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    <title>Balk, A.H.M.M.</title>
    <link>http://repub.eur.nl/res/aut/1337/</link>
    <description>List of Publications</description>
    <language>en</language>
    <image>
      <url>http://repub.eur.nl/static-eur/img/logo.png</url>
      <title>RePub, Erasmus University Rotterdam</title>
      <link>http://repub.eur.nl</link>
    </image>
    <item>
      <title>Clinical implications of chronic hepatitis e virus infection in heart transplant recipients (Article)</title>
      <link>http://repub.eur.nl/res/pub/38982/</link>
      <pubDate>2013-01-01T00:00:00Z</pubDate>
      <description>Background: Recent reports have shown that hepatitis E virus (HEV) infection can become chronic in solid-organ transplant recipients, but few studies have systematically investigated the clinical consequences of this chronic HEV infection in solid-organ transplant (SOT) recipients. Methods: We have undertaken an in-depth study of 6 chronic HEV-infected heart transplant recipients to gain further insight into the clinical, biochemical and virologic presentation of this disorder. Results: In 6 patients (2.3%) chronic HEV infection, genotype 3, was identified. Immunosuppression in these patients was tacrolimus-based, combined with either everolimus or prednisolone and/or mycophenolate mofetil. Median follow-up after case detection was 26 months (range 21 to 40 months). All chronic HEV cases had elevated liver enzyme values. IgM antibodies at presentation were positive in 2 of 6 (33%) patients. Liver histology in 4 of 6 (67%) patients showed advanced fibrosis within 2 years after infection. One patient spontaneously cleared the HEV infection: 1 after dose reduction of immunosuppressive therapy and 3 during ribavirin therapy. One patient has yet to clear the virus and remains on ribavirin therapy. Conclusions: Chronic HEV infection in heart transplant (HTx) recipients may lead to rapid fibrosis of the liver. We advise additional HEV RNA screening in solid-organ transplant recipients with elevated liver enzymes, because antibody production is often delayed, as demonstrated in these patients. Dose reduction of immunosuppressive therapy should be the first intervention strategy to achieve viral clearance in chronic HEV-infected immunocompromised patients. Ribavirin treatment should be considered in cases of chronic HEV. </description>
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      <title>Indications and outcome of implantable cardioverter-defibrillators for primary and secondary prophylaxis in patients with noncompaction cardiomyopathy (Article)</title>
      <link>http://repub.eur.nl/res/pub/34183/</link>
      <pubDate>2011-08-01T00:00:00Z</pubDate>
      <description>Prophylactic ICDs for Noncompaction Cardiomyopathy. Background: Noncompaction cardiomyopathy (NCCM) is a rare, primary cardiomyopathy, with initial presentation of heart failure, emboli, or arrhythmias, including sudden cardiac death. Implantable cardioverter-defibrillators (ICDs) are frequently used for primary and secondary prevention in different cardiomyopathy patients, but data about ICD in NCCM are scarce. The aim of this study was, therefore, to investigate ICD indications and outcomes in NCCM patients. Methods and Results: We collected prospective data from our NCCM cohort (n = 77 pts, mean age: 40 ± 14 years). ICD was implanted in 44 (57%) patients with NCCM according to the current ICD guidelines for nonischemic cardiomyopathies: in 12 for secondary prevention (7 × ventricular fibrillation, 5 × sustained ventricular tachycardia [VT]) and in 32 patients for primary prevention (heart failure/severe LV dysfunction). During a mean follow-up of 33 ± 24 months, 8 patients presented with appropriate ICD shocks due to sustained VT after median 6.1 [1-16] months. This included 4 of 32 (13%) patients in the primary prevention group and 4 of 12 (33%) in the secondary prevention group (P = 0.04). 9 patients presented with inappropriate ICD therapy: 6 (19%) in the primary and 3 (25%) in the secondary prevention group, at a median follow-up of 4 (2-23) months. Conclusions: In our cohort of NCCM patients, an ICD was frequently implanted for primary or secondary prevention of sudden cardiac death. At follow-up, frequent appropriate ICD therapy was observed in both groups, supporting the application of current ICD guidelines for primary and secondary prevention of sudden cardiac death in NCCM. </description>
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      <title>Identifying patients at risk of death or hospitalisation due to worsening heart failure using decision tree analysis: Evidence from the Trans-European Network-Home-Care Management System (TEN-HMS) Study (Article)</title>
      <link>http://repub.eur.nl/res/pub/33650/</link>
      <pubDate>2011-07-04T00:00:00Z</pubDate>
      <description>Objectives: To stratify patients recently discharged from hospital with heart failure (HF) according to their risk of death and/or hospitalisation for worsening HF (WHF), to enable timely and appropriate monitoring and intervention. Methods: Data from the TEN-HMS study were used in this analysis. Chi-square automatic interaction detector (CHAID) decision trees were constructed using a 10-fold cross-validation to predict events at 1-year and compared with logistic regression (LR) models using ROC curve analysis. Results: 284 patients were used for training and 160 patients available at 4-month for validation. Amino-terminal pro-brain natriuretic peptide (NT-proBNP) was the strongest predictor of mortality identifying groups with high (&gt; 13,492 pg/ml), medium (3127-13,492 pg/ml) and low (≤3127 pg/ml) risk, followed by MI, systolic blood pressure, age, heart rhythm, study randomisation group and serum sodium. NT-proBNP was also the strongest predictor for death or hospitalization for WHF identifying groups with high (&gt; 13,492 pg/ml), medium (584-13,492 pg/ml), and low (≤584 pg/ml), followed by MI, creatinine, heart rhythm, potassium and urea. CHAID trees tended to perform better than LR-models (prediction of the composite outcome: ROC area with 95% CI, 0.797 (0.745-0.849) for CHAID and 0.738 (0.680-0.796) for LR-model; p = 0.041; prediction of mortality: 0.892 (0.853-0.931) for CHAID and 0.858 (0.813-0.904) for LR; p = 0.15). Conclusions: Decision trees are an alternative classification method used to differentiate risk in patients with HF. The resultant models are concise, free of subjective variables and understood easily by clinicians. Further exploration of their potential and validation in other data-sets is justified. </description>
