The Main Causes and Mechanisms of Increase in Cardiac Troponin Concentrations Other Than Acute Myocardial Infarction (Part 1): Physical Exertion, Inflammatory Heart Disease, Pulmonary Embolism, Renal Failure, Sepsis

Cardiac Troponin Levels in Patients with Chronic Kidney Disease: "Markers of High Risk or Just Noise''?

Kidney disease is linked to the development of cardiovascular disorders, further increasing morbidity and mortality in this high-risk population. Thus, early detection of myocardial damage is imperative in order to prevent devastating cardiovascular complications within this patient group. Over the years, cardiac biomarkers have been identified and are now widely used in everyday clinical practice. More specifically, available data suggest that cardiac troponin and its regulatory subunits (TnT, TnI, and TnC) reflect the injury and necrosis of myocardial tissue. While cTnC is identical in cardiac and skeletal muscle, TnT and TnI constitute cardiac-specific forms of troponin, and, as such, they have been established by international societies as biomarkers of cardiac damage and diagnostic indicators for acute myocardial infarction. Elevations in the levels of both cardiac troponins (cTnT and cTnI) have been also reported in asymptomatic patients suffering from chronic kidney disease. Therefore, if abnormal, they often generate confusion among clinicians regarding the interpretation and clinical significance of their numerical values in emergency settings. The aim of this review is to explore the reasons behind elevated troponin levels in patients with chronic kidney disease and identify when these elevated levels of biomarkers indicate the need for urgent intervention, considering the high cardiovascular risk in this patient group.

Advancements in electrochemical immunosensors towards point-of-care detection of cardiac biomarkers

Cardiovascular disease remains the leading cause of death worldwide, with mortality rates increasing annually. This underscores the urgent need for accurate diagnostic and monitoring tools. Electrochemical detection has emerged as a promising method for swiftly and precisely measuring specific biomarkers in bodily fluids. This approach is not only cost-effective and efficient compared to traditional clinical methods, but it can also be tailored to detect individual biomarkers, which makes it particularly well-suited for point-of-care (POC) applications. The ability to conduct testing at the point of care is crucial for timely interventions and personalized disease management, empowering healthcare providers to tailor treatment plans based on real-time biomarker data. Thanks to recent advancements in nanomaterials, we've seen significant progress in electrochemical detection, leading to the development of specialized rapid immunoassay systems. These systems utilize specific antibodies to target molecules, expanding the range of detectable biomarkers. This innovation has the potential to revolutionize the diagnosis and treatment of cardiovascular diseases by enhancing detection sensitivity and specificity. Ultimately, these advancements aim to improve patient outcomes by enabling earlier diagnosis, more precise monitoring, and personalized therapeutic interventions, which will contribute to more effective management of cardiovascular health globally.

Stroke heart injury: the effect of cerebral reperfusion treatment. A 3-year retrospective study

BACKGROUND

Cardiac involvement following an acute stroke (Stroke Heart Syndrome-SHS) is an established complication and it is linked to the involvement of sympathetic activation, inflammation, and neuro-endocrine response. Troponin "rise and fall pattern" > 30% is one marker of SHS. The aim of this study was to evaluate the role of reperfusion treatments in the prevention/pathogenesis of SHS with different stroke sizes and locations (OCSP classification).

METHODS

We retrospectively analyzed data of 890 patients admitted to the Stroke Unit of Trieste (Italy) between 2018 and 2020. Out of them, 411 met the inclusion criteria (acute ischemic non-lacunar stroke). Clinical data were collected for each patient, imaging characteristics, and markers of cardiac injury [troponin I (TnI), NT-proBNP, "rise and fall pattern" > 30%]. We compared different stroke subtypes according to OCSP, while evaluating any differences in patients with and without SHS.

RESULTS

In treated total anterior circulation infarct (TACI) patients, the rate of SHS is lower than in non-treated TACI. Similar SHS rate was found in partial anterior (PACI) and posterior stroke (POCI), and between treated and non-treated patients. Focusing on TACI group, we compared SHS-TACI and non-SHS-TACI, we performed a univariate and multivariate analysis; treatment (OR 0.408 CI95% 0.185-0.900; p = 0.026) and diabetes (OR 2.618 CI95% 1.181-5.803; p = 0.018) were significantly associated to SHS. No clear insular effect was found in SHS development.

CONCLUSIONS

In severe anterior stroke (TACI), reperfusion treatment may be effective in preventing SHS. Conversely, diabetes is an independent risk factor for SHS. PACI and POCI have similar troponin elevation rate.

Sweroside alleviates pressure overload-induced heart failure through targeting CaMKⅡδ to inhibit ROS-mediated NF-κB/NLRP3 in cardiomyocytes

Ongoing inflammation in the heart is positively correlated with adverse remodeling, characterized by elevated levels of cytokines that stimulate activation of cardiac fibroblasts. It was found that CaMKIIδ response to Ang II or TAC triggers the accumulation of ROS in cardiomyocytes, which subsequently stimulates NF-κB/NLRP3 and leads to an increase in IL-6, IL-1β, and IL-18. This is an important causative factor in the occurrence of adverse remodeling in heart failure. Sweroside is a biologically active natural iridoids extracted from Lonicerae Japonicae Flos. It shows potent anti-inflammatory and antioxidant activity in various cardiovascular diseases. In this study, we found that sweroside inhibited ROS-mediated NF-κB/NLRP3 in Ang II-treated cardiomyocytes by directly binding to CaMKIIδ. Knockdown of CaMKⅡδ abrogated the effect of sweroside regulation on NF-κB/NLRP3 in cardiomyocytes. AAV-CaMKⅡδ induced high expression of CaMKⅡδ in the myocardium of TAC/Ang II-mice, and the inhibitory effect of sweroside on TAC/Ang Ⅱ-induced elevation of NF-κB/NLRP3 was impeded. Sweroside showed significant inhibitory effects on CaMKIIδ/NF-κB/NLRP3 in cardiomyocytes from TAC/Ang Ⅱ-induced mice. This would be able to mitigate the adverse events of myocardial remodeling and contractile dysfunction at 8 weeks after the onset of the inflammatory response. Taken together, our findings have revealed the direct protein targets and molecular mechanisms by which sweroside improves heart failure, thereby supporting the further development of sweroside as a therapeutic agent for heart failure.

Adverse cardiac events of hypercholesterolemia are enhanced by sitagliptin in sprague dawley rats

BACKGROUND

Cardiovascular disease (CVD) affects millions worldwide and is the leading cause of death among non-communicable diseases. Western diets typically comprise of meat and dairy products, both of which are rich in cholesterol (Cho) and methionine (Met), two well-known compounds with atherogenic capabilities. Despite their individual effects, literature on a dietary combination of the two in the context of CVD are limited. Therefore, studies on the combined effects of Cho and Met were carried out using male Sprague Dawley rats. An additional interest was to investigate the cardioprotective potential of sitagliptin, an anti-type 2 diabetic drug. We hypothesized that feeding a dietary combination of Cho and Met would result in adverse cardiac effects and would be attenuated upon administration of sitagliptin.

METHODS

Adult male Sprague-Dawley rats were fed either a control (Con), high Met (1.5%), high Cho (2.0%), or high Met (1.5%) + high Cho (2.0%) diet for 35 days. They were orally gavaged with an aqueous preparation of sitagliptin (100 mg/kg/d) or vehicle (water) from day 10 through 35. On day 36, rats were euthanized, and tissues were collected for analysis.

