scholarly journals Alpha-tocopherol, an effective inhibitor of platelet adhesion

Blood ◽  
1989 ◽  
Vol 73 (1) ◽  
pp. 141-149 ◽  
Author(s):  
J Jandak ◽  
M Steiner ◽  
PD Richardson
Keyword(s):  
Vitamin E ◽  
Platelet Adhesion ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Flow Chamber ◽  
Alpha Tocopherol ◽  
Tocopherol Concentration ◽  
Average Decrease ◽  
Platelet Adherence

Abstract Platelet adhesiveness was tested ex vivo in a group of six normal individuals receiving varying doses of alpha-tocopherol. Adhesion to glass slides coated with fibronectin, collagen, fibrinogen, or plasma proteins was studied by perfusing platelet-rich plasma through a flow chamber that allowed time- and space-resolved observations of platelet adhesion. Platelet adherence was measured in an area of parallel flow lines and low shear rate under standardized conditions before and after dietary supplementation with vitamin E at doses of 200 and 400 IU/d. Platelet adherence differed in magnitude depending on the adhesive surface. There was a distinct preference of platelets to adhere to sites that had been previously occupied. A remarkable decrease in platelet adherence was observed after vitamin E supplementation. The average decrease in adhesion after 2 weeks of 200 IU vitamin E was 75%. After 2 weeks of 400 IU vitamin E, platelet adhesion was reduced by 82%. The inhibitory activity of alpha-tocopherol was dose dependent and correlated well with the increase in alpha-tocopherol concentration in platelets after supplementation. Scanning electron microscopy revealed a striking decrease of pseudopodium formation in alpha-tocopherol- enriched platelets. Our results suggest that vitamin E may also be an effective antiadhesive agent in vivo.

Alpha-tocopherol, an effective inhibitor of platelet adhesion

Blood ◽  
1989 ◽  
Vol 73 (1) ◽  
pp. 141-149
Author(s):  
J Jandak ◽  
M Steiner ◽  
PD Richardson
Keyword(s):  
Vitamin E ◽  
Platelet Adhesion ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Flow Chamber ◽  
Alpha Tocopherol ◽  
Tocopherol Concentration ◽  
Average Decrease ◽  
Platelet Adherence

Platelet adhesiveness was tested ex vivo in a group of six normal individuals receiving varying doses of alpha-tocopherol. Adhesion to glass slides coated with fibronectin, collagen, fibrinogen, or plasma proteins was studied by perfusing platelet-rich plasma through a flow chamber that allowed time- and space-resolved observations of platelet adhesion. Platelet adherence was measured in an area of parallel flow lines and low shear rate under standardized conditions before and after dietary supplementation with vitamin E at doses of 200 and 400 IU/d. Platelet adherence differed in magnitude depending on the adhesive surface. There was a distinct preference of platelets to adhere to sites that had been previously occupied. A remarkable decrease in platelet adherence was observed after vitamin E supplementation. The average decrease in adhesion after 2 weeks of 200 IU vitamin E was 75%. After 2 weeks of 400 IU vitamin E, platelet adhesion was reduced by 82%. The inhibitory activity of alpha-tocopherol was dose dependent and correlated well with the increase in alpha-tocopherol concentration in platelets after supplementation. Scanning electron microscopy revealed a striking decrease of pseudopodium formation in alpha-tocopherol- enriched platelets. Our results suggest that vitamin E may also be an effective antiadhesive agent in vivo.

ETHANOL INHIBITS RABBIT PLATELET RESPONSES TO COLLAGEN IN VITRO BUT DOES NOT AFFECT RABBIT PLATELET ADHERENCE TO DE-ENDOTHELIALIZED A0RTAE IN VIVO

1987 ◽  
Author(s):  
M L Rand ◽  
H M Groves ◽  
R L Kinlough-Rathbone ◽  
M A Packham ◽  
J F Mustard
Keyword(s):  
Coronary Heart Disease ◽  
Heart Disease ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Platelet Adherence ◽  
Induced Aggregation

