Search

To obtain more active and selective anti-platelet candidate drugs, we tried to introduce a methyl group at the 5-position and 6-position of the parent benzene ring first time, respectively or simultaneously. The idea could inspect compound with tetra-substituted or penta-substituted characteristics rather than retained classical 1,3,4-position triple substitutions characteristic whether it continues to have anti-platelet activity in vitro. The biological evaluation revealed that most of compounds with this novel structure were more potent than the positive control drug Picotamide. At the concentration of 1.3 μmol/L, using Arachidonic acid as an inducer, it was found that the anti-platelet activity in vitro of five compounds 1a, 1b, 1c, 2f, and 3d was higher than that of Picotamide and the series 1 compounds were generally higher than that of the series 2 and 3. And with ADP as an inducer, the activity in vitro of nine compounds 2a, 2b, 2d, 2f, 2g, 2h, 3a, 3b, and 3c was more elevated than that of Picotamide and the compounds of series 2 and 3 were all evidently even more active than that of series 1. The proportion of newly designed target compounds with active is higher than that of previously developed series of compounds. Based on the in vitro activity results, a preliminary analysis of the structure–activity relationship was deduced. Meanwhile, cytotoxic effects in vitro of 11 target compounds 1b, 1c, 2f, 2a, 2b, 3a, 3b, 3c, 2d, 2g, and 2h on L-929 cells were analyzed, but the data analysis shows that at two concentrations, target compounds have higher effect on L-929 cells than that of control drug Picotamide. The reason or mechanism for obtaining higher in vitro activity and higher cytotoxicity of the target compound under tetra- or penta- substitutions requires further relevant research work before conclusion can be drawn.

Cardiovascular diseases are the most frequent cause of morbidity and mortality worldwide. In order to discover novel compounds with anti-platelet aggregation activities, a series of novel 4-methoxy-1,3-phthalamidesamides (1a–1i) and a series of novel 4-methoxy-1,3-benzenedisulfon-amides (2a–2i) were synthesized and their anti-platelet aggregation activities were evaluated by the turbidimetric method in response to the following agonists: adenosine diphosphate (ADP), arachidonic acid (AA), and Collagen. Those compounds that have better in vitro activities were subjected to cell toxicity tests via cell counting kit-8 (CCK-8) assay. The inhibition rates of anti-platelet in vitro of five compounds 1g (39.45%), 2d (38.87%), 2g (38.55%), 2h (44.56%), and 2i (43.93%) were higher than that of two reference drugs picotamide (36.12%) and aspirin (38.45%) when ADP was selected as an inducer. The inhibition rates of seven compounds 1c (43.63%), 1d (40.02%), 1g (47.42%), 1i (40.45%), 2c (40.11%), 2d (40.45%), and 2i (49.05%) were higher than that of picotamide (34.89%) and aspirin (39.43%) when AA was selected as inducer. And the inhibition rates of five compounds 1d (47.22%), 1i (45.01%), 2d (38.74%), 2e (42.21%), and 2f (39.94%) were higher than picotamide (38.45%) and aspirin (37.08%) when collagen was selected as inducer. Moreover, the effect of cell toxicity exhibited that none of the compounds had obvious cell toxicity against L-929 cells. Therefore, 4-methoxy-1,3-phthalamidesamides (1a–1i) and 4-methoxy-1,3-benzenedisulfon-amides (2a–2i) have the potential to become a novel kind of anti-platelet drugs and deserve further study.

According to the bio-isosterism theory, a series of N, N’-disubstitutedphenyl-4-ethoxylbenzene-1, 3-disulfonamides (5a-p) were designed and synthesized by two steps of reactions including chlorosulfonation and ammonolysis. The structures of all compounds have been confirmed by IR, 1H-NMR, 13C-NMR, and ESI-MS spectra. The in vitro anti-platelet aggregation activities were evaluated by Born’s test induced by adenosine diphosphate (ADP) and arachidonic acid (AA), respectively. The biological evaluation results revealed that compound 5h had the lowest IC50 value (0.32 μM) and the highest inhibition rate (40.9 %) that of three positive control agents clopidogrel (0.41 μM, 23.5 %), aspirin (0.53 μM, 28.9 %), and picotamide (0.76 μM, 32.7 %). Afterwards, compounds with higher activities were selected to further study in vitro cytotoxicity via cell counting kit-8 (CCK-8) assay. The cytotoxicity results indicated that compound 5h had simultaneously the lowest cytotoxicity, while other compounds had no significant relationship between the anti-platelet activities and cytotoxicities. Based on above in vitro anti-platelet activity data, the SAR (Structure Activity Relationship) of the target compounds was preliminarily summarized. In general, N, N’-disubstitutedphenyl-4-ethoxylbenzene-1, 3-disulfonamides have the potential of further study and very likely become safer and more effective anti-platelet agents.

