Functional sequelae of cavernous nerve injury in the rat: is there model dependency

Vitamin D3 improved erectile function recovery by regulating autophagy and apoptosis in a rat model of cavernous nerve injury

Vitamin D3 is an important element in improving erectile function. However, the mechanisms of vitamin D3 remain unknown. Thus, we explored the effect of vitamin D3 on erectile function recovery after nerve injury in a rat model and investigated its possible molecular mechanisms. Eighteen male Sprague-Dawley rats were used in this study. The rats were randomly divided into three groups: the control, bilateral cavernous nerve crush (BCNC), and BCNC + vitamin D3 groups. BCNC model was established in rats by surgery. The intracavernosal pressure and the ratio of intracavernosal pressure to mean arterial pressure were utilized to evaluate erectile function. Masson trichrome staining, immunohistochemistry, terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling and western blot analysis were performed on penile tissues to elucidate the molecular mechanism. The results indicated that vitamin D3 alleviated hypoxia and suppressed the fibrosis signalling pathway by upregulating the expression of eNOS (p = 0.001), nNOS (p = 0.018) and α-SMA (p = 0.025) and downregulating the expression of HIF-1α (p = 0.048) and TGF-β1 (p = 0.034) in BCNC rats. Vitamin D3 promoted erectile function restoration by enhancing the autophagy process through decreases in the p-mTOR/mTOR ratio (p = 0.02) and p62 (p = 0.001) expression and increases in Beclin1 expression (p = 0.001) and the LC3B/LC3A ratio (p = 0.041). Vitamin D3 application improved erectile function rehabilitation by suppressing the apoptotic process through decreases in the expression of Bax (p = 0.002) and caspase-3 (p = 0.046) and an increase in the expression of Bcl2 (p = 0.004). Therefore, We concluded that vitamin D3 improved the erectile function recovery in BCNC rats by alleviating hypoxia and fibrosis, enhancing autophagy and inhibiting apoptosis in the corpus cavernosum.

The Cavernous Nerve Injury Rat Model: A Pictorial Essay on Post-Radical Prostatectomy Erectile Dysfunction Research

Understanding and addressing post-radical prostatectomy (RP) erectile dysfunction (ED) is of paramount importance for clinicians. Cavernous nerve (CN) injury rat model studies have provided consistently promising experimental data regarding regaining erectile function (EF) after nerve damage-induced ED. However, these findings have failed to translate efficiently into clinical practice, with post-RP ED therapeutic management remaining cumbersome and enigmatic. This disparity highlights the need for further standardization and optimization of the elaborate surgical preparation protocols and multifaceted reporting parameters involved in reliable CN injury rat model experimentation. Even so, despite its technical complexity, this animal model remains instrumental in exploring the functional implications of RP, i.e., surgical lesions of the neurovascular bundles (NVBs). Herein, besides cavernous nerve (CN) dissection, injury, and electrostimulation, multiple pressure measurements, i.e., mean arterial pressure (MAP) and intra-cavernosal pressure (ICP), must also be achieved. A transverse cervical incision allows for carotid artery cannulation and MAP measurements. Conversely, ICP measurements entail circumcising the penis, exposing the ischiocavernous muscle, and inserting a needle into the corporal body. Finally, using an abdominal incision, the prostate is revealed, and the major pelvic ganglia (MPG) and CNs are dissected bilaterally. Specific surgical techniques are used to induce CN injuries. Herein, we provide a narrative and illustrative overview regarding these complex experimental procedures and their particular requirements, reflecting on current evidence and future research perspectives.

Reviving intimacy: Penile rehabilitation strategies for men after prostate cancer treatment

There have been considerable advances in the field of penile rehabilitation for upwards of 90% of men adversely affected by either short-term or long-term erectile dysfunction after definitive prostate cancer treatment. Despite the evolving landscape of treatment modalities for penile rehabilitation, there is a lack of consensus in the urologic community on the best therapies due to the level of evidence and efficacies of the current and emerging offerings. This review of current and next-generation interventions provides a practical approach to the myriad of data to make a better-informed decision based on the pathophysiology and highest-quality evidence available.

Comparison of the efficacy of the early LI-SWT plus daily tadalafil with daily tadalafil only as penile rehabilitation for postprostatectomy erectile dysfunction

This study compares the efficacy of the early low-intensity shock wave therapy (LI-SWT) plus daily tadalafil with daily tadalafil only therapy as penile rehabilitation for postprostatectomy erectile dysfunction in patients with prostate cancer who underwent bilateral interfascial nerve-sparing radical prostatectomy (robotic or open). From April 2019 to March 2021, 165 patients were enrolled, and 80 of them successfully completed this prospective study. Daily tadalafil were administered to all the patients. LI-SWT consisted of a total of six sessions. Each session was performed on days 4, 5, 6, and 7, and on the second and fourth weeks after surgery. Each LI-SWT session consisted of 300 shocks at an energy density of 0.09 mJ/mm2 and a frequency of 120 shocks per minute that were delivered at each of the five treatment points for 15 min. Thirty-nine patients were treated with tadalafil-only (group A) while 41 were treated with tadalafil and LI-SWT simultaneously (group B). At postoperative 6 months, the proportion of patients with erection hardness scores (EHS) ≥ 3 (4/39 vs. 12/41) was significantly higher in group B (p = 0.034), and LI-SWT was the only independent factor for predicting EHS ≥ 3 (OR, 3.621; 95% CI, 1.054-12.437; p = 0.041). There were no serious side effects related to early LI-SWT. Early LI-SWT plus daily tadalafil therapy as penile rehabilitation for postprostatectomy erectile dysfunction is thought to be more efficacious than tadalafil only. Further large-scaled randomized controlled trials will be needed to validate these findings.

Rats, Neuregulins and Radical Prostatectomy: A Conceptual Overview

In the contemporary era of early detection, with mostly curative initial treatment for prostate cancer (PC), mortality rates have significantly diminished. In addition, mean age at initial PC diagnosis has decreased. Despite technical advancements, the probability of erectile function (EF) recovery post radical prostatectomy (RP) has not significantly changed throughout the last decade. Due to virtually unavoidable intraoperative cavernous nerve (CN) lesions and operations with younger patients, post-RP erectile dysfunction (ED) has now begun affecting these younger patients. To address this pervasive limitation, a plethora of CN lesion animal model investigations have analyzed the use of systemic/local treatments for EF recovery post-RP. Most promisingly, neuregulins (NRGs) have demonstrated neurotrophic effects in both neurodegenerative disease and peripheral nerve injury models. Recently, glial growth factor 2 (GGF2) has demonstrated far superior, dose-dependent, neuroprotective/restorative effects in the CN injury rat model, as compared to previous therapeutic counterparts. Although potentially impactful, these initial findings remain limited and under-investigated. In an effort to aid clinicians, our paper reviews post-RP ED pathogenesis and currently available therapeutic tools. To stimulate further experimentation, a standardized preparation protocol and in-depth analysis of applications for the CN injury rat model is provided. Lastly, we report on NRGs, such as GGF2, and their potentially revolutionary clinical applications, in hopes of identifying relevant future research directions.

The effect of pulsed radiofrequency application on nerve healing after sciatic nerve anastomosis in rats

The Effect of Pulsed Radiofrequency Application on Nerve Healing After Sciatic Nerve Anastomosis in Rats. In this study, we aimed to evaluate the histomorphological and functional effect of Pulsed Radiofrequency (PRF) application on regeneration after experimental nerve damage in rats. Forty Sprague-Dawley male rats were used in the study. Sciatic nerve incision was applied to all rats and then anastomosis was performed. Twenty rats were separated as the control group, and the remaining 20 rats underwent PRF every day at 42oC, for 120 seconds. The groups were divided into two further subgroups to be sacrificed on the 15th and 30th days. Tissue samples were obtained from all groups at 24 hours and 72 hours after the injury. Sections of sciatic nerve samples were stained with hematoxylin-eosin for light microscopic investigation and prepared for evaluation of ultrastructural changes with transmission electron microscopy. In the evaluation of axon numbers and diameters were seen that the 30th-day RF group had an increase compared to the control group. In the electron microscopic examination, it was observed that myelinated and unmyelinated nerve fiber sheaths had borders that are more regular in the RF group, the nucleus structures of schwann cells were better preserved, mitochondrial damage was less, and the extensions of fibroblast and collagen fibers were smoother than the control group. The findings suggested that PRF application has a positive contribution histologically on nerve healing in the early period after full-layer incision nerve injury anastomosis surgery.

