Novel predictive risk factor for Erectile Dysfunction: Serum folic acid

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.

Serum folic acid: an effective indicator for arteriogenic erectile dysfunction

Background

The present study is the first to explore the correlation between serum folic acid (FA) level and penile arterial peak systolic velocity (PSV) as measured via penile color Doppler ultrasonography (PDU), which directly reflects endothelial function in the penile artery.

Materials and methods

A total of 244 consecutive erectile dysfunction (ED) patients and 72 healthy controls, recruited from the Andrology department and the Healthy Physical Examination Center of our hospital, respectively, from June 2020 to April 2022, were included in the study. Serum FA was measured in ED patients and healthy controls, and PDU examinations were conducted for all eligible ED patients. The Pearson method was used to evaluate the correlation between FA levels and PDU parameters in ED patients. A receiver operating characteristic (ROC) curve analysis was also performed to calculate the sensitivity and specificity of these parameters for prediction of arteriogenic ED.

Results

After the PDU test, the average serum FA level among patients diagnosed with arteriogenic ED was 8.08 ± 2.64 ng/ml, lower than the average of 10.78 ± 2.87 ng/ml among healthy controls. There were no statistically significant inter-group differences on any basic parameters, including age, body mass index, fasting blood glucose, total cholesterol, and triglyceride. For further analysis, we divided the arteriogenic ED group into three subgroups by PSV range to compare serum FA levels among these subgroups. The mean FA levels in each of these groups were 5.97 ± 1.51ng/ml, and 8.21 ± 2.37ng/ml, and 10.55 ± 2.56ng/ml, while the corresponding PSV values were 15.75 ± 2.39cm/s, 23.53 ± 2.19cm/s, and 32.72 ± 1.64cm/s. Overall, a positive correlation between PSV and FA level was found among patients with arteriogenic ED (r=0.605, P<0.001). Furthermore, when FA level was used, with a cut-off value of 10.045 ng/ml, as a criterion to distinguish patients with arteriogenic ED from healthy controls, the area under the curve (AUC) was 0.772 (95% confidential interval: [0.696, 0.848]), for a sensitivity of 0.611 and specificity of 0.824.

Conclusion

Serum FA level is positively correlated with PSV in ED patients, and has the ability to distinguish patients with arteriogenic ED from healthy controls. Taking these findings together, FA deficiency should be regarded as an independent risk factor for arteriogenic ED.

Serum Folic Acid and Erectile Dysfunction: A Systematic Review and Meta-Analysis

Introduction

The association between folic acid (FA) and erectile dysfunction (ED) was contradictory in the published original articles, and no meta-analysis was conducted to pool these data.

Aim

To verify the role of FA in the pathology of ED and explore the treatment efficacy of FA for ED patients.

Methods

An extensive search was performed on PubMed, Cochrane Library, and Web of Science to obtain all relevant studies published up to October 31, 2020. Studies comparing the serum FA level between ED patients and healthy controls, or comparing the score of the IIEF-5, or IIEF before and after folic acid therapy alone or combination in ED patient were eligible for our meta-analysis. The Newcastle-Ottawa Scales (NOS) was used to qualify included studies.

Main Outcome Measures

The standardized mean differences (SMD) and their corresponding 95% confidence intervals (95% CIs) were calculated to pool our data.

Results

Nine studies were eligible for our meta-analysis to verify the association between FA and ED, and to explore the treatment efficacy of FA for ED patients. The pooled SMD of the FA level difference between ED patients and healthy subjects was -0.94 (95% CI: -1.59, -0.30, P = .004). Moreover, the level of folic acid in healthy subjects, Mild ED patients, Moderate ED patients and Severe ED patients was 11.847 (95%CI = 9.671, 14.022), 9.496 (95%CI = 8.425, 10.567), 6.597 (95%CI = 5.187, 8.007) and 5.623 (95%CI = 3.535, 7.711) respectively. The SMD of changes in score of IIEF-5 was 1.89 with 95%CI (1.60, 2.17) after FA administration in ED patients. Our analysis also showed that combination therapy of FA plus tadalafil changed the score of IIEF with 0.90 (95%CI = 0.44, 1.36) comparing to combination of placebo plus tadalafil.

Conclusion

This novel meta-analysis demonstrated that FA was an independent risk factor for ED and FA supplement may have potentially positive effects in the treatment of ED patients.

Zhang Y, Zhang W, Dai Y, et al. Serum Folic Acid and Erectile Dysfunction: A Systematic Review and Meta-Analysis. Sex Med 2021;9:100356.

Serum folic acid levels and erectile dysfunction: A meta-analysis and systematic review

The aim of this study was to assess the relationship between serum folic acid (FA) levels and erectile dysfunction (ED) through a meta-analysis. A research was conducted in MEDLINE via PubMed, Cochrane Library, EMBASE and Web of Science up to 22 November 2020 to identify studies related to FA and ED. Two authors independently screened the literature, evaluated methodological quality and extracted the data. We used RevMan5.3 and STATA 14.0 for meta-analysis. A total of six studies including 1,842 participants were included, and the results showed that the FA levels in the non-ED group were significantly higher than those in the ED group (MD = 3.37, 95% CI 1.49-5.52, p = 0.004). Subgroup analysis indicated that with the increase in ED severity, the difference in FA levels between groups was more obvious (MD: 1.99 vs. 4.63 vs. 5.63). The differences in FA levels between groups seem more significant in the younger group (MD = 4.87, 95% CI 2.58-6.89, p < 0.001) than in the older group (MD = 3.15, 95% CI 2.21-4.08, p < 0.001). In conclusion, FA deficiency is closely related to ED, and the degree of FA deficiency may reflect the severity of ED. In addition, the association seems to be more pronounced in the younger group.