Simultaneous maternal indirect blood pressure measurements, electronic fetal heart rate monitoring, and ultrasonographic biophysical profile testing were used to assess maternal-fetal homeostasis in gravid ewes during gestational days 127 to 134 (term 146), during a 72-hour fast, and during treatment with thromboxane synthetase inhibitors CGS13080 and CGS12970. Seventy-five percent of the ewes (12 of 16) developed clinical signs of ovine pregnancy-induced hypertension, including maternal hypertension and fetal depression. In three untreated hypertensive ewes, pregnancy was terminated by spontaneous premature delivery, and one maternal death occurred after an eclamptic seizure. All nine ewes treated with one of the two thromboxane synthetase inhibitors responded to therapy with decreases in blood pressure and resolution of fetal depression. These nine ewes completed gestation, and were delivered at term. These data indicate that therapy with thromboxane synthetase inhibitors in this animal model of preeclampsia results in profoundly beneficial effects and suggest that further studies of thromboxane synthetase inhibitors are warranted in preeclampsia.

L’apoptose est un processus dont l’importance physiologique et pathophysiologique est de mieux en mieux appréciée. Si plusieurs mécanismes expliquant son initiation et son exécution ont été décrits, les détails de sa régulation fine restent à être précisés. Par ces travaux, nous démontrons une interaction directe entre la protéine pro-apoptotique Siva1 et la queue C-terminale de plusieurs récepteurs couplés aux protéines G, incluant TP, IP, PAF, AT?R et CHRM3. Pour TP, nous prouvons que la stimulation du récepteur par le U46619 entraîne une translocation et une accumulation cytoplasmique de Sival, ainsi qu’une modulation de ses interactions avec Mdm2, XIAP et TRAF2, résultant en une induction de l’apoptose. Nous rapportons également que l’expression de Siva1 potentialise l’ubiquitinylation de TP en réponse à une stimulation et que cette ubiquitinylation n’affecte ni la dégradation, ni l’internalisation du récepteur. Nous démontrons par ailleurs que la stimulation de TP diminue l’expression totale d’i?B?, l’inhibiteur principal de la voie NF?B et que cet effet corrèle avec le niveau d’expression de Siva1. En démontrant l’existence d’un complexe entre TP et TRAF2 suite à une stimulation réceptorielle, nous proposons que la modulation NF?B par TP pourrait résulter d’une signalisation dépendant de l’ubiquitine et analogue à celle des TNFR. D’autre part, nous présentons une interaction entre Siva1 et l’arrestine et apportons des données suggérant que l’expression de Siva1 pourrait moduler l’activation des MAPK. Nous proposons finalement un modèle réconciliant les fonctions anti- et pro-apoptotiques de TP et dans lequel le phénotype final d’une stimulation dépendrait de l’expression relative de Siva1. Les corolaires de ce modèle pourraient possiblement bonifier la prise en charge d’incidents ischémiques comme l’infarctus du myocarde ou l’accident vasculaire cérébral, et améliorer le traitement du cancer par une diminution de la toxicité d’agents chimiothérapeutiques et l’amélioration de la sensibilité tumorale.[symboles non conformes]

Metastasis is the major cause of cancer related mortality, due to a poor understanding of the metastatic process and a subsequent lack of effective anti-metastatic therapies. Evidence from experimental studies and clinical trials has shown that aspirin reduces the incidence of distant metastases. It is well established that aspirin inhibits cyclooxygenase (COX)-1 and COX-2, triggering anti-thrombotic and anti-inflammatory effects, respectively. However, the mechanisms underlying the anti-metastatic effect of aspirin are still largely unknown. By using an experimental model of pulmonary metastasis, we have found that the anti-metastatic effect of aspirin is associated with the inhibition of COX-1. In support of this, metastasis establishment was impaired in COX-1 deficient mice, suggesting a pivotal role of this isoform in the metastatic process. Looking in more detail into the metastatic cascade, we found that COX-1 contributes to the intravascular phase of metastasis and promotes the early persistence of tumour cells in the lung vasculature. In particular, COX-1 inhibition decreased the interaction of platelets with tumour cells and was associated with the reduction of endothelial activation, of tumour cell adhesion to the endothelium, of recruitment of metastasis-promoting monocytes/macrophages and of transendothelial migration. We have identified platelet-derived thromboxane A₂ (TXA₂) as the main product of COX-1 responsible for its permissive effect on metastasis. Indeed, TXA₂ delivered to mice in combination with aspirin was able to abrogate the anti-metastatic effect of aspirin. Taken together, our data suggest that the inhibition of COX-1:TXA₂ axis by aspirin is sufficient to exert an anti-metastatic effect. In particular, the inhibition of platelet-derived TXA₂ seems to affect multiple early steps of the haematogenous transit of tumour cells. In this perspective, TXA₂ might represent a more selective therapeutic target for the prevention of metastasis.

