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BACKGROUND: Cardiac hypertrophy is characterized by remodeling of the myocardium, which involves alterations in the ECM (extracellular matrix) and cardiomyocyte structure. These alterations critically contribute to impaired contractility and relaxation, ultimately leading to heart failure. Emerging evidence implicates that extracellular signaling molecules are critically involved in the pathogenesis of cardiac hypertrophy and remodeling. The immunophilin CyPA (cyclophilin A) has been identified as a potential culprit. In this study, we aimed to unravel the interplay between eCyPA (extracellular CyPA) and myocardial dysfunction and evaluate the therapeutic potential of inhibiting its extracellular accumulation to improve heart function. METHODS: Employing a multidisciplinary approach encompassing in silico, in vitro, in vivo, and ex vivo experiments we studied a mouse model of cardiac hypertrophy and human heart specimen to decipher the interaction of CyPA and the cardiac microenvironment in highly relevant pre-/clinical settings. Myocardial expression of CyPA (immunohistology) and the inflammatory transcriptome (NanoString) was analyzed in human cardiac tissue derived from patients with nonischemic, noninflammatory congestive heart failure (n=187). These analyses were paralleled by a mouse model of Ang (angiotensin) II-induced heart failure, which was assessed by functional (echocardiography), structural (immunohistology, atomic force microscopy), and biomolecular (Raman spectroscopy) analyses. The effect of inhibiting eCyPA in the cardiac microenvironment was evaluated using a newly developed neutralizing anti-eCyPA monoclonal antibody. RESULTS: We observed a significant accumulation of eCyPA in both human and murine-failing hearts. Importantly, higher eCyPA expression was associated with poor clinical outcomes in patients (P=0.043) and contractile dysfunction in mice (Pearson correlation coefficient, -0.73). Further, myocardial expression of eCyPA was critically associated with an increase in myocardial hypertrophy, inflammation, fibrosis, stiffness, and cardiac dysfunction in vivo. Antibody-based inhibition of eCyPA prevented (Ang II)-induced myocardial remodeling and dysfunction in mice. CONCLUSIONS: Our study provides strong evidence of the pathogenic role of eCyPA in remodeling, myocardial stiffening, and dysfunction in heart failure. The findings suggest that antibody-based inhibition of eCyPA may offer a novel therapeutic strategy for nonischemic heart failure. Further research is needed to evaluate the translational potential of these interventions in human patients with cardiac hypertrophy.
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Cyclophilin A (CyPA) is widely expressed by all prokaryotic and eukaryotic cells. Upon activation, CyPA can be released into the extracellular space to engage in a variety of functions, such as interaction with the CD147 receptor, that contribute to the pathogenesis of cardiovascular diseases. CyPA was recently found to undergo acetylation at K82 and K125, two lysine residues conserved in most species, and these modifications are required for secretion of CyPA in response to cell activation in vascular smooth muscle cells. Herein we addressed whether acetylation at these sites is also required for the release of CyPA from platelets based on the potential for local delivery of CyPA that may exacerbate cardiovascular disease events. Western blot analyses confirmed the presence of CyPA in human and mouse platelets. Thrombin stimulation resulted in CyPA release from platelets; however, no acetylation was observed-neither in cell lysates nor in supernatants of both untreated and activated platelets, nor after immunoprecipitation of CyPA from platelets. Shotgun proteomics detected two CyPA peptide precursors in the recombinant protein, acetylated at K28, but again, no acetylation was found in CyPA derived from resting or stimulated platelets. Our findings suggest that acetylation of CyPA is not a major protein modification in platelets and that CyPA acetylation is not required for its secretion from platelets.
