Erectile dysfunction in men with diabetes mellitus

Minimising the risk of device infection in penile prosthetic surgery: a UK perspective

We have reviewed articles published on penile prosthetic infection in Medline and EMBASE databases from 2000 to 2012 with the intention of signposting ‘best evidence’ for the UK prosthetic implanter. Using the Oxford Centre for Evidence-based Medicine Levels of Evidence (LE), no paper exceeded an LE of 2b and the majority were LE 4 (case series) and LE 5 (expert opinion). This is not surprising from a UK perspective since HES data for 2009 to 2010 reported 263 penile prosthetic surgeries performed in 35 hospitals, with only five hospitals performing 15 or more. Our literature review suggests that the use of antibiotic-coated IPPs and measures aimed at reducing inoculating bacteria into the surgical wound with alcohol skin preparation, a no-touch technique and peri-operative antibiotic use are most important in minimising the risk of device infection. The use of post-operative antibiotics is contentious (LE 5). It remains unproven whether diabetics have a higher rate of prosthetic infection compared to nondiabetics. In cases of re-implantation for mechanical failure, it remains debatable whether a washout technique should be used and indeed uncertainty remains regarding the pathological role of biofilm in the causation of device infection in this scenario. A washout technique during salvage penile prosthetic surgery for device infection is advocated. Further research on biofilm may offer the best chance of reducing the incidence of device infections overall.

Erectile dysfunction in type 2 diabetic men: relationship to exercise fitness and cardiovascular risk factors in the Look AHEAD trial

INTRODUCTION

Determinants of erectile dysfunction in diabetic men have not been adequately investigated as potential mediators of change.

AIM

To determine the prevalence and correlates of erectile dysfunction (ED) in overweight men with type 2 diabetes in the multicenter, Look AHEAD trial (Action for Health in Diabetes).

MAIN OUTCOME MEASURES

International Index of Erectile Function (IIEF), self-reported use of phosphodiesterase type 5 inhibitors, laboratory measures of adiposity, cardiometabolic parameters, and exercise fitness.

METHODS

Male participants aged 45-75 in the Look AHEAD trial in a committed relationship were recruited for an ongoing study of sexual function and diabetes. Eligible participants completed the IIEF questionnaire and provided updated information on use of medical treatments for sexual dysfunction. Baseline sexual function results for participants in the male ancillary study are reported here; intervention data and results for female participants are presented elsewhere.

RESULTS

A total of 373 eligible male participants completed all sexual function questionnaires, of whom 263 (68.7%) were sexually active at the time of the study. Almost half (49.8%) of the men reported mild or moderate degrees of ED, and 24.8% had complete ED. Among sexually active participants, 42.6% had sought medical help for their problem, and 39.7% reported use of ED medications. ED was significantly associated with age (odds ratio [OR] = 1.05; confidence interval [CI]: 1.01-1.10) baseline HbA(1c) (OR = 1.31; CI: 1.05-1.63), hypertension history (OR = 2.41; CI: 1.34-4.36), and metabolic syndrome (OR = 3.05, CI: 1.31-7.11). Of note, cardiorespiratory fitness was found to be protective of ED in a multivariable analysis (OR = 0.61; P < 0.001).

CONCLUSIONS

ED is prevalent in this sample of obese, type 2 diabetic men in the Look AHEAD study. Cardiovascular risk factors were highly associated with ED in this population, and cardiorespiratory fitness was protective in this analysis.

Arginase alteration in the reproductive system of alloxan-diabetic dogs

This study was conducted to evaluate possible alteration in the activity of arginase, an important enzyme of cell proliferation and vascular smooth muscle contraction regulator in diabetics, that may be correlated with low fertility in diabetic patients. In this investigation, 6 apparently healthy adult male dogs were selected and divided in two groups, diabetics and non-diabetics. Diabetes mellitus was induced in one group by intravenous (IV) injection of alloxan (100 mg/kg). Dogs with a fasting blood glucose (FBS) of more than 200 mg/dl were considered to be diabetic. Four weeks following induction of diabetes mellitus, the animals in both groups were anesthetized by an IV injection of sodium thiopental. Livers and whole reproductive systems, including the testes, penis, urethra, and prostate, were dissected. The epididymides, corpus cavernosum, corpus spongiosum, penile urethra, and vas deferens were also dissected and removed from the reproductive system. Arginase activity and total protein were measured by the urea and Lowry's methods respectively in above mentioned sections. Plasma testosterone was determined by the radioimmunoassay method. The results showed significantly (P<0.05) increased arginase specific activity (ASA) in the liver, epididymis, prostate, corpus cavernosum and corpus spongiosum of the diabetic dogs. In the reproductive system of the diabetic dog, the maximum and minimum ASA was seen in the corpus cavernosum and testes, respectively (105.12 +/- 8.76 vs. 25.0 +/- 0.55). No such variation was observed in the ASA of normal dogs (39.0 +/- 5.47 vs. 25.0 +/- 5.47). There was no significant difference in plasma testosterone level between the groups. In conclusion, diabetes increased the ASA in liver, prostate, epididymis, corpora cavernosa, and corpora spongiosum of the male dogs and may contribute to erectile dysfunction or low fertility in diabetics.

