Intracavernous delivery of freshly isolated stromal vascular fraction rescues erectile function by enhancing endothelial regeneration in the streptozotocin-induced diabetic mouse.

ABSTRACT

INTRODUCTION: Men with diabetic erectile dysfunction (ED) often have severe endothelial dysfunction and respond poorly to oral phosphodiesterase-5 inhibitors. AIM: To examine whether and how freshly isolated stromal vascular fraction (SVF) promotes cavernous endothelial regeneration and restores erectile function in diabetic animals. METHODS: Eight-week-old C57BL/6J mice were used. Diabetes was induced by intraperitoneal injection of streptozotocin. SVF was isolated from epididymal adipose tissues of green fluorescence protein transgenic mice. At 8 weeks after the induction of diabetes, the animals were divided into six groups controls, diabetic mice, and diabetic mice treated with a single intracavernous injection of phosphate-buffered saline (PBS) or SVF (1 × 10(4) cells, 1 × 10(5) cells, or 2 × 10(5) cells/20 µL, respectively). MAIN OUTCOME MEASURES: Two weeks later, erectile function was measured by cavernous nerve stimulation. The penis was stained with antibodies to CD31, CD34, phosphohistone H3, phospho-endothelial nitric oxide synthase (eNOS), and vascular endothelial growth factor-A (VEGF-A). We also performed Western blot for phospho-eNOS and eNOS, and determined cyclic guanosine monophosphate (cGMP) concentration in the corpus cavernosum tissue. RESULTS: Significant improvement in erectile function was noted in diabetic mice treated with SVF at concentrations of 1 × 10(5) and 2 × 10(5) cells, which reached up to 82% of the control values. Local delivery of SVF significantly increased cavernous endothelial cell proliferation, eNOS phosphorylation, and cGMP expression compared with that in the untreated group and the PBS-treated diabetic group. Intracavernous injection of SVF increased cavernous VEGF-A expression and induced recruitment of CD34(+)CD31(-) progenitor cells. Some SVF underwent differentiation into cavernous endothelial cells. SVF-induced promotion of cavernous angiogenesis and erectile function was abolished in the presence of VEGF-Trap, a soluble VEGF-A neutralizing antibody. CONCLUSION: The results support the concept of cavernous endothelial regeneration by use of SVF as a curative therapy for diabetic ED.