Introduction It has been suggested that transforming growth factor-β1 (TGF-β1) plays an important role in the pathogenesis of diabetes-induced erectile dysfunction. Aim To investigate the expression and activity of Smad transcriptional factors, the key molecules for the initiation of TGF-β-mediated fibrosis, in the penis of streptozotocin (STZ)-induced diabetic rats. Methods Fifty-two 8-week-old Sprague–Dawley rats were used and divided into control and diabetic groups. Diabetes was induced by an intravenous injection of STZ. Main Outcome Measures Eight weeks later, erectile function was measured by electrical stimulation of the cavernous nerve (N = 12 per group). The penis was harvested and stained with Masson trichrome or antibody to TGF-β1, phospho-Smad2 (P-Smad2), smooth muscle α-actin, and factor VIII (N = 12 per group). Penis specimens from a separate group of animals were used for TGF-β1 enzyme-linked immunosorbent assay (ELISA), P-Smad2/Smad2, phospho-Smad3 (P-Smad3)/Smad3, fibronectin, collagen I, and collagen IV western blot, or hydroxyproline determination. Results Erectile function was significantly reduced in diabetic rats compared with that in controls. The expression of TGF-β1, P-Smad2, and P-Smad3 protein evaluated by ELISA or western blot was higher in diabetic rats than in controls. Compared with that in control rats, P-Smad2 expression was higher mainly in smooth muscle cells and fibroblasts of diabetic rats, whereas no significant differences were noted in endothelial cells or in the dorsal nerve bundle. Cavernous smooth muscle and endothelial cell contents were lower in diabetic rats than in controls. Cavernous fibronectin, collagen IV, and hydroxyproline content was significantly higher in diabetic rats than in controls. Conclusion Upregulation of TGF-β1 and activation of the Smad signaling pathway in the penis of diabetic rats might play important roles in diabetes-induced structural changes and deterioration of erectile function.

Introduction With the advent of genetically engineered mice, it seems important to develop a mouse model of cavernous nerve injury (CNI). Aim To establish a mouse model of CNI induced either by nerve crushing or by neurectomy and to evaluate time-dependent derangements in penile hemodynamics in vivo and subsequent histologic alterations in the cavernous tissue. Methods Twelve-week-old C57BL/6J mice were divided into 4 groups (N=36 per group): control, sham operation, bilateral cavernous nerve crush, and bilateral cavernous neurectomy group. Main Outcome Measures Three days and 1, 2, 4, 8, and 12 weeks after CNI, erectile function was measured by electrical stimulation of the cavernous nerve. The penis was then harvested and TUNEL was performed. Immunohistochemical analysis was performed assaying for caspase-3, transforming growth factor-β1 (TGF-β1), phospho-Smad2, PECAM-1, factor VIII, and smooth muscle α-actin. The numbers of apoptotic cells and phospho-Smad2-immunopositive cells in endothelial cells or smooth muscle cells were counted. Results Erectile function was significantly less in the cavernous nerve crushing and neurectomy groups than in the control or sham group. This difference was observed at the earliest time point assayed (day 3) and persisted up to 4 weeks after nerve crushing and to 12 weeks after neurectomy. The apoptotic index peaked at 1 or 2 weeks after CNI and decreased thereafter. Cavernous TGF-β1 and phospho-Smad expression was also increased after CNI. The numbers of apoptotic cells and phospho-Smad2-immunopositive cells in cavernous endothelial cells and smooth muscle cells were significantly greater in the cavernous nerve crush and cavernous neurectomy groups than in the control or sham group. Conclusion The mouse is a useful model for studying pathophysiologic mechanisms involved in erectile dysfunction after CNI. Early intervention to prevent apoptosis in smooth muscle cells and endothelial cells or to inhibit cavernous tissue fibrosis is required to restore erectile function.

Highlights d H 2 O 2 generation is mediated by interaction of Nox4 with p22 phox -SH3YL1 d SH3YL1-Nox4 regulates pro-inflammatory cytokine production and tubular damage d SH3YL1-Nox4 complex plays an important role in LPSinduced acute kidney injury

It has been hypothesized that transforming growth factor-beta1 (TGF-beta1) signalling is involved in erectile dysfunction (ED). This study was undertaken to elucidate in detail whether expression of TGF-beta1 and its type II receptor is clinically related to various causes of ED. Fifty-four patients with ED and 24 potent men were the subjects of this study. After multidisciplinary work-up, the ED was classified as psychogenic (n = 6), neurogenic (n = 15), or vasculogenic (n = 33). In every subject, percutaneous cavernous biopsy was performed using a Biopty gun. Masson's trichrome staining was used to quantitate collagen fibres and immunohistochemical staining to evaluate both TGF-beta1 and its type II receptor by scoring the intensity of immunoreactivity (score 0-6). Collagen fibres were significantly more abundant in men with vasculogenic ED (72.7 +/- 17.7%) than in control subjects (43.3 +/- 11.2%) or those with psychogenic (45.0 +/- 12.2%) or neurogenic (51.3 +/- 20.3%) ED (p < 0.01). Expression of TGF-beta1 was significantly greater in vasculogenic ED (4.3 +/- 1.3) than in the control subjects (2.4 +/- 0.9) or psychogenic ED (2.0 +/- 0.6) groups (p < 0.01). Type II receptor expression was also significantly increased in vasculogenic ED (3.9 +/- 1.3) compared with control (2.2 +/- 0.7) and psychogenic (2.2 +/- 0.8) or neurogenic (2.6 +/- 1.3) ED (p < 0.01). Of the ED groups, both the hyperlipidaemia and the atherosclerosis patients showed significantly more fibrosis than those without the condition (p < 0.05). The abundance of collagen fibres correlated well with both TGF-beta1 expression (gamma = 0.81; p < 0.001) and receptor II expression (gamma = 0.83; p < 0.001). These results suggest that TGF-beta1 and its receptor II pathway are involved in cavernous fibrosis and ED in man. Patients with vascular risk factors such as hyperlipidaemia and atherosclerosis are liable to ED by activation of this pathway.

Downregulation of the expression of the angiogenic factors and their downstream signal molecules, and decreased endothelial content in the corpus cavernosum of hypercholesterolemic rats might play important roles in the deterioration of erectile function.