Neurologic erectile dysfunction

Anatomy, physiology, and evaluation: Bowel, bladder, and sexual disorders

Our present understanding of bowel and bladder control has changed dramatically with the introduction of functional imagining technologies such as PET, SPECT, fMRI scanning, and near-infrared spectroscopy of the brain. Urologists tend to see control of urination and defecation as processes that occurred at or below the level of the pons for the most part. In this chapter, we examine the control of storing and emptying of urine and stool from what will be a more neurocentric perspective, integrating the frontal lobes into the process and moving beyond the pons on which most of the literature has focused in the past. Utilizing this approach gives us a better understanding of why there is an overlapping of neuropsychiatric problems in many patients with voiding dysfunction.

Impact of COVID 19 on erectile function

Purpose: COVID-19, a novel infection, presented with several complications, including socioeconomical and reproductive health challenges such as erectile dysfunction (ED). The present review summarizes the available shreds of evidence on the impact of COVID-19 on ED.Materials and methods: All published peer-reviewed articles from the onset of the COVID-19 outbreak to date, relating to ED, were reviewed. Results: Available pieces of evidence that ED is a consequence of COVID-19 are convincing. COVID-19 and ED share common risk factors such as disruption of vascular integrity, cardiovascular disease (CVD), cytokine storm, diabetes, obesity, and chronic kidney disease (CKD). COVID-19 also induces impaired pulmonary haemodynamics, increased ang II, testicular damage and low serum testosterone, and reduced arginine-dependent NO bioavailability that promotes reactive oxygen species (ROS) generation and endothelial dysfunction, resulting in ED. In addition, COVID-19 triggers psychological/mental stress and suppresses testosterone-dependent dopamine concentration, which contributes to incident ED.Conclusions: In conclusion, COVID-19 exerts a detrimental effect on male reproductive function, including erectile function. This involves a cascade of events from multiple pathways. As the pandemic dwindles, identifying the long-term effects of COVID-19-induced ED, and proffering adequate and effective measures in militating against COVID-19-induced ED remains pertinent.

Sexual Function of Men and Women With Spina Bifida: A Scoping Literature Review

INTRODUCTION

As most adults with spina bifida are either sexually active or interested in becoming sexually active, providers should understand how spina bifida impacts sexual function and options for treatment.

OBJECTIVES

The objective of this study is to summarize the current literature describing how features of spina bifida impact sexual function in men and women, effective available treatment options for sexual dysfunction, and to identify research gaps.

METHODS

Searches were conducted in PubMed, CINAHL Complete, PsychInfo, Cochrane Central, Scopus, and Web of Science Core Collection databases using keywords related to spina bifida and sexual function. 34 primary research studies were included.

RESULTS

Most men (56-96%) can achieve an erection, although it may be insufficient for penetration. Although 50-88% ejaculate, it is often dripping, retrograde, or insensate. Twenty percent to 67% achieve orgasm. Generally, men with lower lesions and intact sacral reflexes have better outcomes, although some men with all levels of lesion report good function. Sildenafil is efficacious at treating erectile dysfunction for most men. The "TO-MAXimize sensation, sexuality, and quality of life" procedure may improve sexual function in selected men with low-level lesions. Female sexual function and treatment is less well understood. Women may experience decreased arousal, difficulties with orgasm, and pain. No treatment has been studied in women. Bowel and bladder incontinence during intercourse appears to be bothersome to men and women. Although both men and women have diminished sexual satisfaction, their sexual desire appears to be least impacted. Present studies are limited by studies' small, heterogeneous populations, the misuse of validated questionnaires in the sexually inactive population, and the lack of a validated questionnaire specific to people with spina bifida.

CONCLUSIONS

Spina bifida impacts the sexual function of both men and women. Future studies should seek a better understanding of female sexual function and treatment, use validated questionnaires appropriately, and ultimately create a validated sexual function questionnaire specific to this population. Streur CS, Corona L, Smith JE, et al. Sexual Function of Men and Women With Spina Bifida: A Scoping Literature Review. Sex Med Rev 2021;9:244-266.

Association of Peripheral Neuropathy with Erectile Dysfunction in US Men

BACKGROUND

Peripheral neuropathy and erectile dysfunction are common conditions that have both been linked to cardiovascular disease and its risk factors, especially diabetes. The aim of this study was to assess the association of large-fiber peripheral neuropathy with erectile dysfunction in adult US males with and without diabetes.

METHODS

We included all men aged ≥40 years from the 2001-2002 National Health and Nutrition Examination Survey (NHANES) with data on erectile dysfunction and peripheral neuropathy (n = 1213, including 206 men with diabetes). Erectile dysfunction was assessed by a single question during a self-paced, computer-assisted self-interview. Peripheral neuropathy was evaluated using standardized 10-g monofilament testing, which assesses lower extremity sensation. We used logistic regression to examine the association of peripheral neuropathy with erectile dysfunction overall and stratified by diabetes status, adjusting for demographic and cardiovascular risk factors.

RESULTS

The prevalence of peripheral neuropathy was 26.1% (51.2% in men with diabetes and 22.5% in men without diabetes). There was a significant independent association of peripheral neuropathy with erectile dysfunction overall (odds ratio [OR] 1.71, 95% confidence interval [CI], 1.20-2.43) and among US adult men without diabetes (OR 1.68; 95% CI, 1.11-2.56). The association in adults with diabetes was not statistically significant (OR 1.29; 95% CI, 0.39-4.26), possibly owing to limited power in this subgroup.

