GWAS Identifies Risk Locus for Erectile Dysfunction and Implicates Hypothalamic Neurobiology and Diabetes in Etiology

Genetically proxied intestinal microbiota and risk of erectile dysfunction

BACKGROUND

The interaction between intestinal microbiota and erectile dysfunction (ED) is less investigated. This study was performed to explore the association between intestinal microbiota and ED.

METHODS

In this two-sample Mendelian randomization (MR) study, genetic variants of gut microbiota were obtained from MiBioGen consortium containing 18,340 individuals. Six methods including inverse variance weighting (IVW), MR-Egger, weighted median, maximum likelihood, MR robust adjusted profile score, and MR pleiotropy residual sum and outlier were used to investigate the causal links between intestinal microbiota and ED. Furthermore, reverse MR analysis was performed to exclude the causal impact of ED on gut microbiota.

RESULTS

As revealed by the IVW estimator, the risks of ED were raised by genetically proxied Lachnospiraceae (OR: 1.27), Lachnospiraceae NC2004 group (OR: 1.17), Oscillibacter (OR: 1.20), Senegalimassilia (OR: 1.32) (All P < 0.05) and Tyzzerella-3 (OR: 1.14, P < 0.05). It was observed that Ruminococcaceae UCG013 exerted protective effect against ED (OR: 0.77, P < 0.05). These results were consistent with other estimators in sensitivity analyses. In reverse MR analyses, genetic liability to ED did not alter the abundances of Lachnospiraceae, Lachnospiraceae NC2004 group, Oscillibacter, Senegalimassilia, Tyzzerella-3, and Ruminococcaceae UCG013 (All P > 0.05). No heterogeneity and pleiotropy were detected by Cochran's Q-test, MR-Egger, and global test (All P > 0.05).

CONCLUSIONS

This study provided novel evidence that genetically proxied Lachnospiraceae, Lachnospiraceae NC2004 group, Oscillibacter, Senegalimassilia, Tyzzerella-3, and Ruminococcaceae UCG013 had potentially causal effects on ED. Further studies are needed to clarify the biological mechanisms linking intestinal microbiota to ED.

Association between atorvastatin and erectile dysfunction: a comprehensive analysis incorporating real-world pharmacovigilance and Mendelian randomization

Background

Atorvastatin is a commonly prescribed medication for the prevention of cardiovascular diseases. Recent observational studies have suggested a potential association between atorvastatin use and the occurrence of Erectile Dysfunction (ED). In this study, we aimed to explore the relationship between atorvastatin and ED using real-world data from the FAERS database and employed Mendelian randomization to assess causality.

Methods

To evaluate the disproportionality of atorvastatin in relation to ED, we conducted several pharmacovigilance analyses, including odds ratio (ROR), proportional reporting ratio (PRR), Bayesian Confidence propagation neural network (BCPNN), and gamma-Poisson contractile apparatus (GPS). Additionally, we employed Mendelian randomization to investigate the causal relationship between atorvastatin and ED.

Results

Pharmacovigilance disproportionality analysis revealed a significant association between atorvastatin and ED, as indicated by the following results: ROR [3.707078559, 95% CI (3.33250349, 4.123756054)], PRR [3.702969038, χ2 (669.2853829)], IC [1.870490139, IC025 (1.702813857)], and EBGM [3.656567867, EBGM05 (3.28709656)]. Furthermore, the two-sample Mendelian randomization analysis provided evidence supporting a causal relationship between atorvastatin use and ED, with an inverse variance weighted estimate of β = 3.17 (OR = 23.91, p = 0.02 < 0.05).

Conclusion

Based on comprehensive analyses incorporating pharmacovigilance and Mendelian randomization, our findings suggest that atorvastatin use is associated with an increased risk of ED and indicate a causal relationship. These results emphasize the importance of considering potential adverse effects, such as ED, when prescribing atorvastatin for cardiovascular disease prevention. Further research and clinical monitoring are warranted to better understand the underlying mechanisms and develop appropriate strategies to mitigate this side effect.

Insights into modifiable risk factors of erectile dysfunction, a wide-angled Mendelian Randomization study

INTRODUCTION

The causal association between modifiable risk factors and erectile dysfunction (ED) remains unclear, which hinders the early identification and intervention of patients with ED. The present study aimed to clarify the causal association between 42 predominant risk factors and ED.

METHODS

Univariate Mendelian Randomization (MR), multivariate MR, and mediation MR analyses were used to investigate the causal association between 42 modifiable risk factors and ED. Combined results were pooled from two independent ED genome-wide association studies to verify the findings.

RESULTS

Genetically predicted body mass index (BMI), waist circumference, trunk fat mass, whole body fat mass, poor overall health rating, type 2 diabetes, basal metabolic rate, adiponectin, cigarette consumption, insomnia, snoring, hypertension, stroke, ischemic stroke, coronary heart disease, myocardial infarction, heart failure, and major depressive disorder were found to increase the risk of ED (all P < 0.05). Additionally, genetic liability to higher body fat percentage and alcohol consumption were suggestively associated with an increased risk of ED (P < 0.05 and adjusted P > 0.05). Genetic predisposition to higher sex hormone-binding globulin (SHBG) levels could decrease the risk of ED (P < 0.05). No significant association was detected between lipid levels and ED. Multivariate MR identified type 2 diabetes, basal metabolic rate, cigarette consumption, hypertension, and coronary heart disease as risk factors for ED. The combined results confirmed that waist circumference, whole body fat mass, poor overall health rating, type 2 diabetes, basal metabolic rate, adiponectin, cigarette consumption, snoring, hypertension, ischemic stroke, coronary heart disease, myocardial infarction, heart failure, and major depressive disorder could increase the risk of ED (all P < 0.05), while higher SHBG decreased the risk of ED (P = 0.004). There were suggestive significances of BMI, insomnia, and stroke on ED (P < 0.05 and adjusted P > 0.05).

CONCLUSION

This comprehensive MR study supported the causal role of obesity, type 2 diabetes, basal metabolic rate, poor self-health rating, cigarette and alcohol consumption, insomnia and snoring, depression, hypertension, stroke, ischemic stroke, coronary heart disease, myocardial infarction, heart failure, SHBG, and adiponectin in the onset and development of ED.

A Mendelian randomization study on causal effects of leisure sedentary behavior on the risk of erectile dysfunction

BACKGROUND

Erectile dysfunction has been associated with leisure sedentary behavior in several epidemiological and observational studies. However, the interpretation of these findings is difficult due to residual confounding or reverse causality.

OBJECTIVES

To explore the causal association between leisure sedentary behavior and erectile dysfunction, and to explore the underlying mechanism using Mendelian randomization.

MATERIALS AND METHODS

In the present study, publicly available large-scale genome-wide association studies of leisure sedentary behaviors (television watching, computer use, and driving), erectile dysfunction, sex hormones (total testosterone, bioactive testosterone, estradiol, follicle-stimulating hormone, luteinizing hormone, prolactin, and sex hormone binding globulin), biomarkers of endothelial function (C reactive protein, E-selectin, and matrix metalloproteinase 7), and psychiatric symptoms (depression and anxiety) were used to perform two-sample Mendelian randomization analyses. The inverse variance weighting method was the main method used to estimate the association, and sensitivity analyses were also performed.

RESULTS

A greater risk of erectile dysfunction was significantly associated with a higher genetic susceptibility to leisure computer usage (odds ratio = 3.57; 95% confidence interval = 1.78-7.16; p < 0.001). No evidence was obtained to suggest that watching television or driving for leisure increased the risk of erectile dysfunction. No association was found between computer use and depression, anxiety, C reactive protein, E-selectin, matrix metalloproteinase 7, or other sex hormones, with the exception of follicle-stimulating hormone levels (odds ratio = 0.29; 95% confidence interval = 0.12-0.69; p = 0.01). No indication of heterogeneity or pleiotropy was identified by sensitivity analysis.

DISCUSSION

Extended computer usage for leisure raised the likelihood of developing erectile dysfunction, which may be associated to lower follicle-stimulating hormone levels; however, the role of endothelial dysfunction and psychological disorders in the development of erectile dysfunction should not be underestimated. Moderate physical activity may help to correct the dysfunction.

CONCLUSION

The present study offered substantial evidence for a positive causal association between computer use and the risk of erectile dysfunction. However, a definitive causal association needs to be established by further research.

The association between serum 25-hydroxyvitamin D levels and erectile dysfunction: a two-sample Mendelian randomization analysis

Considering that vascular endothelial cell dysfunction is the pathological basis of erectile dysfunction (ED), and recognizing the beneficial effects of 25-hydroxyvitamin D (25(OH)D) on vascular endothelial cell protection, the researchers diligently investigated the causal relationship between serum 25(OH)D levels and ED. However, inconsistent clinical evidence has left the association between serum 25(OH)D levels and ED unclear. The objective of this work was to employ Mendelian randomization (MR) analysis to ascertain the potential causal relationship between serum 25(OH)D levels and ED. We conducted a two-sample MR analysis utilizing data from publicly available genome-wide association studies (GWASs). The primary analysis method for the MR analysis was the inverse-variance weighted (IVW) method, supplemented by the MR-Egger and weighted median methods. In addition, we evaluated heterogeneity with Cochran's Q test, assessed pleiotropy using the MR-Egger intercept test, and performed a leave-one-out analysis to identify single-nucleotide polymorphisms (SNPs) with potential effects. Outliers were detected using MR-pleiotropy residual sum and outlier (MR-PRESSO). Genetically predicted serum 25(OH)D levels were not found to be causally associated with ED in IVW method (OR = 1.028, 95% CI = 0.845-1.250, P = 0.785), MR-Egger method (OR = 1.057, 95% CI = 0.782-1.430, P = 0.720), and weighted median method (OR = 1.225, 95% CI = 0.920-1.633, P = 0.165). The results of sensitivity analyses reinforced our conclusion, indicating no evidence of heterogeneity or directional pleiotropy. In summary, our findings do not substantiate a genetic-level causal link between serum 25(OH)D levels and the prevalence of ED. Nonetheless, future research, including larger MR studies, clinical trials, and additional observational studies, is essential to validate and reinforce the outcomes of our present study.