In our present investigation, a series of novel 4-methoxy-1,3-benzenediolyl-hydrazones were designed and synthesized, and their ability to inhibit platelet aggregation was evaluated by adenosine diphosphate (ADP) and arachidonic acid (AA). The structures of the synthesized compounds were confirmed by spectral data. Results demonstrated that the activities of all compounds excelled the positive drug Picotamide (25.1% inhibition rate) and seven compounds (PNN01, PNN03, PNN05, PNN07, PNN09, PNN12, and PNN14) have efficiently inhibited platelet aggregation even higher than Clopidogrel (37.6% inhibition rate) induced by AA. Among them, PNN07 (39.8% inhibition rate) was considered as the most potent analogue. Evaluation of cytotoxic activity of the compounds against L929 cell line revealed that none of the compounds have significant cytotoxicity. Thus, diolylhydrazones derives are potential to be antiplatelet aggregation inhibitors and maybe working in AA-induced selectively.

A series of 4-methoxyisophthalamides (1d–1w) were designed and synthesized and their chemical structures were confirmed by IR, MS, 1H-NMR, and 13C-NMR. The in vitro on anti-platelet aggregation activities of these compounds were assessed by using Born method. Compounds with higher activities were selected to continue research via Cell Counting Kit-8 (CCK-8) assays of their cytotoxicities. Biological screening results revealed four compounds 1h, 1i, 1q, and 1v exhibited higher activities than the control drugs on against the platelet aggregation induced by adenosine triphosphate (ADP). Moreover, compounds 1p and 1q exhibited higher in vitro activities than picotamide induced by collagen at the concentration of 1.3 μM. Compound 1p also possessed anti-platelet aggregation activity superior to the control drug picotamide induced by arachidonic acid (AA) at the concentration of 1.3 μM. At the same time, the result of cytotoxicities exhibited that none of the compounds have significant cytotoxicities. Therefore, 4-methoxyisophthalamides are potential to become novel anti-platelet drugs with high activities and minimum toxicities.

In order to discover antiplatelet drug with novel structure and expand our research scope, total twenty 1,3-benzenedisulfonyl piperazines, were designed and synthesized. These target compounds were divided into two series, namely 4-methoxy-1,3-benzenedisulfonyl piperazines of series 1 and 4-ethoxy-1,3-benzenedisulfonyl piperazines of series 2. With adenosine diphosphate (ADP), arachidonic acid (AA) and collagen as inducers, respectively, the Born turbidimetric method was used to screen the antiplatelet activity in vitro of all target compounds at a concentration of 1.3 μM, with aspirin and picotamide as positive control drugs. And of which, the activities of five compounds for collagen were higher than both picotamide and aspirin. In ADP or AA channel, compounds with an inhibition rate greater than 33% were selected, and their corresponding IC50 values were obtained. According to the IC50, the in vitro activity of one compound for ADP was higher than picotamide, and for AA, two compounds were higher than two positive control drugs and other two compounds only higher than or equal to aspirin. The preliminary analysis of the structure-activity relationship of the target compounds involved in this study was completed. Further, eight compounds exhibiting higher activity in one or two test channels, were subjected to cytotoxicity test on mouse fibroblasts (L929) by CCK-8 method. The in vitro cytotoxicity of most test compounds showed less than or same to control drug picotamide at 10 μM, but at the higher concentration of 100 μM, merely two compounds exhibited higher cell survival rate than that of picotamide. In addition, compound N1,N3-di(4-ethoxy-1,3-phenylenedisulfonyl)bis(1-(m-tolyl)piperazine), which is delivery activity in the three test channels, and another compound N1,N3–di(4-methoxy-1,3-phenylenedisulfonyl)bis(1-(m-tolyl)piperazine), which has the lowest cytotoxic in vitro compound among series 1 and series 2, respectively, are found and selected for simulation analysis as two most likely to dock with the receptor P2Y12. Each of synthesized compounds in silico molecular property and ADME (absorption, distribution, metabolism and excretion) are predicted by using Molinspiration property engine v2018.10 and PreADMET online servers, respectively. Compared with other series of compounds in the previous stage, the two series compounds obtained after the introduction of piperazinyl have a similar in vitro activity.