CONCLUSIONS

Our study suggests that decreased lower extremity sensation, even in the absence of diabetes, is common and a novel risk factor for erectile dysfunction.

Therapeutic potential of Mucuna pruriens (Linn.) on ageing induced damage in dorsal nerve of the penis and its implication on erectile function: an experimental study using albino rats

OBJECTIVE

To study the effect of ethanolic seed extract of Mucuna pruriens on damaged dorsal nerve of the penis (DNP) in aged rat in relation to penile erection.

METHODS

The rats were divided into four groups Young (3 months), Aged (24 - 28 months), Aged + M. pruriens, and Young + M. pruriens (200 mg/kg b.w/60 days) and were subjected to the hypophysial - gonadal axis, nerve conduction velocity (NCV), and penile reflex. DNP sections were stained with nitric oxide synthase (nNOS), nicotinamide adenine dinucleotide phosphate (NaDPH) diaphorase, androgen receptor (AR), and osmium tetroxide. Terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) staining, electron microscopy(EM) and histometric analyses were done.

RESULTS

Significant disturbance in hypophysial - gonadal axis was noted in aged rat. With reduced number of myelinated fibers, diameter, vacuolization, indentation of the myelin sheath, and degeneration. nNOS and its cofactor (NaDPH diaphorase) were reduced in aged rat DNP. NCV was slow in aged rats and concomitant poor penile reflex was also noted. AR showed reduced expression in aged rat DNP when compared to young and control groups. TUNEL positive cells were increased in aged rat DNP. These pathological changes were remarkably reduced or recovered in M. pruriens treated aged rats.

CONCLUSIONS

The results indicate a multi-factorial therapeutic activity in penile innervations towards sustaining the penile erection in the presence of the extract in aged rats and justifying the claim of traditional usage.

Pharmacology and perspectives in erectile dysfunction in man

Penile erection is a perfect example of microcirculation modulated by psychological factors and hormonal status. It is the result of a complex neurovascular process that involves the integrative synchronized action of vascular endothelium; smooth muscle; and psychological, neuronal, and hormonal systems. Therefore, the fine coordination of these events is essential to maintain penile flaccidity or allow erection; an alteration of these events leads to erectile dysfunction (ED). ED is defined as the consistent or recurrent inability of a man to attain and/or maintain a penile erection sufficient for sexual activity. A great boost to this research field was given by commercialization of phosphodiesterase-5 (PDE5) inhibitors. Indeed, following the discovery of sildenafil, research on the mechanisms underlying penile erection has had an enormous boost, and many preclinical and clinical papers have been published in the last 10 years. This review is structured to provide an overview of the mediators and peripheral mechanism(s) involved in penile function in men, the drugs used in therapy, and the future prospective in the management of ED. Indeed, 30% of patients affected by ED are classified as "nonresponders," and there is still an unmet need for therapeutic alternatives. A flowchart suggesting the guidelines for ED evaluation and the ED pharmacological treatment is also provided.

Objective Measurement and Monitoring of Nonmotor Symptoms in Parkinson's Disease

The comprehensive evaluation of nonmotor symptoms (NMS) in Parkinson's disease (PD) starts with the awareness of physicians, patients, and caregivers on their nature, clinical presentation, and effect on patient's daily activities and quality of life. This awareness can be better achieved if the symptoms can be visualized, measured, and monitored. As NMS are largely subjective in nature, a majority of them cannot be visualized (unlike tremor, which is easily seen), making their identification and quantification difficult. While symptoms are nonmotor, it does not mean that they are not measurable, as many NMS are integral to motor symptoms of Parkinson's, yet often neglected. In this review, we attempt to provide the most up-to-date and comprehensive literature review on the objective measurement and monitoring of NMS in PD. The aim is to make it clinically relevant by approaching NMS by domains as identified in the NMS Questionnaire. A section on the assessment of nonmotor fluctuations is also included, providing prospects for future objective monitoring. With the advances of technology, it is likely that many NMS will have objective outcomes, thus making these symptoms easily measurable and hopefully lead to future clinical trials that incorporate nonmotor outcomes. Nevertheless, it still requires a physician's judgment to determine which method, scales, objective measures, or monitoring devices or a combination of these is most appropriate to the individual patient in order to answer a particular clinical question.

Nonmotor symptoms of Parkinson’s disease

Nonmotor symptoms occur commonly in Parkinson's disease (PD) patients and are frequently under-recognized and undertreated. Symptoms include sleep abnormalities, fatigue, autonomic disturbances, mood disorders and cognitive dysfunction. Early recognition and treatment of nonmotor symptoms in PD is critical to providing optimal management. A new screening questionnaire and the revised Unified PD Rating Scale should assist healthcare providers to better identify and evaluate these symptoms. This article reviews the identification and treatment of nonmotor symptoms in PD.

