RESUMO
BACKGROUND: We examined how prekallikrein (PK) activation on human microvascular endothelial cells (HMVECs) is regulated by the ambient concentration of C1 inhibitor (C1INH) and prolylcarboxypeptidase (PRCP). OBJECTIVE: We sought to examine the specificity of PK activation on HMVECs by PRCP and the role of C1INH to regulate it, high-molecular-weight kininogen (HK) cleavage, and bradykinin (BK) liberation. METHODS: Investigations were performed on cultured HMVECs. Immunofluorescence, enzymatic activity assays, immunoblots, small interfering RNA knockdowns, and cell transfections were used to perform these studies. RESULTS: Cultured HMVECs constitutively coexpressed PK, HK, C1INH, and PRCP. PK activation on HMVECs was modulated by the ambient C1INH concentration. In the absence of C1INH, forming PKa on HMVECs cleaved 120-kDa HK completely to a 65-kDa H-chain and a 46-kDa L-chain in 60 minutes. In the presence of 2 µM C1INH, only 50% of the HK became cleaved. C1INH concentrations (0.0-2.5 µM) decreased but did not abolish BK liberated from HK by activated PK. Factor XII did not activate when incubated with HMVECs alone for 1 hour. However, if incubated in the presence of HK and PK, factor XII became activated. The specificity of PK activation on HMVECs by PRCP was shown by several inhibitors to each enzyme. Furthermore, PRCP small interfering RNA knockdowns magnified C1INH inhibitory activity on PK activation, and PRCP transfections reduced C1INH inhibition at any given concentration. CONCLUSIONS: These combined studies indicated that on HMVECs, PK activation and HK cleavage to liberate BK were modulated by the local concentrations of C1INH and PRCP.
Assuntos
Fator XII , Pré-Calicreína , Humanos , Células Endoteliais , Bradicinina/farmacologia , Cininogênio de Alto Peso Molecular , RNA Interferente Pequeno/genéticaRESUMO
As per the classical view of the coagulation system, it functions solely in plasma to maintain hemostasis. An experimental approach modeling vascular reconstitution was used to show that vascular endothelial cells (ECs) endogenously synthesize coagulation factors during angiogenesis. Intracellular thrombin generated from this synthesis promotes the mitotic function of vascular endothelial cell growth factor A (VEGF-A). The thrombin concurrently cleaves C5a from EC-synthesized complement component C5 and unmasks the tethered ligand for EC-expressed protease-activated receptor 4 (PAR4). The two ligands jointly trigger EC C5a receptor-1 (C5ar1) and PAR4 signaling, which together promote VEGF receptor 2 growth signaling. C5ar1 is functionally associated with PAR4, enabling C5a or thrombin to elicit Gαi and/or Gαq signaling. EC coagulation factor and EC complement component synthesis concurrently down-regulate with contact inhibition. The connection of these processes with VEGF receptor 2 signaling provides new insights into mechanisms underlying angiogenesis. Knowledge of endogenous coagulation factor/complement component synthesis and joint PAR4/C5ar1 signaling could be applied to other cell types.
Assuntos
Fatores de Coagulação Sanguínea/biossíntese , Células Endoteliais/metabolismo , Neovascularização Fisiológica , Receptor da Anafilatoxina C5a/metabolismo , Receptores Ativados por Proteinase/metabolismo , Transdução de Sinais , Animais , Fatores de Coagulação Sanguínea/genética , Feminino , Masculino , Camundongos , Camundongos Knockout , Receptor da Anafilatoxina C5a/genética , Receptores Ativados por Proteinase/genéticaRESUMO
Since the outbreak of COVID-19 disease, a bidirectional interaction between kidney disease and the progression of COVID-19 has been demonstrated. Kidney disease is an independent risk factor for mortality of patients with COVID-19 as well as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leading to the development of acute kidney injury (AKI) and chronic kidney disease (CKD) in patients with COVID-19. However, the detection of kidney damage in patients with COVID-19 may not occur until an advanced stage based on the current clinical blood and urinary examinations. Some studies have pointed out the development of subclinical acute kidney injury (subAKI) syndrome with COVID-19. This syndrome is characterized by significant tubule interstitial injury without changes in the estimated glomerular filtration rate. Despite the complexity of the mechanism(s) underlying the development of subAKI, the involvement of changes in the protein endocytosis machinery in proximal tubule (PT) epithelial cells (PTECs) has been proposed. This paper focuses on the data relating to subAKI and COVID-19 and the role of PTECs and their protein endocytosis machinery in its pathogenesis.
