Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.4.1 (phosphodiesterase)
18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Biomarkers such as C-reactive protein (CRP) and myeloperoxidase (MPO) are elevated in patients with coronary artery disease and confer risk of acute cardiovascular events, such as myocardial infarction (MI) and stroke. More recently, variants in the 5-lipoxygenase-activating protein (FLAP) gene were shown to confer risk to both MI and stroke, effects that appear to be mediated through elevated LTB(4), a chemoattractant mediator shown to be upregulated in patients with MI. Another gene in the leukotriene (LT) pathway, LTA(4) hydrolase, was subsequently found to confer increased risk to MI, effects that were ethnicity-specific with an approximately threefold higher risk in African Americans than in whites. In another study, markers in the phosphodiesterase (PDE) 4D gene were found to confer risk to large-vessel occlusive and cardiogenic stroke. Interestingly, there is a cross-link between the 5-LO and the PDE4D pathways with converging biology. To address the role of an inhibitor of FLAP on biomarkers of MI risk, a randomized placebo-controlled phase II trial was conducted in patients with MI. This trial showed that LTB(4) and MPO production was reduced in whole blood leukocytes that were stimulated with ionomycin and the effects of the inhibitor were dose dependent. Serum CRP and plasma MPO were also reduced at the highest dose, which was well tolerated. These data suggest that LTB(4) is a risk factor of MI and that inhibition of FLAP and the LT pathway produces suppression of biomarkers that are associated with MI risk, including but not limited to LTB(4), MPO, and CRP, supporting the notion that the LTB(4) arm of the LT pathway may play a fundamental role in heart attacks and stroke.
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PMID:Role of FLAP and PDE4D in myocardial infarction and stroke: target discovery and future treatment options. 1663 37

Because most men with erectile dysfunction have underlying vascular disease, it is important to update the cardiovascular safety profile of medications used in the treatment of erectile dysfunction. This retrospective analysis evaluated serious cardiovascular treatment-emergent adverse events (CVTEAEs) reported in 36 clinical trials of tadalafil, a phosphodiesterase-5 inhibitor used for the treatment of erectile dysfunction. A serious CVTEAE was defined as myocardial infarction, cardiovascular death, or cerebrovascular death. In the 36 trials, 12,487 men (mean age 55 years) with erectile dysfunction received tadalafil, with 5,771 patient-years (PYs) of exposure, and 2,047 men (mean age 56 years) received placebo, with 460 PYs of exposure. Tadalafil 2 to 50 mg was taken as needed, 3 times/week, or once a day. Co-morbidities at baseline included hypertension (31%), diabetes (21%), hyperlipidemia (17%), and coronary artery disease (5%). Across all trials, the incidence rate of serious CVTEAEs was 0.40/100 PYs in tadalafil-treated patients and 0.43/100 PYs in placebo-treated patients. In patients taking tadalafil as needed, 3 times/week, or once a day, the incidence rates of serious CVTEAEs ranged from 0.17 to 0.54/100 PYs across placebo-controlled and open-label trials. In conclusion, the incidence rates of serious CVTEAEs were comparable among men with erectile dysfunction taking tadalafil as needed, 3 times/week, or once a day, and these rates were also comparable with those in placebo-treated patients. In this clinical trial population of men with erectile dysfunction, tadalafil was not associated with an increased risk for serious cardiovascular adverse events.
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PMID:Cardiovascular safety update of Tadalafil: retrospective analysis of data from placebo-controlled and open-label clinical trials of Tadalafil with as needed, three times-per-week or once-a-day dosing. 1676 34

The aim of this study was to determine, in an animal model, the effects of tadalafil on myocardial infarct size (IS), hemodynamics and regional myocardial blood flow after myocardial ischemia and reperfusion. Patients with erectile dysfunction (ED) often have risk factors for coronary artery disease. Tadalafil, a long-acting inhibitor of the enzyme phosphodiesterase-5 (PDE5), is used for the treatment of ED; there are no previous data regarding tadalafil in the setting of coronary artery occlusion (CAO). Sprague-Dawley male rats were treated with tadalafil or vehicle (10 mg/kg, by gastric gavage), 2 h before a 30 min CAO. Heart rate was comparable between tadalafil and control groups. Tadalafil reduced mean arterial pressure (P=0.009), systolic (P=0.035) and diastolic (P=0.009) blood pressures during ischemia/reperfusion. Tadalafil significantly reduced IS (42+/-2%) versus controls (54+/-3%) (P=0.006). For the first time, we showed that the PDE5 inhibitor, tadalafil, was well tolerated and cardioprotective in the setting of an experimental myocardial infarction, by substantially reducing ischemic cell death.
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PMID:The phosphodiesterase-5 inhibitor tadalafil reduces myocardial infarct size. 1713 1