Genetic association of lipid-lowering drug target genes with erectile dysfunction and male reproductive health

Objective

The effect of hypolipidemic drugs on male erectile function is still controversial. This Mendelian randomization (MR) study aimed to explore the potential impact of lipid-lowering drug targets on ED.

Methods

We collected seven genetic variants encoding lipid-lowering drug targets (LDLR, HMGCR, NPC1L1, PCSK9, APOB, APOC3 and LPL) from published genome-wide association study (GWAS) statistics, and performed drug target MR analysis. The risk of ED was defined as the primary outcome, sex hormone levels and other diseases as the secondary outcomes. Mediation analyses were performed to explore potential mediating factors.

Results

The results showed that LDLR, LPL agonists and APOC3 inhibitors were significantly associated with a reduced risk of ED occurrence. APOB inhibitors were associated with an increased risk of ED occurrence. In terms of sex hormone levels, LDLR and LPL agonists were significantly associated with increased TT levels, and HMGCR was associated with decreased TT and BT levels significantly. In terms of male-related disease, MR results showed that LDLR agonists and PCSK9 inhibitors were significantly associated with an elevated risk of PH; HMGCR, NPC1L1 inhibitors were associated with a reduced risk of PCa; and LDLR agonists were significantly associated with a reduced risk of AS and MI; in addition, HMGCR inhibitors were associated with a reduced risk of PCa.

Conclusion

After performing drug-targeted MR analysis, we found that that there was a causal relationship between lipid-lowering drug targets and ED. APOC3, APOB, LDLR and LPL may be new candidate drug targets for the treatment of ED.

Causal associations between prostate diseases, renal diseases, renal function, and erectile dysfunction risk: a 2-sample Mendelian randomization study

Background

Previous observational studies have found a potential link between prostate disease, particularly prostate cancer (PCa), and kidney disease, specifically chronic renal disease (CKD), in relation to erectile dysfunction (ED), yet the causal relationship between these factors remains uncertain.

Aim

The study sought to explore the potential causal association between prostate diseases, renal diseases, renal function, and risk of ED.

Methods

In this study, 5 analytical approaches were employed to explore the causal relationships between various prostate diseases (PCa and benign prostatic hyperplasia), renal diseases (CKD, immunoglobulin A nephropathy, membranous nephropathy, nephrotic syndrome, and kidney ureter calculi), as well as 8 renal function parameters, with regard to ED. All data pertaining to exposure and outcome factors were acquired from publicly accessible genome-wide association studies. The methods used encompassed inverse variance weighting, MR-Egger, weighted median, simple mode, and weighted mode residual sum and outlier techniques. The MR-Egger intercept test was utilized to assess pleiotropy, while Cochran's Q statistic was employed to measure heterogeneity.

Outcomes

We employed inverse variance weighting MR as the primary statistical method to assess the causal relationship between exposure factors and ED.

Results

Genetically predicted PCa demonstrated a causal association with an elevated risk of ED (odds ratio, 1.125; 95% confidence interval, 1.066-1.186; P < .0001). However, no compelling evidence was found to support associations between genetically determined benign prostatic hyperplasia, CKD, immunoglobulin A nephropathy, membranous nephropathy, nephrotic syndrome, kidney ureter calculi, and the renal function parameters investigated, and the risk of ED.

Clinical Implications

The risk of ED is considerably amplified in patients diagnosed with PCa, thereby highlighting the importance of addressing ED as a significant concern for clinicians treating individuals with PCa.

Strengths and Limitations

This study's strength lies in validating the PCa-ED association using genetic analysis, while its limitation is the heterogeneity in study results.

Conclusion

The results of this study suggest a potential link between PCa and a higher risk of ED.

Genetic prediction of modifiable lifestyle factors for erectile dysfunction

Background

The causal relationship between certain lifestyle factors and erectile dysfunction (ED) is still uncertain.

Aim

The study sought to investigate the causal effect of 9 life factors on ED through 2-sample single-variable Mendelian randomization (SVMR) and multivariable Mendelian randomization (MVMR).

Methods

Genetic instruments to proxy 9 risk factors were identified by genome-wide association studies. The genome-wide association studies estimated the connection of these genetic variants with ED risk (n = 223 805). We conducted SVMR, inverse variance-weighting, Cochran's Q, weighted median, MR-Egger, MR-PRESSO (Mendelian Randomization Pleiotropy RESidual Sum and Outlier), and MVMR analyses to explore the total and direct relationship between life factors and ED.

Outcomes

The primary outcome was defined as self or physician-reported ED, or using oral ED medication, or a history of surgery related to ED.

Results

In SVMR analyses, suggestive associations with increased the risk of ED were noted for ever smoked (odds ratio [OR], 5.894; 95% confidence interval [CI], 0.469 to 3.079; P = .008), alcohol consumption (OR, 1.495; 95% CI, 0.044 to 0.760; P = .028) and body mass index (BMI) (OR, 1.177; 95% CI, 0.057 to 0.268; P = .003). Earlier age at first intercourse was significantly related to reduced ED risk (OR, 0.659; 95% CI, -0.592 to -0.244; P = 2.5 × 10-6). No strong evidence was found for the effect of coffee intake, time spent driving, physical activity, and leisure sedentary behaviors on the incidence of ED (All P > .05). The result of MVMR analysis for BMI (OR, 1.13; 95% CI, 1.01 to 1.25; P = .045) and earlier age at first intercourse (OR, 0.77; 95% CI, 0.56 to 0.99; P = .018) provided suggestive evidence for the direct impact on ED, while no causal factor was detected for alcoholic drinks per week and ever smoked.

Clinical implications

This study provides evidence for the impact of certain modifiable lifestyle factors on the development of ED.

Strengths and limitations

We performed both SVMR and MVMR to strengthen the causal relationship between exposures and outcomes. However, the population in this study was limited to European ancestry.

Conclusion

Ever smoked, alcoholic drinks per week, BMI, and age first had sexual intercourse were causally related to ED, while the potential connection between coffee intake, physical activity, recreational sedentary habits, and increased risk of ED needs to be further confirmed.

Causal effects of gut microbiota on the risk of erectile dysfunction: a Mendelian randomization study

Erectile dysfunction ranks among the prevalent sexual disorders in men. Several studies have indicated a potential link between gut microbiota and erectile dysfunction. To validate this potential association, we were to screen statistical data from genome-wide association studies of gut microbiota and erectile dysfunction. p values of less than 1 × 10-5 were set as the threshold for screening instrumental variables that were strongly associated with gut microbiota. At the same time, in order to obtain more convincing findings, we further excluded instrumental variables with possible chain imbalance, instrumental variables with the presence of palindromes, instrumental variables with F-statistics less than 10, and instrumental variables associated with risk factors for erectile dysfunction. Five methods including inverse-variance weighted method, weighted median method, weighted mode, Mendelian randomization egger method and Mendelian randomization pleiotropy residual sum and outlier test were then used to analyse the 2591 instrumental variables obtained from the screening. We identified correlations between six gut microbiota and the risk of erectile dysfunction. The genus Ruminococcaceae UCG-013 exhibited an inverse association with the risk of developing erectile dysfunction (0.79 (0.65-0.97), P = 0.0214). Conversely, the genus Tyzzerella3 (1.13 (1.02-1.26), P = 0.0225), genus Erysipelotrichaceae UCG-003 (1.18 (1.01-1.38), P = 0.0412), genus LachnospiraceaeNC2004group (1.19 (1.03-1.37), P = 0.0191), genus Oscillibacter (1.23 (1.08-1.41), P = 0.0022), and family Lachnospiraceae (1.26 (1.05-1.52), P = 0.0123) demonstrated positive associations with an increased risk of erectile dysfunction. These sensitivity analyses of the gut microbiota were consistent. This study demonstrated a possible causal relationship between gut microbiota and erectile dysfunction risk through Mendelian randomization analysis, providing new potential possibilities for the prevention and treatment of erectile dysfunction.

Potential causal association between aspirin use and erectile dysfunction in European population: a Mendelian randomization study

Background

Aspirin, as one of the most commonly used drugs, possesses a broad spectrum of therapeutic applications. Presently, the potential association between aspirin usage and the risk elevation of erectile dysfunction (ED) remains inconclusive. The objective of this study employing two-sample Mendelian randomization (MR) was to clarify the causal impact of aspirin use on the risk of ED.

Methods

This study incorporated two sets of Genome-Wide Association Study (GWAS) summary statistics, one for aspirin use (46,946 cases and 286,635 controls) and another for ED (6,175 cases and 217,630 controls) in individuals of European ancestry. The inverse-variance weighted (IVW) method was employed as the primary approach, supplemented by MR-Egger, weighted median, weighted mode, and simple mode to estimate the causal effect of aspirin usage on the risk of ED development. To assess pleiotropy, the MR-PRESSO global test and MR-Egger regression were used. Cochran's Q test was adopted to check heterogeneity, and the leave-one-out analysis was performed to confirm the robustness and reliability of the results.

Results

The causal association between genetically inferred aspirin use and ED was found by using inverse variance weighted (OR = 20.896, 95% confidence interval = 2.077-2.102E+2, P = 0.010). The sensitivity analysis showed that no pleiotropy and heterogeneity was observed. Furthermore, the leave-one-out analysis demonstrated that the findings were not significantly affected by any instrumental variables.

Conclusion

The results of this study highlighted the significance of aspirin use as a predisposing factor for ED and provided further evidence supporting the causal association between aspirin utilization and ED within European populations.