Diabetes and sexual dysfunction: current perspectives

Diabetes mellitus is one of the most common chronic diseases in nearly all countries. It has been associated with sexual dysfunction, both in males and in females. Diabetes is an established risk factor for sexual dysfunction in men, as a threefold increased risk of erectile dysfunction was documented in diabetic men, as compared with nondiabetic men. Among women, evidence regarding the association between diabetes and sexual dysfunction are less conclusive, although most studies have reported a higher prevalence of female sexual dysfunction in diabetic women as compared with nondiabetic women. Female sexual function appears to be more related to social and psychological components than to the physiological consequence of diabetes. Hyperglycemia, which is a main determinant of vascular and microvascular diabetic complications, may participate in the pathogenetic mechanisms of sexual dysfunction in diabetes. Moreover, diabetic people may present several clinical conditions, including hypertension, overweight and obesity, metabolic syndrome, cigarette smoking, and atherogenic dyslipidemia, which are themselves risk factors for sexual dysfunction, both in men and in women. The adoption of healthy lifestyles may reduce insulin resistance, endothelial dysfunction, and oxidative stress - all of which are desirable achievements in diabetic patients. Improved well-being may further contribute to reduce and prevent sexual dysfunction in both sexes.

Office-based management of impotence and Peyronie's disease

Erectile dysfunction (ED) impacts more than 50% of men older than 40 years; Peyronie disease (PD) affects up to 10% of men, with an adverse impact on normal sexual function and overall well-being. ED can also be the first sign of other underlying disease. The office-based evaluation of ED and PD is the first step in the management of these devastating conditions of men's health. New and exciting nonsurgical therapies are now available to help treat these conditions and restore sexual function and quality of life.

Korean Society for Sexual Medicine and Andrology (KSSMA) Guideline on Erectile Dysfunction

In February 2011, the Korean Society for Sexual Medicine and Andrology (KSSMA) realized the necessity of developing a guideline on erectile dysfunction (ED) appropriate for the local context, and established a committee for the development of a guideline on ED. As many international guidelines based on objective evidence are available, the committee decided to adapt these guidelines for local needs instead of developing a new guideline. Considering the extensive research activities on ED in Korea, data with a high level of evidence among those reported by Korean researchers have been collected and included in the guideline development process. The latest KSSMA guideline on ED has been developed for urologists. The KSSMA hopes that this guideline will help urologists in clinical practice.

Corpus cavernosum electromyography: could it be a parameter to predict ageing?

In this study, we investigated whether electromyography of corpus cavernosum (CC-EMG) results vary with age and whether CC-EMG could be a parameter to predict ageing of cavernous smooth muscle. Recordings of electrical activity of corpus cavernosum (EACC) were retrospectively investigated in 134 patients with erectile dysfunction. Penile colour Doppler ultrasonography and cavernosometry were also performed for all of the patients. The total number and duration of EACC and amplitudes between positive and negative peaks were compared between the flask state for 10 min and after intracavernosal papaverine injection. The mean age of the 47 patients in group 1 was 35.2 ± 6.3 years (range, 23-44), the mean age of the 45 patients in group 2 was 51.1 ± 3.1 years (range, 45-56) and the mean age of the 42 patients in group 3 was 61.8 ± 4.6 years (range, 57-77). Total IIEF-5 score was 7.6 ± 2.1 in group 1, 7.9 ± 2.4 in group 2 and 7.9 ± 2.1 in group 3. There were no statistically significant differences among the groups regarding electrical potential frequencies, durations and amplitudes of electromyographic recordings.

CONCLUSION

We do not think that CC-EMG findings could be used efficiently as a predictor of ageing.

Depression in newly diagnosed type 2 diabetes

OBJECTIVE

To investigate the incidence of depression in newly diagnosed type 2 diabetes.

MATERIALS AND METHODS

One hundred newly diagnosed (4 - 12 weeks) T2DM participants were evaluated for depressive symptoms by using the Self-Rating Depression Scale (SDS). Blood glucose (HBA1C), urinary albumin, BMI, and blood pressure were measured. Sexual function was evaluated by a self-score on IIEF-5 Questionnaires in male participants below 60 years of age.

RESULTS

Twenty-eight (28%) of these had depressive scores, 18 (18%) had mild scores, six (6%) had moderate scores, and four had (4%) severe ones. In those who took oral medication, the percentage of depression was 18.5% (10/54) and in those who were treated by insulin the percentage was 39.1% (18/46). The levels of fasting blood glucose (FBG), HBA1c, and urinary albumin were higher in those with depression. The SDS score was negatively correlated with age and annual household income (r = 0.151,0.139, P < 0.05); 17% of the (8/48) males below 60 years of age was diagnosed with erectile dysfunction (ED) by II EF-5score < 20 and the severity of depressive symptoms was negatively correlated with II EF-5score (r = 0.131, P < 0.05).

CONCLUSION

These findings indicated that depressive symptoms are common in newly diagnosed type 2 diabetics. A variety of factors could be influencing the severity of depressive symptoms.

