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1.
Immunity ; 57(9): 2140-2156.e10, 2024 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-39226900

RESUMO

Venous thromboembolism (VTE) is a common, deadly disease with an increasing incidence despite preventive efforts. Clinical observations have associated elevated antibody concentrations or antibody-based therapies with thrombotic events. However, how antibodies contribute to thrombosis is unknown. Here, we show that reduced blood flow enabled immunoglobulin M (IgM) to bind to FcµR and the polymeric immunoglobulin receptor (pIgR), initiating endothelial activation and platelet recruitment. Subsequently, the procoagulant surface of activated platelets accommodated antigen- and FcγR-independent IgG deposition. This leads to classical complement activation, setting in motion a prothrombotic vicious circle. Key elements of this mechanism were present in humans in the setting of venous stasis as well as in the dysregulated immunothrombosis of COVID-19. This antibody-driven thrombosis can be prevented by pharmacologically targeting complement. Hence, our results uncover antibodies as previously unrecognized central regulators of thrombosis. These findings carry relevance for therapeutic application of antibodies and open innovative avenues to target thrombosis without compromising hemostasis.


Assuntos
Plaquetas , COVID-19 , Ativação do Complemento , Imunoglobulina M , Trombose , Humanos , Trombose/imunologia , Animais , Imunoglobulina M/imunologia , Ativação do Complemento/imunologia , Camundongos , Plaquetas/imunologia , Plaquetas/metabolismo , COVID-19/imunologia , COVID-19/complicações , SARS-CoV-2/imunologia , Proteínas do Sistema Complemento/imunologia , Proteínas do Sistema Complemento/metabolismo , Ativação Plaquetária/imunologia , Imunoglobulina G/imunologia , Masculino
2.
Cell ; 171(6): 1368-1382.e23, 2017 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-29195076

RESUMO

Blood platelets are critical for hemostasis and thrombosis and play diverse roles during immune responses. Despite these versatile tasks in mammalian biology, their skills on a cellular level are deemed limited, mainly consisting in rolling, adhesion, and aggregate formation. Here, we identify an unappreciated asset of platelets and show that adherent platelets use adhesion receptors to mechanically probe the adhesive substrate in their local microenvironment. When actomyosin-dependent traction forces overcome substrate resistance, platelets migrate and pile up the adhesive substrate together with any bound particulate material. They use this ability to act as cellular scavengers, scanning the vascular surface for potential invaders and collecting deposited bacteria. Microbe collection by migrating platelets boosts the activity of professional phagocytes, exacerbating inflammatory tissue injury in sepsis. This assigns platelets a central role in innate immune responses and identifies them as potential targets to dampen inflammatory tissue damage in clinical scenarios of severe systemic infection.


Assuntos
Infecções Bacterianas/imunologia , Plaquetas/imunologia , Animais , Bactérias/classificação , Plaquetas/citologia , Vasos Sanguíneos/lesões , Vasos Sanguíneos/patologia , Cálcio/metabolismo , Movimento Celular , Polaridade Celular , Humanos , Inflamação/imunologia , Integrinas/metabolismo , Camundongos , Miosinas/metabolismo , Neutrófilos/citologia
3.
Immunity ; 55(12): 2285-2299.e7, 2022 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-36272416

RESUMO

Intravascular neutrophils and platelets collaborate in maintaining host integrity, but their interaction can also trigger thrombotic complications. We report here that cooperation between neutrophil and platelet lineages extends to the earliest stages of platelet formation by megakaryocytes in the bone marrow. Using intravital microscopy, we show that neutrophils "plucked" intravascular megakaryocyte extensions, termed proplatelets, to control platelet production. Following CXCR4-CXCL12-dependent migration towards perisinusoidal megakaryocytes, plucking neutrophils actively pulled on proplatelets and triggered myosin light chain and extracellular-signal-regulated kinase activation through reactive oxygen species. By these mechanisms, neutrophils accelerate proplatelet growth and facilitate continuous release of platelets in steady state. Following myocardial infarction, plucking neutrophils drove excessive release of young, reticulated platelets and boosted the risk of recurrent ischemia. Ablation of neutrophil plucking normalized thrombopoiesis and reduced recurrent thrombosis after myocardial infarction and thrombus burden in venous thrombosis. We establish neutrophil plucking as a target to reduce thromboischemic events.