The Association between the Gut Microbiota and Erectile Dysfunction

PURPOSE

Explore the causal relationship between the gut microbiota and erectile dysfunction (ED) at phylum, class, order, family, and genus levels, and identify specific pathogenic bacteria that may be associated with the onset and progression of ED.

MATERIALS AND METHODS

The genetic variation data of 196 human gut microbiota incorporated in our study came from the human gut microbiome Genome Wide Association Studies (GWAS) dataset released by the MiBioGen Consortium. The GWAS statistics for ED were extracted from one study by Bovijn et al., which included 223,805 participants of European ancestry, of whom 6,175 were diagnosed with ED. Subsequently, Mendelian randomization (MR) analysis was carried out to explore whether a causal relationship exists between the gut microbiota and ED. Additionally, bidirectional MR analysis was performed to examine the directionality of the causal relationship.

RESULTS

Through MR analysis, we found that family Lachnospiraceae (odds ratio [OR]: 1.27, 95% confidence interval [CI]: 1.05-1.52, p=0.01) and its subclass genus LachnospiraceaeNC2004 group (OR: 1.17, 95% CI: 1.01-1.37, p=0.04) are associated with a higher risk of ED. In addition, genus Oscillibacter (OR: 1.17, 95% CI: 1.02-1.35, p=0.03), genus Senegalimassilia (OR: 1.32, 95% CI: 1.06-1.64, p=0.01) and genus Tyzzerella3 (OR: 1.14, 95% CI: 1.02-1.27, p=0.02) also increase the risk of ED. In contrast, the inverse variance weighted estimate of genus RuminococcaceaeUCG013 (OR: 0.77, 95% CI: 0.61-0.96, p=0.02) suggests that it has a protective effect against the occurrence of ED.

CONCLUSIONS

This study preliminarily identified 6 bacterial taxa that may have a causal relationship with ED, including family Lachnospiraceae, genus Lachnospiraceae NC2004 group, Oscillibacter, Senegalimassilia, Tyzzerella 3 and Ruminococcaceae UCG013. These identified important bacterial taxa may serve as candidates for microbiome intervention in future ED clinical trials.

MESuSiE enables scalable and powerful multi-ancestry fine-mapping of causal variants in genome-wide association studies

Fine-mapping in genome-wide association studies attempts to identify causal SNPs from a set of candidate SNPs in a local genomic region of interest and is commonly performed in one genetic ancestry at a time. Here, we present multi-ancestry sum of the single effects model (MESuSiE), a probabilistic multi-ancestry fine-mapping method, to improve the accuracy and resolution of fine-mapping by leveraging association information across ancestries. MESuSiE uses summary statistics as input, accounts for the diverse linkage disequilibrium pattern observed in different ancestries, explicitly models both shared and ancestry-specific causal SNPs, and relies on a variational inference algorithm for scalable computation. We evaluated the performance of MESuSiE through comprehensive simulations and multi-ancestry fine-mapping of four lipid traits with both European and African samples. In the real data, MESuSiE improves fine-mapping resolution by 19.0% to 72.0% compared to existing approaches, is an order of magnitude faster, and captures and categorizes shared and ancestry-specific causal signals with enhanced functional enrichment.

Effects of obesity-related anthropometric indices and body composition on erectile dysfunction mediated by coronary artery disease: A Mendelian randomization study

BACKGROUND

The causal relationship between obesity-related anthropometric indicators/body composition and erectile dysfunction has not been established in previous observational studies.

METHOD

We screened single nucleotide polymorphisms significantly associated with exposure from genome-wide association studies as instrumental variables (p < 5.0 × 10-8 ). The summary statistics for erectile dysfunction were collected from a genome-wide association study with a sample size of 223,805. Exposure and outcome populations included are of European ancestry. We used univariate and multivariate Mendelian randomization (i) to investigate the causal relationship between genetically predicted obesity-related anthropometric indicators/body composition and erectile dysfunction and (ii) to examine the mediating role of coronary artery disease. Mendelian randomization analysis was conducted using an inverse variance weighted method. A series of sensitivity analyses validated the results of the Mendelian randomization analysis. Causal estimates are expressed as odds ratios with 95% confidence intervals.

RESULTS

Obesity-related anthropometric indicators/body composition were associated with an increased risk of erectile dysfunction in univariate Mendelian randomization analyses. For the 1-SD increase in body mass index, the odds ratio was 1.841 (95% confidence interval: 1.049-1.355, p = 0.006). For the 1-SD increase in waist circumference and hip circumference, the odds ratios were 1.275 (95% confidence interval: 1.101-1.478, p = 0.001) and 1.156 (95% confidence interval: 1.015-1.317, p = 0.009), respectively. The odds ratio for the 1-SD increase in whole body fat mass was 1.221 (95% confidence interval: 1.047-1.388, p = 0.002). For the 1-SD increase in leg fat percentage (left and right), the odds ratios were 1.256 (95% confidence interval: 1.006-1.567, p = 0.044) and 1.285 (95% confidence interval: 1.027-1.608, p = 0.028), respectively. For the 1-SD increase in leg fat mass (left and right), the odds ratios were 1.308 (95% confidence interval: 1.108-1.544, p = 0.001) and 1.290 (95% confidence interval: 1.091-1.524, p = 0.003), respectively. For the 1-SD increase in arm fat mass (left and right), the odds ratios were 1.269 (95% confidence interval: 1.113-1.447, p < 0.001) and 1.254, respectively. Multivariate Mendelian randomization analysis showed that after adjusting for coronary artery disease, some genetic predispositions to obesity-related anthropometric indicators and body composition were still associated with an increased risk of erectile dysfunction. Significant associations were found for waist circumference-erectile dysfunction (odds ratio: 1.218, 95% confidence interval: 1.036-1.432), leg fat percentage (left)-erectile dysfunction (odds ratio: 1.245, 95% confidence interval: 1.035-1.497), leg fat mass (left)-erectile dysfunction (odds ratio: 1.264, 95% confidence interval: 1.051-1.521), arm fat mass (right)-erectile dysfunction (odds ratio: 1.186, 95% confidence interval: 1.024-1.373), and arm fat mass (left)-erectile dysfunction (odds ratio: 1.17, 95% confidence interval: 1.018-1.360). Meanwhile, coronary artery disease mediated the effects of fat on erectile dysfunction, and the proportion of coronary artery disease-mediated cases ranged from 10% to 22%.

CONCLUSION

There is a potential causal relationship between obesity-related anthropometric indicators/body composition and erectile dysfunction. Higher waist circumference, leg fat percentage, and arm fat mass may increase the risk of erectile dysfunction, and coronary artery disease partly mediates this overall effect. Understanding the causal relationship between obesity and erectile dysfunction and the mediating role of coronary artery disease may provide more information for erectile dysfunction intervention and prevention strategies.

The association between lipid parameters and erectile dysfunction: a two-sample Mendelian randomization and case-control study

PURPOSE

Lipid parameters have been shown to have significant predictive value for cardiovascular disease, but few studies have evaluated their correlation with erectile dysfunction (ED) in young men.

METHODS

The case-control study encompassed 186 young ED patients (ages 20-40) and 186 healthy controls. Lipid parameters, including total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), TC/HDL ratio, TG/HDL ratio, and LDL-C/HDL-C ratio, were assessed in all participants. The International Index of Erectile Function (IIEF-5) scores were collected for all participants to evaluate erectile status. Multivariate logistic regression analysis was utilized to appraise the association of lipid-related parameters with ED. Single-nucleotide polymorphisms (SNPs) significantly correlated with lipid parameters (TC, TG, LDL-C, HDL-C) were selected from genome-wide association studies (GWAS) as instrumental variables (IV) (P < 5.0 × 10-8). Summary data for ED was gathered from a GWAS with a sample size of (n = 17,353 cases/28,210 controls). The inverse variance weighted (IVW) method was employed as the primary mendelian randomization (MR) analysis method to assess causal effects. Causal estimates were represented as odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

Results from the case-control study revealed that, when compared with the control group, levels of LDL-C, TG, UA, LDL-C/HDL-C, TG/HDL-C, and TC/HDL-C in the ED group were significantly elevated (P < 0.01), while HDL-C was significantly decreased (P < 0.01) in the ED group. Multivariate logistic regression analysis indicated LDL-C/HDL-C as a risk factor for both the incidence and severity of ED (P < 0.001). Two-sample MR analysis demonstrated no significant causal correlation between lipid parameters-LDL-C (OR, 0.98, 95% CI, 0.88-1.08, P = 0.616), HDL-C (OR, 1.07, 95% CI: 0.96-1.19, P = 0.249), TC (OR, 1.07, 95% CI, 0.96-1.18, P = 0.208), TG (OR, 0.98, 95% CI, 0.80-1.13, P = 0.579) -and an increased risk of ED (all P > 0.05).

CONCLUSIONS

The case-control analysis ascertained a significant association between LDL-C, HDL-C, LDL-C/HDL-C, and ED and its severity. However, results from the MR study do not support a causal role of lipid parameters in ED.

Causal relationship between worry, tension, insomnia, sensitivity to environmental stress and adversity, and erectile dysfunction: a study using Mendelian randomization

BACKGROUND

This study aims to investigate the causal relationship between erectile dysfunction (ED) and psychological states including worry, tension, insomnia, sensitivity to environmental stress and adversity (SESA).

METHOD

This study the used two-sample bi-directional Mendelian randomization (MR) method. The study data was obtained from a pooled dataset of genome-wide association studies (GWAS). The bi-directional MR analysis was performed using inverse variance weighting, weighted median method, and MR-Egger regression analysis to assess the causality between ED and psychological states including worry, tension, insomnia, SESA in terms of odd ratios (OR). The study tested for heterogeneity using the Cochran Q method and for multiple validity using the MR-Egger and MR-PRESSO methods.

