Current therapies for premature ejaculation

Orexin receptors in paraventricular nucleus influence sexual behavior via regulating the sympathetic outflow in males

BACKGROUND

Orexins are hypothalamic neuropeptides associated with various neurophysiological activities such as sleep, arousal, and reward. However, there are few studies investigating the relationships between orexin receptors in the paraventricular nucleus and sexual behaviors.

OBJECTIVES

To explore the roles of orexin receptors in the paraventricular nucleus on sexual behaviors and uncover its potential mechanisms in males.

MATERIALS AND METHODS

Orexin A, orexin 1 receptor antagonist SB334867, and orexin 2 receptor antagonist TCS-OX2-29 were microinjected into the paraventricular nucleus to investigate the effects of orexin receptors on copulatory behavior testing of C57BL/6 mice. To explore if ejaculation could activate orexin 1 receptor-expressing neurons in the paraventricular nucleus, fluorescence immunohistochemical double staining was utilized. The levels of serum norepinephrine were measured and the lumbar sympathetic nerve activity was recorded to reflect the sympathetic nervous system activity. Moreover, the bulbospongiosus muscle-electromyogram was recorded and analyzed. To test whether perifornical/lateral hypothalamic area orexinergic neurons directly projected to the paraventricular nucleus, virus retrograde tracing technology was utilized.

RESULTS

Orexin A significantly enhanced sexual performance by shortening the intromission and ejaculation latencies, and increasing the mount and intromission frequencies, while the opposite outcomes appeared with SB334867. However, TCS-OX2-29 had no significant effects on sexual behaviors. Moreover, orexin A increased lumbar sympathetic nerve activity and the levels of serum norepinephrine, while SB334867 decreased lumbar sympathetic nerve activity and norepinephrine, which caused a significant decrease in sympathetic nervous system outflow. Meanwhile, a robust increase in the bulbospongiosus muscle-electromyogram activity was identified after microinjecting orexin A. Furthermore, cFos immunopositive cells were increased and double stained with orexin 1 receptor-expressing neurons in the mating group. Additionally, the retrograde tracing results demonstrated that orexinergic neurons in the perifornical/lateral hypothalamic area directly projected to the paraventricular nucleus.

CONCLUSIONS

Orexin 1 receptor in the paraventricular nucleus could influence the ejaculatory reflex via mediating the sympathetic nervous system activity, which might be of great importance in the treatment of premature ejaculation in the future.

Mechanism of Shugan Yidan fan, a Chinese herbal formula, in rat model of premature ejaculation

BACKGROUND

Premature ejaculation (PE) is one of the most common forms of sexual dysfunction in men, and multimodal therapeutic regimens should be considered to treat the condition. We developed a Chinese medicine herbal medicine, Shugan Yidan fang that had a significant clinical effect on PE patients, extending the time between penetration and ejaculation. However, the mechanism of this formula remains unclear. There is evidence that PE is associated with peripheral neuropathology, and the actions of dopamine (DA) and 5-hydroxytryptamine (5-HT). The aim of this study was to investigate the mechanism of Shugan Yidan fang's effect on PE through the relationship between sexual behavioristics and the level of neurotransmitters and dopamine receptors (DARs).

RESULTS

We showed that the male PE groups had a significant PE phenotype compared to healthy rats. Treatment with Shugan Yidan fang improved the behavioristics of the PE rats, and reduced the expression of DAR mRNA and protein while improving dopamine transporter levels.

CONCLUSIONS

Our study provided evidence for the beneficial effect of Shugan Yidan fang in PE therapy, and proposed a preliminary potential mechanism for the clinical application of the formula.

Vital function of DRD4 in dapoxetine medicated premature ejaculation treatment

BACKGROUND

Recently, dapoxetine has been widely accepted to treat premature ejaculation by fast-inhibiting 5-hydroxytryptamine reuptake. However, dapoxetine is not suitable for all premature ejaculation patients in clinical treatment. We need to investigate and reveal the mechanism deeply to solve this problem.

