The immature human ovary shows loss of abnormal follicles and increasing follicle developmental competence through childhood and adolescence

• Published in: Human reproduction (Oxford) 2014-01, Vol.29 (1), p.97-106
• Main Authors: Anderson, R.A., McLaughlin, M., Wallace, W.H.B., Albertini, D.F., Telfer, E.E.
• Format: Article
• Language: English
• Subjects: Adolescent; Adolescents; Adult; Biopsy; Child; Child, Preschool; Cryopreservation; Female; Fertility Preservation; Humans; Oocytes - growth & development; Oocytes - pathology; Original; Ovarian Follicle - growth & development; Ovarian Follicle - physiology; Ovary - pathology; Puberty; Sexual Maturation - physiology; Tissue Culture Techniques
• ISSN: 0268-1161; 1460-2350
• DOI: 10.1093/humrep/det388

STUDY QUESTION Do the ovarian follicles of children and adolescents differ in their morphology and in vitro growth potential from those of adults? SUMMARY ANSWER Pre-pubertal ovaries contained a high proportion of morphologically abnormal non-growing follicles, and follicles showed reduced capacity for in vitro growth. WHAT IS KNOWN ALREADY The pre-pubertal ovary is known to contain follicles at the early growing stages. How this changes over childhood and through puberty is unknown, and there are no previous data on the in vitro growth potential of follicles from pre-pubertal and pubertal girls. STUDY DESIGN, SIZE, DURATION Ovarian biopsies from five pre-pubertal and seven pubertal girls and 19 adult women were analysed histologically, cultured in vitro for 6 days, with growing follicles then isolated and cultured for a further 6 days. PARTICIPANTS/MATERIALS, SETTING, METHODS Ovarian biopsies were obtained from girls undergoing ovarian tissue cryopreservation for fertility preservation, and compared with biopsies from adult women. Follicle stage and morphology were classified. After 6 days in culture, follicle growth initiation was assessed. The growth of isolated secondary follicles was assessed over a further 6 days, including analysis of oocyte growth. MAIN RESULTS AND THE ROLE OF CHANCE Pre-pubertal ovaries contained a high proportion of abnormal non-growing follicles (19.4 versus 4.85% in pubertal ovaries; 4004 follicles analysed; P = 0.02) characterized by indistinct germinal vesicle membrane and absent nucleolus. Follicles with this abnormal morphology were not seen in the adult ovary. During 6 days culture, follicle growth initiation was observed at all ages; in pre-pubertal samples there was very little development to secondary stages, while pubertal samples showed similar growth activation to that seen in adult tissue (pubertal group: P = 0.02 versus pre-pubertal, ns versus adult). Isolated secondary follicles were cultured for a further 6 days. Those from pre-pubertal ovary showed limited growth (P < 0.05 versus both pubertal and adult follicles) and no change in oocyte diameter over that period. Follicles from pubertal ovaries showed increased growth; this was still reduced compared with follicles from adult women (P < 0.05) but oocyte growth was proportionate to follicle size. LIMITATIONS, REASONS FOR CAUTION These data derive from only a small number of ovarian biopsies, although large numbers of follicles were analysed. It is unclear whethe