RESULTS

In forward MR analysis correlating worry, tension, insomnia, and SESA as exposures, no causal relationship was found between worry or tension and ED (p < 0.05). However, insomnia (p = 0.001, OR = 3.441, 95%CI = 1.593-7.435) and SESA (p = 0.004, OR = 1.804, 95%CI = 1.203-2.701) were found to have a significant causal effect on ED risk. The reverse MR analysis with ED as the exposure did not show any significant correlation (all p > 0.05).

CONCLUSION

Individuals with insomnia and SESA are at higher risk for developing ED. Clinical evaluation should be more thorough for these individuals. Insomnia can be treated simultaneously with psychological counseling to reduce the risk of ED. In addition, there is no evidence to suggest that worry and tension increase the risk of ED.

Specific gut microbiota may increase the risk of erectile dysfunction: a two-sample Mendelian randomization study

Objective

Studies have found that gut microbiota may be associated with the development of erectile dysfunction (ED); however, the exact link between the two remains unclear. This study aimed to elucidate the relationship between the gut microbiota and the risk of ED from a genetic perspective.

Methods

We investigated the relationship between the gut microflora and ED using two-sample Mendelian randomization. GWAS-pooled data for ED were obtained from 223805 participants in Europe. GWAS summary data for ED were obtained from 223805 subjects in Europe and that for the gut microbiota were obtained from 18340 participants in 24 cohorts. We used the inverse-variance weighted (IVW) estimator as the primary method for the preliminary analysis, and the MR-Egger, weighted median (WM), simple model, and weighted model as secondary methods. We used Cochrane's Q-test, to detect heterogeneity, MREgger to detect pleiotropy, and the leave-one-out method to test the stability of the MR results. Ultimately, we genetically predicted a causal relationship between 211 gut microbiota and ED.

Results

A total of 2818 SNPs associated with gut microflora were screened in the ED correlation analysis based on the assumption of instrumental variables. The results of MR analysis showed a causal relationship between the six gut microbes and ED occurrence. The results of the fixed effects IVW method revealed five gut microflora, including Lachnospiraceae (OR, 1.265; P = 0.008), Lachnospiraceae NC2004 group (OR, 1.188; P = 0.019), Oscillibacter (OR, 1.200; P = 0.015), Senegalimassilia (OR, 1.355; P = 0.002), Tyzzerella3 (OR, 1.133; P = 0.022), to be negatively associated with ED. In addition, the IVW method revealed Ruminococcaceae UCG-013 (OR, 0.827; P = 0.049) to be positively associated with ED. Quality control results showed no heterogeneity or horizontal pleiotropy in the MR analysis (P > 0.05).

Conclusions

Six gut microbes were genetically associated with ED; of which, Ruminococcaceae UCG-013 was causally associated with a reduced risk of ED development. Our findings provide a new direction for research on the prevention and treatment of ED; however, the mechanisms and details require further investigation.

Association of high LDL concentrations with erectile dysfunction from a Mendelian randomization study

Lipid metabolism plays a key role in erectile dysfunction. Our purpose was to evaluate the influence of lipid-lowering drugs on erectile dysfunction employing a two-sample Mendelian randomization (MR) study. Genetic instruments were employed to represent the exposure of lipid-lowering drugs. Inverse variance-weighted MR (IVWMR) was employed to calculate the estimation of effects. IVW-MR analysis showed that the positive relationship between the expression of HMGCR and the risk of erectile dysfunction (odds ratio [OR] = 1.27, 95% confidence interval [CI] 1.03-1.57; p = 0.028). No significant relationship was detected between NPC1L1, PSK9 expression and erectile dysfunction. This MR study suggested that HMGCR inhibitors are a more desirable treatment modality for patients with ED.

Type 2 diabetes mellitus and the risk of male infertility: a Mendelian randomization study

Objective

To assess the causal effect of type 2 diabetes mellitus (T2DM) on male infertility (MI) and erectile dysfunction (ED) by Mendelian randomization (MR) analysis.

Methods

Data for T2DM, MI, and ED were obtained from genome-wide association studies (GWAS) involving 298, 957, 73, 479, and 223, 805 Europeans, respectively. We performed univariate MR analysis using MR Egger, Weighted median (WM) and Inverse variance weighted (IVW) methods to assess causal effects among the three. Through the Genotype Tissue Expression (GTEx) database, single-nucleotide polymorphisms (SNPs) that affect the expression levels of T2DM-related genes were located using expression quantitative trait loci (eQTL).

Results

MR analysis showed a significant causal relationship between T2DM and ED (WM, OR: 1.180, 95%CI: 1.010-1.378, P = 0.037; IVW, OR: 1.190, 95%CI: 1.084-1.300, P < 0.001). There is also a significant causal relationship between T2DM and MI (MR Egger, OR: 0.549, 95%CI: 0.317-0.952, P = 0.037; WM, OR: 0.593, 95%CI: 0.400, P = 0.010; IVW, OR: 0.767, 95%CI: 0.600-0.980, P = 0.034). ED may not cause MI (P > 0.05). We also found that rs6585827 corresponding to the PLEKHA1 gene associated with T2DM is an eQTL variant affecting the expression of this gene.

Conclusion

T2DM has a direct causal effect on ED and MI. The level of PLEKHA1 expression suppressed by rs6585827 is potentially associated with a lower risk of T2DM.

Relationship between inflammatory bowel disease and erectile dysfunction: a 2-sample Mendelian randomization study

Background

Observational studies have indicated a high prevalence of erectile dysfunction (ED) among patients with inflammatory bowel disease (IBD), but a definitive causal relationship remains unestablished.

Aim

The primary aim of this study was to assess the potential causal relationship between IBD and ED using Mendelian randomization (MR) analysis.

Methods

We obtained statistical data for 2 subtypes of IBD, ulcerative colitis (UC) and Crohn's disease (CD), as well as for ED, from publicly available genome-wide association studies (GWASs). Subsequently, a 2-sample MR analysis was conducted using these datasets. The primary MR analysis utilized the inverse variance-weighted (IVW) method, complemented by secondary analyses employing MR-Egger and weighted median methods. Furthermore, we assessed heterogeneity using Cochran's Q test and evaluated pleiotropy with the MR-Egger intercept test. To identify potential influential single nucleotide polymorphisms, we employed a leave-one-out analysis. Additionally, outliers were identified using the MR-PRESSO method.

Outcomes

The study outcomes encompassed results from 3 MR analyses, namely IVW, MR-Egger, and weighted median, along with sensitivity analyses involving Cochran's Q test, the MR-Egger intercept test, leave-one-out analysis, and the MR-PRESSO method.

Results

There was no causal effect of UC and CD on ED in the MR analysis (IVW P > .05). Results of complementary methods were consistent with those of the IVW method. The results of sensitivity analyses supported our conclusion, and no directional pleiotropy was found.

Clinical Implications

Genetically, despite the absence of a causal link between IBD and ED according to MR analysis, we must emphasize the elevated ED prevalence among IBD patients in observational studies, with particular consideration for the influence of negative emotions on erectile function.

Strengths & Limitations

This study is the inaugural application of a 2-sample MR analysis using extensive GWAS datasets to evaluate the causal relationship between IBD and ED, effectively mitigating biases stemming from confounding factors and reverse causality often present in observational studies. Nevertheless, it is imperative to exercise caution when drawing conclusions due to inherent limitations in GWAS data, encompassing factors like samples overlap, gender categorization, population ancestry, and the persistent ambiguity surrounding the precise functionality of specific single nucleotide polymorphisms.

Conclusions

MR analysis did not provide genetic-level evidence supporting a direct causal relationship between IBD (UC and CD) and ED.

Lipid metabolism and neuromuscular junction as common pathways underlying the genetic basis of erectile dysfunction and obstructive sleep apnea

Erectile dysfunction (ED) incidence is higher in patients with obstructive sleep apnea (OSA). Studies have suggested that ED and OSA may activate similar pathways; however, few have investigated the links between their underlying genotypic profiles. Therefore, we conducted an in-silico analysis to test whether ED and OSA share genetic variants of risk and to identify any molecular, cellular and biological interactions between them. Two gene lists were manually curated through a literature review based on a PUBMED search, which resulted in one gene list associated with ED (total of 205 genes) and the other with OSA (total of 2622 genes). Between those gene sets, 35 were common for both lists (Fisher exact test, p-value = 0.027). The Protein-protein interaction (PPI) analysis using the intersect list as input showed that 3 of them had direct interactions (LPL, DGKB and PLCB1). In addition, the biological function of the genes contained in the intersect list suggested that pathways related to lipid metabolism and the neuromuscular junction were commonly found in the genetic basis of ED and OSA. From the shared genes between both conditions, the biological pathways highlighted in this study may serve as preliminary findings for future functional investigations on OSA and ED association.

Genetically predicted cardiovascular diseases could increase the risk of erectile dysfunction: a bidirectional Mendelian randomization

PURPOSE

Erectile dysfunction (ED) often appears concomitantly with cardiovascular diseases (CVDs). However, the causal relationship between ED and CVDs is still unclear. This study aimed to investigate the causal effects between CVDs and ED using bidirectional Mendelian randomization (MR).

METHODS

ED data (6175 cases and 217,630 controls) were obtained from the IEU OpenGWAS project. Seven types of CVDs were acquired in our study, including stroke (Sample size = 440,328), myocardial infection (Sample size = 184,305), coronary heart disease (Sample size = 86,995), hypertension (Sample size = 36,683), heart failure (Sample size = 208,178), atrial fibrillation (Sample size = 1,030,836), and coronary artery disease (Sample size = 141,217). Inverse variance weighted (IVW) was selected as the primary method for MR analysis.

RESULTS

IVW results indicated that stroke (OR = 1.14, 95% CI = 1.02-1.29, P = 0.025), coronary artery disease (OR = 1.09, 95% CI = 1.02-1.16, P = 0.013), coronary heart disease (OR = 1.07, 95% CI = 1.01-1.13, P = 0.017), myocardial infection (OR = 1.09, 95% CI = 1.02-1.17, P = 0.011), and atrial fibrillation (OR = 1.06, 95% CI = 1.00-1.12, P = 0.04) were causally associated with ED. The reverse MR analysis suggested that ED did not influence the prevalence of CVDs.

