Surface plasmon resonance biosensors for early troponin detection

Acute myocardial infarction (AMI) is one of the life-threatening causes that decrease blood flow to the heart, leading to increased mortality and related complications. Recently, the measure of blood concentration of cardiac biomarkers has been suggested to overcome the limitations of electrocardiography (ECG) analyses for early diagnosis of this disease. Troponins, especially cardiac troponin I and cardiac troponin T, with high sensitivity and specificity, are considered the gold standards in myocardial diagnosis. Recently, the use of new biosensors such as surface plasmon resonance (SPR) for early detection of these biomarkers has been greatly appreciated. Due to the rapid, sensitive, real-time, and label-free detection of SPR-based biosensors, they can be applied for selective and nonspecific absorption that is intended to be used as an in situ cardiac biosensor. Here, we exclusively discussed the updated developments of these valuable predictors for the possible occurrence of AMI detected by SPR.

Cas13b-mediated RNA targeted therapy alleviates genetic dilated cardiomyopathy in mice

BACKGROUND

Recent advances in gene editing technology have opened up new avenues for in vivo gene therapy, which holds great promise as a potential treatment method for dilated cardiomyopathy (DCM). The CRISPR-Cas13 system has been shown to be an effective tool for knocking down RNA expression in mammalian cells. PspCas13b, a type VI-B effector that can be packed into adeno-associated viruses and improve RNA knockdown efficiency, is a potential treatment for diseases characterized by abnormal gene expression.

RESULTS

Using PspCas13b, we were able to efficiently and specifically knockdown the mutant transcripts in the AC16 cell line carrying the heterozygous human TNNT2R141W (hTNNT2R141W) mutation. We used adeno-associated virus vector serotype 9 to deliver PspCas13b with specific single guide RNA into the hTNNT2R141W transgenic DCM mouse model, effectively knocking down hTNNT2R141W transcript expression. PspCas13b-mediated knockdown significantly increased myofilament sensitivity to Ca2+, improved cardiac function, and reduced myocardial fibrosis in hTNNT2R141W DCM mice.

CONCLUSIONS

These findings suggest that targeting genes through Cas13b is a promising approach for in vivo gene therapy for genetic diseases caused by aberrant gene expression. Our study provides further evidence of Cas13b's application in genetic disease therapy and paves the way for future applicability of genetic therapies for cardiomyopathy.

Association of longitudinal cardiac troponin trajectory with adverse events in patients with cardiac sarcoidosis

BACKGROUND

Although high-sensitivity cardiac troponins may be sensitive and easily repeatable markers of disease activity in patients with cardiac sarcoidosis (CS), the association between longitudinal cardiac troponin trajectory and adverse events remains unclear. This study aimed to clarify whether longitudinal cardiac troponin levels were associated with adverse events in patients with CS.

METHODS

We examined 63 consecutive CS-initiated prednisolone (PSL) patients with available longitudinal high-sensitivity cardiac troponin T (cTnT) data between December 2013 and March 2023. The area under the cTnT trajectory, which reflected cumulative cTnT release, was calculated to assess the association between longitudinal cTnT levels and adverse events. Patients were divided into two groups according to the median area under the cTnT trajectory per month. The primary outcome was a composite of sustained ventricular tachycardia or fibrillation, worsening heart failure, and sudden cardiac death (SCD).

RESULTS

In total, 463 cTnT measurements were collected over a median follow-up period of 30.4 (interquartile range [IQR] 15.6-34.2) months. The primary outcome was observed in 12 (19%) patients. A higher area under the cTnT trajectory was significantly associated with an increased incidence of the primary outcome (P = 0.027), while cTnT levels before and one month after initiation of PSL, and these changes were not related to adverse events (P = 0.179, 0.096, and 0.95, respectively).

CONCLUSIONS

Longitudinal cTnT trajectory following PSL initiation was associated with adverse cardiac events in patients with CS, suggesting that longitudinal measurement of cTnT would be useful for the early identification of high-risk patients.

Cardiac Troponin T and NT-proBNP for Prediction of 30-Day Readmission or Death in Patients with Acute Dyspnea: Data from the Akershus Cardiac Examination 2 Study

INTRODUCTION

N-terminal pro-B-type natriuretic peptide (NT-proBNP) and cardiac troponin T (cTnT) measurements are recommended in patients with acute dyspnea. We aimed to assess the prognostic merit of cTnT compared to NT-proBNP for 30-day readmission or death in patients hospitalized with acute dyspnea.

METHODS

We measured cTnT and NT-proBNP within 24 h in 314 patients hospitalized with acute dyspnea and adjudicated the cause of the index admission. Time to first event of readmission or death ≤30 days after hospital discharge was recorded, and cTnT and NT-proBNP measurements were compared head-to-head.

RESULTS

Patients who died (12/314) or were readmitted (71/314) within 30 days had higher cTnT concentrations (median: 32.6, Q1-Q3: 18.4-74.2 ng/L vs. median: 19.4, Q1-Q3: 8.4-36.1 ng/L; p for comparison <0.001) and NT-proBNP concentrations (median: 1,753.6, Q1-Q3: 464.2-6,862.0 ng/L vs. median 984, Q1-Q3 201-3,600 ng/L; for comparison p = 0.027) compared to patients who survived and were not readmitted. cTnT concentrations were associated with readmission or death within 30 days after discharge both in the total cohort (adjusted hazard ratio [aHR]: 1.64, 95% confidence interval [CI]: 1.30-2.05) and in patients with heart failure (HF) (aHR: 1.58, 95% CI: 1.14-2.18). In contrast, NT-proBNP concentrations were not associated with short-term events, neither in the total cohort (aHR: 1.10, 95% CI: 0.94-1.30) nor in patients with adjudicated HF (aHR: 1.06, 95% CI: 0.80-1.40).

CONCLUSION

cTnT concentrations are associated with 30-day readmission or death in patients hospitalized with acute dyspnea, as well as in patients adjudicated HF.

Significance of raw DPV and CV data for chemometric discrimination

Electrochemical immunosensors coupled with reverse iontophoresis (RI) for noninvasive determination of cardiac troponins were developed and validated according to ICH Q2 (R1) guideline. Linearity was in 0.01-10 and 100-500 ng/mL ranges. LODs (ng/mL) were in 6-25 × 10-4, while LOQs (μg/mL) were in 18-7.5 × 10-4 range. Chemometric evaluation was performed on raw data simply by principle component analysis and cluster analysis to discriminate stages of immunosensors. This is the first demonstration of RI determination of cardiac troponins so far. Findings of the current manuscript have great potential to develop point of care diagnostic systems for major cardiac events, where high sensitivity and specificity are required.

Smartphone-based colorimetric detection of cardiac troponin T via label-free aptasensing

We report an aptasensing platform for the detection of cardiac troponin T (cTnT) in the immediate and early phases of acute myocardial infarction (AMI). High-flow filter paper was used to fabricate a microfluidic paper-based analytical device (μ-PAD), which was further modified with gold-decorated polystyrene microparticles functionalized with a highly specific cTnT aptamer. Herein, cTnT detection is presented in two linear ranges (0.01-0.8 μg/ml and 6.25-50 μg/ml) with an LoD of 3.9X10^-4 μg/ml, which is in agreement with reference values determined by the American Heart Association. The proposed platform showed remarkable selectivity against AMI-associated cardiac biomarkers such as TNF-alpha, interleukin-6, cardiac troponin I, and reactive protein-C. This aptasensor is a label-free assay that relies only on smartphone-based image analysis and takes less processing time in comparison with traditional methods like ELISA. Furthermore, it exhibits outstanding stability over 23 days when devices are stored at 4 °C. The reported platform is a stable and cost-effective method for the on-site and user-friendly detection of cTnT in normal saline buffer and diluted human serum.

The bidirectional association of C-peptide with cardiovascular risk in nondiabetic adults and patients with newly diagnosed type 2 diabetes mellitus: a retrospective cohort study

Background

Recent literature reported the biological role of C-peptide, but this role is still controversial and unclear. The primary aim of this study was to investigate associations between C-peptide and cardiovascular biomarkers as well as events.

Methods

A total of 55636 participants who had a health examination from 2017 to 2021 were included. Of them, 6727 participants visited the hospital at least twice. Cardiovascular biomarkers like high-sensitivity C-reactive protein (hs-CRP) and high-sensitivity cardiac troponin T (hs-cTnT) were measured and their relationships with fasting C-peptide were evaluated for all participants. Cardiovascular events were obtained during the last visit and their associations with C-peptide were evaluated for those participants who visited the hospital at least twice.

Results

Among the included participants, 11.1% had a previous type 2 diabetes mellitus (T2DM). In the participants without previous T2DM, the relationships between fasting C-peptide and hs-CRP and hs-cTnT were negative if the value of fasting C-peptide was < 1.4 ng/mL and positive if the value was ≥ 1.4 ng/mL. These relationships remained significant after adjusting for hemoglobin A1c, insulin resistance index, and its interaction with C-peptide, even if the participants were stratified by glucose metabolism status or levels of insulin resistance index. Hazard ratios of cardiovascular events were first decreased and then increased with the increasing of baseline C-peptide levels, though these associations became unsignificant using the multivariate Cox regression model. Unlike the participants without previous T2DM, the associations of C-peptide with cardiovascular biomarkers and events were not significant in the patients with previous T2DM.

Conclusions

The associations of C-peptide with cardiovascular biomarkers and events were different between the participants without previous T2DM and those with previous T2DM. The effect of C-peptide on cardiovascular risk may be bidirectional, play a benefit role at a low level, and play a harmful role at a high level in the nondiabetic adults and the patients with newly diagnosed T2DM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01636-z.

