New Treatment Options for Erectile Dysfunction in Patients with Diabetes Mellitus

LncRNA MALAT1 facilitates BM-MSCs differentiation into endothelial cells and ameliorates erectile dysfunction via the miR-206/CDC42/PAK1/paxillin signalling axis

BACKGROUND

Erectile dysfunction (ED) is a common male sexual dysfunction, with an increasing incidence, and the current treatment is often ineffective.

METHODS

Vascular endothelial growth factor (VEGFA) was used to treat bone marrow-derived mesenchymal stem cells (BM-MSCs), and their cell migration rates were determined by Transwell assays. The expression of the von Willebrand Factor (vWF)VE-cadherin, and endothelial nitric oxide synthase(eNOS) endothelial markers was determined by qRT‒PCR and Western blot analyses. The MALAT1-induced differentiation of BM-MCs to ECs via the CDC42/PAK1/paxillin pathway was explored by transfecting VEGFA-induced BM-MSC with si-MALAT1 and overexpressing CDC42 and PAK1. The binding capacity between CDC42, PAK1, and paxillin in VEGFA-treated and non-VEGFA-treated BM-MSCs was examined by protein immunoprecipitation. MiR-206 was overexpressed in VEGFA-induced BM-MSC, and the binding sites of MALAT1, miR-206, and CDC42 were identified using a luciferase assay. Sixty male Sprague‒Dawley rats were divided into six groups (n = 10/group). DMED modelling was demonstrated by APO experiments and was assessed by measuring blood glucose levels. Erectile function was assessed by measuring the intracavernosa pressure (ICP) and mean arterial pressure (MAP). Penile erectile tissue was analysed by qRT‒PCR, Western blot analysis, and immunohistochemical staining.

RESULTS

MALAT1 under VEGFA treatment conditions regulates the differentiation of BM-MSCs into ECs by modulating the CDC42/PAK1/paxillin axis. In vitro experiments demonstrated that interference with CDC42 and MALAT1 expression inhibited the differentiation of BM-MSCs to ECs. CDC42 binds to PAK1, and PAK1 binds to paxillin. In addition, CDC42 in the VEGFA group had a greater ability to bind to PAK1, whereas PAK1 in the VEGFA group had a greater ability to bind to paxillin. Overexpression of miR-206 in VEGFA-induced BM-MSCs demonstrated that MALAT1 competes with the CDC42 3'-UTR for binding to miR-206, which in turn is involved in the differentiation of BM-MSCs to ECs. Compared to the DMED model group, the ICP/MAP ratio was significantly greater in the three BM-MSCs treatment groups.

CONCLUSIONS

MALAT1 facilitates BM-MSC differentiation into ECs by regulating the miR-206/CDC42/PAK1/paxillin axis to improve ED. The present findings revealed the vital role of MALAT1 in the repair of BM-MSCs for erectile function and provided new mechanistic insights into the BM-MSC-mediated repair of DMED.

Poly-L-lactic acid/gelatin electrospun membrane-loaded bone marrow-derived mesenchymal stem cells attenuate erectile dysfunction caused by cavernous nerve injury

Radical prostatectomy (RP) can cause neurogenic erectile dysfunction (ED), which negatively affects the quality of life of patients with prostate cancer. Currently, there is a dearth of effective therapeutic strategies. Although stem cell therapy is promising, direct cell transplantation to injured cavernous nerves is constrained by poor cell colonization. In this study, poly-L-lactic acid (PLLA)/gelatin electrospun membranes (PGEM) were fabricated to load bone marrow-derived mesenchymal stem cells (BM-MSCs) as a patch to be placed on injured nerves to alleviate ED. This study aimed to establish a promising and innovative approach to mitigate neurogenic ED post-RP and lay the foundation for modifying surgical procedures. Electrospinning and molecular biotechnology were performed in vitro and in vivo, respectively. It was observed that PGEM enhanced the performance of BM-MSCs and Schwann cells due to their excellent mechanical properties and biocompatibility. The transplanted PGEM and loaded BM-MSCs synergistically improved bilateral cavernous nerve injury-related ED and the corresponding histopathological changes. Nevertheless, transplantation of BM-MSCs alone has been verified to be ineffective. Overall, PGEM can serve as an ideal carrier to supply a more suitable survival environment for BM-MSCs and Schwann cells, thereby promoting the recovery of injured cavernous nerves and erectile function.

d-Galactose induces the senescence and phenotype switch of corpus cavernosum smooth muscle cells

Studies regarding age-related erectile dysfunction (ED) based on naturally aging models are limited by their high costs, especially for the acquisition of primary cells from the corpus cavernosum. Herein, d-galactose ( d-gal) was employed to accelerate cell senescence, and the underlying mechanism was explored. As predominant functional cells involved in the erectile response, corpus cavernosum smooth muscle cells (CCSMCs) were isolated from 2-month-old rats. Following this, d-gal was introduced to induce cell senescence, which was verified via β-galactosidase staining. The effects of d-gal on CCSMCs were evaluated by terminal deoxynucleoitidyl transferase dUTP nick-end labeling (TUNEL), immunofluorescence staining, flow cytometry, western blot, and quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, RNA interference (RNAi) was carried out for rescue experiments. Subsequently, the influence of senescence on the corpus cavernosum was determined via scanning electron microscopy, qRT-PCR, immunohistochemistry, TUNEL, and Masson stainings. The results revealed that the accelerated senescence of CCSMCs was promoted by d-gal. Simultaneously, smooth muscle alpha-actin (alpha-SMA) expression was inhibited, while that of osteopontin (OPN) and Krüppel-like factor 4 (KLF4), as well as fibrotic and apoptotic levels, were elevated. After knocking down KLF4 expression in d-gal-induced CCSMCs by RNAi, the expression level of cellular alpha-SMA increased. Contrastingly, the OPN expression, apoptotic and fibrotic levels declined. In addition, cellular senescence acquired partial remission. Accordingly, in the aged corpus cavernosum, the fibrotic and apoptotic rates were increased, followed by downregulation in the expression of alpha-SMA and the concurrent upregulation in the expression of OPN and KLF4. Overall, our results signaled that d-gal-induced accelerated senescence of CCSMCs could trigger fibrosis, apoptosis and phenotypic switch to the synthetic state, potentially attributed to the upregulation of KLF4 expression, which may be a multipotential therapeutic target of age-related ED.

Differential Gene Expression in the Penile Cavernosum of Streptozotocin-Induced Diabetic Rats

PURPOSE

Men with diabetes mellitus (DM) often present with severe erectile dysfunction (ED). This ED is less responsive to current pharmacological therapies. If we know the upregulated or downregulated genes of diabetic ED, we can inhibit or enhance the expression of such genes through RNA or gene overexpression.

METHODS

To investigate gene changes associated with ED in type 1 DM, we examined the alterations of gene expression in the cavernosum of streptozotocin-induced diabetic rats. Specifically, we considered 11,636 genes (9,623 upregulated and 2,013 downregulated) to be differentially expressed in the diabetic rat cavernosum group (n=4) compared to the control group (n=4). The analysis of differentially expressed genes using the gene ontology (GO) classification indicated that the following were enriched: downregulated genes such as cell cycle, extracellular matrix, glycosylphosphatidylinositol-anchor biosynthesis and upregulated genes such as calcium signaling, neurotrophin signaling, apoptosis, arginine and proline metabolism, gap junction, transforming growth factor-β signaling, tight junction, vascular smooth muscle contraction, and vascular endothelial growth factor (VEGF) signaling. We examined a more than 2-fold upregulated or downregulated change in expression, using real time polymerase chain reaction. Analysis of differentially expressed genes, using the GO classification, indicated the enrichment.

RESULTS

Of the 41,105 genes initially considered, statistical filtering of the array analysis showed 9,623 upregulated genes and 2,013 downregulated genes with at least 2-fold changes in expression (P<0.05). With Bonferroni correction, SLC2A9 (solute carrier family 2 member 9), LRRC20 (leucine rick repeat containing 20), PLK1 (polo like kinase 1), and AATK (apoptosis-associated tyrosine kinase) were all 2-fold changed genes.

