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1.
Clin Hemorheol Microcirc ; 81(3): 221-232, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35253736

RESUMO

BACKGROUND: Increased risk of thromboembolic events is associated with prostate cancer, specifically linked to activation of tissue factor. Vitamin D has potential anticoagulant effects by the downregulation of tissue factor expression. OBJECTIVES: To evaluate the effects on clot formation, the morphological and viscoelastic profiles of prostate cancer patients, before and after ex vivo supplementation of Vitamin D was studied. METHODS: Participants were recruited into a metastatic, non-metastatic and reference group. Whole blood samples were treated ex vivo with a dose of 0.5µg/kg Calcitriol. Clot kinetics were assessed using Thromboelastography®. Morphology of the blood components were studied using scanning electron microscopy (SEM). RESULTS: Results from the Thromboelastography® and SEM indicated no major differences between the non-metastatic group before and after treatment compared to the reference group. The Thromboelastography® showed that the metastatic group had an increased viscoelastic profile relating to a hypercoagulable state. Visible changes with regards to platelet activation and fibrin morphology were demonstrated with SEM analysis of the metastatic group. The viscoelastic and morphological properties for the non-metastatic group after treatment improved to be comparable to the reference group. CONCLUSION: Vitamin D supplementation may lead to a more favorable viscoelastic profile, with less dangerous clots forming.


Assuntos
Neoplasias da Próstata , Trombose , Suplementos Nutricionais , Fibrina/metabolismo , Humanos , Masculino , Neoplasias da Próstata/tratamento farmacológico , Tromboelastografia , Tromboplastina , Trombose/tratamento farmacológico , Vitamina D/uso terapêutico
2.
Microsc Microanal ; 27(2): 425-436, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33526165

RESUMO

Breast cancer (BC) is one of the most prevalent forms of cancer in women worldwide. Clinical research indicates that BC patients are at an increased risk for thrombotic events, drastically decreasing their quality-of-life and treatment outcomes. There is ample evidence of this in the literature, but it is mainly focused on metastatic BC. Therefore, coagulopathies of nonmetastatic BC are understudied and require in-depth investigation. In this study, clot kinetics and ultrastructure were used to investigate treatment-naïve, nonmetastatic BC patients using scanning electron microscopy, Thromboelastography®, and confocal laser scanning microscopy. It was demonstrated that nonmetastatic BC patients exhibit minimal ultrastructural alterations of the clot components and no changes in the clot kinetics. However, BC patients presented changes to fibrinogen protein structure, compared to matched controls, using an amyloid-selective stain. Together, these findings suggest that coagulation dysfunction(s) in BC patients with early disease manifest at the microlevel, rather than the macrolevel. This study presents novel insights to a method that are more sensitive to coagulation changes in this specific patient group, emphasizing that the coagulation system may react in different forms to the disease, depending on the progression of the disease itself.


Assuntos
Neoplasias da Mama , Trombose , Coagulação Sanguínea , Testes de Coagulação Sanguínea , Feminino , Fibrinogênio/análise , Humanos
3.
OMICS ; 24(7): 404-414, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32471328

RESUMO

The association between hypercoagulability and use of drospirenone (DRSP) and ethinylestradiol (EE) containing combined oral contraceptives (COCs) is an important clinical concern. We have previously reported that the two formulations of DRSP combined with EE (namely, DRSP/20EE and DRSP/30EE) bring about a prothrombotic state in hemostatic traits of female users. We report here the serum metabolomic changes in the same study cohort in relation to the attendant prothrombotic state induced by COC use, thus offering new insights on the underlying biochemical mechanisms contributing to the altered coagulatory profile with COC use. A total of 78 healthy women participated in this study and were grouped as follows: control group not using oral contraceptives (n = 25), DRSP/20EE group (n = 27), and DRSP/30EE group (n = 26). Untargeted metabolomics revealed changes in amino acid concentrations, particularly a decrease in glycine and an increase in both cysteine and lanthionine in the serum, accompanied by variations in oxidative stress markers in the COC users compared with the controls. Of importance, this study is the first to link specific amino acid variations, serum metabolites, and the oxidative metabolic profile with DRSP/EE use. These molecular changes could be linked to specific biophysical coagulatory alterations observed in the same individuals. These new findings lend evidence on the metabolomic substrates of the prothrombotic state associated with COC use in women and informs future personalized/precision medicine research. Moreover, we underscore the importance of an interdisciplinary approach to evaluate venous thrombotic risk associated with COC use.


