Weight loss more than glycemic control may improve testosterone in obese type 2 diabetes mellitus men with hypogonadism

Pharmacotherapeutic strategies for the management of erectile dysfunction in patients with diabetes and pre-diabetes

INTRODUCTION

Erectile dysfunction (ED) is a neglected complication in patients with pre-diabetes or diabetes mellitus (DM).

AREAS COVERED

A summary and review of the role of standard ED treatment and the contribution of lifestyle modification and hypoglycemic drugs.

EXPERT OPINION

Oral phosphodiesterase type 5 inhibitors (PDE5i) represent the first-line therapy even in patients with DM. Testosterone replacement therapy (TRT) is mandatory in all hypogonadal (total testosterone < 12 nmol/l) subjects. Alprostadil and/or combined approaches can be considered when PED5i with or without TRT fail. The glycometabolic optimization through lifestyle modification and the use of hypoglycemic drugs represents a crucial step, even for ED treatment. Considering the strong association between ED and forthcoming cardiovascular diseases, the selection of glucagon-like peptide type 1 analogues or sodium glucose cotransporter-2 inhibitors seems to represent the best option due to their long-term effect on chronic complication prevention. Metformin can be considered a possible alternative in less complicated subjects. Penile prostheses (PP) can be offered when all other options are not effective, but the patients should be informed that poor glycometabolic control can increase the risk of PP infection.

Hypogonadism and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD), recently proposed to be renamed to metabolic dysfunction-associated steatotic liver disease (MASLD), is a major global public health concern, affecting approximately 25-30% of the adult population and possibly leading to cirrhosis, hepatocellular carcinoma, and liver transplantation. The liver is involved in the actions of sex steroids via their hepatic metabolism and production of the sex hormone-binding globulin (SHBG). Liver disease, including NAFLD, is associated with reproductive dysfunction in men and women, and the prevalence of NAFLD in patients with hypogonadism is considerable. A wide spectrum of possible pathophysiological mechanisms linking NAFLD and male/female hypogonadism has been investigated. As therapies targeting NAFLD may impact hypogonadism in men and women, and vice versa, treatments of the latter may affect NAFLD, and an insight into their pathophysiological pathways is imperative. This paper aims to elucidate the complex association between NAFLD and hypogonadism in men and women and discuss the therapeutic options and their impact on both conditions.

Effects of the glucagon-like peptide-1 receptor agonist dulaglutide on sexuality in healthy men: a randomised, double-blind, placebo-controlled crossover study

BACKGROUND

The reward-regulatory properties of GLP-1 are attracting increasing interest. Animal studies show that GLP-1 receptor agonists not only reduce consumption of addictive substances, but also influence sexual behaviour. We aimed to investigate the effect of dulaglutide versus placebo on sexual desire in humans.

METHODS

In this randomised, double-blind, placebo-controlled crossover trial, healthy eugonadal men of normal weight, aged 18-50 years with active and satisfactory sex lifes were (1:1) randomly allocated to dulaglutide or placebo for four weeks. We assessed sexual desire (Massachusetts General Hospital-Sexual Functioning Questionnaire [MGH-SFQ]), hormones of the hypothalamic-pituitary-gonadal axis (total testosterone, follicle-stimulating hormone [FSH], luteinizing hormone [LH]) and sperm parameters. Changes in these parameters were compared under dulaglutide versus placebo using paired t-tests.

FINDINGS

24 out of 26 randomised participants completed the study (13 participants randomised to dulaglutide first and 13 to placebo first). No change in the MGH-SFQ was observed after four weeks of dulaglutide versus placebo (estimated difference 0.58 [95% CI -0.83 to 2.00], p-value = 0.402). Hormones of the hypothalamic-pituitary-gonadal axis (estimated differences: total testosterone (nmol/l) 0.9 [95% CI -1.5 to 3.3], FSH (IU/l) -0.2 [95% CI -0.3 to 0.0] and LH (IU/l) -0.8 [95% CI -1.5 to 0.0]) as well as sperm parameters all remained in the normal range without significant differences between the treatments. No severe adverse events occurred.

INTERPRETATION

In this study of healthy men, we found no evidence of negative impacts of a four-week treatment with the widely used GLP-1 receptor agonist dulaglutide on sexual desire, hypothalamic-pituitary-gonadal axis hormones or sperm parameters.

FUNDING

Swiss National Science Foundation (PZ00P3_193206), Gottfried and Julia Bangerter-Rhyner Foundation, Goldschmidt-Jacobson Foundation, Swiss Academy of Medical Sciences.

