Implications of High Sensitivity Troponin Levels After Lung Transplantation.

Trends in high-sensitivity cardiac troponin I (hs-cTnI) after lung transplant (LT) and its clinical value are not well stablished. This study aimed to determine kinetics of hs-cTnI after LT, factors impacting hs-cTnI and clinical outcomes. LT recipients from 2015 to 2017 at Toronto General Hospital were included. Hs-cTnI levels were collected at 0-24 h, 24-48 h and 48-72 h after LT. The primary outcome was invasive mechanical ventilation (IMV) >3 days. 206 patients received a LT (median age 58, 35.4% women; 79.6% double LT). All patients but one fulfilled the criteria for postoperative myocardial infarction (median peak hs-cTnI = 4,820 ng/mL). Peak hs-cTnI correlated with right ventricular dysfunction, >1 red blood cell transfusions, bilateral LT, use of EVLP, kidney function at admission and time on CPB or VA-ECMO. IMV>3 days occurred in 91 (44.2%) patients, and peak hs-cTnI was higher in these patients (3,823 vs. 6,429 ng/mL, p < 0.001 after adjustment). Peak hs-cTnI was higher among patients with had atrial arrhythmias or died during admission. No patients underwent revascularization. In summary, peak hs-TnI is determined by recipient comorbidities and perioperative factors, and not by coronary artery disease. Hs-cTnI captures patients at higher risk for prolonged IMV, atrial arrhythmias and in-hospital death.

Risk stratification and prognosis prediction using cardiac biomarkers in COVID-19: a single-centre retrospective cohort study.

OBJECTIVE: There is a need for a robust tool to stratify the patient's risk with COVID-19. We assessed the prognostic values of cardiac biomarkers for COVID-19 patients. METHODS: This is a single-centre retrospective cohort study. Consecutive laboratory-confirmed COVID-19 patients admitted to the Kobe City Medical Center General Hospital from July 2020 to September 2021 were included. We obtained cardiac biomarker values from electronic health records and institutional blood banks. We stratified patients with cardiac biomarkers as high-sensitive troponin I (hsTnI), N-terminal pro-B-type natriuretic peptide (NT-proBNP), creatine kinase (CK) and CK myocardial band (CK-MB), using the clinically relevant thresholds. Prespecified primary outcome measure was all-cause death. RESULTS: A total of 917 patients were included. hsTnI, NT-proBNP, CK and CK-MB were associated with the significantly higher cumulative 30-day incidence of all-cause death (hsTnI: <5.0 ng/L group; 4.3%, 5.0 ng/L-99%ile upper reference limit (URL) group; 8.8% and ≥99% ile URL group; 25.2%, p<0.001. NT-proBNP: <125 pg/mL group; 5.3%, 125-900 pg/mL group; 10.5% and ≥900 pg/mL group; 31.9%, p<0.001. CK:

Pathogenic TNNI1 variants disrupt sarcomere contractility resulting in hypo- and hypercontractile muscle disease.

Troponin I (TnI) regulates thin filament activation and muscle contraction. Two isoforms, TnI-fast (TNNI2) and TnI-slow (TNNI1), are predominantly expressed in fast- and slow-twitch myofibers, respectively. TNNI2 variants are a rare cause of arthrogryposis, whereas TNNI1 variants have not been conclusively established to cause skeletal myopathy. We identified recessive loss-of-function TNNI1 variants as well as dominant gain-of-function TNNI1 variants as a cause of muscle disease, each with distinct physiological consequences and disease mechanisms. We identified three families with biallelic TNNI1 variants (F1: p.R14H/c.190-9G>A, F2 and F3: homozygous p.R14C), resulting in loss of function, manifesting with early-onset progressive muscle weakness and rod formation on histology. We also identified two families with a dominantly acting heterozygous TNNI1 variant (F4: p.R174Q and F5: p.K176del), resulting in gain of function, manifesting with muscle cramping, myalgias, and rod formation in F5. In zebrafish, TnI proteins with either of the missense variants (p.R14H; p.R174Q) incorporated into thin filaments. Molecular dynamics simulations suggested that the loss-of-function p.R14H variant decouples TnI from TnC, which was supported by functional studies showing a reduced force response of sarcomeres to submaximal [Ca2+] in patient myofibers. This contractile deficit could be reversed by a slow skeletal muscle troponin activator. In contrast, patient myofibers with the gain-of-function p.R174Q variant showed an increased force to submaximal [Ca2+], which was reversed by the small-molecule drug mavacamten. Our findings demonstrated that TNNI1 variants can cause muscle disease with variant-specific pathomechanisms, manifesting as either a hypo- or a hypercontractile phenotype, suggesting rational therapeutic strategies for each mechanism.

