Laboratory diagnosis of acute myocardial injury

Levels of cardiac troponin-T and LDL-C to HDL-C ratio of hospitalized COVID-19 patients: A case-control study

Background: People with coronavirus disease 2019 (COVID-19) are frequently at higher risk of developing cardiovascular and metabolic disorders, which are strongly related to the development of long-term illness and higher mortality. These effects may be caused by several interrelated processes, including the IL-6 driven cytokine storm or uncontrolled angiotensin II stimulation. In addition, the direct viral infection of cardiac myocytes is thought to cause cardiac injury because it increases metabolic demand, activates the immune system, and causes vasculature disruption. The objective of this study was to determine whether there is a relationship between cardiac troponin-T (cTnT) and low-density lipoprotein cholesterol (LDL-C) to high-density lipoprotein cholesterol (HDL-C) ratio values with COVID-19. Methods: During the data collection stage, 90 participants were included, 45 healthy controls and 45 hospitalized patients diagnosed with COVID-19 using reverse transcription-quantitative PCR (RT-qPCR). Each participant provided 5 ml venous blood to begin analyzing cTnT and LDL-C:HDL-C ratio levels in their blood to see whether there is an association between the level of any of these markers and COVID-19 infection using SPSS version 23. Results: This research reported a significant rise in the measured values of cTnT and LDL-C:HDL-C ratio in patients' blood compared to controls, with P-values of 0.025 and 0.000, respectively, in which alpha values < 0.05, These biomarkers hold the promise in predicting COVID-19 severity, and early treatment may help reduce complications. Conclusions: Due to the fact that cTn is a diagnostic marker of disease activity and a strong independent predictor of negative events, its usage in emergency rooms may well be advantageous. If cTn is elevated, hospitalization may be indicated. A difference in the blood LDL-C:HDL-C ratio of COVID-19 patients demonstrated an association with the illness. Because lipid studies are inexpensive and reliable to do, they may aid clinicians in identifying the severity of COVID-19.

Biomarkers of Uremic Cardiotoxicity

Cardiovascular (CV) morbidity and mortality increase along with the progression of chronic kidney disease (CKD). The potential novel biomarkers of cardiotoxicity have been tested with the aim of the early detection of patients at high CV risk, and among them are markers of inflammation, oxidative stress, acute renal injury, and microRNAs. The study analyzed biomarkers in non-dialysis-dependent (NDD; stage 3a-4 CKD) and dialysis-dependent (DD) CKD patients. The prospective cohort study included 87 patients who were followed for 18 months, during which period newly occurred CV events were recorded. Cox regression analysis confirmed serum albumin, urea, interventricular septum thickness diameter (IVST), the use of calcium antagonist, and erythropoiesis-stimulating agent to be significant predictors of CV outcome. No significant difference was observed in biomarkers of inflammation, oxidative stress, acute kidney injury (IL-18, CRP, ferritin, IMA, SOD, NGAL, and KIM-1), and miR-133a, in regards to the presence/absence of CV event, CV death, and left ventricular hypertrophy. Serum albumin, urea, IVST, and the use of calcium antagonist and erythropoiesis-stimulating agents were confirmed to be factors associated with CV events in CKD patients. Apart from traditional risk factors, new research is needed to define novel and reliable biomarkers of cardiotoxicity in CKD patients.

Early markers for myocardial ischemia and sudden cardiac death

The post-mortem diagnosis of acute myocardial ischemia remains a challenge for both clinical and forensic pathologists. We performed an experimental study (ligation of left anterior descending coronary artery in rats) in order to identify early markers of myocardial ischemia, to further apply to forensic and clinical pathology in cases of sudden cardiac death. Using immunohistochemistry, Western blots, and gene expression analyses, we investigated a number of markers, selected among those which are currently used in emergency departments to diagnose myocardial infarction and those which are under investigation in basic research and autopsy pathology studies on cardiovascular diseases. The study was performed on 44 adult male Lewis rats, assigned to three experimental groups: control, sham-operated, and operated. The durations of ischemia ranged between 5 min and 24 h. The investigated markers were troponins I and T, myoglobin, fibronectin, C5b-9, connexin 43 (dephosphorylated), JunB, cytochrome c, and TUNEL staining. The earliest expressions (≤30 min) were observed for connexin 43, JunB, and cytochrome c, followed by fibronectin (≤1 h), myoglobin (≤1 h), troponins I and T (≤1 h), TUNEL (≤1 h), and C5b-9 (≤2 h). By this investigation, we identified a panel of true early markers of myocardial ischemia and delineated their temporal evolution in expression by employing new technologies for gene expression analysis, in addition to traditional and routine methods (such as histology and immunohistochemistry). Moreover, for the first time in the autopsy pathology field, we identified, by immunohistochemistry, two very early markers of myocardial ischemia: dephosphorylated connexin 43 and JunB.

