Thromboxane B2, 6-keto-PGF1 alpha, PGE2, PGF2 alpha, and PGA1 plasma levels in arteriosclerosis obliterans: relationship to clinical manifestations, risk factors, and arterial pathoanatomy

Effect of specialized pro-resolving lipid mediators in the regulation of vascular tone and inflammation in human saphenous vein

Specialized pro-resolving lipid mediators (SPMs), derived from polyunsaturated fatty acids are important mediators in the resolution of inflammation. Recent studies have focused on the effects of SPMs in cardiovascular health and diseases. However, little is known about the effect SPMs on human vascular tone. Therefore, in this study it is aimed to investigate the effect of various SPMs including resolvin D- and E-series, maresin-1 (MaR1) and lipoxin-A4 (LxA4) on the vascular tone of human isolated saphenous vein (SV) preparations under inflammatory conditions. In addition, we aimed to evaluate the effects of SPMs on the release of pro-inflammatory mediators, monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF- α) from human SV. Pretreatment of isolated of human SV with resolvin E1 (RvE1), resolvin D1 (RvD1) and MaR1 (100 nM, 18 h) significantly reduced the contractile responses to thromboxane A2 mimetic, U46619 whereas pretreatment with LxA4 and RvD2 (100 nM, 18 h) had no significant effect on the vascular tone of SV. Moreover, RvE1, RvD1 and MaR1 but not LxA4 and RvD2 (100 nM, 18 h) pretreatment diminished the release of MCP-1 and TNF-α from SV. In conclusion, our findings suggest that pre-treatment with RvE1, RvD1, and MaR1 could have potential benefits in decreasing graft vasospasm and vascular inflammation in SV.

Sarcoelegans A-H, eight undescribed cembranes with anti-inflammatory and anti-thrombotic activities from the South China Sea soft coral Sarcophyton elegans

Chemical investigation of the South China Sea soft coral Sarcophyton elegans has led to the isolation of eight undescribed cembranes, namely sarcoelegans A-H. Their structures and absolute configurations were unambiguously established by extensive analyses of spectroscopic data, X-ray diffraction, QM-NMR, and TDDFT-ECD calculations. Sarcoelegan A is composed of the rare tricyclo [11.2.1.0] hexadecane carbon framework which is the third compound of this scaffold. Sarcoelegan B and sarcoelegan C possess an unusual seven-membered ether ring, and (±)-sarcoelegan D has a seven-membered ring with the rare peroxo bridge. In addition, sarcoelegan A, (±)-sarcoelegan D, sarcoelegan E, (+)-sarcoelegan F, and (+)-sarcoelegan H exhibited anti-inflammatory activity in zebrafish and sarcoelegan C exhibited anti-thrombotic activity in zebrafish.

Preventive effect and mechanism of Tibetan tea extract on thrombosis in arachidonic acid-induced zebrafish determined via RNA-seq transcriptome profiles

Thrombosis is a key pathological event in cardiovascular diseases and is also the most important targeting process for their clinical management. In this study, arachidonic acid (AA) was used to induce thrombus formation in zebrafish larvae. Blood flow, red blood cell (RBCs) aggregation and cellular oxidative stress were measured to evaluate the antithrombotic effect of Tibetan tea (TT). Meanwhile, the potential molecular mechanism was further explored by transcriptome sequencing (RNA-seq). The results indicated that TT could significantly restore heart RBCs intensity of thrombotic zebrafish, whilst decreasing RBCs accumulation in the caudal vein. The transcriptome analysis revealed that the preventive effect of TT on thrombosis could be mostly attributed to changes in lipid metabolism related signaling pathways, such as fatty acid metabolism, glycerollipid metabolism, ECM-receptor interaction and steroid biosynthesis signaling pathway. This study demonstrated that Tibetan tea could alleviate thrombosis by reducing oxidative stress levels and regulating lipid metabolism.

Serum Metabolomic Analysis of Coronary Heart Disease Patients with Stable Angina Pectoris Subtyped by Traditional Chinese Medicine Diagnostics Reveals Biomarkers Relevant to Personalized Treatments

To improve the treatment of patients with coronary heart disease (CHD), personalized treatments based on potential biomarkers could make a difference. To investigate if such potential biomarkers could be found for CHD inhomogeneous, we combined traditional Chinese medicine based diagnosis with untargeted and targeted metabolomics analyses. Shi and Xu patient subtype groups of CHD with angina pectoris were identified. Different metabolites including lipids, fatty acids and amino acids were further analyzed with targeted metabolomics and mapped to disease-related pathways. The long-chain unsaturated lipids ceramides metabolism, bile acid metabolism were differentially affected in the Xu subtype groups. While, Shi-subtype patients seemed to show inflammation, anomalous levels of bioactive phospholipids and antioxidant molecules. Furthermore, variations in the endothelial damage response and energy metabolism found based on ELISA analysis are the key divergence points between different CHD subtypes. The results showed Xu subtype patients might benefit from long-chain unsaturated lipids ceramides as therapeutic targets. Shi subtype patients might benefit more from levels of polyunsaturated fatty acid consumption and treatments that help in restoring energy balance. Metabolic differences can be essential for treatment protocols. Thus, patient group specific differences can serve as important information to refine current treatment approaches in a personalized manner.