Assuntos
Androstenos/efeitos adversos , Biomarcadores/sangue , Coagulação Sanguínea/efeitos dos fármacos , Anticoncepcionais Orais Combinados/efeitos adversos , Etinilestradiol/efeitos adversos , Metaboloma , Adolescente , Adulto , Androstenos/administração & dosagem , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Plaquetas/ultraestrutura , Anticoncepcionais Orais Combinados/administração & dosagem , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Eritrócitos/ultraestrutura , Etinilestradiol/administração & dosagem , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Metabolômica/métodos , Ativação Plaquetária/efeitos dos fármacos , Agregação Plaquetária/efeitos dos fármacos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Trombose/sangue , Trombose/diagnóstico , Trombose/etiologia , Adulto Jovem
4.
Cytokine ; 110: 237-242, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29396046

RESUMO

Circulating cytokines, and particularly the interleukin (IL)-family are known to play an important role in inflammation. These molecules circulate in the blood and therefore have a direct effect on the plasma molecules and the formed elements like the erythrocytes and platelets. Aberrant coagulation (hypercoagulation or blood clots that form too easily) and clot lyses (hypofibrinolysis, where clots do not dissolve properly, with an abnormally low rate of clot lysis time), are usually the hallmarks of many inflammatory conditions. However, the mechanism by which cross-linking augments clot stiffness remains undetermined. IL-1ß; IL-6 and IL-8 has been found to be involved in most chronic and acute inflammatory diseases. In the present study, we investigate clot structure of healthy blood, with the addition of these 3 interleukins, to determine the individual effects at concentrations that mimic low-grade, chronic inflammation. Previous studies showed that clot rheological behavior is regulated by at least the following three factors, fibrinogen concentration, fibrin network architecture and FXIIIa-induced ligation. We investigated clot formation and lysis using thromboelastography (TEG), before and after exposure, and created clots by adding thrombin to whole blood. This allowed us to look at extensive fibrin fiber formation and their interactions with particularly the erythrocytes, using scanning electron microscopy (SEM). Our results showed that IL-1ß; IL-6 and IL-8 causes hypercoagulation and results in a disheveled fibrin clot, with trapped RBCs. IL-8 showed eryptosis (a type of apoptosis in erythrocytes). Our lysis results showed that both clot lysis time and maximum rate of lysis are decreased, with the addition of the interleukins. This is a novel finding and the observations reported in this paper, therefore points to the importance of looking at the effects of individual circulating inflammagens, to better understand the role that each play in the expression of disease. These methods can be used for an individualized patient-orientated approach in healthcare to track blood viscosity in conditions with acute and chronic inflammation.


Assuntos
Coagulação Sanguínea/fisiologia , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Interleucina-8/metabolismo , Testes de Coagulação Sanguínea/métodos , Plaquetas/metabolismo , Eritrócitos/metabolismo , Fibrina/metabolismo , Tempo de Lise do Coágulo de Fibrina/métodos , Fibrinogênio/metabolismo , Humanos , Inflamação/metabolismo , Trombina/metabolismo
5.
Sci Rep ; 8(1): 1812, 2018 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-29379088