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      <title>Bradycardiomyopathy: The case for a causative relationship between severe sinus bradycardia and heart failure (Article)</title>
      <link>http://repub.eur.nl/res/pub/20097/</link>
      <pubDate>2010-07-01T00:00:00Z</pubDate>
      <description>Bradycardiomyopathy. A 28-year-old man presented with progressive fatigue. Physical examination and ECG revealed severe sinus bradycardia. Echocardiography showed features of noncompaction cardiomyopathy and moderate aortic valve regurgitation. We hypothesized that the chronic volume overload exaggerated by prolonged diastole due to the bradycardia resulted in heart failure and noncompaction cardiomyopathy look-alike features. After implantation of an AAI pacemaker, his symptoms and signs of cardiomyopathy were fully recovered.</description>
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      <title>Double intra-atrial connections in a patient late after orthotopic heart transplantation (Article)</title>
      <link>http://repub.eur.nl/res/pub/28302/</link>
      <pubDate>2010-06-01T00:00:00Z</pubDate>
      <description>Atrial tachycardias occurring late after orthotopic heart transplantation are frequently caused by an ongoing atrial tachycardia in the recipient remnant atrium that is associated with intra-atrial muscle band connections between the 2 atrial compartments. The standard approach for most centers that treat these patients is to identify and disconnect these intra-atrial connections. We present a patient where double intra-atrial connections were capable of different degrees of stimulus propagation from the recipient remnant atrium to the donor atrial compartment. After the ablation of both intra-atrial connections, we also ablated the index arrhythmia in the recipient remnant atrium. This case presentation draws attention to the possibility of the presence of multiple intra-atrial connections. </description>
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      <title>Prediction of Appropriate Defibrillator Therapy in Heart Failure Patients Treated With Cardiac Resynchronization Therapy (Article)</title>
      <link>http://repub.eur.nl/res/pub/27437/</link>
      <pubDate>2010-01-01T00:00:00Z</pubDate>
      <description>The necessity of implantable cardioverter-defibrillator (ICD) implantation in patients with systolic heart failure (HF) who undergo cardiac resynchronization therapy (CRT) may be questioned. The aim of this study was to identify patients at low risk for sustained ventricular arrhythmia. One hundred sixty-nine consecutive patients with HF (mean age 60 ± 12 years, 125 men, 73% in New York Heart Association class III) referred for CRT and prophylactic, primary prevention ICD implantation underwent baseline clinical and echocardiographic assessment and regular device follow-up. The primary study end point was appropriate ICD therapy. During a mean follow-up period of 654 ± 394 days, 35 patients (21%) had sustained ventricular arrhythmias requiring appropriate ICD therapy. Of the 3 patients who experienced sudden cardiac death, 2 had been treated with appropriate ICD therapy before sudden cardiac death. In a multivariate model, only history of nonsustained ventricular tachycardia (p = 0.001), a severely (&lt;20%) decreased left ventricular ejection fraction (p = 0.001), and digitalis therapy (p = 0.08) independently predicted appropriate ICD therapy. Patients with 0 (n = 46), 1 (n = 36), 2 (n = 73), and 3 (n = 14) risk factors for appropriate ICD therapy had a 7%, 14%, 27%, and 64% and 0%, 6%, 10%, and 43% incidence of appropriate ICD therapy for ventricular arrhythmias and for rapid ventricular tachycardia or ventricular fibrillation, respectively. In conclusion, apart from commonsense considerations (age and significant co-morbidities), ICD addition seems ineffective in CRT patients without nonsustained ventricular tachycardia, digoxin therapy, and severely reduced left ventricular systolic function. </description>
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      <title>Inadequate immune regulatory function of CD4+CD25bright+FoxP3+ T cells in heart transplant patients who experience acute cellular rejection (Article)</title>
      <link>http://repub.eur.nl/res/pub/16400/</link>
      <pubDate>2009-04-27T00:00:00Z</pubDate>
      <description>BACKGROUND.: CD4CD25FoxP3 regulatory T cells are suppressors of antigen-activated immune reactivity. Here, we assessed the clinically relevant role of these cells in the control of immune responses directed to a transplanted heart. METHODS.: We investigated the phenotype and function of peripheral CD4CD25FoxP3 T cells in heart transplant patients free from acute rejections (n=9) and in rejectors (n=12) before and during acute cellular rejection. RESULTS.: Between rejectors and nonrejectors, the proportion of CD4CD25 T cells and of FoxP3 cells within this population was comparable. Yet, CD4CD25FoxP3 T cells of rejectors had a higher CD127 expression than those of nonrejectors (P=0.0001). Depletion of CD4CD25 T cells from peripheral blood mononuclear cells increased the antidonor proliferative response of both nonrejectors (P≤0.0005) and rejectors (P≤0.03). In rejectors, however, only a 2-fold increase was measured, whereas the nonrejectors' response became 14 times higher (P=0.002). Reconstitution of CD4CD25 T cells only suppressed the overall antidonor proliferative response of CD25 responder cells of nonrejectors significantly (P=0.001). Moreover, the percentage inhibition of the response was higher in nonrejectors than in rejectors (P=0.02). Analyses of pretransplant samples revealed that CD4CD25 T cells of rejectors already had a lower suppressive capacity than those of nonrejectors before transplantation (P=0.04). CONCLUSION.: CD4CD25FoxP3 T cells of heart transplant patients who experience acute rejection had an up-regulated CD127 expression and an inadequate regulatory function compared with those of nonrejecting patients. Our observations suggest that the function of circulating CD4CD25FoxP3 regulatory T cells may be pivotal for the prevention of acute cellular rejection after clinical heart transplantation.</description>