Discovery and identification of antithrombotic chemical markers in Gardenia Fructus by herbal metabolomics and zebrafish model

ETHNOPHARMACOLOGICAL RELEVANCE

Gardenia Fructus (GF), a traditional Chinese medicine for clearing heat and purging fire, has been reported to use to treat thrombotic related diseases, but the antithrombotic components are not clear.

AIM OF THE STUDY

To develop efficient research methods for discovering some representative antithrombotic compounds of GF.

MATERIALS AND METHODS

AB line zebrafish induced by arachidonic acid (AA) was used as a fast and trace-sample-required valuation model for antithrombptic effect of GF samples. Among nine samples of GF from different production areas, two samples with the largest difference in bioactivity were selected for downstream analysis. High-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF/MS) was applied to detect compounds in the GF samples. And herbal metabolomics and grey correlation analysis (GCA) were used to identify crucial compounds with potential antithrombotic activity. Then the bioactivity of those important compounds was verified on the zebrafish model. Network pharmacology was used to explore the protein targets and signaling pathways of these compounds.

RESULTS

Among the GF samples, S1 (Huoshan City, Anhui Province), and S6 (Jichun City, Hubei Province), significantly differed in thrombus inhibiting bioactivity. HPLC-Q-TOF/MS identified a total of 614 compounds in each GF sample. 19 compounds were selected as important potential variables from metabolomics data by orthogonal partial least squares discriminant analysis (OPLS-DA). And 10 compounds among them were further found to be positively correlated with the antithrombotic bioactivity of GF by GCA. Finally, 3 compounds in them, geniposide, citric acid, and quinic acid, were confirmed as representative antithrombotic chemical markers of GF. Using network pharmacology analysis, some key protein targets, such as proto-oncogene tyrosine-protein kinase Src (SRC) and cyclin-dependent kinase 2 (CDK2), and some signaling pathways were found to supply powerful evidence about antithrombotic mechanisms of three compounds and GF.

CONCLUSIONS

This research have succeeded to discover and identify three representative antithrombotic compounds of GF using an efficient integrated research strategy we established, an Omics Discriminant-Grey Correlation-Biological Activity strategy. The antithrombotic chemical makers we found could also contribute to provided more accurate index components for comprehensive quality control of GF.

Predictors of thromboxane levels in patients with non-ST-elevation acute coronary syndromes on chronic aspirin therapy

High levels of thromboxane A2 (TxA2), a key mediator of platelet activation and aggregation, are associated with an increased risk of cardiovascular events. We aimed at assessing the predictors of higher plasma levels of TxB2, the stable metabolite of TxA2, in consecutive patients presenting with non-ST-elevation acute coronary syndrome (NSTE-ACS) on previous aspirin (ASA) treatment undergoing coronary angiography. Ninety-eight consecutive patients (age 61 ± 11, 75% males) with NSTE-ACS, on previous chronic ASA treatment, were prospectively enrolled in this study. Coronary disease extent was assessed by angiography according to the Bogaty score. In all patients, admission plasma levels of TxB2 (pg/ml) were measured by enzyme-linked immunosorbent assay, and patients showing TxB2 levels in the fourth quartile were compared to patients showing TxB2 levels in the lower quartiles. Multivariable logistic regression analysis showed that platelet count (odds ratio [OR] 1.18, 95% confidence interval [CI] 1.02–1.63, p=0.04), multivessel coronary disease (OR 1.37, 95% CI 1.13–3.67, p=0.03), and coronary atherosclerosis extent index (OR 1.91, 95% CI 1.45–6.79, p=0.001) were independent predictors of TxB2 level upper quartile. Of note, C-reactive protein serum levels were similar in patients with TxB2 levels in the upper quartile as compared to those in the lower quartiles (p=0.49). In conclusion, NSTE-ACS patients with severe coronary atherosclerosis may have incomplete suppression of TxA2 production despite chronic ASA therapy. This finding suggests that additional efforts should be made to lower TxA2 levels in patients with widespread coronary artery disease.

