Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 14.617
Filtrar
1.
PLoS Comput Biol ; 18(9): e1010414, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36107837

RESUMO

Thrombin is an enzyme produced during blood coagulation that is crucial to the formation of a stable clot. Thrombin cleaves soluble fibrinogen into fibrin, which polymerizes and forms an insoluble, stabilizing gel around the growing clot. A small fraction of circulating fibrinogen is the variant γA/γ', which has been associated with high-affinity thrombin binding and implicated as a risk factor for myocardial infarctions, deep vein thrombosis, and coronary artery disease. Thrombin is also known to be strongly sequestered by polymerized fibrin for extended periods of time in a way that is partially regulated by γA/γ'. However, the role of γA/γ'-thrombin interactions during fibrin polymerization is not fully understood. Here, we present a mathematical model of fibrin polymerization that considered the interactions between thrombin, fibrinogen, and fibrin, including those with γA/γ'. In our model, bivalent thrombin-fibrin binding greatly increased thrombin residency times and allowed for thrombin-trapping during fibrin polymerization. Results from the model showed that early in fibrin polymerization, γ' binding to thrombin served to localize the thrombin to the fibrin(ogen), which effectively enhanced the enzymatic conversion of fibrinogen to fibrin. When all the fibrin was fully generated, however, the fibrin-thrombin binding persisted but the effect of fibrin on thrombin switched quickly to serve as a sink, essentially removing all free thrombin from the system. This dual role for γ'-thrombin binding during polymerization led to a paradoxical decrease in trapped thrombin as the amount of γ' was increased. The model highlighted biochemical and biophysical roles for fibrin-thrombin interactions during polymerization and agreed well with experimental observations.


Assuntos
Fibrina , Trombina , Fibrina/metabolismo , Fibrinogênio/metabolismo , Modelos Teóricos , Polimerização , Trombina/metabolismo
2.
Int J Implant Dent ; 8(1): 36, 2022 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-36098849

RESUMO

PURPOSE: Platelet-rich fibrin (PRF) has been proposed as promising biomaterials with the advantages of host accumulation of platelets and leukocytes with entrapment of growth factors and fibrin scaffold. However, limitations including fast resorption rate (~ 2 weeks) restricts its clinical application. Recent studies have demonstrated heating treatment can prolong PRF degradation. Current published articles used the method of 75 °C for 10 min to obtain longer degradation, while few studies investigated the most suitable temperature for heating horizontal PRF. Our present study was to discover and confirm the optimum temperature for heat treatment before obtaining H-PRF gels by investigating their structure, mechanical properties, and bioactivity of the H-PRF gels after heating treatment. METHODS: In the present study, 2-mL upper layer of horizontal PRF was collected and heated at 45 °C, 60 °C, 75 °C, and 90 °C to heat 2-mL upper layer of horizontal PRF for 10 min before mixing with the 2-mL lower layer horizontal PRF. The weight, solidification time and the degradation properties were subsequently recorded. Scanning electron microscopy (SEM) and rheologic tests were carried out to investigate the microstructure and rheologic properties of each H-PRF gel. The biological activity of each H-PRF gel was also evaluated using live/dead staining. RESULTS: H-PRF gel prepared at 75 °C for 10 min had the fast solidification period (over a tenfold increase than control) as well as the best resistance to degradation. The number of living cells in H-PRF gel is greater than 90%. SEM showed that H-PRF gel becomes denser as the heating temperature increases, and rheologic tests also revealed that the heat treatment improved the mechanical properties of H-PRF gels when compared to non-heated control group. Future clinical studies are needed to further support the clinical application of H-PRF gels in tissue regeneration procedures. CONCLUSIONS: Our results demonstrated that the H-PRF gel obtained at 75 °C for 10 min could produce a uniform, moldable gel with a short time for solidification time, great rheologic behavior and, high percent of live cells in PRF gel. A promising use of the commonly utilized PRF gel was achieved facilitating tissue regeneration and preventing degradation.


Assuntos
Fibrina , Fibrina Rica em Plaquetas , Plaquetas , Fibrina/análise , Géis/análise , Calefação , Fibrina Rica em Plaquetas/química , Temperatura
3.
Trials ; 23(1): 774, 2022 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-36104785

