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Endothelial progenitor cells (EPCs) are involved in vascular repair and modulate properties of smooth muscle cells (SMCs) relevant for their contribution to neointima formation following injury. Considering the relevant role of the CXCL12-CXCR4 axis in vascular homeostasis and the potential of EPCs and SMCs to release CXCL12 and express CXCR4, we analyzed the engagement of the CXCL12-CXCR4 axis in various modes of EPC-SMC interaction relevant for injury- and lipid-induced atherosclerosis. We now demonstrate that the expression and release of CXCL12 is synergistically increased in a CXCR4-dependent mechanism following EPC-SMC interaction during co-cultivation or in response to recombinant CXCL12, thus establishing an amplifying feedback loop Additionally, mechanical injury of SMCs induces increased release of CXCL12, resulting in enhanced CXCR4-dependent recruitment of EPCs to SMCs. The CXCL12-CXCR4 axis is crucially engaged in the EPC-triggered augmentation of SMC migration and the attenuation of SMC apoptosis but not in the EPC-mediated increase in SMC proliferation. Compared to EPCs alone, the alliance of EPC-SMC is superior in promoting the CXCR4-dependent proliferation and migration of endothelial cells. When direct cell-cell contact is established, EPCs protect the contractile phenotype of SMCs via CXCL12-CXCR4 and reverse cholesterol-induced transdifferentiation toward a synthetic, macrophage-like phenotype. In conclusion we show that the interaction of EPCs and SMCs unleashes a CXCL12-CXCR4-based autoregulatory feedback loop promoting regenerative processes and mediating SMC phenotype control to potentially guard vascular homeostasis.
Assuntos
Vasos Sanguíneos/metabolismo , Quimiocina CXCL12/metabolismo , Células Progenitoras Endoteliais/metabolismo , Homeostase , Miócitos de Músculo Liso/metabolismo , Receptores CXCR4/metabolismo , Aterosclerose/etiologia , Aterosclerose/metabolismo , Aterosclerose/patologia , Biomarcadores , Movimento Celular , Células Cultivadas , Quimiocina CXCL12/genética , Expressão Gênica , Humanos , Neointima/genética , Neointima/metabolismo , Fenótipo , Ligação Proteica , Receptores CXCR4/genética , Transdução de SinaisRESUMO
Myocardial infarction remains the most common cause of heart failure with adverse remodeling. MicroRNA (miR)155 is upregulated following myocardial infarction and represents a relevant regulatory factor for cardiac remodeling by engagement in cardiac inflammation, fibrosis and cardiomyocyte hypertrophy. Here, we investigated the role of miR155 in cardiac remodeling and dysfunction following myocardial infarction in a dyslipidemic mouse model. Myocardial infarction was induced in dyslipidemic apolipoprotein E-deficient (ApoE-/-) mice with and without additional miR155 knockout by ligation of the LAD. Four weeks later, echocardiography was performed to assess left ventricular (LV) dimensions and function, and mice were subsequently sacrificed for histological analysis. Echocardiography revealed no difference in LV ejection fractions, LV mass and LV volumes between ApoE-/- and ApoE-/-/miR155-/- mice. Histology confirmed comparable infarction size and unaltered neoangiogenesis in the myocardial scar. Notably, myofibroblast density was significantly decreased in ApoE-/-/miR155-/- mice compared to the control, but no difference was observed for total collagen deposition. Our findings reveal that genetic depletion of miR155 in a dyslipidemic mouse model of myocardial infarction does not reduce infarction size and consecutive heart failure but does decrease myofibroblast density in the post-ischemic scar.