The Role of Long Term Label-Retaining Cells in the Treatment of Erectile Dysfunction by Vacuum Erectile Device

Introduction

Vacuum erectile device (VED) therapy is commonly used for penile rehabilitation after radical prostatectomy, however, the underlying mechanism of this effect is not fully understood.

Aim

To evaluate the presence of label-retaining cells (LRCs), cells with long-term retention of 5-ethynyl-2-deoxyuridine (EdU) labeling and recognized as adult stem cells or progenitor-like cells, in cavernous tissue after VED treatment using a BCNC rat model.

Methods

Postnatal pups (1 day old) of Sprague Dawley (SD) rats were intraperitoneally injected with EdU (50 ug/g, BID for 3 days) and BCNC surgery was conducted at 6 weeks old (designated as natal-labeled rats). Adult SD rats underwent BCNC surgery and EdU injection (50 ug/g, once) after surgery (designated as adult-labeled rats). One week after surgery, both natal- and adult-labeled rats received daily VED treatment for 4 weeks. Intracavernous pressure (ICP) and mean arterial pressure (MAP) were measured for all rats and then the penile tissue was harvested. The ratio of ICP/MAP was calculated to represent erectile function. Penile tissue was examined by immunofluorescence staining to detect EdU positive cells.

Main Outcome Measures

The ratio of Intracavernous pressure (ICP) /MAP and the percentage of EdU positive cells were measured.

Results

The erectile function was impaired after BCNC and partially restored after VED treatment in both natal- and adult-labeled rats (P < .05). There was no difference in the percentage of EdU positive cells in natal-labeled rat cavernous tissue in BCNC group compared with VED group. Among the adult-labeled rats, the percentage of EdU positive cells increased in BCNC group (P < .05) but didn't change significantly after VED treatment (P = .35).

Conclusion

LRCs may play a limited role in the restoration of erectile dysfunction through VED treatment after BCNC.

Yang B, Luse D, Cao Y, et al. The Role of Long Term Label-Retaining Cells in the Treatment of Erectile Dysfunction by Vacuum Erectile Device. Sex Med 2021;9:100442.

Peptide amphiphile nanofiber hydrogel delivery of Sonic hedgehog protein to the penis and cavernous nerve suppresses intrinsic and extrinsic apoptotic signaling mechanisms, which are an underlying cause of erectile dysfunction

Erectile dysfunction (ED) is a common and debilitating condition with high impact on quality of life. An underlying cause of ED is apoptosis of penile smooth muscle, which occurs with cavernous nerve injury, in prostatectomy, diabetic and aging patients. We are developing peptide amphiphile (PA) nanofiber hydrogels as an in vivo delivery vehicle for Sonic hedgehog protein to the penis and cavernous nerve to prevent the apoptotic response. We examine two important aspects required for clinical application of the biomaterials: if SHH PA suppresses intrinsic (caspase 9) and extrinsic (caspase 8) apoptotic mechanisms, and if suppressing one apoptotic mechanism forces apoptosis to occur via a different mechanism. We show that SHH PA suppresses both caspase 9 and 8 apoptotic mechanisms, and suppressing caspase 9 did not shift signaling to caspase 8. SHH PA has significant clinical potential as a preventative ED therapy, by management of intrinsic and extrinsic apoptotic mechanisms.

Optimal vacuum erectile device therapy regimen for penile rehabilitation in a bilateral cavernous nerve crush rat model

BACKGROUND

Vacuum erectile device (VED) therapy has been widely used in penile rehabilitation after radical prostatectomy; however, there is no consensus on the best regimen.

OBJECTIVES

To explore an optimal VED therapy regimen in bilateral cavernous nerve crush (BCNC) rat model.

MATERIALS AND METHODS

Adult male rats were used to measure the effects of different durations (1-30 min) of VED treatment on penile length, penile blood gas analysis, and adverse effects. Forty-eight adult male rats were randomly divided into Sham, BCNC, and VED treatment groups (2-3-2-3 min, 4-3-3 min, 5-5 min, and 10 min). Penile length, erectile function, and side effects were detected after VED treatment. Histopathological staining and Western blotting were performed to explore the cellular and molecular changes.

RESULTS

Prolongation of the duration of VED treatment significantly decreased the penile oxygen saturation, partial oxygen pressure, and arterial blood ratio (P < 0.05). Compared with the BCNC group, all VED treatment regimens partially reversed BCNC-induced penile shortening and erectile dysfunction (P < 0.0001), with the 4-3-3-min and 5-5-min treatment groups exhibiting more significant improvement than the 10-min and 2-3-2-3-min treatment groups (P < 0.0001). The mechanism may be related to the up-regulation of the smooth muscle cell/collagen ratio, endothelial nitric oxide synthase, and α-smooth muscle actin (all P < 0.0001); and the down-regulation of hypoxia-inducible factor-1α, transforming growth factor-β1, and apoptosis (all P < 0.0001). The incidence of adverse effects in the 2-3-2-3-min treatment group was the highest.

DISCUSSION

The commonly used VED therapy regimens maintained erectile function and penile length of BCNC rat by relieving hypoxia and fibrosis, and no further benefits were observed with increased treatment frequency or prolonged treatment duration.

CONCLUSION

Two consecutive 5-min treatments with a short interval is the optimal VED therapy regimen for penile rehabilitation in BCNC rat model.

Vacuum therapy ameliorates erectile dysfunction in bilateral cavernous nerve crush rats by inhibiting apoptosis and activating autophagy

Postprostatectomy erectile dysfunction (pPED) remains a current problem despite improvements in surgical techniques. Vacuum therapy is clinically confirmed as a type of pPED rehabilitation. However, its underlying mechanisms are incompletely understood. Recently, autophagy and apoptosis were extensively studied in erectile dysfunction resulting from diabetes, senescence, and androgen deprivation but not in the context of pPED and vacuum therapy. Therefore, this study was designed to investigate the roles of autophagy and apoptosis in pPED and vacuum therapy. Twenty-four adult male Sprague-Dawley rats were randomly divided into three groups: the control group, bilateral cavernous nerve crush (BCNC) group, and BCNC + vacuum group. After 4 weeks of treatment, intracavernosal pressure was used to evaluate erectile function. Real-time quantitative polymerase chain reaction, western blot, and immunohistochemistry were used to measure the molecular expression. TdT-mediated dUTP nick-end labeling staining was used to assess apoptosis. Transmission electron microscopy was used to observe autophagosomes. After treatment, compared with those of the BCNC group, erectile function and cavernosal hypoxia had statistically significantly improved (P < 0.05). Apoptosis and the relative protein expression of B-cell lymphoma-2-associated X and cleaved Caspase3 were decreased (P < 0.05). Autophagy-related molecules such as phosphorylated unc-51-like autophagy-activating kinase 1 (Ser757) and p62 were decreased. Beclin1, microtubule-associated protein 1 light chain 3 A/B, and autophagosomes were increased (P < 0.05). Besides, the phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin signaling pathway, as a negative regulator of autophagy to some degree, was inhibited. This study revealed that vacuum therapy ameliorated pPED in BCNC rats by inhibiting apoptosis and activating autophagy.

The effect of erythropoietin and umbilical cord-derived mesenchymal stem cells on nerve regeneration in rats with sciatic nerve injury

OBJECTIVE

We aimed to investigate the effects of umbilical cord-derived mesenchymal stem cells and erythropoietin on nerve regeneration in the sciatic nerve 'crush injury' in a rat model.

METHODS

Experimental animals were randomly divided into 5 groups: Crush Injury, Sham, Crush Injury + Erythropoietin, Crush Injury + Mesenchymal Stem Cell, Crush Injury + Erythropoietin + Mesenchymal Stem Cell groups. Crush injury made with bulldog clamp. Mesencyhmal stem cells delivered by enjection locally. Erythropoietin administered by intraperitoneally. On the 0th, 14th and 28th days, all groups underwent a sciatic functional index test. On 28th day, sciatic nerves were harvested and histopathological appearance, axon number and axon diameter of the sciatic nerves were evaluated with Oil Red O staining. Immunoreactivity of nerve growth factor, neurofilament-H and caspase-3 were determined by immunofluorescence staining in nerve tissue.

