BACKGROUND: The intracavernosal (IC) injection of chitosan activated platelet rich plasma (cPRP) has shown to improve the erectile dysfunction in cavernous nerve injury rat model. However, the action target of PRP in improving neurogenic erectile dysfunction remains unclear. We aimed to determine the effect of cPRP action at early stage that further mediates its effect on erectile function (EF) recovery in the bilateral cavernous nerve crushing (BCNC) injury rat model.
METHODS: Fifty-four rats were randomly divided into two equal groups: intracavernosal ( IC) injection of saline after BCNC (group 1) and IC injection of cPRP after BCNC (group 2). Five animals in each group were euthanized at 3, 7 and 14 day (d) post-injection, and the tissues were harvested to conduct transmission electron microscopy and histological assays. Six animals in each group were used to determine the recovery of EF at 14 and 28 d post-injury.
RESULTS: IC injections of cPRP increased all EF parameters at 28 d and 14 d post-injury (p < 0.05). cPRP injections simultaneously prevented the loss of neuronal nitric oxide synthase-positive neurons (p < 0.05) and nerve fibers (p < 0.05) in the major pelvic ganglion and cavernous nerve (CN), respectively, compared with saline injections. This simultaneous accelerated the regeneration of myelinated axons of the CN, reduced apoptosis, and enhanced the proliferation of the corporal smooth muscle cells at an earlier stage.
CONCLUSIONS: These results suggest that the application of cPRP was beneficial to restore EF via neuroprotective and tissue-protective effects at early stage.

BACKGROUND: Neuroprotection and neuroregeneration of cavernous nerve plexus by biological/bioengineering solutions may have the potential to maintain erectile function.
OBJECTIVE: We evaluated the efficacy of a newly developed artificial nerve sheet using freeze-dried alginate (ALG) with polyglycolic acid (PGA) mesh in a rat model.
METHODS: Bilateral cavernous nerves of male rats were excised to make an approximately 2 mm gap. A piece of the sponge-like freeze-dried sheet created by covalent cross-linking of ALG gel combined with PGA mesh was placed over the gap to cover each stump without any neural anastomosis. We compared erectile functions in the ALG groups with those in the sham group and the bilateral nerve excision group (n = 12, each).
METHODS: Main outcome measure was a rat model with cavernous nerve excision.
RESULTS: All rats in the sham group had erection at 63 or 64 days, and mating behavior was confirmed in 10 rats (83.3%) of the sham group at 56 to 62 days. No erection and mating behavior was observed in the excision group. Ten of the 12 (83.3%) rats in the ALG group had a mating behavior and an erection, and the rates of erection and mating behavior were significantly higher in the ALG group than those in the excision group (P < .01, P < .01, respectively). Using a retrograde FluoroGold, the rate of FluoroGold positive pelvic ganglia proximal to the gap at 61 or 62 days was significantly higher in the ALG group than that in the excision group (P = .014).
CONCLUSIONS: The results of our animal study have demonstrated that simply filling the cavernous nerve gap using the non-tubular artificial nerve sheets made of ALG with PGA mesh restored erectile function after cavernous nerve excision. Narita S, Obara T, Ishikawa N, et al. Cavernous Branched Nerve Regeneration Using Non-Tubular Artificial Nerve Sheets Using Freeze-Dried Alginate Gel Combined With Polyglycolic Acid Mesh in a Rat Model. Sex Med 2021;9:100308.

BACKGROUND: 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.
OBJECTIVE: 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.
METHODS: 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.
CONCLUSIONS: 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.