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      <title>Donor-specific immune regulation by CD8+ lymphocytes expanded from rejecting human cardiac allografts (Article)</title>
      <link>http://repub.eur.nl/res/pub/24859/</link>
      <pubDate>2009-02-01T00:00:00Z</pubDate>
      <description>To assess whether regulatory T cells are present in rejecting human cardiac allografts, we performed functional analyses of graft lymphocytes (GLs) expanded from endomyocardial biopsies (EMB; n = 5) with histological signs of acute cellular rejection. The GL cultures were tested for their proliferative capacity and regulatory activity on allogeneic-stimulated peripheral blood mononuclear cells (PBMC) of the patient (ratio PBMC:GLs = 5:1). Three of these GL cultures were hyporesponsive to donor antigens and suppressed the antidonor proliferative T-cell response of PBMC, but not the anti-third-party response. Interestingly, it was the CD8+GL subset of these cultures that inhibited the antidonor response (65-91% inhibition of the proportion of proliferating cells); the CD4+GLs of the expanded GL cultures were not suppressive. In conclusion, CD8+GLs expanded from rejecting human cardiac allografts can exhibit donor-specific immune regulatory activities in vitro. We suggest that during acute cellular rejection, GLs may not only consist of graft-destructing effector T cells, but also of cells of the CD8+type with the potential to specifically inhibit antidonor immune reactivity. </description>
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      <title>Blood dendritic cell levels and phenotypic characteristics in relation to etiology of end-stage heart failure: Implications for dilated cardiomyopathy (Article)</title>
      <link>http://repub.eur.nl/res/pub/25042/</link>
      <pubDate>2009-01-09T00:00:00Z</pubDate>
      <description>Background: Dysregulation of dendritic cell (DC) mediated immune responses towards auto-antigens, is considered an important feature in the maintenance of experimentally induced heart failure (HF). In order to evaluate the role of blood DCs in cardiomyopathies of different origins, we examined myeloid (mDC) and plasmacytoid (pDC) subset levels and maturation characteristics, according to HF severity and etiology in humans. Methods: Absolute numbers of mDCs and pDCs in 12 New York Heart Association (NYHA) class-II, 28 NYHA class III-IV HF patients and 18 healthy controls, were studied by 4-colour whole blood flow cytometry. Results: End-stage (NYHA III-IV) HF patients had comparable circulating DC subset levels to NYHA-II patients and controls. However, within the NYHA III-IV group total DC levels in patients with non-ischemic dilated cardiomyopathy (DCM) were higher (P &lt; 0.001) than in patients with coronary artery disease (CAD), hypertrophic cardiomyopathy (HCM) or other HF etiology. This was due to a significant increase of primarily mDCs (P &lt; 0.0001) and to a lesser extent of pDCs (P &lt; 0.05) in idiopathic DCM patients, independent of systolic or diastolic cardiac dysfunction. Maturation marker CD83 and lymphoid homing chemokine receptor CCR7 surface expression was enhanced only on mDCs, but not pDCs from DCM patients (P &lt; 0.05), compared to patients with CAD, HCM or other underlying cardiac pathophysiology. Conclusions: Total blood DC levels in end-stage HF are elevated in patients with DCM. Whole blood DC characterisation may lead to new insights into the pathophysiology of idiopathic DCM in humans. </description>
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      <title>Donor-derived mesenchymal stem cells remain present and functional in the transplanted human heart (Article)</title>
      <link>http://repub.eur.nl/res/pub/25110/</link>
      <pubDate>2009-01-01T00:00:00Z</pubDate>
      <description>Mesenchymal stem cells (MSC) are characterized by their multilineage differentiation capacity and immunosuppressive properties. They are resident in virtually all tissues and we have recently characterized MSC from the human heart. Clinical heart transplantation offers a model to study the fate of transplanted human MSC. In this study, we isolated and expanded MSC from heart tissue taken before, and 1 week up to 6 years after heart transplantation. MSC from posttransplantation tissue were all of donor origin, demonstrating the longevity of endogenous MSC and suggesting an absence of immigration of recipient MSC into the heart. MSC isolated from transplanted tissue showed an immunophenotype that was characteristic for MSC and maintained cardiomyogenic and osteogenic differentiation capacity. They furthermore preserved their ability to inhibit the proliferative response of donor-stimulated recipient peripheral blood mononuclear cells. In conclusion, functional MSC of donor origin remain present in the heart for several years after transplantation. </description>
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      <title>Susceptibility of human mesenchymal stem cells to tacrolimus, mycophenolic acid, and rapamycin (Article)</title>
      <link>http://repub.eur.nl/res/pub/29225/</link>
      <pubDate>2008-11-15T00:00:00Z</pubDate>
      <description>BACKGROUND.: Mesenchymal stem cells (MSC) have multilineage differentiation and immunomodulatory capacities and are potentially useful for therapeutic applications, such as tissue regeneration and control of alloreactivity. MSC are present in most tissues including the transplantable organs. It is therefore unavoidable that MSC will be exposed to immunosuppressive drugs in a clinical transplantation setting. The molecular targets of these drugs are expressed in MSC, but the effect of their inhibition on MSC functioning is unknown. METHODS.: MSC were isolated and expanded from heart tissue and the effects of the calcineurin inhibitor tacrolimus, the cell cycle inhibitor mycophenolic acid (MPA), and the mammalian target of rapamycin inhibitor on MSC survival, proliferation, differentiation, and immunosuppressive capacity were examined. RESULTS.: Short-term exposure to the immunosuppressants did not induce toxicity or apoptosis in MSC, but high-dose tacrolimus induced toxicity after 7 days. MPA and rapamycin inhibited MSC proliferation at therapeutic doses. The immunosuppressants had differential effects on the differentiation capacity of MSC. Tacrolimus reduced the expression of troponin T type 2 and desmin during cardiomyogenic differentiation of MSC, whereas MPA decreased the deposition of calcified minerals during osteogenic differentiation. Rapamycin stimulated lipid production during adipogenic differentiation. Unexpectedly, MSC had adverse effects on the immunosuppressive efficacy of tacrolimus and rapamycin. There was no such effect of MSC on the function of MPA. Preincubation of MSC with tacrolimus increased the immunosuppressive capacity of MSC. DISCUSSION.: This study demonstrates that therapeutic concentrations of immunosuppressive drugs affect MSC function. MSC affect the efficacy of immunosuppressive medication. These findings are important for potential clinical use of MSC in combination with immunosuppressants. </description>