Cardiovascular biomarkers in pregnancy with diabetes and associations to glucose control

AIM

Cardiovascular disease (CVD) is a leading cause of death in both men and women. Type 1 and 2 diabetes mellitus (DM1 and DM2) are well-known risk factors for CVD. In addition, gestational diabetes mellitus (GDM) is a female sex-specific risk factor for CVD. Here, we measure circulating concentrations of cardiac troponin T (cTNT), N-terminal pro-B-type natriuretic peptide (NT-proBNP) and growth differentiation factor 15 (GDF-15) during pregnancy-a window of time often referred to as a cardiovascular stress test for women.

METHODS

This study utilized data from 384 pregnant women: 64 with DM1, 16 with DM2, 35 with GDM and 269 euglycemic controls. Blood was predominantly sampled within a week before delivery. Cardiovascular biomarker concentrations were measured in serum using electrochemiluminescence immunoassay.

RESULT

Circulating cTnT levels were higher in women with DM1, DM2 and GDM as compared to controls, whereas NT-proBNP and GDF-15 levels were only increased in women with DM1. Glucose dysregulation, assessed by third trimester HbA1c levels, positively correlated with all three CVD biomarker levels, whereas pregestational body mass index correlated negatively with GDF-15.

CONCLUSIONS

Our results support the presence of myocardial affection in women with diabetic disorders during pregnancy. Although pregestational DM1 in this study was associated with the most adverse CVD biomarker profile, women with GDM displayed an adverse cTnT profile similar to what we found in women with pregestational DM2. This supports that women with GDM should be offered long-term intensified cardiovascular follow-up and lifestyle advice following delivery, similarly to the well-established CV follow-up of women with pregestational DM.

Cardiac troponin T and autoimmunity in skeletal muscle aging

Age-related muscle mass and strength decline (sarcopenia) impairs the performance of daily living activities and can lead to mobility disability/limitation in older adults. Biological pathways in muscle that lead to mobility problems have not been fully elucidated. Immunoglobulin G (IgG) infiltration in muscle is a known marker of increased fiber membrane permeability and damage vulnerability, but whether this translates to impaired function is unknown. Here, we report that IgG1 and IgG4 are abundantly present in the skeletal muscle (vastus lateralis) of ~ 50% (11 out of 23) of older adults (&gt; 65 years) examined. Skeletal muscle IgG1 was inversely correlated with physical performance (400 m walk time: r = 0.74, p = 0.005; SPPB score: r =  - 0.73, p = 0.006) and muscle strength (r =  - 0.6, p = 0.05). In a murine model, IgG was found to be higher in both muscle and blood of older, versus younger, C57BL/6 mice. Older mice with a higher level of muscle IgG had lower motor activity. IgG in mouse muscle co-localized with cardiac troponin T (cTnT) and markers of complement activation and apoptosis/necroptosis. Skeletal muscle-inducible cTnT knockin mice also showed elevated IgG in muscle and an accelerated muscle degeneration and motor activity decline with age. Most importantly, anti-cTnT autoantibodies were detected in the blood of cTnT knockin mice, old mice, and older humans. Our findings suggest a novel cTnT-mediated autoimmune response may be an indicator of sarcopenia.

Retrospective Analysis of Autologous Stem Cell Transplantation for AL Amyloidosis: A Study from the Multiple Myeloma Working Group of the Japan Society for Hematopoietic Cell Transplantation

Autologous stem cell transplantation (ASCT) is the standard of care for eligible patients with light-chain (AL) amyloidosis, but little is known about it in Asian populations. To investigate the outcome of and prognostic factors for ASCT, we retrospectively analyzed ASCT cases registered to the Transplant Registry Unified Management Program between December 1999 and December 2015, with extra clinical information collected through a secondary survey. The primary endpoint was overall survival (OS). Hematologic response, organ response, and transplantation-related mortality were analyzed as secondary endpoints. The database search identified 330 patients (median age, 57 years; range, 31 to 74), and the secondary survey provided details for the 110 patients (33.3%) included in the study cohort. Fewer than 3 organs were involved in 56.4% of the patients, with cardiac involvement in 57.3%. Performance status (PS) was 0 to 1 in 83.6%. The conditioning melphalan dose was reduced in 54.6%. Overall hematologic response was a partial response or better in 77.6% of the patients and a complete response in 49.3%. The 5-year OS was 70.1%. A PS of 0 to 1 was associated with a significantly better prognosis in terms of OS. Although survival after ASCT for AL amyloidosis improved over time, poor PS and cardiac involvement had negative impacts on prognosis. The early mortality after ASCT was 6.4%. Poor PS and cardiac involvement led to high early mortality. A brain natriuretic peptide (BNP) level of 400 pg/mL was associated with worse OS. Our study has several limitations inherent to a retrospective analysis using a questionnaire. The depth of response and biomarker responses were significantly limited by the degree of missing data. Nonetheless, our data support the importance of careful patient selection for good outcomes of ASCT in patients with AL amyloidosis. In our cohort, poor PS and cardiac involvement had a negative impact on prognosis, and BNP level was a useful prognostic factor.

Prognostic value of subclinical myocardial necrosis using high-sensitivity cardiac troponin T in patients with prediabetes

BACKGROUND

Risk stratification of patients with prediabetes is an unmet clinical need. Here, we examine the utility of subclinical myocardial necrosis assessed by high-sensitivity cardiac troponin T (hs-cTnT) in predicting health outcomes in stable subjects with prediabetes.

METHODS

hs-cTnT was analyzed by a high-sensitivity assay (Roche 5th generation) in 2631 stable subjects with prediabetes (HbA1c 5.7-6.4% or fasting glucose 100-125 mg/dL without previous diagnosis of diabetes or glucose-lowering therapy) who underwent elective coronary angiography for cardiac evaluation, and followed for major adverse cardiac events (MACE; death, myocardial infarction, stroke) over 3 years and all-cause mortality over 5 years.

RESULTS

In our study cohort, hs-cTnT was highly prevalent with a median level of 13 ng/L (interquartile range 8.2-21.6 ng/L). Hs-cTnT was independently associated with incident MACE at 3 years (Q4 vs. Q1 adjusted hazard ratio (HR) 2.42 [95% CI 1.69-3.46], P < 0.001) and 5-year mortality (adjusted HR 3.8 [95% CI 2.55-5.67], P < 0.001). This association remained significant in all subsets after adjustment for traditional risk factors and multiple factors known to increase hs-cTnT levels. Moreover, hs-cTnT independently predicted event risk in primary prevention subjects (n = 557, HR 5.46 [95% CI 1.50-19.89), p < 0.01) for MACE; HR 9.53 [95% CI 2.08-43.73] for all-cause mortality) and secondary prevention subjects (n = 2074, HR 1.86 [95% CI 1.31-2.66], P < 0.001 for MACE; and 2.7 [95% CI 1.79-4.08), P < 0.001 for all-cause mortality).

CONCLUSIONS

In stable prediabetic subjects, the presence of subclinical myocardial necrosis as detected by hs-cTnT portends heightened long-term adverse cardiovascular event risk. Hs-cTnT levels may help to stratify risk and improve clinical decision making in patients with prediabetes. Trial registration ClinicalTrials.gov Identifier: NCT00590200.

Changes in S100B and troponin levels in a fetal sheep model of worsening acidosis

BACKGROUND

S100B and cardiac troponin T (c-TnT) are relevant biomarkers at birth of hypoxic-ischemic encephalopathy (HIE) and myocardial ischemia secondary to metabolic acidosis during labor, respectively. The purpose was to assess in-utero changes in S100B and c-TnT levels in an experimental model of labor-like acidosis.

METHODS

Repeated umbilical cord occlusions (UCOs) in ten experiments were performed in mild (phase A, 1 UCO/5 mn), moderate (phase B, 1 UCO/3 mn), and severe (phase C, 1 UCO/2 mn) period. The experiments were stopped if arterial pH reached 6.90.

RESULTS

UCOs resulted in fetal acidosis with pH dropping to 6.99 ±0.13. When compared to the baseline period fetal S100B increased between phases A and B (7% ± 4 vs 17% ± 13, p = 0.030) and between phases A and C (7% ± 4 vs 24% ± 8, p < 0.001). Fetal c-TnT serum levels increased during occlusions: 102 ng/L (58-119) in phase A, vs 119 ng/L (103-198) in phase B vs 169 ng / L (128-268) in phase C (p < 0.05, for all). When compared to the baseline control period, fetal ΔcTnT was significantly modified throughout UCO series: 5.0% (-3; 45) in phase A, 51% (4; 263) in phase B, and 77% (56.5; 269) in phase C (p < 0.05 for all).

CONCLUSIONS

S100B and c-TnT increased when fetal acidosis occurred, which reflects the potential neurological damage and fetal cardiovascular adaptation.

Cardiac Troponin T: The Impact of Posttranslational Modifications on Analytical Immunoreactivity in Blood up to the Excretion in Urine

Cardiac troponin T (cTnT) is a sensitive and specific biomarker for detecting cardiac muscle injury. Its concentration in blood can be significantly elevated outside the normal reference range under several pathophysiological conditions. The classical analytical method in routine clinical analysis to detect cTnT in serum or plasma is a single commercial immunoassay, which is designed to quantify the intact cTnT molecule. The targeted epitopes are located in the central region of the cTnT molecule. However, in blood cTnT exists in different biomolecular complexes and proteoforms: bound (to cardiac troponin subunits or to immunoglobulins) or unbound (as intact protein or as proteolytic proteoforms). While proteolysis is a principal posttranslational modification (PTM), other confirmed PTMs of the proteoforms include N-terminal initiator methionine removal, N-acetylation, O-phosphorylation, O-(N-acetyl)-glucosaminylation, N(ɛ)-(carboxymethyl)lysine modification and citrullination. The immunoassay probably detects several of those cTnT biomolecular complexes and proteoforms, as long as they have the centrally targeted epitopes in common. While analytical cTnT immunoreactivity has been studied predominantly in blood, it can also be detected in urine, although it is unclear in which proteoform cTnT immunoreactivity is present in urine. This review presents an overview of the current knowledge on the pathophysiological lifecycle of cTnT. It provides insight into the impact of PTMs, not only on the analytical immunoreactivity, but also on the excretion of cTnT in urine as one of the waste routes in that lifecycle. Accordingly, and after isolating the proteoforms from urine of patients suffering from proteinuria and acute myocardial infarction, the structures of some possible cTnT proteoforms are reconstructed using mass spectrometry and presented.