Assuntos
Doenças Cardiovasculares , Infarto do Miocárdio , Trombose , Humanos , Megacariócitos , Trombopoese , Neutrófilos , Plaquetas/fisiologia
4.
Nat Immunol ; 19(6): 606-616, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29777221

RESUMO

Although much is known about the physiological framework of T cell motility, and numerous rate-limiting molecules have been identified through loss-of-function approaches, an integrated functional concept of T cell motility is lacking. Here, we used in vivo precision morphometry together with analysis of cytoskeletal dynamics in vitro to deconstruct the basic mechanisms of T cell migration within lymphatic organs. We show that the contributions of the integrin LFA-1 and the chemokine receptor CCR7 are complementary rather than positioned in a linear pathway, as they are during leukocyte extravasation from the blood vasculature. Our data demonstrate that CCR7 controls cortical actin flows, whereas integrins mediate substrate friction that is sufficient to drive locomotion in the absence of considerable surface adhesions and plasma membrane flux.


Assuntos
Actinas/imunologia , Quimiotaxia de Leucócito/imunologia , Antígeno-1 Associado à Função Linfocitária/imunologia , Receptores CCR7/imunologia , Linfócitos T/imunologia , Actinas/metabolismo , Animais , Quimiocinas/imunologia , Quimiocinas/metabolismo , Fricção , Integrinas/imunologia , Integrinas/metabolismo , Linfonodos , Antígeno-1 Associado à Função Linfocitária/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores CCR7/metabolismo , Linfócitos T/metabolismo
5.
Nature ; 631(8021): 645-653, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38987596

RESUMO

Platelet homeostasis is essential for vascular integrity and immune defence1,2. Although the process of platelet formation by fragmenting megakaryocytes (MKs; thrombopoiesis) has been extensively studied, the cellular and molecular mechanisms required to constantly replenish the pool of MKs by their progenitor cells (megakaryopoiesis) remains unclear3,4. Here we use intravital imaging to track the cellular dynamics of megakaryopoiesis over days. We identify plasmacytoid dendritic cells (pDCs) as homeostatic sensors that monitor the bone marrow for apoptotic MKs and deliver IFNα to the MK niche triggering local on-demand proliferation and maturation of MK progenitors. This pDC-dependent feedback loop is crucial for MK and platelet homeostasis at steady state and under stress. pDCs are best known for their ability to function as vigilant detectors of viral infection5. We show that virus-induced activation of pDCs interferes with their function as homeostatic sensors of megakaryopoiesis. Consequently, activation of pDCs by SARS-CoV-2 leads to excessive megakaryopoiesis. Together, we identify a pDC-dependent homeostatic circuit that involves innate immune sensing and demand-adapted release of inflammatory mediators to maintain homeostasis of the megakaryocytic lineage.


Assuntos
Células Dendríticas , Homeostase , Megacariócitos , Trombopoese , Animais , Feminino , Humanos , Masculino , Camundongos , Apoptose , Plaquetas/citologia , Medula Óssea , Linhagem da Célula , Proliferação de Células , Células Dendríticas/imunologia , Células Dendríticas/citologia , Retroalimentação Fisiológica , Imunidade Inata , Microscopia Intravital , Megacariócitos/citologia , Megacariócitos/imunologia , Camundongos Endogâmicos C57BL , SARS-CoV-2/imunologia , COVID-19/imunologia , COVID-19/fisiopatologia , COVID-19/virologia
6.
Nature ; 582(7813): 582-585, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32581372

RESUMO

Eukaryotic cells migrate by coupling the intracellular force of the actin cytoskeleton to the environment. While force coupling is usually mediated by transmembrane adhesion receptors, especially those of the integrin family, amoeboid cells such as leukocytes can migrate extremely fast despite very low adhesive forces1. Here we show that leukocytes cannot only migrate under low adhesion but can also transmit forces in the complete absence of transmembrane force coupling. When confined within three-dimensional environments, they use the topographical features of the substrate to propel themselves. Here the retrograde flow of the actin cytoskeleton follows the texture of the substrate, creating retrograde shear forces that are sufficient to drive the cell body forwards. Notably, adhesion-dependent and adhesion-independent migration are not mutually exclusive, but rather are variants of the same principle of coupling retrograde actin flow to the environment and thus can potentially operate interchangeably and simultaneously. As adhesion-free migration is independent of the chemical composition of the environment, it renders cells completely autonomous in their locomotive behaviour.