Assuntos
Injúria Renal Aguda , COVID-19 , Insuficiência Renal Crônica , Humanos , COVID-19/complicações , SARS-CoV-2 , Injúria Renal Aguda/metabolismo , Insuficiência Renal Crônica/metabolismo , Túbulos Renais Proximais/metabolismoRESUMO
OBJECTIVE: Management of carotid artery stenosis (CAS) remains controversial and proper patient selection critical. Elevated neutrophil to lymphocyte ratio (NLR) has been associated with poor outcomes after vascular procedures. The effect of NLR on outcomes after carotid endarterectomy (CEA) in asymptomatic and symptomatic patients is assessed. MATERIALS AND METHODS: A retrospective review was conducted of all patients between 2010 and 2018 with carotid stenosis >70% as defined by CREST 2 criteria. A total of 922 patients were identified, of whom 806 were treated with CEA and 116 non-operatively with best medical therapy (BMT). Of patients undergoing CEA, 401 patients (290 asymptomatic [aCEA], 111 symptomatic [sCEA]) also had an available NLR calculated from a complete blood count with differential. All patients treated with BMT were asymptomatic and had a baseline NLR available. Kaplan-Meier analysis assessed composite ipsilateral stroke or death over 3 years. RESULTS: In sCEA group, the 3-year composite stroke/death rates did not differ between NLR < 3.0 (22.9%) vs NLR > 3.0 (38.1%) (P=.10). In aCEA group, patients with a baseline NLR >3.0 had an increased risk of 3-year stroke/death (42.6%) compared to both those with NLR <3.0 (9.3%, P<.0001) and those treated with BMT (23.6%, P=.003). In patients with NLR <3.0, aCEA showed a superior benefit over BMT with regard to stroke or death (9.3% vs. 26.2%, P=.02). However, in patients with NLR >3.0, there was no longer a benefit to prophylactic CEA compared to BMT (42.6% vs. 22.2%, P=.05). Multivariable analysis identified NLR >3.0 (HR, 3.23; 95% CI, 1.93-5.42; P<.001) and congestive heart failure (HR, 2.18; 95% CI, 1.33-3.58; P=.002) as independent risk factors for stroke/death in patients with asymptomatic carotid artery stenosis. CONCLUSIONS: NLR >3.0 is associated with an increased risk of late stroke/death after prophylactic CEA for asymptomatic carotid artery stenosis, with benefits not superior to BMT. NLR may be used to help with selecting asymptomatic patients for CEA. The effect of NLR and outcomes in symptomatic patients requires further study. Better understanding of the mechanism(s) for NLR elevation and medical intervention strategies are needed to modulate outcome risk in these patients.
Assuntos
Estenose das Carótidas , Endarterectomia das Carótidas , Linfócitos , Neutrófilos , Estenose das Carótidas/sangue , Estenose das Carótidas/cirurgia , Endarterectomia das Carótidas/efeitos adversos , Humanos , Estudos Retrospectivos , Fatores de Risco , Resultado do TratamentoRESUMO
A new form of severe acute respiratory syndrome (SARS) caused by SARS-coronavirus 2 (CoV-2), called COVID-19, has become a global threat in 2020. The mortality rate from COVID-19 is high in hypertensive patients, making this association especially dangerous. There appears to be a consensus, despite the lack of experimental data, that angiotensin II (ANG II) is linked to the pathogenesis of COVID-19. This process may occur due to acquired deficiency of angiotensin-converting enzyme 2 (ACE2), resulting in reduced degradation of ANG II. Furthermore, ANG II has a critical role in the genesis and worsening of hypertension. In this context, the idea that there is a surge in the level of ANG II with COVID-19 infection, causing multiple organ injuries in hypertensive patients becomes attractive. However, the role of other components of the renin angiotensin system (RAS) in this scenario requires elucidation. The identification of other RAS components in COVID-19 hypertension may provide both diagnostic and therapeutic benefits. Here, we summarize the pathophysiologic contributions of different components of RAS in hypertension and their possible correlation with poor outcome observed in hypertensive patients with COVID-19.
