New Treatment Options for Erectile Dysfunction in Patients with Diabetes Mellitus

Treatment options for autonomic neuropathies

Autonomic disorders may present in a varied fashion. Symptoms that may require treatment include orthostatic intolerance, gastrointestinal distress, sudomotor abnormalities, and urologic and sexual dysfunction. Realistic treatment goals should be outlined for patients, with the expectations that symptoms can be improved, but that the disease is unlikely to be cured and long-term therapy may be required. Orthostatic intolerance is usually treated by a combination of pharmacologic and nonpharmacologic therapies. Nonpharmacologic therapies include compression stockings, adequate fluid and salt intake, and lifestyle modifications. Polypharmacologic therapy is often the standard and can include a volume-expanding agent (such as fludrocortisone) and a sympathomimetic agent. This combination will improve symptoms dramatically in most patients. Treatment of gastrointestinal disorders should address the particular symptom involved: gastroparesis, constipation, or diarrhea. Treatment of sexual and urogenital dysfunction often requires a combination of pharmacologic intervention and lifestyle modifications for peak effectiveness. Patient education is the cornerstone of treatment in any of the autonomic disorders. Given enough education and motivation, many patients will be able to participate in their treatment, which will provide a feeling of empowerment and control over a disease that is often frustratingly resistant to treatment.

ORIGINAL RESEARCH—ENDOCRINOLOGY: The Effect of Diabetes Mellitus Treatment and Good Glycemic Control on the Erectile Function in Men with Diabetes Mellitus‐Induced Erectile Dysfunction: A Pilot Study

INTRODUCTION

Erectile dysfunction (ED) is a common complication of diabetes mellitus (DM). However, efficacy and/or long-term satisfaction with most of those ED treatment options have been suboptimal.

AIM

In this study we try to evaluate the effect of aggressive treatment and DM regulation on the erectile function in men with DM-induced ED (DMED).

METHODS

Eight type 1 and 17 type 2 diabetic subjects were included into the study. All patients had a measurement of fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1(c)) levels, and completed three sessions of consecutive nights using the RigiScan Plus monitoring device before and after blood sugar control. Also International Index of Erectile Function (IIEF) questionnaire scores were obtained before and after blood sugar control.

RESULTS

Significant improvement was noted in FPG and HbA1(c) levels throughout the treatment period (P < 0.001). However, no statistically significant difference was observed in both IIEF scores and nocturnal penile tumescence and rigidity (nptr) parameters after the dm regulation (p > 0.05).

CONCLUSION

We suggest that there are probably other factors than aggressive treatment and DM regulation for treating DMED, and probably we must consider preventive strategies with pharmacological agents to prevent progressive decrease in erectile function in diabetic patients.

The therapeutic dilemma: how to use short-acting PDE5 inhibitor drugs

In the last few years, the clinical context of the diagnosis and treatment of erectile dysfunction (ED) has changed radically. In fact, oral drug treatment with phosphodiesterase type-5 inhibitors (PDE5-i), licensed in the past years, appeared to offer advantages over other medical approaches in terms of ease of administration and cost. PDE5-i are now widely advocated as first-line therapy for ED. PDE5-i represent a class of orally active drugs for ED, which inhibit PDE5 enzyme and in turn enhance smooth muscle relaxation via prolongation of cyclic GMP action within the cavernous smooth muscle. Although the various types of PDE5-i differ with respect to selectivity and pharmacokinetic profiles, efficacy and safety of these agents are mostly comparable in broad populations of men with erectile ED, including those with diabetes, cardiovascular disease or those taking multiple antihypertensive agents. Aim of this article will be to review the different efficacy and safety profiles of oral short-acting compounds and to give indication for treatment of special populations of men with ED.

Safety and Efficacy of Vardenafil, a Selective Phosphodiesterase 5 Inhibitor, in Patients with Erectile Dysfunction and Arterial Hypertension Treated with Multiple Antihypertensives

INTRODUCTION

Vardenafil, a phosphodiesterase type 5 (PDE5) inhibitor, was evaluated in a prospective trial in the primary care setting involving hypertensive men with ED who were receiving at least one antihypertensive medication.

AIMS

To investigate the safety and efficacy of flexible-dose vardenafil therapy compared with placebo in PDE5 inhibitor-naïve subjects with arterial hypertension and ED.

METHODS

In this multicenter, randomized, double-blind, placebo-controlled study, 354 patients received placebo or vardenafil (5-20 mg) for 12 weeks. Primary efficacy measures were diary responses to the Sexual Encounter Profile (SEP) questions 2 (vaginal insertion) and 3 (maintenance of erection). Additional efficacy measures included positive responses to the Global Assessment Question (GAQ).