RESULTS

Histopathological evaluation revealed a reduction in myocardial striations and increased collagen deposition in hypercholesterolemia (HChol), responses that became exacerbated upon sitagliptin administration. Cardiac pro-inflammatory and pro-fibrotic responses were adversely impacted in similar fashion. The addition of Met to Cho (MC) attenuated all adverse structural and biochemical responses, with or without sitagliptin.

CONCLUSIONS

Adverse cardiac outcomes in HChol were enhanced by the administration of sitagliptin, and such effects were alleviated by Met. Our findings could be significant for understanding or revisiting the risk-benefit evaluation of sitagliptin in type 2 diabetics, and especially those who are known to consume atherogenic diets.

The Role of High-Sensitivity Troponin T Regarding Prognosis and Cardiovascular Outcome across Heart Failure Spectrum

Background: Cardiac troponin release is related to the cardiomyocyte loss occurring in heart failure (HF). The prognostic role of high-sensitivity cardiac troponin T (hs-cTnT) in several settings of HF is under investigation. The aim of the study is to assess the prognostic role of intrahospital hs-cTnT in patients admitted due to HF. Methods: In this observational, single center, prospective study, patients hospitalized due to HF have been enrolled. Admission, in-hospital peak, and discharge hs-cTnT have been assessed. Patients were followed up for 6 months. Cardiovascular (CV) death, HF hospitalization (HFH), and worsening HF (WHF) (i.e., urgent ambulatory visit/loop diuretics escalation) events have been assessed at 6-month follow up. Results: 253 consecutive patients have been enrolled in the study. The hs-cTnT median values at admission and discharge were 0.031 ng/mL (IQR 0.02-0.078) and 0.031 ng/mL (IQR 0.02-0.077), respectively. The risk of CV death/HFH was higher in patients with admission hs-cTnT values above the median (p = 0.02) and in patients who had an increase in hs-cTnT during hospitalization (p = 0.03). Multivariate Cox regression analysis confirmed that hs-cTnT above the median (OR: 2.06; 95% CI: 1.02-4.1; p = 0.04) and increase in hs-cTnT during hospitalization (OR:1.95; 95%CI: 1.006-3.769; p = 0.04) were predictors of CV death/HFH. In a subgroup analysis of patients with chronic HF, hs-cTnT above the median was associated with increased risk of CV death/HFH (p = 0.03), while in the subgroup of patients with HFmrEF/HFpEF, hs-cTnT above the median was associated with outpatient WHF events (p = 0.03). Conclusions: Inpatient hs-cTnT levels predict CV death/HFH in patients with HF. In particular, in the subgroup of chronic HF patients, hs-cTnT is predictive of CV death/HFH; while in patients with HFmrEF/HFpEF, hs-cTnT predicts WHF events.

Biobanks in chronic disease management: A comprehensive review of strategies, challenges, and future directions

Biobanks, through the collection and storage of patient blood, tissue, genomic, and other biological samples, provide unique and rich resources for the research and management of chronic diseases such as cardiovascular diseases, diabetes, and cancer. These samples contain valuable cellular and molecular level information that can be utilized to decipher the pathogenesis of diseases, guide the development of novel diagnostic technologies, treatment methods, and personalized medical strategies. This article first outlines the historical evolution of biobanks, their classification, and the impact of technological advancements. Subsequently, it elaborates on the significant role of biobanks in revealing molecular biomarkers of chronic diseases, promoting the translation of basic research to clinical applications, and achieving individualized treatment and management. Additionally, challenges such as standardization of sample processing, information privacy, and security are discussed. Finally, from the perspectives of policy support, regulatory improvement, and public participation, this article provides a forecast on the future development directions of biobanks and strategies to address challenges, aiming to safeguard and enhance their unique advantages in supporting chronic disease prevention and treatment.

Additional Benefits of Serum Oncostatin M Levels Compared to Cardiac Troponin in Non-ST Elevation Myocardial Infarction

Background

The use of high-sensitivity troponin levels increases the sensitivity of the diagnosis of non-ST elevation myocardial infarction (NSTEMI). However, the inclusion of other factors in the differential diagnosis, apart from atherothrombosis causing myocardial injury, decreases the specificity of high-sensitivity troponin. In this study, we compared the efficacy of high-sensitivity troponin with serum oncostatin M in NSTEMI cases with elevated urea and creatinine.

Methods

This study was performed with a prospective cross-sectional sample. Ninety participants with coronary angiography performed due to a preliminary diagnosis of NSTEMI were included. High-sensitivity troponin I, creatine kinase-MB, lactate dehydrogenase, serum transaminase and oncostatin M levels were quantitatively measured for the first 4-8 hours from the onset of symptoms. All participants had coronary angiography performed within the first 12 hours after attending the emergency service. Based on coronary angiography data, patients with significant coronary stenosis or occlusion detected during coronary angiography were defined as group A, and patients with no occlusion in the coronary artery and who did not require an additional interventional procedure were defined as group B. The SYNTAX 2 score was used to determine the severity of coronary artery disease.

Results

Patients in both groups A and B had similar age, sex distribution and comorbidities. Group A had higher serum urea, creatinine, oncostatin M and high-sensitivity troponin I values than group B. With 585 pg/ml as the cut-off value, serum oncostatin M had a sensitivity of 88.6% and specificity of 85% for the diagnosis of NSTEMI. Logistic regression multivariate analysis showed that serum oncostatin M and high-sensitivity troponin I values had diagnostic efficacy for NSTEMI. Serum oncostatin M was found to be more effective than high-sensitivity troponin I in patients with elevated urea and creatinine.

Conclusions

Serum oncostatin M had similar sensitivity and specificity for NSTEMI diagnosis as high-sensitivity troponin I. Serum OSM can especially be considered as a complementary diagnostic biomarker for NSTEMI in patients with renal dysfunction.

Beyond the fractures: A comprehensive Comparative analysis of Affordable and Accessible laboratory parameters and their coefficients for prediction and Swift confirmation of pulmonary embolism in high-risk orthopedic patients

Background

Pulmonary embolism (PE) poses a significant challenge in diagnosis and treatment, particularly in high-risk patient populations such as those hospitalized for orthopedic reasons. This study explores the predictive and diagnostic potential of laboratory parameters in identifying PE among orthopedic patients.

Objectives

The purpose of this study was to determine whether selected (inexpensive and readily available) laboratory parameters and their coefficients can be used to diagnose pulmonary embolism and whether they are applicable in predicting its occurrence.

Material and methods

Selected laboratory parameters were determined twice in 276 hospitalized orthopedic patients with suspected PE: PLT, MPV, NEU, LYM, D-dimer, troponin I, age-adjusted D-dimer and their coefficients. Depending on the angio-CT results, patients were divided into groups. Selected popular laboratory coefficients were calculated and statistically analyzed. Optimal cutoff points were determined for the above laboratory tests and ROC curves were plotted.

Results

D-dimer/troponin I [p = 0.008], D-dimer [p = 0.001], age-adjusted D-dimer [p = 0.007], NLR/D-dimer [p = 0.005] and PLR [p = 0.021] are statistically significant predictors of PE. D-dimer/troponin I [p < 0.001], troponin I [p = 0.005] and age-adjusted D-dimer [p = 0.001] correlated with the diagnosis of PE after the onset of clinical symptoms.