Assuntos
Infecções por Coronavirus/fisiopatologia , Hipertensão/fisiopatologia , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/fisiopatologia , Sistema Renina-Angiotensina/fisiologia , Angiotensina II/metabolismo , Enzima de Conversão de Angiotensina 2 , Betacoronavirus , COVID-19 , Infecções por Coronavirus/mortalidade , Humanos , Hipertensão/mortalidade , Pandemias , Pneumonia Viral/mortalidade , Fatores de Risco , SARS-CoV-2RESUMO
OBJECTIVE: The neutrophil-lymphocyte ratio (NLR) is an inexpensive and useful inflammatory marker that incorporates the balance of the innate (neutrophil) and adaptive (lymphocyte) immune responses. Data exist on the association between NLR and mortality in various coronary diseases and in cancer surgery, but there is a paucity of data on the impact of preoperative NLR on vascular surgical outcomes. The aim of this study was to evaluate the relationship between preoperative NLR and elective endovascular aortic aneurysm repair (EVAR) outcome. METHODS: A retrospective review of all patients who underwent elective EVAR at a single institution between 2010 and 2018 was conducted (n = 373). Only patients who had a preoperative complete blood count with differential within 30 days of their operation were included. The NLR was computed by dividing the absolute neutrophil count by the absolute lymphocyte count. A receiver operating characteristic curve was used to determine the optimal cutoff value of NLR with the strongest association with mortality. NLR was dichotomized so that patients with NLR above the threshold were at increased risk of mortality compared with those below it. Continuous variables were analyzed using Wilcoxon nonparametric signed-rank test and categorical variables with the Fisher exact test. A comparison of NLR and mortality was completed using Kaplan-Meier survival analysis. Cox regression analysis was used to evaluate factors associated with mortality through 5-year follow-up. RESULTS: Overall, 108 patients were included in this study. An NLR ≥ 4.0 was found to be associated with mortality (P < .0001). Thirty-two patients composed the High-NLR (NLR ≥ 4.0) group and the remaining 76 patients formed the Low-NLR (NLR < 4.0) group. Baseline characteristics were similar between groups, except that the High-NLR group was older (77.9 vs 74.4; P = .047). At a mean of 36.4 months follow-up, the overall mortality rate was 32.4%. Although there were no differences in the perioperative period, the Kaplan-Meier estimates of mortality were significantly greater in the High-NLR group at 1, 2, and 5 years postoperatively (P < .0001). The mean preoperative NLR of the deceased was higher (5.94 ± 5.20; median, 4.75; interquartile range, 3.17-7.83) than those who survived (2.87 ± 1.61; median, 2.53; interquartile range, 1.97-3.49) (P < .0001). Secondary interventions and sac enlargement rates were similar between groups. On univariable analysis, NLR (hazard ratio [HR], 1.17; 95% confidence interval [CI], 1.10-1.23; P < .0001), age (HR, 1.06; 95% CI, 1.02-1.11; P = .004), and aneurysm diameter (HR, 1.04; 95% CI, 1.01-1.07; P = .003) were associated with mortality. On multivariable analysis, NLR (HR, 1.19; 95% CI, 1.12-1.27; P < .0001), age (HR, 1.06; 95% CI, 1.01-1.11; P = .026), and aneurysm diameter (HR, 1.04; 95% CI, 1.02-1.07; P = .003) were associated with mortality. CONCLUSIONS: Patients with an elevated preoperative NLR, irrespective of other comorbidities, may represent a previously unrecognized subset of patients who are at heightened risk of mortality after elective EVAR. A complete blood count with differential is an inexpensive test that may be used as a prognostic indicator for outcome after EVAR. Further research is warranted to identify clinical, pathological, or anatomical factors associated with an elevated NLR and to determine modifiable factors, which may help improve long-term survival.
Assuntos
Aneurisma da Aorta Abdominal/cirurgia , Procedimentos Endovasculares/mortalidade , Inflamação/mortalidade , Linfócitos , Neutrófilos , Idoso , Idoso de 80 Anos ou mais , Aneurisma da Aorta Abdominal/sangue , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Aneurisma da Aorta Abdominal/mortalidade , Procedimentos Endovasculares/efeitos adversos , Feminino , Humanos , Inflamação/sangue , Inflamação/diagnóstico , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do TratamentoRESUMO
BACKGROUND: Antibodies against factor VIII (FVIII), seen in acquired (AHA) and congenital haemophilia A, lead to severe bleeding diatheses. Current first-line treatment includes bypass agents. Recombinant porcine sequence FVIII (rpFVIII) was developed as an alternative therapy. AIM: To describe our institutional experience with the use of rpFVIII. METHODS: A retrospective chart review of five patients treated with rpVIII between 2016 and 2019. RESULTS: Five patients (four AHA, one congenital haemophilia with inhibitors) were treated with rpFVIII. No patient had an adverse event during infusion. All patients initially exhibited a response evidenced by increased FVIII levels from baseline <1% to 81%-170%, normalization of the activated partial thromboplastin time (aPTT) and resolution of bleeding. However, all five patients were subsequently noted to have decreasing peak FVIII levels and aPTT prolongation, either within the initial treatment course or upon later re-administration. Resistance to rpFVIII was recognized after an average of 12.4 exposure days. Porcine FVIII inhibitor levels measured afterwards were present (detectable-170 Bethesda units) in all patients. Three out of four AHA subjects also developed an increase in the anti-human FVIII inhibitor titres after receiving rpFVIII. CONCLUSION: rpFVIII was safe and initially effective in all patients. However, its use is associated with development of an inhibitor to rpFVIII, decreasing its efficacy and duration of effect. Further, rpFVIII use may lead to an increase in patient anti-human FVIII inhibitor titres. A larger study is necessary to appropriately assess the incidence of these outcomes.
