Is lower low-density lipoprotein cholesterol associated with lower androgen and erectile dysfunction in men?

Non-linear association between testosterone and LDL concentrations in men

BACKGROUND

Contradictory data have been reported about the association between testosterone levels and the levels of low-density lipoprotein cholesterol (LDL).

OBJECTIVES

The aim of this study was to elucidate the association between testosterone and LDL levels.

MATERIALS AND METHODS

A cross-sectional study was conducted that included 7268 men who had participated in a health examination. Men who took agents that influence serum lipid profiles within the previous 6 months were excluded. A full metabolic work-up and serum testosterone level checks were performed. The main outcome measures included the testosterone level and testosterone <3.5 ng/ml prevalence of each decile of LDL and their polynomial trendlines and the odds ratio (OR) of testosterone <3.5 ng/ml according to the LDL level.

RESULTS

The polynomial trendline suggests the inverse association of testosterone with the deciles of triglycerides, the positive association of testosterone with the deciles of high-density lipoprotein cholesterol and the inverted U-shaped association between testosterone and the deciles of LDL. The polynomial trendline suggests a U-shaped curvilinear relationship between the deciles of LDL and the prevalence of testosterone <3.5 ng/ml. The adjusted ORs of testosterone <3.5 ng/ml in men in the lowest and highest deciles were significantly higher than those of men in the 10th-90th deciles of LDL (OR [95% CI], < 10th LDL: 1.4[1.2-1.8]; 10th - 90th LDL: 1.0 [reference]; >90th LDL: 1.3[1.0-1.6]), which reinforces the U-shaped curvilinear relationship between LDL levels and the prevalence of testosterone <3.5 ng/ml.

DISCUSSION AND CONCLUSION

Further research is needed to elucidate the association of very low or very high LDL concentrations with circulating testosterone in men.

Diagnostic work up: Laboratory and biomarkers

This chapter will focus on the diagnostic work around sexual dysfunction in Parkinson's disease, especially laboratory tests and biomarkers. A number of methods to analyze if sexual dysfunction is caused by neural pathology, vascular dysfunction or other mechanisms are now available. Other methods can be used to differentiate between psychogenic/functional reasons behind sexual dysfunction and organic ones. The role of biomarkers for diagnosis, but also for understanding the reason behind and for counteracting sexual dysfunction is becoming more evident. There is also a rich and increasing number of scales and other instruments available for detecting and quantifying sexual hypo- and hyperactivity. When investigating the reason behind sexual dysfunction in patients with Parkinson's disease comorbidities should also be considered. Finally, early and pronounced sexual dysfunction might in some cases be an indication that differential diagnosis, like Multisystem Atrophy, should be thought about. All these aspects of the diagnostic procedures around sexual dysfunction in Parkinson's disease will be covered in this chapter.

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.

Association between testosterone and lipid profiles under statin therapy and its clinical impact on the cardiovascular event risk

Statin therapy may decrease the levels of serum steroid hormones, including testosterone and cortisol, accompanied by lowering low-density lipoprotein cholesterol (LDL-C) levels, which remains to be investigated. The aim of this study is to examine the association between steroid hormones and lipids under statin therapy and its clinical impact on the cardiovascular event risk from a viewpoint of steroid hormone metabolism. Using a population dataset extracted from the standard versus intEnsive statin therapy for hyper-cholesteroleMic Patients with diAbetic retinopaTHY (EMPATHY) study, we analyzed the correlation between steroid hormones and lipid profiles at registration and 1 year after registration, comparing between male patients with or without cardiovascular events (CV events) within 4 years (CV events + ; n = 100, and CV events - ; n = 100, respectively) after prognostic score matching. The risk for CV events was evaluated using conditional logistic regression analysis. Testosterone levels were lower in the CV events + group than in the CV events - group at registration (5.2 ± 2.2 vs. 7.6 ± 4.1 ng/mL, p < 0.001). Testosterone levels were lowered to 5.1 ng/mL on average in proportion with LDL-C lowering, and Δtestosterone was correlated with ΔLDL-C during 1 year after registration. Cortisol levels were not correlated with LDL-C levels. In addition, testosterone levels at 1 year after registration were not associated with cardiovascular event risk. In male hypercholesterolemic patients with diabetic retinopathy, testosterone levels were positively correlated with LDL-C levels, which were mildly lowered in proportion with LDL-C lowering under mild statin therapy. This decrease in testosterone levels under statin therapy was not related to the increase in cardiovascular event risk.Clinical trial registration: UMIN 000003486. https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000004199.

EHD3 positively regulated by NR5A1 participates in testosterone synthesis via endocytosis

AIMS

Increasing evidence has shown that hormone secretion is regulated by endocytosis. Eps15 homology domain-containing protein 3 (EHD3) is an endocytic-trafficking regulatory protein, but whether EHD3 is associated with testosterone secretion is not clear. This work aims to explore the role of EHD3 in testosterone synthesis.

MAIN METHODS

Testosterone concentration was determined by ELISA. The effects of EHD3 on endocytosis were assessed by exosomes tracing assay and Immunofluorescence. Targeting relationship between EHD3 and NR5A1 was verified by chromatin immunoprecipitation (ChIP) and dual luciferase reporter gene assay in Leydig cells. For in vivo assessments, conditional NR5A1 knockout mouse model was established with CRISPR/Cas9 gene targeting technology.

