Treatment strategies for diabetic patients suffering from erectile dysfunction

Erectile dysfunction is associated with defective L-cysteine/hydrogen sulfide pathway in human corpus cavernosum and penile arteries

H₂S signaling was proposed to participate in erectile physiology. L-cysteine (CYS)/H₂S pathway stimulation causes cGMP-dependent relaxation of human corpus cavernosum (HCC) and penile arteries (HPRA). The aim was to evaluate the impact of ED on CYS/H₂S pathway at functional and molecular level in human penile vascular tissues. NaHS- and CYS-induced responses were evaluated in HCC and HPRA from organ donors without ED (NoED, n = 29) and from ED patients undergoing penile prosthesis insertion (n = 45). cGMP accumulation and cystathionine β-synthase and cystathionine γ-lyase expression were also determined. NaHS-induced relaxations were slightly but significantly impaired in HCC but not in HPRA from ED patients. In contrast, CYS-induced relaxations were markedly impaired in HCC (E_max 67.6 ± 4.9% vs 46.2 ± 4.6%, P < 0.01) and HPRA (E_max 80.8 ± 4.0% vs 48.1 ± 8.6%, P < 0.05) from men with ED. Impairment of CYS-induced responses was observed even after separating diabetic ED patients. In HPRA from ED patients, CYS- but not NaHS-induced vasodilation was significantly associated to endothelial function measured as vasodilatory capacity of acetylcholine (ACh) in these preparations (r² = 0.481, P < 0.01). Impairment of CYS-induced relaxations was related to significant reduction in CYS-induced accumulation of cGMP in cavernosal tissue. Furthermore, the expression of H₂S synthesizing enzymes was significantly reduced in HCC from ED patients with respect to NoED. This was confirmed by immunofluorescence in HCC and HPRA sections. ED involves impairment of CYS/H₂S pathway in penile vascular tissues associated with decreased expression of H₂S generating enzymes, CBS and CSE. These evidences support a therapeutic potential for modulation of CYS/H₂S signaling in the management of ED.

Vacuum erection device in treatment of organic erectile dysfunction and penile vascular differences between patients with DM type I and DM type II

The aim of this study is to investigate changes in the vascular system and hemodynamics between patients with organic erectile dysfunction (ED) (DM type I and II), as well as to compare the quality of sexual life between those two groups after the treatment with vacuum erection device (VED). Study enrolled 50 males with DM, aged from 35 to 67 years, who have attended the urologic clinic due to inability to attain and maintain an erection of the penis sufficient to permit satisfactory sexual intercourse. Patients were using VED and six months later were assessed for therapy results. The International Index of Erectile Function (IIEF) was used to quantify erectile dysfunction. Alprostadil injection test was also used, with Doppler color flow imaging system, to evaluate the peak systolic velocity (PSV) and diameter of cavernosal artery (DCA). Significantly higher values of PSV were obtained in patients with DM type II. Also, DCA showed significant difference between two groups of patients. There was significant improvement in three items of IIEF after six months of treatment among both groups of examinees. Patients with DM type I had more serious risk for development of arteriogenic ED. VED could be a good alternative therapy for patients who denied peroral therapy.

Surgical outcomes and complications of Tube® (Promedon) malleable penile prostheses in diabetic versus non-diabetic patients with erectile dysfunction

OBJECTIVE

To evaluate surgical outcome, complications, and patients satisfaction with the Tube® (Promedon, Cordoba, Argentina) malleable penile prosthesis in diabetic and non-diabetic patients with refractory erectile dysfunction (ED).

PATIENTS AND METHODS

The records of 128 eligible patients who received Tube malleable penile prostheses at our institute between September 2008 and October 2015 were reviewed.