A series of 4-methoxy diphenyl isophthalates, which are the isosturctural analogs of picotamide, were designed and synthesized using the concept of isosterism. The structures of these new analogs were characterized by all means of spectroscopy, including 1H NMR, 13C NMR, and MS spectra. In vitro antiplatelet aggregation activities of these compounds were investigated by using Born’s test method. Among the 19 compounds tested for both ADP and collagen inducers, six of them (P216–P219 and P220–P221) were found to exhibit higher activity in vitro antiplatelet aggregation than Picotamide. In particular, the compound P220 bearing a nitrooxyl group showed the highest acitivity 72.1% (induced by collagen) and 72.5% (induced by ADP), with IC50 values of 0.30 μM/L induced by ADP (1.3 μM/L) and LD50 > 2500 mg/kg, could have dual mechanism of action. Evaluation of cytotoxic activity of the compounds against L929 cell line revealed that none of the compounds have significant cytotoxicity. Through the careful analysis of in vitro activity data, the SAR of these compounds was preliminarily deduced. The results of this study showed that 4-methoxy diaryl isophthalates derivatives are potential to become an antiplatelet aggregation agents.

Male lower urinary tract symptoms (LUTS) due to bladder outlet obstruction are characterized by abnormal smooth muscle contractions in the lower urinary tract. Alpha1-adrenoceptor antagonists may induce smooth muscle relaxation in the outflow region and represent the current gold standard of medical treatment. However, results may be unsatisfactory or inadequate. Apart from α1-adrenoceptor agonists, smooth muscle contraction in the outflow region may be induced by thromboxane A2 (TXA2), endothelins, or muscarinic receptor agonists. Here, we studied effects of the thromboxane A2 receptor (TP receptor) antagonist picotamide on contraction in the human male bladder trigone and prostate. Carbachol, the α1-adrenoceptor agonist phenylephrine, the thromboxane A2 analog U46619, and electric field stimulation (EFS) induced concentration- or frequency-dependent contractions of trigone tissues in an organ bath. Picotamide (300µM) inhibited carbachol-, phenylephrine-, U46619-, and EFS-induced contractions. Endothelins 1-3 induced concentration-dependent contractions of prostate tissues, which were inhibited by picotamide. Analyses using real time polymerase chain reaction and antibodies suggested expression of thromboxane A2 receptors and synthase in trigone smooth muscle cells. Thromboxane B2 (the stable metabolite of thromboxane A2) was detectable by enzyme immune assay in trigone samples, with most values ranging between 50 and 150pg/mg trigone protein. Picotamide inhibits contractions induced by different stimuli in the human lower urinary tract, including cholinergic, adrenergic, thromboxane A2- and endothelin-induced, and neurogenic contractions in different locations of the outflow region. This distinguishes picotamide from current medical treatments for LUTS, and suggests that picotamide may induce urodynamic effects in vivo.

In our search for new compounds among the structural analogues of the Picotamide acting on antiplatelet aggregation activities, a new series 2 of 4-ethoxyisophthal-amides were synthesized and their in vitro anti-platelet aggregation activities were evaluated by Born's test in comparison with their structural analogues of the series 1 of 4-methoxyisophthal-amides. The results revealed, among the series 2, six compounds 200, 2a, 2k, 2n, 2q and 2r displayed good antiplatelet aggregation activities in vitro induced by 5.0 mM ADP with IC50 values ranging over 0.35 μM - 0.77 μM. And of which, compound 2a exhibited the highest in vitro activity superior than two control drugs Picotamide and Aspirin. From a structure-affnity-'Relationship (SAR) pointed of some insight in the view of the role played by 4-ethoxy derivatives.