KEY FINDINGS

EHD3 overexpression significantly increased the concentration of testosterone. EHD3 knockdown markedly decreased testosterone synthesis by reducing endocytosis. The activity of the EHD3 promoter was positively regulated by NR5A1, which occupied the conserved sequence "AGGTCA" in the EHD3 promoter. Furthermore, mice with a Leydig cell-specific conditional NR5A1 knockout displayed the blunted levels of EHD3 and clathrin (a key factor for endocytosis), and serum testosterone concentration compared with NR5A1^f/f mice.

SIGNIFICANCE

This study suggests a potential molecular mechanism of testosterone synthesis to fully understand male reproductive health.

Effects of "metabolic memory" on erectile function in diabetic men: A retrospective case-control study

OBJECTIVE

This study was performed to explore the effects of metabolic memory on diabetic erectile dysfunction (ED), especially the severity and response to treatment.

METHODS

Through medical records and follow-up by telephone, 67 patients meeting the criteria with a clinical diagnosis of ED and a diabetic history of more than 5 years were enrolled for erectile function analysis. They were divided into a glycemic control group, a glycemic non-control group and a metabolic memory group according to glycemic levels and treatments for diabetes in the past 5 years, and they were treated with phosphodiesterase type 5 (PDE5) inhibitors for 4 weeks. Erectile function and efficacy were assessed by the International Index for Erectile Function (IIEF), the Erection Hardness Score (EHS), and the Sexual Encounter Profile (SEP).

RESULTS

The patients in the glycemic control group performed better in erectile function than those in the other groups. The patients in the glycemic control group received a significantly greater score on both the EHS and the five domains of the IIEF than did the patients in the glycemic non-control group and the metabolic memory group (all P < .001). There were also statistically significant differences favoring the glycemic control group (P < .05) in SEP2 and SEP3 success rates. However, there were no significant differences between the metabolic memory group and the glycemic non-control group in these erectile function assessments (P > .05). Significant negative correlations were seen between HbA1c levels at the time of consultation and the scores on the IIEF-EF and the EHS (Pearson r-values of -0.338 with P = .005 and -0.273 with P = .025, respectively). HbA1c levels at the first diagnosis of diabetes mellitus (DM) were also significantly negatively correlated with scores on the IIEF-EF and the EHS with greater Pearson correlation coefficients (Pearson r-values of -0.478 with P < .001 and -0.392 with P = .001, respectively). Significant improvements on each of the erectile function assessments were observed among diabetic patients with ED, but no significant difference in efficacy was observed between each group.

CONCLUSIONS

The phenomenon of metabolic memory did have a significant influence on ED in men with diabetes, associated with the severity of ED but not the response to medical treatment. Early hyperglycemia exposure would have long-term disadvantageous effects on erectile function in diabetic patients with ED, which would be sustained even after the patients achieve better glycemic control.

PATIENTS SUMMARY

In this report, we looked at the erectile functions of 67 patients with a clinical diagnosis of ED and a diabetic history of more than 5 years. We found that early hyperglycemia exposure would have long-term disadvantageous effects on erectile function in diabetic patients with ED, which would be sustained even after the patients achieve better glycemic control. We further found that the effects were associated with the severity of ED but not the response to medical treatment in men with diabetes.

Causal Link Between Vitamin D and Total Testosterone in Men: A Mendelian Randomization Analysis

CONTEXT

Low circulating vitamin D levels have been associated with lower total testosterone levels. These epidemiological associations, if true, would have public health importance because vitamin D deficiency is common and correctable. We tested whether genetically lowered vitamin D levels were associated with lower total testosterone (T), using Mendelian randomization (MR) methodology.

DESIGN AND SETTING

A total of 4254 men were enrolled from the Survey on Prevalence in East China for Metabolic Diseases and Risk Factors (SPECT-China) study, which was performed at 23 sites in eastern China during 2014 to 2016. Using four single-nucleotide polymorphisms strongly associated with 25-hydroxyvitamin D [25(OH)D] levels, we created a genetic risk score (GRS) as an instrumental variable to estimate the effect of genetically lowered 25(OH)D on total T.

MAIN OUTCOME MEASURE

Total T was detected by chemiluminescence assay.

RESULTS

Lower 25(OH)D levels were associated with lower total T (β, 0.40; 95% CI, 0.23 to 0.58) after multivariable adjustment. Per-SD increase in the vitamin D GRS (VD_GRS) was significantly associated with 25(OH)D (β, -1.64; 95% CI, -2.04 to -1.24) and with total T (β, -0.19; 95% CI, -0.37 to -0.02). Using VD_GRS as the instrumental variable in the MR analysis, the causal regression coefficient of genetically determined per-SD increase for 25(OH)D on total T was 0.12 (95% CI, 0.02 to 0.22).

CONCLUSION

We provide evidence for the biologically plausible causal effects of 25(OH)D on total T using MR analysis. Whether vitamin D supplementation can raise androgen levels merits further investigation in long-term, randomized controlled trials.