Assuntos
Citoesqueleto de Actina/metabolismo , Movimento Celular , Microambiente Celular , Linfócitos T/citologia , Actinas/metabolismo , Animais , Adesão Celular , Linhagem Celular , Humanos , Camundongos , Linfócitos T/metabolismo , Talina/deficiência
7.
Ann Neurol ; 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-39166769

RESUMO

OBJECTIVE: To assess whether arterial spin labeling perfusion images of healthy controls can enhance ictal single-photon emission computed tomography analysis and whether the acquisition of the interictal image can be omitted. METHODS: We developed 2 pipelines: The first uses ictal and interictal images and compares these to single-photon emission computed tomography and arterial spin labeling of healthy controls. The second pipeline uses only the ictal image and the analogous healthy controls. Both pipelines were compared to the gold standard analysis and evaluated on data of individuals with epilepsy who underwent ictal single-photon emission computed tomography imaging during presurgical evaluation between 2010 and 2022. Fifty healthy controls prospectively underwent arterial spin labeling imaging. The correspondence between the detected hyperperfusion and the postoperative resection cavity or the presumably affected lobe was assessed using Dice score and mean Euclidean distance. Additionally, the outcomes of the pipelines were automatically assigned to 1 of 5 concordance categories. RESULTS: Inclusion criteria were met by 43 individuals who underwent epilepsy surgery and by 73 non-surgical individuals with epilepsy. Compared to the gold standard analysis, both pipelines resulted in significantly higher Dice scores and lower mean distances (p < 0.05). The combination of both provided localizing results in 85/116 cases, compared to 54/116 generated by the current gold standard analysis and the ictal image alone produced localizing results in 60/116 (52%) cases. INTERPRETATION: We propose a new ictal single-photon emission computed tomography protocol; it finds relevantly more ictal hyperperfusion, and halves the radiation dose in about half of the individuals. ANN NEUROL 2024.

8.
Blood ; 141(24): 2973-2992, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-37018659

RESUMO

Platelets are not only the first responders in thrombosis and hemostasis but also central players in inflammation. Compared with platelets recruited to thrombi, immune-responsive platelets use distinct effector functions including actin-related protein complex 2/3-dependent migration along adhesive substrate gradients (haptotaxis), which prevents inflammatory bleeding and contributes to host defense. How platelet migration in this context is regulated on a cellular level is incompletely understood. Here, we use time-resolved morphodynamic profiling of individual platelets to show that migration, in contrast to clot retraction, requires anisotropic myosin IIa-activity at the platelet rear which is preceded by polarized actin polymerization at the front to initiate and maintain migration. Integrin GPIIb-dependent outside-in signaling via Gα13 coordinates polarization of migrating platelets to trigger tyrosine kinase c-Src/14-3-3ζ-dependent lamellipodium formation and functions independent of soluble agonists or chemotactic signals. Inhibitors of this signaling cascade, including the clinically used ABL/c-Src inhibitor dasatinib, interfere predominantly with the migratory capacity of platelets, without major impairment of classical platelet functions. In murine inflammation models, this translates to reduced migration of platelets visualized by 4D intravital microscopy, resulting in increased inflammation-associated hemorrhage in acute lung injury. Finally, platelets isolated from patients with leukemia treated with dasatinib who are prone to clinically relevant hemorrhage exhibit prominent migration defects, whereas other platelet functions are only partially affected. In summary, we define a distinct signaling pathway essential for migration and provide novel mechanistic insights explaining dasatinib-related platelet dysfunction and bleeding.


