Erectile dysfunction and diabetes: Association with the impairment of lipid metabolism and oxidative stress

The association between urinary organophosphate insecticide metabolites and erectile dysfunction in the United States

Organophosphate (OP) insecticides are the main chemicals used in agriculture for pest elimination, and they have been linked with many diseases. However, there is no literature regarding the impacts of organophosphate insecticide metabolite exposure on erectile dysfunction (ED). We aimed to evaluate the correlation between 4 urinary organophosphate insecticide metabolites and the presence of ED in a representative sample of men aged 20 and older. The dataset including a total of 555 subjects was obtained from the National Health and Nutrition Examination Survey (NHANES) 2003-2004. ED was assessed by a question from a self-report questionnaire. Weighted proportions and multivariable logistic regression analysis were utilized to examine the relationship between organophosphate insecticide metabolite exposure and ED. In multivariable logistic regression analysis, diethylphosphate (DEP) was positively correlated with ED (OR 1.07; 95% CI 1.01-1.14; P = 0.033) after full adjustment. Men in DEP tertile 4 had a significant 33% higher risk of ED than those in tertile 1. Furthermore, in a subgroup analysis, our results showed that higher DEP levels were significantly associated with ED in the young age group (20 ≤ age ≤ 39). Our study revealed a significant association between organophosphate insecticide metabolite exposure and an increased risk of ED. Moreover, the correlations were more evident in the young age group. The evaluation of urinary organophosphate insecticide metabolite exposure should be included in the risk assessment of ED. Further study to investigate the underlying mechanism, such as how long the urinary metabolite is present, whether ED is reversible in this population by lowering DEP concentrations, and how exposure to this metabolite affects erectile tissue, is warranted.

Comprehensive analysis of biological landscape of oxidative stress-related genes in diabetic erectile dysfunction

Oxidative stress plays a pivotal role in the pathogenesis of diabetic erectile dysfunction, while specific mechanisms have not been illuminated. The study aims to reveal the genetic expression patterns of oxidative stress in diabetic erectile dysfunction. Transcriptome data of diabetic erectile dysfunction and oxidative stress-related genes (OSRGs) in the Gene Expression Omnibus database were downloaded and analyzed based on differential expression. Functional enrichment analyses were conducted to clarify the biological functions. A protein interaction framework was established, and significant gene profiles were validated in the cavernous endothelial cells, clinical patients, and rat models. A miRNA-OSRGs network was predicted and validated. The results were analyzed using Student's t-test. The analysis screened 203 differentially expressed OSRGs (p < 0.05), which had a close association with oxidoreductase activities, glutathione metabolism, and autophagy. A four-gene signature comprised of EPS8L2 (p = 0.044), GSTA3 (p = 0.015), LOX (p < 0.001) and MGST1 (p = 0.002) was well validated and regarded as the hub OSRGs. Compared with the control group, notable increases and decreases were observed in the expressions of GSTA3 (3.683 ± 0.636 vs. 0.416 ± 0.507) and LOX (2.104 ± 1.895 vs. 18.804 ± 2.751) in the validated diabetic erectile dysfunction group. The hub OSRGs-related miRNAs participated in smooth muscle cell proliferation. Besides, miR-125a-3p (p = 0.034) and miR-138-2-3p (p = 0.012) were validated as promising oxidative stress-related miRNA biomarkers. Our findings revealed the genetic alternations of oxidative stress in diabetic erectile dysfunction. These results will be instructive to explore the molecular landscape and the potential treatment for diabetic erectile dysfunction.

Sexual Function and Satisfaction in the Context of Obesity

PURPOSE OF REVIEW

Sexual dysfunction is commonly associated with overweight/obesity, but the underlying physiological and psychosocial mechanisms are not fully understood. This review contextualizes the obesity-sexual (dys)function relationship, describes recent insights from the medical and social science literature, and suggests opportunities for continued research.

RECENT FINDINGS

Although sexual dysfunction has been historically evaluated as a consequence/outcome of obesity, it is increasingly considered as a harbinger of future metabolic comorbidities, including type 2 diabetes and cardiovascular disease. Body image dissatisfaction is a consistent predictor for lower sexual satisfaction across BMI categories, likely mediated by cognitive distraction during partnered sex. To fully capture the relationship between obesity and sexual dysfunction, multidisciplinary research approaches are warranted. While clinically significant weight loss tends to improve sexual functioning for women and men, higher body image satisfaction may independently promote sexual function and satisfaction without concomitant weight loss.