Epidemiological studies indicate that moderate consumption of alcohol is associated with a reduced risk of coronary heart disease, but it is not known whether inhibition of platelet functions by ethanol is involved. We studied the effects of ethanol on rabbit platelet responses to collagen in vitro and in vivo. Addition of ethanol (4 mg/ml) to suspensions of washed platelets prelabelled with [14c]serotonin inhibited aggregation and secretion in response to low (0.4 μg/ml) concentrations of acid soluble collagen (14% secretion without ethanol, 3% secretion with ethanol). With a higher concentration of collagen (1.25 μg/ml), 4 mg/ml ethanol had no inhibitory effect. The inhibitory effect of ethanol on collagen-induced aggregation was also observed in citrated platelet-rich plasma (c-PRP) to which ethanol was added in vitro and in c-PRP from rabbits given ethanol acutely by gavage (3.5 g/kg) 30 min before blood sampling. The accumulation of [51cr]-labeled platelets on the subendothelium of rabbit aortae de-endothelialized with balloon catheters was measured in vivo in rabbits given ethanol (blood ethanol concentration at time of vessel wall injury: 4.1 ± 0.2 mg/ml, mean ± S.E., n=6). Ten min after de-endothelialization, there was no difference between the number of platelets adherent per square mm of injured aorta of control rabbits (39,400 ± 2,600, mean ± S.E., n=6) and intoxicated rabbits (36,800 ± 3,700, mean ± S.E., n=6). Thus, although ethanol inhibits platelet aggregation and secretion in response to collagen in vitro and ex vivo, it does not alter platelet adherence to the subendothelium, including its constituent collagen, in vivo. Therefore, it is unlikely that ethanol exerts its beneficial effects against coronary heart disease by altering the initial adherence of platelets to injured vessel walls.

Combined effects of vitamin E (alpha-tocopherol) and cisplatin on the growth of murine neuroblastoma in vivo

1988 ◽  
Vol 24 (11) ◽  
pp. 1751-1758 ◽  
Author(s):  
Kohji Sue ◽  
Akira Nakagawara ◽  
Shin-Ichi Okuzono ◽  
Takahiko Fukushige ◽  
Keiichi Ikeda
Keyword(s):  
Vitamin E ◽  
Alpha Tocopherol ◽  
Combined Effects ◽  
Murine Neuroblastoma

Abstract 54: ML355 in Prevention of Thrombosis in vivo with Minimal Effects on Hemostasis

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Reheman Adili ◽  
Katherine Mast ◽  
Michael Holinstat
Keyword(s):  
Ex Vivo ◽  
Platelet Reactivity ◽  
Thrombus Formation ◽  
Flow Chamber ◽  
Human Platelets ◽  
Mass Spectrometry Analysis ◽  
Vessel Occlusion ◽  
Spectrometry Analysis ◽  
Thrombosis Model

12-lipoxygenase (12-LOX) has been demonstrated to regulate platelet function, hemostasis, and thrombosis ex vivo , supporting a key role for 12-LOX in regulation of in vivo thrombosis. While pharmacologically targeting 12-LOX in vivo has been a challenge to date, the recent development of the 12-LOX selective inhibitor, ML355, as an effective antiplatelet therapeutic in vivo was assessed. ML355 potently inhibited thrombin and other agonist-induced platelet aggregation ex vivo in washed human platelets and inhibited downstream oxylipin production of platelet 12-LOX as confirmed by Mass spectrometry analysis. Ex vivo flow chamber assays confirmed that human platelet adhesion and thrombus formation at arterial shear over collagen was attenuated in human whole blood treated with ML355 to a greater extent compared to aspirin. In vivo , PK assessment of ML355 showed reasonable 12-LOX plasma levels 12 hours following administration of ML355. FeCl 3 -induced injury of the mesenteric arterioles resulted in less stable thrombi in 12-LOX -/- mice and ML355-treated WT mice resulting in impairment of vessel occlusion. Additionally, ML355 dose-dependently inhibited laser-induced thrombus formation in the cremaster arteriole thrombosis model in WT, but not in 12-LOX -/- mice. Importantly, hemostatic plug formation and bleeding following treatment with ML355 were not affected in response to laser ablation on the saphenous vein or in a cremaster microvasculature laser-induced rupture model. Our data strongly supports 12-LOX as a key determinant of platelet reactivity in vivo and inhibition of platelet 12-LOX with ML355 may represent a new class of antiplatelet therapeutics.

5 Cold stored platelets correct cardiac surgery induced platelet dysfunction

2021 ◽  
Vol 167 (3) ◽  
pp. e1.5-e1
Author(s):  
Tom Scorer ◽  
Andrew Mumford
Keyword(s):  
Cardiac Surgery ◽  
Shelf Life ◽  
Platelet Function ◽  
Platelet Transfusion ◽  
Ex Vivo ◽  
Flow Chamber ◽  
Platelet Dysfunction ◽  
Current Standard ◽  
Blood Samples