Conclusions

In the context of orthopedic patients, cost-effective laboratory parameters, particularly the D-dimer/troponin I ratio and age-adjusted D-dimer, exhibit considerable potential in predicting and diagnosing PE. These findings suggest that combining readily available laboratory tests with clinical observation can offer a viable and cost-effective diagnostic alternative, especially in resource-constrained settings. Further studies with larger and diverse patient populations are recommended to validate these results.

Torsades de pointes and myocardial infarction following reversal of supraventricular tachycardia with adenosine: a case report

Adenosine is an antiarrhythmic drug that slows conduction through the atrioventricular node and acts as a coronary blood vessel dilator. This case report highlights two unusual life-threatening events following the use of adenosine to revert supraventricular tachycardia in a structurally normal heart: non-sustained polymorphic ventricular tachycardia and myocardial infarction. A 46-year-old woman presented to the emergency department with a two-hour history of palpitations and was diagnosed with supraventricular tachycardia. Vagal maneuvers were ineffective, and after intravenous adenosine administration, the patient presented with chest pain and hypotension. The rhythm degenerated into non-sustained polymorphic ventricular tachycardia and spontaneously reverted to sinus rhythm with ST elevation in lead aVR and ST depression in the inferior and anterolateral leads. The patient spontaneously recovered within a few minutes. Despite successful arrhythmia reversal, the patient was admitted to the intensive care unit because of an infarction without obstructive atherosclerosis. This report aims to alert emergency physicians about the potential complications associated with supraventricular tachycardia and its reversal with adenosine.

Intraoperative Catastrophic Acute Pulmonary Embolism: A Case Report

This case report describes a 75-year-old female with a medical history including recurrent bowel obstruction due to sigmoid stricture, atrial fibrillation managed with rivaroxaban, a 50-year one pack-per-day smoking history, hypertension, hyperlipidemia, peripheral vascular disease with bilateral iliac stents (2015), stage III chronic kidney disease, and renal artery stenosis with bilateral stenting. She was transferred from outside hospital for an elective sigmoidectomy with ileorectal anastomosis following several recent admissions due to bowel obstruction that had been managed non-operatively. She was deemed optimized for surgery by the primary care team; however, during induction, she developed pulseless ventricular tachycardia requiring extensive resuscitative efforts. Intraoperative findings revealed biventricular failure and a clot in the right pulmonary artery. Despite aggressive treatment, including veno-arterial extracorporeal membrane oxygenation (VA ECMO), the patient's condition deteriorated, and life support was ultimately withdrawn. This case highlights the challenges of managing complex surgical patients and underscores the importance of multidisciplinary care in such cases.

Clinical Interpretation of Serum Troponin in the Era of High-Sensitivity Testing

Cardiac troponin (Tn) plays a central role in the evaluation of patients with angina presenting with acute coronary syndrome. The advent of high-sensitivity assays has improved the analytic sensitivity and precision of serum Tn measurement, but this advancement has come at the cost of poorer specificity. The role of clinical judgment is of heightened importance because, more so than ever, the interpretation of serum Tn elevation hinges on the careful integration of findings from electrocardiographic, echocardiographic, physical exam, interview, and other imaging and laboratory data to formulate a weighted differential diagnosis. A thorough understanding of the epidemiology, mechanisms, and prognostic implications of Tn elevations in each cardiac and non-cardiac etiology allows the clinician to better distinguish between presentations of myocardial ischemia and myocardial injury-an important discernment to make, as the treatment of acute coronary syndrome is vastly different from the workup and management of myocardial injury and should be directed at the underlying cause.

Basic and translational mechanisms in inflammatory arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is a familial, nonischemic heart disease typically inherited via an autosomal dominant pattern (Nava et al., [1]; Wlodarska et al., [2]). Often affecting the young and athletes, early diagnosis of ACM can be complicated as incomplete penetrance with variable expressivity are common characteristics (Wlodarska et al., [2]; Corrado et al., [3]). That said, of the five desmosomal genes implicated in ACM, pathogenic variants in desmocollin-2 (DSC2) and desmoglein-2 (DSG2) have been discovered in both an autosomal-recessive and autosomal-dominant pattern (Wong et al., [4]; Qadri et al., [5]; Chen et al., [6]). Originally known as arrhythmogenic right ventricular dysplasia (ARVD), due to its RV prevalence and manifesting in the young, the disease was first described in 1736 by Giovanni Maria Lancisi in his book "De Motu Cordis et Aneurysmatibus" (Lancisi [7]). However, the first comprehensive clinical description and recognition of this dreadful disease was by Guy Fontaine and Frank Marcus in 1982 (Marcus et al., [8]). These two esteemed pathologists evaluated twenty-two (n = 22/24) young adult patients with recurrent ventricular tachycardia (VT) and RV dysplasia (Marcus et al., [8]). Initially, ARVD was thought to be the result of partial or complete congenital absence of ventricular myocardium during embryonic development (Nava et al., [9]). However, further research into the clinical and pathological manifestations revealed acquired progressive fibrofatty replacement of the myocardium (McKenna et al., [10]); and, in 1995, ARVD was classified as a primary cardiomyopathy by the World Health Organization (Richardson et al., [11]). Thus, now classifying ACM as a cardiomyopathy (i.e., ARVC) rather than a dysplasia (i.e., ARVD). Even more recently, ARVC has shifted from its recognition as a primarily RV disease (i.e., ARVC) to include left-dominant (i.e., ALVC) and biventricular subtypes (i.e., ACM) as well (Saguner et al., [12]), prompting the use of the more general term arrhythmogenic cardiomyopathy (ACM). This review aims to discuss pathogenesis, clinical and pathological phenotypes, basic and translational research on the role of inflammation, and clinical trials aimed to prevent disease onset and progression.

Xijiao Dihuang Decoction Protects Against Murine Sepsis-Induced Cardiac Inflammation and Apoptosis via Suppressing TLR4/NF-κB and Activating PI3K/AKT Pathway

Background

Xijiao Dihuang decoction (XJDHT), a traditional Chinese medicine, is widely used to treat patients with sepsis. However, the mechanisms underlying the effects of XJDHT on cardiac dysfunction have yet to be fully elucidated. The present study evaluated the potential utility of XJDHT in protecting against sepsis-induced cardiac dysfunction and myocardial injury.

Methods

The mice were randomly divided into 3 groups and administered Lipopolysaccharide (LPS,10 mg/kg) or equivalent saline solution (control) and treated with XJDHT (10 g/kg/day) or saline by gavage for 72 hours. XJDHT was dissolved in 0.9% sodium chloride and administered at 200 μL per mouse. Transthoracic echocardiography, RNA-seq, TUNEL assays and hematoxylin and eosin (H&E) staining of cardiac tissues were performed.

Results

Treatment with XJDHT significantly enhanced myocardial function and attenuated pathological change, infiltration of inflammatory cells, levels of TNF-α, IL-1β and expression of TLR4 and NF-κB in mice with sepsis. RNA sequencing and Kyoto Encyclopedia of Genes and Genomes pathway analyses identified 531 differentially expressed genes and multiple enriched signaling pathways including the PI3K/AKT pathway. Further, XJDHT attenuated cardiac apoptosis and decreased Bax protein expression while increasing protein levels of Bcl-2, PI3K, and p-AKT in cardiac tissues of mice with sepsis.