RESUMO

Tissue necrosis factor-α (TNF-α) and complement component 3 (C3) are two well-known pro-inflammatory molecules. When TNF-α is upregulated, it contributes to changes in coagulation and causes C3 induction. They both interact with receptors on platelets and erythrocytes (RBCs). Here, we look at the individual effects of C3 and TNF-α, by adding low levels of the molecules to whole blood and platelet poor plasma. We used thromboelastography, wide-field microscopy and scanning electron microscopy to study blood clot formation, as well as structural changes to RBCs and platelets. Clot formation was significantly different from the naïve sample for both the molecules. Furthermore, TNF-α exposure to whole blood resulted in platelet clumping and activation and we noted spontaneous plasma protein dense matted deposits. C3 exposure did not cause platelet aggregation, and only slight pseudopodia formation was noted. Therefore, although C3 presence has an important function to cause TNF-α release, it does not necessarily by itself cause platelet activation or RBC damage at these low concentrations. We conclude by suggesting that our laboratory results can be translated into clinical practice by incorporating C3 and TNF-α measurements into broad spectrum analysis assays, like multiplex technology, as a step closer to a patient-orientated, precision medicine approach.


Assuntos
Coagulação Sanguínea/fisiologia , Plaquetas/metabolismo , Complemento C3/metabolismo , Inflamação/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Adulto , Testes de Coagulação Sanguínea/métodos , Plaquetas/fisiologia , Ativação do Complemento/fisiologia , Eritrócitos/metabolismo , Eritrócitos/fisiologia , Feminino , Humanos , Masculino , Ativação Plaquetária/fisiologia , Agregação Plaquetária/fisiologia , Tromboelastografia/métodos , Adulto Jovem
6.
Br J Haematol ; 180(1): 110-117, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29143311

RESUMO

Inflammation, with its associated inflammatory molecules, is integral to most chronic diseases, including the various cardiovascular diseases. Interleukin 12 (IL12) is one of the inflammatory cytokines that is upregulated during inflammation; however, we know very little about its exact effect on red blood cells (RBCs), platelets and fibrin(ogen). IL12 is an important pleiotropic cytokine in early inflammatory responses and has potent immunomodulatory, antitumour and anti-infection activity. Here we investigate how low levels of circulating IL12, comparable to levels found during chronic inflammation, affect coagulation parameters, platelets and RBCs. We used thromboelastography, scanning electron microscopy, refractometery and wide-field microscopy. Our results show that IL12 caused hypercoagulation, platelet activation and spreading, as well as RBC agglutination. This phenomenon has far-reaching implications for treatment of the plethora of conditions where IL12 is upregulated, since it suggests aberrant haemorheology as agglutination affects blood flow. This information might be used in future to target the lowering of IL12 in inflammatory conditions, as well as address RBC agglutination.


Assuntos
Plaquetas/efeitos dos fármacos , Coagulantes/farmacologia , Eritrócitos/efeitos dos fármacos , Fibrinogênio/metabolismo , Interleucina-12/sangue , Interleucina-12/farmacologia , Adolescente , Adulto , Coagulação Sanguínea/efeitos dos fármacos , Plaquetas/ultraestrutura , Técnicas de Imagem por Elasticidade/métodos , Eritrócitos/ultraestrutura , Feminino , Hemorreologia , Humanos , Inflamação/sangue , Inflamação/etiologia , Inflamação/metabolismo , Masculino , Microscopia/métodos , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Refratometria , Adulto Jovem
7.
Cell Physiol Biochem ; 43(3): 1288-1300, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28992628