CONCLUSION

This study broadens the scope of candidate genes that may be relevant to the pathophysiology of diabetic ED. In particular, their enhancement or inhibition could represent a novel treatment for diabetic ED.

Erectile disfunction medical treatment with phosphodiesterase 5 inhibitors (PDE5i) in patients with retinitis pigmentosa and side effects

Retinitis pigmentosa represents a heterogeneous group of degenerative hereditary pathologies of the retinal photoceptors, some forms mainly affect the cones and others the rods. The prevalence of the disease is of 1 case per 3000-5000 inhabitants, in 80-90% of cases these are forms with prevalent involvement of the rods (RCD) and in 10-20% of cases of forms with prevalent involvement of the cones (CRD) [...].

Revisiting the Regenerative Therapeutic Advances Towards Erectile Dysfunction

Erectile dysfunction (ED) is an inability to attain or maintain adequate penile erection for successful vaginal intercourse, leading to sexual and relationship dissatisfaction. To combat ED, various surgical and non-surgical approaches have been developed in the past to restore erectile functions. These therapeutic interventions exhibit significant impact in providing relief to patients; however, due to their associated adverse effects and lack of long-term efficacy, newer modalities such as regenerative therapeutics have gained attention due to their safe and prolonged efficacy. Stem cells and platelet-derived biomaterials contained in platelet-rich plasma (PRP) are thriving as some of the major therapeutic regenerative agents. In recent years, various preclinical and clinical studies have evaluated the individual, as well as combined of stem cells and PRP to restore erectile function. Being rich in growth factors, chemokines, and angiogenic factors, both stem cells and PRP play a crucial role in regenerating nerve cells, myelination of axons, homing and migration of progenitor cells, and anti-fibrosis and anti-apoptosis of damaged cavernous nerve in corporal tissues. Further, platelet-derived biomaterials have been proven to be a biological supplement for enhancing the proliferative and differentiation potential of stem cells towards neurogenic fate. Therefore, this article comprehensively analyzes the progresses of these regenerative therapies for ED.

Advantages of Phosphodiesterase Type 5 Inhibitors in the Management of Glucose Metabolism Disorders: A Clinical and Translational Issue

Among metabolic diseases, carbohydrate metabolism disorders are the most widespread. The most common glucose pathological conditions are acquired and may increase the risk of type 2 diabetes, obesity, heart diseases, stroke, and kidney insufficiency. Phosphodiesterase type 5 inhibitors (PDE5i) have long been used as an effective therapeutic option for the treatment of erectile dysfunction (ED). Different studies have demonstrated that PDE5i, by sensitizing insulin target tissues to insulin, play an important role in controlling the action of insulin and glucose metabolism, highlighting the protective action of these drugs against metabolic diseases. In this review, we report the latest knowledge about the role of PDE5i in the metabolic diseases of insulin resistance and type 2 diabetes, highlighting clinical aspects and potential treatment approaches. Although various encouraging data are available, further in vivo and in vitro studies are required to elucidate the mechanism of action and their clinical application in humans.

Therapeutic Strategies for Erectile Dysfunction With Emphasis on Recent Approaches in Nanomedicine

This review addressed erectile dysfunction, regarding pathophysiology and therapeutic strategies. The line of treatment includes phosphodiesterase type-5 inhibitors and other types of therapy like topical and stem-cell transplant. Scientific literature was assessed to investigate the impact of nanotechnology on erectile dysfunction therapy. Various nanotechnology approaches were applied, like vesicular systems, lipid-based carriers, nanocrystals, dendrimers, liquid crystalline systems and nanoemulsions. Smart nano-systems can alter the landscape of the modern pharmaceutical industry by re- investigation of pharmaceutically suboptimal but biologically active entities for treatment of erectile dysfunction which were previously considered undeveloped.

Fluted pumpkin (Telfairia occidentalis) seed modulates some markers of erectile function in isolated rat's corpus cavernosum: Influence of polyphenol and amino acid constituents

Pumpkin seeds are often used in traditional medicine in the management of erectile dysfunction. However, there is insufficient information about the possible biochemical rationale behind this practice. Hence, this study investigated the influence of fluted pumpkin seed on critical enzymes involved in erectile function in isolated rats' corpus cavernosum in vitro. The phenolics and amino acid contents of fluted pumpkin seed were determined using HPLC-DAD and GC-PFPD analyses respectively. The aqueous extract of the fluted pumpkin seed significantly (p < .05) scavenged free radicals and inhibited PDE-5, arginase, AChE, and ACE in rats' corpus cavernosum in a concentration-dependent pattern. Quercitrin and luteolin were the most dominant phenolics, while arginine, aspartate, and cysteine were the most aboundant amino acid constituents. The positive modulatory effect of the fluted pumpkin seed on these critical markers of erectile function could be attributed to its polyphenolics and amino acid constituents. PRACTICAL APPLICATIONS: This study brought to limelight the medicinal importance of fluted pumpkin seed in erectile functions. Therefore, this seed could be used as a functional food ingredient in the management of erectile dysfunctions and also in improving erectile functions in men. In addition, the dominant phenolics and amino acid constituents of this seed might be an effective nutraceutical in enhancing erections in men.

Sexual stimulant effects of the mixture of Mondia whitei, Dracaena arborea, and Bridelia ferruginea in normal and prediabetic male Wistar rats

Background We investigated the effects of a polyherbal formulation prepared from the extracts of Mondia whitei (Periplocaceae), Dracaena arborea (Dracaenaceae), and Bridelia ferruginea (Euphorbiaceae) (MDB) on the sexual behavior of normal rats (NR) and prediabetic rats (PR). Methods Male Wistar rats were administered with drinking fructose solution (21%) or tap water for 16 weeks. After induction of prediabetic status, NR (n = 30) and PR (n = 30) were randomly distributed into 10 groups of six animals each and orally treated with distilled water (10 mL/kg), sildenafil citrate (5 mg/kg), or MDB (50, 100, or 500 mg/kg) for 21 days. Sexual behavior parameters per series (S) of ejaculation were evaluated on days 1, 7, 14, and 21. Results Drinking fructose solution (21%) induced prediabetic status in rats, characterized by a significant (p < 0.01) increase in glycemia by 43.41% compared with the control group. MDB improved sexual performances of NR and PR by increasing the mount frequency (MF) and the intromission frequency (IF) as well as the number of rats capable of ejaculating. For instance, the MF and the IF were significantly increased in animals administered with MDB for 7 (50 mg/kg, S1 and S2), 14 (100 mg/kg, S3), or 21 days (100 or 500 mg/kg, S2). This increase was more pronounced on days 7 and 14 in NR and PR treated with sildenafil citrate or MDB extracts, respectively. Conclusions The mixture of MDB improved sexual activity in NR and PR. This result may further justify the traditional use of these plants as sexual performance enhancers.

Erectile dysfunction treated with intracavernous stem cells: A promising new therapy?

In the past decades, great interest has been shown in the development of new therapies for erectile dysfunction. Stem cell therapy has generated promising results in numerous preclinical trials in animal models, which is why has led to the development of the first clinical trials in humans. The main cause involved in the pathophysiology of erectile dysfunction is vascular damage related to endothelial and neuronal injury. The interest in stem cell therapy is justified by their capability to differentiate into specific damaged tissues, including endothelium and nervous tissue, and induction of the host own cell proliferation. Despite the great effort of the many studies carried out to date, knowledge about biological effects, therapeutic efficacy and safety of stem cells therapy for erectile dysfunction is still very limited.

Does Type 1 Diabetes Modify Sexuality and Mood of Women and Men?