RESUMO

BACKGROUND: COVID-19 pneumonia is associated with the development of acute respiratory distress syndrome (ARDS) displaying some typical histological features. These include diffuse alveolar damage with extensive pulmonary coagulation activation. This results in fibrin deposition in the microvasculature, leading to the formation of hyaline membranes in the air sacs. Well-conducted clinical trials have found that nebulised heparin limits pulmonary fibrin deposition, attenuates progression of ARDS, hastens recovery and is safe in non-COVID ARDS. Unfractionated heparin also inactivates the SARS-CoV-2 virus and prevents entry into mammalian cells. Nebulisation of heparin may therefore limit fibrin-mediated lung injury and inhibit pulmonary infection by SARS-CoV-2. Based on these findings, we designed the CHARTER-Ireland Study, a phase 1b/2a randomised controlled study of nebulised heparin in patients requiring advanced respiratory support for COVID-19 pneumonia. METHODS: This is a multi-centre, phase 1b/IIa, randomised, parallel-group, open-label study. The study will randomise 40 SARs-CoV-2-positive patients receiving advanced respiratory support in a critical care area. Randomisation will be via 1:1 allocation to usual care plus nebulised unfractionated heparin 6 hourly to day 10 while receiving advanced respiratory support or usual care only. The study aims to evaluate whether unfractionated heparin will decrease the procoagulant response associated with ARDS up to day 10. The study will also assess safety and tolerability of nebulised heparin as defined by number of severe adverse events; oxygen index and respiratory oxygenation index of intubated and unintubated, respectively; ventilatory ratio; and plasma concentration of interleukin (IL)-1ß, IL6, IL-8, IL-10 and soluble tumour necrosis factor receptor 1, C-reactive protein, procalcitonin, ferritin, fibrinogen and lactate dehydrogenase as well as the ratios of IL-1ß/IL-10 and IL-6/IL-10. These parameters will be assessed on days 1, 3, 5 and 10; time to separation from advanced respiratory support, time to discharge from the intensive care unit and number tracheostomised to day 28; and survival to days 28 and 60 and to hospital discharge, censored at day 60. Some clinical outcome data from our study will be included in the international meta-trials, CHARTER and INHALE-HEP. DISCUSSION: This trial aims to provide evidence of potential therapeutic benefit while establishing safety of nebulised heparin in the management of ARDS associated with SARs-CoV-2 infection. TRIAL REGISTRATION: ClinicalTrials.gov NCT04511923 . Registered on 13 August 2020. Protocol version 8, 22/12/2021 Protocol identifier: NUIG-2020-003 EudraCT registration number: 2020-003349-12 9 October 2020.


Assuntos
Lesão Pulmonar Aguda , COVID-19 , Síndrome do Desconforto Respiratório , Lesão Pulmonar Aguda/diagnóstico , Lesão Pulmonar Aguda/etiologia , Animais , Fibrina , Heparina/efeitos adversos , Humanos , Interleucina-10 , Irlanda , Mamíferos , Estudos Multicêntricos como Assunto , Ensaios Clínicos Controlados Aleatórios como Assunto , Síndrome do Desconforto Respiratório/diagnóstico , Síndrome do Desconforto Respiratório/tratamento farmacológico , SARS-CoV-2
4.
Int J Mol Sci ; 23(17)2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-36077276

RESUMO

Articular cartilage is a highly organized tissue that provides remarkable load-bearing and low friction properties, allowing for smooth movement of diarthrodial joints; however, due to the avascular, aneural, and non-lymphatic characteristics of cartilage, joint cartilage has self-regeneration and repair limitations. Cartilage tissue engineering is a promising alternative for chondral defect repair. It proposes models that mimic natural tissue structure through the use of cells, scaffolds, and signaling factors to repair, replace, maintain, or improve the specific function of the tissue. In chondral tissue engineering, fibrin is a biocompatible biomaterial suitable for cell growth and differentiation with adequate properties to regenerate damaged cartilage. Additionally, its mechanical, biological, and physical properties can be enhanced by combining it with other materials or biological components. This review addresses the biological, physical, and mechanical properties of fibrin as a biomaterial for cartilage tissue engineering and as an element to enhance the regeneration or repair of chondral lesions.


Assuntos
Cartilagem Articular , Fibrina , Materiais Biocompatíveis/química , Cartilagem Articular/patologia , Engenharia Tecidual , Tecidos Suporte/química
5.
Int J Mol Sci ; 23(17)2022 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-36077472

RESUMO

The eukaryotic initiation factor 4E binding protein (4E-BP) family is involved in translational control of cell proliferation and pro-angiogenic factors. The zebrafish eukaryotic initiation factor 4E binding protein 3 like (eif4ebp3l) is a member of the 4E-BPs and responsible for activity-dependent myofibrillogenesis, but whether it affects cardiomyocyte (CM) proliferation or heart regeneration is unclear. We examined eif4ebp3l during zebrafish vascular development and heart regeneration post cryoinjury in adult zebrafish. Using morpholino injections we induced silencing of eif4ebp3l in zebrafish embryos, which led to increased angiogenesis at 94 h post fertilization (hpf). For investigation of eif4ebp3l in cardiac regeneration, zebrafish hearts were subjected to cryoinjury. Regenerating hearts were analyzed at different time points post-cryoinjury for expression of eif4ebp3l by in situ hybridization and showed strongly decreased eif4ebp3l expression in the injured area. We established a transgenic zebrafish strain, which overexpressed eif4ebp3l under the control of a heat-shock dependent promotor. Overexpression of eif4ebp3l during zebrafish heart regeneration caused only macroscopically a reduced amount of fibrin at the site of injury. Overall, these findings demonstrate that silencing of eif4ebp3l has pro-angiogenic properties in zebrafish vascular development and when eif4ebp3l is overexpressed, fibrin deposition tends to be altered in zebrafish cardiac regeneration after cryoinjury.