Within 6 months of approval by the U.S. Food and Drug Administration (FDA), 5.3 million prescriptions were written for sildenafil citrate. It represented the first clearly effective and FDA-approved oral therapy for the treatment of ED. The chemical structure of sildenafil is very similar to the cyclic guanosine monophosphate molecule with which it competes, in the enzyme phosphodiesterase type-5. Sildenafil binds to the phosphodiesterase-5 enzyme, preventing the breakdown of cyclic guanosine monophosphate through competitive inhibition. The onset of action for sildenafil can be as short as 20 minutes and the duration of action may be as long as three half-lives (18 hours). Anecdotal evidence suggests that many men describe an erectogenic effect for almost 24 hours. The safety of sildenafil has been established in many pre- and postapproval studies at doses as high as eight times the maximum recommended dose. It is likely that the rare instance of myocardial infarction after taking sildenafil as directed, is due more to the activity of sexual intercourse rather than the medication itself. Efficacy have been established in patients with diabetes, parkinsonism, spinal cord injury, and those on antihypertensive (single- and multiple-therapy) agents. It has also been shown to be effective in reversing selective serotonin reuptake inhibitor-induced sexual side effects. Initial concerns about sildenafil with respect to ocular safety were based on misinterpretation of the FDA submission data. The two most common side effects are headache and flushing, both of which are short-lived and easily treated.
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PMID:Four-year review of sildenafil citrate. 1698 12

Platelets play a life-saving role in hemostasis and blood clotting at sites of vascular injury and consequently are similarly involved in the pathological counterpart, namely thrombosis. Thus, anti-platelet therapy has become a mainstay in treatment and/or prophylaxis of conditions like myocardial infarction, stroke and other cardiovascular diseases. Acetyl-salicylic acid (ASA, aspirin) is still the most widely used agent and considered as the prototype antiplatelet drug. Since platelet activation occurs via several pathways that are not influenced by ASA, several other compounds have been developed to add to its beneficial effect. Currently four main classes of antiplatelet agents are available for clinical use: acetyl-salicylic acid (ASA), phosphodiesterase (PDE) inhibitors, thienopyridines and the intravenous GPIIb/IIIa antagonists. This article gives a concise review of these four classes of anti-platelet agents, using ASA as the reference standard.
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PMID:Current developments in anti-platelet therapy. 1704 2

Platelet activation and aggregation is an integral component of the pathophysiology that leads to thrombotic and ischemic diseases such as cerebral stroke, peripheral vascular disease and myocardial infarction. Anti-platelet agents (such as aspirin, ADP receptor antagonists, and GPIIb/IIIa antagonists), phosphodiesterase inhibitors and anti-coagulants are major part of the current treatment towards treating ischemic diseases. However, their limited efficacy in the setting of arterial thrombosis, unfavorable side effect profile and cost-to-benefit issues substantiate the need for the development of newer and more efficacious antithrombotic drugs. Various platelet agonists like adenosine diphosphate (ADP), thrombin and thromboxane A2 (TXA2) activate platelets by acting via their respective surface receptors, which couple to one or more distinct G-proteins belonging to either the G(i), G(q), G(12/13) or G(s) families. Upon activation, each of these G-proteins trigger a series of intracellular signaling cascades, causing the platelets to undergo shape change, secrete their granular contents, generate positive feedback mediators and form stable platelet aggregates. In addition, various G-protein-mediated signaling cascades act in synergy with one another to amplify the magnitude of the platelet responses. The significance of G-proteins as key mediators of the platelet function and normal hemostasis is further corroborated by extensive gene knockout studies. In this review we will limit our discussion to understanding the role of G-proteins in the process of platelet activation and discuss some of the anti-thrombotic drugs that mediate their beneficial effects by interfering with or preventing the initiation of the G-protein signaling pathway.
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PMID:G-protein dependent platelet signaling--perspectives for therapy. 1707 86

Myocardial ischemia-reperfusion injury occurs in a wide spectrum of patients, ranging from survivors of out-of-hospital cardiac arrest to acute myocardial infarction victims as well as patients undergoing cardiac surgery, and represents a major public health burden. This injury contributes significantly to morbidity and mortality, despite meticulous adherence to presently known principles of myocardial protection. Despite the considerable progress that has been made in the field of myocardial protection, high-risk subsets of patients continue to exhibit ischemia-reperfusion-related complications, including prolonged contractile dysfunction (stunning), low-output syndrome, perioperative myocardial infarction, and cardiac failure, requiring prolonged intensive care. Sildenafil, a phosphodiesterase 5 inhibitor, currently licensed for the treatment of erectile dysfunction and pulmonary hypertension has shown great promise in animal studies as a possible pharmacologic agent for cardioprotection. This review article discusses the pharmacology of sildenafil and focuses on the available evidence from animal studies on the potential role of sildenafil for treating ischemia-reperfusion injury with its implications for clinical practice.
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PMID:Cardioprotection with sildenafil: implications for clinical practice. 1716 4