Background: Sexual disorders occurring in women and men with type 1 diabetes have not been sufficiently investigated and described until now. This study attempts to evaluate sexuality in women and men. Methods: Altogether, the study comprised 115 patients with type 1 diabetes and 105 healthy people constituting the control group. All the studied persons underwent survey studies determining sexuality using the Female Sexual Function Index (FSFI-19) in women and the International Index of Erectile Function (IIEF-15) in men, and the occurrence of depression using the Beck Depression Inventory. The acceptance of illness among patients with diabetes was examined using the Acceptance of Illness Scale questionnaire. Results: In 35% of the examined women with diabetes, the study demonstrated sexual dysfunction as determined by total FSFI. The point values of all the investigated FSFI domains were significantly lower in women with diabetes than in healthy ones (p < 0.001). Erectile dysfunction occurred in 50% of the studied men with diabetes and in 23% of the control group of men (p = 0.0017). Conclusions: Type 1 diabetes leads to sexual disorders which occur in 1/3 of women and in 1/2 of men. Sexual disorders in patients with diabetes more frequently occur in men, persons with coexisting complications of diabetes, and in those with a concentration of glycated hemoglobin higher than 6.5%.

The phosphodiesterase 5 inhibitor tadalafil regulates lipidic homeostasis in human skeletal muscle cell metabolism

PURPOSE

Tadalafil seems to ameliorate insulin resistance and glucose homeostasis in humans. We have previously reported that tadalafil targets human skeletal muscle cells with an insulin (I)-like effect. We aim to evaluate in human fetal skeletal muscle cells after tadalafil or I: (i) expression profile of I-regulated genes dedicated to cellular energy control, glycolitic activity or microtubule formation/vesicle transport, as GLUT4, PPARγ, HK2, IRS-1, KIF1C, and KIFAP3; (ii) GLUT4, Flotillin-1, and Caveolin-1 localization, all proteins involved in energy-dependent cell trafficking; (iii) activation of I-targeted paths, as IRS-1, PKB/AKT, mTOR, P70/S6K. Free fatty acids intracellular level was measured. Sildenafil or a cGMP synthetic analog were used for comparison; PDE5 and PDE11 gene expression was evaluated in human fetal skeletal muscle cells.

METHODS

RTq-PCR, PCR, western blot, free fatty acid assay commercial kit, and lipid stain non-fluorescent assay were used.

RESULTS

Tadalafil upregulated I-targeted investigated genes with the same temporal pattern as I (GLUT4, PPARγ, and IRS-1 at 3 h; HK2, KIF1C, KIFAP3 at 12 h), re-localized GLUT4 in cell sites positively immune-decorated for Caveolin-1 and Flotillin-1, suggesting the involvement of lipid rafts, induced specific residue phosphorylation of IRS-1/AKT/mTOR complex in association with free fatty acid de novo synthesis. Sildenafil or GMP analog did not affect GLUT4 trafficking or free fatty acid levels.

CONCLUSION

In human fetal skeletal muscle cells tadalafil likely favors energy storage by modulating lipid homeostasis via IRS-1-mediated mechanisms, involving activation of I-targeted genes and intracellular cascade related to metabolic control. Those data provide some biomolecular evidences explaining, in part, tadalafil-induced favorable control of human metabolism shown by clinical studies.

Sim1 Neurons Are Sufficient for MC4R-Mediated Sexual Function in Male Mice

Sexual dysfunction is a poorly understood condition that affects up to one-third of men around the world. Existing treatments that target the periphery do not work for all men. Previous studies have shown that central melanocortins, which are released by pro-opiomelanocortin neurons in the arcuate nucleus of the hypothalamus, can lead to male erection and increased libido. Several studies specifically implicate the melanocortin 4 receptor (MC4R) in the central control of sexual function, but the specific neural circuitry involved is unknown. We hypothesized that single-minded homolog 1 (Sim1) neurons play an important role in the melanocortin-mediated regulation of male sexual behavior. To test this hypothesis, we examined the sexual behavior of mice expressing MC4R only on Sim1-positive neurons (tbMC4Rsim1 mice) in comparison with tbMC4R null mice and wild-type controls. In tbMC4Rsim1 mice, MC4R reexpression was found in the medial amygdala and paraventricular nucleus of the hypothalamus. These mice were paired with sexually experienced females, and their sexual function and behavior was scored based on mounting, intromission, and ejaculation. tbMC4R null mice showed a longer latency to mount, a reduced intromission efficiency, and an inability to reach ejaculation. Expression of MC4R only on Sim1 neurons reversed the sexual deficits seen in tbMC4R null mice. This study implicates melanocortin signaling via the MC4R on Sim1 neurons in the central control of male sexual behavior.

High prevalence of erectile dysfunction in diabetes: a systematic review and meta-analysis of 145 studies

Erectile dysfunction may be common among men with diabetes, but its prevalence is still debated. We aimed to assess the relative prevalence of erectile dysfunction in diabetes searching major databases from inception to November 2016 for studies reporting erectile dysfunction in men with Type 1 and Type 2 diabetes mellitus. We conducted a meta-analysis of the prevalence [and 95% confidence intervals (95% CIs)] of erectile dysfunction in diabetes compared with healthy controls, calculating the relative odds ratios (ORs) and 95% CIs. A random effect model was applied. From 3747 initial hits, 145 studies were included representing 88 577 men (age: 55.8 ± 7.9 years). The prevalence of erectile dysfunction in diabetes overall was 52.5% (95% CI, 48.8 to 56.2) after adjusting for publication bias, and 37.5%, 66.3% and 57.7% in Type 1, Type 2 and both types of diabetes, respectively (P for interaction < 0.0001). The prevalence of erectile dysfunction was highest in studies using the Sexual Health Inventory for Men (82.2%, 17 studies, P for interaction < 0.0001). Studies with a higher percentage of people with hypertension moderated our results (beta = 0.03; 95% CI, 0.008 to 0.040; P = 0.003; R²  = 0.00). Compared to healthy controls (n = 5385) men with diabetes (n = 863) were at increased odds of having erectile dysfunction (OR 3.62; 95% CI, 2.53 to 5.16; P < 0.0001; I²  = 67%, k = 8). Erectile dysfunction is common in diabetes, affecting more than half of men with the condition and with a prevalence odds of approximately 3.5 times more than controls. Our findings suggest that screening and appropriate intervention for men with erectile dysfunction is warranted.

Current use of phosphodiesterase inhibitors in urology

The causes of male erectile dysfunction (ED) are quite variable and are now commonly divided into etiologies such as ischemia, smooth muscle damage, or altered blood flow. Although varying rates of ED have been reported in literature, the number of men with ED is projected to increase worldwide by 2025 to approximately 322 million. Since the introduction of phosphodiesterase 5 (PDE5) inhibitors, there has been a paradigm shift in the treatment of ED because PDE5 inhibitors address a broad spectrum of etiologies for ED. Today, the American Urological Association recommends the use of three PDE5 inhibitors (sildenafil, tadalafil, and vardenafil) as a first-line therapy for the treatment of ED. This review evaluates the pharmacological mechanism of PDE5 inhibitors along with the impact and use of sildenafil, vardenafil, tadalafil, and avanafil. By increasing intracellular cGMP levels, PDE5 inhibitors have been shown to be effective in the treatment of ED. Through their effects on other cellular signaling pathways, PDE5 inhibitors have the potential for treating other urologic conditions as well. The use of PDE5 inhibitors can also be combined to produce a synergistic effect in conditions such as male hypogonadism and benign prostatic hyperplasia in addition to ED.