The Impact of Metabolic Syndrome Components on Erectile Function in Patients with Type 2 Diabetes

Erectile dysfunction is commonly encountered in diabetic patients and in patients with metabolic syndrome; however, only a few studies have assessed patients with metabolic syndrome and type 2 diabetes mellitus (T2DM) regarding their sexual function. The purpose of this study is to examine the effect of metabolic syndrome and its components on the erectile function of T2DM patients. A cross-sectional study including T2DM patients was conducted from November 2018 until November 2020. Participants were evaluated for the presence of metabolic syndrome and their sexual function was assessed using the International Index of Erectile Function (IIEF) questionnaire. A total of 45 consecutive male patients participated in this study. Metabolic syndrome was diagnosed in 84.4% and erectile dysfunction (ED) in 86.7% of them. Metabolic syndrome was not associated with ED or ED severity. Among metabolic syndrome components, only high-density lipoprotein cholesterol (HDL) was associated with ED [x² (1, n = 45) = 3.894, p = 0.048; OR = 5.5 (95% CI: 0.890-33.99)] and with the IIEF erectile function scores (median 23 vs. 18, U = 75, p = 0.012). Multiple regression analyses showed that HDL was non-significantly associated with the IIEF erectile function scores. In conclusion, among T2DM patients HDL is associated with ED.

Erectile Dysfunction Severity: The Role of Glycometabolic Compensation and Antihyperglycemic Drugs

Background: The aim of this study was to evaluate the prevalence of DM among patients with ED and the impact of glycometabolic compensation and antihyperglycemic treatment on ED severity. Methods: In total, 1332 patients with ED were enrolled. The diagnosis was performed through the International-Index-of-Erectile-Function questionnaire. ED severity was considered according to presence/absence of spontaneous erections, maintenance/achievement deficiency and response to PDE5-i. DM patients were clustered according to antihyperglycemic treatment: “metformin”/“insulin”/“old antihyperglycemic drugs”/“new antihyperglycemic drugs”. Results: The prevalence of DM patients was 15.8% (Group A, patients with ED and DM). Among these, the prevalence of spontaneous erections (21.0%) was lower than in the remaining patients (Group B, patients with ED without DM) (32.0%, p < 0.001). The prevalence of poor response to PDE5-i was lower in Group B (10.0%) than in Group A (35.0%, p < 0.001). Patients with good response to PDE5-i therapy showed lower HbA1c values than patients with poor/no response (6.6 ± 1.1% vs. 7.7 ± 1.9%, p = 0.02). The prevalence of absent response to PDE5-i was higher in patients treated with old antidiabetic drugs than in the population treated with new drugs (p = 0.03). Conclusion: The severity of ED and lower response to PDE5-i were higher in DM patients. A better glycometabolic profile, as well as new antihyperglycemic drugs, seem to have a positive effect on ED.

Employing biochemical biomarkers for building decision tree models to predict bipolar disorder from major depressive disorder

BACKGROUND

Conventional biochemical parameters may have predictive values for use in clinical identification between bipolar disorder (BD) and major depressive disorder (MDD).

METHODS

This study enrolled 2470 hospitalized patients with BD (n = 1333) or MDD (n = 1137) at reproductive age from 2009 to 2018 in China. We extracted 8 parameters, uric acid (UA), direct bilirubin (DBIL), indirect bilirubin (IDBIL), lactic dehydrogenase (LDH), free triiodothyronine (FT3), thyroid-stimulating hormone (TSH), high-density lipoprotein (HDL) and prealbumin of male, patients and 12 parameters, UA, DBIL, IBIL, LDH, FT3, TSH, glutamic-pyruvic transaminase (GPT), white blood cell (WBC), alkaline phosphatase (ALP), fasting blood glucose (FBG), triglyceride and low-density lipoprotein (LDL) of female patients. Backward stepwise multivariate regression analysis and the Chi-Square Automatic Interaction Detection (CHAID) segmentation analysis via SPSS Decision Tree were implemented to define the discrimination of BD and MDD.

RESULTS

DBIL was extracted as the first splitting variable, with LDH and IBIL as the second, TSH and prealbumin as the third in the model of male patients (p-value < .05). For the model of female patients, DBIL was also extracted as the first splitting variable, with UA, LDH, and IBIL as the second, triglyceride and FT3 as the third (p-value < .05). The predictive accuracies of the Decision Tree and multiple logistic regression models were similar (74.9% vs 76.9% in males; 74.4% vs 79.5% in females).

