Phosphodiesterase Type 5 Inhibitors in Postprostatectomy Erectile Dysfunction: A Critical Analysis of the Basic Science Rationale and Clinical Application

Low-intensity pulsed ultrasound ameliorates erectile dysfunction induced by bilateral cavernous nerve injury through enhancing Schwann cell-mediated cavernous nerve regeneration

BACKGROUND

Cavernous nerve injury-induced erectile dysfunction caused by pelvic surgery or trauma is refractory to conventional medications and required an alternative treatment. Low-intensity pulsed ultrasound is a noninvasive mechanical therapy that promotes nerve regeneration.

OBJECTIVES

To investigate the therapeutic effect and potential mechanism of low-intensity pulsed ultrasound in the treatment of neurogenic erectile dysfunction.

MATERIALS AND METHODS

Thirty rats were randomly divided into the sham-operated group, bilateral cavernous nerve injury group, and bilateral cavernous nerve injury + low-intensity pulsed ultrasound group. The erectile function was assessed 3 weeks after daily low-intensity pulsed ultrasound treatment. The penile tissues and cavernous nerve tissues were harvested and subjected to histologic analysis. Primary Schwann cells and explants were extracted from adult rats. The effects of low-intensity pulsed ultrasound on proliferation, migration, and nerve growth factor expression of Schwann cells and axonal elongation were examined in vitro. RNA sequencing and western blot assay were applied to predict and verify the molecular mechanism of low-intensity pulsed ultrasound-induced Schwann cell activation.

RESULTS

Our study showed that low-intensity pulsed ultrasound promoted Schwann cells proliferation, migration, and neurotrophic factor nerve growth factor expression. Meanwhile, low-intensity pulsed ultrasound exhibits a stronger ability to enhance Schwann cells-mediated neurite outgrowth of major pelvic ganglion neurons and major pelvic ganglion/cavernous nerve explants in vitro. In vivo experiments demonstrated that the erectile function of the rats in the bilateral cavernous nerve injury + low-intensity pulsed ultrasound group was significantly higher than those in the bilateral cavernous nerve injury groups. Moreover, the expression levels of smooth muscle and cavernous endothelium also increased significantly in the bilateral cavernous nerve injury + low-intensity pulsed ultrasound group. In addition, we observed the higher density and number of cavernous nerve regenerating axons in the bilateral cavernous nerve injury + low-intensity pulsed ultrasound group, indicating that low-intensity pulsed ultrasound promotes axonal regeneration following cavernous nerve injury in vivo. RNA sequencing analysis and bioinformatic analysis suggested that low-intensity pulsed ultrasound might trigger the activation of the PI3K/Akt pathway. Western blot assay confirmed that low-intensity pulsed ultrasound activated Schwann cells through TrkB/Akt/CREB signaling.

CONCLUSIONS

Low-intensity pulsed ultrasound promoted nerve regeneration and ameliorated erectile function by enhancing Schwann cells proliferation, migration, and neurotrophic factor nerve growth factor expression. The TrkB/Akt/CREB axis is the possible mechanism of low-intensity pulsed ultrasound-mediated Schwann cell activation. Low-intensity pulsed ultrasound-based therapy could be a novel potential treatment strategy for cavernous nerve injury-induced neurogenic erectile dysfunction.

Implantation of skin-derived precursor Schwann cells improves erectile function in a bilateral cavernous nerve injury rat model

BACKGROUND

This study was conducted to investigate the therapeutic potential of the skin-derived precursor Schwann cells for the treatment of erectile dysfunction in a rat model of bilateral cavernous nerve injury.

RESULTS

The skin-derived precursor Schwann cells-treatment significantly restored erectile functions, accelerated the recovery of endothelial and smooth muscle tissues in the penis, and promoted nerve repair. The expression of p-Smad2/3 decreased after the treatment, which indicated significantly reduced fibrosis in the corpus cavernosum.

CONCLUSIONS

Implantation of skin-derived precursor Schwann cells is an effective therapeutic strategy for treating erectile dysfunction induced by bilateral cavernous nerve injury.

Established Immortalized Cavernous Endothelial Cells Improve Erectile Dysfunction in Rats with Cavernous Nerve Injury

The main cause of erectile dysfunction (ED) is the damage in penile cavernous endothelial cells (EC). Murine primary ECs have a limited growth potential, and the easy availability of murine ECs will facilitate the study of cavernous endothelial dysfunction in rats. This study was performed to establish immortalized rat penile cavernous ECs (rEC) and investigate how they could repair erectile dysfunction in rats with cavernous nerve injury (CNI). rEC was isolated enzymatically by collagenase digestion and were cultured. An amphotropic replication-incompetent retroviral vector encoding v-myc oncogene was used to transfect rEC for immortalization (vREC). Morphological and immunohistochemical properties of vREC were examined. Eight-week-old male Sprague-Dawley rats were divided into three groups of five rats each, including group 1 = sham operation, group 2 = bilateral CN injury, group 3 = vREC (1 × 106 cells) treatment after CNI. Erectile response was assessed at 2, 4 weeks after transplantation of vREC., Penile tissue were harvested at 4 weeks after transplantation and immune−histochemical examination was performed. vREC showed the expression of CD31, vWF, cell type-specific markers for EC by RT-PCR and flowcytometry. At 2, 4 weeks after transplantation, rats with CNI had significantly lower erectile function than control group (p < 0.05). The group transplanted with vREC showed higher erectile function than the group without vRECs (p < 0.05). vREC was established and repaired erectile dysfunction in rats with CNI. This cell line may be useful for studying mechanisms and drug screening of erectile dysfunction of rats.

Use of phosphodiesterase-5 inhibitors and the incidence of melanoma

INTRODUCTION

Recent evidence of a causal link between Phosphodiesterase-5-inhibitor (PDE-5i) use and melanoma has caused concern in PDE-5i use and was even addressed in the 2018 American Urological Association guideline on erectile dysfunction (ED). Given that several studies have affirmed this low probability but statistically significant association, one might expect a shift in melanoma diagnoses since PDE-5is were introduced in 1998. We sought to determine if the introduction of PDE-5i drugs for ED treatment increased incidence of melanoma.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to compare the incidence of melanoma diagnosis in American men between 1973 and 2015, providing over a decade of data before and after PDE-5i introduction in 1998. Interrupted time-series and logistic regression were used to assess this relationship.

RESULTS

Over 43 years, the SEER database has reported 292,166 cases of Melanoma, with males accounting for 53.7% of cases (Standard deviation [SD] 3%, Range 47.5-58.3%). After the introduction of PDE-5i, there was no proportional increase in melanoma diagnoses, in fact demonstrating a 2% lower incidence from prediction models (p < 0.05).

CONCLUSION

Our analysis of the SEER database demonstrates that the trend in incidence of melanoma has fallen in the era of PDE-5i use for ED. These findings may be of value in counseling patients anxious about the potential association between PDE-5i use and skin cancer; however, continued research analyzing individual-level risk are needed.

Improvement of erectile dysfunction using endothelial progenitor cells from fetal cerebral vasculature in the cavernous nerve injury of rats

BACKGROUND

Because of limited differentiation to endothelium from mesenchymal stem cells, it has been strongly recommended to use endothelial progenitor cells for the regeneration of the damaged endothelium of corpora cavernosa. This study was performed to investigate the immortalized human cerebral endothelial cells and their capability for repairing erectile dysfunction in a rat model of cavernous nerve injury. Circulating endothelial progenitor cells were isolated from human fetal brain vasculature at the periventricular region of telencephalic tissues. Over 95% of CD 31-positive cells were sorted and cultured for 10 days. Human cerebral endothelial progenitor cells were injected into the cavernosa of rats with cavernous nerve injury. Erectile response was then assessed. In in vivo assays, rats were divided into three groups: group 1, sham operation: group 2, bilateral cavernous nerve injury: and group 3, treatment with human cerebral endothelial cells after cavernous nerve injury.

RESULTS

Established immortalized circulating endothelial progenitor cells showed expression of human telomerase reverse transcriptase transcript by RT-PCR. They also showed the expression of vascular endothelial growth factor, von Willebrand factor, vascular endothelial growth factor receptor, and CD31, cell type-specific markers for endothelial cells by RT-PCR. In in vitro angiogenesis assays, they demonstrated tube formation that suggested morphological properties of endothelial progenitor cells. In in vivo assays, impaired erectile function of rat with cavernous nerve injury recovered at 2, 4, and 12 weeks after transplantation of human cerebral endothelial cells into the cavernosa.

CONCLUSIONS

Telomerase reverse transcriptase-circulating endothelial progenitor cells from fetal brain vasculature could repair erectile dysfunction of rats with cavernous nerve injury.

Comparison of the therapeutic effects of human umbilical cord blood-derived mesenchymal stem cells and adipose-derived stem cells on erectile dysfunction in a rat model of bilateral cavernous nerve injury

Background: Cavernous nerve injury (CNI) is the leading cause of erectile dysfunction (ED) after radical prostatectomy and pelvic fracture. Transplantation of human adipose-derived stem cells (ASCs) has been widely used to restore erectile function in CNI-ED rats and patients. Umbilical cord blood-derived MSCs (CBMSCs) are similarly low immunogenic but much primitive compared to ASCs and more promising in large-scale commercial applications due to the extensive establishment of cord blood banks. However, whether CBMSCs and ASCs have differential therapeutic efficacy on CNI-ED and the underlying mechanisms are still not clear.

