Erectile potentials of a new phosphodiesterase type 5 inhibitor, DA-8159, in diet-induced obese rats

Aim： To examine the changes in the erectile function in diet-induced obese rats and investigate the oral efficacy of DA-8159, a new phosphodiesterase type 5 （PDE5） inhibitor, on penile erection in obese rats. Methods： The rats were fed a high-energy diet for 12 weeks and divided into three groups： an obesity-resistant （OR） control group, an obesity-prone （OP） control group, and an OP-DA-8159 treatment （DA-8159） group. The electrostimulation-induced erectile responses were measured in all groups. The body weight, plasma cholesterol, triglyceride and glucose levels were also measured. Results： In the OP control group, the maximum intracavernous pressure （ICP） and ICP/blood pressure （ICP/BP） ratio after electric stimulation were significantly lower than those in OR control group. The corresponding area under the curve （AUC） of the ICP/BP ratio, the detumescence time and the baseline cavernous pressure were also lower than those in the OR control group, but this difference was not significant. The body weight gain, plasma cholesterol and triglyceride level in the OP group were significantly higher than those in the OR group. After administering the DA-8159, a significant increase in the maximum ICP and the ICP/BP ratio were observed. The corresponding AUCs in the DA-8159 group were also higher than those in the two control groups. Furthermore, the detumescence time was significantly prolonged after treatment with DA-8159. Conclusion： These results demon- strate that diet-induced obesity affects the erectile function in rats and these erectile dysfunction （ED） can be improved by the treatment with DA-8159, indicating DA-8159 might be a treatment option for ED associated with obesity.

Evaluation and diagnostic testing of erectile dysfunction in the era of phosphodiesterase type 5 inhibitors

The diagnosis and treatment of erectile dysfunction has changed dramatically since the availability of safe and effective oral therapies. Unfortunately, not all men can be adequately treated in this way, and might require more invasive testing to diagnose and treat the specific cause of their dysfunction. This review looks at the tests and strategies available for men who cannot be treated by oral therapy alone.

Erectile potentials of a new phosphodiesterase type 5 inhibitor,DA-8159,in diet-induced obese rats

Aim:To examine the changes in the erectile function in diet-induced obese rats and investigate the oral efficacy of DA-8159,a new phosphodiesterase type 5(PDE5)inhibitor,on penile erection in obese rats.Methods:The rats were fed a high-energy diet for 12 weeks and divided into three groups:an obesity-resistant(OR)control group,an obesity- prone(OP)control group,and an OP-DA-8159 treatment(DA-8159)group.The electrostimulation-induced erectile responses were measured in all groups.The body weight,plasma cholesterol,triglyceride and glucose levels were also measured.Results:In the OP control group,the maximum intracavernous pressure(ICP)and ICP/blood pressure(ICP/BP)ratio after electric stimulation were significantly lower than those in OR control group.The corresponding area under the curve(AUC)of the ICP/BP ratio,the detumescence time and the baseline cavernous pressure were also lower than those in the OR control group,but this difference was not significant.The body weight gain,plasma cholesterol and triglyceride level in the OP group were significantly higher than those in the OR group. After administering the DA-8159,a significant increase in the maximum ICP and the ICP/BP ratio were observed.The coerrsponding AUCs in the DA-8159 group were also higher than those in the two control groups.Furthermore,the detumescence time was significantly prolonged after treatment with DA-8159.Conclusion:These results demon- strate that diet-induced obesity affects the erectile function in rats and these erectile dysfunction(ED)can be im- proved by the treatment with DA-8159,indicating DA-8159 might be a treatment option for ED associated with obesity.

Patterns of treatment with PDE5 inhibitors in the clinical practice in Italy： longitudinal data from the Erectile Dysfunction Observational Study

The Erectile Dysfunction Observational Study （EDOS） is a 6-months observational prospective multicentric study enrolling men with erectile dysfunction （ED） who asked, to be started on a treatment or to change a previous treatment. Aims of the study were to analyse the pattern of treatment and compare the efficacy of treatments used. Patients were enrolled during a normal hospital visit and were prescribed a treatment for ED. They were asked at baseline and after 3 and 6 months, to answer a set of questions from the International Index of Erectile Function, Erectile Dysfunction Inventory of Treatment Satisfaction （EDITS） and Short Form of the Psychological and Interpersonal Relationships Scale questionnaires （SF-PAIRS）. Clinicians were free to prescribe any therapy for ED available in the market, and to change therapy at any time during the study. Out of 1 338 patients, available for analysis at 6 months, 624 （47%） changed their treatment during the study and 714 （53%） continued with the drug prescribed at baseline. Patients assuming tadalafil had a significantly higher probability of maintaining the same treatment compared to sildenafil or vardenafil. There was no clinically significant difference in terms of efficacy, patient satisfaction, self-confidence and spontaneity between the different inhibitors of PDE5. The ‘time concerns＇ domain score of SF-PAIRS, was statistically better in patients assuming tadalafil. In conclusion sildenafil, vardenafil and tadalafil show similar efficacy in the clinical practice. However, patients receiving tadalafil display a lower risk to discontinue or change the treatment.

