Results of the multicenter, prospective, randomised STRENGTH (Study To evaluate the use of RENalGuard to proTect patients at High risk of acute kidney injury) study

Aim

Radio-contrast agents are widely used in coronary, peripheral and structural interventions. Use of these iodine-containing agents can be associated with contrast-induced acute kidney injury (CI-AKI) that can cause substantial morbidity and mortality. The RenalGuard system induces a forced diuresis with a matched hydration and has been shown beneficial in patients requiring coronary angiogram and PCI.

Methods

STRENGTH is a prospective, randomised (1:1), open-labeled, parallel-group, multicenter (10 centers in Germany and France) study where patients at high risk of CI-AKI were randomly assigned to RenalGuard® therapy or conventional strategy including preventive hydration before complex percutaneous cardiovascular intervention (PCI, peripheral and structural). In the RenalGuard arm, matched fluid replacement was started 60 minutes pre-procedure and maintained for up to 4 hours afterwards. Patients were given an initial i.v. bolus of up to 250 ml of normal saline over 30 minutes and then an i.v. bolus of furosemide (0.5 mg/kg). To be enrolled, patients had to have moderate to severe renal failure (defined as 15≤eGFR≤40 mL/min/m2) and a high-volume contrast requiring cardiovascular procedure (estimated contrast volume>3 times eGFR value). The main exclusion criterion was administration of iodine contrast media within 5 days before index procedure. The primary endpoint was CI-AKI defined as an increase in sCr ≥0.3 mg/dL or an increase of 25% of basal value or requiring dialysis within 5 days after procedure. The primary analysis for efficacy is performed in a modified intention-to-treat basis. The trial was designed and monitored by an independent CRO (Cardiovascular European Research Center, CERC, Massy, France).

Results

A total of 259 patients aged 79.1±8.8 yrs were included in the study. Among them, 129 were assigned to RenalGuard therapy and 130 to preventive saline hydration. Their mean baseline eGFR was 32 (25; 37) vs. 33 (25; 39) mL/min/m2, respectively (p=0.88). Total fluid intake volume within 24hrs before the procedure was 2383±1146 vs. 1386±842mL, respectively (p<0.0001). Procedure type was complex PCI (48%), TAVI (25%), peripheral intervention (18%), other structural intervention (9%) with no difference between groups (p=0.56). The total amount of contrast used for the procedure was 116.3±68.2mL in the RenalGuard arm vs. 104.1±56.7 mL in the conventional arm (p=0.26). A staged procedure was performed in 24 patients, including 16 in the RenalGuard and 8 in the control arm with a mean interval from the first intervention of 43±29 days and 24±19 days, respectively. For this second procedure, the total amount of contrast was 80±59 vs. 87±73mL.

Conclusion

The primary and secondary endpoints of the Study To evaluate the use of RENalGuard to proTect patients at High risk of CI-AKI comparing RenalGuard therapy to conventional hydration in 259 patients requiring complex percutaneous cardiovascular intervention will be presented.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): CERC

[Risk stratification and treatment of cardiac amyloidoses]

Cardiac amyloidoses are a heterogeneous group of cardiomyopathies that are resistant to treatment and are associated with a poor outcome. Standard heart failure treatment is usually not well tolerated and the underlying disease remains unaffected. The clinical picture is uncharacteristic. Cardiac amyloidosis is often associated with dysfunction of additional organs. Early cardiac amyloid involvement usually reveals left ventricular hypertrophy, impairment of longitudinal shortening and diastolic ventricular function. Without adequate therapy (bi-)ventricular hypertrophy will progress to severe systolic ventricular function decrease. The combination of low voltage pattern, left ventricular hypertrophy and granular sparkling is characteristic for advanced cardiac amyloid involvement. Cardiac magnetic resonance imaging and scintigraphy yield further information on the pattern and severity of cardiac involvement. In unclear cases (left ventricular) endomyocardial biopsy is necessary. Detection of early cardiac involvement and proper identification of patients at high risk for sudden cardiac death due to rapid progressive amyloidosis is still incompletely defined. Referral to specialized centers is strongly recommended.

Gender and age related predictive value of walk test in heart failure: Do anthropometrics matter in clinical practice?

BACKGROUND

The six-minute walk test (6 WT) is a valid and reliable predictor of morbidity and mortality in chronic heart failure (CHF) patients, frequently used as an endpoint or target in clinical trials. As opposed to spiroergometry, improvement of its prognostic accuracy by correction for height, weight, age and gender has not yet been attempted comprehensively despite known influences of these parameters.

METHODS

We recorded the 6 WT of 1035 CHF patients, attending clinic from 1995 to 2005. The 1-year prognostic value of 6 WT was calculated, alone and after correction for height, weight, BMI and/or age. Analysis was performed on the entire cohort, on males and females separately and stratified according to BMI (<25, 25-30 and >30 kg/m(2)).

RESULTS

6 WT weakly correlated with age (r=-0.32; p<0.0001), height (r=0.2; p<0.0001), weight (r=0.11; p<0.001), not with BMI (r=0.01; p=ns). The 6 WT was a strong predictor of 1-year mortality in both genders, both as a single and age corrected parameter. Parameters derived from correction of 6 WT for height, weight or BMI did not improve the prognostic value in univariate analysis for either gender. Comparison of the receiver operated characteristics showed no significant gain in prognostic accuracy from any derived variable, either for males or females.

CONCLUSION

The six-minute walk test is a valid tool for risk prediction in both male and female CHF patients. In both genders, correcting 6 WT distance for height, weight or BMI alone, or adjusting for age, does not increase the prognostic power of this tool.