Treating Diabetic Neuropathy: Present Strategies and Emerging Solutions

Diabetic peripheral neuropathies (DPN) are a heterogeneous group of disorders caused by neuronal dysfunction in patients with diabetes. They have differing clinical courses, distributions, fiber involvement (large or small), and pathophysiology. These complications are associated with increased morbidity, distress, and healthcare costs. Approximately 50% of patients with diabetes develop peripheral neuropathy, and the projected rise in the global burden of diabetes is spurring an increase in neuropathy. Distal symmetrical polyneuropathy (DSPN) with painful diabetic neuropathy, occurring in around 20% of diabetes patients, and diabetic autonomic neuropathy (DAN) are the most common manifestations of DPN. Optimal glucose control represents the only broadly accepted therapeutic option though evidence of its benefit in type 2 diabetes is unclear. A number of symptomatic treatments are recommended in clinical guidelines for the management of painful DPN, including antidepressants such as amitriptyline and duloxetine, the γ-aminobutyric acid analogues gabapentin and pregabalin, opioids, and topical agents such as capsaicin. However, monotherapy is frequently not effective in achieving complete resolution of pain in DPN. There is a growing need for head-to-head studies of different single-drug and combination pharmacotherapies. Due to the ubiquity of autonomic innervation in the body, DAN causes a plethora of symptoms and signs affecting cardiovascular, urogenital, gastrointestinal, pupillomotor, thermoregulatory, and sudomotor systems. The current treatment of DAN is largely symptomatic, and does not correct the underlying autonomic nerve deficit. A number of novel potential candidates, including erythropoietin analogues, angiotensin II receptor type 2 antagonists, and sodium channel blockers are currently being evaluated in phase II clinical trials.

Phosphodiesterase-5 inhibitors for erectile dysfunction in patients with diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Patients with diabetes mellitus frequently experience erectile dysfunction. This systematic review and meta-analysis were conducted to find efficacy and tolerability of phosphodiesterase 5 (PDE5) inhibitors in patients with diabetes mellitus experiencing erectile dysfunction.

METHODOLOGY

Electronic searches were carried out to identify English language peer-reviewed randomized controlled trials (RCTs), which reported clinical efficacy of any PDE5 inhibitor in patients with diabetes mellitus having erectile dysfunction. Effect sizes were computed using Cohen's d, and I(2) -test was used to assess heterogeneity. Pooled mean effect sizes were computed using random-effects model. Number needed to treat (NNT), and the adverse event rates were computed.

RESULTS

The systematic review included a total of 17 studies yielding 25 comparisons. Three studies were open RCTs while others were double-blind RCTs. The pooled mean effect size of any PDE5 inhibitor over placebo was 0.926 (95% confidence intervals [CI]: 0.864-0.987; I(2) =26.3). The pooled mean effect size for sildenafil was 1.198 (CI: 1.039-1.357; I(2) =0), for tadalafil was 0.910 (CI: 0.838-0.981; I(2) =33.6), and for vardenafil was 0.678 (CI: 0.627-0.729; I(2) =0). In pooled analysis, the NNT for sildenafil, tadalafil, vardenafil and any PDE5 inhibitor was 2.4, 2.6, 4.1 and 3.0 respectively. The most common side effects were headache, flushing, and nasal congestion.

CONCLUSIONS

PDE5 inhibitors are effective and safe medications for the treatment of sexual dysfunction in patients with diabetes mellitus experiencing erectile dysfunction.

DPP-4 inhibition improves a sexual condition?

Erectile dysfunction (ED) is a condition of persistent inability to achieve or maintain an erection sufficient for satisfactory sexual intercourse. The etiology of ED is predominantly vascular, explained by nitric oxide metabolism disturbances being in the background. Nitric oxide enhancing drugs like phosphodiesterase 5 inhibitors, which delay the breakdown of nitric oxide, are widely used, but still without complete success. Restauration of endogenous nitric oxide production focused on improving endothelial dysfunction could be a more effective way of treatment, addressing also other vessels in the body and preventing more serious cardiovascular disease. Endothelial progenitor cells are bone marrow-derived cells found also in human circulation, and may under circumstances be embedded into the vascular intima leading to improvements in nitric oxide production and thus in endothelial function in many organs, including the penis. In this article we hypothesize the potential role of DPP-4 inhibitors, a novel class of antidiabetic drugs in increasing the number of circulating endothelial progenitor cells. Speculated mechanisms include several substrates for DPP-4 inhibitors: GLP-1, SDF-1α, substance P, and PACAP. As DPP-4 inhibitors show favorable safety profiles and do not cause hypoglycemia, they seem to be an attractive treatment option, at least in diabetic patients, and could become a part of vascular regenerative pharmacotherapy, ameliorating also symptoms related to erectile dysfunction. Since erectile dysfunction may precede other cardiovascular vascular events, because the penile arteries are smaller in size and therefore more susceptible to decreased nitric oxide production, treating this condition with an agent affecting positively also other blood vessels could help in preventing other cardiovascular events, including myocardial infarction and stroke. However, caution is required, because DPP-4 inhibitors are a heterogenous class of drugs, with variations regarding strength and duration of action, as well as selectivity and cardiovascular safety profile, which may affect properties other than those important in glucocontrol.

A comprehensive review of urologic complications in patients with diabetes

Diabetes Mellitus (DM) is a chronic disease characterized by hyperglycemia, as a result of abnormal insulin production, insulin function, or both. DM is associated with systemic complications, such as infections, neuropathy and angiopathy, which involve the genitourinary tract. The three most significant urologic complications include: bladder cystopathy, sexual dysfunction and urinary tract infections. Almost half of the patients with DM have bladder dysfunction or cystopathy, which can be manifested in women as hypersensitivity (in 39-61% of the diabetic women) or neurogenic bladder. In males it can be experienced as lower urinary tract symptoms (in 25% of diabetic males with a nearly twofold increased risk when seen by age groups). Additionally, an increased prostate volume affects their micturition as well as their urinary tract. Involving sexual dysfunction in women, it includes reduced libido, decreased arousal, clitoral erectile dysfunction and painful or non-sensitive intercourse; and in diabetic males it varies from low libido, ejaculatory abnormalities and erectile dysfunction. Globally, sexual disorders have a prevalence of 18-42%. Erectile dysfunction is ranked as the third most important complication of DM. Urinary tract infections are observed frequently in diabetic patients, and vary from emphysematous infections, Fournier gangrene, staghorn infected lithiasis to repetitive bacterial cystitis. The most frequent finding in diabetic women has been lower urinary tract infections. Because of the high incidence of obesity worldwide and its association with diabetes, it is very important to keep in mind the urologic complication associated with DM in patients, in order to better diagnose and treat this population.

Black tea extract and its thearubigins relieve the sildenafil-induced delayed gut motility in mice: a possible role of nitric oxide

In this study we hypothesize that a standardized black tea aqueous extract (BTE) and thearubigins, its main polyphenolic pigments, will improve sildenafil-induced delay in gastric emptying (GE) and small intestinal transit (SIT) in mice. Twenty groups of mice (n = 8) were given a phenol red meal, and three sets of experiments were performed. In the first and second sets, effects of different concentrations of BTE, thearubigins (TRs), and sildenafil (SLD), alone and in combinations, on GE and SIT were measured. In the third set, influence of nω -Nitro-l-arginine methyl ester hydrochloride (l-NAME) pretreatment on effects of these treatments was tested. Black tea extract (3% and 4.5%) and thearubigins (50 and 60 mg/kg) dose-dependently increased GE and SIT, whereas BTE 6% and thearubigins 70 mg/kg did not affect them. Sildenafil dose-dependently reduced both GE and SIT. Combination of metoclopramide, BTE 4.5%, thearubigins 60, or l-NAME with sildenafil (5 mg/kg) reversed its motility-delaying effects. Pretreatment with l-NAME followed by BTE 4.5%, thearubigins 60, BTE 4.5% + sildenafil 5, or thearubigins 60 + sildenafil 5 only partially affected the accelerating effects of BTE 4.5% and thearubigins 60. In conclusion, a standardized BTE and its thearubigins improve the sildenafil-induced delayed gut motility in mice. This improvement was partially blocked by l-NAME suggesting a possible role of nitric oxide. Thus, BTE 4.5% or TRs 60 mg/kg solution could be considered a reliever therapy for the sildenafil-induced dyspepsia.

Prevalence of erectile dysfunction and associated factors among diabetic men attending diabetic clinic at Muhimbili National Hospital in Dar-es-Salaam, Tanzania

INTRODUCTION

There has been an increase in the prevalence of erectile dysfunction (ED) in the general population especially among Diabetic patients. This seems to be neglected problem in low-income countries. This study aims at establishing the prevalence of ED and associated risk factors in diabetic patients attended at Diabetic Clinic at Muhimbili National Hospital.

