RESUMO
Disruption of the blood-brain barrier and occurrence of coagulopathy after traumatic brain injury (TBI) have important implications for multiple secondary injury processes. Given the extent of post-traumatic changes in neuronal function, significant alterations in some targets, such thrombin (a protease that plays a physiological role in maintaining blood coagulation), play an important role in TBI-induced pathophysiology. Despite the magnitude of thrombin in synaptic plasticity being concentration-dependent, the mechanisms underlying TBI have not been fully elucidated. The understanding of this post-injury neurovascular dysregulation is essential to establish scientific-based rehabilitative strategies. One of these strategies may be supporting physical exercise, considering its relevance in reducing damage after a TBI. However, there are caveats to consider when interpreting the effect of physical exercise on neurovascular dysregulation after TBI. To complete this picture, this review will describe how the interactions established between blood-borne factors (such as thrombin) and physical exercise alter the TBI pathophysiology.
Assuntos
Lesões Encefálicas Traumáticas , Exercício Físico , Trombina , Barreira Hematoencefálica/patologia , Lesões Encefálicas Traumáticas/patologia , Lesões Encefálicas Traumáticas/terapia , Humanos , Plasticidade Neuronal , Trombina/metabolismoRESUMO
Acute respiratory disease caused by a novel coronavirus (SARS-CoV-2) has spread all over the world, since its discovery in 2019, Wuhan, China. This disease is called COVID-19 and already killed over 1 million people worldwide. The clinical symptoms include fever, dry cough, dyspnea, headache, dizziness, generalized weakness, vomiting, and diarrhea. Unfortunately, so far, there is no validated vaccine, and its management consists mainly of supportive care. Venous thrombosis and pulmonary embolism are highly prevalent in patients suffering from severe COVID-19. In fact, a prothrombotic state seems to be present in most fatal cases of the disease. SARS-CoV-2 leads to the production of proinflammatory cytokines, causing immune-mediated tissue damage, disruption of the endothelial barrier, and uncontrolled thrombogenesis. Thrombin is the key regulator of coagulation and fibrin formation. In severe COVID-19, a dysfunctional of physiological anticoagulant mechanisms leads to a progressive increase of thrombin activity, which is associated with acute respiratory distress syndrome development and a poor prognosis. Protease-activated receptor type 1 (PAR1) is the main thrombin receptor and may represent an essential link between coagulation and inflammation in the pathophysiology of COVID-19. In this review, we discuss the potential role of PAR1 inhibition and regulation in COVID-19 treatment.
Assuntos
Coagulação Sanguínea/fisiologia , COVID-19/patologia , Coagulação Intravascular Disseminada/patologia , Receptor PAR-1/metabolismo , Trombina/metabolismo , Anticoagulantes/uso terapêutico , Coagulação Sanguínea/efeitos dos fármacos , Fatores de Coagulação Sanguínea/metabolismo , Coagulação Intravascular Disseminada/tratamento farmacológico , Humanos , Embolia Pulmonar/patologia , Embolia Pulmonar/prevenção & controle , Receptor PAR-1/antagonistas & inibidores , Receptores de Superfície Celular/metabolismo , SARS-CoV-2 , Trombose Venosa/patologia , Trombose Venosa/prevenção & controle , Tratamento Farmacológico da COVID-19RESUMO
Activated Protein C (APC) is a serine-protease that displays antithrombotic and anti-inflammatory properties. In addition, cleavage of protease-activated receptor 1 (PAR1) by APC exerts endothelial cytoprotective actions. The effects of APC on endothelial cells may be reproduced by TR47, a PAR1-based peptide that mimics the novel N-terminus of PAR1 generated upon cleavage at Arg-46 by APC. In this study we demonstrate that wild-type APC and its signaling-proficient mutant, APC-2Cys (which has dramatically reduced anticoagulant activity), display similar inhibitory effects towards the transendothelial migration of A375 human melanoma cells. Consistent with this observation, APC and APC-2Cys significantly reduced the in vivo metastatic potential of the B16F10 murine melanoma cells. TR47 recapitulated the in vitro and in vivo protective profiles of APC and APC-2Cys. Treatment of EA.hy926 endothelial cells with TR47 (20 µM) significantly decreased the A375 cell migration. In addition, treatment of C57/BL6 mice with a single TR47 dose (125 µg/animal) strongly reduced the metastatic burden of B16F10 cells. Together, our results suggest that protection of the endothelial barrier by APC/TR47-mediated signaling pathways might be a valuable therapeutic approach to prevent metastasis.
