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With the diet, we ingest nutrients capable of modulating platelet function, which plays a crucial role in developing cardiovascular events, one of the leading causes of mortality worldwide. Studies that demonstrate the antiplatelet and antithrombotic potential of bioactive compounds are vital to maintaining good cardiovascular health. In this work, we evaluate the flavonol isorhamnetin's antiplatelet effect on human platelets, using collagen, thrombin receptor activator peptide 6 (TRAP-6), and phorbol myristate acetate (PMA) as agonists. Isorhamnetin induced a significant inhibition on collagen- and TRAP-6-induced platelet aggregation, with half-maximum inhibitory concentration (IC50) values of 8.1 ± 2.6 and 16.1 ± 11.1 µM, respectively; while it did not show cytotoxic effect. Isorhamnetin reduced adenosine triphosphate levels (ATP) in platelets stimulated by collagen and TRAP-6. We also evidenced that isorhamnetin's antiplatelet activity was related to the inhibition of mitochondrial function without effect on reactive oxygen species (ROS) levels. Additionally, we investigated isorhamnetin's effect on thrombus formation in vitro under flow conditions on the damaged vessel wall. In this context, we demonstrate that isorhamnetin at 20 µM induced a significant inhibition on platelet deposition, confirming its antithrombotic effect. Our findings corroborate the antiplatelet and antithrombotic potential of isorhamnetin present in many foods of daily consumption.

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In a global context of advanced aging, geriatric diseases such as frailty syndrome face challenges in the search for biomarkers and preventive strategies. Frailty has been associated with atherothrombotic pathologies. Circulating microvesicles (cMVs), phospholipid-rich vesicles with a size of 0.1-1.0 µm, have been shown to participate in atherothrombosis onset and progression. We have hypothesized that cMVs from platelets, and vascular and immune cells, are increased in frail older adults. To verify this, a prevalent-case control study was designed with 28 frail older and 27 nonfrail older adults older than 64 years. Frailty was defined by Fried's phenotype. Total cMVs, annexin V positive (AV+)-cMVs, and annexin V negative (AV- )-cMVs derived from blood and vascular cells were measured by flow cytometry. In the analysis of total cMVs, the frail group presented higher levels of CD14+ /CD142+ (p = .042), CD41a+ /CD142+ (p = .041), and CD56+ (p = .025), CD14+ cMVs (p = .043), and CD16+ /CD14+ (p = .019) cMVs levels. Within the phosphatidylserine-exposing cMVs (AV+ ), the frail group showed higher CD14+ /AV+ (p = .044), CD9+ /AV+ (p = .031), P2RY12+ /AV+ (p = .028), and CD235a+ /AV+ (p = .043) cMVs concentrations. Finally, within AV- cMVs, the frail group showed higher CD142+ /CD41a+ /AV- cMVs concentrations originated from platelets (p = .027), CD56+ /AV- originated from natural killer cells (p = .022), and CD34+ /AV- cMVs from hematopoietic stem cells (p = .037). In summary, frail older adults present higher concentrations of platelet-, leukocyte-, and hematopoietic cell-derived cMVs compared to robust age-matched older adults. These cMVs may be involved in the deregulation of the immune system, endothelial damage, and increased risk of thrombosis associated with frailty.

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BACKGROUND: Guanosine is a natural product and an endogenous nucleoside that has shown to increase during myocardial ischemia. Platelets are critically involved in ischemic coronary events. It remains unknown, however, whether guanosine may affect platelet activation and function. We sought to investigate the potential antiplatelet and antithrombotic properties of guanosine and decipher the mechanisms behind. METHODS: We firstly assessed the effects of guanosine on platelet activation/aggregation upon stimulation with several platelet agonists including adenosine diphosphate (ADP), collagen, arachidonic acid (AA), and TRAP-6. Guanosine antithrombotic potential was also evaluated both in vitro (Badimon perfusion chamber) and in vivo (murine model). In addition we assessed any potential effect on bleeding. At a mechanistic level we determined the release of thromboxane B2, intraplatelet cAMP levels, the binding affinity on platelet membrane, and the activation/phosphorylation of protein kinase A (PKA), phospholipase C (PLC) and PKC. RESULTS: Guanosine markedly inhibited platelet activation/aggregation-challenged by ADP and, although to a lesser extent, also reduced platelet aggregation challenged by collagen, AA and TRAP-6. Guanosine significantly reduced thrombus formation both in vitro and in vivo without significantly affects bleeding. Guanosine antiplatelet effects were associated with the activation of the cAMP/PKA signaling pathway, and a reduction in thromboxane B2 levels and PLC and PKC phosphorylation. The platelet aggregation and binding affinity assays revealed that guanosine effects on platelets were mediated by adenosine. CONCLUSION: Guanosine effectively reduces ADP-induced platelet aggregation and limits thrombotic risk. These antithrombotic properties are associated with the activation of the cAMP/PKA signaling pathway.

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The endothelium helps to maintain the normal structure and homeostasis of the vasculature. However, chronic exposure to cardiovascular (CV) risk factors causes endothelial dysfunction, a phenomenon that is characterized by inflammation, reduced bioavailability of nitric oxide (NO) and a prothrombotic state. Epidemiological studies have shown that regular consumption of fruits and vegetables reduces CV risk, which has caused interest in knowing the bioactive compounds and the mechanisms involved. Among the components that protect the endothelium are antioxidants (vitamin C, vitamin E and poly phenols) and polyunsaturated fatty acids. Vitamin C and E promote vasodilatation protecting NO by blocking the reactive oxygen species (ROS). Poly phenols improve endothelial function primarily by increasing levels of NO, and inhibition of angiogenesis and platelet activation. Diets rich in poly-unsaturated fatty acids have shown beneficial effects by reducing the gene expression of cyclooxygenase-2 and the expression of cell adhesion molecules. This review mainly highlights the current understanding of endothelial dysfunction and the protective effect of endothelial cells by bioactive components of fruits and vegetables.

El endotelio normal ayuda a mantener la estructura y la hemostasia vascular. Sin embargo, la exposición crónica a factores de riesgo cardiovascular (CV) produce disfunción endotelial, fenómeno que se caracteriza por inflamación, disminución en la biodisponibilidad de óxido nítrico (NO) y un estado protrombótico. Estudios epidemiológicos han demostrado que el consumo regular de frutas y hortalizas disminuye el riesgo CV, lo que ha causado interés en conocer los compuestos bioactivos y los mecanismos involucrados. Entre los componentes que protegen el endotelio se encuentran las moléculas antioxidantes (vitamina C, vitamina E y polifenoles) y ácidos grasos poliinsaturados. Las vitaminas C y E favorecen la vasodilatación protegiendo el NO al bloquear las especies reactivas del oxigeno (ROS). Los polifenoles mejoran la función endotelial principalmente por el aumento de los niveles de NO, y la inhibición de la angiogénesis y de la activación plaquetaria. Dietas ricas en ácidos grasos poliinsaturados han mostrado efectos beneficiosos, mediante la reducción de la expresión géni-ca de la ciclooxigenasa-2 y de la expresión de moléculas de adhesión celular. Esta revisión principalmente señala los conocimientos actuales de la disfunción endotelial y el efecto protector de las células endoteliales por componentes bioactivos de frutas y hortalizas.

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