CONCLUSION

These findings highlighted CVDs as causal risk factors for ED, but ED did not directly result in the development of CVDs. Regular monitoring of the erectile function of individuals with CVDs, along with implementing appropriate preventive measures, might help reduce the incidence of ED and enhance the sexual well-being of patients with CVDs.

Causal effects of gut microbiota on erectile dysfunction: a two-sample Mendelian randomization study

Background

Several observational studies have reported the correlation between gut microbiota and the risk of erectile dysfunction (ED). However, the causal association between them remained unestablished owing to intrinsic limitations, confounding factors, and reverse causality. Therefore, the two-sample Mendelian randomization (MR) study was performed to determine the causal effect of gut microbiota on the risk of ED.

Methods

The MR analysis utilized the publicly available genome-wide association study (GWAS) summary-level data to explore the causal associations between gut microbiota and ED. The gut microbiota data were extracted from the MiBioGen study (N = 18,340), and the ED data were extracted from the IEU Open GWAS (6,175 ED cases and 217,630 controls). The single nucleotide polymorphisms (SNPs) served as instrumental variables (IVs) by two thresholds of P-values, the first P-value setting as <1e-05 (locus-wide significance level) and the second P-value setting as <5e-08 (genome-wide significance level). The inverse variance weighted approach was used as the primary approach for MR analysis, supplemented with the other methods. In addition, sensitivity analyses were performed to evaluate the robustness of the MR results, including Cochran's Q test for heterogeneity, the MR-Egger intercept test for horizontal pleiotropy, the Mendelian randomization pleiotropy residual sum, and outlier (MR-PRESSO) global test for outliers, and the forest test and leave-one-out test for strong influence SNPs.

Results

Our results presented that the increased abundance of Lachnospiraceae at family level (OR: 1.265, 95% CI: 1.054-1.519), Senegalimassilia (OR: 1.320, 95% CI: 1.064-1.638), Lachnospiraceae NC2004 group (OR: 1.197, 95% CI: 1.018-1.407), Tyzzerella3 (OR: 1.138, 95% CI: 1.017-1.273), and Oscillibacter (OR: 1.201, 95% CI: 1.035-1.393) at genus level may be risk factors for ED, while the increased abundance of Ruminococcaceae UCG013 (OR: 0.770, 95% CI: 0.615-0.965) at genus level may have a protective effect on ED. No heterogeneity or pleiotropy was found based on the previously described set of sensitivity analyses.

Conclusion

Our MR analysis demonstrated that the gut microbiota had inducing and protective effects on the risk of ED. The results provide clinicians with novel insights into the treatment and prevention of ED in the future. Furthermore, our study also displays novel insights into the pathogenesis of microbiota-mediated ED.

Causal association of cardiovascular disease with erectile dysfunction: a two-sample bidirectional Mendelian randomization analysis

BACKGROUND

The association between cardiovascular diseases (CVD), including ischemic stroke (IS), heart failure (HF), myocardial infarction (MI), and coronary heart disease (CHD), and erectile dysfunction (ED) remains unclear from observational studies.

OBJECTIVES

We explored the potential bidirectional association between CVD and ED by Mendelian randomization (MR).

METHODS

Data from genome-wide association studies for CVD in individuals with European ancestry were obtained from several databases, with 1,711,875-977,323 participants, while that for ED included 223,805 participants. We conducted univariate MR (UVMR), inverse variance-weighting (IVW), weighted median, MR-Egger, and multivariate MR (MVMR) analyses to explore the bidirectional causal effects between CVD and ED.

RESULTS

UVMR indicated that IS (odds ratios [OR] = 1.34, 95% confidence interval [CI]: 1.08-1.21, P = 0.007), HF (OR = 1.36, 95% CI 1.07-1.74, P = 0.013), and CHD (OR = 1.15, 95% CI 1.09-1.18, P = 0.022) were associated with ED. By MVMR, IS estimates remained significant after accounting for combining single nucleotide polymorphisms from CVDs (OR = 1.42, 95%CI: 1.13-1.79, P = 0.002). Moreover, the effect of a genetic susceptibility to IS on ED was not mediated by type 2 diabetes or triglycerides; that of HF was not mediated by type 2 diabetes, and that of CHD was not mediated by body mass index. Bidirectional analyses showed that genetic susceptibility to ED did not confer any increased CVD risk.

CONCLUSIONS

Our results, based on MR, indicated that genetic susceptibility to IS, HF, and CHD was causally associated with ED. These findings can inform prevention and intervention strategies for ED in IS, HF, and CHD patients.

Evaluation of bi-directional causal association between periodontal disease and erectile dysfunction: a two-sample Mendelian randomization study

BACKGROUND

The association between periodontal disease (PD) and erectile dysfunction (ED) has been well-documented in observational studies. However, observational studies are vulnerable to reverse causality and confounding factors, making the inference of causal-effect relationships challenging. Contrary to the current belief, Mendelian randomization (MR) can be applied to comprehensively assess the bi-directional causal effects between PD and ED.

METHODS

A two-sample MR analysis was performed using pooled statistics from genome-wide association studies involving European populations with PD (12,289 patients with PD and 22,326 controls) and ED (6,175 patients with clinically diagnosed ED and 217,630 controls). In this MR analysis, three methods--the inverse-variance weighted (IVW) average, weighted median, and MR-Egger regression methods--were used to evaluate the causal relationships between PD and ED.

RESULTS

According to the IVW analysis results, genetically predicted PD did not have a causal effect on ED (odds ratio 1.07, 95% confidence interval 0.96-1.20, p = 0.22). Furthermore, there was no clear indication of a significant causal effect of ED on PD in the reverse MR analysis (odds ratio 0.98, 95% confidence interval 0.90-1.08, p = 0.74). The results of the MR-Egger regression and weighted median methods were consistent with those of the IVW method. Based on the sensitivity analysis results, a major bias from genetic pleiotropy was unlikely to distort the causal estimates.

CONCLUSION

The present study does not support a causal effect between PD and ED.

CLINICAL RELEVANCE

From the perspective of genetics, PD does not appear to be a risk factor for the development of ED.

Association between genetically proxied HMGCR inhibition and male reproductive health: A Mendelian randomization study

BACKGROUND

The causal associations between statin use and male sex hormone levels and related disorders have not been fully understood. In this study, we employed Mendelian randomization for the first time to investigate these associations.

METHODS

In two-sample Mendelian randomization framework, genetic proxies for hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) inhibition were identified as variants in the HMGCR gene that were associated with both levels of gene expression and low density lipoprotein cholesterol (LDL-C). We assessed the causal relationship between HMGCR inhibitor and 5 sex hormone levels/2 male-related diseases. Additionally, we investigated the association between 4 circulating lipid traits and outcomes. The "inverse variance weighting" method was used as the primary approach, and we assessed for potential heterogeneity and pleiotropy. In a secondary analysis, we revalidated the impact of HMGCR on 7 major outcomes using the summary-data-based Mendelian randomization method.

RESULTS

Our study found a significant causal association between genetic proxies for HMGCR inhibitor and decreased levels of total testosterone (TT) (LDL-C per standard deviation = 38.7mg/dL, effect = -0.20, 95% confidence interval [CI] = -0.25 to -0.15) and bioavailable testosterone (BT) (effect = -0.15, 95% CI = -0.21 to -0.10). Obesity-related factors were found to mediate this association. Furthermore, the inhibitor were found to mediate a reduced risk of prostate cancer (odds ratio = 0.81, 95%CI = 0.7-0.93) by lowering bioavailable testosterone levels, without increasing the risk of erectile dysfunction (P = .17). On the other hand, there was a causal association between increased levels of LDL-C, total cholesterol, triglycerides (TG) and decreased levels of TT, sex hormone-binding globulin, and estradiol.

CONCLUSIONS

The use of HMGCR inhibitor will reduce testosterone levels and the risk of prostate cancer without the side effect of erectile dysfunction. LDL-C, total cholesterol, and TG levels were protective factors for TT, sex hormone-binding globulin, and estradiol.

Mendelian randomization study reveals the effect of idiopathic pulmonary fibrosis on the risk of erectile dysfunction

Background

Several studies have found that erectile dysfunction (ED) is associated with interstitial lung disease. However, the causal relationship between idiopathic pulmonary fibrosis (IPF) and ED risk remains unclear. The present two-sample Mendelian randomization (MR) study aimed to reveal the causal effect of IPF on ED risk.

Methods

This study included two GWAS summary statistics of IPF (1,028 cases and 196,986 controls) and ED (6,175 cases and 217,630 controls) of European ancestry. The inverse-variance weighted (IVW) was applied as the primary method, and MR-Egger, weighted median, weighted mode, and simple mode were applied as complementary methods to estimate the causal impact of IPF on ED risk. The MR-PRESSO global test and MR-Egger regression were applied to evaluate the pleiotropy. The Cochran's Q test was applied to examine heterogeneity. The leave-one-out analysis ensured the robustness and reliability of the results.

Results

Twenty-one genetic variants were obtained as IPF instrumental variables without pleiotropy and heterogeneity. MR analysis using the IVW showed a potential causal relationship between IPF and increased ED risk (OR_IVW = 1.046, 95% CI: 1.020-1.073, p = 0.001), and consistent results were obtained with MR-Egger, weighted median, and weighted mode. The leave-one-out analysis showed that no instrumental variables unduly influenced the results.

Conclusion

This study suggested that IPF may increase the ED risk of the European population.

Causal association between JAK2 and erectile dysfunction: a Mendelian randomization study

BACKGROUND

As one of the most critical proteins in the JAK/STAT signaling pathway, Janus kinase 2 (JAK2) is involved in many biological processes and diseases. Several observational studies have reported the role of JAK2 in erectile dysfunction. However, the causal relationship between JAK2 and erectile dysfunction remains unclear. Here we investigated the causal relationship between JAK2 and erectile dysfunction.

