Effects of metformin on endothelial health and erectile dysfunction

Prevalence and predictors of erectile dysfunction among men in the diabetes prevention program outcomes study

OBJECTIVE

To determine burden and identify correlates of erectile dysfunction (ED) among men with prediabetes (PreD) and type 2 diabetes (T2D) enrolled in the Diabetes Prevention Program (DPP) Outcomes Study (DPPOS).

RESEARCH DESIGN AND METHODS

The 2017 DPPOS visit included administration of the International Index of Erectile Function. Of 648 male participants, 88 % (n = 568) completed the survey. Associations between sociodemographic, behavioral, clinical, and glycemic measures at time of ED assessment, and ED were examined using multivariable logistic regression models in men with PreD and T2D separately.

RESULTS

Overall, 218 (38 %) men met ED criteria. Prevalence was similar in men with PreD (41 %) and T2D (37 %) (p = 0.4). In all men, age (p < 0.001) increased odds of ED. Among men with PreD, those assigned to intensive lifestyle intervention (ILS), but not metformin, had decreased odds of ED compared with the placebo group (OR = 0.35, 95 % CI = 0.13, 0.94). Non-Hispanic White race was associated with increased odds of ED compared with other races (OR = 4.3; 95 % CI = 1.92, 9.65). Among men with T2D, ED risk did not differ by DPP treatment assignment; however, individuals with metabolic syndrome defined by National Cholesterol Education Program criteria, had increased odds of ED (OR = 1.85, 95 % CI = 1.14, 3.01), as did individuals with depression (OR = 2.05; 95 % CI = 1.10, 3.79).

CONCLUSIONS

ED is prevalent in men with PreD and T2D. Our finding of reduced odds of ED in men randomized to ILS and with PreD suggests a potential opportunity for risk mitigation in the prediabetes interval. In men who have progressed to T2D, metabolic factors appear to be associated with ED.

Can atherogenic indices and the triglyceride-glucose index be used to predict erectile dysfunction?

Background

Atherosclerosis and insulin resistance play an important role in the development of erectile dysfunction (ED), and few studies have comprehensively evaluated more specific indicators like atherogenic indices and the triglyceride-glucose (TyG) index in the assessment of ED.

Aim

This study aimed to reveal the role of atherogenic indices (atherogenic index of plasma [AIP], Castelli risk index-1/2 [CRI-1/2], and atherogenic coefficient [AC]) based on plasma lipid ratios, which have been used as more sensitive indicators of atherosclerosis in recent years, and the TyG index, a practical indicator of insulin resistance, in predicting vasculogenic ED.

Methods

The study included a total of 199 patients who met the inclusion criteria and a total of 51 control subjects without ED complaints according to the International Index of Erectile Function (IIEF-5) scores (>21) between May 2021 and October 2022. For all participants, the demographic and biochemical parameters were evaluated, and atherogenic indices, namely CRI-1 (total cholesterol/high-density lipoprotein [HDL]), CRI-2 (LDL/HDL) AIP [log10(triglycerides/HDL)], and AC (non-HDL/HDL), as well as the TyG index [Ln {fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2}] were calculated.

Outcomes

The TyG index, which is an indicator of insulin resistance, and atherogenic indices such as CRI-1, AIP, and AC were significantly associated with ED, and especially AIP and the TyG index seem to be more important in the evaluation of ED.

Results

According to the univariate analysis, the patient group had significantly higher CRI-1 (5.3 ± 1.4 vs 4.7 ± 1.3; P = .005), AIP (0.31 ± 0.26 vs 0.13 ± 0.2; P < .001), AC (4.1 ± 1.4 vs 3.70 ± 1.2; P = .026), and TyG (9.16 ± 0.71 vs 8.77 ± 0.52; P < .001) values compared with the control group. In the correlation analysis, a significant negative correlation was found between the AIP and TyG index and the IIEF-5 scores (r2 = 0.120, P < .001 between AIP and IIEF-5; r2 = 0.091, P < .001 between TyG index and IIEF-5). The multivariate analysis revealed AIP and the TyG index as independent predictive factors for ED.

