Novel therapeutic approach for neurogenic erectile dysfunction: effect of neurotrophic tyrosine kinase receptor type 1 monoclonal antibody.

Erectile dysfunction (ED) is a major health issue in aged populations, and neurogenic ED is particularly difficult to treat. Novel therapeutic approaches are needed for treatment of neurogenic ED of peripheral origin.
To investigate the therapeutic effects of a neurotrophic tyrosine kinase receptor type 1 monoclonal antibody (TrkA-mAb) on erectile function and sexual behavior in a rat model of cavernous nerve injury (CNI).
In one experiment, 84 male rats were randomly assigned to seven groups. The groups underwent either CNI or sham surgery, subsequent injection into the major pelvic ganglion (IMPG) of phosphate-buffered saline (PBS), an immunoglobulin G (IgG) control, or TrkA-mAb, and then intracavernosal (IC) injection of either PBS or varying TrkA-mAb concentrations immediately after surgery and then 1 wk later. Erectile function was assessed and histologic/molecular analyses were performed at 6 wk after surgery. In a second experiment, 36 male rats were randomly divided into three groups. The groups underwent CNI or sham surgery and then IC injection of PBS, IgG, or TrkA-mAb immediately after surgery and for 5 wk thereafter. At 6 wk after surgery, the performance of the rats in sexual behavior tests was videotaped.
CNI or sham surgery; IMPG of PBS, IgG, or TrkA-mAb; IC injection of PBS or TrkA-mAb.
The intracavernous pressure response to cavernous nerve electrostimulation was measured and midpenile cross-sections were histologically examined. Western blotting (WB) of cavernous tissue protein was performed. Rats were assessed for chasing, mounting, intromission, and ejaculation behaviors during sexual behavior tests. The data were analyzed using one-way analysis of variance followed by the Tukey-Kramer t test.
Recovery of erectile function of varying degrees was observed in the TrkA-mAb groups. TrkA-mAb treatment significantly suppressed tyrosine hydroxylase-positive nerve fibers in the corpus cavernosum and enhanced neuronal nitric oxide synthase-positive fibers in the dorsal nerve. The ratio of smooth muscle to collagen in the corpus cavernosum was significantly improved in TrkA-mAb treatment groups compared to PBS vehicle and IgG control groups. WB confirmed these biological changes. There was a nonsignificant increase in the average number of intromissions and ejaculations in the TrkA-mAb group. The study limitations include small sample size, variability in sexual behavior, lack of data on the neuromuscular mechanism involved, and lack of information of the role of neurotrophins or cytokines in regeneration.
TrkA-mAb successfully inhibits sympathetic nerve regeneration, leads to parasympathetic nerve regeneration, and has therapeutic effects on ED and sexual behavior disorder in a rat model of CNI.
This report provides strong evidence that a neurotrophic tyrosine kinase receptor type 1 monoclonal antibody (TrkA-mAb) inhibits sympathetic nerve regeneration, leads to parasympathetic nerve regeneration, and has therapeutic effects on erectile dysfunction and sexual behavior disorder in a rat model of cavernous nerve injury. The results raise the possibility that human patients with neurogenic erectile dysfunction may respond to TrkA-mAb in a manner that parallels the response seen in our rodent study.
AuthorsGuiting Lin, Huixi Li, Xiaoyu Zhang, Jianwen Wang, Uwais Zaid, Melissa T Sanford, Victor Tu, Alex Wu, Lin Wang, Fei Tian, Helen Kotanides, Venkatesh Krishnan, Guifang Wang, Hongxiu Ning, Lia Banie, Ching-Shwun Lin, Gary G Deng, Tom F Lue
JournalEuropean urology (Eur Urol) Vol. 67 Issue 4 Pg. 716-26 (Apr 2015) ISSN: 1873-7560 [Electronic] Switzerland
PMID25847857 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
CopyrightCopyright © 2014 European Association of Urology. Published by Elsevier B.V. All rights reserved.
Chemical References
  • Antibodies, Monoclonal
  • Receptor, trkA
  • Animals
  • Antibodies, Monoclonal (administration & dosage, pharmacology)
  • Disease Models, Animal
  • Erectile Dysfunction (drug therapy, physiopathology)
  • Humans
  • Male
  • Nerve Regeneration (drug effects)
  • Penile Erection (drug effects)
  • Rats
  • Rats, Sprague-Dawley
  • Receptor, trkA (immunology)
  • Sexual Behavior, Animal (drug effects)
  • Treatment Outcome

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research network!

Choose Username:
Verify Password: