The interaction of serum testosterone levels and androgen receptor CAG repeat polymorphism on the risk of erectile dysfunction in aging Taiwanese men

An evaluation of pharmacological options for Cushing's disease: what are the state-of-the-art options?

INTRODUCTION

Untreated Cushing's syndrome (CS) is associated with significant morbidity and mortality. Cortisol normalization is a key goal to treatment. Pituitary surgery remains the first-line approach for Cushing's disease, but sometimes it is impracticable, unsuccessful, or complicated by recurrence. Medical therapy has been historically considered a palliative. However, in the latest years, interest on this topic has grown due to both the availability of new drugs and the reevaluation of the old, commonly used drugs in clinical practice.

AREAS COVERED

In this article, we will discuss the current options and future directions of medical therapy for CS, aiming at fitting best patients' features. An extensive literature search regarding already approved and investigational principles was conducted (PubMed, ClinicalTrials.gov. Available drugs include inhibitors of ACTH secretion, steroidogenesis inhibitors, and glucocorticoid receptor antagonists; drugs acting at different levels can be also combined in uncontrolled patients.

EXPERT OPINION

Since there is still no standardized pharmacological approach and the superiority of one drug over another has not been established yet in the absence of comparative studies, each time clinicians' choices should be patient-tailored. Age, gender, tumor features, severity of hypercortisolism, comorbidities/complications, rapidity of action, side effects, drug-drug interactions, contraindications, availability, patients' preferences, and costs should be all considered.

Erectile Dysfunction in Young Men: Testosterone, Androgenic Polymorphisms, and Comorbidity With Premature Ejaculation Symptoms

BACKGROUND

The association between erectile dysfunction (ED), free testosterone (T), and androgenic genetic polymorphisms is still unclear. As most studies in the field have focused on older (>40 y.o.) men, data from young men is scarce. In addition, the clinically observed comorbidity between ED and premature ejaculation (PE) has not been explained.

AIM

The aim of the present study was 3-fold: to assess in a sample of young men (1) the association between ED and T; (2) the role of androgenic genetic polymorphisms in the aforementioned association; and (3) comorbidity between ED and PE symptoms.

METHODS

Statistical analyses were performed on a population-based sample of 2,302 Finnish men, (M_age = 26.8 years). Hormone samples were available from 317 men, and genotype information was available from a minimum of 1,144 men depending on genetic locus. For twin analyses, the sample contained 533 male individuals from opposite-sex fraternal twin pairs, 491 identical male individuals (110 complete pairs), 493 male individuals from male fraternal twin pairs (92 complete pairs), and 658 siblings of twins.

OUTCOMES

The main outcome measure includes association between levels of salivary T and ED, main effects of the androgen-related genetic polymorphisms on ED scores. Bivariate twin models of PE and ED were fitted to elucidate possible shared etiology.

RESULTS

We found no significant association between T levels and ED and no significant main effects of the androgenic genetic polymorphisms on ED. We found no evidence suggesting that any of the genetic polymorphisms would moderate the association between T and ED symptoms. We found shared unique environmental influences between PE and ED (r_E = .28).

CLINICAL TRANSLATION

Obtained data suggest that ED has T-independent causes and that any comorbidity between PE and ED is not explained by a set of genes affecting both phenotypes.

STRENGTHS & LIMITATIONS

First, the sample size for both parts of the study was relatively small, which may make some statistical analyses underpowered. Furthermore, as the sample was a population-based sample of relatively young men, the number of clinically relevant ED cases was low. Second, some concerns about T derived from saliva exist because saliva sampling comes with increased risks of error particularly because saliva samples are more vulnerable to contamination.

CONCLUSION

We found no significant association between free T levels, androgenic genetic polymorphisms, and ED in the younger age cohort. Twin analysis suggested a common nonshared environmental component in PE and ED. Zhuravleva1 ZD, Johansson A, Jern P. Erectile Dysfunction in Young Men: Testosterone, Androgenic Polymorphisms, and Comorbidity With Premature Ejaculation Symptoms. J Sex Med 2021;18:265-274.

Genetics and erectile dysfunction: leveraging early foundations for new discoveries

There is considerable interest in understanding the genetics of erectile dysfunction (ED). Since early twin studies that suggested a genetic component to ED, multiple candidate gene studies have identified genetic variants that may be associated with ED. Genome-wide association studies (GWAS) have overcome some of the criticism of the candidate gene approach. Two recent GWAS studies have identified loci near SIM1 that may be associated with ED and have renewed interest in the leptin melanocortin signaling pathway. We review the current literature on the genetic basis of ED by highlighting several candidate genes and genetic variants associated with ED.