Dapagliflozin prevents ERK activation and SGLT2-dependent endoglin upregulation in a mechanically provoked cardiac injury model.

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are rapidly gaining ground in the treatment of heart failure (HF) with reduced ejection fraction (HFrEF) and acute myocardial infarction (AMI) by an unknown mechanism. Upregulation of Na+/H+ exchanger 1 (NHE1), SGLT1, and Ca2+/calmodulin-dependent protein kinase II (CaMKII) in the diseased hearts was found to be attenuated by prolonged SGLT2i treatment. Unfortunately, dapagliflozin is not well understood as to how Na+/Ca2+ homeostasis is affected in cardiomyocytes. In this study, we aimed to investigate whether mechanical stretch in cardiomyocytes upregulate SGLT2, resulted to loss of Na+/Ca2+ homeostasis via ERK and eNOS signaling. AMI (+) and AMI (-) serum levels were estimated using ELISA assays of TGFß-1 or endoglin (CD105). Human cardiomyocyte cell line AC16 was subjected to different stresses: 5% mild and 25% aggressive, at 1 Hz for 24 h. Immunofluorescence assays were used to estimate troponin I, CD105, SGLT1/2, eNOSS633, and ERK1/2T202/Y204 levels was performed for 5% (mild), and 25% elongation for 24 h. AMI (+) serum showed increased TGFß1 and CD105 compared to AMI (-) patients. In consistent, troponin I, CD105, SGLT1/2, eNOSS633 and ERK1/2T202/Y204 were upregulated after 25% of 24 h cyclic stretch. Dapagliflozin addition caused SGLT2 inhibition, which significantly decreased troponin I, CD105, SGLT1/2, eNOSS633, and ERK1/2T202/Y204 under 25% cyclic stretching. In summary, SGLT2 may have sensed mechanical stretch in a way similar to cardiac overloading as in vivo. By blocking SGLT2 in stretched cardiomyocytes, the AMI biomarkers (CD105, troponin I and P-ERK) were decreased, potentially to rescue eNOS production to maintain normal cellular function. This discovery of CD105 and SGLT2 increase in mechanically stretched cardiomyocytes suggests that SGLT2 may conceive a novel role in direct or indirect sensing of mechanical stretch, prompting the possibility of an in vitro cardiac overloaded cell model, an alternative to animal heart model.

Automatic ultrasensitive lateral flow immunoassay based on a color-enhanced signal amplification strategy.

Lateral flow immunoassays (LFIAs) are an essential and widely used point-of-care test for medical diagnoses. However, commercial LFIAs still have low sensitivity and specificity. Therefore, we developed an automatic ultrasensitive dual-color enhanced LFIA (DCE-LFIA) by applying an enzyme-induced tyramide signal amplification method to a double-antibody sandwich LFIA for antigen detection. The DCE-LFIA first specifically captured horseradish peroxidase (HRP)-labeled colored microspheres at the Test line, and then deposited a large amount of tyramide-modified signals under the catalytic action of HRP to achieve the color superposition. A limit of detection (LOD) of 3.9 pg/mL and a naked-eye cut-off limit of 7.8 pg/mL were achieved for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleoprotein. Additionally, in the inactivated virus detections, LOD equivalent to chemiluminescence (0.018 TCID50/mL) was obtained, and it had excellent specificity under the interference of other respiratory viruses. High sensitivity has also been achieved for detection of influenza A, influenza B, cardiac troponin I, and human chorionic gonadotrophin using this DCE-LFIA, suggesting the assay is universally applicable. To ensure the convenience and stability in practical applications, we created an automatic device. It provides a new practical option for point-of-care test immunoassays, especially ultra trace detection and at-home testing.