Identification of a Quality Marker (Q-Marker) of Danhong Injection by the Zebrafish Thrombosis Model

Quality-marker (Q-marker) is an emerging concept to ensure the quality and batch-to-batch consistency of Chinese medicine (CM). However, significant difficulties remain in the identification of Q-markers due to the unclear relationship between complex chemical compositions and the pharmacological efficacy of CM. In the present study, we proposed a novel strategy to identify the potential Q-marker of danhong injection (DHI) by an in vivo zebrafish thrombosis model. The anti-thrombotic effects of DHI and its major constituents were evaluated by the zebrafish model of arachidonic acid (AA)-induced thrombosis. The results indicated that DHI can attenuate tail venous thrombus and recover the decrease of heart red blood cell (RBC) intensity in a dose-dependent manner. The result that DHI prevented the formulation of thrombosis in zebrafish was also validated in the zebrafish thrombosis model with green fluorescence protein (GFP)-labeled hemoglobin. The major components of DHI, namely danshen (DS) and honghua (HH), as well as the major chemical constituents of DHI, also exerted anti-thrombotic effects, among which rosmarinic acid (RA) and p-coumaric acid (pCA) showed moderate anti-thrombotic effects. This is the first time that pCA from HH has been found as an active compound exerting an anti-thrombotic effect in a dose-dependent manner, whose IC₅₀ value is approximately 147 μg/mL. By analyzing 10 batches of normal DHI samples and five abnormal samples by high-performance liquid chromatography (HPLC), we found the contents of pCA and RA can be positively correlated to the anti-thrombotic effect of DHI, suggesting that pCA and RA could be potential Q-markers of DHI to ensure batch-to-batch consistency. Our findings illustrated that discovering major active compounds from CM by in vivo pharmacological models can be a useful approach to identifying Q-markers of CM, and in vivo pharmacological models can be a potential tool to evaluate batch-to-batch consistency of CMs.

Prostanoids in the pathophysiology of human coronary artery

Coronary artery disease is one of the leading causes of death in wordwide. There is growing evidence that prostanoids are involved in the physiology and pathophysiology of the human coronary artery by controlling vascular tone, remodelling of the vascular wall or angiogenesis. In this review, the production of prostanoids and the expression of prostanoid receptors in human coronary artery in health or disease are described. In addition, the interactions between sex hormones and prostanoids, their participations in the development of coronary artery diseases have been addressed. Globally, most of the studies performed in human coronary artery preparations have shown that prostacyclin (PGI₂) has beneficial effects by inducing vasodilatation and promoting angiogenesis while reverse effects are confirmed by thromboxane A₂ (TxA₂). More studies are needed to determine the roles of the other prostanoids (PGE₂, PGD₂ and PGF_2α) in vascular functions of the human coronary artery. Finally, in addition to the in vitro data about the human coronary artery, myocardial infarction induced by cyclooxygenase-2 (COX-2) inhibitor and the protective effects of aspirin after coronary artery bypass surgery suggest that prostanoids are key mediators in coronary homeostasis.

Overexpression of COX-2, Prostaglandin E synthase-1 and prostaglandin E receptors in blood mononuclear cells and plaque of patients with carotid atherosclerosis: regulation by nuclear factor-kappaB

BACKGROUND AND OBJECTIVE

Prostaglandin E2 (PGE(2), a product of the cyclooxygenase 2 (COX-2) and membrane-associated Prostaglandin E Synthase (mPGES-1) pathway, has been implicated in the instability of atherosclerotic plaques. We have studied COX-2, mPGES-1 and PGE2 receptors (EPs) expression in peripheral blood mononuclear cells (PBMC) and atherosclerotic plaques of 29 patients with carotid stenosis as well as the effect of different nuclear factor-kappaB (NF-kappaB) inhibitors on COX-2, mPGES-1 and EPs expression in cultured monocytic cells (THP-1).

METHODS

COX-2, mPGES-1 and EP expression was analyzed by RT-PCR (PBMC), immunohistochemistry (plaques) and Western blot (THP-1). PGE2 levels were determined by ELISA (plasma and cell supernatants).

RESULTS

In relation to healthy controls, COX-2, mPGES-1 and EP-3/EP-4 mRNA expression was increased in PBMC from patients. In the inflammatory region of atherosclerotic plaques, an increase of COX-2, mPGES-1 and EPs expression was also observed. Activated NF-kappaB and COX-2, mPGES-1 and EPs proteins were colocalized in the plaque's cells. In cytokine-treated cultured THP-1, the NF-kappaB inhibitors parthenolide, Bay 11-7082 and PDTC reduced COX-2, mPGES-1 and EP-1/EP-3/EP-4 expression as well as PGE2 levels. By employing specific agonists and antagonists, we noted that the cytokine- and PGE2-induced metalloproteinase 9 (MMP-9) expression and activity occurs through EP-1/EP-3/EP-4, an effect downregulated by NF-kappaB inhibitors.

