ceRNA hypothesis to reveal the occurrence and recurrence of myocardial infarction

Accumulating evidence has demonstrated that long non-coding RNAs (lncRNAs) acting as competing endogenous RNAs (ceRNAs) play important roles in initiation and development of human diseases. However, the mechanism of ceRNA regulated by lncRNA in myocardial infarction (MI) remained unclear. In this study, we performed a multi-step computational method to construct dysregulated lncRNA-mRNA networks for MI occurrence (DLMN_MI_OC) and recurrence (DLMN_MI_Re) based on “ceRNA hypothesis”. We systematically integrated lncRNA and mRNA expression profiles and miRNA-target regulatory interactions. The constructed DLMN_MI_OC and DLMN_MI_Re both exhibited biological network characteristics, and functional analysis demonstrated that the networks were specific for MI. Additionally, we identified some lncRNA-mRNA ceRNA modules involved in MI occurrence and recurrence. Finally, two new panel biomarkers defined by four lncRNAs (RP1-239B22.5, AC135048.13, RP11-4O1.2, RP11-285F7.2) from DLMN_MI_OC and three lncRNAs (RP11-363E7.4, CTA-29F11.1, RP5-894A10.6) from DLMN_MI_Re with high classification performance were, respectively, identified in distinguishing controls from patients, and patients with recurrent events from those without recurrent events. This study will provide us new insight into ceRNA-mediated regulatory mechanisms involved in MI occurrence and recurrence, and facilitate the discovery of candidate diagnostic and prognosis biomarkers for MI.

Ultrasensitive label-free optical microfiber coupler biosensor for detection of cardiac troponin I based on interference turning point effect

Sensitive detection of cardiac biomarkers is critical for clinical diagnostics of myocardial infarction (MI) while such detection is quite challenging due to the ultra-low concentration of cardiac biomarkers. In this work, a label-free immunosensor based on optical microfiber coupler (OMC) has been developed for the ultrasensitive detection of cardiac troponin I (cTnI), a selective and highly sensitive biomarker of acute myocardial infarction (AMI). CTnI monoclonal antibodies were immobilized on the surface of the fiber through polyelectrolyte layer using layer-by-layer deposition technique. For refractive index sensing characterization, an ultra-high sensitivity of 91777.9 nm/RIU was achieved when the OMC works around the dispersion turning point, which is the highest experimental demonstration in the field of fiber-optic evanescent biosensors. For biosensing, the immunosensor with good specificity showed a linear wavelength shift in the range of 2–10 fg/mL and an ultra-low detection limit of 2 fg/mL. Such immunosensors have huge application potential for the detection of cardiac biomarkers of myocardial infarction due to simple detection scheme, quick response time, ease of handling and miniaturation.

MicroRNAs as predictive biomarkers for myocardial injury in aged mice following myocardial infarction.

The occurrence of myocardial infarction (MI) increases appreciably with age. In the Framingham Heart Study, the incidence of MI more than doubles for men and increases more than five-fold in women (ages 55-64 years compared to 85-94 years). MicroRNAs (miRNAs) quantitatively regulate their target's expression post-transcriptionally by either silencing action through binding at the 3'UTR domains or degrading the messages at their coding regions. In either case, these regulations affect the cardiac transcriptional output and cardiac function. Among the known cardiac associated miRNA, miRNA-1, miRNA-133a, and miRNA-34a have been shown to induce adverse structural remodeling to impair cardiac contractile function. In the present study, an in vivo model of MI in young (3 month) and old (22 month) mice is used to investigate the possible role whereby these three miRNAs exert negative effects on heart function following MI. Herein we demonstrate that in older mouse heart, all three microRNAs show increased levels of expression, while miRNA-1 shows a further increase in old mouse heart following MI, which corresponds to left ventricular (LV) wall thinning. These structural changes in cardiac tissue may causes downstream LV dilation and subsequent LV dysfunction. Results presented here suggest that significantly elevated levels of miRNA-1 in post-MI old heart could be predictive of cardiac injury in older mice as the high risk biomarker for MI in older individuals.