Materials and methods: A bilateral cavernous nerve injury (BCNI) rat model was established by crushing the bilateral cavernous nerves. After crushing, ASCs and CBMSCs were intracavernously injected immediately. Erectile function, Masson staining, and immunofluorescence analyses of penile tissues were assessed at 4 and 12 weeks. PKH-26-labeled ASCs or CBMSCs were intracavernously injected to determine the presence and differentiation of ASCs or CBMSCs in the penis 3 days after injection. In vitro experiments including intracellular ROS detection, mitochondrial membrane potential assay, EdU cell proliferation staining, cell apoptosis assay, and protein chip assay were conducted to explore the underlying mechanism of CBMSC treatment compared with ASC treatment.

Results: CBMSC injection significantly restored erectile function, rescued the loss of cavernous corporal smooth muscles, and increased the ratio of smooth muscle to collagen. PKH-26-labeled CBMSCs or ASCs did not colocalize with endothelial cells or smooth muscle cells in the corpus cavernosum. Moreover, the conditioned medium (CM) of CBMSCs could significantly inhibit the oxidative stress and elevate the mitochondria membrane potential and proliferation of Schwann cells. Better therapeutic effects were observed in the CBMSC group than the ASC group both in vivo and in vitro. In addition, the content of neurotrophic factors and matrix metalloproteinases in CBMSC-CM, especially NT4, VEGF, MMP1, and MMP3 was significantly higher than that of ASC-CM.

Conclusion: Intracavernous injection of CBMSCs exhibited a better erectile function restoration than that of ASCs in CNI-ED rats owing to richer secretory factors, which can promote nerve regeneration and reduce extracellular matrix deposition. CBMSC transplantation would be a promising therapeutic strategy for CNI-ED regeneration in the future.

Management of male sexual dysfunction after cancer treatment

BACKGROUND

With an increase in the number of cancer survivors each year, male sexual dysfunction becomes an important topic for discussion between patients and providers who treat cancer. The aim of this article is to review types and mechanisms of sexual dysfunction after cancer therapy and discuss treatment options.

METHODS

Contemporary concepts regarding male sexual dysfunction after cancer treatment are reviewed and translated for clinical utility.

FINDINGS

To optimize recovery of erectile capacity after erectile dysfunction causing cancer treatments, a penile rehabilitation protocol involving phosphodiesterase inhibitors, vacuum erection device, intra corporal injections, or a combination is likely to provide some degree of clinically significant benefit. Treating hypogonadism post cancer treatment depends on the type of cancer that has been treated and patient comorbidities. Anejaculation after cancer treatments is typically not successfully or reliably treated due to the mechanism and severity of sympathetic nerve injury. Semen cryopreservation prior to cancer treatments that may injure nerve fibers essential for the ejaculatory response is highly recommended.

CONCLUSION

Management of post cancer treatment sexual dysfunction requires identification of this problem and referral to a specialist if necessary. There are several management options available that can greatly enhance quality of life in this often overlooked aspect of post cancer treatment care.

Low-intensity Extracorporeal Shockwave Therapy for the Management of Postprostatectomy Erectile Dysfunction: A Systematic Review of the Literature

Context

Erectile dysfunction (ED) following radical prostatectomy is a concern for patients and their partners. Low-intensity extracorporeal shockwave therapy (LI-ESWT) can potentially enhance tissue repair and regeneration. The aim of the current study was to systematically review the literature to assess the role of LI-ESWT in the management of patients with postprostatectomy ED.

Evidence acquisition

Two authors independently performed a systematic search of the PubMed and Web of Science databases to identify all relevant articles. Non-English reports, case reports, reviews, letters, and editorials were excluded. Risk of bias was assessed according to the GRADE guidelines.

Evidence synthesis

Nine articles met the inclusion criteria and were included in the qualitative analysis. All the studies included were published between 2015 and 2022 and the majority of them compared phosphodiesterase type 5 inhibitors (PDE5Is) alone versus a combination of LI-ESWT and PDE5Is. Only three studies were randomized controlled trials (RCTs). In general, there is no standardized protocol for LI-ESWT for postprostatectomy ED. In comparisons of LI-ESWT + PDE5Is versus PDE5Is alone, some authors found a statistically significant improvement in erectile function with LI-ESWT + PDE5Is. The starting time for LI-ESWT differed among the studies, ranging from 3 d to 6 mo after surgery. The main limitations of the review are the scarcity of studies, small sample sizes, high risk of bias, and high heterogeneity among studies.

Conclusions

There is currently limited evidence on the use of LI-ESWT either alone or in combination with PDE5Is in penile rehabilitation protocols after prostatectomy. However, small clinical trials with short follow-up show that LI-ESWT could potentially play a role in the management of postprostatectomy ED in the future. Further RCTs with larger sample sizes are needed.

Patient summary

Despite limited reports in the literature, low-intensity shockwave therapy after removal of the prostate is a promising noninvasive treatment for dealing with erectile dysfunction after surgery.

Current trends in erectile rehabilitation after radical prostatectomy: Results from a worldwide survey

We aimed to analyse the current trend of erectile rehabilitation (ER) following radical prostatectomy (RP) using a dedicated survey. An online survey was developed between July and September 2020, aiming to evaluate the ER protocols after RP in daily practice among urologists, andrologists, sexual medicine specialists and residents. We investigated demographics data, type of RP performed, and type, schedule, timing and duration of ER protocols. In total, 518 responders from 52 countries completed the survey. Surgical techniques reported were: 38.9% open, 22.9% laparoscopic and 38.2% robot-assisted RP. 33% of the responders begin ER at the catheter removal, 22% 1 month after surgery and 15% before surgery. Phosphodiesterase inhibitors were the most used medication as first-line treatment (99.4%). Tadalafil 20 mg was the most prescribed, and used daily in 48.2% of the cases, and 2-3 times/week in 46%. Intra-cavernosal injection of prostaglandin E1 was the second most common prescribed monotherapy (67.9%) followed by the association of phosphodiesterase inhibitors and vacuum-erection device (29.6%). The duration of ER was <6 months in 16.2%, between 6 and 11 months in 39%, between 12 and 18 months in 31.9%, between 19-24 months in 9.2% and >24 months in 3.7%. This study showed that the approach to ER after RP was inhomogeneous. International guidelines are urgently needed to standardise ER protocols.

Cavernous Nerve Injury Resulted Erectile Dysfunction and Regeneration

Erectile dysfunction (ED) is an important cause of reduced quality of life for men and their partners. Recent studies have found that cavernous nerve injury (CNI) during prostate cancer surgery and other pelvic surgery results in medically induced CNIED in more than 80% of patients. The efficacy of first- and second-line treatment options for ED is poor. A great deal of research has been devoted to exploring new methods of neuroprotection and nerve regeneration to save erectile function in patients with CNIED, especially in patients with cavernous nerve injury after prostate cancer surgery. In addition, such as neuromodulatory proteins, proimmune ligands, gene therapy, stem cell therapy, and the current cutting-edge low-energy shock wave therapy have shown advantages in basic research and limited clinical studies. In the context of today's modern medicine, these new therapeutic techniques are expected to be new tools in the treatment of cavernous nerve injury erectile dysfunction. This article presents the main causes, mechanisms, and treatment of cavernous nerve injury erectile dysfunction and combines them with new treatment strategies.

MicroRNA-126 engineered muscle-derived stem cells attenuates cavernosa injury-induced erectile dysfunction in rats

BACKGROUND

Cavernosa injury is a common cause of organic erectile dysfunction (ED), which requires safe and effective treatments. In the present study, the therapeutic efficiency of muscle-derived stem cells (MDSCs) modified with microRNA-126 (miR-126) was determined in rats with cavernosa injury.

METHODS

MDSCs were transfected with miR-126 and then were transplanted into rats with cavernosa injury. Erectile function, vascular function (western blot and immunofluorescence), extraction, and detection of exosomes were then undertaken.

RESULTS

On the 28th day after transplantation, the highest value of intra-cavernous pressure (ICP)/mean arterial pressure (MAP) in rats of miRNA-126 group (0.84 ± 0.14) was observed (Control: 0.38 ± 0.07; MDSC: 0.54 ± 0.11, Vector: 0.60 ± 0.02; respectively). Treatment of miRNA-126-modified-MDSCs remarkably strengthened vascular structure, supported by hematoxylin-eosin staining. The expression of CD31, von Willebrand Factor and vascular endothelial factors were higher than those in other groups, indicating improved vascular function. In vitro mechanism studies showed that exosomes containing miR-126 isolated from MDSCs promoted angiogenesis and attenuated apoptosis of human umbilical venous endothelial cells. Finally, insulin receptor substrate 1 and Krüppel-like factor 10 were determined as the direct target genes of miR-126.