[Risk factors for acute respiratory distress syndrome in patients with traumatic hemorrhagic shock].

OBJECTIVE: To investigate the risk factors of acute respiratory distress syndrome (ARDS) after traumatic hemorrhagic shock. METHODS: This was a retrospective cohort study of 314 patients with traumatic hemorrhagic shock at Trauma Medicine Center, Peking University People's Hospital from December 2012 to August 2021, including 152 male patients and 162 female patients, with a median age of 63.00 (49.75-82.00) years. The demographic data, past medical history, injury assessment, vital signs, laboratory examination and other indicators of these patients during hospitalization were recorded. These patients were divided into two groups, ARDS group (n=89) and non-ARDS group (n=225) according to whether there was ARDS within 7 d of admission. Risk factors for ARDS were identified using Logistic regression. The C-statistic expressed as a percentage [area under curve (AUC) of the receiver operating characteristic (ROC) curve] was used to assess the discrimination of the model. RESULTS: The incidence of ARDS after traumatic hemorrhagic shock was 28.34%. Finally, Logistic regression model showed that the independent risk factors of ARDS after traumatic hemorrhagic shock included male, history of coronary heart disease, high acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score, road traffic accident and elevated troponin Ⅰ. The OR and 95% confidence intervals (CI) were 4.01 (95%CI: 1.75-9.20), 5.22 (95%CI: 1.29-21.08), 1.07 (95%CI: 1.02-1.57), 2.53 (95%CI: 1.21-5.28), and 1.26 (95%CI: 1.02-1.57), respectively; the P values were 0.001, 0.020, 0.009, 0.014, and 0.034, respectively. The ROC curve was used to analyze the value of each risk factor in predicting ARDS. It was found that the AUC for predicting ARDS after traumatic hemorrhagic shock was 0.59 (95%CI: 0.51-0.68) for male, 0.55 (95%CI: 0.46-0.64) for history of coronary heart disease, 0.65 (95%CI: 0.57-0.73) for APACHE Ⅱ score, 0.58 (95%CI: 0.50-0.67) for road traffic accident, and 0.73 (95%CI: 0.66-0.80) for elevated troponin Ⅰ, with an overall predictive value of 0.81 (95%CI: 0.74-0.88). CONCLUSION: The incidence of ARDS in patients with traumatic hemorrhagic shock is high, and male, history of coronary heart disease, high APACHE Ⅱ score, road traffic accident and elevated troponin Ⅰ are independent risk factors for ARDS after traumatic hemorrhagic shock. Timely monitoring these indicators is conducive to early detection and treatment of ARDS after traumatic hemorrhagic shock.

In suspected ACS, hs-cTnI- vs. c-cTnI-guided care was associated with improved outcomes at 5 y in certain subgroups.

SOURCE CITATION: Lee KK, Doudesis D, Ferry AV, et al; High-STEACS Investigators. Implementation of a high sensitivity cardiac troponin I assay and risk of myocardial infarction or death at five years: observational analysis of a stepped wedge, cluster randomised controlled trial. BMJ. 2023;383:e075009. 38011922.

Troponin efficacy in the diagnosis of acute coronary syndrome in patients with chronic renal failure.