METHODS

A cross-sectional hospital based study was conducted among 312 diabetic patients attending diabetic clinic at Muhimbili National Hospital between May and December 2011.

RESULTS

More than half (55.1%) of the patients were found to have some form of ED (12.8% had mild dysfunction, 11.5% moderate and 27.9% severe dysfunction). The severity of ED was correlated with increased age. Multivariate logistic regression revealed that ED was significantly predicted by old age (odds ratio (OR) = 7.1, 95% CI 1.2-40.7), evidence of peripheral neuropathy (OR) =5.9, 95% CI 1.6-21.3), and evidence of peripheral vascular disease (OR =2.5, 95% CI 1.2-5.3). Also longer duration of DM was marginally associated with ED (p=0.056). Patients with ED were also more likely to suffer other sexual domains (p<0.001). No lifestyle factor was associated with ED.

CONCLUSION

The prevalence of ED is high among DM patients. Interventions aimed at prevention, early diagnosis and detection of DM and its complications, and adherence to treatment to prevent complications should be implemented. Further studies should emphasize on temporal variation to show true causality of DM on erectile dysfunction.

Sexual dysfunction in diabetes

We aimed to summarize the etiology, clinical characteristics, diagnosis, and possible treatment options of sexual dysfunction in diabetic patients of both sexes. Details of dysfunction in diabetic women are less conclusive than in men due to the lack of standardized evaluation of sexual function in women. Male sexual dysfunction is a common complication of diabetes, including abnormalities of orgasmic/ejaculatory function and desire/libido in addition to penile erection. The prevalence of erectile dysfunction (ED) among diabetic men varies from 35% to 75%. Diabetes-induced ED has a multifactorial etiology including metabolic, neurologic, vascular, hormonal, and psychological components. ED should be regarded as the first sign of cardiovascular disease because it can be present before development of symptomatic coronary artery disease, as larger coronary vessels better tolerate the same amount of plaque compared to smaller penile arteries. The diagnosis of ED is based on validated questionnaires and determination of functional and organic abnormalities. First-, second- and third-line therapy may be applied. Phosphodiesterase-5 (PDE-5) inhibitor treatment from the first-line options leads to smooth muscle relaxation in the corpus cavernosum and enhancement in blood flow, resulting in erection during sexual stimulus. The use of PDE-5 inhibitors in the presence of oral nitrates is strictly contraindicated in diabetic men, as in nondiabetic subjects. All PDE-5 inhibitors have been evaluated for ED in diabetic patients with convincing efficacy data. Second-line therapy includes intracavernosal, trans- or intraurethral administration of vasoactive drugs or application of a vacuum device. Third-line therapies are the implantation of penile prosthesis and penile revascularization.

An update on pharmacological treatment of erectile dysfunction with phosphodiesterase type 5 inhibitors

INTRODUCTION

Phosphodiesterase type 5 inhibitors (PDE5-i) are used for the oral treatment of erectile dysfunction (ED). Since the launch of sildenafil more than 15 years ago, new molecules have become available. At present, in addition to tadalafil and vardenafil, there are three other drugs, udenafil, avanafil and mirodenafil, marketed in some countries which appear to be promising.

AREAS COVERED

The clinical pharmacological differences in dosage and side effects of all PDE5-i are evaluated.

EXPERT OPINION

All PDE5-i are equally effective and safe for the treatment of ED. On-demand use of any PDE5-i is also safe for patients with comorbid conditions. Tadalafil seems to be the preferred drug by patients and physicians, probably due to its peculiar pharmacological profile that makes sexual intercourse more spontaneous for the patients. Preliminary data suggest that the use of vardenafil may also be beneficial in cases of ED associated with premature ejaculation. Daily treatment is another option in men with ED and documented vascular or prostate disease. In geriatric or in difficult-to-treat populations, the evaluation of testosterone plasma levels will help to predict the efficacy of any PDE5-i. Remarkably, when such drugs are withdrawn for any reason, ED most often continues to occur because of the presence of an underlying disease.

National recommendations: Psychosocial management of diabetes in India

Although several evidence-based guidelines for managing diabetes are available, few, if any, focus on the psychosocial aspects of this challenging condition. It is increasingly evident that psychosocial treatment is integral to a holistic approach of managing diabetes; it forms the key to realizing appropriate biomedical outcomes. Dearth of attention is as much due to lack of awareness as due to lack of guidelines. This lacuna results in diversity among the standards of clinical practice, which, in India, is also due to the size and complexity of psychosocial care itself. This article aims to highlight evidence- and experience-based Indian guidelines for the psychosocial management of diabetes. A systemic literature was conducted for peer-reviewed studies and publications covering psychosocial aspects in diabetes. Recommendations are classified into three domains: General, psychological and social, and graded by the weight they should have in clinical practice and by the degree of support from the literature. Ninety-four recommendations of varying strength are made to help professionals identify the psychosocial interventions needed to support patients and their families and explore their role in devising support strategies. They also aid in developing core skills needed for effective diabetes management. These recommendations provide practical guidelines to fulfill unmet needs in diabetes management, and help achieve a qualitative improvement in the way physicians manage patients. The guidelines, while maintaining an India-specific character, have global relevance, which is bound to grow as the diabetes pandemic throws up new challenges.

Avanafil for the treatment of erectile dysfunction: a multicenter, randomized, double-blind study in men with diabetes mellitus

OBJECTIVE

To prospectively assess the safety and effectiveness of the investigational phosphodiesterase 5 inhibitor avanafil to treat erectile dysfunction in men with diabetes mellitus.

PATIENTS AND METHODS

This 12-week, multicenter, double-blind, placebo-controlled study conducted between December 15, 2008, and February 11, 2010, randomized 390 men with diabetes and erectile dysfunction 1:1:1 to receive avanafil, 100 mg (n=129), avanafil, 200 mg (n=131), or placebo (n=130). Coprimary end points assessed changes in the percentage of sexual attempts in which men were able to maintain an erection of sufficient duration to have successful intercourse (Sexual Encounter Profile [SEP] 3), percentage of sexual attempts in which men were able to insert the penis into the partner's vagina (SEP 2), and International Index of Erectile Function erectile function domain score.

RESULTS

Compared with placebo, least-squares mean change from baseline to study end in SEP 3, SEP 2, and International Index of Erectile Function erectile function domain score were significantly improved with both avanafil, 100 mg (P≤.002), and avanafil, 200 mg (P<.001). Additional analyses indicated that successful intercourse could be initiated in 15 minutes or less through more than 6 hours after avanafil dosing. Adverse events most commonly reported with avanafil treatment were headache, nasopharyngitis, flushing, and sinus congestion.

CONCLUSION

Avanafil was safe and effective for treating erectile dysfunction in men with diabetes and was effective as early as 15 minutes and more than 6 hours after dosing. The adverse events seen with avanafil were similar to those seen with other phosphodiesterase 5 inhibitors.

TRIAL REGISTRATION

clinicaltrials.gov Identifier NCT00809471.

Poly(ADP-ribose) polymerase inhibition improves erectile function by activation of nitric oxide/cyclic guanosine monophosphate pathway in diabetic rats

INTRODUCTION

Endothelial dysfunction-induced abnormalities of the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) signaling pathway in the corpus cavernosum are thought to be the main factors involved in the pathogenesis of diabetes-induced erectile dysfunction (ED). Recent studies have shown that the poly(adenosine diphosphate ribose) polymerase (PARP) pathway plays a critical role in diabetic endothelial dysfunction.

AIM

  The aim of this study is to determine whether activation of the PARP pathway is involved in diabetic cavernosal endothelial dysfunction and abnormalities of the NO/cGMP pathway.

METHODS

Male Sprague-Dawley rats were randomly divided into three groups: age-matched controls, diabetic controls (DM), and the 3-aminobenzamide (3-AB, a PARP inhibitor)-treated diabetic group (DM+3-AB). Diabetes was induced by intraperitoneal injection of streptozotocin. Eight weeks after inducing diabetes, the DM+3-AB group was treated with 3-AB for 4 weeks.