CONCLUSIONS

Patients with carotid atherosclerosis depict an overexpression of COX-2, mPGES-1 and EPs simultaneously in the PBMC as well as in the vulnerable region of plaques. The studies in cultured monocytic cells suggest that NF-kappaB inhibitors and/or EPs antagonists could represent a novel therapeutic approach to the treatment of plaque instability and rupture.

Effect of acute thromboxane A2 inhibition on the renal hemodynamics in a spontaneously non-insulin-dependent diabetic rat, Otsuka Long-Evans Tokushima Fatty rat

Thromboxane (TX) A2 plays important roles on renal injuries in streptozotocin (STZ)-induced diabetic rats, whereas its role on the renal injuries in non-insulin-dependent diabetic (NIDDM) rats remains unknown. We evaluated the effects of an intravenous infusion of TXA2 synthetase inhibitor (OKY-046, 6 mg/kg/h) on the clearances on inulin and para-aminohippurate (Cin, C(PAH)) in a spontaneously NIDDM rats, Otsuka Long-Evans Tokushima Fatty (OLETF) rats (n = 8), and Long-Evans Tokushima Otsuka (LETO) rats (n = 7), served as control rats, at the age of 40-44 weeks. OLETF rats showed obesity, moderate hyperglycemia, and hyperinsulinemia. Urinary excretion of TXB2 was slightly higher and the ratio of TXB2 to 6-keto prostaglandin F1alpha (6-kPG) was significantly higher in OLETF rats (TXB2/6-kPG: 0.22 +/- 0.04 versus 0.12 +/- 0.02, P < 0.05). Both Cin and C(PAH) were significantly higher in OLETF rats than in LETO rats (Cin: 1.1 +/- 0.1 versus 0.7 +/- 0.1 mL/min/100 g BW, C(PAH): 3.1 +/- 0.2 versus 2.3 +/- 0.3 mL/min/100gBW, P < 0.01). OKY-046 did not restore Cin and C(PAH) in OLETF rats although it significantly decreased urinary excretion of TXB2, and thus ameliorated TXB2/6-kPG in OLETF rats. These data suggested that TXA2 was not involved in the renal hyperfiltration in OLETF rats at the age of 40-44 weeks, and that TXA2 might contribute to renal injuries in OLETF rats through mechanisms other than hemodynamic injury.

ACE inhibition with perindopril and atherogenesis-induced structural and functional changes in minipig arteries

The effects of angiotensin-converting-enzyme (ACE) inhibition on atherosclerosis-induced changes in arterial function are unknown, as well as whether they are coupled to improvements of structural alterations in the arterial wall. An atherogenic (A) diet and the ACE inhibitor perindopril (P) were given concomitantly for 4 months to seven adult Pitman-Moore minipigs (7 months of age; A+P animals), which were compared with seven A and seven control (C) animals. Perindopril, at a daily dose of 4 mg PO that is commonly used in the clinical setting, induced a continuous 70% inhibition of serum ACE activity. At the end of the study, the atherosclerosis-induced impairment of arterial flow was investigated via the hemodynamics and vascular rheology of hindlimb arteries in non-barbiturate-anesthetized pigs. Structural alterations were evaluated from the histopathology of lesions in the arterial tree (abdominal aorta, left interventricular coronary artery [LIVCA], and brachiocephalic trunk [BCT]), with particular attention given to the analysis of the structure and composition of aortic elastic fibers. Atherosclerosis impaired the function of both capacitance and resistance arteries. Blood pressure (BP) rose significantly because of increased hindlimb peripheral resistance (HPR) and aortic input impedance (Zc), although blood flow was not affected. Altered aortic stress and elastic responses revealed that the stiffness of the aorta was markedly increased because of increased wall tension and reduced viscoelasticity, the viscous component being blunted in the arterial wall. Perindopril significantly opposed these alterations by reducing BP, HPR, and Zc and by returning parietal stiffness values to C values by increasing aortic compliance. ACE inhibition prevented the alteration of both stress and elastic responses. Major fibroproliferative fatty lesions were observed in the aorta and LIVCA, while moderate fibrosclerotic lesions were found in the BCT. Computerized densitometric analysis of orcein-stained elastin showed that elastic laminae fragmentation was prominent in the abdominal aorta, less in the LIVCA, and moderate in the BCT. Furthermore, the elastin content was reduced in the atherosclerotic aorta, although this loss of elastin was not associated with changes in the biochemical nature of alkali-insoluble elastin. Perindopril significantly prevented the development of atherosclerosis in the abdominal aorta, LIVCA, and BCT by decreasing the cross-sectional area of lesions as well as the number of lipid-laden cells in the abdominal aorta and LIVCA. In the abdominal aorta, ACE inhibition significantly prevented the alteration of elastic laminae by specifically preventing elastolytic fragmentation of dense elastic laminae, but it didn ot modify elastin content.(ABSTRACT TRUNCATED AT 400 WORDS)

