Efficacy and Safety of Sildenafil by Age in Men With Erectile Dysfunction

An overview of conventional and investigational phosphodiesterase 5 inhibitors for treating erectile dysfunction and other conditions

INTRODUCTION

There is a rising concern about developing innovative, efficacious PDE5I molecules that provide better safety, efficacy, and tolerability with less adverse effects. Innovative PDE5I with dual targets have also been defined in the literature. Additionally, some of PDE5I are able to selectively inhibit other enzymes such as histone deacetylase, acetylcholine esterase, and cyclooxygenase or act as nitric oxide donors. This review presents knowledge concerning the advanced trends and perspectives in using PDE5I in treatment of ED and other conditions.

AREAS COVERED

Pre-clinical and early clinical trials that investigated the safety, efficacy, and tolerability of novel PDE5I such as Udenafil, Mirodenafil, Lodenafil, Youkenafil, Celecoxib, and TPN729 in treatment of ED and other conditions.

EXPERT OPINION

Preclinical and limited early clinical studies of the new molecules of PDE5I have demonstrated encouraging results; however, safety, efficacy, and tolerability are still issues that necessitate further long-term multicenter clinical studies to ensure justification of their uses in treatment of ED and other conditions. Progress in molecular delivery techniques and tailored patient-specific management and additional therapeutic technology will dramatically improve care for ED and other conditions. The dream of ED and many other conditions becoming more effectively managed may be feasible in the near future.

Effect of Mirabegron in Men With Overactive Bladder and Erectile Dysfunction: A Prospective Observational Study

BACKGROUND

As it has been observed that the erect penis has been the epitome of virility for the male community for decades, it became necessary to search for alternative treatments for the cause. So, the study was performed to evaluate the potential impact of mirabegron in men with mild to moderate erectile dysfunction (ED) and overactive bladder (OAB).

METHODS

It was a prospective, observational study that was carried out at the Department of Urology at Rajendra Institute of Medical Sciences, Ranchi, for a duration of two years and included a total of two hundred fifty patients. The individuals included had a diagnosis of mild to moderate erectile dysfunction (ED) along with symptoms of OAB. The overactive bladder questionnaire (OAB-q) score and the International Index of Erectile Dysfunction-5 (IIEF-5) score were used, respectively, to measure the impact of mirabegron on ED and OAB. Then, the changes in ED and OAB were evaluated at two, four, eight, and 12 weeks.

RESULTS

Among the total 250 patients recruited, around 32.5% of them had mild ED, 17.5% were diagnosed with mild to moderate ED, and 50% suffered from moderate ED. The IIEF-5 scores improved by four points or more in 86.25%, 91.25%, and 71.25% of patients after four, eight, and 12 weeks, respectively. OAB-q scores were likewise shown to decline in the fourth (13.1 ± 4.3) and eighth (12.8 ± 4.2) weeks when compared to the baseline (17.4 ± 5.5). Also, adverse events reported did not hamper the progress of the study.

CONCLUSION

The study concluded that mirabegron has a beneficial impact on controlling OAB symptoms among men diagnosed with mild to moderate ED. The effects last for only eight weeks, and then they decline. Furthermore, mirabegron was well-tolerated among patients and had no safety concerns with its use.

Novel erectile analyses revealed augmentable penile Lyve-1, the lymphatic marker, expression

Purpose

The pathophysiology of penis extends to erectile dysfunction (ED) to conditions including sexually transmitted diseases (STDs) and cancer. To date, there has been little research evaluating vascular drainage from the penis. We aimed to evaluate penile blood flow in vivo and analyze its possible relationship with the lymphatic maker.

Materials and Methods

We established an in vivo system designed to assess the dynamic blood outflow from the corpus cavernosum (CC) by dye injection. To analyze lymphatic characteristics in the CC, the expression of Lyve-1, the key lymphatic endothelium marker, was examined by the in vitro system and lipopolysaccharide (LPS) injection to mimic the inflammatory conditions.

Results

A novel cavernography methods enable high-resolution morphological and functional blood drainage analysis. The expression of Lyve-1 was detected along the sinusoids. Furthermore, its prominent expression was also observed after penile LPS injection and in the erectile condition.

Conclusions

The current in vivo system will potentially contribute to the assessment of penile pathology from a novel viewpoint. In addition, current analyses revealed inducible Lyve-1 expression for LPS injection and the erection state, which requires further analyses on penile lymphatic system.

PDE5 inhibitors: breaking new grounds in the treatment of COVID-19

INTRODUCTION

Despite the ever-increasing occurrences of the coronavirus disease (COVID-19) cases around the world, very few medications have been validated in the clinical trials to combat COVID-19. Although several vaccines have been developed in the past quarter, the time elapsed between deployment and administration remains a major impediment.

CONTENT

Repurposing of pre-approved drugs, such as phosphodiesterase 5 (PDE5) inhibitors, could be a game-changer while lessening the burden on the current healthcare system. Repurposing and developing phosphodiesterase 5 (PDE5) inhibitors could extrapolate their utility to combat the SARS-CoV-2 infection, and potentially aid in the management of the symptoms associated with its newer variants such as BF.7, BQ.1, BQ.1.1, XBB.1.5, and XBB.1.16.

SUMMARY

Administration of PDE5 inhibitors via the oral and intravenous route demonstrates other potential off-label benefits, including anti-apoptotic, anti-inflammatory, antioxidant, and immunomodulatory effects, by intercepting several pathways. These effects can not only be of clinical importance in mild-to-moderate, but also moderate-to-severe SARS-CoV-2 infections. This article explores the various mechanisms by which PDE5 inhibitors alleviates the symptoms associated with COVID-19 as well as well as highlights recent studies and findings.

OUTLOOK

These benefits of PDE5 inhibitors make it a potential drug in the physicians' armamentarium in alleviating symptoms associated with SARS-CoV-2 infection. However, adequate clinical studies must be instituted to eliminate any untoward adverse events.