MAIN OUTCOME MEASURES

Erectile function was assessed at 12 weeks after inducing diabetes by stimulating the cavernous nerve. Expression of poly(ADP-ribose), protein kinase B (Akt), phospho-Akt, endothelial nitric oxide synthase (eNOS), phospho-eNOS, and neuronal nitric oxide synthase (nNOS) were evaluated by Western blot. Cavernous NO generation and cGMP levels were also determined.

RESULTS

The DM group showed impaired erectile function and significantly increased PARP activity. Expression of total eNOS and nNOS, phospho-Akt, and eNOS decreased significantly in the DM group compared with those in the control group. In addition, cavernous NO generation and cGMP levels decreased significantly in the DM group compared with those in the control group. Treatment with 3-AB restored erectile function and significantly reversed all molecular alterations except decreased nNOS expression.

CONCLUSION

Overactivation of the PARP pathway in the corpus cavernosum of diabetic rats was involved in cavernosal endothelial dysfunction and abnormalities of the NO/cGMP pathway resulting in ED. These findings may be applied to develop novel therapies for patients with diabetic ED.

Healthy coping: issues and implications in diabetes education and care

Psychological, emotional, and social factors not only impact quality of life, but also often play a role in chronic illness outcomes. Diabetes care, in particular, is greatly influenced by psychosocial factors when they hinder a person's ability to manage the disease and achieve metabolic control. Healthy coping, defined as responding to a psychological and physical challenge by recruiting available resources to increase the probability of favorable outcomes in the future, is essential to effective self-management by people with diabetes. In June 2009, the American Association of Diabetes Educators convened a multidisciplinary expert panel to discuss healthy coping in diabetes. The panel included diabetes educators and behavioral science and mental health professionals. Drawing on their knowledge and experiences, as well as information presented at the symposium, the panel probed several aspects of healthy coping including what it entails, common barriers, assessment, population diversity, and clinical applications. A team approach to addressing the patient's coping is critical. Team involvement relieves the diabetes educator of the entire burden of supporting the patient in this regard. The team should be broadly defined and include those who are formally and informally involved. Healthy coping is a complex, qualitative behavior that cannot be easily quantified. Future efforts to address the issue of healthy coping should add to the body of literature regarding diabetes self-management at the individual and population-based levels.

[Sexual dysfunction in the elderly. Pathophysiological and medical issues. Treatment of erectile dysfunction]

Erectile dysfunction (ED) is a very distressing condition that not only negatively affects the elderly man's sexual ability, but also his overall quality of life and that of his partner. Encouraging men, alone or as a couple, to seek professional help is a major educational challenge which needs to be met by medical, social and political initiatives. The exact pathogenesis of ED remains unknown, but is presumed to be multifactorial; vascular disease is the most frequent cause with endothelial dysfunction being the common denominator. It has been postulated that ED is a sentinel symptom of cardiovascular clinical events and should prompt investigation and intervention for cardiovascular risk factors. Therefore, when a patient presents with ED, a thorough history and physical examination should be performed, as well as appropriate laboratory tests aimed at detecting associated diseases.

A multicenter, randomized, open-labeled, parallel group trial of sildenafil in alcohol-associated erectile dysfunction: the impact on psychosocial outcomes

To examine the effect of sildenafil on erectile dysfunction (ED) and psychosocial outcomes in alcohol-dependent (AD) men, 108 men with these diagnoses were randomly assigned to either take sildenafil (50 mg) as add-on to standard treatment for AD, or the same treatment without sildenafil, for 12 weeks. Only 50 patients in sildenafil group and 51 in control group twice completed the International Index of Erectile Function (IIEF) and a battery of self-report questionnaires. IIEF scores and psychosocial functioning, self-esteem and support from friends improved only for sildenafil-treated patients (P < 0.001). The high effect sizes suggest that the observed benefits are unlikely to be a placebo effect, although their unspecific nature could not be ruled out. In men with ED associated with AD, sildenafil improves both ED and psychosocial outcomes. Further placebo-controlled clinical trial is warranted.

Type 1 and Type 2 diabetic-erectile dysfunction: same diagnosis (ICD-9), different disease?

INTRODUCTION

Although hyperglycemia is a common defining feature of both type 1 and type 2 diabetes, many unique characteristics distinguish these diseases, including insulin and lipid levels, obesity status, and inflammatory agent profiles. In the laboratory, the presence of erectile dysfunction (ED) has been established in animal models of both type 1 and type 2 diabetes.

AIM

The purpose of this study was to determine whether unique mechanisms underlie ED in type 1 vs. type 2 diabetic animal models.

MAIN OUTCOME MEASURES

Many mechanisms can underlie ED, including impaired dilatory signaling, heightened contractile sensitivity, and veno-occlusive disorder.

METHODS

Using PubMed, the literature was mined to evaluate what is known about which mechanism underlie ED in type 1 vs. type 2 diabetic animal models.

RESULTS

Impaired cavernosal vasodilation has been established in type 1 diabetic rodents. This dysfunction appears to be mediated by a severe defect in non-adrenergic-non-cholinergic nerve signaling, as well as impairment in penile endothelial function. In contrast, type 2 diabetic animals appear to have minimal impairment in parasympathetic-mediated dilatory function, but do have evidence of endothelial dysfunction. Type 2 diabetic models also exhibit a significant and striking increase in cavernosal contractile sensitivity, and a significant veno-occlusive disorder, neither of which is consistently reported in type 1 diabetic animals.

CONCLUSIONS

With the distinct mechanisms underlying the ED phenotype in animal models of type 1 and type 2 diabetes, tailoring therapeutic treatments for diabetic-ED to the specific mechanisms underlying this disease complication may be warranted. Further examination of mechanisms underlying ED in diabetic human patients may thus lead to significant changes in the way urologists diagnose, code, and treat diabetic-ED.

You'll "get viagraed:" Mexican men's preference for alternative erectile dysfunction treatment

The pharmaceutically focused clinical and epidemiological literature on erectile dysfunction (ED) treatment has paid little attention to men's non-medical responses to changing erectile function. This study explores the relationship of erectile function change, resulting use of medical or alternative treatments, and Mexican men's understandings of masculinity and aging, through a mixed method approach utilizing both quantitative survey and ethnographic interview data. A survey of 750 men undertaken at the Instituto Méxicano del Seguro Social hospital in Cuernavaca, Mexico in April to June 2008 showed that only about half of those who experienced erectile function changes sought treatment for these changes; treatment users were far more likely to seek alternative treatment than medical treatment, especially preferring lifestyle change and vitamins. Ethnographic data from interviews with 250 male urology patients undertaken from October 2007 to August 2008 at the same site reveal that treatment users' preferences were linked to fears about the safety and situational inappropriateness of medical ED treatment. These findings suggest that by focusing on patients' use of pharmaceuticals, biomedically oriented research has overlooked the most common responses to changing erectile function. Broadening the focus of ED treatment research to include analysis of men's rejection of pharmaceutical treatment - either in favor of alternative treatment, or because they do not see their erectile function changes as requiring medical intervention - would correct this imbalance in the literature. Further, the knowledge that even men who seek treatment may prefer alternatives to pharmaceutical interventions will help physicians to offer treatments, such as lifestyle change, that their patients might find more acceptable. Such measures would simultaneously help to mitigate the chronic illnesses, like diabetes and hypertension, which frequently co-occur with diminished erectile function.

Gene therapy via inducible nitric oxide synthase: a tool for the treatment of a diverse range of pathological conditions

Nitric oxide (NO(.)) is a reactive nitrogen radical produced by the NO synthase (NOS) enzymes; it affects a plethora of downstream physiological and pathological processes. The past two decades have seen an explosion in the understanding of the role of NO(.) biology, highlighting various protective and damaging modes of action. Much of the controversy surrounding the role of NO(.) relates to the differing concentrations generated by the three isoforms of NOS. Both calcium-dependent isoforms of the enzyme (endothelial and neuronal NOS) generate low-nanomolar/picomolar concentrations of NO(.). By contrast, the calcium-independent isoform (inducible NOS (iNOS)) generates high concentrations of NO(.), 2-3 orders of magnitude greater. This review summarizes the current literature in relation to iNOS gene therapy for the therapeutic benefit of various pathological conditions, including various states of vascular disease, wound healing, erectile dysfunction, renal dysfunction and oncology. The available data provide convincing evidence that manipulation of endogenous NO(.) using iNOS gene therapy can provide the basis for future clinical trials.