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      <title>Tele-guidance of chronic heart failure patients enhances knowledge about the disease. A multi-centre, randomised controlled study (Article)</title>
      <link>http://repub.eur.nl/res/pub/30244/</link>
      <pubDate>2008-11-01T00:00:00Z</pubDate>
      <description>Background: New strategies are required to optimize care in increasing numbers of chronic heart failure patients. The aim of this randomised trial was to evaluate a remote guidance system. Methods: Intervention group patients received a home TV-channel providing educational materials. Tele-guidance was performed by a Medical Service Centre. Control group patients were followed by cardiologists and HF-nurses. Primary endpoints were total days in hospital for all causes and days alive and out of hospital. Secondary endpoints were: quality of life and knowledge of disease and self care. Results: 214 patients were enrolled, median age was 66 years, 89% had systolic LV dysfunction, and 90% were in NYHA class II or III. The mean LVEF was 31%. Over a mean follow-up duration of 288 days, there were 199 hospital admissions in 105 patients. Comparison of the groups revealed no differences for the primary outcomes or for QoL or self care behaviour. Knowledge about heart failure however, increased significantly more in the Intervention group (p &lt; 0.001). Conclusion: Tele-guidance may play a role in the management of heart failure patients since it takes over some of the tasks of HF-nurses. This may facilitate delivery of optimal care to more patients with the same level of experienced staff. </description>
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      <title>Four-year follow-up of treatment with intramyocardial skeletal myoblasts injection in patients with ischaemic cardiomyopathy (Article)</title>
      <link>http://repub.eur.nl/res/pub/29271/</link>
      <pubDate>2008-06-01T00:00:00Z</pubDate>
      <description>Aims: Studies reporting improved left ventricular (LV) function of percutaneous skeletal myoblast (SkM) injection in patients with ischaemic cardiomyopathy had follow-up not exceeding 12 months, and did not include a control group. Our group has reported evidence for myoblast efficacy in the first five out of the 14 treated patients. The objective of the present evaluation was to assess if these effects were sustained at long-term follow-up. We compared function of patients treated with SkM 4 years earlier with a matched control group. Secondary endpoints included mortality, NYHA class, N-terminal pro-B-natriuretic peptide levels, incidence of arrhythmias, and quality of life. Methods and results: Fourteen patients with ischaemic cardiomyopathy who underwent SkM injection were compared with 28 non-randomized control patients matched for age, sex, location, and extent of myocardial infarction. Contrast echocardiography and tissue Doppler imaging (TDI) was performed to compare global and regional LV function. At 4-year follow-up, three patients (21%) had died in the treated group and 11 patients (39%) in the control group (P = 0.8). In the survivors, LV ejection fraction (EF) was 35 ± 10% and 37 ± 9% in the SkM group and 36 ± 8% and 36 ± 6% in the controls at baseline and 4 years follow-up, respectively (P = 0.96 between groups at follow-up). TDI-derived systolic velocity in the injected sites was 5.4 ± 1.8 cm/s in the SkM group when compared with 5.1 ± 1.6 cm/s in corresponding sites in the control group (P = 0.47). None of the secondary endpoints showed a difference between the groups. However, in the patients fitted with an internal cardioverter defibrillator, more arrhythmias leading to interventions occurred in the treated group than in the control group, 87% and 13%, respectively (P = 0.015). Conclusion: Percutaneous intramyocardial SkM injection in ischaemic cardiomyopathy has no sustained positive effect on resting global or regional LV function, respectively, at 4-year follow-up. Moreover, the procedure may induce a higher risk of developing serious arrhythmias, but larger patient series are required before more precise characterization of the safety and efficacy profile of the procedure is possible. </description>
    </item> <item>
      <title>FOXP3 mRNA expression analysis in the peripheral blood and allograft of heart transplant patients (Article)</title>
      <link>http://repub.eur.nl/res/pub/30029/</link>
      <pubDate>2008-01-01T00:00:00Z</pubDate>
      <description>Previously, we demonstrated in heart transplant patients that FOXP3, a gene required for the development and function of regulatory T cells, was highly expressed in the graft during an acute cellular rejection. In this study, we analyzed whether the FOXP3 gene expression in the peripheral blood also reflects anti-donor immune responses, and therefore may provide clues for non-invasive detection of non-responsiveness or acute rejection. We examined the FOXP3 expression patterns of peripheral blood mononuclear cells (PBMC; n = 69) of 19 heart transplant patients during quiescence and rejection in comparison with those of endomyocardial biopsies (EMB; n = 75) of 24 heart transplant patients. While the FOXP3 mRNA levels were abundantly expressed in rejecting EMB (ISHLT rejection grade &gt; 1R) compared with EMB without histological evidence of myocardial damage (ISHLT rejection grade 0R-1R; p = 0.003), no association with rejection or non-responsiveness was found for the FOXP3 mRNA levels in the peripheral blood. Thus, in contrast to intragraft FOXP3 gene expression, the peripheral FOXP3 mRNA levels lack correlation with anti-donor immune responses in the graft, and, consequently, FOXP3 does not appear to be a potential candidate gene for non-invasive diagnosis of non-responsiveness or rejection. </description>
