Daniel Kretzschmar

Recruitment of circulating dendritic cell precursors into the infarcted myocardium and pro-inflammatory response in acute myocardial infarction.

DC (dendritic cells) play an important role in the immune system. They invade peripheral tissues to detect harmful antigens, inducing a local immune response. Studies suggest that DCPs (dendritic cell precursors) might be reduced in AMI (acute myocardial infarction); however, the reason for their reduction is unknown yet. In the present study, circulating mDCPs (myeloid DCPs), pDCPs (plasmacytoid DCPs), tDCPs (total DCPs) and serum levels of TNFα (tumour necrosis factor α), IL (interleukin)-2, -4, -5, -6, -10 and -12 were analysed by flow cytometry in blood of patients with NSTEMI [non-STEMI (ST-segment elevation myocardial infarction)] (n=44) and STEMI (n=34) compared with controls with excluded CAD (coronary artery disease) (n=45). Post-mortem myocardial specimens of patients with AMI (n=12) and healthy myocardium of accident victims (n=10) were immunostained for mDCs (myeloid dendritic cells) T-cells and macrophages. Compared with controls, in patients with AMI a significant decrease in circulating mDCPs, pDCPs and tDCPs was observed (each P<0.0001). The extent of the decrease was higher in STEMI than NSTEMI patients. Serum levels were significantly higher in patients with AMI compared with controls for IL-6, -10, -12 and TNFα (each P<0.03). Immunostaining revealed significantly higher number of DCs, T-cells and macrophages (each P<0.002) in infarcted than control myocardium. We show that circulating DCPs are significantly reduced in AMI, with a pronounced reduction in STEMI patients. This was accompanied by a significant increase of inflammatory serum cytokines in patients with AMI. Immunohistochemical analysis unravelled that the reduction of circulating DCPs might be due to recruitment into the infarcted myocardium.

Decreased Regulatory T Cells in Vulnerable Atherosclerotic Lesions: Imbalance between Pro- and Anti-Inflammatory Cells in Atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the arterial wall in which presentation of autoantigens by dendritic cells (DCs) leads to the activation of T cells. Anti-inflammatory cells like Tregs counterbalance inflammation in atherogenesis. In our study, human carotid plaque specimens were classified as stable (14) and unstable (15) according to established morphological criteria. Vessel specimens (n = 12) without any signs of atherosclerosis were used as controls. Immunohistochemical staining was performed to detect different types of DCs (S100, fascin, CD83, CD209, CD304, and CD123), proinflammatory T cells (CD3, CD4, CD8, and CD161), and anti-inflammatory Tregs (FoxP3). The following results were observed: in unstable lesions, significantly higher numbers of proinflammatory cells like DCs, T helper cells, cytotoxic T cells, and natural killer cells were detected compared to stable plaques. Additionally, there was a significantly higher expression of HLA-DR and more T cell activation (CD25, CD69) in unstable lesions. On the contrary, unstable lesions contained significantly lower numbers of Tregs. Furthermore, a significant inverse correlation between myeloid DCs and Tregs was shown. These data suggest an increased inflammatory state in vulnerable plaques resulting from an imbalance of the frequency of local pro- and anti-inflammatory immune cells.

Decrease in dendritic cells in endomyocardial biopsies of human dilated cardiomyopathy

Dendritic cells (DCs) are sentinels of the immune system—their role in myocardial disease is unknown as yet. We investigated their myocardial presence in human dilated cardiomyopathy (DCM).

Circulating dendritic cell precursors in chronic kidney disease: a cross-sectional study

BackgroundDendritic cells (DC) are professional antigen-presenting cells in the immune system. They patrol the blood as circulating dendritic cell precursors (DCP). Decreased blood DCP count has been shown to be related to atherosclerotic plaque burden. Since chronic kidney disease (CKD) is associated with chronic inflammation and increased cardiovascular risk, the aim of our study was to investigate a potential effect of CKD on circulating DCP numbers especially in patients with a history of cardiovascular disease.MethodsThe number of circulating myeloid (mDCP), plasmacytoid (pDCP), and total DCP (tDCP) was analysed by flow cytometry in 245 patients with CKD stage 3 (with and without known cardiovascular events) and 85 coronary healthy controls. In addition, data were compared with a historical group of 130 patients with known coronary artery disease (CAD).ResultsCompared to controls, patients with CKD 3 revealed a significant decrease in circulating mDCP (-29%), pDCP (-43%), and tDCP (-38%) (P < 0.001, respectively). Compared with CAD-patients, the decrease in circulating DCP in CKD was comparable or even more pronounced indicating a potential role for DCP in cardiovascular risk potentiation due to CKD.ConclusionsBased on previous findings in CAD, the marked decrease of DCP in CKD implicates a potential role for DCP as a mediator of cardiovascular disease. Whether DCP in CKD may act as new cardiovascular biomarkers needs to be established in future prospective trials.