Assuntos
Fator de Iniciação 4E em Eucariotos , Peixe-Zebra , Animais , Proliferação de Células , Fator de Iniciação 4E em Eucariotos/genética , Fator de Iniciação 4E em Eucariotos/metabolismo , Fibrina/metabolismo , Coração , Miócitos Cardíacos/metabolismo , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
6.
Cells ; 11(17)2022 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-36078030

RESUMO

Background: Titanium (Ti) is one of the most popular implant materials, and its surface titanium dioxide (TiO2) provides good biocompatibility. The coagulation of blood on Ti implants plays a key role in wound healing and cell growth at the implant site; however, researchers have yet to fully elucidate the mechanism underlying this process on TiO2. Methods: This study examined the means by which blood coagulation was affected by the crystal structure of TiO2 thin films (thickness < 50 nm), including anatase, rutile, and mixed anatase/rutile. The films were characterized in terms of roughness using an atomic force microscope, thickness using an X-ray photoelectron spectrometer, and crystal structure using transmission electron microscopy. The surface energy and dielectric constant of the surface films were measured using a contact angle goniometer and the parallel plate method, respectively. Blood coagulation properties (including clotting time, factor XII contact activation, fibrinogen adsorption, fibrin attachment, and platelet adhesion) were then assessed on the various test specimens. Results: All of the TiO2 films were similar in terms of surface roughness, thickness, and surface energy (hydrophilicity); however, the presence of rutile structures was associated with a higher dielectric constant, which induced the activation of factor XII, the formation of fibrin network, and platelet adhesion. Conclusions: This study provides detailed information related to the effects of TiO2 crystal structures on blood coagulation properties on Ti implant surfaces.


Assuntos
Fator XII , Titânio , Coagulação Sanguínea , Fibrina , Propriedades de Superfície , Titânio/química
7.
Contrast Media Mol Imaging ; 2022: 3464042, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36072631

RESUMO

The aim of this study was to investigate imaging features of magnetic resonance imaging (MRI), pathological features of thrombus, and expression of nucleotide-binding oligomerization domain-like receptors protein 3 (NLRP3) inflammasome in acute ischemic stroke (AIS). Their relationship with the prognosis of patients was also explored. Sixty patients with AIS admitted to the hospital were selected as the observation group, and 20 healthy objects were in the control group. The shape of the thrombus was observed by MRI, pathological features of the thrombus were observed under hematoxylin-eosin (HE) staining, and the levels of NLRP3 inflammasome and inflammatory factors in serum were detected. The MRI-T2 weighted imaging (T2WI) signal ratio and plaque enhancement rate in the observation group were higher than those in the control group significantly (P < 0.05). In the observation group, the red/mixed thrombus in 6-12 h and 24 h were also much higher than that in 6 h (P < 0.05). The levels of NLRP3, interleukin-1ß (IL-1ß), interleukin-18 (IL-18), and tumor necrosis factor-α (TNF-α) in the observation group were higher than those in the control group in 6 h, 6-12 h, and 24 h (P < 0.05), and those reached the highest levels in 24 h. The ratio of fibrins/platelets in the cardiogenic thrombus reached (63.8 ± 15.6) %, which was significantly higher than that in the large-artery atherosclerotic thrombus (49.5 ± 14.2) %, P < 0.05. The ratio of red blood cells (RBCs) in the large atherosclerotic thrombus was (30.7 ± 14.3) %, considerably lower than (42.9 ± 15.2) %, P < 0.05. The prognosis of patients with the fibrin/platelet-rich thrombus was highly lower than that with the RBC-rich thrombus (P < 0.05). The levels with poor prognosis were higher than those with good prognosis (P < 0.05). MRI could be used to assist in the assessment of brain conditions in patients with AIS. NLRP3 inflammasome was involved in the inflammatory response of AIS and can be used for predicting the poor prognosis, having a certain clinical application value. In addition, different types of thrombi also laid a certain impact on prognosis.


Assuntos
Aterosclerose , AVC Isquêmico , Trombose , Fibrina , Humanos , Inflamassomos , AVC Isquêmico/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Proteína 3 que Contém Domínio de Pirina da Família NLR , Trombose/diagnóstico por imagem , Trombose/patologia
8.
World J Gastroenterol ; 28(26): 3132-3149, 2022 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-36051331

RESUMO

BACKGROUND: The development of venous thromboembolism (VTE) is associated with high mortality among gastric cancer (GC) patients. Neutrophil extracellular traps (NETs) have been reported to correlate with the prothrombotic state in some diseases, but are rarely reported in GC patients. AIM: To investigate the effect of NETs on the development of cancer-associated thrombosis in GC patients. METHODS: The levels of NETs in blood and tissue samples of patients were analyzed by ELISA, flow cytometry, and immunofluorescence staining. NET generation and hypercoagulation of platelets and endothelial cells (ECs) in vitro were observed by immunofluorescence staining. NET procoagulant activity (PCA) was determined by fibrin formation and thrombin-antithrombin complex (TAT) assays. Thrombosis in vivo was measured in a murine model induced by flow stenosis in the inferior vena cava (IVC). RESULTS: NETs were likely to form in blood and tissue samples of GC patients compared with healthy individuals. In vitro studies showed that GC cells and their conditioned medium, but not gastric mucosal epithelial cells, stimulated NET release from neutrophils. In addition, NETs induced a hypercoagulable state of platelets by upregulating the expression of phosphatidylserine and P-selectin on the cells. Furthermore, NETs stimulated the adhesion of normal platelets on glass surfaces. Similarly, NETs triggered the conversion of ECs to hypercoagulable phenotypes by downregulating the expression of their intercellular tight junctions but upregulating that of tissue factor. Treatment of normal platelets or ECs with NETs augmented the level of plasma fibrin formation and the TAT complex. In the models of IVC stenosis, tumor-bearing mice showed a stronger ability to form thrombi, and NETs abundantly accumulated in the thrombi of tumor-bearing mice compared with control mice. Notably, the combination of deoxyribonuclease I, activated protein C, and sivelestat markedly abolished the PCA of NETs. CONCLUSION: GC-induced NETs strongly increased the risk of VTE development both in vitro and in vivo. NETs are potential therapeutic targets in the prevention and treatment of VTE in GC patients.


