scholarly journals Thrombopoietin as Biomarker and Mediator of Cardiovascular Damage in Critical Diseases

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Enrico Lupia ◽  
Alberto Goffi ◽  
Ornella Bosco ◽  
Giuseppe Montrucchio
Keyword(s):  
Platelet Aggregation ◽  
Research Group ◽  
Burn Injury ◽  
Pathogenic Role ◽  
Cigarette Smokers ◽  
Induce Platelet Aggregation ◽  
Cardiovascular Damage ◽  
Proliferation And Differentiation

Thrombopoietin (TPO) is a humoral growth factor originally identified for its ability to stimulate the proliferation and differentiation of megakaryocytes. In addition to its actions on thrombopoiesis, TPO directly modulates the homeostatic potential of mature platelets by influencing their response to several stimuli. In particular, TPO does not induce platelet aggregationper sebut is able to enhance platelet aggregation in response to different agonists (“priming effect”). Our research group was actively involved, in the last years, in characterizing the effects of TPO in several human critical diseases. In particular, we found that TPO enhances platelet activation and monocyte-platelet interaction in patients with unstable angina, chronic cigarette smokers, and patients with burn injury and burn injury complicated with sepsis. Moreover, we showed that TPO negatively modulates myocardial contractility by stimulating its receptor c-Mpl on cardiomyocytes and the subsequent production of NO, and it mediates the cardiodepressant activity exertedin vitroby serum of septic shock patients by cooperating with TNF-αand IL-1β. This paper will summarize the most recent results obtained by our research group on the pathogenic role of elevated TPO levels in these diseases and discuss them together with other recently published important studies on this topic.

Effect of Temperature on ADP-Induced Platelet Aggregation

1973 ◽  
Vol 29 (01) ◽  
pp. 183-189
Author(s):  
C. A Praga ◽  
E. M Pogliani
Keyword(s):  
Platelet Aggregation ◽  
Incubation Period ◽  
Room Temperature ◽  
Important Variable ◽  
Practical Significance ◽  
Effect Of Temperature ◽  
Induce Platelet Aggregation ◽  
Cuvette Holder ◽  
Exact Temperature

SummaryTemperature represents a very important variable in ADP-induced platelet aggregation.When low doses of ADP ( < 1 (μM) are used to induce platelet aggregation, the length of the incubation period of PRP in the cuvette holder of the aggregometer, thermostatted at 37° C, is very critical. Samples of the same PRP previously kept at room temperature, were incubated for increasing periods of time in the cuvette of the aggregometer before adding ADP, and a significant decrease of aggregation, proportional to the length of incubation, was observed. Stirring of the PRP during the incubation period made these changes more evident.To measure the exact temperature of the PRP during incubation in the aggre- gometer, a thermocouple device was used. While the temperature of the cuvette holder was stable at 37° C, the PRP temperature itself increased exponentially, taking about ten minutes from the beginning of the incubation to reach the value of 37° C. The above results have a practical significance in the reproducibility of the platelet aggregation test in vitro and acquire particular value when the effect of inhibitors of ADP induced platelet aggregation is studied.Experiments carried out with three anti-aggregating agents (acetyl salicyclic acid, dipyridamole and metergoline) have shown that the incubation conditions which influence both the effect of the drugs on platelets and the ADP breakdown in plasma must be strictly controlled.