Pharmacological management of testosterone deficiency in men current advances and future directions

INTRODUCTION

Testosterone deficiency (TD) is relatively common in aging men, affecting around 2% of the general population. Testosterone replacement therapy (TRT) represents the most common medical approach for subjects who are not interested in fathering.

AREAS COVERED

This review summarizes advances in TRT, including approved or non-approved pharmacological options to overcome TD. When possible, a meta-analytic approach was applied to minimize subjective and biased interpretations of the available data.

EXPERT OPINION

During the last decade, several new TRT formulations have been introduced on the market, including oral, transdermal, and parenteral formulations. Possible advantages and limitations have been discussed appropriately. Anti-estrogens, including selective estrogen modulators or aromatase inhibitors still represent further possible off-label options. However, long-term side effects on sexual function and bone parameters constitute major limitations. Glucagon-like peptide 1 analogues can be an alternative option in particular for massive obesity-associated TD. Weight loss obtained through lifestyle modifications including diet and physical exercise should be encouraged in all overweight and obese patients. A combination of TRT and lifestyle changes can be considered in those subjects in whom a reversal of the condition cannot be expected in a reasonable time frame.

Effects of empagliflozin on reproductive system in men without diabetes

Sodium-glucose cotransporter (SGLT) 2 inhibition is a well-known target for the treatment of type 2 diabetes, renal disease and chronic heart failure. The protein SGLT2 is encoded by SLC5A2 (Solute Carrier Family 5 Member 2), which is highly expressed in renal cortex, but also in the testes where glucose uptake may be essential for spermatogenesis and androgen synthesis. We postulated that in healthy males, SGLT2 inhibitor therapy may affect gonadal function. We examined the impact on gonadal and steroid hormones in a post-hoc analysis of a double-blind, randomized, placebo-controlled research including 26 healthy males who were given either placebo or empagliflozin 10 mg once daily for four weeks. After one month of empagliflozin, there were no discernible changes in androgen, pituitary gonadotropin hormones, or inhibin B. Regardless of BMI category, the administration of empagliflozin, a highly selective SGLT2 inhibitor, did not alter serum androgen levels in men without diabetes. While SGLT2 is present in the testes, its inhibition does not seem to affect testosterone production in Leydig cells nor inhibin B secretion by the Sertoli cells.

Advances in the treatment of functional male hypogonadism

INTRODUCTION

Functional hypogonadism is frequently found in obese men, particularly those with metabolic complications. Several possible therapeutic approaches could be considered.

AREAS COVERED

An extensive search on Medline, Embase, and Cochrane databases was performed to retrieve the available studies assessing the change of testosterone (T) and sexual function upon dieting or physical activity programs, as well as glucagon-like peptide 1 analogues. The role of lifestyle interventions associated with T replacement therapy (TRT) was also evaluated. The expert opinion provided here has been corroborated by meta-analyzing the results of the retrieved studies.

EXPERT OPINION

Current evidence supports the beneficial role of lifestyle modifications in increasing T and improving sexual function as a function of weight loss. While dieting programs are associated with greater effects in younger populations, physical exercise has major effects in older ones. Among the dieting programs, a very low-calorie ketogenic diet shows the best results; aerobic or endurance physical exercise perform similarly. The advantages of functional hypogonadism in lifestyle modifications are empowered by the association with TRT. Therefore, TRT may be a valuable complementary strategy to increase muscle mass and facilitate physical exercise while improving sexual symptoms, thus favoring the motivation and compliance for lifestyle interventions.

Long-acting glucagon-like peptide 1 receptor agonists boost erectile function in men with type 2 diabetes mellitus complaining of erectile dysfunction: A retrospective cohort study

INTRODUCTION

The pharmacological management of erectile dysfunction (ED) in type 2 diabetes (T2D) is challenging as ED has a multifactorial etiology. The therapeutic potential of certain antihyperglycemic medications, such as glucagon-like peptide 1 receptor agonists (GLP-1RAs), has yet to be entirely studied in this setting.

MATERIAL AND METHODS

A retrospective cohort study was conducted on 108 outpatients (median age 60 [56, 65] years) with T2D complaining of ED. Data were extracted from a database referring to patients with a 1-year follow-up on stable treatment with metformin alone (n = 45) and GLP-1RAs as an add-on to metformin (n = 63). Erectile function was assessed by the 5-item International Index of Erectile Function (IIEF5) at baseline and after 1 year of stable treatment . Values were compared between baseline (T0) and after 12 months of treatment (T12).