PDE5 inhibitors: breaking new grounds in the treatment of COVID-19

INTRODUCTION

Despite the ever-increasing occurrences of the coronavirus disease (COVID-19) cases around the world, very few medications have been validated in the clinical trials to combat COVID-19. Although several vaccines have been developed in the past quarter, the time elapsed between deployment and administration remains a major impediment.

CONTENT

Repurposing of pre-approved drugs, such as phosphodiesterase 5 (PDE5) inhibitors, could be a game-changer while lessening the burden on the current healthcare system. Repurposing and developing phosphodiesterase 5 (PDE5) inhibitors could extrapolate their utility to combat the SARS-CoV-2 infection, and potentially aid in the management of the symptoms associated with its newer variants such as BF.7, BQ.1, BQ.1.1, XBB.1.5, and XBB.1.16.

SUMMARY

Administration of PDE5 inhibitors via the oral and intravenous route demonstrates other potential off-label benefits, including anti-apoptotic, anti-inflammatory, antioxidant, and immunomodulatory effects, by intercepting several pathways. These effects can not only be of clinical importance in mild-to-moderate, but also moderate-to-severe SARS-CoV-2 infections. This article explores the various mechanisms by which PDE5 inhibitors alleviates the symptoms associated with COVID-19 as well as well as highlights recent studies and findings.

OUTLOOK

These benefits of PDE5 inhibitors make it a potential drug in the physicians' armamentarium in alleviating symptoms associated with SARS-CoV-2 infection. However, adequate clinical studies must be instituted to eliminate any untoward adverse events.

An overview of the history, current strategies, and potential future treatment approaches in erectile dysfunction: a comprehensive review

INTRODUCTION

Erectile dysfunction (ED) is one of the most common urologic problems in men worldwide, with an approximately high incidence rate, significantly affecting patients' quality of life and their sexual partners.

OBJECTIVES

Due to the association of this disorder with essential diseases such as cardiovascular disease and diabetes, its prevention and treatment are vital for overall human physiologic and psychological health. Along with reviewing the history of treatment and current methods, we seek new approaches to curb this issue in the future.

METHODS

In this review, investigations were based on the focus of each section's content or conducted on an ad hoc basis. Searches were performed in Scopus and PubMed.

RESULTS

In recent years, many treatments for ED have been reported besides oral administration of phosphodiesterase 5 inhibitors such as sildenafil and tadalafil (approved by the Food and Drug Administration). Common oral medications, intracavernous injections, herbal therapies (eg, herbal phosphodiesterase 5 inhibitors), and topical/transdermal medications are routine ED treatment approaches. Moreover, some novel medications are innovative candidates for completing ED's treatment protocols: stem cell injection, low-intensity extracorporeal shock wave therapy, platelet-rich plasma injection, gene therapy, amniotic fluid matrices, rho-kinase inhibitors, melanocortin receptor antagonists, maxi-K channel activators (ie, large-conductance calcium-activated potassium channels), guanylate cyclase activators, and nitric oxide donors.

CONCLUSION

Due to the importance of this complicated problem in men's society, a faster course of treatment trends toward new methods is needed to increase efficiency. Combining the mentioned treatments and attentively examining their efficacy through programmed clinical trials can be a big step toward solving this global problem.

Trends in treatments for erectile dysfunction in Chile between 2010 and 2020 with special focus on penile prostheses

OBJECTIVES

Evidence regarding demand trends for erectile dysfunction (ED) treatments are scarce in South America. This study aims to evaluate trends in ED treatments in Chile over a 10-year period (2010- 2020) and estimate the potential number of candidates for penile prosthesis.

MATERIALS AND METHODS

Sales trends of pharmacological treatments and penile prosthesis were obtained from market studies. The potential number of candidates for penile prosthesis implantation was calculated by crossing epidemiological data with previously reported ED prevalence, proportion of sexually active men, percentage of men seeking medical assistance for ED, and the proportion of patients who are non-responders to ED oral drug therapies Results: In the 10-year studied period, the Chilean male population older than 50 years increased 34.7%, with an average annual variation (AAV) of 3.4%. For the same period, the sales of oral drug therapies for ED increased by 71.3% (AAV 6.2%), the sales of intracavernosal vasoactive agents (ICVA) decreased by 0.4% (AAV -0.2%), and penile prosthesis sales increased by 113% (AAV 6.7%). We estimated that only 0.05% of sexually active men older than 50 years old with ED who sought medical assistance finally had a penile prosthesis implanted to manage their condition.

CONCLUSIONS

Demand for ED oral drug therapies significantly increased in Chile during the last decade, while ICVA remained stable. The annual rate of penile prosthesis implantation increased. However, the gap between the potential penile prosthesis candidates and the actual number of devices implanted is suspected to remain extremely high.

Recreational Use of Oral PDE5 Inhibitors: The Other Side of Midnight

BACKGROUND

Nowadays, Oral phosphodiesterase type 5 inhibitors (PDE5Is) are widely used for the treatment of erectile dysfunction (ED). However, these drugs have become abused among some men for recreational use to enhance their sexual performance.

OBJECTIVE

To shed a light on the recreational use of oral PDE5Is.

METHODS

A literature review was performed in the PubMed, Medline Medical Subject Heading, Science Direct, Scopus, Cochrane Library, EMBASE, CINAHL, Academic Search Complete, Google scholar, Egyptian Knowledge Bank (EKB) databases, Medline, Embase, and Chem ID using the keywords; sexual health, erectile dysfunction, recreational use/abuse, phosphodiesterase type 5 inhibitors, sildenafil, tadalafil, vardenafil, avanafil, and adverse effects.

RESULTS

Overall, 52 studies were retained for review out of 166 papers. Twenty-two studies that assessed the prevalence of the problem were investigated including 25,279 men from different countries. Most of these studies were cross-sectional studies that depend on multiple questionnaires representing the extent as well as the attitude of the recreational use of PDE5Is.