RESULTS

In histopathological examination, axons and nerve bundles exhibiting normal nerve architecture in the Sham group. Crush Injury + Mesenchymal Stem Cell group has similar histological appearance to the Sham group. The number of axons were higher in the Mesenchymal Stem Cell groups compared to the Crush Injury group. Nerve growth factor immunoreactivity intensity was significantly lower in Crush Injury + Mesenchymal Stem Cell group compared to Crush Injury group. Neurofilament-H density was higher in the treatment groups when compared to the Crush Injury group.

CONCLUSIONS

In this study, it was found that umbilical cord-derived mesenchymal stem cells and erythropoietin treatments effects positively regeneration of crush injury caused by bulldog clamp in the sciatic nerve of rats.

Caspase Signaling in ED Patients and Animal Models

BACKGROUND

Current treatments for erectile dysfunction (ED) are ineffective in prostatectomy and diabetic patients due to cavernous nerve (CN) injury, which causes smooth muscle apoptosis, penile remodeling, and ED. Apoptosis can occur via the intrinsic (caspase 9) or extrinsic (caspase 8) pathway.

AIM

We examined the mechanism of how apoptosis occurs in ED patients and CN injury rat models to determine points of intervention for therapy development.

METHODS AND OUTCOMES

Immunohistochemical and western analyses for caspase 3-cleaved, caspase-8 and caspase-9 (pro and active forms) were performed in corpora cavernosal tissue from Peyronie's, prostatectomy and diabetic ED patients (n = 33), penis from adult Sprague Dawley rats that underwent CN crush (n = 24), BB/WOR diabetic and control rats (n = 8), and aged rats (n = 9).

RESULTS

Caspase 3-cleaved was observed in corpora cavernosa from Peyronie's patients and at higher abundance in prostatectomy and diabetic tissues. Apoptosis takes place primarily through the extrinsic (caspase 8) pathway in penis tissue of ED patients. In the CN crushed rat, caspase 3-cleaved was abundant from 1-9 days after injury, and apoptosis takes place primarily via the intrinsic (caspase 9) pathway. Caspase 9 was first observed and most abundant in a layer under the tunica, and after several days was observed in the lining of and between the sinuses of the corpora cavernosa. Caspase 8 was initially observed at low abundance in the rat corpora cavernosa and was not observed at later time points after CN injury. Aged and diabetic rat penis primarily exhibited intrinsic mechanisms, with diabetic rats also exhibiting mild extrinsic activation.

CLINICAL TRANSLATION

Knowing how and when to intervene to prevent the apoptotic response most effectively is critical for the development of drugs to prevent ED, morphological remodeling of the corpora cavernosa, and thus, disease management.

STRENGTHS AND LIMITATIONS

Animal models may diverge from the signaling mechanisms observed in ED patients. While the rat utilizes primarily caspase 9, there is a significant flux through caspase 8 early on, making it a reasonable model, as long as the timing of apoptosis is considered after CN injury.

CONCLUSIONS

Apoptosis takes place primarily through the extrinsic caspase 8 dependent pathway in ED patients and via the intrinsic caspase 9 dependent pathway in commonly used CN crush ED models. This is an important consideration for study design and interpretation that must be taken into account for therapy development and testing of drugs, and our therapeutic targets should ideally inhibit both apoptotic mechanisms. Martin S, Harrington DA, Ohlander S, et al. Caspase Signaling in ED Patients and Animal Models. J Sex Med 2021;18:711-722.

N-acetylcysteine maintains penile length and erectile function in bilateral cavernous nerve crush rat model by reducing penile fibrosis

Penile length shortening and erectile dysfunction are common complications after radical prostatectomy. Various methods have been used to maintain erectile function, but less attention has been paid to preserving penis length. N-acetylcysteine (NAC) has the effect of antioxidation and antifibrotic, which may be beneficial to improve those postoperative complications. This study investigated the effect of NAC on maintaining the penile length and the erectile function after bilateral cavernous nerve crush (BCNC) and its underlying mechanism. Twenty-four male rats were randomly divided into three groups: control group, BCNC group, and BCNC + NAC group. NAC or equal volume of saline was daily administrated by intragastric gavage for 4 weeks. The initial and end penile lengths were measured. Intracavernosal pressure/mean arterial pressure (ICP/MAP) ratio was calculated to assess erectile function. Hematoxylin–eosin staining, Masson's trichrome staining, immunohistochemistry, and Western blot were performed to explore cellular and molecular changes of the penis. Compared to the BCNC group, the penile length, ICP/MAP ratio and smooth muscle/collagen ratio in the BCNC + NAC group were improved significantly (all P < 0.05), and the expressions of endothelial nitric oxide synthase, α-smooth muscle actin, glutathione, and glutathione peroxidase 1 were significantly increased after NAC treated (all P < 0.05), along with the decreased expressions of hypoxia-inducible factor-1α, transforming growth factor-β1, collagen I, collagen III, collagen IV, malonaldehyde, and lysine oxidase (all P < 0.05). This study demonstrated that NAC could maintain penile length and partly improve erectile function. Possible mechanism is directly and/or indirectly related to antihypoxic and antifibrosis.

Optimal pressure in penile rehabilitation with a vacuum erection device: evidence based on a rat model

Vacuum erection device (VED), used to treat radical prostatectomy (RP)-associated erectile dysfunction, has attracted considerable attention. However, the optimal negative pressure remains to be determined. This investigation explored the optimal pressure for VED therapy in penile rehabilitation. Thirty-six 9-week-old male rats were randomly divided into six groups: control groups (sham group, bilateral cavernous nerve crush [BCNC] group) and VED therapy groups (−200 mmHg group, −300 mmHg group, −400 mmHg group, −500 mmHg group). BCNC group and VED therapy groups underwent BCNC surgery. Intracavernosal pressure (ICP)/mean arterial pressure (MAP) ratio was calculated to assess erectile function. Masson's trichrome (MT) staining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, immunohistochemistry, and real-time polymerase chain reaction (RT-PCR) were performed to explore cellular and molecular changes of the penis. Compared to the BCNC group, ICP/MAP ratios in all VED treatment groups were improved significantly (all P < 0.05), but there were no statistically significant differences among VED therapy groups. With increased pressure, complications gradually emerged and increased in frequency. Expression of molecular indicators, such as endothelial nitric oxide synthase (eNOS) and alpha-smooth muscle actin (α-SMA), increased after VED therapy, and hypoxia-inducible factor 1α (HIF-1α) and transforming growth factor beta (TGF-β) decreased. In addition, VED therapy improved the outcomes of MT and TUNEL assay. This investigation demonstrated a pressure of −200 mmHg in a rat model is optimal for VED therapy for penile rehabilitation after RP. No further benefits were observed with increased pressure, despite an increase in complications.

European Society for Sexual Medicine Consensus Statement on the Use of the Cavernous Nerve Injury Rodent Model to Study Postradical Prostatectomy Erectile Dysfunction

INTRODUCTION

Rodent animal models are currently the most used in vivo model in translational studies looking into the pathophysiology of erectile dysfunction after nerve-sparing radical prostatectomy.

AIM

This European Society for Sexual Medicine (ESSM) statement aims to guide scientists toward utilization of the rodent model in an appropriate, timely, and proficient fashion.

METHODS

MEDLINE and EMBASE databases were searched for basic science studies, using a rodent animal model, looking into the consequence of pelvic nerve injury on erectile function.

MAIN OUTCOME MEASURES

The authors present a consensus on how to best perform experiments with this rodent model, the details of the technique, and highlight possible pitfalls.

RESULTS

Owing to the specific issue-basic science-Oxford 2011 Levels of Evidence criteria cannot be applied. However, ESSM statements on this topic will be provided in which we summarize the ESSM position on various aspects of the model such as the use of the Animal Research Reporting In Vivo Experiments guideline and the of common range parameter for nerve stimulation. We also highlighted the translational limits of the model.

CONCLUSION

The following statements were formulated as a suggestive guidance for scientists using the cavernous nerve injury model. With this, we hope to standardize and further improve the quality of research in this field. It must be noted that this model has its limitations. Weyne E, Ilg MM, Cakir OO, et al. European Society for Sexual Medicine Consensus Statement on the Use of the Cavernous Nerve Injury Rodent Model to Study Postradical Prostatectomy Erectile Dysfunction. Sex Med 2020;8:327-337.

