Is Type 2 Diabetes Mellitus a Cause of Severe Erectile Dysfunction in Patients With Metabolic Syndrome?

Evaluation of serum irisin level and severity of erectile dysfunction in diabetic males: a cross sectional prospective study

BACKGROUND

Irisin is an exercise-induced myokine that alleviates endothelial dysfunction and reduces insulin resistance in type 2 diabetes mellitus (T2DM). The current study aimed to assess the serum level of irisin in T2DM men with erectile dysfunction (ED) compared to T2DM patients with normal erectile function and healthy controls, as well as investigate the association between serum irisin level and the severity of ED in T2DM patients.

PATIENTS AND METHODS

A cross-sectional study was conducted on 90 males, divided into three groups: 32 T2DM patients with ED, 24 T2DM patients without ED, and 34 healthy controls. Socio-demographic characteristics and scores of the validated Arabic version of the international Index of Erectile Function-5 (ArIIEF-5), Generalized Anxiety Disorder-7 (GAD-7) and Patient Health Questionnaire-9 (PHQ-9) were obtained. Furthermore, routine laboratory tests employed for diabetes monitoring and serum levels of total testosterone and irisin were assessed within these groups.

RESULTS

T2DM men with ED had significantly lower serum levels of irisin and testosterone, as well as a lower ArIIEF-5 score, but their GAD-7 and PHQ-9 scores were significantly higher than those without ED or controls (p < 0.001). Among T2DM men, serum irisin levels positively associated with ArIIEF-5 scores and serum testosterone (r = 0.413, p = 0.002; r = 0.936, p < 0.001, respectively) but negatively associated with glycosylated hemoglobin levels (r = -0.377, p = 0.004). Multivariate regression analysis to predict ED in T2DM patients found that GAD-7 score was the only most significant predictor for ED (ꞵ = - 1.176, standard error = 0.062, p < 0.001).

CONCLUSION

The current study had demonstrated that irisin positively correlated with the ArIIEF-5 and serum testosterone but negatively correlated with HbA1c in T2DM men. Nevertheless, further validation of these findings is necessary through cohort studies.

Uncovering the Potential Mechanisms and Effects of Hyperuricemia and its Associated Diseases on Male Reproduction

Male fertility and metabolic disorders, including obesity and diabetes, are closely connected. Since hyperuricemia and metabolic syndrome are strongly related, male fertility and hyperuricemia may, to some degree, be associated. According to recent studies, hyperuricemia imposes various effects on sex hormones, semen quality, and male erectile dysfunction. Some researchers claim that uric acid worsens male semen and raises the risk of erectile dysfunction (ED), while others state that it safeguards both penile erection and male semen. Additionally, it has been shown that gout and metabolic syndrome also raise the risk of ED. To clarify this controversy, the influence and potential mechanisms of hyperuricemia on ED, semen quality, sex hormone levels, and the effects of hyperuricemia-related disorders on ED will be comprehensively summarized.

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 and its management in patients with diabetes mellitus

Diabetes can be described as a syndrome of multiple closely related conditions induced by a chronic state of hyperglycaemia resulting from defective insulin secretion, insulin action or both. Chronic complications associated with diabetes (including neuropathy, vascular disease, nephropathy and retinopathy) are common, and of these, erectile dysfunction (ED) deserves special attention. ED and its correlation with cardiovascular disease require careful evaluation and appropriate treatment. PDE5 inhibitors (PDE5is) are an important tool for the treatment of ED, with new drugs coming onto the market since the late 90s. This review offers an overview of PDE5is and their use in treating ED in diabetes. We underline the differences between different types of PDE5i, focusing on available doses, duration of action, T ½, side effects and selectivity profiles in relation to patients with diabetes. We also discuss the link between diabetes and ED in presence of various associated cofactors (obesity, hypertension and its pharmacological treatments, atherosclerosis, hyperhomocysteinaemia, neuropathy, nephropathy, hypogonadism and depression). Finally a number of past and ongoing clinical trials on the use of PDE5is in patients with diabetes are presented to offer an overview of the appropriate treatment of ED in this condition.

The effect of lifestyle modification and glycemic control on the efficiency of sildenafil citrate in patients with erectile dysfunction due to type-2 diabetes mellitus

OBJECTIVES

We evaluated the effect of lifestyle modifications and glycemic control on the efficiency of sildenafil citrate in patients with type-2 diabetes (T2DM) and erectile dysfunction (ED).