Prognostic impact of peakVO2-changes in stable CHF on chronic beta-blocker treatment

BACKGROUND

Peak oxygen uptake (pVO2) is used for risk stratification in chronic heart failure (CHF), but little is known about the prognostic impact of pVO2-changes in patients on chronic beta-blocker (BBL) therapy. We therefore prospectively evaluated individual pVO2-changes at a 6-month interval in patients all receiving BBL.

METHODS

194 patients with stable CHF on stable medication were included (V1) and underwent clinical evaluation and exercise testing. Testing was repeated (V2) at 5.7+/-1.5 months after V1 and patients were followed >12 months after V2. Death or hospitalisation due to cardiac reasons was the predefined EP (EPP, end-point positive; n=62; EPN, end-point negative; n=113).

RESULTS

Initial characteristics did not differ between EPP and EPN. Multivariate cox regression analysis revealed that change of pVO2 (EPP: -0.6+/-2.6 ml/kg min; EPN: +2.5+/-3.3 ml/kg min; p<0.001) was independent to pVO2, LVEF, NTproBNP and NYHA at V2 for prediction of the combined end-point during follow-up. An increase of pVO2 by 10% was identified as an adequate cut-off value for risk stratification and ROC-analysis showed the significant incremental prognostic value of the determination of pVO2 changes in combination with pVO2.

CONCLUSIONS

Serial measurements of pVO2 yield additional information for risk stratification in clinically homogenous CHF patients receiving BBL. This is the first study demonstrating this fact within a narrow predefined interval with all patients on BBL.

Relevance of laser irradiance threshold in the induction of alkaline phosphatase in human osteoblast cultures

Induction of matrix synthesis by low-level laser has been demonstrated extensively. However, the question of dose- or power intensity-dependency is under-investigated. To address this issue we chose human osteoblast cell cultures and measured their alkaline phosphatase (ALP) activity after laser irradiation. The cell cultures were irradiated periodically by 690 nm radiation via optical transmission fiber-based laser needles, reaching into the culture dishes. The osteoblasts showed no induction of ALP activity when we used a single laser needle stimulation with a laser irradiance of 51 mW/cm(2), an increase of approximately 43% at 102 mW/cm(2) irradiance (two needles per well) and a ninefold increase at 204 mW/cm(2) irradiance (four needles per well), leaving the temperature of the culture medium unaffected. We concluded that the osteoblastic response in ALP activity to a laser stimulus shows a logarithmic relationship, with a distinct threshold, rather than a linear dose-dependency. Secondly, the laser irradiance, rather than the dose, is relevant for the impact of the laser.

Differentiated expression patterns of growth factors in routine formalin-fixed endomyocardial biopsies in the early postoperative phase after heart transplantation

BACKGROUND

Platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF) seem to play a key role in immunological reactions shortly after heart transplantation (HTx). The aim of this study was to analyze the time course of the expression of PDGF A and B, PDGF-receptor alpha (PDGF-Ralpha) and beta, aFGF, and bFGF on formalin-fixed routine endomyocardial biopsies.

PATIENTS AND METHODS

Right ventricular endomyocardial biopsies were obtained from 36 heart transplant recipients up to 2 weeks after HTx. According to the clinical course in the first postoperative year, 3 groups were formed: (1) clinically uneventful course (n = 12); (2) cardiac/systemic infections (n = 12); (3) acute rejection (n = 12). The growth factor expression was examined immunohistochemically.

RESULTS

In the early phase after HTx, PDGF A, PDGF B, PDGF-Ralpha, and PDGF-Rbeta were predominantly expressed in endothelial cells. The main expression of PDGF-Ralpha and bFGF was found in cardiomyocytes, endothelial cells, and smooth muscle cells. During the first 2 postoperative weeks, PDGF A, PDGF B, and PDGF-Rbeta showed a similar time course of expression: A significantly elevated expression in the first week was followed by a decrease in the second week. In the rejection group, PDGF A was significantly elevated after the first week.

CONCLUSIONS

The increased expression of PDGF in the first postoperative week can be interpreted as an unspecific reaction to peritransplant injury. The prolonged expression of PDGF A, PDGF B, and PDGF-Rbeta showed that there were ongoing immunological reactions in the transplant during week 2. The persistence of elevated PDGF A expression might be of prognostic value in terms of a risk factor for either infection or rejection.

Acupuncture treatment improves nerve conduction in peripheral neuropathy

The etiology of peripheral neuropathy (PN) often remains elusive resulting in a lack of objective therapeutic strategies. We conducted a pilot study to evaluate the therapeutic effect of acupuncture on PN as measured by changes in nerve conduction and assessment of subjective symptoms. One hundred and ninety-two consecutive patients with PN as diagnosed by nerve conduction studies (NCS) were evaluated over a period of 1 year. Of 47 patients who met the criteria for PN of undefined etiology, 21 patients received acupuncture therapy according to classical Chinese Medicine as defined by the Heidelberg Model, while 26 patients received the best medical care but no specific treatment for PN. Sixteen patients (76%) in the acupuncture group improved symptomatically and objectively as measured by NCS, while only four patients in the control group (15%) did so. Three patients in the acupuncture group (14%) showed no change and two patients an aggravation (10%), whereas in the control group seven showed no change (27%) and 15 an aggravation (58%). Importantly, subjective improvement was fully correlated with improvement in NCS in both groups. The data suggest that there is a positive effect of acupuncture on PN of undefined etiology as measured by objective parameters.