Assuntos
Fator VIII/antagonistas & inibidores , Hemofilia A/terapia , Proteínas Recombinantes/farmacologia , Adulto , Idoso , Animais , Autoanticorpos/imunologia , Testes de Coagulação Sanguínea/métodos , Fator VIII/química , Fator VIII/imunologia , Feminino , Hemofilia A/genética , Hemofilia A/imunologia , Hemorragia/prevenção & controle , Humanos , Infusões Intravenosas , Masculino , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/uso terapêutico , Estudos Retrospectivos , Segurança , Suínos , Resultado do TratamentoRESUMO
The risk of thrombosis, a globally growing challenge and a major cause of death, is influenced by various factors in the intravascular coagulation, vessel wall, and cellular systems. Among the contributors to thrombosis, the contact activation system and the kallikrein/kinin system, two overlapping plasma proteolytic systems that are often considered as synonymous, regulate thrombosis from different aspects. On one hand, components of the contact activation system such as factor XII initiates activation of the coagulation proteins promoting thrombus formation on artificial surfaces through factor XI- and possibly prekallikrein-mediated intrinsic coagulation. On the other hand, physiological activation of plasma prekallikrein in the kallikrein/kinin system on endothelial cells liberates bradykinin from associated high-molecular-weight kininogen to stimulate the constitutive bradykinin B2 receptor to generate nitric oxide and prostacyclin to induce vasodilation and counterbalance angiotensin II signaling from the renin-angiotensin system which stimulates vasoconstriction. In addition to vascular tone regulation, this interaction between the kallikrein/kinin and renin-angiotensin systems has a thrombo-regulatory role independent of the contact pathway. At the level of the G-protein coupled receptors of these systems, defective bradykinin signaling due to attenuated bradykinin formation and/or decreased B2 receptor expression, as seen in murine prekallikrein and B2 receptor null mice, respectively, leads to compensatory overexpressed Mas, the receptor for angiotensin-(1-7) of the renin-angiotensin system. Mas stimulation and/or its increased expression contributes to maintaining a healthy vascular homeostasis by generating graded elevation of plasma prostacyclin which reduces thrombosis through two independent pathways: (1) increasing the vasoprotective transcription factor Sirtuin 1 to suppress tissue factor expression, and (2) inhibiting platelet activation. This review will summarize the recent advances in this field that support these understandings. Appreciating these subtle mechanisms help to develop novel anti-thrombotic strategies by targeting the vascular receptors in the renin-angiotensin and the kallikrein/kinin systems to maintain healthy vascular homeostasis.
Assuntos
Coagulação Sanguínea , Sistema Calicreína-Cinina/efeitos dos fármacos , Proteínas Proto-Oncogênicas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Sistema Renina-Angiotensina , Trombose/sangue , Animais , Epoprostenol/metabolismo , Humanos , Pré-Calicreína/metabolismo , Proto-Oncogene Mas , Receptor B2 da Bradicinina/metabolismo , Transdução de Sinais , Sirtuína 1/metabolismoRESUMO
Abl1 kinase has important biological roles. The Bcr-Abl1 fusion protein creates undesired kinase activity and is pathogenic in 95% of chronic myeloid leukemia (CML) and 30% of acute lymphoblastic leukemia (ALL) patients. Targeted therapies to these diseases are tyrosine kinase inhibitors. The extent of a tyrosine kinase inhibitor's targets determines the degree of biologic effects of the agent that may influence the well-being of the patient. This fact is especially true with tyrosine kinase inhibitor effects on the cardiovascular system. Thirty-one percent of ponatinib-treated patients, the tyrosine kinase inhibitor with the broadest inhibitory spectrum, have thrombosis associated with its use. Recent experimental investigations have indicated the mechanisms of ponatinib-associated thrombosis. Further, an antidote to ponatinib is in development by re-purposing an FDA-approved medication.