Assuntos
Armadilhas Extracelulares , Neoplasias Gástricas , Trombofilia , Trombose , Tromboembolia Venosa , Animais , Constrição Patológica , Células Endoteliais/metabolismo , Armadilhas Extracelulares/metabolismo , Fibrina , Camundongos , Neutrófilos/metabolismo , Neoplasias Gástricas/complicações , Neoplasias Gástricas/metabolismo , Trombose/etiologia , Tromboembolia Venosa/etiologia , Tromboembolia Venosa/metabolismo
9.
Infect Dis Obstet Gynecol ; 2022: 8061112, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36046178

RESUMO

Background: Vertical transmission of several viruses during pregnancy has been shown to cause adverse fetal outcomes. The question about the possibility of a similar outcome in association with SARS-CoV-2 has been raised in recently published articles. Indeed, the rate of transmission through the placenta to the fetus reported in women with COVID-19 has been shown to form a minority. The aim of this study was to explore the possible histopathological changes in the placenta of pregnant women with COVID-19 after delivery and those changes in the umbilical cord. Methods: A case-control study including a total of 50 full-term pregnant women with COVID-19 and 60 control pregnant females. Histopathological evaluation of placental tissues and umbilical cords were reported. Results: The main findings in the umbilical cord were increased thickness of vessels, thrombus formation, endothelins, and narrow lumen; except for the increased thickness of blood vessels, these findings were more frequently seen in women with COVID-19, in comparison with control women in a significant manner (p < 0.05). Increased thickness of blood vessels was more significantly observed in the control group compared to the COVID-19 group (p < 0.01). Findings of the placenta included avascular villi, fibrin, thrombosis, and meconium macrophage in various combinations. Except for fibrin as the sole findings, all other findings including combinations were more frequently encountered in the study group in comparison to the control group (p < 0.05). Conclusion: Pregnant women with COVID-19 have significant pathological alterations in the placenta and umbilical cord. These findings reflect the capability of SARS-CoV-2 in causing immunological reactions to the placenta, either directly or indirectly, and these pathologies may be linked to the higher rate of adverse neonatal outcomes and maternal admission to the intensive care unit.


Assuntos
COVID-19 , Complicações Infecciosas na Gravidez , Estudos de Casos e Controles , Feminino , Fibrina , Humanos , Recém-Nascido , Transmissão Vertical de Doenças Infecciosas , Placenta/patologia , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Resultado da Gravidez , Gestantes , SARS-CoV-2
10.
Biosens Bioelectron ; 216: 114659, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36095979

RESUMO

Pesticide residues have raised serious public concern towards agriculture, environment and food safety. Recently, metal-organic frameworks (MOFs) have been employed as promising recognition and signal generation elements in sensors for pesticide detection. However, the general format of tiny particles with poor dispersity brings obstacles to detection operation and the improvement of sensing performance. Here, we report a sensor based on porous MOFs hybrid sponge for fluorescent-visible detection of methyl parathion. Benefiting from the intermediate of adhesive and porous fibrin film, MOFs are loaded with good dispersion and accessibility, thereby endowing the sensor with a rapid response time of 10-min, a wide linear detection range of 50-2500 µg L-1, and a low limit of detection of 4.95 µg L-1. Moreover, the hybrid sensor presented superior durability and anti-interference ability to the detection in complex conditions, including organic solvents, acidic solution, high temperature, and even chemical interferences. This hybrid not only provides a new construction strategy for a nanomaterial-based sensor, but also permits a portable and durable route for the detection.


Assuntos
Técnicas Biossensoriais , Estruturas Metalorgânicas , Metil Paration , Resíduos de Praguicidas , Praguicidas , Fibrina , Estruturas Metalorgânicas/química , Compostos Organofosforados , Porosidade , Solventes
11.
Artigo em Inglês | MEDLINE | ID: mdl-36053207

RESUMO

Tumours or tumour-like lesions around the aortic valve are relatively rare and are difficult to diagnose. We report an interesting case of calcified thrombi in the Valsalva sinuses and coronary cusps that mimicked an aortic valve tumour. A 68-year-old man presented with a 20-mm calcified mass in the non-coronary and left-coronary cusps extending to their corresponding Valsalva sinuses, which was detected by echocardiography and contrast-enhanced computed tomography. The lesions were resected to establish the diagnosis and prevent systemic embolization. Intraoperative and histopathological examination revealed an atrophied non-coronary leaflet and calcified atherosclerotic lesions of the Valsalva sinuses and contiguous parts of the cusps, with ulceration and fibrin thrombi. The lesions were resected and aortic valve replacement was performed to avoid aortic valve dysfunction. The patient's atrial fibrillation was controlled, and anticoagulants were discontinued 3 months postoperatively. Surgery to establish the diagnosis and to prevent systemic thromboembolism was thought to be reasonable, even in the absence of valvular dysfunction.