Evaluation of the anti-myocardial ischemia effect of individual and combined extracts of Panax notoginseng and Carthamus tinctorius in rats

ETHNOPHARMACOLOGICAL RELEVANCE

The decoction of combined Panax notoginseng (Burk) F.H. Chen and Carthamus tinctorius L. has a history of use in traditional medicine for the prevention and treatment of cardiovascular diseases such as angina pectoris and myocardial infarction.

AIM OF THE STUDY

In this study, we investigated the effects of individual herbal extracts and combined extracts on anti-myocardial ischemia injuries in vivo, and determined the proper dosage of Panax notoginseng (EPN) combined with Carthamus tinctorius (ECT) that could strengthen their cardio-protective effects. Meanwhile, their potential anti-oxidative stress and anti-inflammation effect were assessed.

MATERIAL AND METHODS

SD rats were orally given individual EPN 50, 100mg/kg, ECT 100, 200mg/kg, and different combinations between them. Myocardial infarction was produced by occlusion of the left anterior descending coronary artery for 24h. Infarct area was determined with 2,3,5-triphenyltetrazolium chloride (TTC) staining. The biomarkers related to myocardial ischemia injury were determined. Simultaneously, hemodynamic parameters were monitored as left ventricular systolic pressure (LVSP), LV end-diastolic pressure (LVEDP) and maximal rate of increase and decrease of left ventricular pressure (dP/dt(max)). The oxidative stress indicators and inflammatory factors were also evaluated.

RESULTS

The results showed EPN or ECT significantly reduced infarct size, improved cardiac function, decreased levels of creatine kinase (CK) and lactate dehydrogenase (LDH) (all P<0.05 vs. control ). EPN or ECT alone also restrained the oxidative stress related to myocardial ischemia injury as evidenced by decreased malondialdehyde (MDA) and elevated superoxide dismutase (SOD) activity (all P<0.05 vs. control). However, this cardio-protective effect was further strengthened by their combinations. Among all the combinations, EPN 50mg/kg plus ECT 200mg/kg showed predominant potential to reduce infarct size (22.21±1.72%, P<0.05 vs. each single, respectively), preserve cardiac function (P<0.05 vs. ECT 200mg/kg for LVEDP and -dP/dt(max)) after myocardial ischemia injury in rats. This heart protection was confirmed with the lowered cardiac troponin I (cTnI) (P<0.05 vs. ECT 200mg/kg and EPN 50mg/kg, respectively). Oxidative stress and inflammation are the two key factors in the pathogenesis of myocardial ischemia injury. In the present study, EPN 50mg/kg plus ECT 200mg/kg markedly increased SOD and GSH-Px activity (475.30±23.60U/ml, P<0.05 vs. each single, respectively), while elevated MDA level was significantly depressed. Meanwhile, the inflammatory cascade was inhibited as evidenced by decreased cytokines such as tumor necrosis factor-α (TNF-α), C-reactive protein (CRP) and interleukin-1β (IL-1β).

CONCLUSION

These results demonstrated EPN, ECT and their combinations exhibited significant cardio-protective effects. The findings suggest EPN combined with ECT may be therapeutically more useful for ameliorating anti-myocardial ischemia injuries than individual herbal extract, and EPN 50mg/kg plus ECT 200mg/kg is the appropriate combination in the present research. The cardio-protective effect of this combination was achieved partially by decreasing oxidative stress and repressing inflammatory cascade.

Increased plasma cardiac troponin I concentration in lambs with myocarditis

BACKGROUND

Cardiac troponin I (cTnI) is a blood biomarker of myocardial injury. A human cTnI assay may be useful for measuring cTnI concentrations in lambs with naturally occurring myocarditis.

OBJECTIVE

The aims of this study were to evaluate the utility of a commercially available human chemiluminescent microparticle cTnI immunoassay for measuring plasma cTnI concentrations in lambs with naturally occurring myocarditis from infection with foot and mouth disease virus (FMDV), and to determine cTnI expression in cardiac muscle of affected lambs.