Liu, Yi. / Thesis Ph.D. Chinese University of Hong Kong 2015. / Includes bibliographical references (leaves 154-175). / Abstracts also in Chinese. / Title from PDF title page (viewed on 25, October, 2016).

Vascular reactivity to vasopressin and phenylephrine is potentiated by constrictor prostanoids (CP) in normotensive female (F) but not male (M) rat aorta and CP function is estrogen-dependent. This study investigated the effects of estrogen on CP function and arterial blood pressure (MAP) during development of aortic coarctation-induced hypertension (HT). M and F rats, (15-18 wks.) in four groups: normotensive (NT), hypertensive (HT), ovariectomized (OVX), and OVX estrogen-replaced (OE), underwent abdominal aortic coarctation or sham surgery (NT). At 14 days, SQ 29,548 (SQ, Thromboxane A2 (TXA2) receptor antagonist) was given i.v. to the groups. In another experiment, rats received Ridogrel (TXA2 receptor antagonist+TXA2 synthase (TXS) inhibitor) or vehicle (methyl cellulose) daily, for 14 days. Thoracic aortae were analyzed for morphology, incubated in Kreb’s Henseleit Buffer (KHB) ± angiotensin II (ANG II), or underwent continuous pulsatile flow and pressure experiments (PFP) with KHB ± ANG II. Perfusate was analyzed for thromboxane B2 (TXB2) and prostaglandin F1α (PGF1α). RT-PCR and immunohistochemistry were performed for TXS. MAP was higher in F-HT than in M-HT after 14 days. SQ infusion reduced MAP substantially more in F-HT and OE-HT than in others. Ridogrel prevented increases in MAP in F/OE-HT rats, but not M/OVX-HT. Basal release of TXB2 and PGF1α increased to a greater extent in F-HT than in M-HT relative to their controls. ANG II-stimulated TXB2 and PGF1α release increased to a greater extent in F-HT than in M-HT. With or without ANG II, TXB2 production in HT during PFP increased with estrogen. PGF1α increased during PFP with estrogen, however not with ANG II. Pressurization resulted in less diameter change in F and OE-HT than in OVX-HT. Elastin increased with HT (inhibited by Ridogrel) in all but M. Collagen increased in HT with estrogen (inhibited by Ridogrel). Neither OVX-HT nor Ridogrel had any effect on morphology. Estrogen increased TXS with HT. Estrogen enhanced vascular CP and MAP in F-HT by increased expression of TXS and collagen density in the vasculature indicating that in aortic coarctation-induced HT, CP are upregulated by estrogen. Specific forms of HT in human beings may involve estrogen-induced vascular CP upregulation.