CONCLUSION

Oral PDE5Is have become used among some men for recreational use to enhance their sexual performance. To counteract the possible side effects of such abuse, the media, as well as health authorities, should be aware of the potential adverse effects of such abuse and strengthen the regulatory activity to protect the customers from such risks. Mostafa T, Alghobary MF. Recreational Use of Oral PDE5 Inhibitors: The Other Side of Midnight. Sex Med Rev 2021;XX:XXX-XXX.

Effect of the icariin on endothelial microparticles, endothelial progenitor cells, platelets, and erectile function in spontaneously hypertensive rats

OBJECTIVES

To investigate the effect of icariin on endothelial microparticles, endothelial progenitor cells, platelets, and erectile function in spontaneously hypertensive rats.

MATERIALS AND METHODS

Twelve 8-week-old healthy male Wistar-Kyoto rats and 12 spontaneously hypertensive rats were randomly divided into four following groups: Wistar-Kyoto control group (normal saline 1 ml/d given by gavage), Wistar-Kyoto + icariin group (icariin 10 mg/kg × d dissolved in 1 ml normal saline and given by gavage), spontaneously hypertensive rats control group (normal saline 1 ml/d given by gavage), and spontaneously hypertensive rats + icariin group (icariin 10 mg/kg × d dissolved in 1 ml normal saline and given by gavage). Four weeks later, the maximum intracavernous pressure/mean arterial pressure, platelet count, mean platelet volume, platelet distribution width, endothelial microparticles, endothelial progenitor cells, and vitronectin receptor were measured in each group.

RESULTS

Under 3 or 5 V electrical stimulation, the maximum intracavernous pressure/mean arterial pressure in the spontaneously hypertensive rats + icariin group (0.23 ± 0.03, 0.38 ± 0.02) was significantly higher compared to the spontaneously hypertensive rats control group (0.12 ± 0.02, 0.20 ± 0.02) (p<0.05). Platelet count, mean platelet volume, and platelet distribution width in the spontaneously hypertensive rats + icariin group (1103.67 ± 107.70 × 10⁹ /L, 9.08 ± 0.50 fl, 11.87 ± 0.45%) were significantly lower than those in the spontaneously hypertensive rats control group (1298.00 ± 89.54 × 10⁹ /L, 9.72 ± 0.44 fl, 13.03 ± 0.59%) (all p < 0.05). Endothelial microparticles, endothelial progenitor cells, and vitronectin receptor in the spontaneously hypertensive rats + icariin group (1.01 ± 0.28%, 1.53 ± 0.65%, 2.13 ± 0.53%) were significantly lower than those in the spontaneously hypertensive rats control group (1.58 ± 0.19%, 2.71 ± 0.64%, 3.76 ± 0.52%) (all p < 0.05). Moreover, maximum intracavernous pressure/mean arterial pressure was strongly negatively correlated with platelet distribution width and vitronectin receptor (r > 0.7), and maximum intracavernous pressure/mean arterial pressure was moderately negatively correlated with mean platelet volume, endothelial microparticles, and endothelial progenitor cells (0.5 < r<0.7).

CONCLUSION

Icariin may improve erectile function in spontaneously hypertensive rats by reducing the content of endothelial microparticles in blood and inhibiting the activation of the platelets. Endothelial microparticles, endothelial progenitor cells, and platelet activation-related (mean platelet volume, platelet distribution width, and vitronectin receptor) can be used as indicators for icariin to improve erectile function in spontaneously hypertensive rats.

Non-invasive positive airway pressure therapy for improving erectile dysfunction in men with obstructive sleep apnoea

BACKGROUND

Obstructive sleep apnoea syndrome (OSAS) is associated with several chronic diseases, including erectile dysfunction (ED). The association of OSAS and ED is far more common than might be found by chance; the treatment of OSAS with non-invasive positive airway pressure therapy is associated with improvement of respiratory symptoms, and may contribute to the improvement of associated conditions, such as ED.

OBJECTIVES

To assess the effectiveness and acceptability of non-invasive positive airway pressure therapy for improving erectile dysfunction in OSAS.

SEARCH METHODS

We identified studies from the Cochrane Airways Trials Register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, AMED EBSCO, and LILACS, the US National Institutes of Health ongoing trials register ClinicalTrials.gov, and the World Health Organisation international clinical trials registry platform to 14 June 2021, with no restriction on date, language, or status of publication. We checked the reference lists of all primary studies, and review articles for additional references, and relevant manufacturers' websites for study information. We also searched specific conference proceedings for the British Association of Urological Surgeons; the European Association of Urology; and the American Urological Association to 14 June 2021.

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) with a parallel or cross-over design, or cluster-RCTs, which included men aged 18 years or older, with OSAS and ED. We considered RCTs comparing any non-invasive positive airway pressure therapy (such as continuous positive airways pressure (CPAP), bilevel positive airway pressure (BiPAP), variable positive airway pressure (VPAP), or similar devices) versus sham, no treatment, waiting list, or pharmacological treatment for ED. The primary outcomes were remission of ED and serious adverse events; secondary outcome were sex-related quality of life, health-related quality of life, and minor adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently conducted study selection, data extraction, and risk of bias assessment. A third review author solved any disagreement. We used the Cochrane RoB 1 tool to assess the risk of bias of the included RCTs. We used the GRADE approach to assess the certainty of the body of evidence. To measure the treatment effect on dichotomous outcomes, we used the risk ratio (RR); for continuous outcomes, we used the mean difference (MD). We calculated 95% confidence intervals (CI) for these measures. When possible (data availability and homogeneous studies), we used a random-effect model to pool data with a meta-analysis.