OBJECTIVES

To investigate and reveal the function of dopamine D4 receptor in dapoxetine medicated premature ejaculation treatment.

MATERIALS AND METHODS

A rat model was used to screen rapid ejaculators. The molecular mechanisms of histone serotonylation-mediated regulation of dopamine D4 receptor were demonstrated by chromatin immunoprecipitation, DNA pull-down, mass spectrometry analysis, and coimmunoprecipitation experiments. The biological function of dopamine D4 receptor was investigated through in vivo experiments by intrathecal injection of shDRD4 to knockdown dopamine D4 receptor.

RESULTS

In this study, we found that dapoxetine increased expression of 5-hydroxytryptamine and dopamine D4 receptor. We demonstrated that dapoxetine increased levels of 5-hydroxytryptamine, which promoted histone serotonylation (H3K4me3Q5ser) and transcription factor myeloid zinc-finger 1 complex binding on the dopamine D4 receptor promoter, upregulated the expression of dopamine D4 receptor and thus delayed ejaculation.

DISCUSSION

In this study, we demonstrated that dapoxetine increased the levels of 5-hydroxytryptamine, which promoted histone serotonylation and myeloid zinc-finger 1 complex binding to the dopamine D4 receptor promoter and upregulated the expression of dopamine D4 receptor, thus delaying ejaculation.

CONCLUSION

It is a novel mechanism that dapoxetine take effect of premature ejaculation treatment through upregulating the dopamine D4 receptor, which indicated that upregulated dopamine D4 receptor would enhance the dapoxetine effect in premature ejaculation treatment. This may lead to the development of novel therapeutic interventions for premature ejaculation.

Reasons and treatment strategy for discontinuation of dapoxetine treatment in premature ejaculation patients in China: A retrospective observational study

To assess dapoxetine discontinuation rates and the reasons for discontinuation in Chinese men with premature ejaculation (PE). Information on 906 PE outpatients was obtained from the hospital information system (HIS) in 2019. Of these, 150 patients were chosen. We analysed the dapoxetine discontinuation rate and the reasons for discontinuation over a 12-week follow-up period. The mean age of all patients was 33.6 years (range = 18-55), the mean PE duration was 12.36 ± 9.45 months. The 5-item International Index of Erectile Function (IIEF-5) score was 21.51 ± 3.80. A total of 37.3% of all the patients remained on the treatment until the 12th week. The cumulative discontinuation rates at the 4th, 8th and 12th weeks were 12%, 41.3% and 62.7%, respectively. The discontinuation rates for all the patients in weeks 0-4, weeks 4-8 and weeks 8-12 were 19.1%, 46.8% and 34.0%, respectively. After 4 weeks, the discontinuation rates dropped sharply. The reasons for patients' discontinuation were as follows: overexpectation of efficacy (30.9%), relapsing after drug withdrawal (26.6%), high cost (25.5%), side effects (9.6%), fear of drug addiction (4.3%), failure of follow-up (2.1%) and choosing other treatments (1.1%). The dapoxetine treatment discontinuation rate was very high. The main reasons for discontinuation were overexpectation of efficacy and high cost.

The Influence of Tramadol on Intravaginal Ejaculatory Latency Time and Sexual Satisfaction Score in Treating Patients With Premature Ejaculation: A Network Meta-Analysis