Conclusion

In summary, XJDHT improves cardiac function in a murine model of sepsis by attenuating cardiac inflammation and apoptosis via suppressing the TLR4/NF-κB pathway and activating the PI3K/AKT pathway.

Cardiovascular Biomarkers in Cardio-Oncology: Antineoplastic Drug Cardiotoxicity and Beyond

Serum biomarkers represent a reproducible, sensitive, minimally invasive and inexpensive method to explore possible adverse cardiovascular effects of antineoplastic treatments. They are useful tools in risk stratification, the early detection of cardiotoxicity and the follow-up and prognostic assessment of cancer patients. In this literature review, we aim at describing the current state of knowledge on the meaning and the usefulness of cardiovascular biomarkers in patients with cancer; analyzing the intricate relationship between cancer and cardiovascular disease (especially HF) and how this affects cardiovascular and tumor biomarkers; exploring the role of cardiovascular biomarkers in the risk stratification and in the identification of chemotherapy-induced cardiotoxicity; and providing a summary of the novel potential biomarkers in this clinical setting.

LncRNA NEAT1/miR-211/IL-10 Axis Regulates Inflammation of Peripheral Blood Mononuclear Cells in Acute Myocardial Infarction

This study aimed to explore the expression of long non-coding RNA (lncRNA) nuclear paraspeckle assembly transcript 1 (NEAT1) in patients with acute myocardial infarction (AMI) and its inflammatory regulation mechanism through miR-211/interleukin 10 (IL-10) axis.A total of 75 participants were enrolled in this study: 25 healthy people in the control group, 25 patients with stable angina pectoris (SAP) in the SAP group, and 25 patients with AMI in the AMI group. Real-time qPCR was used to detect mRNA expression levels of NEAT1, miR-211, and IL-10. The interaction between miR-211, NEAT1, and IL-10 was confirmed by dual-luciferase reporter assay, and protein expression was detected using western blot.High expression of NEAT1 in peripheral blood mononuclear cells (PBMCs) of patients with AMI was negatively related to serum creatine kinase-MB (CK-MB), cardiac troponin I (cTnI), tumor necrosis factor-α (TNF-α), IL-6, and IL-1β and was positively correlated with left ventricular ejection fraction (LVEF). In THP-1 cells, miR-211 was confirmed to target and inhibit IL-10 expression. NEAT1 knockdown and miR-211-mimic markedly decreased IL-10 protein levels, whereas anti-miR-211 markedly increased IL-10 protein levels. Importantly, miR-211 level was negatively related to NEAT1 and IL-10 levels, whereas IL-10 level was positively related to the level of NEAT1 expression in PBMCs of patients with AMI.LncRNA NEAT1 was highly expressed in PBMCs of patients with AMI, and NEAT1 suppressed inflammation via miR-211/IL-10 axis in PBMCs of patients with AMI.

Elevated high-sensitivity cardiac troponin T serum concentration in subjects with spinal cord injury

BACKGROUND

The biochemical analysis of high-sensitivity cardiac troponins (hs-cTn) from peripheral blood specimens has been established as biomarker for myocardial injury. Independently of myocardial injury, increased serum hs-cTn concentrations have been described in patients with myopathies. The relevance and frequency of noncardiac hs-cTn elevations in spinal cord injury (SCI) is unknown. Our study aimed to 1) determine the frequency of increased hs-cTn concentrations of supposedly noncardiac origin above the 99th percentile (upper reference limit, URL) in an unselected SCI population and 2) compare the two protagonist analytes cTnT and cTnI with respect to these noncardiac elevations.

METHODS

In this monocentric, cross-sectional study, we sampled blood from n = 30 SCI subjects without cardiac symptoms to test for hs-cTnT and hs-cTnI serum concentrations.

RESULTS

18/30 (60%) of SCI subjects showed increased hs-cTnT concentrations above the URL of 14 ng/l (p < 0.001). In 4 subjects (22.2%) concentrations were >50 ng/l. Moreover, 3 of these four subjects fulfilled the 6-h troponin dynamics criterion for acute myocardial injury in serial hs-cTnT testing. In contrast, no subject demonstrated increased hs-cTnI concentrations according to the URL of 40 ng/l. 6-h troponin dynamics were also unremarkable for hs-cTnI testing.

CONCLUSIONS

SCI subjects frequently have increased hs-cTnT concentrations without clinical and hs-cTnI evidence of myocardial injury. Clinicians must be aware of cTnT "skeletal muscle false-positives" in SCI, which applies to elevated baseline cTnT concentrations and troponin dynamics in serial measurements. In case of diagnostic uncertainty, simultaneous analysis of cTnI might be helpful.

The Essential Strategies to Mitigate Cardiotoxicity Caused by Doxorubicin

The study of mechanisms underlying cardiotoxicity of doxorubicin and the development of strategies to mitigate doxorubicin-induced cardiotoxicity are the most relevant issues of modern cardio-oncology. This is due to the high prevalence of cancer in the population and the need for frequent use of highly effective chemotherapeutic agents, in particular anthracyclines, for optimal management of cancer patients. However, while being a potent agent to counteract cancer, doxorubicin also affects the cardiovascular systems of patients undergoing chemotherapy in a significant and unfavorable fashion. Consecutively reviewed in this article are risk factors and mechanisms of doxorubicin cardiotoxicity, and the essential strategies to mitigate cardiotoxic effects of doxorubicin treatment in cancer patients are discussed.

Rifampicin efficacy against doxorubicin-induced cardiotoxicity in mice

BACKGROUND

The toxic effect of doxorubicin on the heart limits its clinical usage in cancer therapy. This work intended to investigate, for the first time, the efficacy of rifampicin administration against doxorubicin-induction of cardiotoxicity in mice. Forty adult male albino mice were distributed into four sets: Control, Doxorubicin, Doxorubicin + Rifampicin 0.107, and Doxorubicin + Rifampicin 0.214, with n = 10 for each. Heart histopathology and biochemical assays for heart function tests [creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), cardiac troponin I (cTnI), atrial natriuretic peptide (ANP), and vascular endothelial growth factor (VEGF)], oxidative stress [malondialdehyde (MDA) and superoxide dismutase (SOD)], and minerals [phosphorus, sodium, potassium, and calcium] were done.

RESULTS

Doxorubicin-induced cardiotoxicity using a total dose of 15 mg/kg was confirmed histologically. Cardiomyocytes showed congestion, necrosis, edema, and inflammatory cell infiltration. Biochemically, elevations in LDH, CK, and AST activities, p < 0.001, as well as increases in cTnI and ANP levels, p < 0.001, increased oxidative stress (MDA, p < 0.001), high minerals (Na, K, p < 0.001, P, p < 0.01, and Ca, p < 0.05), with reduced VEGF concentration, p < 0.001, and low antioxidant (SOD, p < 0.001) were observed in the Doxorubicin group compared to control. Co-treatment with rifampicin significantly (p < 0.001) reduced the increased oxidative stress, high Na and K, increased LDH, CK, AST, cTnI, and ANP, and elevated the low SOD toward the normal ranges. Our histological data supported our biochemical data; rifampicin dose 0.214 mg/kg showed better improvements than dose 0107.