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Plaquetas/metabolismo , Ciclofilina A/metabolismo , Ativação Plaquetária , Acetilação , Animais , Humanos , Lisina , CamundongosRESUMO
BACKGROUND/AIMS: Tachycardiomyopathy (TCM) is a largely reversible form of non-ischemic heart failure. The underlying mechanism are, however, still today poorly understood. Recent data indicate distinct changes in mitochondrial distribution in these patients, compared to other non-ischemic cardiomyopathies.This study investigated underlying mechanisms in mitochondrial dynamics in endomyocardial biopsy samples (EMB) from patients with TCM and compared them to patients with dilated cardiomyopathy (DCM), which show similar clinical features. METHODS: Focused mRNA analyses were performed on routinely obtained paraffinfixed EMB specimen from patients fulfilling TCM diagnosis criteria, as well as patients with DCM to elucidate regulatory changes in mitochondrial fusion, fission and mitophagy. RESULTS: In patients with TCM we were able to identify mRNA of Mitofusin 1 and 2, two effector proteins regulating mitochondrial fusion, to be strongly upregulated compared to patients with DCM. Conclusively, we did not find differences in the mRNA expression of mitochondrial fission regulators including DRP1, Fis1, MFF, MiD49, and MiD51. Furthermore, we did not find significant changes in PINK1 expression, an important mediator for mitochondrial autophagy. CONCLUSION: The mRNA upregulation of Mitofusin 1 and 2 provides first insight into the complex changes of mitochondrial dynamics in cardiomyocytes of patients with reversible heart failure due to TCM.
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Cardiomiopatia Dilatada/genética , GTP Fosfo-Hidrolases/genética , Mitocôndrias/genética , Dinâmica Mitocondrial/genética , Proteínas de Transporte da Membrana Mitocondrial/genética , Proteínas Mitocondriais/genética , RNA Mensageiro/genética , Biópsia , Cardiomiopatia Dilatada/classificação , Cardiomiopatia Dilatada/diagnóstico , Cardiomiopatia Dilatada/fisiopatologia , Dinaminas , GTP Fosfo-Hidrolases/metabolismo , Regulação da Expressão Gênica , Frequência Cardíaca/fisiologia , Humanos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Proteínas Mitocondriais/metabolismo , Mitofagia/genética , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Fatores de Alongamento de Peptídeos/genética , Fatores de Alongamento de Peptídeos/metabolismo , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , RNA Mensageiro/metabolismoRESUMO
INTRODUCTION: The role of cryoballoon (CB) pulmonary vein isolation (PVI) for patients with persistent atrial fibrillation (AF) is controversial, since long-term success can be poor. We performed left atrial voltage mapping before CB PVI and determined AF-free survival depending on the extent of low-voltage areas (LVAs). METHODS AND RESULTS: We consecutively enrolled 60 patients with persistent AF (average age, 60.6 ± 12.9 years; CHA2 DS 2 VASc score, 2.3 ± 1.6; and left atrial size 46.0 ± 5.2 mm) who were planned for CB PVI. Before ablation, we performed left atrial voltage mapping (Abbott EnSite Precision or Velocity). LVAs were defined if local bipolar signal amplitudes were less than 0.5 mV during sinus rhythm. Thirty-seven patients did not show significant LVAs (<10%), while 12 patients had LVAs between 10% and 30% and 11 patients showed substantial LVAs greater than 30% of the left atrial area. CB PVI could be successfully performed in all patients. A 7-day holter monitoring was obtained 3, 6, and 12 months after ablation. After a 12-month follow-up time, 83.8% of patients without LVAs (<10%) were free of atrial fibrillation, while 50.0% of patients with 10% to 30% LVAs and 9.1% of patients with LVAs more than 30% had stable sinus rhythm. The degree of atrial fibrosis correlated with the risk of AF recurrence. CONCLUSION: In patients with persistent AF undergoing CB PVI, the extent of left atrial LVAs predicts an AF-free survival. CB PVI seems to be a highly effective treatment for patients with persistent AF without atrial fibrosis.
