Research Ruth Appeltant

Abstract

The earth faces unprecedented extinction levels, termed "the sixth extinction". Advanced assisted reproductive technology such as in vitro gametogenesis and cryobanking emerged as pivotal strategies in safeguarding the genetic diversity in mammalian species. However, oocyte scarcity, harvesting and cryopreservation challenges persist due to the absence of species-specific protocols. To save the genetics that could be forever lost, the use of somatic cells instead of reproductive tissues to generate offspring has been investigated. The most commonly investigated source of somatic cells are fibroblasts, but we will establish protocols for keratinocytes and mesenchymal stem cells which are expected to yield higher reprogramming efficiency and to anticipate situations where no fibroblasts are available. The goal is to provide biobanks with a variety of options depending on the available banked samples. While the ability to generate induced pluripotent stem cells (iPSCs) from different endangered mammalian species has been shown, the struggle to acquire a true endogenous pluripotent state of the reprogrammed cells remains. We propose a plasmid based transfection to provide a solid reprogramming. The generation of primordial germ cell-like cells from iPSCs and the creation of putative follicle structures is still in its infancy. By developing a co-culture system between primordial germ cell-like cells and ovarian somatic stem cells, we will develop a 3D ovaroid which will be able to create putative follicle structures. This project aims to bridge the gap between mice and wildlife applications by using the pig as a relevant animal model species. By enhancing our understanding of reproductive biology in this kind of model, this proposal will contribute to reversing biodiversity loss and aid wildlife population management.

Researcher(s)

• Promoter: Appeltant Ruth
• Fellow: Xie Jun

Research team(s)

• Veterinary physiology and biochemistry

Project type(s)

• Research Project

Abstract

Unfortunately, infertility problems around the world are alarmingly high. Several options are clinically available to women who are willing to preserve their fertility. Those techniques each have their own strengths and weaknesses. The fact that some patients can still not be helped by the currently available techniques requires research in new innovative areas that might provide solutions to all infertile animals or humans. The most promising approach to obtain oocytes without the need for the presence of own oocytes, is the creation of so called 'artificial' or in vitro created gametes from embryonic stem cells, from endogenous cells within the ovary or from induced pluripotent stem cells. Endogenous stem cells have been isolated from ovaries and their ability to differentiate into oocytes in vitro could be demonstrated for mice, but also for larger domestic animals such as sheep and juvenile pigs. Those cells will allow to create very substantial therapeutic applications by potentially allowing the formation of new oocytes. Going even a step further, there is the future perspective of using somatic cells such as skin biopsies to create induced pluripotent stem cells and turning those stem cells into germ cells such as oocytes and sperm cells. This would serve the extremely severe cases of infertility in which no patient-specific ovaries, follicles or oocytes are available. These techniques would not only give perspective to human fertility preservation, but could also lead to a breakthrough in conservation of endangered species. Considering porcine models are recognized worldwide as excellent models for human diseases and in vitro embryo production research, we will use the pig as a model to develop the stem cell techniques.

Researcher(s)

• Promoter: Appeltant Ruth
• Fellow: Appeltant Ruth

Research team(s)

• Veterinary physiology and biochemistry

Project type(s)

• Research Project

Abstract

In addition to already standardly applied procedures such as embryo-, oocyte- or ovarian tissue-cryopreservation, emerging techniques like fertoprotective adjuvant agents, in vitro grown oocytes or the creation of an artificial ovary are intensively researched in order to be able to provide solutions for every patient or animal in need of assisted reproductive help. Some of these strategies have since been shown to be effective, while others have the potential to provide new fertility preservation options, but they also each have their shortcomings. The drawbacks have led scientists and clinicians to search for alternative and more robust methods. The most promising approach is based on stem cells and would provide an alternative source of gametes for research as well as for infertility treatment or fertility preservation. Assisted reproductive techniques developed until now always rely on a certain supply of own follicles/oocytes. The specific characteristics of stem cells - undifferentiated cells able to transform into differentiated cells - open doors to produce so-called 'artificial' or in vitro created gametes, which can provide solutions exactly for those individuals lacking own oocytes. Therefore, this project focusses on developing techniques to isolate ovarian stem cells and to subsequently use those cells to generate female gametes or oocytes. The pig will be used as an animal model to bridge the gap between results obtained in mice and applications in human and endangered species.

Researcher(s)

• Promoter: Appeltant Ruth
• Fellow: Landeiro Filipe de Sousa Rita

Research team(s)

• Veterinary physiology and biochemistry

Project type(s)

• Research Project