METHODS

Eighty-three men with ED due to T2DM were included in the study. The Group 1 (n = 41) patients received lifestyle modifications (diet and exercise), and medical treatment for intensive glycemic control. In Group 2 (n = 42), in addition to the intensive glycemic control, the patients were given sildenafil citrate® 100 mg for 2-3 per weeks. The changes in ED were compared between the two groups after three months of treatment.

RESULTS

The mean age was 54.9 ± 9.1 (26-75) years. An increase in the IIEF-5 scores was observed in 23 of 41 patients in Group 1 (44.2%) and 29 of 42 in Group 2 (55.8%). When the changes of the IIEF-5 scores were evaluated, the mean increase was 2.5 in Group 1, and 5.0 in Group 2 (p = 0.012). The mean IIEF changes according to the duration of diabetes were 4.8 in <5 years, 3.6 in 5-10 years and 1.6 in >10 years (p = 0.021).

CONCLUSIONS

Glycemic control and lifestyle changes are not solely adequate for a better sexual function in ED due to diabetes, and sildenafil citrate should be used additionally.

The impact of metabolic syndrome on serum total testosterone level in patients with erectile dysfunction

OBJECTIVES

To determine the association between metabolic syndrome (MetS) and serum testosterone levels (TT) in patients with erectile dysfunction (ED).

METHODS

This study included 280 ED patients above 40-years-of-age. Participants were divided into two groups according to 2005 criteria of International Diabetes Federation. The severity of ED was determined according to the International Index of Erectile Function-EF (IIEF-EF score; 0-10 severe ED, 11-25 mild to moderate ED). The severity of ED, serum TT levels and other MetS components were compared between the groups.

RESULTS

The mean age of the patients was 55.7 ± 8.2 years. One hundred eighteen patients (%42.1) had MetS. Sixty-eight patients with MetS (57.6%) and 71 patients without MetS (43.8%) had severe ED (p = 0.031). A total of 46 (16.4%) patients had hypogonadism. Hypogonadism was seen more prevalent in patients with MetS (22.9% vs. 11.7%, p = 0.013). Logistic regression analyses for ED risk factors demonstrated that abnormal FBG increased the relative risk of severe ED up to 10.7-fold (p < 0.001) but not presence of hypogonadism (p = 0.706).

CONCLUSION

Metabolic syndrome was seen in almost half of the patients with ED. ED was more severe among MetS patients. Hypogonadism alone is a not risk factor for severe ED.

The impact of metabolic syndrome on retinal findings in patients with erectile dysfunction

OBJECTIVE

In the present study, we investigated the association between metabolic syndrome (MS) and retinal findings in patients presenting with erectile dysfunction (ED) complaints.

MATERIAL AND METHODS

A total of 102 patients with ED were included in this study. The patients were divided into two groups according to the National Cholesterol Education Program Adult Treatment Panel - III consensus definition: patients with MS (Group 1, n=62) and patients without MS (Group 2, n=40). The severity of ED was determined according to the first five versions of the International Index of Erectile Function. A detailed fundus examination was performed to evaluate the patients for retinopathy. The patients' retinopathy grades were classified according to the Early Treatment Diabetic Retinopathy Study.

RESULTS

The mean age of the patients was 51.4 years. Twenty-two patients (35.5%) in Group 1 and nine (22.5%) in Group 2 had severe ED (p=0.241). Ten (16.1%) patients in Group 1 and one (2.5%) patient in Group 2 had any degree of retinopathy (p=0.047). The logistic regression analysis of the correlation between severe ED and MS risk factors revealed that a fasting glucose level (FBG) of >110 mg/dL increased the risk of severe ED by 2.5 times (95% CI 1-6.2, p=0.058). Additionally, the logistic regression analysis of metabolic risk factors showed that only the FBS level was strongly associated with retinopathy, with the relative risk increased to 10.6 (95% CI 1.2-93, p=0.033).

CONCLUSION

Our results showed that elevated FBG levels were the most critical MS component in the development of severe ED and retinopathy.

