Platelet Aggregation In Volunteers Research Articles

Cardioprotective properties of a novel enriched yogurt with inhibitors of Platelet Activating Factor (PAF)

AbstractPlatelet Activating Factor (PAF) is a pro-inflammatory mediator of atherogenesis. Food enriched with PAF inhibitors may have potential cardioprotective properties. In this attempt our group along with a well-known Greek dairy company incorporated bioactive ingredients (BAL) from olive-oil by-products, rich in PAF receptor specific inhibitors, into another typical food of the Mediterranean diet, namely yogurt. The aim of the present study was to evaluate the cardioprotective properties of the enriched yogurt in apparently healthy volunteers.Ninety two apparently healthy volunteers (35–65 years) were randomly allocated into three groups by block-randomization based on age, sex and BMI. The volunteers in Group A did not consume any yogurt. The volunteers of Group B consumed a non-enriched yogurt daily. The Group C volunteers ate daily an enriched yogurt. The intervention lasted 8 weeks. Volunteers’ adherence to the study protocol was assessed by two 24 h recalls every two weeks conducted by trained personnel. Blood and urine samples were collected at baseline, at 4th week and at 8th week of the intervention and biochemical and inflammatory markers were determined. In addition, platelet aggregation in volunteers’ platelet rich plasma against PAF, ADP and TRAP were measured and the results expressed as the concentration of the agonist that cause 50% of the maximum aggregation (EC50, efficient concentration fifty values).Among classical anthropometric and biochemical markers, only a decrease of blood pressure (systolic and diastolic) levels was observed (p0–8weeks < 0.05) in group B but with no clinical significance. Reduced levels of IL-10 was observed in group C compared to B both in the meantime (p4weeks = 0.01) and at the end of the intervention (p8weeks = 0.04). Furthermore, platelet sensitivity against PAF was only decreased (higher EC50 PAF,) in group C (p0–4weeks = 0.005 and p0–8weeks = 0.05). A trial effect was observed in the meantime among the three groups (p = 0.03).The consumption of the enriched yogurt led to attenuation of subclinical inflammation and platelet sensitivity to thrombotic stimuli in apparently healthy volunteers, indicating a potential cardioprotective role of PAF inhibitors.The work is funded by SYNERGASIA 2011 PROGRAMME. This Programme is co-funded by the European Regional Development Fund and National Resources, Project Code 11SYN-2-652.

Effects of desmopressin on platelet membrane glycoproteins and platelet aggregation in volunteers on clopidogrel

The use of clopidogrel is standard in interventional cardiology. Haemorrhage occurs in some patients, which implies a need for a non-transfusional therapy. Desmopressin showed its efficacy as an antidote of acetylsalicylic acid. In this trial the effects of desmopressin on platelet glycoproteins and the platelet's ability to aggregate under the influence of clopidogrel are studied. The trial was conducted as an open, prospective, single-centre, randomised pilot study with n=17 healthy volunteers in a parallel-group design. 1 h after an oral loading dose of 375 mg clopidogrel the effects of a single-dose of 300 mug of Octostim nasal spray (n=9) on platelet aggregation, activity of platelets on the density of membrane-bound receptors are measured. Ristocetin cofactor and platelet reactivity rose significantly after the administration of Octostim nasal spray with 31.9% and 5.3%, respectively (p=0.0329; p=0.0414). The ADP-induced platelet aggregation increased after the administration of Octostim nasal spray by approximately 20% (p=0.0564). The fraction of CD62- and CD63-positive platelets did not change after clopidogrel nor after desmopressin (p=0.4203; p=0.6774). The density of GPIIb/IIIa receptors per platelet did not change after desmopressin (p=0.9652). The density of GPIb/IX receptors per platelet rose after desmopressin without reaching the level of significance (p=0.0802). In the desmopressin group alone the receptor density rose by 5.5% (p=0.0783). The administration of desmopressin improved the primary haemostasis when given in addition to a clopidogrel therapy. Patients undergoing a heart catheter procedure with clopidogrel might benefit from the use of desmopressin when having a bleeding episode.