Transthoracic echocardiography and cardiac biomarkers in healthy captive male and female squirrel monkeys (Saimiri spp.)

Background

Echocardiography is the most frequently used non -invasive diagnostic tool to evaluate cardiac anatomy and function in domestic species but increasingly also in non -domestic species, especially since cardiac disease is being recognized as an important cause of death in captive primates. The purpose of this cross -sectional study was to investigate the feasibility of transthoracic echocardiography in healthy squirrel monkeys as well as to provide species specific normal values for standard echocardiographic measurements. A secondary aim was to determine plasma and serum levels of the cardiac biomarkers, N -terminal pro -brain natriuretic peptide (NT -proBNP) and cardiac troponin T (cTnT). Furthermore, a commercial, non -invasive, smartphone -based ECG (AliveCor Vet TM) monitoring device was used to evaluate the heart rate and rhythm and to diagnose possible arrhythmias.

Results

In this study, transthoracic echocardiography of 14 squirrel monkeys was performed in right and left lateral recumbency. Similar standard right parasternal and left apical images were obtained as in dogs and cats and normal values for routine two -dimensional, time motion mode and Doppler mode measurements were generated. Thirteen animals were considered healthy and one squirrel monkey was identified with significant aortic dilation and regurgitation and consequently values obtained from this animal were not used when species specific normal values were calculated. NT -ProBNP and cTnT concentrations were available for 7 of the 13 healthy monkeys with NT -proBNP concentrations below detection limit in all animals and a mean cTnT concentration of 0.049 ng/mL. Electrocardiography was performed in all squirrel monkeys. The mean heart rate was 172 bpm. Frequent supraventricular premature beats were diagnosed in the squirrel monkey suffering from significant aortic dilation and regurgitation.

Conclusion

This study presents echocardiographic normal values and additional cardiovascular data in anaesthetised Saimiri monkeys, fundamental from both the perspective of zoo animal health care as well as scientific research, since the squirrel monkey is often used as an animal model for human disease.

A retrospective analysis of treatment outcomes in 45 patients with cardiac light-chain amyloidosis: a single-center experience in Japan

The prognosis of cardiac light-chain (AL) amyloidosis is considered to be very poor. We studied the treatment efficacy and outcomes by retrospectively analyzing the clinical results of 45 patients with cardiac AL amyloidosis treated at our hospital between September 2008 and March 2016. The group of patients analyzed included 29 males and 16 females with a median age of 68 years. Their baseline median NT-proBNP, cTnT, and dFLC were 3167 pg/ml, 0.080 ng/ml, and 286.17 mg/l, respectively. Twenty-eight patients were in Cardiac Stage (CS) III and 17 patients were in Revised Prognostic Stage (RPS) IV. At the median follow-up of 10 months, the median overall survival (OS) was 16 months and 3-year OS was 35.9%. The patients in CS III showed significantly poorer survival rate than those in CS I or II (3-year OS: 12.2% vs. 65.8%, p = 0.0115) and the patients in RPS IV showed significantly poorer survival rate than those in RPS I, II, or III (3-year OS: 11.0% vs. 53.3%, p = 0.000914). Regardless of the therapeutic approaches, patients who achieved hematological CR or cardiac organ response demonstrated significantly improved prognosis. Therefore, achievement of hematological and organ responses is important in the treatment of cardiac AL amyloidosis.

Establishing a new human hypertrophic cardiomyopathy-specific model using human embryonic stem cells

Symptom of ventricular hypertrophy caused by cardiac troponin T (TNNT2) mutations is mild, while patients often showed high incidence of sudden cardiac death. The 92nd arginine to glutamine mutation (R92Q) of cTnT was one of the mutant hotspots in hypertrophic cardiomyopathy (HCM). However, there are no such human disease models yet. To solve this problem, we generated TNNT2 R92Q mutant hESC cell lines (heterozygote or homozygote) using TALEN mediated homologous recombination in this study. After directed cardiac differentiation, we found a relative larger cell size in both heterozygous and homozygous TNNT2 R92Q hESC-cardiomyocytes. Expression of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and sarcoplasmic reticulum Ca²⁺-ATPase2a (SERCA2a) were downregulated, while myocyte specific enhancer factor 2c (MEF2c) and the ratio of beta myosin to alpha myosin heavy chain (MYH7/MYH6) were increased in heterozygous TNNT2 R92Q hESC-cardiomyocytes. TNNT2 R92Q mutant cardiomyocytes exhibited efficient responses to heart-related pharmaceutical agents. We also found TNNT2 R92Q heterozygous mutant cardiomyocytes showed increased calcium sensitivity and contractility. Further, engineered heart tissues (EHTs) prepared by combining rat decellularized heart extracellular matrices with heterozygous R92Q mutant cardiomyocytes showed similar drug responses as to HCM patients and increased sensitivity to caspofungin-induced cardiotoxicity. Using RNA-sequencing of TNNT2 R92Q heterozygous mutant cardiomyocytes, we found dysregulation of calcium might participated in the early development of hypertrophy. Our hESC-derived TNNT2 R92Q mutant cardiomyocytes and EHTs are good in vitro human disease models for future disease studies and drug screening.

The 99th percentile upper reference limit for the 5th generation cardiac troponin T assay in the United States

BACKGROUND

Determining diagnostic thresholds for cardiac troponin assays is key to interpreting their clinical performance. We describe the calculation of 99th percentile upper reference limits (URLs) for the Elecsys® Troponin T Gen 5 (TnT Gen 5) assay.

METHODS

Plasma and serum samples from healthy US participants were prospectively evaluated using TnT Gen 5 Short Turn Around Time and 18-min assays on cobas e 411 and cobas e 601 analyzers (Roche Diagnostics); with, up to 8 TnT Gen 5 results per participant.

RESULTS

A total of 10,402 TnT Gen 5 results from 1301 participants were included (50.4% female). Across 9 calculation methods, overall 99th percentile URL was 19.2 ng/l (females, 13.5-13.6 ng/l; males, 21.4-22.2 ng/l). Across different sample/assay/analyzer combinations, overall 99th percentile URLs ranged from 18.4-20.2 ng/l. Median TnT Gen 5 results increased with age, were higher in males, and ranged from 3.0-3.7 ng/l across races/ethnicities and from 3.0-3.6 ng/l across body mass index (BMI) classes. Applying additional exclusion criteria (N-terminal pro-brain natriuretic peptide, BMI and estimated glomerular filtration rate) resulted in lower 99th percentile URLs (overall, 16.9 ng/l; females, 11.8 ng/l; males, 18.5 ng/l).

CONCLUSION

Our findings facilitate the interpretation of TnT Gen 5 results in US clinical practice.

Pre- and post-race serum cardiac troponin T concentrations in Standardbred racehorses

Elevated cardiac troponin T (cTnT) concentrations may provide evidence of myocardial injury but physiological post-exercise release also occurs. Reference intervals are not fully established in horses making interpretation difficult. The aims of this study were to establish an upper reference limit for serum cTnT, compare pre-and post-race serum cTnT concentrations, and to evaluate factors that may influence these in a population of healthy, race-fit Standardbred racehorses. Serum samples were collected pre- (n = 108) and 1-2 h post-racing (n = 101) and analysed using a high sensitivity-cTnT assay. Reference limits with 90% confidence intervals (CI) were calculated by non-parametric methods using the bootstrap method. Effects of sex, age, racing speed, distance, placings and track surface were assessed by fitting generalized linear models with an identity link function and inverse Gaussian distribution. The upper reference limit for serum cTnT concentration was 27.4 ng/L (90% CI 13.1-32.0). The median serum cTnT concentration was significantly higher 1-2 h post-racing compared to pre-racing (P < 0.001). Age and sex did not significantly affect serum cTnT concentrations pre-racing (P = 0.5 and P = 0.11). Cardiac troponin T concentrations were significantly higher post-racing in females (P = 0.018). Racing speed and placings had no effect on serum cTnT concentrations post-race (P = 0.71 and P = 0.66). The study contributed towards establishing an upper reference limit for serum cTnT concentrations in a population of race-fit Standardbreds and evaluated factors that may have influenced the results obtained.

Prognostic Value of Cardiac Troponin I and T on Admission in Mortality of Multiple Trauma Patients Admitted to the Emergency Department: a Prospective Follow-up Study

Introduction:

The relationship between increased levels of cardiac troponins and morbidity and mortality of traumatic patients is not still well recognized.

Aim:

The aim of this study was to investigate the prognostic value of cardiac troponin I and T on admission in mortality of multiple trauma patients admitted to the emergency department.

Methods:

In this prospective follow-up study, the cardiac troponin I and T levels were measured in patients with multiple trauma referring to the emergency department (ED) between March 2014 and February 2015 at Imam Khomeini Hospital, Sari, Iran. Patients were followed prospectively until discharge from hospital or death.

Results:

The levels of cardiac troponins I and T in patients with multiple trauma were significantly associated with their mortality, especially at the level of 0.5 and 1.2 μg/dl (p<0.05). Multivariate regression analysis showed association of level of cardiac troponin I and T with patients’ mortality, after controlling for patients’ age, vital signs and GCS on admission. The sensitivity and specificity of troponin I at levels greater than 0.4 μg/dl in predict mortality in this study were as 65.5% and 55.3%, while the values for troponin T were 65.1% and 54.9%, respectively.