Genetic Variation in the Androgen Receptor Modifies the Association Between Testosterone and Vitality in Middle-Aged Men

BACKGROUND

Low vitality is a common symptom of testosterone deficiency; however, clinical trial results remain inconclusive regarding the responsiveness of this symptom to hormone replacement.

AIM

The aim of the present study was to determine if the relationship between circulating testosterone levels and vitality would be moderated by the CAG repeat length in the androgen receptor (AR) gene, which influences the receptor's sensitivity to testosterone.

METHODS

We examined 676 men in the Vietnam Era Twin Study of Aging when they were, on average, 55.4 years old (SD = 2.5). Salivary testosterone levels were measured by using 3 samples collected at waking on 3 nonconsecutive days. The average testosterone level was classified as low, normal, or high based on 1-SD cutoffs. Analyses were conducted using multilevel, mixed linear models, which accounted for the nonindependence of the twin data, and adjusted for the effects of age, ethnicity, BMI, chronic health conditions, depressive symptoms, and sleep quality.

OUTCOMES

Vitality was measured using the 36-item Short Form (SF-36) vitality subscale.

RESULTS

We observed a significant interaction between salivary testosterone and the AR-CAG repeat length. When the repeat length was short, men with low testosterone had significantly lower vitality. As the AR-CAG repeat length increased, the magnitude of the testosterone effect decreased.

CLINICAL TRANSLATION

The observed interaction between testosterone and variation in the AR gene suggests that men with more sensitive ARs, as indicated by a shorter AR-CAG repeat, are more likely to experience symptoms of age-related testosterone deficiency.

STRENGTHS & LIMITATIONS

Strengths of the present study include our use of a large community-based sample, the use of multiple testosterone measurements, and the availability of a comprehensive set of covariates that may impact the association of interest. Limitations include the homogeneous nature of the sample with respect to ethnicity, the brevity of the 36-item Short Form vitality subscale, and our inability to establish change in testosterone levels because of the cross-sectional nature of data.

CONCLUSIONS

The association between testosterone and vitality appears to be clinically meaningful and is in part dependent on variation in the AR gene. Panizzon MS, Bree K, Hsieh T-C, et al. Genetic Variation in the Androgen Receptor Modifies the Association Between Testosterone and Vitality in Middle-Aged Men. J Sex Med 2020;17:2351-2361.

Gene Polymorphisms Affecting Erectile Dysfunction

INTRODUCTION

Erectile dysfunction (ED) is usually developed from psychological, neurological, hormonal, and vascular pathologies or a combination of these factors. However, the possible genetic polymorphisms that might underlie this disorder were not thoroughly investigated.

OBJECTIVES

This review article aimed to assess the possible involvement of gene polymorphisms in men with ED.

METHODS

A systematic review was conducted until January 2020 based on a search of all relevant articles in many electronic sites such as PubMed, Medline Medical Subject Headings, Science Direct, Scopus, Cochrane Library, EMBASE, CINAHL, and Egyptian Knowledge Bank databases with no language restriction. Keywords used to assess the outcome and estimates for relevant associations were sexual health, genes, erectile dysfunction, polymorphisms, and cavernous tissues.

RESULTS

Many genetic studies were carried out to inspect the contribution of different encoded genotypes and ED. Overall, 50 studies were reviewed and were classified as per the type of gene polymorphisms. These studies have investigated 10,174 men with ED compared with 6,891 healthy men as controls. 35 studies were case-controlled, 13 cross-sectional cohort studies, one retrospective study, and one genome-wide association study. So far, the most relevant gene polymorphisms linked with men with ED included endothelial nitric oxide synthase (eNOS), angiotensin-converting enzyme (ACE), androgen receptor (AR) CAG repeat, G-protein β3 (GNB3) subunit, methylenetetrahydrofolate reductase (MTHFR), vascular endothelial growth factor (VEGF), TGFB1, proprotein convertase subtilisin/kexin type 9 (PCSK9), ARG1, DRD2, DRD4, DDAH, and HNF4A genes. Both PROGINS and IGFBP-3 polymorphisms were investigated in only one study each but with irrelevant significance.

CONCLUSIONS

Although several genetic studies exposed the association between different genotypes and men with ED with varied outcomes, such a relationship should not be overlooked. Therefore, more studies should be encouraged to elucidate the exact role, if any, for such association. Mostafa T, Taymour M. Gene Polymorphisms Affecting Erectile Dysfunction. Sex Med 2020;8:561-572.