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MicroRNAs/genética , Infarto do Miocárdio/genética , Miofibroblastos/metabolismo , Função Ventricular Esquerda/genética , Animais , Modelos Animais de Doenças , Ecocardiografia/métodos , Fibrose/genética , Fibrose/metabolismo , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/metabolismo , Ventrículos do Coração/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infarto do Miocárdio/metabolismo , Miocárdio/metabolismo , Volume Sistólico/genética , Remodelação Ventricular/genéticaRESUMO
Background: Chronic inflammation is a cardiovascular risk factor, and interleukin-1ß (IL-1ß) is central to the inflammatory host response. Platelets contain the NLRP3 inflammasome and are able to translate IL-1ß messenger RNA (mRNA) and secrete mature IL-1ß upon activation. However, the role of a chronic inflammatory environment in platelet IL-1ß mRNA and protein content remains unclear. Objectives: The aim of the current study was to investigate intracellular platelet IL-1ß and IL-1ß mRNA in a chronic inflammatory state. Methods: Sixty-five patients with stable inflammation (ie, high-sensitivity C-reactive protein within predefined margins in 2 separate measurements) were stratified according to high-sensitivity C-reactive protein levels in low (0.0-0.9 mg/L), medium (1.0-2.9 mg/L), and high (3.0-9.9 mg/L) risk groups. Platelet reactivity as well as platelet IL-1ß protein synthesis were studied. Results: The highest risk group was characterized by a distinct cardiovascular risk profile and approximately 20% higher platelet counts. While platelet reactivity was not different, a reduction in intracellular platelet IL-1ß mRNA and IL-1ß protein levels was observed in the highest risk group and was linked to decreased platelet size and granularity. This signature suggests a phenotype of chronic IL-1ß secretion and could be experimentally phenocopied by stimulation of platelets from healthy volunteers with either TRAP-6 or collagen related peptide (CRP-XL). Conclusion: Our data suggest a phenotype of chronic IL-1ß secretion by platelets in patients with chronic sterile inflammation.
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Microparticles represent a heterogeneous population of vesicles with a diameter of 100 to 1000 nm that are released by budding of the plasma membrane and express antigens specific of their parental cells. Although microparticle formation represents a physiological phenomenon, a multitude of pathologies are associated with a considerable increase in circulating microparticles, including inflammatory and autoimmune diseases, atherosclerosis, and malignancies. Microparticles display an broad spectrum of bioactive substances and receptors on their surface and harbor a concentrated set of cytokines, signaling proteins, mRNA, and microRNA. Recent studies provided evidence for the concept of microparticles as veritable vectors for the intercellular exchange of biological signals and information. Indeed, microparticles may transfer part of their components and content to selected target cells, thus mediating cell activation, phenotypic modification, and reprogramming of cell function. Because microparticles readily circulate in the vasculature, they may serve as shuttle modules and signaling transducers not only in their local environment but also at remarkable distance from their site of origin. Altogether, this transcellular delivery system may extend the confines of the limited transcriptome and proteome of recipient cells and establishes a communication network in which specific properties and information among cells can be efficiently shared. At least in same cases, the sequential steps of the transfer process underlie complex regulatory mechanisms, including selective sorting ("packaging") of microparticle components and content, specificity of interactions with target cells determined by surface receptors, and ultimately finely tuned and signal-dependent release and delivery of microparticle content.
Assuntos
Doenças Cardiovasculares/metabolismo , Comunicação Celular/fisiologia , Micropartículas Derivadas de Células/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Transdução de Sinais/fisiologia , Animais , HumanosRESUMO
Background: Intravenous iron supplementation is an established therapy for patients with heart failure (HF) and concomitant iron deficiency reducing the risk of HF hospitalization. However, concerns persist regarding potential adverse vascular effects, since iron may induce oxidative stress, inflammation, and apoptosis of endothelial cells. To assess endothelial health following ferric carboxymaltose (FCM) administration, we analyzed the profile of circulating endothelial microvesicles (EMVs) and endothelial progenitor cells (EPCs) in a cohort of 23 HF patients using flow cytometry. Results: Compared to healthy subjects, baseline levels of CD31+/CD41- EMVs were higher and EMVs featured a more apoptotic phenotype in HF patients. Following FCM administration, EMV levels showed a rapid but transient increase and displayed an altered phenotype profile with dominant augmentation of EMVs expressing inducible markers CD62E and CD54, indicating endothelial inflammatory activation and injury. Levels of circulating vasoregenerative CD45lowCD34+KDR+ EPCs were lower in HF patients and FCM application resulted in an early decrease of EPCs followed by substantial mobilization into the circulation after one week. Levels of EMVs and EPCs returned to baseline values within two and four weeks, respectively. HF patients with additional chronic kidney disease showed an elevated EMV/EPC ratio and diminished EPC mobilization, suggesting impaired vascular repair capacity. Providing a mechanistic link, in vitro experiments with cultured endothelial cells revealed that FCM dose-dependently promotes endothelial apoptosis, increases expression of adhesion molecules and CXCL12, and triggers generation of EMVs. Conclusion: Intravenous iron supplementation with FCM in HF patients induces a biphasic response with initial increased release of CD62E+ and CD54+ enriched EMVs and subsequent mobilization of EPCs, indicating endothelial dysfunction upon FCM and suggesting consecutive engagement of a defense program aimed to reconstitute vascular health.
