Impaired in vitro fertilization outcomes following testosterone treatment improve with washout in a mouse model of gender-affirming hormone treatment

Reproductive Health in Trans and Gender Diverse Patients: Effects of transmasculine gender-affirming hormone therapy on future reproductive capacity: clinical data, animal models, and gaps in knowledge

In brief

Animal studies are needed to inform clinical guidance on the effects of testosterone gender-affirming hormone therapy (T-GAHT) on fertility. This review summarizes current animal models of T-GAHT and identifies gaps in knowledge for future study.

Abstract

Testosterone gender affirming hormone therapy (T-GAHT) is frequently used by transgender and gender-diverse individuals assigned female at birth to establish masculinizing characteristics. Although many seek parenthood, particularly as a gestational parent or through surrogacy, the current standard guidance of fertility counseling for individuals on testosterone (T) lacks clarity. At this time, individuals are typically recommended to undergo fertility preservation or stop treatment, associating T-therapy with a loss of fertility; however, there is an absence of consistent information regarding the true fertility potential for transgender and gender-diverse adults and adolescents. This review evaluates recent studies that utilize animal models of T-GAHT to relate to findings from clinical studies, with a more specific focus on fertility. Relevant literature based on murine models in post- and pre-pubertal populations has suggested reversibility of the impacts of T-GAHT, alone or following gonadotropin-releasing hormone agonist (GnRHa), on reproduction. These studies reported changes in clitoral area and ovarian morphology, including corpora lutea, follicle counts, and ovarian weights from T-treated mice. Future studies should aim to determine the impact of the duration of T-treatment and cessation on fertility outcomes, as well as establish animal models that are clinically representative of these outcomes with respect to gender diverse populations.

Reproductive Considerations in the Transgender and Gender Diverse Population: A Review

Many transgender and gender diverse (TGD) individuals will be considering gender-affirming treatments during their reproductive lifespan. These medically necessary treatments have a negative impact on reproductive potential. All TGD individuals should be counseled regarding fertility. Options for fertility preservation for individuals who have undergone puberty include mature oocyte, embryo, and sperm cryopreservation. In prepubertal individuals, ovarian tissue cryopreservation may be considered, but testicular tissue cryopreservation remains experimental only. While there have been advances in the technology and standardization of reproductive health care for this population, many gaps remain in our knowledge which require further research.

Androgen Inhibition of Reproductive Neuroendocrine Function in Females and Transgender Males

Ovarian function is controlled by pituitary secretion of luteinizing hormone (LH) and follicle stimulating hormone (FSH), which in turn are governed by gonadotropin releasing hormone (GnRH) secreted from the brain. A fundamental principle of reproductive axis regulation is negative feedback signaling by gonadal sex steroids back to the brain to fine-tune GnRH and gonadotropin secretion. Endogenous negative feedback effects can be mimicked by exogenous steroid treatments, including androgens, in both sexes. Indeed, a growing number of clinical and animal studies indicate that high levels of exogenous androgens, in the typically male physiological range, can inhibit LH secretion in females, as occurs in males. However, the mechanisms by which male-level androgens inhibit GnRH and LH secretion still remain poorly understood, and this knowledge gap is particularly pronounced in transgender men (individuals designated female at birth but identifying as male). Indeed, many transgender men take long-term gender-affirming hormone therapy that mimics male-level testosterone levels. The impact of such gender-affirming testosterone on the reproductive axis, both at the ovarian and neuroendocrine level, is a long-understudied area that still requires further investigation. Importantly, the few concepts of androgen actions in females mostly come from studies of polycystic ovary syndrome, which does not recapitulate a similar androgen milieu or a pathophysiology of inhibited LH secretion as occurs in testosterone-treated transgender men. This review summarizes clinical evidence indicating that exogenous androgens can impair neuroendocrine reproductive function in both female individuals and transgender men and highlights emerging experimental data supporting this in recently developed transgender rodent models.

Evaluation of Lipids and Lipid-Related Transcripts in Human and Ovine Theca Cells and an in Vitro Mouse Model Exposed to the Obesogen Chemical Tributyltin

BACKGROUND

Exposure to obesogenic chemicals has been reported to result in enhanced adipogenesis, higher adipose tissue accumulation, and reduced ovarian hormonal synthesis and follicular function. We have reported that organotins [tributyltin (TBT) and triphenyltin (TPT)] dysregulate cholesterol trafficking in ovarian theca cells, but, whether organotins also exert lipogenic effects on ovarian cells remains unexplored.

OBJECTIVE

We investigated if environmentally relevant exposures to organotins [TBT, TPT, or dibutyltin (DBT)] induce lipid dysregulation in ovarian theca cells and the role of the liver X receptor (LXR) in this effect. We also tested the effect of TBT on oocyte maturation and neutral lipid accumulation, and lipid-related transcript expression in cumulus cells and preimplantation embryos.