Prostatic radiation therapy (RT) often causes erectile dysfunction (ED) and the mechanisms governing RT-induced ED are unclear with a lack of therapeutic strategies.
To determine the effects of ex vivo RT on major pelvic ganglion (MPG) neuron survival, and neurite growth in whole vs dissociated culture.
MPGs were removed and irradiated (0 or 8 Gy) from male Sprague Dawley rats. For dissociated culture, MPG neurons were digested in collagenase/dispase and cultured on coverslips. Immunofluorescent staining for beta-tubulin III (TUBB3; neuron marker), neuronal nitric oxide synthase (nNOS; nitrergic marker), tyrosine hydroxylase (TH; sympathetic marker), and terminal deoxynucleotidyl transferase dUTP nick end labeling assessed neurite length, branching, autonomic neuron density, and apoptosis. For whole organ culture, MPGs were grown in Matrigel. Gene expression of apoptotic markers (caspase 1, 3), TUBB3, nNOS, TH, and Schwann cells (Sox10, Krox20, glial fibrillary acid protein) was measured in whole organ cultured MPGs by quantitative polymerase chain reaction.
After 72 hours, neurite length, branching, autonomic neuron density, and apoptosis were assessed, and gene expression was measured.
RT increased apoptosis in dissociated neurons measured by terminal deoxynucleotidyl transferase dUTP nick end labeling (P < .001) and whole MPG culture via upregulation of caspase 3 gene expression (P < .05). Nitrergic neurons were markedly decreased in irradiated dissociated culture (P < .05), while nNOS gene expression was upregulated in irradiated whole organ culture (P < .05). The proportion of dissociated sympathetic neurons and whole organ TH gene expression remained unchanged after RT. Interestingly, RT dissociated neurites were 22% shorter than controls, while RT whole organ neurites were 15% longer than controls (P < .01). MPG Schwann cells markers (Sox10, Krox20) were elevated after RT in whole organ culture.
Prostatic RT leads to increased neuronal cell death and less erectogenic nitrergic neurons contributing to ED.
The advantages of dissociated neuron culture include distinct neurites which are easily measured for apoptosis, length/branching, and specific neuron types. In contrast, whole MPG culture is advantageous as it contains all the supporting cells present in vivo.
The 2 different culture methods demonstrated opposing neurite growth after RT indicating the importance of supporting cell network to promote pelvic neuron neuritogenesis and survival following RT. Randolph JT, Pak ES, Koontz BF, et al. Ex Vivo Radiation Leads to Opposing Neurite Growth in Whole Ganglia vs Dissociated Cultured Pelvic Neurons. J Sex Med 2020;17:1423-1433.

Potency preservation often does not meet expectation despite nerve-sparing prostatectomy.
To set the protocol for intraoperative cavernous nerve monitoring and mapping during robot-assisted radical prostatectomy (RARP), and to evaluate its safety and clinical feasibility.
A prospective phase I/II, feasibility study was performed. A total of 30 patients with prostate cancer who underwent RARP at a high-volume tertiary academic hospital were enrolled.
Pudendal somatosensory evoked potential, bulbocavernosus reflex, spontaneous corpus cavernosum electromyography (CC-EMG), median nerve stimulation evoked CC-EMG, and neurovascular bundle (NVB)-triggered CC-EMG with various stimulation protocols were assessed during conventional RARP under total intravenous anesthesia with controlled muscle relaxation.
The primary endpoint was the completion rate of planned surgery and assessment. Adverse events, and erectile and urinary functions were evaluated within 1 yr. CC-EMGs were graded and correlated with functional outcomes.
The completion rate was 100%. Only one patient experienced adverse events, which were not related to study intervention. Grades of CC-EMGs including NVB-triggered CC-EMG before prostate removal were associated with baseline five-item International Index of Erectile Function (IIEF-5) score (grades 0-1, 4.6±2.7; grade 2, 13.2±6.8; grades 3-4, 16.6±5.9; p=0.003). Furthermore, grades of CC-EMGs including NVB-triggered CC-EMG after prostate removal were significantly associated with potency recovery (grade 0, 12.5%; grade 1, 0%; grade 2, 33.3%; grades 3-4, 100% at 12 mo; p=0.005) and postoperative IIEF-5 scores at all evaluation time points (grades 0-1, 2.6±2.8; grade 2, 4.3±5.8; grades 3-4, 15.7±11.0 at 12 mo; p=0.003).
We successfully established the protocol for safe intraoperative cavernous nerve monitoring and mapping using CC-EMG during RARP. Its grades were well correlated with erectile function.
In this first-in-human feasibility study, we successfully established the protocol for safe intraoperative cavernous nerve monitoring and mapping method during robot-assisted radical prostatectomy. The results were significantly associated with erectile function. Evaluation of clinical efficacy to preserve potency seems worthy of further optimization and investigation in confirmatory clinical trials.