Effects of picotamide and zileuton on tonic contractile activity of the rat portal vein preparations, induced by acetylcholine (2.10(-5) mol/1) and phenylephrine (5.10(-7) mol/1) were investigated. Conversion of arachidonic acid products (prostaglandins, leukotrienes) synthesized by endothelial cells, plays an important role in the local regulation of vascular tone. The compounds formed in a cascade of enzymatic transformations can modulate the effect of other vasoactive factors. Picotamide (6,5.10(-5) mol/1) - thromboxane receptor and thromboxane -synthase blocker - depress acetylcholine-induction tonic contraction of isolated segments of portal vein with intact endothelium by 29% and norepinephrine-induction reduction of 45% relative to the control values. The obtained results indicate a participation of thromboxane and/or endoperoxide H2 in this reaction. Partial inhibition of the contractions by 5-lipoxygenase blocker zileuton(4,2.10(-5) mol/1) at 23% relative to control values suggests, that products of lipoxigenase pathways of arachidonic acid conversion are involved in mechanisms of specified reactions. These data indicate complex mechanisms of regulation of vascular tone of the portal vein, which play an important role eicosanoids. Further study of these mechanisms is necessary for the formation of basic knowledge, as well as to elucidate the mechanisms of occurrence and development of pathological conditions of vessels and the development of methods of their correction.

In order to discover novel compounds with anti-platelet aggregation activities, a series of novel 2-methoxy-5-arylamido-N-(pyridin-3-ylmethyl)benzamides (1a-n) were synthesized and their anti-platelet aggregation activities were evaluated by the turbidimetric method in response to the following agonists: adenosine diphosphate (ADP) (5 mM/L), arachidonic acid (AA) (20 µM/L), and collagen (1 mg/mL). Those synthesized compounds that have better in vitro activities were subjected to cell toxicity tests via cell counting kit-8 (CCK-8) assay. The biological evaluation revealed that compound 1a (IC50 : 0.21 µM/L) exhibited the highest anti-platelet aggregation activities when ADP was selected as an inducer, and compound 1b (IC50 : 0.23 µM/L) showed the best activities when AA was selected as inducer, and compound 1m (inhibition rate: 55.06%) had significant anti-platelet aggregation activities when collagen was selected as inducer among all target compounds. Moreover, the effect of cell toxicity exhibited that none of the compounds had obvious cell toxicity against L929 cells. Therefore, 2-methoxy-5-arylamido-N-(pyridin-3-ylmethyl)benzamides have the potential to become a novel kind of anti-platelet drugs and deserve further study.

On the purpose of searching for the structure-activity relationship (SAR) and obtaining novel anti-platelet drugs, 41 4-methoxybenzene-1,3-isophthalamides have been described the synthesis process and in vitro activities on anti-platelet aggregation. The target compounds have been classified into four series: series 1 (ortho-substituted phenyl: 1a-1j), series 2 (meta-substituted phenyl: 2a-2k), series 3 (para-substituted phenyl: 3a-3l) and series 4 (aromatic of no substituted group and aromatic heterocyclic substituted groups: 4a-4h). The chemical structures of the target compounds were confirmed by MS, IR, (1)H NMR, and their in vitro activities on anti-platelet aggregation were tested and assessed by using Born test. The result showed that thirteen compounds 1c, 1d, 1i, 1j, 2g, 3a, 3c, 3d, 3f, 3h, 3l, 4b and 4c have superior anti-platelet aggregation activities than the reference drug Picotamide.

Thromboxane A 2 (TXA 2 ) upregulates and activates NADPH oxidase (Nox) both of which are associated with cardiovascular disease. The aim of this study, therefore, was to investigate the relationship between thromboxane A 2 synthase (TXAS) status and Nox in human vascular smooth muscle cells (hVSMCs), in particular, whether superoxide (O 2 ▪− ) derived from Nox influences TXAS expression and activity. hVSMCs were incubated with TNFα: (10 ng/ml), TXA 2 mimetic U46619 (100 nM), 8-isoprostane F 2α (8-IP; 100 nM) and hypoxia. Expression of TXAS was assessed using western blotting and quantitative PCR. The role of Nox1 and Nox4 was studied using apocynin and mRNA silencing. The effect of the thromboxane receptor antagonist picotamide and of iloprost, a prostacyclin (PGI 2 ) analogue was also studied. TNF-α, U46619 and 8-IP and hypoxia all augmented TXAS expression as well as TXA 2 formation, effects inhibited by apocynin. Nox-1 (but not Nox4) gene silencing inhibited the increase in TXAS expression and activity. Both picotamide and iloprost inhibited the upregulation of TXAS as well as TXA 2 formation induced by TNF-α, U46619 and 8-isoprostane F 2α and hypoxia. It is concluded that upregulation of TXA 2 synthase expression and activity in human VSMCs is mediated by an a priori upregulation of Nox1 and represents a self amplifying cascade. The inhibition of this effect with iloprost consolidates that PGI 2 plays a protective anti-oxidative role in the vasculature and that picotamide and like drugs may be effective in reducing the incidence of cardiovascular disease associated with an oxidative aetiology.

