Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The clinical significance of phosphodiesterase 5 (PDE5) inhibition is increasingly understood following the pioneering work with sildenafil, and the continuing development programmes for both sildenafil and other marketed inhibitors. Since the initial launch of sildenafil for male erectile dysfunction (MED), approval has now been granted for treatment of pulmonary hypertension, whilst ongoing studies have indicated the potential of PDE5 inhibition for the treatment of a range of additional indications including cardioprotection, memory retention and diabetes. Many of these additional indications are best suited to chronic oral dosing and emphasise the need for highly selective inhibitors with extended duration of action. This article will focus on a research programme aimed at the discovery of improved second-generation PDE5 inhibitors. Essential features of these new PDE5 inhibitors would be enhanced selectivity across the whole PDE family and pharmacokinetics compatible with once daily dosing. Key elements used in this programme are high throughput screening (HTS), exploitation of co-crystal structural information for bound inhibitor in the PDE5 active site, and employment of parallel chemistry to speed progress. Under the guidance of co-crystal structural information, a non-selective HTS hit with poor physicochemistry was initially modified using parallel chemistry to give a lead compound (3) that established a new PDE5 inhibitor series. Notably, (3) displayed physicochemistry compatible with a long plasma half-life, and wide chemical scope. Subsequent optimisation of (3) using crystal structure information to guide design, led rapidly to highly potent and selective PDE5 inhibitors (47, 50). Continued focus on physical properties through ligand efficiency evaluation and lipophilicity (cLogP), maintained the inherently desirable physicochemistry of the initial lead.
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PMID:Design of second generation phosphodiesterase 5 inhibitors. 1730 82

Endothelial dysfunction is universal in diabetes, being intimately involved with the development of cardiovascular disease. The pathogenesis of endothelial dysfunction in diabetes is complex. It is initially related to the effects of fatty acids and insulin resistance on 'uncoupling' of both endothelial nitric oxide synthase activity and mitochondrial function. Oxidative stress activates protein kinase C (PKC), polyol, hexosamine and nuclear factor kappa B pathways, thereby aggravating endothelial dysfunction. Improvements in endothelial function in the peripheral circulation in diabetes have been demonstrated with monotherapies, including statins, fibrates, angiotensin-converting enzyme (ACE) inhibitors, metformin and fish oils. These observations are supported by large clinical end point trials. Other studies show benefits with certain antioxidants, L-arginine, folate, PKC-inhibitors, peroxisome proliferator activated receptor (PPAR)-alpha and -gamma agonists and phosphodiesterase (PDE-5) inhibitors. However, the benefits of these agents remain to be shown in clinical end point trials. Combination treatments, for example, statins plus ACE inhibitors and statins plus fibrates, have also been demonstrated to have additive benefits on endothelial function in diabetes, but there are no clinical outcome data to date. Measurement of endothelial dysfunction in cardiovascular research can provide fresh opportunities for exploring the mechanism of benefit of new therapeutic regimens and for planning and designing large clinical trials.
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PMID:Therapeutic regulation of endothelial dysfunction in type 2 diabetes mellitus. 1765 40

Erectile dysfunction is a common multifactorial complication of diabetes mellitus. In recent years, phosphodiesterase type 5 (PDE-5) inhibitors have been introduced in the management of erectile dysfunction. A recent Cochrane systematic review assessed the effects ofPDE-5 inhibitors in patients with diabetes mellitus and erectile dysfunction from 8 randomized placebo-controlled trials (a total of 1759 participants). The duration of therapy was mainly 12 weeks. The weighted mean difference (WMD) for the International Index of Erectile Function (erectile dysfunction domain) at the end of the study period was 6.6 in favour of the PDE-5 inhibitors arm. The relative risk for answering 'yes' to a global efficacy question ('did the treatment improve your erections?') was 3.8 in the PDE-5 inhibitors arm compared with the control arm. Headache and flushing were the most common adverse events, followed by flu-like symptoms, dyspepsia, myalgia, vision disorders and lower back pain. The overall risk ratio for developing any adverse reaction was 4.8 in the PDE-5 inhibitors arm as compared to the control arm. It was concluded that sufficient evidence exists that treatment with PDE-5 inhibitors can improve erectile dysfunction in diabetic men.
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PMID:[From the Cochrane Library: Phosphodiesterase inhibitors are effective in treating erectile dysfunction in diabetic men]. 1794 26