There is no consensus on whether cardiac troponins with high reliability values should be different diagnostic criteria for acute myocardial infarction in patients with and without renal dysfunction. Although it is often emphasized that the etiology of elevated troponin levels in chronic kidney disease (CKD) remains unclear, elevated cardiac troponin (cTnT) levels have been associated with increased subclinical cardiac damage in these patient groups. In this study, we investigated the value of cTnT value in diagnosing acute coronary syndrome in CKD patients with high clinical suspicion of acute coronary syndrome and without acute ST segment elevation on electrocardiogram. The aim was to prevent cardiac ischemia from being overlooked in CKD patients. Coronary angiography revealed vessel occlusion in 192 patients, and the mortality rate after treatment decisions was 6.7%. The first measured troponin results showed a significant difference in patients who did not survive, indicating the prognostic value of troponin levels. Troponin values were compared with cardiovascular pathologies obtained by angiography, and elevated troponin levels strongly correlated with pathologic angiography results. The conclusion highlighted that despite prognostic uncertainties, biomarkers used for acute myocardial infarction diagnosis in patients with renal insufficiency are reliable in those with renal dysfunction. Elevated cTnT levels in CKD patients are considered a clear marker of cardiac ischemia, emphasizing the need for careful consideration of troponin values in this population.

l-Cysteine-Tuned the Hierarchical Structure Based on Benzimidazole: Synthesis, Characterization, and Application in Ratiometric Electrochemiluminescence Immunoassay.

Efficient and robust electrochemiluminescence (ECL) emitters are crucial for enhancing the ECL immunosensor sensitivity. This study introduces a novel ECL emitter, CoBIM/Cys, featuring a hierarchical core-shell structure. The core of the structure is created through the swift coordination between the sulfhydryl and carboxyl groups of l-cysteine (l-Cys) and cobalt ions (Co2+), while the shell is constructed by sequentially coordinating benzimidazole (BIM) with Co2+. This design yields a greater specific surface area and a more intricate porous structure compared to CoBIM, markedly enhancing mass transfer and luminophore accessibility. Moreover, the l-Cys and Co2+ core introduces Co-S and Co-O catalytic sites, which improve the catalytic decomposition of H2O2, leading to an increased production of hydroperoxyl radicals (OOH•). This mechanism substantially amplifies the ECL performance. Leveraging the competitive interaction between isoluminol and BIM for OOH• during ECL emission, we developed a ratiometric immunosensor for cardiac troponin I (cTnI) detection. This immunosensor demonstrates a remarkably broad detection range (1 pg mL-1 to 10 ng mL-1), a low detection limit (0.4 pg mL-1), and exceptional reproducibility and specificity.

Cardiac troponin I as predictor for cardiac and other mortality in the German randomized lung cancer screening trial (LUSI).

Cardiac Troponin I (cTnI) could be used to identify individuals at elevated risk of cardiac death in lung cancer (LC) screening settings. In a population-based, randomized LC screening trial in Germany ("LUSI" study) serum cTnI was measured by high-sensitivity assay in blood samples collected at baseline, and categorized into unquantifiable/low (< 6 ng/L), intermediate (≥ 6-15 ng/L), and elevated (≥ 16 ng/L). Cox proportional-hazard models were used to estimate risk of all-cause and cardiac mortality with cTnI levels. After exclusion criteria, 3653 participants were included for our analyses, of which 82.4% had low, 12.8% intermediate and 4.8% elevated cTnI, respectively. Over a median follow up of 11.87 years a total of 439 deaths occurred, including 67 caused by cardiac events. Within the first 5 years after cTnI measurement, intermediate or elevated cTnI levels showed approximately 1.7 (HR = 1.69 [95% CI 0.57-5.02) and 4.7-fold (HR = 4.66 [1.73-12.50]) increases in risk of cardiac death relative to individuals with unquantifiable/low cTnI, independently of age, sex, smoking and other risk factors. Within this time interval, a risk model based on age, sex, BMI, smoking history and cTnI showed a combined area under the ROC curve (AUC) of 73.6 (58.1-87.3), as compared to 70.4 (53.3-83.5) for a model without cTnI. Over the time interval of > 5-10 years after blood donation, the relative risk associations with cTnI and were weaker. cTnI showed no association with mortality from any other (non-cardiac) cause. Our findings show that cTnI may be of use for identifying individuals at elevated risk specifically of short-term cardiac mortality in the context of LC screening.