Vascular reactivity to vasopressin and phenylephrine is potentiated by constrictor prostanoids (CP) in normotensive female (F) but not male (M) rat aorta and CP function is estrogen-dependent. This study investigated the effects of estrogen on CP function and arterial blood pressure (MAP) during development of aortic coarctation-induced hypertension (HT). M and F rats, (15-18 wks.) in four groups: normotensive (NT), hypertensive (HT), ovariectomized (OVX), and OVX estrogen-replaced (OE), underwent abdominal aortic coarctation or sham surgery (NT). At 14 days, SQ 29,548 (SQ, Thromboxane A2 (TXA2) receptor antagonist) was given i.v. to the groups. In another experiment, rats received Ridogrel (TXA2 receptor antagonist+TXA2 synthase (TXS) inhibitor) or vehicle (methyl cellulose) daily, for 14 days. Thoracic aortae were analyzed for morphology, incubated in Kreb’s Henseleit Buffer (KHB) ± angiotensin II (ANG II), or underwent continuous pulsatile flow and pressure experiments (PFP) with KHB ± ANG II. Perfusate was analyzed for thromboxane B2 (TXB2) and prostaglandin F1α (PGF1α). RT-PCR and immunohistochemistry were performed for TXS. MAP was higher in F-HT than in M-HT after 14 days. SQ infusion reduced MAP substantially more in F-HT and OE-HT than in others. Ridogrel prevented increases in MAP in F/OE-HT rats, but not M/OVX-HT. Basal release of TXB2 and PGF1α increased to a greater extent in F-HT than in M-HT relative to their controls. ANG II-stimulated TXB2 and PGF1α release increased to a greater extent in F-HT than in M-HT. With or without ANG II, TXB2 production in HT during PFP increased with estrogen. PGF1α increased during PFP with estrogen, however not with ANG II. Pressurization resulted in less diameter change in F and OE-HT than in OVX-HT. Elastin increased with HT (inhibited by Ridogrel) in all but M. Collagen increased in HT with estrogen (inhibited by Ridogrel). Neither OVX-HT nor Ridogrel had any effect on morphology. Estrogen increased TXS with HT. Estrogen enhanced vascular CP and MAP in F-HT by increased expression of TXS and collagen density in the vasculature indicating that in aortic coarctation-induced HT, CP are upregulated by estrogen. Specific forms of HT in human beings may involve estrogen-induced vascular CP upregulation.

Introduction: The recurrence of the cerebral ischemic stroke after a history of TIA or ischemic stroke is 3-4% per year. One way of reducing the risk of reccurence is using antiplatelet therapy. The aim of our study was to investigate the effect of aspirin. Even though, newer antiplatelet drugs were developed, their risk/benefit profile has not been proved to be better than aspirin. Reasons for using aspirin in secondary prevention are: the longest experience, clearly proven effect in many studies and low price. On the other hand, aspirin prevents only 25% of strokes, thus there is wide space for searching for causes of failed therapy and alternative therapeutic ways. Noncompliance of aspirin use and embolic events are usually indicated as the most common causes of an ineffective therapy. The goal of our study was to find the antiplatelet therapy effectivity in patients with history of stroke treated with aspirin in daily dose of 100mg. We assured 100% compliance among these patients and as much as possible minimalized a likelihood of embolic causes of strokes. What is more, we tried to find out whether an insuffient suppression of 11-dehydrotromboxane B2 correlates with comorbidities, other used medication or laboratory parameters. Furthermore, whether by administrating an increased dose of...

Introduction: The recurrence of the cerebral ischemic stroke after a history of TIA or ischemic stroke is 3-4% per year. One way of reducing the risk of reccurence is using antiplatelet therapy. The aim of our study was to investigate the effect of aspirin. Even though, newer antiplatelet drugs were developed, their risk/benefit profile has not been proved to be better than aspirin. Reasons for using aspirin in secondary prevention are: the longest experience, clearly proven effect in many studies and low price. On the other hand, aspirin prevents only 25% of strokes, thus there is wide space for searching for causes of failed therapy and alternative therapeutic ways. Noncompliance of aspirin use and embolic events are usually indicated as the most common causes of an ineffective therapy. The goal of our study was to find the antiplatelet therapy effectivity in patients with history of stroke treated with aspirin in daily dose of 100mg. We assured 100% compliance among these patients and as much as possible minimalized a likelihood of embolic causes of strokes. What is more, we tried to find out whether an insuffient suppression of 11-dehydrotromboxane B2 correlates with comorbidities, other used medication or laboratory parameters. Furthermore, whether by administrating an increased dose of...