CONCLUSIONS

MiR-126 engineered MDSCs notably repaired cavernosa injury in rats via vascular reconstruction by directly targeting IRS1 and KLF10, in which the exosomes secreted by MDSCs played a critical role.

Improvement of damaged cavernosa followed by neuron-like differentiation at injured cavernous nerve after transplantation of stem cells seeded on the PLA nanofiber in rats with cavernous nerve injury

This study investigated the differentiation of transplanted transplanted mesenchymal stem cells MSCs into neuron-like cells, repair of erectile dysfunction (ED), and synergy of MSCs seeded to nanofibrous scaffolds with after transplantation around the injured cavernous nerve (CN) of rats. The synthesized polymer was electrospun in a rotating drum to prepare nanofiber meshes (NMs). Human MSCs were prepared and confirmed. Eight-week-old male Sprague-Dawley rats were divided into five groups of six each: group 1-sham operation; group 2-CN injury; group 3-MSCs treatment after CN injury; group 4-nanofibrous scaffold treatment after CN injury; and group 5-post-CN injury treatment combining a nanofibrous scaffold and MSCs (nano-MSCs). In the latter group, the damaged CN was instantly surrounded by an MSC-containing a nanofibrous scaffold in the aftermath of injury. Morphological analysis and immuno-histochemical staining in relation to nerves (Tuj1, NF, MAP2, MBP and peripherin), endothelium (vWF), smooth muscle (SMA), neurofilament (NF), and apoptosis (TUNEL) were performed. We evaluated the mean proportion expressed as a percentage of the ratio of muscle to collagen of penile cavernous smooth-muscle cells as well as the expression of cavernous SMA, NF, vWF, and TUNEL makers. Compared to the group free of CN injury, erectile function was markedly reduced in the group with CN injury at 2 and 4 weeks (p < 0.05). By contrast, compared to the sham operation group, erectile function was better in the group with MSC transplantation (p < 0.05). Similarly, by comparison to the group solely with hMSCs, erectile function was better in the group with nano-MSC transplantation (p < 0.05). Transplantation of MSCs demonstrated the neuronal differentiation. By contrast to MSCs on their own, neuronal differentiation was more significantly expressed in nano-MSCs. The mean proportion expressed as a percentage of the ratio of muscle to collagen of penile cavernous smooth-muscle cells, the expression of cavernous SMA, NF, vWF, and apoptosis improved in the cavernosum after transplantation. NMs showed synergy with MSCs for the repair of erectile dysfunction. Transplanted MSCs differentiated into neuron-like cells and repaired erectile dysfunction in the rats with CN injury. Transplanted MSCs increased the mean percentage of the collagen area of the caversnosum as well as the expression levels of cavernous neuronal, endothelial, smooth-muscle markers, and apoptosis.

Comparative study of different transplantation methods of adipose tissue-derived stem cells in the treatment of erectile dysfunction caused by cavernous nerve injury

We aimed to compare intracavernosal injection (ICI), tail vein injection (IV), and periprostatic injection (PPI) of adipose-derived stem cells (ADSCs) for their ability to improve erectile function in cavernous nerve injury-induced erectile dysfunction (CNIED) rats and to explore the possible mechanism. Eighty-four male SD rats were divided into the sham group (n = 6), BCNI group (bilateral CN crush injury, n = 6), PBS-ICI group (n = 6), PBS-IV group (n = 6), PBS-PPI group (n = 6), ADSC-ICI group (n = 18), ADSC-IV group (n = 18) and ADSC-PPI group (n = 18). ADSCs were labelled with 5-ethynyl-2'-deoxyuridine (EdU), and six rats each in the ADSC-ICI group, ADSC-IV group, and ADSC-PPI group were sacrificed 2, 7, and 28 days after injection. EdU-labelled ADSCs were tracked by immunofluorescence staining. The intracavernosal pressure (ICP)/mean arterial pressure (MAP) ratio, neuronal nitric oxide synthase (nNOS)-positive nerve fibres in the dorsal penile nerve and the smooth muscle/collagen ratio in the cavernosum between groups were also evaluated. ADSCs can significantly improve erectile function through ICI or IV. The two are similar in efficacy and superior to PPI. The mechanism may be that after CN injury, ADSCs are recruited to around the MPG and secrete a variety of neurotrophic factors that promote the repair of the CN, thereby improving erectile function.

Review of the Current Status of Low Intensity Extracorporeal Shockwave Therapy (Li-ESWT) in Erectile Dysfunction (ED), Peyronie's Disease (PD), and Sexual Rehabilitation After Radical Prostatectomy With Special Focus on Technical Aspects of the Different Marketed ESWT Devices Including Personal Experiences in 350 Patients

INTRODUCTION

Although the literature of the positive effects of penile low intensity extracorporeal shockwave therapy is meanwhile substantial, there are substantial differences regarding both the sources of energies and extracorporeal shockwave therapy (ESWT) devices.

OBJECTIVES

To provide an overview on the energy range and energy differences of the 6 currently marketed ESWT devices along with personal ESWT experiences in 350 patients.

METHODS

This review includes all published preclinical and clinical penile ESWT studies with evaluation of the technical differences of the 6 ESWT devices and the personal experiences with these 6 devices in ED and PD. The main outcomes measures were success rates in ED (International Index of Erectile Function-erectile function change, conversion of phosphodiesterase type 5 inhibitors non-responders) and PD (change in deviation and plaque size), differences of used sources of energy, and energy flux densities (EFDs).

RESULTS

3 different sources of energies are used, that is electromagnetic, electrohydraulic, and piezoelectric .The devices markedly distinguish in the available spectrum of the EFD ranging between 0.09 and 0.55 mJ/mm². In terms of the biological effects, the relevant energy parameters are -6 dB and the 5 MPa focus, which differ substantially between the ESWT devices. In addition, a great variability in the treatment protocols and applied energy is obvious. The preliminary own experiences with low intensity extracorporeal shockwave therapy in 160 ED non-responders and 190 patients with PD with success rates of 45% and 47%, respectively, are reported.

CONCLUSION

Positive results were published with all 6 ESWT devices in question in patients with organic ED but with huge differences regarding the EFD and the total energies applied. There is growing evidence that concentrated treatment protocols and increasing energies may yield better results. In this context, it may be argued that at least some of the published studies were markedly underpowered .Owing to the paucity of published studies, the literature of the effects of ESWT in PD and for penile rehabilitation after pelvic surgery is currently not conclusive. Porst H. Review of the Current Status of Low Intensity Extracorporeal Shockwave Therapy (Li-ESWT) in Erectile Dysfunction (ED), Peyronie's Disease (PD), and Sexual Rehabilitation After Radical Prostatectomy With Special Focus on Technical Aspects of the Different Marketed ESWT Devices Including Personal Experiences in 350 Patients. Sex Med 2021;9:93-122.

Small fibre pathology is associated with erectile dysfunction in men with type 2 diabetes

AIMS

The aim of this study was to evaluate the contribution of small and large fibre neuropathy to erectile dysfunction (ED) in men with type 2 diabetes (T2D).

METHODS

Measures of small and large fibre neuropathy were evaluated in 49 participants with T2D and 20 age-matched controls.

RESULTS

ED was present in 59% of participants with T2D. There was no difference in age, duration of diabetes, blood pressure, lipid profile, vibration perception threshold (V) (14.3 ± 7.8 vs 11.2 ± 6.6, P = .429), peroneal (41.4 ± 8.2 vs 44.8 ± 4.4, P = .10) and sural (45.4 ± 5.6 vs 47.1 ± 5.8) nerve conduction velocities (m/s), cold (25.1 ± 3.8 vs 26.2 ± 2.9, P = .815) and warm (43.2 ± 4.0 vs 41.0 ± 3.8) perception thresholds (°C), and deep breathing heart rate variability (18 ± 8 vs 18 ± 8) between participants with and without ED. However, intraepidermal nerve fibre density (no./mm² ) (4.6 ± 2.8 vs 13.7 ± 2.7, P < .001), corneal nerve fibre density (no./mm² ) (23.5 ± 6.8 vs 31.3 ± 8.2, P < .001), corneal nerve fibre branch density (no./mm² ) (55.4 ± 35.3 vs 97.7 ± 46.4, P = .004), corneal nerve fibre length (mm/mm² ) (17.6 ± 6.8 vs 27.3 ± 6.8, P < .001), and sural (7.7 ± 6.1 vs 14.6 ± 6.7, P = .003) and peroneal (2.5 ± 2.0 vs 4.7 ± 2.0, P = .003) nerve amplitudes were significantly lower in participants with ED compared with those without ED.

CONCLUSION

ED affects almost 2/3 of men with T2D and is associated with small nerve fibre damage but preserved nerve conduction and cardiac autonomic function. Corneal confocal microscopy may serve as a useful non-invasive imaging method to identify small fibre damage in patients with T2D and ED.

Co-overexpression of VEGF and GDNF in adipose-derived stem cells optimizes therapeutic effect in neurogenic erectile dysfunction model

Objectives

To evaluate the rapid repair potential of adipose‐derived stem cells (ADSCs) co‐overexpressing VEGF and GDNF on bilateral cavernous nerve injury (BCNI) in rat models. Progressive fibrosis of the penis that occurs shortly after BCNI is a key cause of clinical treatment difficulty of erectile dysfunction (ED). Traditional medications are ineffective for ED caused by BCNI. ADSCs have shown therapeutic effects in animal models, but disappointing in clinical treatment suggests that we should explore optimal treatment of it.