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      <title>Predictors of Cardiac Events After Cardiac Resynchronization Therapy With Tissue Doppler-Derived Parameters (Article)</title>
      <link>http://repub.eur.nl/res/pub/36546/</link>
      <pubDate>2007-12-01T00:00:00Z</pubDate>
      <description>Background: To evaluate the prognostic value of tissue Doppler imaging (TDI)-derived parameters (E/E′ ratio and Tei index) in heart failure (HF) patients who underwent cardiac resynchronization therapy (CRT). Methods and Results: The study comprised 74 consecutive HF patients (mean age 60 ± 11 years) who underwent CRT. Echocardiography including TDI measurements was performed in all patients at baseline and 3 months after CRT. During a median follow-up period of 720 days (range 210 to 1020 days), 21 patients (28%) had events (8 deaths, and hospitalization for HF in the remaining 13). From the baseline clinical and echocardiography data, univariable Cox-regressions analysis revealed that only diabetes (hazard ratio [HR] 3.703, P &lt; .01), E/A ratio (HR 3.492, P &lt; .001), and E/E′ ratio (HR 1.130, P &lt; .001) were predictors for cardiac events. From the 3-month follow-up data, the E/A ratio (HR 2.988, P &lt; .005), E/E′ ratio (HR 1.170, P &lt; .001), left ventricular ejection fraction (HR 0.835, P &lt; .01), deceleration time (HR 0.977, P &lt; .05), and the Tei index (HR 15.784, P &lt; .001) were predictors for cardiac events. After multivariable analysis, only diabetes (HR 5.544, P &lt; .05), the 3-month E/E′ ratio (HR 1.229, P &lt; .001), and change in Tei index (HR 32.174, P &lt; .001) were independent predictors for cardiac events. Patients with a high baseline and 3-month follow-up E/E′ ratio had an 88% cardiac event rate. Conclusions: The Tei index and E/E′ ratio are independent predictors of poor response and cardiac events after CRT. </description>
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      <title>Human heart, spleen, and perirenal fat-derived mesenchymal stem cells have immunomodulatory capacities (Article)</title>
      <link>http://repub.eur.nl/res/pub/36989/</link>
      <pubDate>2007-08-01T00:00:00Z</pubDate>
      <description>Mesenchymal stem cells (MSCs) have important tissue repair functions and show potent immunosuppressive capacities in vitro. Although usually isolated from the bone marrow, MSCs have been identified in other tissues, including the skin and liver. In the present study, we isolated and characterized MSCs from human heart, spleen, and perirenal adipose tissue. MSCs from these different tissue sites were similar to those derived from bone marrow in that they expressed comparable levels of the cell-surface markers CD90, CD105, CD166, and HLA class I, were negative for CD34, CD45, HLA class II, CD80, and CD86 expression, and were capable of osteogenic and adipogenic differentiation. Like bone marrow-derived MSCs, MSCs from these different tissue sources inhibited the proliferation of alloactivated peripheral blood mononuclear cells (PBMCs), giving 85%, 79%, 79%, and 81% inhibition, respectively. Also in line with bone marrow-derived MSCs they inhibited proliferative responses of PBMCs to phytohemagglutinin, a nonspecific stimulator of lymphocyte proliferation, and reduced-memory T lymphocyte responses to tetanus toxoid. The results of this study demonstrate that MSCs from various tissues have similar immunophenotypes, in vitro immunosuppressive properties, and differentiation potential. </description>
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      <title>Interleukin-21: An interleukin-2 dependent player in rejection processes (Article)</title>
      <link>http://repub.eur.nl/res/pub/35392/</link>
      <pubDate>2007-06-01T00:00:00Z</pubDate>
      <description>BACKGROUND. Interleukin (IL)-21 is the most recently described cytokine that signals via the common cytokine receptor (γc), is produced by activated CD4+ T-cells, and regulates expansion and effector function of CD8+ T-cells. MATERIALS. To explore the actions of IL-21 with other γc-dependent cytokines in alloreactivity, mRNA expression of IL-21, IL-21R α-chain, and IL-2 proliferation and cytotoxicity was measured after stimulation in mixed lymphocyte reactions. Additionally, IL-21 and IL-21R α-chain expression was studied in biopsies of heart transplant patients. RESULTS. Analysis of mRNA expression levels of allostimulated T-cells showed a 10-fold induction of IL-21 and IL-21R α-chain. Interestingly, induction of IL-21 was highly dependent on IL-2 (as in the presence of anti-IL-2, anti-IL-2R α-chain, and the immunosuppressive drugs cyclosporine A, tacrolimus, and rapamycin) the transcription of IL-21 was almost completely inhibited, whereas in the presence of exogenous IL-2 the mRNA expression of IL-21 was even more upregulated. IL-21 functioned as a costimulator for IL-2 to augment proliferation and cytotoxic responses, while blockade of the IL-2 route abrogated these functions of IL-21. Blockade of the IL-21 route by anti-IL-21R α-chain monoclonal antibodies inhibited the proliferation of alloactivated T-cells. Also, in vivo alloreactivity was associated with IL-21/IL-21R α-chain expression. After heart transplantation, the highest intragraft IL-21, IL-21R α-chain, and IL-2 mRNA expression levels were measured during acute rejection (P&lt;0.001, P=0.01, P=0.03). CONCLUSION. IL-21 is a critical cytokine for IL-2 dependent immune processes. Blockade of the IL-21 pathway may provide a new perspective for the treatment of allogeneic responses in patients after transplantation. </description>
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      <title>Intragraft FOXP3 mRNA expression reflects antidonor immune reactivity in cardiac allograft patients (Article)</title>
      <link>http://repub.eur.nl/res/pub/35411/</link>
      <pubDate>2007-06-01T00:00:00Z</pubDate>