Assuntos
Neoplasias , Seio Aórtico , Trombose , Idoso , Anticoagulantes , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/cirurgia , Fibrina , Humanos , Masculino , Seio Aórtico/diagnóstico por imagem , Seio Aórtico/cirurgia , Trombose/diagnóstico por imagem , Trombose/patologia , Trombose/cirurgia
12.
Nutrients ; 14(17)2022 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-36079810

RESUMO

Although fibrinolytic enzymes and thrombolytic agents help in cardiovascular disease treatment, those currently available have several side effects. This warrants the search for safer alternatives. Several natural cysteine protease preparations are used in traditional medicine to improve platelet aggregation and thrombosis-related diseases. Hence, this study aimed to investigate the effect of ficin, a natural cysteine protease, on fibrin(ogen) and blood coagulation. The optimal pH (pH 7) and temperature (37 °C) for proteolytic activity were determined using the azocasein method. Fibrinogen action and fibrinolytic activity were measured both electrophoretically and by the fibrin plate assay. The effect of ficin on blood coagulation was studied by conventional coagulation tests: prothrombin time (PT), activated partial thromboplastin time (aPTT), blood clot lysis assay, and the κ-carrageenan thrombosis model. The Aα, Bß, and γ bands of fibrinogen are readily cleaved by ficin, and we also observed a significant increase in PT and aPTT. Further, the mean length of the infarcted regions in the tails of Sprague-Dawley rats was shorter in rats administered 10 U/mL of ficin than in control rats. These findings suggest that natural cysteine protease, ficin contains novel fibrin and fibrinogenolytic enzymes and can be used for preventing and/or treating thrombosis-associated cardiovascular disorders.


Assuntos
Cisteína Proteases , Trombose , Animais , Anticoagulantes/farmacologia , Carragenina , Cisteína Proteases/uso terapêutico , Estrona/análogos & derivados , Fibrina/uso terapêutico , Fibrinogênio , Fibrinolíticos/farmacologia , Fibrinolíticos/uso terapêutico , Ficina , Ratos , Ratos Sprague-Dawley , Trombose/tratamento farmacológico
13.
J Comp Pathol ; 197: 44-52, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36089296

RESUMO

The objective of this study was to evaluate critically the nature and prevalence of histological pulmonary lesions in dogs and cats that had died or were euthanized because of tick paralysis. A retrospective and prospective case study of 11 cats and 23 dogs was carried out. Retrospective cases were gathered from the Veterinary Laboratory Services database at The University of Queensland (UQ). Prospective cases were provided by Veterinary Specialist Services and UQ VETs Small Animal Hospital. Lung and other tissue samples were collected for histopathological analysis. All tick intoxicated animals demonstrated evidence of pulmonary parenchymal changes: alveolar oedema, interstitial and alveolar congestion and alveolar fibrin exudation. Eleven of 23 (48%) dogs exhibited mild to severe bronchopneumonia. A lower rate (18%) of bronchopneumonia was found in cats, with one case of aspiration pneumonia. A novel pulmonary histological grading scheme was developed to evaluate the correlation between clinical presentation and histopathological changes. Novel extrapulmonary lesions in cats included hepatic necrosis and acute renal tubular necrosis attributed to hypoxia. We concluded that both dogs and cats with high clinical grade tick paralysis are extremely likely to have pulmonary pathology. High-protein oedema and fibrin exudation are predicted to be present in most cases of canine and feline tick paralysis.


Assuntos
Broncopneumonia , Doenças do Gato , Doenças do Cão , Paralisia por Carrapato , Animais , Broncopneumonia/veterinária , Doenças do Gato/patologia , Gatos , Doenças do Cão/patologia , Cães , Fibrina , Pulmão/patologia , Necrose/veterinária , Estudos Retrospectivos , Paralisia por Carrapato/epidemiologia , Paralisia por Carrapato/patologia , Paralisia por Carrapato/veterinária
14.
Clin Epigenetics ; 14(1): 117, 2022 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-36127710