MAIN RESULTS

We included six RCTs (all assessing CPAP as the non-invasive positive airway pressure therapy device), with a total of 315 men with OSAS and ED. All RCTs presented some important risk of bias related to selection, performance, assessment, or reporting bias. None of included RCTs assessed the ED remission rate, and we used the provided ED mean scores as a proxy. CPAP versus no CPAP There is uncertainty about the effect of CPAP on mean ED scores after 4 weeks, using the International index of erectile function (IIEF-5, higher = better; MD 7.50, 95% CI 4.05 to 10.95; 1 RCT; 27 participants; very low-certainty evidence), and after 12 weeks (IIEF-ED, ED domain; MD 2.50, 95% CI -1.10 to 6.10; 1 RCT; 57 participants; very low-certainty evidence, downgraded due to methodological limitations and imprecision). There is uncertainty about the effect of CPAP on sex-related quality of life after 12 weeks, using the Self-esteem and relationship test (SEAR, higher = better; MD 1.00, 95% CI -8.09 to 10.09; 1 RCT; 57 participants; very low-certainty evidence, downgraded due to methodological limitations and imprecision); no serious adverse events were reported after 4 weeks (1 RCT; 27 participants; very low-certainty evidence, downgraded due to methodological limitations and imprecision). CPAP versus sham CPAP One RCT assessed this comparison (61 participants), but we were unable to extract outcomes for this comparison due to the factorial design and reporting of this trial. CPAP versus sildenafil (phosphodiesterase type 5 inhibitors) Sildenafil may slightly improve erectile function at 12 weeks when compared to CPAP, measured with the IIEF-ED (MD -4.78, 95% CI -6.98 to -2.58; 3 RCTs; 152 participants; I² = 59%; low-certainty evidence, downgraded due to methodological limitations). There is uncertainty about the effect of CPAP on sex-related quality of life after 12 weeks, measured with the Erectile Dysfunction Inventory of Treatment Satisfaction questionnaire (EDITS, higher = better; MD -1.24, 95% CI -1.80 to -0.67; 2 RCTs; 122 participants; I² = 0%; very low-certainty evidence, downgraded due to methodological limitations). No serious adverse events were reported for either group (2 RCTs; 70 participants; very low-certainty evidence, downgraded due to methodological limitations and imprecision). There is uncertainty about the effects of CPAP when compared to sildenafil for the incidence of minor adverse events (RR 1.33, 95% CI 0.34 to 5.21; 1 RCT; 40 participants; very low-certainty evidence, downgraded due to methodological limitations and imprecision). The confidence interval was wide and neither a significant increase nor reduction in the risk of minor adverse events can be ruled out with the use of CPAP (4/20 men complained of nasal dryness in the CPAP group, and 3/20 men complained of transient flushing and mild headache in the sildenafil group).

AUTHORS' CONCLUSIONS

When compared with no CPAP, we are uncertain about the effectiveness and acceptability of CPAP for improving erectile dysfunction in men with obstructive sleep apnoea. When compared with sildenafil, there is some evidence that sildenafil may slightly improve erectile function at 12 weeks.

Early health economic analysis of 1.5 T MRI-guided radiotherapy for localized prostate cancer: Decision analytic modelling

BACKGROUND AND PURPOSE

1.5 Tesla magnetic resonance imaging radiotherapy linear accelerator (MR-Linac) is gaining interest for treatment of localized prostate cancer. Clinical evidence is lacking and it therefore remains uncertain whether MR-Linac is cost-effective. An early health economic analysis was performed to calculate the necessary relative reduction in complications and the maximum price of MR-Linac (5 fractions) to be cost-effective compared to 5, 20 and 39 fractionation schedules of external beam radiotherapy (EBRT) and low-dose-rate (LDR) brachytherapy.

MATERIALS AND METHODS

A state transition model was developed for men with localized prostate cancer. Complication rates such as grade ≥2 urinary, grade ≥2 bowel and sexual complications, and utilities were based on systematic literature searches. Costs were estimated from a Dutch healthcare perspective. Threshold analyses were performed to identify the thresholds of complications and costs for MR-Linac to be cost-effective, while holding other outcomes such as biochemical progression and mortality constant. One-way sensitivity analyses were performed to outline uncertainty outcomes.

RESULTS

At €6460 per patient, no reductions in complications were needed to consider MR-Linac cost-effective compared to EBRT 20 and 39 fractions. Compared to EBRT 5 fractions and LDR brachytherapy, MR-Linac was found to be cost-effective when complications are relatively reduced by 54% and 66% respectively. Results are highly sensitive to the utilities of urinary, bowel and sexual complications and the probability of biochemical progression.

CONCLUSIONS

MR-Linac is found to be cost-effective compared to 20 and 39 fractions EBRT at baseline. For MR-Linac to become cost-effective over 5 fractions EBRT and LDR brachytherapy, it has to reduce complications substantially or be offered at lower costs.

Erectile dysfunction and penile rehabilitation after pelvic fracture: a systematic review and meta-analysis

OBJECTIVE

To investigate the rate of erectile dysfunction (ED) after pelvic ring fracture (PRF).

DESIGN

Systematic review and meta-analysis.

METHODS

A systematic literature search of the Cochrane, EMBASE, MEDLINE, Scopus and Web of Science Library databases was conducted in January 2020. Included were original studies performed on humans assessing ED after PRF according to the 5-item International Index of Erectile Function (IIEF-5) questionnaire and fracture classification following Young and Burgess, Tile or Arbeitsgemeinschaft für Osteosynthesefragen/Orthopedic Trauma Association. Furthermore, interventional cohort studies assessing the effect of penile rehabilitation therapy with phosphodiesterase-5-inhibitors (PDE-5-I) on IIEF-5 scores compared before and after treatment were included. Results were presented as forest plots of proportions of patients with ED after PRF or mean changes on IIEF-5 questionnaires before and after penile rehabilitation. Studies not included in the quantitative analysis were narratively summarised. Risk of bias assessment was conducted using the revised tool for the Quality Assessment on Diagnostic Accuracy Studies.

RESULTS

The systematic literature search retrieved 617 articles. Seven articles were included in the qualitative analysis and the meta-analysis. Pooled proportions revealed 37% of patients with ED after suffering any form of PRF (result on probability scale pr=0.37, 95% CI: 0.26 to 0.50). Patients after 3 months of penile rehabilitation therapy reported a higher IIEF-5 score than before (change score=6.5 points, 95% CI: 2.54 to 10.46, p value=0.0013).