Clinical Implications

The use of atherogenic indices and TyG index in daily urology practice can help physicians in the diagnosis and follow-up of ED.

Strengths and Limitations

The lack of sex hormone-binding globulin and free testosterone levels represents a limitation of our study. Another limitation is that the severity of ED was determined using the IIEF-5 scores, rather than a more objective method, such as penile artery ultrasound.

Conclusion

Atherogenic indices and the TyG index can be used as inexpensive and practical markers to predict the severity of arteriogenic ED.

Effects of diet and antihyperglycemic drugs on erectile dysfunction: A systematic review

BACKGROUND

Erectile dysfunction is recognized as one of the complications of diabetes mellitus. To date, a wide gap of knowledge is present on the efficacy of pharmacological treatments of diabetes mellitus on erectile function, acting not only through metabolic control. Similarly, the effects of different diet regimens on erectile dysfunction are still debated.

OBJECTIVES

We aimed to explore the effects of diet and antihyperglycemic drugs, considering both old and novel therapeutic approaches, on erectile function.

MATERIALS/METHODS

We performed a systematic review, following the PRISMA guidelines. The research was conducted on studies reporting erectile dysfunction assessment in subjects with diabetes and the relationship with diet and antihyperglycemic drugs.

RESULTS

The Mediterranean diet was effective in most studies for the protection of erectile function. Furthermore, antihyperglycemic drugs seem to show an overall protective role on erectile function.

DISCUSSION/CONCLUSION

Although encouraging results are present for all classes of antihyperglycemic drugs, several studies are needed in humans, mainly on acarbose, pioglitazone, dipeptidyl-peptidase-4 inhibitors, and sodium-glucose cotransporter-2 inhibitors.

Grapefruit peel extract mitigates paroxetine-induced erectile dysfunction in rats through stimulation of erectile response, antioxidant status, and inhibition of key enzymes related with impaired penile erection

Despite the antidepressant potency of paroxetine, its side effect of erectile dysfunction is burdensome. Grapefruit peels (GFPs) are underutilized cultivar wastes with wide range of therapeutic potentials which have been attributed to their antioxidant behavior and phenolic contents' abilities to effectively inhibit enzymatic activities and manage endothelial dysfunction in cardiovascular disorders. This study aims to investigate the erectogenic potentials of GFP extract in a rat model of paroxetine-induced ED. Experimental rats were sectioned into five groups: [1: control; 2: paroxetine (10 mg/kg); 3: paroxetine + sildenafil (5 mg/kg); 4: paroxetine + GFP (50 mg/kg); 5: paroxetine + GFP (100 mg/kg)] and treated for 28 days. Sexual behavior of rats was assessed and effect of GFP on ecto-5' nucleotidases, phosphodiesterase-5, and adenosine deaminase (ADA) activities was determined in rats' penile tissues. The levels of malondialdehyde, nitric oxide (NO) as well as superoxide dismutase (SOD) and catalase activities were also determined. HPLC-DAD analysis showed the presence of naringin, rutin, caffeic acid, quercitrin, quercetin, and kaempferol glycoside. Oral administration of paroxetine reduced erectile response as revealed by their low intromission and mounting numbers as well as high intromission and mounting latencies. Paroxetine caused a significant elevation of ADA and phosphodiesterase-5 activities and malondialdehyde levels with drastic reduction in levels of NO, SOD, and catalase activities in rats' penile tissues. However, GFP extract reversed PDE-5, ADA, and antioxidant activities to normal levels, raised the concentration of NO. These results suggest the erectogenic effects and protective potentials of GFP extract against paroxetine-induced erectile dysfunction. PRACTICAL APPLICATION: Grapefruit peels are an environmental menace in many countries and this study showed that the peels can be used in the prevention / management of erectile dysfunction. The therapeutic potentials of the peels are due to the presence of bioactive compounds such as flavonoids and phenolic acids. Therefore, exploring the erectogenic potentials of the peels will translate to conversion of the wastes to therapeutic products.