RESUMO

BACKGROUND/AIMS: Heavy metal pollution is increasing in the environment, contaminating water, food and air supplies. This can be linked to many anthropogenic activities. Heavy metals are absorbed through the skin, inhalation and/or orally. Irrespective of the manner of heavy metal entry in the body, the blood circulatory system is potentially the first to be affected following exposure and adverse effects on blood coagulation can lead to associated thrombotic disease. Although the plasma levels and the effects of cadmium (Cd) and chromium (Cr) on erythrocytes and lymphocytes have been described, the environmental exposure to heavy metals are not limited to a single metal and often involves metal mixtures, with each metal having different rates of absorption, different cellular, tissue, and organ targets. Therefore the aim of this study is to investigate the effects of the heavy metals Cd and Cr alone and whether Cr synergistically increases the effect of Cd on physiological important processes such as blood coagulation. METHODS: Human blood was exposed to the heavy metals ex vivo, and thereafter morphological analysis was performed with scanning electron- and confocal laser scanning microscopy (CLSM) in conjunction with thromboelastography®. RESULTS: The erythrocytes, platelets and fibrin networks presented with ultrastructural changes, including varied erythrocytes morphologies, activated platelets and significantly thicker fibrin fibres in the metal-exposed groups. CLSM analysis revealed the presence of phosphatidylserine on the outer surface of the membranes of the spherocytic erythrocytes exposed to Cd and Cr alone and in combination. The viscoelastic analysis revealed only a trend that indicates that clots that will form after heavy metal exposure, will likely be fragile and unstable especially for Cd and Cr in combination. CONCLUSION: This study identified the blood as an important target system of Cd and Cr toxicity.


Assuntos
Células Sanguíneas/efeitos dos fármacos , Cádmio/toxicidade , Cromo/toxicidade , Plasma/efeitos dos fármacos , Células Sanguíneas/fisiologia , Células Sanguíneas/ultraestrutura , Plaquetas/efeitos dos fármacos , Plaquetas/fisiologia , Plaquetas/ultraestrutura , Elasticidade/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Eritrócitos/fisiologia , Eritrócitos/ultraestrutura , Fibrina/efeitos dos fármacos , Fibrina/fisiologia , Fibrina/ultraestrutura , Humanos , Microscopia Confocal , Plasma/fisiologia , Tromboelastografia , Viscosidade/efeitos dos fármacos
8.
Sci Rep ; 6: 32188, 2016 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-27561337

RESUMO

Complex interactions exist between cytokines, and the interleukin family plays a fundamental role in inflammation. Particularly circulating IL-1ß, IL-6 and IL-8 are unregulated in systemic and chronic inflammatory conditions. Hypercoagulability is an important hallmark of inflammation, and these cytokines are critically involved in abnormal clot formation, erythrocyte pathology and platelet hyper-activation, and these three cytokines have known receptors on platelets. Although these cytokines are always unregulated in inflammation, we do not know how the individual cytokines act upon the structure of erythrocytes and platelets, and which of the viscoelastic clot parameters are changed. Here we study the effects of IL-1ß, IL-6 and IL-8 at low physiological levels, representative of chronic inflammation, by using scanning electron microscopy and thromboelastography. All three interleukins caused the viscoelastic properties to display an increased hypercoagulability of whole blood and pathology of both erythrocytes and platelets. The most pronounced changes were noted where all three cytokines caused platelet hyper-activation and spreading. Erythrocyte structure was notably affected in the presence of IL-8, where the morphological changes resembled that typically seen in eryptosis (programmed cell death). We suggest that erythrocytes and platelets are particularly sensitive to cytokine presence, and that they are excellent health indicators.


Assuntos
Coagulação Sanguínea , Interleucina-1beta/farmacologia , Interleucina-6/farmacologia , Interleucina-8/farmacologia , Viscosidade Sanguínea , Elasticidade , Feminino , Humanos , Masculino
9.
J Alzheimers Dis ; 53(4): 1237-56, 2016 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-27340854

RESUMO

The progression of Alzheimer's disease (AD) is accompanied by a great many observable changes, both molecular and physiological. These include oxidative stress, neuroinflammation, and (more proximal to cognitive decline) the death of neuronal and other cells. A systems biology approach seeks to organize these observed variables into pathways that discriminate those that are highly involved (i.e., causative) from those that are more usefully recognized as bystander effects. We review the evidence that iron dysregulation is one of the central causative pathway elements here, as this can cause each of the above effects. In addition, we review the evidence that dormant, non-growing bacteria are a crucial feature of AD, that their growth in vivo is normally limited by a lack of free iron, and that it is this iron dysregulation that is an important factor in their resuscitation. Indeed, bacterial cells can be observed by ultrastructural microscopy in the blood of AD patients. A consequence of this is that the growing cells can shed highly inflammatory components such as lipopolysaccharides (LPS). These too are known to be able to induce (apoptotic and pyroptotic) neuronal cell death. There is also evidence that these systems interact with elements of vitamin D metabolism. This integrative systems approach has strong predictive power, indicating (as has indeed been shown) that both natural and pharmaceutical iron chelators might have useful protective roles in arresting cognitive decline, and that a further assessment of the role of microbes in AD development is more than highly warranted.