METHODS

Ten lambs with myocarditis and 10 clinically healthy lambs (control group) were included. Clinical signs, gross and histologic necropsy findings, and immunoreactivity for cTnI in cardiac tissue were evaluated. Plasma cTnI concentration was determined using the commercial human immunoassay system.

RESULTS

All lambs with myocarditis died within 1 day of clinical signs. Infection with FMDV was confirmed by PCR analysis. Gross cardiac lesions were evident and histologic examination revealed myocarditis. Immunoreactivity for cTnI was absent in cardiac myocytes that were degenerative or necrotic, but was strong in cardiac myocytes from unaffected areas of the myocardium and in all cardiac myocytes of healthy lambs. The geometric mean plasma concentrations of cTnI for lambs in the myocarditis and control groups were 146.78 μg/L (95% confidence interval [CI], 61.90-348.06) and 0.013 μg/L (95% CI, 0.010-0.017), respectively (t-value 19.27; P < .0001).

CONCLUSIONS

A commercial human cTnI assay may be used to detect plasma cTnI concentrations in sheep, and cTnI may be used as a blood-based biomarker of myocarditis in this species.

The saponin of red ginseng protects the cardiac myocytes against ischemic injury in vitro and in vivo

Steamed root of Panax ginseng C.A. Mayer, known as "red ginseng", differs from other ginseng preparations in terms of its saponin components and content, as some partly deglycosylated saponins are produced as artifacts during the steaming process. However, whether saponins derived from red ginseng (SRG) can have a protective effect on cardiomyocytes remains unknown. The present study aimed to explore the effect of SRG on myocardial ischemia in vitro and in vivo. MTT assays revealed that SRG pretreatment significantly increased the viability of cardiomyocytes injured by Na(2)S(2)O(4) hypoxia in vitro. This effect was almost completely abolished by glibenclamide, a blocker of the ATP-sensitive potassium channel, but the cardioprotective activity of SRG was not influenced by the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. SRG also significantly reduced the Na(2)S(2)O(4)-induced increase in intracellular calcium, as shown by Fluo-3/AM probes with flow cytometry. Adult rat heart ischemia, which was induced by ligation of the left anterior descending coronary artery, was employed for the in vivo analysis. SRG pretreatment reduced infarct size and resulted in a higher left ventricle (LV) developed pressure, LV (+)dP/dt(max) and LV systolic pressure and lower LV (-)dP/dt(max) and LV end diastolic pressure after 24h of ischemia. Moreover, SRG significantly reduced the level of cardiac Troponin I (cTnI) in the serum, which suggests that cTnI, a protein component of the troponin regulatory complex involved in cardiac contractility, contributes to the SRG-mediated recovery of cardiac systolic function. In conclusion, this study is the first to provide evidence and a mechanistic analysis of the cardioprotective effects of SRG. SRG significantly attenuated myocardial ischemic injury by improving cardiac systole function, partly by reducing cTnI secretion and improving cardiac diastolic function. Also, SRG attenuated the Ca(2+) overload in cardiomyocytes and modulated the K(ATP), but not PI3K, signaling pathway; taken together, these mechanisms synergistically reduced infarct size.

Combinatorial Determination of Ischemia Modified Albumin and Protein Carbonyl in the Diagnosis of NonST-Elevation Myocardial Infarction

Ischemia modified albumin (IMA) and Protein Carbonyl (PC) have known as proteins that are modified on the similar basis of oxidative stress induced protein modification and may have diagnostic potential in acute myocardial infarction. This study aims to evaluate the ability of using IMA and PC content to diagnose Non-ST elevation myocardial infarction (NSTEMI) and efficiency of combining these two markers. Serum from NSTEMI and healthy control were determined for serum IMA and PC content. The results showed that both of serum IMA level and PC content in NSTEMI was significantly higher than that of healthy controls. However, the PC content showed greater diagnostic performance than IMA. Combinatorial determination of serum IMA level with PC content level was enhanced test efficiency. In conclusion, our finding demonstrated that IMA and PC content can be used as a diagnostic marker for NSTEMI.