RESUMO

BACKGROUND: DNA 5-hydroxymethylcytosine (5hmC) is produced by dynamic 5mC oxidation process contributing to tissue specification, and loss of 5hmC has been reported in multiple cancers including genitourinary cancers. However, 5hmC is also cell-type specific, and its variability may exist between differentiated tumor cells and cancer stem cells. Thus, cancer-associated changes in 5hmC may be contributed by distinct sets of tumor cells within the tumor tissues. RESULTS: Here, we applied a sensitive immunoprecipitation-based method (hMeDIP-seq) to analyze 5hmC changes during genitourinary carcinogenesis (including prostate, urothelial and kidney). We confirmed the tissue-specific distribution of 5hmC in genitourinary tissues and identified regional gain and global loss of 5hmC coexisting in genitourinary cancers. The genes with gain of 5hmC during tumorigenesis were functionally enriched in regulating stemness and hypoxia, whereas were associated with poor clinical prognosis irrespective of their differences in tumor type. We identified that gain of 5hmC occurred in soft fibrin gel-induced 3D tumor spheres with a tumor-repopulating phenotype in two prostate cancer cell lines, 22RV1 and PC3, compared with conventional two-dimensional (2D) rigid dishes. Then, we defined a malignant signature derived from the differentially hydroxymethylated regions affected genes of cancer stem-like cells, which could predict a worse clinical outcome and identified phenotypically malignant populations of cells from prostate cancer tumors. Notably, an oxidation-resistant vitamin C derivative, ascorbyl phosphate magnesium, restored 5hmC and killed the cancer stem cell-like cells leading to apoptosis in prostate cancer cell lines. CONCLUSIONS: Collectively, our study dissects the regional gain of 5hmC in maintaining cancer stem-like cells and related to poor prognosis, which provides proof of concept for an epigenetic differentiation therapy with vitamin C by 5hmC reprogramming.


Assuntos
Neoplasias da Próstata , Neoplasias Urogenitais , 5-Metilcitosina/análogos & derivados , Ácido Ascórbico/farmacologia , Carcinogênese , DNA/metabolismo , Metilação de DNA , Fibrina/metabolismo , Humanos , Magnésio , Masculino , Fosfatos , Neoplasias da Próstata/genética , Neoplasias Urogenitais/genética
15.
Cardiovasc Diabetol ; 21(1): 190, 2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36131342

RESUMO

BACKGROUND: Post-acute sequelae of COVID-19 (PASC), also now known as long COVID, has become a major global health and economic burden. Previously, we provided evidence that there is a significant insoluble fibrin amyloid microclot load in the circulation of individuals with long COVID, and that these microclots entrap a substantial number of inflammatory molecules, including those that might prevent clot breakdown. Scientifically, the most challenging aspect of this debilitating condition is that traditional pathology tests such as a serum CRP (C-reactive protein) may not show any significant abnormal inflammatory markers, albeit these tests measure only the soluble inflammatory molecules. Elevated, or abnormal soluble biomarkers such as IL-6, D-Dimer or fibrinogen indicate an increased risk for thrombosis or a host immune response in COVID-19. The absence of biomarkers in standard pathology tests, result in a significant amount of confusion for patients and clinicians, as patients are extremely sick or even bed-ridden but with no regular identifiable reason for their disease. Biomarkers that are currently available cannot detect the molecules present in the microclots we identified and are therefore unable to confirm their presence or the mechanisms that drive their formation. METHODS: Here we analysed the protein content of double-digested microclots of 99 long COVID patients and 29 healthy controls. The patients suffering from long COVID reported their symptoms through a questionnaire completed by themselves or their attending physician. RESULTS: Our long COVID cohort's symptoms were found to be in line with global findings, where the most prevalent symptoms were constant fatigue (74%,) cognitive impairment (71%) and depression and anxiety (30%). Our most noteworthy findings were a reduced level of plasma Kallikrein compared to our controls, an increased level of platelet factor 4 (PF4) von Willebrand factor (VWF), and a marginally increased level of α-2 antiplasmin (α-2-AP). We also found a significant presence of antibodies entrapped inside these microclots. CONCLUSION: Our results confirm the presence of pro-inflammatory molecules that may also contribute to a failed fibrinolysis phenomenon, which could possibly explain why individuals with long COVID suffer from chronic fatigue, dyspnoea, or cognitive impairment. In addition, significant platelet hyperactivation was noted. Hyperactivation will result in the granular content of platelets being shed into the circulation, including PF4. Overall, our results provide further evidence of both a failed fibrinolytic system in long COVID/PASC and the entrapment of many proteins whose presence might otherwise go unrecorded. These findings might have significant implications for individuals with pre-existing comorbidities, including cardiovascular disease and type 2 diabetes.


Assuntos
COVID-19 , Diabetes Mellitus Tipo 2 , Trombose , Biomarcadores , Proteína C-Reativa/metabolismo , COVID-19/complicações , Diabetes Mellitus Tipo 2/complicações , Fibrina/metabolismo , Fibrinogênio/metabolismo , Humanos , Interleucina-6 , Calicreína Plasmática , Fator Plaquetário 4 , Proteômica , Trombose/diagnóstico , alfa 2-Antiplasmina , Fator de von Willebrand/análise
16.
Thromb Res ; 218: 112-129, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36037547