Conclusion:

Elevated cardiac troponin I and T levels provide excellent prognostic information regarding mortality in patients with multiple-trauma, independent of age, hemodynamic variables and GCS score.

Clinical Significance of Increased Cardiac Troponin T in Patients with Chronic Hemodialysis and Cardiovascular Disease: Comparison to B-Type Natriuretic Peptide and A-Type Natriuretic Peptide Increase

BACKGROUND

An increased cardiac troponin T (cTnT) level identifies a high-risk group in patients with end-stage renal disease; however, the mechanism of cTnT elevation remains unclear in such patients without acute coronary syndrome (ACS). Therefore, we explored the relationship between cTnT levels and the hemodynamic parameters and the prognostic potential of cTnT in stable patients with chronic hemodialysis (HD).

METHODS

We included consecutive 174 patients with HD who were referred for coronary angiography due to stable coronary artery disease (CAD), peripheral artery disease (PAD), or heart failure (HF). Hemodynamic measurement was performed, and plasma cTnT, B-type natriuretic peptide (BNP), and A-type natriuretic peptide (ANP) were measured at the same time. The potential of 3 biomarkers to predict all-cause mortality, cardiac death or hospitalized HF, and vascular event was assessed.

RESULTS

Increased log cTnT levels were correlated with increased log BNP and log ANP levels (r = 0.531, p < 0.001 and r = 0.411, p < 0.001, respectively). Not increased log cTnT, but increased log BNP and log ANP were associated with the presence of CAD and the extent of CAD. In contrast, they were all associated with the New York Heart Association functional classification and the presence of PAD and significantly correlated with left ventricular end-diastolic pressure (LVEDP) in an independent manner. Increased cTnT and BNP levels were associated with the mortality and hospitalized HF. However, increased cTnT was not associated with vascular events, unlike increased BNP.

CONCLUSIONS

In patients with chronic HD without ACS, increased cTnT reflected increased LVEDP and the presence of HF or PAD independently, and it did not reflect the presence of CAD in contrast to increased BNP. cTnT and BNP were significant prognostic predictors; however, increased cTnT was associated with HF-related events, not with arteriosclerotic events.

Diagnostic and prognostic utility of cardiac troponin in post-cardiac arrest care

BACKGROUND

Cardiac troponin is routinely tested in the post-cardiac arrest setting, but its utility in identifying ischaemic aetiology and predicting left ventricular systolic dysfunction (LVSD) and survival is not known.

METHODS

In a retrospective single center registry, we identified 145 consecutive patients who had achieved return of spontaneous circulation after cardiac arrest and had undergone serial cardiac troponin T (cTnT) testing, echocardiogram, and expert adjudication of aetiology. Initial and peak cTnT were evaluated for assessing ischaemic aetiology, LVSD, and survival to discharge using area under the receiver operating characteristic curve (AUROC).

RESULTS

Mean age was 61 ± 14 years and 71% were men. Of the 145 arrests, 19% had an ischaemic aetiology, 68% had LVSD post-arrest, and 55% survived to discharge. All patients had a positive initial cTnT at 0.01 ng/mL (clinical cut-off). Even at higher cut-offs of 10×, 100× and 1000×, initial cTnT performed poorly (AUROC 0.57, 0.56, and 0.56) and peak cTnT performed modestly (AUROC 0.55, 0.61, and 0.62) as diagnostic tests for ischaemic aetiology. Similarly, even at higher cut-offs, initial (AUROC 0.60, 0.62, 0.55) and peak (AUROC 0.57, 0.61, and 0.62) cTnT performed poorly to modestly at predicting LVSD. The test performed poorly for predicting survival to discharge (AUROC for all <0.6).

CONCLUSIONS

At both current and several-fold higher thresholds, cTnT does not perform sufficiently well to guide clinical decision-making or predict patient outcomes. Routine post-cardiac arrest testing of cTnT should be reevaluated.

Cardiac biomarkers but not measures of vascular atherosclerosis predict mortality in patients with peripheral artery disease

BACKGROUND

Peripheral artery disease (PAD) becomes more prevalent with advancing age and is associated with elevated risk of cardiovascular events and shortened life expectancy. We investigated the prognostic performance of cardiac and vascular biomarkers in a cohort of PAD patients.

METHODS

A total of 95 PAD patients were enrolled (mean age 68 years, range 47 to 86 years, 73 males). Carotid intima-media thickness (cIMT), ankle brachial index (ABI), high sensitive cardiac troponin T, and N-terminal pro-B-type Natriuretic Peptide (NT-proBNP) were measured.

RESULTS

During a median follow-up time of 9.5 years, 44 patients died and 51 patients survived. Upon Kaplan-Meier survival analysis hs-TnT (P < .001) or NT-proBNP levels (P < .001) above the median but not cIMT above the median (P = .488) or ABI below the median (P < .436)were associated with reduced survival rate. Upon univariate cox regression and after adjustment for age, gender, prior cerebral artery disease, and diabetes mellitus only the association between hs-cTnT and mortality remained significant (HR 1.93, 95% CI 1.33-2.79, P < .001). In receiver operating curve analysis hs-cTnT (area under the curve [AUC]: 0.77, 95% CI: 0.67-0.87, P < .001) NT-proBNP (AUC: 0.74, 95% CI: 0.64-0.84, P < .001) as well as hs-cTnT, and NT-proBNP combined (AUC: 0.79, 95% CI: 0.69-0.88, P < .001) were superior to cIMT (AUC: 0.64, 95%, CI: 0.53-0.76, P = .022) and ABI (AUC: 0.57, 95% CI: 0.44-0.68, P = .313) in discriminating risk for mortality.

CONCLUSION

hs-cTnT and NT-proBNP should be taken into account for prognosis of patients with PAD.

The cTnT response to acute exercise at the onset of an endurance training program: evidence of exercise preconditioning?

PURPOSE

Exercise induces a cardioprotective effect referred to as "preconditioning". Whether the preconditioning impacts upon the cardiac troponin T (cTnT) response to subsequent exercise bouts is unclear. This study investigated the effects of an initial exercise bout, a second exercise bout 48 h later, as well as subsequent exercise every 48 h for 4 days or a single identical exercise bout after 8 days of inactivity gap on cTnT response to acute exercise.

METHODS

Twenty-eight sedentary overweight young women were randomly assigned to either six bouts of exercise each separated by 48 h or three bouts of exercise with 48 h between the first two bouts and 8 days between the second and third bouts. All exercise bouts were identical (60% [Formula: see text], 200 kJ) and the total testing period (10 days) was the same for both groups. cTnT was assessed before and after the 1st, 2nd, and final exercise bouts.

RESULTS

cTnT increased (129%, P < 0.05) after the first bout of exercise in both groups (peak post-exercise cTnT, median [range], ng l^-1: 3.43[< 3.00-27.26]) with no between-group differences in the response. The second exercise bout had no significant (P > 0.05) effect on post-exercise cTnT (< 3.00[< 3.00-21.96]). The final exercise bout resulted in an increase (190%, P < 0.05) in cTnT (4.35[< 3.00-13.05]) in both groups.

CONCLUSIONS

A single bout exercise resulted in a temporary blunting of cTnT response to acute exercise 48 h later. The effect of exercise preconditioning was not preserved, regardless of whether followed by repeated exercise every 48 h or a cessation of exercise for 8 days.

Tegafur deteriorates established cardiovascular atherosclerosis in colon cancer: A case report and review of the literature

BACKGROUND

Cardiac toxic effect of tegafur (S-1) is extremely rare, and there has been no report on this issue so far.

CASE SUMMARY

We herein report a typical case of single S-1 administration after radical operation for colon cancer. The patient had no background or medical history of acute coronary syndrome (ACS), and only aortic and coronary atherosclerosis was revealed by computed tomography (CT) before surgery. He complained of sternum pain during the fifth cycle of S-1 treatment. Electrocardiogram (ECG) and serum cardiac marker cardiac troponin T (cTnT) strongly suggested ACS, which was possibly caused by S-1 cardiotoxicity.

CONCLUSION

Monitoring protocols based on ECG, CT, and cTnT should be performed in real time to evaluate cardiac function during S-1 administration.

Cardiac Troponin T in Healthy Full-Term Infants

In this prospective cohort study of healthy full-term infants, we hypothesized that high-sensitivity cardiac troponin T (hs-cTnT) would be elevated in cord blood, compared with adult reference values, and that it would further increase over the first days of age. Cardiac troponin T has been shown to be significantly increased in healthy full-term newborns compared with adult reference values, but there is no established reference range. Most studies of cTnT in newborns have been performed before the introduction of high-sensitivity cTnT (hs-cTnT) assay. We conducted a study including 158 full-term newborns, at Stockholm South General Hospital. High-sensitivity cTnT was analyzed in umbilical cord blood and at 2-5 days of age. Median hs-cTnT (interquartile range) in cord blood was 34(26-44) ng/L; 99th percentile 88 ng/L. Median hs-cTnT at 2-5 days of age was 92(54-158) ng/L; 99th percentile 664 ng/L. We conclude that hs-cTnT is elevated in cord blood in healthy, full-term newborn infants compared with adult reference values, and that it increases significantly during the first days of life. Our findings further underline the need of caution when using hs-cTnT as a measurement of cardiac impact in newborns.

Progressive Elevation of NT-ProBNP During Chemotherapy Is Related to Asymptomatic Cardiovascular Events in Patients With Multiple Myeloma

BACKGROUND

Patients with multiple myeloma (MM) are at risk of cardiovascular events (CVEs) as a result of disease burden- and treatment-related risk factors. Cardiac biomarkers have been reported to be more sensitive than left ventricular ejection fraction in detecting CVEs. We sought to explore CVEs risk factors in MM patients and to establish sensitive predictors of biomarkers.