RESULTS

ED was confirmed in all at baseline, with an IIEF5 score range between 13 and 19 points. After 12 months of treatment, glucose management was better in patients treated with GLP-1RAs plus metformin (HbA1c T0: 8.3 ± 0.2 vs. HbA1c T12: 7% ± 0.3%, p < 0.0001) than in those on metformin alone (HbA1c T0: 7 ± 0.5 vs. HbA1c T12: 7.3 ± 0.4, p = 0.0007). GLP-1RAs plus metformin over metformin alone resulted in a significant weight loss (-5.82 ± 0.69 kg, p < 0.0001), reduction in waist circumference (-4.99 ± 0.6 cm, p < 0.0001), improvement in HbA1c (-0.56% ± 0.13%, p < 0.0001), and fasting plasma glucose (-25.54 ± 3.09 mg/dL, p < 0.0001), increase in total (+41.41 ± 6.11 ng/dL, p < 0.0001) and free (0.44 ± 0.09 ng/dL, p < 0.0001) testosterone levels, and gain in self-reported erectile function (IIEF5 score: +2.26 ± 0.26, p < 0.0001). The gain in the IIEF5 score was more relevant in patients with higher baseline IIEF5 score (estimated coefficient: 0.16 ± 0.08, p = 0.045), those having carotid stenosis (0.50 ± 0.24, p = 0.045), and showing weight loss from baseline (-0.08 ± 0.03, p = 0.013). The leading determinant of the final IIEF5 score was a 1-year treatment with GLP-1RAs plus metformin over metformin alone (2.74 ± 0.53, p < 0.0001).

DISCUSSION

GLP-1RAs plus metformin over metformin alone improved ED regardless of different background characteristics of patients and partially irrespective of therapeutic targets achieved after 12 months of treatment. GLP-1RAs may have induced positive vasculature effects, resulting in improved erectile function in T2D.

CONCLUSION

Due to the retrospective nature of the study, a potential cause-effect relationship between the use of GLP-1RAs plus metformin over metformin alone in improving ED cannot be verified and confirmed. Randomized clinical trials are needed to provide evidence supporting the use of GLP-1RAs for treating ED in T2D.

Non-medical and non-invasive interventions for erectile dysfunction in men with type 2 diabetes mellitus: A scoping review

Background

Erectile dysfunction (ED) often affects men with type 2 diabetes mellitus (T2DM) due to microvascular damage. However, medical interventions are not always appropriate.

Aim

This scoping review aimed to answer the following question: What evidence is available about the effects of non-medical and non-invasive healthcare interventions to improve ED in men with T2DM?

Method

Potential studies were collected from the Cumulative Index to Nursing and Allied Health Literature via EBSCO, Embase via Ovid, MEDLINE via Ovid, Web of Science, PubMed, ProQuest, and PsycINFO via Ovid.

Findings

From 2,611 identified titles, 17 studies, including 11 interventional and 6 observational studies, were included. Four main alternatives to medical interventions were identified from the included studies. Amongst these, four studies recommended patient education on lifestyle modification, twelve studies encouraged dietary changes and physical activities, two studies emphasized the use of vacuum erectile device, and three studies suggested the application of low-intensity extracorporeal shockwave therapy by healthcare professionals.

Discussion

Dietary modification and physical activities were promoted as effective interventions to help maintaining the erectile function in men with T2DM. Several methods of patient education were identified as the approach to facilitate lifestyle modification in men with T2DM-associated ED. The positive outcomes of this review support early ED screening to help preventing T2DM complications such as ED in men. Further, T2DM management is a shared responsibility between the men and healthcare professionals. Despite the success of Vacuum Erectile Device and Low-intensity Extracorporeal Shockwave Therapy in regaining erectile function, further research is needed in this area based on the recommendations of the American Urological Association. Moreover, the health and quality of life of men with T2DM must be improved.

The role of male hypogonadism, aging, and chronic diseases in characterizing adult and elderly men with erectile dysfunction: a cross-sectional study

BACKGROUND

Erectile function depends on a complex interaction between demographic, metabolic, vascular, hormonal, and psychological factors that trigger erectile dysfunction (ED). In the present study we carried out a cross-sectional study assessing the impact of non-communicable chronic diseases (NCDs), male hypogonadism, and demographic factors in characterizing men with ED. Four hundred thirty-three consecutive outpatients with ED were extracted from the electronic database from January 2017 to December 2019. The International Index of Erectile Function (IIEF) 5 score was used to diagnose ED and stratify its severity, standardized values of serum testosterone (10.5 nM/L) and luteinizing hormone (LH 9.4 IU/L) to diagnose and classify male hypogonadism and the Charlson Comorbidity Index (CCI) to weigh the role of each NCD on ED.