Effect of phosphodiesterase inhibitors in the bladder

Many aging men will experience lower urinary tract symptoms(LUTS).Phosphodiesterase type 5(PDE5)inhibitors have shown promise in treating LUTS in these patients.PDE5 inhibitors mediate their effects through several pathways including cAMP,NO/cGMP,Kchannel modulated pathways,and the L-cysteine/H2S pathway.PDE5 inhibitors exert their effect in muscle cells,nerve fibers,and interstitial cells(ICs).The use of PDE5 inhibitors led to improvement in LUTS.This included urodynamic parameters.PDE5 inhibitors may play a significant role in LUTS due to their effect on the bladder rather than the prostate.

Efficacy and safety of on demand tadalafil in the treatment of East and Southeast Asian men with erectile dysfunction:a randomized double-blind,parallel,placebo-controlled clinical study

Aim： To assess the efficacy and safety of tadalafil in comparison to a placebo, when taken on demand for 12 weeks by East/Southeast Asian men with erectile dysfunction （ED）, Methods： This multicenter, randomized, double-blind, parallel group, placebo-controlled study was conducted at 17 centers across East and Southeast Asia between August 2002 and February 2003. Men more than 18 years of age with mild to severe ED of various etiologies were randomized to receive a placebo or 20 mg of tadalafil taken as needed （maximum once daily）. Efficacy assessments included the International Index of Erectile Function, the Sexual Encounter Profile diary and Global Assessment Questions. Results： Tadalafil significantly improved erectile function as compared to the placebo （P 〈 0.001）. At the endpoint, the patients receiving 20 mg of tadalafil reported a greater mean per patient percentage of successful intercourse attempts （Sexual Encounter Profile question 3： 70.9% compared to 33.5% in the placebo） and a greater proportion of improved erections （Global Assessment Question： 86.2% compared to 30.1%）. Most （≥3%） treatment emergent adverse events were mild or moderate. The most common treatment emergent adverse events were headache, back pain, dizziness and dyspepsia. Conclusion： Tadalafil was an effective and well-tolerated treatment for ED in East and Southeast Asian men.

Recent insights into androgen action on the anatomical and physiological substrate of penile erection

Erectile response is centrally and peripherally regulated by androgens. The original insights into the mechanisms of action of androgens were that androgens particularly exert effects on libido and that erections in response to erotic stimuli were relatively androgen-independent. It was shown that sexual functions in men required androgen levels at the low end of reference values of testosterone. So it seemed that testosterone was not useful treatment for men with erectile difficulties, particularly following the advent of the phosphodiesterase type 5 （PDE5） inhibitors. However, approximately 50% of those treated with PDE5 inhibitors discontinue their treatment. A number of recent developments shed new light on testosterone treatment of erectile dysfunction （ED） in aging men. （1） A recent insight is that, in contrast to younger men, elderly men might require higher levels of testosterone for normal sexual functioning. （2） Several studies have indicated that PDE5 inhibitors are not always sufficient to restore erectile potency in men, and that testosterone improves the therapeutical response to PDE5 inhibitors considerably. （3） There is growing insight that testosterone has profound effects on tissues of the penis involved in the mechanism of erection and that testosterone deficiency impairs the anatomical and physiological substrate of erectile capacity, reversible upon androgen replacement. The synthesis of PDE5 is upregulated by androgens, and the arterial inflow into the penis is improved by giving androgen. The above invites a re-examination of the merits of giving testosterone to aging men with ED. The beneficial effects of PDE5 inhibitors may only be optimally expressed in a eugonadal environment. （Asian J Androl 2006 Jan; 8： 3-9）

Influence of erectile dysfunction course on its progress and efficacy of treatment with phosphodiesterase type 5 inhibitors

Background Erectile dysfunction （ED） is a common impairment among older men, and the prevalence rates increase sharply after age of 60 years. Most studies have focused on the prevalence rate or dangerouse factors. The aim of this study was to investigate the basic epidemiologic data about ED patients with different ED courses. The purpose of this researth was to understand the therapeutic effect of phosphodiesterase type 5 inhibitor （PDE5-1） and see how and why the ED course impact the progress of ED and the therapeutic effect of PDE5-1 treatment. Methods From June 2008 to June 2009, 4252 questionnaires （Quality of Erection Questionnaire, QEQ） were gathered from 46 centers by urology or andrology doctors all around China. Patients with ED （age 〉 20 years） filled in first half of the questionnaires when they came for the first time, and then completed the second half 4 weeks after PDE5-1 therapy. Results ED courses of most patients were less than 5 years （〈5 years, 74.0%; 5-10 years 20.8%; 〉10 years, 5.2%）. As ED course increasing, the incidence of the risk factors of ED, such as smoking, drinking, hypertension, diabetes, heart disease and hyperlipidemia also increase （P 〈0.01）. PDES-I was effective in improving the quality of sexual activities （P 〈0.01）. Administration of PDE5-1 improves satisfaction, enjoyment and frequency of sexual activities. The longer the ED course, the worse the therapeutic effect （〈5 years, 96.1%; 5-10 years, 94.9%; 〉10 years, 89.0%） （P 〈0.01）. Conclusions The ED course greatly affected the therapeutic effect of PDE5-1, the patients with ED should consult doctor at early stage of the disease. Admistration of PDE5-1 effectively improves the penile erection and the quality of sexual life of the patients hence should be considered as first-line medicine in the treatment of ED.