ELECTROCAVERNOSOGRAM IN ERECTILE DYSFUNCTION: A DIAGNOSTIC TOOL

Corpora cavernosa (CC) evoke electric waves that appear to be of diagnostic significance in evaluation of erectile dysfunction (ED). We investigated the hypothesis that electrocavernosography (ECG) exhibits different patterns in the various types of ED: neurogenic, vasculogenic, and psychogenic. Electrocavernosography was performed in the flaccid phase in 16 neurogenic, 28 vasculogenic (15 arteriogenic, 13 venogenic), and 24 psychogenic patients with ED, and in 15 healthy volunteers (controls). Two needle electrodes were introduced into the CC and the EMG activity was recorded in each of the 2 CCs of the same subject. Two 20 minute recording sessions were performed for each subject. The controls recorded slow waves (SWs) with regular rhythm and identical frequency, amplitude and conduction velocity from the 2 electrodes of the same subject. Random action potentials (APs) were superimposed on or followed the SWs. The ECG in the neurogenic ED recorded no waves in 14/16 patients and occasional irregular waves in 2. The SWs of the arteriogenic ED had irregular rhythm and variable and low parameters compared to those of the controls. The ECG of the patients with venogenic ED was similar to that of the controls, while the ECG of the psychogenic ED exhibited SWs with irregular rhythm and higher parameters than the controls. The study has revealed various ECG patterns in ED: "silent" in neurogenic. "bradyarrhythmic" in arteriogenic, "normal" in venogenic, and "overactive" in psychogenic ED. We suggest that electrocavernosography has the potential to function as an investigative tool in diagnosing the type of ED provided further studies are performed to verify the described findings.

Role of phosphodiesterase 5 in synaptic plasticity and memory

Phosphodiesterases (PDEs) are enzymes that break down the phosphodiesteric bond of the cyclic nucleotides, cAMP and cGMP, second messengers that regulate many biological processes. PDEs participate in the regulation of signal transduction by means of a fine regulation of cyclic nucleotides so that the response to cell stimuli is both specific and activates the correct third messengers. Several PDE inhibitors have been developed and used as therapeutic agents because they increase cyclic nucleotide levels by blocking the PDE function. In particular, sildenafil, an inhibitor of PDE5, has been mainly used in the treatment of erectile dysfunction but is now also utilized against pulmonary hypertension. This review examines the physiological role of PDE5 in synaptic plasticity and memory and the use of PDE5 inhibitors as possible therapeutic agents against disorders of the central nervous system (CNS).

Interstitial cells of Cajal in erectile dysfunction

The corpora cavernosa (CC) evokes electric activity. Slow waves (SWs) appear to originate from interstitial cells of Cajal (ICCs), which seem to control the activity of the smooth muscle cells (SMC). The ICCs were demonstrated to exist in the CC. We investigated the hypothesis that the ICC distribution differs with each of the various ED types. The study comprised 62 men with ED: 16 neurogenic (NGED), 15 arteriogenic (AGED), 11 venogenic (VGED) and 22 psychogenic (PGED). 15 volunteers with normal erections acted as controls. The patients underwent a complete diagnostic evaluation. A biopsy of 3 x 3 mm from the CC was subjected to C-kit immunohistochemistry examination. Specificity control of the antisera consisted of incubation of the tissue with normal rabbit serum substituted for the primary antiserum. C-kit positive stellate-appearing cells resembling those of ICC were detected in the controls. The branches were either laterally located (multipolar) or lying at each pole (bipolar). They were distinguishable from the SMC, which were C-kit negative. ICC were detected in all specimens from patients with NGED and VGED, absent in 13/15 with AGED and scanty in PGED. ICC distribution was different in the various types of ED. It is suggested that this distribution interferes with SW discharge and the control of SMC activity with a resulting ED.

The Effect of FK1706 on Erectile Function Following Bilateral Cavernous Nerve Crush Injury in a Rat Model

PURPOSE

We investigated the neurotrophic effect of FK1706 on erectile recovery following bilateral cavernous nerve crush injury in a rat model.

MATERIALS AND METHODS

A total of 28 male Sprague-Dawley rats were randomly divided into 4 equal groups. Seven animals underwent sham operation and subcutaneous vehicle injection, whereas 21 underwent bilateral cavernous nerve crush injury followed by vehicle injection alone, or by low (0.1 mg/kg) or high (1.0 mg/kg) dose FK1706 treatment. Injections were continued 5 days weekly for 8 weeks. Erectile function was then assessed by cavernous nerve electrostimulation and penile tissue was evaluated immunohistochemically.

RESULTS

No erectile dysfunction was identified in the sham treated group (mean maximal intracavernous pressure +/- SEM 106.8 +/- 6.4 cm H(2)O), whereas nerve injury significantly decreased ICP to 17.9 +/- 7.0 cm H(2)O. FK1706 facilitated neural and erectile recovery in a concentration dependent manner with a mean ICP in the high dose FK treatment group of 80.1 +/- 7.8 cm H(2)O compared with 44.1 +/- 12.9 cm H(2)O in the low dose group. Similar stepwise findings were observed using mean area under the curve data. Sham treated animals showed regular axon sizes and shapes with homogenous GAP-43 and neurofilament staining, whereas injured axons showed irregular shapes, sizes and staining patterns. FK1706 treatment restored axon shape and staining patterns. Injury significantly decreased nicotinamide adenine dinucleotide phosphate staining and FK1706 treatment showed a nonsignificant trend toward increased staining.

CONCLUSIONS

Bilateral cavernous nerve crush causes reproducible erectile dysfunction, consistent with prior experiments. High dose subcutaneous FK1706 therapy promotes significant neuroregeneration and erectile function recovery.

The hypoactive corpora cavernosa with degenerative erectile dysfunction: a new syndrome

BACKGROUND

In a group of 22 patients with erectile dysfunction, vasculogenic, neurogenic, endocrinologic or psychogenic investigations failed to find a cause for their erectile dysfunction. The electro-cavernosograms of these patients recorded a diminished activity. We investigated the hypothesis that diminished corpus cavernosum electromyography activity was the cause of erectile dysfunction in these patients.