PATIENTS AND METHODS

We studied 116 newly diagnosed MM patients who received chemotherapy in our department. Echocardiograms were examined at baseline and after 4 cycles of treatment, as well as upon clinical suspicion of a cardiac event or after an adjustment of treatment regimens. Cardiac biomarkers, including troponin T, myohemoglobin, and N terminal pro B-type natriuretic peptide (NT-proBNP), were estimated before each cycle and within 24 hours after chemotherapy, which was provided for at least 4 cycles.

RESULTS

Thirteen patients (11.2%) experienced CVEs, seven of which were subclinical. There was no significant difference between the CVE group and the non-CVE group in terms of general patient characteristics, MM disease factors, or chemotherapy drugs. The baseline levels of left ventricular ejection fraction and NT-proBNP were comparable between the 2 groups. NT-proBNP levels increased rapidly after chemotherapy and fell to normal levels before administration of the next cycle in all patients (60 pg/mL vs. 446 pg/mL, P < .001). Patients with asymptomatic CVEs showed a significantly higher proportion of progressively elevated NT-proBNP compared to symptomatic CVE and non-CVE patients (57% vs. 0 vs. 6.1%, P = .035).

CONCLUSION

The dynamic change in NT-proBNP may predict early asymptomatic cardiac damage and allow interventional strategies to avoid cardiac decompensation.

Sex-Related Aspects of Biomarkers in Cardiac Disease

Biomarkers play an important role in the clinical management of cardiac care. In particular, cardiac troponins (cTn) and natriuretic peptides are the cornerstones for the diagnosis of acute myocardial infarction (AMI) and for the diagnosis of heart failure (HF), respectively. Current guidelines do not make a distinction between women and men. However, the commonly used "one size fits all" algorithms are topic of debate to improve assessment of prognosis, particularly in women. Due to the high-sensitivity assays (hs-cTn), lower cTn levels (and 99th percentile upper reference limits) were observed in women as compared with men. Sex-specific diagnostic thresholds may improve the diagnosis of AMI in women, though clinical relevance remains controversial and more trials are needed. Also other diagnostic aspects are under investigation, like combined biomarkers approach and rapid measurement strategies. For the natriuretic peptides, previous studies observed higher concentrations in women than in men, especially in premenopausal women who might benefit from the cardioprotective actions. Contrary to hs-cTn, natriuretic peptides are particularly incorporated in the ruling-out algorithms for the diagnosis of HF and not ruling-in. Clinical relevance of sex differences here seems marginal, as clinical research has shown that negative predictive values for ruling-out HF were hardly effected when applying a universal diagnostic threshold that is independent from sex or other risk factors. Apart from the diagnostic issues of AMI in women, we believe that in the future most sex-specific benefits of cardiac biomarkers can be obtained in patient follow-up (guiding therapy) and prognostic applications, fitting modern ideas on preventive and personalized medicine.

Cardiac troponin T and fast skeletal muscle denervation in ageing

BACKGROUND

Ageing skeletal muscle undergoes chronic denervation, and the neuromuscular junction (NMJ), the key structure that connects motor neuron nerves with muscle cells, shows increased defects with ageing. Previous studies in various species have shown that with ageing, type II fast-twitch skeletal muscle fibres show more atrophy and NMJ deterioration than type I slow-twitch fibres. However, how this process is regulated is largely unknown. A better understanding of the mechanisms regulating skeletal muscle fibre-type specific denervation at the NMJ could be critical to identifying novel treatments for sarcopenia. Cardiac troponin T (cTnT), the heart muscle-specific isoform of TnT, is a key component of the mechanisms of muscle contraction. It is expressed in skeletal muscle during early development, after acute sciatic nerve denervation, in various neuromuscular diseases and possibly in ageing muscle. Yet the subcellular localization and function of cTnT in skeletal muscle is largely unknown.

METHODS

Studies were carried out on isolated skeletal muscles from mice, vervet monkeys, and humans. Immunoblotting, immunoprecipitation, and mass spectrometry were used to analyse protein expression, real-time reverse transcription polymerase chain reaction was used to measure gene expression, immunofluorescence staining was performed for subcellular distribution assay of proteins, and electromyographic recording was used to analyse neurotransmission at the NMJ.

RESULTS

Levels of cTnT expression in skeletal muscle increased with ageing in mice. In addition, cTnT was highly enriched at the NMJ region-but mainly in the fast-twitch, not the slow-twitch, muscle of old mice. We further found that the protein kinase A (PKA) RIα subunit was largely removed from, while PKA RIIα and RIIβ are enriched at, the NMJ-again, preferentially in fast-twitch but not slow-twitch muscle in old mice. Knocking down cTnT in fast skeletal muscle of old mice: (i) increased PKA RIα and reduced PKA RIIα at the NMJ; (ii) decreased the levels of gene expression of muscle denervation markers; and (iii) enhanced neurotransmission efficiency at NMJ.

CONCLUSIONS

Cardiac troponin T at the NMJ region contributes to NMJ functional decline with ageing mainly in the fast-twitch skeletal muscle through interfering with PKA signalling. This knowledge could inform useful targets for prevention and therapy of age-related decline in muscle function.

Cardiac troponin T as a predictor of cardiac death in patients with left ventricular dysfunction

Background

Cardiac troponin T (cTnT) has been reported to be associated with cardiac mortality.

In the present study, we evaluated the role of routine assessment of cTnT as a predictor of future cardiac death in patients with left ventricular (LV) dysfunction.

Methods

Patients who were eligible for prophylactic implantable cardioverter defibrillator (ICD) were included from cardiac catheterization database. Inclusion criteria were patients with LV ejection fraction of ≤ 35% and with New York Heart Association (NYHA) ≥class II. Exclusion criteria were patients with acute coronary syndrome, ICD for secondary prevention, NYHA class IV, and lack of data. The final study patients were divided into the following three groups in accordance with two quartile points of serum cTnT levels: low cTnT, intermediate cTnT, and high cTnT groups. The primary endpoint of this study was cardiac death.

Results

A total of 70 patients were included (mean age, 62±13 years; male individuals, 56; ischemic, 36; and non-ischemic, 34). During the observation period of 2.2 years, cardiac death was observed in 17 patients (fatal arrhythmic event, 9; heart failure, 7; myocardial infarction, 1). In the Kaplan–Meier analysis, the high cTnT group showed the highest risk among all the groups (p<0.001). Even in sub-analyses for ischemic and non-ischemic patients, the results were the same, and the high cTnT group showed the highest event rate (p<0.05). In contrast, no cardiac death was observed in the low cTnT group.

Conclusion

The cTnT levels in a stable state were associated with cardiac death in patients with LV dysfunction, even in those with non-ischemic diseases.

Increased constitutive nitric oxide production by whole body periodic acceleration ameliorates alterations in cardiomyocytes associated with utrophin/dystrophin deficiency

Duchenne Muscular Dystrophy (DMD) cardiomyopathy is a progressive lethal disease caused by the lack of the dystrophin protein in the heart. The most widely used animal model of DMD is the dystrophin-deficient mdx mouse; however, these mice exhibit a mild dystrophic phenotype with heart failure only late in life. In contrast, mice deficient for both dystrophin and utrophin (mdx/utrn^-/-, or dKO) can be used to model severe DMD cardiomyopathy where pathophysiological indicators of heart failure are detectable by 8-10weeks of age. Nitric oxide (NO) is an important signaling molecule involved in vital functions of regulating rhythm, contractility, and microcirculation of the heart, and constitutive NO production affects the function of proteins involved in excitation-contraction coupling. In this study, we explored the efficacy of enhancing NO production as a therapeutic strategy for treating DMD cardiomyopathy using the dKO mouse model of DMD. Specifically, NO production was induced via whole body periodic acceleration (pGz), a novel non-pharmacologic intervention which enhances NO synthase (NOS) activity through sinusoidal motion of the body in a headward-footward direction, introducing pulsatile shear stress to the vascular endothelium and cardiomyocyte plasma membrane. Male dKO mice were randomized at 8weeks of age to receive daily pGz (480cpm, Gz±3.0m/s², 1h/d) for 4weeks or no treatment, and a separate age-matched group of WT animals (pGz-treated and untreated) served as non-diseased controls. At the conclusion of the protocol, cardiomyocytes from untreated dKO animals had, respectively, 4.3-fold and 3.5-fold higher diastolic resting concentration of Ca²⁺ ([Ca²⁺]_d) and Na⁺ ([Na⁺]_d) compared to WT, while pGz treatment significantly reduced these levels. For dKO cardiomyocytes, pGz treatment also improved the depressed contractile function, decreased oxidative stress, blunted the elevation in calpain activity, and mitigated the abnormal increase in [Ca²⁺]_d upon mechanical stress. These improvements culminated in a significant reduction in circulating cardiac troponin T (cTnT) and an extension of the median lifespan of dKO mice from 16 to 31weeks. Treatment with L-NAME (NOS inhibitor) significantly decreased overall lifespan and abolished the cardioprotective properties elicited by pGz. Our results provide evidence that enhancement of NO synthesis by pGz can ameliorate cellular dysfunction in dKO cardiomyocytes and may represent a novel therapeutic intervention in DMD cardiomyopathy patients.

Acute effect of intermittent and continuous aerobic exercise on release of cardiac troponin T in sedentary men

BACKGROUND

Studies have shown that acute exercise can increase serum concentrations of cardiac biomarkers, including cardiac troponin T (cTnT). We investigated the acute effects of intermittent (IE) and continuous (CE) exercise at the same cardiac workload on myocardial necrosis biomarkers in sedentary men.