CONCLUSIONS

Our results demonstrated that rifampicin could help protect the body against doxorubicin-induced cardiotoxicity through its antioxidative effect.

The Role of Congestion Biomarkers in Heart Failure with Reduced Ejection Fraction

In heart failure with reduced ejection fraction, edema and congestion are related to reduced cardiac function. Edema and congestion are further aggravated by chronic kidney failure and pulmonary abnormalities. Furthermore, together with edema/congestion, sodium/water retention is an important sign of the progression of heart failure. Edema/congestion often anticipates clinical symptoms, such as dyspnea and hospitalization; it is associated with a reduced quality of life and a major risk of mortality. It is very important for clinicians to predict the signs of congestion with biomarkers and, mainly, to understand the pathophysiological findings that underlie edema. Not all congestions are secondary to heart failure, as in nephrotic syndrome. This review summarizes the principal evidence on the possible roles of the old and new congestion biomarkers in HFrEF patients (diagnostic, prognostic, and therapeutic roles). Furthermore, we provide a description of conditions other than congestion with increased congestion biomarkers, in order to aid in reaching a differential diagnosis. To conclude, the review focuses on how congestion biomarkers may be affected by new HF drugs (gliflozins, vericiguat, etc.) approved for HFrEF.

Risk stratification of patients with chest pain who have an unscheduled revisit to the emergency department

AIMS

Acute cardiovascular (CV) emergencies are critical conditions that require urgent attention in the emergency department (ED). Failure to make a timely diagnosis may result in unscheduled ED revisits and severe outcomes. Therefore, this study aimed to investigate the risk factors associated with potentially missed acute CV emergencies.

METHODS AND RESULTS

This retrospective study enrolled adult patients who presented with chest pain and returned to the ED within 72 h. Demographic information, pre-existing medical conditions, chief complaints, triage level and vital signs, electrocardiography (ECG) reports, and laboratory data were collected from medical charts by independent physicians. The primary outcome was the diagnosis of acute CV diseases, including ACS, pulmonary embolism, unstable arrhythmia, acute decompensated heart failure, and aortic dissection. Multivariable logistic regression was used to analyze the association between variables and acute CV emergencies. A total of 453 eligible patients were included, with 60 (13.2%) patients diagnosed as acute CV emergencies at the ED revisit. Risk factors for acute CV emergencies included male gender (adjusted odds ratio [aOR] = 2.71, 95% confidence interval [CI] = 1.17-6.25), abnormal ECG rhythm (aOR = 10.33, 95% CI = 4.68-22.83), and abnormal changes in high sensitivity Troponin-T (hs-cTnT) during sequential follow-up (aOR = 6.52, 95% CI = 2.19-19.45).

CONCLUSIONS

Male gender, abnormal ECG rhythm, and a significant increase in sequential follow-up hs-cTnT levels were identified as significant risk factors for acute CV emergencies. ED physicians should recognize these high-risk patients with chest pain to prevent misdiagnosis and potential severe complications.

Biomarkers as Prognostic Predictors and Therapeutic Guide in Critically Ill Patients: Clinical Evidence

A biomarker is a molecule that can be measured in a biological sample in an objective, systematic, and precise way, whose levels indicate whether a process is normal or pathological. Knowing the most important biomarkers and their characteristics is the key to precision medicine in intensive and perioperative care. Biomarkers can be used to diagnose, in assessment of disease severity, to stratify risk, to predict and guide clinical decisions, and to guide treatments and response to them. In this review, we will analyze what characteristics a biomarker should have and how to ensure its usefulness, and we will review the biomarkers that in our opinion can make their knowledge more useful to the reader in their clinical practice, with a future perspective. These biomarkers, in our opinion, are lactate, C-Reactive Protein, Troponins T and I, Brain Natriuretic Peptides, Procalcitonin, MR-ProAdrenomedullin and BioAdrenomedullin, Neutrophil/lymphocyte ratio and lymphopenia, Proenkephalin, NefroCheck, Neutrophil gelatinase-associated lipocalin (NGAL), Interleukin 6, Urokinase-type soluble plasminogen activator receptor (suPAR), Presepsin, Pancreatic Stone Protein (PSP), and Dipeptidyl peptidase 3 (DPP3). Finally, we propose an approach to the perioperative evaluation of high-risk patients and critically ill patients in the Intensive Care Unit (ICU) based on biomarkers.

Gender Specificities of Cardiac Troponin Serum Levels: From Formation Mechanisms to the Diagnostic Role in Case of Acute Coronary Syndrome

Cardiac troponins T and I are the main (most sensitive and specific) laboratory indicators of myocardial cell damage. A combination of laboratory signs of myocardial cell damage (elevated levels of cardiac troponins T and I) with clinical (severe chest pain spreading to the left side of the human body) and functional (rise or depression of the ST segment, negative T wave or emergence of the Q wave according to electrocardiography and/or decrease in the contractility of myocardial areas exposed to ischemia according to echocardiography) signs of myocardial ischemia is indicative of the ischemic damage to cardiomyocytes, which is characteristic of the development of acute coronary syndrome (ACS). Today, with early diagnostic algorithms for ACS, doctors rely on the threshold levels of cardiac troponins (99th percentile) and on the dynamic changes in the serum levels over several hours (one, two, or three) from the moment of admission to the emergency department. That said, some recently approved highly sensitive methods for determining troponins T and I show variations in 99th percentile reference levels, depending on gender. To date, there are conflicting data on the role of gender specificities in the serum levels of cardiac troponins T and I in the diagnostics of ACS, and the specific mechanisms for the formation of gender differences in the serum levels of cardiac troponins T and I are unknown. The purpose of this article is to analyze the role of gender specificities in cardiac troponins T and I in the diagnostics of ACS, and to suggest the most likely mechanisms for the formation of differences in the serum levels of cardiac troponins in men and women.

Modern Concepts of the Role of Fine Particles (PM 2.5) in the Genesis of Atherosclerosis and Myocardial Damage: Clinical and Epidemiological Data, the Main Pathophysiological Mechanisms

Due to the fact that atherosclerotic cardiovascular diseases (CVDs) dominate in the structure of morbidity, disability and mortality of the population, the study of the risk factors for the development of atherosclerotic CVDs, as well as the study of the underlying pathogenetic mechanisms thereof, is the most important area of scientific research in modern medicine. Understanding these aspects will allow improving the set of treatment and preventive measures and activities. One of the important risk factors for the development of atherosclerosis, which has been actively studied recently, is air pollution with fine particulate matter (PM 2.5). According to clinical and epidemiological data, the level of air pollution with PM 2.5 exceeds the normative indicators in most regions of the world and is associated with subclinical markers of atherosclerosis and mortality from atherosclerotic CVDs. The aim of this article is to systematize and discuss in detail the role of PM 2.5 in the development of atherosclerosis and myocardial damage with the consideration of epidemiological and pathogenetic aspects. Materials and Methods: This narrative review is based on the analysis of publications in the Medline, PubMed, and Embase databases. The terms "fine particles" and "PM 2.5" in combination with "pathophysiological mechanisms," "cardiovascular diseases", "atherosclerosis", "cardiac troponins", "myocardial damage" and "myocardial injury" were used to search publications. Conclusion: According to the conducted narrative review, PM 2.5 should be regarded as the significant risk factor for the development of atherosclerotic CVDs. The pro-atherogenic effect of fine particulate matter is based on several fundamental and closely interrelated pathophysiological mechanisms: endothelial dysfunction, impaired lipid metabolism, increased oxidative stress and inflammatory reactions, impaired functioning of the vegetative nervous system and increased activity of the hemostatic system. In addition, PM 2.5 causes subclinical damage to cardiac muscle cells by several mechanisms: apoptosis, oxidative stress, decreased oxygen delivery due to coronary atherosclerosis and ischemic damage of cardiomyocytes. Highly sensitive cardiac troponins are promising markers for detecting subclinical myocardial damage in people living in polluted regions.