Risk factors for atherosclerotic aortoiliac occlusive disease

Notwithstanding the difficulties in analysis because of the small number of studies available, patients with aortoiliac atherosclerosis, irrespective of their sex, have a particular "risk profile" that includes tobacco use, young age, diabetes (rare), frequent hypercholesterolemia, and limited atheroma. It must be remembered, however, that most studies have not dealt with the specific risk factors of lower limb arterial disease and the location of disease in the aortoiliac vessels. It is possible that the classical analysis of the vascular risk factors has overlooked one or more major factors such as hyperhomocysteinemia. This underscores the necessity to conduct further prospective studies specifically focused on the various aspects of lower limb and aortoiliac arterial disease in particular.

Effects of angiotensin-converting enzyme inhibition with perindopril on hemodynamics, arterial structure, and wall rheology in the hindquarters of atherosclerotic mini-pigs

The effects of ACE inhibition with perindopril on the atherosclerosis-induced impairment of arterial flow were investigated via histopathologic studies, hemodynamics, and vascular rheology of hindlimb arteries in 7 adult Pitman-Moore mini-pigs (7 months of age) fed for 4 months with an atherogenic diet and perindopril (at the daily oral dose of 4 mg, which induced a continuous 70% inhibition of serum ACE activity), versus 7 atherogenic and 7 control animals. Major fibroproliferative fatty lesions with medial intimalization were observed in the abdominal aorta. Atherosclerosis impaired the function of both capacitance and resistance hindlimb arteries. In atherogenic mini-pigs, blood pressure (BP) increased significantly due to increased hindlimb peripheral resistance (HPR) and aortic input impedance, although aortic blood flow was not affected. Altered aortic wall rheology revealed that the stiffness of the aorta was markedly increased due to increased wall tension and reduced viscoelasticity, the viscous component being reduced in the arterial wall. Perindopril significantly opposed these alterations by reducing BP, HPR and input impedance and by returning parietal stiffness to control values by increasing aortic compliance. Angiotensin converting enzyme (ACE) inhibition significantly prevented the development of atherosclerosis in the abdominal aorta by decreasing the cross-sectional area of lesions and the presence of lipid-laden cells, as well as by preventing alteration and fragmentation of elastic laminae. In conclusion, ACE inhibition with perindopril showed a significant preventive action on atherosclerosis-induced deleterious effects on vascular wall function and structure in mini-pig arteries.

Comparison of the effects of diets rich in stearic acid versus myristic acid and lauric acid on platelet fatty acids and excretion of thromboxane A2 and PGI2 metabolites in healthy young men

The present study compared the effects of diets rich in stearic acid (C18:0) versus one high in lauric and myristic acid (C12:0, C14:0) on platelet phospholipid fatty acid levels and concentrations of urinary thromboxane B2 (TXB2) and 6-keto-PGF1 alpha, which are stable metabolites of thromboxane A2 (TXA2) and PGI2 and indicators of cardiovascular hemostasis. A diet high in dairy butter (B) was the source of C12:0 and C14:0; C18:0 was provided by diets high in cocoa butter (CB), milk chocolate (CHOC) or CB+B in a 4:1 ratio (MIX). A randomized, crossover double-blind experimental design was used. Experimental subjects (n = 15) consumed each diet for 26 days, with a 1-month washout period between each experimental period. Urine and blood were collected from each subject at the beginning and end of each dietary period. Urinary TXB2 and 6-keto-PGF1 alpha were analyzed by radioimmunoassay (RIA). There were no effects of diet on the 24-hour excretion of either metabolite or on the ratio of 6-keto-PGF1 alpha/TXB2, even though there were significant changes in the eicosanoid precursor, arachidonic acid (C20:4n-6), in platelet phospholipids. C20:4n-6 levels increased (44.8% +/- 1.0% to 47.1% +/- 1.3%; P < .05) in the phosphatidylethanolamine phospholipid subclass in subjects on the B diet and decreased in the phosphatidylcholine subclass on the CB diet (16.5% +/- 1.0% to 14.2% +/- 1.1%; P < .05) compared with baseline values.(ABSTRACT TRUNCATED AT 250 WORDS)