Protection of testicular dysfunctions by MTEC, a formulated herbal drug, in streptozotocin induced diabetic rat

Single injection of streptozotocin (STZ) resulted diabetes mellitus which was reflected here by the levels of fasting blood glucose and serum insulin. Moreover, this experimental diabetes also resulted testicular dysfunctions evaluated by count, viability and motility of sperm as well as by the activities of key enzymes for androgen synthesis. Diabetes induced testicular oxidative stress has been indicated here by the monitoring of testicular peroxidase and catalase activities as well as by quantification of TBARS and CD of testis. Testicular glucose was increased and leydig cell nuclear area was decreased in STZ induced diabetes. Treatment of herbal formulated drug named as MTEC consist of aqueous-methanol extract of Musa paradisiaca, Tamarindus indica, Eugenia jambolana and Coccinia indica to streptozotocin induced diabetic rat at the ratio of 2:2:1:1 at the dose of 60 mg/d for two times a day for 14 d resulted a significant protection in fasting blood glucose and serum insulin levels (p<0.05) along with correction of testicular above parameters towards the control level (p<0.05). This herbal formulated drug has no general toxic effects on the body weight, as well as on the activities of serum glutamate and pyruvate transaminases in serum. The results support the validity of this herbal drug for the management of testicular disorders noted in diabetic state.

Oxidative stress and antioxidant therapy: their impact in diabetes-associated erectile dysfunction

Oxidative stress is believed to affect the development of diabetic-associated vasculopathy, endothelial dysfunction, and neuropathy within erectile tissue. Our hypothesis is that, given adequate concentrations of the oxygen free radical scavenger vitamin E, enhanced levels of circulating nitric oxide (NO) should improve erectile function with the potential for a synergistic effect with a phosphodiesterase type 5 (PDE5) inhibitor. Twenty adult male Sprague-Dawley streptozotocin-induced (60 mg/kg intraperitoneally) diabetic rats were placed in 4 therapeutic groups (n = 5 per group) as follows: 1) peanut oil only (diabetic control), 2) 20 IU of vitamin E per day, 3) 5 mg/kg of sildenafil per day, and 4) vitamin E plus sildenafil using oral gavage for 3 weeks. In addition, 5 age-matched rats served as normal nondiabetic controls (normal). Erectile function was assessed by measuring the rise in intracavernous pressure (ICP) following cavernous nerve electrostimulation. Penile tissue was evaluated for neuronal NO synthase (nNOS), smooth muscle alpha-actin, nitrotyrosine, and endothelial cell integrity. Urine nitrite and nitrate (NOx) concentration was quantified, and electrolytes were tested by a serum biochemistry panel. A significant decrease in ICP was recorded in the diabetic animals, with improvement measured in the animals receiving PDE5 inhibitors either with or without vitamin E; the controls had a pressure of 54.8 +/- 5.3 cm H2O, the vitamin E group had a pressure of 73.5 +/- 6.6 cm H2O, the sildenafil group had a pressure of 78.4 +/- 10.77 cm H2O, and the vitamin E plus sildenafil group had a pressure of 87.9 +/- 5.5 cm H2O (P <.05), compared with the normal cohorts at 103.0 +/- 4.8 cm H2O. Histoexaminations showed improved nNOS, endothelial cell, and smooth muscle cell staining in the vitamin E plus sildenafil group compared to the control animals. Urine NOx increased significantly in all the diabetic groups but was blunted in the vitamin E and vitamin E plus sildenafil groups. A significant increase in positive staining for nitrotyrosine was observed in the vitamin E plus sildenafil group. Vitamin E enhanced the therapeutic effect of the PDE5 inhibitor in this study, supporting the potential use of oxygen free radical scavengers in salvaging erectile function in diabetic patients.