The Correlation Between Cardiac Oxidative Stress and Inflammatory Cytokine Response Following Myocardial Infarction

Our study was conducted to investigate the potential correlation between cardiac oxidative stress and inflammatory cytokine response following myocardial infarction. A total of 120 patients harboring acute myocardial infarction who underwent percutaneous coronary intervention (PCI) at our hospital were included. Their general clinical data were analyzed, and comparisons were made regarding the levels of inflammatory factors, oxidative stress markers, heart pump function, and cardiac function. The correlation between cardiac oxidative stress and inflammatory cytokine response was assessed using Pearson's linear correlation. Following treatment, significant reductions were seen in the serum levels of cortisol, thyroid-stimulating hormone (TSH), B-type natriuretic peptide (BNP), C-reactive protein (CRP), signal transducer and activator of transcription 3 (STAT3), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor (TNF), and catalase (CAT) compared to pre-treatment levels. Conversely, the levels of growth hormone (GH), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), cardiac output (CO), and cardiac index (CI) were significantly elevated. Serum cortisol (r = 0.481, P = .001), BNP (r = 0.437, P = .001), CRP (r = 0.542, P = .001), STAT3 (r = 0.835, P = .001), TSH (P = .001), IL-8 (r = 0.867, P = .001), TNF-α (r = 0.439, P = .001), and cardiac oxidative stress demonstrated significantly positive correlations (P < .05). Additionally, a significant negative correlation was found between GH (r = -0.654, P = .001) and immune balance (P < .05). This study evaluated the severity of myocardial infarction using indicators such as CO and CI. This study found a significant correlation between cardiac oxidative stress and inflammatory cytokines after myocardial infarction, suggesting their potential as predictors of myocardial infarction severity.

Association between troponin and outcome in patients with chest pain and rapid atrial fibrillation: a retrospective study of a single-center 10-year cohort

BACKGROUND AND OBJECTIVE

The prognosis of myocardial infarction in patients with rapid atrial fibrillation (RAF) is poorly known. We sought to ascertain if troponin concentrations are associated with a higher risk of major adverse cardiovascular events (MACE) in patients with RAF and chest discomfort suggestive of coronary origin.

METHODS

We retrospectively reviewed all consecutive patients attending an emergency department of a single-center (2008-2017) with chest pain suggestive of coronary origin who had RAF and at least one troponin determination. Patients were classified as having normal/increased troponin. They were followed until December 2019 to detect MACE (primary outcome), which included acute coronary syndrome (ACS), revascularization, stroke, or all-cause death. In addition to cardiovascular death and type I myocardial infarction, these were considered secondary outcomes. The adjusted risk was determined by Cox regression, and sensitivity analysis were run. Relationship between troponin as a continuous variable and outcomes was also evaluated, as well as interaction by sex.

RESULTS

We included 574 patients (median = 76.5 years, IQR = 14, women 56.8%, increased troponin 34.1%) followed by a median of 3.8 years (IQR = 4.8). MACE occurred in 200 patients (34.8%). Increased troponin was independently associated with MACE (adjusted hazard ratio, 1.502, 95% CI, 1.130-1.998), ACS (adjusted hazard ratio, 2.488, 95% CI, 1.256-4.928), type I myocardial infarction (adjusted hazard ratio, 2.771, 95% CI, 1.212-6.333) and stroke (adjusted hazard ratio, 3.580, 95% CI, 1.888-6.787) but not with death, cardiovascular death or revascularization. Sensitivity analyses were consistent with these results. There was no interaction by sex. When assessed continuously, an increase in troponin concentrations was lineally associated with a steady increase in the risk of MACE.

CONCLUSIONS

In patients with RAF who complain of chest pain, increased troponin levels are related to adverse cardiovascular outcomes.

Review of Recent Laboratory and Experimental Data on Cardiotoxicity of Statins

Due to the fact that statins are among the most high-demand therapeutic agents used for the treatment and prevention of the most common cardiovascular diseases, a significant amount of research is focused on these drugs. As a result, the study and discovery of new effects in statin drugs continues. Research methods are constantly being improved in terms of their sensitivity and specificity, which leads to a change in ideas. In addition to the main lipid-lowering effect, statins have a number of additional effects, which can be conditionally divided into positive (pleiotropic) and negative (side effects). Moreover, information about many of the pleiotropic effects of statins is controversial and may subsequently change as new data become available. To a large extent, this is due to the introduction of new and the improvement of old methods of study: clinical, laboratory and morphological ones. Recent studies report the possibility of statins having potential cardiotoxic properties, which is expressed by an increase in the concentration of highly sensitive cardiac troponins, as well as various adverse changes in cardiac myocytes at the ultrastructural and molecular levels. This paper discusses possible mechanisms of statin cardiotoxicity. This narrative review is based on an analysis of publications in the Medline, PubMed, PubMed Central and Embase databases. The terms "statins", "troponin", "troponin I", "troponin T" in combination with "cardiotoxicity", "false positive", "mechanisms of increase", "pathophysiological mechanisms", "oxidative stress" and "cardiomyocyte apoptosis" were used to search publications.

Hypertension as One of the Main Non-Myocardial Infarction-Related Causes of Increased Cardiospecific Troponins: From Mechanisms to Significance in Current Medical Practice

It is well known that many pathological conditions of both cardiovascular diseases (CVDs) (coronary heart disease, myocardial infarction, arrhythmias, myocarditis, cardiomyopathy, etc.) and non-cardiac (sepsis, anemia, kidney diseases, diabetes mellitus, etc.) origin in the course of their development cause injury to contractile cardiac muscle cells - myocardial cells (MCs). One of the most sensitive and specific criteria for detecting MC injury are cardiospecific troponins (CTs), which are regulatory protein molecules that are released into the blood serum from MC upon their death or injury. Current methods for determining CTs are called high-sensitive ones, and their main advantage is a very low minimum detectable concentration (limit of detection) (average 1 - 10 ng/L or less), which allows early detection of minor MC injury at the earliest stages of CVDs, and therefore they can change the understanding of disease development mechanisms and open up new diagnostic possibilities. One of the most common and dangerous early diseases of the cardiovascular system is hypertension (HT). The novelty of this article lies in the discussion of a new diagnostic direction - predicting the risk of developing CVDs and their dangerous complications in patients with HT by determining the concentration of CTs. In addition, pathophysiological mechanisms underlying MC injury and the release of CTs into the bloodstream and the elimination of CTs into the urine are proposed. This information will contribute to additional fundamental and clinical research to verify the new diagnostic possibility of using CTs in clinical practice (for the management of patients with HT).