Picotamide has previously been shown to inhibit the platelet binding of thromboxane A2 analogues. Picotamide has been also reported to inhibit thromboxane A2 synthase so that an intracellular target for its action has been postulated. A carrier-mediated active transport for thromboxane A2 (TxA2) was previously reported in platelets. In the present paper the effect of picotamide on the internalization process was assessed. The kinetics of the TxA2 binding to and internalization by human platelets from 6 male healthy volunteers were investigated by a radiolabeled structural TxA2 analogue,125I-PTA-OH, in the absence and in the presence of increasing concentrations of picotamide. The kinetic constants (kobs, k1, and k−1) were calculated by time course experiments according to Weiland and Molinoff. The affinity constant (Km) and maximal uptake velocity (Vmax) values for each subject were determined by the double reciprocal plot of Lineweaver-Burk. The kinetically determined dissociation constant Kd was 10 nmol/L. In the uptake experiments the association rate of the nondisplaceable binding was found to be saturable at increased ligand concentration with a Michaelis-Menten type of kinetics. Picotamide was able to inhibit the internalization process with a Ki of 7100µmol/L

OBJECTIVES To explore the possible role of of 8-isoprostane F2α (8-IPF2α) in the aetiology of erectile dysfunction (ED), as the over-production of superoxide (O2-) derived from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase results in the formation of 8-IPF2α in vascular tissue, which has similar properties to thromboxane A2 (TXA2). TXA2 is vasoconstrictor and up-regulates the expression of NADPH oxidase and phosphodiesterase type 5 (PDE5). MATERIALS AND METHODS Cavernosal vascular smooth muscle cells (CVSMCs) were incubated with 8-IPF2α or the TXA2 analogue, U46619, ±sildenafil, iloprost (a stable prostacyclin [PGI2] analogue) or the nitric oxide (NO) donor NONOate for 16 h. The formation of O2- was then measured, PDE5 expression assessed using Western blotting and PGI2 and 8-IPF2α formation measured using enzyme-linked immunoassays. RESULTS 8-IPF2α promoted the formation of O2-, an effect inhibited by apocynin (an NADPH oxidase inhibitor) and up-regulated the expression of PDE5. Under identical incubation conditions, 8-IPF2α induced an increase in the formation of 8-IPF2α but reduced the formation of PGI2. All, these effects were reversed by sildenafil, iloprost, NONOate and picotamide. CONCLUSIONS These data show that O2- derived from NADPH oxidase influences the relative balance of PGI2 and 8-IPF2α in CVSMCs, which in turn alters the degree of PDE5 expression. This is a novel pathogenic mechanism underlying ED and a novel mechanism of action of sildenafil.