METHODS

Eleven sedentary healthy men aged 22.3±1.9years completed the study. The subjects were divided into two groups and performed, in random order, IE (intensity alternating between 50% (2min) and 80% (1min) HRreserve) or CE (60% HRreserve). The study was designed as a single-blinded randomised crossover trial performed on two distinct experimental days separated by a 1-week washout period. Each session consisted of 40min of aerobic exercise, either IE or CE, on a treadmill. Blood samples were taken before (PRE), immediately after (POST) and 1h after (POST-1) each exercise session.

RESULTS

hs-cTnT significantly increased immediately after exercise in both protocols and remained elevated at POST-1 (P<0.05). There was no significant difference between POST and POST-1 values(P>0.05). Neither CE nor IE caused any significant change in CK-MB (P>0.05). The results also showed that HR and RPP increased significantly following both exercise protocols (P=0.001).

CONCLUSIONS

In summary, both CE and IE results in increased serum concentrations of hs-cTnT in sedentary men. However, this increase does not seem to be caused by the irreversible death of cardiomyocytes. CE resulted in a greater hs-cTnT concentration than IE.

The prognostic value of measurement of high-sensitive cardiac troponin T for mortality in a cohort of stable chronic obstructive pulmonary disease patients

Background

Cardiovascular disease (CVD) is a common comorbidity in chronic obstructive pulmonary disease (COPD). Cardiac troponin (cTn) elevation, indicating myocardial injury, is frequent during acute COPD exacerbations and associated with increased mortality. The prognostic value of circulating cTnT among COPD patients in the stable state of the disease is still unknown.

The purpose of the present study was to assess the association between circulating cTnT measured by a high sensitive assay (hs-cTnT) and all-cause mortality among patients with stable COPD without overt CVD.

Methods

In a prospective cohort study we included 275 patients from the Akershus University Hospital’s outpatient clinic and from Glittre, a pulmonary rehabilitation clinic. COPD-severity and cardiovascular risk factors were assessed, and time to all-cause death was recorded during a mean follow-up time of 2.8 years.

Results

One hundred-eighty patients (65%) had hs-cTnT concentrations ≥ the level of detection (5.0 ng/L) and 66 patients (24%) had hs-cTnT above the normal range (≥14.0 ng/L). In total, 47 patients (17%) died. hs-cTnT concentrations in the ranges <5.0, 5.0–13.9 and ≥14 ng/L were associated with crude mortality rates of 2.8, 4.4 and 11.0 per 100 patient-years, respectively. In adjusted analyses the hazard ratios (95% confidence intervals) for death were 1.7 (0.8–3.9) and 2.9 (1.2–7.2) among patients with hs-cTnT concentrations 5.0–13.9 and ≥14 ng/L, respectively, compared to patients with hs-cTnT <5.0 ng/L.

Conclusions

hs-cTnT elevation is frequently present in patients with stable COPD without overt CVD, and associated with increased mortality, independently of COPD-severity and other cardiovascular risk factors.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0319-9) contains supplementary material, which is available to authorized users.

High-sensitivity cardiac troponin T levels and risk of cerebral microbleeds in acute ischemic stroke patients with atrial fibrillation and/or rheumatic heart disease

BACKGROUND AND OBJECTIVE

Elevated high-sensitivity cardiac troponin T (hs-cTnT) levels are associated with coronary disease and small-vessel ischemic stroke through their associations with atherosclerosis. Considering the relationship between atherosclerosis and cerebral microbleeds (CMBs), the purpose of this study was to examine associations between serum hs-cTnT levels and risk of CMBs in acute ischemic stroke patients.

METHODS

This prospective study involved consecutively recruited acute ischemic stroke patients with atrial fibrillation and/or rheumatic heart disease treated at a large tertiary care hospital in southwestern China. Clinico-demographic data were collected and analyzed by logistic regression to identify the relationship between serum hs-cTnT levels and CMB occurrence and location.

RESULTS

In the final analysis, of 66 patients (27 males; mean age, 68.7years), 39 (59.1%) had CMBs. Hs-cTnT levels were not associated with risk of strictly lobar CMBs. However, after adjusting age, sex, current alcohol consumption, total cholesterol, hypertension, diabetes mellitus, prior antithrombotic therapy and NIHSS on admission, patients in the higher tertile were more likely to have CMBs and deep or infratentorial CMBs (P<0.05) compared with the lower hs-cTnT tertile.

CONCLUSION

Hs-cTnT may be an independent predictor for the occurrence of CMBs, particularly of deep or infratentorial CMBs. This finding justifies further research into how hs-cTnT levels may contribute to CMBs and potentially other subclinical small-vessel diseases.

Cardiac troponin T elevation at dialysis initiation is associated with all-cause and cardiovascular mortality on dialysis in patients without diabetic nephropathy

BACKGROUND

It is not known whether asymptomatic cardiac troponin T (cTnT) elevation is associated with all-cause or cardiovascular mortality in non-diabetic and advanced chronic kidney disease (CKD) patients.

METHODS

We measured cTnT in 248 consecutive patients at 1-2 weeks before dialysis initiation between March 2005 and August 2010 and followed them prospectively. A Cox proportional hazard model was used to investigate the relationship between cTnT and all-cause and cardiovascular mortality on dialysis.

RESULTS

The median age of the patients was 67 years (male 59.3 %), and the prevalence of diabetic nephropathy (DN) was 38.3 %. Asymptomatic cTnT elevation (>0.01 ng/mL) was observed in 196 (79 %) and 111 (73 %) patients among the overall patients and among patients without DN, respectively. A total of 51 patients died during a median follow-up period of 31.6 months. The cTnT level was associated with all-cause [hazard ratio (HR) 1.453; 95 % confidence interval (CI) 1.093-1.931; P = 0.010] and cardiovascular mortality [HR 1.973; 95 % CI 1.127-3.454; P = 0.017] on dialysis after extensive adjustment in the overall patient population. Patients without DN showed similar associations as those for the overall patient population (all-cause mortality: HR 1.566; 95 % CI 1.048-2.339; P = 0.029 and cardiovascular mortality: HR 2.657; 95 % CI 1.115-6.328; P = 0.027).

CONCLUSION

Asymptomatic cTnT elevation might be strongly associated with all-cause and cardiovascular mortality in patients without DN, as well as in the overall advanced CKD patients. We suggest that cardiovascular risk in patients with pre-dialysis CKD should be stratified according to cTnT levels.

Overexpression of Dyrk1A regulates cardiac troponin T splicing in cells and mice

The human heart expresses four isoforms of cardiac troponin T (cTnT) through alternative splicing of exons 4 and 5 of the cTnT gene. Alternative splicing of cTnT exon 5 is developmentally regulated. cTnT isoforms containing exon 5 are expressed in the fetal and neonatal heart but not in the mature heart. SRp55 is an essential splicing factor involved in cTnT exon 5 splicing and it is phosphorylated by Dyrk1A (dual specificity tyrosine phosphorylation regulated kinase 1A). In the present study, we found Dyrk1A interacted with SRp55 and enhanced its promotion of cTnT exon 5 inclusion. The shift from cTnT exon 5 inclusion to exclusion during development was delayed in the heart of Ts65Dn mice due to Dyrk1A overexpression. These results provide new insight into the role of Dyrk1A in the neonatal cardiac development.

The effect of cardiomyopathy mutation (R97L) in mouse cardiac troponin T on the muscle length-mediated recruitment of crossbridges is modified divergently by α- and β-myosin heavy chain

Hypertrophic cardiomyopathy mutations in cardiac troponin T (TnT) lead to sudden cardiac death. Augmented myofilament Ca(2+) sensitivity is a common feature in TnT mutants, but such observations fail to provide a rational explanation for severe cardiac phenotypes. To better understand the mutation-induced effect on the cardiac phenotype, it is imperative to determine the effects on dynamic contractile features such as the muscle length (ML)-mediated activation against α- and β-myosin heavy chain (MHC) isoforms. α- and β-MHC are not only differentially expressed in rodent and human hearts, but they also modify ML-mediated activation differently. Mouse analog of human TnTR94L (TnTR97L) or wild-type TnT was reconstituted into de-membranated muscle fibers from normal (α-MHC) and transgenic (β-MHC) mouse hearts. TnTR97L augmented myofilament Ca(2+) sensitivity by a similar amount in α- and β-MHC fibers. However, TnTR97L augmented the negative impact of strained crossbridges on other crossbridges (γ) by 22% in α-MHC fibers, but attenuated γ by 21% in β-MHC fibers. TnTR97L decreased the magnitude of ML-mediated recruitment of crossbridges (ER) by 37% in α-MHC fibers, but increased ER by 35% in β-MHC fibers. We provide a mechanistic basis for the TnTR97L-induced effects in α- and β-MHC fibers and discuss the relevance to human hearts.

Serum cardiac troponin T and effective blood flow in stable extracorporeal dialysis patients

Purpose

We examined the association between extracorporeal dialysis (ED)-related effective blood flow (eQB) and serum cardiac troponin T (cTnT) as a possible indicator of silent myocardial damage in stable ED patients.

Methods

In a cross-sectional study, cTnT was determined in 247 ED patients dialyzed using stable eQB and dialysate flow (QD). In a prospective study, 91 patients were switched from low-flux (LF) to high-flux (HF) hemodialysis (HD), and subsequently, the eQB increased, and the QD decreased; 65 patients continued LF-HD with stable eQB and QD. Clinical/laboratory evaluations were performed at 0, 15, 36, and 53 weeks from the start of the study.