RESULTS

Forty-six percent of participants were eugonadal (EuG), 13% had organic hypogonadism (OrH), and the remaining 41% had functional hypogonadism (FuH). Hypogonadal men had a significantly lower IIEF 5 score (p < .0001) than EuG. FuH had a higher CCI than OrH and EuG (all p < .0001). In a multivariable model, only free T (FT) and Sex Hormone Binding Globulin (SHBG) showed a direct correlation with the IIEF 5 score (all p < .0001). Age and CCI had an inverse correlation with IIEF 5 score (all p < .0001).

CONCLUSION

Serum FT, SHBG, and CCI are the leading determinants of ED severity. Besides overt hypogonadism, a relevant burden of severe NTCDs in middle-aged or older adults features the patient's characteristics who will suffer from severe ED. Appropriate clinical approaches and, when necessary, treatments are required in these clusters of patients.

Ketogenic state improves testosterone serum levels-results from a systematic review and meta-analysis

BACKGROUND

It is widely demonstrated that obesity and hypogonadism are bi-directionally correlated, since the hypogonadism prevalence is higher in obese population, while weight loss increases testosterone serum levels. Several approaches are available to contrast weight excess, from simple dietary regimens to more complex surgical procedures. Ketogenic diets (KD) fit in this context and their application is growing year after year, aiming to improve the metabolic and weight patterns in obese patients. However, KD influence on testosterone levels is still poorly investigated.

OBJECTIVES

To systematically evaluate the potential effect of KD on testosterone levels.

METHODS

A systematic literature search was performed until April 2022 including studies investigating testosterone levels before and after KD. Secondary endpoints were body weight, estradiol and sex-hormone binding globulin serum levels. Any kind of KD was considered eligible, and no specific criteria for study populations were provided.

RESULTS

Seven studies (including eight trials) were included in the analysis for a total of 230 patients, five using normocaloric KD and three very low calories KD (VLCKD). Only three studies enrolled overweight/obese men. A significant total testosterone increase was recorded after any kind of KD considering 111 patients (2.86 [0.95, 4.77], p = 0.003). This increase was more evident considering VLCKD compared to normocaloric KD (6.75 [3.31, 10.20], p < 0.001, versus 0.98 [0.08, 1.88], p = 0.030). Meta-regression analyses highlighted significant correlations between the post-KD testosterone raise with patients' age (R-squared 36.4, p < 0.001) and weight loss (R-squared 73.6, p < 0.001).

CONCLUSIONS

Comprehensively, KD improved testosterone levels depending on both patients' age and KD-induced weight loss. However, the lack of information in included studies on hormones of the hypothalamic-pituitary-gonadal axis prevents an exhaustive comprehension about mechanisms connecting ketosis and testosterone homeostasis.

Effects of treatment for diabetes mellitus on testosterone concentrations: A systematic review

BACKGROUND

Low testosterone levels are frequently present in men with obesity and insulin resistance. Currently available treatment options (testosterone replacement therapy or lifestyle changes) hold possible risks or are insufficient. Since low testosterone levels are closely related to obesity and type 2 diabetes, treatment modalities for these conditions could result into improvement of testosterone levels.

OBJECTIVES

To summarize the available evidence on the effects of traditional and recent treatment modalities for diabetes mellitus on testosterone levels and androgen-deficiency-related signs and symptoms.

MATERIALS AND METHODS

PubMed was searched from the year 2000 till present using MESH terms: "hypogonadism," "testosterone," "testosterone deficiency," "functional hypogonadism," and the different classes of medications. Studies with observational and experimental designs on humans that evaluated the effect of antidiabetic medications on gonadotropins and testosterone were eligible for inclusion.

RESULTS

Current available data show no or only limited improvement on testosterone levels with the classic antidiabetic drugs. Studies with GLP1-receptor analogues show beneficial effects on both body weight and testosterone levels in men with low testosterone levels and obesity with or without type 2 diabetes. However, data are limited to small and heterogeneous study groups and only few studies report data about impact on androgen-deficiency-related signs and symptoms.

DISCUSSION AND CONCLUSION

With the recent advances in the knowledge of the pathophysiological pathways in obesity, there is an enormous progress in the development of medications for obesity and type 2 diabetes. Newer incretin-based agents have a great potential for the treatment of functional hypogonadism due to obesity since they show promising weight reducing results. However, before the use of GLP1-receptor analogues can be suggested to treat functional hypogonadism, further studies are needed.