RESUMO

The collagen receptor glycoprotein VI (GPVI) drives strong platelet activation, however its role at later stages of clotting remains less clear. Controlled timing of addition of anti-human GPVI Fab (clone E12) with microfluidic venous whole blood flow over collagen (± lipidated tissue factor, TF) produced distinct effects on platelets, fibrin, P-selectin exposure, and phosphatidylserine (PS) exposure. On collagen alone, Fab present initially potently reduced platelet deposition on collagen, while Fab added 90 s after initial platelet deposition, stopped subsequent platelet accumulation (despite the absence of fibrin). With thrombin generation via TF, Fab added at either t = 0 or 90 s had no effect on platelet deposition. However, Fab added initially, but not at 90-s, blocked fibrin formation. Gly-Pro-Arg-Pro ablated fibrin formation without effect on platelet accumulation (regardless of Fab added at t = 0 or 90 s), indicating thrombin signaling can suffice over GPVI signaling. Still, Fab moderately reduced P-selectin exposure with thrombin present and fibrin absent. On collagen/TF, Fab present initially ablated PS exposure, but had no effect when added 30 to 90-s later. The thrombin generated via PS exposure had an important role in driving platelet deposition in the presence of Fab, since inhibition of PS via annexin V binding in the presence of Fab significantly inhibited platelet deposition. We conclude GPVI signaling in the first platelet layer on collagen dictates thrombin and fibrin production, but the role of GPVI at subsequent times after formation of the first monolayer is obscured by thrombin-induced signaling.


Assuntos
Trombina , Tromboplastina , Anexina A5 , Colágeno/metabolismo , Colágeno/farmacologia , Fibrina/metabolismo , Humanos , Microfluídica , Selectina-P/metabolismo , Fosfatidilserinas , Glicoproteínas da Membrana de Plaquetas , Receptores de Colágeno/metabolismo , Trombina/metabolismo , Tromboplastina/metabolismo
17.
Biophys J ; 121(17): 3271-3285, 2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-35927957

RESUMO

Thrombosis, resulting in occlusive blood clots, blocks blood flow to downstream organs and causes life-threatening conditions such as heart attacks and strokes. The administration of tissue plasminogen activator (t-PA), which drives the enzymatic degradation (fibrinolysis) of these blood clots, is a treatment for thrombotic conditions, but the use of these therapeutics is often limited due to the time-dependent nature of treatment and their limited success. We have shown that clot contraction, which is altered in prothrombotic conditions, influences the efficacy of fibrinolysis. Clot contraction results in the volume shrinkage of blood clots, with the redistribution and densification of fibrin and platelets on the exterior of the clot and red blood cells in the interior. Understanding how these key structural changes influence fibrinolysis can lead to improved diagnostics and patient care. We used a combination of mathematical modeling and experimental methodologies to characterize the process of exogenous delivery of t-PA (external fibrinolysis). A three-dimensional (3D) stochastic, multiscale model of external fibrinolysis was used to determine how the structural changes that occur during the process of clot contraction influence the mechanism(s) of fibrinolysis. Experiments were performed based on modeling predictions using pooled human plasma and the external delivery of t-PA to initiate lysis. Analysis of fibrinolysis simulations and experiments indicate that fibrin densification makes the most significant contribution to the rate of fibrinolysis compared with the distribution of components and degree of compaction (p < 0.0001). This result suggests the possibility of a certain fibrin density threshold above which t-PA effective diffusion is limited. From a clinical perspective, this information can be used to improve on current therapeutics by optimizing timing and delivery of lysis agents.


Assuntos
Trombose , Ativador de Plasminogênio Tecidual , Plaquetas/fisiologia , Fibrina/metabolismo , Fibrinólise/fisiologia , Humanos , Ativador de Plasminogênio Tecidual/metabolismo , Ativador de Plasminogênio Tecidual/farmacologia
18.
Shock ; 58(1): 38-44, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35984759

RESUMO

ABSTRACTINTRODUCTION: Although a number of studies have demonstrated increased release of extracellular vesicles (EVs) and changes in their origin differentials after trauma, the biologic significance of EVs is not well understood. We hypothesized that EVs released after trauma/hemorrhagic shock (HS) contribute to endotheliopathy and coagulopathy. To test this hypothesis, adoptive transfer experiments were performed to determine whether EVs derived from severely injured patients in shock were sufficient to induce endothelial dysfunction and coagulopathy. Methods: Total EVs were enriched from plasma of severely injured trauma/HS patients or minimally injured patients by ultracentrifugation and characterized for size and numbers. Under isoflurane anesthesia, noninjured naive C57BL/6J mice were administered EVs at varying concentrations and compared with mice receiving equal volume vehicle (phosphate-buffered saline (PBS)) or to mice receiving EVs from minimally injured patients. Thirty minutes after injection, mice were sacrificed, and blood was collected for thrombin generation (thrombin-antithrombin, thrombin-antithrombin complex [TAT] assay) and syndecan-1 by enzyme-linked immunoabsorbent assay (ELISA). Lungs were harvested for examination of histopathologic injury and costained with von Willebrand factor and fibrin to identify intravascular coagulation. Bronchial alveolar lavage fluid was aspirated from lungs for protein measurement as an indicator of the endothelial permeability. Data are presented as mean ± SD, P < 0.05 was considered significant, and t test was used. Results: An initial proof-of-concept experiment was performed in naive mice receiving EVs purified from severely injured trauma/HS patients (Injury Severity Score [ISS], 34 ± 7) at different concentrations (5 × 106 to 3.1 × 109/100 µL/mouse) and compared with PBS (control) mice. Neither TAT nor syndecan-1 levels were significantly different between groups at 30 minutes after EV infusion. However, lung vascular permeability and histopathologic injury were significantly higher in the EV group, and lung tissues demonstrated intravascular fibrin deposition. Based on these data, EVs from severely injured trauma/HS patients (ISS, 32 ± 6) or EVs from minimally injured patients (ISS, 8 ± 3) were administered to naive mice at higher concentrations (1 × 109 to 1 × 1010 EV/100 µL/mouse). Compared with mice receiving EVs from minimally injured patients, plasma TAT and syndecan-1 levels were significantly higher in the trauma/HS EV group. Similarly, bronchial alveolar lavage protein and lung histopathologic injury were higher in the trauma/HS EV group, and lung tissues demonstrated enhanced intravascular fibrin deposition. Conclusion: These data demonstrate that trauma/HS results in the systemic release of EVs, which are capable of inducing endotheliopathy as demonstrated by elevated syndecan-1 and increased permeability and coagulopathy as demonstrated by increased TAT and intravascular fibrin deposition. Targeting trauma-induced EVs may represent a novel therapeutic strategy.