Effect of Dipyridamole on Spontaneous Platelet Aggregation in Whole Blood Decreases with the Time After Venepuncture: Evidence for the Role of ADP

1987 ◽  
Vol 58 (02) ◽  
pp. 744-748 ◽  
Author(s):  
A R Saniabadi ◽  
G D O Lowe ◽  
J C Barbenel ◽  
C D Forbes
Keyword(s):  
Platelet Aggregation ◽  
Correlation Coefficient ◽  
Whole Blood ◽  
Blood Platelet ◽  
Inhibitory Effect ◽  
Time Interval ◽  
Adp Receptor ◽  
Spontaneous Platelet Aggregation

SummarySpontaneous platelet aggregation (SPA) was studied in human whole blood at 3, 5, 10, 20, 30, 40 and 60 minutes after venepuncture. Using a whole blood platelet counter, SPA was quantified by measuring the fall in single platelet count upon rollermixing aliquots of citrated blood at 37° C. The extent of SPA increased with the time after venepuncture, with a correlation coefficient of 0.819. The inhibitory effect of dipyridamole (Dipy) on SPA was studied: (a) 10 μM at each time interval; (b) 0.5-100 μM at 3 and 30 minutes and (c) 15 μM in combination with 100 μM adenosine, 8 μM 2-chloroadenosine (2ClAd, an ADP receptor blocker) and 50 μM aspirin. There was a rapid decrease in the inhibitory effect of Dipy with the time after venepuncture; the correlation coefficient was -0.533. At all the concentrations studied, Dipy was more effective at 3 minutes than at 30 minutes after venepuncture. A combination of Dipy with adenosine, 2ClAd or aspirin was a more effective inhibitor of SPA than either drug alone. However, when 15 μM Dipy and 10 μM Ad were added together, the inhibitory effect of Dipy was not increased significantly, suggesting that Dipy inhibits platelet aggregation independent of Ad. The increase in SPA with the time after venepuncture was abolished when blood was taken directly into the anticoagulant containing 5 μM 2ClAd. It is suggested that ADP released from the red blood cells is responsible for the increased platelet aggregability with the time after venepuncture and makes a serious contribution to the artifacts of in vitro platelet function studies.

scholarly journals Increased Expression of Retinol-Binding Protein 4 in Ovarian Endometrioma and Its Possible Role in the Pathogenesis of Endometriosis

2021 ◽  
Vol 22 (11) ◽  
pp. 5827
Author(s):  
Jae Chul Lee ◽  
Sung Hoon Kim ◽  
Young Sang Oh ◽  
Ju Hee Kim ◽  
Sa Ra Lee ◽  
...  
Keyword(s):  
Retinol Binding Protein ◽  
Endometrial Stromal Cells ◽  
Endometrial Cells ◽  
Retinol Binding Protein 4 ◽  
Ovarian Endometrioma ◽  
Proliferation And Differentiation ◽  
In Vitro Effects ◽  
Ovarian Endometriomas

Although endometriosis is a benign disease characterized by the presence of endometrial tissues outside the uterus, ectopic endometrial cells can exhibit malignant biological behaviors. Retinol-binding protein4 (RBP4) is a novel adipocyte-derived cytokine, which has important roles in regulating insulin sensitivity and energy metabolism. RBP4 is a potent modulator of gene transcription, and acts by directly controlling cell growth, invasiveness, proliferation and differentiation. Here, we evaluated the possible role of RBP4 in the pathogenesis of endometriosis. We compared the levels of RBP4 in the tissues and peritoneal fluid (PF) of women with and without endometriosis and evaluated the in vitro effects of RBP4 on the viability, invasiveness, and proliferation of endometrial stromal cells (ESCs). RBP4 levels were significantly higher in the PF of the women in the endometriosis group than in the controls. RBP4 immunoreactivity was significantly higher in the ovarian endometriomas of women with advanced stage endometriosis than those of controls. In vitro treatment with human recombinant-RBP4 significantly increased the viability, bromodeoxyuridine expression, and invasiveness of ESCs. Transfection with RBP4 siRNA significantly reduced ESC viability and invasiveness. These findings suggest that RBP4 partakes in the pathogenesis of endometriosis by increasing the viability, proliferation and invasion of endometrial cells.

scholarly journals ROLE OF NITRIC OXIDE (NO) IN CAPSAICIN MEDIATED ANTI-PLATELET ACTIVITY IN IN VITRO, IN VIVO, EX-VIVO MODEL OF PLATELET AGGREGATION ASSAY AND ARTERIAL THROMBOSIS IN RAT: POTENTIAL THERAPEUTIC TARGET?