Obesity, type 2 diabetes, and testosterone in ageing men

In the absence of obesity, adverse lifestyle behaviours, and use of medication such as opioids serum testosterone concentrations decrease by only a minimal amount at least until very advanced age in most men. Obesity is heterogeneous in its phenotype, and it is the accumulation of excess adipose tissue viscerally associated with insulin resistance, dyslipidaemia, inflammation, hypothalamic leptin resistance and gliosis that underpins the functional hypogonadism of obesity. Both central (hypothalamic) and peripheral mechanisms are involved resulting in a low serum total testosterone concentration, while LH and FSH are typically in the normal range. Peripherally a decrease in serum sex hormone binding globulin (SHBG) concentration only partially explains the decrease in testosterone and there is increasing evidence for direct effects in the testis. Men with obesity associated functional hypogonadism and serum testosterone concentrations below 16 nmol/L are at increased risk of incident type 2 diabetes (T2D); high testosterone concentrations are protective. The magnitude of weight loss is linearly associated with an increase in serum testosterone concentration and with the likelihood of preventing T2D or reverting newly diagnosed disease; treatment with testosterone for 2 years increases the probability of a positive outcome from a lifestyle intervention alone by approximately 40%. Whether the additional favourable benefits of testosterone treatment on muscle mass and strength and bone density and quality in the long-term remains to be determined.

Safety of androgen therapy in men with prostate cancer

Prostate cancer is one of the most frequently diagnosed malignancies in men worldwide and the life expectancy for men with prostate cancer is improving due to advancements in diagnostics and treatment. Male hypogonadism is associated with obesity, diabetes, and other comorbidities and also has been linked with increasing age; the primary therapy modality for this condition is testosterone replacement therapy (TRT). There are concerns that testosterone therapy may cause prostate cancer disease progression. However, contemporary evidence suggests that testosterone replacement therapy may be safe in specific groups of patients with prostate cancer. This chapter will summarise the contemporary literature regarding TRT use in hypogonadal men with prostate cancer, including limitations and future research goals.

High-Amylose Corn Starch Regulated Gut Microbiota and Serum Bile Acids in High-Fat Diet-Induced Obese Mice

Simple Summary

High-amylose corn starch, as a kind of resistant starch, could profoundly regulate the gut microbiota and exert anti-obesity properties. Since the gut microbiota was found to improve metabolic health by altering circulating bile acids, therefore, here we investigated the association between the gut microbiota and serum bile acids in high fat diet induced obese mice fed with high-amylose corn starch. We found high-amylose corn starch could modulate the gut microbiota composition and partially restore the alternations in circulating bile acid profiles in obese mice. These influences on gut microbiota and circulating bile acids could be the underlying mechanisms of anti-obesity activity of high-amylose corn starch.

Abstract

High-amylose corn starch is well known for its anti-obesity activity, which is mainly based on the regulatory effects on gut microbiota. Recently, the gut microbiota has been reported to improve metabolic health by altering circulating bile acids. Therefore, in this study, the influence of high-amylose corn starch (HACS) on intestinal microbiota composition and serum bile acids was explored in mice fed with a high fat diet (HFD). The results demonstrated HACS treatment reduced HFD-induced body weight gain, hepatic lipid accumulation, and adipocyte hypertrophy as well as improved blood lipid profiles. Moreover, HACS also greatly impacted the gut microbiota with increased Firmicutes and decreased Bacteroidetes relative abundance being observed. Furthermore, compared to ND-fed mice, the mice with HFD feeding exhibited more obvious changes in serum bile acids profiles than the HFD-fed mice with the HACS intervention, showing HACS might restore HFD-induced alterations to bile acid composition in blood. In summary, our results suggested that the underlying mechanisms of anti-obesity activity of HACS may involve its regulatory effects on gut microbiota and circulating bile acids.

Overall sexual function in dysmetabolic obese men with low testosterone levels treated with clomiphene citrate

BACKGROUND

Sexual disorders are the most common clinical manifestations of hypogonadism. Functional hypogonadism is the most frequent form, and clomiphene citrate (CC) has been recently introduced as a possible off-label therapeutic option for these patients.

OBJECTIVES

This study aims to evaluate the effects of CC on the overall sexual function in dysmetabolic obese men with low testosterone(T) levels.

METHODS

This was a sub-study of a randomized, double-blind, cross-over, placebo-controlled trial that included twenty-four obese or overweight subjects, with impaired glucose tolerance, or type 2 diabetes, and confirmed low total T (≤10.4 nmol/l) levels. Subjects were treated with CC or placebo (Plac) for 12 weeks, with an interval wash-out period of 6 weeks between treatments. All subjects were on metformin 2gr/day and a low-calorie diet. The between-treatment difference in the overall sexual function was assessed by IIEF-15 and a qADAM questionnaire.