      <description>BACKGROUND. Regulatory FOXP3+ T cells control immune responses of effector T cells. However, whether these cells regulate antidonor responses in the graft of cardiac allograft patients is unknown. Therefore, we analyzed the gene expression profiles of regulatory and effector T-cell markers during immunological quiescence and acute rejection. METHODS. Quantitative real-time polymerase chain reaction was used to analyze mRNA expression levels in time-zero specimens (n=24) and endomyocardial biopsies (EMB; n=72) of cardiac allograft patients who remained free from rejection (nonrejectors; n=12) and patients with at least one histologically proven acute rejection episode (rejectors; International Society for Heart and Lung Transplantation [ISHLT] rejection grade &gt;2; n=12). RESULTS. For all analyzed regulatory and effector T-cell markers, mRNA expression levels were increased in biopsies taken after heart transplantation compared with those in time-zero specimens. Posttransplantation, the FOXP3 mRNA levels were higher in EMB assigned to a higher ISHLT rejection grade than the biopsies with grade 0: the highest mRNA levels were detected in the rejection biopsies (rejection grade &gt;2; P=0.003). In addition, the mRNA levels of CD25, glucocorticoid-induced TNF receptor family-related gene, cytotoxic T lymphocyte-associated antigen 4, interleukin-2, and granzyme B were also significantly higher in rejecting EMB than in nonrejecting EMB (rejection grade ≤2). This increase in expression levels in relation to the histological rejection grade was only observed in patients who developed an acute rejection episode; the mRNA levels of nonrejectors remained stable irrespective of ISHLT rejection grade. CONCLUSIONS. These observations suggest that, after clinical heart transplantation, FOXP3+ T cells do not prevent acute rejection, but rather are a response to antidonor effector T-cell activity. </description>
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      <title>Intragraft interleukin 2 mRNA expression during acute cellular rejection and left ventricular total wall thickness after heart transplantation (Article)</title>
      <link>http://repub.eur.nl/res/pub/8338/</link>
      <pubDate>2002-01-01T00:00:00Z</pubDate>
      <description>OBJECTIVE: To assess whether diastolic graft function is influenced by
      intragraft interleukin 2 (IL-2) messenger RNA (mRNA) expression in
      rejecting cardiac allografts. DESIGN: 16 recipients of cardiac allografts
      were monitored during the first three months after transplantation. The
      presence of IL-2 mRNA in endomyocardial biopsies (n = 123) was measured by
      reverse transcriptase polymerase chain reaction. To determine heart
      function, concurrent M mode and two dimensional Doppler echocardiograms
      were analysed. RESULTS: Histological signs of acute rejection
      (International Society for Heart and Lung Transplantation (ISHLT)
      rejection grade &gt; 2) were strongly associated with IL-2 mRNA expression
      (IL-2 mRNA was present in 12 of 20 endomyocardial biopsies (60%) with
      acute rejection and in 24 of 103 endomyocardial biopsies (23%) without
      acute rejection, p = 0.002). No significant relation was found between
      either histology or IL-2 mRNA expression alone and the studied
      echocardiographic parameters. However, stratification of the
      echocardiographic data into those of patients with and those without acute
      rejection showed that during acute rejection IL-2 mRNA expression was
      significantly associated with increased left ventricular total wall
      thickness (mean change in total wall thickness was +0.22 cm in patients
      with IL-2 mRNA expression versus -0.18 cm in patients without IL-2 mRNA
      expression, p = 0.048). CONCLUSIONS: An increase in left ventricular total
      wall thickness precedes IL-2 positive acute rejection after heart
      transplantation. Thus, cardiac allograft rejection accompanied by
      intragraft IL-2 mRNA expression may be indicative of more severe rejection
      episodes.</description>
    </item> <item>
      <title>Cardiac peptides differ in their response to exercise. Implications for patients with heart failure in clinical practice. (Article)</title>
      <link>http://repub.eur.nl/res/pub/12809/</link>
      <pubDate>1999-10-01T00:00:00Z</pubDate>
      <description>AIMS: Cardiac peptides have diagnostic and prognostic value in heart
          failure. Their plasma concentrations, however, are sensitive to rapid
          changes in haemodynamics. As blood sampling under standard conditions is
          not feasible in clinical practice, it is important to know which peptides
          are most resistant to change. Therefore, the present study investigated
          the differences in response to exercise between atrial natriuretic
          peptide, N-terminal proatrial natriuretic peptide, brain natriuretic
          peptide and the recently identified N-terminal probrain natriuretic
          peptide.METHODS and RESULTS: Fifty-two patients with chronic heart failure
          performed a symptom-limited graded bicycle exercise. Blood samples for
          determination of plasma concentrations of cardiac peptides were drawn at
          rest and at peak exercise. There was a significant difference in
          percentage increase in response to exercise between the four peptides
          (P&lt;0.0001). N-terminal proatrial natriuretic peptide increased less than
          atrial natriuretic peptide (5+/-18% vs 59+/-58%;P&lt;0.0001). The difference
          in increase between N-terminal probrain natriuretic peptide and brain
          natriuretic peptide was less distinct but still significant (24+/-24% vs
          38+/-52%, P&lt;0.05). CONCLUSIONS: Both N-terminal proatrial natriuretic
          peptide and N-terminal probrain natriuretic peptide increased less in
          response to exercise than their C-terminal counterparts. This implies that
          the circumstances under which blood sampling for measurements of
          N-terminal proatrial natriuretic peptide and N-terminal probrain
          natriuretic peptide should be performed are more favourable than the blood
          sampling conditions for atrial natriuretic peptide and brain natriuretic
          peptide.</description>
    </item> <item>
      <title>Relation of atrial natriuretic peptides to left ventricular systolic and diastolic function in heart failure (Article)</title>
      <link>http://repub.eur.nl/res/pub/5613/</link>
      <pubDate>1999-01-01T00:00:00Z</pubDate>
      <description>Background: Plasma concentrations of atrial natriuretic peptides are correlated with atrial pressures, as are left ventricular ejection fraction and left ventricular filling abnormalities.