Melatonin prevents deterioration of erectile function in streptozotocin-induced diabetic rats via sirtuin-1 expression

A review of the literature indicated that sirtuin-1 expression, a regulator of nitric oxide bioavailability in erectile dysfunction (ED) after melatonin therapy, has not yet been investigated. The objective of this study was to evaluate the protective effects of melatonin for erectile function with sirtuin-1 protein expression in type 1 diabetic rat models. Fifty male Sprague Dawley rats were placed into five groups. Except for those in the control group (C), each animal received a single dose (60 mg/kg) of streptozotocin to induce diabetes. The animals were placed into the diabetes (D) group, insulin (I) group (6 U/kg/day), melatonin (Mel) group (10 mg kg^-1  day^-1 ) and combined treatment (I + Mel) group. Ten weeks later, the serum testosterone levels, intracavernosal pressure (ICP), mean arterial pressure (MAP), malondialdehyde (MDA), cyclic guanosine monophosphate (c-GMP), 8-hydroxydeoxyguanosine (8-OHdG), nitric oxide synthase (NOS), caspase-3 activity, sirtuin-1 and endothelial nitric oxide synthase (eNOS) protein expression and histological findings were assessed. The mean ICP/MAP ratio for the D group was lower than the mean ratios for the other groups. The treatment groups, particularly the I + Mel group, exhibited lower 8-OHdG and MDA levels and caspase-3 activity than the D group. The sirtuin-1 and eNOS expression and cavernosal tissue (CT) histology seemed to have been preserved by the melatonin and/or insulin therapy. These results were indicative of a profound protective effect of melatonin by the activation of sirtuin-1 protein expression against hyperglycemia-induced oxidative CT injury.

Vacuum therapy prevents corporeal veno-occlusive dysfunction and penile shrinkage in a cavernosal nerve injured rat model

Erectile dysfunction and penile shrinkage are the common complications after radical prostatectomy. Penile rehabilitation is widely applied after the surgery. Vacuum therapy is one of the three penile rehabilitation methods used in the clinical setting, but its mechanism is not well known. This study was designed to investigate whether vacuum erectile device (VED) can prevent corporeal veno-occlusive dysfunction and penile shrinkage in the bilateral cavernous nerve crush (BCNC) rat model. Adult male Sprague-Dawley rats were randomly assigned into three groups: sham group, BCNC group, and BCNC + VED group. After 4 weeks, penile length and intracavernosal pressure (ICP) were measured, and then the middle part of the penis was harvested after dynamic infusion cavernosometry to complete the following items: smooth muscle/collagen ratios and collagen I/III ratios; ultramicrostructure of the tunica albuginea, endothelial cell, and smooth muscle cell; and the expression of calponin-1 and osteopontin. The penile shortening, peak ICP and ICP drop rate after alprostadil injection were significantly improved with vacuum therapy after 4-week treatment. Compared with BCNC group, VED significantly increased smooth muscle/collagen ratios, decreased collagen I/III ratios, and preserved the ultramicrostructure of the tunica albuginea, endothelial cell, and smooth muscle cell. The data also showed that animals exposed to VED could partially reverse the expression of calponin-1 and osteopontin induced by BCNC. In conclusion, vacuum therapy is effective to prevent penile shrinkage and veno-occlusive dysfunction in penile rehabilitation, which may be associated with well-preserved structure and function of the tunica albuginea, endothelial cell, and smooth muscle cell.

Nanotechnology-assisted adipose-derived stem cell (ADSC) therapy for erectile dysfunction of cavernous nerve injury: In vivo cell tracking, optimized injection dosage, and functional evaluation

Stem cell therapy is a potentially promising option for erectile dysfunction; however, its risk of tumorigenicity is a clinical hurdle and the risk is positively related to the number of injected cells. Our previous study showed that nanotechnology improved adipose-derived stem cell (ADSC) therapy for erectile dysfunction of cavernous nerve injury (CNI) by attracting cells in the corpus cavernosum. These results indicated the possibility of using a reduced dosage of ADSCs for intracavernous injection. In this exploratory study, we used lower dosage (2 × 10⁵ cells) of ADSCs for intracavernous injection (ICI) and the nanotechnology approach. Intracavernous pressure and mean arterial pressure were measured at day 28 to assess erectile function. The low-dose ADSC therapy group showed favorable treatment effects, and nanotechnology further improved these effects. In vivo imaging of ICI cells revealed that the fluorescein signals of NanoShuttle-bound ADSCs (NanoADSCs) were much stronger than those of ADSCs at days 0, 1, and 3. Both immunofluorescence and Western blot analysis showed a significant increase in smooth muscle, endothelium, and nerve tissue in the ADSC group compared to that in the CNI group; further improvement was achieved with assisted nanotechnology. These findings demonstrate that nanotechnology can be used to further improve the effect of small dosage of ADSCs to improve erectile function. Abundant NanoADSCs remain in the corpus cavernosum in vivo for at least 3 days. The mechanism of erectile function improvement may be related to the regeneration of the smooth muscle, endothelium, and nerve tissues.

Role of inhibiting LIM-kinase2 in improving erectile function through suppression of corporal fibrosis in a rat model of cavernous nerve injury

We evaluated whether LIM-kinase 2 inhibitor (LIMK2i) could improve erectile function by suppressing corporal fibrosis through the normalization of the Rho-associated coiled-coil protein kinase 1 (ROCK1)/LIMK2/Cofilin pathway in a rat model of cavernous nerve crush injury (CNCI). Sixty 11-week-old male Sprague-Dawley rats were divided equally into five groups: sham surgery (S), CNCI (I), and CNCI treated with low-dose (L), medium-dose (M), and high-dose (H) LIMK2i. The L, M, and H groups were treated with a daily intraperitoneal injection of LIMK2i (2.5, 5.0, and 10.0 mg kg^-1 body weight, respectively) for 1 week after surgery. The erectile response was assessed using electrostimulation at 1 week, postoperatively. Penile tissues were processed for Masson's trichrome staining, double immunofluorescence, and Western blot assay. Erectile responses in the H group improved compared with the I group, while the M group showed only partial improvement. A significantly decreased smooth muscle/collagen ratio and an increased content of fibroblasts positive for phospho-LIMK2 were noted in the I group. The M and H groups revealed significant improvements in histological alterations and the dysregulated LIMK2/Cofilin pathway, except for LIMK2 phosphorylation in the M group. The inhibition of LIMK2 did not affect the ROCK1 protein expression. The content of fibroblasts positive for phospho-LIMK2 in the H group returned to the level found in the S group, whereas it did not in the M group. However, the L group did not exhibit such improvements. Our data suggest that the inhibition of LIMK2, particularly with administration of 10.0 mg kg^-1 body weight LIMK2i, can improve corporal fibrosis and erectile function by normalizing the LIMK2/Cofilin pathway.

Optimization of Sonic Hedgehog Delivery to the Penis from Self-Assembling Nanofiber Hydrogels to Preserve Penile Morphology after Cavernous Nerve Injury

Erectile dysfunction (ED) is a significant medical condition, with high impact on patient quality of life. Current treatments are minimally effective in prostatectomy, diabetic and aging patients due to injury to the cavernous nerve (CN); loss of innervation causes extensive smooth muscle (SM) apoptosis, increased collagen and ED. Sonic hedgehog (SHH) is a critical regulator of penile SM. We developed a self-assembling peptide amphiphile (PA) nanofiber hydrogel for extended release of SHH protein to the penis after CN injury, to suppress SM apoptosis. In this study we optimize the animal model, SHH concentration, duration of suppression, and location of delivery, to maximize SM preservation. SHH treatment suppressed apoptosis and preserved SM 48%. Increased SHH duration preserved SM 100%. Simultaneous penis/CN delivery increased SM 127%. Optimization of SHH PA delivery is essential for clinical translation to ED patients, and the PA vehicle has wide applicability as an in vivo delivery tool.

MicroRNA-141 binds to the nerve growth factor receptor associated protein 1 gene and restores the erectile function of diabetic rats through down-regulating the nerve growth factor/neurotrophin receptor p75 (NGF/p75NTR) signaling

BACKGROUND

Erectile dysfunction (ED) is one of the major complications in diabetes mellitus (DM). We have previously reported that the nerve growth factor (NGF)/tyrosine kinase receptor (TrkA) signaling is actively involved in DM-induced ED (DMED). Here, we investigate the effect of micro-RNA-141 (miR-141) on the NGF/p75 neurotrophin receptor (p75NTR) signaling and erectile function of diabetic rats.