Multibiomarker analysis in patients with acute myocardial infarction

Novel biomarkers representing different pathobiological pathways and their role in patients with acute myocardial infarction (AMI) were studied.

A comparative analysis of novel cardiovascular biomarkers in patients with chronic heart failure

BACKGROUND Heart failure (HF) with reduced ejection fraction remains a major therapeutic challenge. The aim of this study was to investigate the role of novel cardiovascular biomarkers, i.e. soluble suppression of tumorigenicity (sST2), growth-differentiation factor-15 (GDF-15), soluble urokinase plasminogen activator receptor (suPAR) and heart-type fatty acid binding protein (H-FABP) in patients with ischaemic (ICM) or dilative cardiomyopathy (DCM). MATERIALS AND METHODS A total of 200 patients were enrolled in this study: 65 were diagnosed with DCM and 59 patients suffering from ICM were included. 76 patients without coronary artery disease or signs of heart failure were included as controls. Plasma samples of all patients were analyzed by use of ELISA. RESULTS Levels of sST2, suPAR and H-FABP were significantly higher in ICM and DCM patients compared to the control group (p<0.0001). However, there were no significant differences between ICM and DCM in biomarker levels. Ejection fraction correlated inversely with cardiac biomarkers (sST2 p<0.0001, GDF-15 p=0.0394, suPAR p=0.0029, H-FABP p<0.0001). Similarly, CRP levels also showed a positive correlation with cardiac biomarkers. Renal insufficiency (p<0.0001) and diabetes (sST2 p=0.0021, GDF-15 p=0.0055, suPAR p=0.0339, H-FABP p=0.0010) were significantly associated with a rise in cardiac biomarkers. CONCLUSION Novel cardiovascular biomarkers such as ST2, GDF-15, uPAR and H-FABP could offer a great potential for more precise diagnostic in ICM and DCM patients. H-FABP was the most promising marker in our study, followed by sST2, uPAR and GDF-15. Additional prospective studies will be necessary to further evaluate the potential clinical benefits in routine treatment of HF.

Decrease in circulating dendritic cell precursors in patients with peripheral artery disease.

Peripheral artery disease (PAD) is a common manifestation of atherosclerosis. Inflammation is important for initiation and progression of the disease. Dendritic cells (DCs) as antigen-presenting cells play an important role in the immune system. Therefore, we hypothesize that, in patients with PAD, DCPs might be reduced in blood due to their recruitment into the vascular wall and induce a proinflammatory response. The numbers of myeloid DCPs, plasmacytoid DCPs, and total DCPs were analyzed by flow cytometry in blood of patients with PAD (n = 52) compared to controls (n = 60). Femoralis plaques (n = 12) of patients who underwent surgery were immunostained for CD209 and CD83 (mDCs) as well as CD304, CD123 (pDCs), and HLA-DR. In patients with PAD, a significant decrease in mDCPs, pDCPs, and tDCPs was observed. In immunostaining, markers indicative for mDCs (CD209: 16 versus 8 cells/0.1 mm2, P = 0.02; CD83: 19 versus 5 cells/0.1 mm2, P = 0.03) were significantly elevated in femoralis plaques compared to control vessels. We show for the first time that mDCPs, pDCPs, and tDCPs are significantly reduced in patients with PAD. Immunohistochemical analysis unraveled that the decrease in DCPs might be due to their recruitment into atherosclerotic plaques.