Implication of thromboxane in the pathogenesis of Kawasaki disease and a suggestion for using novel thromboxane synthetase inhibitors in its treatment

Kawasaki disease, a mucocutaneous lymph node syndrome predominantly prevalent in children, presents with coronary artery aneurysms and thrombocytosis, and investigators have suggested use of anticoagulants in addition to platelet inhibiting drugs. In Kawasaki disease, hypersensitivity reactions due to antigen/antibody complexes (Arthus type III) may damage the vessel wall and induce arteritis, and antigens may be of microbial or viral origin. Since thromboxane has been implicated in the pathogenesis of Kawasaki disease, I suggest use of ginger and carbon dioxide, novel thromboxane synthetase inhibitors. Thromboxane synthetase inhibitors may act as anticoagulants, platelet inhibitors, anti-inflammatory agents, and agents with both antimicrobial and antiviral activity.

Changes in serum lipids in rats treated with PGF2 alpha

Serum lipid concentrations were determined in rats treated with PGF2 alpha, PGE1, and controls. Administration of PGF2 alpha in rats influenced only the HDL lipid composition. HDL-cholesterol decreased while HDL-triglycerides increased. No significant difference was observed in the levels of serum total cholesterol, triglycerides, and phospholipids between animals treated with PGF2 alpha and controls. Reduced concentrations of serum lipid levels and especially of HDL-cholesterol, HDL-triglycerides, and HDL-phospholipids were found in the rats treated with PGE1. These results suggest that PGF2 alpha and PGE1 could modify serum lipid levels influencing lipoprotein metabolism.

Effects of taprostene, a stable prostacyclin analogue, on haemodynamics, platelet function and arachidonate metabolism in healthy volunteers

In order to assess the effect of taprostene on haemodynamics, platelet function and arachidonate metabolism in 4 healthy volunteers an intravenous infusion of 25 ng.kg-1.min-1 was given for 6 h. During the infusion period systolic blood pressure dropped from 130 to 111 mm Hg and diastolic blood pressure from 77 to 69 mm Hg. The heart rate rose from 77 to 84 beats/min. During the taprostene infusion the slope and height of the ADP and collagen induced platelet aggregation curves were significantly inhibited and the sensitivity of platelets to PGI2 and PGE1 was increased. Plasma and serum thromboxane B2, conversion of exogenous radiolabelled arachidonic acid, WU-test, circulating endothelial cell count, concentration of platelet factor 4, beta-thromboglobulin, malondialdehyde and the PGI2-synthesis stimulating plasma factor did not show any clear drug-related alteration. It is concluded that infusion of taprostene 25 ng.kg-1.min-1 caused measurable inhibition of platelet function ex vivo.

The effects of sex hormones on the synthesis of prostacyclin (PGI2) by vascular tissues

The effects of estradiol and testosterone on prostacyclin (PGI2) release (measured as 6-keto-PGF1 alpha) by vascular tissues using rat aortic rings and cultured rabbit aortic smooth muscle cells (SMC) were investigated. Aortic SMC were prepared from either explants of atherosclerotic intima or those of normal media. Aortic rings obtained from male and female rats which had been treated with estradiol resulted in increased PGI2 synthesis. Furthermore, PGI2 synthesis by cultured medial SMC was significantly increased in the presence of estradiol (10(-7), 10(-9) M). An increased tendency in PGI2 synthesis was also observed in intimal SMC. On the other hand, aortic rings obtained from female rats treated with testosterone resulted in a significant decrease in PGI2 synthesis. However, aortic rings from testosterone-treated male rats and cultured medial and intimal SMC treated with testosterone (10(-6), 10(-8) M) for 48 hr did not show any significant changes in PGI2 synthesis. We also found greater PGI2 synthesis by intimal SMC compared with that by medial SMC. These results suggest that estradiol and testosterone may have opposite functions in the development of atherosclerosis, that is, estradiol for anti-atherosclerotic and testosterone for atherogenic, by modulating PGI2 synthesis by vascular tissues.