METHODS

Sprague-Dawlay (SD) rats were used to establish a DMED model. The dual-luciferase reporter gene assay was first performed to identify the nerve growth factor receptor-associated protein 1 (NGFRAP1) gene as the target gene of miR-141. The regulatory mechanisms underlying miR-141 governing NGFRAP1 in vivo were then validated by modulating the expressions of miR-141 and knocking down NGFRAP1.

RESULTS

The expressions of miR-141 were decreased while the expressions of NGFRAP1, NGF, and p75NTR were increased in DMED. miR-141 and downregulation of NGFRAP1, respectively, increased the density of corpus cavernosum smooth muscle and the ratio of intracavernosal pressure (ICP)/mean arterial blood pressure (MAP) and promoted the expression of α-actin and desmin as well. miR-141 also upregulated the expressions of NGFRAP1 in DMED, and knockdown of NGFRAP1 inhibited the productions of NGF and p75NTR. Furthermore, miR-141 suppressed the NGF/p75NTR signaling via binding to NGFRAP1.

CONCLUSIONS

NGF/p75NTR signaling actively participates in the pathogenesis of DMED. miR-141 binds to NGFRAP1 and restores the erectile function of diabetic rats via downregulation of NGF/p75NTR signaling.

Pelvic and hypogastric nerves are injured in a rat prostatectomy model, contributing to development of stress urinary incontinence

Urinary incontinence affects 40% of elderly men, is common in diabetic patients and in men treated for prostate cancer, with a prevalence of up to 44%. Seventy-two percent of prostatectomy patients develop stress urinary incontinence (SUI) in the first week after surgery and individuals who do not recover within 6 months generally do no regain function without intervention. Incontinence has a profound impact on patient quality of life and a critical unmet need exists to develop novel and less invasive SUI treatments. During prostatectomy, the cavernous nerve (CN), which provides innervation to the penis, undergoes crush, tension, and resection injury, resulting in downstream penile remodeling and erectile dysfunction in up to 85% of patients. There are other nerves that form part of the major pelvic ganglion (MPG), including the hypogastric (HYG, sympathetic) and pelvic (PN, parasympathetic) nerves, which provide innervation to the bladder and urethra. We examine if HYG and PNs are injured during prostatectomy contributing to SUI, and if Sonic hedgehog (SHH) regulatory mechanisms are active in the PN and HYG nerves. CN, PN, HYG and ancillary (ANC) of uninjured, sham and CN crush/MPG tension injured (prostatectomy model) adult Sprague Dawley rats (n = 37) were examined for apoptosis, sonic hedgehog (SHH) pathway, and intrinsic and extrinsic apoptotic mechanisms. Fluorogold tracing from the urethra/bladder was performed. PN and HYG response to SHH protein was examined in organ culture. TUNEL, immunohistochemical analysis for caspase-3 cleaved, -8, -9, SHH, Patched and Smoothened (SHH receptors), and neurite formation, were examined. Florogold positive neurons in the MPG were reduced with CN crush. Apoptosis increased in glial cells of the PN and HYG after CN crush. Caspase 9 was abundant in glial cells (intrinsic), while caspase-8 was not observed. SHH and its receptors were abundant in neurons and glia of the PN and HYG. SHH treatment increased neurite formation. PN and HYG injury occur concomitant with CN injury during prostatectomy, likely contributing to SUI. PN and HYG response to SHH treatment indicates an avenue for intervention to promote regeneration and prevent SUI.

Sonic hedgehog regulation of cavernous nerve regeneration and neurite formation in aged pelvic plexus

INTRODUCTION

Erectile dysfunction (ED) is a significant health concern that greatly impacts quality of life, and is common in men as they age, impacting 52% of men between the ages of 40 and 70. A significant underlying cause of ED development is injury to the cavernous nerve (CN), a peripheral nerve that innervates the penis. CN injury also occurs in up to 82% of prostatectomy patients. We recently showed that Sonic hedgehog (SHH) protein delivered by peptide amphiphile (PA) nanofiber hydrogel to the CN and penis of a prostatectomy model of CN injury, is neuroprotective, accelerates CN regeneration, improves erectile function ~60%, preserves penile smooth muscle 56% and suppresses collagen deposition 30%. This regenerative potential is substantial in an adult prostatectomy model (P120). However prostatectomy patients are typically older (61.5 ± 9.6 years) and our models should mimic patient conditions more effectively when considering translation. In this study we examine regenerative potential in an aged prostatectomy model (P200-329).

METHODS

The caudal portion of the pelvic ganglia (MPG) and CN were dissected from adult (n = 11), and aged (n = 13) Sprague Dawley rats, and were grown in organ culture 3 days. Uninjured and 2 day CN crushed MPG/CN were exposed to Affi-Gel beads containing SHH protein, PBS (control), or 5e1 SHH inhibitor. Neurites were quantified by counting the number of growth cones normalized by tissue perimeter (mm) and immunohistochemistry for SHH, patched1 (PTCH1), smoothened (SMO), GLI1-3, and GAP43 were performed.

RESULTS

SHH treatment increased neurites 3.5-fold, in uninjured adult, and 5.7-fold in aged rats. Two days after CN crush, SHH treatment increased neurites 1.8-fold in adult rats and 2.5-fold in aged rats. SHH inhibition inhibited neurite formation in uninjured MPG/CN but not in 2 day CN crushed MPG/CN. PTCH1 and SMO (SHH receptors), and SHH transcriptional activators/repressors, GLI1-3, were abundant in aged MPG/CN with unaltered localization. ROCK1 was induced with SHH treatment.

CONCLUSIONS

Reintroduction of SHH protein in an aged prostatectomy model is even more effective in promoting neurite formation/CN regeneration than in the adult. The first 48 h after CN injury are a critical window when growth factors are released, that impact later neurite formation. These studies are significant because most prostatectomy patients are not young and healthy, as with adult rats, so the aged prostatectomy model will more accurately simulate ED patient response. Understanding how neurite formation changes with age is critical for clinical translation of SHH PA to prostatectomy patients.

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.

Strategies to improve nerve regeneration after radical prostatectomy: a narrative review

Peripheral nerves are complex organs that spread throughout the entire human body. They are frequently affected by lesions not only as a result of trauma but also following radical tumor resection. In fact, despite the advancement in surgical techniques, such as nerve-sparing robot assisted radical prostatectomy, some degree of nerve injury may occur resulting in erectile dysfunction with significant impairment of the quality of life. The aim of this review was to provide an overview on the mechanisms of the regeneration of injured peripheral nerves and to describe the potential strategies to improve the regeneration process and the functional recovery. Yet, the recent advances in bio-engineering strategies to promote nerve regeneration in the urological field are outlined with a view on the possible future regenerative therapies which might ameliorate the functional outcome after radical prostatectomy.

Resveratrol treatment may preserve the erectile function after radiotherapy by restoring antioxidant defence mechanisms, SIRT1 and NOS protein expressions

Radiotherapy (RT) for prostate cancer (PC) can cause erectile dysfunction (ED) by damaging neurovascular structures with oxidative stress. In this study, we evaluated the effects of resveratrol, an antioxidant, on post-RT ED. Fifty rats in five groups were evaluated; control (C), prostate-confined radiotherapy with short- and long-term vehicle or resveratrol treatment. Cavernosal tissues were obtained to analyze glutathione (GSH), nitric oxide (NO), cyclic guanosine monophosphate (cGMP), 8-hydroxy-2'-deoxy-guanosine (8-OHdG) levels and superoxide dismutase (SOD), caspase-3 activities, sirtuin-1, Foxo-3, nNOS, and eNOS protein expressions. Intracavernosal pressures (ICP) were measured for the long-term treatment group. In the RT + long-term vehicle treatment group, tissue GSH, NO, cGMP, and SOD activity were decreased while 8-OHdg levels and caspase-3 activities were increased. Radiotherapy caused a decrease in sirtuin-1, nNOS, and eNOS protein expressions. These parameters were reversed by resveratrol treatment. Foxo-3 protein expressions were unaltered in the RT + short-term vehicle treatment group and started to increase as a defense mechanism in the RT + long-term vehicle group; however, resveratrol treatment caused a significant increase in Foxo-3 expressions. Resveratrol preserved the metabolic pathways involved in erectile function and provided functional protection. Resveratrol can be used as a supplementary agent in patients undergoing radiotherapy to preserve erectile function.

