Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It has been clearly established that ischemic heart disease, hypertension and ageing affect diastolic function before any change is observed in contractile function. Though an increasingly recognised clinical entity, cardiac failure with normal systolic function still does not have any specific treatment. Phosphodiesterase inhibitors which increase AMPc, in addition to their inotropic and vasodilator effects, accelerate relaxation. Major and isolated abnormalities of relaxation have been demonstrated in vitro in non necrosed tissues of both the dilated and hypertrophic forms of advanced cardiomyopathy. The myocardium seems unable to restore rapidly the low cytosolic calcium concentrations required for the deactivation of the contractile proteins. The underlying mechanisms are probably very complex but a deficit in AMPc production has been demonstrated in very advanced stages of cardiomyopathy. In ischemia, however, the abnormalities of relaxation seem to be directly related to a defect in free energy production inhibiting the sarcoplasmic reticulum calcium pump. If abnormalities of relaxation due to ischemia and those due essentially to a passive mechanism are excluded, phosphodiesterase inhibitors would seem to have pharmacological effects likely to improve diastolic function. Clinical studies confirm the beneficial effects of Milrinone and Enoximone on relaxation and the rapid phase of diastolic filling, both in acute and chronic studies. However, it has not yet been clearly established whether improved diastolic function is due to a direct action on the myocardium or an indirect action due to improved conditions of load. In order to determine the specific effects of phosphodiesterase inhibitors on diastolic function, further research is required.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Effects of phosphodiesterase inhibitors on diastolic function]. 821 93

Earlier studies have demonstrated that nitric oxide (NO) exerts a fast-acting inhibitory influence on endothelial NO synthase (eNOS) enzymatic activity in isolated vascular tissue preparations. The present study was designed to examine the possible effect of NO on eNOS protein expression in cultured endothelial cells and intact animals. Human coronary endothelial cells were incubated with S-nitroso-N-acetyl-penicillamine (SNAP, an NO donor), oxyhemoglobin (HGB, an NO trapping agent), SNAP plus HGB, or inactive vehicle (control). In other experiments, cells were treated with 3-isobutyl-1-methylxanthine (a phosphodiesterase inhibitor), 1H-[1,2, 4]oxadiazolo-[4,3-2]quinoxalin-1-one (ODQ, a guanylate cyclase inhibitor), SNAP plus ODQ, 8-bromo-cGMP (8-Br-cGMP, a cell-permeable cGMP compound), 8-Br-cGMP plus HGB, or inactive vehicle in order to discern the effect of cGMP. The incubations were conducted for 24 hours, and total nitrate plus nitrite production and eNOS protein abundance (Western analysis) were measured. To determine the effect of NO on eNOS expression in vivo, rats were treated with either the NO donor isosorbide dinitrate or placebo by gastric gavage for 48 hours, and aortic eNOS protein expression was examined. The NO donor SNAP markedly depressed, whereas the NO scavenger HGB significantly raised, eNOS protein expression. The downregulatory action of SNAP was completely abrogated by HGB. Phosphodiesterase inhibitor and 8-Br-cGMP downregulated, whereas the guanylate cyclase inhibitor ODQ upregulated eNOS protein expression. The downregulatory action of SNAP was completely overcome by the guanylate cyclase inhibitor ODQ, and the upregulatory action of the NO scavenger HGB was abrogated by 8-Br-cGMP. Administration of NO donor resulted in a marked downregulation of aortic eNOS protein expression in intact animals, thus confirming the in vitro findings. NO serves as a negative-feedback regulator of eNOS expression via a cGMP-mediated process.
Hypertension 1999 Dec
PMID:cGMP-mediated negative-feedback regulation of endothelial nitric oxide synthase expression by nitric oxide. 1060 Nov 24

Phosphodiesterase (PDE) was shown to be downregulated in the failing hearts of transplant recipients, while it was upregulated in hypertrophied hearts induced by isoproterenol and calsequesterin overexpression. We examined the time course of gene expression and the activity of PDE3 and PDE4 in an animal model of salt-induced hypertension, left ventricular hypertrophy, and congestive heart failure (CHF). Dahl salt-sensitive (DS, n = 25) and salt-resistant rats (DR, n = 25) were fed with an 8% NaCl diet after the age of 6 weeks. At 11 weeks (hypertension and hypertrophy stage in DS), PDE4 activity in the heart was higher in DS than in DR. At 18 weeks (hypertension and CHF stage in DS), both PDE3 and PDE4 activity in both the heart and aorta was approximately twofold higher in DS than in DR. The ratios of PDE3 and PDE4 mRNA to GAPDH mRNA in the heart were both approximately twofold higher in DS than in DR at 11 and 18 weeks. The cardiac cyclic adenosine monophosphate content and plasma nitric oxide concentration were higher in DS than in DR at 11 weeks but both of them were lower in DS than in DR at 18 weeks of age. In this animal model, gene expressions of PDE3 and PDE4 were augmented from the hypertrophic stage. PDE3 and PDE4 activities were subsequently enhanced in the CHF stage and seemed to contribute to the development and exacerbation of CHF.
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PMID:Enhanced activities and gene expression of phosphodiesterase types 3 and 4 in pressure-induced congestive heart failure. 1238 34