Assuntos
Imidazóis/uso terapêutico , Piridazinas/uso terapêutico , Trombose/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Proteínas de Fusão bcr-abl/genética , Humanos , Imidazóis/efeitos adversos , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Piridazinas/efeitos adversosRESUMO
Objective- Terminal complications of bacterial sepsis include development of disseminated intravascular consumptive coagulopathy. Bacterial constituents, including long-chain polyphosphates (polyP), have been shown to activate the contact pathway of coagulation in plasma. Recent work shows that activation of the contact pathway in flowing whole blood promotes thrombin generation and platelet activation and consumption distal to thrombus formation ex vivo and in vivo. Here, we sought to determine whether presence of long-chain polyP or bacteria in the bloodstream promotes platelet activation and consumption in a coagulation factor (F)XII-dependent manner. Approach and Results- Long-chain polyP promoted platelet P-selectin expression, microaggregate formation, and platelet consumption in flowing whole blood in a contact activation pathway-dependent manner. Moreover, long-chain polyP promoted local fibrin formation on collagen under shear flow in a FXI-dependent manner. Distal to the site of thrombus formation, platelet consumption was dramatically enhanced in the presence of long-chain polyP in the blood flow in a FXI- and FXII-dependent manner. In a murine model, long-chain polyP promoted platelet deposition and fibrin generation in lungs in a FXII-dependent manner. In a nonhuman primate model of bacterial sepsis, pre-treatment of animals with an antibody blocking FXI activation by FXIIa reduced lethal dose100 Staphylococcus aureus-induced platelet and fibrinogen consumption. Conclusions- This study demonstrates that bacterial-type long-chain polyP promotes platelet activation in a FXII-dependent manner in flowing blood, which may contribute to sepsis-associated thrombotic processes, consumptive coagulopathy, and thrombocytopenia.
Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Plaquetas/efeitos dos fármacos , Fator XII/metabolismo , Fator XIIa/metabolismo , Ativação Plaquetária/efeitos dos fármacos , Polifosfatos/toxicidade , Trombose/induzido quimicamente , Animais , Plaquetas/metabolismo , Modelos Animais de Doenças , Fator XII/genética , Fator XIIa/genética , Feminino , Fibrina/metabolismo , Humanos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Papio ursinus , Pré-Calicreína/genética , Pré-Calicreína/metabolismo , Embolia Pulmonar/sangue , Embolia Pulmonar/induzido quimicamente , Embolia Pulmonar/genética , Sepse/sangue , Sepse/microbiologia , Transdução de Sinais/efeitos dos fármacos , Infecções Estafilocócicas/sangue , Infecções Estafilocócicas/microbiologia , Trombose/sangue , Trombose/genética , Calicreínas Teciduais/genética , Calicreínas Teciduais/metabolismoRESUMO
The precise mechanism for reduced thrombosis in prekallikrein null mice (Klkb1(-/-)) is unknown. Klkb1(-/-) mice have delayed carotid artery occlusion times on the rose bengal and ferric chloride thrombosis models. Klkb1(-/-) plasmas have long-activated partial thromboplastin times and defective contact activation-induced thrombin generation that partially corrects upon prolonged incubation. However, in contact activation-induced pulmonary thromboembolism by collagen/epinephrine or long-chain polyphosphate, Klkb1(-/-) mice, unlike F12(-/-) mice, do not have survival advantage. Klkb1(-/-) mice have reduced plasma BK levels and renal B2R mRNA. They also have increased expression of the renal receptor Mas and plasma prostacyclin. Increased prostacyclin is associated with elevated aortic vasculoprotective transcription factors Sirt1 and KLF4. Treatment of Klkb1(-/-) mice with the Mas antagonist A-779, COX-2 inhibitor nimesulide, or Sirt1 inhibitor splitomicin lowers plasma prostacyclin and normalizes arterial thrombosis times. Treatment of normal mice with the Mas agonist AVE0991 reduces thrombosis. Klkb1(-/-) mice have reduced aortic tissue factor (TF) mRNA, antigen, and activity. In sum, Klkb1(-/-) mice have a novel mechanism for thrombosis protection in addition to reduced contact activation. This pathway arises when bradykinin delivery to vasculature is compromised and mediated by increased receptor Mas, prostacyclin, Sirt1, and KLF4, leading to reduced vascular TF.