RESULTS

IIEF-15 and qADAM questionnaire data were available for 18 individuals. In unadjusted analyses, CC was associated with lower IIEF-15 total, erectile function, and intercourse satisfaction domain scores than Plac. After adjustments for multiple variables, CC was associated with a higher IIEF-15 sexual desire domain score (+0.9 ± 0.8; p<.001) despite a lower qADAM score (-2.1 ± 0.9; p=.008) with respect to Plac. No differences were found for the other domains between groups.

DISCUSSION

The clinical significance of the absolute changes in IIEF-15 and qADAM scores during CC versus Plac is limited. However, CC has a reliable effect on sexual desire, and is also as safe as Plac. According to the sample size, duration of follow-up, and inclusion criteria defined for the main study, further studies are therefore needed to assess the long-term efficacy of CC.

CONCLUSION

Compared to Plac, CC was associated with a neutral effect on overall sexual function.

Endocrine system dysfunction and chronic heart failure: a clinical perspective

Chronic heart failure (CHF) leads to an excess of urgent ambulatory visits, recurrent hospital admissions, morbidity, and mortality regardless of medical and non-medical management of the disease. This excess of risk may be attributable, at least in part, to comorbid conditions influencing the development and progression of CHF. In this perspective, the authors examined and described the most common endocrine disorders observed in patients with CHF, particularly in individuals with reduced ejection fraction, aiming to qualify the risks, quantify the epidemiological burden and discuss about the potential role of endocrine treatment. Thyroid dysfunction is commonly observed in patients with CHF, and sometimes it could be the consequence of certain medications (e.g., amiodarone). Male and female hypogonadism may also coexist in this clinical context, contributing to deteriorating the prognosis of these patients. Furthermore, growth hormone deficiency may affect the development of adult myocardium and predispose to CHF. Limited recommendation suggests to screen endocrine disorders in CHF patients, but it could be interesting to evaluate possible endocrine dysfunction in this setting, especially when a high suspicion coexists. Data referring to long-term safety and effectiveness of endocrine treatments in patients with CHF are limited, and their impact on several "hard" endpoints (such as hospital admission, all-cause, and cardiovascular mortality) are still poorly understood.

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.

The Effects of the New Therapeutic Treatments for Diabetes Mellitus on the Male Reproductive Axis

One of the complications of chronic hyperglycemia and insulin resistance due to type 2 diabetes mellitus (T2DM) on the hypothalamic-pituitary-gonadal axis in men, is the high prevalence of hypogonadotropic hypogonadism, which has been recently defined as functional hypogonadism, characterized by low testosterone associated with inappropriately normal gonadotropin levels. Although the pathophysiology of this hormonal imbalance may be related to several factors, including glycemic control, concomitant sleep apnea, insulin resistance, the main role is determined by the degree of central or visceral obesity and the consequent inflammatory state. Several drugs have been developed to treat T2DM such as glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase 4 inhibitors, and sodium-glucose co-transporter 2 inhibitors. All appear to be effective in ameliorating blood glucose control, by lowering inflammation and body weight, and most seem to reduce the risk of micro- and macrovascular damage as a consequence of uncontrolled diabetes. A few studies have evaluated the impact of these drugs on gonadal function in T2DM patients with hypogonadism, with promising results. This review summarizes the main current knowledge of the effects of these new antidiabetic drugs on the hypothalamus-pituitary-gonadal axis, showing their potential future application in addition to glucose control in dysmetabolic male patients.

Short-time intensive insulin therapy upregulates 3 beta- and 17 beta-hydroxysteroid dehydrogenase levels in men with newly diagnosed T2DM

OBJECTIVE

Our previous study has found that short-term intensive insulin therapy in patients with newly diagnosed type 2 diabetes mellitus (T2DM) increased serum testosterone levels, but the underlying mechanisms remain unclear.

DESIGN AND METHODS

In this self-controlled study, 43 men with newly diagnosed drug naïve T2DM, aged 18-60 years, with HbA_{1c >}9.0% were treated with continuous subcutaneous insulin infusion (CSII) to normalize blood glucose within one week. Venous blood specimens were collected for measuring of serum total testosterone, dehydroepiandrosterone sulfate (DHEA-S), 3β- and 17β-hydroxysteroid dehydrogenase (3β- and 17β-HSD) concentrations before and after insulin therapy.