Results

In the cross-sectional study, the main cTnT predictors were dialysis vintage, age, eQB, phosphorus, and C-reactive protein. Patients with cTnT levels in the highest quartile were excluded from the analysis, and subjects dialyzed with eQB ≤316 ml/min exhibited lower cTnT levels compared with patients dialyzed with higher eQB (P = 0.002). The all-cause and cardiac mortality rates of 154 patients, without changes in ED modality for up to 42 months, were associated with the initial cTnT concentrations but not with the initial eQB. In the prospective study, higher values for eQB and cTnT were observed during HF-HD at weeks 36 (P = 0.045) and 53 (P = 0.01) of the present study. The initial cTnT, ∆eQB, and ∆albumin influenced the ∆cTnT. The all-cause and cardiac mortality rates were not different between LF and HF groups at 21 months after the prospective study was completed.

Conclusion

In stable ED patients, higher eQB rates and QB/QD values might contribute to silent myocardial injury, particularly in patients with lower cTnT levels, but do not affect the outcome of ED patients.

Electronic supplementary material

The online version of this article (doi:10.1007/s11255-015-1165-z) contains supplementary material, which is available to authorized users.

Pathogenesis associated with a restrictive cardiomyopathy mutant in cardiac troponin T is due to reduced protein stability and greatly increased myofilament Ca2+ sensitivity

BACKGROUND

Dilated and hypertrophic cardiomyopathy mutations in troponin can blunt effects of protein kinase A (PKA) phosphorylation of cardiac troponin I (cTnI), decreasing myofilament Ca2+-sensitivity; however this effect has never been tested for restrictive cardiomyopathy (RCM) mutants. This study explores whether an RCM cardiac troponin T mutant (cTnT-ΔE96) interferes with convergent PKA regulation and if TnT instability contributes to greatly enhanced Ca2+-sensitivity in skinned fibers.

METHODS

Force of contraction in skinned cardiac porcine fiber and spectroscopic studies were performed.

RESULTS

A decrease of -0.26 and -0.25 pCa units in Ca2+-sensitivity of contraction after PKA incubation was observed for skinned fibers incorporated with WT or cTnT-ΔE96, respectively. To further assess whether cTnT-ΔE96 interferes solely with transmission of cTnI phosphorylation effects, skinned fibers were reconstituted with PKA pseudo-phosphorylated cTnI (cTnI-SS/DD.cTnC). Fibers displaced with cTnT-WT, reconstituted with cTnI-SS/DD.cTnC decreased Ca2+-sensitivity of force (pCa50=5.61) compared to control cTnI-WT.cTnC (pCa50=5.75), similarly affecting cTnT-ΔE96 (pCa50=6.03) compared to control \cTnI-WT.cTnC (pCa50=6.14). Fluorescence studies measuring cTnC(IAANS) Ca2+-affinity changes due to cTnT-ΔE96 indicated that higher complexity (thin filament) better recapitulates skinned fiber Ca2+ sensitive changes. Circular dichroism revealed reduced α-helicity and earlier thermal unfolding for cTnT-ΔE96 compared to WT.

CONCLUSIONS

Although ineffective in decreasing myofilament Ca2+-sensitivity to normal levels, cTnT-ΔE96 does not interfere with PKA cTnI phosphorylation mediated effects; 2) cTnT-ΔE96 requires actin to increase cTnC Ca2+-affinity; and 3) deletion of E96 reduces cTnT stability, likely disrupting crucial thin filament interactions.

GENERAL SIGNIFICANCE

The pathological effect of cTnT-ΔE96 is largely manifested by dramatic myofilament Ca2+-sensitization which still persists even after PKA phosphorylation mediated Ca2+-desensitization.

Cardiac Damage Biomarkers Following a Triathlon in Elite and Non-elite Triathletes

The purpose of the present study was to investigate cardiac damage biomarkers after a triathlon race in elite and non-elite athlete groups. Fifteen healthy men participated in the study. Based on performance, they were divided into elite athlete group (EG: n=7) and non-elite athlete group (NEG: n=8). Participants' blood samples were obtained during four periods: before, immediately, 2 hours and 7 days after finishing the race. creatine kinase (CK), creatine kinase-myoglobin (CK-MB), myoglobin, and lactate dehydrogenase (LDH) were significantly increased in both groups immediately after, and 2 hours after finishing the race (p<.05). CK, CK-MB, and myoglobin were completely recovered after 7 days (p<.05). Hematocrit (Hct) was significantly decreased in both groups (p<.05) 7 days after the race. LDH was significantly decreased in the EG (p<.05) only 7 days after the race. Homoglobin (Hb) was significantly decreased in the NEG (p<.05) only 2 hours after the race. Although cardiac troponin T (cTnT) was significantly increased in the EG but not in the NEG 2hours after the race (p<.05), there was no group-by-time interaction. cTnT was completely recovered in both groups 7 days after the race. In conclusion, cardiac damage occurs during a triathlon race and, is greater in elite than in non-elite. However, all cardiac damage markers return to normal range within 1 week.

The calculation of the cardiac troponin T 99th percentile of the reference population is affected by age, gender, and population selection: a multicenter study in Italy

BACKGROUND

The aim of this study is to determine the 99th upper-reference limit (URL) for cardiac troponin T (cTnT) in Italian apparently healthy subjects.

METHODS

The reference population was selected from 5 cities: Bolzano (n=290), Milano (CAMELIA-Study, n=287), Montignoso (MEHLP-Study, n=306), Pisa (n=182), and Reggio Calabria (MAREA-Study, n=535). Subjects having cardiac/systemic acute/chronic diseases were excluded. Participants to MEHLP project underwent cardiac imaging investigation. High-sensitive cTnT was measured with Cobas-e411 (Roche Diagnostics).

RESULTS

We enrolled 1600 healthy subjects [54.6% males; age range 10-90years; mean (SD): 36.4 (21.2) years], including 34.6% aged <20years, 54.5% between 20 and 64years, and 10.9% over 65years. In the youngest the 99th URL was 10.9ng/L in males and 6.8ng/L in females; in adults 23.2ng/L and 10.2ng/L; and in elderly 36.8ng/L and 28.6ng/L. After the exclusion of outliers the 99th URL values were significantly decreased (P<0.05) in particular those of the oldest (13.8ng/L and 14ng/L). MEHLP participants were divided in healthy and asymptomatic, according to known cardiovascular risk factors (HDL, LDL, glucose, C-reactive protein): the 99th URL of cTnT values of these subgroups was significantly different (19.5 vs. 22.7, P<0.05).

CONCLUSIONS

99th URL of cTnT values was strongly affected by age, gender, selection of subjects and the statistical evaluation of outliers.

In vivo effects of propyl gallate, a novel Ca(2+) sensitizer, in a mouse model of dilated cardiomyopathy caused by cardiac troponin T mutation

AIMS

We have previously demonstrated that propyl gallate has a Ca(2+) sensitizing effect on the force generation in membrane-permeabilized (skinned) cardiac muscle fibers. However, in vivo beneficial effects of propyl gallate as a novel Ca(2+) sensitizer remain uncertain. In the present study, we aim to explore in vivo effects of propyl gallate.

MAIN METHODS

We compared effects of propyl gallate on ex vivo intact cardiac muscle fibers and in vivo hearts in healthy mice with those of pimobendan, a clinically used Ca(2+) sensitizer. The therapeutic effect of propyl gallate was investigated using a mouse model of dilated cardiomyopathy (DCM) with reduced myofilament Ca(2+) sensitivity due to a deletion mutation ΔK210 in cardiac troponin T.

KEY FINDINGS

Propyl gallate, as well as pimobendan, showed a positive inotropic effect. Propyl gallate slightly increased the blood pressure without changing the heart rate in healthy mice, whereas pimobendan decreased the blood pressure probably through vasodilation via inhibition of phosphodiesterase and increased the heart rate. Propyl gallate prevented cardiac remodeling and systolic dysfunction and significantly improved the life-expectancy of knock-in mouse model of DCM with reduced myofilament Ca(2+) sensitivity due to a mutation in cardiac troponin T. On the other hand, gallate, a similarly strong antioxidant polyphenol lacking Ca(2+) sensitizing action, had no beneficial effects on the DCM mice.

SIGNIFICANCE

These results suggest that propyl gallate might be useful for the treatment of inherited DCM caused by a reduction in the myofilament Ca(2+) sensitivity.

FRET study of the structural and kinetic effects of PKC phosphomimetic cardiac troponin T mutants on thin filament regulation

FRET was used to investigate the structural and kinetic effects that PKC phosphorylations exert on Ca(2+) and myosin subfragment-1 dependent conformational transitions of the cardiac thin filament. PKC phosphorylations of cTnT were mimicked by glutamate substitution. Ca(2+) and S1-induced distance changes between the central linker of cTnC and the switch region of cTnI (cTnI-Sr) were monitored in reconstituted thin filaments using steady state and time resolved FRET, while kinetics of structural transitions were determined using stopped flow. Thin filament Ca(2+) sensitivity was found to be significantly blunted by the presence of the cTnT(T204E) mutant, whereas pseudo-phosphorylation at additional sites increased the Ca(2+)-sensitivity. The rate of Ca(2+)-dissociation induced structural changes was decreased in the C-terminal end of cTnI-Sr in the presence of pseudo-phosphorylations while remaining unchanged at the N-terminal end of this region. Additionally, the distance between cTnI-Sr and cTnC was decreased significantly for the triple and quadruple phosphomimetic mutants cTnT(T195E/S199E/T204E) and cTnT(T195E/S199E/T204E/T285E), which correlated with the Ca(2+)-sensitivity increase seen in these same mutants. We conclude that significant changes in thin filament Ca(2+)-sensitivity, structure and kinetics are brought about through PKC phosphorylation of cTnT. These changes can either decrease or increase Ca(2+)-sensitivity and likely play an important role in cardiac regulation.