IntroductionPlatelet dysfunction (thrombocytopathy) is a major problem in the bleeding patient and increases morbidity and healthcare costs. The thrombocytopathy resulting from cardiopulmonary bypass (CPB) can be used to study therapies targeted to improve outcomes in other scenarios, such as trauma. Platelet transfusion is used widely to correct thrombocytopathy. However, the current standard, room temperature stored platelets (RTP) have several disadvantages including; short shelf life, risk of bacterial contamination and deterioration in platelet function during storage. Cold stored platelets (CSP) are a potential alternative product with longer shelf life, reduced contamination risk and better-preserved platelet function.MethodsUsing ex vivo mixing studies, we investigated whether CSP were better able to reverse the thrombocytopathy associated with cardiac surgery than RTP. Blood samples were collected from 20 cardiac surgery patients. Donor platelets were split into two bags and stored at either 4°C (CSP), or 22°C (RTP) for up to seven days. The donor platelets were mixed with the patient blood samples to simulate platelet transfusion. The mixed samples were analysed using the TEG 5000 and using a collagen coated flow chamber at arterial shear. Patient samples were analysed alongside healthy controls (n = 20).ResultsAfter mixing the patient samples with CSP, the TEG R times were shorter than in samples mixed with RTP (p<0.0001), indicating more rapid initiation of clot formation. In the flow chamber experiments, the clot volume was greater in the patient samples mixed with CSP compared with samples mixed with RTP (p<0.0001).ConclusionsThese findings suggest that CSP, but not RTP can partially reverse the thrombocytopathy associated with cardiac surgery ex vivo, at clinically relevant mixing volumes. Reversal of thrombocytopathy by mixing CSP was greatest in the arterial shear model, which may indicate superior in vivo efficacy that requires confirmation in clinical trials.* this abstract presentation was awarded First Place.

scholarly journals Effects of Sodium Nitroprusside on Platelet Adhesion, Subsequent Aggregation and Vasoconstriction

1977 ◽  
Author(s):  
H.R. Baumgartner
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Sodium Nitroprusside ◽  
Platelet Adhesion ◽  
Ex Vivo ◽  
Balloon Catheter ◽  
Strong Inhibitor ◽  
Induced Aggregation

Sodium nitroprusside (SNP), a potent vasodilator, has shown beneficial effects in acute myocardial infarction. Since platelets may play an important role in the pathogenesis of myocardial infarction, the effect of SNP on their interaction with rabbit aorta subendothelium was investigated in vivo and under controlled blood flow conditions ex vivo and in vitro.One iliac artery and the abdominal aorta were denuded of endothelium by balloon catheter injury during infusion of glucose, SNP at 6 or 12 μg/kg/min in groups of 12, 6 and 7 rabbits respectively. The aorta and their branches were perfuse-fixed under controlled pressure 10 min after denudation. Morphometric evaluation showed dose-dependent and significant (2p < 0.01 or 0.001) inhibition of platelet spreading, adhesion and aggregation. The latter was abolished at the higher dose of SNP. Denudation and subsequent platelet adhesion caused strong vasoconstriction (2p < 0.001) which was inhibited by SNP (2p < 0.01).By exposure of subendothelium to either citrated blood or native blood in a flow chamber (2000 sec-1 shear rate) strong inhibition of spreading and adhesion-induced aggregation was again demonstrated at 6 and 12 μg/kg/min SNP. In vitro, adhesion-induced aggregation was completely abolished after the addition of SNP to rabbit (at 20 μg/ml) or human blood (2 μg/ml). 1 μg/ml PGE1 was needed to induce a similar inhibitory effect.Thus SNP is a strong inhibitor of platelet function and of injury + platelet induced vasoconstriction. These findings may explain its beneficial effect in acute myocardial infarction.

scholarly journals Talin is required for integrin-mediated platelet function in hemostasis and thrombosis

2007 ◽  
Vol 204 (13) ◽  
pp. 3103-3111 ◽  
Author(s):  
Brian G. Petrich ◽  
Patrizia Marchese ◽  
Zaverio M. Ruggeri ◽  
Saskia Spiess ◽  
Rachel A.M. Weichert ◽  
...  
Keyword(s):  
Platelet Adhesion ◽  
Ex Vivo ◽  
Focal Adhesions ◽  
Β1 Integrin ◽  
Normal Morphology ◽  
And Function ◽  
Specific Deletion

Integrins are critical for hemostasis and thrombosis because they mediate both platelet adhesion and aggregation. Talin is an integrin-binding cytoplasmic adaptor that is a central organizer of focal adhesions, and loss of talin phenocopies integrin deletion in Drosophila. Here, we have examined the role of talin in mammalian integrin function in vivo by selectively disrupting the talin1 gene in mouse platelet precursor megakaryocytes. Talin null megakaryocytes produced circulating platelets that exhibited normal morphology yet manifested profoundly impaired hemostatic function. Specifically, platelet-specific deletion of talin1 led to spontaneous hemorrhage and pathological bleeding. Ex vivo and in vitro studies revealed that loss of talin1 resulted in dramatically impaired integrin αIIbβ3-mediated platelet aggregation and β1 integrin–mediated platelet adhesion. Furthermore, loss of talin1 strongly inhibited the activation of platelet β1 and β3 integrins in response to platelet agonists. These data establish that platelet talin plays a crucial role in hemostasis and provide the first proof that talin is required for the activation and function of mammalian α2β1 and αIIbβ3 integrins in vivo.