S100A1 gene transfer in myocardium

S100A1, a Ca superset2+-binding protein of the EF-hand type, is preferentially expressed in myocardial tissue and has been shown to enhance cardiac contractile performance by regulating both sarcoplasmic reticulum (SR) Ca superset2+-handling and myofibrillar Ca superset2+-responsiveness. In cardiac disease, the expression of S100A1 is dynamically altered as it is significantly down-regulated in end stage human heart failure (HF), and it is up-regulated in compensated hypertrophy. Therefore, the delivery of a transgene encoding for S100A1 to the myocardium might be an attractive strategy for improving cardiac function in HF by replacing lost endogenous S100A1. In this study we sought to test whether exogenous S100A1 gene delivery to alter global cardiac function is feasible in the normal rabbit heart. An adenoviral S100A1 transgene (AdvS100A1) also containing the green fluorescent protein (GFP) was delivered using an intracoronary injection method with a dose of 5 x 10 superset11 total virus particles (tvp) (n = 8). Rabbits treated with either a GFP-only adenovirus (AdvGFP) or saline were used as control groups (n = 11 each). Seven days after global myocardial in vivo gene delivery hemodynamic parameters were assessed. S100A1 overexpression as a result of the intracoronary delivery of AdvS100A1 significantly increased left ventricular (LV) +dP/dt subsetmax, -dP/dt subsetmin and systolic ejection pressure (SEP) compared to both control groups after administration of isoproterenol (0.1, 0.5 and 1.0 microg/kgBW/min), while contractile parameters remained unchanged under basal conditions. These results demonstrate that global myocardial in vivo gene delivery is possible and that myocardial S100A1 overexpression can increase cardiac performance. Therefore, substitution of down-regulated S100A1 protein expression levels may represent a potential therapeutic strategy for improving the cardiac performance of the failing heart.

The Eurotransplant High-Urgency Heart Transplantation Program: An Option for Patients in Acute Heart Failure?

OBJECTIVE

The Eurotransplant High-Urgency (HU) Heart Transplantation Program allows urgent heart transplants to be carried out in rapidly deteriorating patients with acute-to-chronic heart failure on the elective waiting list. But do the results of HU heart transplantation justify performing primary heart transplantation in these critically ill patients and offer an acceptable outcome?

METHODS

Between 2000 and 2004, 64 heart transplantations (HTx) (32 elective and 32 HU-HTx) were performed in our department. After having been accepted in an auditing process based on HU criteria, intensive care patients in NYHA functional class IV (cardiac index 1.7 l/min/qm BS), in end-organ failure (creatinine 1.5 mg/dl), and with catecholamine dependence (dobutamine 8 microg/kg/min), are given priority with respect to organ allocation, and their data were compared to data from elective patients from the same period.

RESULTS

HU requests were accepted in 97 % of cases. Two requests were not accepted, and both patients with contraindications for assist device implantation died within one week. The HU patients were 100 % in NYHA class IV, 93 % of the elective patients were in NYHA class III. Waiting time on the HU list was 13 days, and 7 of these patients died before HTx. Following heart transplantation, survival rates at 30 days and at one year of the HU group were 88 % and 85 % versus 94 % and 93 % in the elective group.

CONCLUSIONS

This study shows that end-stage heart failure patients in the HU program can be transplanted primarily with good results if an organ is available in time. We are still in the position where the HU program only manages the organ shortage; there are still too many patients on the waiting list who die before receiving a donor organ.

[Telemonitoring in chronic heart failure patients. Which diagnostic finding prevents hospital readmission?]

Heart failure exhibits a significant clinical and health economic problem. The implementation of new therapeutic strategies favorably affecting the course of disease is still insufficient in day-to-day practice. Thus, the usage of telemedicine offers a central instrument for service and information, so that an optimized therapy can be achieved by consequent surveillance of the patient with chronic heart disease. Predefined vital parameters are automatically transmitted to the telemedicine center; if individually predefined limits are exceeded, therapeutic means are immediately initiated. For the patient, the center is attainable 24 h throughout the year in case he experiences cardio-pulmonary symptoms. This patient-oriented usage of technology should not replace the physician-patient relationship, but improves and supports the participation and self-management of patients. Furthermore, the results show that this technology can significantly reduce the amount of emergency physician services, hospital admissions and primary care physician visits, and displays for health economics purposes a clearly more cost-effective treatment strategy, while allowing for additional costs inherent to the system. The usage of telemonitoring in chronic heart failure patients may be a trendsetting form of care, which can be used to drastically optimize the information and data flow between patient, hospital and primary care physician individually and at any time.

Effects of intracoronary low-dose enalaprilat as an adjunct to primary percutaneous transluminal coronary angiography in acute myocardial infarction

Bradykinin accumulation is a potent cardioprotective mechanism underlying angiotensin-converting enzyme (ACE) inhibition in ischemia and/or reperfusion injury. There is, however, concern about treatment with ACE inhibitors in the very early phase of acute myocardial infarction (AMI) due to adverse systemic hemodynamic effects. We tested the hypothesis that cardiac bradykinin metabolism can be influenced by very low doses of intracoronary ACE inhibitors without harmful systemic effects in patients with AMI. Twenty-two patients with AMI in Killip classes II to III who underwent primary percutaneous transluminal coronary angiography (PTCA) were randomized to intracoronary enalaprilat (50 microg) or saline, given immediately after reopening of the infarct-related artery. Hemodynamics and electrocardiograms were monitored continuously and samples for determination of ACE activity, angiotensin II, bradykinin, kininogen, and cardiac marker proteins were collected from pulmonary arterial and central venous blood. Enalaprilat had no adverse effects on systemic hemodynamics, but rather stabilized arterial pressure and cardiac rhythm during reperfusion. Enalaprilat induced a 70% reduction of ACE activity and a significant increase of bradykinin in pulmonary arterial blood. Angiotensin II was not significantly affected by enalaprilat either in pulmonary arterial or in central venous blood. Myoglobin release was lower and the duration of reperfusion arrhythmias was significantly reduced in the enalaprilat group (p <0.05). Thus, in this pilot study, intracoronary enalaprilat infusion in the infarct-related artery is feasible in the setting of primary angioplasty and is safe and well tolerated. Effective cardiac ACE inhibition can be achieved by low-dose intracoronary enalaprilat, which primarily causes a potentiation of bradykinin.