A review of cardiac troponin I detection by surface enhanced Raman spectroscopy: Under the spotlight of point-of-care testing

Cardiac troponin I (cTnI) is a biomarker widely related to acute myocardial infarction (AMI), one of the leading causes of death around the world. Point-of-care testing (POCT) of cTnI not only demands a short turnaround time for its detection but the highest accuracy levels to set expeditious and adequate clinical decisions. The analytical technique Surface-enhanced Raman spectroscopy (SERS) possesses several properties that tailor to the POCT format, such as its flexibility to couple with rapid assay platforms like microfluidics and paper-based immunoassays. Here, we analyze the strategies used for the detection of cTnI by SERS considering POCT requirements. From the detection ranges reported in the reviewed literature, we suggest the diseases other than AMI that could be diagnosed with this technique. For this, a section with information about cardiac and non-cardiac diseases with cTnI release, including their release kinetics or cut-off values are presented. Likewise, POCT features, the use of SERS as a POCT technique, and the biochemistry of cTnI are discussed. The information provided in this review allowed the identification of strengths and lacks of the available SERS-based point-of-care tests for cTnI and the disclosing of requirements for future assays design.

The Role of Fine Particles (PM 2.5) in the Genesis of Atherosclerosis and Myocardial Damage: Emphasis on Clinical and Epidemiological Data, and Pathophysiological Mechanisms

Due to the fact that atherosclerotic cardiovascular diseases (CVDs) dominate in the structure of morbidity, disability and mortality of the population, the study of the risk factors for the development of atherosclerotic CVDs, as well as the study of the underlying pathogenetic mechanisms thereof, is the most important area of scientific research in modern medicine. Understanding these aspects will allow to improve the set of treatment and preventive measures and activities. One of the important risk factors for the development of atherosclerosis, which has been actively studied recently, is air pollution with fine particulate matter (PM 2.5). According to clinical and epidemiological data, the level of air pollution with PM 2.5 exceeds the normative indicators in most regions of the world and is associated with subclinical markers of atherosclerosis and mortality from atherosclerotic CVDs. The aim of this article is to systematize and discuss in detail the role of PM 2.5 in the development of atherosclerosis and myocardial damage.

The relationship between pulmonary artery obstruction index and troponin in thorax computed tomography in pulmonary embolism

Aim: To study the relation between troponin and pulmonary artery obstruction index in thoracic computerized tomography in patients diagnosed with acute pulmonary embolism. Material and Method: Data obtained from patients hospitalized in the ward and intensive care units with a pulmonary embolism diagnosis between January 2016 and February 2022 were scanned retrospectively. The full blood count, D-dimer, C-reactive protein, procalcitonin, troponin I, thoracic computerized tomography (CT), angiography, and bilateral lower extremity venous Doppler ultrasonography data were extracted. Patients with left heart failure, renal failure, gastrointestinal hemorrhage, sepsis, respiratory system disease, burns, ischemic stroke, or subarachnoid hemorrhage were excluded. The obstruction indices were calculated according to storage defects in the main, right, left, lobar, and segmental pulmonary artery branches in CT angiography. Results: While 57.0% of the 69 patients included in the study were female, 42.1% were male. The obstruction index in the high troponin-I group was significantly higher than that in the normal troponin-I group (p=0.006). In addition, the obstruction index was significantly higher in patients with bilateral pulmonary embolism than in those with unilateral pulmonary embolism (

On the Effect of Heterophilic Antibodies on Serum Levels of Cardiac Troponins: A Brief Descriptive Review

Serum levels of cardiac troponins can be increased both with myocardial damage and in the absence of myocardial damage. In the second case, this is due to the influence of false-positive factors, among which heterophilic antibodies play a significant role. Understanding the causes of the formation of heterophilic antibodies, the features and mechanisms of their effect on serum levels of cardiac troponins, is an important condition for interpreting a false-positive result due to the influence of heterophilic antibodies. This brief, descriptive review presents the causes of heterophilic-antibodies formation and discusses their effect on serum levels of cardiac troponins.

Bidirectional Relationship Between Cancer and Heart Failure: Insights on Circulating Biomarkers

Cancer and heart failure are the two leading causes of death in developed countries. These two apparently distinct clinical entities share similar risk factors, symptoms, and pathophysiological mechanisms (inflammation, metabolic disturbances, neuro-hormonal and immune system activation, and endothelial dysfunction). Beyond the well-known cardiotoxic effects of oncological therapies, cancer and heart failure are thought to be tied by a bidirectional relationship, where one disease favors the other and vice versa. In this context, biomarkers represent a simple, reproducible, sensitive and cost-effective method to explore such relationship. In this review, we recapitulate the evidence on cardiovascular and oncological biomarkers in the field of cardioncology, focusing on their role in treatment-naïve cancer patients. Cardioncological biomarkers are useful tools in risk stratification, early detection of cardiotoxicity, follow-up, and prognostic assessment. Intriguingly, these biomarkers might contribute to better understand the common pathophysiology of cancer and heart failure, thus allowing the implementation of preventive and treatment strategies in cardioncological patients

Porcine Circovirus type 2 infected myocardial tissue transcriptome signature

The goal of this study was to compare the global gene expression profile in cardiac tissues of pig infected with porcine circovirus 2 (PCV2) to that of healthy cells. Since PCV2 infection causes severe cardiovascular lesions, the myocardial tissue model was chosen for this study. In High-throughput transcriptome analysis, DESeq2 and CLC genomics workbench analyses revealed a total of 196 significantly differentially expressed genes (DEGs) (p-value < 0.05). Furthermore, 194 transcripts were upregulated, while only two were downregulated (HSPA6 and DNAJA1), with fold changes ranging from 16.293 to -10.002. Among the KEGG canonical pathways targeted by the DEGs in the functional analysis, adrenergic signalling in cardiomyocytes, Cardiac Muscle Contraction, Hypertrophic Cardiomyopathy (HCM), and Dilated Cardiomyopathy (DCM) tends to be enriched. The differentially expressed highly connected (DEHC) biomarker genes in pathogenicity of PCV2 infection, such as LDB3, MYOZ2, CASQ2, TNNT2, MLC2V, MYBPC3, ACTC1, TCAP, TNNI3, TRDN, CSRP3, MYL3, RYR2, LMOD2, MYH7, etc., were identified using protein-protein interaction (PPI) network analysis. The study might provide detailed information on the dysregulated genes and biological pathways in infected myocardial tissues that may be essential for PCV2-related heart pathology.