Prostacyclin, thromboxane A2, and prostaglandin E2 formation in atherosclerotic human carotid artery

Prostaglandin (PG) formation in 16 atherosclerotic human carotid endarterectomy specimens was compared systematically with that of normal carotid artery from seven white pigs and six rhesus monkeys. Prostacyclin (PGI2) formation (picomoles 6-keto-PGF1a/2 min/100 micrograms homogenate protein plus 2 mM glutathione [GSH]) of nonatheromatous intima adjacent proximal (276 +/- 32, mean +/- SEM) or distal (271 +/- 14) to carotid plaque was comparable to that of normal carotid artery from white pig (272 +/- 25, NS) and rhesus monkey (219 +/- 41, NS), and was greater than stenotic intima (156 +/- 17, p less than 0.01), subintimal plaque (168 +/- 14, p less than 0.01), and ulceration (65 +/- 16, p less than 0.01). GSH modulated PGI2 synthesis in all carotid specimens except areas of ulceration (p less than 0.05), but did not restore PGI2 formation in atheromatous fractions to basal level. No detectable arterial thromboxane A2 (TXA2) formation or GSH-dependent PGE2 isomerase activity was observed. The decrement in atherosclerotic carotid artery PGI2 formation was focal (confined to the plaque) and may have been related to loss of effective GSH modulation. These conditions could contribute to a localized imbalance between arterial PGI2 and platelet TXA2 with adverse vascular thromboregulatory consequences.

Plasma thromboxane and prostacyclin metabolite ratio in atherosclerosis and diabetes mellitus

Thromboxane and prostacyclin metabolite determinations (radioimmunoassay) were performed in obliterative atherosclerosis and in diabetes mellitus with microangiopathy. The shift of these metabolites to the thromboxane side could have been documented in both diseases. This phenomenon calls attention to an increased platelet activation and endothelial cell damage. In a third group patients received aspirin (500 mg on alternative days) which caused a marked inhibition of both thromboxane and prostacyclin production, measured this way. The possible role of altered balance of these two prostanoids in atherogenesis and diabetic angiopathy is discussed.

Antithrombogenic endothelial cell defense. Basal characteristics in cultured endothelial cells and modulation by short-term and long-term exposure to isosorbide nitrates

The antithrombogenic endothelial cell defense (ATECD) describes the properties that enable the endothelium to prevent circulating blood platelets from adhering to, or aggregating on, the vascular wall. ATECD was investigated in an experimental model in which bovine passage 0 cultured endothelial cells (EC) were incubated with aggregating platelets and autologous plasma in a computer-operated aggregometer-like device. A maximal platelet aggregation required 150 X 10(-6) M adenosine diphosphate (ADP) to be present in ECs. A 5-minute coincubation for ECs and platelets was found to be adequate in evaluating the maximal ATECD value. By increasing the EC number in the aggregation suspension, platelet aggregation was progressively inhibited through a sigmoid curve (50% inhibition of aggregation required 2 X 10(4) EC). Pharmacologic modulations of ATECD by isosorbide dinitrate (ISDN) + 2-isosorbide mononitrate (2-ISMN) + 5-isosorbide mononitrate (5-ISMN) were investigated under experimental conditions reflecting either an acute nitrate effect (platelet + control ECs + drug + ADP) or a chronic effect (platelet + 5-day nitrate-treated ECs + ADP). Under acute circumstances, ISDN antiplatelet activities were profoundly magnified by ECs. Aggregation was fully arrested with 5 X 10(-5) M ISDN and an EC number of 2 X 10(4), whereas the same ISDN concentration alone induced 30% inhibition of control aggregation. In contrast, there were no significant changes in platelet aggregation whether incubation was done in the presence or absence of 2-ISMN or 5-ISMN, ISDN metabolites. Long-term exposure of ECs to isosorbide nitrates (ISN) resulted in increased acquired EC changes in ATECD. 5-ISMN was a poor antiplatelet agent but was capable of counteracting ISDN effects on ATECD.(ABSTRACT TRUNCATED AT 250 WORDS)

Impaired cardiac PGI2 and PGE2 biosynthesis in patients with angina pectoris

Thirty-four patients with unstable angina and 14 patients with stable effort angina were investigated for cardiac prostacyclin and prostaglandin E2 (PGE2) biosynthesis, under resting conditions and after cold pressor testing. Twenty-seven patients undergoing cardiac catheterization and coronary angiography for congenital or acquired heart diseases other than coronary artery disease were studied as a control group. Prostacyclin (as 6-keto-PGF1 alpha) and PGE2 were measured by specific radioimmunoassay of blood from the coronary sinus and aorta. During resting conditions no significant differences in plasma 6-keto-PGF1 alpha and PGE2 concentrations were found between coronary sinus and aortic blood, and no transcardiac gradient existed either in control subjects or in patients with stable and unstable angina, respectively. In control subjects cold pressor testing induced a significant increase in 6-keto-PGF1 alpha and PGE2 levels in blood from the different sampling sites, and a significant transcardiac gradient occurred (+11.2 +/- 6.4 pg/ml for 6-keto-PGF1 alpha and +5.1 +/- 3.4 pg/ml for PGE2). However, in angina patients no significant increase in 6-keto-PGF1 alpha and PGE2 plasma levels was found and no transcardiac gradient was formed after cold pressor testing. These results indicate impaired cardiac prostacyclin and PGE2 biosynthesis both in patients with stable and unstable effort angina.

