Is using stem cells to grow new eggs an effective alternative method of fertility treatment for infertile couples?

by beccilybum (student)

Is using stem cells to grow new eggs an effective alternative method of fertility treatment for infertile couples?

Rebecca Jones

Introduction

Infertility rates are set to rise, currently one in seven couples are struggling to conceive within 12 months and this is predicted to rise to one in three in the future [1]. Infertility affects about 10% of all women (Figure 2) and can appear in one of the many forms. The most common forms are hormonal and are linked to ovulation; not ovulating regularly or at all. A common example of hormonal-dependent infertility is polycystic ovarian syndrome (PCOS), a hormone imbalance interfering with normal ovulation, which reduces fertility.

In situations where ovulation can be encouraged by hormones, like PCOS then there is a moderate chance of women will still be able to conceive naturally (45% to 50%.) [9]. However, not all women are able to encourage ovulation with hormones, these people have a few options: in vitro fertilisation (IVF), surrogacy, sperm and egg donation. Of these, IVF is the most common method used to solve infertility, but success rates are low (Table 1) in comparison to the chances of getting pregnant naturally when fertile (Figure 2) People who are unable to produce the necessary reproductive cells but still want to carry their own children are pushed toward using sperm and egg donation. Unfortunately this means the child will not biologically belong to one or both of the parents.

Currently, a new method is being developed to try and give couples (who don’t have the necessary reproductive cells) the ability to produce a child that is genetically theirs using stem cells. Stem cell technology has the potential to offer an alternative to established methods of infertility treatment by growing new reproductive cells from the patient’s own tissues. This technology therefore offers couples in which one or both partners are sterile the ability to have child which is genetically their own. Also this may offer higher success rates than methods such as IVF as the egg will biologically belong to the mother it reduces the chances of rejection from the maternal immune system [3].

Table 1: IVF Success Rates with non-donor eggs (2007)

[2]

Infertility rates in comparison to naturally conceiving

Main Solution

Using recent breakthroughs in stem cell technology there is now the possibility to grow infertile couples either sperm or ova in a laboratory.

Stem cells are a specialist form of cell, which can become any of the cells in the body. When they divide, stem cells split into two different daughter cells. One of these is a progenitor cell which can go on to become another body cell (such as a blood cell) and the other is a new stem cell. In this way the stem cell is self-renewing and keeps on producing new body cells (Fig. 3). The ability of stem cells to become any other cell means that in they are currently used in stem cell therapies but a lot of stem cell therapies are currently just promising research. However, stem cells are currently used in treatment for leukemia, indicating that using stem cells as a solution to serious problems is a viable soloution. In the future they could be used to grow new organs for humans, including reproductive cells.

Password

Confirm Password

I agree to the terms of service and privacy policy

Figure 3[9]

Applied Biology

This is a preview of the whole essay

Figure 3[9]

Applied Biology

Stem cells are very rare and must be collected from skin or blood taken from a human donor. Currently the most common way of making stem cells is to reprogram stem cell taken from skin to make induced pluripotent stem cells (iPSC). Induced pluripotent stem cells are adult stem cells that have been reprogrammed to give the function of an embryonic stem cell by being forced to express the genes and factors vital for maintaining the defining properties of the embryonic stem cell (6). A plug of skin (approx. 2mm in diameter) is taken, put in a petri dish, and the layer of fat from underneath removed leaving just the layer of skin and stem cells. These cell are grown (see figure 3) for approximately four months until all the other cells have died off, leaving just the stem cells. [3] [7].

Since stem cells have the ability to grow in to many different kind of cells found within the body and are potentially capable of becoming an egg and therefore helping infertile couples. The cell that a stem cell becomes is dependent on the body or experimental conditions they are placed it [5]. In order to create an egg which can be used for fertilization, induced pluripotent stem cells can be converted to eggs. Whilst this is not yet been done in humans it has been done in mice, by a team of scientists including Katsuhiko Hayashi at the Kyoto University. In this work they took a section of mouse ovary (not necessarily from the intended biological mother) placed it in a petri dish with the IPS cells from the mice, and from this grew mouse eggs. These eggs were then fertilized in vitro and implanted into a mouse. The experiment was of relative success, 27.5% of all embryos implanted gave litters of healthy pups which were fertile themselves. For an experiment in the early stages of development, it gives good stead for research in the future. [7]

Although the theory of trying to use stem cells to produce the reproductive cells is currently a well informed theory, the use of IPSC’s have already been used in humans [6], giving scientists further reason to believe the use of this fertility treatment could be viable in the future. This is the current state of play as far as the technology has gone. It has not yet been proven in humans. Dr Hayashi has said "I must say that it is impossible to adapt immediately this system to human stem cells’’ but Prof Robert Norman, from the University of Adelaide said "Application to humans is still a long way off, but for the first time the goal appears to be in sight." [1]

Implications

Using this method is beneficial to humans as it could potentially give the capability of having biological children; when they aren’t producing the necessary reproductive cells conceive a child naturally. It also gives the potential, in women, overcoming menopause by producing eggs artificially that they are no longer capable of. Once the egg is implanted, this new method could theoretically reduce the risks of rejection from the maternal immune system, as it is genetically hers, giving better success rates then the current IVF methods. Limiting factors for this solution is the fact that it is not currently available for use in humans as the technology has not been tested or used in humans yet and it could be a long way off. However, scientists are confident it will be applicable to humans in the future [1].