Cardiovascular diseases like hypertension, hyperlipidemia, diabetes mellitus and obesity are the important predictors of erectile dysfunction (ED). Endothelial dysfunction is proposed to be the underlying cause of ED, just like coronary artery disease. Sildenafil was originally developed to treat angina pectoris but later on was recognized as novel treatment option for impotence. To date, sildenafil has been the most extensively studied PDE (phosphodiesterase)-5 inhibitor. Currently two more PDE-5 inhibitors, tadalafil and vardenafil, are under study. Newer compounds have certain advantages over sildenafil, including greater selectivity for PDE-5 compared with other isoenzymes, absence of effect of food on absorption, faster onset and longer duration of action. PDE-5 inhibitors are emerging as novel therapeutic tools with a potential to protect or enhance endothelial function in humans and to selectively improve regional blood flow. The FDA has recently approved a reformulation of sildenafil for the treatment of pulmonary arterial hypertension. Raynaud's phenomenon, respiratory disorders with ventilation/ perfusion mismatch, congestive cardiac failure, hypertension and stroke are the other conditions in which PDE-5 inhibitors are being tried. It is hoped that this group of drugs will soon emerge as a novel weapon in the armamentarium against various cardiovascular and pulmonary diseases.
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PMID:Novel phosphodiesterase-5 inhibitors: current indications and future directions. 1817 38

Erectile dysfunction is a common complication of diabetes. Clinical practice has no treatment modality specifically designed for the difficult to treat diabetic erectile dysfunction due to the multifactorial and complex pathophysiology of development. PDE type 5 inhibitors are the first-line treatment option. Non-responders should have total and free testosterone checked and testosterone replacement is recommended for hypogonadal patients. For patients who cannot take PDE type 5 inhibitors, or are proven non-responders, the vacuum constriction device continues to serve as a major treatment option. Intracavernosal injection is the most effective medical therapy for diabetic erectile dysfunction despite its high dropout rate. Use of the Medicated Urethral System for Erection to overcome the disadvantages of needle injection is disappointing due to lack of effectiveness. Penile prosthesis will continue to play an important role in diabetic patients with severe erectile dysfunction in coming years.
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PMID:Treatment strategies for diabetic patients suffering from erectile dysfunction. 1820 Nov 48

Erectile dysfunction (ED) is a common complication of diabetes mellitus. Phosphodiesterase-5 (PDE5) inhibitors, which inhibit the breakdown of intracellular cyclic guanosine monophosphate (cGMP), are used to treat diabetic ED. Caffeine, a nonselective PDE inhibitor used in our daily diet, is controversial regarding its effect on erectile function. To investigate the effect of caffeine on erectile function in diabetic rat models and explore the mechanism, male Sprague-Dawley rats were injected with streptozotocin to induce diabetes mellitus. The rats with blood glucose levels above 300 mg/dL were selected for the study. The rats were divided into 4 groups: group A (normal control rats), group B (diabetic rats treated with normal saline), group C (diabetic rats treated with caffeine, 10 mg/kg per day), and group D (diabetic rats treated with caffeine, 20 mg/kg per day). After 8 weeks of treatment, intracavernous pressure (ICP) was measured to assess erectile function. The radioimmunoassay was used to evaluate the level of cGMP in the cavernosum. The ICP and the cavernous cGMP decreased significantly in the diabetic rats compared with normal controls. An 8-week administration of caffeine at the given dosages increased the ICP and cavernous cGMP in diabetic rats. Caffeine consumption improved the erectile function of diabetic rats by up-regulating cavernous cGMP.
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PMID:Effect of caffeine on erectile function via up-regulating cavernous cyclic guanosine monophosphate in diabetic rats. 1842 Oct 70