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Fibrilação Atrial/terapia , Criocirurgia , Veias Pulmonares/cirurgia , Potenciais de Ação , Idoso , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/fisiopatologia , Função do Átrio Esquerdo , Remodelamento Atrial , Criocirurgia/efeitos adversos , Técnicas Eletrofisiológicas Cardíacas , Feminino , Fibrose , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Intervalo Livre de Progressão , Veias Pulmonares/fisiopatologia , Recidiva , Fatores de Risco , Fatores de TempoRESUMO
BACKGROUND/AIMS: Fibrotic remodeling of the atria plays a key role in the pathogenesis of atrial fibrillation (AF). As little is known about the contribution of circulating monocytes in atrial remodeling and the pathophysiology of AF, we investigated profibrotic factors in different subsets of circulating monocytes obtained from patients with atrial fibrillation undergoing catheter ablation. METHODS: A 3D high density voltage mapping was performed in sinus rhythm to evaluate the extent of low-voltage areas (LVAs) in the atria of 71 patients with persistent AF. Low-voltage was defined as signals of < 0.5mV during sinus rhythm. Prior to ablation, blood was drawn and monocytes were analyzed by FACS. Based on the expression of CD14 and CD16, three subgroups including CD14++ CD16- ('classical'), CD14++ CD16+ ('intermediate'), and CD14+ CD16++ ('non-classical') were analyzed for the expression of TGFb, CD147, and MMP-9, representing pivotal profibrotic pathways in myocardial remodeling. RESULTS: Expression of TGFb was increased in CD14+ monocytes of patients with extensive LVAs compared to patients with a low extend of LVAs. While CD14++ CD16- monocytes showed no difference, CD14++ CD16+ and CD14+ CD16++ monocytes showed a strong increase of TGFb abundance. Although CD147 and MMP-9 are strongly associated with myocardial fibrosis, we found no difference in expression between the two groups in any monocyte subsets. CONCLUSION: TGFb is specifically upregulated on CD14++ CD16+ and CD14+ CD16++ monocytes in patients with extensive LVAs undergoing catheter ablation.
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Fibrilação Atrial/patologia , Receptores de Lipopolissacarídeos/metabolismo , Monócitos/metabolismo , Receptores de IgG/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Idoso , Fibrilação Atrial/imunologia , Basigina/metabolismo , Fenômenos Eletrofisiológicos , Feminino , Fibrose , Átrios do Coração/fisiopatologia , Humanos , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Pessoa de Meia-Idade , Monócitos/citologia , Regulação para CimaRESUMO
BACKGROUND/AIMS: The polyamine oxidase inhibitor MDL-72527 (N1,N4-bis(2,3-butadienyl)-1,4-butanediamine) were expected to increase the abundance of spermine, a powerful inhibitor of platelet activation. Nothing is known, however, on the sensitivity of platelet function and survival to MDL-72527 exposure. The present study thus explored whether MDL-72527 modifies function and survival of platelets without and with platelet activation by collagen related peptide (CRP). METHODS: Platelets isolated from wild-type mice were exposed for 30 minutes to MDL-72527 (100 µM) with or without subsequent activation with CRP (2-5 µg/ml). Flow cytometry was employed to estimate cytosolic Ca2+-activity ([Ca2+]i) from Fluo-3 fluorescence, platelet degranulation from P-selectin abundance, integrin activation from αIIbß3 integrin abundance, generation of reactive oxygen species (ROS) from DCFDA fluorescence, phospholipid scrambling of the cell membrane from annexin-V-binding, platelet volume from forward scatter and aggregation utilizing staining with CD9-APC and CD9-PE. RESULTS: In the absence of CRP, exposure of platelets to MDL-72527 did not significantly modify [Ca2+]i, P-selectin abundance, αIIbß3 integrin abundance, ROS, annexin-V-binding, and forward scatter. The addition of 2-5 µg/ml CRP was followed by significant increase of [Ca2+]i, P-selectin abundance, αIIbß3 integrin activation, ROS abundance, annexin-V-binding, and aggregation as well as a significant decrease of forward scatter, all effects significantly blunted or virtually abolished in the presence of MDL-72527. CONCLUSIONS: MDL-72527 is a powerful inhibitor of platelet activation, apoptosis and aggregation.