Die Hypothese, dass das AP Clozapin, ebenso wie dessen Metabolit NDMC die Produktion von TxA2 beeinfluss könnten, stellten wir nach ausführlicher Literaturrecherche auf. Letztere zeigte, dass bereits beim ersten AP CPZ eine reduzierende Wirkung auf die TxA2-Produktion nachgewiesen werden konnte. TxA2 und die Aktivierung seines Rezeptors modulieren Vasokonstriktion und Thrombozytenaggregation. Weiterhin nehmen sie Einfluss auf dopaminerge und serotonerge Signalwege. In der Pathophysiologie der Schizophrenie spielen eben diese eine bedeutende Rolle und stellen somit Zielstrukturen für APs dar. Um die Konzentration von TxB2, dem Metaboliten des instabilen Moleküls TxA2 in stimulierten und unstimulierten Blutproben 10 gesunder Probandinnen zu messen, verwendeten wir ein Vollblutverfahren. Um signifikante Ergebnisse zu erhalten, stimulierten wir die Proben mit TSST-1 oder dem monoklonalen Antikörper OKT3 (Muromonab-CD3), der gegen das Oberflächenantigen CD3 gerichtet ist, kombiniert mit dem monoklonalen Antikörper 5C3, der mit dem Protein CD40 interagiert und es stimuliert. Weiterhin versetzten wir das Blut mit den APs CPZ, Clozapin oder NDMC in einer von vier verschiedenen Konzentrationen. Außerdem wurden die Thromboxanspiegel im Blut ohne Zusatz von APs unter verschiedenen Stimulationskonditionen gemessen. Durch den Zusatz von Clozapin in den verschiedenen Konzentrationen kam es zu einer signifikanten (p<0.05) Verringerung der TxB2-Produktion in den mit TSST-1 und ebenso in den mit OKT3/5C3 versetzen Proben, was wir im Rahmen unserer Studie feststellen konnten. Weiterhin konnten wir zeigen, dass CPZ in sehr niedriger Konzentration die TxB2-Spiegel im unstimulierten und im mit TSST-1 stimulierten Blut reduziert. Daraus lässt sich schlussfolgern, dass Clozapin, NDMC und CPZ auch über eine Modulation der TxA2- und TxB2-Produktion das Neurotransmittersystem beeinflussen könnten. Auch typische Nebenwirkungen der AP, wie zum Beispiel die orthostatische Hypotension, könnten aus den Veränderungen der TxA2- und TxB2-Konzentrationen resultieren.

Die Hypothese, dass das AP Clozapin, ebenso wie dessen Metabolit NDMC die Produktion von TxA2 beeinfluss könnten, stellten wir nach ausführlicher Literaturrecherche auf. Letztere zeigte, dass bereits beim ersten AP CPZ eine reduzierende Wirkung auf die TxA2-Produktion nachgewiesen werden konnte. TxA2 und die Aktivierung seines Rezeptors modulieren Vasokonstriktion und Thrombozytenaggregation. Weiterhin nehmen sie Einfluss auf dopaminerge und serotonerge Signalwege. In der Pathophysiologie der Schizophrenie spielen eben diese eine bedeutende Rolle und stellen somit Zielstrukturen für APs dar. Um die Konzentration von TxB2, dem Metaboliten des instabilen Moleküls TxA2 in stimulierten und unstimulierten Blutproben 10 gesunder Probandinnen zu messen, verwendeten wir ein Vollblutverfahren. Um signifikante Ergebnisse zu erhalten, stimulierten wir die Proben mit TSST-1 oder dem monoklonalen Antikörper OKT3 (Muromonab-CD3), der gegen das Oberflächenantigen CD3 gerichtet ist, kombiniert mit dem monoklonalen Antikörper 5C3, der mit dem Protein CD40 interagiert und es stimuliert. Weiterhin versetzten wir das Blut mit den APs CPZ, Clozapin oder NDMC in einer von vier verschiedenen Konzentrationen. Außerdem wurden die Thromboxanspiegel im Blut ohne Zusatz von APs unter verschiedenen Stimulationskonditionen gemessen. Durch den Zusatz von Clozapin in den verschiedenen Konzentrationen kam es zu einer signifikanten (p<0.05) Verringerung der TxB2-Produktion in den mit TSST-1 und ebenso in den mit OKT3/5C3 versetzen Proben, was wir im Rahmen unserer Studie feststellen konnten. Weiterhin konnten wir zeigen, dass CPZ in sehr niedriger Konzentration die TxB2-Spiegel im unstimulierten und im mit TSST-1 stimulierten Blut reduziert. Daraus lässt sich schlussfolgern, dass Clozapin, NDMC und CPZ auch über eine Modulation der TxA2- und TxB2-Produktion das Neurotransmittersystem beeinflussen könnten. Auch typische Nebenwirkungen der AP, wie zum Beispiel die orthostatische Hypotension, könnten aus den Veränderungen der TxA2- und TxB2-Konzentrationen resultieren.