S100A1: a regulator of myocardial contractility

S100A1, a Ca(2+) binding protein of the EF-hand type, is preferentially expressed in myocardial tissue and has been found to colocalize with the sarcoplasmic reticulum (SR) and the contractile filaments in cardiac tissue. Because S100A1 is known to modulate SR Ca(2+) handling in skeletal muscle, we sought to investigate the specific role of S100A1 in the regulation of myocardial contractility. To address this issue, we investigated contractile properties of adult cardiomyocytes as well as of engineered heart tissue after S100A1 adenoviral gene transfer. S100A1 gene transfer resulted in a significant increase of unloaded shortening and isometric contraction in isolated cardiomyocytes and engineered heart tissues, respectively. Analysis of intracellular Ca(2+) cycling in S100A1-overexpressing cardiomyocytes revealed a significant increase in cytosolic Ca(2+) transients, whereas in functional studies on saponin-permeabilized adult cardiomyocytes, the addition of S100A1 protein significantly enhanced SR Ca(2+) uptake. Moreover, in Triton-skinned ventricular trabeculae, S100A1 protein significantly decreased myofibrillar Ca(2+) sensitivity ([EC(50%)]) and Ca(2+) cooperativity, whereas maximal isometric force remained unchanged. Our data suggest that S100A1 effects are cAMP independent because cellular cAMP levels and protein kinase A-dependent phosphorylation of phospholamban were not altered, and carbachol failed to suppress S100A1 actions. These results show that S100A1 overexpression enhances cardiac contractile performance and establish the concept of S100A1 as a regulator of myocardial contractility. S100A1 thus improves cardiac contractile performance both by regulating SR Ca(2+) handling and myofibrillar Ca(2+) responsiveness.

Translocation of S100A1(1) calcium binding protein during heart surgery

Myocardial ischemia during cardiopulmonary bypass terminated by reperfusion generally leads to different degrees of damage of the cardiomyocytes induced by transient cytosolic Ca(2+) overload. Recently, much attention has been paid to the role of heart-specific Ca(2+)-binding proteins in the pathogenesis of myocardial ischemia-reperfusion injury. S100A1 is a heart-specific EF-hand Ca(2+)-binding protein that is directly involved in a variety of Ca(2+)-mediated functions in myocytes. The aim of our study was to investigate the localization and translocation of S100A1 in the human heart under normal (baseline) conditions and after prolonged ischemia and reperfusion of the myocardium. Our data suggest that S100A1 is directly involved in the transient perioperative myocardial damage caused by ischemia during open heart surgery in humans. Given its role in the contractile function of muscle cells, this S100 protein could be an important "intracellular link" in ischemia-reperfusion injury of the heart.

Separation of low molecular weight proteins with SDS-PAGE using taurine as a new trailing ion

Taurine as an alternative trailing ion for tricine yields an identical resolution but reduces the running time by 15% and the power consumption by 15% compared to tricine. Therefore cooling of gels is more effective in SDS PAGE with taurine and artefacts due to oxidation of proteins can thus be reduced.

Cardiac troponin T levels at 96 hours reflect myocardial infarct size: a pathoanatomical study

We determined the utility of single-point measurements of circulating cardiac troponin T (cTnT) for the noninvasive estimation of infarct size in 16 beagle dogs after left anterior descending artery (LAD) ligation. Pathoanatomical infarct sizes were determined by the triphenyltetrazolium chloride method and correlated with serum concentration changes of cTnT. Peak cTnT levels (14.10 +/- 4.71 microg/l) were reached after 110 +/- 21 h. A significant correlation was found between peak cTnT levels (p = 0.0001, r = 0. 83) or cumulative cTnT levels and relative infarct size (p = 0.0010, r = 0.72). A single cTnT measurement 96 h after LAD ligation was equally predictive of infarct size (p = 0.0010, r = 0.74) as peak or cumulative cTnT levels derived from serial sampling. cTnT levels at 96 h may thus be useful for practical and cost-effective estimation of infarct size.

Right ventricular upregulation of the Ca(2+) binding protein S100A1 in chronic pulmonary hypertension

The Ca(2+) binding protein S100A1 increases the Ca(2+) release from the sarcoplasmatic reticulum by interacting with the ryanodine receptor. In order to understand whether this effect might be operative in the early course of hypertrophy, when myocardium is able to meet increased workload, we investigated the expression of S100A1 in a model of moderate right ventricular hypertrophy. The pulmonary arteries of nine pigs were embolised three times with Sephadex G-50. After 70 days, all pigs showed a moderate pulmonary hypertension. Right ventricular tissue of embolised animals showed a significant increase of connective tissue and enlargement of myocyte diameters. In controls, we found a differential expression of S100A1 with significantly lower S100A1 protein levels in right ventricular compared to left ventricular tissue. In pulmonary hypertension, S100A1 expression increased significantly in hypertrophied right ventricles while it was unchanged in left ventricular tissue. No change was observed in the expression of SERCA2a and phospholamban. Our data show, for the first time, that moderate pressure overload results in an upregulation of S100A1. This may reflect an adaptive response of myocardial Ca(2+) homeostasis to a higher workload.