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.

Hypothalamic-pituitary-gonadal axis and sexual functioning in metformin-treated men after discontinuation of testosterone replacement therapy: A pilot study

WHAT IS KNOWN AND OBJECTIVE

Metformin was found to reduce elevated gonadotropin levels. The aim of the present study was to determine whether metformin modulates the impact of discontinuation of testosterone therapy on hypothalamic-pituitary-gonadal axis activity and sexual function in men with low testosterone levels.

METHODS

The study included 28 men with late-onset hypogonadism (defined according to the criteria of the European Male Aging Study group) receiving testosterone undecanoate (120 mg in three equal doses), 12 of whom had been treated with oral metformin (1.7-3 g daily). Both testosterone and metformin had been administered for at least six months before enrolment. In all patients, testosterone replacement required to be discontinued. The control group included 16 testosterone- and metformin-treated men with late-onset hypogonadism who during the entire study period continued their treatment. Glucose homeostasis markers, as well as plasma levels of insulin, gonadotropins, testosterone, calculated bioavailable testosterone, dehydroepiandrosterone-sulphate, oestradiol, thyrotropin, free thyroxine, prolactin, insulin-growth factor-1 and cortisol were measured at the beginning of the study and four months later. Moreover, at the beginning and the end of the study, all enrolled patients completed a questionnaire assessing their sexual functioning (IIEF-15).

RESULTS AND DISCUSSION

Discontinuation of testosterone therapy resulted in a decrease in total testosterone and bioavailable testosterone (by 42% and 45% in metformin-treated patients, and by 52% and 54% in metformin-naïve patients), as well as impaired all aspects of male sexual function. Changes in bioavailable testosterone, as well as in erectile function, orgasmic function and sexual desire were less pronounced if subjects received metformin. Only in metformin-naïve men, follow-up FSH and LH levels were higher than at baseline (by 75% and 62%). Moreover, discontinuation of testosterone therapy in metformin-naïve men increased glycated haemoglobin, as well as worsened insulin sensitivity. There were no differences between baseline and follow-up levels of the remaining hormones. In metformin-naïve subjects, the increase in gonadotropin levels correlated with the changes in testosterone levels and insulin sensitivity. No effect on glucose homeostasis markers, hormone levels and sexual functioning was observed in the control group.

WHAT IS NEW AND CONCLUSION

The obtained results suggest that metformin treatment mitigates the unfavourable effect of discontinuation of testosterone treatment on hypothalamic-pituitary-testicular axis activity and sexual function in men with late-onset hypogonadism.

Predicting risk of erectile dysfunction in patients with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the risk factors for erectile dysfunction (ED). We aimed to predict the risk of ED in patients with NAFLD. The study included 146 male patients complaining impotence admitted to the urology outpatient clinic aged 24-80 years without a history of alcohol use who underwent abdominal ultrasonography between February 2018 and January 2019. 106 patients with NAFLD and 40 men without NAFLD were included in the study. Clinical and laboratory parameters, ED status according to International Index of Erectile Function-5 were compared between patients with and without NAFLD. The mean age of patients was 51.47 ± 10.34 years. NAFLD was detected in 72.6% of the patients. No statistically significant difference was found regarding mean age, BMI, IIEF-5 scores, DM status, serum glucose levels (p > .05). Fasting insulin levels, hypertension (HT), insulin resistance (IR) and ED status of the patients with NAFLD were significantly higher than patients without NAFLD (p < .05). NAFLD was found to be a significantly independent associated with ED. We also found that patients with NAFLD have risk of ED 2.92 times higher than without NAFLD (OR: 2.92). For the patients presenting with erectile dysfunction, hepatic steatosis should also be considered.

