title: Comparison of the vaginal environment of Macaca mulatta and Macaca nemestrina throughout the menstrual cycle.
abstract: OBJECTIVE
  Pigtail macaques, Macaca nemestrina (PT), are more susceptible to vaginal transmission of simian immunodeficiency virus (SIV) and other sexually transmitted diseases (STD) than rhesus macaques (RM). However, comparative studies to explore the reasons for these differences are lacking.
  
  
  METHODS
  Here, we compared differences in hormone levels and vaginal mucosal anatomy and thickness of RM and PT through different stages of the menstrual cycle. Concentrations of plasma estradiol (E2) and progesterone (P4) were determined weekly, and vaginal biopsies examined at days 0 and 14 of the menstrual cycle.
  
  
  RESULTS
  Consistent changes in vaginal epithelial thickness occurred at different stages of the menstrual cycle. In both species, the vaginal epithelium was significantly thicker in the follicular than in luteal phase. Keratinized epithelium was strikingly much more prominent in RM, especially during the luteal phase. Further, the vaginal epithelium was significantly thinner, and the P4:E2 ratio was higher in PT during luteal phase than RM.
  
  
  CONCLUSIONS
  Striking anatomic differences in the vaginal epithelium between rhesus and pigtail macaques combined with differences in P4:E2 ratio support the hypothesis that thinning and less keratinization of the vaginal epithelium may be involved in the greater susceptibility of pigtail macaques to vaginal transmission of SIV or other STD.
authors: Tulane National Primate Research Center, Covington, LA, USA.
authors: Sarah V
authors: SV
authors: Hadzic
authors: Xiaolei
authors: X
authors: Wang
authors: Jason
authors: J
authors: Dufour
authors: Lara
authors: L
authors: Doyle
authors: Preston A
authors: PA
authors: Marx
authors: Andrew A
authors: AA
authors: Lackner
authors: Daniel B
authors: DB
authors: Paulsen
authors: Ronald S
authors: RS
authors: Veazey
mesh_terms: D000818:Animals; D004198:Disease Susceptibility; D004958:Estradiol / Q000097:blood; D005260:Female; D005498:Follicular Phase / Q000502:physiology*; D008183:Luteal Phase / Q000502:physiology*; D008253:Macaca mulatta / Q000502:physiology*; D008254:Macaca nemestrina / Q000502:physiology*; D009092:Mucous Membrane / Q000033:anatomy & histology / Q000502:physiology; D011374:Progesterone / Q000097:blood; D016097:Simian Acquired Immunodeficiency Syndrome / Q000635:transmission; D015302:Simian Immunodeficiency Virus / Q000472:pathogenicity; D014621:Vagina / Q000033:anatomy & histology* / Q000502:physiology
chemical_list: D011374:Progesterone; D004958:Estradiol
keywords: Epithelium; Macaca nemestrina; SIV/HIV transmission; estradiol; menstrual cycle; mucosa; progesterone; rhesus macaque; vagina