Assuntos
Movimento Celular/efeitos dos fármacos , Transformação Celular Neoplásica/efeitos dos fármacos , Melanoma/metabolismo , Melanoma/secundário , Peptídeos/administração & dosagem , Receptor PAR-1/química , Animais , Linhagem Celular Tumoral , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Humanos , Melanoma/patologia , Camundongos , Camundongos Endogâmicos C57BL , Invasividade Neoplásica/patologia , Peptídeos/químicaRESUMO
Since the original observations by Bizzozero and Osler, we have seen tremendous advances in the understanding of platelets far beyond haemostasis and the restoration of injured endothelium. In this mini-review on platelets, we will briefly outline their historical description and the importance of their evolution, focusing on a 450 million years old living fossil of Limulus polyphemus, a marine chelicerate arthropod, which helped researchers explain the basis for the immunity role of platelets and make correlations with platelet ultrastructure and function. In addition, the impact of the Limulus Amoebocyte Lysate (LAL) test for modern medicine is highlighted. The role of platelets in cardiovascular diseases, their relevance in arterial and venous thrombosis, and the utilization of antithrombotic drugs as therapeutic agents are also reported. Furthermore, platelet receptors are crucial in aggravating or mitigating other diseases, such as cancer and infections, which can recruit cells and have numerous interactions in a process recently coined "NETosis formation", which is also briefly depicted.
RESUMO
BACKGROUND AND OBJECTIVE: Protease activated receptor type 1 (PAR1 ) seems to play a role in periodontal repair, while PAR2 is associated with periodontal inflammation. As diabetes is a known risk factor for periodontal disease, the aim of this study was to evaluate the influence of type 2 diabetes on PAR1 and PAR2 mRNA expression in the gingival crevicular fluid of patients with chronic periodontitis before and after non-surgical periodontal treatment. MATERIAL AND METHODS: Gingival crevicular fluid samples and clinical parameters consisting of measuring probing depth, clinical attachment level, bleeding on probing and plaque index were collected from systemically healthy patients and patients with type 2 diabetes and chronic periodontitis, at baseline and after non-surgical periodontal therapy. PAR1 and PAR2 , as well as the presence of the proteases RgpB gingipain and neutrophil proteinase-3 were assessed by quantitative polymerase chain reaction in the gingival crevicular fluid. RESULTS: The periodontal clinical parameters significantly improved after periodontal therapy (p < 0.01). Diabetes led to increased expression of PAR1 in gingival crevicular fluid, and in the presence of chronic periodontitis, it significantly decreased the expression of PAR1 and PAR2 (p < 0.05). Moreover, non-surgical periodontal treatment in diabetics resulted in increased expression of PAR1 and PAR2 (p < 0.05), and decreased expression of RgpB gingipain and proteinase-3 (p < 0.05). CONCLUSION: The present data demonstrated that diabetes was associated with an altered expression of PAR1 and PAR2 in the gingival crevicular fluid cells of subjects with chronic periodontitis. Future studies are necessary to elucidate the effects of PAR1 upregulation in periodontally healthy sites and PAR2 downregulation in chronic periodontitis sites on the increased susceptibility and severity of periodontitis in diabetes.
Assuntos
Periodontite Crônica/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Líquido do Sulco Gengival/química , Receptor PAR-1/análise , Receptor PAR-2/análise , Adulto , Periodontite Crônica/complicações , Periodontite Crônica/terapia , Índice de Placa Dentária , Diabetes Mellitus Tipo 2/complicações , Feminino , Fibroblastos/química , Humanos , Masculino , Pessoa de Meia-Idade , Mieloblastina/análise , Mieloblastina/genética , Mieloblastina/metabolismo , Perda da Inserção Periodontal , Bolsa Periodontal , RNA Mensageiro/biossíntese , Receptor PAR-1/genética , Receptor PAR-1/metabolismo , Receptor PAR-2/genética , Receptor PAR-2/metabolismo , Fatores de RiscoRESUMO
The matrix metalloprotease-1 (MMP-1)/protease-activated receptor-1 (PAR-1) signal transduction axis plays an important role in tumorigenesis. To explore the expression and prognostic value of MMP-1 and PAR-1 in esophageal squamous cell carcinoma (ESCC), we evaluated the expression of two proteins in resected specimens from 85 patients with ESCC by immunohistochemistry. Sixty-two (72.9 percent) and 58 (68.2 percent) tumors were MMP-1- and PAR-1-positive, respectively, while no significant staining was observed in normal esophageal squamous epithelium. MMP-1 and PAR-1 overexpression was significantly associated with tumor node metastasis (TNM) stage and regional lymph node involvement. Patients with MMP-1- and PAR-1-positive tumors, respectively, had poorer disease-free survival (DFS) than those with negative ESCC (P = 0.002 and 0.003, respectively). Univariate analysis showed a significant relationship between TNM stage [hazard ratio (HR) = 2.836, 95 percent confidence interval (CI) = 1.866-4.308], regional lymph node involvement (HR = 2.955, 95 percentCI = 1.713-5.068), MMP-1 expression (HR = 2.669, 95 percentCI = 1.229-6.127), and PAR-1 expression (HR = 1.762, 95 percentCI = 1.156-2.883) and DFS. Multivariate analysis including the above four parameters identified TNM stage (HR = 2.035, 95 percentCI = 1.167-3.681), MMP-1 expression (HR = 2.109, 95 percentCI = 1.293-3.279), and PAR-1 expression (HR = 1.967, 95 percentCI = 1.256-2.881) as independent and significant prognostic factors for DFS. Our data suggest for the first time that MMP-1 and PAR-1 were both overexpressed in ESCC and are novel predictors of poor patient prognosis after curative resection. The MMP-1/PAR-1 signal transduction axis might be a new therapeutic target for future therapies tailored against ESCC.