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Ativação Plaquetária/efeitos dos fármacos , Putrescina/análogos & derivados , Compostos de Anilina/química , Animais , Apoptose/efeitos dos fármacos , Plaquetas/citologia , Plaquetas/metabolismo , Cálcio/química , Cálcio/metabolismo , Proteínas de Transporte/farmacologia , Membrana Celular/metabolismo , Feminino , Citometria de Fluxo , Masculino , Camundongos , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/antagonistas & inibidores , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Selectina-P/metabolismo , Peptídeos/farmacologia , Fosfatidilserinas , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Putrescina/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Xantenos/química , Poliamina OxidaseRESUMO
OBJECTIVE: Cyclophilin A (CyPA) is secreted under inflammatory conditions by various cell types. Whereas the important role of intracellular CyPA for platelet function has been reported, the effect of extracellular CyPA on platelet function has not been investigated yet. APPROACH AND RESULTS: Inhibition of extracellular CyPA through a novel specific inhibitor MM284 reduced thrombus after ferric chloride-induced injury in vivo. In vitro extracellular CyPA enhanced thrombus formation even in CyPA(-/-) platelets. Treatment of isolated platelets with recombinant CyPA resulted in platelet degranulation in a time- and dose-dependent manner. Inhibition of the platelet surface receptor extracellular matrix metalloproteinase inducer (cluster of differentiation 147) by an anticluster of differentiation 147 monoclonal antibody significantly reduced CyPA-dependent platelet degranulation. Pretreatment of platelets with CyPA enhanced their recruitment to mouse carotid arteries after arterial injury, which could be inhibited by an anticluster of differentiation 147 monoclonal antibody (intravital microscopy). The role of extracellular CyPA in adhesion could be confirmed by infusing CyPA(-/-) platelets in CyPA(+/+) mice and by infusing CyPA(+/+) platelets in CyPA(-/-) mice. Stimulation of platelets with CyPA induced phosphorylation of Akt, which could in turn be inhibited in the presence of phosphoinositid-3-kinase inhibitors. Akt-1(-/-) platelets revealed a markedly decreased degranulation on CyPA stimulation. Finally, ADP-induced platelet aggregation was attenuated by MM284, as well as by inhibiting paracrine-secreted CyPA without directly affecting Ca(2+)-signaling. CONCLUSIONS: Extracellular CyPA activates platelets via cluster of differentiation 147-mediated phosphoinositid-3-kinase/Akt-signaling, leading to enhanced adhesion and thrombus formation independently of intracellular CyPA. Targeting extracellular CyPA via a specific inhibitor may be a promising strategy for platelet inhibition without affecting critical functions of intracellular CyPA.
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Basigina/sangue , Plaquetas/enzimologia , Ciclofilina A/sangue , Fosfatidilinositol 3-Quinases/sangue , Adesividade Plaquetária , Proteínas Proto-Oncogênicas c-akt/sangue , Transdução de Sinais , Trombose/enzimologia , Animais , Plaquetas/efeitos dos fármacos , Lesões das Artérias Carótidas/sangue , Lesões das Artérias Carótidas/enzimologia , Lesões das Artérias Carótidas/genética , Degranulação Celular/efeitos dos fármacos , Cloretos , Ciclofilina A/antagonistas & inibidores , Ciclofilina A/genética , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Compostos Férricos , Fibrinolíticos/farmacologia , Humanos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Adesividade Plaquetária/efeitos dos fármacos , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , Proteínas Proto-Oncogênicas c-akt/deficiência , Proteínas Proto-Oncogênicas c-akt/genética , Transdução de Sinais/efeitos dos fármacos , Trombose/sangue , Trombose/induzido quimicamente , Trombose/genética , Trombose/prevenção & controle , Fatores de TempoRESUMO
OBJECTIVE: Recently, we reported that extracellular cyclophilin A (CyPA) is an important agonist for platelets. Whereas soluble CyPA-levels have been associated with cardiovascular risk factors, cell-bound CyPA has not been investigated yet. In this study, we analyzed for the first time platelet-bound CyPA in patients with symptomatic coronary artery disease (CAD). METHODS AND RESULTS: blood was obtained from 388 consecutive patients: 204 with stable CAD and 184 with acute coronary syndrome (76 with unstable angina, 78 with non ST-elevation myocardial infarction (NSTEMI), and 30 with STEMI). In vitro stimulation of platelets with classical agonists revealed an enhanced expression of CyPA on the platelet surface. In patients with stable CAD, platelet-bound CyPA correlated excellently with platelet activity measured by P-selectin exposure in flow cytometry. The analysis of classical risk factors for atherosclerosis revealed that patients with hypertension and hypercholesterolemia had significantly enhanced platelet-bound CyPA, whereas diabetes and smoking were not associated with enhanced CyPA-binding to the platelet surface. In multivariate analysis, hypercholesterolemia was the only significant predictor of enhanced platelet-bound CyPA. Interestingly, in patients with acute myocardial infarction (AMI) platelet-bound CyPA was significantly decreased compared with patients with stable CAD. CONCLUSIONS: Enhanced platelet-bound CyPA is associated with hypertension and hypercholesterolemia in stable CAD patients. In patients with AMI platelet-bound CyPA is significantly decreased.
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Angina Instável/sangue , Plaquetas/metabolismo , Doença da Artéria Coronariana/sangue , Ciclofilina A/sangue , Hipercolesterolemia/sangue , Hipertensão/sangue , Idoso , Idoso de 80 Anos ou mais , Angina Instável/complicações , Angina Instável/patologia , Plaquetas/patologia , Doença da Artéria Coronariana/complicações , Doença da Artéria Coronariana/patologia , Ciclofilina A/genética , Diabetes Mellitus/fisiopatologia , Feminino , Expressão Gênica , Humanos , Hipercolesterolemia/complicações , Hipercolesterolemia/patologia , Hipertensão/complicações , Hipertensão/patologia , Masculino , Pessoa de Meia-Idade , Selectina-P/sangue , Selectina-P/genética , Ativação Plaquetária , Ligação Proteica , Fatores de Risco , Fumar/fisiopatologiaAssuntos
Insuficiência Cardíaca , Mitocôndrias Cardíacas/patologia , Miocárdio , Cardiomiopatias , Feminino , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/patologia , Insuficiência Cardíaca/fisiopatologia , Humanos , Pessoa de Meia-Idade , Miocárdio/citologia , Miocárdio/patologia , TaquicardiaRESUMO
Focal pulsed field ablation (PFA) is a novel technique for treating cardiac arrhythmias. It has demonstrated positive results in initial studies and has a good safety profile. In recent studies, PFA was often utilized for first-time pulmonary vein isolation (PVI) and was performed under general anesthesia. In our study, we assessed the feasibility, safety, acute procedural efficacy, and efficiency of focal PFA under deep sedation in patients, 80% of whom had undergone at least one left atrial ablation previously. We treated 30 patients (71 ± 7, 46% male) using the CENTAURI system for various atrial arrhythmias, including atrial fibrillation, typical and atypical atrial flutter, and focal atrial tachycardia. The average procedure and fluoroscopy times were 122 ± 43 min and 9 ± 7 min, respectively. A total of 83.33% of patients received additional line ablations beyond PVI, specifically targeting the posterior box and anterior mitral line. All ablations were successfully performed in deep sedation with only one major and one minor complication observed. The major complication was a vasospasm of the right coronary artery during ablation of the cavotricuspid isthmus, which was treated successfully with intracoronary nitroglycerin. All patients could be discharged in sinus rhythm. Moreover, adenosine appears effective in identifying dormant conduction in some patients after focal PFA. In conclusion, focal PFA is an effective approach for complex left atrial ablations under deep sedation, offering both high efficacy and efficiency with a reliable safety profile. Studies on long-term outcomes are needed.