Assuntos
Trombose das Artérias Carótidas , Epoprostenol , Fatores de Transcrição Kruppel-Like , Pré-Calicreína , Proteínas Proto-Oncogênicas , Receptores Acoplados a Proteínas G , Tromboplastina , Angiotensina II/análogos & derivados , Angiotensina II/farmacologia , Animais , Trombose das Artérias Carótidas/induzido quimicamente , Trombose das Artérias Carótidas/genética , Trombose das Artérias Carótidas/metabolismo , Trombose das Artérias Carótidas/patologia , Epoprostenol/biossíntese , Epoprostenol/genética , Imidazóis/farmacologia , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/antagonistas & inibidores , Fatores de Transcrição Kruppel-Like/biossíntese , Fatores de Transcrição Kruppel-Like/genética , Camundongos , Camundongos Knockout , Naftalenos/farmacologia , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/genética , Tempo de Tromboplastina Parcial , Fragmentos de Peptídeos/farmacologia , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Pironas/farmacologia , RNA Mensageiro , Receptor B2 da Bradicinina/biossíntese , Receptor B2 da Bradicinina/genética , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Sirtuína 1/antagonistas & inibidores , Sirtuína 1/biossíntese , Sirtuína 1/genética , Sulfonamidas/farmacologia , Sinaptotagminas/biossíntese , Sinaptotagminas/genética , Tromboplastina/antagonistas & inibidores , Tromboplastina/biossíntese , Tromboplastina/genéticaRESUMO
PURPOSE OF REVIEW: This report examines the mechanism(s) by which each protein of the contact activation system - factor XII (FXII), high-molecular-weight kininogen, and prekallikrein - influences thrombosis risk. RECENT FINDINGS: FXII generates thrombin through contact activation via interaction with artificial surfaces as on medical instruments such as indwelling catheters, mechanical valves, stents, and ventricular assist devices. Inhibition of FXIIa-mediated contact activation prevents thrombosis under contact activation circumstances without affecting hemostasis. Current studies suggest that high-molecular-weight kininogen deficiency parallels that of FXII and inhibits contact activation. Prekallikrein inhibition contributes to thrombosis prevention by contact activation inhibition in the nylon monofilament model of transient middle cerebral artery occlusion. However, in arterial thrombosis models where reactive oxygen species are generated, prekallikrein deficiency results in downregulation of vessel wall tissue factor generation with reduced thrombin generation. Exploiting this latter prekallikrein pathway for thrombosis risk reduction provides a general, overall reduced tissue factor, antithrombotic pathway without risk for bleeding. SUMMARY: These investigations indicate that the proteins of the contact activation and kallikrein/kinin systems influence thrombosis risk by several mechanisms and understanding of these pathway provides insight into several novel targets to prevent thrombosis without increase in bleeding risk.
Assuntos
Coagulação Sanguínea , Transdução de Sinais , Trombose/metabolismo , Animais , Biomarcadores , Ativação Enzimática , Fator XII/antagonistas & inibidores , Fator XII/genética , Fator XII/metabolismo , Humanos , Cininogênio de Alto Peso Molecular/genética , Cininogênio de Alto Peso Molecular/metabolismo , Leucócitos/metabolismo , Pré-Calicreína/genética , Pré-Calicreína/metabolismo , Ligação Proteica , Trombose/sangue , Trombose/genética , Trombose/prevenção & controleRESUMO
Multiple myeloma confers a high risk for vascular thrombosis, a risk that is increased by treatment with immunomodulatory agents. Strikingly, inclusion of the proteasome inhibitor bortezomib reduces thrombotic risk, yet the molecular basis for this observation remains unknown. Here, we show that bortezomib prolongs thrombosis times in the carotid artery photochemical injury assay in normal mice. Cell-based studies show that bortezomib increases expression of the transcription factor Kruppel-like factor 2 (KLF2) in multiple cell types. Global postnatal overexpression of KLF2 (GL-K2-TG) increased time to thrombosis, and global postnatal deletion of KLF2 (GL-K2-KO) conferred an antiparallel effect. Finally, studies in GL-K2-KO mice showed that the thromboprotective effect of bortezomib is KLF2 dependent. These findings identify a transcriptional basis for the antithrombotic effects of bortezomib.