Materials and methods

We extracted ADSCs from rat epididymis. Lentiviral transfection was verified by western blot and immunofluorescence. Thirty‐six SD rats (10 weeks old) were randomly divided into six groups (n = 6 per group): sham surgery, and remaining five BCNI groups transplanted PBS or ADSCs which were genetically modified by vehicle, VEGF (ADSC‐V), GDNF (ADSC‐G), or VEGF&GDNF (ADSC‐G&V) around major pelvic ganglion (MPG). We investigated the therapeutic effects of BCNI rat model which is characterized by ED, penile tissue fibrosis and hypoxia, and lack of nitrogen nerves or vascular atrophy.

Results

Erectile function was almost recovered after 2 weeks of transplantation of ADSC‐G&V, promoted cavernous nerve repair, prevented penile fibrosis and preserving the vascular endothelium, which was significant differences amongst ADSC‐V or ADSC‐G. Moreover, GM‐ADSCs were detected in MPG and penis, indicating that their participation in repair of target organs and transverse nerves.

Conclusions

These promising data indicate that ADSCs co‐overexpressed VEGF and GDNF‐induced synergistic effects, make it a potential tool for recovering of erectile function speedily after BCNI.

Male sexual dysfunction in obesity: The role of sex hormones and small fibre neuropathy

Context

Multiple factors contribute to sexual dysfunction in men with obesity. Sex hormone levels are commonly abnormal in men with obesity and this abnormality is often the focus of management in clinical practice. The role of small fibre neuropathy in obesity-related sexual dysfunction is not well established.

Objective

We aimed to investigate the relationship between sexual function, sex hormone levels and small nerve fibre morphology in men with severe obesity.

Materials and methods

A prospective study of 29 men with severe obesity was undertaken. Sexual function was assessed using the European Male Ageing Study Sexual Function Questionnaire. Small nerve fibre morphology was quantified using corneal confocal microscopy. Sex hormone levels were measured by mass spectrophotometry.

Results

Erectile dysfunction was present in 72% of the cohort with a higher prevalence of diabetes among the symptomatic group (88% vs 38%, p = 0.006). Corneal nerve fibre length (CNFL) and corneal nerve fibre density (CNFD) were both significantly lower in participants with erectile dysfunction compared to those without (p = 0.039 and p = 0.048 respectively). The erectile function score correlated with CNFL (r = -0.418, p = 0.034) and CNFD (r = -0.411, p = 0.037). Total testosterone and calculated free testosterone levels did not differ significantly between men with or without erectile dysfunction (median 8.8 nmol/L vs 9.0 nmol/L, p = 0.914; and median 176 pmol/L vs 179 pmol/L, p = 0.351 respectively), infrequent sexual thoughts (median 8.1 nmol/L vs 9.2 nmol/L, p = 0.650; and median 184 pmol/L, vs 176 pmol/L, p = 0.619 respectively) and decreased morning erections (median 9.0 nmol/L vs 8.8 nmol/L, p = 0.655; and median 170 pmol/L vs 193 pmol/L, p = 0.278 respectively).

Conclusion

Sexual dysfunction is highly prevalent in men with severe obesity. We found an association between small fibre neuropathy with erectile dysfunction with presence of diabetes a likely a significant contributing factor. We found no associations between testosterone levels with sexual symptoms (including frequency of sexual thoughts). The influence of small nerve fibre neuropathy on response to therapeutic interventions and whether interventions that improve small fibre neuropathy can improve erectile function in this population merits further study.

Erectile Dysfunction: A Primer for in Office Management

Introduction: Optimizing erectile dysfunction (ED) remains a clinically significant endeavor as insufficient outcomes from oral, injectable and even surgical approaches to treatment remain less than ideal. In this report, we integrate evolving knowledge and provide an algorithmic approach for the clinician to fine-tune management. Methods: We performed a PubMed and Medline search of Erectile Dysfunction treatment optimization, enhanced patient efficacy for ED, and why men fail ED treatment. All relevant papers for the past two decades were reviewed. Results: Establishing the goals and objectives of the patient and partner while providing detailed instructions for treatment can minimize failures and create an environment that allows treatment optimization. A thorough work-up may identify reversible or contributing causes. We identified several areas where treatment of ED could be optimized. These include; management of associated medical conditions, lifestyle improvements, PDE5 inhibitor prescription strategies, management of hypogonadism and the initiation of intracavernosal injection therapy (ICI). Conclusions: In our view, once a man presents for help to the clinician, use of the simple strategies identified in this review to optimize the tolerability, safety and effectiveness of the selected treatment should result in enhanced patient and partner satisfaction, with improved outcomes.

Transplantation of induced pluripotent stem cell-derived mesenchymal stem cells improved erectile dysfunction induced by cavernous nerve injury

Erectile dysfunction (ED) is an important kind of postoperative complication of pelvic surgery that affects patients' quality of life. Transplantation of mesenchymal stem cells (MSC) has been found to alleviate ED caused by cavernous nerve injury (CNI) in rats. However, little is known about whether induced pluripotent stem cell-derived mesenchymal stem cells (iMSC) have a therapeutic effect on CNI ED. We established an ED model on rats and evaluated the effect of iMSC on it. Methods: Eight-week-old male Sprague-Dawley rats were assigned to four groups and received following operation: sham operation (sham group); bilateral CNI and phosphate-buffered saline (PBS) injections (PBS group); bilateral CNI and adipose-derived mesenchymal stem cells transplantation (adMSC group); or bilateral CNI and iMSC injection (iMSC group). After therapy, the cavernous nerve was stimulated by electricity and the intracavernous pressure (IAP)/mean arterial blood pressure (MAP) was measured. The endothelial and smooth muscle tissue in the penis was assessed histologically with Masson's trichrome stain. Immunofluorescence/immunohistochemical stains were applied for the detection of nNOS, vWF, eNOS, SMA, Desmin, S100β, and caspase-3. Nude rats CNI ED model was established for the evaluation of iMSC longevity and differentiation capacity. The paracrine factors were assessed by real-time PCR. Results: Transplantation of iMSC significantly restored the IAP/MAP in this CNI ED model and showed long-term effects. It could rescue the expression of vWF, eNOS, SMA, and Desmin, which indicated the alleviation of endothelial and smooth muscle tissues of the penis. iMSC therapy also could increase the expression of nNOS in the cavernosum and S100β in the major pelvic ganglia (MPG) which contributed to the erectile function. Moreover, the level of BAX and caspase-3 were reduced and Bcl-2 was increased, which indicated the anti-apoptosis effects of iMSC. The iMSC showed little transdifferentiation and exerted their function by activating the secretome of the host. Conclusion: Transplantation of iMSC significantly improved ED induced by CNI. The iMSC may exert their effects via paracrine factors and may be a promising therapeutic candidate for treating CNI ED in the future.

Sildenafil in postprostatectomy erectile dysfunction (perspective)

Erectile dysfunction (ED) is a common side effect to radical prostatectomies, even with nerve-sparing procedures. To ameliorate the problem so-called "penile rehabilitation" programs have been developed. The most widely used method of this is subscribing sildenafil or other PDE5-inhibitors to patients following surgery. This is based on a theory that these drugs may increase penile oxygenation and provide antiapoptotic factors (primarily NO and cGMP), thus protecting the penile tissue in a period with reduced nerve function following the surgery. Preclinical studies have confirmed the potential of sildenafil in this context and early human trials have suggested that a steady ingestion of sildenafil might protect the structural integrity of the penis. However, subsequent well-designed trials have not been able to confirm the initial findings. This fits well with sildenafil's mechanism of action because it does not actually induce erections or the production of either nitric oxide or cGMP. Rather, the drug enhances effects of an erectile response induced by neurotransmitters from the cavernous nerves. Therefore, sildenafil should no longer be offered as a sole means of penile rehabilitation. Rather, more research is needed, and clinicians need to apply a broader concept of sexual rehabilitation in postprostatectomy ED.

Penile rehabilitation for postprostatectomy erectile dysfunction

BACKGROUND

Despite efforts to preserve the neurovascular bundles with nerve-sparing surgery, erectile dysfunction remains common following radical prostatectomy. Postoperative penile rehabilitation seeks to restore erectile function but results have been conflicting.

OBJECTIVES

To evaluate the effects of penile rehabilitation strategies in restoring erectile function following radical prostatectomy for prostate cancer.

SEARCH METHODS

We performed a comprehensive search of multiple databases (CENTRAL, MEDLINE, Embase), the Cochrane Library, Web of Science, clinical trial registries (ClinicalTrials.gov, International Clinical Trials Registry Platform) and a grey literature repository (Grey Literature Report) from their inception through to 3 January 2018. We also searched the reference lists of other relevant publications and abstract proceedings. We applied no language restrictions.

