Method and design of drug treatment research of subjective premature ejaculation in men differs from that of lifelong premature ejaculation in males: proposal for a new objective measure (part 1)

The rs6296 polymorphism in the 5-HT1b receptor in Dutch men with lifelong premature ejaculation: a genetic case-control association study

BACKGROUND

Lifelong premature ejaculation (LPE) is a rare sexual condition believed to be caused by genetic neurobiological disorders.

AIM

In this study we sought to evaluate the genetic association between the rs6296 polymorphism of the 5-HT1b receptor and intravaginal ejaculation latency times (IELTs) in men with LPE compared with men in a control group.

METHODS

This study was a prospective observational genetic case-control association study. The LPE definition of the International Society for Sexual Medicine (ISSM) 2013 was used. Patients were recruited in 2005-2009 while attending the department of Neurosexology, HagaZiekenhuis, the Netherlands. We obtained IELTs with the stopwatch method. Polymerase chain reaction (PCR) was used for genotyping rs6296. A randomly selected group of European Caucasian men from the 1000GENOMES project was used as a control group.

OUTCOMES

Study outcomes included results of comparisons of analysis of variance (ANOVA) tests between genotypes and IELTs in study participants, genotypes of cases and controls determined with the chi-square test, and expressions of allelotype- and genotype-specific risks for LPE determined with odds ratios.

RESULTS

In total, 67 men with LPE were included in this study. The geometric mean (SD) IELT was 32.0 (27.4) seconds and was non-normally distributed. Genotype frequencies consisted of 29 (43.3%) GG, 31 (46.3%) GC, and 7(10.4%) CC individuals in the LPE group. Log-transformed IELTs were not statistically significant (per ANOVA tests) in men with GG, GC, or CC genotypes (P = .54). Genotype frequencies consisted of 16 (6.6%) GG; 93 (38.8%) GC, and 131 (54.6%) CC individuals in the control group (n = 240). Significant differences were found when comparing allele (P = 1.02e-17) and genotype (P = 3.22e-16) frequencies in cases and controls using a chi-square test. A statistically significant increased risk for LPE was found for carriers of the G allele (OR 5.62; 95% CI 4.13-9.42). Statistically significant risks were also found for the CG genotype (OR 6.24; 95% CI 2.63-14.77) and the GG genotype (OR 33.92; 95% CI 12.79-89.93).

CLINICAL IMPLICATIONS

By investigating polymorphisms in target genes the neuro-pathophysiology of LPE could be further elaborated, potentially leading to more effective treatment.

STRENGTHS AND LIMITATIONS

This is to our knowledge the first study investigating rs6296 with regard to LPE. By using a strict definition for LPE (ISSM 2013) and using the stopwatch method for measuring IELTs, bias in selection of true LPE patients will be relatively low. This study is limited by a relatively small study population and the lack of IELT data in the control group.

CONCLUSIONS

This study shows a genetic association in rs6296 in men with LPE compared with healthy controls. This result warrants attempted replication in future studies.

Possible Pathophysiological Roles of Neurotransmitter Systems in Men With Lifelong Premature Ejaculation: Protocol for a Scoping Review

BACKGROUND

Lifelong premature ejaculation (LPE) is a rare sexual condition believed to be caused by genetic neurobiological disorders. In the field of LPE, 2 main types of research have been conducted: direct genetic research and pharmacotherapeutic interference of neurotransmitter systems that can relieve the symptoms of LPE in male patients.

OBJECTIVE

We aim to provide an overview of studies on neurotransmitter systems as the pathophysiological cause of LPE by investigating direct genetic research or pharmacotherapeutic interference that relieves the main symptom of LPE in male patients.

METHODS

This scoping review will use the PRISMA-ScR tool (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews). In addition, this study will use a peer-reviewed search strategy. Systematic searches will be conducted using 5 scientific databases (Cochrane Database of Systematic Reviews, PubMed or MEDLINE, Cumulative Index to Nursing and Allied Health Literature [CINAHL], EMBASE, and Epistemonikos). Additionally, pragmatic searches for relevant information in gray literature databases will be performed. Two reviewers will independently include relevant studies in a 2-stage selection strategy. Finally, data will be extracted from the studies and charted to summarize relevant study characteristics and key findings.