Rapid diagnosis of acute myocardial infarction through integrated microfluidic chips for detection of characteristic targets.

Myoglobin (Myo), creatine kinase-MB (CKMB), and cardiac troponin I (cTnI) are crucial biomarkers for diagnosing acute myocardial infarction (AMI) The accurate and rapid detection of these three targets can greatly improve the prognosis of AMI patients. Herein, this study developed a microfluidic immunofluorescence method that can detect all three targets in 10-15 min. Ultrasonic atomization and spray technology are used to modify the surface of the injection-molded microfluidic chip (MFC), which effectively solves the problem of biological cross-linking and antibody immobilization on the MFC surface. In addition, it improves the hydrophilicity of the chip surface, thus enhancing fluid self-driving effect. The linear response towards Myo, CKMB and cTnI range from 5 ng/mL to 500 ng/mL, 1 ng/mL to 70 ng/mL, and 0.05 ng/mL to 30 ng/mL, respectively. The intra-batch precision is ≤ 10%, and the inter-batch precision is ≤ 15%. Furthermore, this method shows good consistency compared with the BECKMAN ACCESS2 chemiluminescent immunoanalyzer. The present work provides an AMI diagnostic method with high sensitivity, good repeatability, high accuracy and simple operation, which can satisfy the needs of clinical diagnosis, and shows promising application prospects.

Clinical relevance and advances in detection of translational biomarker cardiac troponin.

Cardiovascular diseases (CVD) are a range of diseases, pointing the functional hindrances in the heart and blood vessels of the human system that contributes to 48.6 % of the world's adult death rate. The diagnosis of CVD relies upon the Electro Cardio Gram (ECG) and detection of muscle markers such as troponins. Among the cardiac trio, Cardiac Troponin I (cTnI) weighing 23 KiloDalton (kDa) is a sorted biomarker for CVD. cTnI remains high in the blood after 1-2 weeks of myocardial damage. Testing of cTnI in CVD patients aids in diagnosis and risk stratification of the disease. Different determination systems including optical, electrochemical, and acoustic have been put forward for monitoring the cTnI which are Point of Care (POC) that promotes simple and sensitive detection of cTnI. The modern era has paved way to high-sensitivity Troponin I (hscTnI) devices that can detect up to 0.01 ng/ml in human blood/plasma/serum. Yet, the practice of hscTnI is impracticable due to cost inefficiency. Development of new hscTnI devices with minimal investment and maximal detection range will meet the global requirement. This review gives an over view on different detection systems of cardiac troponin I which stands as a translational detection molecule for CVDs.

Peripheral blood indicators and COVID-19: an observational and bidirectional Mendelian randomization study.

Blood is critical for health, supporting key functions like immunity and oxygen transport. While studies have found links between common blood clinical indicators and COVID-19, they cannot provide causal inference due to residual confounding and reverse causality. To identify indicators affecting COVID-19, we analyzed clinical data (n = 2,293, aged 18-65 years) from Guangzhou Medical University's first affiliated hospital (2022-present), identifying 34 significant indicators differentiating COVID-19 patients from healthy controls. Utilizing bidirectional Mendelian randomization analyses, integrating data from over 2.46 million participants from various large-scale studies, we established causal links for six blood indicators with COVID-19 risk, five of which is consistent with our observational findings. Specifically, elevated Troponin I and Platelet Distribution Width levels are linked with increased COVID-19 susceptibility, whereas higher Hematocrit, Hemoglobin, and Neutrophil counts confer a protective effect. Reverse MR analysis confirmed four blood biomarkers influenced by COVID-19, aligning with our observational data for three of them. Notably, COVID-19 exhibited a positive causal relationship with Troponin I (Tnl) and Serum Amyloid Protein A, while a negative association was observed with Plateletcrit. These findings may help identify high-risk individuals and provide further direction on the management of COVID-19.

Impaired Relaxation in Induced Pluripotent Stem Cell-Derived Cardiomyocytes with Pathogenic TNNI3 Mutation of Pediatric Restrictive Cardiomyopathy.

