Usefulness of rapid quantitative measurement of myoglobin and troponin T in early diagnosis of acute myocardial infarction

Biosensing Platforms for Cardiac Biomarker Detection

Myocardial infarction (MI) is a cardiovascular disease that occurs when there is an elevated demand for myocardial oxygen as a result of the rupture or erosion of atherosclerotic plaques. Globally, the mortality rates associated with MI are steadily on the rise. Traditional diagnostic biomarkers employed in clinical settings for MI diagnosis have various drawbacks, prompting researchers to investigate fast, precise, and highly sensitive biosensor platforms and technologies. Biosensors are analytical devices that combine biological elements with physicochemical transducers to detect and quantify specific compounds or analytes. These devices play a crucial role in various fields including healthcare, environmental monitoring, food safety, and biotechnology. Biosensors developed for the detection of cardiac biomarkers are typically electrochemical, mass, and optical biosensors. Nanomaterials have emerged as revolutionary components in the field of biosensing, offering unique properties that significantly enhance the sensitivity and specificity of the detection systems. This review provides a comprehensive overview of the advancements and applications of nanomaterial-based biosensing systems. Beginning with an exploration of the fundamental principles governing nanomaterials, we delve into their diverse properties, including but not limited to electrical, optical, magnetic, and thermal characteristics. The integration of these nanomaterials as transducers in biosensors has paved the way for unprecedented developments in analytical techniques. Moreover, the principles and types of biosensors and their applications in cardiovascular disease diagnosis are explained in detail. The current biosensors for cardiac biomarker detection are also discussed, with an elaboration of the pros and cons of existing platforms and concluding with future perspectives.

Magnetic nanochains-based dynamic ELISA for rapid and ultrasensitive detection of acute myocardial infarction biomarkers

Acute myocardial infarction (AMI) is the leading cause of morbidity and mortality globally. The serum levels of a group of cardiac biomarkers have been regarded as important indicators in the routine diagnosis of AMI. The development of rapid, sensitive, and accurate detection methods of AMI biomarkers is urgently needed for the early diagnosis of AMI. Here, a dynamic and pseudo-homogeneous enzyme-linked immunosorbent assay (ELISA) was reported based on the combined use of bioconjugated magnetic nanochains (MNCs) and gold nanoparticles (AuNPs) probes. The capture antibodies-conjugated MNCs served as dynamic nano-mixers to facilitate liquid mixing and as homogeneously dispersed capturing agents to capture and separate specific targets. The AuNPs probes were prepared by co-immobilization of detection antibodies and horseradish peroxidase (HRP) for signals amplification. The design of bioconjugated MNCs and AuNPs probes significantly increased the assay kinetics and improves the assay sensitivity. This novel ELISA strategy realized accurate detection of a panel of AMI biomarkers within 35 min, leading to considerably improved sensitivities compared to that of conventional ELISA method.

Heart-Type Fatty Acid Binding Protein: A Better Cardiac Biomarker than CK-MB and Myoglobin in the Early Diagnosis of Acute Myocardial Infarction

BACKGROUND

Early diagnosis and therapeutic intervention can improve the outcome of acute myocardial infarction (AMI). However, there are no satisfactory cardiac biomarkers for the diagnosis of AMI within 6 hours of onset of symptoms. Among novel biochemical markers of AMI, heart-type fatty acid binding protein (H-FABP) is of particular interest.

AIM

To compare the diagnostic value of H-FABP with that of CK-MB and myoglobin in suspected AMI patients within first 6 hours after the onset of symptoms.

SETTINGS AND DESIGN

The study includes 40 AMI cases and 40 non-cardiac chest pain otherwise healthy controls. The cases and controls were further divided into 2 groups depending on the time since chest pain as those subjects within 3 hours and those between 3-6 hours of onset of chest pain.

MATERIALS AND METHODS

In all the cases and controls, serum H-FABP, CK-MB and myoglobin concentrations were measured by Immunoturbidimetric method, immuno-inhibition method and Chemiluminescence immunoassay respectively.

STATISTICAL ANALYSIS

Data is presented as mean ± SD values. Differences between means of two groups were assessed by Student t-test. Sensitivity, Specificity, Positive predictive value, Negative predictive values were calculated and ROC curve analysis was done to assess the diagnostic validity of each study parameter.