RESULTS

Of the 128 patients, who received Tube penile prostheses at our institute, 53 were diabetics and 75 were non-diabetics. Both groups of patients were comparable for mean age, education level, marital status, hospital stay, time to commencing sexual intercourse, and median follow-up. Complications included: inter-corporeal septal perforation (2.3%), glanular urethral injury (1.5%), acute urinary retention (3.9%), superficial wound infection (7%), penile discomfort (9.4%), and penile prostheses infection (5.5%). Moreover, 3.9% developed atrophy of the cavernosal tissue, 5.5% experienced bad cosmesis, 6.3% experienced ejaculatory disorders, and 2.3% developed bladder calculi. In all, 13 prostheses (9.4%) were removed, seven of them due to infection, three on the patients' demand and three due to mechanical failure. The satisfaction rates with the prostheses were 77.3% and 79.4% in the diabetic and non-diabetic patients, respectively; with an overall satisfaction rate of 78.5%. There was no significant difference in the complication rate or prostheses infection between diabetic and non-diabetic patients.

CONCLUSION

Tube malleable penile prostheses are associated with low complication and high satisfaction rates. There was no significant difference in the complication rate or prostheses infection between diabetic and non-diabetic patients. A prospective comparative study with a large number of patients is recommended.

Nebivolol potentiates the efficacy of PDE5 inhibitors to relax corpus cavernosum and penile arteries from diabetic patients by enhancing the NO/cGMP pathway

INTRODUCTION

The efficacy of oral pharmacotherapy for erectile dysfunction (ED) (i.e., type 5 phosphodiesterase[PDE5] inhibitors) is significantly reduced in diabetic patients. Nebivolol is a selective β1-blocker used for treatinghy pertension that has been shown to increase the efficacy of sildenafil to reverse ED in diabetic rats.

AIM

To evaluate the effects of nebivolol on the efficacy of the PDE5 inhibitors, sildenafil, tadalafil, and vardenafil to relax human corpus cavernosum (HCC) and vasodilate human penile resistance arteries (HPRA) from diabetic patients with ED (DMED). The influence of nebivolol on the capacity of these three PDE5 inhibitors to stimulate cyclic guanosine monophosphate (cGMP) production in HCC was also evaluated.

METHODS

HCC and HPRA were obtained from organ donors without ED (NEND; n = 18) or patients with diabetes undergoing penile prosthesis implantation (DMED; n = 19). Relaxations of HCC strips and HPRA to sildenafil,tadalafil, and vardenafil were evaluated in organ chambers and wire myographs. cGMP content in HCC was determined by ether extraction and quantification by ELISA.

MAIN OUTCOME MEASURES

Effects of nebivolol on PDE5 inhibitor-induced relaxation of HCC, vasodilation ofHPRA and cGMP accumulation in HCC.

RESULTS

Treatment with nebivolol (1 μM) significantly potentiated sildenafil-, tadalafil- and vardenafil-induced relaxations of HCC and vasodilations of HPRA from both NEND and DMED. Enhancement of relaxant capacity by nebivolol resulted in reversion of the impairment of PDE5 inhibition-induced responses in DMED and it was accompanied by enhancing the ability of PDE5 inhibitors to increase cGMP in HCC restoring reduced cGMP levelsin HCC from DMED.

CONCLUSIONS

Nebivolol potentiated the capacity of PDE5 inhibitors to relax vascular structures of erectile tissue from diabetic patients by enhancing the nitric oxide (NO)/cGMP pathway in these tissues. These effects suggest a potential therapeutic utility of nebivolol as an adjunct to PDE5 inhibitors for the treatment of ED associated with diabetes.

How to treat erectile dysfunction in men with diabetes: from pathophysiology to treatment

Erectile dysfunction (ED) is highly prevalent affecting at least 50 % of men with diabetes mellitus (DM). DM may cause ED through a number of pathophysiological pathways. These include neuropathy, endothelial dysfunction, cavernosal smooth muscle structural/functional changes, and hormonal changes. Lifestyle changes, diabetes control, and treatment of hypogonadism are important as the first step in ED management since there is no curative treatment for ED. Phosphodiesterase type 5 inhibitors (PDE5i) are the first-line treatment option. Intracavernous administration of vasoactive drugs is commonly used as a second-line medical treatment when PDE5i have failed. Alprostadil is the most widely used drug in this second-line setting. The combination of papaverine, phentolamine, and alprostadil represents the most efficacious intracavernous pharmacologic treatment option that may save non-responders to alprostadil. Penile prosthesis implantation can be considered in treatment refractory cases, with excellent functional and safety results in the properly informed patients.