METHODS

The study comprised the above mentioned 22 patients (study group, 43.8 +/- 5.9 SD years) and 15 healthy volunteers (control group, 41.8 +/- 5.1 SD years). The electro-cavernosograms were recorded in the flaccid, erectile and detumescent phases by 2 electrodes inserted into the corpus cavernosum.

RESULTS

The electro-cavernosogram of the healthy volunteers registered in the flaccid phase regular slow waves and random action potentials. The wave variables declined significantly in the erectile phase (p < 0.01). In the study group, the slow wave variables in the flaccid phase exhibited a significant decrease (p < 0.05) compared to the healthy volunteers, and the rhythm was irregular. Erection did not occur with sildenafil administration or intracavernosal papaverine injection, and penile implant was performed. Biopsy examination showed degenerated muscle fibers, and fragmented collagen and elastic fibers with areas of fibrosis.

CONCLUSION

A novel concept of the cause of erectile dysfunction was presented. Corpora cavernosa showed degenerative changes on histopathologic examination and exhibited diminished electromyography activity. They did not respond to sildenafil administration or intracavernosal papaverine injection. Penile implants were the only treatment. The condition is given the name 'hypoactive corpus cavernosum'. The cause of corpus cavernosum degenerative changes needs further study.

Epimedium brevicornum Maxim extract relaxes rabbit corpus cavernosum through multitargets on nitric oxide/cyclic guanosine monophosphate signaling pathway

Epimedium brevicornum Maxim (EbM) has been reputed to have sexual stimulation effects on males. The study is aimed to test the hypothesis that EbM extracts relaxed the corpus cavernosum (CC) smooth muscle through activation of multitargets on nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) signaling pathway. Water extract of EbM and its subfraction (EP-20) were prepared and standardized by high-performance liquid chromatography. Isolated rabbit CC strips were mounted in organ baths and isometric tension was recorded in the presence or absence of specific inhibitors related to NO/cGMP signaling such as L-N(G)-nitro-arginine methyl ester (L-NAME), 1H-[1,2,4]oxadiazolo-[4,3-a] quinoxalin-1-one (ODQ, a guanylyl cyclase inhibitor) or phosphodiesterase 5 (PDE 5) inhibitors. cGMP level was determined in EP-20-treated CC strips. The results showed that EP-20 enriched the content of L-arginine in the process of purification and relaxed the CC smooth muscle precontracted with phenylephrine (PE, 1 microM) in a concentration-dependent manner. Besides, EP-20 increased the amount of cGMP production in rabbit CC tissues. Coincubation with EP-20 and L-NAME or ODQ significantly decreased EP-20-induced relaxation whereas EP-20 increased sodium nitroprusside-induced relaxation in PE-precontracted CC strips. Besides, EP-20 increased the potency and the duration of the relaxation effects caused by electrical field stimulation. Finally, EP-20 could potentiate PDE 5 inhibitors in relaxation of PE-precontracted CC strips. We concluded that extract of EbM relax the CC smooth muscle through multitargets in NO/cGMP/PDE 5 pathway and might bring into perspective the treatment strategy for those patients with erectile dysfunction.

Effect of neonatal circumcision on penile neurologic sensation

OBJECTIVES

To evaluate penile sensory thresholds in neonatally circumcised and uncircumcised men.

METHODS

We evaluated 125 patients, 62 uncircumcised men and 63 neonatally circumcised men. All patients completed the Erectile Function domain of the International Index of Erectile Function questionnaire. Of the 125 patients, 29 (International Index of Erectile Function score of between 25 and 30) were placed in the functional group, and 96 in the dysfunctional group. The patients were tested on the dorsal midline glans of the penis (foreskin retracted). Quantitative somatosensory testing was performed and included vibration, pressure, spatial perception, and warm and cold thermal thresholds.

RESULTS

In the functional group, t-test analysis demonstrated a significant (P <0.001) difference, with worse vibration and better pressure sensation for uncircumcised men. When controlling for age, hypertension, and diabetes, all t-test significance was lost. In the dysfunctional group, circumcised men (49 +/- 16 years) were significantly younger (P <0.01) than uncircumcised men (56 +/- 13 years). For the dysfunctional group, t-test analysis also demonstrated worse vibration sensation for uncircumcised men (P <0.01). Again, when controlling for age, hypertension, and diabetes, all t-test significance was lost.

CONCLUSIONS

We present a comparative analysis of uncircumcised and circumcised men using a battery of quantitative somatosensory tests that evaluate the spectrum of small to large axon nerve fiber function. Our study controlled for factors, including age, erectile function status, diabetes, and hypertension, that have been shown to alter neurologic testing. In our study of neonatally circumcised men, we demonstrated that circumcision status does not significantly alter the quantitative somatosensory testing results at the glans penis.

Clinical Evaluation of Erectile Dysfunction in the Era of PDE-5 Inhibitors

Erectile dysfunction (ED) is a common disorder that has gained attention since the introduction of relatively safe treatment with phosphodiesterase-5 inhibitors. ED is a multi-factorial disorder and a common presentation for several systemic illnesses,particularly vascular occlusive diseases. The clinical evaluation of ED should be thorough and systematic, with attention to the appropriate use of sexual symptom questionnaires and symptom scales, detailed medical and sexual history, physical examination,and basic screening laboratory tests. Patients should be referred for specialized evaluations when appropriate. The clinician must be familiar with the pathophysiologic mechanisms of ED, its associations with other systemic diseases, the indications for specialist referrals, and the role of specialized testing to diagnose and treat this disorder effectively.