RESULTS

Genetically predicted JAK2 was causally associated with erectile dysfunction in inverse variance weighting (OR = 1.109, 95% CI = 1.029-1.196, p = 0.007) and weighted median method (OR = 1.117, 95% CI = 1.003-1.245, p = 0.044). No heterogeneity was observed in Cochran Q-test (p = 0.855) and MR-PRESSO (p = 0.866). Pleiotropy was not observed in our study (p = 0.617).

CONCLUSIONS

These findings highlighted JAK2 as a risk factor for erectile dysfunction and proved the causal relationship between JAK2 and erectile dysfunction, suggesting that targeting JAK2 signaling might be a novel and promising therapeutic candidate in the treatment of erectile dysfunction.

Molecular Mechanisms and Risk Factors Related to the Pathogenesis of Peyronie's Disease

Peyronie's disease (PD) is a benign condition caused by plaque formation on the tunica albuginea of the penis. It is associated with penile pain, curvature, and shortening, and contributes to erectile dysfunction, which worsens patient quality of life. In recent years, research into understanding of the detailed mechanisms and risk factors involved in the development of PD has been increasing. In this review, the pathological mechanisms and several closely related signaling pathways, including TGF-β, WNT/β-catenin, Hedgehog, YAP/TAZ, MAPK, ROCK, and PI3K/AKT, are described. Findings regarding cross-talk among these pathways are then discussed to elucidate the complicated cascade behind tunica albuginea fibrosis. Finally, various risk factors including the genes involved in the development of PD are presented and their association with the disease summarized. The purpose of this review is to provide a better understanding regarding the involvement of risk factors in the molecular mechanisms associated with PD pathogenesis, as well as to provide insight into disease prevention and novel therapeutic interventions.

Genetically predicted hypertension, antihypertensive drugs, and risk of erectile dysfunction: a Mendelian randomization study

Background

The causal relationship between hypertension, antihypertensive drugs and the risk of erectile dysfunction is still uncertain. We performed a univariable and multivariable Mendelian randomization study to investigate whether they are causally related to erectile dysfunction.

Methods

Genetic variants associated with blood pressure were derived from the genome-wide association study meta-analysis of the UK Biobank and International Consortium of Blood Pressure (N = 757,601). Summary association data for hypertension were obtained from the UK Biobank (N = 463,010) and the FinnGen study (N = 356,077). The summary statistics of erectile dysfunction were obtained from the European ancestry with 223,805 subjects. The SNP instruments used to assess the effect of the protein targets of antihypertensive drugs on erectile dysfunction were obtained from previous studys. Causal effects were estimated using the univariate Mendelian randomization method (inverse variance weighted, MR-Egger, weighted median, MR-PRESSO and Wald ratios) and the multivariate Mendelian randomization method. Sensitivity analyses were implemented with the Cochran's Q-test, MR-Egger intercept test, MR-PRESSO, and leave-one-out analysis.

Results

Univariate MR found that elevated diastolic blood pressure may increase the occurrence of erectile dysfunction (odds ratio [OR] = 1.012; 95% confidence interval [CI]: 1.000-1.024; P = 0.047). Genetically predicted hypertension is also associated with ED (For the FinnGen, OR = 1.106; 95% CI: 1.027-1.191; P = 0.008. For the UK Biobank, OR = 3.832; 95% CI: 1.410-10.414; P = 0.008). However, after adjusting for systolic blood pressure, diastolic blood pressure and hypertension using multivariate Mendelian randomization, only hypertension was causally associated with ED occurrence (For the FinnGen, OR = 1.103; 95% CI: 1.018-1.195; P = 0.017. For the UK Biobank, OR = 5.037; 95% CI: 1.601-15.846; P = 0.006). We found no evidence that the use of angiotensin-converting enzyme inhibitors, beta-blockers, calcium channel blockers, and thiazide diuretic increased the risk of erectile dysfunction.

Conclusions

Genetically predicted hypertension increases the risk of erectile dysfunction, but we found no causal relationship between elevated systolic/diastolic blood pressure and erectile dysfunction. We speculate that the relationship between elevated blood pressure and erectile dysfunction risk may be nonlinear. We found little evidence that antihypertensive drugs increase the risk of erectile dysfunction.

Effects of major depression and bipolar disorder on erectile dysfunction: a two-sample mendelian randomization study

BACKGROUND AND AIMS

There are currently no clear conclusions about whether major depression (MD) and bipolar disorder (BD) increase the risk of erectile dysfunction (ED). In our study, we used a Mendelian randomization (MR) analysis to discover the causal associations between MD, BD and ED.

METHODS

We got single-nucleotide polymorphisms (SNPs) related to MD, BD and ED from the MRC IEU Open genome-wide association study (GWAS) datasets. After a series of selection, SNPs left were selected as instrumental variables (IVs) of MD and BD for the following MR test to evaluate the relationship of genetically predicted MD or BD with the incidence of ED. Among them, we used the random-effects inverse-variance weighted (IVW) method as the main analysis. Finally, sensitivity analyses were further performed using Cochran's Q test, funnel plots, MR-Egger regression, Leave-one-out method and MR- pleiotropy residual sum and outlier (PRESSO).

RESULTS

Genetically-predicted MD was causally related to the incidence of ED in the IVW methods (odds ratio (OR), 1.53; 95% confidence interval (CI), 1.19-1.96; p = 0.001), while no causal impact of BD on the risk of ED (OR = 0.95, 95% CI 0.87-1.04; p = 0.306). The results of sensitivity analyses supported our conclusion, and no directional pleiotropy were found.

CONCLUSION

The findings of this research found evidence of a causal relationship between MD and ED. However, we did not find a causal relationship between BD and ED in European populations.

Causal association between cardiovascular diseases and erectile dysfunction, a Mendelian randomization study

Background

Cardiovascular diseases (CVD), including coronary heart disease (CHD), heart failure, ischemic heart disease (IHD), and atrial fibrillation, are prevalent in the aged. However, the influence of CVD on ED is less investigated. This study was performed to clarify the causal association between CVD and ED.

Materials and methods

Genome-wide association studies (GWAS) datasets targeting CHD, heart failure, IHD, and atrial fibrillation were downloaded to retrieve single nucleotide polymorphisms (SNPs). Further, single-variable Mendelian randomization and multivariable Mendelian randomization (MVMR) were adopted to explore the causal association between CVD and ED.

Results

Genetically predicted CHD and heart failure were found to increase the risks of ED (OR = 1.09, P < 0.05 and OR = 1.36, P < 0.05, respectively). However, no causal association was disclosed among IHD, atrial fibrillation and ED (all P > 0.05). These findings remained consistent in sensitivity analyses. After controlling for body mass index, alcohol, low density lipoprotein, smoking and total cholesterol levels, the results of MVMR support the causal role of CHD on ED (P < 0.05). Similarly, the direct causal effect estimates of heart failure on ED were significant in MVMR analyses (P < 0.05).

Conclusion

Using genetic data, this study revealed that genetically predicted CHD and heart failure may predict better ED compared with atrial fibrillation and IHD. The results should be interpreted with caution and the insignificant causal inference of IHD still needs further verification in future studies.

A Guide for Selection of Genetic Instruments in Mendelian Randomization Studies of Type 2 Diabetes and HbA1c: Toward an Integrated Approach

In this study we examine the instrument selection strategies currently used throughout the type 2 diabetes and HbA1c Mendelian randomization (MR) literature. We then argue for a more integrated and thorough approach, providing a framework to do this in the context of HbA1c and diabetes. We conducted a literature search for MR studies that have instrumented diabetes and/or HbA1c. We also used data from the UK Biobank (UKB) (N = 349,326) to calculate instrument strength metrics that are key in MR studies (the F statistic for average strength and R2 for total strength) with two different methods ("individual-level data regression" and Cragg-Donald formula). We used a 157-single nucleotide polymorphism (SNP) instrument for diabetes and a 51-SNP instrument (with partition into glycemic and erythrocytic as well) for HbA1c. Our literature search yielded 48 studies for diabetes and 22 for HbA1c. Our UKB empirical examples showed that irrespective of the method used to calculate metrics of strength and whether the instrument was the main one or included partition by function, the HbA1c genetic instrument is strong in terms of both average and total strength. For diabetes, a 157-SNP instrument was shown to have good average strength and total strength, but these were both substantially lesser than those of the HbA1c instrument. We provide a careful set of five recommendations to researchers who wish to genetically instrument type 2 diabetes and/or HbA1c. In MR studies of glycemia, investigators should take a more integrated approach when selecting genetic instruments, and we give specific guidance on how to do this.

Causal effects of hypertension on risk of erectile dysfunction: A two-sample Mendelian randomization study

Background

Erection dysfunction has been associated with hypertension in several epidemiological and observational studies. But the causal association between hypertension and erectile dysfunction requires further investigation.

Methods

A two-sample Mendelian randomization (MR) was conducted to analyze the causal effect of hypertension on risk of erection dysfunction. Large-scale publicly available genome-wide association study data were used to estimate the putative causality between hypertension and risk of erectile dysfunction. A total of 67 independent single nucleotide polymorphisms were selected as instrumental variables. Inverse-variant weighted, maximum likelihood, weighted median, penalized weighted median, and MR-PRESSO approaches were utilized in MR analyses. Heterogeneity test, horizontal pleiotropy test, and leave-one-out method were used to prove the stability of the results.