SELECTION CRITERIA

We included randomised or quasi-randomised trials with a parallel or cross-over design.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. Two review authors independently screened the literature, extracted data, assessed risk of bias and rated quality of evidence according to GRADE on a per-outcome basis. Primary outcomes were self-reported potency, erectile function measured by validated questionnaires (with potency defined as an International Index of Erectile Function (IIEF-EF) score of 19 or greater and or an IIEF-5 of score of 17 or greater) and serious adverse events. For all quality of life assessments on a continuous scale, higher values indicated better quality of life.

MAIN RESULTS

We included eight randomised controlled trials with 1699 participants across three comparisons. This abstract focuses on the primary outcomes of this review only.Scheduled phosphodiesterase type 5 inhibitors (PDE5I) versus placebo or no treatmentScheduled PDE5I may have little or no effect on short-term (up to 12 months) self-reported potency (risk ratio (RR) 1.13, 95% confidence interval (CI) 0.91 to1.41; very low quality evidence), which corresponds to 47 more men with self-reported potency per 1000 (95% CI 33 fewer to 149 more) and short-term erectile function as assessed by a validated instrument (RR 1.11, 95% CI 0.80 to 1.55; very low quality evidence), which corresponds to 28 more men per 1000 (95% CI 50 fewer to 138 more), but we are very uncertain of both of these findings. Scheduled PDE5I may result in fewer serious adverse events compared to placebo (RR 0.32, 95% CI 0.11 to 0.94; low quality evidence), though this does not appear biologically plausible and may represent a chance finding. We are also very uncertain of this finding. We found no long-term (longer than 12 months) data for any of the three primary outcomes.Scheduled PDE5I versus on-demand PDE5I Daily PDE5I appears to result in little to no difference in both short-term and long-term (greater than 12 months) self-reported potency (short term: RR 0.97, 95% CI 0.62 to 1.53; long term: RR 1.00, 95% CI 0.60 to 1.67; both very low quality evidence); this corresponds to nine fewer men with self-reported short-term potency per 1000 (95% CI 119 fewer to 166 more) and zero fewer men with self-reported long-term potency per 1000 (95% CI 153 fewer to 257 more). We are very uncertain of these findings. Daily PDE5I appears to result in little to no difference in short-term and long-term erectile function (short term: RR 1.00, 95% CI 0.65 to 1.55; long term; RR 0.74, 95% CI 0.48 to 1.14; both very-low quality evidence), which corresponds to zero men with short-term erectile dysfunction per 1000 (95% CI 80 fewer to 125 more) and 119 fewer men with long-term erectile dysfunction per 1000 (95% CI 239 fewer to 64 more). We are very uncertain of these findings. Scheduled PDE5I may result in little or no effects on short-term adverse events (RR 0.69 95% CI 0.12 to 4.04; very low quality evidence), which corresponds to seven fewer men with short-term serious adverse events (95% CI 18 fewer to 64 more), but we are very uncertain of these findings. We found no long-term data for serious adverse events.Scheduled PDE5I versus scheduled intraurethral prostaglandin E1At short-term follow-up, daily PDE5I may result in little or no effect on self-reported potency (RR 1.10, 95% CI 0.79, to 1.52; very low quality evidence), which corresponds to 46 more men per 1000 (95% CI 97 fewer to 241 more). Daily PDE5I may result in a small improvement of erectile function (RR 1.64, 95% CI 0.84 to 3.20; very low quality evidence), which corresponds to 92 more men per 1000 (95% CI 23 fewer to 318 more) but we are very uncertain of both these findings. We found no long-term (longer than 12 months) data for any of the three primary outcomes.We found no evidence for any other comparisons and were unable to perform any of the preplanned subgroup analyses based on nerve-sparing approach, age or baseline erectile function.

AUTHORS' CONCLUSIONS

Based on mostly very-low and some low-quality evidence, penile rehabilitation strategies consisting of scheduled PDE5I use following radical prostatectomy may not promote self-reported potency and erectile function any more than on demand use.

Advances in stem cell therapy for erectile dysfunction

INTRODUCTION

Stem cell (SC) application is a promising area of research in regenerative medicine, with the potential to treat, prevent, and cure disease. In recent years, the number of studies focusing on SCs for the treatment of erectile dysfunction (ED) and other sexual dysfunctions has increased significantly.

AREAS COVERED

This review includes critical ED targets and preclinical studies, including the use of SCs and animal models in diabetes, aging, cavernous nerve injury, and Peyronie's disease. A literature search was performed on PubMed for English articles.

EXPERT OPINION

Combination treatment offers better results than monotherapy to improve pathological changes in diabetic ED. Regenerative medicine is a promising approach for the maintenance of sexual health and erectile function later in life. Cavernous nerve regeneration and vascular recovery employing SC treatment may be focused on radical prostatectomy-induced ED. Notwithstanding, there are a number of hurdles to overcome before SC-based therapies for ED are considered in clinical settings. Paracrine action, not cellular differentiation, appears to be the principal mechanism of action underlying SC treatment of ED. Intracavernosal injection of a single SC type should be the choice protocol for future clinical trials.

Efficacy and safety of low-intensity shock wave therapy in penile rehabilitation post nerve-sparing radical cystoprostatectomy: a randomized controlled trial

AIM

To evaluate the role of low-intensity extra corporeal shock wave therapy (LI-ESWT) in penile rehabilitation (PR) post nerve-sparing radical cystoprostatectomy (NS-RCP).

MATERIALS AND METHODS

This study included 152 sexually active men with muscle invasive bladder cancer. After bilateral NS-RCP with orthotopic diversion by a single expert surgeon between June 2014 and July 2016, 128 patients were available categorized into three groups: LI-ESWT group (42 patients), phosphodiesterase type-5 inhibitors (PDE5i) group (43 patients), and control group (43 patients).

RESULTS

Mean age was 53.2 ± 6.5 years. Mean ± SD follow-up period was 21 ± 8 months. During first follow-up FU1, all patients of the three groups had insufficient erection for vaginal penetration; with decrease of preoperative IIEF-EF mean score from 27.9 to 6.9. Potency recovery rates at 9 months were 76.2%, 79.1%, and 60.5% in LI-ESWT, PDE5i, and control groups, respectively. There was statistically significant increase in IIEF-EF and EHS scores during all follow-up periods in all the study groups (p < 0.001). However, there was no significant difference between the three groups during all follow-up periods. Statistical evaluation showed no significant difference in continence and oncological outcomes during all follow-up points among the three groups (p = 0.55 and 0.07, respectively).

CONCLUSIONS

During last follow-up, 16% more patients in LI-ESWT group had recovery of potency as compared to the control group. Although the difference is not statistically significant, but of clinical importance. LI-ESWT is safe as oral PDE5i in penile rehabilitation post nerve-sparing radical cystoprostatectomy.

Are We Improving Erectile Function Recovery After Radical Prostatectomy? Analysis of Patients Treated over the Last Decade

BACKGROUND

The last decade has seen several advances in radical prostatectomy (RP) technique and post-RP care that are relevant to erectile function (EF) recovery.

OBJECTIVE

We examined whether these practice changes have led to observed improvements in EF rates over time.

DESIGN, SETTING, AND PARTICIPANTS

We identified 2364 patients treated with either open or minimally-invasive RP at a single academic center in 2008-2015. To mitigate confounding by the surgical learning curve, only patients treated by surgeons who performed at least 100 procedures were considered.

INTERVENTION

EF before and after RP was assessed by the International Index of Erectile Function 6 (IIEF-6), with recovery defined as IIEF-6 ≥24.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We analyzed EF recovery rates of patients treated with bilateral nerve-sparing surgery and free from adjuvant/salvage treatment at the time of EF assessment. Local polynomial regression analyses explored changes in the outcomes over time. Linear and logistic regression analyses were used to estimate the influence of year of surgery on baseline variables and EF recovery.

RESULTS AND LIMITATIONS

We observed a significant decrease over time of the EF recovery rates at both 12 and 24mo post-RP (all p=0.01). However, patient's age at surgery increased over time (mean increase of 0.5 per year; p<0.01), with a resultant increase in risk of comorbidity (odds ratio [OR]=1.1, 95% confidence interval [CI]: 1.02-1.15; p=0.008) and thus decrease in baseline IIEF-6 score (0.35 points per year; p=0.0003). After accounting for baseline and pathological characteristics, urinary function, and type of surgery in a multivariable analysis, year of surgery was not associated with EF recovery (12mo: OR=0.97, 95% CI: 0.91-1.03, p=0.4; 24mo: OR=0.97, 95% CI: 0.91-1.03, p=0.3).

CONCLUSIONS

Findings from a high-volume center suggest that, despite the advancements in surgical and postoperative care, EF outcomes after RP have not improved over the last decade. Additional strategies are required to improve EF recovery after RP.

PATIENT SUMMARY

The probability of regaining potency after surgery for prostate cancer did not improve over the last decade; more efforts are needed to improve patient's care after radical prostatectomy.