Purification of the Ca2+-binding protein S100A1 from myocardium and recombinant Escherichia coli

S100A1 is a new regulatory protein of myocardial contractility that is differentially expressed in early and late stages of myocardial hypertrophy. In order to further investigate the multiple functions of S100A1 in various assay systems we developed a new strategy for isolating biologically active S100A1 protein. After EDTA extraction of myocardium or recombinant bacteria, S100A1 was purified by Octyl-Sepharose hydrophobic interaction chromatography and HiTrapQ anion-exchange chromatography yielding 1.4-2.0 mg/100 g wet tissue and 0.7-1.0 mg/100 ml bacterial culture. Native porcine as well as human recombinant S100A1 revealed biological activity in physiological and biochemical assays.

Quantitative bedside assay for cardiac troponin T: a complementary method to centralized laboratory testing

BACKGROUND

In the evaluation of chest pain patients, whole blood bedside assays of highly specific cardiac molecules may be an attractive alternative to centralized clinical chemistry testing. We now report on an optimized test strip device for cardiac troponin T (cTnT) that can be analyzed by a cardiac reader for quantitative assessment of the test result.

METHODS AND RESULTS

The cTnT test strip reader measures, via a CCD camera, the reflectance of the signal line. For quantitative analysis, a calibration curve was constructed from 1030 samples of 252 consecutive patients with acute coronary syndromes. In a method comparison of 140 samples, the quantitative results of the cTnT test strip reader correlated closely with the results of the cTnT ELISA (r = 0.98; y = 0.85x + 0. 002). Within-run and day-to-day (n = 10) mean CVs were between 11% and 16%, respectively. The cross-reactivity with skeletal troponin T was <0.02%. In patients with myocardial infarction, 45% and 91% of all samples were positive on admission and at 4-8 h after the onset of symptoms, respectively. ROC curve analysis demonstrated a comparable efficiency of the cTnT test strip reader and the laboratory-based cTnT ELISA in patients with suspected myocardial infarction.

CONCLUSIONS

It is now possible to quantitatively determine cTnT at the patient's bedside with a rapid and convenient test device. This will facilitate the diagnostic work up of patients with suspected myocardial cell necrosis.

Cardiac troponin T in patients with end-stage renal disease: absence of expression in truncal skeletal muscle

In patients with end-stage renal disease (ESRD), the serum concentration of cardiac troponin T (cTnT) may be increased without cardiac ischemia. One reason for this unexplained increase could be the extracardiac expression of cTnT. However, truncal skeletal muscle biopsies of five patients with ESRD showed no evidence of the expression of either cTnT mRNA (reverse transcription-PCR) or protein (immunoblot, immunofluorescence). We also measured the serum concentration of cTnT in 97 patients with ESRD. The serum cTnT concentration determined in both first and second generation cTnT assays was significantly lower P <0.01 in patients with a low cardiac risk than in patients with positive indicators of coronary artery disease. The correlation between cTnT and indicators of coronary artery disease is consistent with the hypothesis that cTnT in the serum of patients with ESRD originates from the heart.

Differential myocardial abundance of collagen type I and type III mRNA in dilated cardiomyopathy: effects of myocardial inflammation

OBJECTIVE

The collagen subtypes I (Col I) and III (Col III) are essential components of the cardiac extracellular matrix (ECM) maintaining the functional integrity of the heart. Histological, immunohistological, and biochemical studies, however, demonstrate characteristical changes of the ECM in dilated cardiomyopathy, myocarditis, ischemic cardiomyopathy, and hypertensive heart disease.

METHODS

In order to investigate possible effects of inflammatory processes on mRNA abundance of Col I and Col III, we examined 24 patients with the presumptive clinical diagnosis of dilated cardiomyopathy (EF = 30 +/- 11%). 12 Patients were classified as idiopathic dilated cardiomyopathy without any evidence of myocardial inflammation; the remaining 12 patients were classified as inflammatory cardiomyopathy due to the immunohistologically documented inflammatory myocardial process.

RESULTS

Quantification of reverse transcription polymerase chain reaction (RT-PCR) products revealed significant differences as to the mRNA abundance ratio Col III/Col I between subgroups of patients with inflammatory cardiomyopathy (1.16 +/- 0.18) and idiopathic dilated cardiomyopathy (2.77 +/- 0.65) regardless of left ventricular dysfunction (p < or = 0.05).

CONCLUSION

It is not yet known, whether different Col III/Col I ratios differentially influence diastolic compliance. Our data suggest that inflammatory mechanisms seen in inflammatory cardiomyopathy influence the mRNA abundance of collagen subtypes I and III.

Subtractive cloning and characterization of DRAL, a novel LIM-domain protein down-regulated in rhabdomyosarcoma

A subtractive cloning procedure was used to characterize the molecular changes involved in transformation of normal myoblasts to rhabdomyosarcoma (RMS) cells. Here we describe the cloning of DRAL, a novel LIM-domain protein expressed in primary myoblasts but down-regulated in the RMS cell line RD. DRAL is a LIM-only protein with five LIM domains whereby one LIM domain consists only of the second half of the consensus motif. Interestingly, down-regulation of DRAL was not confined to the RD RMS cells, but was a phenomenon extended to other RMS cell lines of both embryonal and alveolar subtype, and to some breast cancer cell lines. Analysis of the expression pattern in normal human tissues revealed that DRAL is expressed at high levels in the heart, suggesting an important function in the specification of the terminally differentiated phenotype of heart muscle cells. Immunofluorescence studies using an antibody directed against recombinant DRAL localized the protein predominantly in the nucleus of cultured cells. On the basis of these results, we conclude that down-regulation of DRAL correlates with the tumor phenotype of RMS cells.

