Exogenous Gonadotrophin Stimulation Induces Partial Maturation of Human Sertoli Cells in a Testicular Xenotransplantation Model for Fertility Preservation

Marsida Hutka,Rod T Mitchell,Ellen Goossens,Lee B Smith,Jan-Bernd Stukenborg,W Hamish B Wallace

doi:10.3390/jcm9010266

Abstract

The future fertility of prepubertal boys with cancer may be irreversibly compromised by chemotherapy and/or radiotherapy. Successful spermatogenesis has not been achieved following the xenotransplantation of prepubertal human testis tissue, which is likely due to the failure of somatic cell maturation and function. We used a validated xenograft model to identify the factors required for Leydig and Sertoli cell development and function in immature human testis. Importantly, we compared the maturation status of Sertoli cells in xenografts with that of human testis tissues (n = 9, 1 year-adult). Human fetal testis (n = 6; 14–21 gestational weeks) tissue, which models many aspects of prepubertal testicular development, was transplanted subcutaneously into castrated immunocompromised mice for ~12 months. The mice received exogenous human chorionic gonadotropin (hCG; 20IU, 3×/week). In xenografts exposed continuously to hCG, we demonstrate the maintenance of Leydig cell steroidogenesis, the acquisition of features of Sertoli cell maturation (androgen receptor, lumen development), and the formation of the blood–testis barrier (connexin 43), none of which were present prior to the transplantation or in xenografts in which hCG was withdrawn after 7 months. These studies provide evidence that hCG plays a role in Sertoli cell maturation, which is relevant for future investigations, helping them generate functional gametes from immature testis tissue for clinical application.

Highlights

Survival rates for childhood cancer have increased over recent decades as a result of advancements in detection and treatment [1]
In all (27/27) continuously human chorionic gonadotropin (hCG)-treated grafts, Sertoli cell proliferation had ceased (Figure 4U); Sertoli cell proliferation was maintained in 4/4 xenografts from the ‘Withdrawal hCG’ group (Figure 4T,V and Figure S1). These results suggest that the cessation of Sertoli cell proliferation occurs with the maturation of Sertoli cells in the human testis and that this can be promoted by continuous exposure to hCG in human fetal testis xenografts
We sought to investigate whether Sertoli cell maturation and Leydig cell steroidogenesis could be effectively induced by exposing human fetal testis to exogenous hCG in a xenotransplantation model, with a direct comparison to human testis tissues from fetal life, prepuberty, and adulthood

Summary

Introduction

Survival rates for childhood cancer have increased over recent decades as a result of advancements in detection and treatment [1]. A recent study involving non-human primate testis has provided proof of principle that the autotransplantation of prepubertal frozen-thawed testicular tissue might be a potential future fertility preservation strategy [6]. This approach has not been replicated in human studies and may not be safe for patients with haematological malignancies due to the risk of reintroducing malignant cells [7,8,9,10,11]. Subsequent fertility may require ex-situ differentiation of the immature germ cells present in prepubertal testis tissue into sperm, the latter can be used to generate offspring

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