RESULTS

As of July 2022, we completed the preliminary searches according to the PRESS 2015 guidelines and started to determine the final search terms that we will use in all selected 5 scientific databases.

CONCLUSIONS

This scoping review protocol is the first to focus on neurotransmitter pathways in LPE by combining the results from the genetic and pharmacotherapy studies. The results could help identify potential research gaps or target candidate proteins and neurotransmitter pathways in LPE for further genetic research.

TRIAL REGISTRATION

Open Science Framework 10.17605/OSF.IO/JUQSD; https://osf.io/juqsd.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/41301.

Current and emerging treatment options for premature ejaculation

Premature ejaculation (PE) is a prevalent male sexual dysfunction. Current standard treatment regimens include behavioural therapies, topical anaesthetics, dapoxetine and other selective serotonin reuptake inhibitors (SSRIs). Most of the pharmacotherapeutic options target neurotransmitters (such as serotonin and oxytocin) that have a role in the ejaculation mechanism. However, these treatments are mildly effective and only provide a temporary delay in the ejaculation latency time, and PE recurs when the treatment is stopped. Thus, a treatment for PE is urgently needed and research is ongoing to find the ideal PE therapy. The efficacy and safety of topical anaesthetics and SSRIs in delaying ejaculation have been confirmed in many well-designed controlled trials. Both preclinical and clinical studies on new-generation SSRIs are ongoing. Moreover, promising results came from clinical trials in which the efficacy of on-demand PE therapies targeting neurotransmitters other than serotonin, such as α1-adrenoceptor antagonists and oxytocin antagonists, was assessed. Surgical intervention and neuromodulation have been proposed as potential treatment options for PE; however, current PE guidelines do not recommend these treatments owing to safety concerns.

Erectile dysfunction and premature ejaculation: a continuum movens supporting couple sexual dysfunction

PURPOSE

The specific underlying mechanisms supporting the association between erectile dysfunction (ED) and premature ejaculation (PE) are still not completely clarified. To summarize and discuss all available data supporting the relationship between PE and ED.

METHODS

A comprehensive narrative review was performed. In addition, to better clarify the specific factors underlining ED and PE, a meta-analytic approach of the selected evidence was also performed. In particular, the meta-analytic method was selected in order to minimize possible sources of bias derived from a personal interpretation of the data.

RESULTS

Current data confirm the close association between ED and PE and the bidirectional nature of their relationship. In particular, PE was associated with a fourfold increased risk of ED independently of the definition used. In addition, the risk increased in older patients and in those with lower education, and it was associated with higher anxiety and depressive symptoms. Conversely, ED-related PE was characterized by lower associations with organic parameters such as diabetes mellitus, arterial hypertension, dyslipidemia and with smoking habit. Finally, when ED was defined according to the International Index of Erectile Function questionnaire, the presence of a stable relationship increased the risk.

CONCLUSIONS

ED and PE should be considered in a dimensional prospective way considering the possibility that both clinical entities can overlap and influence each. Correctly recognizing the underlying factors and sexual complaint can help the clinician in deciding the more appropriate diagnostic and therapeutic work-up.

Self-Reported Shorter Than Desired Ejaculation Latency and Related Distress-Prevalence and Clinical Correlates: Results From the European Male Ageing Study

BACKGROUND

Few data have looked at the occurrence and clinical correlates of self-reported shorter than desired ejaculation latency (rapid ejaculation, RE) and its related distress in the general population.

AIM

To determine the prevalence and clinical correlates of self-reported RE and RE- related distress in middle age and older European men.

METHODS

Subjects were recruited from population samples of men aged 40-79 years across 8 European centers.

OUTCOMES

Self-reported RE and its related distress were derived from the European male Aging Study (EMAS) sexual function questionnaire (EMAS-SFQ). Beck's depression Inventory (BDI) was used for the quantification of depressive symptoms, the Short Form 36 health survey (SF-36) for the assessment of the quality of life, the International Prostate Symptom Score (IPSS) for the evaluation of lower urinary tract symptoms.