CONCLUSION

Despite some heterogeneity and limited high-quality research, this study concludes that patients suffering from any type of PRF have an increased risk of developing ED. Oral intake of PDE-5-I for the purpose of penile rehabilitation therapy increases IIEF-5 scores and may relevantly influence quality-of-life in these patients.

PROSPERO REGISTRATION NUMBER

CRD42020169699.

Could Oral Phosphodiesterase 5 Inhibitors Have a Potential Adjuvant Role in Combating COVID-19 Infection?

INTRODUCTION

The recent global outbreak of coronavirus disease 2019 (COVID-19) has become a pandemic with a lot of sufferers. Excessive inflammation, exaggerated immune response, with ultimate apoptosis contribute to COVID-19 pathology that progress to acute lung acute respiratory distress.

OBJECTIVE

To shed a light on the likely benefits of the oral phosphodiesterase 5 (PDE5) inhibitor adjuvant role in combating COVID-19 infection.

METHODS

A literature review was performed in the PubMed/Medline database, Scopus, Cochrane Library, EMBASE, Academic Search Complete, Google Scholar, and CINAHL databases using the keywords COVID-19; phosphodiesterase-5 inhibitors; cytokine storm; respiratory distress.

RESULTS

Despite the worsening trends of COVID-19, still no drugs are validated to have significant clinical efficacy in the treatment of patients with COVID-19 in large-scale studies. While the progress toward a curative agent and/or vaccine is certainly hopeful, the principal limiting factor in such public health emergencies is always the time. Therefore, a preexisting licensed therapeutic(s) might offer a reprieve to the healthcare systems operating at the edge of capacity. In this context, the innovation of oral PDE5 inhibitors with their valuable effects on erection have provided a breakthrough in the treatment of erectile dysfunction and opened new fields of clinical application for this class of drugs. Oral PDE5 inhibitors have been demonstrated to possess many beneficial useful additional implications with acknowledged anti-inflammatory, antioxidant, immune response regulation, and antiapoptotic properties. These properties have been elucidated through the nitric oxide/soluble guanylyl cyclase/cyclic guanylate monophosphate pathway in addition to the emerged hemeoxygenase-1 enzyme as well as hydrogen sulfide pathways. These properties could support repurposing oral PDE5 inhibitors' potential adjuvant use in targeting different aspects of COVID-19 infection.

CONCLUSION

Oral PDE5 inhibitors retain several acknowledged off-labeled useful implications with anti-inflammatory, antioxidant, immune response regulation, and antiapoptotic properties. These properties may support repurposing oral PDE5 inhibitors' potential adjuvant use in the protocols combating COVID-19 manifestations. Mostafa T. Could Oral Phosphodiesterase 5 Inhibitors Have a Potential Adjuvant Role in Combating Coronavirus Disease 2019 Infection? Sex Med Rev 2021;9:15-22.

Sildenafil beyond erectile dysfunction and pulmonary arterial hypertension: Thinking about new indications

Sildenafil, approved two decades ago, is the inhibitor of phosphodiesterase 5 (PDE5). First of all, it was designated for angina pectoris, but soon it showed a wonderful efficacy in erectile dysfunction (ED) and then pulmonary arterial hypertension (PAH). Due to the distribution of phosphodiesterase (PDE) in almost all organs, maybe it effects other diseases. Hence, a great number of investigations began to understand the role of PDEi in different organs. Preliminary research on sildenafil in cell culture and animal models has yielded promising results. Soon, a greater number of animal researches and clinical trials joined them. The results disclosed sildenafil can have beneficial effects in each organ such as heart, liver, kidney, brain, and intestines. Furthermore, it has significantly improved the prognosis of organ ischemia in various animal models. Clinical trials in several diseases, such as recurrent spontaneous miscarriage, fatty liver disease, bronchopulmonary dysplasia (BPD), heart failure, and premature ejaculation (PE) brought promising results. Although some clinical trials are available on the effects of sildenafil on various diseases, further studies on humans are needed to consolidate the ultimate effects of sildenafil. The aim of this review was to describe the effects of sildenafil on each organ and explain its mechanisms of action. Further, other PDE inhibitors such as tadalafil and vardenafil have been briefly discussed in parts of this review.

Glutamate in Male and Female Sexual Behavior: Receptors, Transporters, and Steroid Independence

The survival of animal species predicates on the success of sexual reproduction. Neurotransmitters play an integral role in the expression of these sexual behaviors in the brain. Here, we review the role of glutamate in sexual behavior in rodents and non-rodent species for both males and females. These encompass the release of glutamate and correlations with glutamate receptor expression during sexual behavior. We then present the effects of glutamate on sexual behavior, as well as the effects of antagonists and agonists on different glutamate transporters and receptors. Following that, we discuss the potential role of glutamate on steroid-independent sexual behavior. Finally, we demonstrate the interaction of glutamate with other neurotransmitters to impact sexual behavior. These sexual behavior studies are crucial in the development of novel treatments of sexual dysfunction and in furthering our understanding of the complexity of sexual diversity. In the past decade, we have witnessed the burgeoning of novel techniques to study and manipulate neuron activity, to decode molecular events at the single-cell level, and to analyze behavioral data. They pose exciting avenues to gain further insight into future sexual behavior research. Taken together, this work conveys the essential role of glutamate in sexual behavior.

Could Oral Phosphodiesterase 5 Inhibitors Have a Potential Adjuvant Role in Combating COVID-19 Infection?

INTRODUCTION

The recent global outbreak of coronavirus disease 2019 (COVID-19) has become a pandemic with a lot of sufferers. Excessive inflammation, exaggerated immune response, with ultimate apoptosis contribute to COVID-19 pathology that progress to acute lung acute respiratory distress.

OBJECTIVE

To shed a light on the likely benefits of the oral phosphodiesterase 5 (PDE5) inhibitor adjuvant role in combating COVID-19 infection.

METHODS

A literature review was performed in the PubMed/Medline database, Scopus, Cochrane Library, EMBASE, Academic Search Complete, Google Scholar, and CINAHL databases using the keywords COVID-19; phosphodiesterase-5 inhibitors; cytokine storm; respiratory distress.