Transplantation of Human Urine-Derived Stem Cells Transfected with Pigment Epithelium-Derived Factor to Protect Erectile Function in a Rat Model of Cavernous Nerve Injury

The aim of this study was to investigate whether intracavernous injection of urine-derived stem cells (USCs) or USCs genetically modified with pigment epithelium-derived factor (PEDF) could protect the erectile function and cavernous structure in a bilateral cavernous nerve injury-induced erectile dysfunction (CNIED) rat model. USCs were cultured from the urine of six healthy male donors. Seventy-five rats were randomly divided into five groups ( n = 15 per group): sham, bilateral cavernous nerve (CN) crush injury (BCNI), USC, USC^GFP+, and USC^GFP/PEDF+ groups. The sham group received only laparotomy without CN crush injury and intracavernous injection with phosphate-buffered saline (PBS). All of the other groups were subjected to BCNI and intracavernous injection with PBS, USCs, USCs^GFP+, or USCs^GFP/PEDF+, respectively. The total intracavernous pressure (ICP) and the ratio of ICP to mean arterial pressure (ICP/MAP) were recorded. The penile dorsal nerves, the endothelium, and the smooth muscle were assessed within the penile tissue. The USC and USC^GFP/PEDF+ groups displayed more significantly enhanced ICP and ICP/MAP ratio ( p < 0.05) 28 days after cell transplantation. Immunohistochemistry (IHC) and Western blot analysis demonstrated that the protection of erectile function and the cavernous structure by USCs^GFP/PEDF+ was associated with an increased number of nNOS-positive fibers within the penile dorsal nerves, improved expression of endothelial markers (CD31 and eNOS) and a smooth muscle marker (smoothelin), an enhanced smooth muscle to collagen ratio, decreased expression of transforming growth factor-β1 (TGF-β1), and decreased cell apoptosis in the cavernous tissue. The paracrine effect of USCs and USCs^GFP/PEDF+ prevented the destruction of erectile function and the cavernous structure in the CNIED rat model by nerve protection, thereby improving endothelial cell function, increasing the smooth muscle content, and decreasing fibrosis and cell apoptosis in the cavernous tissue.

Surgical Factors Associated With Male and Female Sexual Dysfunction After Radical Cystectomy: What Do We Know and How Can We Improve Outcomes?

BACKGROUND

Sexual dysfunction after radical cystectomy (RC) is a frequent, though commonly overlooked symptom for both men and women. Improved oncological outcomes and the rising number of bladder cancer survivors mandate physicians to closely address and evaluate post-surgical sexual dysfunction and offer goal-directed treatment. Improvements in RC surgical techniques that promote post-operative sexual function have been proposed, alongside new quality-of-life inventories and sexual function therapeutic options; however, rigorous studies in the field are lacking.

AIM

To provide a comprehensive overview of post-RC sexual dysfunction and discuss new surgical techniques, sexual dysfunction evaluation, and novel treatment strategies.

METHODS

A non-systematic narrative review of the literature was performed through PubMed about sexual dysfunction in men and women after RC.

OUTCOMES

We reported on the surgical anatomy of sexual function-sparing RC, the most common inventories used to investigate sexual function in post-RC patients, and current treatment options.

RESULTS

Extensive knowledge about pelvic anatomy and nerve-sparing surgical techniques in men is well understood from studies about prostate anatomy and nerve-sparing prostatectomy. However, anatomical and surgical details of sexual-sparing RC in women needs further characterization. Several questionnaires are used to investigate sexuality after RC, but a standardized approach is still missing. Therapeutic options are available to treat sexual dysfunction, but limited studies have been conducted to specifically address the post-RC population.

CONCLUSION

Further work is needed to understand the best strategies to prevent and treat sexual dysfunction in patients after RC. Pederzoli F, Campbell JD, Matsui H, et al. Surgical Factors Associated With Male and Female Sexual Dysfunction After Radical Cystectomy: What Do We Know and How Can We Improve Outcomes? Sex Med Rev 2018;6:469-481.

Long-term penile morphometric alterations in patients treated with robot-assisted versus open radical prostatectomy

Neglected side effects after radical prostatectomy have been previously reported. In this context, the prevalence of penile morphometric alterations has never been assessed in robot-assisted radical prostatectomy series. We aimed to assess prevalence of and predictors of penile morphometric alterations (i.e. penile shortening or penile morphometric deformation) at long-term follow-up in patients submitted to either robot-assisted (robot-assisted radical prostatectomy) or open radical prostatectomy. Sexually active patients after either robot-assisted radical prostatectomy or open radical prostatectomy prospectively completed a 28-item questionnaire, with sensitive issues regarding sexual function, namely orgasmic functioning, climacturia and changes in morphometric characteristics of the penis. Only patients with a post-operative follow-up ≥ 24 months were included. Patients submitted to either adjuvant or salvage therapies or those who refused to comprehensively complete the questionnaire were excluded from the analyses. A propensity-score matching analysis was implemented to control for baseline differences between groups. Logistic regression models tested potential predictors of penile morphometric alterations at long-term post-operative follow-up. Overall, 67 (50%) and 67 (50%) patients were included after open radical prostatectomy or robot-assisted radical prostatectomy, respectively. Self-rated post-operative penile shortening and penile morphometric deformation were reported by 75 (56%) and 29 (22.8%) patients, respectively. Rates of penile shortening and penile morphometric deformation were not different after open radical prostatectomy and robot-assisted radical prostatectomy [all p > 0.5]. At univariable analysis, self-reported penile morphometric alterations (either penile shortening or penile morphometric deformation) were significantly associated with baseline international index of erectile function-erectile function scores, body mass index, post-operative erectile function recovery, year of surgery and type of surgery (all p < 0.05). At multivariable analysis, robot-assisted radical prostatectomy was independently associated with a lower risk of post-operative penile morphometric alterations (OR: 0.38; 95% CI: 0.16-0.93). Self-perceived penile morphometric alterations were reported in one of two patients after radical prostatectomy at long-term follow-up, with open surgery associated with a potential higher risk of this self-perception.

Small-fibre neuropathy in men with type 1 diabetes and erectile dysfunction: a cross-sectional study

AIMS/HYPOTHESIS

The aim of this study was to identify the contribution of small- and large-fibre neuropathy to erectile dysfunction in men with type 1 diabetes mellitus.

METHODS

A total of 70 participants (29 without and 41 with erectile dysfunction) with type 1 diabetes and 34 age-matched control participants underwent a comprehensive assessment of large- and small-fibre neuropathy.

RESULTS

The prevalence of erectile dysfunction in participants with type 1 diabetes was 58.6%. After adjusting for age, participants with type 1 diabetes and erectile dysfunction had a significantly higher score on the Neuropathy Symptom Profile (mean ± SEM 5.3 ± 0.9 vs 1.8 ± 1.2, p = 0.03), a higher vibration perception threshold (18.3 ± 1.9 vs 10.7 ± 2.4 V, p = 0.02), and a lower sural nerve amplitude (5.0 ± 1.1 vs 11.7 ± 1.5 mV, p = 0.002), peroneal nerve amplitude (2.1 ± 0.4 vs 4.7 ± 0.5 mV, p < 0.001) and peroneal nerve conduction velocity (34.8 ± 1.5 vs 41.9 ± 2.0 m/s, p = 0.01) compared with those without erectile dysfunction. There was also evidence of a marked small-fibre neuropathy with an impaired cold threshold (19.7 ± 1.4°C vs 27.3 ± 1.8°C, p = 0.003), warm threshold (42.9 ± 0.8°C vs 39.0 ± 0.9°C, p = 0.005) and heart rate variability (21.5 ± 3.1 vs 30.0 ± 3.7 beats/min, p = 0.001) and reduced intraepidermal nerve fibre density (2.8 ± 0.7 vs 5.9 ± 0.7/mm, p = 0.008), corneal nerve fibre density (12.6 ± 1.5 vs 23.9 ± 2.0/mm2, p < 0.001), corneal nerve branch density (12.7 ± 2.5 vs 31.6 ± 3.3/mm2, p < 0.001) and corneal nerve fibre length (8.3 ± 0.7 vs 14.5 ± 1.0 mm/mm2, p < 0.001) in participants with type 1 diabetes and erectile dysfunction. Erectile dysfunction correlated significantly with measures of both large- and small-fibre neuropathy.

CONCLUSIONS/INTERPRETATION

Small-fibre neuropathy is prominent in patients with type 1 diabetes, and is associated with erectile dysfunction and can be objectively quantified using corneal confocal microscopy. This may allow the identification of patients who are less likely to respond to conventional therapies such as phosphodiesterase type 5 inhibitors.

Off-Target Effect of Sildenafil on Postsurgical Erectile Dysfunction: Alternate Pathways and Localized Delivery System

INTRODUCTION

There is no consensus on the best oral phosphodiesterase type 5 inhibitor (PDE5I) for patients undergoing penile rehabilitation after surgical nerve injury.

AIM

To determine the mechanism of PDE5I on cultured neuronal cells and the effectiveness of local drug delivery using nanospheres (NSPs) to sites of nerve injury in a rat model of bilateral cavernous nerve injury (BCNI).