Assuntos
Plaquetas , Trombose , Humanos , Camundongos , Animais , Plaquetas/metabolismo , Proteínas 14-3-3/metabolismo , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Glicoproteína IIb da Membrana de Plaquetas/metabolismo , Dasatinibe , Actinas/metabolismo , Trombose/metabolismo , Inflamação/metabolismo
9.
Blood ; 140(2): 121-139, 2022 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-35472164

RESUMO

Impairment of vascular integrity is a hallmark of inflammatory diseases. We recently reported that single immune-responsive platelets migrate and reposition themselves to sites of vascular injury to prevent bleeding. However, it remains unclear how single platelets preserve vascular integrity once encountering endothelial breaches. Here we demonstrate by intravital microscopy combined with genetic mouse models that procoagulant activation (PA) of single platelets and subsequent recruitment of the coagulation cascade are crucial for the prevention of inflammatory bleeding. Using a novel lactadherin-based compound, we detect phosphatidylserine (PS)-positive procoagulant platelets in the inflamed vasculature. We identify exposed collagen as the central trigger arresting platelets and initiating subsequent PA in a CypD- and TMEM16F-dependent manner both in vivo and in vitro. Platelet PA promotes binding of the prothrombinase complex to the platelet membrane, greatly enhancing thrombin activity and resulting in fibrin formation. PA of migrating platelets is initiated by costimulation via integrin αIIbß3 (GPIIBIIIA)/Gα13-mediated outside-in signaling and glycoprotein VI signaling, leading to an above-threshold intracellular calcium release. This effectively targets the coagulation cascade to breaches of vascular integrity identified by patrolling platelets. Platelet-specific genetic loss of either CypD or TMEM16F as well as combined blockade of platelet GPIIBIIIA and glycoprotein VI reduce platelet PA in vivo and aggravate pulmonary inflammatory hemorrhage. Our findings illustrate a novel role of procoagulant platelets in the prevention of inflammatory bleeding and provide evidence that PA of patrolling platelet sentinels effectively targets and confines activation of coagulation to breaches of vascular integrity.


Assuntos
Plaquetas , Glicoproteínas da Membrana de Plaquetas , Animais , Plaquetas/metabolismo , Hemorragia/metabolismo , Camundongos , Ativação Plaquetária , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Glicoproteínas da Membrana de Plaquetas/metabolismo
10.
Alzheimers Dement ; 2024 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-39072956

RESUMO

INTRODUCTION: Subjective cognitive decline (SCD) in amyloid-positive (Aß+) individuals was proposed as a clinical indicator of Stage 2 in the Alzheimer's disease (AD) continuum, but this requires further validation across cultures, measures, and recruitment strategies. METHODS: Eight hundred twenty-one participants from SILCODE and DELCODE cohorts, including normal controls (NC) and individuals with SCD recruited from the community or from memory clinics, underwent neuropsychological assessments over up to 6 years. Amyloid positivity was derived from positron emission tomography or plasma biomarkers. Global cognitive change was analyzed using linear mixed-effects models. RESULTS: In the combined and stratified cohorts, Aß+ participants with SCD showed steeper cognitive decline or diminished practice effects compared with NC or Aß- participants with SCD. These findings were confirmed using different operationalizations of SCD and amyloid positivity, and across different SCD recruitment settings. DISCUSSION: Aß+ individuals with SCD in German and Chinese populations showed greater global cognitive decline and could be targeted for interventional trials. HIGHLIGHTS: SCD in amyloid-positive (Aß+) participants predicts a steeper cognitive decline. This finding does not rely on specific SCD or amyloid operationalization. This finding is not specific to SCD patients recruited from memory clinics. This finding is valid in both German and Chinese populations. Aß+ older adults with SCD could be a target population for interventional trials.

11.
BMC Infect Dis ; 23(1): 610, 2023 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-37723464

RESUMO

BACKGROUND: The course of monkeypox can be severe. Our aim was to retrospectively compare the risk of hospital admission, the need for ventilation, sepsis, pneumonitis and death between the recent outbreak and historical outbreaks. MATERIALS AND METHODS: Cases of monkeypox were retrieved from the TriNetX database and assigned to either cohort I (recent outbreak between May 1st and September 16th, 2022) and cohort II (historical outbreaks before May 1st, 2022). After matching for age distribution, statistical analysis was performed. RESULTS: Of 640 patients with monkeypox 81 subjects per cohort remained after matching (mean age±standard deviation = 36.1±18.3 years). Within 56 days after diagnosis 10 patients per cohort were hospitalized (12.4%) and/or developed sepsis (12.4%). The risk of ventilation and pneumonitis were significantly lower among cohort I compared with cohort II (0 vs. 10 cases; risk difference = 12.4%; p = 0.001; Log-Rank test). No cases of death were recorded. CONCLUSION: Even though monkeypox provides a risk of severe courses, the infection is self-limiting in most cases. Unlike past outbreaks, the risk of ventilation and pneumonitis may be relatively low among recent outbreaks.