Impact of Ivabradine on Inflammatory Markers in Chronic Heart Failure

Background. Inflammation plays a crucial role in the progression of chronic heart failure (CHF). Ivabradine is known to reduce the morbidity and mortality of patients with CHF under certain conditions. Beyond the reduction of heart rate, only limited knowledge exists about potential anti-inflammatory effects of ivabradine that might contribute to its benefit in CHF. Thus, the present study aimed to investigate the effect of ivabradine on systemic inflammation. Methods. In the present study, 33 patients with CHF due to dilated, ischemic, and hypertensive cardiomyopathy were treated with ivabradine according to the guidelines of the European Society of Cardiology (ESC). A number of circulating dendritic cells as well as inflammatory mediators were investigated using FACS analysis and ELISA, respectively, before and during ivabradine therapy. Results. Treatment with ivabradine resulted in a significant improvement of CHF symptoms as well as an increase in left ventricular ejection fraction. Moreover, ivabradine treatment led to a significant reduction of TNF-alpha (TNF-α) serum levels and a reconstitution of circulating dendritic cells which are known to be reduced in patients with CHF. Conclusion. We show that treatment with ivabradine in patients with CHF resulted in an improvement of HF symptoms and ejection fraction as well as a normalization of inflammatory mediators.

In vitro evaluation of a novel pulsatile right heart assist device - the PERKAT system

Purpose Acute right ventricular failure is a life-threatening condition with poor prognosis. It occurs as a result of right ventricular infarction, postcardiac transplantation, or postimplantation of a left ventricular assist device. Temporary mechanical right ventricular support could be a reasonable treatment option. Therefore, we developed a novel percutaneously implantable device. Methods The PERKAT device consists of a self-expandable chamber covered with multiple inflow valves carrying foils. A flexible outlet tube with a pigtail tip is attached to the distal end. PERKAT is designed for percutaneous implantation through the femoral vein (18 French sheath). The chamber is expanded in the inferior vena cava while the outlet tube bypasses the right heart and the pigtail tip is lying in the pulmonary trunk. An IABP balloon is inserted into the chamber and connected to an IABP console. Balloon deflation generates blood flow from the vena cava into the chamber through the foil valves. During inflation blood is pumped through the tube into the pulmonary arteries. Results In vitro experiments were performed using 30 mL and 40 mL IABP balloons. IABP inflation/deflation times were set to 80, 90, 100, and 110 per min with an afterload of 22 mmHg and 44 mmHg. PERKAT generated flow rates between 1.6 to 3.1 l/min, depending on balloon size, pump cycle, and afterload. Conclusions The novel percutaneously implantable right ventricular assist device offers emergency support of up to 3 l/min. Based on the successful in vitro evaluation, we recommend the system as a promising approach for treatment of patients in need of RV support.