TRANSCUTANEOUS ELECTROCAVERNOSOGRAPHY: A TOOL FOR RECORDING THE ELECTROMYOGRAPHIC ACTIVITY OF THE CORPORA CAVERNOSA

PURPOSE

The electric activity of the corpora cavernosa (CC) is recorded by needle electrodes introduced into the CC. We investigated the hypothesis that transcutaneous electrocavernosography (ECG) would register electric waves similar to those recorded by the needle ECG but noninvasively.

MATERIALS AND METHODS

The ECG was recorded transcutaneously in 35 healthy volunteers (mean age 37.6 +/- 4.8 SD years). Two silver-silver chloride electrodes were applied on the dorsum of the penis over 1 of the CC. A reference electrode was applied to the thigh. Intracavernosal ECG using 2 needle electrodes introduced into the CC was performed in the same subjects. At least two 20 minutes sessions were recorded for each subject.

RESULTS

Slow waves (SWs) were registered transcutaneously. The waves from the 2 electrodes in each individual had the same frequency, amplitude and conduction velocity. They had a regular rhythm and were reproducible. The SWs were followed or superimposed by action potentials which occurred randomly. The transcutaneously recorded SWs were confirmed by the intracavernous route. Both routes had similar ECG recordings.

CONCLUSIONS

The study demonstrated that the transcutaneous ECG recorded electric waves similar to those registered by the intracavernosal route. The transcutaneous ECG is simple, easy, non-invasive, and may be included as an investigative tool in the diagnosis of erectile dysfunction.

The additive erectile recovery effect of brain-derived neurotrophic factor combined with vascular endothelial growth factor in a rat model of neurogenic impotence

OBJECTIVE

To test the hypothesis that combined intracavernosal injection with vascular endothelial growth factor (VEGF) with adeno-associated virus-mediated brain-derived neurotrophic factor (AAV-BDNF) synergistically facilitates the neural regeneration and erectile function after cavernosal nerve injury.

MATERIALS AND METHODS

Forty Sprague-Dawley male rats were randomly divided into five equal groups: eight had a sham operation while 32 had bilateral cavernosal nerve freezing followed by an immediate intracavernosal injection with either phosphate-buffered saline (PBS), VEGF, AAV-BDNF, or AAV-BDNF + VEGF. Erectile function was assessed by cavernosal nerve electrostimulation at 3 months, and samples of the major pelvic ganglia and penile tissue were evaluated histologically.

RESULTS

In this animal model of impotence from nerve injury, the recovery of erectile function was greatest in those receiving AAV-BDNF + VEGF; the mean (sd) maximal intracavernosal pressure in this group was 87.2 (20.78) cmH2O, compared with 37.3 (11.39) for VEGF alone and 49.8 (29.58) for AAV-BDNF alone. No erectile dysfunction was identified in the sham group, with a pressure of 100.7 (22.70) cmH2O, while all treatment groups significantly outperformed the PBS (control) group, at 29.3 (13.52) cmH2O. Furthermore, all animals receiving monotherapy or combined treatment had more NADPH-diaphorase-positive nerve fibres than controls but less than in the sham group.

CONCLUSION

Bilateral cavernosal nerve freezing causes erectile dysfunction with accompanying neurological changes. Intracavernosal injection with either VEGF or AAV-BDNF alone enhances nerve regeneration, with combined therapy (VEGF and AAV-BDNF) promoting neural and erectile recovery additively.

Overactive corpus cavernosum: a novel cause of erectile dysfunction

Our recording of the electromyographic (EMG) activity of the corpus cavernosum (CC) in 59 patients with erectile dysfunction (ED) revealed 18 patients who had elevated electric activity, which presumably points to heightened tone of the CC smooth muscles. We investigated the hypothesis that this elevated EMG activity and muscular tone of the CC could be the cause of ED. The study comprised the said 18 subjects with the hypertonic CC muscles as study group (42.6 +/- 5.3 SD years), 15 healthy volunteers (41.8 +/- 5.1 SD years) and 15 patients (41.6 +/- 5.5 SD years) with ED who had not recorded elevated tone of the CC muscles as control group. The EMG activity was registered in the flaccid, erectile and detumescent phases by two electrodes inserted into the CC. Electrocavernosography (ECG) of healthy volunteers recorded in the flaccid phase showed regular slow waves (SW) and random action potentials (APs). The wave variables declined significantly in the erection phase (P < 0.01). In the study group, the SW variables in the flaccid phase increased significantly (P < 0.05) compared with the healthy volunteers and the rhythm was irregular. Erection did not occur with sildenafil but with intracavernosal injection of papaverine, which led to decline of the SW variables (P < 0.05). The control ED group exhibited in the flaccid phase diminished SW variables (P < 0.05) compared with the healthy volunteers. On erection with sildenafil administration, the SW variables showed significant reduction (P < 0.05). CC hypertonicity or 'overactive CC' was identified as a possible cause of ED. An elevated EMG activity of the CC muscle fibres in the flaccid phase presumably denotes hypertonicity of these fibres and their failure to relax to effect erection. The cause of elevated CCEMG activity and presumed muscle hypertonicity is unknown and could be functional or organic. Erection was produced by intracavernosus injection of papaverine and not by sildenafil. This condition of 'overactive CC' should be considered in the diagnosis of ED. However, further studies in the pathogenesis of the condition are warranted.