CONCLUSIONS

This study suggests the value of the Decision Tree models, which employ biochemical parameters as diagnostic predictors for BD and MDD. The CHAID Decision Tree identified that patients with concomitantly increased LDH, IBIL, and decreased DBIL could be in the group that showed the highest risk of being diagnosed as BD.

Trigonella foenum-graecum L. and Psoralea corylifolia L. Improve Erectile Dysfunction in Streptozotocin-Induced Diabetic Rats through Suppression of Oxidative Stress

Background

Diabetes mellitus-induced erectile dysfunction (DMED) is one of the most common complications of diabetes and is mainly attributed to oxidative stress. Hu-Lu-Ba-Wan (HLBW) is a classic Chinese formulation consisting of Trigonella foenum-graecum L. (TFG) and Psoralea corylifolia L. (PC). HLBW has been used not only for the treatment of diabetes but also for the treatment of erectile dysfunction in clinics. This study aimed to explore the efficacy and underlying mechanism of HLBW in ameliorating erectile function in streptozotocin-induced diabetic rats.

Methods

The diabetic model was established by tail vein injection of streptozotocin (26 mg/kg), and then DMED rats screened by the apomorphine test were randomly divided into two groups: the model group and the HLBW group. The rats in the HLBW group were administered HLBW granules daily for 12 weeks. Fasting blood glucose and fasting insulin were tested by a commercial kit. Intracavernous pressure (ICP) and mean arterial pressure (MAP) were measured by cavernous nerve electrostimulation before the rats were killed. Erectile function was evaluated with ICP/MAP. The markers of oxidative stress in the corpus cavernosum (CC) were assayed by assay kits. Apoptosis in cavernosal tissue was detected by Western blotting (WB). The expression levels of vascular endothelial marker (vWF), α-smooth muscle actin (α-SMA), endothelial nitric oxide synthase (eNOS), and NADPH oxidase subunit P47^phox were determined by WB and PCR. Furthermore, the structure of the CC was further confirmed by Masson's trichrome staining.

Results

The results showed that HLBW significantly reduced blood glucose and increased insulin sensitivity. HLBW reduced oxidative stress and apoptosis. In addition, we observed that the expression levels of vWF, α-SMA, and eNOS as well as the ratio of smooth muscle to collagen increased in the HLBW group.

Conclusions

Our results demonstrated that HLBW could reduce oxidative stress damage in CC to improve diabetes mellitus-induced erectile dysfunction in rats by inhibiting NADPH oxidase.

Prevalence and associated factors of erectile dysfunction in men with type 2 diabetes mellitus in eastern Sudan

BACKGROUND

Diabetes mellitus (DM) is a global health threat and burden that is associated with many chronic complications. Erectile dysfunction (ED) among patients with DM is one of these complications. There is no published data on ED in Sudan; hence, we conducted this study to evaluate the prevalence of ED and the associated factors in patients with type 2 diabetes mellitus (T2DM) in eastern Sudan.

METHODS

We performed a cross-sectional study. Data on blood glucose level, cholesterol level, anthropometric and demographic characteristics, results of the International Index of Erectile Function (IIEF-5) questionnaire, and clinical history were obtained.

RESULTS

A total of 334 men with T2DM with a median (interquartile range [IQR]) age of 55.0 (±10.0) years were enrolled in the study. The median (IQR) of the duration of DM was 7.0 (±8) years, and 260 (77.8%) had uncontrolled T2DM. The median (IQR) body mass index was 24.5 (±4.9) kg/m2. Of the participants, 81 (24.3%) had severe ED, 52 (15.6%) had moderate ED, 75 (22.5%) had mild to moderate ED, and 63 (13.9%) had mild ED. Of the 334 men, 271 (81.1%) had ED. Logistic regression analysis showed that age (adjusted Odds Ratio [AOR] = 1.07, 95% confidence interval [CI] = 1.01-1.14), duration of DM (AOR = 1.26, 95% CI = 1.06-1.51), and cholesterol levels (AOR = 3.53, 95% CI = 1.75-7.11) were positively associated with ED. Moreover, poor glycaemic control (AOR = 3.38, 95% CI = 1.70-6.71, P < 0.001) was significantly associated with ED.

CONCLUSION

There is a high prevalence of ED among patients with T2DM in eastern Sudan. Age, duration of DM, and cholesterol were positively associated with ED.