Assuntos
Doença de Alzheimer/metabolismo , Doença de Alzheimer/microbiologia , Fenômenos Fisiológicos Bacterianos , Ferro/metabolismo , Doença de Alzheimer/patologia , Animais , Humanos , Biologia de Sistemas
10.
Ultrastruct Pathol ; 40(1): 57-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26691215

RESUMO

Transient ischemic attack (TIA) is an important predictor of future ischemic events, including stroke. Due to the typically brief period of neurologic dysfunction, patients often overlook the importance of reporting a TIA. We have recently shown that platelet activation plays an important role in TIA pathology. In a similar vein, smoking is associated with a hypercoagulable state and is also one of the important risk factors for stroke. Here we present an interesting case where a 61-year-old male, with hypercholesterolemia, and a previous heart valve replacement, developed a TIA 5 months after he started smoking. Subsequent to the event, Warfarin dosage was monitored monthly using the international normalized ratio (INR). We compared erythrocyte and platelet morphology of healthy individuals, that of smokers, individuals who had a diagnosed TIA (without smoking), and the patient. The erythrocytes from the case study are ultrastructurally similar to that of a smoker, while his platelets are similar to that of smokers and TIA patients who do not smoke. We conclude that smoking exacerbated the chronic inflammation induced by hypercholesterolemia, causing changes in his erythrocyte morphology and platelet activation, and suggest that ultrastructure here explains the clinical manifestations of the thrombotic state of this patient.


Assuntos
Plaquetas/ultraestrutura , Eritrócitos/ultraestrutura , Ataque Isquêmico Transitório/patologia , Fumar , Acidente Vascular Cerebral/patologia , Humanos , Ataque Isquêmico Transitório/diagnóstico , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Acidente Vascular Cerebral/diagnóstico
11.
Curr Neurovasc Res ; 12(1): 31-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25557378

RESUMO

Alzheimer's disease (AD) is a significant source of morbidity and mortality for millions of people worldwide, and multiple potential etiologies have been postulated to contribute to AD. Among these, spontaneous cerebral emboli and increased cerebral and circulating heme oxygenase (Hmox) activity in AD patients are of particular interest, as two of the products of Hmox activity, carbon monoxide (CO) and iron enhance plasmatic coagulation and modify the ultrastructure of thrombi. We hypothesized that patients afflicted with AD would have coagulation kinetics modulated by CO and iron. Using viscoelastic assessments of coagulation, it was determined with a small cohort (n=11) of AD patients that all had enhancement of coagulation by CO, iron, or both. In a complementary fashion, it was determined that a separate cohort (n=12) of AD patients had thrombi with ultrastructural features consistent with iron and CO exposure as assessed with scanning electron microscopy. Further, when stratified by normal or abnormally increased serum ferritin concentrations (which can be increased by Hmox), the AD patients with abnormal ferritin concentrations had significantly thinner fibrin fiber diameters, not unlike that noted when normal plasma is mixed with iron or CO. In sum, AD patients were noted to have plasmatic coagulation kinetic and thrombus ultrastructural changes consistent with exposure to CO and iron. Future investigation of CO and iron in the pathogenesis of Alzheimer's disease is warranted.