Erectile dysfunction in the type II diabetic db/db mouse: impaired venoocclusion with altered cavernosal vasoreactivity and matrix

The number of men with type II diabetes-associated erectile dysfunction (ED) continues to grow rapidly; however, the majority of basic science studies has examined mechanisms of ED in animal models of type I diabetes. In this study, we first establish an in vivo mouse model of type II diabetic ED using the leptin receptor mutated db/ db and wild-type control BKS mouse. Furthermore, we hypothesized that dual mechanistic impairments contribute to the impaired erectile function in the type II diabetic mouse, altered vasoreactivity, and venoocclusive disorder. In vivo erectile function was measured as intracavernosal pressure (ICP) normalized to mean arterial pressure (MAP) following electrical stimulation of the cavernosal nerve. Venoocclusion was assessed by the maintenance of elevated in vivo ICP following intracorporal saline infusion. Vasoreactivity of isolated cavernosum in response to contractile and dilatory stimulation was examined in vitro by myography. Collagen and elastin content were evaluated by quantification of hydroxyproline and desmosine, respectively, as well as by quantitative PCR and histological analysis of isolated cavernosum. Erectile function was significantly decreased in db/ db vs. BKS mice in a manner consistent with impairments in venoocclusive ability and decreased inflow. Heightened vasoconstriction and attenuated dilation in cavernosum of db/ db vs. BKS mice suggest an overall lowered relaxation ability and thus impaired filling of the cavernosal spaces. A decrease in desmosine and hydroxyproline as well as lowered mRNA levels for tropoelastin, fibrillin-1, and α1(I) collagen were detected. These vasoreactive and sinusoidal matrix alterations may alter tissue compliance dispensability, preventing the normal expansion necessary for erection.

Combination of alfuzosin and tadalafil exerts in vitro an additive relaxant effect on human corpus cavernosum

INTRODUCTION

Phosphodiesterase type 5 (PDE5) inhibitors, such as tadalafil, are a first-line treatment for erectile dysfunction (ED). Nevertheless, some patients do not respond to this treatment. Clinical data suggest that the addition of alpha1-adrenoceptor blocker, such as alfuzosin, commonly prescribed for lower urinary tract symptoms suggestive of benign prostatic hyperplasia, may be of benefit. Aim. Evaluation of the effect of alfuzosin, tadalafil or the combination of both on human corpus cavernosum.

METHODS

Human cavernosal tissues were obtained from 10 patients undergoing penile surgery. Strips contractility was studied in organ baths. Concentration-response curves to tadalafil were generated on norepinephrine (NE, 1-10 microM)-precontracted strips in the presence of alfuzosin or vehicle. Frequency-response curves (FRC) to electrical field stimulation (EFS, 0-64 Hz, 3 ms, 10 seconds, 300 mA) were generated in the presence of vehicle, alfuzosin, tadalafil, or both drugs combined. EFS (20 Hz, 1 ms, 10 seconds, 300 mM)-induced nitrergic relaxation on NE-precontracted strips was studied in the presence of vehicle, alfuzosin, tadalafil, or both drugs combined.

MAIN OUTCOME MEASURES

Functional measurement of cavernosal smooth muscle relaxation in the presence of tadalafil and alfuzosin.

RESULTS

The relaxation induced by tadalafil (10(-10) to 10(-5) M) on precontracted strips was enhanced by alfuzosin at both 10(-8) and 10(-7) M. The combination of alfuzosin (3.10(-8) M) and tadalafil (10(-7) M) was more efficient to inhibit FRC-induced contractions than each compound alone. The combination of tadalafil (10(-6) M) and alfuzosin (10(-8) M) increased the relaxation induced by EFS and its effect was greater than tadalafil alone. In addition, the combination of tadalafil (10(-6) M) and alfuzosin (10(-7) M) prolonged EFS-induced relaxation to a greater extent than each compound alone.

CONCLUSIONS

In vitro, the combination of alfuzosin and tadalafil is more efficient than each compound alone to relax adrenergic tone or to enhance nitrergic relaxation of the human corpus cavernosum. Such a combination deserves further investigation in placebo-controlled studies to evaluate its benefit in ED patients who are not sufficiently improved by PDE5 inhibitors.

Improvement of vascular function by acute and chronic treatment with the PDE-5 inhibitor sildenafil in experimental diabetes mellitus

BACKGROUND AND PURPOSE

Diabetes-associated vascular dysfunction contributes to increased cardiovascular risk. We investigated whether the phosphodiesterase-5 inhibitor sildenafil would improve vascular function in diabetic rats.

EXPERIMENTAL APPROACH

Male Wistar rats were injected with streptozotocin (50 mg kg(-1), i.v.) to induce insulin-deficient diabetes. Direct effects of sildenafil as well as modification of endothelium-dependent and -independent vasorelaxation were investigated in vitro. The effects of acute and chronic (2 week) treatment in vivo of sildenafil on vascular function were also characterized in isolated aortic segments in organ bath chambers 4 weeks after diabetes induction.

KEY RESULTS

Sildenafil induced a concentration-dependent vasorelaxation, which was attenuated by the nitric oxide (NO) synthase inhibitor, N(G)-nitro-L-arginine. Acetylcholine-induced endothelium-dependent as well as endothelium-independent relaxation induced by the NO donor, DEA-NONOate, was significantly reduced in aortae from diabetic rats. Incubation with sildenafil in vitro normalized both endothelium-dependent and -independent relaxation in aortae from diabetic rats. Acute as well as chronic in vivo treatment with sildenafil resulted in enhanced endothelium-dependent and -independent vasorelaxation. Superoxide formation was increased in diabetes, associated with enhanced membrane expression of the NAD(P)H oxidase subunit gp91(phox) and Rac, which were both reduced by chronic treatment with sildenafil.

CONCLUSIONS AND IMPLICATIONS

We demonstrate that sildenafil treatment rapidly and chronically improves vascular relaxation in diabetic rats. Treatment with sildenafil might provide a similarly beneficial effect in diabetic patients.

Diabetes and sexual dysfunction: results from the Olmsted County study of urinary symptoms and health status among men

PURPOSE

We examined the association of diabetes and domains of sexual dysfunction in a population based sample of men residing in Olmsted County, Minnesota.

MATERIALS AND METHODS

A cohort of 2,115 white men 40 to 79 years old as of January 1, 1990 was randomly selected from the Olmsted County population. Men who had a history of prostate or bladder surgery, urethral surgery or stricture, or medical or other neurological condition that could affect normal urinary function were excluded from analysis. Diabetes itself was not used as an exclusionary criterion, although those with end stage organ failure as a result of diabetes were excluded. A previously validated male sexual function index was included in the questionnaires administrated to the cohort in 1996, which consisted of 11 questions on the 5 sexual function domains of sexual drive, erectile function, ejaculatory function, sexual problem assessment and sexual satisfaction. The baseline questionnaire also included whether they had ever been diagnosed by a physician as having diabetes. Only men with regular sexual partners were included.

RESULTS

Individuals with diabetes at baseline had significantly greater dysfunction in all 5 sexual function domains. In multivariate adjusted analyses diabetes was significantly associated with all sexual dysfunction domains. The associations remained significant after adjusting for numerous predictors of sexual dysfunction.

CONCLUSIONS

The presence of diabetes at baseline was significantly associated not only with erectile dysfunction but with all aspects of sexual dysfunction, including sexual drive, ejaculatory function, sexual problems and sexual satisfaction in this population based sample of men residing in Olmsted County.