Assuntos
Ácidos Borônicos/farmacologia , Trombose das Artérias Carótidas/prevenção & controle , Citoproteção/genética , Fatores de Transcrição Kruppel-Like/fisiologia , Pirazinas/farmacologia , Animais , Bortezomib , Trombose das Artérias Carótidas/sangue , Trombose das Artérias Carótidas/genética , Trombose das Artérias Carótidas/patologia , Células Cultivadas , Oclusão Coronária/genética , Oclusão Coronária/patologia , Oclusão Coronária/prevenção & controle , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Fatores de Transcrição Kruppel-Like/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Tempo de Coagulação do Sangue TotalRESUMO
Prolylcarboxypeptidase (PRCP) is associated with leanness, hypertension, and thrombosis. PRCP-depleted mice have injured vessels with reduced Kruppel-like factor (KLF)2, KLF4, endothelial nitric oxide synthase (eNOS), and thrombomodulin. Does PRCP influence vessel growth, angiogenesis, and injury repair? PRCP depletion reduced endothelial cell growth, whereas transfection of hPRCP cDNA enhanced cell proliferation. Transfection of hPRCP cDNA, or an active site mutant (hPRCPmut) rescued reduced cell growth after PRCP siRNA knockdown. PRCP-depleted cells migrated less on scratch assay and murine PRCP(gt/gt) aortic segments had reduced sprouting. Matrigel plugs in PRCP(gt/gt) mice had reduced hemoglobin content and angiogenic capillaries by platelet endothelial cell adhesion molecule (PECAM) and NG2 immunohistochemistry. Skin wounds on PRCP(gt/gt) mice had delayed closure and reepithelialization with reduced PECAM staining, but increased macrophage infiltration. After limb ischemia, PRCP(gt/gt) mice also had reduced reperfusion of the femoral artery and angiogenesis. On femoral artery wire injury, PRCP(gt/gt) mice had increased neointimal formation, CD45 staining, and Ki-67 expression. Alternatively, combined PRCP(gt/gt) and MRP-14(-/-) mice were protected from wire injury with less neointimal thickening, leukocyte infiltration, and cellular proliferation. PRCP regulates cell growth, angiogenesis, and the response to vascular injury. Combined with its known roles in blood pressure and thrombosis control, PRCP is positioned as a key regulator of vascular homeostasis.
Assuntos
Carboxipeptidases/fisiologia , Células Endoteliais/enzimologia , Neovascularização Patológica , Neovascularização Fisiológica , Animais , Aorta/metabolismo , Apoptose , Calgranulina B/metabolismo , Bovinos , Movimento Celular , Proliferação de Células , Células Cultivadas , Artéria Femoral/patologia , Células Endoteliais da Veia Umbilical Humana , Humanos , Isquemia/patologia , Antígeno Ki-67/metabolismo , Fator 4 Semelhante a Kruppel , Camundongos , Camundongos Endogâmicos C57BL , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , CicatrizaçãoRESUMO
Bradykinin B2 receptor-deleted mice (Bdkrb2(-/-)) have delayed carotid artery thrombosis times and prolonged tail bleeding time resulting from elevated angiotensin II (AngII) and angiotensin receptor 2 (AT2R) producing increased plasma nitric oxide (NO) and prostacyclin. Bdkrb2(-/-) also have elevated plasma angiotensin-(1-7) and messenger RNA and protein for its receptor Mas. Blockade of Mas with its antagonist A-779 in Bdkrb2(-/-) shortens thrombosis times (58 ± 4 minutes to 38 ± 4 minutes) and bleeding times (170 ± 13 seconds to 88 ± 8 seconds) and lowers plasma nitrate (22 ± 4 µM to 15 ± 5 µM), and 6-keto-PGF1α (259 ± 103 pg/mL to 132 ± 58 pg/mL). Bdkrb2(-/-) platelets express increased NO, guanosine 3',5'-cyclic monophosphate, and cyclic adenosine monophosphate with reduced spreading on collagen, collagen peptide GFOGER, or fibrinogen. In vivo A-779 or combined L-NAME and nimesulide treatment corrects it. Bdkrb2(-/-) platelets have reduced collagen-related peptide-induced integrin α2bß3 activation and P-selectin expression that are partially corrected by in vivo A-779, nimesulide, or L-NAME. Bone marrow transplantations show that the platelet phenotype and thrombosis time depends on the host rather than donor bone marrow progenitors. Transplantation of wild-type bone marrow into Bdkrb2(-/-) hosts produces platelets with a spreading defect and delayed thrombosis times. In Bdkrb2(-/-), combined AT2R and Mas overexpression produce elevated plasma prostacyclin and NO leading to acquired platelet function defects and thrombosis delay.