Assuntos
Células Progenitoras Endoteliais , Insuficiência Cardíaca , Deficiências de Ferro , Humanos , Ferro , Insuficiência Cardíaca/tratamento farmacológico , Suplementos NutricionaisRESUMO
BACKGROUND: By low-density lipoprotein (LDL) reduction, statins play an important role in cardiovascular risk modification. Incompletely understood pleiotropic statin effects include vasoprotection that might originate from mobilisation and differentiation of vascular progenitor cells. Data on the potentially differential impact of statin treatment intensity on circulating progenitor cells in patients undergoing percutaneous coronary intervention (PCI) are scarce. This study examines the potential association of different permanent statin treatment regimens on circulating progenitor cells in patients with coronary syndrome. METHODS AND RESULTS: In a monocentric prospective all-comers study, 105 consecutive cases scheduled for coronary angiography due to either (A) non-invasive proof of ischemia and chronic coronary syndrome (CCS) or (B) troponin-positive acute coronary syndrome (ACS) were included. According to the 2018 American College of Cardiology Guidelines on Blood Cholesterol, patients were clustered depending on their respective permanent statin treatment regimen in either a high- to moderate-intensity statin treatment (HIST) or a low-intensity statin treatment (LIST) group. Baseline characteristics including LDL levels were comparable. From blood drawn at the time of PCI, peripheral blood mononuclear cells were isolated, cultivated and counted and, by density gradient centrifugation, levels of circulating progenitor cells were determined using fluorescence-activated cell sorting (FACS) analysis. In ACS patients both absolute and relative numbers of circulating early-outgrowth endothelial progenitor cells (EPCs) concurrently were significantly lower in the HIST group as compared to the LIST group. This effect was more pronounced in ACS patients than in CCS patients. Both in ACS and CCS patients, HIST caused a significant reduction of the number of circulating SMPCs. CONCLUSIONS: In patients undergoing PCI, a dose intensity-dependent and LDL level-independent pro-differentiating vasoprotective pleiotropic capacity of statins for EPC and SMPC is demonstrated.
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Síndrome Coronariana Aguda , Inibidores de Hidroximetilglutaril-CoA Redutases , Intervenção Coronária Percutânea , Síndrome Coronariana Aguda/tratamento farmacológico , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Leucócitos Mononucleares , Intervenção Coronária Percutânea/efeitos adversos , Estudos Prospectivos , Células-TroncoRESUMO
BACKGROUND: Smooth muscle cells (SMCs) are the main driver of neointima formation and restenosis following vascular injury. In animal models, endothelial progenitor cells (EPCs) accelerate endothelial regeneration and reduce neointima formation after arterial injury; however, EPC-capture stents do not reduce target vessel failure compared with conventional stents. Here we examined the influence of EPCs on features of SMCs pivotal for their impact on injury-induced neointima formation including proliferation, migration, and phenotype switch. METHODS AND RESULTS: EPCs, their conditioned medium, and EPC-derived microparticles induced proliferation of SMCs while limiting their apoptosis. In transwell membrane experiments and scratch assays, EPCs stimulated migration of SMCs and accelerated their recovery from scratch-induced injury. Treatment of SMCs with an EPC-derived conditioned medium or microparticles triggered transformation of SMCs toward a synthetic phenotype. However, co-cultivation of EPCs and SMCs enabling direct cell-cell contacts preserved their original phenotype and protected from the transformative effect of SMC cholesterol loading. Adhesion of EPCs to SMCs was stimulated by SMC injury and reduced by blocking CXCR2 and CCR5. Interaction of EPCs with SMCs modulated their secretory products and synergistically increased the release of selected chemokines. Following carotid wire injury in athymic mice, injection of EPCs resulted not only in reduced neointima formation but also in altered cellular composition of the neointima with augmented accumulation of SMCs. CONCLUSION: EPCs stimulate proliferation and migration of SMCs and increase their neointimal accumulation following vascular injury. Furthermore, EPCs context-dependently modify the SMC phenotype with protection from the transformative effect of cholesterol when a direct cell-cell contact is established.