Increased phosphodiesterase type 5 levels in a mouse model of type 2 diabetes mellitus

INTRODUCTION

Diabetes mellitus (DM) is a major risk factor for developing erectile dysfunction (ED) and men with DM are often less responsive to phosphodiesterase type 5 (PDE5) inhibitors than ED due to other causes.

AIMS

The aim of this study was to explore potential mechanisms whereby PDE5 inhibitors may have reduced efficacy in type 2 DM.

METHODS

At 4 weeks of age, mice were either fed a high-fat diet (HFD) for 22-36 weeks or fed regular chow (control). An additional group of mice in the same genetic background had a genetic form of type 1 DM.

MAIN OUTCOME MEASURES

Glucose tolerance testing, intracorporal pressures (ICPs), oxidative stress (OS), apoptotic cell death (active caspase-3 and apostain), PDE5, p53, and cyclic guanosine monophosphate (cGMP) levels, and histological examination of inflow arteries were performed in mice fed a HFD and control mice. A group of mice with type 1 DM were studied for PDE5 expression levels.

RESULTS

All mice fed a HFD had impaired glucose tolerance compared with the age-matched mice fed on standard chow diet (control). HFD fed mice had reduced maximum ICPs following in vivo cavernous nerve electrical stimulation and increased apoptotic cell death, OS, and p53 levels in the corporal tissue. Interestingly, PDE5 levels were increased and cGMP levels were decreased. In contrast, mice with type 1 DM did not have increases in PDE5.

CONCLUSIONS

Taken together, our results suggest that type 2 DM-induced ED is associated with findings that could lead to reduced cGMP and may account for reduced efficacy of PDE5 inhibitors.

Erectile dysfunction and diabetes: a review of the current evidence-based medicine and a synthesis of the main available therapies

AIM

This review aimed to provide an update of the epidemiology, pathophysiology and management of erectile dysfunction (ED) in diabetes patients.

METHODS

Data on the management of ED in diabetes patients in the literature were analyzed using Medline, and by matching the following keywords: diabetes; erectile dysfunction; endothelial dysfunction; cardiovascular disease; phosphodiesterase inhibitors; intracavernous injection; and penile prosthesis.

RESULTS

ED has a higher incidence in diabetic patients. The pathophysiology is multifactorial, involving endothelial dysfunction, specific complications of diabetes and psychological factors. Recent studies have shown that ED is able to predict future cardiovascular events not only in non-diabetics, but also in patients with diabetes. ED could also be a potential marker to screen for silent coronary artery disease. The management of ED has been revolutionized by the discovery of phosphodiesterase type-5 (PDE5) inhibitors, the first-line therapeutic options for diabetic men with ED that are efficient and safe. As a second line, intracavernous injections remain a gold-standard treatment, although a vacuum device can be used as well. In cases of failure, penile prosthesis may be considered. Hypogonadism, commonly found in diabetics, may require identification and treatment. Optimalized glycaemic control, management of associated co-morbidities and lifestyle modifications are essential in all patients. As ED and diabetes negatively impact male self-esteem, and generate depression and anxiety, the psychological treatment of patients is also likely to be beneficial.

CONCLUSION

The aetiology of diabetic ED is multifactorial. Endothelial dysfunction is the link between diabetes-induced ED and coronary artery disease. A global approach is needed for the successful management of diabetic ED.

Urological aspects of the metabolic syndrome

The metabolic syndrome is common in countries with Western lifestyles. It comprises a number of disorders-including insulin resistance, hypertension and obesity-that all act as risk factors for cardiovascular diseases. Urological diseases have also been linked to the metabolic syndrome. Most established aspects of the metabolic syndrome are linked to benign prostatic hyperplasia (BPH) and prostate cancer. Fasting plasma insulin, in particular, has been linked to BPH and incident, aggressive and lethal prostate cancer. The metabolic syndrome has also been shown to be associated with nonprostatic urological conditions such as male hypogonadism, nephrolithiasis, overactive bladder and erectile dysfunction, although data on these conditions are still sparse. Overall, the results of studies on urological aspects of the metabolic syndrome seem to indicate that BPH and prostate cancer could be regarded as two new aspects of the metabolic syndrome, and that an increased insulin level is a common underlying aberration that promotes both BPH and clinical prostate cancer. Urologists need to be aware of the effect that the metabolic syndrome has on urological disorders and should transfer this knowledge to their patients.