METHODS

The effects of sildenafil, tadalafil, and vardenafil on cyclic adenosine monophosphate, cyclic guanosine monophosphate, and cell survival after exposure to hypoxia and H₂O₂ were measured in PC12, SH-SY5Y, and NTERA-2 (NT2) cell cultures. The effects of phosphodiesterase type 4 inhibitor (PDE4I) and PDE5I on neuronal cell survival were evaluated. Male rats underwent BCNI and were untreated (BCNI), immediately treated with application of empty NSPs (BCNI + NSP), NSPs containing sildenafil (Sild + NSP), or NSPs containing rolipram (Rol + NSP).

MAIN OUTCOME MEASURES

Viability of neuronal cells was measured. Intracavernous pressure changes after cavernous nerve electrostimulation and expression of neurofilament, nitric oxide synthase, and actin in mid-shaft of penis were analyzed 14 days after injury.

RESULTS

Sildenafil and rolipram significantly decreased cell death after exposure to H₂O₂ and hypoxia in PC12, SH-SY5Y, and NT2 cells. PC12 cells did not express PDE5 and knockdown of PDE4 significantly increased cell viability in PC12, SH-SY5Y, and NT2 cells exposed to hypoxia. The ratio of intracavernous pressure to mean arterial pressure and expression of penile neurofilament, nitric oxide synthase, and actin were significantly higher in the Sild + NSP and Rol + NSP groups than in the BCNI and BCNI + NSP groups. Limitations included analysis in only two PDE families using only a single dose.

CONCLUSION

Sildenafil showed the most profound neuroprotective effect compared with tadalafil and vardenafil. Sildenafil- or rolipram-loaded NSP delivery to the site of nerve injury prevented erectile dysfunction and led to increased neurofilament, nitric oxide synthase, smooth muscle content in rat penile tissue after BCNI.

Pharmacodynamics, pharmacokinetics and clinical efficacy of phosphodiesterase-5 inhibitors

INTRODUCTION

Phosphodiesterase type 5 inhibitors (PDE5Is) are the first-line drugs in the management of erectile dysfunction (ED). However, over the past two decades tremendous efforts have been made to identify new clinical uses of PDE5Is beyond their roles in ED. Areas covered: Basic science articles, clinical trials, reviews, and meta-analysis published between 1996 and 2015 were searched using MEDLINE (PubMed interface) to collect the most relevant and impactful studies from our perspectives as practicing urologists. This review mainly focuses on the level one evidence-based clinical efficacy and drug-related toxicity of oral PDE5Is. In addition, drug discovery, pharmacokinetics and pharmacodynamics, potential use in other diseases, and future directions are discussed. Expert opinion: On-demand PED5Is for the treatment of ED has shifted toward chronic administration in a broad spectrum of conditions that are thought to be associated with endovascular health. Several studies have shown that PDE5Is may play a cardioprotective or neuroprotective role. Further studies are under way to verify beneficial effects of PDE5I in non-urological conditions.

Phosphodiesterase-5 Inhibitors and Vacuum Erection Device for Penile Rehabilitation After Laparoscopic Nerve-Preserving Radical Proctectomy for Rectal Cancer: A Prospective Controlled Trial

The current study sought to clarify the role of phosphodiesterase type 5 inhibitors (PDE-5i) and a vacuum erection device (VED) in penile rehabilitation after laparoscopic nerve-preserving radical proctectomy (LNRP) for rectal cancer. Participants were assigned to one of the following arms-no-intervention, nightly use of sildenafil 25 mg for 3 months after surgery, or concurrent use of nightly sildenafil 25 mg/day for 3 months and a vacuum erection device (VED) 10 to 15 minutes/day for 3 months-in a nonrandomized fashion. All participants had a follow-up of over 12 months prospectively, and patients had baseline, 3-, 6-, and 12-month assessment based on the International Index of Erectile Function-5 (IIEF-5). Seventy-one cases were included in final analyses. In the no-intervention group, the mean baseline IIEF-5 score of 21.9 decreased rapidly to 5.0 at 3 months ( p < .001), 9.2 at 6 months ( p < .001), and stayed at 10.9 at 12 months ( p < .001). In the single therapy group, the mean baseline IIEF-5 score of 22.4 decreased dramatically to 9.0 at 3 months ( p < .001), 14.9 at 6 months ( p = .005), and stayed at 15.1 at 12 months ( p = .005). In the combined therapy group, the mean baseline IIEF-5 score of 23.0 decreased slightly to 15.0 at 3 months ( p = .005), 18.0 at 6 months ( p = .038), and maintained at 18.7 at 12 months ( p = .163). Findings suggested an over 50% decline in the quality of erection function of the patients after LNRP. The early use of PDE-5i alone or combined use of PDE-5i and VED after LNRP maintained erectile function at 12 months.

Postprostatectomy Erectile Dysfunction: A Review

In the current era of the early diagnosis of prostate cancer (PCa) and the development of minimally invasive surgical techniques, erectile dysfunction (ED) represents an important issue, with up to 68% of patients who undergo radical prostatectomy (RP) complaining of postoperative erectile function (EF) impairment. In this context, it is crucial to comprehensively consider all factors possibly associated with the prevention of post-RP ED throughout the entire clinical management of PCa patients. A careful assessment of both oncological and functional baseline characteristics should be carried out for each patient preoperatively. Baseline EF, together with age and the overall burden of comorbidities, has been strongly associated with the chance of post-RP EF recovery. With this goal in mind, internationally validated psychometric instruments are preferable for ensuring proper baseline EF evaluations, and questionnaires should be administered at the proper time before surgery. Careful preoperative counselling is also required, both to respect the patient's wishes and to avoid false expectations regarding eventual recovery of baseline EF. The advent of robotic surgery has led to improvements in the knowledge of prostate surgical anatomy, as reflected by the formal redefinition of nerve-sparing techniques. Overall, comparative studies have shown significantly better EF outcomes for robotic RP than for open techniques, although data from prospective trials have not always been consistent. Preclinical data and several prospective randomized trials have demonstrated the value of treating patients with oral phosphodiesterase 5 inhibitors (PDE5is) after surgery, with the concomitant potential benefit of early re-oxygenation of the erectile tissue, which appears to be crucial for avoiding the eventual penile structural changes that are associated with postoperative neuropraxia and ultimately result in severe ED. For patients who do not properly respond to PDE5is, proper counselling regarding intracavernous treatment should be considered, along with the further possibility of surgical treatment for ED involving the implantation of a penile prosthesis.

Exploratory Decision-Tree Modeling of Data from the Randomized REACTT Trial of Tadalafil Versus Placebo to Predict Recovery of Erectile Function After Bilateral Nerve-Sparing Radical Prostatectomy

BACKGROUND

Understanding predictors for the recovery of erectile function (EF) after nerve-sparing radical prostatectomy (nsRP) might help clinicians and patients in preoperative counseling and expectation management of EF rehabilitation strategies.

OBJECTIVE

To describe the effect of potential predictors on EF recovery after nsRP by post hoc decision-tree modeling of data from A Study of Tadalafil After Radical Prostatectomy (REACTT).

DESIGN, SETTING, AND PARTICIPANTS

Randomized double-blind double-dummy placebo-controlled trial in 423 men aged <68 yr with adenocarcinoma of the prostate (Gleason ≤7, normal preoperative EF) who underwent nsRP at 50 centers from nine European countries and Canada.

INTERVENTION

Postsurgery 1:1:1 randomization to 9-mo double-blind treatment with tadalafil 5mg once a day (OaD), tadalafil 20mg on demand, or placebo, followed by a 6-wk drug-free-washout, and a 3-mo open-label tadalafil OaD treatment.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Three decision-tree models, using the International Index of Erectile Function-Erectile Function (IIEF-EF) domain score at the end of double-blind treatment, washout, and open-label treatment as response variable. Each model evaluated the association between potential predictors: presurgery IIEF domain and IIEF single-item scores, surgical approach, nerve-sparing score (NSS), and postsurgery randomized treatment group.

RESULTS AND LIMITATIONS

The first decision-tree model (n=422, intention-to-treat population) identified high presurgery sexual desire (IIEF item 12: ≥3.5 and <3.5) as the key predictor for IIEF-EF at the end of double-blind treatment (mean IIEF-EF: 14.9 and 11.1), followed by high confidence to get and maintain an erection (IIEF item 15: ≥3.5 and <3.5; IIEF-EF: 15.4 and 7.1). For patients meeting these criteria, additional non-IIEF-related predictors included robot-assisted laparoscopic surgery (yes or no; IIEF-EF: 19.3 and 12.6), quality of nerve sparing (NSS: <2.5 and ≥2.5; IIEF-EF: 14.3 and 10.5), and treatment with tadalafil OaD (yes and no; IIEF-EF: 17.6 and 14.3). Additional analyses after washout and open-label treatment identified high presurgery intercourse satisfaction as the key predictor.

CONCLUSIONS

Exploratory decision-tree analyses identified high presurgery sexual desire, confidence, and intercourse satisfaction as key predictors for EF recovery. Patients meeting these criteria might benefit the most from conserving surgery and early postsurgery EF rehabilitation. Strategies for improving EF after surgery should be discussed preoperatively with all patients; this information may support expectation management for functional recovery on an individual patient level.