BACKGROUND: Restrictive cardiomyopathy (RCM) is characterized by impaired diastolic function with preserved ventricular contraction. Several pathogenic variants in sarcomere genes, including TNNI3, are reported to cause Ca2+ hypersensitivity in cardiomyocytes in overexpression models; however, the pathophysiology of induced pluripotent stem cell (iPSC)-derived cardiomyocytes specific to a patient with RCM remains unknown. METHODS AND RESULTS: We established an iPSC line from a pediatric patient with RCM and a heterozygous TNNI3 missense variant, c.508C>T (p.Arg170Trp; R170W). We conducted genome editing via CRISPR/Cas9 technology to establish an isogenic correction line harboring wild type TNNI3 as well as a homozygous TNNI3-R170W. iPSCs were then differentiated to cardiomyocytes to compare their cellular physiological, structural, and transcriptomic features. Cardiomyocytes differentiated from heterozygous and homozygous TNNI3-R170W iPSC lines demonstrated impaired diastolic function in cell motion analyses as compared with that in cardiomyocytes derived from isogenic-corrected iPSCs and 3 independent healthy iPSC lines. The intracellular Ca2+ oscillation and immunocytochemistry of troponin I were not significantly affected in RCM-cardiomyocytes with either heterozygous or homozygous TNNI3-R170W. Electron microscopy showed that the myofibril and mitochondrial structures appeared to be unaffected. RNA sequencing revealed that pathways associated with cardiac muscle development and contraction, extracellular matrix-receptor interaction, and transforming growth factor-ß were altered in RCM-iPSC-derived cardiomyocytes. CONCLUSIONS: Patient-specific iPSC-derived cardiomyocytes could effectively represent the diastolic dysfunction of RCM. Myofibril structures including troponin I remained unaffected in the monolayer culture system, although gene expression profiles associated with cardiac muscle functions were altered.

Ternary BiOI/Bi2S3/Au Nanosheet Arrays as a Photoelectrochemical Signal Converter for the Detection of Cardiac Troponin I.

Nanosheet arrays with stable signal output have become promising photoactive materials for photoelectrochemical (PEC) immunosensors. However, an essential concern is the facile recombination of carriers in one-component nanoarrays, which cannot be readily prevented, ultimately resulting in weak photocurrent signals. In this study, an immunosensor using gold nanoparticle-anchored BiOI/Bi2S3 nanosheet arrays (BiOI/Bi2S3/Au) as a signal converter was fabricated for sensitive detection of cardiac troponin I (cTnI). The ternary nanosheet arrays were prepared by a simple method in which Bi2S3 was well-coated on the BiOI surface by in situ growth, whereas the addition of Au further improved the photoelectric conversion efficiency and could link more antibodies. The three-dimensional (3D) ordered sheet-like network array structure and BiOI/Bi2S3/Au ternary nanosheet arrays showed stable and high photoelectric signal output and no significant difference in signals across different batches under visible light excitation. The fabricated immunosensor has a sensitive response to the target detection marker cTnI in a wide linear range of 500 fg/mL to 50 ng/mL, and the detection limit was 32 fg/mL, demonstrating good stability and selectivity. This work not only shows the great application potential of ternary heterojunction arrays in the field of PEC immunosensors but also provides a useful exploration for improving the stability of immunosensors.

The Value of Combined Detection of Serum BNP, Cardiac Troponin-I and Dynamic Electrocardiogram in Early Clinical Diagnosis and Prognosis of Patients with Acute Myocardial Infarction.