METHODS

Primary theca cell cultures derived from human and ovine ovaries were exposed to TBT, TPT, or DBT (1, 10, or 50   ng / ml ). The effect of these chemical exposures on neutral lipid accumulation, lipid abundance and composition, lipid homeostasis-related gene expression, and cytokine secretion was evaluated using liquid chromatography-mass spectrometry (LC-MS), inhibitor-based methods, cytokine secretion, and lipid ontology analyses. We also exposed murine cumulus-oocyte complexes to TBT and evaluated oocyte maturation, embryo development, and lipid homeostasis-related mRNA expression in cumulus cells and blastocysts.

RESULTS

Exposure to TBT resulted in higher intracellular neutral lipids in human and ovine primary theca cells. In ovine theca cells, this effect was dose-dependent, independent of cell stage, and partially mediated by LXR. DBT and TPT resulted in higher intracellular neutral lipids but to a lesser extent in comparison with TBT. More than 140 lipids and 9 cytokines were dysregulated in TBT-exposed human theca cells. Expression of genes involved in lipogenesis and fatty acid synthesis were higher in theca cells, as well as in cumulus cells and blastocysts exposed to TBT. However, TBT did not impact the rates of oocyte maturation or blastocyst development.

DISCUSSION

TBT induced dyslipidemia in primary human and ovine theca cells, which may be responsible for some of the TBT-induced fertility dysregulations reported in rodent models of TBT exposure. https://doi.org/10.1289/EHP13955.

A Review of Animal Models Investigating the Reproductive Effects of Gender-Affirming Hormone Therapy

Gender-affirming hormone therapy (GAHT) is an important component in the process of transitioning for many transgender and gender-diverse (TGD) individuals. Multiple medical organizations recommend fertility preservation counseling prior to initiation of GAHT; however, there remains little high-quality data regarding the impact of GAHT on fertility and reproductive function. A PubMed literature review was performed using Boolean search operators linking keywords or phrases such as "mouse", "rat", "primate", "animal model", "transgender", "gender", "estrogen", "testosterone", "fertility", and "fertility preservation". Recent research has produced a number of animal models of GAHT that utilize similar hormonal regimens and produce similar phenotypic results to those used and observed in human patients. Specific to testosterone(T)-containing GAHT, animals demonstrate loss of menstrual cyclicity with therapy, resumption of menses on cessation of therapy, suppression of gonadotropin levels, and physical changes such as clitoromegaly. Models mimicking GAHT for transmasculine individuals in the peripubertal period demonstrate that pretreatment with GnRHa therapy does not modify the effects of subsequent T administration, which were similar to those described in adult models. Both models suggest promising potential for future fertility with cessation of T. With estradiol (E)-containing GAHT, animals exhibit decreased size of testicles, epididymis, and seminal vesicles, as well as ongoing production of spermatocytes, and seminiferous tubule vacuolization. Given the ethical challenges of conducting human studies in this area, high-fidelity animal models represent a promising opportunity for investigation and could eventually transform clinical counseling about the necessity of fertility preservation. Future studies should better delineate the interactions (if any exist) between treatment attributes such as dosing and duration with the extent of reversibility of reproductive perturbations. The development of models of peripubertal feminizing GAHT is an additional area for future work.

Barriers to fertility preservation access in transgender and gender diverse adolescents: a narrative review

Fertility preservation (FP) involves the cryopreservation of gametes, embryos, and/or gonadal tissue oocytes, for future use in family building. FP as part of a comprehensive approach to care of transgender and gender diverse (TGD) individuals is an understudied topic. Current evidence indicates that gender affirming therapies may increase the risk for infertility. As a result, TGD individuals, including adolescents, should receive counseling regarding FP prior to beginning gender affirming treatment. Many barriers exist to TGD adolescents receiving FP counseling and undergoing FP if desired. The objective of this narrative review is to summarize the literature regarding the desire for FP in TGD adolescents, the barriers to TGD adolescents in accessing of FP, and to discuss potential interventions for alleviation of such barriers. A literature search using the following Medical Subject Headings search terms: 'transgender persons' and 'fertility preservation' and 'adolescents' was conducted via searching PubMed. Additional articles were located via reference review. Included articles consist of qualitative and quantitative research and society guidelines. Articles from inception to 1st July 2023 were included. The results of the literature search have been summarized into the format of a narrative review. Key barriers to FP for TGD adolescents include inconsistencies in form and timing of counseling, potential worsening of gender dysphoria with FP treatment, high cost of treatment, limited research on FP outcomes, and legal barriers. Intersectionality between gender identity and other forms of minority status can compound these barriers to FP and healthcare in general. Barriers to TGD adolescents accessing FP are significant. Increased research is needed upon methods to mitigate these barriers. Solutions include increasing uniformity and timing of FP counseling by varying health care providers, advocacy efforts to mitigate legal and financial barriers, increased research efforts in FP outcomes, and increased cultural competency in clinics offering FP care to TGD adolescents.