Inhibition of proNGF pathway restores erectile function by enhancing cavernous angiogenesis and neural regeneration in streptozotocin-induced diabetic mouse
Nguyen, NM1; Song, K-M1; Choi, M-J1; Ghatak, K1; Kwon, M-H1; Kang, D-H1; Yin, GN1; Ryu, J-K1; Suh, J-K1
1: Inha University, College of Medicine, Korea, South
Objective: Patients with diabetic erectile dysfunction (ED) usually respond poorly to oral PDE5 inhibitors due to a lack of bioavailable nitric oxide from severe endothelial and neural dysfunction. ProNGF and its receptor p75NTR are known to be up-regulated in diabetic condition and to induce endothelial cell apoptosis and neuronal degeneration. The aim of this study was to investigate effectiveness of anti-proNGF neutralizing antibody (proNGF-Ab) in restoring erectile function in streptozotocin-induced diabetic mouse.
Methods: Diabetes was induced by intraperitoneal injection of streptozotocin (50 mg/kg) into 8-week-old C57BL/6 male mice for 5 consecutive days. At 8 weeks after the induction of diabetes, the animals were distributed into 3 groups: controls, streptozotocin-induced diabetic mice receiving repeated intracavernous injections of PBS (days -3 and 0; 20 μL) or proNGF-Ab (days -3 and 0; 20 µg in 20 μL of saline). We measured erectile function by electrical stimulation of the cavernous nerve at 2 weeks after treatment. The penis was then harvested for histologic and biochemical studies.
Results: The cavernous expression of proNGF and p75NTR was up-regulated in diabetic mice. Local delivery of proNGF-Ab into the corpus cavernosum of diabetic mice was effective to neutralize proNGF and profoundly down-regulated expression of p75NTR. Intracavernous injection of proNGF-Ab induced significant restoration of erectile function in diabetic mice, which reach up to 90-100% of control values. ProNGF-Ab significantly increased cavernous endothelial cell content and endothelial cell-cell junction proteins; decreased endothelial cell apoptosis; and restored neuronal cell content in the cavernous tissue of diabetic mice.
Conclusion: Our findings suggest that inhibition of proNGF pathway is a promising therapeutic strategy for diabetic ED.
Work supported by industry: yes, by The Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea (Ji-Kan Ryu, HI15C0508) and The National Research Foundation of Korea(NRF) funded by the Ministry of Education (Kang-Moon Song, 2017R1A6A3A11030261) (industry funding only - investigator initiated and executed study).Go Back