The numerous controlled clinical trials performed recently in pulmonary arterial hypertension (PAH) can allow us to abandon a clinical-based treatment strategy and adopt an evidence-based therapy. Both uncontrolled and controlled clinical trials with different compounds and procedures are reviewed and compared in order to define the efficacy-to-side-effect ratio of each treatment. A grading system for the level of evidence of treatments based on the number of favorable controlled clinical trials performed with a given compound is adopted; a treatment algorithm based on the evidence derived by clinical trials is proposed. It includes drugs approved by regulatory agencies for the treatment of patients with PAH and/or drugs available on the market for other indications. The algorithm is restricted to patients in New York Heart Association (NYHA) functional class III or IV because they represent the largest population included in controlled clinical trials. In addition, the different treatments have been evaluated mainly in sporadic, idiopathic PAH and in PAH associated with scleroderma or to anorexigen use. Extrapolation of these recommendations to the other PAH subgroups should be done with caution. Oral anticoagulation is proposed for all patients, whereas diuretic treatment and supplemental oxygen are indicated in cases of fluid retention and hypoxemia, respectively. High doses of calcium channel blockers are indicated only in the minority of patients who are responders to acute vasoreactivity testing. Nonresponders to acute vasoreactivity testing, or responders who remain in NYHA functional class III, should be considered candidates for treatment with either an endothelin receptor antagonist or a prostanoid. Continuous intravenous administration of epoprostenol is proposed as rescue treatment in NYHA functional class IV patients. Phosphodiesterase-V inhibitors should be considered in patients who have failed or are not candidates to other therapies. Combination therapy can be attempted in selected cases. Both balloon atrial septostomy and lung transplantation are indicated for refractory patients or where medical treatment is unavailable.
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PMID:Comparative analysis of clinical trials and evidence-based treatment algorithm in pulmonary arterial hypertension. 1519 83

Cyclic nucleotides are important secondary messengers that control many physiologic processes, including smooth muscle contractility. Phosphodiesterases (PDEs) comprise of a superfamily of metallophosphydrolases that specifically cleave the 3',5'-cyclic phosphate moiety of cAMP and/or cGMP to produce the corresponding 5' nucleotide. Currently 21 PDE genes have been cloned and are classified into 11 families (1-11) according to their sequence of homology, biochemical and pharmacological properties. Phosphodiesterase type 5 (PDE5) is one of the members of the superfamily that specifically cleaves cyclic guanosine monophosphate (cGMP), a key intracellular secondary messenger. It is composed of 875 amino acids and was first identified in lungs, vascular and tracheal smooth muscle, and platelets. PDE5 is selectively inhibited by sildenafil, vardenafil and tadalafil, and less selectively by zaprinast and dipyridamole. PDE5 inhibitors have been reported to possess antiplatelet aggregation, weak cardiac inotropic effects and vascular relaxant properties. The tissue distribution of the PDE5 family is relatively restricted compared with other PDEs. Still, recent immunohistochemical and reverse transcriptase-polymerase chain reaction analysis have demonstrated the presence of anti-PDE5 antibodies and PDE5 transcripts in rat cerebellum, kidney, pancreas, aortic smooth muscle cells, heart, placenta, skeletal muscle, and, to a much lesser extent, in other regions of the brain, liver and lungs. Research in this field is intense, with a goal of identifying and developing new, selective PDE5 inhibitors that would be beneficial in a number of maladies, as well as angina, hypertension and erectile dysfunction (ED).
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PMID:Phosphodiesterase 5 enzyme and its inhibitors: update on pharmacological and therapeutical aspects. 1567 22

Phosphodiesterase (PDE)4 inhibitors are effective vasodilators. In addition to the treatment of asthma and other inflammatory diseases, such as chronic obstructive pulmonary disease, wide-spectrum PDE4 inhibitors may also be developed for use in antihypertensive therapy, especially in patients with impaired renal function and elevated pulmonary arterial pressure. Rational approaches to overcoming the intrinsic emetogenic response associated with PDE4 inhibition are discussed, and a dual-action drug development that incorporates L-type Ca2+ channel antagonism and selective PDE4 inhibition is proposed. The potential for research and development of such a dual-action agent should eventually provide healthcare professionals with a new category of therapeutic options with which to attempt to combat hypertension.
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PMID:Novel approaches to using PDE4 inhibitors for antihypertensive therapy. 1581 5