RESULTS

Despite the worsening trends of COVID-19, still no drugs are validated to have significant clinical efficacy in the treatment of patients with COVID-19 in large-scale studies. While the progress toward a curative agent and/or vaccine is certainly hopeful, the principal limiting factor in such public health emergencies is always the time. Therefore, a preexisting licensed therapeutic(s) might offer a reprieve to the healthcare systems operating at the edge of capacity. In this context, the innovation of oral PDE5 inhibitors with their valuable effects on erection have provided a breakthrough in the treatment of erectile dysfunction and opened new fields of clinical application for this class of drugs. Oral PDE5 inhibitors have been demonstrated to possess many beneficial useful additional implications with acknowledged anti-inflammatory, antioxidant, immune response regulation, and antiapoptotic properties. These properties have been elucidated through the nitric oxide/soluble guanylyl cyclase/cyclic guanylate monophosphate pathway in addition to the emerged hemeoxygenase-1 enzyme as well as hydrogen sulfide pathways. These properties could support repurposing oral PDE5 inhibitors' potential adjuvant use in targeting different aspects of COVID-19 infection.

CONCLUSION

Oral PDE5 inhibitors retain several acknowledged off-labeled useful implications with anti-inflammatory, antioxidant, immune response regulation, and antiapoptotic properties. These properties may support repurposing oral PDE5 inhibitors' potential adjuvant use in the protocols combating COVID-19 manifestations. Mostafa T. Could Oral Phosphodiesterase 5 Inhibitors Have a Potential Adjuvant Role in Combating Coronavirus Disease 2019 Infection? Sex Med Rev 2021;9:15-22.

Drug Repositioning of the α1-Adrenergic Receptor Antagonist Naftopidil: A Potential New Anti-Cancer Drug?

Failure of conventional treatments is often observed in cancer management and this requires the development of alternative therapeutic strategies. However, new drug development is known to be a high-failure process because of the possibility of a lower efficacy than expected for the drug or appearance of non-manageable side effects. Another way to find alternative therapeutic drugs consists in identifying new applications for drugs already approved for a particular disease: a concept named "drug repurposing". In this context, several studies demonstrated the potential anti-tumour activity exerted by α1-adrenergic receptor antagonists and notably renewed interest for naftopidil as an anti-cancer drug. Naftopidil is used for benign prostatic hyperplasia management in Japan and a retrospective study brought out a reduced incidence of prostate cancer in patients that had been prescribed this drug. Further studies showed that naftopidil exerted anti-proliferative and cytotoxic effects on prostate cancer as well as several other cancer types in vitro, as well as ex vivo and in vivo. Moreover, naftopidil was demonstrated to modulate the expression of Bcl-2 family pro-apoptotic members which could be used to sensitise cancer cells to targeting therapies and to overcome resistance of cancer cells to apoptosis. For most of these anti-cancer effects, the molecular pathway is either not fully deciphered or shown to involve α1-adrenergic receptor-independent pathway, suggesting off target transduction signals. In order to improve its efficacy, naftopidil analogues were designed and shown to be effective in several studies. Thereby, naftopidil appears to display anti-cancer properties on different cancer types and could be considered as a candidate for drug repurposing although its anti-cancerous activities need to be studied more deeply in prospective randomized clinical trials.

Drug delivery options and therapeutic advances in the management of erectile dysfunction

INTRODUCTION

Erectile dysfunction (ED) is defined as the inability to achieve or maintain an erection sufficient for satisfactory sexual performance. It is estimated that 20-30% of adult men will have at least one episode of ED during their lifetime and the prevalence increases with age. ED is known to have significant negative psychological implications for men, resulting in impaired functional status and a greater prevalence of anxiety and depression.

AREAS COVERED

Medications for the treatment of erectile dysfunction largely revolve around oral, injection, and topical therapies. Though all three modalities are widely used, each delivery option has its own advantages and specific indications. Likewise, there are several new developing treatments for ED that may change the landscape of treatment. The goal of this review is to summarize contemporary drug delivery options used in the treatment of ED and highlight future promising pharmacological developments.

EXPERT OPINION

There are a myriad of new developments on the horizon including new PDE5Is and drug targets, nanotechnology enhancements, stem cell and gene therapy, shockwave therapy, and platelet-rich plasma injections. These are all promising new methods to not only treat ED but also to address the pathology and prevent or eliminate further damage.

Acupuncture for erectile dysfunction in post-stroke patients: Study Protocol Clinical Trial (SPIRIT Compliant)

INTRODUCTION

Erectile dysfunction refers to the continued inability of the penis to reach and maintain sufficient erections to achieve a satisfactory sex life and last at least 6 months. As part of traditional Chinese medicine, acupuncture has been widely used in clinical practice. In order to evaluate, the exact effect of acupuncture on the clinical efficacy of patients with Post-stroke Erectile dysfunction (PSED), this experiment uses randomized controlled experiments.

METHODS/DESIGN

This pragmatic randomized controlled trial will recruit 103 patients who are diagnosed with PSED. Simple randomization to conventional treatment with a 1:1 allocation ratio will be used. Ten 30-min acupuncture sessions will be provided to patients assigned to the Intervention group. All participants will continue to receive conventional treatment. The selection of outcomes will be evaluated by International Erectile Function Index-5 (IIEF-5) score at week 8.

DISCUSSION

This trial may provide evidence regarding the clinical effectiveness, safety, and cost-effectiveness of acupuncture for patients with PSED.

TRIAL REGISTRATION

ClinicalTrials.gov, ChiCTR2000030231, Registered on February 25, 2020.