Longer trinucleotide repeats of androgen receptor are associated with higher testosterone and low oxytocin levels in diabetic premature ejaculatory dysfunction patients

Background

Despite its worldwide high occurrence, the obscurity regarding the description, epidemiology and management of premature ejaculation remains provocative. It is well established that male premature ejaculatory dysfunction is an increasing problem due to spontaneous ejaculation across a variety of general and clinical subjects. The main goal of this study was to determine the relationships between trinucleotide repeats of the androgen receptor (AR), sex steroids, and pituitary hormones with sexual function in men with type 2 diabetes mellitus (DM) and reported with acquired premature ejaculation (PE).

Methods

A total of 150 normal and 250 PE + DM subjects were enrolled in this study. Each subject was invited to fill out an elaborative questionnaire to acquire precise selective information regarding BMI, duration of PE + DM, self-reported Intra-Vaginal Ejaculatory Latency Time (IELT), sexual and mental health status by using the premature ejaculation diagnostic tool (PEDT) and Beck Depression Inventory-II (BDI-II). Pearson's correlation analysis was used to analyze the relationship between clinical, hormonal, and genetic variables. Ward's minimum variance cluster analysis and principal component analysis were used for evaluation of dependence between genetic, clinical, and demographic parameters.

Results

The patients who have the lowest number of (≤21) (CAG)n repeats have higher serum oxytocin levels (114.2 pg/ml; n = 54, 43.2%) than the controls (69.18 pg/ml; n = 22, 17.6%) and the patients with the highest (≥26) number of (CAG)n repeats (62.9 pg/ml; n = 108, 43.2%).On the other hand, patients who have the highest numbers of (CAG)n repeats (≥26) have higher serum testosterone (6.1 ng/ml; n = 108, 43.2% of cohort) lower prolactin (3.01 ng/ml; n = 108, 43.2% of cohort) levels than the controls and patients with the lowest numbers (≤21) of (CAG)n repeats and their TSH (1.53 mIU/L, P < 0.05) levels are lower than those of controls. In the Pearson correlation model, self-estimated IELT demonstrated significantly negative correlation with both (CAG)n and (GCC)n repeats (r = - 0.16, p = 0.0001; r = - 0.19, p = 0.0001) respectively. These repeats have positive correlation with PEDT (r = 0.28, p = 0.0001: r = 0.24, p = 0.0001, whole model) and inversely correlated with BDI-II (r = - 0.25, p = 0.0001).

Conclusion

This study indicates that androgen receptor polymorphism modulates the endocrine effect on ejaculatory reflex and depends strongly on its "cofactors". Moreover, our results also confirmed an association between long tri-nucleotide repeats of androgen receptor, sex steroids, pituitary, and thyroid hormones in relation to  acquired premature ejaculatory dysfunction in diabetic patients. However, endocrine regulation of PE reflex is a complex phenomenon that requires further investigation.

Efficacy of Low-Intensity Extracorporeal Shock Wave Therapy on Men With Chronic Pelvic Pain Syndrome Refractory to 3-As Therapy

Managing patients with chronic pelvic pain syndrome (CPPS) refractory to the traditional 3-As therapy (antibiotics, alpha-blockers, and anti-inflammatories) is a challenging task. Low-intensity extracorporeal shock wave therapy (LI-ESWT) was recently reported to be able to improve pain, urinary symptoms, and even sexual function by inducing neovascularization and anti-inflammation, reducing muscle tone, and influencing nerve impulses. This study evaluates whether combined treatment with LI-ESWT can restore clinical ability and quality of life (QoL) in patients refractory to 3-As therapy. This was an open-label, single-arm prospective study. Patients with CPPS without more than a 6-point decrease in the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) total score under the maximal dosage of 3-As therapy were enrolled. LI-ESWT treatment consisted of 3,000 shock waves administered once weekly for 4 weeks. The NIH-CPSI, visual analog scale (VAS) score, International Prostate Symptom Score (IPSS), and the five-item version of the International Index of Erectile Function (IIEF-5) were used to evaluate efficacy at 1, 4, and 12 weeks after LI-ESWT. Thirty-three patients were enrolled in this study. After LI-ESWT treatment, 27 of the 33 patients (81.82%) had a successful response to LI-ESWT, with a decrease of 3.29 and 5.97 in the VAS score and total IPSS at the 3-month follow-up. Waist circumference was the only significant predictor of a successful response to LI-ESWT. LI-ESWT can serve as a salvage therapy for patients with CPPS refractory to traditional 3-As therapy. Further studies are needed to determine an adequate therapeutic protocol and important predictors in patients with different CPPS etiologies.