Although the remaining nerve tissue can regenerate and partly restore erectile function when the cavernous nerve is compressed/severed and function lost, the limited regenerative ability of these nerve tissues often fails to meet clinical needs. Adipose-derived stem cells are easy to obtain and culture, and can differentiate into neural cells. Their proliferation rate is easy to control and they may be used to help restore injured cavernous nerve function. Sprague-Dawley male rats (n = 45) were equally randomized into three groups: fifteen rats as a sham-operated group, fifteen rats as a bilateral nerve crush (BINC) group (with no further intervention), fifteen rats as a BINC with intracavernous injection of one million neural-like cells from adipose-derived stem cells (NAS) (BINC + NAS) group. After 4 weeks, erectile function was assessed by stimulating the cavernous body. The number of myelinated axons in the dorsal cavernous nerve was determined by toluidine blue staining. The area of neuronal nitric oxide synthase-positive fibers in the dorsal penile nerve was measured by immunohistochemical staining. Masson staining was used to analyze the ratio of smooth muscle to collagen in penile tissue. The results demonstrate that maximal intracavernous pressure, the ratio of maximal intracavernous pressure to mean arterial pressure, the numbers of myelinated axons and neuronal nitric oxide synthase-positive fibers in the dorsal penile nerve, and the ratio of smooth muscle to collagen could be increased after cell transplantation. These findings indicate that neural-like cells from adipose-derived stem cells can effectively alleviate cavernous nerve injury and improve erectile function. All animal experiments were approved by the Animal Ethics Committee of Huazhong University of Science and Technology, China (approval No. 2017-1925) on September 15, 2017.

The aims of the present study were to describe, in male rats, the anatomical organization of the major and accessory pelvic ganglia (MPG, AG; respectively), the interrelationship of the pelvic plexus components, and the morphometry of the pelvic postganglionic neurons. Anatomical, histochemical and histological studies were performed in anesthetized adult Wistar male rats. We found that the pelvic plexus consists of intricate neural circuits composed of two MPG, and three pairs of AG (AGI, AGII, AGIII) anatomically interrelated through ipsilateral and contralateral commissural nerves. Around 30 nerves emerge from each MPG and 17 from AGI and AGII. The MPG efferent nerves spread out preganglionic information to several pelvic organs controlling urinary, bowel, reproductive and sexual functions, while AG innervation is more regional, and it is confined to reproductive organs located in the rostral region of the urogenital tract. Both MPG and AG contain nerve fascicles, blood vessels, small intensely fluorescent cells, satellite cells and oval neuronal somata with one to three nucleoli. The soma area of AG neurons is larger than those of MPG neurons (p < 0.005). The MPG contains about 75% of the total pelvic postganglionic neurons. Our findings corroborated previous reports about MPG inputs, and add new information regarding pelvic ganglia efferent branches, AG neurons (number and morphometry), and neural interrelationship between the pelvic plexus components. This information will be useful in designing future studies about the role of pelvic innervation in the physiology and pathophysiology of pelvic functions.

