Volume 54, Issue 5, Pages 1179-1187 (November 2008) GDNF-Transduced Schwann Cell Grafts Enhance Regeneration of Erectile Nerves  Florian May, Kaspar Matiasek, Maurice Vroemen, Christiane Caspers, Thomas Mrva, Christian Arndt, Boris Schlenker, Peter Gais, Thomas Brill, Alexander Buchner, Armin Blesch, Rudolf Hartung, Christian Stief, Bernd Gansbacher, Norbert Weidner  European Urology  Volume 54, Issue 5, Pages 1179-1187 (November 2008) DOI: 10.1016/j.eururo.2008.02.003 Copyright © 2008 European Association of Urology Terms and Conditions

Fig. 1 (A–C) In vivo overexpression of GDNF by GDNF-transduced Schwann cells. (A) GDNF-overexpressing Schwann cells (arrowheads) could be detected in the Schwann cell–coated peripheral nerve conduits at 12 wk post-transplantation by immunohistochemistry, indicating that stable GDNF expression could be achieved in vivo. (B) In the peripheral nerve conduits that were coated with GFP-transduced Schwann cells, no GDNF expression could be detected. (C) Cerebellar purkunje cells functioned as positive controls (arrowheads) for the immunohistochemical GDNF detection method [15]. Bright-field micrographs; scale bar: 50μm. GDNF, glial cell line–derived neurotrophic factor; GFP, green fluorescent protein. European Urology 2008 54, 1179-1187DOI: (10.1016/j.eururo.2008.02.003) Copyright © 2008 European Association of Urology Terms and Conditions

Fig. 2 (A,B) Recovery of erectile function after bilateral nerve ablation and reconstruction. At either 6 or 12 wk, rats were re-operated and erectile function was evaluated. Upon direct electrical nerve stimulation, erectile response was analyzed and counted (A), and quantified by measurement of intracavernous pressure (ICP) increase divided by arterial blood pressure (RR) (B). Values represent mean±standard error of the mean. GDNF, glial cell line–derived neurotrophic factor; GFP, green fluorescent protein. European Urology 2008 54, 1179-1187DOI: (10.1016/j.eururo.2008.02.003) Copyright © 2008 European Association of Urology Terms and Conditions

Fig. 3 GDNF-transduced Schwann cell graft 12 wk after interposition within the silicone tube (transverse semithin section, light microscopy). In all specimens, regenerated nerves were usually confined to the center of the conduit surrounded by acellular matrix filling the gap between the regenerated nerve and the inner wall of the silicone tube. European Urology 2008 54, 1179-1187DOI: (10.1016/j.eururo.2008.02.003) Copyright © 2008 European Association of Urology Terms and Conditions

Fig. 4 (A,B) Comparison of GDNF-hypersecreting Schwann cell graft (A) versus GFP-transduced Schwann cell graft (B) 12 wk after interposition grafting. Left side: assembled photographs from electron micrographs (original magnification: ×3400) forming a mosaic picture. Right side: morphometric mask showing different nerve compartments after image segmentation and interactive outlining. Gray area: perineurium; red area: perineurial and endoneurial blood vessels; green area: endoneurial fibrous tissue; blue area: neural area containing myelinated and unmyelinated fibers. GDNF, glial cell line–derived neurotrophic factor; GFP, green fluorescent protein. European Urology 2008 54, 1179-1187DOI: (10.1016/j.eururo.2008.02.003) Copyright © 2008 European Association of Urology Terms and Conditions

Fig. 5 (A,B) Total cross-sectional area (A) and neural area (B) measured at the guidance channel midpoint 12 wk after interposition grafting (box-and-whisker plots). GDNF-transduced Schwann cell grafts led to larger regenerates and improved regeneration of neural tissue compared with GFP-transduced controls. GDNF, glial cell line–derived neurotrophic factor; GFP, green fluorescent protein. European Urology 2008 54, 1179-1187DOI: (10.1016/j.eururo.2008.02.003) Copyright © 2008 European Association of Urology Terms and Conditions

Fig. 6 (A,B) Ultrastructural analysis using electron microscopy revealed that axon regeneration into and through Schwann cell–filled silicone tubes improves dramatically between 6 and 12 wk postoperatively. At 6 wk, numerous myelinated and unmyelinated axon profiles were found (A); however, myelinated fibers present with a larger scatter in diameter than on postoperative week 12 (B) (see box-whisker-plots of fiber area). On week 12, axon diameter values become narrower, indicating maturation of regenerated nerves. European Urology 2008 54, 1179-1187DOI: (10.1016/j.eururo.2008.02.003) Copyright © 2008 European Association of Urology Terms and Conditions