Development of novel phosphodiesterase 5 inhibitors for the therapy of Alzheimer's disease

Nitric oxide (NO) is a gaseous molecule that plays a multifactorial role in several cellular processes. In the central nervous system, the NO dual nature in neuroprotection and neurotoxicity has been explored to unveil its involvement in Alzheimer's disease (AD). A growing body of research shows that the activation of the NO signaling pathway leading to the phosphorylation of the transcription factor cyclic adenine monophosphate responsive element binding protein (CREB) (so-called NO/cGMP/PKG/CREB signaling pathway) ameliorates altered neuroplasticity and memory deficits in AD animal models. In addition to NO donors, several other pharmacological agents, such as phosphodiesterase 5 (PDE5) inhibitors have been used to activate the pathway and rescue memory disorders. PDE5 inhibitors, including sildenafil, tadalafil and vardenafil, are marketed for the treatment of erectile dysfunction and arterial pulmonary hypertension due to their vasodilatory properties. The ability of PDE5 inhibitors to interfere with the NO/cGMP/PKG/CREB signaling pathway by increasing the levels of cGMP has prompted the hypothesis that PDE5 inhibition might be used as an effective therapeutic strategy for the treatment of AD. To this end, newly designed PDE5 inhibitors belonging to different chemical classes with improved pharmacologic profile (e.g. higher potency, improved selectivity, and blood-brain barrier penetration) have been synthesized and evaluated in several animal models of AD. In addition, recent medicinal chemistry effort has led to the development of agents concurrently acting on the PDE5 enzyme and a second target involved in AD. Both marketed and investigational PDE5 inhibitors have shown to reverse cognitive defects in young and aged wild type mice as well as transgenic mouse models of AD and tauopathy using a variety of behavioral tasks. These studies confirmed the therapeutic potential of PDE5 inhibitors as cognitive enhancers. However, clinical studies assessing cognitive functions using marketed PDE5 inhibitors have not been conclusive. Drug discovery efforts by our group and others are currently directed towards the development of novel PDE5 inhibitors tailored to AD with improved pharmacodynamic and pharmacokinetic properties. In summary, the present perspective reports an overview of the correlation between the NO signaling and AD, as well as an outline of the PDE5 inhibitors used as an alternative approach in altering the NO pathway leading to an improvement of learning and memory. The last two sections describe the preclinical and clinical evaluation of PDE5 inhibitors for the treatment of AD, providing a comprehensive analysis of the current status of the AD drug discovery efforts involving PDE5 as a new therapeutic target.

Sildenafil citrate long-term treatment effects on cardiovascular reactivity in a SHR experimental model of metabolic syndrome

Much evidence indicates that metabolic syndrome is strongly correlated with a decrease in nitric oxide and an increase in oxidative stress leading to cardiovascular alterations. In recent years, gut microbiota has emerged as a new contributor to the metabolic syndrome establishment and associated cardiovascular diseases, but the underlying mechanisms remain unclear. We hypothesized that a positive modulation of cyclic guanosine monophosphate (cGMP) pathway, through phosphodiesterase type 5 (PDE5) inhibition could prevent cardiovascular alterations and gut dysbiosis that may be associated to metabolic syndrome. Spontaneously hypertensive rats (SHR) were randomly divided into 4 groups: control, cafeteria diet (CD) and sildenafil citrate treated groups (5mg/kg per os) were given either a CD or a standard chow diet for 10 weeks. Body weight, arterial blood pressure and glucose tolerance test were monitored. At the 10^th week, cardiac inotropy and coronary perfusion pressure were evaluated on isolated heart according to Langendorff method. Cumulative concentration response curves to phenylephrine and acetylcholine were determined on thoracic aorta rings for vascular reactivity evaluation. Faecal samples were collected for the gut microbiota analysis. Compared to the control group, CD-fed rats showed a significant increase in body weight gain, arterial blood pressure and were glucose intolerant. This group showed also a decrease in β-adrenoceptor-induced cardiac inotropy and coronary vasodilation. Gut microbiota analysis revealed a significant reduction in the abundance of Lactobocillus spp in cafeteria diet-fed rats when compared to the control ones. Sildenafil citrate long-term treatment decreased weight gain and arterial blood pressure, improved coronary vasodilation and reduced α_1-adrenoceptor-induced vasoconstriction in CD group. However, it did not reverse gut dysbiosis induced by chronic CD feeding. These results suggest that cGMP pathway targeting may be a potential therapeutic strategy for the management of the metabolic syndrome and associated cardiovascular disorders.

The rate of deterioration of erectile function increases with age: results from a longitudinal population based survey

Background: Increasing age as a risk factor for erectile dysfunction (ED) is in most studies assumed to be a linear function. If this is not the case the assumption could lead to bias, e.g. when men of different ages are compared in interventional studies on ED. Objective: To explore the risk of developing ED over time for men from different age groups. Materials and methods: A questionnaire was sent to a number of male residents in Gothenburg, Sweden, in 1992 (n = 10,458). Men were randomly selected according to year of birth to obtain several cohorts at 5-year intervals of ages 45, 50, 55 years, etc., up to the age of 85 or older. In 2003 an analogous, slightly expanded, questionnaire was sent to a random sample of men from the age cohorts 46, 51 years, etc. (n = 10,845). A total of 4072 men received both surveys, thereby constituting a group of men followed longitudinally for 11 years. The future risk of developing ED in the different age cohorts, adjusted for a number of ED risk factors, was then assessed. Results: A total of 3257 men responded to both questionnaires (response rate = 80%, age range = 56-103 years). The risk of having ED increased substantially with increasing age, both within each survey and longitudinally between the surveys. The adjusted risk of developing ED within the next 11 years increased with a factor of 10, from 1.8% at the age of 45 years at baseline to as much as 11.4% at the age of 65 years. Conclusion: Age as a risk-factor for ED is a non-linear function and should be adjusted as such to avoid bias when including men of different ages in interventional studies on ED.

