1013-111 Mechanisms Underlying the Morning Increase in Platelet Activation: Study of Whole Blood Platelet Flow Cytometry (original) (raw)
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Transfusion and Apheresis Science, 2010
Physical activity alters systemic levels of several angioregulatory cytokines that affect microvascular endothelial cells and can be assumed to influence vascular permeability. This may alter platelet release to the bone marrow microcirculation and thereby the levels of circulating platelets. We investigated effects of physical activity on angioregulatory chemokines (CXCL8, 9, 10 and 11) and peripheral blood platelet counts before and after intensive physical activity in young adults, and also compared platelet yields obtained by platelet apheresis performed in the morning and in the afternoon in 20 healthy donors. Physical activity increased serum CXCL10 levels and platelet counts but did not alter the other chemokine concentrations. In the apheresis donors, there was only a minor increase in platelet counts during the day, and the platelet yields did not differ significantly between platelet concentrates collected early in the morning and late in the afternoon. In conclusion, minor intra-individual variations in platelet counts do not seem to have major influence on platelet yields by platelet apheresis.
Abnormal diurnal changes in in-vivo platelet activation in patients with atherosclerotic diseases
Atherosclerosis, 1986
We measured the urinary excretion of beta-thromboglobulin in timed urine samples collected by 2 groups of healthy volunteers, (group I, n = 20, mean age 34 years, group II, n = 15, mean age 64 years) and by patients (n = 40) with symptomatic atherosclerotic diseases. Older healthy subjects were found to excrete high amounts of BTG in comparison to young subjects (302.25 + 50.61 vs 219.65 F 59.31 ng/day. P < 0.05). Higher (P < 0.01) levels of urinary BTG were observed in patients with coronary (427.61 + 179.96 ng/day), cerebral (422.13 + 223.2 ng/day) and peripheral (454.16 f 269.05 ng/day) arterial diseases and in diabetic patients with diffuse vascular complications (613.71 + 253.07 ng/day). The diurnal variability of BTG excretion, measured as coefficient of variation (C.V. %) of the mean daily excretion rate, was higher (P < 0.001) in atherosclerotic patients (70.59 f 26.57) as compared with the similar values observed in the control groups of young (32.05 f 14.54) and older subjects (26.38 + 8.4). Comparable diurnal variabilities of the creatinine excretion rate were observed in the control groups and in patients. These data indicated that in vivo platelet activation may occur in atherosclerotic patients with a distinctive high fluctuation rate.
Impaired circadian variation of platelet activity in patients with sleep apnea
Sleep & breathing = Schlaf & Atmung, 2011
BACKGROUND: Cardiovascular diseases are frequent in patients with obstructive sleep apnea (OSAS). There is evidence that the day-night pattern of myocardial infarction and sudden cardiac death observed in the general population is altered in patients with OSAS. This study investigates potential abnormalities in the circadian profiles of platelet activity in OSAS. METHODS: We studied 37 patients with OSAS [7 of whom were also studied after 3 months on continuous positive airway pressure (CPAP) treatment] and 11 controls. In each subject, we obtained six different blood samples during 24-h period (2200, 0200, 0600, 1000, 1400, and 1800 hours). Platelet activity was determined by flow cytometry immediately after sampling. RESULTS: We found that nocturnal platelet activity was significantly increased in patients with OSAS (p = 0.043) and that effective treatment with CPAP decreased platelet activity in these patients but differences just failed to reach statistical significance (p = 0.0...
Water Intake Before Bed Decreases the Morning Platelet Activity in At-Risk Patients
Journal of Cardiology and Clinical Practice, 2021
Aim of the Study Our study was designed to show that determine whether or not intake of 400 mL of water before bed has an effect of platelet activity in the morning. Method The study was a project conducted from April to August 2018 in a Prague-based clinic of internal medicine. The study protocol was
The Diurnal Tick Tockery of Platelet Biology
Circadian (∼24 hours) clocks are ubiquitous in nature and are important regulators of behaviour, physiology and metabolism. Circadian clocks can synchronise biological processes with environmental cycles, buffer biological systems to maintain homeostasis and partition mutually antagonistic processes to different temporal spaces within the daily cycle. Clocks act cell-autonomously (intrinsically) and systemically (extrinsically) to coordinate whole organism biology and there is epidemiological evidence indicating that chronic disruption of behavioural rhythms increases the risk of developing cancer and cardiovascular disease. Although the genetic mechanism of the mammalian clock has been largely deciphered, the physiological relevance of clocks often remains elusive. Findings from humans and animal models suggest that the circadian clock and diurnal rhythms have an important role in megakaryopoiesis and the risk of a cardiovascular event. This short review will introduce the mammalian circadian clock and discuss how circadian clocks and diurnal rhythms influence platelet production and function.