Aims: This study investigated the relation of atrial natriuretic peptides to both left ventricular systolic and diastolic function in heart failure.

Methods: Plasma concentrations of atrial natriuretic peptide and N-terminal pro-atrial natriuretic peptide were measured in 63 patients with chronic heart failure and left ventricular systolic dysfunction. According to Doppler transmitral flow measurements, 19 patients had a restrictive and 44 patients had a non-restrictive left ventricular filling pattern.

Results: Plasma concentrations of atrial natriuretic peptide and N-terminal pro-atrial natriuretic peptide were higher in patients with a restrictive filling pattern than in patients with a non-restrictive filling pattern (197 vs. 75 pmol/l, P &lt; 0.0001 and 1.14 vs. 0.45 nmol/l, P &lt; 0.0001). In univariate analysis, atrial natriuretic peptide and N-terminal pro-atrial natriuretic peptide correlated with deceleration time, E/A ratio and left ventricular ejection fraction. In multivariate analysis, both peptides appeared independently related to left ventricular ejection fraction and left ventricular filling pattern.

Conclusion: In patients with chronic heart failure, atrial natriuretic peptides provide information on left ventricular systolic as well as diastolic function.</description>
    </item> <item>
      <title>The TNF-alpha system in heart failure and after heart transplantation: plasma protein levels, mRNA expression, soluble receptors and plasma buffer capacity (Article)</title>
      <link>http://repub.eur.nl/res/pub/9102/</link>
      <pubDate>1999-01-01T00:00:00Z</pubDate>
      <description>BACKGROUND: The two soluble tumour necrosis factor (TNF) receptors
          (sTNF-R1, sTNF-R2) can bind TNF-alpha, which is a cytokine with
          cardiodepressant properties. In heart failure and after heart
          transplantation, the TNF-alpha system is unbalanced, due to elevated
          levels of sTNF receptors. AIM: To assess the activity of the TNF-alpha
          system in patients with heart failure and after heart transplantation.
          METHODS: We measured TNF-alpha mRNA expression of peripheral blood
          mononuclear cells, plasma levels of TNF-alpha and sTNF reverse
          transcriptase receptors, using polymerase chain reaction and ELISA and
          performed a TNF-alpha binding capacity analysis, quantitating the buffer
          capacity of patients' plasma. RESULTS: In 11 patients with heart failure
          and in 15 cardiac allograft recipients, the TNF-alpha mRNA expression was
          comparable to controls. This level of mRNA was not accompanied by
          detectable TNF-alpha plasma levels. Significantly higher sTNF receptors
          levels were found in patients: ( P &lt;0.001; ANOVA). The TNF-alpha binding
          capacity of patients' plasma was significantly increased, which led to
          decreased TNF-alpha recovery ( P&lt;0.05). Both sTNF receptors showed a
          linear correlation with serum creatinine (sTNF-RI: r=0.92; sTNF-R2:
          r=0.82, P&lt;0.001). CONCLUSIONS:The TNF-alpha mRNA expression and plasma
          levels show that the 'peripheral' TNF-alpha system is not activated. The
          high sTNF-receptors levels and their elevated TNF-alpha binding capacity,
          resulting in decreased TNF-alpha bioavailability, may contribute to an
          immunosuppressed state in these patients.</description>
    </item> <item>
      <title>Renal insufficiency after heart transplantation: a case-control study (Article)</title>
      <link>http://repub.eur.nl/res/pub/8912/</link>
      <pubDate>1998-01-01T00:00:00Z</pubDate>
      <description>BACKGROUND: In Rotterdam 304 heart transplants have been performed since
          1984. End-stage renal failure, necessitating renal replacement therapy,
          has developed in 24 patients (8%) after an interval of 25-121 months
          (median 79 months). After starting renal replacement therapy one-year
          survival was only 60%. Overall survival after heart transplantation,
          however, was favourable: 5 and 10 year survival rates of 79% and 50%
          respectively. METHODS: A case-control study was performed to identify
          possible risk factors in cases who went on to develop end-stage renal
          failure compared to controls. RESULTS: We found that renal failure was not
          limited to elderly patients with ischaemic heart disease, but also
          occurred in young patients having dilated cardiomyopathy. A significant
          rise in the serum creatinine was found in cases compared to controls as
          early as 3 months after transplantation. Cyclosporin dose and trough
          levels were not different between cases and controls. Neither were there
          differences in the use of calcium-antagonists or other antihypertensive
          drugs, allopurinol or diuretics. Rejection incidence was also similar
          between the two groups. CONCLUSIONS: Renal failure after heart
          transplantation is a long term complication of cyclosporin use that is not
          limited to elderly patients with ischaemic heart disease. Cyclosporin dose
          and trough levels in the cases were not different from patients
          maintaining stable good renal function, indicating that cyclosporin
          nephrotoxicity is the result of an individually determined susceptibility
          to cyclosporin. Suggestions for future strategies to prevent renal failure
          are given.</description>
    </item> <item>
      <title>Patient to patient hepatitis B transmission during heart biopsy procedures. A report of a European Working Party on Viral Hepatitis in Heart Transplant Recipients. (Article)</title>
      <link>http://repub.eur.nl/res/pub/3589/</link>
      <pubDate>1996-01-01T00:00:00Z</pubDate>
      <description>Letter</description>
    </item> <item>
      <title>Clinical aspects of heart transplantation  (Doctoral Thesis)</title>
      <link>http://repub.eur.nl/res/pub/39352/</link>
      <pubDate>1993-10-06T00:00:00Z</pubDate>
      <description>The aim of this thesis is to describe the continued efforts to optimize
patient care by ongoing analysis of various problems which currently
predominate in bean transplantation. Chapters l-ID describe our research in
heart transplant candidates and in subsequent chapters specific problems of the
transplant recipient are addressed. Attempts to reduce the incidence of rejection
are described in Chapters IV and V. The problems of coronaty vascular disease
in the allograft and the angiographic findings in our patients are summarized