Effect of PDE5 inhibition combined with free oxygen radical scavenger therapy on erectile function in a diabetic animal model

Phosphodiesterase (PDE) inhibitors represent an important advance in the treatment of erectile dysfunction (ED). In spite of widespread use and generally good efficacy, as a class they remain ineffective in 15-57% of men. Specific cohorts of patients with severe vascular or neurogenic basis to their ED, such as diabetic men or those who have undergone radical pelvic surgery, demonstrate lower response rates with PDE inhibition treatment. We believe that circulating levels of nitric oxide (NO) may be enhanced through delivery of adequate concentrations of free oxygen radical scavenger molecules such as vitamin E. Higher levels of NO, theoretically, should produce increased penile blood flow with the potential for a synergistic effect when combined with a PDE5 inhibitor. With this hypothesis in mind, 20 adult male Sprague-Dawley streptozotocin-induced (60 mg/kg i.p.) diabetic rats were divided into four therapeutic groups (n=5). Group I--control animals received peanut oil, group II--vitamin E 20 IU/day, group III--sildenafil 5 mg/kg/day and group IV--vitamin E 20 IU/day plus sildenafil 5 mg/kg/day, by oral gavage daily for 3 weeks. Erectile function was assessed as a rise in intracavernous pressure following cavernous nerve electrostimulation. Penile tissue was harvested to determine the changes in tissue morphology including neuronal nitric oxide synthase, smooth muscle alpha-actin and endothelial cell integrity. PDE5 protein content and activity were measured. Significant increases in intracavernous pressure were measured in the animals receiving combined vitamin E plus sildenafil treatment. Immunohistochemical staining showed increases of neuronal nitric oxide synthase, endothelial cell and smooth muscle cell staining. Western blot analysis did not show significant differences of PDE5 protein between the groups. However, higher PDE5 activity was measured in the sildenafil group and lower activity of PDE5 was recorded in the cohort receiving vitamin E with sildenafil. Vitamin E enhanced the therapeutic effect of the PDE5 inhibitor in a meaningful way in this animal model of diabetes. This study indicates a potential means of salvaging erectile function among patients who are refractory to sildenafil.

Association of type and duration of diabetes with erectile dysfunction in a large cohort of men

OBJECTIVE

Differences in risk of erectile dysfunction (ED) by characteristics of diabetes among older men are not well understood. We examined the association of type and duration of diabetes with erectile function in men >50 years of age in a large prospective cohort study.

RESEARCH DESIGN AND METHODS

Subjects included 31,027 men aged 53-90 years in the Health Professionals Follow-Up Study cohort. On a questionnaire mailed in 2000, participants rated their ability (without treatment) in the past 5 years to have and maintain an erection sufficient for intercourse. Men who reported poor or very poor function were considered to have ED. Diabetes information was ascertained via self-report and documented with supplementary medical data.

RESULTS

Men with diabetes had an age-adjusted relative risk (RR) of 1.32 (95% CI 1.3-1.4) for having ED compared with men without diabetes. In multivariable regression analyses, men with type 1 and type 2 diabetes were at a significantly higher risk for ED (type 1 diabetes RR = 3.0, 95% CI 1.5-5.9; type 2 diabetes RR = 1.3, 1.1-1.5) than nondiabetic men. Men with type 2 diabetes had an increasingly greater risk of ED with increased duration since diagnosis (trend test P value <0.0001) (RR = 1.7, 95% CI 1.1-2.7, for men diagnosed >20 years previously).

CONCLUSIONS

For men over age 50 years, increasing duration of diabetes was positively associated with increased risk of ED relative to nondiabetic subjects. This association persisted despite the higher prevalence of other comorbid conditions. ED prevention and diabetes management efforts are likely to go hand-in-hand.

The treatment of hypertension in patients with erectile dysfunction

Hypertension is another predictor of erectile dysfunction (ED). This is further evidence supporting a link between the pathogenesis of atherosclerotic disease and ED. In one study (TOMHS) involving hypertensive patients, the incidence of ED was 14.4%. The drugs used to treat hypertension may cause ED. However, there is little trial-based evidence to indicate which drugs are more likely to cause this side effect. In general, thiazide diuretics and beta-blockers seem to cause ED more often. In contrast, the alpha-blocker, doxazosin, has not been associated with an increased incidence of ED as a side effect. Doxazosin also improves urinary flow in patients with benign prostatic hyperplasia (BPH). This condition is common in elderly men as is hypertension and ED. Therefore, doxazosin may present a special advantage among this group of patients. This alpha-blocker would also be a good choice in patients with impaired glucose tolerance/diabetes because it improves insulin sensitivity. Moreover, ED and hypertension are more prevalent among diabetics. On a more speculative note, doxazosin may potentiate the therapeutic impact of specific treatments for ED.

Impaired ascendant central pathways conduction in impotent diabetic subjects

OBJECTIVES

Diabetic impotence is generally due to peripheral neuropathy, but a central pathway impairment has also been suggested. We evaluated somatosensory transmission in a group of impotent diabetic men to assess the role of central nervous system (CNS) involvement.

MATERIALS AND METHODS

Somatosensory evoked potentials (SEPs) of pudendal (pdn) and posterior tibial (ptn) nerves were recorded in 74 patients. Type and duration of diabetes, severity of sexual dysfunction, medium term metabolic control, occurrence of microangiopathic chronic complications and autonomic neuropathy were evaluated.