Arterial erectile dysfunction: different severities of endothelial apoptosis between diabetic patients "responders" and "non responders" to sildenafil

BACKGROUND

The low pharmacological response to phosphodiesterase type 5 inhibitors represents an expression of higher endothelial damage in certain categories of patients with erectile dysfunction and high cardiovascular risk. The present study evaluated this objective in type 2 diabetic patients with erectile dysfunction, classified as "non responders" to Sildenafil.

METHODS

Eighteen "responder" and twelve "non responder" type 2 diabetic patients were evaluated, relatively to different levels of endothelial damage, through the diagnostic use of a new immunophenotype of circulating endothelial progenitor cells (CD45neg/CD34pos/CD144pos) and endothelial microparticles (CD45neg/CD144pos/Annexin Vpos), recently developed and published by our group.

RESULTS

"Non responder" patients showed a significant higher severity [8.0±3.0 (International Index of Erectile Function-abbreviated version with 5 questions) vs 14.0±3.0] and duration (10.0±2.0 vs 7.0±2.0 years) of erectile dysfunction, higher level of penile arterial insufficiency (peak systolic velocity=13.0±16.0 vs 28.0±26.0cm/s; acceleration time=153±148 vs 125±128 mm/s) and finally a significant higher level of endothelial apoptosis [0.15±0.13 vs 0.05±.0.03% (serum concentrations of endothelial microparticles)] associated with higher serum concentrations of circulating late immunophenotype of endothelial progenitor cells (0.40±0.35 vs 0.12±.0.10%).

CONCLUSIONS

The results of this study corroborate the clinical value of the low clinical response to phosphodiesterase type 5 inhibitors in the treatment of erectile dysfunction in the patients with high cardiovascular risk profile, such as diabetics. In addition, the markers used in this study confirm their potential application in clinical practice as useful indicators of endothelial alteration. However, in the future we will have to assess a larger number of patients and for a longer period of observation in order to better understand the causal and temporal relations.

The resurgence of the vacuum erection device (VED) for treatment of erectile dysfunction

INTRODUCTION

Vacuum erection devices (VEDs) have been approved in the United States since 1982 and offer a viable alternative to oral phosphodiesterase type 5 inhibitors (PDE5i), injections and transurethral suppositories. Studies have demonstrated efficacy in erectile dysfunction (ED) associated with a variety of conditions. More recently, this modality has been evaluated in initial phosphodiesterase inhibitor nonresponders as well as for post-prostatectomy penile rehabilitation.

AIM

This article provides a detailed overview of the history of VEDs, a review of the literature, and a concise description of their new applications in modern urological practice.

METHODS

A retrospective review of publications relevant to the field of VEDs.

MAIN OUTCOME MEASURES

Review of the historical milestones, evolution, and modern utilization of VEDs in modern urological protocols.

RESULTS

Studies have demonstrated efficacy in ED associated with a variety of conditions. Early penile rehabilitation after surgery for prostate cancer with the VED appears to improve erectile function and penile length. Adverse events are transient and not serious.

CONCLUSIONS

The VED has continued to show efficacy for treatment of ED due to various etiologies and should be considered an attractive second-line therapy. In select cases such post-prostatectomy penile rehabilitation, as well as in men who cannot use a PDE5i, the vacuum device should be considered first-line treatment.

The effects of long-term administration of tadalafil on STZ-induced diabetic rats with erectile dysfunction via a local antioxidative mechanism