Cysteine-Rich Whey Protein Isolate (CR-WPI) Ameliorates Erectile Dysfunction by Diminishing Oxidative Stress via DDAH/ADMA/NOS Pathway

Nitric oxide synthase- (NOS-) dependent endothelial dysfunction induced by oxidative stress (OS) is assumed to play a pivotal role in the pathogenesis and progression of diabetes mellitus-related erectile dysfunction (DMED). Cysteine-rich whey protein isolate (CR-WPI) is a widely used protein supplement and has been confirmed to reduce reactive oxygen species (ROS) by increasing cellular antioxidant glutathione (GSH). However, it is currently unknown whether CR-WPI elicits therapeutic effects in DMED. Here, we provide diabetic rats with CR-WPI to determine its effect on DMED and the underlying mechanisms. The results suggest that CR-WPI supplementation increased GSH biosynthesis and reduced ROS content and simultaneously upregulated the dimethylarginine dimethylaminohydrolase (DDAH)/asymmetrical dimethylarginine (ADMA)/nitric oxide synthase (NOS) metabolic pathway. Evaluation of intracavernous pressure (ICP) also showed an improvement of penile erectile function in CR-WPI-treated rats. The results of the vitro cell culture showed that glutathione pretreatment protected corpus cavernosum smooth muscle cells (CCSMC) from H₂O₂-induced apoptosis by decreasing Caspase 9 and Caspase 3 expressions. These results augur well for the potential therapeutic application of dietary CR-WPI supplementation for treating diabetic erectile dysfunction.

Erectile dysfunction and diabetes: A melting pot of circumstances and treatments

Diabetes mellitus (DM), a chronic metabolic disease characterised by elevated levels of blood glucose, is among the most common chronic diseases. The incidence and prevalence of DM have been increasing over the years. The complications of DM represent a serious health problem. The long-term complications include macroangiopathy, microangiopathy and neuropathy as well as sexual dysfunction (SD) in both men and women. Erectile dysfunction (ED) has been considered the most important SD in men with DM. The prevalence of ED is approximately 3.5-fold higher in men with DM than in those without DM. Common risk factors for the development of DM and its complications include sedentary lifestyle, overweight/obesity and increased caloric consumption. Although lifestyle changes may help improve sexual function, specific treatments are often needed. This study aims to review the definition and prevalence of ED in DM, the impact of DM complications and DM treatment on ED and, finally, the current and emerging therapies for ED in patients with DM.

Probucol enhances the therapeutic efficiency of mesenchymal stem cells in the treatment of erectile dysfunction in diabetic rats by prolonging their survival time via Nrf2 pathway

BACKGROUND

Intracavernous injection of mesenchymal stem cells (MSCs) is a promising method for diabetic mellitus-induced erectile dysfunction (DMED), but short survival time of MSCs in cavernous is a fatal defect for therapy. This study investigated therapeutic efficiency and potential mechanism of probucol combined with MSCs.

METHODS

In vivo study, a total of forty-eight 10-week-old male Sprague-Dawley (SD) rats were used. Twelve rats received intraperitoneal injection of PBS as the sham group; the rest received intraperitoneal injection of 60 mg/kg streptozotocin to establish DM models. DM rats were randomly divided into three groups: received intracavernosal (IC) injection of either PBS (DM group), MSCs (M group), or administrated probucol after intracavernosal injection of MSCs (P + M group). Erectile function was assessed by electrical stimulation of the cavernous nerves with real-time intracavernous pressure measurement. After euthanasia, penile tissue was investigated for histologic examination and Western blotting. In in vitro experiment, H2O2 was used to create oxidative stress environment to detect changes in cell viability. CCK8 was used to measure cell viability of MSCs treated with or without probucol. Intracellular ROS changes were detected by flow cytometry. Autophagy and apoptosis were detected by Western blotting and confocal microscopy.

RESULTS

Recovery of erectile function was observed in the P + M group. The combination therapy decreased fibrosis and increased endothelial function compared with MSC therapy alone. Western blotting results confirmed the increased expression of Nrf2 and HO-1 in cavernous body. H2O2 induced high oxidative stress and reduced cell viability in vitro, which was gradually reversed with increased concentration of probucol. H2O2 reduced Nrf2 expression, which was reversed by probucol's intervention. Furthermore, the expression of Bax, Caspase3, and Cleaved-Caspase3 decreased, and the expression of Bcl-2 increased in a dose-dependent manner because of probucol's intervention. In addition, Beclin1 and LC3II both increased in a dose-dependent manner. Meanwhile, the expression of P62 decreased. In the study of autophagy flux, we found probucol did not block it.