RESULTS

Compared with placebo, vardenafil significantly improved mean SEP2 and SEP3 success rates over the 12-week study period (intention-to-treat [ITT] and last observation carried forward [LOCF]) analysis). For LOCF, SEP2 and SEP3 were 83% for vardenafil vs. 58% for placebo and 67% for vardenafil vs. 35% for placebo, respectively (P<0.0001 vs. placebo). Improved erections (GAQ) were experienced by 80% of vardenafil-treated patients at study end, compared with 40% for placebo (P<0.0001, LOCF). The most commonly reported treatment-emerging adverse events were headache (3.1%) and flushing (1.6%), which were mild-to-moderate and transient in nature. Importantly, there were no significant changes in systolic and diastolic blood pressure or heart rate between the vardenafil and placebo groups. The average number of antihypertensives used per patient was 1.5 and 1.4 in the vardenafil and placebo groups, respectively. Both the incidence of adverse events and the ability to maintain an erection were unaffected by stratification into distinct subsets according to the class of antihypertensive medication being received.

CONCLUSION

Vardenafil significantly improves EF in hypertensive men treated with concomitant antihypertensive medication, is well tolerated, and does not significantly affect blood pressure.

Phosphodiesterase-5 Inhibition: the Molecular Biology of Erectile Function and Dysfunction

This article discusses the role of phosphodiesterase-5 (PDE-5) inhibition in the molecular biology of erectile function and dysfunction. Commercially marketed PDE-5 inhibitors are highly specific for PDE-5, and in the face of continuing cyclic GMP (cGMP) synthesis,elevate cellular cGMP. This elevation results from direct competitive inhibition of PDE-5 and from blocking the negative feedback regulation of the enzyme. Elevation of cGMP activates cGMP-dependent protein kinase, which mediates the effects of the cGMP-signaling pathway to decrease smooth muscle tone and dilate penile vascular smooth muscle. By exploiting features of PDE-5 regulatory mechanisms that modulate PDE-5 function, the inhibitors enhance their own potencies.

Microarray analysis reveals novel gene expression changes associated with erectile dysfunction in diabetic rats

To investigate the full range of molecular changes associated with erectile dysfunction (ED) in Type 1 diabetes, we examined alterations in penile gene expression in streptozotocin-induced diabetic rats and littermate controls. With the use of Affymetrix GeneChip arrays and statistical filtering, 529 genes/transcripts were considered to be differentially expressed in the diabetic rat cavernosum compared with control. Gene Ontology (GO) classification indicated that there was a decrease in numerous extracellular matrix genes (e.g., collagen and elastin related) and an increase in oxidative stress-associated genes in the diabetic rat cavernosum. In addition, PubMatrix literature mining identified differentially expressed genes previously shown to mediate vascular dysfunction [e.g., ceruloplasmin (Cp), lipoprotein lipase, and Cd36] as well as genes involved in the modulation of the smooth muscle phenotype (e.g., Kruppel-like factor 5 and chemokine C-X3-C motif ligand 1). Real-time PCR was used to confirm changes in expression for 23 relevant genes. Further validation of Cp expression in the diabetic rat cavernosum demonstrated increased mRNA levels of the secreted and anchored splice variants of Cp. CP protein levels showed a 1.9-fold increase in tissues from diabetic rats versus controls. Immunohistochemistry demonstrated localization of CP protein in cavernosal sinusoids of control and diabetic animals, including endothelial and smooth muscle layers. Overall, this study broadens the scope of candidate genes and pathways that may be relevant to the pathophysiology of diabetes-induced ED as well as highlights the potential complexity of this disorder.

A three-part study to investigate the incidence and potential etiologies of tadalafil-associated back pain or myalgia

The potential mechanisms underlying back pain and/or myalgia experienced by men taking tadalafil were investigated. An integrated analysis of 10 placebo-controlled tadalafil clinical trials (N=1846) showed that the incidence of back pain and/or myalgia was 9.4% in patients receiving tadalafil 10 mg (N=394), 8.3% in patients receiving tadalafil 20 mg (N=883) and 3.7% in placebo-treated patients (N=569). One (0.3%) patient receiving tadalafil 10 mg, six (0.7%) patients receiving tadalafil 20 mg, and no patients receiving placebo discontinued treatment due to back pain and/or myalgia. In a prospective study in healthy volunteers, no substantial changes were observed in laboratory markers indicative of inflammation or muscle damage, and tadalafil did not affect renal plasma flow nor produce lumbar or gluteal myositis by positron emission tomography scan or magnetic resonance imaging. Although the mechanism of back pain and/or myalgia remains unknown, these events appear to be self-limiting and a general effect of phosphodiesterase 5 inhibition.