BACKGROUND: Acute myocardial infarction (AMI) is a prevalent cardiovascular disease resulting from myocardial ischemia and necrosis due to coronary artery occlusion. AMI is characterized by a sudden onset and high mortality, underscoring the significance of early diagnosis and treatment for improving patient prognosis. This study endeavors to assess the utility of a combined assessment involving serum brain natriuretic peptide (BNP), cardiac troponin-I (cTnI), and dynamic electrocardiogram (ECG) in the early clinical diagnosis and prognosis prediction of AMI. METHODS: This paper constitutes a retrospective study. All enrolled patients underwent dynamic ECG examination. The study compared the serum levels of BNP and cTnI, along with pertinent dynamic ECG parameters [turbulence slope (TS) and standard deviation (SDNN) of the 24-hour interval between normal atrial depolarization and ventricular depolarization (R-R)], between the observation group (AMI patients) and the control group (patients with unstable angina (UA)). To evaluate the early diagnostic potential of AMI, we utilized receiver operating characteristic (ROC) curves to analyze serum BNP, cTnI, dynamic ECG, and their combined utility. Furthermore, a follow-up period of 6 months was conducted for AMI patients to record major adverse cardiovascular events (MACE). RESULTS: In the observation group, the serum levels of BNP and cTnI were significantly higher than those in the control group (p < 0.001), while dynamic ECG parameters, specifically TS and SDNN, were significantly lower in the observation group compared to the control group (p < 0.001). The results obtained from the ROC curve analysis revealed that the area under the curve (AUC) for BNP, cTnI, dynamic ECG, and their combination in early AMI diagnosis were 0.838, 0.887, 0.874, and 0.974, respectively. The 95% confidence intervals (CI) were 0.781~0.884, 0.836~0.926, 0.822~0.915, and 0.942~0.991, respectively. Sensitivity values were 64.29%, 82.14%, 91.07%, and 88.39%, and specificity values were 91.00%, 88.00%, 70.00%, and 98.00%, respectively. Significantly, the combination of all three markers demonstrated superior efficacy in early AMI diagnosis compared to any single index (p < 0.05). During the 6-month follow-up of 112 AMI patients, 22 experienced MACE. The MACE group exhibited notably higher serum BNP and cTnI levels compared to the non-MACE group. Additionally, dynamic electrocardiogram parameters TS and SDNN demonstrated a significant decrease (p < 0.05) in the MACE group. CONCLUSIONS: The combined assessment of serum BNP, cTnI, and dynamic electrocardiogram enhances the early clinical diagnostic potential for AMI and holds value in assessing the prognosis of AMI patients.

Troponin T is elevated in a relevant proportion of patients with 5q-associated spinal muscular atrophy.

Troponin T concentration (TNT) is commonly considered a marker of myocardial damage. However, elevated concentrations have been demonstrated in numerous neuromuscular disorders, pointing to the skeletal muscle as a possible extracardiac origin. The aim of this study was to determine disease-related changes of TNT in 5q-associated spinal muscular atrophy (SMA) and to screen for its biomarker potential in SMA. We therefore included 48 pediatric and 45 adult SMA patients in this retrospective cross-sequential observational study. Fluid muscle integrity and cardiac markers were analyzed in the serum of treatment-naïve patients and subsequently under disease-modifying therapies. We found a TNT elevation in 61% of SMA patients but no elevation of the cardiospecific isoform Troponin I (TNI). TNT elevation was more pronounced in children and particularly infants with aggressive phenotypes. In adults, TNT correlated to muscle destruction and decreased under therapy only in the subgroup with elevated TNT at baseline. In conclusion, TNT was elevated in a relevant proportion of patients with SMA with emphasis in infants and more aggressive phenotypes. Normal TNI levels support a likely extracardiac origin. Although its stand-alone biomarker potential seems to be limited, exploring TNT in SMA underlines the investigation of skeletal muscle integrity markers.

Diagnostic accuracy of baseline troponin and troponin change for the diagnosis of myocardial infarction complicated with heart failure.