Peptide amphiphile delivery of sonic hedgehog protein promotes neurite formation in penile projecting neurons

Erectile dysfunction (ED) critically impacts quality of life in prostatectomy, diabetic and aging patients. The underlying mechanism involves cavernous nerve (CN) damage, resulting in ED in 80% of prostatectomy patients. Peptide amphiphile (PA) nanofiber hydrogel delivery of sonic hedgehog (SHH) protein to the injured CN, improves erectile function by 60% at 6 weeks after injury, by an unknown mechanism. We hypothesize that SHH is a regulator of neurite formation. SHH treatment promoted extensive neurite formation in uninjured and crushed CNs, and SHH inhibition decreased neurites >80%. Most abundant neurites were observed with continuous SHH PA treatment of crushed CNs. Once induced with SHH, neurites continued to grow. SHH rescued neurite formation when not given immediately. SHH is a critical regulator of neurite formation in peripheral neurons under uninjured and regenerative conditions, and SHH PA treatment at the time of injury/prostatectomy provides an exploitable avenue for intervention to prevent ED.

Efficacy and Safety of Tadalafil 5 mg Once Daily for the Treatment of Erectile Dysfunction After Robot-Assisted Laparoscopic Radical Prostatectomy: A 2-Year Follow-Up

BACKGROUND

Although nerve-sparing robot-assisted radical prostatectomy (NS-RALP) is performed, a large number of patients still experience erectile dysfunction (ED) after surgery.

AIM

To evaluate the efficacy and safety of tadalafil 5 mg once daily (OaD) in ED treatment over 2 years and investigate the cause of vascular ED after NS-RARP.

METHODS

We retrospectively evaluated 95 men who underwent NS-RARP and had a penile rehabilitation treatment with tadalafil 5 mg OaD. They were classified into 3 groups: tadalafil 5 mg OaD for 2 years (group I), tadalafil 5 mg OaD for 1 year (group II), and no tadalafil (group III). All patients in group I underwent penile color duplex ultrasound to evaluate the cause of vascular ED.

OUTCOMES

Patients were surveyed using the abridged 5-item International Index of Erectile Function (IIEF-5).

RESULTS

Statistically significant improvements were observed in group I for all IIEF-5 domain scores (P = .000). There was no statistically significant difference in recovery of erectile function (EF) the 2-year follow-up between groups I and II. Sub-analysis based on NS status showed no difference in recovery of EF. However, group I showed better trends in EF improvement. Those with venogenic ED had poor responses compared with those with arteriogenic ED or unremarkable findings with tadalafil 5-mg OaD treatment (14.2% vs 55.0% vs 53.3%). The overall side effects included hot flushing in 9.5%, headache in 7.1%, and dizziness in 2.3% of patients.

CLINICAL IMPLICATIONS

Long-term usage of tadalafil 5 mg OaD after RARP can be an effective option for penile rehabilitation.

STRENGTHS AND LIMITATIONS

The present study is a retrospective study with a relatively small sample.

CONCLUSIONS

Although the responses of patients with venogenic ED were limited compared with those with arteriogenic ED, tadalafil 5-mg OaD treatment was well tolerated and significantly improved EF up to 2 years after NS-RARP. Kim S, Sung GT. Efficacy and Safety of Tadalafil 5 mg Once Daily for the Treatment of Erectile Dysfunction After Robot-Assisted Laparoscopic Radical Prostatectomy: A 2-Year Follow-Up. Sex Med 2018;6:108-114.

Cavernous Nerve Stimulation and Recording of Intracavernous Pressure in a Rat

The stimulation of the cavernous nerve (CN) and measurement of intracavernous pressure (ICP) have been used extensively to test and evaluate therapies for erectile dysfunction. However, the methods used vary between laboratories, and pitfalls still exist. The goal of this study was to describe a surgical technique that would provide a reliable and reproducible model. By exposing the ischiocavernosus muscle at its point of insertion on the ischial tuberosity, the penile crus could be cannulated with minimal dissection and injury to the structures involved in erectile function. Repeated stimulation of the CN, without the need for lifting and drying, was achieved by using a 125 µm bipolar silver electrode and biocompatible silicon glue to isolate the electrode-nerve complex. This method prevents neuropraxia by reducing stretching and drying the nerve and provides complete isolation of the nerve, negating electrical leakage and preventing stimulation of alternative pathways.

The effect of cavernous nerve traction on erectile function in rats

We performed this study to evaluate the effect of cavernous nerve (CN) traction on erectile function in rats. Thirty-two 8- week-old Sprague–Dawley rats were divided into four groups: control, 1-minute CN traction, 2-minute CN traction, and 2-minute CN crush. CN traction was performed using a glass hook with a tensile force of 0.2 Newton. One month later, the mean arterial pressure (MAP) and intracavernosal pressure (ICP) in response to CN stimulation were measured to assess erectile function. The penis and major pelvic ganglion (MPG) were harvested to explore the expression of neuronal nitric oxide synthase (nNOS) and neurofilament, fibrosis and apoptosis. The ICP/MAP ratio was reduced in the 2-minute CN traction group compared with the control group (P < 0.05). The ICP/MAP ratio in the CN crush group was lower than in the other three groups (P < 0.05, for each). Expression of nNOS in both MPG and dorsal penile nerve was lower in the CN traction group than in the control group, but was higher than in the CN crush group (P < 0.05). Nerve fiber number in the dorsal penile nerve was reduced by 2-minute CN traction (P < 0.05). The ratios of collagen to smooth muscle content and the apoptosis were both increased the in 2-minute CN traction group compared with the control group (P < 0.05). The findings indicate that CN traction is an effective CN injury model and the injury it caused is relatively mild compared with the CN crush model.

Neuroprotective effect of docosahexaenoic acid nanoemulsion on erectile function in a rat model of bilateral cavernous nerve injury

There is an unmet need for treatment of erectile dysfunction resulting from radical prostatectomy and cavernous nerve (CN) injury. Given the neuroprotective properties of docosahexaenoic acid (DHA), we investigated its effect on penile functional and structural recovery in a rat model of bilateral cavernous nerve injury. Rats were subject to CN injury and received intraperitoneal administration of either vehicle or a DHA nanoemulsion (nano-DHA) at 10, 50, or 250 μg/kg. Functional testing and histological analyses were performed at 28 days post-injury. The maximum intracavernosal pressure (ICP) and other measures of erectile function were significantly higher in the nano-DHA groups than in the vehicle group (p < 0.05). The ratio of area of expression of neuronal nitric oxide synthase (nNOS)/β-III tubulin, numbers of axon and smooth muscle cell content were significantly higher in the 50 μg/kg nano-DHA group than in the vehicle group (p < 0.05). A qualitative increase in the smooth muscle cells/collagen ratio and decrease in apoptosis was observed in the nano-DHA groups relative to the vehicle group: however, these differences were not statistically significant. Our data demonstrate that nano-DHA, particularly the 50 μg/kg regimen, improves erectile function after bilateral CN injury in rats by neuroprotection and other anti-fibrotic and anti-apoptotic mechanisms.

Peptide amphiphile nanofiber hydrogel delivery of sonic hedgehog protein to the cavernous nerve to promote regeneration and prevent erectile dysfunction

Erectile dysfunction (ED) has high impact on quality of life in prostatectomy, diabetic and aging patients. An underlying mechanism is cavernous nerve (CN) injury, which causes ED in up to 80% of prostatectomy patients. We examine how sonic hedgehog (SHH) treatment with innovative peptide amphiphile nanofiber hydrogels (PA), promotes CN regeneration after injury. SHH and its receptors patched (PTCH1) and smoothened (SMO) are localized in PG neurons and glia. SMO undergoes anterograde transport to signal to downstream targets. With crush injury, PG neurons degenerate and undergo apoptosis. SHH protein decreases, SMO localization changes to the neuronal cell surface, and anterograde transport stops. With SHH treatment SHH is taken up at the injury site and undergoes retrograde transport to PG neurons, allowing SMO transport to occur, and neurons remain intact. SHH treatment prevents neuronal degeneration, maintains neuronal, glial and downstream target signaling, and is significant as a regenerative therapy.

Effects of Fine Particulate Matter on Erectile Function and Its Potential Mechanism in Rats

OBJECTIVE

To investigate whether the exposure to fine particulate matter (PM_2.5) in a rat model can impair erectile function and the possible mechanism.