Electrochemical nanobiosensor for express diagnosis of acute myocardial infarction in undiluted plasma

The myocardial infarction biomarker myoglobin was quantified at the biological level in undiluted plasma using developed electrochemical nanosensors with immobilized anti-myoglobin. Method for cardiac myoglobin detection is based on direct electron transfer between Fe(III)-heme and electrode surface modified with gold nanoparticles/didodecyldimethylammonium bromide (DDAB/Au) and antibodies. The procedure of myoglobin detection was optimized (pH, incubation times and characteristics of electrodes) to express determination of the marker in serum or plasma. Plasma of healthy donors and patients with acute myocardial infarction (AMI) was analyzed using electrochemical immunosensors and RAMP immunoassay. Square wave voltammetry cathodic peak of cardiac myoglobin reduction was found to be proportional to myoglobin quantity in plasma as determined by RAMP. The method proposed does not require signal enhancement or amplification; nor does it require labeled secondary antibodies. Immunosensor has a detection limit of 10 ng/ml (0.56 nM) and a broad range of working concentrations (10-1780 ng/ml; 0.56-100 nM). The whole procedure takes 30 min and can be used for express diagnosis of acute myocardial infarction.

Evaluation of postmortem measurement of NT-proBNP as a marker for cardiac function

Clinical biomarkers of cardiac function could also be monitored postmortem. Among the natriuretic peptides, the aminoterminal portion of pro-brain natriuretic peptide (NT-proBNP) appears to be a more reliable postmortem tool than the BNP, owing to its longer half-life and greater stability. In living persons, NT-proBNP is considered to be a marker of heart failure, and its level rises after cardiac ischemia. The goal of this study was first to evaluate the postmortem stability of NT-proBNP, then to measure the NT-proBNP levels in postmortem cases of heart failure related to coronary ischemia. The goal of this study was also to evaluate the correlations between different specimens collected at autopsy (e.g. blood, serum, vitreous humor and pericardial fluid). The study included 96 cases, which were classified into 4 groups according to the autopsy and histological findings. The NT-proBNP levels were significantly higher in individuals who had suffered from chronic cardiac ischemia, with or without acute coronary events, than in either control cases or those who had suffered from acute thromboembolism or acute rupture of a plaque without chronic cardiac ischemia. The highest levels were registered in individuals who had suffered from acute coronary thromboembolism in association with chronic coronary ischemia. Good correlations in the NT-proBNP levels for the different specimens were observed between samples of femoral blood, serum, and pericardial fluid. Our data indicated that postmortem measurements of NT-proBNP are reliable and compatible with clinical findings.

Mechanisms underlying B-cell tolerance induction by antigen-immunoglobulin G gene transfer

Previous studies on the mechanisms underlying tolerance induction in diabetes have mainly focused on T cells, however B cells also have an important role in diabetes. Based on our previous studies that splenocytes, transduced with glutamic acid decarboxylase (GAD) 65 fused to immunoglobulin (Ig) G carrier, reduced antibody-mediated response in non-obese diabetic (NOD) mice, here we examined the mechanisms underlying B-cell tolerance in this system. We found that GAD-IgG-transduced splenocytes did not reduce CD40 expression on B-cells in NOD mice, but they did downregulate CD40 ligand (CD40L) expression. Furthermore, anti-CD40L injection reduced autoantibody levels in NOD mice and in vitro experiments demonstrated that CD40L blockade reduced the antigenpresenting capability of B-cells. In conclusion, the results of this study suggest that downregulation of CD40L may be one mechanism underlying the induction of B-cell tolerance in GAD-IgG-treated NOD mice.

Cardiac markers and their point-of-care testing for diagnosis of acute myocardial infarction

Acute myocardial infarction (AMI) is the world's leading cause of mortality and morbidity. Therefore, quick and reliable diagnostics of AMI is extremely critical. Compared to the traditionally used central laboratory tests (CLT), which can be time-consuming and expensive, point-of-care testing (POCT) for AMI-indicative cardiac markers provides a convenient means for rapid diagnostic assays to be performed at the site of patient care delivery. In this article, the etiology and diagnosis of AMI are introduced, and some typical cardiac markers and their clinical applications are reviewed. Furthermore, the various POC cardiac marker devices that are currently available, the benefits of using cardiac marker POC assays, and challenges that cardiac marker POCT are facing are also discussed.

Application of proteomics in cardiovascular medicine

Proteomics is an emerging field that has the potential to uncover new therapeutic targets for the treatment and prevention of cardiovascular disease, as well as new diagnostic biomarkers for early disease detection. The basic strategy when carrying out proteomic analysis of cardiovascular disease is to compare the protein complements of diseased hearts or sera with controls. Any proteins that have altered expression between the two groups can be studied further for their involvement in disease pathogenesis. A number of steps need to be taken to identify changes in protein expression, including sample preparation, protein separation, imaging, and protein identification. Such studies are already underway in some cardiovascular conditions including dilated cardiomyopathy and atrial fibrillation. This review provides a summary of the techniques used in proteomic analysis and their application to cardiovascular research.