2018 ◽  
Vol 10 (4) ◽  
pp. 44
Author(s):  
Mihir K Patel ◽  
Kiranj K. Chaudagar ◽  
Anita A. Mehta
Keyword(s):  
Platelet Aggregation ◽  
Arterial Thrombosis ◽  
Ex Vivo ◽  
Platelet Activity ◽  
Aggregation Assay ◽  
Thrombosis Model ◽  
Platelet Aggregation Assay

Objective: Although recent advances in the treatment of congestive heart disease, mortality among patients’ remains a questionable remark. Therefore, we evaluated the role of capsaicin on in vitro and ex vivo platelet aggregation induced by Adenosine Di-Phosphate (ADP) as well as in in vivo thrombosis models and role of NO, KATP was also identified in the capsaicin-induced anti-platelet animal model as well as in vivo model of arterial thrombosis.Methods: According to body weight wistar rats were divided into five groups. Group I and Group II was treated with saline and capsaicin (3 mg/kg, i. v), while animals from Group III were treated with N(ω)-nitro-L-arginine methyl ester (L-NAME) (30 mg/kg, i. v) 30 min before administration of capsaicin (3 mg/kg, i. v). Group IV animals were treated with glibenclamide (10 mg/kg,i. v) 30 min before administration of capsaicin (3 mg/kg, i. v). Group V was considered as a positive control and administered clopidogrel (30 mg/kg, p. o). Animals were subjected for in vitro, ex-vivo platelet aggregation assay. ADP (30µM) was utilized as an aggregating agent in these experiments. After these assays; animals of each group were subjected for subaqueous tail bleeding time in a rat model and FeCl3-induced arterial thrombosis model in rats.Results: In ADP-induced in vitro platelet aggregation, a significant reduction in % platelet aggregation was observed at 50µM (64.35±4.641) and 100µM (52.72±4.192) concentration of capsaicin as compared to vehicle control (85.82±3.716). Capsaicin (3 mg/kg, i. v) also showed a significant reduction (49.53±4.075) in ex-vivo ADP-induced platelet aggregation as compared to vehicle control (89.38±2.057). In FeCl3 induced arterial thrombosis model, Capsaicin (3 mg/kg, i. v) exhibited an increase in time to occlusion in this rodent model and presence of the L-NAME and glibenclamide had inhibited the activity of capsaicin.Conclusion: In our study, capsaicin (50 µM, 100µM) exhibited potent anti-platelet activity in ADP-induced platelet aggregation, similarly capsaicin exhibited significant anti-platelet action in the ex-vivo study. Moreover, the presence of L-NAME and glibenclamide inhibited the anti-thrombotic and anti-platelet action of capsaicin. Therefore, it was concluded that NO and KATP may be involved in the anti-thrombotic action of capsaicin.

scholarly journals Study of Staphylococcus aureusPathogenic Genes by Transfer and Expression in the Less Virulent Organism Streptococcus gordonii

2001 ◽  
Vol 69 (2) ◽  
pp. 657-664 ◽  
Author(s):  
P. Stutzmann Meier ◽  
J. M. Entenza ◽  
P. Vaudaux ◽  
P. Francioli ◽  
M. P. Glauser ◽  
...  
Keyword(s):  
Single Gene ◽  
Individual Factors ◽  
Gene Products ◽  
Streptococcus Gordonii ◽  
Pathogenic Role ◽  
Gain Of Function ◽  
Function Strategy