Aging is associated with a decline in several important health factors in men, including libido. Serum testosterone concentrations also decrease with age, and many age-related clinical features are closely associated with androgen deficiency, including erectile function (ED). Approximately 70% of ED is of organic origin, with the major risk factors being diabetes mellitus, hypercholesterolemia, smoking and chronic medical illnesses. These are also established risk factors for atherosclerosis, which is the predominant predisposing factor of vasculogenic ED. The introduction of phosphodiasterase-5 (PDE-5) inhibitors for the treatment of ED made a significant impact both in terms of clinical efficacy, and increasing the awareness of the condition. In spite of this, some patients fail to respond to PDE-5 inhibitors alone. Both animal and clinical studies indicate that testosterone therapy improves both erectile function and the response to PDE-5 inhibitors in patients with ED and hypogonadism. Indeed, interventional studies demonstrate that testosterone replacement therapy improves erectile function in hypogonadal men who have previously failed to respond to PDE-5 inhibitors alone. Furthermore, it has been demonstrated that the full therapeutic potential of PDE5 inhibitors will only become manifest in a eugonadal state. Recent studies have demonstrated a close relationship between testosterone and ED and suggest that testosterone therapy may be a valuable option for an increasing number of affected men. European guidelines recommend that all men presenting with ED should have their testosterone concentrations measured.
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PMID:Testosterone and erectile dysfunction. 1864 15

The risk for erectile dysfunction is closely linked to cardiovascular morbidities such as coronary heart disease, arterial hypertension, hypercholesterolemia, and diabetes. Molecular analysis revealed an association between the genotypes in single base polymorphisms and the risk for these cardiovascular morbidities. In this review the current knowledge of association studies of single nucleotide polymorphisms and erectile dysfunction and the response to the PDE-5 inhibitor sildenafil is described.
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PMID:[Single base polymorphisms and erectile dysfunction]. 1885 67

Many men with erectile dysfunction (ED) also have associated underlying cardiovascular and metabolic conditions, for which they are likely to be taking medication. Therefore, cardiovascular safety and potential drug interactions are two of the major concerns when using PDE-5 inhibitors in these patients. The PDE-5 inhibitor, vardenafil, is characterized by a rapid onset of action, increased duration of erection, high rates of first-dose success and reliable efficacy that can be maintained with continued use. In both clinical trials and real-life observational studies, vardenafil has demonstrated a favorable efficacy and safety profile in men with ED, including those with associated underlying conditions such as diabetes, hypertension and dyslipidemia. Importantly, the concomitant use of medication for these conditions is not associated with any noteworthy changes in the efficacy and safety of vardenafil. The evidence presented in this review supports the use of vardenafil as a first-line treatment for men with ED, including those with underlying conditions.
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PMID:Vardenafil for the treatment of erectile dysfunction: an overview of the clinical evidence. 2005 11

With the increasing longevity in men and women, sexual health concerns have become more and more important and demands for help are far more common than in the past. Erectile dysfunction's severity and prevalence both increase with aging: since erectile dysfunction is a symptom, physicians should diagnose underlying pathologies that might lead to it instead of focusing on finding a viable treatment. Cardiovascular alterations occur in the elderly, and might lead to erectile dysfunction because of penile blood flow impairment: diabetes, smoking, and sedentary life-style, being risk factors for vascular pathologies, can affect erectile function. Metabolic syndrome and psychological factors are highly prevalent in aging men, and might be other important determinants of erectile dysfunction. Drugs play a role in the pathogenesis of erectile dysfunction, as they can alter hormonal or vascular mechanics needed for achieving or maintaining erection. Alterations in penile vessels can be observed in the elderly: lack of androgens might lead to a reduction of smooth muscle cells content in the penis and an increase in the caliber of vascular spaces. Hypogonadism, when present, should be treated regardless of age; furthermore, synergistic effects have been found during testosterone replacement therapy when using an oral therapy with a PDE-5 inhibitor (sildenafil, vardenafil or tadalafil). These therapies are effective in the elderly, with no increase in the frequency of adverse events, and might also help in providing relief from lower urinary tract symptoms.
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PMID:Erectile dysfunction in aging male. 2051 97


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