Sac-1004, a Pseudo-Sugar Derivative of Cholesterol, Restores Erectile Function through Reconstruction of Nonleaky and Functional Cavernous Angiogenesis in the Streptozotocin Induced Diabetic Mouse

Purpose: We examined whether and how Sac-1004, a vascular leakage blocker, would restore erectile function in an animal model of diabetic erectile dysfunction. Materials and Methods: Eight-week-old C57BL/6J mice were used. Diabetes was induced by intraperitoneal injection of streptozotocin. Eight weeks after diabetes induction the animals were divided into 6 groups, including controls, diabetic mice that received repeat intracavernous injections of phosphate buffered saline (20 mu l) on days -3 and 0, and diabetic mice that received repeat intracavernous injections of Sac-1004 on days -3 and 0 (1, 2, 5 and 10 mu g, respectively, in 20 mu l phosphate buffered saline). One week after injection erectile function was measured by cavernous nerve stimulation. The penis was then harvested for histological examinations and Western blot analysis. Results: Local delivery of Sac-1004 in the corpus cavernosum restored erectile function in diabetic mice. The highest erectile response was noted at a dose of 5 mu g with a response comparable to that in the control group. Sac-1004 significantly increased cavernous endothelial and smooth muscle contents, and induced endothelial nitric oxide synthase phosphorylation (Ser1177). Sac-1004 decreased extravasation of oxidized low density lipoprotein by restoring endothelial cell-cell junction proteins and pericyte content. Sac-1004 also promoted tube formation in primary cultured mouse cavernous endothelial cells in vitro. Sac-1004 mediated cavernous angiogenesis and erectile function recovery was abolished by inhibiting angiopoietin-1-Tie2 signaling with soluble Tie2 antibody. Conclusions: With the effects of angiogenesis and antipermeability Sac-1004 reestablishes structural and functional cavernous sinusoids. This is highly promising for future treatment of erectile dysfunction from vascular causes.