Assuntos
Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Células Progenitoras Endoteliais , Neointima , Receptores de Interleucina-8B/metabolismo , Regeneração/fisiologia , Lesões do Sistema Vascular , Adaptação Fisiológica/fisiologia , Animais , Apoptose , Artérias/lesões , Artérias/metabolismo , Células Cultivadas , Modelos Animais de Doenças , Células Progenitoras Endoteliais/patologia , Células Progenitoras Endoteliais/fisiologia , Camundongos , Miócitos de Músculo Liso , Neointima/etiologia , Neointima/metabolismo , Neointima/patologia , Neointima/prevenção & controle , Receptores CCR5/metabolismo , Transdução de Sinais/fisiologia , Lesões do Sistema Vascular/metabolismo , Lesões do Sistema Vascular/patologiaRESUMO
BACKGROUND: Angiogenic early outgrowth cells (EOCs) have been reported to contribute to endothelial regeneration and to limit neointima formation after vascular injury. Vascular pathologies comprise platelet activation and concomitant generation of platelet microparticles (PMPs). We hypothesized that PMPs may interact with EOCs in the context of vascular injury and modulate their regenerative potential. METHODS AND RESULTS: Using flow cytometry, confocal microscopy, and scanning electron microscopy, we demonstrated the binding of thrombin/collagen-induced PMPs to EOCs with subsequent membrane assimilation and incorporation. This interaction promoted phenotypic alterations of EOCs with increased expression of endothelial cell markers and transfer of the chemokine receptor CXCR4 to EOCs with enhanced responsiveness to its ligand CXCL12/SDF-1alpha. In addition, PMPs augmented the adhesion of EOCs to extracellular matrix components and to the injured vessel wall and accelerated cytoskeletal reorganization and migration of EOCs. PMPs induced changes in the EOC secretome toward a more proangiogenic profile and amplified the EOC-mediated induction of proliferation, migration, and capillary tube formation by mature endothelial cells. Compared with untreated EOCs, the injection of PMP-treated EOCs resulted in accelerated reendothelialization after arterial denudation injury in athymic nude mice, whereas the EOC-mediated reduction of neointima formation remained unchanged. CONCLUSIONS: Our data provide evidence that PMPs can boost the potential of EOCs to restore endothelial integrity after vascular injury. Major mechanisms involve the enhancement of EOC recruitment, migration, differentiation, and release of proangiogenic factors.
