Producción de prostaciclina en arteria radial de diabéticos: comparación con la vena safena y arteria mamaria interna y su relevancia en el pronóstico de estos bypass coronarios / Prostacyclin production in internal mammary ano radial arteries and saphenous veins of diabetic and non diabetic subjects

Background: Myocardial revascularization surgery has used several vessels as coronary grafts including internal mammary and radial arteries which have a better prognosis than saphenous vein. Their long-term patency has been associated with the reléase of endothelium vasodilator and anti-aggregating producís such as prostacyclin. Diabetes induces endothelial dysfunction and a high number of diabetics require revascularization. Aim: To assess the capacity to synthesize prostacyclin of different vessels from diabetics. Material and methods: Internal mammary and radial arteries and saphenous veins obtained from 10 diabetic and 10 non diabetic patients subjected to coronary artery bypass surgery were studied. The capacity to synthesize prostacyclin was assessed in these vessels measuríng its hydrolysis product, the 6-keto-PGFla by radioimmunoassay. Results: Internal mammary arteries and saphenous veins from diabetics synthesized a lower amount of prostacyclin than those from non-diabetics. The radial artery produced similar amounts of prostacyclin in both groups. This response was associated with an increase of the conversión of the precursor arachidonic acid to prostacyclin. The saturating concentrations of this acid required to achieve the maximal stimulation were higher in the radial artery (20 µM) than in the internal mammary artery and saphenous vein (10 µM), suggesting that the enzymatic activity of the radial artery was not affected by diabetes. Conclusions: The radial artery appears as the best replacement vessel for coronary surgery in diabetics. Its favorable biochemical profile and potential lower long-term occlusion rate may be relevant for a better prognosis of myocardial revascularization in these patients.

Influence of the estrous cycle on the norepinephrine-induced contraction of rat aorta: relationship to vascular prostanoids biosynthesis

Since ovarian sex steroids (estradiol and progesterone) may affect both blood pressure and prostanoids synthesis, and because prostaglandin-E2 (PGE2) and prostacyclin (PGI2) can modulate the vascular action of pressor hormones, we investigated the vascular reactivity to norepinephrine during the estrous cycle of the rat. In addition, we determined the vascular biosynthesis of PGE2 and 6-keto-PGF1 alpha (the stable metabolite of PGI2) at different stages of the estrous cycle. Cumulative dose-response curves were obtained by a stepwise increase in the concentration of norepinephrine. The contraction of thoracic aortic rings induced by norepinephrine did not change significantly between estrus, metestrus and diestrus. However, aortic rings obtained on proestrus showed a significant reduction in the maximal contraction (Emax) induced by norepinephrine (p < 0.001). In addition, we found significant increases in vascular synthesis of PGE2 and PGI2 on proestrus (p < 0.001). These results indicate that vascular reactivity and vascular prostanoids synthesis are influenced by the hormonal changes occurring during the estrous cycle of normal female rats. It is possible that prostanoids generated locally may play an important role in the regulation of vasomotor tone in the systemic vascular bed throughout the estrous cycle

Producción comparativa de prostaciclina en arteria epigástrica inferior, arteria mamaria interna y vena safena: implicancias en el pronóstico de la revascularización miocárdica / Prostacycline production by the inferior epigastric artery, compared to the internal mammary artery and the saphenous vein

Se usó un sistema in vitro para medir la producción de PG12 en anillos aislados de la arteria mamaria interna, la arteria epigástrica inferior y la vena safena obtenidos en 5 pacientes durante cirugía de revascularización. La muestras fueron incubadas en solución Krebs'Ringer a pH 7.4. Por radioinmuoensayo (Amersham) se midió el 6-keto-PGF la, metabolito de PG12 en alicuotas del sobrenadante. La producción de arterias epigástrica fue 12,5 2,0 ng/mg/30 min, la de arteria mamaria interna 9,3 1,7 y la de vena safena5,1 0,7 (p 0,01). Por lo tanto, la arteria epigástrica inferior produce PG12 en cantidades similares a las de la arteria mamaria interna y considerablemente mayores que las de la vena safena. Ello podría traducirse en un mejor pronóstico de los puentes coronarios efectuados con arteria epigástrica comparados con las de la vena safena

Human centrifugation machine a physiological stimulator of endogenous prostaglandin synthesis

Un nuevo modelo de centrífuga humana de la síntesis de prostaglandinas endógenas es presentado. Las diferentes aplicaciones terapéuticas de esta máquina fueron demostradas en linfedema, arteriopatías obstructivas periféricas, síndrome de distrofia simpática refleja, retinopatía diabética plana o background y enfermedad coronaria

Vascular prostacyclin production in andean women with pregnancy-induced hypertension

Although prostacyclin (PGI2) production in the umbilical artery is known to be reduced in prognancy-induced hypertension (PIH), little information is available about its production in maternal vascular tissues. We measured 6-keto-prostaglandin F 1* generation in the umbiblical and comentum arteries of 24 Andean women divided into three groups: 1) 8 normal pregnant women, 2) 8 cases with clinical evidence of severe PIH, and 3) 8 normotensive non-pregnant women.The normal pregnant group (232 ñ 172 pg mg-1 2h-1) and the non-pregnant control group (237 ñ 146 pg mg-1 2h-1 0 showed similar PGI2 production in the omentum arteries, whereas the PIH group showed lower PGI2 generation (P<0.05) than the normal patients both in the umbilical (697 ñ 377 vs 1528 ñ 291 pg mg-1 2h-1) and omentum (132 ñ 73 vs 232 ñ 172 pg mg-1 2h-1) arteries. PGI2 production was 6.8 times lower in the omentum arteries than in the umbilical arteries. The data confirm and extend the view of the occurrence of reduced PGI2 production in the maternal-fetal vascular tissues of women with severe PIH.

Thromboxane A2/prostacyclin ratio as a predictor for vascular complication in diabetes mellitus

Vascular complication of diabetes mellitus is a major problem. In a trial to study the platelet function in diabetics we measured, the platelet count and aggregation, both prostacyclin stable metabolite 6 ketoprostacyclin Fl [6KPGFl] and thromboxane stable metabolite [TXB2] to get TXB2/PGI2 ratio. We studied 20 insulin-dependent diabetics and 10 normals as a control. The result showed that no statistically significant difference between the diabetic group and the normal group as regard the platelet count and platelet aggregation both with low [20U] and high [50 U] dose of A.D.P. The level of [6KPGFl.] was significantly lower in diabetics [89.73 pg/0.l ml compared to the normals [228 pg/0.l ml] and the level of TXB2 was significantly higher in diabetics [609.2 pg/0.l ml] compared to the normals [105.3 pg/0.l ml]. Thus, the TXB2/6KPGFl. ratio in diabetics was 50.04 in comparison to 0.56 in the normals. We concluded that the loss of balance between the aggregator thromboxane A2 and the inhibitory prostacyclin may contribute to the evolution of vascular complication in diabetics

Síntesis de éteres cíclicos prostanoides con actividad hematológica o inmunológica / Synthesis of prostandid cyclic ethers with hematological or inmunological activity

En este trabajo se presenta la síntesis de algunos éteres cíclicos prostanoides, análogos de la prostaciclina obtenidos partiendo del intermediario PGA2 (extraído del coral blando Plexura homomalla, recolectado en la costa note de Venezuela); conjuntamente con algunas pruebas farmacológicas preminares en el área de inmunología o hematología