Optimisation of fertility cryopreservation in females
: from in vitro fertilization to in vitro maturation to in vitro culturing

Student thesis: Doctoral Thesis

Abstract

The dissertation presents my published studies investigating the optimisation of the different fertility cryopreservation modalities in females- from In vitro Fertilization to In Vitro Maturation to ovarian tissue cryopreservation and in Vitro culturing. We aim at presenting the advancement of fertility preservation options for paediatric, adolescent and reproductive aged female patients. The studies include 16 peer reviewed journal articles, two poster abstracts, three book chapters in addition to two additional articles in submission. These studies cover my academic career while working in the Hebrew University of Jerusalem and Oxford University during the last 20 years.
The dissertation includes my research on:

1. The basic reproductive physiology and infertility- this will include two book chapters in female reproductive endocrinology and pathophysiology and investigations of female infertility and a basic science study on poor ovarian responders, done in an attempt to find the pathophysiologic basis of this group of patients. We found that granulosa cells from elderly poor responders showed normal mitochondrial membrane potential and normal endocrinologic function as presented by JC-1 (5,5′,6,6′-tetrachloro-1,1′,3,3′tetraethylbenzimidazolylcarbocyanine iodide) mitochondrial stain and the StAR and side chain cleavage enzyme levels. We have shown that low follicular phase oestrogen levels induced by aromatase inhibitors do not play a deleterious effect on folliculogenesis and that oestrogen levels per se are not critical for folliculogenesis in the mice ovaries. In addition, embryos created and cultured showed normal development in culture as shown by satisfactory progression to advanced embryonal forms i.e. the morula and blastocyst stages. We then suggested the safety of aromatase inhibitors utilised for superovulation in cancer patients.
2. In Vitro Fertilization (IVF) followed by embryo or eggs freeze as a well-established modality. We present several studies done, including the confirmation of random start ovulation induction protocol, the safety of egg collections in patients having haemostatic disorders which is a common condition in cancer patients, embryonal biomarkers as predictors of implantation outcomes and clinical pregnancy rates and our contribution in the study of the different protocols utilised in frozen embryo replacement cycles, which are the mainstay of the fertility treatment after patients recover from their cancer treatment and return for embryo transfer.
3. The development of In Vitro Maturation (IVM) and its embodiment in the fertility preservation programme, as a standalone option and also as a complementary modality, together with IVF or ovarian tissue preservation options. I will present my work in this area including comparison of IVM and IVF results, using IVM and surrogacy in Ehler Danlos disease and utilisation of IVM in under responding or over responding PCOS patients. The adoption of IVM is of importance in any fertility preservation programme, as a standalone or a complementary modality.
4. Ovarian Tissue Cryopreservation as a modality in prepubertal girls or adult patients who need to proceed urgently to chemotherapy. This work culminated in setting up ovarian tissue banking in Oxford including developing protocols, policies and nationwide clinical service. I have worked on the establishment of one of the UK's first HTA/HFEA approved ovarian tissue cryopreservation programme which offers cancer patients from across the country in a hub and spoke model to have ovarian cryopreservation. A chapter in the book will be presented as well as a manuscript summarising our experience will be submitted for publication to report the first 100 patients referred to this important translational programme.
5. In vitro culture of ovarian tissue as a future fertility preservation option. We investigated the developmental staging of the different follicles in human cryopreserved ovarian tissue from patients undergoing fertility preservation. Our findings showed a variation in follicular developmental stages and their health in both cultured and non-cultured ovarian tissue. Our study reported a new classification system of follicles health in human cryopreserved ovarian tissue, based on the presence/absence of pyknosis in granulosa cells, pyknosis in oocytes and the presence or absence of shrunken cytoplasm.

These publications contributed to the adoption of well-established fertility preservation techniques as well as the innovative and experimental technique of ovarian tissue preservation that was adopted and offered to patients. My work helped to start basic science and biomedical studies to further the development of fertility preservation options in female cancer patients. Future horizons of my work would be in developing techniques of in vitro culturing of follicles, reaggregated ovaries and the biofabricated ovary.
Date of Award2021
Original languageEnglish
SupervisorGraham Mills (Supervisor)

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