PATIENT SUMMARY

Understanding how patient characteristics and different treatment options affect the recovery of erectile function (EF) after radical surgery for prostate cancer might help physicians select the optimal treatment for their patients. This analysis of data from a clinical trial suggested that high presurgery sexual desire, sexual confidence, and intercourse satisfaction are key factors predicting EF recovery. Patients meeting these criteria might benefit the most from conserving surgery (robot-assisted surgery, perfect nerve sparing) and postsurgery medical rehabilitation of EF.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01026818.

Prevention and management of post prostatectomy erectile dysfunction

Sexual dysfunction is common in patients with prostate cancer (PC) following radical prostatectomy (RP). Review the available literature concerning prevention and management strategies for post-RP erectile function (EF) impairment in terms of preoperative patient characteristics, intra and postoperative factors that may influence EF recovery, and postoperative treatments for erectile dysfunction (ED). A literature search was performed using Google and PubMed database for English-language original and review articles, either published or e-published up to July 2013. The literature still demonstrates a great inconsistency in the definition of what is considered normal EF both before and after RP. Thus, using validated psychometric instruments with recognized cut-offs for normalcy and severity during the pre- and post-operative evaluation should be routinely considered. Therefore, a comprehensive discussion with the patient about the true prevalence of postoperative ED, the concept of spontaneous or pharmacologically-assisted erections, and the difference between “back to baseline” EF and “erections adequate enough to have successful intercourse” clearly emerge as key issues in the eventual understanding of post-RP ED prevention and promotion of satisfactory EF recovery. Patient factors (including age, baseline EF, comorbid conditions status), cancer selection (non- vs. uni- vs. bilateral nerve-sparing), type of surgery (i.e., intra vs. inter vs. extrafascial surgeries), surgical techniques (i.e., open, laparoscopic and robotically-assisted RP), and surgeon factors (i.e., surgical volume and surgical skill) represent the key significant contributors to EF recovery. A number of preclinical and clinical data show that rehabilitation and treatment in due time are undoubtedly better than leaving the erectile tissue to its unassisted postoperative fate. The role of postoperative ED treatment for those patients who received a non-nerve-sparing RP was also extensively discussed. Optimal outcomes are achieved mainly by the careful choice of the correct patient for the correct type of surgery. Despite a plethora of potential rehabilitative approaches, they should be only considered as “strategies”, since incontrovertible evidence of their effectiveness for improving natural EF recovery is limited. Conversely, numerous effective therapeutic options are available for treating post-RP ED.

Pharmacologic and surgical therapies for sexual dysfunction in male cancer survivors

The recent recognition that many men experience sexual dysfunction following their diagnosis and treatment of genitourinary cancers, has led to the development multiple varied strategies that attempt to restore or preserve that function. In this manuscript we review the understanding of why it happens, highlight novel management strategies and discuss the concept of penile rehabilitation (PR) following prostate cancer (PCa) treatment, glans preserving strategies among men diagnosed with penile cancer and address the controversial issue of testosterone therapy in men with PCa.

Radiation Dose to the Penile Structures and Patient-Reported Sexual Dysfunction in Long-Term Prostate Cancer Survivors

AIM

The involvement of various penile structures in radiotherapy (RT)-induced sexual dysfunction among prostate cancer survivors remains unclear and domains beyond erectile dysfunction such as orgasm, and pain have typically not been considered. The purpose of this study was to investigate sexual dysfunction post-RT for localized prostate cancer and to examine whether radiation dose to different penile structures can explain these symptoms.

METHODS

We investigated sexual dysfunction in two treated prostate cancer cohorts and in one non-pelvic-irradiated cohort, 328 sexually active men part of an unselected, population-based study conducted in 2008. The treated subjects were prescribed primary/salvage external-beam RT to 70 Gy@2.0 Gy/fraction. Absorbed RT doses (Dmean and Dmax ) of the corpora cavernosa (CC), the penile bulb (PB), and the total penile structure (CC + PB) were related to 13 patient-reported symptoms on sexual dysfunction by means of factor analysis (FA) and logistic regression.

RESULTS

Three distinct symptom domains were identified across all cohorts: "erectile dysfunction" (ED, two to five symptoms), "orgasmic dysfunction" (OD, two to four symptoms), and "pain" (two to three symptoms). The strongest predictor for ED symptoms was CC + PB Dmax (P = 0.001-0.03), CC and PB Dmean predicted OD symptoms equally well (P = 0.03 and 0.02-0.05, respectively), and the strongest predictor for pain symptoms was CC + PB Dmean (P = 0.02-0.03).

CONCLUSION

Sexual dysfunction following RT was separated into three main domains with symptoms related to erectile dysfunction, orgasmic dysfunction, and pain. Chances for intact sexual functionality may be increased if dose to the total penile structure can be restricted for these domains in the planning of RT .

Combination Therapy Using Human Adipose-derived Stem Cells on the Cavernous Nerve and Low-energy Shockwaves on the Corpus Cavernosum in a Rat Model of Post-prostatectomy Erectile Dysfunction

OBJECTIVE

To investigate combined therapeutic efficacy of human adipose-derived stem cells (h-ADSCs) application on injured cavernous nerve and low-energy shockwave therapy (SWT) on the corpus cavernosum in a rat model of post-prostatectomy erectile dysfunction.

MATERIALS AND METHODS

Rats were randomly divided into 5 groups: control, bilateral cavernous nerve injury (BCNI), adipose-derived stem cell (ADSC) (BCNI group with h-ADSCs on the cavernous nerve), SWT (BCNI group with low-energy SWT on the corpus cavernosum), and ADSC/SWT (BCNI group with a combination of h-ADSCs and low-energy SWT). After 4 weeks, erectile function was assessed using intracavernosal pressure. The cavernous nerves and penile tissue were evaluated through immunostaining, Western blotting, and a cyclic guanosine monophosphate assay.

RESULTS

ADSC/SWT significantly improved intracavernosal pressure compared to the other experimental group. ADSC had significantly increased β-III tubulin expression of the cavernous nerve, and SWT had a markedly enhanced vascular endothelial growth factor expression in corpus cavernosum. The ADSC/SWT group had a significantly increased in alpha smooth muscle actin content (P < .05), neural nitric oxide synthase (nNOS) of the dorsal penile nerve (P < .05), endothelial nitric oxide synthase (eNOS) protein expression (P < .05), and cyclic guanosine monophosphate level (P < .05) compared to the ADSC or SWT alone group. In addition, ADSC/SWT reduces the apoptotic index in the corpus cavernosum.

CONCLUSION

In this study, h-ADSCs showed an effect on the recovery of injured cavernous nerve and low-energy SWT improved angiogenesis in the corpus cavernosum. The h-ADSCs combined with low-energy SWT showed beneficial effect on the recovery of erectile function in a rat model of postprostatectomy erectile dysfunction.

Impact of penile rehabilitation with low-dose vardenafil on recovery of erectile function in Japanese men following nerve-sparing radical prostatectomy

Erectile dysfunction (ED) is a major complication after radical prostatectomy (RP); however, debate continues regarding the efficacy of penile rehabilitation in the recovery of the postoperative erectile function (EF). This study included a total of 103 consecutive sexually active Japanese men with localized prostate cancer undergoing nerve-sparing RP, and analyzed the postoperative EF, focusing on the significance of penile rehabilitation. In this series, 24 and 79 patients underwent bilateral and unilateral nerve-sparing RPs, respectively, and 10 or 20 mg of vardenafil was administered to 35 patients at least once weekly, who agreed to undergo penile rehabilitation. Twelve months after RP, 48 (46.6%) of the 103 patients were judged to have recovered EF sufficient for sexual intercourse without any assistance. The proportion of patients who recovered EF in those undergoing penile rehabilitation (60.0%) was significantly greater than that in those without penile rehabilitation (38.2%). Of several parameters examined, the preoperative International Index of Erectile Function-5 (IIEF-5) score and nerve-sparing procedure were significantly associated with the postoperative EF recovery rates in patients with and without management by penile rehabilitation, respectively. Furthermore, univariate analysis identified the preoperative IIEF-5 score, nerve-sparing procedure and penile rehabilitation as significant predictors of EF recovery, among which the preoperative IIEF-5 score and nerve-sparing procedure appeared to be independently associated with EF recovery. Considering these findings, despite the lack of independent significance, penile rehabilitation with low-dose vardenafil could exert a beneficial effect on EF recovery in Japanese men following nerve-sparing RP.

Landmarks in erectile function recovery after radical prostatectomy

The description of the nerve-sparing technique of radical prostatectomy by Walsh was one of the major breakthroughs in the surgical treatment of prostate cancer in the 20(th) century. However, despite this advance and consequent technological refinements to nerve-sparing surgery, a large proportion of men still suffer from erectile dysfunction (ED) as a complication of prostatectomy. A plethora of therapeutic approaches have been proposed to optimize erectile function recovery in these patients. Several preclinical and translational studies have shown benefits of therapies including PDE5 inhibitor (PDE5I) treatment, immunomodulation, neurotrophic factor administration, and regenerative techniques, such as stem cell therapy, in animal models. However, most of these approaches have either failed to translate to clinical use or have yet to be studied in human subjects. Penile rehabilitation with PDE5Is is currently the most commonly used clinical strategy, in spite of the absence of solid clinical evidence to support its use.