Cardiology journal, 2008
Numerous trials have reported on the morning increase in the occurrence of myocardial infarction, stroke and sudden cardiac death. Similarly, enhanced morning platelet aggregation has been observed in healthy individuals and in subjects with coronary artery disease without adequate antiplatelet treatment. The purpose of the study was to assess circadian variation in platelet aggregation in patients with first ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary interventions (pPCI) and dual antiplatelet therapy. Fifteen consecutive patients (12 men and 3 women) were prospectively recruited into the study. Blood samples were collected at 6.00 a.m., 10.00 a.m., 2.00 p.m. and 7.00 p.m. on the third day of hospitalization. Aggregation in response to arachidonic acid and adenosine diphosphate (ADP) was assessed in the whole blood on a new generation impedance aggregometer. A morning increase of 75% in ADP-dependent platelet aggregation was noted in the st...
Diurnal variation in platelet inhibition by clopidogrel
Platelets, 2011
Morning increase in the occurrence of myocardial infarction, stroke and sudden cardiac death is a well-recognized phenomenon, which is in line with a morning enhancement of platelet aggregation. We investigated whether platelet inhibition during clopidogrel and aspirin therapy varies during the day. Fifty-nine consecutive patients (45 men and 14 women) with first ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary interventions (pPCI) on dual antiplatelet therapy were prospectively enrolled into the study. Blood samples were collected 4 days after start of clopidogrel treatment at 6.00 a.m., 10.00 a.m., 2.00 p.m. and 7.00 p.m. Arachidonic acid and adenosine diphosphate (ADP)-induced platelet aggregation were assessed by impedance aggregometry. Platelet inhibition by clopidogrel was lowest in the midmorning: median ADP-induced platelet aggregation was 55%, 17% and 27% higher at 10.00 a.m. compared to 6.00 a.m., 2.00 p.m. and 7.00 p.m., respectively ( p < 0.002). Nonresponsiveness to clopidogrel defined according to the device manufacturer was 2.4-fold more frequent in the midmorning than in the early morning. We observed a more pronounced midmorning increase in ADP-induced platelet aggregation in diabetic patients when compared to non-diabetics. In contrast, no diurnal variation in the antiplatelet effect of aspirin was observed. In conclusion, in patients presenting with STEMI undergoing pPCI, platelet inhibition by clopidogrel is less strong in the midmorning hours. This periodicity in platelet aggregation in patients on dual antiplatelet therapy should be taken into consideration when assessing platelet function in clinical studies.
Circadian variation of ticagrelor-induced platelet inhibition in healthy adulty
European heart journal. Cardiovascular pharmacotherapy, 2018
The circadian variation of platelet aggregation is well demonstrated. However, whether this has an impact on antiplatelet inhibition therapy is poorly documented. We aimed to observe whether ticagrelor-induced platelet inhibition follows a circadian rhythm. The study included 25 healthy volunteers (11 female;14 male). Blood samples were collected every 4 hours. Ticagrelor was added in vitro at a concentration that provided 50% inhibition of the maximum response using the VerifyNow System Platelet Reactivity Test® thus avoiding any bias induced by circadian gastro-intestinal absorption. Platelet aggregation testing was subsequently performed using the VerifyNow. Circadian changes in total platelet count, percentage of platelets inhibition, Von Willebrand activity and volunteers' physiological parameters were analyzed by fitting individuals' data to a sine curve with a 24-hour period. Volunteers' physiological parameters (heart rate[bpm], systolic/diastolic blood pressure[...