Molsidomine prevents post-ischaemic ventricular fibrillation in dogs

Forty anaesthetized dogs were subjected to left circumflex coronary artery ligation followed by reperfusion. Molsidomine was randomly administered to 20 dogs (50 micrograms kg-1 as an i.v. bolus - 15 min prior to coronary occlusion - followed by an infusion of 0.05 micrograms kg-1 min-1. Standard electrocardiographic leads 2 and 3 were continuously recorded to measure ST segment and delta R% changes and to document both the number of ventricular premature beats and the onset of ventricular fibrillation; aortic pressure and cardiac output were measured; thromboxane B2 plasma levels, platelet aggregation produced by ADP, and molsidomine plasma levels were determined before and at 10, 30 and 75 min after the start of the drug protocol. Molsidomine protected the treated animals from early (10 min) post-ischaemic ventricular fibrillation (0 of 20 vs 6 of 20, P = 0.0202), reduced the incidence of overall post-occlusion ventricular fibrillation (3 of 20 vs 10 of 20, P = 0.0407) and improved the total survival rate (P = 0.0067). In molsidomine treated dogs: mean aortic pressure and the rate-pressure product were lowered 10 min after the start of the drug; immediate post-occlusion (3 min) ST segment changes (0.82 +/- 0.52 vs 1.52 +/- 0.78 mV, P less than 0.025) and delta R% changes (37 +/- 50 vs 90 +/- 84%, P less than 0.025) were less marked; the number of ventricular premature beats was lowered and finally, a progressive decline of platelet aggregation produced by ADP was achieved after 75 min of drug infusion. These results were obtained in the presence of mean plasma levels of molsidomine ranging from 20 to 28 ng ml-1. The time-action curve of the antifibrillatory effect of molsidomine parallels those at the level of post-ischaemic electrocardiographic changes.

[Thromboxane concentrations in the arterial blood of cigarette smokers]

Thromboxane concentrations were investigated in the arterial plasma of 44 patients (25 smokers, 19 nonsmokers) with chronic obstructive arterial disease (COAD) of the lower extremities, documented by angiography. The thromboxane levels were measured by radioimmunoassay. The results indicate that smokers with COAD have significantly higher thromboxane levels than nonsmokers with COAD. The potential effect of nicotine on thromboxane is discussed.

Ginger: inhibition of thromboxane synthetase and stimulation of prostacyclin: relevance for medicine and psychiatry

Ginger, the common spice, has recently been found to act as a potent inhibitor of thromboxane synthetase, raising levels of prostacyclin, without a concomitant rise in PGE2 or PGF2 alpha. Indications for use of ginger to replace either thromboxane inhibitors having serious side effects or prostacyclin are given.

Evidence for isosorbide dinitrate (ISDN) promoting effect on prostacyclin release by the lung and prostacyclin implication in ISDN-induced inhibition of platelet aggregation in humans

We investigated thromboxane B2 (TxB2), 6-keto-PGF1 alpha (6KPGF1 alpha reflecting prostacyclin), PGE2 and PGF2 alpha plasma levels; TxB2, PGE2 and PGF2 alpha platelet production and platelet aggregation response in ascending aorta (reflecting trans-pulmonary difference) and in venous coronary sinus (reflecting transcardiac difference) simultaneously in patients with ischemic heart disease, before and after right-atrial administration of 3 mg ISDN bolus. Transcardiac differences were scarce before as well as after ISDN administration. In aortic blood, ISDN administration into the right atria resulted in a significant increase in prostacyclin and PGF2 alpha plasma levels (472% and 242%, respectively), a decrease of both PGE2 plasma level (-173%) and PGE2 platelet production (-485%) and a marked lowering of platelet aggregation response to ADP, concomittantly. In contrast, TxB2-related features were poorly affected by ISDN. In coronary sinus blood, the aortic increase in 6KPGF1 alpha and PGF2 alpha plasma levels was detected to a lower extent whereas the characteristics of platelet aggregation had returned to control levels. By contrast, PGE2 plasma level (-191%) and PGE2 platelet production (-133%) were lower than prior ISDN administration. The results we report here, strongly support the view that ISDN promotes release of prostacyclin and PGF2 alpha from the lung and inhibit PGE2 production. These prostanoids may be responsible for the concomittant platelet reactivity lowering, thus providing a basis for understanding how ISDN might relieve myocardial ischemia favoring prostanoid mediated vasodilation and inhibition of platelet reactivity.