Improved troponin T ELISA specific for cardiac troponin T isoform: assay development and analytical and clinical validation

The first generation of troponin T ELISA (TnT 1) can yield false-positive results in patients with severe skeletal muscle injury. Therefore, a cardiac-specific second-generation troponin T ELISA (TnT 2) was developed, in which the cross-reactive antibody 1B10 has been replaced by a high-affinity cardiac-specific antibody M11.7. No cross-reactivity of TnT 2 was observed with purified skeletal muscle troponin T (1000 micrograms/L) or in test samples from 43 marathon runners and 24 patients with rhabdomyolysis and highly increased creatine kinase. TnT 2 was increased > 0.2 microgram/L in 5 of 40 patients with renal failure and in 4 of 20 muscular dystrophy patients. The detection limit is 0.012 microgram/L. Day-to-day imprecision (CV) within the range 0.19-14.89 micrograms/L was < 5.8%. In 4955 patients without myocardial damage, 99.6% had TnT < 0.10 microgram/L. Assay comparison (TnT 1 vs TnT 2) over the whole concentration range (i.e., in 323 samples from AMI-suspected patients) showed a slope, intercept, and standard error of estimate (Sey) of 1.18, 0.01 micrograms/L, and 0.81 microgram/L, respectively.

Troponin T: a diagnostic marker for myocardial infarction and minor cardiac cell damage

The diagnosis of acute myocardial infarction is straightforward when anginal pain is accompanied by typical ECG changes and in these patients measurements of cardiac markers are unnecessary in deciding whether thrombolytic therapy is appropriate. Cardiac markers in patients with acute ischaemic coronary syndromes, however, may serve to identify a high risk subgroup of patients with small acute infarctions or minor myocardial damage. In many patients with chest pain a valid diagnosis of myocardial cell injury depends on the result of biochemical assays. In 30% of patients with unstable angina, troponin T is elevated although myocardial infarction was ruled out by cardiac enzymes and ECG recordings. The outcome of these patients at 4 weeks and 6 months follow-up is not different from that of patients with definite myocardial infarction. To guide therapeutic decisions on these patients a troponin T test result needs to be available rapidly. The rapid troponin T test strip assay, which allows the determination of troponin T levels in whole blood at the patient's bedside, can be performed conveniently in the emergency room or in laboratories with less sophisticated equipment and has the potential to aid in the triage of chest pain patients and the selection of therapeutic strategies.

Induction of apoptosis in rhabdomyosarcoma cells through down-regulation of PAX proteins

The expression of a number of human paired box-containing (PAX) genes has been correlated with various types of tumors. Novel fusion genes encoding chimeric fusion proteins have been found in the pediatric malignant tumor alveolar rhabdomyosarcoma (RMS). They are generated by two chromosomal translocations t(2;13) and t(1;13) juxtaposing PAX3 or PAX7, respectively, with a forkhead domain gene FKHR. Here we describe that specific down-regulation of the t(2;13) translocation product in alveolar RMS cells by antisense oligonucleotides results in reduced cellular viability. Cells of embryonal RMS, the other major histiotype of this tumor, were found to express either wild type PAX3 or PAX7 at elevated levels when compared with primary human myoblasts. Treatment of corresponding embryonal RMS cells with antisense olignucleotides directed against the mRNA translational start site of either one of these two transcription factors similarly triggers cell death, which is most likely due to induction of apoptosis. Retroviral mediated ectopic expression of mouse Pax3 in a PAX7 expressing embryonal RMS cell line could partially rescue antisense induced apoptosis. These data suggest that the PAX3/FKHR fusion gene and wild-type PAX genes play a causative role in the formation of RMS and presumably other tumor types, possibly by suppressing the apoptotic program that would normally eliminate these cells.

Altered expression of the Ca(2+)-binding protein S100A1 in human cardiomyopathy

The Ca(2+)-binding protein S100A1 displays a tissue-specific expression pattern with highest levels in myocardium and has been shown to interact with SR-proteins regulating the Ca(2+)-induced Ca(2+)-release. We, therefore, hypothesized that changes in S100A1 gene expression might correlate with the pathognomonic finding of altered SR Ca(2+)-transients in human end stage heart failure. To test this hypothesis, we established a specific and sensitive method to analyse S100A1 expression in cardiac tissues by employing hydrophobic interaction-chromatography and reversed-phase high performance liquid chromatography (RP-HPLC) coupled with Electron-Ionisation-Mass-Spectrometry (ESI-MS). Porcine myocardium showed a differential expression of S100A1 with relative protein concentrations of 62 +/- 8% in the right ventricle (RV), 57 +/- 9% in the right atrium (RA), and 25 +/- 15% in the left atrium (LA) as compared to the left ventricle (LV) (100 +/- 10%; P < 0.001). Northern blot analyses confirmed a likewise distribution of porcine S100A1 mRNA implying a regulation on the transcriptional level. Analyses of left ventricular specimen of patients with end stage heart failure (CHF, n = 6; CHD, n = 6) revealed significantly reduced S100A1 protein levels, while integration of S100A1 peaks after RP-HPLC yielded two groups of patients with < 76% (69 +/- 7%, n = 6) and < 35% (23 +/- 12%, n = 6) respectively as compared to controls (100 +/- 8%, n = 3). These data demonstrate for the first time that S100A1 is differentially expressed in myocardium and that in human cardiomyopathy a reduced expression of S100A1 may contribute to a compromised contractility.