RESULTS

Testosterone increased from 13.0 (11.3, 14.6) nmol/L to 15.7 (13.9, 17.5) nmol/L after intensive insulin therapy (p<0.001), while the levels of DHEA-S decreased significantly after treatment (from 6.5 (5.7, 7.3) μmol/L to 6.0 (5.3, 6.7) μmol/L, p=0.001). The ratio of testosterone/DHEA-S increased significantly (2.4 (2.0, 2.8) vs. 3.1 (2.6, 3.7) nmol/μmol, p<0.001). After blood glucose normalization with the short-term CSII therapy, 3β-HSD increased from 11.0 (9.5, 12.5) pg/mL to 14.6 (13.5, 15.7) pg/mL, p=0.001, and 17β-HSD increased from 20.7 (16.3, 25.2) pg/mL to 28.2 (23.8, 32.5) pg/mL, p=0.009.

CONCLUSIONS

Blood glucose normalization via short-term intensive insulin therapy increases plasma total testosterone levels in men with newly diagnosed type 2 diabetes, associated with a decreased level of DHEA-S, probably because of the enhanced conversion from DHEA to testosterone catalyzed by 3β-HSD and 17β-HSD.

Testosterone therapy for prevention and reversal of type 2 diabetes in men with low testosterone

Men with obesity and/or type 2 diabetes (T2D) have a high prevalence of testosterone deficiency (TD). Similarly, men with TD have an increased risk of developing obesity and/or T2D, and further body fat accumulation and deterioration of glycemic control create a vicious cycle. The landmark testosterone for diabetes mellitus trial, the largest randomized controlled trial of testosterone therapy (TTh) to date, confirms the beneficial effects of TTh on fat loss and gain in muscle mass, and that TTh for 2 years significantly reduces the risk of incident T2D, and may also reverse T2D. The testosterone for diabetes mellitus trial suggests that TTh reduces the risk of T2D and results in greater improvement in sexual function and wellbeing, beyond lifestyle intervention alone.

The ketogenic diet corrects metabolic hypogonadism and preserves pancreatic ß-cell function in overweight/obese men: a single-arm uncontrolled study

BACKGROUND

Overweight and obesity are increasingly spread in our society. Low testosterone levels are often present in these patients, the so-called metabolic hypogonadism, that further alters the metabolic balance in a sort of vicious cycle. Very low-calorie ketogenic diet (VLCKD) has been reported to efficiently reduce body weight, glycaemia, and the serum levels of insulin, glycated hemoglobin, but its effects on β-cell function and total testosterone (TT) levels are less clear.

AIM

To evaluate the effects of VLCKD on markers suggested to be predictive of β-cell dysfunction development, such as proinsulin or proinsulin/insulin ratio, and on TT values in a cohort of overweight or obese nondiabetic male patients with metabolic hypogonadism.

METHODS

Patients with overweight or obesity and metabolic hypogonadism underwent to VLCKD for 12 weeks. Anthropometric parameters, blood testing for the measurement of glycaemia, insulin, C-peptide, proinsulin, TT, calculation of body-mass index (BMI), and HOMA index were performed before VLCKD and after 12 weeks.

RESULTS

Twenty patients (mean age 49.3 ± 5.2 years) were enrolled. At enrollement all patients presented increased insulin, HOMA index, C-peptide, and proinsulin levels, whereas the proinsulin/insulin ratio was within the normal values. After VLCKD treatment, body weight and BMI significantly decreased, and 14.9 ± 3.9% loss of the initial body weight was achieved. Glycaemia, insulin, HOMA index, C-peptide, and proinsulin significantly decreased compared to pre-VLCKD levels. Serum glycaemia, insulin, C-peptide, and proinsulin levels returned within the normal range in all patients. No difference in the proinsulin/insulin ratio was observed after VLCKD treatment. A mean increase of 218.1 ± 53.9% in serum TT levels was achieved and none of the patients showed TT values falling in the hypogonadal range at the end of the VLCKD treatment.

CONCLUSIONS

This is the first study that evaluated the effects of VLCKD on proinsulin, proinsulin/insulin ratio, and TT levels. VLCKD could be safely used to improve β-cell secretory function and insulin-sensitivity, and to rescue overweight and obese patients from β-cell failure and metabolic hypogonadism.

Glycemic benefits with adherence to testosterone therapy in men with hypogonadism and type 2 diabetes mellitus

BACKGROUND

While previous studies have demonstrated testosterone's beneficial effects on glycemic control in men with hypogonadism and Type 2 Diabetes, the extent to which these improvements are observed based on the degree of treatment adherence has been unclear.