RESULTS

About 2,888 community dwelling men aged 40-79 years old (mean 58.9 ± 10.8 years) were included in the analysis. Among the subjects included, 889 (30.8%) self-reported RE. Among them, 211 (7.3%) claimed to be distressed (5.9% and 1.4% reported mild or moderate-severe distress, respectively). Increasing levels of RE-related distress were associated with a progressive worse sexual functioning, higher risk of ED and with couple impairment, along with a higher prevalence of depressive symptoms (all P < 0.05). Furthermore, a worse quality of life and higher IPSS score were associated with RE-related distress (all P < 0.05). The aforementioned results were confirmed even when patients using drugs possibly interfering with ejaculation or those without a stable relationship were excluded from the analysis.

CLINICAL IMPLICATIONS

RE is a frequent condition in men from the general population; however, its related distress is relatively modest. Nonetheless, men with any degree of self-reported RE show increasing levels of depression, worse quality of life and worse couple satisfaction.

STRENGTHS & LIMITATIONS

This is the first study estimating the prevalence of self-reported RE and its related distress, along with their biological and psychological correlates, in a population sample of European middle age and older men. However, is should be recognized that the diagnosis of RE was derived from patient reports and not supported by Intra-ejaculatory-Latency-Time (IELT) measurements.

CONCLUSION

Self-reported RE is relatively common in European men aged more than 40 years. The reported limited RE-related distress may explain the relatively low number of medical consultations for RE. RE-related distress is associated with worse sexual function, couple impairment, and more LUTS resulting in a worse quality of life and mood disturbances. Corona G, Rastrelli G, Bartfai G, et al. Self-Reported Shorter Than Desired Ejaculation Latency and Related Distress-Prevalence and Clinical Correlates: Results From the European Male Ageing Study. J Sex Med Rev 2021;18:908-919.

Redefining a sexual medicine paradigm: subclinical premature ejaculation as a new taxonomic entity

Premature ejaculation (PE) and poor ejaculatory control are multidimensional sexual symptoms estimated to affect almost one-third of men, severely impairing the overall quality of life of patients and their partners. However, patients who do not completely fulfil the definition criteria for PE rarely receive a diagnosis or adequate treatment, with the risk of subsequent progression from initial, subclinical symptoms to clinically overt PE, frequently with other sexual comorbidities. Thus, the current definitions of PE warrant review, in order to consider and propose a new taxonomy encompassing other unaddressed, crucial clinical aspects of PE. These newly proposed criteria include the recommendation for a primary screening for erectile dysfunction (ED), as PE and ED can be comorbid in up to 50% of patients but have never before been considered as a unified clinical entity. In order to facilitate clinical practice and improve clinical management of men with PE and comorbid conditions, we propose and define the new taxonomic clinical entities of subclinical PE (SPE) and loss of control of erection and ejaculation (LCEE). Application of these diagnoses to men who meet the criteria for SPE and/or LCEE, but not the overt conditions, could improve access to treatment for these patients and reduce progression to the more serious clinical disorder.

Pharmacological management of male sexual dysfunction

Male sexual disorders, which are the target of clinical treatment, can be largely divided into erectile dysfunction (ED), ejaculation disorder, infertility, sexual desire disorder, hypogonadism, and other diseases related to penile structure changes, such as Peyronieʼs disease. Current approaches to ED treatment for most men are based on pharmacotherapy. Pharmacotherapy has evolved since the introduction of papaverine and phenoxybenzamine in the early 1980s. Sildenafil, a phosphodiesterase type 5 inhibitor (PDE5I), was the first approved drug for ED. Currently, PDE5Is are the most widely prescribed drugs and have an overall efficacy of 60% to 80% in all categories of ED. Most drugs used in ED are peripheral agents that act on the penis. If a combined treatment with a central nervous system agent and peripheral agents is possible, it may be an effective treatment strategy with higher efficacy. Premature ejaculation (PE) is the most frequent ejaculatory disorder. The absence of a consensus on the definition of PE has served as an obstacle in the investigation of its prevalence and the effectiveness of treatment strategies. Although the etiology of PE is unknown, some biological and psychological hypotheses, including anxiety, penile hypersensitivity, and 5-hydroxytryptamine receptor dysfunction have been suggested. Dapoxetine hydrochloride, a short-acting selective serotonin reuptake inhibitor, was approved for on-demand treatment of PE. Off-label use of antidepressants, topical anesthetic agents, tramadol, and PDE5Is is now available as a pharmacological option. The aim of this review is to describe recent advancements in the pharmacological treatment of male sexual disorders, especially focused on ED and PE.