Metabolic Pathway of Cardiospecific Troponins: From Fundamental Aspects to Diagnostic Role (Comprehensive Review)

Many molecules of the human body perform key regulatory functions and are widely used as targets for the development of therapeutic drugs or as specific diagnostic markers. These molecules undergo a significant metabolic pathway, during which they are influenced by a number of factors (biological characteristics, hormones, enzymes, etc.) that can affect molecular metabolism and, as a consequence, the serum concentration or activity of these molecules. Among the most important molecules in the field of cardiology are the molecules of cardiospecific troponins (Tns), which regulate the processes of myocardial contraction/relaxation and are used as markers for the early diagnosis of ischemic necrosis of cardiomyocytes (CMC) in myocardial infarction (MI). The diagnostic value and diagnostic capabilities of cardiospecific Tns have changed significantly after the advent of new (highly sensitive (HS)) detection methods. Thus, early diagnostic algorithms of MI were approved for clinical practice, thanks to which the possibility of rapid diagnosis and determination of optimal tactics for managing patients with MI was opened. Relatively recently, promising directions have also been opened for the use of cardiospecific Tns as prognostic markers both at the early stages of the development of cardiovascular diseases (CVD) (arterial hypertension (AH), heart failure (HF), coronary heart disease (CHD), etc.), and in non-ischemic extra-cardiac pathologies that can negatively affect CMC (for example, sepsis, chronic kidney disease (CKD), chronic obstructive pulmonary disease (COPD), etc.). Recent studies have also shown that cardiospecific Tns are present not only in blood serum, but also in other biological fluids (urine, oral fluid, pericardial fluid, amniotic fluid). Thus, cardiospecific Tns have additional diagnostic capabilities. However, the fundamental aspects of the metabolic pathway of cardiospecific Tns are definitively unknown, in particular, specific mechanisms of release of Tns from CMC in non-ischemic extra-cardiac pathologies, mechanisms of circulation and elimination of Tns from the human body, mechanisms of transport of Tns to other biological fluids and factors that may affect these processes have not been established. In this comprehensive manuscript, all stages of the metabolic pathway are consistently and in detail considered, starting from release from CMC and ending with excretion (removal) from the human body. In addition, the possible diagnostic role of individual stages and mechanisms, influencing factors is analyzed and directions for further research in this area are noted.

The Importance of Cardiac Troponin Metabolism in the Laboratory Diagnosis of Myocardial Infarction (Comprehensive Review)

The study of the metabolism of endogenous molecules is not only of great fundamental significance but also of high practical importance, since many molecules serve as drug targets and/or biomarkers for laboratory diagnostics of diseases. Thus, cardiac troponin molecules have long been used as the main biomarkers for confirmation of diagnosis of myocardial infarction, and with the introduction of high-sensitivity test methods, many of our ideas about metabolism of these cardiac markers have changed significantly. In clinical practice, there are opening new promising diagnostic capabilities of cardiac troponins, the understanding and justification of which are closely connected with the fundamental principles of the metabolism of these molecules. Our current knowledge about the metabolism of cardiac troponins is insufficient and extremely disconnected from various literary sources. Thus, many researchers do not sufficiently understand the potential importance of cardiac troponin metabolism in the laboratory diagnosis of myocardial infarction. The purpose of this comprehensive review is to systematize information about the metabolism of cardiac troponins and during the discussion to focus on the potential impact of cTns metabolism on the laboratory diagnosis of myocardial infarction. The format of this comprehensive review includes a sequential consideration and analysis of the stages of the metabolic pathway, starting from possible release mechanisms and ending with elimination mechanisms. This will allow doctors and researchers to understand the significant importance of cTns metabolism and its impact on the laboratory diagnosis of myocardial infarction.

Metabolites Concentration in Plasma and Heart Tissue in Relation to High Sensitive Cardiac Troponin T Level in Septic Shock Pigs

Elevated circulating cardiac troponin T (cTnT) is frequent in septic shock patients. Signs of myocardial ischemia and myocyte necrosis are not universally present, but the precise mechanism for elevated cTnT is unknown. We investigated plasma and heart tissue metabolites concentration in six septic shock (SS) and three sham swine undergoing a protocol of polymicrobial septic shock and resuscitation, in order to highlight possible pathways and biomarkers involved in troponin release (high sensitive cardiac troponin T, hs-cTnT). The animals were divided into two groups: the high cTnT group (n = 3) were pigs showing a significantly higher concentration of cTnT and lactate after resuscitation; the low cTnT group (n = 6, three sham and three septic shock) characterized by a lower value of cTnT and a lactate level < 2 mmol/L. Spearman correlation was assessed on plasma fold-change of cTnT, cytokines (TNF-α and IL-10), and metabolites. Finally, the fold-change between the end of resuscitation and baseline values (Res./BL) of plasma metabolites was used to perform a partial least square discriminant analysis (PLS-DA) with three latent variables. Before building the model, the number of features was reduced by summing up the metabolites of the same class that resulted similarly correlated to cTnT fold-change. Proline and glycine were significantly higher in the high cTnT group at the end of experiment both in the myocardium and plasma analyses. Moreover, plasma proline fold-change was found to be positively correlated with cTnT and cytokine fold-changes, and trans-4-hydroxyproline (t4-OH-Pro) fold-change was positively correlated with cTnT fold-change. The PLS-DA model was able to separate the two groups and, among the first ranked features based on VIP score, we found sugars, t4-OH-Pro, proline, creatinine, total amount of sphingomyelins, and glycine. Proline, t4-OH-Pro, and glycine are very abundant in collagen, and our results may suggest that collagen degradation could represent a possible mechanism contributing to septic myocardial injury. The common phenotype of septic cardiomyopathy could be associated to dysregulated collagen metabolism and/or degradation, further exacerbated by higher inflammation and oxidative stress.

Features of the Metabolisms of Cardiac Troponin Molecules-Part 1: The Main Stages of Metabolism, Release Stage

Cardiac troponins (cTns) have long been the most valuable and specific biomarkers for detecting ischemic myocardial cells (MCs) injury, which is one of the key signs of myocardial infarction (MI). Modern methods (highly sensitive and ultra-sensitive immunoassays (hs-cTns)) of detection are an important and indispensable tool for the early diagnosis of MI and the choice of patient management protocols. Timely diagnosis of MI can significantly improve the prognosis of patients. However, in real clinical practice, doctors often face a significant problem when using cTns-the difficulty of differential diagnosis due to frequent and unexplained increases in the concentration of cTns in blood serum. In addition, there is conflicting information that may potentially affect the diagnostic capabilities and value of cTns: the influence of certain biological factors (diurnal rhythm, gender and age) on serum cTns levels; extra-cardiac expression of cTns; the possibilities of non-invasive diagnosis of MI; and other pathological conditions that cause non-ischemic injury to MCs. To solve these problems, it is necessary to concentrate on studying the metabolism of cTns. The review of our current knowledge about cTns metabolism consists of two parts. In this (first) part of the manuscript, the main stages of cTns metabolism are briefly described and the mechanisms of cTns release from MCs are considered in detail.

Cardiac Troponins Metabolism: From Biochemical Mechanisms to Clinical Practice (Literature Review)

The metabolic processes of endo- and exogenous compounds play an important role in diagnosing and treating patients since many metabolites are laboratory biomarkers and/or targets for therapeutic agents. Cardiac troponins are one of the most critical biomarkers to diagnose cardiovascular diseases, including acute myocardial infarction. The study of troponin metabolism is of great interest as it opens up new possibilities for optimizing laboratory diagnostics. This article discusses in detail the key stages of the cardiac troponins metabolism, in particular the mechanisms of release from a healthy myocardium, mechanisms of circulation in the bloodstream, possible mechanisms of troponin penetration into other biological fluids (oral fluid, cerebrospinal fluid, pericardial and amniotic fluids), mechanisms of elimination of cardiac troponins from the blood, and daily changes in the levels of troponins in the blood. Considering these aspects of cardiac troponin metabolism, attention is focused on the potential value for clinical practice.