Assuntos
Doença de Alzheimer/sangue , Coagulação Sanguínea/efeitos dos fármacos , Monóxido de Carbono/farmacologia , Ferro/farmacologia , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Ferritinas/metabolismo , Fibrinogênio/metabolismo , Humanos , Masculino , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Plasma/diagnóstico por imagem , Plasma/metabolismo , Cintilografia , Trombina/metabolismo
13.
PLoS One ; 9(1): e85271, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24416376

RESUMO

It is well-known that individuals with increased iron levels are more prone to thrombotic diseases, mainly due to the presence of unliganded iron, and thereby the increased production of hydroxyl radicals. It is also known that erythrocytes (RBCs) may play an important role during thrombotic events. Therefore the purpose of the current study was to assess whether RBCs had an altered morphology in individuals with hereditary hemochromatosis (HH), as well as some who displayed hyperferritinemia (HF). Using scanning electron microscopy, we also assessed means by which the RBC and fibrin morphology might be normalized. An important objective was to test the hypothesis that the altered RBC morphology was due to the presence of excess unliganded iron by removing it through chelation. Very striking differences were observed, in that the erythrocytes from HH and HF individuals were distorted and had a much greater axial ratio compared to that accompanying the discoid appearance seen in the normal samples. The response to thrombin, and the appearance of a platelet-rich plasma smear, were also markedly different. These differences could largely be reversed by the iron chelator desferal and to some degree by the iron chelator clioquinol, or by the free radical trapping agents salicylate or selenite (that may themselves also be iron chelators). These findings are consistent with the view that the aberrant morphology of the HH and HF erythrocytes is caused, at least in part, by unliganded ('free') iron, whether derived directly via raised ferritin levels or otherwise, and that lowering it or affecting the consequences of its action may be of therapeutic benefit. The findings also bear on the question of the extent to which accepting blood donations from HH individuals may be desirable or otherwise.


Assuntos
Eritrócitos/patologia , Ferritinas/sangue , Fibrina/ultraestrutura , Hemocromatose/tratamento farmacológico , Quelantes de Ferro/uso terapêutico , Ferro/metabolismo , Adolescente , Adulto , Criança , Clioquinol/uso terapêutico , Desferroxamina/uso terapêutico , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Feminino , Ferritinas/antagonistas & inibidores , Fibrina/metabolismo , Hemocromatose/metabolismo , Hemocromatose/patologia , Humanos , Radical Hidroxila/antagonistas & inibidores , Radical Hidroxila/metabolismo , Masculino , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade , Plasma Rico em Plaquetas/química , Ácido Salicílico/uso terapêutico , Ácido Selenioso/uso terapêutico , Trombina/farmacologia , Regulação para Cima
14.
Toxicol Mech Methods ; 23(5): 352-9, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23278212

RESUMO

AIMS: Inflammatory diseases associated with iron overload are characterized by a changed coagulation profile, where there is a persistent presence of fibrin-like material of dense-matted deposits (DMDs). It is believed that one source of such material is a result of the activation of blood coagulation without the generation of thrombin, causing clots to become resistant to fibrinolytic dissolution. The aim of the current manuscript therefore is to apply a novel scanning electron microscopy method for assessing the role of functional chelation in the prevention or reversal of iron-induced fibrin formation. METHODS AND RESULTS: Purified fibrinogen and platelet-rich plasma were exposed to chelating agents followed by iron, to determine the chelating effects. We show that there is another, pathological pathway of fibrin formation initiated by free iron (initially as Fe (III)), leading to the formation of highly reactive oxygen species such as the hydroxyl radical that can oxidize and insolubilize proteins, a process that might be inhibited by iron-chelating compounds. The final product of such a pathway is a fibrin-like material, termed DMDs that are remarkably resistant to proteolytic degradation. CONCLUSIONS: Scanning electron microscopy shows that iron-chelating agents are effective inhibitors of DMD formation. The most active inhibitors of DMD formation proved to be Desferal, Clioquinol and Curcumin, whereas Epigallocatechin gallate and Deferiprone were less effective. The functional model we describe may point the clinical utility of various substances in iron-mediated degenerative diseases.


