INVESTIGATIVE UROLOGY

Oestrogen receptors and their relation to neural receptive tissue of the labia minora
Martin-Alguacil N, Pfaff DW, Kow LM, Schober JM
Department of Neurobiology and Behaviour, The Rockefeller University, New York, NY, USA
BJU Int. 2008; 101: 1401-6

• Objective: To assess the cellular distributions of oestrogen receptors alpha and beta (ER alpha and ER beta) and neuronal nitric oxide synthase (nNOS) in the labia minora, as knowledge about ER type and function may clarify the role of oestrogens in vaginal scar formation and improve outcomes in female genital surgery.
• Subjects and Methods: Labial samples were taken from 10 girls (aged 2-9 years) who underwent surgery for labial fusion. The waste tissue strips obtained were used for immunohistochemical identification of ER alpha and ER beta, and nNOS in the labia minora.
• Results: There was ER alpha nuclear staining in the stroma of the labia minora close to the clitoris, and basal and suprabasal in the epidermal cells membrane restricted to superficial sections of the labia minora. ER beta was found in the stroma of the labia minora closer to the clitoris and in superficial sections, in the basal epidermal cells membrane and apocrine glandular epithelial cells membrane. There was also ER beta cell membrane staining in the basal and suprabasal epithelial cells and fibroblasts in the lamina propria.
• Conclusions: Established ER presence allows the consideration of the introitus of the vagina as a target for oestrogen therapy in various clinical and surgical situations. Continuing elucidation of the immunohistochemistry of this external genital tissue might assist in the development of molecular tools to treat genital abnormalities. Details of this immunohistochemistry may also advance the understanding of the effects of sexual differentiation on the brain and other organ systems.
  
  
• Editorial Comment
  These interesting findings confirm our believe that labia minora and other vulvar tissues are estrogen target structures. It is our practice to administer local estrogen for treating labia minora fusion and other vulvar diseases in pre-pubertal, pre-menopausal and post-menopausal women. Also, the present data enable us to expect a greater estrogen effect when administered vaginally, compared with extravaginal administration, as the authors stated. These findings are of clinical importance in the pathophysiology of age-associated and hormonally associated female genital disorders that include both functional and structural changes.

Dr. Francisco J.B. Sampaio
Full-Professor and Chair, Urogenital Research Unit
State University of Rio de Janeiro
Rio de Janeiro, RJ, Brazil
E-mail: sampaio@urogenitalresearch.org