Phosphodiesterase-5 (PDE5) inhibitors and other agents that modulate intracellular cGMP are now emerging as promising, safe, and easy to administer therapies for pulmonary hypertension, with relatively few side effects. Recent studies have shown that PDE5 inhibitors are potent acute pulmonary vasodilators in experimental models that partially reverse established pulmonary arterial hypertension and blunt chronic pulmonary hypertension. In addition, studies on animals reveal that PDE5 inhibitors work in concert with nitric oxide and/or natriuretic peptide levels by enhancing intracellular cGMP and cGMP-mediated vasodilator effects. Further, the combination of PDE5 inhibitors and agents that increase cGMP or cAMP also yields additive beneficial effects on pulmonary hemodynamics in patients with pulmonary arterial hypertension.
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PMID:Pulmonary hypertension: inhaled nitric oxide, sildenafil and natriuretic peptides. 1590 10

The pharmacologic management of hypertension has long been implicated in the genesis of erectile dysfunction; the latter is considered the main reason of nonadherence to antihypertensive therapy. Older-generation antihypertensive drugs (central-acting, beta blockers, diuretics) negatively affect erectile function, while newer-generation agents (calcium antagonists, angiotensin-converting enzyme inhibitors) seem to have neutral effects. Preliminary data with the latest drugs (angiotensin receptor blockers) point to a beneficial effect on erectile function. Phosphodiesterase-5 inhibitors, used for the treatment of erectile dysfunction, can be safely and effectively administered to hypertensive patients (even when on multiple-agent antihypertensive therapy), with a caution regarding alpha blockers. In the case when erectile dysfunction is considered to result from antihypertensive therapy, the treating physician may either add phosphodiesterase-5 inhibitors or substitute current treatment with angiotensin receptor blockers.
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PMID:The effect of antihypertensive drugs on erectile function: a proposed management algorithm. 1668 45

Phosphodiesterase type 5 (PDE5) inhibitors effectively enhance the erectile function of the patients with erectile dysfunction (ED). The use of sildenafil citrate is expanding to a broader extent. Pulmonary artery hypertension has become a new indication of sildenafil. Sildenafil could improve the epithelial function in several vascular conditions in clinical trials. This article reviews the recent advances on basic and clinical studies of ED and sildenafil. On animal models, sildenafil could resume the cavernous epithelial function, up-regulate the protein expression of phosphorylated endothelial NO synthase (eNOS), reverse the decreased intracavernosal pressure (ICP) induced by pudendal artery blood flow restriction or hypoxia. In clinical studies, over 50% of ED patients receiving sildenafil got a fully rigid erection (grade 4 erection). And the same percentage of post-nerve-sparing radical prostatectomy patients receiving sildenafil obtained penile rehabilitation and spontaneously resumed erection sufficient for sexual intercourse. Sildenafil treatment has contributed to the normalization of self-esteem, confidence and sexual harmony in men with ED. All this suggests that a whole rehabilitation from erectile to psychosocial function may become a new goal of ED therapy.
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PMID:[Whole rehabilitation: a new goal of erectile dysfunction therapy]. 1700 39

Phosphodiesterase 5 inhibitors, such as sildenafil, vardenafil and tadalafil, are now approved for the treatment of erectile dysfunction. They inhibit the cGMP-specific isoform 5 of phosphodiesterase, resulting in cGMP accumulation, which, for example in smooth muscle cells, reduces muscular tone. In the cardiovascular system, they slightly reduce arterial systemic blood pressure. This moderate effect was also shown in combination with many antihypertensive drugs. But the important contraindication is the concomitant use of PDE 5 inhibitors with any drug serving as a nitric oxide donor, as this combination can lead to significant arterial hypotension. Caution is needed in patients on alpha-blocking agents. In general, this class of drugs was not shown to exhibit direct deleterious effects on the myocardium or promote arrhythmias. Furthermore, statistical evaluations did not demonstrate an increased risk for patients taking PDE 5 inhibitors in comparison with an adequate control population. Many patients suffering from erectile dysfunction may be characterized by multiple cardiovascular risk factors or even ischemic heart disease, suggesting an increased baseline risk. While in many forms of erectile dysfunction, these agents seem to be very effective, it becomes clear that endothelial dysfunction is an attractive target of PDE 5 inhibitors and may also be the underlying cause in many types of erectile dysfunction. In addition, these agents seem to be very effective in lowering pulmonary arterial pressure, which might provide the opportunity to treat primary and some forms of secondary pulmonary hypertension, perhaps in combination with inhaled nitric oxide or other pulmonary arterial vasodilators. Sildenafil was approved for treatment of primary arterial hypertension in the U.S. in June 2005. Recently, direct cardioprotective effects were described in animal research, resembling preconditioning-like effects, which may, under certain conditions, also be applicable in clinical research.
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PMID:Cardiovascular effects of phosphodiesterase 5 inhibitors. 1701 41


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