MATERIALS AND METHODS

Sprague-Dawley rats were distributed into 4 groups (n = 9 each): 1 control group and 3 groups exposed to different levels of PM_2.5. Rats were exposed to PM_2.5 (0.0 [saline control], 0.8, 1.6, and 3.2 mg/rat). After exposure period, the ratio of maximum intracavernosal pressure to mean arterial pressure, molecular-biological indicators in corpus cavernosum tissue and plasma, and the pathologic changes of the lung tissue and penile tissue were detected and compared between the control group and the 3 exposure groups.

RESULTS

The ratio of maximum intracavernosal pressure to mean arterial pressure in 2 groups exposed to PM_2.5 was significantly lower than that of the control group only (P <.05). Exposure to PM_2.5 could trigger the significant increase of plasma malondialdehyde, vascular endothelial growth factor, C-reactive protein, and tumor necrosis factor-α in experimental groups than that of the control group (P <.05). Expression of endothelial nitric oxide synthase (NOS), neuronal NOS, cyclic guanosine monophosphate, NOS activity, and content of reactive oxygen species in penile tissue were higher than that of the control group in a dose-response way (P <.05).

CONCLUSION

The function of penile erection is impaired by exposure to PM_2.5. The decrease in the expression of endothelial NOS and NOS activity in penile cavernous tissue caused by systemic inflammatory and oxidative stress status induced by exposure to PM_2.5 may be one of the important risk factors of erectile dysfunction.

Gene expression profile comparison in the penile tissue of diabetes and cavernous nerve injury-induced erectile dysfunction rat model

PURPOSE

To investigate the effects of cavernous nerve injury (CNI) on gene expression profiles in the cavernosal tissue of a CNI-induced erectile dysfunction (ED) model and to provide a basis for future investigations to discover potential target genes for ED treatment.

MATERIALS AND METHODS

Young adult rats were divided randomly into 2 groups: sham operation and bilateral CN resection. At 12 weeks after CNI we measured erectile responses and performed microarray experiments and gene set enrichment analysis to reveal gene signatures that were enriched in the CNI-induced ED model. Alterations in gene signatures were compared with those in the diabetes-induced ED model. The diabetic-induced ED data is taken from GSE2457.

RESULTS

The mean ratio of intracavernosal pressure/blood pressure for the CNI group (0.54±0.4 cmH2O) was significantly lower than that in the sham operation group (0.73±0.8 cmH2O, p<0.05). Supervised and unsupervised clustering analysis showed that the diabetes- and CNI-induced ED cavernous tissues had different gene expression profiles from normal cavernous tissues. We identified 46 genes that were upregulated and 77 genes that were downregulated in both the CNI- and diabetes-induced ED models.

CONCLUSIONS

Our genome-wide and computational studies provide the groundwork for understanding complex mechanisms and molecular signature changes in ED.

Erectile function after anastomotic urethroplasty for pelvic fracture urethral injuries

There is an established association between ED and pelvic fracture urethral injuries (PFUIs). However, ED can occur after the injury and/or the urethral repair. To our knowledge, only one study of erectile function (EF) after urethroplasty for PFUIs used a validated questionnaire. This study was carried out to determine the impact of anastomotic posterior urethroplasty for PFUIs on EF. We retrospectively reviewed the computerized surgical records to identify patients who underwent anastomotic urethroplasty for PFUIs from 1998 to 2014. Those patients were contacted by phone or mail and were re-evaluated in the outpatient clinic by International Index of Erectile Function questionnaire; in unmarried men, the single-question self-report of ED was used for evaluation of EF, clinical examination and penile color Doppler ultrasonography (CDU) for men with ED. Overall, 58 patients were included in the study among whom 36 (62%) men were sexually active and the remaining 22 (38%) were single. The incidence of ED among our group is 72%. All patients developed ED after initial pelvic trauma and none of our patients had impaired EF after urethroplasty. The incidence of ED increased proportionally with severity of pelvic trauma. All patients with type-C pelvic fracture, associated symphysis pubis diastasis, sacroiliac joints diastasis and bilateral pubic ramus fractures had ED. Men with PFUIs had worse EF than men in other series with pelvic fractures without urethral injury. The majority (88%) of men with ED showed veno-occlusive dysfunction on penile CDU. So we concluded that men with PFUIs had a high incidence of ED up to 72%. Anastomotic posterior urethroplasty had no negative impact on EF and the development of ED after PFUIs was related to the severity of the original pelvic trauma. Veno-occlusive dysfunction is the commonest etiology of ED on penile CDU.

Long-Term Outcomes of Using Hyaluronic Acid-Carboxymethylcellulose Adhesion Barrier Film on the Neurovascular Bundle

INTRODUCTION/OBJECTIVE

We hypothesize that the use of hyaluronic acid-carboxymethylcellulose (HACM) adhesion barrier at the neurovascular bundle may hasten the return of erectile function after robot-assisted laparoscopic prostatectomy.

MATERIALS AND METHODS

A retrospective review identified 462 consecutive patients who underwent a nerve-sparing prostatectomy between 2009 and 2012. The first 246 patients were administered the barrier film, while the next 216 patients, the control group, did not receive HACM. Postoperative erectile function and oncologic outcomes were compared. Independent t-test and Kaplan-Meier analysis were conducted, p < 0.05 was considered significant.

RESULTS

The two groups were well matched, without significant differences in age, weight, operative time, prostate size, preoperative prostate-specific antigen, sexual health inventory for men (SHIM), or AUA symptom scores. The mean SHIM was significantly higher for the experimental group at 6 months (6.39 vs 4.75, p = 0.008), 9 months (7.32 vs 5.44, p = 0.006), 1 year (8.52 vs 6.90, p = 0.049), and 18 months (10.01 vs 7.60, p = 0.018). This effect was not noted beyond 18 months. A subgroup analysis of patients with initial SHIM scores 22 or greater demonstrated a higher rate of return to the preoperative SHIM score for the barrier film group, 23% vs 12% (p = 0.046). There was no significant difference in biochemical recurrence between groups, with a median follow-up duration of 18 months.

CONCLUSIONS

HACM application at the neurovascular bundle during prostatectomy may decrease the time to return of erectile function, with improved SHIM at 6 to 18 months after surgery. This effect is more pronounced in patients with better baseline erectile function. There is no significant effect on biochemical recurrence.

Sonic hedgehog delivery from self-assembled nanofiber hydrogels reduces the fibrotic response in models of erectile dysfunction

Erectile dysfunction (ED) is a serious medical condition in which current treatments are ineffective in prostatectomy and diabetic patients, due to injury to the cavernous nerve (CN), which causes irreversible remodeling of the penis (decreased smooth muscle and increased collagen), through a largely undefined mechanism. We propose that sonic hedgehog (SHH) and neural innervation, are indispensable regulators of collagen in the penis, with decreased SHH protein being an integral component of the fibrotic response to loss of innervation. We examined collagen abundance and morphology in control (Peyronie's), prostatectomy and diabetic patients, and in rat models of penile development, CN injury, SHH inhibition and under regenerative conditions, utilizing self-assembling peptide amphiphile (PA) nanofiber hydrogels for SHH delivery. Collagen abundance increased in penis of ED patients. In rats, collagen increased with CN injury in a defined time frame independent of injury severity. An inverse relationship between SHH and collagen abundance was identified; SHH inhibition increased and SHH treatment decreased penile collagen. SHH signaling in the pelvic ganglia (PG)/CN is important to maintain CN integrity and when inhibited, downstream collagen induction occurs. Collagen increased throughout penile development and with age, which is important when considering how to treat fibrosis clinically. These studies show that SHH PA treatment reduces collagen under regenerative post-prostatectomy conditions, indicating broad application for ED prevention in prostatectomy, diabetic and aging patients and in other peripheral nerve injuries. The PA nanofiber protein vehicle may be widely applicable as an in vivo delivery tool.

STATEMENT OF SIGNIFICANCE

We use self-assembling peptide amphiphiles (PA) as biological delivery vehicles to prevent cavernous nerve (CN) injury induced erectile dysfunction (ED). These versatile hydrogels were molecularly pre-programmed for sonic hedgehog (SHH) protein delivery, either from an injectable solution with fast, in situ assembly into a soft hydrogel, or by highly aligned monodomain nanofiber bundles. We used PAs to examine a novel neuronal component to collagen regulation and the role of SHH in the fibrotic response to CN injury. SHH perturbation in the penis or the CN, selectively impacts collagen, with SHH inhibition increasing and SHH treatment suppressing collagen. These results suggest that SHH treatment by PA has translational potential to suppress collagen induction and remodelling, an irreversible component of ED development.