scholarly journals Selenium and α-tocopherol content in eggs produced by hens that were fed diets supplemented with selenomethionine, sodium selenite and vitamin E

2010 ◽  
Vol 55 (No. 9) ◽  
pp. 388-397 ◽  
Author(s):  
M. Skřivan ◽  
I. Bubancová ◽  
M. Marounek ◽  
G. Dlouhá
Keyword(s):  
Vitamin E ◽  
Sodium Selenite ◽  
Thiobarbituric Acid ◽  
Basal Diet ◽  
Tocopherol Content ◽  
Alpha Tocopherol ◽  
Dietary Vitamin ◽  
Tocopherol Concentration ◽  
The Third ◽  
Egg Yolks

The effect of supplementing dietary selenium (Se) and vitamin E was investigated in 330 24-week-old laying hens. The hens were fed a basal diet containing Se and &alpha;-tocopherol at 0.11 and 26 mg/kg, respectively, or a diet supplemented with Se at 0.3 mg/kg and vitamin E between 0 and 625 mg/kg. Se was supplied as Se-methionine or sodium selenite. The eggs were collected for analysis during the third, seventh and eleventh weeks of the experiment. Supplementation of either form of Se significantly increased the Se concentration in egg yolks and whites, with a more pronounced effect caused by Se-methionine. The egg yolk &alpha;-tocopherol concentration paralleled the dietary &alpha;-tocopherol concentration. At a high dietary &alpha;-tocopherol concentration (632 mg/kg), the retinol content in egg yolks from hens fed Se-methionine increased significantly. Supplementation of Se-methionine significantly increased the &alpha;-tocopherol content in the eggs in the third and seventh weeks of the experiment. A moderate decrease in yolk cholesterol was observed in hens fed Se-methionine and &alpha;-tocopherol at 119 mg/kg. The concentration of products from lipid peroxidation (thiobarbituric acid-reactive substances, TBARS) in egg yolks increased marginally during the refrigerated storage of the eggs for 2 weeks. The effect of dietary vitamin E on TBARS formation was generally small, although a more significant effect was observed at the highest dose tested.

scholarly journals Sequestration of Vitamin E by Liver Fat in vivo, in vitro and in Women with Hepato-steatosis

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1696-1696
Author(s):  
Pierre-Christian Violet ◽  
Ifechukwude Ebenuwa ◽  
Stacey Chung ◽  
Jeffrey Atkinson ◽  
Danny Manor ◽  
...  
Keyword(s):  
Liver Disease ◽  
Vitamin E ◽  
High Fat Diet ◽  
Alpha Tocopherol ◽  
Liver Fat ◽  
Slight Reduction ◽  
High Fat ◽  
High Vitamin

Abstract Objectives Hepato-steatosis (HS) due to obesity is now the most common cause of chronic liver disease in the Americas and Western Europe. The only means to prevent disease is avoidance of obesity. α-Tocopherol at doses of 800 I.U. daily was reported to have partial treatment effects for NASH. Because alpha tocopherol is a fat-soluble vitamin, we hypothesized that excess fat in liver, as found in HS, could act unintentionally sequester vitamin E, thereby altering its normal physiology and contributing to development of NASH. Using oral and intravenous deuterated tocopherols, evidence showing HS altered a-tocopherol physiology was reported based on pharmacokinetics studies in obese women with HS. Here we further tested the sequestration hypothesis in vitro, and in vivo. Methods In vitro, we investigated effects of fat on intracellular vitamin E localization. Control human and mouse hepatocytes and hepatocytes pre-loaded with fat were incubated with fluorescent α-tocopherol (BDP-α-tocopherol). In vivo experiments were performed using mice fed a high fat diet with different vitamin E doses. Results Compared to controls, fat- loaded cells contained more a-tocopherol, and BDP-a-tocopherol was specifically localized into intracellular fat droplets. In cells incubated with BDP a-tocopherol, we found that fat loading decreased a-tocopherol release. Induced expression of TPP, which mediates vitamin E intracellular disposition under normal conditions, was not observed in fat loaded cells, further confirming vitamin E was trapped in fat. Livers of mice fed high fat diet had more vitamin E compared to controls. By further increasing vitamin E content of the high fat diet, we observed a reduction in liver size and liver fat in the high vitamin E group. Using a mouse metabolic chamber, we observed a slight reduction of oxygen consumption rate in the high vitamin E group compared to controls. Conclusions Considered together, these findings imply that fat in the liver may produce unrecognized hepatic vitamin E sequestration, which could drive liver disease. These results are consistent with the possibility that increased vitamin E intake might, if begun at an early stage, restore vitamin E physiology, potentially decreasing or preventing progression of HS to NASH. Funding Sources NIH intramural program (DK053213–14).

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