BACKGROUND: The diagnosis of myocardial infarction (MI) in the presence of heart failure (HF) presents a clinical problem. While diagnostic algorithms using high-sensitivity cardiac troponin have been established for suspected MI, their accuracy in patients with HF remains uncertain. This study aims to assess the diagnostic accuracy of high-sensitivity troponin I (TnI) levels in identifying acute MI among patients with HF, focusing on baseline, absolute and relative TnI changes. METHODS: Data from 562 individuals admitted to the emergency department with suspected MI were retrospectively analysed. Two-point TnI and baseline brain natriuretic peptide (BNP) test results were available. HF status was determined based on clinical, laboratory and instrumental criteria. RESULTS: Among the 562 patients, 299 (53.2%) were confirmed having MI. Baseline TnI demonstrated predictive capability for MI in the overall population (area under the curve (AUC) 0.63), while TnI relative change exhibited superior performance (AUC 0.83). Baseline TnI accuracy varied significantly by group, notably decreasing in the third group (severe HF) (AUC 0.54) compared with the first and second groups (AUC 0.67 and AUC 0.71, respectively). TnI relative change demonstrated consistent accuracy across all groups, with AUCs of 0.79, 0.79 and 0.89 for the first, second and third groups, respectively, even after adjustment for age, sex and glomerular filtration rate. DISCUSSION: Troponin relative change is a reliable predictor of MI, even in patients with acute HF. Baseline TnI accuracy is influenced by HF severity. It is essential to consider HF status and BNP levels when employing high-sensitivity cardiac troponin testing to rule out suspected MIs.

Non-Canonical Localization of Cardiac Troponins: Expanding Functions or Causing Pathologies?

The troponin complex-consisting of three subunits: troponin C (TnC), cardiac troponin I (cTnI) and cardiac troponin T (cTnT)-plays a key role in the regulation of myocardial contraction. Troponins are preferentially localized in the cytoplasm and bind to myofibrils. However, numerous, albeit scattered, studies have shown the presence of troponins in the nuclei of muscle cells. There is increasing evidence that the nuclear localization of troponins may be functionally important, making troponins an important nuclear player in the pathogenesis of various diseases including cancer and myopathies. Further studies in this area could potentially lead to the development of treatments for certain pathologies. In this review, we collected and discussed recent data on the properties of non-canonically localized cardiac troponins, the molecular mechanisms leading to this non-canonical localization, and the possible functions or pathological effects of these non-canonically localized troponins.

Serial high sensitivity troponin sampling in patients with SARS-CoV-2 infection.

INTRODUCTION: Multiple studies have investigated the role of cardiac troponin (cTn) in the risk stratification of patients with COVID-19. Most of these investigations are based on cTn values at presentation and do not consider the prognostic significance of cTn changes over time. This study aimed to investigate the prognostic role of serial cTn measurements in patients hospitalized with COVID-19 with samples that were not obtained for clinical indications. METHODS: Patients hospitalized between April 2020 and March 2021 with PCR-confirmed SARS-CoV-2 infection were evaluated. Blood samples collected for any reason were stored for subsequent analysis. If clinical high sensitivity hs-cTnT (Roche) was not measured, samples were tested separately in batches. Hs-cTnI (Abbott) was also evaluated. RESULTS: There were 228 unique patients. There were 21 (9.2 %) deaths. No patient with a low hs-cTnT (<6 ng/L) died and 1 patient with low hs-cTnI (<5 ng/L) died. Myocardial injury was associated with higher odds of death, when defined by hs-cTnT (OR: 7.88, 95 % CI: 2.04-30.40, p = 0.003) or hs-cTnI (OR: 7.46, 95 % CI: 2.68-20.77, p < 0.001). This association remained after propensity weighting. An increasing pattern was associated with higher odds of death compared to a stable pattern for hs-cTnT (OR: 5.45, 95 % CI: 1.81-16.40, p = 0.003) and hs-cTnI (OR: 4.49, 95 % CI: 1.02-19.81, p = 0.048). Among patients with myocardial injury defined by hs-cTnT, an increasing pattern was associated with higher odds of death compared to a decreasing pattern (OR: 4.80, 95 % CI: 1.16-19.97, p = 0.031). CONCLUSIONS: Patients hospitalized with COVID-19 with myocardial injury have higher odds of death. Serial hs-cTn testing provides additional risk stratification in these patients.