CONCLUSION

Probucol enhanced therapeutic efficiency of MSCs in DMED by prolonging their survival time, which mediated through improving the transplanted microenvironment of MSCs, increasing self-antioxidant ability of MSCs, strengthening protective autophagy, and inhibiting apoptosis of MSCs via Nrf2 pathway. Schematic model showing combined probucol and MSCs to improve DMED. Probucol increases self-antioxidant ability of MSCs, strengthening protective autophagy and inhibiting apoptosis via Nrf2/HO-1 and Nrf2/autophagy pathways.

Impact of diabetes on male sexual function in streptozotocin-induced diabetic rats: Protective role of soluble epoxide hydrolase inhibitor

Diabetes-induced male sexual dysfunction is associated with endothelial dysfunction. Inhibition of soluble epoxide hydrolase (sEH) is known to improve endothelial function in diabetes. Therefore, we hypothesized that sEH inhibitor (sEHI), [trans-4-{4-[3-(4-trifluoromethoxyphenyl)-ureido]cyclohexyloxy}benzoic acid] / t-TUCB can restore the male sexual function in diabetic rat. After one week of administration of diabetogenic agent STZ (52 mg/kg i.p) injection, diabetic rats were treated with t-TUCB (0.1 and 0.3 mg/kg, p.o) or vehicle for 8 weeks. The sexual behaviour parameters of the animals were evaluated at the end of dosing period. The levels of testosterone and glucose in serum, and sperm were quantified. Effect of treatment on weight of reproductive organs and histopathology of penile tissue was evaluated. Diabetes had a negative effect on male sexual function, weight of sexual organs and production of sperm with a parallel decrease in the level of testosterone. The sEHI, t-TUCB, significantly preserved the sexual function and minimized an increase in the level of blood glucose in diabetic rats. It also prevented a decrease in the level of testosterone and sperm in diabetic rats, in comparison to diabetic control rats. Further, diabetes induced distortion of corpus cavernosum was attenuated by t-TUCB. Based on our findings, sEHI may delay the development of sexual dysfunction in diabetes.

Combination of mesenchymal stem cell injection with icariin for the treatment of diabetes-associated erectile dysfunction

The present study was aimed to examine whether icariin, a traditional Chinese medicine, could improve therapeutic effects of adipose derived mesenchymal stem cells (ADSCs) for diabetes-associated erectile dysfunction (DMED). DMED were induced in rats by intraperitoneal injection of streptozotocin and confirmed by erectile function measurement. Then, rats of diabetic ED were randomly divided to receive the treatment of saline, ADSCs, icariin or ADSCs combined with icariin respectively. Compared with the treatment by ADSCs or icariin alone, intracavernosum injection of ADSCs combined with the following daily gastric gavage of icariin significantly augmented the value of ICP and ICP/MAP (p<0.01). Meanwhile, the survival of transplanted ADSCs was much improved due to the application of icariin. Similarly, immunofluorescent staining analysis demonstrated that the improved erectile tissue structure by combination of ADSCs and icariin was significantly associated with the increased expression of endothelial markers (vWF) (p<0.01) and smooth muscle markers (α-SMA) (p<0.01). Furthermore, the structure changes in corpus cavernosum were further confirmed by the Masson’s trichrome staining. To explore the possible mechanism underlying icariin-enhanced therapeutic efficacy of MSCs, we employed an in vitro testing system by introducing H₂O₂ to imitate oxidative stress condition considering the oxidative environment faced by engrafted ADSCs and anti-oxidative capacity of icariin_.In vitro, we found that the addition of icariin considerably reduced the apoptosis of ADSCs, and attenuated the intracellular reactive oxygen species (ROS), the superoxidase dismutase (SOD) activity and the lactate dehydrogenase (LDH). Subsequently, we examined the expression of apoptosis-related proteins and explored the potential signaling pathway through which icariin promoted the survival of ADSCs against oxidative stress. It was demonstrated that icariin significantly inhibited the upregulation of apoptosis-related proteins under oxidative condition, including Bax and cleaved caspase-3, while promoted the expression of anti-apoptotic factor BCL2. These effects were accompanied with the activation of signal molecules, PI3K/Akt and STAT3. The further signal protein inhibition assays exhibited that the suppression of STAT3 abrogated the icariin-mediated anti-apoptotic effects observed above, while did not influence the expression of PI3K/Akt. However, PI3K inhibition could abrogate icariin–mediated STAT3 activation and achieved a similar effect as STAT3 inhibition. Our results suggested that icariin was an effective adjuvant for enhancing ADSC-based therapy of DMEM, which may be ascribed to their protection of ADSCs against oxidative stress via the regulation of PI3K/Akt-STAT3 signal pathway.