Effects of eprosartan on mitochondrial membrane potential and H2O2 levels in leucocytes in hypertension.

We investigated whether circulating leucocytes from hypertensive patients exhibit more spontaneous, stimulated hydrogen peroxide (H2O2) production and greater mitochondrial membrane potential (Deltapsi) than those from normotensive individuals. We also investigated the effects of oral treatment with the angiotensin II (AT II) type 1 receptor blocker eprosartan (600 mg day(-1)) on these markers of oxidative stress. In 25 hypertensive patients and 28 healthy volunteers, spontaneous H2O2 formation was measured by flow cytometry after preincubation of buffy coat-leucocytes from fresh peripheral venous blood at 37 degrees C with 2',7' dichlorofluorescein. Stimulation of H2O2 formation by circulating leucocytes was elicited by the addition of tert-butylhydroperoxide (tBHP). Deltapsi was determined by flow cytometry after the addition of tetramethylrhodamine methyl ester (TMRM). Compared with healthy individuals, lymphocytes from hypertensive patients exhibited higher Deltapsi (12.28+/-3.20 vs 16.25+/-2.88 arbitrary fluorescence units (AFU), respectively; P<0.001) and greater spontaneous H2O2 production (4.75+/-5.15 vs 8.98+/-9.97 AFU, respectively; P<0.05). tBHP stimulation was associated with higher H2O2 levels in circulating leucocytes in patients with uncorrected hypertension than in normotensive individuals. H2O2 overproduction was corrected by eprosartan treatment. These results suggest that oxidative stress could be important in the pathogenesis of hypertension. Furthermore, measurement of leucocyte oxidant activities may be useful for the evaluation of oxidative stress, which may be reduced with the use of antihypertensive drugs. Our results demonstrate that treatment of hypertension with eprosartan normalizes blood pressure and corrects oxidative disturbances, suggesting that leucocytes could be a target for this drug.

Platelet activation and red blood cell phosphatidylserine exposure evaluated by flow cytometry in patients with Behçet's disease: are they related to thrombotic events?

Behçet's disease (BD) is associated with an increased risk of venous and arterial thromboses that are associated with morbidity and mortality increase, although the mechanisms are not well established. In the present study, we used whole blood cytometry to determine the exposure of CD62 on the surface of platelets and the expression of phosphatidylserine (PS) on the surface of circulating red blood cells. Microparticle and microaggregate formation from platelets were also determined in a well-classified group of 72 patients (39 males, 33 females, aged 46.5 +/- 12.5 years) with BD, in comparison with a well-matched control group of 72 healthy volunteers. Results showed no differences in the above-mentioned parameters when BD patients and controls were compared. However, when we compared BD patients with/without thrombosis using these parameters, there were significant differences between both groups. BD patients with previous thrombosis had a higher percentage of circulating CD62-positive platelets and a higher number of circulating microaggregates than those without thrombosis, suggesting that platelet activation may be involved in the development of thrombotic events in these patients.

Utilidad clínica de la citometría de flujo para valorar la activación plaquetaria en diversas patologías / The clinical utility of flow cytometry in the study of platelet activation in pathology

En los últimos años, la citometría de flujo ha experimentado un desarrollo espectacular, que la confirma como una importante tecnología con un gran potencial analítico. Sus principales ventajas derivan del hecho de poder trabajar directamente con sangre entera, sin la activación artefactual plaquetaria que frecuentemente se produce por la manipulación de la muestra, y de poder detectar simultáneamente diversos antígenos en subpoblaciones celulares bien identificadas. Estas características permiten detectar la presencia de plaquetas activadas in vivo, y valorar el efecto in vitro y ex vivo de diversos inhibidores y agonistas sobre la función plaquetaria. Sin embargo, su aplicación al estudio de la activación plaquetaria en la práctica clínica habitual, está lejos de ser un hecho, por lo que parece conveniente revisar el estado actual del tema

Flow cytometry has emerged in the past years as an pivotal technology with a big analytical importance. This technique offers the ability to make analysis of platelets with very little manipulation and also it offers the possibility to study various antigens simultaneously on the platelet surface in whole blood. These characteristics allow to detect subpopulations of platelets activated in vivo and evaluate the effect of inhibitors andagonists in vitro and ex vivo. However, at the moment the clinical utility of flow cytometry in the platelet function study has been not well established and therefore this review describes the current state of this topic