Gene Polymorphisms Affecting Erectile Dysfunction

Erectile dysfunction and sleep related bruxism: An exploratory review of an improbable association

The World Health Organization recognizes sexual health as not merely the absence of disease, but a state of physical, mental, and social well-being in relation to one's sexuality. Achieving sexual satisfaction is pivotal for many individuals, as it significantly contributes to their quality of life. Among various sexual disorders, erectile dysfunction (ED) is notably prevalent, affecting an estimated 10-20 million men in the United States alone. This condition impacts not just the person experiencing it but also significantly influences their intimate connections with partners. Although the causes of ED are multifactorial, recent research highlights a compelling association between sleep disorders, such as sleep deprivation, obstructive sleep apnea (OSA), and insomnia, and the incidence of ED. Furthermore, engaging in night work has been observed to exacerbate the risk of developing ED. One common sleep disorder, sleep related bruxism (SRB), despite its prevalence, has not generally been associated with ED. However, there is some interesting evidence hinting at a potential relationship, including a few studies reporting a high prevalence of ED in individuals with SRB. This review delves into the epidemiological, etiological, and mechanistic links between ED and SRB, aiming to uncover potential intersections between these two conditions. These insights could pave the way for innovative research avenues, possibly exploring treatments like vasodilation medication, that might concurrently address both ED and SRB.

Association of the VEGF 2578C>A Polymorphism With Metabolic Syndrome and Erectile Dysfunction

Accumulating evidence suggests a link between vascular endothelial growth factor (VEGF), erectile dysfunction (ED), and metabolic syndrome (Mets), possibly because VEGF can alter the physiological pathways involved in the regulation of endothelial cell proliferation. This study aimed to investigate the genetic susceptibility of VEGF 2578C>A polymorphism to the development of ED and Mets. Collected data included five-item International Index of Erectile Function (IIEF-5), components of Mets, and VEGF 2578C>A polymorphism. A total of 596 subjects from Kaohsiung with a mean age of 55.5 years were enrolled, data collection was done at our hospital. Individuals carrying the VEGF 2578 A allele (CA+AA genotypes) demonstrated a higher prevalence of ED compared to those with the CC genotype, with an adjusted odds ratio (OR) of 1.582 (95% confidence interval [95% CI] = 1.123-2.227, p value = 0.009) in multivariate binary regression analysis. Similarly, individuals carrying the VEGF 2578 A allele showed a higher prevalence of Mets compared to those with the CC genotype, with an adjusted OR of 2.461 (95% CI = 1.491-4.064, p value < 0.001). Furthermore, A allele carriers had significantly lower IIEF-5 scores and a higher number of Mets components compared to those with the C allele (P value < 0.001, respectively). In conclusion, VEGF 2578 A allele carriers are at a greater risk of both Mets and ED, suggesting that the VEGF 2578C>A polymorphism may serve as a common genetic susceptibility factor in the development of both disorders. Further research is warranted to evaluate the mechanisms underlying this association.

Association between MTHFR c.677C>T variant and erectile dysfunction among males attending fertility clinic

Genetic risk factors have been shown to contribute to the development of sexual dysfunction. However, the role of methylenetetrahydrofolate reductase ( MTHFR ) gene variants in the risk of erectile dysfunction (ED) remains unclear. In this study, we recruited 1254 participants who underwent ED assessed by the International Index of Erectile Function-5. The MTHFR c.677C>T variant was also measured by fluorescence polymerase chain reaction (PCR). No significant difference in the genotypic frequency of the MTHFR C677T polymorphism (CC, CT, and TT) was observed between men from the ED and non-ED groups. In addition, on binary logistic regression analysis, both crude and adjusted models showed that the risk of ED was not significantly associated with the C677T polymorphism. Interestingly, a significantly higher frequency of the 677TT polymorphism was found in severe and moderate ED (P = 0.02). The positive correlation between the MTHFR 677TT polymorphism and severe ED was confirmed by logistic regression analysis, even after adjusting for potential confounders (odds ratio [OR] = 2.46, 95% confidence interval [CI] 1.15-5.50, P = 0.02). These findings suggest a positive correlation between the MTHFR 677TT polymorphism and the risk of severe ED. Identification of MTHFR gene polymorphisms may provide complementary information for ED patients during routine clinical diagnosis.

Substance abuse and male sexual dysfunction: what lies beneath?

INTRODUCTION

Substance abuse has become a worldwide health problem, leading to numerous consequences such as social problems among family members, abnormal behavior, adverse health effects, and psychological problems as well as economic consequences.

OBJECTIVES

We sought to assess the relationship between substance abuse and male sexual health.

METHODS

A search was carried out in the following databases: PubMed, MeSH (Medical Subject Headings), Science Direct, Scopus, Cochrane Library, EMBASE, CINAHL, Academic Search Complete, and the Egyptian Knowledge Bank. The following keywords were used to assess the outcomes for relevant associations: illicit drugs, addiction, substance abuse, sexual health, erectile dysfunction, ejaculatory disorders, impotence, orgasm disorders, and sexual performance.