Schwerste thrombotisch-thrombozytopenische Purpura (TTP) nach H1N1-Vakzinierung

ZusammenfassungHintergrund:Die thrombotisch-thrombozytopenische Purpura (TTP) ist ein schweres Krankheitsbild mit Mikrothromben in verschiedenen Organen. Die idiopathische Form der TTP ist durch eine verminderte Aktivität der Proteinase ADAMTS13 und durch das Vorhandensein von Autoantikörpern gegen ADAMTS13 gekennzeichnet. Über die Induktion dieser Autoantikörper ist bisher wenig bekannt. Bestimmte Medikamente können über einen Haptenmechanismus die Bildung von Anti-ADAMTS13-Antikörpern initiieren.Fallbeschreibung:Ein 56-jähriger Patient wurde aufgrund einer Verschlechterung des Allgemeinzustands mit hämolytischer Anämie (Hämoglobin 4,17 mmol/l, Hämatokrit 0,19) und Thrombopenie (22 Gpt/l) unklarer Genese aus einem auswärtigen Krankenhaus übernommen. Laborchemisch bestand zusätzlich eine erhöhte Lactatdehydrogenase (45,37 μmol/l/s). 13 Tage vor der stationären Aufnahme des Patienten war eine H1N1-Vakzinierung vorgenommen worden.In den ersten Stunden nach Aufnahme entwickelte sich eine zunehmende Verwirrtheit mit rezidivierenden Krampfanfällen. Laborbefunde zeigten ein erhöhtes Gesamtbilirubin (126 μmol/l) und ein erniedrigtes Haptoglobin (< 0,08 g/l). Im Blutausstrich lagen 24% Fragmentozyten vor. Der direkte und indirekte Coombs-Test waren negativ.Die Diagnose einer TTP wurde klinisch und anhand des Nachweises von ADAMTS13-Antikörpern gestellt. Trotz initial täglicher Plasmaseparationen gegen Frischplasma und Kortikosteroidtherapie kam es zunächst zu keinem adäquaten Anstieg der Thrombozyten und zu keiner Regredienz der Hämolyseparameter, so dass die Immunsuppression um die insgesamt viermalige Gabe von 375 mg/m2 Körperoberfläche Rituximab im Abstand von jeweils 7 Tagen erweitert wurde. Im zeitlichen Verlauf von 5 Wochen kam es zu einem Anstieg und einer Stabilisation der Thrombozytenzahlen. Im weiteren Verlauf konnten die Plasmapheresetherapien nach insgesamt 46-maliger Durchführung und erzielter kompletter Remission beendet werden.Schlussfolgerung:Als potentieller ätiologischer Faktor für die Pathogenese einer TTP ist eine H1N1-Vakzinierung zu diskutieren, aber letztendlich nicht bewiesen, da Seren vor Impfung nicht untersucht werden konnten. Der zusätzliche Einsatz von Rituximab zur Standardtherapie durch Plasmapherese und Kortikosteroide ist bei Patienten mit schwersten autoantikörpervermittelten Verläufen einer TTP effektiv.AbstractBackground:Thrombotic thrombocytopenic purpura (TTP) is a severe disease with microthrombi in various organs. The idopathic subtype is characterized by reduced ADAMTS13 activity mediated via autoantibodies against this protease. Induction of autoantibodies mechanistically is incompletely understood, but certain drugs can induce anti-ADAMTS13 antibodies through hapten mechanisms.Case Report:A 56-year-old man was admitted from an external hospital because of a rapidly worsening general condition, hemolytic anemia (hemoglobin 4.17 mmol/l, hematocrit 0.19), and thrombocytopenia (22 Gpt/l) for unknown reasons. Additionally, he was found to have an elevated lactate dehydrogenase (45.37 μmol/l/s). 13 days before hospitalization he had received vaccination against H1N1.Laboratory tests revealed an increased total bilirubin (126 μmol/l), and a decreased haptoglobin level (< 0.08 g/l). The blood smear showed 24% fragmentocytes. Direct and indirect Coombs test were negative.TPP was diagnosed based on the clinical presentation and the detection of ADAMTS13 antibodies. Despite daily plasma exchange via plasmapheresis and administration of corticosteroids, there was no significant rise in platelet counts. Immunosuppression with a total of four weekly doses of rituximab (375 mg/m2 body surface area) was added. Over the next 5 weeks, the platelet count very slowly rose. After a total of 46 sessions, plasmapheresis was ended with complete remission of the disease.Conclusion:This report emphasizes the immunologic susceptibility of TTP, and suggests the potential, but not proven role of H1N1 vaccination in the pathogenesis of TTP, because no serum before vaccination was available. Severe autoantibody TTP can be successfully treated by administering rituximab in addition to standard treatment with plasmapheresis and corticosteroids.BACKGROUND Thrombotic thrombocytopenic purpura (TTP) is a severe disease with microthrombi in various organs. The idopathic subtype is characterized by reduced ADAMTS13 activity mediated via autoantibodies against this protease. Induction of autoantibodies mechanistically is incompletely understood, but certain drugs can induce anti-ADAMTS13 antibodies through hapten mechanisms. CASE REPORT A 56-year-old man was admitted from an external hospital because of a rapidly worsening general condition, hemolytic anemia (hemoglobin 4.17 mmol/l, hematocrit 0.19), and thrombocytopenia (22 Gpt/l) for unknown reasons. Additionally, he was found to have an elevated lactate dehydrogenase (45.37 μmol/l/s). 13 days before hospitalization he had received vaccination against H1N1. Laboratory tests revealed an increased total bilirubin (126 μmol/l), and a decreased haptoglobin level (< 0.08 g/l). The blood smear showed 24% fragmentocytes. Direct and indirect Coombs test were negative. TPP was diagnosed based on the clinical presentation and the detection of ADAMTS13 antibodies. Despite daily plasma exchange via plasmapheresis and administration of corticosteroids, there was no significant rise in platelet counts. Immunosuppression with a total of four weekly doses of rituximab (375 mg/m(2) body surface area) was added. Over the next 5 weeks, the platelet count very slowly rose. After a total of 46 sessions, plasmapheresis was ended with complete remission of the disease. CONCLUSION This report emphasizes the immunologic susceptibility of TTP, and suggests the potential, but not proven role of H1N1 vaccination in the pathogenesis of TTP, because no serum before vaccination was available. Severe autoantibody TTP can be successfully treated by administering rituximab in addition to standard treatment with plasmapheresis and corticosteroids.