Role of Insulin-like growth factors in initiation of follicle growth in normal and polycystic human ovaries.

CONTEXT: Polycystic ovary syndrome (PCOS), the commonest cause of anovulatory infertility, is characterized by disordered follicle development including increased activation and accelerated growth of preantral follicles. Data from experimental animals and preliminary results from studies of human ovarian tissue suggest that IGFs affect preantral follicle development. OBJECTIVE: Our objectives were to investigate the expression of the type-1 IGF receptor (IGFR-1) in the human ovary and to determine whether IGFs are involved in stimulating the transition of follicles from primordial to primary stage in normal and polycystic ovaries. DESIGN: We used archived ovarian tissue for protein expression studies and small cortical biopsies for follicle isolation and for tissue culture. SETTING: This was a laboratory-based study, using clinical tissue samples. PATIENTS: A total of 54 women, 33 with normal ovaries and 21 with polycystic ovaries, were classified by reference to menstrual cycle history and ultrasonography. MAIN OUTCOME MEASURES: We evaluated expression of IGFR-1 mRNA in isolated preantral follicles and of IGFR-1 protein in archived ovarian tissue samples from normal and polycystic ovaries and effects of exogenous IGF-1 on preantral follicle development and survival in cultured fragments of normal and polycystic ovaries. RESULTS: IGFR-1 mRNA and protein was expressed in preantral follicles at all stages of development and enhanced expression was noted in PCOS follicles during early preantral development. IGF-1 stimulated initiation of follicle growth in normal tissue but had little effect on preantral follicle growth in polycystic ovaries in which, characteristically, there was a higher proportion of follicles that had entered the growing phase even before culture. CONCLUSIONS: IGFs are plausible candidates in regulation of initiation of human follicle growth, and accelerated preantral follicle growth in PCOS may be due to increased activity of endogenous IGFs.

Abnormal preantral folliculogenesis in polycystic ovaries is associated with increased granulosa cell division.

CONTEXT: Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women, but its etiology remains obscure. Recent data suggest that an intrinsic abnormality of early follicle development in the ovary is key to the pathogenesis of PCOS. We have recently found that in PCOS the proportion of primordial follicles is decreased with a reciprocal increase in the proportion of primary follicles. OBJECTIVE: Our aim was to examine whether the accelerated transition of follicles from primordial to primary stages in polycystic ovaries (PCO) is due to increased granulosa cell (GC) division. DESIGN: This study is a comparison of expression of minichromosome maintenance protein 2 (MCM2) (present in the nuclei of cells that are licensed to divide) in archive tissue from normal and PCO. SETTING: This is a laboratory-based study. PATIENTS: There were 16 women with regular cycles (six with normal and 10 with PCO) and five anovulatory women with PCO, classified histologically, with reference to menstrual history and ultrasound. MAIN OUTCOME MEASURES: The presence of MCM2 expression in the GCs of 1,371 follicles was determined. RESULTS: GC proliferation was increased in anovulatory PCO compared with both normal and ovulatory PCO, with an increased proportion of preantral follicles with MCM2-positive GCs (P

Prolonged survival in culture of preantral follicles from polycystic ovaries.

CONTEXT: In polycystic ovary syndrome (PCOS), an increased proportion of follicles leave the primordial (resting) pool and initiate growth. However, there is little evidence for a reduced reproductive life span (early menopause) in women with PCOS, suggesting that the dynamics of follicle growth, and of follicle loss by atresia, is altered in PCOS. OBJECTIVE: The aim of this study was to investigate the possibility that loss of preantral follicles by atresia is reduced in PCOS, leading to prolonged follicle survival. DESIGN: We compared follicle growth in normal and polycystic ovaries using cultures of small ovarian biopsies. SETTING: Tissue samples were obtained at routine laparoscopy from 12 patients with anovulatory PCOS and 16 controls and processed in an ovarian physiology laboratory. MAIN OUTCOME MEASURES: We performed morphometric analysis of follicle population in tissue fixed at time of biopsy (d 0) or after 5, 10, or 15 d in culture. Analyses included assessment of follicle and oocyte diameter, number and proportion of primordial and growing follicles, and number and proportion of atretic follicles. RESULTS: In tissue fixed on d 0, the proportion of healthy growing follicles was, as expected, greater in ovaries from PCOS patients than in normal ovaries (64 vs. 28%; P = 0.0005), but there were no differences between PCOS and normal tissue during culture. The rate of atresia throughout the period of culture in follicles was, however, significantly lower in PCOS tissue (P < 0.0001). After culture, 80% of follicles in normal ovarian tissue were atretic compared with 53% in PCOS biopsies. CONCLUSION: Follicles from polycystic ovaries demonstrate a decreased rate of atresia in culture, suggesting a mechanism for maintaining a larger follicle pool throughout reproductive life.

Anti-müllerian hormone protein expression is reduced during the initial stages of follicle development in human polycystic ovaries.

CONTEXT: Polycystic ovary syndrome, the most common cause of anovulatory infertility, is characterized by disordered folliculogenesis, notably increased progression from the primordial to the primary stages. This ovarian phenotype is similar to that observed in mice lacking anti-müllerian hormone (AMH). OBJECTIVE: The objective of this study is to investigate whether AMH is involved in accelerating the transition of follicles from primordial to primary stages in polycystic ovaries. DESIGN: This study compares AMH expression in archive tissue from normal and polycystic ovaries. SETTING: This is a laboratory-based study. PATIENTS: Ovarian tissue from seven normoovulatory women and 16 women with polycystic ovaries (five of whom were anovulatory) was used in this study. Ovaries were classified by histology and with reference to menstrual cycle history and ultrasound. MAIN OUTCOME MEASURE: Presence and intensity of AMH expression in 1403 follicles was the main outcome measure. RESULTS: AMH was observed from the primordial stage onward. AMH immunostaining was observed in significantly fewer primordial (P = 0.007) and transitional follicles (P = 0.001) in ovaries from anovulatory women with polycystic ovaries compared with women with regular cycles and either normal or polycystic ovaries. AMH-negative follicles had fewer pregranulosa cells in the largest cross-section of the follicle at both the primordial (median, four and six for AMH-negative and -positive follicles, respectively; P < 0.0001) and transitional stages (median six and nine; P < 0.0007) in normal tissue, and fewer at the transitional stage (median, seven and 11; P < 0.0001) in tissue from anovulatory women with polycystic ovaries. This suggests that AMH expression is associated with granulosa cell mitosis. CONCLUSIONS: These findings indicate a relative deficiency of AMH in primordial and transitional follicles in ovaries from anovulatory women with polycystic ovaries. This may contribute to disordered early follicle development in polycystic ovary syndrome.