OBJECTIVES

To evaluate the effects of long-term testosterone therapy in A1C levels in men with Type 2 Diabetes Mellitus and hypogonadism, controlling for BMI, pre-treatment A1C, and age among different testosterone therapy adherence groups.

MATERIALS AND METHODS

We performed a retrospective analysis of 1737 men with diabetes and hypogonadism on testosterone therapy for 5 years of data from 2008-2018, isolating A1C, lipid panels, and BMI results for analysis. Subjects were categorized into adherence groups based on quartiles of the proportion of days covered (> 75% of days, 51-75% of days, 26-50% of days and 0-25% of days), with >75% of days covered considered adherent to therapy.

RESULTS

Pre-treatment median A1C was 6.8%. Post-treatment median A1C was 7.1%. The adherent group, >75%, was the only group notable for a decrease in A1C, with a median decrease of -0.2 (p = 0.0022). BMI improvement was associated with improved post-treatment A1C (p = 0.007). When controlling for BMI, age, and pre-treatment A1C, the >75% adherence group was associated with improved post-treatment A1C (p < 0.001).

DISCUSSION

When controlling for all studied variables, testosterone adherence was associated with improved post-treatment A1C. The higher the initial A1C at the initiation of therapy, the higher the potential for lowering the patient's A1C with >75% adherence. Further, all groups showed some reduction in BMI, which may indicate that testosterone therapy may affect A1C independent of weight loss.

CONCLUSION

Even when controlling for improved BMI, pre-treatment A1C, and age, testosterone positively impacted glycemic control in diabetes patients with hypogonadism, with the most benefit noted in those most adherent to therapy (>75%).

Age-Related Male Hypogonadism and Cognitive Impairment in the Elderly: Focus on the Effects of Testosterone Replacement Therapy on Cognition

BACKGROUND

Epidemiological data report that male hypogonadism may play a role in cognitive impairment in elderly. However, the effect of testosterone replacement therapy (TRT) on cognitive abilities in this cluster of patients has not been well established. Methods. PubMed/MEDLINE, Google Scholar, Cochrane Library, and Web of Science were searched by using free text words and medical subject headings terms related with "male hypogonadism", "late-onset hypogonadism", elderly, cognition, "mild cognitive impairment", memory, "testosterone replacement therapy" used in various combinations according to the specific clinical questions. Original articles, reviews, and randomized controlled trials written in English were selected. Results. A long-term TRT could improve specific cognitive functions, such as verbal and spatial memory, cognitive flexibility, and physical vitality. However, randomized controlled trials do not provide positive results, and in most of the cases TRT might not induce beneficial effects on cognitive function in elderly men. Discussion and conclusions. Since the lengthening of life expectancy, the prevalence rate of cognitive decline in elderly men is expected to increase remarkably over the next decade with considerable healthcare and economical concerns. Therefore, this remains a relevant clinical topic and further investigations are needed for clarifying the role of TRT especially in elderly men with hypogonadism.

Organic Diet and Intermittent Fasting are Associated With Improved Erectile Function

OBJECTIVE

To explore associations between dietary habits and erectile dysfunction (ED) in a cohort of patients presenting to a high-volume men's health clinic.

MATERIALS AND METHODS

All patients presenting to a high-volume men's health clinic between July 2018 and May 2019 were evaluated for their dietary habits and screened with the International Index of Erectile Function-5 (IIEF-5) and Androgen Deficiency in Aging Males (ADAM). The primary outcome measure was the impact of dietary habits on ED, defined as IIEF-5 <22. Stepwise logistic regressions were used to control for patient characteristics and relevant comorbidities.

RESULTS

Two hundred seventy-one patients were included. Primary reasons for visit were ED (110, 40.6%), hypogonadism (39, 14.4%), benign prostatic hyperplasia/lower urinary tract symptoms (80, 29.5%), and Peyronie's Disease (30, 11.1%). 176 (64.9%) followed no diet, while 11 (4.1%), 11 (4.1%), 8 (2.9%), and 11 (4.1%) were whole food only, low-carb/keto, vegetarian/pescatarian, and low-fat, respectively. Additionally, 105 (38.7%) reported organic foods consumption, while 51 (18.8%) had no processed food consumption, and 77 (28.4%) performed intermittent fasting. Patients reporting ED were more likely to be over the age of 65, had higher body mass index, more comorbidities, and less likely to report an organic diet or intermittent fasting. There were no correlations between diet and ADAM score. In adjusted analysis, patients reporting organic diet or intermittent fasting were significantly less likely to have ED.

CONCLUSION

This is the first study suggesting organic diet and intermittent fasting to be protective against ED. These results are hypothesis-generating and warrant further exploration.