A meta-regression evaluating the effectiveness and prognostic factors of oral phosphodiesterase type 5 inhibitors for the treatment of erectile dysfunction

The effectiveness of phosphodiesterase type 5 inhibitors （PDE5-1s） for erectile dysfunction （ED） varies considerably among trials, but available studies investigating the factors that affect the effectiveness are few and findings are not consistent. A systematic search was performed in PubMed, Cochrane Library, and EMBASE to identify randomized controlled trials comparing PDE5-1s with placebo for the treatment of ED. The methodological quality of included studies was assessed by the Cochrane Collaboration＇s tool for assessing risk of bias. The associations between prespecified study-level factors and effectiveness were tested by a random effects meta-regression model. This study included 93 trials with 26 139 patients. When all PDE5-1s were grouped together, Caucasian ethnicity was associated with 15.636% （95% confidence interval [CI]： 0.858% to 32.579%） increase in risk ratio （RR） for Global Assessment Questionnaire question-1 （GAQ-1）, and 1.473 （95% CI： 0.406 to 2.338） score increase in mean difference （MD） for posttreatment International Index of Erectile Function-Erectile Function domain score （IIEF-EF）, compared to Asian ethnicity. A one-score increase in baseline IIEF-EF was associated with -5.635% （95% CI： -9.120% to -2.017%） reduction in RR for GAQ-1, and -0.229 （95% CI： -0.425 to -0.042） score decrease in MD for posttreatment IIEF-EF. In conclusion, PDE5-1s are more effective in Caucasians than Asians, and in patients with more severe ED.

A randomized clinical trial investigating treatment choice in Chinese men receiving sildenafil citrate and tadalafil for treating erectile dysfunction

Sildenafil and tadalafil are efficacious and well tolerated in Chinese men with erectile dysfunction （ED）. Recent study results indicate that men with ED in China who were naive to phosphodiesterase inhibitor type 5 （PDE5） therapy prefer tadalafil 20-mg （on-demand） versus sildenafil 100-mg （on-demand）. Differences in psychosocial outcomes may help to explain treatment preference in favor of tadalafih This open-label, randomized, crossover study compared psychosocial outcomes and drug attribute choices between tadalafil and sildenafil in Chinese men with ED na＇（ve to PDE5 inhibitor therapy. Eligible patients were randomized to sequential 20-mg tadalafU/lOO-mg sildenafil （n = 190） or 100-mg sildenafil/20-mg tadalafil （n = 193） for 8 weeks each and were asked which treatment they preferred to take for the 8-week extension phase. Psychosocial outcomes were assessed using the Psychological and Interpersonal Relationship Scale （PAIRS）, Drug Attributes Questionnaire （DRAQ）, and Sexual Life Quality Questionnaire （SLQQ）. When taking tadalafil versus sildenafil, men had a higher mean endpoint score on the PAIRS Spontaneity Domain （tadalafil = 2.86 vs sildenafil = 2.72; P 〈 0.001）, and a lower mean endpoint score on the Time Concerns Domain （tadalafil = 2.41 vs sildenafil = 2.55; P 〈 0.001）. A numerical increase in the Sexual Self-Confidence Domain was observed when taking tadalafil versus sildenafil （tadalafil -- 2.76 vs sildenafil = 2.72; P= 0.102）. The most frequently chosen drug attributes explaining treatment preference were able to get an erection long after having drug, and ability to get an erection every time. SLQQ results were comparable between treatment groups. These psychosocial outcomes may explain why more Chinese men preferred tadalafil versus sildenafil for the treatment of ED in this clinical trial.

Effects of obstructive sleep apnea and its treatment over the erectile function： a systematic review

Erectile dysfunction （ED） is considered a condition with a broad range of etiologies. Obstructive sleep apnea （OSA） syndrome is one of the lesser studied risk factors for ED. We intend to summarize the current evidence on the relationship between OSA and sexual impairment, focusing on the results in terms of erectile function of the different therapies offered to OSA patients. A systematic review was conducted, selecting articles related to the physiology of OSA and ED, and to the treatments of OSA syndrome and their reported outcomes in erectile and sexual function. Higher prevalences of ED in the OSA groups have been published. However, whether this effect on the erectile function occurs in the entire range of OSA severities remains unclear. Several hypotheses were proposed to explain the physiology of this association. Continuous Positive Airway Pressure as a treatment for OSA patients with ED has achieved a significative improvement in the sexual parameters in most of the studies. Phosphodiesterase type 5 inhibitors （iPDE5） on demand are useful as a treatment for ED in this subgroup of patients, with high satisfaction rates. The surgical treatment for the OSA evidenced benefits over the erectile function, and the effect on the sexual satisfaction of the therapy using Mandibular Advancement Devices is still undefined.