ABSTRACT Because Staphylococcus aureus strains contain multiple virulence factors, studying their pathogenic role by single-gene inactivation generated equivocal results. To circumvent this problem, we have expressed specific S. aureus genes in the less virulent organism Streptococcus gordonii and tested the recombinants for a gain of function both in vitro and in vivo. Clumping factor A (ClfA) and coagulase were investigated. Both gene products were expressed functionally and with similar kinetics during growth by streptococci and staphylococci. ClfA-positive S. gordoniiwas more adherent to platelet-fibrin clots mimicking cardiac vegetations in vitro and more infective in rats with experimental endocarditis (P < 0.05). Moreover, deletingclfA from clfA-positive streptococcal transformants restored both the low in vitro adherence and the low in vivo infectivity of the parent. Coagulase-positive transformants, on the other hand, were neither more adherent nor more infective than the parent. Furthermore, coagulase did not increase the pathogenicity ofclfA-positive streptococci when both clfA andcoa genes were simultaneously expressed in an artificial minioperon in streptococci. These results definitively attribute a role for ClfA, but not coagulase, in S. aureus endovascular infections. This gain-of-function strategy might help solve the role of individual factors in the complex the S. aureus-host relationship.

scholarly journals Haemodynamic flow conditions at the initiation of high-shear platelet aggregation: a combined in vitro and cellular in silico study

2020 ◽  
Vol 11 (1) ◽  
pp. 20190126 ◽  
Author(s):  
B. J. M. van Rooij ◽  
G. Závodszky ◽  
A. G. Hoekstra ◽  
D. N. Ku
Keyword(s):  
Platelet Aggregation ◽  
In Silico ◽  
Platelet Rich Plasma ◽  
High Shear ◽  
Shear Rates ◽  
Flow Simulations ◽  
In Silico Study ◽  
Platelet Aggregates

The influence of the flow environment on platelet aggregation is not fully understood in high-shear thrombosis. The objective of this study is to investigate the role of a high shear rate in initial platelet aggregation. The haemodynamic conditions in a microfluidic device are studied using cell-based blood flow simulations. The results are compared with in vitro platelet aggregation experiments performed with porcine whole blood (WB) and platelet-rich-plasma (PRP). We studied whether the cell-depleted layer in combination with high shear and high platelet flux can account for the distribution of platelet aggregates. High platelet fluxes at the wall were found in silico . In WB, the platelet flux was about twice as high as in PRP. Additionally, initial platelet aggregation and occlusion were observed in vitro in the stenotic region. In PRP, the position of the occlusive thrombus was located more downstream than in WB. Furthermore, the shear rates and stresses in cell-based and continuum simulations were studied. We found that a continuum simulation is a good approximation for PRP. For WB, it cannot predict the correct values near the wall.

Role of glycine-containing oligopeptides in blood cells aggregation stimulated by adrenaline

2017 ◽  
Author(s):  
М. Голубева
Keyword(s):  
Body Weight ◽  
Platelet Aggregation ◽  
Blood Cells ◽  
Regulatory Peptides ◽  
Pituitary Hormones ◽  
New Drugs ◽  
Male Rats ◽  
Current Interest