Assuntos
Angiotensina I/sangue , Plaquetas/metabolismo , Epoprostenol/sangue , Óxido Nítrico/sangue , Fragmentos de Peptídeos/sangue , Glicoproteínas da Membrana de Plaquetas/metabolismo , Proteínas Proto-Oncogênicas/sangue , Receptores Acoplados a Proteínas G/sangue , Angiotensina II/análogos & derivados , Angiotensina II/farmacologia , Animais , Tempo de Sangramento , Plaquetas/efeitos dos fármacos , Transplante de Medula Óssea , AMP Cíclico/sangue , GMP Cíclico/sangue , Immunoblotting , Camundongos , Camundongos da Linhagem 129 , Camundongos Knockout , NG-Nitroarginina Metil Éster/farmacologia , Fragmentos de Peptídeos/farmacologia , Inibidores da Agregação Plaquetária/farmacologia , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/genética , Receptor Tipo 2 de Angiotensina/sangue , Receptor B2 da Bradicinina/deficiência , Receptor B2 da Bradicinina/genética , Receptores Acoplados a Proteínas G/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sulfonamidas/farmacologia , Trombose/sangue , Fatores de TempoAssuntos
Coagulação Sanguínea , COVID-19/virologia , SARS-CoV-2/patogenicidade , Trombose/virologia , Anticoagulantes/uso terapêutico , Coagulação Sanguínea/efeitos dos fármacos , COVID-19/sangue , COVID-19/diagnóstico , Interações Hospedeiro-Patógeno , Humanos , Fatores de Risco , Trombose/sangue , Trombose/diagnóstico , Trombose/prevenção & controle , Tratamento Farmacológico da COVID-19RESUMO
Coagulation factor XII (FXII, Hageman factor, EC = 3.4.21.38) is the zymogen of the serine protease, factor XIIa (FXIIa). FXII is converted to FXIIa through autoactivation induced by "contact" to charged surfaces. FXIIa is of crucial importance for fibrin formation in vitro, but deficiency in the protease is not associated with excessive bleeding. For decades, FXII was considered to have no function for coagulation in vivo. Our laboratory developed the first murine knockout model of FXII. Consistent with their human counterparts, FXII(-/-) mice have a normal hemostatic capacity. However, thrombus formation in FXII(-/-) mice is largely defective, and the animals are protected from experimental cerebral ischemia and pulmonary embolism. This murine model has created new interest in FXII because it raises the possibility for safe anticoagulation, which targets thrombosis without influence on hemostasis. We recently have identified platelet polyphosphate (an inorganic polymer) and mast cell heparin as in vivo FXII activators with implications on the initiation of thrombosis and edema during hypersensitivity reactions. Independent of its protease activity, FXII exerts mitogenic activity with implications for angiogenesis. The goal of this review is to summarize the in vivo functions of FXII, with special focus to its functions in thrombosis and vascular biology.
Assuntos
Coagulação Sanguínea/genética , Fator XII/fisiologia , Animais , Coagulação Sanguínea/fisiologia , Vasos Sanguíneos/metabolismo , Vasos Sanguíneos/fisiologia , Fator XII/genética , Fator XII/metabolismo , Hemostasia/genética , Hemostasia/fisiologia , Humanos , Inflamação/sangue , Inflamação/etiologia , Inflamação/genética , Camundongos , Camundongos Knockout , Modelos Biológicos , Trombose/sangue , Trombose/etiologia , Trombose/genéticaRESUMO
It is well-established that dysfunction of megalin-mediated albumin endocytosis by proximal tubule epithelial cells (PTECs) and the activation of the Renin-Angiotensin System (RAS) play significant roles in the development of Diabetic Kidney Disease (DKD). However, the precise correlation between these factors still requires further investigation. In this study, we aimed to elucidate the potential role of angiotensin II (Ang II), a known effector of RAS, as the mediator of albumin endocytosis dysfunction induced by high glucose (HG) in PTECs. To achieve this, we utilized LLC-PK1 and HK-2 cells, which are well-established in vitro models of PTECs. Using albumin-FITC or DQ-albumin as tracers, we observed that incubation of LLC-PK1 and HK-2 cells with HG (25 mM for 48 h) significantly reduced canonical receptor-mediated albumin endocytosis, primarily due to the decrease in megalin expression. HG increased the concentration of Ang II in the LLC-PK1 cell supernatant, a phenomenon associated with an increase in angiotensin-converting enzyme (ACE) expression and a decrease in prolyl carboxypeptidase (PRCP) expression. ACE type 2 (ACE2) expression remained unchanged. To investigate the potential impact of Ang II on HG effects, the cells were co-incubated with angiotensin receptor inhibitors. Only co-incubation with 10-7 M losartan (an antagonist for type 1 angiotensin receptor, AT1R) attenuated the inhibitory effect of HG on albumin endocytosis, as well as megalin expression. Our findings contribute to understanding the genesis of tubular albuminuria observed in the early stages of DKD, which involves the activation of the Ang II/AT1R axis by HG.