BACKGROUND: Erectile dysfunction (ED) is common following radiation therapy (RT) for prostate cancer. Although the cause of RT-induced ED is unknown, damage to both the neuronal and vascular components supporting erections are often implicated.
OBJECTIVE: To determine the effects of prostatic RT on erections, penile vascular physiology, and major pelvic ganglia (MPG) neuron growth and survival in a rat model.
METHODS: Male rats underwent 0 Gy or 22 Gy single fraction of prostate-confined, conformal RT. At 2 weeks or 10 weeks post-RT (n = 10/group), cavernous nerve stimulation was performed and erections were assessed. Tissue bath experiments were performed to assess both penile artery and internal pudendal artery (IPA) function. MPGs were dissociated and neurons grown in culture for 72 hours. Immunofluorescence staining was done to quantify neuron survival (terminal deoxynucleotidyl transferase nick-end labeling), outgrowth (beta-tubulin III), type (nitric oxide synthase [nNOS] and tyrosine hydroxylase [TH]), and nerve injury markers (small GTPase Rac1 and ninjurin-1 [Ninj-1]). Whole MPG real-time quantitative polymerase chain reaction (qPCR) was performed to measure expression of genes related to nerve type, neuron injury, repair, and myelination, such as Ninj-1, Rac1, ATF3, GAP43, GFAP, SOX10, and KROX20.
RESULTS: Intracavernosal pressure (ICP) to mean arterial pressure (MAP) ratio, smooth muscle contractility and relaxation, gene expression, neuritogenesis, and apoptosis.
RESULTS: Following RT, ICP/MAP was unchanged at 2 weeks or 10 weeks. Nerve-mediated penile contraction was increased at 2 weeks, whereas adrenergic contraction was reduced at 10 weeks. Penile relaxation and IPA vasoreactivity were unchanged. Neuronal apoptosis was more than doubled both early and late post-RT. RT caused a progressive decrease in neurite branching but an early increase and then late decrease in neurite lengthening. RT reduced the numbers of nNOS-positive neurons both early and late and also decreased MPG nitrergic gene expression. TH neurons and gene expression were unchanged at 2 weeks; however, both were decreased after 10 weeks. Although most markers of gene injury and repair were unaffected early post-RT, MPG expression of Ninj1 and GFAP increased. After 10 weeks, Ninj1 and GFAP remained elevated while markers of neuron injury (ATF3), outgrowth (GAP43 and Rac1), and myelin regulation (SOX10) were decreased.
UNASSIGNED: RT-induced ED may result from damage to the ganglia controlling erections.
UNASSIGNED: This study used a clinically relevant, prostate-confined model to examine neurovascular structures not accessible in human studies. Unfortunately, rats did not exhibit ED at this time point.
CONCLUSIONS: This is the first study to demonstrate impaired health and regeneration potential of dissociated MPG neurons following RT. Neuronal injury was apparent early post-RT and persisted or increased over time but was insufficient to cause ED at the time points examined. Powers SA, Odom MR, Pak ES, et al. Prostate-Confined Radiation Decreased Pelvic Ganglia Neuronal Survival and Outgrowth. J Sex Med 2019;16:27-41.

Erectile dysfunction after nerve injury is a common disease after radical prostatectomy. Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family, which plays an important role in the survival of existing neurons, the differentiation of new neurons, and synaptic plasticity. It has been demonstrated that low-intensity pulsed ultrasound (LIPUS) accelerates bone healing and axonal regeneration after injury. LIPUS may also be able to stimulate neuronal activity and enhance the levels of neurotrophic factors. Evidence suggests that elevated levels of BDNF in the brain have protective effects against neurodegenerative diseases. Previous studies have shown that the treatment on cavernous nerve injury repair, and protective effect plus neuro-regeneration effect by low-intensity pulsed ultrasound. They shared the similar mechanism including several trophic factors stimulation, Pl3K/akt pathway activation, and anti-fibrosis mechanism. We hypothesized that due to its combined neuroregenerative and protective effects, the non-invasive and easy-to-use method of LIPUS stimulation could have a therapeutic effect on erectile dysfunction stemming from cavernous nerve injury.

UNASSIGNED: Since Walsh first emphasized the importance of preserving the neurovascular bundle n to protect the cavernous nerve during pelvic surgery, patients\' sexual life quality has dramatically improved. Today, nerve-sparing radical prostatectomy is the established gold standard for organ-confined prostate cancer patients. Recent technical advances in functional assessment such as intraoperative electrical stimulation have unveiled new anatomical features and physiological roles. Basic research has advanced understanding of cavernous nerve function, while molecular biology has uncovered the crucial role of neuronal nitric oxide in mediating erection, and has led to new treatments such as phosphodiesterase type-5 inhibitors. A recent focus in cavernous nerve research concerns the nerve distribution external to the neurovascular bundle. The cavernous nerves in humans appear to be distributed more widely beneath the lateral pelvic fascia than in other animals, and electrical stimulation studies suggest possible involvement of these nerves in erection. These findings have prompted new surgical techniques such as the \"veil of Aphrodite\", or \"intrafascial nerve-sparing\" procedures.
UNASSIGNED: These recent anatomical and physiological studies in humans and animals and their impact are reviewed in this article.
UNASSIGNED: Further investigation should stimulate future advances in strategies to preserve erectile function in RP patients.