The fact that this technology could give women, well past their childbearing years (women who are past the menopause) has surprisingly raised economical issues. Currently women are having children slightly later in their life to put their career first, affecting the population structure of the country (e.g. the UK). If women are having children later and later because they can wait until after their menopause, it may cause economic issues for the country, as it will lead to an aging population because there isn’t enough working population to support the dependant population, costing the country millions in pensions etc. because there isn’t enough of a working population to support them.

Giving women the opportunity to have children after their menopause has also raised a lot of ethical issues. If women are having children in to their late 50’s 60’s then this raises questions as to their physical capability of having a child, carry it during pregnancy and caring for it once its born.

Alternative solutions

IVF is currently being used to help people overcome infertility. During IVF an egg and sperm are combined ex-vivo (in the lab) and then artificially inseminated into the women. The benefits of this solution are is the technology is currently available and used by approximately 37,000 women a year with 4,700 cycles in the UK, of which 1,100 had successful births. [8]. Unfortunately, this shows success rates are low, with an average of a 23.7%, when each round of IVF cost approximately £6,000, the success rate is poor, even after years of continual research and improvements. Another disadvantage to this method is that if the female is not producing any useable eggs, using IVF to give her a biological child is almost impossible, forcing the couple to use and egg donor. Similarly if male is unable to produce sperm the couple will have to use a sperm donor, meaning the child is not biologically one of the parents. If both partners in the couple are not producing the necessary cells then it could mean the have to use egg and sperm donors, meaning it is not biologically related to either of them.

Another solution is to take fertility drugs; if the woman is ovulating irregularly it can trigger egg production. It triggers it in a similar in which it happens naturally with your own body’s hormones. It is known as ovulation induction. They can be used along side other types of fertility treatment but the can be effective on their own. They are effective if your cycle is irregular, you aren’t producing any or few eggs or if your infertility is caused by failure of the pituitary gland. The advantages to this solution is that it is completely non-invasive, you simply have to take the drug as prescribed and you have increased chances of conceiving naturally. The issues with this form of treatment are: you could have a reaction to the type of drug suitable for your condition. Ovarian hyper-stimulation syndrome, this is where Cysts develop on the ovaries and fluid collects in the abdomen. It can be potentially fatal. [9]

Bibliography

1. BBC News (June 2005) ‘Life created from eggs made from stem cells’ by James Gallagher, [accessed 29th October]

2. About.com (October 2012) ‘What are the chances of IVF success?’ by Rachael Gurevich [accessed 29th October]

3. Dr Christopher M. Kirton Ph.D. Head of Operations (Cellular Genetics), Wellcome Trust Sanger Institute, this was an interview based discussion.

4.Baby Centre (April 2011) [accessed 29th October]

5. Stem cell information (2009) ‘Introduction: What are stem cells, and why are they important?’ section. [accessed on the 23 October 2012]

6. Stem cell information (2009) ‘What are induced pluripotent stem cells?’ section. [accessed on the 23 October 2012]

7. Offspring from Oocytes Derived from in vitro Primordial Germ Cell–like Cells in Mice – Hyashi K, Paper on the fundamental experiment.

8. HFEA [accessed on the 23 October 2012]

Source Evaluation

3. Dr Christopher M. Kirton Ph.D. Head of Operations (Cellular Genetics)

The information obtained from Dr Christopher M. Kirton was given through explanation from him and notes I took during the interview style discussion. I trust this source as Dr. Christopher Kirton has been working in this field for many years and is now 2nd from the top in the chain of command for the operational side of the Wellcome Trust Sanger Institute (WTSI) and head of Cellular Genetics. He has had a few jobs, working his way up to where he is now, he started as a senior research associate at Cambridge university, running a small (3 person) team of scientists, he then took the Head of Department's role at NDA setting up and then running a group which started at 16 people but then got up to near 40 with a budget of £2 million. After that he got a promotion to a strategic management position within NDA and ran the biologics business (large molecule drugs like antibodies and vaccines). No direct reports in that role but he had matrix responsibilities for about 150 people and a budget of about £5 million. He is currently Head of Operations at the WTSI, he’s setting up a brand new core facility for the institute, not that many people at the moment (just 16) but the budget is larger, £30 million. He has a reputation based on his publications, he has 9 first author papers and has also written chapter in a textbook. He has also presented at a number of high profile scientific conferences and was part of the UK Science and technology mission to Japan, which resulted in him presenting at the British Embassy in Tokyo. This gives me reason to believe the information obtained

7. Offspring from Oocytes derived from in vitro Primordial Germ Cell–like Cells in Mice – Hyashi K

This is the paper on the experiments that lead to this breakthrough in science, Dr Katsuhiko Hayashi has done a lot of work in this field, including, , which leads to his research in this field. The paper is published on the web so is therefore open to be readily criticized by other scientists in order for it to improve. They have repeated the experiment over and over again, using less and lees subjects each time, originally starting with 50,000 gonadal somatic cells and eventually ending in using 10,000. The paper has a large amount of sources from reputable leading scientists indicating that large amounts of work and research have gone into it. Everything is documented in large amounts of detail with photographs (see below) and diagrams of the results and methodology of the experiments. It was published in the online science magazine.