Flushing Disorders Associated with Gastrointestinal Symptoms: Part 2, Systemic Miscellaneous Conditions

Flushing disorders with involvement of the gastrointestinal tract represent a heterogeneous group of conditions. In part 1 of this review series, neuroendocrine tumors (NET), mast cell activation disorders (MCAD), and hyperbasophilia were discussed. In this section we discuss the remaining flushing disorders which primarily or secondarily involve the gastrointestinal tract. This includes dumping syndrome, mesenteric traction syndrome, rosacea, hyperthyroidism and thyroid storm, anaphylaxis, panic disorders, paroxysmal extreme pain disorder, and food, alcohol and medications. With the exception of paroxysmal pain disorders, panic disorders and some medications, these disorders presents with dry flushing. A detailed and comprehensive family, social, medical and surgical history, as well as recognizing the presence of other systemic symptoms are important in distinguishing the different disease that cause flushing with gastrointestinal symptoms.

Quality of erections by age group in men with erectile dysfunction

AIMS

The aim of this study was to assess erection quality with sildenafil vs placebo and adverse events (AEs) according to age (≤45, 46-55 and ≥56 years) in 997 men with erectile dysfunction (ED) using pooled data from four randomized, double-blind, placebo-controlled, flexible-dose trials.

METHODS

The trials included 6- to 10-week treatment periods. The starting sildenafil dose was 50 mg, taken ~1 hour before sexual activity but not more than once daily, with subsequent adjustment to 100 or 25 mg based on efficacy and safety. Exclusion criteria included blood pressure <90/50 or >170/110 mmHg, taking nitrate therapy or nitric oxide donors, severe cardiac failure/unstable angina or recent stroke or myocardial infarction. Changes from baseline in Quality of Erection Questionnaire (QEQ), International Index of Erectile Function (IIEF) and Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS) scores were analysed.

RESULTS

Improvements in QEQ scores with sildenafil vs placebo were significant (P<.0001) for the overall sample (33.7 sildenafil; 8.1 placebo) and each age group (≤45 years: 38.5 sildenafil, 13.9 placebo; 46-55 years: 34.9 sildenafil, 5.8 placebo; ≥56 years: 26.9 sildenafil, 4.9 placebo). IIEF Erectile Function domain (P<.0001), question 3 (achieving erection; P<.003), and question 4 (maintaining erection; P<.001) scores also improved significantly for the overall sample and each age group. Treatment satisfaction was significantly greater (P<.0001) with sildenafil vs placebo for the overall sample and each age group. The most common AEs with sildenafil were headache, flushing and nasal congestion in all age groups.

CONCLUSIONS

Sildenafil significantly improved erection quality across all age groups of men with ED. Efficacy improvements with sildenafil were consistent with the QEQ, IIEF, and EDITS. AEs were comparable across age groups. ClinicalTrials.gov ID: NCT00159900, NCT00147628, NCT00301262, NCT00343200.

Ethnicity and age as factors in sildenafil treatment of erectile dysfunction

INTRODUCTION

Sildenafil has been evaluated in >16 000 men with erectile dysfunction (ED) in double-blind, placebo-controlled trials.

AIM

To assess efficacy and safety of sildenafil in ED by ethnicity (white, black Asian) and age (≤45, 46-60, ≥61 years).

METHODS

Data were pooled from 38 double-blind, placebo-controlled, flexible-dose trials. Most had starting sildenafil doses of 50 mg once daily, ~1 hour before sexual activity, with adjustment to 100 or 25 mg as needed.

MAIN OUTCOME MEASURES

Change from baseline in International Index of Erectile Function erectile function (IIEF-EF) domain score assessed with analysis of covariance and a Global Assessment Question (GAQ; "Did the treatment improve your erections?") at endpoint assessed with logistic regression analysis.

RESULTS

4120 and 3714 men received sildenafil and placebo, respectively (2740 and 2671 White; 407 and 385 Black; 973 and 658 Asian). For sildenafil vs. placebo groups, overall treatment differences for IIEF-EF domain and GAQ were significant for each ethnic and age group (P<.0001); significant treatment-by-ethnicity and treatment-by-age interactions were also observed for change in IIEF-EF domain scores (P<.05), with differences significantly greater for White vs. Black (P<.0001), White vs. Asian (P=.0163), and Asian vs. Black (P=.0036) men. A significant treatment-by-ethnicity interaction was observed for GAQ (P=.0004). The OR comparison for GAQ was significantly greater (P=.0001) with sildenafil vs. placebo in White (OR=11.2) or Asian (OR=12.4) men vs. Black men (OR=5.1). Adverse-event rates were generally similar, with some age variations.

CONCLUSIONS

Sildenafil is effective and well-tolerated regardless of ethnicity or age; however, treatment effects can vary.

Treatment response to sildenafil in men with erectile dysfunction relative to concomitant comorbidities and age

AIM

To evaluate treatment response in men with erectile dysfunction (ED) and concomitant comorbidities.

METHODS

Data were pooled from 42 placebo-controlled, flexible-dose sildenafil trials. In most trials, the sildenafil dose was 50 mg, taken ~1 hour before sexual activity but not more than once daily, with adjustment to 100 or 25 mg as needed. The overall population (N=9413) was stratified by age (<45, 46-64, ≥65 years). Treatment response was defined as a minimal clinically important difference (MCID) from baseline in the International Index of Erectile Function-Erectile Function (IIEF-EF) domain score of >2, >5 and >7 for men with mild, moderate and severe ED at baseline, respectively, or an IIEF-EF domain score ≥26 (no ED) at end-point.

RESULTS

In the overall population, treatment response using the IIEF-EF MCID definition was significantly greater (P<.0001) with sildenafil vs placebo in men with no comorbidity (77% vs 33%), cardiovascular disease/hypertension only (71% vs 27%), diabetes only (63% vs 24%) or depression only (78% vs 29%). Using an IIEF-EF score ≥26, treatment response was significantly greater (P<.0001) with sildenafil vs placebo in men with no comorbidity (49% vs 17%), cardiovascular disease/hypertension only (48% vs 12%), diabetes only (40% vs 12%) or depression only (60% vs 17%). With each definition, the treatment response for each age and comorbidity was significantly greater (P≤.0065) with sildenafil vs placebo.

CONCLUSION

The treatment response was significantly greater with sildenafil vs placebo in men with ED and each comorbidity regardless of age.