RESULTS

The initial literature search identified a total of 148 articles in all searched databases. After removal of duplicate studies and application of inclusion/exclusion criteria, 75 reported studies were retained for review, including 38 case-control studies and 37 cross-sectional studies. These articles were classified into the following categories according to the type of abused substance addressed: cannabis/marihuana, 16 articles; opioids, 13 articles; heroin, 11 articles; cocaine, 5 articles; tramadol, 6 articles; ketamine, 2 articles; ecstasy, 4 articles; amphetamine, 2 articles; khat, 7 articles; androgen anabolic steroids, 2 articles; and polydrugs, 7 articles. Most of these recruited articles demonstrated a negative impact of the addressed substance on male sexual health, with variable levels.

CONCLUSION

Substance abuse has negative impacts on male sexual health that should be addressed. More studies conducted with proper methodological and statistical approaches, including logistic regression analysis, are needed to predict the effects of specific substances, considering the rapidly growing effects of non-substance-use disorders on male sexual health.

Oral phosphodiesterase type 5 inhibitors and male reproductive potential: an overview

BACKGROUND

Phosphodiesterase type 5 inhibitors (PDE5Is), due to their efficacy and tolerable profile for more than 2 decades,are considered a good addition to the available treatments in patients with erectile dysfunction (ED).

AIM

We sought to assess the possible influence of oral PDE5Is on male human reproduction.

METHODS

A literature review was performed in several databases, including the PubMed/Medline database, Scopus, Cochrane Library, EMBASE, Academic Search Complete, and Egyptian Knowledge Bank databases. The keywords/search terms were "PDE5Is," "sildenafil," "vardenafil," "tadalafil," or "avanafil," combining and crossing them with "male infertility," "semen," "reproductive hormones," or "sperm."

RESULTS

Overall, 101 articles were selected. After removal of duplicates and animal studies, 75 articles were finally subjected to review covering the different items related to male human reproduction, including effects of PDE5Is on different parameters of semen or reproductive hormones, as uses of PDE5Is in cases related to distinctive male factor infertility, such as ED, temporary ED, or ejaculatory failure alongside assisted reproduction (AR) procedures, and ejaculatory dysfunction in spinal cord lesions. We found 26 articles that addressed the direct effects of PDE5Is on semen and reproductive hormonal profiles, 16 in vivo studies and 10 in vitro studies. Oral PDE5Is have in general a stimulatory effect on sperm motility, while other semen parameters and reproductive hormonal profiles showed varied outcomes. Such effects are more pronounced with a long-term daily regimen than with an on-demand regimen. However, it seems that the best-controlled studies suggested no change in the sperm quality of male reproductive potential.

CONCLUSION

Oral PDE5Is have in general stimulatory effects on sperm motility, while other semen parameters and hormone profiles showed varied results. In addition, oral PDE5Is have played a useful role in conditions related to distinctive male factor infertility, such as ED, temporary ED, ejaculatory failure alongside AR, and ejaculatory dysfunction in spinal cord lesions.

Isolation, bioassay and 3D-QSAR analysis of 8-isopentenyl flavonoids from Epimedium sagittatum maxim. as PDE5A inhibitors

BACKGROUND

As known, inhibition of phosphodiesterase 5 (PDE5) has the therapeutic effect on male erectile dysfunction (ED), and the processed folium of Epimedium sagittatum Maxim. (PFES) characterized by 8-isopentenyl flavonoids is a famous herb for treating ED. However, the main flavonoids inhibitory activities, structure-activity relationship (SAR) and signaling pathway have been not systematically studied so that its pharmacodynamic mechanism is unclear.

METHODS

We aimed to initially reveal the PFES efficacy mechanism for treating ED. For the first time, 6 main 8-isopentenyl flavonoids (1-6) from PFES were isolated and identified. Then based on HPLC detection, we proposed a novel method to screen inhibitors among them. We further analyze the three-dimensional quantitative structure-activity relationship (3D-QSAR) for those inhibitors.

RESULTS

The results were verified by cellular effects of the screened flavonoids. Among 6 compounds, Icariin: (1), 2-O''rhamnosylicaridide II (2) and Baohuoside I (3) were identified with significant activities (IC₅₀ = 8.275, 3.233, 5.473 μM). Then 3D-QSAR studies showed that the replacement of C8 with bulky steric groups as isopentenyl, C3 with positive charge groups and C4' with a hydrogen bond acceptor substituent could increase inhibitory effects. In contrast, the substitution of C7 with bulky steric groups or hydrophilic groups tended to decrease the efficacies. And compounds 1, 2, 3 could increase cGMP level and decrease cytoplasmic Ca²⁺ of rat corpus cavernosum smooth muscle cells (CCSMCs)by activating PKG.

CONCLUSION

8-isopentenyl flavonoids could be the main pharmacodynamic substances of PFES in the treatment for ED, and some had significant PDE5A1 inhibitory activities so as to activate cGMP/PKG/Ca²⁺ signaling pathway in CCSMCs, that was related to the substituents at the key sites such as C8, C3, C4' and C7 in the characteristic compounds.