Low-Intensity Extracorporeal Shockwave Therapy Can Improve Erectile Function in Patients Who Failed to Respond to Phosphodiesterase Type 5 Inhibitors

Managing patients with erectile dysfunction (ED) who failed to respond to phosphodiesterase type 5 inhibitors (PDE5is) is a challenging task. Recently, low-intensity extracorporeal shockwave therapy (LI-ESWT) was reported to improve ED by enhancing perfusion of the penis. The current study was performed to evaluate whether combined treatment with LI-ESWT and PDE5is can restore erectile function in patients who failed to respond to PDE5is alone. This was an open-label single-arm prospective study. ED patients with an erection hardness score (EHS) ≦2 under a maximal dosage of PDE5is were enrolled. Sociodemographic information and detailed medical history were recorded. LI-ESWT treatment consisted of 3,000 shockwaves once weekly for 12 weeks. All patients continued their regular PDE5is use. The EHS and the 5-item version of the International Index of Erectile Function (IIEF-5) were used to evaluate the change in erectile function 1 and 3 months after LI-ESWT. A total of 52 patients were enrolled. After LI-ESWT treatment, 35 of the 52 patients (67.3%) could achieve an erection hard enough for intercourse (EHS ≧ 3) under PDE5is use at the 1-month follow-up. Initial severity of ED was the only significant predictor of a successful response (EHS1: 35.7% vs. EHS2: 78.9%, p = .005). Thirty-three of the 35 (94.3%) subjects who responded to LI-ESWT could still maintain their erectile function at the 3-month follow-up. LI-ESWT can serve as a salvage therapy for ED patients who failed to respond to PDE5is. Initial severity of ED was an important predictor of a successful response.

Lower SHBG level is associated with higher leptin and lower adiponectin levels as well as metabolic syndrome, independent of testosterone

In addition to testosterone (T), the emerging role of sex hormone-binding globulin (SHBG) in pathogenesis of metabolic syndrome (MetS) has been noted recently. However, reports of associations with serum adipocytokine levels are still limited. Therefore, we conducted this study to evaluate whether serum T and SHBG levels are independent predictors for the risk of MetS that are associated with adiponectin and leptin levels in 614 Taiwanese men over 40 years old collected from a free health screening. Subjects in the lowest quartile of TT and SHBG levels are exposed to a 1.58 and 3.22 times risk of developing MetS, as compared to those in the highest quartile of TT and SHBG levels. However, SHBG retains its significance independent of TT as a MetS risk predictor, but not vice versa. In addition, SHBG was significantly correlated with both adiponectin and leptin levels even after adjusting for TT levels. In conclusion, SHBG served as a major predictor for the risk of MetS and was correlated with serum adiponectin and leptin levels that are independent of T. Further studies are needed to elucidate the true role of SHBG in the pathogenesis of MetS and possible mechanisms associated with serum adiponectin and leptin levels.

Influence of Androgen Receptor Gene CAG and GGC Polymorphisms on Male Sexual Function: A Cross-Sectional Study

Background. No study has assessed the possible involvement of GGC androgen receptor (AR) polymorphism in sexual function. Our aim is to evaluate the association between CAG and GGC AR polymorphisms in this function. Methods. We retrospectively examined eighty-five outpatients. Clinical, biochemical, and genetic parameters were considered. Sexual assessment was performed using the International Index of Erectile Function (IIEF) which evaluates erectile function (EF), orgasmic function (OF), sexual desire (SD), intercourse satisfaction (IS), and overall satisfaction (OS). Results. In the whole sample, CAG repeats were inversely correlated with EF, OF, and total IIEF-15 score, whereas GGC tracts did not show any significant correlation with sexual function. CAG relationship with IIEF items retained significance only in the eugonadal but not in the hypogonadal cohort. On the other hand, GGC tracts were not found to be significantly correlated with IIEF variables in either eugonadal or hypogonadal subjects. In eugonadal subjects, logistic regression pointed out that a higher number of CAG triplets were associated with lower values of EF, OF, SD, OS, and total IIEF independently from other confounders. Conclusions. GGC polymorphism seems not to exert any influence on sexual function, whereas CAG polymorphism appears to affect sexual parameters only in eugonadal subjects.