The Effect of Metformin on Male Reproductive Function and Prostate: An Updated Review

Metformin is the first-line oral antidiabetic drug that shows multiple pleiotropic effects of anti-inflamation, anti-cancer, anti-aging, anti-microbia, anti-atherosclerosis, and immune modulation. Metformin's effects on men's related health are reviewed here, focusing on reproductive health under subtitles of erectile dysfunction (ED), steroidogenesis and spermatogenesis; and on prostate-related health under subtitles of prostate specific antigen (PSA), prostatitis, benign prostate hyperplasia (BPH), and prostate cancer (PCa). Updated literature suggests a potential role of metformin on arteriogenic ED but controversial and contradictory effects (either protective or harmful) on testicular functions of testosterone synthesis and spermatogenesis. With regards to prostate-related health, metformin use may be associated with lower levels of PSA in humans, but its clinical implications require more research. Although there is a lack of research on metform's effect on prostatitis, it may have potential benefits through its anti-microbial and anti-inflammatory properties. Metformin may reduce the risk of BPH by inhibiting the insulin-like growth factor 1 pathway and some but not all studies suggest a protective role of metformin on the risk of PCa. Many clinical trials are being conducted to investigate the use of metformin as an adjuvant therapy for PCa but results currently available are not conclusive. While some trials suggest a benefit in reducing the metastasis and recurrence of PCa, others do not show any benefit. More research works are warranted to illuminate the potential usefulness of metformin in the promotion of men's health.

Analysis of pharmacological mechanisms of Yinyanghuo as treatment of erectile dysfunction with network pharmacology-based strategy

Erectile dysfunction is considered an important health problem that impacts the quality of life of men. Yinyanghuo, also called Epimedium or Horny Goat Weed, is a frequently used Chinese traditional herbal medicine, commonly used in treating erectile dysfunction in China. A network pharmacology method was performed systematically, at a molecular level, to analyse the pharmacological mechanism of Yinyanghuo as erectile dysfunction therapy. The network pharmacology method used in this study primarily includes prescreening of the active compounds, prediction of targets, network analysis and gene enrichment analysis. This network analysis proved that 4 targets (AR, NR3C2, PDE5A and BMP2) could be the targets of Yinyanghuo therapy on erectile dysfunction. Besides, gene enrichment analysis predicted that Yinyanghuo might have a role in erectile dysfunction by regulating 10 molecular functions, 8 cellular components, 10 biological processes and 36 possible targets related to 10 signalling pathways. Our study demonstrated the molecular and pharmacological mechanisms of Yinyanghuo against erectile dysfunction with a holistic approach and demonstrated a powerful method for analysing pharmacological mechanisms and rational utilisation of Traditional Chinese Medicine clinically.

Triglyceride-Glucose Index (TyG) is associated with erectile dysfunction: A cross-sectional study

BACKGROUND

Erectile dysfunction (ED) is often associated with endocrine metabolic diseases such as metabolic syndrome (MetS) and diabetes mellitus (DM), in which insulin resistance (IR) plays a decisive role in pathology. Triglyceride-glucose index (TyG), a simple, inexpensive and easily accessible IR marker, is calculated by fasting serum glucose and triglyceride values.

OBJECTIVES

We aimed to reveal the relationship between TyG index and ED.

MATERIALS AND METHODS

Of 152 male patients, aged between 24-80 years, admitted to the urology outpatient clinic with complaining erectile insufficiency were evaluated. Liver function tests, complete blood count, fasting serum triglyceride, serum testosterone, fasting glucose, fasting insulin, and hemoglobinA1c (HbA1c) were analyzed. TyG index was calculated. All patients were requested to fill in the validated Turkish version of the 5-item International Index of Erectile Function (IIEF-5) survey.

RESULTS

A total of 142 patients were included the study. ED was detected in 91 (64.1%) of the patients. BMI, fasting insulin level, fasting glucose level, IR, GGT, HDL, HbA1c, Triglyceride, TyG, DM, HT, and MetS status of the patients in ED group were statistically significantly higher compared to non-ED group (all P < .05). It was found that the cutoff value of TyG index for ED was 8.88 (AUC = 0.739, sensitivity 67%, specificity = 68.6%). In multivariate logistic regression analysis, age (OR = 1.07, 95% CI = 1026-1115, P = .002) and TyG index above 8.88 (OR = 3.865, 95% CI = 1686-8859, P = .001) were found as independent predictors of ED after accounting for BMI, serum total T and IR.