Assuntos
Transtornos da Coagulação Sanguínea , Vesículas Extracelulares , Choque Hemorrágico , Animais , Transtornos da Coagulação Sanguínea/etiologia , Vesículas Extracelulares/metabolismo , Fibrina , Lesão Pulmonar/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Choque Hemorrágico/metabolismo , Sindecana-1 , Trombina
19.
Shock ; 58(1): 1-13, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35984758

RESUMO

ABSTRACT: Platelets are subcellular anucleate components of blood primarily responsible for initiating and maintaining hemostasis. After injury to a blood vessel, platelets can be activated via several pathways, resulting in changed shape, adherence to the injury site, aggregation to form a plug, degranulation to initiate activation in other nearby platelets, and acceleration of thrombin formation to convert fibrinogen to fibrin before contracting to strengthen the clot. Platelet function assays use agonists to induce and measure one or more of these processes to identify alterations in platelet function that increase the likelihood of bleeding or thrombotic events. In severe trauma, these assays have revealed that platelet dysfunction is strongly associated with poor clinical outcomes. However, to date, the mechanism(s) causing clinically significant platelet dysfunction remain poorly understood. We review the pros, cons, and evidence for use of many of the popular assays in trauma, discuss limitations of their use in this patient population, and present approaches that can be taken to develop improved functional assays capable of elucidating mechanisms of trauma-induced platelet dysfunction. Platelet dysfunction in trauma has been associated with need for transfusions and mortality; however, most of the current platelet function assays were not designed for evaluating trauma patients, and there are limited data regarding their use in this population. New or improved functional assays will help define the mechanisms by which platelet dysfunction occurs, as well as help optimize future treatment.


Assuntos
Plaquetas , Hemostasia , Trombose , Ferimentos e Lesões , Plaquetas/metabolismo , Fibrina/metabolismo , Hemostasia/fisiologia , Humanos , Agregação Plaquetária , Testes de Função Plaquetária/métodos , Ferimentos e Lesões/metabolismo
20.
Cardiovasc Diabetol ; 21(1): 148, 2022 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-35933347

RESUMO

BACKGROUND: Fibrin(ogen) amyloid microclots and platelet hyperactivation previously reported as a novel finding in South African patients with the coronavirus 2019 disease (COVID-19) and Long COVID/Post-Acute Sequelae of COVID-19 (PASC), might form a suitable set of foci for the clinical treatment of the symptoms of Long COVID/PASC. A Long COVID/PASC Registry was subsequently established as an online platform where patients can report Long COVID/PASC symptoms and previous comorbidities. METHODS: In this study, we report on the comorbidities and persistent symptoms, using data obtained from 845 South African Long COVID/PASC patients. By using a previously published scoring system for fibrin amyloid microclots and platelet pathology, we also analysed blood samples from 80 patients, and report the presence of significant fibrin amyloid microclots and platelet pathology in all cases. RESULTS: Hypertension, high cholesterol levels (dyslipidaemia), cardiovascular disease and type 2 diabetes mellitus (T2DM) were found to be the most important comorbidities. The gender balance (70% female) and the most commonly reported Long COVID/PASC symptoms (fatigue, brain fog, loss of concentration and forgetfulness, shortness of breath, as well as joint and muscle pains) were comparable to those reported elsewhere. These findings confirmed that our sample was not atypical. Microclot and platelet pathologies were associated with Long COVID/PASC symptoms that persisted after the recovery from acute COVID-19. CONCLUSIONS: Fibrin amyloid microclots that block capillaries and inhibit the transport of O2 to tissues, accompanied by platelet hyperactivation, provide a ready explanation for the symptoms of Long COVID/PASC. Removal and reversal of these underlying endotheliopathies provide an important treatment option that urgently warrants controlled clinical studies to determine efficacy in patients with a diversity of comorbidities impacting on SARS-CoV-2 infection and COVID-19 severity. We suggest that our platelet and clotting grading system provides a simple and cost-effective diagnostic method for early detection of Long COVID/PASC as a major determinant of effective treatment, including those focusing on reducing clot burden and platelet hyperactivation.


Assuntos
COVID-19 , Diabetes Mellitus Tipo 2 , Amiloide , COVID-19/complicações , COVID-19/epidemiologia , Feminino , Fibrina , Humanos , Masculino , Prevalência , SARS-CoV-2
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...