in Chapters VI, VII and VID. The complications of immunosuppressive
therapy are subject of Chapters IX, X and XI.Finally, the results in the first
200 heart transplant recipients of the Rotterdam Hea.rt Transplant Program are
presented in Chapter XII.</description>
    </item> <item>
      <title>Percutaneous directional atherectomy for discrete coronary lesions in cardiac transplant patients (Article)</title>
      <link>http://repub.eur.nl/res/pub/4467/</link>
      <pubDate>1992-01-01T00:00:00Z</pubDate>
      <description></description>
    </item> <item>
      <title>Too early for cardiac transplantation-the right decision? (Article)</title>
      <link>http://repub.eur.nl/res/pub/5418/</link>
      <pubDate>1992-01-01T00:00:00Z</pubDate>
      <description>In 109 out of 479 patients who were referred for cardiac transplantation it was considered to be too early to put them on the waiting list for a donor heart. The clinical course of these 109 patients was analysed in order to verify whether this decision had been right. The mean age of the patients was 43 years, half of them suffered from ischaemic heart disease. The systolic left ventricular function of the patients was severely depressed (mean left ventricular ejection fraction 21%) and the left ventricular cavity was markedly dilated (mean echocardiographic end diastolic dimension 73 mm). Functional capacity, measured by bicycle ergometry, was low: mean maximal workload 62% of the expected load for gender, height and age. The median follow-up duration was 31 months. The survival rate of the patients was better than that of 175 patients who were accepted for transplantation after referral, 92%, 87%, 81%, 71% and 73%, 73%, 71%, 68% after 1, 2, 3 and 4 years respectively. Re-assessment was necessary in 29% of the patients within 1 year and in 52% within 3 years. Twenty patients died: 12 patients died before re-assessment had been initiated (eight sudden deaths), six patients because of progressive heart failure before heart transplantation could be performed and two patients died after heart transplantation. Left ventricular ejection fraction, pulmonary capillary wedge pressure and transpulmonary gradient were not reliable predictors of the course of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)</description>
    </item> <item>
      <title>Changes in left ventricular function and wall thickness in heart transplant recipients and their relation to acute rejection: an assessment by digitised M mode echocardiography (Article)</title>
      <link>http://repub.eur.nl/res/pub/5443/</link>
      <pubDate>1992-01-01T00:00:00Z</pubDate>
      <description>OBJECTIVE--Assessment of changes in left ventricular diastolic function and wall thickness after heart transplantation to verify whether these changes predicted acute rejection assessed by endomyocardial biopsy. DESIGN--Follow up according to a predefined protocol of consecutive patients from the first week after transplantation. SETTING--Heart transplantation unit of the Thoraxcentre, University Hospital Rotterdam Dijkzigt, The Netherlands. PATIENTS--All 32 patients undergoing orthotopic heart transplantation from 1 January 1989 to 31 March 1990 were examined. Two were excluded from the analysis. Patients were treated with cyclosporin and low dose steroids. MAIN OUTCOME MEASURES--Data obtained by digitised M mode echocardiography were compared with the results of endomyocardial biopsy (Billingham classification). Mean values for left ventricular wall thickness, internal dimension, and their standardised rates of change and fractional shortening were determined from 4-6 consecutive expiratory beats. Mean values and individual trends during follow up were also investigated for each ultrasound variable. The results of these average values were compared with values in a group of 10 healthy volunteers. RESULTS--Median follow-up was 177 days (range 10-399). Two hundred and sixty three consecutive M mode studies were examined in relation to concurrent biopsy results. No significant differences were observed between the ultrasound variables at the time of moderate acute rejection (Billingham class 2, n = 37) and other biopsy classes (n = 226). Nor did changes in individual patients predict (moderate) acute rejection episodes. Twenty six of the 30 patients had an abnormal (slow) left ventricular relaxation pattern throughout follow up. CONCLUSIONS--Digitised left ventricular M mode echocardiography did not predict the presence of acute rejection. In most patients there was a persistent slow left ventricular relaxation pattern.</description>
    </item> <item>
      <title>Harttransplantatie, waarom hij niet? (Article)</title>
      <link>http://repub.eur.nl/res/pub/5395/</link>
      <pubDate>1989-01-01T00:00:00Z</pubDate>
      <description></description>
    </item> <item>
      <title>Treatment with cyclosporin and risks of graft rejection in male kidney and heart transplant recipients with non-O blood (Article)</title>
      <link>http://repub.eur.nl/res/pub/5380/</link>
      <pubDate>1988-01-01T00:00:00Z</pubDate>
      <description>In a consecutive series of 146 kidney transplant recipients treated with cyclosporin A a strong correlation between matching for the HLA-A, HLA-B, and HLA-DR loci specificities and outcome of the grafts was observed in male recipients with non-O blood groups. Such a beneficial effect of matching was not found in female patients or male patients with blood group O. In these patients survival of the grafts at one year was good irrespective of the number of HLA-A, B, and DR mismatches. Also in 47 male heart transplant recipients immune responsiveness against mismatched HLA antigens was related to blood group. A significantly higher incidence of rejection episodes was observed in male patients with non-O blood groups (n = 32) than in those with blood group O (n = 15). Matching for HLA-DR reduced the number of acute rejection episodes in male patients with non-O blood. These findings may help explain the controversial reports about the importance of HLA matching in organ transplantation. Furthermore, as most candidates for heart transplantation are male and not of blood group O, the higher incidence of graft rejection in these patients underscores the need for an exchange strategy of donor hearts.</description>
    </item> <item>
      <title>The prophylactic use of Orthoclone OKT3 in kidney and heart transplantation (Article)</title>
      <link>http://repub.eur.nl/res/pub/5477/</link>
      <pubDate>1988-01-01T00:00:00Z</pubDate>
      <description></description>
    </item>
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