RESULTS

The sensitivity, specificity, PPV, NPV of H-FABP were greater than CK-MB and myoglobin and ROC curve analysis demonstrated highest area under curve for H-FABP followed by myoglobin and CK-MB in patients with suspected AMI both within 3 hours and 3-6 hours after the onset of chest pain.

CONCLUSION

The diagnostic efficiency of H-FABP is greater than CK-MB and myoglobin for the early diagnosis of AMI within first 6 hours of chest pain. H-FABP can be used as an additional diagnostic tool for the early diagnosis of AMI.

A Pilot Study on Pain and the Upregulation of Myoglobin through Low-frequency and High-amplitude Electrical Stimulation-induced Muscle Contraction

[Purpose] It is well known that, in both in vivo and in vitro tests, muscle fatigue is produced by severe exercise, electrical stimulation, and so on. However, it is not clear whether or not low-frequency and high-amplitude modulation specifically affects serum myoglobin or urine myoglobin. The purpose of the present study was to determine the effect of low-frequency and high-amplitude modulation on serum myoglobin and urine myoglobin. [Methods] The study used whole blood samples and urine produced over 24 hours from the thirteen healthy subjects. [Results] There was a significant increase in serum myoglobin following electrical stimulation at a frequency of 10 Hz compared with the control group. Furthermore, within 24 hours, urine myoglobin also showed a significant increase for the test volunteers subjected to electrical stimulation at the 10 Hz frequency compared with the control group. However, there were no significant differences in the concentrations of hematologic results in subjects treated with electrical stimulation. [Conclusion] These results suggest that increased myoglobin related to muscle fatigue from electrical stimulation, particularly with a current of 10 Hz combined with a high-amplitude, may be partially related to increased muscle damage.

Early positive biomarker in relation to myocardial necrosis and impaired fatty acid metabolism in patients presenting with acute chest pain at an emergency room

BACKGROUND

Measurement of circulating biomarkers has enabled early diagnosis and risk assessment of acute coronary syndrome. This study sought diagnostic values of the first single-point data of biomarkers obtained soon after patient arrival by comparing with scintigraphically quantified myocardial injury in patients presenting with acute chest pain at an emergency room.

METHODS AND RESULTS

Serial blood samples were taken soon after arrival in an emergency department in 74 patients with suspected acute coronary syndrome to quantify blood levels of troponin-T (TnT), heart-type fatty acid-binding protein (H-FABP), myocardial-bound creatine kinase (CK-MB), and myoglobin. Myocardial perfusion and metabolic defects were scintigraphically quantified. The first single-point data had high positive predictive values for detecting the defects (80-100%) but low negative predictive values (15-41%). CK-MB and TnT had higher specificities (73-100%) but significantly lower positive rates (22-27%) than the others (61-68%), resulting in greater sensitivities of H-FABP and myoglobin (75-80%) than those of CK-MB and TnT (29-35%). Among biomarkers, TnT peak concentrations most closely correlated with scintigraphic abnormalities.

CONCLUSION

H-FABP can contribute to early detection of myocardial injury and TnT is most likely to correlate with injured myocardial mass. The differential features of biomarkers are complementary in patients with acute chest pain presenting at an emergency room.

Serum Cardiac Troponin T in Cardiac Amyloidosis: Serial Observations in Five Patients

The most common cause of death of patients suffering from amyloidosis is heart failure and sudden death, and cardiac troponin T (cTnT), a highly specific and sensitive biomarker of myocardial injury, has been reported to be a prognostic marker at presentation. But the relationship between serial measurements of serum cTnT and clinical course of the disease has not been described. An illustrative case was a 55-year-old man with normal renal function presenting with congestive heart failure (CHF), whose initial concentration of cTnT was 0.72 ng/ml. Eight samples of initial endomyocardial biopsy specimens showed the presence of myocyte degeneration and interstitial fibrosis with a small amount of amyloid infiltration. However, the cTnT values remained at 0.69 ng/ml after successful management of CHF, and four months later, a second endomyocardial biopsy revealed diffuse massive amyloid protein deposition. He died of CHF, 9 months after initial presentation. In addition, we present 4 cases of amyloidosis with increased serum cTnT levels. We therefore propose that serial measurements of serum cTnT might be helpful for early diagnosis and prediction of prognosis of patients with amyloidosis.