Development and characterization of a rapid assay for bedside determinations of cardiac troponin T

BACKGROUND

The appearance of cardiac proteins in blood is the most specific and sensitive indicator of acute myocardial cell necrosis. The measurement of cardiac markers, however, is time consuming and requires sophisticated equipment. To facilitate the biochemical detection for acute myocardial cell necrosis, a whole-blood rapid assay device for cardiac troponin T detection was developed that provides a test result within 20 minutes.

METHODS AND RESULTS

Monoclonal antibody M7 is labeled with gold particles, and antibody 1B10 is labeled with biotin. Both antibodies, as well as buffer substances and detergents, are adsorbed onto paper fleeces mounted below an application well. Heparinized blood (160 microL) applied to this well solubilizes the dry chemistry reagents. Blood cells are separated from plasma via a glass-fiber fleece. The immunocomplexes formed are concentrated within the reading zone by binding of the biotin-labeled antibody with streptavidine immobilized to the test device. Troponin T bound to the test device serves as a control. The detection limit of this assay is 0.18 microgram/L with a cross-reactivity with skeletal troponin T of 0.5%. In clinical analyses involving 25 healthy volunteers, 62 patients with chest pain but without myocardial ischemia, 35 patients with acute myocardial infarction, 24 patients with minor myocardial cell damage due to radiofrequency ablation, and 35 patients with unstable angina, the rapid assay was comparable to the troponin T enzyme immunoassay in regard to sensitivity and specificity.

CONCLUSIONS

This newly developed assay allows accurate, rapid, and convenient diagnosis of acute myocardial cell necrosis.

[Catecholamines, myofibrillary degeneration of the heart muscle and cardiac troponin T in various types of agony]

The stress of agony (the death struggle) induces a rise in serum catecholamines. High doses of catecholamines cause myofibrillar degeneration (MFD), a form of cardiac injury. Severely damaged cardiac myocytes release troponin T (TnT), a myofibrillar cardiac protein, into the circulation. We studied serum catecholamine levels, MFD and TnT in 119 medico-legal autopsy cases. Catecholamine levels increased with the duration of agony: In the instantaneous death cases, the levels were similar to levels in humans at rest, whereas the levels in prolonged agony were comparable to concentrations found in humans in acute maximal stress. Still, it was not possible to infer the duration of agony from the catecholamine level in an individual case. The exceptionally high dopamine levels found in the group 'resuscitation and/or intensive care before death 'were most likely caused by antemortal treatment with dopamine. Slight MFD was diagnosed in nearly all hearts; its severity was neither related to catecholamine levels nor to duration of agony. TnT, not found in blood of healthy people, was present in nearly all postmortem samples, indicating autolytic effects. Heart blood contained more TnT than femoral blood. We could not detect a relationship between the serum cardiac troponin T level and MFD; but cardiac deaths had significantly higher levels of TnT in heart blood than deaths from other causes. The postulated interrelation between catecholamines, MFD and TnT was not evident from the results.

[Successful use of a heparinoid (danaparoid sodium) for heparin-induced thrombocytopenia type II in aortic valve reoperation]

The 29-year-old, heroin-addicted patient received an aortic valve prosthesis (SJM) 10 years ago because of aortic valve stenosis III. One year after surgical treatment he refused to take Phenprocoumon and thus received no anticoagulation for 9 years. The patient was hospitalized due to cardial decompensation and thrombosis of the aortic valve prosthesis was diagnosed. Under heparinization, he developed heparin-induced thrombocytopenia type II, which disappeared after changing the medication to Danaparoid-Sodium. In order to avoid any further heparin exposure, we also carried out the surgical replacement of the aortic valve prosthesis under anticoagulation with Danaparoid-Sodium.

Intracellular compartmentation of troponin T: release kinetics after global ischemia and calcium paradox in the isolated perfused rat heart

The marked differences in troponin T serum concentrations observed in patients with reperfused and non-reperfused myocardial infarction may be due to a perfusion dependent wash-out of an unbound fraction of cardiac troponin T. To test the release kinetics of troponin T experimentally, the isolated rat heart (Langendorff preparation) was damaged either by the calcium paradox or by no-flow ischemia. Following membrane damage by the calcium paradox troponin T (TNT) showed the same release kinetics in the coronary effluent as the cytosolic markers creatine kinase (CK) or lactate dehydrogenase (LDH). Peak levels of troponin T (282 +/- 58 micrograms/l), CK (6754 +/- 1642 U/l), and LDH (5817 +/- 1730 U/l) occurred 5 min after onset of reperfusion with calcium containing buffers and returned to 9.9%, 1.3%, and 1% of their respective peak levels within 55 min of reperfusion. During reperfusion after no-flow ischemia different release kinetics were found for cytosolic enzymes and troponin T. After 60 min of ischemia, troponin T levels in the coronary effluent increased over the entire reperfusion period of 55 min, almost doubling the 5 min value (191%). In contrast, cardiac enzymes rapidly declined to 18% (CK) and 23% (LDH) of their respective 5 min values at the end of reperfusion. Light microscopy after reperfusion with carbon black revealed a complete and homogeneous reperfusion of Langendorff hearts after no-flow ischemia. Immunoblot analysis confirmed the release of an undegraded 39 kDa troponin T molecule, both after global ischemia and the calcium paradox. These data indicate that prolonged ischemia induces a continuous liberation of cardiac troponin T, most probably from disintegrating myofibres, whereas membrane damage leads almost exclusively to leakage of a functionally unbound troponin T pool. These findings may explain the biphasic serum concentration changes of cardiac troponin T in patients with reperfused myocardial infarction.

