title: Endometriosis is associated with aberrant endometrial expression of telomerase and increased telomere length.
abstract: BACKGROUND
  In order to test our hypothesis that endometriosis is associated with abnormal expression of telomerase and telomere lengthening in endometrium, we assessed endometrial expression of the human telomerase enzyme and telomere length (TL).
  
  
  METHODS
  This prospective pilot study, included 29 women with symptomatic, surgically diagnosed endometriosis (Group 1) and 27 healthy, fertile, symptom-free women without endometriosis (Group 2, confirmed by laparoscopy). Seventeen women in Group 1 and 15 women in Group 2 had endometrial biopsies taken on Day 21 +/- 2 of the cycle. A further 12 women in each group were biopsied on Day 26 +/- 2. Telomerase and estrogen receptor beta (ERbeta) expression was evaluated by immunohistochemistry. Mean TL was determined by quantitative PCR.
  
  
  RESULTS
  The endometria of fertile healthy women showed either weak or no telomerase immunoreactivity throughout the luteal phase. Immunostaining for telomerase was significantly increased during the implantation window and the premenstrual endometria of women with endometriosis (P < 0.0001). This was associated with a loss of stromal and vascular ERbeta immunostaining (P < 0.05). The mean TL were significantly longer in endometria of women with endometriosis during the implantation window (P = 0.005), indicating the biological relevance of our novel finding of telomerase in benign endometrium. There was positive correlation of the circulating estradiol with peripheral blood TL in women.
  
  
  CONCLUSIONS
  We speculate that aberrant endometrial expression of telomerase mediates alterations in cell fate that enhance proliferation, contributing to the pathogenesis of endometriosis.
authors.affiliation: School of Reproductive and Developmental Medicine, University of Liverpool, Liverpool Women's Hospital, Crown Street, Liverpool L8 7SS, UK. dharani.hapangama@liverpool.ac.uk
authors.forename: D K
authors.initials: DK
authors.lastname: Hapangama
authors.forename: M A
authors.initials: MA
authors.lastname: Turner
authors.forename: J A
authors.initials: JA
authors.lastname: Drury
authors.forename: S
authors.initials: S
authors.lastname: Quenby
authors.forename: G
authors.initials: G
authors.lastname: Saretzki
authors.forename: C
authors.initials: C
authors.lastname: Martin-Ruiz
authors.forename: T
authors.initials: T
authors.lastname: Von Zglinicki
mesh_terms: D000293:Adolescent; D000328:Adult; D004715:Endometriosis / Q000503:physiopathology*; D004717:Endometrium / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000096:biosynthesis; D005260:Female; D015870:Gene Expression / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D019098:Telomerase / Q000096:biosynthesis*; D016615:Telomere / Q000648:ultrastructure*
chemical_list: D047629:Estrogen Receptor beta; D019098:Telomerase