Point-of-Care Testing and Cardiac Biomarkers: The Standard of Care and Vision for Chest Pain Centers

Point-of-care testing (POCT) is defined as testing at or near the site of patient care. POCTdecreases therapeutic turnaround time (TTAT), increases clinical efficiency, and improves medical and economic outcomes. TTAT represents the time from test ordering to patient treatment. POC technologies have become ubiquitous in the United States, and, therefore,so has the potential for speed, convenience, and satisfaction, strong advantages for physicians, nurses, and patients in chest pain centers. POCT is applied most beneficially through the collaborative teamwork of clinicians and laboratorians who use integrative strategies, performance maps, clinical algorithms, and care paths (critical pathways). For example, clinical investigators have shown that on-site integration of testing for cardiac injury markers (myoglobin, creatinine kinase myocardial band [CKMB],and cardiac troponin I [cTnI]) in accelerated diagnostic algorithms produces effective screening, less hospitalization, and substantial savings. Chest pain centers, which now total over 150 accredited in the United States, incorporate similar types of protocol-driven performance enhancements. This optimization allows chest pain centers to improve patient evaluation, treatment, survival, and discharge. This article focuses on cardiac biomarker POCT for chest pain centers and emergency medicine.

Relationship between myocardial injury and soluble P-selectin in non-ST elevation acute coronary syndromes

BACKGROUND

The relationships among troponin concentration, early phase coagulation activation and soluble P-selectin concentration was evaluated in this study.

METHODS AND RESULTS

Troponin-l, soluble P-selectin, von Willebrand factor (vWF), fibrinogen, plasminogen, plasminogen activator inhibitor 1 (PAI-1) and tissue plasminogen activator (t-PA) concentrations of 202 consecutive patients with non-ST elevation acute coronary syndrome (NSTE-ACS) were measured at the time of admission. Patients were classified into 2 groups as troponin-negative (<0.2 ng/ml, n=129) or positive (>or=0.2 ng/ml, n=73). Soluble P-selectin concentrations were found to be higher (p<0.001) and correlated with troponin concentrations (r=0.313, p<0.005) in troponin-positive patients with NSTE-ACS. In these patients fibrinogen (p<0.001), plasminogen (p<0.001) and PAI-1 (p<0.026) concentrations were higher and t-PA concentrations were lower (p<0.013) and all these parameters correlated with P-selectin concentrations (p<0.001). There was no difference between the groups according to vWF concentrations (p=0.379). Soluble P-selectin concentrations were found to be an independent predictor of troponin positivity (beta=0.295, odds ratio =1.05, p<0.001). Analysis of regression revealed a significant effect of troponin on soluble P-selectin concentrations (r=0.52, r2=0.27, p<0.001).

CONCLUSIONS

The results suggest that higher soluble P-selectin concentrations might be involved in increased coagulation activation and myocardial injury development in patients with NSTE-ACS.

Impact of the Revised Criteria for Acute Myocardial Infarction Using Cardiac Troponins in a Japanese Population With Acute Coronary Syndromes

BACKGROUND

The clinical implications of applying the new criteria of acute myocardial infarction (AMI) with cardiac troponins in terms of their diagnostic and prognostic impact in patients with suspected acute coronary syndromes (ACS) have not been well evaluated.

METHODS AND RESULTS

The study group comprised 973 consecutive patients who were diagnosed as having ACS with or without ST elevation (STE). They were divided into 3 groups: unstable angina (UA) group (n=195) representing patients with no significant elevations of creatine kinase (CK) and troponin T (TnT); TnT-myocardial infarction (MI) group (n=170) with TnT elevation and no CK elevation (additionally detected AMI by the new criteria); CK-MI group (n=608) with significant elevation of CK (AMI by the old criteria). In the TnT-MI group, 140 (76%) patients had non-STE ACS. In-hospital mortality rates for STE ACS were 0%, 2.5% and 9.7% in the UA, TnT-MI and CK-MI groups, respectively. The corresponding values for non-STE ACS were 1.8%, 4.6%, and 16.5%, respectively (p<0.0001), suggesting a pivotal role of TnT. In multiple logistic regression analysis, significant CK elevation was selected as an independent predictor of in-hospital death in concurrence with age > or =75 years, prior MI, shock and low left ventricular ejection fraction in non-STE ACS.

CONCLUSIONS

The new criteria result in a substantial increase in the diagnosis of AMI from non-STE ACS in particular. They assist greatly in detailed risk stratification of ACS patients, notably in cooperation with the old CK criteria.