Assuntos
Plaquetas/fisiologia , Lesões das Artérias Carótidas/fisiopatologia , Micropartículas Derivadas de Células/fisiologia , Células Endoteliais/fisiologia , Neovascularização Fisiológica/fisiologia , Animais , Biomarcadores/metabolismo , Plaquetas/citologia , Artérias Carótidas/patologia , Artérias Carótidas/fisiologia , Lesões das Artérias Carótidas/patologia , Comunicação Celular/fisiologia , Diferenciação Celular/fisiologia , Divisão Celular/fisiologia , Movimento Celular/fisiologia , Células Cultivadas , Quimiocina CXCL12/metabolismo , Citoesqueleto/fisiologia , Modelos Animais de Doenças , Células Endoteliais/citologia , Citometria de Fluxo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Receptores CXCR4/metabolismo , Regeneração/fisiologia , Veias Umbilicais/citologiaRESUMO
BACKGROUND: Receptor binding of complement C5a leads to proinflammatory activation of many cell types, but the role of receptor-mediated action during arterial remodeling after injury has not been studied. In the present study, we examined the contribution of the C5a receptor (C5aR) to neointima formation in apolipoprotein E-deficient mice employing a C5aR antagonist (C5aRA) and a C5aR-blocking monoclonal antibody. METHODS AND RESULTS: Mice fed an atherogenic diet were subjected to wire-induced endothelial denudation of the carotid artery and treated with C5aRA and anti-C5aR-blocking monoclonal antibody or vehicle control. Compared with controls, neointima formation was significantly reduced in mice receiving C5aRA or anti-C5aR-blocking monoclonal antibody for 1 week but not for 3 weeks, attributable to an increased content of vascular smooth muscle cells, whereas a marked decrease in monocyte and neutrophil content was associated with reduced vascular cell adhesion molecule-1. As assessed by immunohistochemistry, reverse transcription polymerase chain reaction, and flow cytometry, C5aR was expressed in lesional and cultured vascular smooth muscle cells, upregulated by injury or tumor necrosis factor-alpha, and reduced by C5aRA. Plasma levels and neointimal plasminogen activator inhibitor-1 peaked 1 week after injury and were downregulated in C5aRA-treated mice. In vitro, C5a induced plasminogen activator inhibitor-1 expression in endothelial cells and vascular smooth muscle cells in a C5aRA-dependent manner, possibly accounting for higher vascular smooth muscle cell immigration. CONCLUSIONS: One-week treatment with C5aRA or anti-C5aR-blocking monoclonal antibody limited neointimal hyperplasia and inflammatory cell content and was associated with reduced vascular cell adhesion molecule-1 expression. However, treatment for 3 weeks failed to reduce but rather stabilized plaques, likely by reducing vascular plasminogen activator inhibitor-1 and increasing vascular smooth muscle cell migration.
Assuntos
Anticorpos Monoclonais/farmacologia , Aterosclerose/tratamento farmacológico , Aterosclerose/metabolismo , Músculo Liso Vascular/efeitos dos fármacos , Oligopeptídeos/farmacologia , Receptor da Anafilatoxina C5a/antagonistas & inibidores , Animais , Apolipoproteínas E/genética , Aterosclerose/patologia , Lesões das Artérias Carótidas/tratamento farmacológico , Lesões das Artérias Carótidas/metabolismo , Lesões das Artérias Carótidas/patologia , Movimento Celular/efeitos dos fármacos , Movimento Celular/imunologia , Complemento C5a/metabolismo , Modelos Animais de Doenças , Citometria de Fluxo , Leucócitos/citologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Receptor da Anafilatoxina C5a/genética , Receptor da Anafilatoxina C5a/imunologia , Serpina E2 , Serpinas/metabolismo , Túnica Íntima/efeitos dos fármacos , Túnica Íntima/imunologia , Túnica Íntima/patologia , Molécula 1 de Adesão de Célula Vascular/metabolismoRESUMO
OBJECTIVE: Platelet activation mediates multiple cellular responses, including secretion of chemokines such as RANTES (CCL5), and formation of platelet microparticles (PMPs). We studied the role of PMPs in delivering RANTES and promoting monocyte recruitment. METHODS AND RESULTS: Here we show that PMPs contain substantial amounts of RANTES and deposit RANTES on activated endothelium or murine atherosclerotic carotid arteries. RANTES deposition is facilitated by flow conditions and more efficient than that conferred by PMP supernatants. Interactions of PMPs with activated endothelium in flow were mostly characterized by rolling. RANTES deposition showed a diffuse distribution pattern and was rarely colocalized with firmly adherent PMPs, substantiating that RANTES deposition occurs during transient interactions. Importantly, preperfusion with PMPs enhanced monocyte arrest on activated endothelium or atherosclerotic carotid arteries, which could be inhibited by a blocking antibody or a RANTES receptor antagonist. Blockade or deficiency of PMP-expressed adhesion receptors demonstrated differential requirement of P-selectin, glycoprotein Ib (GPIb), GPIIb/IIIa, and junctional adhesion molecule-A for PMP interactions with endothelium, PMP-dependent RANTES deposition, and subsequent monocyte arrest. CONCLUSION: Circulating PMPs may serve as a finely tuned transcellular delivery system for RANTES, triggering monocyte arrest to inflamed and atherosclerotic endothelium, introducing a novel mechanism for platelet-dependent monocyte recruitment in inflammation and atherosclerosis.
