title: Impact of testosterone on the non-growing follicles and stroma in the transgender ovary
title: The impact of testosterone on the non-growing follicles and stroma in the transgender ovary
titleType: AlternativeTitle
Creators: name: Bailie, Emily
Publisher: name: The University of Edinburgh
Year: 2024
Subjects: transgender
testosterone
non-growing ovarian follicles
primordial follicles
effect
impact

description: There is an increasing awareness of a need for fertility preservation measures for the transgender population prior to commencing gender affirming endocrine therapy. Current options for transgender men include embryo and oocyte cryopreservation but ovarian tissue cryopreservation may be a viable fertility preservation option for transgender men if immature follicles from removed ovarian cortex could be developed in vitro to maturity. However, there are few data on the effect of long-term exposure to high levels of testosterone as found in transgender men taking testosterone therapy on the non-growing follicles of the ovary. Androgens are essential in normal ovarian function and follicle health, with androgen receptor expression found on the granulosa and theca cells as well as the oocyte. Androgens promote follicle growth, improve the responsiveness of granulosa cells to FSH and are an essential substrate for oestradiol production. However, an excess of androgen, as seen in polycystic ovary syndrome (PCOS), is associated with increased follicular recruitment with subsequent development arrest and anovulation, poor ovarian follicle health and subfertility. Hyperandrogenism as seen in PCOS and transgender men on testosterone therapy also drives changes within the ovarian stroma including thickening of the tunica albuginea, stromal cell hyperplasia and stromal cell luteinisation, contributing to reduced follicle maturation. In this study, the effect of testosterone on the development, morphological health and DNA damage and repair capacity of human ovarian follicles in vivo and their survival in vitro was investigated. Potential alterations in the composition of the ovarian stroma as a result of testosterone exposure and how this can impact follicle growth and activation were also investigated. Whole ovaries were obtained from transgender men taking pre-operative testosterone therapy (mean age: 27.6 ± 1.7 years; range 20-34 years, n = 8) at oophorectomy. This was compared to cortical biopsies from age-matched healthy women obtained at caesarean section (mean age: 31.8±1.5 years; range= 25-35 years, n=8). Cortical tissues were dissected into fragments and either fixed immediately for histological analysis or cultured for 6 days and subsequently fixed. Follicle classification and morphological health were evaluated from histological sections stained with haematoxylin and eosin (H&amp;E) and expression of γH2AX as a marker of DNA damage by immunohistochemistry. Alteration of the composition of the ovarian stroma compared to control ovarian cortex was assessed by quantifying collagen deposition using histological stains picrosirius red and Masson’s Trichrome, and elastin deposition using immunofluorescence. Stromal cell density was quantified from H&amp;E stained sections. In uncultured tissue, testosterone exposure was associated with reduced follicle growth activation, poor follicle health and increased DNA damage. After 6 days of culture, there was enhanced follicle activation compared to control, but with further deterioration in morphological health and increased DNA damage. Transgender ovarian tissue had more collagen and less elastin compared to control with a subsequently higher collagen/elastin ratio, indicating tissue fibrosis. The stromal cell density was significantly higher in transgender tissue, in keeping with stromal cell hyperplasia. The findings from this study indicate that high circulating concentrations of testosterone have effects on the primordial and small-growing follicles of the ovary. In addition, it was found that the ovaries of transgender men are more collagenous and less elastic, indicating tissue fibrosis. This enhanced tissue rigidity may contribute to reduced follicle activation in vivo and have implications on reproductive outcomes for transgender men considering pregnancy or fertility preservation measures.