This network meta-analysis aimed at assessing the influence of tramadol on the intravaginal ejaculatory latency time (IELT) and sexual satisfaction score (SSS) in treating patients with premature ejaculation (PE). The PubMed, Embase, Cochrane Library databases (until July 2021), and original references of the included articles was systematically retrieved. The PRISMA checklist was followed. Finally, 14 articles including 1971 patients were included in this analysis. The results indicated that patients who were treated with tramadol (50 mg, 62 mg, 89 mg, and 100 mg) were superior to those treated with placebo in terms of IELT (p = .003, p < .00001, p < .00001, and p < .00001, respectively), but 25 mg tramadol did not show a significant advantage (p = .06). Patients who were treated with tramadol (50 mg and 100 mg) had a better efficacy than who were treated with 25 mg tramadol in the IELT (p < .00001 and p < .00001), but the effect of 50 mg tramadol and 100 mg tramadol were not significantly different (p = .17). The tramadol group had the better effect than the placebo group in the SSS (p < .0001). And 50 mg tramadol showed a significant improvement compared with 20 mg paroxetine, as assessed by the IELT (p = .03) and SSS (p = .03). Safety assessments including adverse events suggested that tramadol was well tolerated. Tramadol showed a better improvement of IELT and SSS than placebo or paroxetine, and 50 mg tramadol may be a more reasonable therapeutic dose for patients with PE.

Temperament-Character Traits and Attitudes Toward Premature Ejaculation in 4 Types of Premature Ejaculation

BACKGROUND

Although temperament-character traits and attitudes toward premature ejaculation (PE) are known to be associated with PE, it is of great significance to study them in PE. Moreover, few studies have evaluated these traits and attitudes in the new classification of 4 subtypes of PE.

AIM

We investigated the temperament-character traits and attitudes toward PE in 4 types of PE and their associations with PE.

METHODS

Between December 2018 and December 2019, we conducted a survey in our hospital, and enrolled 350 men who complained of PE and 252 men without any complaint of PE. Temperament-character traits and attitudes toward PE were independently assessed by the Temperament and Character Inventory-Revised and several targeted questions, respectively. The Index of Premature Ejaculation (IPE) was used to evaluate ejaculation control, sexual life satisfaction, and distress caused by PE.

OUTCOMES

The outcomes included differences of temperament-character traits and attitudes toward PE among 2 groups and their associations with PE.

RESULTS

Of the 2 groups, men with PE complaints had lower novelty seeking/self-transcendence (NS/ST) scores and higher harm avoidance (HA) scores vs men without any complaints of PE. Among the 4 types of PE, men with variable PE had the highest score of HA and lowest score of NS; the lowest score of ST was recorded in men with lifelong PE. Additionally, the total and subdomain scores of IPE in men with subjective PE were higher than the other subtypes of PE. After adjusting for age, positive correlations were observed in HA score and total and subdomain scores of IPE, whereas the inverse was true corresponding to NS and ST.

CLINICAL IMPLICATIONS

The current study has provided a new perspective for understanding the impact of psychological factors on PE.

STRENGTHS & LIMITATIONS

This is the first study to systematically assess the effects of personality traits and attitudes on PE, especially among the 4 types of PE. The main drawback is that the generalizability of this study may be limited by the fact that it was conducted in a single cultural/societal background.

CONCLUSION

Men who complained of PE tended to react with indifference or rejection to novelty, tended to feel unsatisfied, cannot effectively adapt to changes in the surrounding environment, and tended to avoid situations involving risk. These characteristics could lead to their becoming disheartened when faced with PE. Furthermore, the attitude of men with PE reflects the needs of the patient during treatment from one aspect. Gao P, Gao J Wang Y, et al. Temperament-Character Traits and Attitudes Toward Premature Ejaculation in 4 Types of Premature Ejaculation. J Sex Med 2021;18:72-82.

Selective dorsal neurotomy in the treatment of premature ejaculation: A protocol for systematic review and meta-analysis

INTRODUCTION

Premature ejaculation (PE) affects 8% to 30% of adult men worldwide. Recently, the incidence of PE is on the rise. A series of prior studies suggested that the incidence of PE is related to various biological factors as low testosterone, low serum vitamin D, diabetes, lower urinary tract symptoms, and other psychological factors. At present, the major treatments include selective serotonin reuptake inhibitors antidepressants (dapoxetine, paroxetine), topical anesthetics, phosphodiesterase-5 inhibitor, circumcision, and selective dorsal neurotomy (SDN). The previous study found that SDN is effective for PE.