This review describes the current status of antiplatelet therapy in prevention of cardiovascular events of an atherothrombotic nature. The efficacy of aspirin clearly outweighs bleeding risk in secondary prevention, with the relevant exception of patients with peripheral arterial disease (PAD). In trials of primary prevention, aspirin has a limited advantage, which is challenged by the risk of major bleeding. A typical example is primary prevention in type 2 diabetes mellitus, in which a number of trials and a recent meta-analysis have confirmed these limitations. In various settings, clopidogrel has been shown to be marginally more effective than aspirin. Despite a non-negligible bleeding risk, the combination of aspirin-clopidogrel has provided satisfactory results in conditions at high thrombotic risk but rather disappointing results in the long-term treatment of chronic stable cardiovascular disease. The combination of aspirin-dipyridamole was shown to be superior to aspirin alone and equivalent to clopidogrel alone for secondary prevention in cerebrovascular patients. Limitations in the efficacy of antiplatelet agents are partly inherent in their mechanism of action and should not be considered simply as 'treatment failures'. Among other factors, individual variability of response to antiplatelet drugs also plays a meaningful role. Variability of response and 'resistance' may result from drug interactions, baseline and residual platelet hyperactivity, increased platelet turnover, pharmacogenetic factors and others. Poor biological response to aspirin and/or clopidogrel is also frequent in clinical settings such as diabetes, obesity and acute coronary syndromes. The correlation between biological resistance and impaired clinical efficacy of aspirin, and especially clopidogrel, is currently accepted, although with limitations due to the different methods used to assess platelet response. Indeed, the concept of individual 'tailoring' of antiplatelet regimens on the basis of previous laboratory or 'point of care' platelet function tests has been validated in a number of recent trials. The search for and validation of new antiplatelet agents with already known, or totally new, mechanisms of action have also been undertaken with increasing eagerness. Among new adenosine diphosphate receptor antagonists, prasugrel is already registered, and ticagrelor and cangrelor are being developed. New mechanisms being explored are blockade of thrombin-induced platelet aggregation (vorapaxar [SCH 530398]), and inhibition of collagen and ristocetin-mediated platelet functions (DZ-697b). Reappraisal of the neglected class of direct thromboxane A(2) antagonists was followed with less interest. Besides blocking the effects of thromboxane produced from platelets, drugs of this class (such as terutroban sodium and picotamide) may also protect cells from thromboxane produced by sources other than platelets, and some of them may preserve or enhance prostacyclin production. Terutroban is presently being tested in PAD and stroke prevention. Picotamide, marketed in Italy, was shown to reduce cardiovascular events and mortality in studies of PAD patients with diabetes. The results available with thromboxane inhibitors are particularly interesting because they are being obtained in conditions, such as type 2 diabetes and PAD, which are known to be refractory to aspirin.

Andrea Celestini, Francesco VioliIV Divisione di Clinica Medica, Department of Experimental Medicine and Pathology, University of Rome “La Sapienza,” ItalyAbstract: Picotamide is an antiplatelet drug with a dual inhibitory action. Thus, picotamide inhibits both thromboxane A2 (TxA2) receptors and TxA2 synthase and, at variance with aspirin, does not interfere with endothelial prostacyclin (PGI2) production. Two large randomized trials have been performed to assess the clinical efficacy of picotamide in patients at risk of atherothrombosis. The ADEP study compared peripheral artery disease (PAD) patients randomized to picotamide or placebo. This study did not show a significant reduction of cardiovascular events by picotamide but a subgroup analysis showed its potential usefulness in patients with diabetes. To investigate this issue further, the DAVID study recently enrolled diabetic patients with PAD randomized to picotamide versus aspirin; the results showed a significant reduction of overall mortality in the picotamide group. Moreover long-term picotamide treatment in diabetes promotes the reduction of microalbuminuria and the inhibition of growth of carotid plaques. These data suggest that picotamide may represent an interesting drug to be further investigated in future trials in the atherothrombotic setting.Keywords: picotamide, aspirin, diabetes, cardiovascular events, peripheral artery disease

Based on the antiplatelet aggregation mechanism and the bioisosterism principle of the reference drug picotamide, thirteen novel derivatives of arylamide and arylsulfonamide were designed and prepared. The biological activities of these derivatives were investigated. The chemical structures of the target compounds were confirmed by 1 H NMR and IR. The in vitro activities of antiplatelet aggregation of the thirteen target compounds were assessed by Born's method. Compounds 2 b and 8 h have significant antiplatelet aggregation activities, which are superior to the corresponding activity of Picotamide.