Nanoparticle Improved Stem Cell Therapy for Erectile Dysfunction in a Rat Model of Cavernous Nerve Injury

PURPOSE

Recently intracavernous injection of stem cells has garnered great interest as a potential treatment of erectile dysfunction. However, most stem cells are washed out immediately after intracavernous injection. The goal of this study was to investigate using NanoShuttle™ magnetic nanoparticles to maintain stem cells in the corpus cavernosum after intracavernous injection, thereby improving stem cell therapy of erectile dysfunction in an animal model.

MATERIALS AND METHODS

Adipose derived stem cells were magnetized with NanoShuttle magnetic nanoparticles to create Nano-adipose derived stem cells. A total of 24 rats underwent bilateral cavernous nerve crush and were randomly assigned to 3 groups, including adipose derived stem cells, Nano-adipose derived stem cells and Nano-adipose derived stem cells plus magnet. Cells were tracked at days 1, 3, 5 and 9 after intracavernous injection. Another 40 rats with bilateral cavernous nerve crush were randomly assigned to 4 groups, including bilateral cavernous nerve crush, bilateral cavernous nerve crush plus adipose derived stem cell intracavernous injection, bilateral cavernous nerve crush plus Nano-adipose derived stem cell intracavernous injection and bilateral cavernous nerve crush plus Nano-adipose derived stem cell intracavernous injection plus magnet. Functional testing and histological analysis were performed 4 weeks after intracavernous injection.

RESULTS

In the in vitro study 1) NanoShuttle magnetic nanoparticles were successfully bound to adipose derived stem cells and 2) Nano-adipose derived stem cells migrated toward the magnet. In the in vivo study 1) cell tracking showed that Nano-adipose derived stem cells were successfully retained in the corpus cavernosum using the magnet for up to 3 days while most adipose derived stem cells were washed out in other groups by day 1 after intracavernous injection, and 2) intracavernous pressure/mean arterial pressure, and αSMA (α-smooth muscle actin) and PECAM-1 (platelet endothelial cell adhesion molecule 1) expression in the Nano-adipose derived stem cell group was significantly higher than in the other groups.

CONCLUSIONS

Magnetization of adipose derived stem cells with NanoShuttle magnetic nanoparticles kept adipose derived stem cells in the corpus cavernosum and improved adipose derived stem cell therapy of erectile dysfunction in an animal model.

Animal models of erectile dysfunction

Erectile dysfunction (ED) is a prevalent male sexual dysfunction with profound adverse effects on the physical and the psychosocial health of men and, subsequently, on their partners. The expanded use of various types of rodent models has produced some advances in the study of ED, and neurophysiological studies using various animal models have provided important insights into human sexual dysfunction. At present, animal models play a key role in exploring and screening novel drugs designed to treat ED.

Pelvic nerve injury negatively impacts female genital blood flow and induces vaginal fibrosis-implications for human nerve-sparing radical hysterectomy

OBJECTIVE

This study sought to develop a novel animal model to study the impact of nerve-sparing radical hysterectomy (NSRH) on female genital blood flow.

DESIGN

In vivo animal study.

POPULATION

Thirty Sprague-Dawley female rats.

MATERIALS AND METHODS

Female rats underwent either unilateral pelvic nerve (PN) crush (PNC; n = 9), or crush of both the PNs and all efferent nerves in the pelvic plexus ('clock-nerve crush', CNC; n = 9). Under anaesthesia, we electrically stimulated the crushed PN at 3 and 10 days after crush while monitoring blood pressure and recording clitoral and vaginal blood flows by laser Doppler. Uninjured PNs were stimulated as an internal control. Twelve additional rats were assigned either to bilateral PNC or sham surgery, and genital tissues were processed 10 days after injury for in vitro analysis.

MAIN OUTCOME MEASURES

Genital blood flow, nNOS, eNOS, collagen I-III.

RESULTS

Stimulation of the crushed PN in both groups subjected to PNC and CNC induced significantly lower peak genital blood flow at 3 and 10 days (P < 0.05) compared to stimulation of the non-crushed control PN. The immunofluorescence and Western blot analyses revealed that all injured rats exhibited more vaginal collagen III and collagen I than rats did that ad undergone sham surgeries (P < 0.05). PCN reduced nNOS expression in both clitoral and vaginal tissue.

CONCLUSIONS

Based on our study it may be hypothesised that NSRH might cause reductions of genital blood flow and vaginal fibrosis due to neurapraxia of the pelvic nerve and reductions of nNOS nerve fibres in clitoral and distal vaginal tissue.

TWEETABLE ABSTRACT

Pelvic nerve neurapraxia during nerve-sparing radical hysterectomy could lead to sexual arousal dysfunction.

Stem cell therapy for erectile dysfunction of cavernous nerve injury rats: a systematic review and meta-analysis

INTRODUCTION

Stem cell treatment is a novel therapeutic strategy for erectile dysfunction (ED) patients with bilateral cavernous nerve injury (CNI). The relative animal studies provide important clues to design pre-clinical studies and clinical studies further in the future.

PURPOSE

This study aims to evaluate the effects and influential factors of stem cell transplantation on ED rats with CNI.

MATERIALS AND METHODS

We searched PubMed and EBSCO databases published before April 30, 2014 for pre-clinical studies to evaluate the efficacy of stem cell transplantation in the treatment of ED rats with CNI. A systematic review and a planned subgroup analysis were performed to identify whether or not some certain influential factors could bring significant effects on stem cell treatment.

RESULTS

12 studies with 319 rats were enrolled in this meta-analysis. Pooled analysis results confirmed the efficacy of stem cell transplantation. Subgroup analysis results showed that treatment effects were not related to CNI models, follow-up time, stem cell species, stem cell sources, markers and delivery approaches in the transplantation. Uncultured stem cells were poorly effective compared with cultured stem cells. Periprostatic implantation (PPI) with acellular scaffolds could promote cavernous nerve regeneration, but was less effective for smooth muscle cell recovery. Stem cells modified by NGF or BDNF combined with udenafil/bFGF seemed to be more effective than those modified by BDNF alone.

CONCLUSION

This meta-analysis shows that stem cell therapy can be performed to recover erectile function. Future studies should focus on nerve restoration and vascular cell recovery. The synergistic actions of multiple growth factors following stem cell transplantation should also be considered as beneficial strategies to obtain preferable effects.

Current status of penile rehabilitation after radical prostatectomy

Although disease-free survival remains the primary goal of prostate cancer treatment, erectile dysfunction (ED) remains a common complication that affects the quality of life. Even though several preventive and therapeutic strategies are available for ED after radical prostatectomy (RP), no specific recommendations have been made on the optimal rehabilitation or treatment strategy. Several treatment options are available, including phosphodiesterase-5 inhibitors, vacuum erection devices, intracavernosal or intraurethral prostaglandin injections, and penile prostheses. Urologists must consider more effective ways to establish optimal treatments for ED after RP. ED is an important issue among patients with prostate cancer, and many patients hope for early ED recovery after surgery. This review highlights the currently available treatment options for ED after RP and discusses the limitations of each.

[Should we recommend an erectile rehabilitation after radical prostatectomy? Systematic review of the literature by the Sexual Medicine Committee of the French Urology Association]

INTRODUCTION

Radical prostatectomy has evolved considerably during the last 20 years, with one hand, a thorough knowledge of the anatomy of the prostate, and secondly, the introduction of new conservation techniques of neurovascular bundles. Despite this progress, the rate of post-prostatectomy erectile dysfunction varies between 30 and 90% depending on the series and this element impacts the quality of life after radical prostatectomy. The objective of this work was to conduct a review of the literature in order to evaluate the various protocols of post-radical prostatectomy erectile rehabilitation.

PATIENTS AND METHODS

A systematic review of the literature from the basic PubMed search was performed using the following keywords. Therapy erectile dysfunction, radical prostatectomy, penile rehabilitation, phosphodiesterase 5 inhibitor, intracavernous injection.

RESULTS

The critical analysis of selected studies highlights the lack of standard protocol that established erectile rehabilitation early after radical prostatectomy. These studies have shown that early treatment, injections or intracavernous PDE5 inhibitors improved recovery of erections as recommended by the French Association of Urology.

CONCLUSION

Management of disorders of post-radical prostatectomy sexuality is essential, it must be organized in a well-established protocol combining pharmacological and therapeutic education assistances delivered by practitioners or nurses. It would need to develop in a clinical trial a standard protocol.