Nonhuman primate model of persistent erectile and urinary dysfunction following radical prostatectomy: Feasibility of minimally invasive therapy

OBJECTIVE: Persistent urinary incontinence (UI) and/or erectile dysfunction (ED) occur in 30-50% of post-radical prostatectomy patients regardless of nerve sparing approaches. Identification of potential treatment options for these patients will require testing in an animal model that develops these chronic conditions. The objective was to characterize a nonhuman primate (NHP) model of persistent post-prostatectomy ED and UI and then test the feasibility of periurethral injection of the chemokine CXCL-12. METHODS: Ten adult male cynomolgus monkeys were used. Two were used for study of normal male nonhuman primate genitourinary anatomy. Five were used for measures of sexual behavior, peak intra-corporal pressure (ICP), abdominal leak point pressures (ALPP) 3 and 6-months post open radical prostatectomy (ORP). Three additional ORP animals received ultrasound-guided peri-urethral injection of chemokine CXCL12 6 weeks after ORP, and UI/ED evaluated for up to 3 months. RESULTS: The anatomy, innervation, and vascular supply to the prostate and surrounding tissues of these male NHPs are substantially similar to those of human beings. ORP resulted in complete removal of the prostate gland along with both neurovascular bundles and seminal vesicles while permitting stable restoration of vesico-urethral patency. ORP produced sustained (6 months) decreases in ALPP, ICP's, and sexual function. Transurethral injection of chemokine CXCL12 was feasible and had beneficial effects on erectile and urinary function. CONCLUSIONS: ORP in NHPs produced persistent erectile and urinary tract dysfunction. Periurethral injection of CXCL-12 was feasible and improved both urinary incontinence and erectile dysfunction and suggests that this model can be used to test new approaches for both conditions.