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AIMS: Cyclophilin A (CyPA) induces leucocyte recruitment and platelet activation upon release into the extracellular space. Extracellular CyPA therefore plays a critical role in immuno-inflammatory responses in tissue injury and thrombosis upon platelet activation. To date, CD147 (EMMPRIN) has been described as the primary receptor mediating extracellular effects of CyPA in platelets and leucocytes. The receptor for advanced glycation end products (RAGE) shares inflammatory and prothrombotic properties and has also been found to have similar ligands as CD147. In this study, we investigated the role of RAGE as a previously unknown interaction partner for CyPA. METHODS AND RESULTS: Confocal imaging, proximity ligation, co-immunoprecipitation, and atomic force microscopy were performed and demonstrated an interaction of CyPA with RAGE on the cell surface. Static and dynamic cell adhesion and chemotaxis assays towards extracellular CyPA using human leucocytes and leucocytes from RAGE-deficient Ager-/- mice were conducted. Inhibition of RAGE abrogated CyPA-induced effects on leucocyte adhesion and chemotaxis in vitro. Accordingly, Ager-/- mice showed reduced leucocyte recruitment and endothelial adhesion towards CyPA in vivo. In wild-type mice, we observed a downregulation of RAGE on leucocytes when endogenous extracellular CyPA was reduced. We furthermore evaluated the role of RAGE for platelet activation and thrombus formation upon CyPA stimulation. CyPA-induced activation of platelets was found to be dependent on RAGE, as inhibition of RAGE, as well as platelets from Ager-/- mice showed a diminished activation and thrombus formation upon CyPA stimulation. CyPA-induced signalling through RAGE was found to involve central signalling pathways including the adaptor protein MyD88, intracellular Ca2+ signalling, and NF-κB activation. CONCLUSION: We propose RAGE as a hitherto unknown receptor for CyPA mediating leucocyte as well as platelet activation. The CyPA-RAGE interaction thus represents a novel mechanism in thrombo-inflammation.
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Ciclofilina A , Trombose , Camundongos , Humanos , Animais , Ciclofilina A/genética , Ciclofilina A/metabolismo , Produtos Finais de Glicação Avançada , Ligantes , Inflamação , Basigina/metabolismo , Trombose/genéticaRESUMO
Imaging of pulmonary vein (PV) anatomy by angiography before pulmonary vein isolation (PVI) for atrial fibrillation (AF) has long been standard practice in many centers. Nowadays, very accurate anatomical maps can be generated by the use of high-resolution mapping catheters, and very effective ablation lesions can be generated by the use of the high-power, short-duration (HPSD) technique. In our center, PV angiography was routinely performed before PVI. However, since there is no clear evidence for this, we refrained from performing PV angiography. This study aimed to investigate whether PV angiography is still necessary when using high-resolution mapping catheters after ablation in the high-power, short-duration (HPSD) technique. A total of 139 consecutive patients with atrial fibrillation (66.25 ± 11.68 years old, 62.39% male) undergoing radiofrequency PVI were included in the study. Ablation was performed with the HPSD technique using a fixed protocol for energy delivery of 50 watts (contact force 3-20 g). We observed no significant effect on the efficacy, efficiency and complications of the ablation procedure if pulmonary vein angiography was omitted before HPSD PVI. Thus, using our protocol, it may be useful that PV angiography is avoided, especially in young patients and those with chronic renal disease.
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Spatial transcriptomics of histological sections have revolutionized research in life sciences and enabled unprecedented insights into genetic processes involved in tissue reorganization. However, in contrast to genomic analysis, the actual biomolecular composition of the sample has fallen behind, leaving a gap of potentially highly valuable information. Raman microspectroscopy provides untargeted spatiomolecular information at high resolution, capable of filling this gap. In this study we demonstrate spatially resolved Raman "spectromics" to reveal homogeneity, heterogeneity and dynamics of cell matrix on molecular levels by repurposing state-of-the-art bioinformatic analysis tools commonly used for transcriptomic analyses. By exploring sections of murine myocardial infarction and cardiac hypertrophy, we identify myocardial subclusters when spatially approaching the pathology, and define the surrounding metabolic and cellular (immune-) landscape. Our innovative, label-free, non-invasive "spectromics" approach could therefore open perspectives for a profound characterization of histological samples, while additionally allowing the combination with consecutive downstream analyses of the very same specimen.
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Disciplinas das Ciências Biológicas , Análise Espectral Raman , Animais , Camundongos , Genômica , Biologia Computacional , CitosolRESUMO
During megakaryopoiesis, megakaryocytes (MK) undergo cellular morphological changes with strong modification of membrane composition and lipid signaling. Here we adopt a lipid-centric multiomics approach to create a quantitative map of the MK lipidome during maturation and proplatelet formation. Data reveal that MK differentiation is driven by an increased fatty acyl import and de novo lipid synthesis, resulting in an anionic membrane phenotype. Pharmacological perturbation of fatty acid import and phospholipid synthesis blocked membrane remodeling and directly reduced MK polyploidization and proplatelet formation resulting in thrombocytopenia. The anionic lipid shift during megakaryopoiesis was paralleled by lipid-dependent relocalization of the scaffold protein CKIP-1 and recruitment of the kinase CK2α to the plasma membrane, which seems to be essential for sufficient platelet biogenesis. Overall, this study provides a framework to understand how the MK lipidome is altered during maturation and the impact of MK membrane lipid remodeling on MK kinase signaling involved in thrombopoiesis.