Введение. Изменение реологических свойств крови характерно для различных заболеваний, многие из которых связаны с нарушением реологии и, прежде всего, с изменением агрегации эритроцитов. Целью исследования было сравнение влияния малых регуляторных пептидов, являющихся фрагментами нейрогормонов, на агрегацию эритроцитов и тромбоцитов под действием адреналина в экспериментах in vitro. Материалы и методы. Эксперименты проводили на белых беспородных крысах-самцах, массой тела 180-200 г. Использовали пептиды, представляющие собой С-концевые фрагменты вазопрессина (Pro-Arg-Gly-NH2) и окситоцина (Pro-Leu-Gly-NH2). Результаты. Показано, что малые регуляторные пептиды, являющиеся продуктами протеолиза нейропептидов, оказывают существенное влияние на агрегатное состояние клеток крови. При сравнении влияния пептидов на агрегацию клеток крови, стимулированную адреналином, установлено, что фрагмент вазопрессина Pro-Arg-Gly-NH2 вызывал достоверное усиление агрегации как эритроцитов, так и тромбоцитов; тогда как фрагмент окситоцина Pro-Leu-Gly-NH2 ингибировал только агрегацию эритроцитов, не изменяя агрегации тромбоцитов. Заключение. Изучение путей поэтапного протеолиза пептидов может привести к разработке новых препаратов для направленной коррекции различных нарушений в организме, поэтому изучение эффектов С-концевых фрагментов гипофизарных гормонов на гемостаз является актуальным. Introduction. The changing of blood rheological properties is typical for various diseases; many of them are associated with rheology disorder and primarily with change of erythrocytes aggregation. The aim was to compare the effect of small regulatory peptides (fragments of neurohormones) on the aggregation of erythrocytes and platelets under adrenaline action in experiments in vitro. Materials and methods. Experiments were conducted on white outbred male rats, body weight 180-200 g. We used 2 peptides – C-terminal fragments of vasopressin (Pro-Arg-Gly-NH2) and oxytocin (Pro-Leu-Gly-NH2). Results. It was shown that small regulatory peptides (they are products of neuropeptides proteolysis) had a significant effect on blood cells aggregation. We compared the peptides effect on blood cells aggregation stimulated by adrenaline. It was found that vasopressin fragment Pro-Arg-Gly-NH2 significantly increased both erythrocytes and platelets aggregation, while oxytocin fragment Pro-Leu-Gly-NH2 inhibited only erythrocytes aggregation without changing of platelet aggregation. Conclusion. Investigation of phased peptides proteolysis may result in the development of new drugs for targeted correction of various disturbances. So it is of current interest to study the effects of C-terminal fragments of pituitary hormones on hemostasis.

Synergism Between Platelet Aggregating Agents: Possible Trigger Mechanisms During Hemostatic Plug And/Or Thrombus Formation

1981 ◽  
Author(s):  
S C Wong ◽  
G A Rock
Keyword(s):  
Platelet Aggregation ◽  
Serine Protease ◽  
Protease Inhibitors ◽  
Synergistic Effects ◽  
Thrombus Formation ◽  
Thrombotic Event ◽  
Atp Release ◽  
Serine Protease Inhibitors ◽  
Induce Platelet Aggregation

number of in-vitro studies have shown that various pair-combinations of aggregating agents such as ADP, epinephrine, collagen, thrombin, arachidonate and ionophore A 23187 can produce synergistic responses to induce platelet aggregation and release reactions. We have also produced synergistic effects by combining much lower doses of 3 or more aggregating agents and found markedly enhanced responses. It appears that the potential for synergistic effects is based both on the combination of the various agents and on the amount of each agent used for stimulation. Epinephrine is the most potent agent among them, although fibrinogen and Ca++ play a very important role. Indomethacin, ASA, PGE 1, and synthetic serine protease inhibitors (carboxylate and sulphonate analog) completely inhibit the platelet aggregation and release response. Of particular interest is the fact that addition of as little as 0.04% of the usual aggregating dose of epinephrine in the presence of 4% of collagen, 2% of thrombin and 10% of the normal plasma level of fibrinogen will initiate a marked response both of platelet aggregation and ATP release. This suggests a possible mechanism whereby acute insults such as stress or exercise, with release of epinephrine, can precipitate a thrombotic event in a patient who has normal or near-normal circulating levels of fibrinogen but who also has exposure of a very limited amount of the vascular endothelium (thereby exposing collagen). Since the effects of the acute insults of epinephrine secretion can be blocked by the presence of indomethacin, ASA, PGE 1 and specific serine protease inhibitors, prostaglandin synthesis must play a major role in this reaction.