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Plaquetas/citologia , Plaquetas/imunologia , Quimiocina CCL5/metabolismo , Quimiocinas CC/metabolismo , Endotélio Vascular/imunologia , Monócitos/imunologia , Trombose/imunologia , Animais , Apolipoproteínas E/genética , Artérias Carótidas/imunologia , Artérias Carótidas/patologia , Linhagem Celular , Movimento Celular/imunologia , Endotélio Vascular/citologia , Humanos , Camundongos , Camundongos Mutantes , Monócitos/citologia , Tamanho da Partícula , Ativação Plaquetária/imunologiaRESUMO
Platelet-derived chemokines, such as regulated on activation, normal T expressed and secreted (RANTES; CC chemokine ligand 5), platelet factor 4 [PF4; CXC chemokine ligand 4 (CXCL4)], and epithelial neutrophil-activating protein 78 (ENA-78; CXCL5), or precursors, such as beta-thromboglobulin, which can be processed to neutrophil-activating protein-2 (NAP-2; CXCL7), may play an important role in monocyte recruitment during atherogenesis. Platelets can deposit chemokines on inflamed endothelium; however, little is known about differential or additive effects of platelet chemokines on monocyte arrest. Here, we demonstrate that preincubation of activated human microvascular endothelial cells (HMVECs) with RANTES, PF4, or NAP-2 but not ENA-78 dose-dependently increased surface immobilization and subsequent monocyte arrest in flow. RANTES was the most potent and efficient arrest chemokine. Pretreatment of HMVECs with beta-thromboglobulin enhanced monocyte arrest in the presence of cathepsin G generating NAP-2. Combined pretreatment of HMVECs with RANTES and PF4 at suboptimal concentrations synergistically increased arrest, and preincubation with chondroitinase ABC abrogated RANTES- and PF4-induced monocyte arrest. This was associated with reduced expression of chondroitin sulfate, RANTES, and PF4 on the HMVEC surface. Perfusion of HMVECs with platelets known to deposit RANTES and PF4 on the endothelial surface enhanced monocyte arrest, which was inhibited by Met-RANTES, chondroitinase, or a blocking antibody to PF4 but not to ENA-78. The relevance of platelet-derived chemokines was confirmed in adhesion assays with activated whole blood, where Met-RANTES and to a lesser extent, antibodies to PF4 and NAP-2 inhibited arrest of CD14-positive monocytes. Thus, multiple platelet-derived chemokines and processable precursors, which can be presented by specific endothelial proteoglycans, may contribute and cooperate differentially to induce monocyte recruitment.
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Plaquetas/fisiologia , Quimiocinas/metabolismo , Endotélio Vascular/metabolismo , Migração e Rolagem de Leucócitos/fisiologia , Monócitos/fisiologia , Anticorpos Monoclonais/farmacologia , Arteriosclerose/metabolismo , Arteriosclerose/patologia , Adesão Celular/efeitos dos fármacos , Adesão Celular/fisiologia , Linhagem Celular , Quimiocinas/farmacologia , Condroitina ABC Liase/farmacologia , Sinergismo Farmacológico , Endotélio Vascular/patologia , Humanos , Inflamação/metabolismo , Inflamação/patologia , Migração e Rolagem de Leucócitos/efeitos dos fármacos , Receptores de Lipopolissacarídeos/metabolismo , Ativação de Macrófagos/efeitos dos fármacos , Ativação de Macrófagos/fisiologiaRESUMO
BACKGROUND: Sclerostin is an endocrine regulator in chronic kidney disease - mineral and bone disorder (CKD-MBD). Validation of assay comparability and pre-analytical handling is mandatory for establishment of sclerostin as a biomarker. METHODS: Blood samples (serum, EDTA, heparin and citrate plasma) were obtained from 12 hemodialysis (HD) patients after the long dialysis interval. Passing-Bablok regression analysis and Bland-Altman difference plots were used to evaluate the agreement between sclerostin levels measured with two commercially available ELISAs from TECOmedical and Biomedica. RESULTS: Independent of the sample type, the agreement of the two assays was poor with a strong proportional but no systematic bias. Compared to the TECOmedical assay, the Biomedica test yielded almost 2-fold higher sclerostin values throughout all sample types. Spike recovery and linear dilution studies revealed a higher accuracy of the TECOmedical assay (97% and 96%) compared to the Biomedica assay (118% and 78%). Sclerostin levels were stable within 4 hours after sample collection, in particular when analyzed in plasma. In contrast to the Biomedica assay, the TECOmedical showed a systematic but no proportional bias between serum and plasma samples with higher values for plasma samples. Among the 3 different plasma samples no systematic error could be documented. CONCLUSION: Careful consideration of the pre-analytical handling and comparative assay validation are necessary to facilitate a more differentiated interpretation of studies reporting circulating sclerostin levels. The presence of a proportional bias demonstrates that in HD patients the two ELISAs for measuring sclerostin should not be used interchangeably. Furthermore, caution is necessary when comparing sclerostin results obtained from different blood sample types.