Results

In total, all P values were less than 0.05, demonstrating a positive causal link between hypertension and risk of erectile dysfunction in multiple MR methods, such as inverse-variant weighted (random and fixed effect) (OR 3.8315, 95% CI 2.3004-6.3817, P = 0.0085), maximum likelihood (OR 3.8877, 95% CI 2.3224-6.5081, P = 0.0085), weighted median (OR 4.9720, 95% CI 2.3645-10.4550, P = 0.0309), penalized weighted median (OR 4.9760, 95% CI 2.3201-10.6721, P = 0.0355), and MR-PRESSO (OR 3.6185, 95% CI 2.2387-5.8488, P = 0.0092). Sensitivity analysis detected no evidence of heterogeneity, pleiotropy, or outlier single nucleotide polymorphisms.

Conclusion

The study revealed a positive causal link between the presence of hypertension and the risk of erectile dysfunction. More attention should be paid during the management of hypertension with the purpose of preventing erectile dysfunction or improving erectile function.

Erectile Dysfunction: Causes, Diagnosis and Treatment: An Update

Erectile Dysfunction (ED) is defined as "recurrent and persistent inability, partial or complete, to achieve or maintain an erection firm enough for satisfactory sexual intercourse in the presence of proper erotic stimuli"; the concept of ED replaced the previous definition of "impotence" [...].

Genetic evidence suggests that depression increases the risk of erectile dysfunction: A Mendelian randomization study

Background: The causal relationship between depression and erectile dysfunction (ED) is still uncertain.

Objectives: To identify the genetically predicted causality of depression on ED through Mendelian randomization (MR).

Materials and methods: A comprehensive GWAS meta-analysis comprising 807,553 Europeans provided single-nucleotide polymorphism (SNP) information for depression, and another genome-wide association analysis involving 223,805 European ancestries measured SNPs for ED. The inverse variance weighted (IVW) method was used as the primary MR analysis method to evaluate causal effects. In addition, the maximum likelihood method, MR-Egger, weighted median, robust adjusted contour score (MR.RAPS), and MR pleiotropic residual and outlier (MR-PRESSO) methods were used as supplements for sensitivity analysis.

Results: According to the IVW analysis, depression significantly increases the incidence of ED (odds ratio [OR] = 1.68, 95% confidence interval [CI] = 1.38–2.05, p < 0.001). In sensitivity analyses, the ORs for the maximum likelihood method, MR-Egger, weighted median, MR.RAPS, and MR-PRESSO are 1.70 (95% CI = 1.39–2.08, p < 0 .001), 1.94 (95% CI = 0.63–6.01, p > 0 .05), 1.59 (95% CI = 1.21–2.10, p < 0 .001), 1 .70 (95% CI = 1.39–2.08, p < 0 .001), and 1.68 (95% CI = 1.40–2.04, p < 0 .001). There is no clear indication of potential heterogeneity or pleiotropy (p for the MR-Egger intercept = 0.804; p for the global test = 0.594; and p for Cochran’s Q statistics >0.05).

Conclusion: Genetically predicted depression plays a potentially causal role in the occurrence of ED.

Associations between depression and cardiometabolic health: A 27-year longitudinal study

BACKGROUND

Clarifying the relationship between depression symptoms and cardiometabolic and related health could clarify risk factors and treatment targets. The objective of this study was to assess whether depression symptoms in midlife are associated with the subsequent onset of cardiometabolic health problems.

METHODS

The study sample comprised 787 male twin veterans with polygenic risk score data who participated in the Harvard Twin Study of Substance Abuse ('baseline') and the longitudinal Vietnam Era Twin Study of Aging ('follow-up'). Depression symptoms were assessed at baseline [mean age 41.42 years (s.d. = 2.34)] using the Diagnostic Interview Schedule, Version III, Revised. The onset of eight cardiometabolic conditions (atrial fibrillation, diabetes, erectile dysfunction, hypercholesterolemia, hypertension, myocardial infarction, sleep apnea, and stroke) was assessed via self-reported doctor diagnosis at follow-up [mean age 67.59 years (s.d. = 2.41)].

RESULTS

Total depression symptoms were longitudinally associated with incident diabetes (OR 1.29, 95% CI 1.07-1.57), erectile dysfunction (OR 1.32, 95% CI 1.10-1.59), hypercholesterolemia (OR 1.26, 95% CI 1.04-1.53), and sleep apnea (OR 1.40, 95% CI 1.13-1.74) over 27 years after controlling for age, alcohol consumption, smoking, body mass index, C-reactive protein, and polygenic risk for specific health conditions. In sensitivity analyses that excluded somatic depression symptoms, only the association with sleep apnea remained significant (OR 1.32, 95% CI 1.09-1.60).

CONCLUSIONS

A history of depression symptoms by early midlife is associated with an elevated risk for subsequent development of several self-reported health conditions. When isolated, non-somatic depression symptoms are associated with incident self-reported sleep apnea. Depression symptom history may be a predictor or marker of cardiometabolic risk over decades.

Genetic susceptibility to COVID-19 may increase the risk of erectile dysfunction: A two-sample Mendelian randomization study

Coronavirus disease 19 (COVID‐19) and erectile dysfunction (ED) have been linked in some observational research, but the causality of this association in the European population is uncertain. Therefore, the research intended to investigate the causality of susceptibility to COVID‐19 on ED. We used Mendelian randomization (MR) analysis for this research. The subjects were from two genome‐wide association studies (GWAS) of the European population, including COVID‐19 (14,134 cases and 1,284,876 controls) and ED (6175 cases and 217,630 controls). We utilized the inverse variance‐weighted (IVW) to evaluate the causality of COVID‐19 genetic susceptibility on ED. Heterogeneity and pleiotropy were determined using the Cochran's Q test and MR‐Egger regression. The robustness of the findings was verified using the Leave‐one‐out method. We obtained six single nucleotide polymorphisms (SNPs) as COVID‐19 genetic instrumental variables (IVs), and there was no significant pleiotropy, heterogeneity or bias in these IVs. MR analysis revealed the causality of genetic susceptibility to COVID‐19 on elevated risk of ED (OR_IVW = 1.235, 95% CI: 1.044–1.462, p < 0.05). The present study suggested the causality of genetic susceptibility to COVID‐19 on elevated ED risk among the European population. Therefore, in order to decrease the ED risk, the European population ought to positively prevent COVID‐19.

Genetic Evidence Supporting a Causal Role of Snoring in Erectile Dysfunction

Background

The association between snoring and erectile dysfunction (ED) is inconsistent in multiple observational studies. To clarify the causal association of snoring on ED, we performed this two-sample Mendelian randomization study.

Materials and Methods

The single nucleotide polymorphisms (SNPs) associated with snoring were retrieved from the UK biobank cohort with 314,449 participants (117,812 cases and 196,637 controls). The summary statistics of ED were obtained from the European ancestry with 223,805 subjects (6,175 cases and 217,630 controls). Single-variable Mendelian randomization (MR) and multivariable MR were used to assess the causal relationship between snoring and ED.

Results

Snoring increases the risk of ED (Odds ratio [OR] = 3.45, 95% confidence interval [CI] = 1.68 - 7.09, P < 0.001) in the inverse variance weighting estimator. In sensitivity analyses, the ORs for the weighted median, MR robust adjusted profile score, and MR Pleiotropy Residual Sum and Outlier approach, MR-Egger, and maximum likelihood method are 5.70 (95% CI = 1.19 - 27.21, P < 0.05), 3.14 (95% CI = 1.01 - 9.72, P < 0.05), 3.11 (95% CI = 1.63 - 5.91, P < 0.01), 1.23 (95% CI = 0.01 - 679.73, P > 0.05), and 3.59 (95% CI = 1.07 - 12.00, P < 0.05), respectively. No heterogeneity and pleiotropy are observed (P for MR-Egger intercept = 0.748; P for global test = 0.997; P for Cochran's Q statistics > 0.05). After adjusting for total cholesterol, triglyceride, low-density lipoprotein, and cigarette consumption, the ORs for ED are 5.75 (95% CI = 1.80 - 18.34, P < 0.01), 4.16 (95% CI = 1.10 - 15.81, P < 0.05), 5.50 (95% CI = 1.62 - 18.69, P < 0.01), and 2.74 (95% CI = 1.06 - 7.10, P < 0.05), respectively.

Conclusion

This study provides genetic evidence supporting the causal role of snoring in ED.

Type 2 diabetes mellitus increases risk of erectile dysfunction independent of obesity and dyslipidemia: A Mendelian randomization study

BACKGROUND

The causal effects of individual risk factors of metabolic syndrome on erectile dysfunction (ED) are still unclear.

OBJECTIVES

To evaluate the causal effect of risk factors of metabolic syndrome on ED through Mendelian randomization (MR).

MATERIALS AND METHODS

Data for risk factors were obtained from multiple databases with 173,082-757,601 individuals, and that for ED were collected from a genome-wide association study including 223,805 Europeans. We performed univariate MR analysis using inverse-variance weighted, MR-Egger, weighted-median, weighted mode methods and multivariable MR analysis to evaluate the total and direct causal effects.

RESULTS

The univariable MR supported that type 2 diabetes mellitus (odds ratios [OR] = 1.14, 95% confidence intervals [CI]: 1.08-1.21, p < 0.001) and body mass index (BMI) (OR = 1.27, 95% CI: 1.12-1.44, p < 0.001) were associated with ED. After excluding the SNPs associated with BMI and other risk factors, the results of multivariable MR for T2D (OR = 1.15, 95% CI: 1.05-1.25, p = 0.001) remained consistent. However, the results of multivariable MR provided limited evidence for the causality between BMI and ED (OR = 1.06, 95% CI: 0.88-1.29, p = 0.532). For systolic blood pressure and lipid components (low-density lipoprotein, high-density lipoprotein and triglycerides), both univariable and multivariable MR failed to offer sufficient evidence to confirm their causal effect on ED.

CONCLUSION

T2D showed a direct causal effect on ED independent of obesity and dyslipidemia.

Causal Associations Between Educational Attainment and 14 Urological and Reproductive Health Outcomes: A Mendelian Randomization Study

Background: The impact of educational attainment (EA) on multiple urological and reproductive health outcomes has been explored in observational studies. Here we used Mendelian randomization (MR) to investigate whether EA has causal effects on 14 urological and reproductive health outcomes.