Thromboxane (TX) A2, prostacyclin (PGI2), and nitric oxide (NO) regulate platelet function and interaction with the vessel wall. Inhibition of TXA2, implemented synthesis of PGI2, and supply of exogenous NO may afford therapeutic benefit. 2NTX-99 [4-methoxy- N 1-(4- trans -nitrooxycyclohexyl)- N 3-(3-pyridinylmethyl)-1,3-benzenedicarboxamide], a new chemical entity related to picotamide, showed antithromboxane activity and NO donor properties. 2NTX-99 relaxed rabbit aortic rings precontracted with norepinephrine or U46619 (9,11-dideoxy-9α,11α-methanoepoxy-prosta-5 Z ,13 E -dien-1-oic acid; EC50, 7.9 and 17.1 μM, respectively), an effect abolished by 10 μM 1 H -(1,2,4)oxadiazolo(4,3- a )quinoxalin-1-one (ODQ). 2NTX-99 inhibited arachidonic acid (AA)-induced washed platelet aggregation (EC50, 9.8 μM) and TXB2 formation (-71% at 10 μM), and its potency increased in the presence of aortic rings (EC50, 1.4 μM). In whole rabbit aorta incubated with homologous platelets, AA caused contraction and TXA2 formation, reduced by 2NTX-99 (10-40 μM): contraction, -28 and -47%, TXA2 formation, -37 and -75.4%, respectively, with concomitant increase in PGI2. 2NTX-99 (20-40 μM) inhibited U46619-induced aggregation in rabbit platelet-rich plasma (PRP) (-74 ± 6.7 and -96 ± 2.4%, respectively) and inhibited collagen-induced aggregation in human PRP (-48.2 ± 10 and -79.2 ± 6%), whereas ozagrel was ineffective. In human embryonic kidney 293 cells transfected with the TXA2 receptor isophorm α receptor, 2NTX-99 did not compete with the ligand, [3H]SQ29,548 ([3H][1 S -[1α,2β(5 Z ),3β,4α]]-7-[3-[[2-(phenylamino)-carbonyl]hydrazino]methyl]-7-oxabicyclo[2,2,1]-hept-2-yl]-5-heptanoic acid), or prevent inositol phosphate accumulation. After oral administration (50-250 mg/kg), 2NTX-99 inhibited TXA2 production in rat clotting blood (-71 and -91%); at 250 mg/kg, an area under the curve, 0 to 16 h, of 149.5 h/μg/ml and a t 1/2 of 6 h were calculated, with a C max value of 31.8 ± 8.2 μg/ml. An excellent correlation between plasma concentrations and TXA2 inhibition occurs. 2NTX-99 controls platelet function and vessel wall interaction by multifactorial mechanisms and possesses therapeutic potential.

Type 2 diabetes mellitus (DM) and peripheral arterial disease (PAD) are two very relevant cardiovascular (CV) risk factors, which can often be found concurrently in the same patient. The DAVID trial, a double-blind, randomized, aspirin(ASA)-controlled study, has demonstrated that the use of picotamide, a thromboxane A2 synthase and receptor dual inhibitor, is associated with lesser CV morbidity and mortality in this type of patients in comparison to ASA, considered the standard antiplatelet agent. In order to estimate clinical and economic impacts of picotamide in the Italian health care setting, we developed a pharmacoeconomic model based on clinical data from DAVID and national economic parameters and demographics. The base case scenario, which reflects current prices and reimbursement policy (i.e. ASA fully paid for, picotamide out-of-pocket for patients) yielded an incremental cost/effectiveness ratio (ICER) of about 8,500 euro/year of life (YOL) saved, which falls below conventionally adopted willingness to pay thresholds. This cost, however, is totally born by the patient, while the savings on health care expenditures for avoided events (and less ASA) benefit the national health service (NHS). These results may help the physician in explaining the consequences of this choice to his/her patients, facilitating a fully-informed choice. The availability of a theoretical model allowed to explore some alternative scenarios, that indicate that the ICER can be further lowered and the economical burden better distributed through policy changes. In conclusion, the pharmacoeconomic model indicated that picotamide is likely to be a cost/effective option for CV mortality and morbidity prevention in patients with concurrent type 2 DM and PAD and that the level of adoption of this strategy will depend on willingness to pay and policy priorities of the NHS and patients themselves.

Aims Patients with diabetes are at excessive risk of mortality and cardiovascular morbidity. Previous studies suggest that aspirin may be less effective in diabetic patients. In this multi-centre, randomized, double blind trial picotamide, a dual inhibitor of thromboxane A2 synthase and receptor, was compared with aspirin for the prevention of mortality and major cardiovascular events in diabetics with peripheral arterial disease (PAD). Methods and results A total of 1209 adults aged 40–75 years with type 2 diabetes and PAD were randomized to receive picotamide (600 mg bid) or aspirin (320 mg od) for 24 months. The cumulative incidence of the 2 years overall mortality was significantly lower amongst patients who received picotamide (3.0%) than in those who received aspirin (5.5%) with a relative risk ratio for picotamide versus aspirin of 0.55 (95% CI: 0.31–0.98%). Events were reported in 43 patients (7.1%) on picotamide and 53 (8.7%) on aspirin. The combined endpoint of mortality and morbidity had a slightly lower incidence in the picotamide group but this difference did not reach statistical significance. Conclusion Picotamide is significantly more effective than aspirin in reducing overall mortality in type 2 diabetic patients with associated PAD.