Specific aspects of erectile function in urology/andrology

The urologist/andrologist is the specialist responsible for diagnosis and treatment of health problems related to the genitourinary tract, and his or her participation in comprehensive care for a patient with erectile dysfunction (ED) is fundamental and often indispensable. The urologists/andrologists should characterize the origin of ED because of their knowledge and familiarity of all diagnostic tests and second- and third-line therapy. The origin of ED is important to determine for various reasons, such as young people suitable for etiologic treatment, medicolegal reasons, or patients' wishes for a better understanding of their condition. A review of the diagnostic tests available as well as indications for second- and third-line therapy is presented. The close relationship between ED and urological disorders, such as benign prostatic hyperplasia, prostate cancer and their treatments, and renal failure, in association with penile conditions like Peyronie's disease, priapism, and possible androgen deficiency in men older than 50 years, places the urologist at the center of integrated treatment of male ED.

Investigations in erectile dysfunction

PURPOSE OF REVIEW

This is an update of recent developments in the investigation of erectile dysfunction in the period since March 2002.

RECENT FINDINGS

Three developments in the field of medical sexology redirected the approach towards the investigation of erectile dysfunction. First, the emergence of oral pharmacological therapy; second, the notion that sexual relationship issues have an important impact on the successful outcome of pharmacological therapy; and finally, the concept that erectile dysfunction is often a sequel or even a sentinel of cardiovascular disease. Consequently, the current evaluation of men with erectile dysfunction may be divided into two steps: a basic diagnostic evaluation for the majority of men, and specific diagnostic procedures for a small minority. The basic evaluation is aimed at the identification of the underlying pathological condition and erectile dysfunction-associated risk factors. Such screening may diagnose reversible causes of erectile dysfunction and also unmask medical and psychological conditions that manifest with erectile dysfunction. The basic evaluation consists of a comprehensive medical, sexual and psychosocial history and a physical examination. Patients who have failed first-line treatment or complicated cases qualify for specific diagnostic procedures, traditionally performed by urologists.

SUMMARY

Current research into the investigation of erectile dysfunction emphasizes the notion that erectile dysfunction is often a result of an interplay between medical and psychosexual conditions. Recognition of the underlying conditions and an estimation of their relative contribution to the patient's and his partner's sexual problem are key issues in the current evaluation of the man with erectile dysfunction.

Therapies for neurologic erectile dysfunction

A subset of men with erectile dysfunction have an underlying neurologic or neurodegenerative condition which directly causes their impairment. The authors briefly discuss the interplay of the CNS, peripheral nervous system and corporal bodies of the penis integral to normal erectile function and how these interactions are disrupted in the setting of various neurologic conditions. Effective therapies for these patients exist in a variety of different forms to include oral or injectable drugs and even surgery. Future treatment strategies will focus on the improvement of existing therapies as well as the invention of new long-term therapeutic options.

Neuroprotection and nerve grafts in the treatment of neurogenic erectile dysfunction

PURPOSE

The rationale for protecting the nerve supply of the penis derives mainly from the fact that neurological injury or disease states involving this organ commonly result in erectile dysfunction. Novel directions in the management of neurogenic erectile dysfunction that pertain specifically to sustaining penile neuronal function are described.

MATERIALS AND METHODS

The review constitutes a summary of neuroprotective strategies for penile erection that are under investigation at the basic science level or have been brought to clinical practice. The basic exercise consisted primarily of a literature search using the National Library of Medicine PubMed Services, with references made to such keywords as nerve grafts, nerve growth factors, neuroprotection and nerve regeneration.

RESULTS

Primary advances in this field have centered on repairing structural defects and restoring the functional integrity of the cavernous nerves of the penis. In the former autologous nerve conduits, such as sural nerve grafts, have been explored and used prominently in the context of radical prostatectomy. In the latter diverse neurotrophic treatments have been investigated, with progress mostly limited to animal models of cavernous nerve injury. Basic concepts and ongoing developments in the neurobiology of axonal regeneration were identified as being applicable to this area of neurourology.

CONCLUSIONS

Because neurogenic origins represent a leading categorical cause of erectile dysfunction, the importance of developing and applying treatment approaches to alleviate neuropathic effects on the erectile tissue of the penis is certain. Medical and surgical innovations for preserving and reconstituting the functional nerve supply of the penis offer great promise in the management of erectile dysfunction.

Quantitative somatosensory testing of the penis: optimizing the clinical neurological examination

PURPOSE

Quantitative somatosensory testing, including vibration, pressure, spatial perception and thermal thresholds of the penis, has demonstrated neuropathy in patients with a history of erectile dysfunction of all etiologies. We evaluated which measurement of neurological function of the penis was best at predicting erectile dysfunction and examined the impact of location on the penis for quantitative somatosensory testing measurements.

MATERIALS AND METHODS

A total of 107 patients were evaluated. All patients were required to complete the erectile function domain of the International Index of Erectile Function (IIEF) questionnaire, of whom 24 had no complaints of erectile dysfunction and scored within the "normal" range on the IIEF. Patients were subsequently tested on ventral middle penile shaft, proximal dorsal midline penile shaft and glans penis (with foreskin retracted) for vibration, pressure, spatial perception, and warm and cold thermal thresholds.