Assessment of reperfusion of the infarct zone after acute myocardial infarction by serial cardiac troponin T measurements in serum

BACKGROUND

The purpose of this study was to derive indices of reperfusion and non-reperfusion after acute myocardial infarction (AMI) from changes in serum concentrations of cardiac troponin T and to test the predictive value of these indices.

METHODS

The indices were derived from a retrospective analysis of changes in serum troponin T concentration in 71 patients given thrombolytic treatment who had immediate and late angiography (group 1). These troponin T indices were first tested in a blinded and prospective study of 53 consecutive patients eligible for thrombolytic therapy (group 2). They were then used for the non-invasive assessment of reperfusion of AMI in 48 patients (group 3).

RESULTS

In group 1 troponin T serum concentration curves were biphasic in patients who had reperfusion < or = 5.8 h after the onset of symptoms. Release of the cytosolic troponin T pool resulted in a peak at 14 h and ended at 38 h. The probability of reperfusion was > 95% when the ratio of peak cytosolic troponin T concentration to concentration at 38 h (PV1/38) exceeded 1.42 or the ratio of troponin T concentration at 14 h to that at 38 hours (14/38) exceeded 1.09. The probability of the presence of non-reperfused AMI was < 5% when troponin T PV1/38 and 14/38 ratios were < 0.99 and < 0.84 respectively. These discriminatory values of troponin T indices correctly classified (efficiency 96%) 48 of the 53 group 2 patients in whom immediate and late angiography were performed. When troponin T indices were used to classify 48 group 3 patients who were not studied by immediate angiography, thrombolytic therapy was deemed to have been successful in 82% of the treated patients, with spontaneous recanalisation in 11% and 23% of the non-treated patients assessed by PV1/38 and 14/38 respectively.

CONCLUSION

The PV1/38 or 14/38 ratios of serum troponin T concentration indicated the effectiveness of thrombolytic therapy in achieving reperfusion of AMI.

Troponin T release after heart transplantation

BACKGROUND

For the diagnosis of myocardial cell damage the measurement of the serum concentrations of myofibrillar antigens has several potential advantages over the assessment of traditional serological markers. These include the expression of myofibrillar antigens as cardiospecific isoforms and their high intracellular concentrations. Recently a sensitive and specific enzyme immunoassay for cardiac troponin T has been developed that shows little cross-reactivity with skeletal isoforms.

OBJECTIVE

To characterise myocardial cell damage after orthotopic heart transplantation, concentration of circulating troponin T were measured prospectively in serial blood samples from 19 consecutive patients taken during the first three months after transplantation.

RESULTS

Mean (SD) serum concentrations of cardiac troponin T reached a maximum of 3.6 (1.8) micrograms/l at 7.1 (4.2) days after transplantation and remained higher than 0.5 micrograms/l (twice the detection limit of the assay) in all patients for at least 43 days (mean (SD) 59 (20) days). There was considerable variation in cumulative troponin T release (area under the concentration curve) between the patients (ranging from 27 to 150 micrograms x days/l) that was not related to the total ischaemic time before transplantation or to the patient's renal or hepatic function, preoperative cardiac diseases, major histocompatibility complex matching or the number of complications related to rejection.

CONCLUSIONS

Because the half life of cardiac troponin T serum is 2 h the current data show that antigen continued to be released from implanted hearts during the first postoperative months in quantities similar to minor Q wave myocardial infarction. Troponin T release after transplantation continued for much longer than after myocardial infarction or other cardiac surgery. Processes other than perioperative ischaemic damage must be responsible for the considerable individual differences in the release of cardiac troponin T.

Development and in vitro characterization of a new immunoassay of cardiac troponin T

We describe a new one-step enzyme immunoassay of troponin T that uses two specific monoclonal antibodies and streptavidin-coated tubes as the solid phase. The monoclonal antibodies were obtained by conventional hybridoma technology, with human troponin T as antigen. The identity of the cardiac troponin T antigen was confirmed by analysis of the amino acid composition and by partial sequence analysis. The specificity of the monoclonal antibodies for cardiac troponin T was proved by immunoblot analysis and displacement curves. The capture antibody is labeled with biotin. The second antibody is conjugated to horseradish peroxidase (EC 1.11.1.7). The assay [Enzymun-TestR system (Boehringer Mannheim GmbH)] is performed in only 90 min at room temperature; the measuring range for troponin T is 0.1 to 15 micrograms/L. The assay shows excellent between-run precision (CV = 3.3-4.9%).

Development and In Vitro Characterization of a New Immunoassay of Cardiac Troponin T

We describe a new one-step enzyme immunoassay of troponin T that uses two specific monoclonal antibodies and streptavidin-coated tubes as the solid phase. The monoclonal antibodies were obtained by conventional hybridoma technology, with human troponin T as antigen. The identity of the cardiac troponin T antigen was confirmed by analysis of the amino acid composition and by partial sequence analysis. The specificity of the monoclonal antibodies for cardiac troponin T was proved by immunoblot analysis and displacement curves. The capture antibody is labeled with biotin. The second antibody is conjugated to horseradish peroxidase (EC 1.11.1.7). The assay [Enzymun-TestR system (Boehringer Mannheim GmbH)] is performed in only 90 min at room temperature; the measuring range for troponin T is 0.1 to 15 micrograms/L. The assay shows excellent between-run precision (CV = 3.3-4.9%).