Assuntos
Mpox , Pneumonia , Sepse , Humanos , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Estudos Retrospectivos , Pneumonia/epidemiologia , Sepse/epidemiologia , Surtos de Doenças , Hospitais
12.
Haematologica ; 107(7): 1669-1680, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34525794

RESUMO

Visualizing cell behavior and effector function on a single cell level has been crucial for understanding key aspects of mammalian biology. Due to their small size, large number and rapid recruitment into thrombi, there is a lack of data on fate and behavior of individual platelets in thrombosis and hemostasis. Here we report the use of platelet lineage restricted multi-color reporter mouse strains to delineate platelet function on a single cell level. We show that genetic labeling allows for single platelet and megakaryocyte (MK) tracking and morphological analysis in vivo and in vitro, while not affecting lineage functions. Using Cre-driven Confetti expression, we provide insights into temporal gene expression patterns as well as spatial clustering of MK in the bone marrow. In the vasculature, shape analysis of activated platelets recruited to thrombi identifies ubiquitous filopodia formation with no evidence of lamellipodia formation. Single cell tracking in complex thrombi reveals prominent myosin-dependent motility of platelets and highlights thrombus formation as a highly dynamic process amenable to modification and intervention of the acto-myosin cytoskeleton. Platelet function assays combining flow cytrometry, as well as in vivo, ex vivo and in vitro imaging show unaltered platelet functions of multicolor reporter mice compared to wild-type controls. In conclusion, platelet lineage multicolor reporter mice prove useful in furthering our understanding of platelet and MK biology on a single cell level.


Assuntos
Megacariócitos , Trombose , Animais , Plaquetas/metabolismo , Medula Óssea/metabolismo , Hemostasia , Mamíferos , Megacariócitos/metabolismo , Camundongos , Trombose/metabolismo
13.
Trends Immunol ; 40(10): 922-938, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31601520

RESUMO

Platelets are central players in thrombosis and hemostasis but are increasingly recognized as key components of the immune system. They shape ensuing immune responses by recruiting leukocytes, and support the development of adaptive immunity. Recent data shed new light on the complex role of platelets in immunity. Here, we summarize experimental and clinical data on the role of platelets in host defense against bacteria. Platelets bind, contain, and kill bacteria directly; however, platelet proinflammatory effector functions and cross-talk with the coagulation system, can also result in damage to the host (e.g., acute lung injury and sepsis). Novel clinical insights support this dichotomy: platelet inhibition/thrombocytopenia can be either harmful or protective, depending on pathophysiological context. Clinical studies are currently addressing this aspect in greater depth.


Assuntos
Lesão Pulmonar Aguda/imunologia , Bactérias/imunologia , Plaquetas/imunologia , Interações Hospedeiro-Patógeno/imunologia , Sepse/imunologia , Imunidade Adaptativa/imunologia , Animais , Humanos
14.
Semin Immunol ; 28(6): 561-569, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27866916

RESUMO

While hemostasis is the physiological process that prevents blood loss after vessel injury, thrombosis is often portrayed as a pathologic event involving blood coagulation and platelet aggregation eventually leading to vascular occlusion and tissue damage. However, recent work suggests that thrombosis can also be a physiological process, termed immunothrombosis, initiated by the innate immune system providing a first line of defense to locally control infection. Fibrin forms the structural basis of immunothrombotic clots and its assembly involves the concerted action of coagulation factors, platelets and leukocytes. Here, we summarize the cellular and molecular events that initiate fibrin formation during the innate immune response and discuss how aberrant activation of these pathways fosters pathologies associated with thrombosis, including disseminated intravascular coagulation and atherothrombosis.