During the past 18 years, sildenafil has evolved from a potential anti-angina drug to an on-demand treatment for erectile dysfunction and more recently to a new orally active treatment for pulmonary hypertension. Recent studies suggest that the drug has powerful cardioprotective effect against ischemia/reperfusion injury, doxorubicin-induced cardiomyopathy and anti-hypertensive effect induced by chronic inhibition of nitric oxide synthase in animals. Based on several recent basic and clinical studies, it is clear that sildenafil and other clinically approved type-5 phosphodiesterase-5 inhibitors including vardenafil and tadalafil will eventually be developed for several cardiovascular indications including essential hypertension, endothelial dysfunction, ischemia/reperfusion injury, myocardial infarction, ventricular remodeling and heart failure.
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PMID:Cardiovascular protection with sildenafil following chronic inhibition of nitric oxide synthase. 1724 65

Nitrates are potent venous dilators and anti-ischemic agents. They are widely used for the relief of chest pain and pulmonary congestion in patients with acute coronary syndromes and heart failure. Nitrates, however, do not reduce mortality in patients with acute coronary syndromes. Combination of nitrates and hydralazine when given in addition to beta-blockers and angiotensin-converting enzyme (ACE) inhibitors reduce mortality and heart failure hospitalizations in patients with heart failure due to left ventricular systolic dysfunction who are of African-American origin. Side effects during nitrate therapy are common but are less well described in the literature compared with the reported side effects in patients with stable angina pectoris. The reported incidence of side effects varies highly among different studies and among various disease states. Headache is the most commonly reported side effect with an incidence of 12% in acute heart failure, 41-73% in chronic heart failure, 3-19% in unstable angina and 2-26% in acute myocardial infarction. The reported incidence of hypotension also differs: 5-10% in acute heart failure, 20% in chronic heart failure, 9% in unstable angina and < 1-48% in acute myocardial infarction, with the incidence being much higher with concomitant nitrate therapy plus angiotensin-converting enzyme inhibitors. Reported incidence of dizziness is as low as 1% in patients with acute myocardial infarction to as high as 29% in patients with heart failure. Severe headaches and/or symptomatic hypotension may necessitate discontinuation of nitrate therapy. Severe life threatening hypotension or even death may occur when nitrates are used in patients with acute inferior myocardial infarction associated with right ventricular dysfunction or infarction, or with concomitant use of phosphodiesterase-5 inhibitors or N-acetylcysteine. Despite the disturbing observational reports in the literature that continuous and prolonged use of nitrates may lead to increased mortality and recurrent myocardial infarction in patients with stable coronary artery disease, no such adverse effects of nitrates have been reported in the large randomized trials in patients with acute myocardial infarction or chronic heart failure.
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PMID:Side effects of using nitrates to treat heart failure and the acute coronary syndromes, unstable angina and acute myocardial infarction. 1768 82

Cyclic nucleotide second messages (cAMP and cGMP) play a central role in signal transduction and regulation of physiologic responses. The only way to inactivate them is to degrade them through the action of phosphodiesterases (PDEs). Recent advances show that PDE4, a cAMP specific phosphodiesterase, has specific functions in regulating the activities of the cardiovascular system. PDE4 is expressed in the cells of cardiovascular systems including cardiomyocytes, vascular smooth muscle cells, and vascular endothelial cells. The expression level of PDE4 is shown to be downregulated in the failure hearts, while it is upregulated in hypertrophied hearts. And PDE4 deficiency in mice is associated with a cardiac phenotype comprised of a progressive, age-related cardiomyopathy, accelerated heart failure after myocardial infarction and exercise-induced arrhythmias. Local levels of cAMP regulate the precise opening of the ryanodine receptor complex (RyR2) which releases calcium at the start of a heartbeat. Loss or inhibition of PDE4 activity increases calcium flow through RyR2, and causes leakiness and heart failure in mice. These finding may show us a new target for treating cardiovascular diseases.
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PMID:[Cyclic nucleotide phosphodiesterase IV expression, activity and targeting in cells of cardiovascular system]. 1770 90


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