RESULTS

Mixed models repeated measures analysis of variance controlling for age, diabetes and hypertension revealed that method of measurement (quantitative somatosensory testing) was predictive of IIEF score (F = 209, df = 4,1315, p <0.001), while site of measurement on the penis was not. To determine the best method of measurement, we used hierarchical regression, which revealed that warm temperature was the best predictor of erectile dysfunction with pseudo R(2) = 0.19, p <0.0007. There was no significant improvement in predicting erectile dysfunction when another test was added. Using 37C and greater as the warm thermal threshold yielded a sensitivity of 88.5%, specificity 70.0% and positive predictive value 85.5%.

CONCLUSIONS

Quantitative somatosensory testing using warm thermal threshold measurements taken at the glans penis can be used alone to assess the neurological status of the penis. Warm thermal thresholds alone offer a quick, noninvasive accurate method of evaluating penile neuropathy in an office setting.

The neuropathy of erectile dysfunction

These studies were intended to explore the relationship between autonomic neuropathy and erectile dysfunction (ED). Sensory thresholds reflecting the integrity of both large diameter, myelinated neurons (ie pressure, touch, vibration) and small diameter axons (ie hot and cold thermal sensation) were determined on the penis and finger. Data were compared across subjects with and without ED, controlling for age, hypertension and diabetes. The correlation of specific thresholds scores and IIEF values were also examined. Seventy-three patients who visited the academic urology clinics at Montefiore hospital were evaluated. All patients were required to complete the erectile function domain of the International Index of Erectile Function (IIEF) questionnaire: 20 subjects had no complaints of ED and scored within the 'normal' range on the IIEF. Patients were subsequently tested on their index finger and glans penis for vibration (Biothesiometer), pressure (Semmes-Weinstein monofilaments), spatial perception (Tactile Circumferential Discriminator), and warm and cold thermal thresholds (Physitemp NTE-2). Sensation of the glans penis, as defined by the examined sensory thresholds, was significantly diminished in patients with ED and these differences remained significant when controlling for age, diabetes and hypertension. In contrast, thresholds on the index finger were equivalent in the ED and non-ED groups. Threshold and IIEF scores were highly correlated, consistent with an association between diminished sensation and decreasing IIEF score (worse erectile functioning). These relations also remained significant when controlling for age, diabetes and hypertension. The findings demonstrate dysfunction of large and small diameter nerve fibers in patients with ED of all etiologies. Further, the neurophysiologic measures validate the use of the IIEF as an index of ED, as objective findings of sensory neuropathy were highly correlated with worse IIEF scores. The sensory threshold methods utilized represent novel, non-invasive and relatively simple procedures, which can be used in a longitudinal fashion to assess a patient's neurological response to therapies.

[Erectile dysfunction]

In Spain, based on the IIEF, 19% of males between 25 and 70 years old present some degree of erectile dysfunction (ED). Therefore, around 2,000,000 Spanish men present this condition and could require medical attention for it. Here, we present an up-date of the most important aspects of erectile dysfunction (pathophysiology, diagnosis and treatment). We review, in detail, the oral treatments and future drugs that are presently in the premarketing experimental phase. Diagnostic and therapeutic management of the patient with erectile dysfunction should be individualized, taking into account the goals of each patient. It is highly recommendable to carry out a basic assessment (comprehensive clinical history, physical examination, recommended lab testing). If previously undiagnosed diseases are discovered (diabetes, arteriosclerosis, etc.) these should be treated and modifiable risk factors should be corrected. There are numerous therapeutic options for the treatment of erectile dysfunction. Replacement therapy with testosterone should only be used in males with ED and low levels of this hormone, under medical supervision. At present, first line treatment consists of the administration of oral drugs (sildenafil, apomorphine). There are two new PDE 5 inhibitors (tadalafil and vardenafil) that will be released on the market 2003, which will provide better selectivity. Moreover, several drugs for oral administration are in the initial phases of research that will facilitate erection via a direct penile action. When oral drugs are contraindicated, are not effective or when they are unpopular with the patient, the second line of treatment is intracavernous injection. Prostaglandin E1 is the initial drug of choice in patients using intracavernous autoinjection for the first time and has a high efficacy. Implantation of a penis prosthesis and penile revascularisation are appropriate for highly selected patients. Psychotherapy can be an option for men with ED of psychogenic origin, either as a monotherapy or combined with sildenafil or apomorphine.

Erectile dysfunction and diabetes

Erectile dysfunction (ED) has been the most neglected complication of diabetes. It is a common abnormality that affects more than 20 million American men. The prevalence of ED in the general population between the ages of 40 to 70 years is 52%. In men with diabetes, it ranges from 35% to 75%, and occurs at an earlier age. There have been several advances in the understanding of the physiologic and biochemical mechanisms controlling penile erections. Improved techniques in diagnoses and treatment of impotence have given the male with diabetes some hope in the management of this prevalent and emotionally disturbing complication.

Neurogenic erectile dysfunction

Penile erection is a neurovascular event modulated by psyche and hormones. Erectile dysfunction (ED) has been classified as psychogenic, arteriogenic, neurogenic, endocrinologic, and cavernosal, based on the organs that are involved in penile erection. Among these types, neurogenic ED may be the most common, probably because a deficiency of neurotransmitters is the final common pathway in many diseases and conditions. This review discusses the physiology, pathophysiology, diagnosis, and treatment of erectile function and dysfunction, as well as strategies for future research.