Assuntos
Coagulação Sanguínea , Imunidade Inata , Trombose/sangue , Trombose/etiologia , Animais , Coagulação Sanguínea/imunologia , Fatores de Coagulação Sanguínea/metabolismo , Plaquetas/imunologia , Plaquetas/metabolismo , Fibrina/metabolismo , Hemostasia/imunologia , Interações Hospedeiro-Patógeno/imunologia , Humanos , Leucócitos/imunologia , Leucócitos/metabolismo , Ligação Proteica
15.
Eur J Nucl Med Mol Imaging ; 46(5): 1073-1080, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30474706

RESUMO

BACKGROUND: Data are sparse regarding the feasibility of radioligand therapy (RLT) with [177Lu]Lu-PSMA-617 as a retreatment. We aimed to assess the outcome and safety of rechallenge PSMA-RLT in patients with progressive prostatic cancer who previously benefited from this therapy. MATERIALS AND METHODS: Patients who received rechallenge therapy at our department from January 2015 to March 2018 were assessed. Non-haematological and haematological adverse events were evaluated from laboratory data and clinical reports and were graded according to the Common Terminology Criteria for Adverse Events (CTCAE v. 5.0). Time to prostate-specific-antigen (PSA) progression and the overall survival (OS) rate of the study patients were calculated from the date of the first rechallenge cycle. Furthermore, the OS calculated from the first cycle baseline PSMA-RLT was compared with the survival of patients who received only baseline PSMA-RLT. The response data were determined using [68Ga]Ga-PSMA-PET/CT and measurements of the tumour marker PSA. RESULTS: Included in this retrospective study were 30 patients who were initially treated with a median of 3 cycles (range 1-5) of PSMA-RLT and were eventually retreated after a median of 6 months (range 2-26). Each patient received a median of 3 (range 1-6) rechallenge cycles. None of the patients experienced a disabling or life-threatening grade 4 adverse event according to the Common Toxicity Criteria (CTC). Grade 3 toxicity occurred in 8 patients (27%). Serious adverse events included leucopoenia (n = 2), neutropoenia (n = 1), anaemia (n = 4), thrombopenia (n = 4) and elevated renal parameters (n = 1). Irreversible adverse events occurred in 21 patients (70%). The permanent adverse events were mild/moderate (CTC grade 1/2) in 19 patients and serious (CTC grade 3) in two patients, respectively. According to PSA measurements, 75-90% of patients showed a benefit (response/stable) from the first 4 rechallenge cycles. The median OS was 12 months calculated from the first rechallenge cycle and 25 months calculated from the first cycle baseline PSMA-RLT. For comparison, the median OS in patients who received only baseline PSMA-RLT was 9 months. The difference according to the logrank test was significant: p value <0.001. Patients with a PSA decrease after the first cycle of rechallenge PSMA-RLT survived a median of 19 months, while patients with a PSA increase survived only 6 months. CONCLUSION: Rechallenge prostate-specific membrane antigen (PSMA) therapy has an acceptable safety profile. The majority of the retreated patients benefited from the rechallenge therapy. Patients who showed a biochemical response achieved a longer OS compared to patients who did not respond. The median OS was significantly longer in patients after rechallenge PSMA-RLT than in patients who received only baseline PSMA-RLT.


Assuntos
Dipeptídeos/efeitos adversos , Dipeptídeos/uso terapêutico , Compostos Heterocíclicos com 1 Anel/efeitos adversos , Compostos Heterocíclicos com 1 Anel/uso terapêutico , Neoplasias da Próstata/patologia , Neoplasias da Próstata/radioterapia , Segurança , Idoso , Idoso de 80 Anos ou mais , Estudos de Viabilidade , Humanos , Ligantes , Lutécio , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , Antígeno Prostático Específico , Estudos Retrospectivos , Análise de Sobrevida , Resultado do Tratamento
16.
Eur J Nucl Med Mol Imaging ; 46(5): 1054-1062, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30697649