Assuntos
Fibrina/metabolismo , Quelantes de Ferro/metabolismo , Ferro/fisiologia , Adulto , Fibrinólise , Humanos , Microscopia Eletrônica de Varredura , Adulto Jovem
15.
Microsc Res Tech ; 76(3): 268-71, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23280783

RESUMO

Fibrinogen is key to the maintenance of hemostasis and is an acute phase protein that is part of the coagulation cascade of proteins. It plays a fundamental role in inflammation, particularly as indicator for a proinflammatory state and is a prominent marker for developing vascular inflammatory diseases. The ultrastructure of fibrin nets can be studied using scanning electron microscopy (SEM) with the addition of thrombin to plasma. In inflammatory conditions such as thromboembolic ischemic stroke and diabetes, the fibrin networks are changed to from dense matted fibrin deposits (DMDs) instead of typical netlike appearance. Similar DMDs can also be induced with the addition of FeCl(2) and FeCl(3). Importantly, the iron-induced DMDs look similar to those from patients with prothrombotic conditions. Excessive or misplaced tissue iron now is recognized to pose a substantial health risk. The current research therefore investigates the establishment of a laboratory fibrinogen model to study that might mimic fibrin fiber generation that is achieved using plasma from healthy and diseased individuals. Furthermore, to determine whether the addition of iron to purified fibrinogen will show DMDs and whether hydrophilic agents can prevent them. We conclude that SEM is a very effective tool for the visualization of circulatory consequences of the interaction of iron-induced hydroxyl radicals with human fibrinogen. Furthermore, this novel fibrinogen model provides a convenient method to study the interactions of the intramolecular and intermolecular hydrophobic forces responsible for the maintenance of the tertiary structure of native fibrin(ogen) and the prevention of iron-induced DMDs formation by hydrophilic agents.


Assuntos
Fibrina/metabolismo , Fibrina/ultraestrutura , Fibrinogênio/metabolismo , Ferro/metabolismo , Humanos , Radical Hidroxila/metabolismo , Microscopia Eletrônica de Varredura
16.
Curr Drug Targets ; 14(1): 13-9, 2013 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-23170793

RESUMO

Blood coagulation under physiological conditions is activated by thrombin, which converts soluble plasma fibrinogen (FBG) into an insoluble clot. The structure of the enzymatically-generated clot is very characteristic being composed of thick fibrin fibers susceptible to the fibrinolytic degradation. However, in chronic degenerative diseases, such as atherosclerosis, diabetes mellitus, cancer, and neurological disorders, fibrin clots are very different forming dense matted deposits (DMD) that are not effectively removed and thus create a condition known as thrombosis. We have recently shown that trivalent iron (ferric ions) generates hydroxyl radicals, which subsequently convert FBG into abnormal fibrin clots in the form of DMDs. A characteristic feature of DMDs is their remarkable and permanent resistance to the enzymatic degradation. Therefore, in order to prevent thrombotic incidences in the degenerative diseases it is essential to inhibit the iron-induced generation of hydroxyl radicals. This can be achieved by the pretreatment with a direct free radical scavenger (e.g. salicylate), and as shown in this paper by the treatment with oxidizing agents such as hydrogen peroxide, methylene blue, and sodium selenite. Although the actual mechanism of this phenomenon is not yet known, it is possible that hydroxyl radicals are neutralized by their conversion to the molecular oxygen and water, thus inhibiting the formation of dense matted fibrin deposits in human blood.


Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Cloretos/farmacologia , Compostos Férricos/farmacologia , Fibrina/química , Fibrinogênio/química , Radical Hidroxila/antagonistas & inibidores , Oxidantes/farmacologia , Adulto , Coagulação Sanguínea/fisiologia , Feminino , Fibrina/ultraestrutura , Fibrinogênio/ultraestrutura , Humanos , Peróxido de Hidrogênio/farmacologia , Azul de Metileno/farmacologia , Microscopia Eletrônica de Varredura , Oxirredução , Selenito de Sódio/farmacologia , Trombose/sangue , Trombose/prevenção & controle , Adulto Jovem
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