RESULTS

Our data show an impairment of central conduction times in pdn (25.7%) and ptn (39.2%) greater than peripheral nervous impairment (pdn 12.2%, ptn 8.1%), in impotent diabetic patients without any further major complication. Central nervous conduction delay resulted to be correlated with poor glycemic control. Significant evident autonomic dysfunction was found only in a minority of cases.

CONCLUSION

Our data might suggest that altered conduction along CNS and somatic peripheral neuropathy might develop independently. We confirm the hypothesis of a "central diabetic neuropathy" and suggest that central sensory pathways involvement, not related to peripheral impairment, could play a role in the pathogenesis of erectile dysfunction in diabetic patients.

Use of glycosylated hemoglobin to identify diabetics at high risk for penile periprosthetic infections

We report an 18-month prospective study of 90 patients undergoing penile prosthesis implantation to evaluate a possible cause-and-effect relationship between degree of diabetic control and the risk of infection complicating the operation. Long-term diabetic control was objectively evaluated by measurement of the glycosylated hemoglobin of the patient, which is known to provide an objective value for degree of control for the preceding 60 to 90 days. Of 90 patients 5 (5.5%) had a periprosthetic infection requiring explantation and all infections occurred in the 32 diabetics (36%) in the population (p less than 0.009). Of the 32 diabetics 13 (41.1%) were poorly controlled with time as demonstrated by a glycosylated hemoglobin level of greater than 11.5% and 4 of the infections occurred in this group. Of the 19 remaining controlled diabetics (glycosylated hemoglobin level less than 11.5%) only 1 infection occurred. Therefore, infection occurred in 31% of the poorly controlled versus 5% of the adequately controlled patients (p less than 0.0003). Measurement of glycosylated hemoglobin values appears to be a useful tool to evaluate diabetic patients before implantation of a penile prosthesis. Patients with a glycosylated hemoglobin level of 11.5% or greater should be more optimally controlled before undergoing implantation in an effort to avoid infectious complications.

Cigarette smoking: an independent risk factor for atherosclerosis in the hypogastric-cavernous arterial bed of men with arteriogenic impotence

We investigated the relationship between cigarette smoking and atherosclerosis of the hypogastric-cavernous arterial bed by evaluating arteriograms of young impotent men referred for selective pudendal angiography. Those patients with hemodynamically significant atherosclerosis had smoked more pack-years than had patients without arterial disease. These differences were statistically significant (p less than 0.05) for the common penile artery (32.8 pack-years, 40 patients versus 22.3 pack-years 57 patients) and the dorsal artery (31.3 pack-years, 48 patients versus 22.0 pack-years, 49 patients). The effect of cigarette smoking as an independent risk factor for atherosclerotic disease in the hypogastric-cavernous arterial bed was evaluated as well. When controlled for age, trauma history, hypertension and diabetes, cigarette smoking was independently associated with atherosclerosis in the internal pudendal artery (p less than 0.05). The relative risk (and 95% confidence interval) of developing internal pudendal artery atherosclerosis for each 10 pack-years smoked was 1.31 (1.05 to 1.64). A third analysis investigated the potential interactive effects of cigarette smoking and pelvic or perineal trauma. A significantly higher incidence (p less than 0.05) of cavernous artery atherosclerosis was found among smokers with a history of chronic perineal trauma (33 patients) compared to nonsmokers with a similar history (25 patients). The findings of this study indicate that cigarette smoking is an independent risk factor in the development of atherosclerotic lesions in the internal pudendal and common penile arteries of young impotent men. Cigarette smoking appears to predispose these patients to early atherosclerotic lesions in the cavernous artery following chronic perineal trauma.

Impotence in diabetic men

Studies relating to pathogenetic mechanisms resulting in impotence in diabetic subjects have been reviewed. Erectile dysfunction was reported to occur in 50 to 75 percent of diabetic patients and the prevalence appeared to increase with age. Contributions of vascular, endocrine, and neurologic system alterations result in this disturbing condition, but a detailed analysis of all the parameters was not found in any individual study. In our review of 301 veterans presenting to a sexual dysfunction clinic, the clinical and hormonal alterations in the diabetic patients closely resemble those seen in nondiabetic impotent subjects. Atherosclerotic vascular changes play an important predisposing role in the development of impotence. A difference exists between the prevalences of associated medical conditions in diabetic patients taking insulin, compared with those receiving oral agents or receiving dietary management. The high prevalence of impotence in diabetic patients seems to be due to the high prevalence of its vascular complications. Considering the availability of useful therapeutic approaches, it is mandatory to evaluate all diabetic men for the presence of impotence.