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BACKGROUND: After pulmonary vein isolation (PVI) for atrial fibrillation (AF), it is common as an endpoint to demonstrate an exit block from the pulmonary veins (PVs) in addition to an entrance block into them. By using high-resolution mapping catheters, even very small signals can be detected. OBJECTIVES: We investigated whether additional exit block testing is still necessary when using high-resolution mapping catheters after ablation in high-power short-duration (HPSD) techniques. MATERIALS AND METHODS: Overall, 114 patients with AF (average age, 65.14⯱ 11.3 years; 65.8% male) undergoing radiofrequency PVI were included in the study. Ablation was performed with the HPSD technique using a fixed protocol for energy delivery of 50 W (contact force 3-20â¯g). Entrance and exit block were tested with a high-resolution mapping catheter. Isolation of the PVs was achieved in all patients. RESULTS: Capture of local PV tissue was demonstrated in all patients after PVI and exit block was present in all patients after entrance block was detected using a high-resolution mapping catheter. CONCLUSION: Exit block testing in addition to the demonstration of an entrance block as an endpoint of PVI seems to have no additional benefit and might no longer be necessary when a high-resolution mapping catheter is used in HPSD ablation for PVI of AF.
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Fibrilação Atrial , Ablação por Cateter , Veias Pulmonares , Humanos , Masculino , Pessoa de Meia-Idade , Idoso , Feminino , Veias Pulmonares/cirurgia , Ablação por Cateter/métodos , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/cirurgia , Resultado do Tratamento , RecidivaRESUMO
Platelet activation plays a critical role in thrombosis. Inhibition of platelet activation is a cornerstone in treatment of acute organ ischemia. Platelet ACKR3 surface expression is independently associated with all-cause mortality in CAD patients. In a novel genetic mouse strain, we show that megakaryocyte/platelet-specific deletion of ACKR3 results in enhanced platelet activation and thrombosis in vitro and in vivo. Further, we performed ischemia/reperfusion experiments (transient LAD-ligation and tMCAO) in mice to assess the impact of genetic ACKR3 deficiency in platelets on tissue injury in ischemic myocardium and brain. Loss of platelet ACKR3 enhances tissue injury in ischemic myocardium and brain and aggravates tissue inflammation. Activation of platelet-ACKR3 via specific ACKR3 agonists inhibits platelet activation and thrombus formation and attenuates tissue injury in ischemic myocardium and brain. Here we demonstrate that ACKR3 is a critical regulator of platelet activation, thrombus formation and organ injury following ischemia/reperfusion.
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Traumatismo por Reperfusão , Trombose , Animais , Plaquetas/metabolismo , Humanos , Camundongos , Ativação Plaquetária , Reperfusão , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/metabolismo , Trombose/metabolismoRESUMO
COVID-19 may lead to severe acute respiratory distress syndrome (ARDS) resulting in increased morbidity and mortality. Heart failure and/or pre-existing cardiovascular disease may correlate with poor outcomes and thus require special attention from treating physicians. The present study sought to investigate a possible impact of impaired myocardial function as well as myocardial distress markers on mortality or ARDS with need for mechanical ventilation in 157 consecutive patients with confirmed SARS-CoV-2 infection. All patients were admitted and treated at the University Hospital of Tübingen, Germany, during the first wave of the pandemic. Electrocardiography, echocardiography, and routine blood sampling were performed at hospital admission. Impaired left-ventricular and right-ventricular function, tricuspid regurgitation > grade 1, and elevated RV-pressure as well as thrombotic and myocardial distress markers (D-dimers, NT-pro-BNP, and troponin-I) were associated with mechanical ventilation and/or all-cause mortality. Impaired cardiac function is more frequent amidst ARDS, leading to subsequent need for mechanical ventilation, and thus denotes a poor outcome in COVID-19. Since a causal treatment for SARS-CoV-2 infection is still lacking, guideline-compliant cardiovascular evaluation and treatment remains the best approach to improve outcomes in COVID-19 patients with cardiovascular comorbidities.