Methods: We obtained summary statistics for EA and 14 urological and reproductive health outcomes from genome-wide association studies (GWAS). MR analyses were applied to explore the potential causal association between EA and them. Inverse variance weighted was the primary analytical method.

Results: Genetically predicted one standard deviation (SD) increase in EA was causally associated with a higher risk of prostate cancer [odds ratio (OR) 1.14, 95% confidence interval (CI) 1.05–1.25, P = 0.003] and a reduced risk of kidney stone (OR 0.73, 95% CI 0.62–0.87, P < 0.001) and cystitis (OR 0.76, 95% CI 0.67–0.86, P < 0.001) after Bonferroni correction. EA was also suggestively correlated with a lower risk of prostatitis (OR 0.76, 95% CI 0.59–0.98, P = 0.037) and incontinence (OR 0.64, 95% CI 0.47–0.87, P = 0.004). For the bioavailable testosterone levels and infertility, sex-specific associations were observed, with genetically determined increased EA being related to higher levels of testosterone in men (β 0.07, 95% CI 0.04–0.10, P < 0.001), lower levels of testosterone in women (β −0.13, 95% CI−0.16 to−0.11, P < 0.001), and a lower risk of infertility in women (OR 0.74, 95% CI 0.64–0.86, P < 0.001) but was not related to male infertility (OR 0.79, 95% CI 0.52–1.20, P = 0.269) after Bonferroni correction. For bladder cancer, kidney cancer, testicular cancer, benign prostatic hyperplasia, and erectile dysfunction, no causal effects were observed.

Conclusions: EA plays a vital role in urological diseases, especially in non-oncological outcomes and reproductive health. These findings should be verified in further studies when GWAS data are sufficient.

Quercetin enhances sexual behavior and improves ectonucleotidases activity in the hypothalamus of rats treated with cyclosporine

In order to confirm the erectile potential of Quercetin (Q) in cyclosporine-induced hypertensive rats, this research assesses the influence of Q on the ectonucleotidases and adenosine deaminase (ADA) in the brains of rats. Male Wistar rats (200 g-250 g) were divided into five groups at random: Normal control (CTRL), cyclosporine-induced hypertensive rats (25 mg kg day-1 ) (HT) group, positive control (Sildenafil [SIL], 5 mg kg day-1 ), Quercetin 25 mg kg day-1 (25 Q), and Quercetin 50 mg kg day-1 (50 Q). Aside from standard diet-fed male rats; cyclosporine was given i.p for the period of 30 days as well as Q orally while the female rats were only given a standard diet. The animals were subjected to sexual activity (copulation) after which the male rat hypothalamus was dissected for biochemical examination (E-NTPDase activities, ecto-5'-nucleotidase as well as ADA and also levels of nitric oxide [NO]). We observed that Q enhanced copulatory behavior as evident in mounting, intromission, ejaculation numbers, and latencies. A substantial (p < .05) increase in the activity of E-NTPDase (ATP and ADP as substrate) without any notable difference in the action of ecto-5' nucleotidase was facilitated by cyclosporine-induction when compared to the CTRL. The 50 mg/kg, however, had the highest reversal effect in accordance with dose manner. Also, cyclosporine increased ADA activity with a concomitant reduction of NO level while both doses of Q down-regulated ADA activity and, increased NO levels. Enhanced sexual behavior, modulation of ectonucleotidases as well as ADA activity and increased NO levels suggest that Q-rich plant foods may be promising sources of dietary phytonutrients for erectile dysfunction (ED) management. PRACTICAL APPLICATIONS: Behavioral and biochemical assays evaluated showed that Q significantly enhanced sexual behavior as well as improved ATP bioavailability in cyclosporine-induced erectile dysfunctional rats. The modulatory effects of Q on ectonucleotidases, along with its ability to minimize adenosine deaminase activity and increase nitric oxide levels, indicate that Q-rich plants and/or plant foods may be promising sources of dietary phytonutrients for erectile dysfunction management.

A genome-wide association study to identify candidate genes for erectile dysfunction

Erectile dysfunction (ED) can be caused by different diseases and controlled by several genetic networks. In this study, to identify the genes related to ED, the expression profiles of normal and ED samples were investigated by the Gene Expression Omnibus (GEO) database. Seventeen genes were identified as associated genes with ED. The protein and nucleic acid sequences of selected genes were retrieved from the UCSC database. Selected genes were diverse according to their physicochemical properties and functions. Category function revealed that selected genes are involved in pathways related to humans some diseases. Furthermore, based on protein interactions, genes associated with the insulin pathway had the greatest interaction with the studied genes. To identify the common cis-regulatory elements, the promoter site of the selected genes was retrieved from the UCSC database. The Gapped Local Alignment of Motifs tool was used for finding common conserved motifs into the promoter site of selected genes. Besides, INSR protein as an insulin receptor precursor showed a high potential site for posttranslation modifications, including phosphorylation and N-glycosylation. Also, in this study, two Guanine-Cytosine (GC)-rich regions were identified as conserved motifs in the upstream of studied genes which can be involved in regulating the expression of genes associated with ED. Also, the conserved binding site of miR-29-3p that is involved in various cancers was observed in the 3' untranslated region of genes associated with ED. Our study introduced new genes associated with ED, which can be good candidates for further analyzing related to human ED.

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.

A genome-wide association study identifies FSHR rs2300441 associated with follicle-stimulating hormone levels

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) play critical roles in female reproduction, while the underlying genetic basis is poorly understood. Genome-wide association studies (GWASs) of FSH and LH levels were conducted in 2590 Chinese females including 1882 polycystic ovary syndrome (PCOS) cases and 708 controls. GWAS for FSH level identified multiple variants at FSHR showing genome-wide significance with the top variant (rs2300441) located in the intron of FSHR. The A allele of rs2300441 led to a reduced level of FSH in the PCOS group (β = -.43, P = 6.70 × 10^-14 ) as well as in the control group (β = -.35, P = 6.52 × 10^-4 ). In the combined sample, this association was enhanced after adjusting for the PCOS status (before: β = -.38, P = 1.77 × 10^-13 ; after: β = -.42, P = 3.33 × 10^-16 ), suggesting the genetic effect is independent of the PCOS status. The rs2300441 explained sevenfold higher proportion of the FSH variance than the total variance explained by the two previously reported FSHR missense variants (rs2300441 R² = 1.40% vs rs6166 R² = 0.17%, rs6165 R² = 0.03%). GWAS for LH did not identify any genome-wide significant associations. In conclusion, we identified genome-wide significant association between variants in FSHR and circulating FSH first, with the top associated variant rs2300441 might be a primary contributor at the population level.

Next-generation drug repurposing using human genetics and network biology

Drug repurposing has attracted increased attention, especially in the context of drug discovery rates that remain too low despite a recent wave of approvals for biological therapeutics (e.g. gene therapy). These new biological entities-based treatments have high costs that are difficult to justify for small markets that include rare diseases. Drug repurposing, involving the identification of single or combinations of existing drugs based on human genetics data and network biology approaches represents a next-generation approach that has the potential to increase the speed of drug discovery at a lower cost. This Pharmacological Perspective reviews progress and perspectives in combining human genetics, especially genome-wide association studies, with network biology to drive drug repurposing for rare and common diseases with monogenic or polygenic etiologies. Also, highlighted here are important features of this next generation approach to drug repurposing, which can be combined with machine learning methods to meet the challenges of personalized medicine.

The association of Intron 4 VNTR and Glu298Asp polymorphisms of the nitric oxide synthetase 3 gene and vasculogenic erectile dysfunction in Turkish men

Several studies have focused on the impaired role of endothelial nitric oxide synthase (NOS3) gene polymorphism and its association to erectile dysfunction (ED). However, currently controversial results have been reported due to their significant heterogeneity. The present study aimed to assess the genotypic distribution and the allelic frequency of Intron 4 VNTR and Glu298Asp gene polymorphisms in vasculogenic ED patients compared to healthy controls of a specific region of Turkey. A total of 75 patients with ED (median age: 56, IQR:10.5) and 75 healthy controls (median age: 56, IQR:10.5) were prospectively analyzed. All subjects were equally evaluated by the same physician with detailed history-taking, physical examination, International Index of Erectile Function (IIEF) questionnaire, and blood tests (incl. glucose, testosterone, triglyceride and total cholesterol level). Those with an IIEF score under 26 were considered to have ED, by classifying them according to their scores as mild (22-25), moderate (11-21) and severe (1-10) ED. Color doppler ultrasonography was carried out in patients with an IIEF score <22. Hypertension, diabetes mellitus, coronary artery disease, and smoking status were significantly associated with the ED group compared to control subjects with p values of <0.001, <0.001, 0.002 and <0.001, respectively. Overall genotype frequencies was 47 (31%) a/a, 22 (15%) a/b, 82 (55%) b/b for Intron 4 VNTR and 56 (37%) GG, 78 (52%) GT, 16 (11%) TT for the Glu298Asp polymorphism. The frequencies of Intron 4 VNTR a/a allele and Glu298Asp GT allele were associated with severe ED, while a/b and TT were associated with moderate or mild, and b/b and GG were associated with no ED. In contrast to Glu298Asp, statistically significant differences in genotypic frequencies of Intron 4 VNTR gene polymorphism between ED and control subjects was established. Abbreviations: NO: nitric oxide, NOS: nitric oxide synthase, NOS3: endothelial nitric oxide synthase, NOS2: inducible nitric oxide synthase, NOS1: neuronal nitric oxide synthase, HT: hypertension, DM: diabetes mellitus, CAD: coronary artery disease, ED: erectile dysfunction, IIEF: international index of erectile function, VNTR: variable number of tandem repeats, CDU: color doppler ultrasonography, PCR: polymerase chain reaction.