Cardiac troponin in ischemic cardiomyocytes: intracellular decrease before onset of cell death

AIM

Cardiac troponin I (cTnI) and T (cTnT) are the most important biomarkers in the diagnosis of acute myocardial infarction (AMI). Nevertheless, they can be elevated in the absence of AMI. It is unclear if such elevations represent irreversible cardiomyocyte-damage or leakage from viable cardiomyocytes. Our objective is to evaluate whether cTn is released from viable cardiomyocytes in response to ischemia and to identify differences in the release of cTn and its molecular forms.

METHODS AND RESULTS

HL-1 cardiomyocytes (mouse) were subjected to ischemia (modeled by anoxia with glucose deprivation). The total contents and molecular forms of cTn were determined in culture media and cell lysates. Cell viability was assessed from the release of lactate dehydrogenase (LDH). Before the release of LDH, the intracellular cTn content in ischemic cells decreased significantly compared to control (52% for cTnI; 23% for cTnT) and was not matched by a cTn increase in the medium. cTnI decreased more rapidly than cTnT, resulting in an intracellular cTnT/cTnI ratio of 25.5 after 24 h of ischemia. Western blots revealed changes in the relative amounts of fragmented cTnI and cTnT in ischemic cells.

CONCLUSIONS

HL-1 cardiomyocytes subjected to simulated ischemia released cTnI and cTnT only in combination with the release of LDH. We find no evidence of cTn release from viable cardiomyocytes, but did observe a significant decrease in cTn content, before the onset of cell death. Intracellular decrease of cTn in viable cardiomyocytes can have important consequences for the interpretation of cTn values in clinical practice.

Cardiac troponin T in forensic autopsy cases

The aim of the present study was to describe the findings of postmortem serum and pericardial fluid (PF) cardiac troponin T (cTnT) in various causes of death with regard to the postmortem interval (PMI) and comorbid cardiovascular disease, using 101 autopsy cases with PMI of 8-141 h divided into 9 groups: cardiovascular disease (CVD), other diseases (OD), poisoning (P), asphyxia (A), drowning (D), hypothermia (H), thoracic trauma (TT), other trauma (OT) and fire fatalities (F). The results suggest that cTnT levels may help to differentiate cardiovascular death from poisoning and non-thoracic trauma, as well as to differentiate cardiovascular and other diseases as cause of death from drowning and hypothermia. However, the effect of PMI, unlike comorbid cardiovascular disease, has to be taken into account.

The role of cardiac biomarkers in the diagnosis and management of patients presenting with suspected acute coronary syndrome

Myocardial infarction (MI) is the leading cause of death in the developed world. Biomarkers have an essential role in diagnosis, risk stratification, guiding management and clinical decision making in the setting of patients presenting with signs and symptoms of MI. Cardiac troponin (cTn) rose to prominence during the 1990s and has evolved to be the cornerstone for diagnosis of MI. The current criteria for MI diagnosis include a rise and/or fall in cTn with at least one value above the 99th percentile of the upper reference limit. Along with cTn, the natriuretic peptides B-type natriuretic peptide (BNP) and amino-terminal proBNP (NT-proBNP) have an important role in determining prognosis and guiding management. As assays for cTn have been evolved that are capable of reliably detecting smaller and smaller quantities in the blood, a dilemma has emerged as to how to use this new information. Several studies have attempted to answer this question and have shown that these lower concentrations of cTn have important prognostic significance and, more importantly, that intervention in these patients leads to improved clinical outcomes. New algorithms incorporating BNP, NT-proBNP, and more sensitive cTn assays hold promise for more rapid diagnosis or rule-out of MI, allowing for appropriate management steps to be initiated and more efficient and effective utilization of healthcare resources.

Evaluation in an emergency department of rapid separator tubes containing thrombin for serum preparation prior to hs-cTnT and CK-MB analyses

Background

In our emergency department, we collect blood in Rapid Serum Tubes (RSTs; Becton Dickinson, Franklin Lakes, NJ), in which clotting times are reduced. We investigated the influence of RST use on cardiac troponin T (hs-cTnT) and creatine kinase-MB (CK-MB) test results, in comparison with the use of tubes featuring a separator gel containing a clotting activator (SSTs; Green-vac, Yongin, Korea).

Methods

Samples from 60 patients were divided into equal aliquots and placed into RSTs and SSTs; hs-cTnT and CK-MB concentrations were determined using an autoanalyzer (Elecsys 2010) running commercial assays (Roche Diagnostics, Penzberg, Germany). Between-tube differences in CK-MB and hs-cTnT values were compared using the paired t-test, and correlations among variables were evaluated by calculation of Spearman correlation coefficients (r values). Deming regression analysis was performed and Bland-Altman plots were constructed.

Results

The hs-cTnT and CK-MB test results obtained from samples placed into RSTs and SSTs did not differ (p > 0.1). The correlations between the concentrations of hs-cTnT and CK-MB in samples placed into RSTs and SSTs were good; both r values were unity (p < 0.001). Deming regression analysis yielded the equation: RST [hs-cTnT] = 0.98 SST [hs-cTnT] + 0.69 pg/ml; and RST [CK-MB] = 0.95 SST [CK-MB]–0.09 ng/ml. The biases of 1.4 pg/ml (95% CI: minus 8.1–10.7 pg/ml) for hs-cTnT levels and 0.249 ng/ml (95% CI: minus 0.682–1.681 ng/ml) for CK-MB levels assayed using either tube was acceptable.

Conclusion

The hs-cTnT and CK-MB test results did not significantly differ when either tube was used. RST tube use was associated with a short clotting time; this was an advantage in an emergency laboratory setting.

A combination of increased Rho kinase activity and N-terminal pro-B-type natriuretic peptide predicts worse cardiovascular outcome in patients with acute coronary syndrome. Int J Cardiol. 2013;167:2813-2819. [PMID: 22921817 DOI: 10.1016/j.ijcard.2012.07.007]

BACKGROUND

Recent experimental evidence suggests that the Rho/Rho-kinase (ROCK) system may play an important role in the pathogenesis of acute coronary syndrome (ACS) but there are little clinical data. This study examined if ROCK activity is increased in patients with acute coronary syndrome and if ROCK activity predicts long-term cardiovascular event.

METHOD

Blood samples were collected from 188 patients within 12h after admission for ACS (53% men; aged 70 ± 13) and from 61 control subject. The main outcome measures were all cause mortality, readmission with ACS or congestive heart failure (CHF) from presentation within around 2 years (mean:14.4 ± 7.2 months; range: 0.5 to 26 months).

RESULTS

ROCK activity increased in ST elevation myocardial infarction (STEMI, n=90) (3.33 ± 0.93), non-STEMI (NSTEMI, n=68) (3.37 ± 1.04) and unstable angina (UA, n=30) (2.53 ± 0.59) groups when compared with disease controls (n=31) (2.06 ± 0.38, all p<0.001) and healthy controls (n=30) (1.54 ± 0.43, all p<0.001). There were 24 deaths, 34 readmissions with ACS and 15 admissions with CHF within 2 years. Patients with a high N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high ROCK activity on admission had a five-fold risk of a cardiovascular event (RR: 5.156; 95% CI: 2.180-12.191) when compared to those with low NT-proBNP and low ROCK activity.

CONCLUSION

ROCK activity was increased in patients with ACS, particularly in those with myocardial infarction. The combined usage of both ROCK activity and NT-proBNP might identify a subset of ACS patients at particularly high risk.

Serum level of heart-type Fatty Acid-binding protein in patients with chronic renal failure

OBJECTIVES

Heart-type fatty acid binding-protein (H-FABP) has been reported to be a potential novel biochemical marker for the early diagnosis of acute myocardial infarction (AMI). The effect of kidney diseases on the renal handling of H-FABP has not yet been fully evaluated. The aim of this study was to compare the effect of renal failure on the level of H-FABP and cardiac troponin (cTnT) concentrations.

METHODS

The study population was a small group of 16 patients with renal failure (6 females, 10 males aged 30-70 years) on routine regular haemodialysis or peritoneal dialysis.

RESULTS

The mean ±SD of serum urea and creatinine concentration in this group of patients was 19 ±9.6 mmol/L and 531.3 ±231.2 mmol/L respectively. H-FABP was increased in all 16 patients (81 ±53.3μg/L). The cTnT was increased ≥ 0.1μg/L in 8 patients (50%), ≥ 0.2μg/L in 5 patients (31.3%), and ≥ 0.3μg/L in 1 patient (6%).

CONCLUSION

The diagnostic efficiency of H-FABP and cTnT for the diagnosis of AMI in the presence of renal failure may be limited and such patients may have high levels even in the absence of AMI.

Initial troponin level as a predictor of prognosis in patients with intracerebral hemorrhage

OBJECTIVE

It has been suggested that elevated cardiac troponin T (cTnT) level is a marker of increased risk of mortality in acute ischemic stroke and subarachnoid hemorrhage (SAH). However, the association of serum cTnT level and prognosis of intracerebral hemorrhage (ICH) has been sparsely investigated. The aim of this study was to identify the relationship between cTnT level and the outcome in patients with spontaneous ICH.

METHODS

We retrospectively investigated 253 patients identified by a database search from records of patients admitted in our department for ICH between January 1, 2003 and December 31, 2007. The patients were divided into 2 groups; the patients in group 1 (n=225) with serum cTnT values of 0.01 ng/mL or less, and those in group 2 (n=28) with serum cTnT values greater than 0.01 ng/mL.

RESULTS

The serum cTnT level was elevated in 28 patients. There were significant differences in sex, hypertension, creatine kinase-myocardial band, midline shift, side of hematoma, and presence of intraventricular hemorrhage between the 2 groups. Logistic regression analysis identified the level of consciousness on admission, cTnT and midline shift as independent predictors of hospital mortality.

CONCLUSION

Theses results suggest that increased serum cTnT level at admission is associated with in-hospital mortality and the addition of a serum cTnT assay to routine admission testing should be considered in patients with ICH.