Type 5 phosphodiesterase inhibitors (PDE5Is) are well known being effective via the nitric oxide and cyclic guanosine monophosphate (NO-cGMP) pathway and are widely used in the treatment of diabetic erectile dysfunction (ED). However, it is unclear whether other pathways may be involved in the treatment of diabetic ED with PDE5Is. The purpose of this study was to clarify the role of antioxidants in diabetic ED treatment through the long-term administration of PDE5Is. Three groups of Sprague-Dawley rats were utilized: Group N, the normal control; Group D, streptozotocin (STZ)-induced diabetic rats as a control; and Group D+T, STZ-induced diabetic rats who received oral administration of tadalafil for 8 weeks. Erectile function was assessed by intracavernous pressure (ICP) and mean arterial pressure (MAP) during electrical stimulation of the cavernous nerve before euthanasia. The levels of malondialdehyde (MDA), superoxide dismutase (SOD) and mitochondrial membrane potential (MMP) of cavernous tissue were assessed by biochemical analysis. The morphology of mitochondria was observed by electron microscopy. The ICP/MAP ratio was higher in Group D+T than in Group D (P<0.05). The levels of MDA decreased and the activities of SOD increased in Group D+T in comparison with Group D (P<0.05). The mitochondrial membrane potential level of cavernous tissue in diabetic rats was partially recovered by tadalafil treatment for 8 weeks. The morphology changes of mitochondria were also remarkably ameliorated in Group D+T. Collectively, the long-term administration of tadalafil in diabetic rats partially reduced oxidative stress lesions of the penis via a local antioxidative stress pathway. Long-term dosages of tadalafil given once daily beginning soon after the onset of diabetes may aid in preventing rats from developing diabetic ED.

The symptomatic management of multiple sclerosis

The management of multiple sclerosis (MS) revolves around disease management, symptom management, and person management. Of these, symptom management takes up the bulk of the time of the practicing physician. Some symptoms are easily managed whereas others are more difficult. Decisions have often to be made on whether to treat or to wait and watch. This article discusses the varied symptoms of MS and the approaches to management, which involves rehabilitation, pharmacological treatments, and surgical procedures. The skilled physician managing MS should be familiar with the multiple approaches to improving the quality of life of those with MS. After the diagnosis has been established and the decisions regarding treatment approaches have been made, the talk in a typical office appointment for MS usually turns to symptom management. Thus, the majority of management decisions made by the clinician revolve around that important topic. It is symptom management that will determine quality of life for those with MS, It is the basis for improving function, and, up until twenty years ago, it was the only basis for treating MS. Now, however, we can approach treatment by disease management, symptom management, and person management. The MS specialist must be well versed in all three areas.

Losartan, an Angiotensin type I receptor, restores erectile function by downregulation of cavernous renin-angiotensin system in streptozocin-induced diabetic rats

INTRODUCTION

The high incidence of erectile dysfunction (ED) in diabetes highlights the need for good treatment strategies. Recent evidence indicates that blockade of the angiotensin type I receptor (AT1) may reverse ED from various diseases.

AIM

To explore the role of cavernous renin-angiotensin system (RAS) in the pathogenesis of diabetic ED and the role of losartan in the treatment of diabetic ED.

METHODS

The AT1 blocker (ARB) losartan (30 mg/kg/d) was administered to rats with streptozocin (65 mg/kg)-induced diabetes. Erectile function, cavernous structure, and tissue gene and protein expression of RAS in the corpora cavernosa were studied.

MAIN OUTCOME MEASURE

We sought to determine the changes of cavernous RAS in the condition of diabetes and after treatment with losartan.

RESULTS

RAS components (angiotensinogen, [pro]renin receptor, angiotensin-converting enzyme [ACE], and AT1) were expressed in cavernosal tissue. In diabetic rats, RAS components were upregulated, resulting in the increased concentration of angiotensin II (Ang II) in the corpora. A positive feedback loop for Ang II formation in cavernosum was also identified, which could contribute to overactivity of cavernous RAS in diabetic rats. Administration of losartan blocked the effect of Ang II, downregulated the expression of AT1 and Ang II generated locally, and partially restored erectile function (losartan-treated group revealed an improved intracavernous pressure/mean systemic arterial pressure ratio as compared with the diabetic group (0.480 +/- 0.031 vs. 0.329 +/- 0.020, P < 0.01). However, losartan could not elevate the reduced smooth muscle/collagen ratio in diabetic rats.

CONCLUSIONS

The cavernous RAS plays a role in modulating erectile function in corpora cavernosa and is involved in the pathogenesis of diabetic ED. ARB can restore diabetic ED through downregulating cavernous RAS.