METHODS AND ANALYSIS

The electronic databases of MEDLINE, PubMed, Web of Science, EMBASE, Cochrane Library, Clinicaltrials. org, China National Knowledge Infrastructure Database (CNKI), Wan fang Database, China Biology Medicine Database (CBM), VIP Science Technology Periodical Database, Chinese Clinical Trial Registry will be retrieved. All the randomized controlled trials of selective dorsal penile neurotomy for patients with PE will be included. The outcome includes intravaginal ejaculation latency time and Chinese Index of Sexual Function for Premature Ejaculation-5. We will conduct this study strictly according to the Cochrane Handbook for Systematic Reviews of Interventions.

RESULTS

The present study is a protocol for systematic review and meta-analysis without results, and data analysis will be carried out after the protocol. We will share our findings on June 30th of 2021.

CONCLUSION

SDN can effectively prolong IELT, but its efficacy has not been assessed scientifically and systematically. To address this limitation, this study will inspect the efficacy and safety of the SDN treatment in patients with PE.

ETHICS AND DISSEMINATION

Formal ethical approval is not required in this protocol. We will collect and analyze data based on published studies, and since there are no patients involved in this study, individual privacy will not be under concerns. The results of this review will be disseminated to peer-reviewed journals or submit to related conferences.

PROTOCOL REGISTRATION NUMBER

INPLASY202070084.

Efficacy of microsurgical varicocelectomy in the treatment of premature ejaculation: A protocol for systematic review and meta-analysis

INTRODUCTION

Premature ejaculation (PE) is the most common type of sexual disorder among men which comprises a great of problems. Varicocele is defined as the dilation of the pampiniform venous plexus draining the testicle. At present, selective serotonin reuptake inhibitors antidepressants, topical anesthetics, tramadol, phosphodiesterase type 5 inhibitors are the common alternative strategy to improve PE. However, these therapeutic measures have several shortcomings and side effects. Recently, the correlation between varicocele and PE has attracted the attention of some researchers. A few studies consider microsurgical varicocelectomy can be a new remedy for PE. But it is still absent enough a great deal of convincing evidence. The study will assess the effectiveness and safety of the microsurgical varicocelectomy treatment in PE patients.

METHODS AND ANALYSIS

Electronic databases including English databases (PubMed, MEDLINE, EMBASE, Web of Science, Cochrane Library) and Chinese databases (China National Knowledge Infrastructure, China Biology Medicine Database, Wanfang Database, VIP Database) will be searched from their inception to December 2020 to recognize related studies. All the randomized controlled trials of microsurgical varicocelectomy for the management of PE patients will be included. The potential outcome will include intravaginal ejaculation latency time, Chinese index of sexual function for premature ejaculation-5, visual analogue score, premature ejaculation diagnostic tool, success treatment rate, serum testosterone levels. We will conduct this study strictly according to the Cochrane Handbook for systematic reviews of interventions.

RESULTS

The current study is a protocol for systematic review and meta-analysis without results, and data analysis will be carried out after the protocol. We will share our findings in the February 28, 2021.

CONCLUSION

This systematic review will provide more evidence to assess whether microsurgical varicocelectomy is an effective intervention for patients with PE. The results will be published in a public issue journal and offer the urologists and andrologists help to make clinical decisions.

ETHICS AND DISSEMINATION

Formal ethical approval is not required in this protocol. We will collect and analyze data based on published studies, and since there are no patients involved in this study, individual privacy will not be under concerns. The results of this review will be disseminated to peer-reviewed journals or submit to related conferences.

PROTOCOL REGISTRATION NUMBER

INPLASY202060058.

