(185) MORPHOLOGICAL ANALYSIS OF TRANSGENDER TUNICA ALBUGINEA

Abstract Introduction The tunica albuginea plays a critical role in the biomechanics and physiology of the penis, as the main bearer of mechanical forces, especially during erection. Collagen fibers represent a key element of the tunica albuginea strength, however the collagen composition of the tunica remains poorly understood despite its critical role in disease development (erectile dysfunction and Peyronie's). Objective In this study, analysis of tunica morphology was performed on tissue from transgender patients, in order to identify the types of collagen/collagen composition of the tunica. Methods Transgender tunica tissue (n = 18) was obtained from patients undergoing penectomy surgery for gender reassignment. Immunohistochemical (IHC) analysis for collagen 1-2, -3 and -4, and trichrome stain were performed to characterize the collagen subtypes and abundance. Primary cell cultures were established from transgender tunica and cultures were characterized with IHC analysis for P4HB (fibroblast), alpha-ACTIN (smooth muscle), CD31 (endothelium) and nNOS (neurons). Tunica cell growth was quantified in response to Sonic hedgehog (SHH) pathway signaling. Results Trichrome stain identified the undulating structure of the tunica, which predominantly contained collagen fibers, and rare smooth muscle cells, in contrast to the corpora cavernosa which contained abundant collagen and smooth muscle. IHC analysis identified collagen 1, 2 and 4 in the tunica, but collagen 3 was not observed. Conclusions Characterization of tunica morphology in healthy patients is important to understand the mechanophysiology of the tunica. This morphological analysis identified the collagen subtypes present in patient tunica tissue and is a first step in understanding how diseases of the tunica develop. Comprehension of how collagen remodeling occurs would be useful for development of novel treatments for Peyronie’s disease. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Uronext LLC.