RESUMO

PURPOSE: To evaluate the use of 68Ga-PSMA PET/CT for monitoring response to 177Lu-617 PSMA radioligand therapy in patients with metastatic castrate-resistant prostate cancer (mCRPC). METHODS: Patients from the University Hospital Bonn and the University Hospital Aachen were retrospectively reviewed for this study. We included 48 patients with mCRPC who were treated with 177Lu-PSMA-617 and whose records included 68Ga-PSMA PET/CT imaging before the first and after the third or fourth treatment cycle. A treatment response based on 68Ga-PSMA PET/CT was defined according to a modified version of the PERCIST criteria. A decline in PSA level of ≥50% was considered the reference standard. The sensitivity, specificity, positive and negative predictive values, and ROC curves were calculated, and patient survival times in relation to the PET results were also analysed. RESULTS: 68Ga-PSMA PET/CT had a sensitivity of about 85% and a specificity of between 55% and 65%. The negative and positive predictive values ranged between 70% and 78%. The fitted ROC area was 0.70. The survival time was about 19.6 months in patients with a treatment response, while nonresponders had a survival time of about 15.9 months. However, this difference between the groups was not statistically significant. CONCLUSION: Our results indicate that 68Ga-PSMA PET/CT could be a useful tool for the evaluation of response to 177Lu-PSMA-617 radioligand therapy within a theranostic framework.


Assuntos
Dipeptídeos/uso terapêutico , Compostos Heterocíclicos com 1 Anel/uso terapêutico , Glicoproteínas de Membrana , Compostos Organometálicos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias de Próstata Resistentes à Castração/diagnóstico por imagem , Neoplasias de Próstata Resistentes à Castração/radioterapia , Idoso , Transporte Biológico , Isótopos de Gálio , Radioisótopos de Gálio , Humanos , Ligantes , Lutécio , Masculino , Glicoproteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Metástase Neoplásica , Compostos Organometálicos/metabolismo , Antígeno Prostático Específico/metabolismo , Neoplasias de Próstata Resistentes à Castração/metabolismo , Neoplasias de Próstata Resistentes à Castração/patologia , Curva ROC , Estudos Retrospectivos , Análise de Sobrevida , Resultado do Tratamento
18.
Blood ; 128(19): 2327-2337, 2016 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-27609642

RESUMO

Under steady-state conditions, aged neutrophils are removed from the circulation in bone marrow, liver, and spleen, thereby maintaining myeloid cell homeostasis. The fate of these aged immune cells under inflammatory conditions, however, remains largely obscure. Here, we demonstrate that in the acute inflammatory response during endotoxemia, aged neutrophils cease returning to the bone marrow and instead rapidly migrate to the site of inflammation. Having arrived in inflamed tissue, aged neutrophils were found to exhibit a higher phagocytic activity as compared with the subsequently recruited nonaged neutrophils. This distinct behavior of aged neutrophils under inflammatory conditions is dependent on specific age-related changes in their molecular repertoire that enable these "experienced" immune cells to instantly translate inflammatory signals into immune responses. In particular, aged neutrophils engage Toll-like receptor-4- and p38 MAPK-dependent pathways to induce conformational changes in ß2 integrins that allow these phagocytes to effectively accomplish their mission in the front line of the inflammatory response. Hence, ageing in the circulation might represent a critical process for neutrophils that enables these immune cells to properly unfold their functional properties for host defense.


Assuntos
Senescência Celular , Inflamação/imunologia , Inflamação/patologia , Neutrófilos/imunologia , Doença Aguda , Animais , Antígeno CD11b/metabolismo , Adesão Celular , Membrana Celular/metabolismo , Rastreamento de Células , Citocinas/metabolismo , Integrinas/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Modelos Biológicos , Fagocitose , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Receptor 4 Toll-Like/metabolismo
19.
Blood ; 128(20): 2435-2449, 2016 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-27574188