A Randomized Double-Blind Placebo-Control Study to Assess the Efficacy and Safety of OLNP-05 Versus Placebo for the Treatment of Subjects with Premature Ejaculation

Premature ejaculation (PE) is one of the foremost sex-related health problems among men. The global occurrence ranges from 20% to 30%, according to various studies. PE has a great impact on the men's quality of life, with deleterious effects such as embarrassment, frustration, and feeling of incompetence. Considering the necessity of treatment of PE, this study was planned to compare the efficacy and safety of OLNP-05 versus placebo for treating subjects suffering from PE. In this randomized clinical study, 60 men with PE were enrolled and randomly assigned to receive either OLNP-05 or placebo one capsule twice daily for a period of 8 weeks. Subjects were evaluated during visits on day 1, day 28, and day 56. Mean change from baseline in intravaginal ejaculatory latency time (IELT), improvement in premature ejaculation profile (PEP), and Clinical Global Impression-Improvement scale (CGI-I) were used to assess the efficacy of treatment. P-value <.05 was considered significant. At the end of the treatment, the improvement in IELT score in the OLNP-05 group was remarkably higher than the placebo. Subjects in the OLNP-05 treatment group also reported significantly greater improvement in PEP subscale score. Majority of OLNP-05-treated subjects were found to be in the "much improved" category as per CGI-I assessment. The result confirms the safety and efficacy of OLNP-05, therefore suggesting that OLNP-05 may be a safe and effective intervention for the management of PE. Trial registration: Clinical Trials Registry India (Registration No: CTRI/2017/08/009226, 02/08/2017).

The heart rate recovery is impaired in participants with premature ejaculation

Premature ejaculation (PE) is one of the most common sexual disorders in men. Excessive activity of the sympathetic nervous system is considered as one of the pathological mechanisms of PE. Heart rate recovery (HRR) is a noninvasive and easily applicable method for evaluating autonomic functions. We aimed to investigate the relationship between PE and HRR. This cross-sectional study included 42 consecutive patients with lifelong PE and 98 healthy volunteers. All participants underwent stress tests according to age-dependent target heart rates outlined in the Bruce protocol. When the maximal heart rate was reached in the stress test, intensive exercise was terminated and electrocardiographic records were obtained for 3 min in the cool-down period. The HRR indices were calculated by subtracting the heart rate at first, second and third minutes from the maximal HR. The two groups were similar in terms of age, body mass index, serum glucose and lipid parameters. HRR indices were significantly lower in the PE group compared with the control group (p < .05 for all). Common factors that affect equilibrium of sympathetic and parasympathetic nervous systems may be involved in the PE and abnormal HRR etiopathogenesis. The cause-and-effect relationship can be more clearly demonstrated with large-scale, prospective studies.

Association of NE, leptin, and 5-HT with electrophysiological parameters in patients with primary premature ejaculation

OBJECTIVE

To investigate the possible role of serum norepinephrine (NE), leptin, and 5-hydroxytryptamine (5-HT) and their correlations with sympathetic skin response located in the penis (PSSR) in primary premature ejaculation (PPE).

METHODS

We compared the serum level of NE, leptin, and 5-HT, intravaginal ejaculatory latency time (IELT) and the premature ejaculation diagnostic tool (PEDT) scores between 57 PPE patients and 42 healthy control men as controls, who were recruited between September 2016 and January 2019. Additionally, the amplitude and latency of PSSR were measured and compared between the two groups.

RESULTS

Compared with healthy men, both leptin and NE increased significantly in PPE patients (P = .003, P = .005), while serum 5-HT remarkably decreased (P = .002). Serum leptin, NE, and 5-HT were significantly correlated with the diagnosis of PPE, PSSR amplitude, and latency. Moreover, compared with single serum indicator, NE/5-HT and leptin/5-HT had a stronger correlation with both PSSR amplitude (r = .8377, P < .001; r = .9323, P < .001, respectively) and latency (r = -.8058, P < .001; r = -.8901, P < .001, respectively).

CONCLUSION

Significant differences in leptin, NE, and 5-HT are observed between PPE patients and the controls, which supports the hypothesis of hyperactive sympathetic nerve system (SNS) in PPE. Additionally, leptin/5-HT ratio may serve as an ideal indicator for reflecting SNS activity and predicting treatment response in PPE patients in the future.