IMPORTANCE OF LARGE VON WILLEBRAND FACTOR (vWF) MULTIMERS IN vWF INTERACTION WITH PLATELET GLYCOPROTEIN IIb/IIIa

1987 ◽  
Author(s):  
M Yamamoto ◽  
Y Ando ◽  
K Watanabe ◽  
H Iri ◽  
Y Araki ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
Platelet Glycoprotein ◽  
Induce Platelet Aggregation ◽  
Maximum Extent ◽  
Physiological Relevance ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor

Recently it has been reported that, in addition to binding to glycoprotein (GP) lb, vWF also interacts with GPIIb/IIIa, although the physiological relevance of this interaction is not completeley clear. In this paper, we have investigated the role of different size of vWF multimers in vWF-mediated platelet aggregation. Different size of vWF multimers were purified from human plasma through Sephacryl S-1000 column according to the method of Fowler et al. Fractions were analysed by SDS-agarose gel electrophoresis by the method of Ruggeri et al. When each fraction was examined for ristocetin cofactor activity (RCo), only larger multimers exhibited significant RCo. The maximum extent of ristocetin-induced platelet agglutination by larger multimers (10 μg/ml) was 80%, while that of intermediate and lower multimers at the same concentration was 20% and 0%, respectively. Each fraction was then added to washed platelet suspensions in the presence of 10 μM ADP and 0.3 mM CaCl2. Only larger multimers induced platelet aggregation, while intermediate and lower multimers failed to induce platelet aggregation. The maximum extent of aggregation in the presence of larger multimers (10 μg/ml) was 70% of that in the presence of fibrinogen instead. Similar experiments were peformed using platelet-rich plasma from a patient with afibrinogenemia in stead of washed normal platelets. ADP caused significant aggregation only when purified vWF larger multimers or fibrinogen was added. This vWF-mediated aggregation was completely inhibited by monoclonal antibody to GPIIb/IIIa (1 μg/ml) and synthetic peptide, Arg-Gly-Asp-Ser, (1 mM).Our results indicate that larger multimers of vWF play major roles in vWF interaction with GPIIb/IIIa.

scholarly journals Deficiency of C3a receptor attenuates the development of diabetic nephropathy

2019 ◽  
Vol 7 (1) ◽  
pp. e000817 ◽  
Author(s):  
Xiao-Qian Li ◽  
Dong-Yuan Chang ◽  
Min Chen ◽  
Ming-Hui Zhao
Keyword(s):  
Diabetic Nephropathy ◽  
T Cell ◽  
Adaptive Immunity ◽  
Renal Damage ◽  
Inflammatory Responses ◽  
Gene Knockout ◽  
Diabetic Mice ◽  
Pathogenic Role

ObjectiveDiabetic nephropathy (DN) is the leading cause of chronic kidney disease and end-stage renal disease. Emerging evidence suggests that complement activation is involved in the pathogenesis of DN. The aim of this study was to investigate the pathogenic role of C3a and C3a receptor (C3aR) in DN.Research design and methodsThe expression of C3aR was examined in the renal specimen of patients with DN. Using a C3aR gene knockout mice (C3aR−/−), we evaluated kidney injury in diabetic mice. The mouse gene expression microarray was performed to further explore the pathogenic role of C3aR. Then the underlying mechanism was investigated in vitro with macrophage treated with C3a.ResultsCompared with normal controls, the renal expression of C3aR was significantly increased in patients with DN. C3aR−/− diabetic mice developed less severe diabetic renal damage compared with wild-type (WT) diabetic mice, exhibiting significantly lower level of albuminuria and milder renal pathological injury. Microarray profiling uncovered significantly suppressed inflammatory responses and T-cell adaptive immunity in C3aR−/− diabetic mice compared with WT diabetic mice, and this result was further verified by immunohistochemical staining of renal CD4+, CD8+ T cells and macrophage infiltration. In vitro study demonstrated C3a can enhance macrophage-secreted cytokines which could induce inflammatory responses and differentiation of T-cell lineage.ConclusionsC3aR deficiency could attenuate diabetic renal damage through suppressing inflammatory responses and T-cell adaptive immunity, possibly by influencing macrophage-secreted cytokines. Thus, C3aR may be a promising therapeutic target for DN.

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