OBJECTIVE: Scavenging of vascular endothelial growth factor (VEGF) elevates blood pressure (BP) in patients receiving anti-angiogenic therapy. Similarly, inhibition of circulation VEGF by its soluble receptor fms-like tyrosine kinase-1 (sFlt-1) underlies BP elevation in pre-eclampsia. Both phenotypes are characterized by augmented production of endothelin-1 (ET-1), suggesting a role for ET-1 in anti-angiogenic hypertension. We aimed to assess the effect of VEGF inhibition on ET-1-induced contractility and downstream ET-1 signaling. APPROACH AND RESULTS: Male C57BL/6N mice were treated with either sFlt-1 or vehicle and BP was assessed via tail-cuff. Mean arterial pressure of sFlt-1-treated mice markedly increased compared to vehicle-treated controls (N = 11-12, p

2-1(4-Cyanophenyl)aminol-3-chloro-1,4-naphthalenedione (NQ-Y15) is a dual action drug which acts as a thromboxane A2 (TXA2) synthase inhibitor and TXA2/PGH2 receptor antagonist. In the present study, we examined the effects of NQ-Y15 on Ca2+ mobilization, which is the common event in various types of platelet activation, in arachidonic acid (AA)-stimulated rat platelets. The elevation of cytosolic Ca2+ concentration ([Ca2+]i) induced by AA was inhibited by NQ-Y15 in a concentration-dependent manner. This inhibition-effect of NQ-Y15 was found to be based on the suppression of the rise in [Ca2+]i by the inhibition of both Ca2+ release from internal stores and Ca2+ influx from the extracellular space. Our successive trial was focused on the role of cyclic AMP (cAMP) in the action of NQ-Y15, because cAMP was reported to be increased by dual action drugs such as picotamide and to inhibit the increase in [Ca2+]i. NQ-Y15 was confirmed to increase cAMP in AA-stimulated rat platelets. These results suggested that NQ-Y15 might inhibit the rise in [Ca2+]i in AA-treated rat platelets by increasing cAMP, which is involved in the inhibition of platelet activation.

In a controlled, randomized, 6-year trial the safety and efficacy of picotamide, a dual-action antithromboxane agent, were assessed in 50 patients with type 2 diabetes mellitus at increased risk of thrombotic vascular events. The patients were randomized to two groups of equal size and received 900 mg picotamide daily or placebo. After phase I (double-blind; years 1–2), patients receiving placebo were treated, if necessary, with antiplatelet drugs (aspirin, ticlopidine) while members of the other group continued to receive 600 mg picotamide daily. In the course of the study 21 vascular events occurred: 16 in the group receiving placebo (fatal myocardial infarction, n = 7; non-fatal stroke, n = 3) and five in the group receiving drug (fatal myocardial infarction, n = 2) ( P < 0.005; Fisher's exact test). One patient (placebo group) died of malignant disease. During the initial double-blind phase a total of nine vascular events was observed (six and three in the groups receiving placebo and drug, respectively). Picotamide treatment was well tolerated and no major side-effects were observed during the study periods.

Picotamide is an antiplatelet drug with a peculiar dual mechanism of action: it inhibits thromboxane A2 synthase and antagonizes the pharmacological responses mediated by thromboxane A2 receptor. We investigated the in vitro effect of picotamide on smooth muscle cell migration and proliferation. Picotamide (1–500 μM) decreased human and rat smooth muscle cell proliferation, evaluated as cell number, in a concentration-dependent and reversible manner. Picotamide inhibited DNA synthesis induced by fetal calf serum (10%), platelet-derived growth factor (PDGF-BB (20 ng/ml)), epidermal growth factor (EGF (1 nM)) and (15S)-hydroxy-11,9-(epoxymethano)prosta-5Z,13E-dienoic acid (U46619 (10 μM, thromboxane A2 receptor agonist)). Co-incubation of U46619 together with EGF or PDGF-BB resulted in a marked amplification of [ 3 H ]thymidine incorporation that was completely reversed by picotamide. The drug also inhibited smooth muscle cell migration induced by fibrinogen (600 μg/ml) or PDGF-BB (20 ng/ml) in a concentration-dependent manner. The ability of picotamide to interfere with myocyte migration and proliferation confers, at least in vitro, a pharmacological interest on the compound in atherogenesis.