Recovery of erectile function after unilateral and bilateral cavernous nerve interposition grafting during radical pelvic surgery

Curcumin slow-release membrane promotes erectile function and penile rehabilitation in a rat model of cavernous nerve injury

Male erectile dysfunction (ED) caused by cavernous nerve injury is a common complication of pelvic surgery, radiotherapy, transurethral surgery or other operations. However, clinical treatment for iatrogenic or traumatic male ED is difficult and not satisfactory. Many studies have shown that curcumin can promote the repair and regeneration of peripheral nerves; however, whether curcumin can rescue cavernous nerve injury is unknown, and the poor bioavailability of curcumin limits its application in vivo. Hence, the study was conducted. A curved slow-release membrane was produced, and the properties were examined. In addition, the effects of the curcumin slow-release membrane on cavernous nerve-injured SD rats were studied. We found that polylactic acid-glycolic acid-polyethylene glycol (PLGA-PEG) can be used as a good carrier material for curcumin, and curcumin-loaded PLGA-PEG membranes can effectively rescue the cavernous nerve in SD rats, restore the continuity of the cavernous nerve, and increase the expression of nNOS mRNA and proteins in penile tissue, which can improve the penile erectile function of injured SD rats, reduce the degree of penile tissue fibrosis, and effectively promote penis rehabilitation. The curcumin slow-release membrane is proposed to be a new therapeutic approach for penile rehabilitation of cavernous nerve injury.

Surgical Techniques for Managing Post-prostatectomy Erectile Dysfunction

Purpose of Review

Due to the increasing numbers of radical prostatectomies (RP) performed for prostate cancer, a substantial number of patients are now suffering from post-operative erectile dysfunction (ED). The aim of this study is to summarize the current literature on surgical techniques for managing post-prostatectomy erectile dysfunction.

Recent Findings

The PubMed database was searched for English-language articles published up to Jan 2017 using the following search terms: “prostatectomy AND erectile dysfunction”, “prostatectomy AND penile prostheses”, and “prostatectomy AND penile implants”. All of the studies that evaluated medical treatment were excluded. In the last few decades, the understanding of the anatomy of the male pelvis and prostate has improved. This has led to significant changes in the nerve-sparing radical prostatectomy techniques, with the aim of preserving post-surgical erectile function (EF). In this scenario, the prostate vascular supply and the anatomy of the neurovascular bundles have a central role. Penile prosthesis implantation is considered the third-line treatment option for RP ED patients, and they have been reported to be a very successful treatment with the highest patient satisfaction rate.

Summary

Considering the failure of penile rehabilitation, and the lack of evidence for accessory pudendal artery (APA) preservation and nerve graft, nerve-sparing surgery and penile prostheses represent, today, the only methods to permanently and definitively preserve or erectile function after RP.

Interpositional Nerve Grafting of the Prostatic Plexus after Radical Prostatectomy

Background:

Injury to the prostatic plexus may occur during radical prostatectomy even with the use of minimally invasive techniques. Reconstruction of these nerves by interpositional nerve grafting can be performed to reduce morbidity. Although the feasibility of nerve reconstruction has been shown, long-term functional outcomes are mixed, and the role of nerve grafting in these patients remains unclear.

Methods:

A retrospective study was performed on 38 consecutive patients who underwent immediate unilateral or bilateral nerve reconstruction after open prostatectomy. Additionally, 53 control patients who underwent unilateral, bilateral, or non–nerve-sparing open prostatectomy without nerve grafting were reviewed. Outcomes included rates of urinary continence, erections sufficient for sexual intercourse, and ability to have spontaneous erections. Analysis was performed by stratifying patients by D’Amico score and laterality of nerve involvement.

Results:

Unilateral nerve grafting conferred no significant benefit compared with unilateral nerve-sparing prostatectomy. Bilateral nerve-sparing patients demonstrated superior functional outcomes compared with bilateral non–nerve-sparing patients, whereas bilateral nerve-grafting patients displayed a trend toward functional improvement. With increasing D’Amico score, there was a trend toward worsening urinary continence and erectile function regardless of nerve-grafting status.

Conclusions:

In the era of robotic prostatectomy, interpositional nerve reconstruction is not a routine practice. However, the substantial morbidity experienced in patients with bilateral nerve resections remains unacceptable, and therefore, nerve grafting may still improve functional outcomes in these patients. Further investigation is needed to improve the potential of bilateral nerve grafting after non–nerve-sparing prostatectomy.

Rat cavernous nerve reconstruction with CD133+ cells derived from human bone marrow

INTRODUCTION

Erectile dysfunction remains a major complication after surgery of pelvic organs, especially after radical prostatectomy.

AIM

The aim of this study was to assess the effect of endothelial progenitor cells on the regeneration of cavernous nerves in a rat injury model.

METHODS

A 2 mm length of the right and left cavernous nerves of 8-week-old male nude rats were excised. Alginate gel sponge sheets supplemented with 1 × 10(4) CD133+ cells derived from human bone marrow were then placed over the gaps on both sides (CD group). The same experiments were performed on sham-operated rats (SH group), rats with only the nerve excision (EX group), and rats with alginate gel sheets placed on the injured nerves (AL group).

MAIN OUTCOME MEASURES

Immunofluorescence staining and molecular evaluation were performed 4 days later. Functional and histological evaluations were performed 12 weeks later.

RESULTS

The intracavernous pressure elicited by electrical stimulation and the neuronal nitric oxide synthase-positive area in surrounding tissues of the prostate was significantly greater in the CD group. Immunofluorescence microscopy showed that CD133+ cells were assimilated as vascular endothelial cells, and the real-time polymerase chain reaction showed upregulation of nerve growth factor and vascular endothelial growth factor in the alginate gel sponge sheets of the CD group.

CONCLUSIONS

Transplantation of CD133+ cells accelerated the functional and histological recovery in this cavernous nerve injury model, and the recovery mechanism is thought to be angiogenesis and upregulation of growth factors. CD133+ cells could be an optional treatment for cavernous nerve injury after prostatectomy in clinical settings.

Cavernous nerve repair with allogenic adipose matrix and autologous adipose-derived stem cells

OBJECTIVES

To investigate whether adipose-derived matrix seeded with adipose-derived stem cells (ADSC) can facilitate the repair of injured cavernous nerves (CNs).

METHODS

Human and rat adipose tissues were decellularized and fabricated into various forms, including adipose tissue-derived acellular matrix thread (ADMT). ADMT seeded with ADSC were transplanted into subcutaneous space and examined for signs of inflammation. ADSC-seeded ADMTs were then used to repair CN injury in rats, followed by assessment of histology and erectile function.

RESULTS

Adipose tissue can be fabricated into acellular matrices of various shapes and sizes, including threads and sheets. Seeding of ADMT occurred rapidly: within 24 hours, 55% of the surface was covered with ADSC and within 1 week, 90% was covered. Transplantation of the seeded ADMT into the subcutaneous space of an allogenic host showed no signs of inflammatory reaction. At 3 months after grafting into CN injury rats, approximately twice as many cells were found on seeded ADMT as on unseeded ADMT. The seeded ADMT also had various degrees of S100 and neuronal nitric oxide synthase expression, suggesting CN axonal ingrowth. Rats grafted with seeded ADMT overall had the best erectile function recovery when compared with those grafted with unseeded ADMT and those ungrafted. However, as a result of large variations, the differences did not reach statistic significance (P = .07).

CONCLUSIONS

Grafting of ADSC-seeded matrix resulted in a substantial recovery of erectile function and improvement of histology. However, further refinement of the matrix architecture is needed to improve the success rate.