Efficacy and safety of flexible-dose vardenafil in men with type 1 diabetes and erectile dysfunction

INTRODUCTION

Erectile dysfunction (ED) affects up to 70% of men with diabetes, occurring with a higher prevalence in those with type 1 diabetes than with type 2 diabetes. Studies investigating treatment of ED in men with diabetes have largely been conducted in a total male population with diabetes. Limited data are available on the efficacy and safety of the potent oral phosphodiesterase-5 inhibitor vardenafil in men with ED and type 1 diabetes.

AIMS

To evaluate the safety and efficacy of flexible-dose vardenafil therapy in a prospective randomized study in phosphodiesterase 5 inhibitor-naïve subjects with type 1 diabetes and ED.

METHODS

In this multicenter, double-blind, placebo-controlled clinical trial, phosphodiesterase-5 inhibitor-naïve patients were randomized to receive placebo (N = 149) or flexible-dose (5-20 mg) (N = 153) vardenafil.

MAIN OUTCOME MEASURE

Sexual Encounter Profile diary questions 2 and 3, concerning success rates of vaginal insertion and maintenance of erection to allow successful intercourse, respectively.

RESULTS

Vardenafil significantly improved mean success rates for Sexual Encounter Profile 2 and 3 compared with baseline and placebo at 4, 8, and 12 weeks (P < 0.0001, intention to treat and last observation carried forward). These rates were unaffected by stratification into distinct subsets according to the level of HbA(1c) (HbA(1c) < 7%, good glycemic control; HbA(1c) >7- < or = 8%, moderate glycemic control; and HbA(1c) > 8%, poor glycemic control). Vardenafil treatment also significantly improved the Erectile Function domain score (P < 0.0001) of the International Index of Erectile Function compared with placebo, in addition to scores for the other individual domains of the International Index of Erectile Function. The most commonly reported treatment-emergent adverse events were headache (3.1%) and flushing (2.5%), which were mild to moderate and transient in nature.

CONCLUSION

These data suggest that vardenafil significantly improves erectile function in men with type 1 diabetes and is well tolerated, regardless of the level of glycemic control.

Diabetic neuropathies: diagnosis and treatment

Diabetic neuropathy can affect every organ system of the body. Diagnosis of diabetic neuropathy is usually one of exclusion. Clinical guidelines and the introduction of new medications for pain relief in peripheral neuropathy are improving medical and nursing management. Simpler diagnostic tests for cardiac autonomic neuropathy, which can be performed in an office setting, may mean earlier recognition and treatment with less mortality. Oral medications for the treatment of erectile dysfunction make it easier for the patient to seek treatment for a condition that impact quality of life.

Phosphodiesterase type 5 inhibitors: the day after

OBJECTIVE

Review the literature on phosphodiesterase type 5 inhibitors (PDE5-Is), addressing critical issues in their current and future use, assessing unanswered questions, and identifying research needs.

METHODS

A MEDLINE search was conducted on PDE5-Is, with emphasis on clinical trials and experience, for interpretation and analysis of their present and future role.

RESULTS

Although approximately 40 million patients with erectile dysfunction have been treated successfully worldwide with the three available PDE5-Is, inappropriate instructions, lack of follow-up, and lack of patient-centered care models are the main reasons for "non-response," leading to drop-out rates of >50%. Patients with severe neurologic damage, diabetes mellitus, or severe vascular disease may be resistant to PDE5-Is. Preservation of corporal smooth muscle with chronic administration of PDE5-Is has been reported and substantial evidence indicates that these drugs have beneficial effects on endothelium and cardiovascular function; sildenafil has been approved for the treatment of idiopathic pulmonary hypertension. Improvement of lower urinary tract symptoms in men with benign prostatic hyperplasia after PDE5-I administration has been also suggested.

CONCLUSIONS

The data indicate the necessity for (1) exploration of the pharmacologic characteristics of the three PDE5-Is; (2) research on their pharmacologic differences because some actions seems to be drug-specific; (3) development of alternative management strategies, such as chronic, low, everyday doses of PDE5-Is, if the monthly cost is affordable; and (4) clinical trials on use of PDE5-Is to treat other chronic conditions. The door for innovative therapeutic approaches will open, specifically for cross-risk factor treatment with PDE5-Is or their use in combination treatments or new multimodal pills that take advantage of drugs that exert pleiotropic vascular actions.

Sildenafil improves sexual functioning in premenopausal women with type 1 diabetes who are affected by sexual arousal disorder: a double-blind, crossover, placebo-controlled pilot study

OBJECTIVE

To verify whether sildenafil is effective in type 1 premenopausal women affected by sexual arousal disorder (SAD).

DESIGN

Double-blind, crossover, placebo-controlled study.

SETTING

Gynecological diabetic outpatient clinic and sexual clinic.

PATIENT(S)

Thirty-six type 1 premenopausal diabetic women affected by SAD.

INTERVENTION(S)

Two 8-week periods of sildenafil 100 mg, washout, and placebo, by two possible sequences.

MAIN OUTCOMES MEASURE(S)

Each woman submitted blood samples to measure HbA(1c), and T, free T (FT), and PRL. Efficacy was assessed [1] subjectively by the Personal Experiences Questionnaire based on the 5-point Likert scale, quantifying arousal, desire, orgasm, enjoyment of sexual activities, and frequency of sexual relationships; and [2] objectively by translabial color Doppler ultrasound to measure the resistance index (RI), pulsatility index (PI), peak systolic velocity (PSV), and end diastolic velocity of clitoral arteries.

RESULT(S)

Thirty-two women completed the study. The mean HbA(1c) value was 8.0% +/- 1.8%, and plasma concentrations of T, FT, and PRL were normal. Sildenafil seems to improve arousal, orgasm and sexual enjoyment, and dyspareunia in women affected by type 1 diabetes. However, by flowmetric measurements, the mean RI was significantly lower and both the mean PI and PSV of the clitoral arteries were significantly higher compared with baseline and placebo.

CONCLUSION(S)

Sildenafil seems to improve subjective sexual aspects and can be used to treat objectively genital arousal disorder of premenopausal women with type 1 diabetes.

Impairment of endothelium- and nerve-mediated relaxation responses in the cavernosal smooth muscle of experimentally diabetic rabbits: role of weight loss and duration of diabetes

The effects of short- and long-term experimental diabetes on corporal nerve, endothelium and smooth-muscle responses were investigated, and the reasons for possible alterations in corporal smooth muscle responses such as hyperglycaemia, duration of experimental diabetes and/or altered tissue weight were evaluated. Rabbits were injected with alloxan (125 mg/kg) to induce diabetes. Age-matched non-diabetic and diabetic (3 and 9 weeks) and weight-matched non-diabetic groups (9 weeks) were used as control. In all groups, relaxation (carbachol, electrical field stimulation and sodiumnitroprusside) responses were examined. The relaxation responses were expressed as percentage of the precontraction to phenylephrine and as g response/g tissue weight. The effects of elevated glucose were also examined by incubating cavernosal strips in Krebs-Henseleit solution containing 44.4 mM glucose for 6 h. Cavernosal tissues of non-diabetic and 9-week diabetic rabbits were evaluated histologically. Sodiumnitroprusside (10(-7)-10(-4) M) responses were similar in all groups. Relaxation responses to electrical field stimulation (10 s train; amplitude 50 V; frequency 0.5-32 Hz; width 0.8 ms) were only attenuated in the 9-week diabetic group compared to the non-diabetic group. Carbachol (10(-8)-3 x 10(-5) M) responses were attenuated in both diabetic groups. When the relaxation responses expressed as g response/g tissue weight were evaluated, results were similar compared to those expressed as percentage of phenylephrine (10(-5) M). Neither carbachol nor electrical field stimulation mediated responses were impaired with glucose incubation. No morphological degenerations were observed in the endothelium. Diabetes may interfere with the synthesis and/or release of nitric oxide from both nerves and endothelium in corpus cavernosum, and alterations in endothelium-derived responses occur earlier than neurological disturbances. The sensitivity of cavernosal smooth muscle to nitric oxide did not alter in diabetes. Attenuation of responses was not due to decreased tissue weight caused by diabetes.