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BACKGROUND: Acute respiratory distress syndrome (ARDS) is considered the main cause of COVID-19 associated morbidity and mortality. Early and reliable risk stratification is of crucial clinical importance in order to identify persons at risk for developing a severe course of disease. Deceleration capacity (DC) of heart rate as a marker of cardiac autonomic function predicts outcome in persons with myocardial infarction and heart failure. We hypothesized that reduced modulation of heart rate may be helpful in identifying persons with COVID-19 at risk for developing ARDS. METHODS: We prospectively enrolled 60 consecutive COVID-19 positive persons presenting at the University Hospital of Tuebingen. Arterial blood gas analysis and 24 h-Holter ECG recordings were performed and analyzed at admission. The primary end point was defined as development of ARDS with regards to the Berlin classification. RESULTS: 61.7% (37 of 60 persons) developed an ARDS. In persons with ARDS DC was significantly reduced when compared to persons with milder course of infection (3.2 ms vs. 6.6 ms, p < 0.001). DC achieved a good discrimination performance (AUC = 0.76) for ARDS in COVID-19 persons. In a multivariate analysis, decreased DC was associated with the development of ARDS. CONCLUSION: Our data suggest a promising role of DC to risk stratification in COVID-19.
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COVID-19 , Síndrome do Desconforto Respiratório , Desaceleração , Eletrocardiografia Ambulatorial , Humanos , Síndrome do Desconforto Respiratório/diagnóstico , Síndrome do Desconforto Respiratório/epidemiologia , Síndrome do Desconforto Respiratório/etiologia , SARS-CoV-2RESUMO
Surface receptor-mediated adhesion is a fundamental step in the recruitment of leukocytes and platelets, as well as platelet-leukocyte interactions. The surface receptor CD147 is crucially involved in host defense against self-derived and invading targets, as well as in thrombosis. In the current study, we describe the previously unknown interaction of CD147 with integrin αMß2 (Mac-1) in this context. Using binding assays, we were able to show a stable interaction of CD147 with Mac-1 in vitro. Leukocytes from Mac-1-/- and CD147+/- mice showed a markedly reduced static adhesion to CD147- and Mac-1-coated surfaces, respectively, compared to wild-type mice. Similarly, we observed reduced rolling and adhesion of monocytes under flow conditions when cells were pre-treated with antibodies against Mac-1 or CD147. Additionally, as assessed by antibody inhibition experiments, CD147 mediated the dynamic adhesion of platelets to Mac-1-coated surfaces. The interaction of CD147 with Mac-1 is a previously undescribed mechanism facilitating the adhesion of leukocytes and platelets.
Assuntos
Basigina/metabolismo , Plaquetas/citologia , Adesão Celular , Leucócitos/citologia , Antígeno de Macrófago 1/metabolismo , Animais , Camundongos , Ligação ProteicaRESUMO
BACKGROUND: COVID-19 infection may cause severe respiratory distress and is associated with increased morbidity and mortality. Impaired cardiac function and/or pre-existing cardiovascular disease may be associated with poor prognosis. In the present study, we report a comprehensive cardiovascular characterization in the first consecutive collective of patients that was admitted and treated at the University Hospital of Tübingen, Germany. METHODS: 123 consecutive patients with COVID-19 were included. Routine blood sampling, transthoracic echocardiography and electrocardiography were performed at hospital admission. RESULTS: We found that impaired left-ventricular and right-ventricular function as well as tricuspid regurgitation > grade 1 were significantly associated with higher mortality. Furthermore, elevated levels of myocardial distress markers (troponin-I and NT pro-BNP) were associated with poor prognosis in this patient collective. CONCLUSION: Impaired cardiac function is associated with poor prognosis in COVID-19 positive patients. Consequently, treatment of these patients should include careful guideline-conform cardiovascular evaluation and treatment. Thus, formation of a competent Cardio-COVID-19 team may represent a major clinical measure to optimize therapy of cardiovascular patients during this pandemic.