RESUMO

Deep venous thrombosis (DVT) is one of the most common cardiovascular diseases, but its pathophysiology remains incompletely understood. Although sterile inflammation has recently been shown to boost coagulation during DVT, the underlying molecular mechanisms are not fully resolved, which could potentially identify new anti-inflammatory approaches to prophylaxis and therapy of DVT. Using a mouse model of venous thrombosis induced by flow reduction in the vena cava inferior, we identified blood-derived high-mobility group box 1 protein (HMGB1), a prototypical mediator of sterile inflammation, to be a master regulator of the prothrombotic cascade involving platelets and myeloid leukocytes fostering occlusive DVT formation. Transfer of platelets into Hmgb1-/- chimeras showed that this cell type is the major source of HMGB1, exposing reduced HMGB1 on their surface upon activation thereby enhancing the recruitment of monocytes. Activated leukocytes in turn support oxidation of HMGB1 unleashing its prothrombotic activity and promoting platelet aggregation. This potentiates the amount of HMGB1 and further nurtures the accumulation and activation of monocytes through receptor for advanced glycation end products (RAGE) and Toll-like receptor 2, leading to local delivery of monocyte-derived tissue factor and cytokines. Moreover, disulfide HMGB1 facilitates formation of prothrombotic neutrophil extracellular traps (NETs) mediated by RAGE, exposing additional HMGB1 on their extracellular DNA strands. Eventually, a vicious circle of coagulation and inflammation is set in motion leading to obstructive DVT formation. Therefore, platelet-derived disulfide HMGB1 is a central mediator of the sterile inflammatory process in venous thrombosis and could be an attractive target for an anti-inflammatory approach for DVT prophylaxis.


Assuntos
Plaquetas/metabolismo , Proteína HMGB1/fisiologia , Trombose Venosa/genética , Animais , Plaquetas/patologia , Dissulfetos/química , Dissulfetos/metabolismo , Proteína HMGB1/química , Proteína HMGB1/genética , Proteína HMGB1/metabolismo , Inflamação/genética , Inflamação/metabolismo , Inflamação/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 88 de Diferenciação Mieloide/genética , Receptor para Produtos Finais de Glicação Avançada/genética , Receptor 2 Toll-Like/genética , Receptor 4 Toll-Like/genética , Trombose Venosa/metabolismo , Trombose Venosa/patologia
20.
Eur J Nucl Med Mol Imaging ; 45(7): 1170-1178, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29468311

RESUMO

PURPOSE: The purpose of our study was to show the feasibility and potential benefits of using 68Ga-PSMA-PET/CT imaging for radiation therapy treatment planning of patients with primary prostate cancer using either integrated boost on the PET-positive volume or localized treatment of the PET-positive volume. The potential gain of such an approach, the improvement of tumor control, and reduction of the dose to organs-at-risk at the same time was analyzed using the QUANTEC biological model. METHODS: Twenty-one prostate cancer patients (70 years average) without previous local therapy received 68Ga-PSMA-PET/CT imaging. Organs-at-risk and standard prostate target volumes were manually defined on the obtained datasets. A PET active volume (PTV_PET) was segmented with a 40% of the maximum activity uptake in the lesion as threshold followed by manual adaption. Five different treatment plan variations were calculated for each patient. Analysis of derived treatment plans was done according to QUANTEC with in-house developed software. Tumor control probability (TCP) and normal tissue complication probability (NTCP) was calculated for all plan variations. RESULTS: Comparing the conventional plans to the plans with integrated boost and plans just treating the PET-positive tumor volume, we found that TCP increased to (95.2 ± 0.5%) for an integrated boost with 75.6 Gy, (98.1 ± 0.3%) for an integrated boost with 80 Gy, (94.7 ± 0.8%) for treatment of PET-positive volume with 75 Gy, and to (99.4 ± 0.1%) for treating PET-positive volume with 95 Gy (all p < 0.0001). For the integrated boost with 80 Gy, a significant increase of the median NTCP of the rectum was found, for all other plans no statistical significant increase in the NTCP neither of the rectum nor the bladder was found. CONCLUSIONS: Our study demonstrates that the use of 68Ga-PSMA-PET/CT image information allows for more individualized prostate treatment planning. TCP values of identified active tumor volumes were increased, while rectum and bladder NTCP values either remained the same or were even lower. However, further studies need to clarify the clinical benefit for the patients applying these techniques.


Assuntos
Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias da Próstata/radioterapia , Radioterapia de Intensidade Modulada , Idoso , Idoso de 80 Anos ou mais , Alemanha , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/diagnóstico por imagem , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Estudos Retrospectivos , Tomografia Computadorizada por Raios X
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