CONCLUSION

TyG index might be useful in the diagnosis and follow-up of ED.

Metformin-induced anticancer activities: recent insights

Metformin is a widely used antidiabetic drug, and there is evidence among diabetic patients that metformin is a chemopreventive agent against multiple cancers. There is also evidence in human studies that metformin is a cancer chemotherapeutic agent, and several clinical trials that use metformin alone or in combination with other drugs are ongoing. In vivo and in vitro cancer cell culture studies demonstrate that metformin induces both AMPK-dependent and AMPK-independent genes/pathways that result in inhibition of cancer cell growth and migration and induction of apoptosis. The effects of metformin in cancer cells resemble the patterns observed after treatment with drugs that downregulate specificity protein 1 (Sp1), Sp3 and Sp4 or by knockdown of Sp1, Sp3 and Sp4 by RNA interference. Studies in pancreatic cancer cells clearly demonstrate that metformin decreases expression of Sp1, Sp3, Sp4 and pro-oncogenic Sp-regulated genes, demonstrating that one of the underlying mechanisms of action of metformin as an anticancer agent involves targeting of Sp transcription factors. These observations are consistent with metformin-mediated effects on genes/pathways in many other tumor types.

The Relationship of the TLR9 and TLR2 Genetic Polymorphisms with Cervical Cancer Risk: a Meta-Analysis of Case-Control Studies

This meta-analysis aimed to assess the association of common TLR9 and TLR2 gene polymorphisms (TLR9 1486 T/C, TLR9 G2848A, and TLR2-196 to -174 del/ins) with cervical cancer risk. Studies were searched in Scopus, Pubmed, Embase, and CNKI until December 2017. Both fixed-effects and random-effects models were applied to combine odds ratio (OR) and 95% confidence intervals (95% CI). A total of 11 studies including 7856 participants were identified. The pooled estimation revealed an increased risk of cervical cancer in Caucasian subjects carrying the C allele of the TLR9 1486 T/C polymorphism (OR = 1.46, 95% CI: 1.11-1.92, p = 0.007), while there was a decreased risk in Mixed subjects carrying the C allele (OR = 0.35, 95% CI: 0.15-0.82, p = 0.016). Concerning the TLR9 G2848A polymorphism, the A allele was associated with an increased risk of cervical cancer in Caucasians (OR = 1.19, 95% CI: 1.02-1.40, p = 0.030), whereas Asian and Mixed subjects showed no significant associations. No significant associations were demonstrated between the TLR2-196 to -174 del/ins polymorphism and cervical cancer. Our findings suggest that the TLR9 1486 T/C and G2848A polymorphisms contribute to cervical cancer risk, but there is no association of the TLR2-196 to -174 del/ins polymorphism with cervical cancer.

Obesity and Erectile Dysfunction: From Bench to Clinical Implication

Obesity is a major public health issue worldwide and is frequently associated with erectile dysfunction (ED). Both conditions may share an internal pathologic environment, also known as common soil. Their main pathophysiologic processes are oxidative stress, inflammation, and resultant insulin and leptin resistance. Moreover, the severity of ED is correlated with comorbid medical conditions, including obesity. Therefore, amelioration of these comorbidities may increase the efficacy of ED treatment with phosphodiesterase 5 inhibitors, the first-line medication for patients with ED. Although metformin was originally developed as an insulin sensitizer six decades ago, it has also been shown to improve leptin resistance. In addition, metformin has been reported to reduce oxidative stress, inflammatory response, and body weight, as well as improve ED, in animal and human studies. Moreover, administration of a combination of metformin and phosphodiesterase 5 inhibitors improves erectile function in patients with ED who have a poor response to sildenafil and are insulin resistant. Thus, concomitant treatment of metabolic derangements associated with obesity in patients with ED who are obese would improve the efficacy and reduce the refractory response to penile vasodilators. In this review, we discuss the connecting factors between obesity and ED and the possible combined treatment modalities.