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Percutaneous transluminal angioplasty with stent implantation is used to dilate arteries narrowed by atherosclerotic plaques and to revascularize coronary arteries occluded by atherothrombosis in myocardial infarction. Commonly applied drug-eluting stents release antiproliferative or anti-inflammatory agents to reduce the incidence of in-stent stenosis. However, these stents may still lead to in-stent stenosis; they also show increased rates of late stent thrombosis, an obstacle to optimal revascularization possibly related to endothelial recovery. Here, we examined the contribution of neutrophils and neutrophilic granule proteins to arterial healing after injury. We found that neutrophil-borne cathelicidin (mouse CRAMP, human LL-37) promoted reendothelization and thereby limited neointima formation after stent implantation. We then translated these findings to an animal model using a neutrophil-instructing, biofunctionalized, miniaturized Nitinol stent coated with LL-37. This stent reduced in-stent stenosis in a mouse model of atherosclerosis, suggesting that LL-37 may promote vascular healing after interventional therapy.
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Peptídeos Catiônicos Antimicrobianos/uso terapêutico , Hiperplasia/prevenção & controle , Neointima/prevenção & controle , Neutrófilos/metabolismo , Animais , Peptídeos Catiônicos Antimicrobianos/química , Apolipoproteínas E/genética , Aterosclerose/cirurgia , Células Cultivadas , Stents Farmacológicos , Camundongos , Camundongos Knockout , CatelicidinasAssuntos
Vasos Sanguíneos/metabolismo , Trombose/sangue , Animais , Vasos Sanguíneos/patologia , Micropartículas Derivadas de Células/metabolismo , Congressos como Assunto , Heme Oxigenase (Desciclizante)/metabolismo , Humanos , Fosfatos/metabolismo , Células-Tronco/metabolismo , Tromboplastina/metabolismo , Fator de von Willebrand/metabolismoRESUMO
The chemokines platelet factor 4 (PF4) and RANTES (regulated on activation normal T cell expressed and secreted) are secreted by activated platelets and influence multiple cell types and biologic processes. For instance, PF4 inhibits progenitor cell proliferation and angiogenesis, while platelet-derived RANTES is involved in vascular recruitment of monocytes. However, little is known about functional interactions of PF4 and RANTES. Here we show that the presence of PF4 enhanced the arrest of RANTES-stimulated monocytes and monocytic cells on activated endothelial cells under flow conditions, while binding of PF4 to the monocyte surface was increased by RANTES. Both RANTES-triggered arrest and PF4 binding involved monocytic chondroitin sulfate. Ligand blots and surface plasmon resonance revealed a robust heterophilic interaction of PF4 with RANTES but not with RANTES variants defective in higher order oligomerization. The tetrameric mutant E26A bound to the monocyte surface without increasing PF4 binding, and monocyte arrest induced by E26A-RANTES was not enhanced by PF4. Stimulation of monocytes with supernatants of activated platelets triggered arrest involving RANTES and PF4, as shown by inhibition studies. Our results suggest that heterophilic interactions with PF4 require structural motifs important in RANTES oligomerization and amplify RANTES-triggered effects on monocyte adhesion. This may have implications for the modulation of inflammatory recruitment by platelet-derived chemokines.